Gene Summary

Gene:ALDH1A1; aldehyde dehydrogenase 1 family, member A1
Aliases: ALDC, ALDH1, HEL-9, HEL12, PUMB1, ALDH11, RALDH1, ALDH-E1, HEL-S-53e
Summary:The protein encoded by this gene belongs to the aldehyde dehydrogenase family. Aldehyde dehydrogenase is the next enzyme after alcohol dehydrogenase in the major pathway of alcohol metabolism. There are two major aldehyde dehydrogenase isozymes in the liver, cytosolic and mitochondrial, which are encoded by distinct genes, and can be distinguished by their electrophoretic mobility, kinetic properties, and subcellular localization. This gene encodes the cytosolic isozyme. Studies in mice show that through its role in retinol metabolism, this gene may also be involved in the regulation of the metabolic responses to high-fat diet. [provided by RefSeq, Mar 2011]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:retinal dehydrogenase 1
Source:NCBIAccessed: 27 February, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 27 February 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 27 February, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: ALDH1A1 (cancer-related)

Yasuda K, Torigoe T, Mariya T, et al.
Fibroblasts induce expression of FGF4 in ovarian cancer stem-like cells/cancer-initiating cells and upregulate their tumor initiation capacity.
Lab Invest. 2014; 94(12):1355-69 [PubMed] Related Publications
Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are defined as a small population of cells within cancer that contribute to cancer initiation and progression. Cancer-associated fibroblasts (CAFs) are stromal fibroblasts surrounding tumor cells, and they have important roles in tumor growth and tumor progression. It has been suggested that stromal fibroblasts and CSCs/CICs might mutually cooperate to enhance their growth and tumorigenic capacity. In this study, we investigated the effects of fibroblasts on tumor-initiating capacity and stem-like properties of ovarian CSCs/CICs. CSCs/CICs were isolated from the ovarian carcinoma cell line HTBoA as aldehyde dehydrogenase 1 high (ALDH1(high)) population by the ALDEFLUOR assay. Histological examination of tumor tissues derived from ALDH1(high) cells revealed few fibrous stroma, whereas those derived from fibroblast-mixed ALDH1(high) cells showed abundant fibrous stroma formation. In vivo tumor-initiating capacity and in vitro sphere-forming capacity of ALDH1(high) cells were enhanced in the presence of fibroblasts. Gene expression analysis revealed that fibroblast-mixed ALDH1(high) cells had enhanced expression of fibroblast growth factor 4 (FGF4) as well as stemness-associated genes such as SOX2 and POU5F1. Sphere-forming capacity of ALDH1(high) cells was suppressed by small-interfering RNA (siRNA)-mediated knockdown of FGFR2, the receptor for FGF4 which was expressed preferentially in ALDH1(high) cells. Taken together, the results indicate that interaction of fibroblasts with ovarian CSCs/CICs enhanced tumor-initiating capacity and stem-like properties through autocrine and paracrine FGF4-FGFR2 signaling.

Ning G, Bijron JG, Yamamoto Y, et al.
The PAX2-null immunophenotype defines multiple lineages with common expression signatures in benign and neoplastic oviductal epithelium.
J Pathol. 2014; 234(4):478-87 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
The oviducts contain high-grade serous cancer (HGSC) precursors (serous tubal intraepithelial neoplasia or STINs), which are γ-H2AX(p) - and TP53 mutation-positive. Although they express wild-type p53, secretory cell outgrowths (SCOUTs) are associated with older age and serous cancer; moreover, both STINs and SCOUTs share a loss of PAX2 expression (PAX2(n) ). We evaluated PAX2 expression in proliferating adult and embryonic oviductal cells, normal mucosa, SCOUTs, Walthard cell nests (WCNs), STINs, and HGSCs, and the expression of genes chosen empirically or from SCOUT expression arrays. Clones generated in vitro from embryonic gynaecological tract and adult Fallopian tube were Krt7(p) /PAX2(n) /EZH2(p) and underwent ciliated (PAX2(n) /EZH2(n) /FOXJ1(p) ) and basal (Krt7(n) /EZH2(n) /Krt5(p) ) differentiation. Similarly, non-ciliated cells in normal mucosa were PAX2(p) but became PAX2(n) in multi-layered epithelium undergoing ciliated or basal (WCN) cell differentiation. PAX2(n) SCOUTs fell into two groups: type 1 were secretory or secretory/ciliated with a 'tubal' phenotype and were ALDH1(n) and β-catenin(mem) (membraneous only). Type 2 displayed a columnar to pseudostratified (endometrioid) phenotype, with an EZH2(p) , ALDH1(p) , β-catenin(nc) (nuclear and cytoplasmic), stathmin(p) , LEF1(p) , RCN1(p) , and RUNX2(p) expression signature. STINs and HGSCs shared the type 1 immunophenotype of PAX2(n) , ALDH1(n) , β-catenin(mem) , but highly expressed EZH2(p) , LEF1(p) , RCN1(p) , and stathmin(p) . This study, for the first time, links PAX2(n) with proliferating fetal and adult oviductal cells undergoing basal and ciliated differentiation and shows that this expression state is maintained in SCOUTs, STINs, and HGSCs. All three entities can demonstrate a consistent perturbation of genes involved in potential tumour suppressor gene silencing (EZH2), transcriptional regulation (LEF1), regulation of differentiation (RUNX2), calcium binding (RCN1), and oncogenesis (stathmin). This shared expression signature between benign and neoplastic entities links normal progenitor cell expansion to abnormal and neoplastic outgrowth in the oviduct and exposes a common pathway that could be a target for early prevention.

Chene G, Radosevic-Robin N, Tardieu AS, et al.
Morphological and immunohistochemical study of ovarian and tubal dysplasia associated with tamoxifen.
Eur J Histochem. 2014; 58(2):2251 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
Ovarian epithelial dysplasia was initially described in material from prophylactic oophorectomies for BReast CAncer gene (BRCA) mutation. Similar histopathological abnormalities have been revealed after ovulation stimulation. Given that tamoxifen (TAM) has a clomid-like effect and is sometimes used to induce ovulation, we studied the morphological features and immunohistochemical expression patterns of neoplasia-associated markers in adnexectomies previously exposed to TAM for breast cancer. We blindly reviewed 173 histopathological slides of adnexectomies according to three groups - oophorectomie sassociated with TAM exposure (n=42), oophorectomies associated with clomiphene exposure (n=15) and a spontaneously fertile non cancerous control group (n=116). Morphological features (with an ovarian and tubal dysplasia scoring system) and immunohistochemical expression patterns of Ki-67, p53 and Aldehyde dehydrogenase 1 (ALDH1 is an enzyme significantly associated with earlystage ovarian cancer) were evaluated and correlated. Mean tubal dysplasia score was significantly higher in the TAM group and clomiphene group than in controls (respectively 7.8 vs 3.5, P<0.007 and 6.8 vs 3.5, P=0.008). There is no statistical difference for the ovarian score in TAM group in comparison with the control group whereas we found a significant score for clomiphen group (6.5, P=0.009). Increased ALDH1 expression was observed in the two exposed group whereas expression patterns of Ki67 and p53 were moderate. Interestingly, ALDH1 expression was low in non-dysplastic epithelium, high in dysplasia, and constantly low in the two carcinoma. Furthermore, we confirm our previous results showing that ALDH1 may be a useful tissue biomarker in the subtle histopathological diagnosis of tubo-ovarian dysplasia.

Sun Y, Wang Y, Fan C, et al.
Estrogen promotes stemness and invasiveness of ER-positive breast cancer cells through Gli1 activation.
Mol Cancer. 2014; 13:137 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
BACKGROUND: Although long-term estrogen (E2) exposure is associated with increased breast cancer (BC) risk, and E2 appears to sustain growth of BC cells that express functional estrogen receptors (ERs), its role in promoting BC stem cells (CSCs) remains unclear. Considering that Gli1, part of the Sonic hedgehog (Shh) developmental pathway, has been shown to mediate CSCs, we investigated whether E2 and Gli1 could promote CSCs and epithelial-mesenchymal transition (EMT) in ER+ BC cell lines.
METHODS: We knocked down Gli1 in several BC cells using a doxycycline-controlled vector, and compared Gli1-knockdown cells and Gli1+ cells in behavior and expression of ER, Gli1, ALDH1 (BC-CSC marker), Shh, Ptch1 (Shh receptor) and SOX2, Nanog and Bmi-1 (CSC-associated transcriptions factors), using PCR; tissue microarrays, western blot; chromatin immunoprecipitation q-PCR, confocal immunofluorescence microscopy; fluorescence-activated cell sorting; annexin-flow cytometry (for apoptosis); mammosphere culture; and colony formation, immunohistochemistry, Matrigel and wound-scratch assays.
RESULTS: Both mRNA and protein expressions of ER correlated with those of Gli1 and ALDH1. E2 induced Gli1 expression only in ER+ BC cells. E2 promoted CSC renewal, invasiveness and EMT in ER+/Gli1+ cells but not in Gli1-knockdown cells.
CONCLUSIONS: Our results indicate that estrogen acts via Gli1 to promote CSC development and EMT in ER+ BC cells. These findings also imply that Gli1 mediates cancer stem cells, and thus could be a target of a novel treatment for ER+ breast cancer.

Mannoor K, Shen J, Liao J, et al.
Small nucleolar RNA signatures of lung tumor-initiating cells.
Mol Cancer. 2014; 13:104 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
BACKGROUND: Non-small cell lung cancer (NSCLC) is the number one cancer killer. Tumor-initiating cells (TICs) are responsible for tumor progression and recurrence. Emerging evidences suggest that small nucleolar RNAs (snoRNAs) play malfunctioning roles in lung tumorigenesis. This study aims to determine if snoRNAs have important function in lung TICs by: 1) profiling and comparing snoRNA expression patterns in lung ALDH1+/- cells of 28 primary NSCLC tissues to identify new signatures of TICs; 2) determining prognostic significance of the snoRNA signatures by analyzing the expression in 82 NSCLC tissues with different stages and histological types using quantitative PCR; 3) functionally investigating if the snoRNAs contribute to stemness of lung TICs using in vitro and in vivo assays.
RESULTS: Twenty-two snoRNAs were identified whose changes were specific to the TICs. The expression of two snoRNAs (snoRA3 and snoRA42) was inversely associated with survival of NSCLC patients (P = 0.002, p = 0.001, respectively). Functional analysis indicated that snoRA42 was upregulated in CD133+ cells isolated from NSCLC cell lines compared with the CD133- counterparts. snoRA42 knockdown reduced the proliferation and self-renewal of TICs in vitro. However, ectopic expression of snoRA42 in non-TICs enhanced the potentials of cell proliferation and self-renewal. snoRA42 expression was associated with expression of stem cell-core transcription factors in lung TICs. Blocking snoRA42 expression in TIC xenografts decreased tumorigenesis in mice.
CONCLUSIONS: The snoRNA signatures of lung TICs provide potential biomarkers for predicting outcome of NSCLC. snoRA42 is one of the important snoRNAs in regulating features of lung TICs, and thus contributes to lung tumorigenesis.

He KF, Zhang L, Huang CF, et al.
CD163+ tumor-associated macrophages correlated with poor prognosis and cancer stem cells in oral squamous cell carcinoma.
Biomed Res Int. 2014; 2014:838632 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
Tumor-associated macrophages (TAMs) play an important role in the progression and prognostication of numerous cancers. However, the role and clinical significance of TAM markers in oral squamous cell carcinoma (OSCC) has not been elucidated. The present study was designed to investigate the correlation between the expression of TAM markers and pathological features in OSCC by tissue microarray. Tissue microarrays containing 16 normal oral mucosa, 6 oral epithelial dysplasia, and 43 OSCC specimens were studied by immunohistochemistry. We observed that the protein expression of the TAM markers CD68 and CD163 as well as the cancer stem cell (CSC) markers ALDH1, CD44, and SOX2 increased successively from the normal oral mucosa to OSCC. The expressions of CD68 and CD163 were significantly associated with lymph node status, and SOX2 was significantly correlated with pathological grade and lymph node status, whereas ALDH1 was correlated with tumor stage. Furthermore, CD68 was significantly correlated with CD163, SOX2, and ALDH1 (P < 0.05). Kaplan-Meier analysis revealed that OSCC patients overexpressing CD163 had significantly worse overall survival (P < 0.05). TAM markers are associated with cancer stem cell marker and OSCC overall survival, suggesting their potential prognostic value in OSCC.

Wang X, Hu JF, Tan Y, et al.
Cancer stem cell marker Musashi-1 rs2522137 genotype is associated with an increased risk of lung cancer.
PLoS One. 2014; 9(5):e95915 [PubMed] Article available free on PMC after 01/12/2015 Related Publications
Gene single nucleotide polymorphisms (SNPs) have been extensively studied in association with development and prognosis of various malignancies. However, the potential role of genetic polymorphisms of cancer stem cell (CSC) marker genes with respect to cancer risk has not been examined. We conducted a case-control study involving a total of 1000 subjects (500 lung cancer patients and 500 age-matched cancer-free controls) from northeastern China. Lung cancer risk was analyzed in a logistic regression model in association with genotypes of four lung CSC marker genes (CD133, ALDH1, Musashi-1, and EpCAM). Using univariate analysis, the Musashi-1 rs2522137 GG genotype was found to be associated with a higher incidence of lung cancer compared with the TT genotype. No significant associations were observed for gene variants of CD133, ALDH1, or EpCAM. In multivariate analysis, Musashi-1 rs2522137 was still significantly associated with lung cancer when environmental and lifestyle factors were incorporated in the model, including lower BMI; family history of cancer; prior diagnosis of chronic obstructive pulmonary disease, pneumonia, or pulmonary tuberculosis; occupational exposure to pesticide; occupational exposure to gasoline or diesel fuel; heavier smoking; and exposure to heavy cooking emissions. The value of the area under the receiver-operating characteristic (ROC) curve (AUC) was 0.7686. To our knowledge, this is the first report to show an association between a Musashi-1 genotype and lung cancer risk. Further, the prediction model in this study may be useful in determining individuals with high risk of lung cancer.

Goossens-Beumer IJ, Zeestraten EC, Benard A, et al.
Clinical prognostic value of combined analysis of Aldh1, Survivin, and EpCAM expression in colorectal cancer.
Br J Cancer. 2014; 110(12):2935-44 [PubMed] Article available free on PMC after 10/06/2015 Related Publications
BACKGROUND: Tumour aggressiveness might be related to the degree of main cancer hallmark acquirement of tumour cells, reflected by expression levels of specific biomarkers. We investigated the expression of Aldh1, Survivin, and EpCAM, together reflecting main cancer hallmarks, in relation to clinical outcome of colorectal cancer (CRC) patients.
METHODS: Immunohistochemistry was performed using a tumour tissue microarray of TNM (Tumour, Node, Metastasis)-stage I-IV CRC tissues. Single-marker expression or their combination was assessed for associations with the clinical outcome of CRC patients (N=309).
RESULTS: Increased expression of Aldh1 or Survivin, or decreased expression of EpCAM was each associated with poor clinical outcome, and was therefore identified as clinically unfavourable expression. Analyses of the combination of all three markers showed worse clinical outcome, specifically in colon cancer patients, with an increasing number of markers showing unfavourable expression. Hazard ratios ranged up to 8.3 for overall survival (P<0.001), 36.6 for disease-specific survival (P<0.001), and 27.1 for distant recurrence-free survival (P<0.001).
CONCLUSIONS: Our data identified combined expression levels of Aldh1, Survivin, and EpCAM as strong independent prognostic factors, with high hazard ratios, for survival and tumour recurrence in colon cancer patients, and therefore reflect tumour aggressiveness.

Yan J, De Melo J, Cutz JC, et al.
Aldehyde dehydrogenase 3A1 associates with prostate tumorigenesis.
Br J Cancer. 2014; 110(10):2593-603 [PubMed] Article available free on PMC after 13/05/2015 Related Publications
BACKGROUND: Accumulating evidence demonstrates high levels of aldehyde dehydrogense (ALDH) activity in human cancer types, in part, because of its association with cancer stem cells. Whereas ALDH1A1 and ALDH7A1 isoforms were reported to associate with prostate tumorigenesis, whether other ALDH isoforms are associated with prostate cancer (PC) remains unclear.
METHODS: ALDH3A1 expression was analysed in various PC cell lines. Xenograft tumours and 54 primary and metastatic PC tumours were stained using immunohistochemistry for ALDH3A1 expression.
RESULTS: In comparison with the non-stem counterparts, a robust upregulation of ALDH3A1 was observed in DU145-derived PC stem cells (PCSCs). As DU145 PCSCs produced xenograft tumours with more advanced features compared with those derived from DU145 cells, higher levels of ALDH3A1 were detected in the former; a dramatic elevation of ALDH3A1 occurred in DU145 cell-derived lung metastasis compared with local xenograft tumours. Furthermore, while ALDH3A1 was not observed in prostate glands, ALDH3A1 was clearly present in PIN, and further increased in carcinomas. In comparison with the paired local carcinomas, ALDH3A1 was upregulated in lymph node metastatic tumours; the presence of ALDH3A1 in bone metastatic PC was also demonstrated.
CONCLUSIONS: We report here the association of ALDH3A1 with PC progression.

Ghezali L, Liagre B, Limami Y, et al.
Sonic Hedgehog activation is implicated in diosgenin-induced megakaryocytic differentiation of human erythroleukemia cells.
PLoS One. 2014; 9(4):e95016 [PubMed] Article available free on PMC after 13/05/2015 Related Publications
Differentiation therapy is a means to treat cancer and is induced by different agents with low toxicity and more specificity than traditional ones. Diosgenin, a plant steroid, is able to induce megakaryocytic differentiation or apoptosis in human HEL erythroleukemia cells in a dose-dependent manner. However, the exact mechanism by which diosgenin induces megakaryocytic differentiation has not been elucidated. In this study, we studied the involvement of Sonic Hedgehog in megakaryocytic differentiation induced by diosgenin in HEL cells. First, we showed that different elements of the Hedgehog pathway are expressed in our model by qRT-PCR. Then, we focused our interest on key elements in the Sonic Hedgehog pathway: Smoothened receptor, GLI transcription factor and the ligand Sonic Hedgehog. We showed that Smoothened and Sonic Hedgehog were overexpressed in disogenin-treated cells and that GLI transcription factors were activated. Then, we showed that SMO inhibition using siSMO or the GLI antagonist GANT-61, blocked megakaryocytic differentiation induced by diosgenin in HEL cells. Furthermore, we demonstrated that Sonic Hedgehog pathway inhibition led to inhibition of ERK1/2 activation, a major physiological pathway involved in megakaryocytic differentiation. In conclusion, our study reports, for the first time, a crucial role for the Sonic Hedgehog pathway in diosgenin-induced megakaryocytic differentiation in HEL cells.

Arend RC, Londoño-Joshi AI, Samant RS, et al.
Inhibition of Wnt/β-catenin pathway by niclosamide: a therapeutic target for ovarian cancer.
Gynecol Oncol. 2014; 134(1):112-20 [PubMed] Related Publications
Objective. The Wnt/β-catenin pathway is known to regulate cellular proliferation and plays a role in chemoresistance. Niclosamide, an FDA approved salicyclamide derivative used for the treatment of tapeworm infections, targets the Wnt/β-catenin pathway. Therefore, the objective of this study was to investigate niclosamide as a potential therapeutic agent for ovarian cancer. Methods. Tumor cells isolated from 34 patients' ascites with primary ovarian cancer were treated with niclosamide (0.1 to 5 μM) ± carboplatin (5 to 150 μM). Cell viability was assessed using the ATP-lite assay. LRP6, Axin 2, Cyclin D1, survivin and cytosolic free β-catenin levels were determined using Western blot analysis. Tumorspheres were treated, and Wnt transcriptional activity was measured by the TOPflash reporter assay. ALDH and CD133 were analyzed by Flow cytometry and IHC. ALDH1A1 and LRP6 were analyzed by IHC in solid tumor and in ascites before and after treatment with niclosamide. Results. Combination treatment produced increased cytotoxicity compared to single agent treatment in 32/34 patient samples. Western blot analysis showed a decrease in Wnt/β-catenin pathway proteins and the expression of target genes. A significant reduction of Wnt/β-catenin signaling was confirmed by TOPflash assay. There was increased staining of ALDH1A1 and LRP6 in ascites compared to solid tumor which decreased after treatment. Conclusion. This study demonstrates that niclosamide is a potent Wnt/β-catenin inhibitor. Targeting the Wnt/β-catenin pathway led to decreased cellular proliferation and increased cell death. These findings warrant further research of this drug and other niclosamide analogs as a treatment option for ovarian cancer.

Okada T, Nakamura T, Watanabe T, et al.
Coexpression of EpCAM, CD44 variant isoforms and claudin-7 in anaplastic thyroid carcinoma.
PLoS One. 2014; 9(4):e94487 [PubMed] Article available free on PMC after 13/05/2015 Related Publications
BACKGROUND: Anaplastic thyroid cancer is considered to be one of the most aggressive human malignancies, and the mean survival time after diagnosis is approximately six months, regardless of treatments. This study aimed to examine how EpCAM and its related molecules are involved in the characteristics of anaplastic thyroid carcinoma.
METHODOLOGY/PRINCIPAL FINDINGS: Two differentiated thyroid cancer cell lines (TPC-1 and FTC-133), and two anaplastic thyroid cancer cell lines (FRO, ACT-1) were analyzed for expression of CD44 standard isoform (CD44s), CD44 variant isoforms, and EpCAM, and human aldehyde dehydrogenase-1 (ALDH1) enzymatic activity using flow cytometry. CD44s expression was higher in TPC-1 and FTC-133 than in the FRO and ACT-1, whereas ALDH1 activities were higher in FRO and ACT-1 than in TPC-1 and FTC-133. An inverse correlation between CD44s expression and ALDH1 activity was observed in all thyroid cancer cell lines. As for the expressions of CD44 variant isoforms, ACT-1 showed higher and FRO showed moderate CD44v6 expressions, whereas either TPC-1 or FTC-133 showed negative CD44v6 expression. EpCAM expressions in FRO and ACT-1 were higher than those in TPC-1 and FTC-133, and EpCAM expressions inversely correlated with those of CD44s. A positive correlation was observed between EpCAM expression and ALDH1 activity in thyroid cancer cell lines. In the RT-PCR analysis, the expression levels of EpCAM, caludin-7 and ALDH1 in FRO and ATC-1 cells were significantly higher than those in TPC-1 and FTC-133 cells. In clinical specimens of thyroid cancers, nuclear expression of EpCAM and high expression of CD44v6 were detected significantly more frequently in anaplastic carcinomas.
CONCLUSIONS/SIGNIFICANCE: Our study suggests the possibility that EpCAM, together with CD44v6 and claudin-7 as well as ALDH1, may be involved in the development of the aggressive phenotype of anaplastic thyroid carcinoma. Our findings may suggest a novel therapeutic strategy for treatment of anaplastic thyroid carcinoma.

Sim SH, Kang MH, Kim YJ, et al.
P21 and CD166 as predictive markers of poor response and outcome after fluorouracil-based chemoradiotherapy for the patients with rectal cancer.
BMC Cancer. 2014; 14:241 [PubMed] Article available free on PMC after 13/05/2015 Related Publications
BACKGROUND: Pre-operative chemoradiotherapy (CRT) is the standard treatment in clinical stage T3/4 or node positive rectal cancer. However, there are no established biomarkers that can predict the pathological response and clinical outcome to CRT.
METHODS: Immunohistochemical staining was performed in tissue arrays constructed from core tissue specimens taken before treatment and from operative specimens from 112 patients who received 5-FU based pre-operative CRT and surgery. Expression of Ki67, TS, BAX, EpCAM, p53, p21, EGFR, CD44, CD133, CD166, HIF1α and ALDH1 were assessed and correlated with tumor regression grades and disease free survival.
RESULTS: Of the 112 patients (M/F 74/38, median age: 62), 20 (17.9%) patients achieved pathologic complete remission (pCR). In analyzing the associations between marker expressions and tumor regression grades, high p21 expression at the pretreatment biopsy was significantly associated with non-pCR (p = 0.022) and poor disease free survival (median DFS - low vs high p21: 75.8 vs 58.1 months, p = 0.002). In the multivariate analysis, high p21 expression level at the pre-treatment biopsy was significantly associated with poor DFS (p = 0.001, HR 6.14; 95% CI 2.03, 18.55). High CD166 expression level at the pretreatment biopsy was also associated with poor DFS (p = 0.003; HR 5.61; 95% CI 1.81, 17.35).
CONCLUSION: These show high p21 and CD166 expression at the pretreatment biopsy were associated with tumor regression and poor prognosis in patients treated with 5-FU based CRT. Larger, prospective and functional studies are warranted to determine the role of p21 and CD166 as predictive biomarker of response to CRT.

Parajuli B, Georgiadis TM, Fishel ML, Hurley TD
Development of selective inhibitors for human aldehyde dehydrogenase 3A1 (ALDH3A1) for the enhancement of cyclophosphamide cytotoxicity.
Chembiochem. 2014; 15(5):701-12 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Aldehyde dehydrogenase 3A1 (ALDH3A1) plays an important role in many cellular oxidative processes, including cancer chemoresistance, by metabolizing activated forms of oxazaphosphorine drugs such as cyclophosphamide (CP) and its analogues, such as mafosfamide (MF), ifosfamide (IFM), and 4-hydroperoxycyclophosphamide (4-HPCP). Compounds that can selectively target ALDH3A1 could permit delineation of its roles in these processes and could restore chemosensitivity in cancer cells that express this isoenzyme. Here we report the detailed kinetic and structural characterization of an ALDH3A1-selective inhibitor, CB29, previously identified in a high-throughput screen. Kinetic and crystallographic studies demonstrate that CB29 binds within the aldehyde substrate-binding site of ALDH3A1. Cellular proliferation of ALDH3A1-expressing lung adenocarcinoma (A549) and glioblastoma (SF767) cell lines, as well as ALDH3A1 non-expressing lung fibroblast (CCD-13Lu) cells, is unaffected by treatment with CB29 and its analogues alone. However, sensitivity toward the anti-proliferative effects of mafosfamide is enhanced by treatment with CB29 and its analogue in the tumor cells. In contrast, the sensitivity of CCD-13Lu cells toward mafosfamide was unaffected by the addition of these same compounds. CB29 is chemically distinct from the previously reported small-molecule inhibitors of ALDH isoenzymes and does not inhibit ALDH1A1, ALDH1A2, ALDH1A3, ALDH1B1, or ALDH2 isoenzymes at concentrations up to 250 μM. Thus, CB29 is a novel small molecule inhibitor of ALDH3A1, which might be useful as a chemical tool to delineate the role of ALDH3A1 in numerous metabolic pathways, including sensitizing ALDH3A1-positive cancer cells to oxazaphosphorines.

Duong HQ, Yi YW, Kang HJ, et al.
Combination of dasatinib and gemcitabine reduces the ALDH1A1 expression and the proliferation of gemcitabine-resistant pancreatic cancer MIA PaCa-2 cells.
Int J Oncol. 2014; 44(6):2132-8 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Gemcitabine-based chemotherapy is the standard for treatment of pancreatic cancer; however, intrinsic and acquired resistance to gemcitabine commonly occurs. Aldehyde dehydrogenase 1A1 (ALDH1A1), one of the characteristic features of tumor-initiating and/or cancer stem cell (CSC) properties, is important in both intrinsic and acquired resistance to gemcitabine. In this study, we investigated the effectiveness of dasatinib, an SRC inhibitor, and gemcitabine combination to inhibit the survivals of parental (MIA PaCa-2/P) and gemcitabine-resistant (MIA PaCa-2/GR) cell lines. In MIA PaCa-2/GR cells, the levels of phospho-SRC and ALDH1A1 were increased compared to MIA PaCa-2/P cells. Inhibition of SRC by dasatinib or siRNA synergistically enhanced gemcitabine-induced anti-proliferative effects and induced apoptotic cell death in these cells. Furthermore, combination of SRC inhibition (either by dasatinib or siRNA) and gemcitabine significantly decreased the levels of ALDH1A1 expression. These results suggest that dasatinib and gemcitabine combination may be a potential therapeutic strategy to overcome gemcitabine resistance by decreasing the levels of ALDH1A1 expression.

Kuželová K, Grebeňová D, Holoubek A, et al.
Group I PAK inhibitor IPA-3 induces cell death and affects cell adhesivity to fibronectin in human hematopoietic cells.
PLoS One. 2014; 9(3):e92560 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
P21-activated kinases (PAKs) are involved in the regulation of multiple processes including cell proliferation, adhesion and migration. However, the current knowledge about their function is mainly based on results obtained in adherent cell types. We investigated the effect of group I PAK inhibition using the compound IPA-3 in a variety of human leukemic cell lines (JURL-MK1, MOLM-7, K562, CML-T1, HL-60, Karpas-299, Jurkat, HEL) as well as in primary blood cells. IPA-3 induced cell death with EC50 ranging from 5 to more than 20 μM. Similar range was found for IPA-3-mediated dephosphorylation of a known PAK downstream effector, cofilin. The cell death was associated with caspase-3 activation, PARP cleavage and apoptotic DNA fragmentation. In parallel, 20 μM IPA-3 treatment induced rapid and marked decrease of the cell adhesivity to fibronectin. Per contra, partial reduction of PAK activity using lower dose IPA-3 or siRNA resulted in a slight increase in the cell adhesivity. The changes in the cell adhesivity were also studied using real-time microimpedance measurement and by interference reflection microscopy. Significant differences in the intracellular IPA-3 level among various cell lines were observed indicating that an active mechanism is involved in IPA-3 transport.

Panni RZ, Sanford DE, Belt BA, et al.
Tumor-induced STAT3 activation in monocytic myeloid-derived suppressor cells enhances stemness and mesenchymal properties in human pancreatic cancer.
Cancer Immunol Immunother. 2014; 63(5):513-28 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Pancreatic cancer (PC) mobilizes myeloid cells from the bone marrow to the tumor where they promote tumor growth and proliferation. Cancer stem cells (CSCs) are a population of tumor cells that are responsible for tumor initiation. Aldehyde dehydrogenase-1 activity in PC identifies CSCs, and its activity has been correlated with poor overall prognosis in human PC. Myeloid cells have been shown to impact tumor stemness, but the impact of immunosuppressive tumor-infiltrating granulocytic and monocytic myeloid-derived suppressor cells (Mo-MDSC) on ALDH1(Bright) CSCs and epithelial to mesenchymal transition is not well understood. In this study, we demonstrate that Mo-MDSC (CD11b(+)/Gr1(+)/Ly6G(-)/Ly6C(hi)) significantly increase the frequency of ALDH1(Bright) CSCs in a mouse model of PC. Additionally, there was significant upregulation of genes associated with epithelial to mesenchymal transition. We also found that human PC converts CD14(+) peripheral blood monocytes into Mo-MDSC (CD14(+)/HLA-DR(low/-)) in vitro, and this transformation is dependent on the activation of the STAT3 pathway. In turn, these Mo-MDSC increase the frequency of ALDH1(Bright) CSCs and promote mesenchymal features of tumor cells. Finally, blockade of STAT3 activation reversed the increase in ALDH1(Bright) CSCs. These data suggest that the PC tumor microenvironment transforms monocytes to Mo-MDSC by STAT3 activation, and these cells increase the frequency of ALDH1(Bright) CSCs. Therefore, targeting STAT3 activation may be an effective therapeutic strategy in targeting CSCs in PC.

Kropotova ES, Zinovieva OL, Zyryanova AF, et al.
Altered expression of multiple genes involved in retinoic acid biosynthesis in human colorectal cancer.
Pathol Oncol Res. 2014; 20(3):707-17 [PubMed] Related Publications
All-trans-retinoic acid (atRA), the oxidized form of vitamin A (retinol), regulates a wide variety of biological processes, such as cell proliferation and differentiation. Multiple alcohol, retinol and retinaldehyde dehydrogenases (ADHs, RDHs, RALDHs) as well as aldo-keto reductases (AKRs) catalyze atRA production. The reduced atRA biosynthesis has been observed in several human tumors, including colorectal cancer. However, subsets of atRA-synthesizing enzymes have not been determined in colorectal tumors. We investigated the expression patterns of genes involved in atRA biosynthesis in normal human colorectal tissues, primary carcinomas and cancer cell lines by RT-PCR. These genes were identified using transcriptomic data analysis (expressed sequence tags, RNA-sequencing, microarrays). Our results indicate that each step of the atRA biosynthesis pathway is dysregulated in colorectal cancer. Frequent and significant decreases in the mRNA levels of the ADH1B, ADH1C, RDHL, RDH5 and AKR1B10 genes were observed in a majority of colorectal carcinomas. The expression levels of the RALDH1 gene were reduced, and the expression levels of the cytochrome CYP26A1 gene increased. The human colon cancer cell lines showed a similar pattern of changes in the mRNA levels of these genes. A dramatic reduction in the expression of genes encoding the predominant retinol-oxidizing enzymes could impair atRA production. The most abundant of these genes, ADH1B and ADH1C, display decreased expression during progression from adenoma to early and more advanced stage of colorectal carcinomas. The diminished atRA biosynthesis may lead to alteration of cell growth and differentiation in the colon and rectum, thus contributing to the progression of colorectal cancer.

Krause U, Ryan DM, Clough BH, Gregory CA
An unexpected role for a Wnt-inhibitor: Dickkopf-1 triggers a novel cancer survival mechanism through modulation of aldehyde-dehydrogenase-1 activity.
Cell Death Dis. 2014; 5:e1093 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
It is widely accepted that canonical Wnt (cWnt) signaling is required for the differentiation of osteoprogenitors into osteoblasts. Furthermore, tumor-derived secretion of the cWnt-antagonist Dickkopf-1 (Dkk-1) is known to cause bone destruction, inhibition of repair and metastasis in many bone malignancies, but its role in osteosarcoma (OS) is still under debate. In this study, we examined the role of Dkk-1in OS by engineering its overexpression in the osteochondral sarcoma line MOS-J. Consistent with the known role of Dkk-1 in osteoblast differentiation, Dkk-1 inhibited osteogenesis by the MOSJ cells themselves and also in surrounding tissue when implanted in vivo. Surprisingly, Dkk-1 also had unexpected effects on MOSJ cells in that it increased proliferation and resistance to metabolic stress in vitro and caused the formation of larger and more destructive tumors than controls upon orthotopic implantation. These effects were attributed in part to upregulation of the stress response enzyme and cancer stem cell marker aldehyde-dehydrogenase-1 (ALDH1). Direct inhibition of ALDH1 reduced viability under stressful culture conditions, whereas pharmacological inhibition of cWnt or overexpression of ALDH1 had a protective effect. Furthermore, we observed that ALDH1 was transcriptionally activated in a c-Jun-dependent manner through a pathway consisting of RhoA, MAP-kinase-kinase-4 and Jun N-terminal Kinase (JNK), indicating that noncanonical planar cell polarity-like Wnt signaling was the mechanism responsible. Together, our results therefore demonstrate that Dkk-1 enhances resistance of OS cells to stress by tipping the balance of Wnt signaling in favor of the non-canonical Jun-mediated Wnt pathways. In turn, this results in transcriptional activation of ALDH1 through Jun-responsive promoter elements. This is the first report linking Dkk-1 to tumor stress resistance, further supporting the targeting of Dkk-1 not only to prevent and treat osteolytic bone lesions but also to reduce numbers of stress-resistant tumor cells.

Islam M, Sharma S, Teknos TN
RhoC regulates cancer stem cells in head and neck squamous cell carcinoma by overexpressing IL-6 and phosphorylation of STAT3.
PLoS One. 2014; 9(2):e88527 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
In this study we investigated the correlation between RhoC expression and cancer stem cells (CSCs) formation in head and neck squamous cell carcinoma (HNSCC). The inhibition of RhoC function was achieved using shRNA. The expression of stem cell surface markers, ALDH and CD44 were significantly low in two RhoC depleted HNSCC cell carcinoma cell lines. Furthermore, a striking reduction in tumorsphere formation was achieved in RhoC knockdown lines. The mRNA expression of RhoC in RhoC knockdown adherent and tumorspheres are dramatically down regulated as compared with the scrambled control. The mRNA expression of stem cell transcription factors; nanog, oct3/4 (Pouf1), and sox2 were significantly depleted in RhoC knockdown clones. Further, the phosphorylation of STAT3(ser727), and STAT3(tyr705) were significantly down regulated in RhoC knockdown clones. The overexpression of STAT3 in RhoC knockdown did not show any change in expression patterns of either-STAT3(tyr705) or stem cell transcription factors, signifying the role of RhoC in STAT3 activation and thus the expression of nanog, oct3/4 and sox2 in HNSCC. The expression of Inter leukin-6 (IL-6) in RhoC knockdown HNSCC cell lines was dramatically low as compared to the scrambled control. Further, we have shown a rescue in STAT3 phosphorylation by IL-6 stimulation in RhoC knockdown lines. This study is the first of its kind to establish the involvement of RhoC in STAT3 phosphorylation and hence in promoting the activation of core cancer stem cells (CSCs) transcription factors. These findings suggest that RhoC may be a novel target for HNSCC therapy.

Xu MH, Gao X, Luo D, et al.
EMT and acquisition of stem cell-like properties are involved in spontaneous formation of tumorigenic hybrids between lung cancer and bone marrow-derived mesenchymal stem cells.
PLoS One. 2014; 9(2):e87893 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
The most deadly phase in cancer progression is metastatic conversion. Epithelial-to-mesenchymal transition (EMT) is a key process by which cancer cells acquire invasive and metastatic phenotypes. In order to spawn macroscopic metastases, disseminated cancer cells would seem to require self-renewal capability. However, the underlying mechanism defining these processes is poorly understood. One possible mechanism underlying metastasis is fusion between myeloid cells and cancer cells. In this study, we found that spontaneously-formed tumorigenic hybrids between bone marrow-derived mesenchymal stem cells (MSCs) and three different non-small cell lung cancer (NSCLC) cell lines contributed to highly malignant subpopulations with both EMT and stem cell-like properties. Hybrids lost their epithelial morphology and assumed a fibroblast-like appearance. Up-regulation of vimentin, α-smooth muscle actin (α-SMA), and fibronectin, and down-regulation of E-cadherin and pancytokeratin were observed in tumorigenic hybrids. These cells also exhibited increased expression of the stem cell marker prominin-1 (CD133) and over-expression of transcription factors OCT4, Nanog, BMI1, Notch1, ALDH1 as well as Sox2, all genes responsible for regulating and maintaining the stem cell phenotype. In addition, in spontaneously-formed tumorigenic hybrids, increased pneumosphere-forming capacity and tumor-forming ability in NOD/SCID mice were detectable. Thus, cell fusion between lung cancer cells and MSCs provides a nonmutational mechanism that could contribute to aberrant gene expression patterns and give rise to highly malignant subpopulations both capable of EMT and with properties of cancer stem cells (CSCs).

Liu XF, Yang WT, Xu R, et al.
Cervical cancer cells with positive Sox2 expression exhibit the properties of cancer stem cells.
PLoS One. 2014; 9(1):e87092 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
BACKGROUND: Although Sox2 expression has been found in several types of cancer, it has not yet been used to identify or isolate CSCs in somatic carcinoma.
METHODS: SiHa and C33A cells stably transfected with a plasmid containing human Sox2 transcriptional elements driving the enhanced green fluorescent protein (EGFP) reporter were sorted into the Sox2-positive and the Sox2-negative populations by FACS, and Sox2 expression was detected by western blot and immunohistochemistry. The differentiation, self-renewal and tumor formation abilities, as well as the expression of the stemness and the EMT related genes of the Sox2-positive and the Sox2-negative cervical cancer cells were characterized in vitro and in vivo.
RESULTS: A pSox2/EGFP system was used to separate the Sox2-positive and the Sox2-negative cells from cervical cancer cell lines, SiHa and C33A cells. Compared with the Sox2-negative cells, the Sox2-positive SiHa and C33A cells exhibited greater capacities for self-renewal, differentiation and tumor formation. Furthermore, Sox2-positive SiHa and C33A cells expressed higher levels of stemness-related genes, such as Sox2/Bmi-1/Oct4/ALDH1, and EMT-related genes, such as vimentin/snail/β-catenin. Taken together, all these results indicated that cells expressing endogenous Sox2 are CSCs in cervical carcinomas.
CONCLUSION: This study is the first to establish a functional link between endogenous Sox2 expression and CSCs in cervical carcinomas. Additionally, this study demonstrated that it is feasible to develop a tool to isolate CSCs from somatic tumors based on the expression of the endogenous nuclear protein Sox2 instead of cell surface markers.

Murakami A, Takahashi F, Nurwidya F, et al.
Hypoxia increases gefitinib-resistant lung cancer stem cells through the activation of insulin-like growth factor 1 receptor.
PLoS One. 2014; 9(1):e86459 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Accumulating evidence indicates that a small population of cancer stem cells (CSCs) is involved in intrinsic resistance to cancer treatment. The hypoxic microenvironment is an important stem cell niche that promotes the persistence of CSCs in tumors. Our aim here was to elucidate the role of hypoxia and CSCs in the resistance to gefitinib in non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutation. NSCLC cell lines, PC9 and HCC827, which express the EGFR exon 19 deletion mutations, were exposed to high concentration of gefitinib under normoxic or hypoxic conditions. Seven days after gefitinib exposure, a small fraction of viable cells were detected, and these were referred to as "gefitinib-resistant persisters" (GRPs). CD133, Oct4, Sox2, Nanog, CXCR4, and ALDH1A1-all genes involved in stemness-were highly expressed in GRPs in PC9 and HCC827 cells, and PC9 GRPs exhibited a high potential for tumorigenicity in vivo. The expression of insulin-like growth factor 1 (IGF1) was also upregulated and IGF1 receptor (IGF1R) was activated on GRPs. Importantly, hypoxic exposure significantly increased sphere formation, reflecting the self-renewal capability, and the population of CD133- and Oct4-positive GRPs. Additionally, hypoxia upregulated IGF1 expression through hypoxia-inducible factor 1α (HIF1α), and markedly promoted the activation of IGF1R on GRPs. Knockdown of IGF1 expression significantly reduced phosphorylated IGF1R-expressing GRPs under hypoxic conditions. Finally, inhibition of HIF1α or IGF1R by specific inhibitors significantly decreased the population of CD133- and Oct4-positive GRPs, which were increased by hypoxia in PC9 and HCC827 cells. Collectively, these findings suggest that hypoxia increased the population of lung CSCs resistant to gefitinib in EGFR mutation-positive NSCLC by activating IGF1R. Targeting the IGF1R pathway may be a promising strategy for overcoming gefitinib resistance in EGFR mutation-positive NSCLC induced by lung CSCs and microenvironment factors such as tumor hypoxia.

Yu CH, Yu CC
Photodynamic therapy with 5-aminolevulinic acid (ALA) impairs tumor initiating and chemo-resistance property in head and neck cancer-derived cancer stem cells.
PLoS One. 2014; 9(1):e87129 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
BACKGROUND: Head and neck cancer (HNC) ranks the fourth leading malignancy and cancer death in male population in Taiwan. Despite recent therapeutic advances, the prognosis for HNC patients is still dismal. New strategies are urgently needed to improve the chemosensitization to conventional chemotherapeutic drugs and clinical responses of HNC patients. Studies have demonstrated that topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is being used in the treatment of various human premalignant and malignant lesions with some encouraging clinical outcomes. However, the molecular mechanisms of ALA-PDT in the therapeutic effect in HNC tumorigenesis and whether ALA-PDT as chemosensitizer for HNC treatment remain unclear. Accumulating data support cancer stem cells (CSCs) contributes chemo-resistance in HNC. Based on the previous studies, the purpose of the study is to investigate the effect of ALA-PDT on CSCs and chemosensitization property in HNC.
METHODOLOGY/PRINCIPAL FINDING: CSCs marker ALDH1 activity of HNC cells with ALA-PDT treatment as assessed by the Aldefluor assay flow cytometry analysis. Secondary Sphere-forming self-renewal, stemness markers expression, and invasiveness of HNC-CSCs with ALA-PDT treatment were presented. We observed that the treatment of ALA-PDT significantly down-regulated the ALDH1 activity and CD44 positivity of HNC-CSCs. Moreover, ALA-PDT reduced self-renewal property and stemness signatures expression (Oct4 and Nanog) in sphere-forming HNC-CSCs. ALA-PDT sensitized highly tumorigenic HNC-CSCs to conventional chemotherapies. Lastly, synergistic effect of ALA-PDT and Cisplatin treatment attenuated invasiveness/colongenicity property in HNC-CSCs.
CONCLUSION/SIGNIFICANCE: Our results provide insights into the clinical prospect of ALA-PDT as a potential chemo-adjuvant therapy against head and neck cancer through eliminating CSCs property.

Kim YH, Kim G, Kwon CI, et al.
TWIST1 and SNAI1 as markers of poor prognosis in human colorectal cancer are associated with the expression of ALDH1 and TGF-β1.
Oncol Rep. 2014; 31(3):1380-8 [PubMed] Related Publications
Epithelial-mesenchymal transition (EMT) is an important factor in cancer invasiveness and metastatic progression. During EMT, cancer cells acquire stem cell properties. The role of EMT and stemness in colon cancer has not been fully understood. We aimed to demonstrate the clinical significance of EMT and the stem cell phenotype in colorectal cancer. Two hundred and thirty-one surgically resected colon cancer cases were included in the present study. mRNAs of E-cadherin, TWIST1 and SNAI1 were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) (n=109). Immunohistochemical staining was performed for six markers (ALDH1, TGF-β1, E-cadherin, β-catenin, TWSIT1 and SNAI1) (n=231). We assessed clinicopathological characteristics according to the expression of the stem cell phenotype and EMT markers. Based on the results of qRT-PCR, TWIST1 and SNAI1 significantly influenced node metastasis (P=0.04 and P=0.02, respectively). High TWIST1 and SNAI1 mRNA expression was associated with poor overall survival according to the univariate analysis (P<0.01 and P=0.01, respectively) and the multivariate analysis (P=0.04 and P=0.04, respectively). ALDH1 expression as detected by immunohistochemical staining was associated with high nodal stage, advanced clinical stage, lymphatic invasion and poor survival (P=0.01, P=0.04, P<0.05 and P<0.01, respectively) and with the expression of TGF-β1 and β-catenin. In conclusion, in human colorectal cancer, the EMT markers TWIST1 and SNAI1 are suggested as important markers of poor prognosis. Their expression is associated with the expression of putative stem cell marker ALDH1, and ALDH1 is associated with the expression of TGF-β1.

Ibrahim SA, Hassan H, Vilardo L, et al.
Syndecan-1 (CD138) modulates triple-negative breast cancer stem cell properties via regulation of LRP-6 and IL-6-mediated STAT3 signaling.
PLoS One. 2013; 8(12):e85737 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Syndecan-1 (CD138), a heparan sulfate proteoglycan, acts as a coreceptor for growth factors and chemokines and is a molecular marker associated with epithelial-mesenchymal transition during development and carcinogenesis. Resistance of Syndecan-1-deficient mice to experimentally-induced tumorigenesis has been linked to altered Wnt-responsive precursor cell pools, suggesting a potential role of Syndecan-1 in breast cancer cell stem function. However, the precise molecular mechanism is still elusive. Here, we decipher the functional impact of Syndecan-1 knockdown using RNA interference on the breast cancer stem cell phenotype of human triple-negative MDA-MB-231 and hormone receptor-positive MCF-7 cells in vitro employing an analytical flow cytometric approach. Successful Syndecan-1 siRNA knockdown was confirmed by flow cytometry. Side population measurement by Hoechst dye exclusion and Aldehyde dehydrogenase-1 activity revealed that Syndecan-1 knockdown in MDA-MB-231 cells significantly reduced putative cancer stem cell pools by 60% and 27%, respectively, compared to controls. In MCF-7 cells, Syndecan-1 depletion reduced the side population by 40% and Aldehyde dehydrogenase-1 by 50%, repectively. In MDA-MB-231 cells, the CD44(+)CD24(-/low) phenotype decreased significantly by 6% upon siRNA-mediated Syndecan-1 depletion. Intriguingly, IL-6, its receptor sIL-6R, and the chemokine CCL20, implicated in regulating stemness-associated pathways, were downregulated by >40% in Syndecan-1-silenced MDA-MB-231 cells, which showed a dysregulated response to IL-6-induced shifts in E-cadherin and vimentin expression. Furthermore, activation of STAT-3 and NFkB transcription factors and expression of a coreceptor for Wnt signaling, LRP-6, were reduced by >45% in Syndecan-1-depleted cells compared to controls. At the functional level, Syndecan-1 siRNA reduced the formation of spheres and cysts in MCF-7 cells grown in suspension culture. Our study demonstrates the viability of flow cytometric approaches in analyzing cancer stem cell function. As Syndecan-1 modulates the cancer stem cell phenotype via regulation of the Wnt and IL-6/STAT3 signaling pathways, it emerges as a promising novel target for therapeutic approaches.

Huang YH, Luo MH, Ni YB, et al.
Increased SOX2 expression in less differentiated breast carcinomas and their lymph node metastases.
Histopathology. 2014; 64(4):494-503 [PubMed] Related Publications
AIMS: SOX2 is a key regulatory gene in embryonic stem cells. Although it has been implicated in cancer progression, its role in breast carcinoma is poorly understood.
MATERIALS AND METHODS: Fifty-seven ductal carcinomas in situ (DCIS), 552 invasive breast carcinomas and 107 corresponding metastatic lymph nodes were evaluated immunohistochemically for the expression of SOX2. Its correlation with clinicopathological features, other biomarker profiles and patients' outcomes were analysed.
RESULTS: SOX2 was detected in 19.0% (105 of 552) of invasive breast carcinomas and 12.3% (seven of 57) of DCIS. Expression correlated with larger tumour size (P = 0.005) and higher grade (P = 0.002). It was associated negatively with ER (P = 0.015) and PR (P = 0.046) expression, but positively with Ki67 index (P = 0.013). Interestingly, it was also associated with neuroendocrine marker expression (synpatophysin and chromogranin/synaptophysin, P = 0.048 and 0.028, respectively). Expression appeared to be independent from that of common stem cell markers, namely CD44, CD24 and aldehyde dehydrogenase 1 (ALDH1). Furthermore, a higher rate of expression was observed in metastatic lymph nodes than in the corresponding primary tumours (P = 0.034). High SOX2 expression was correlated with poor disease-free survival (log-rank=9.489, P = 0.012) and was an independent prognostic factor (HR=2.918, P = 0.015) in patients with high nodal stages.
CONCLUSIONS: In summary, SOX2 expression was related to adverse breast carcinoma profile and poor outcome in selected patient groups.

Emori M, Tsukahara T, Murase M, et al.
High expression of CD109 antigen regulates the phenotype of cancer stem-like cells/cancer-initiating cells in the novel epithelioid sarcoma cell line ESX and is related to poor prognosis of soft tissue sarcoma.
PLoS One. 2013; 8(12):e84187 [PubMed] Article available free on PMC after 21/03/2015 Related Publications
Epithelioid sarcoma (ES) is a relatively rare, highly malignant soft tissue sarcoma. The mainstay of treatment is resection or amputation. Currently other therapeutic options available for this disease are limited. Therefore, a novel therapeutic option needs to be developed. In the present study, we established a new human ES cell line (ESX) and analyzed the characteristics of its cancer stem-like cells/cancer-initiating cells (CSCs/CICs) based on ALDH1 activity. We demonstrated that a subpopulation of ESX cells with high ALDH1 activity (ALDH(high) cells) correlated with enhanced clonogenic ability, sphere-formation ability, and invasiveness in vitro and showed higher tumorigenicity in vivo. Next, using gene expression profiling, we identified CD109, a GPI-anchored protein upregulated in the ALDH(high) cells. CD109 mRNA was highly expressed in various sarcoma cell lines, but weakly expressed in normal adult tissues. CD109-positive cells in ESX predominantly formed spheres in culture, whereas siCD109 reduced ALDH1 expression and inhibited the cell proliferation in vitro. Subsequently, we evaluated the expression of CD109 protein in 80 clinical specimens of soft tissue sarcoma. We found a strong correlation between CD109 protein expression and the prognosis (P = 0.009). In conclusion, CD109 might be a CSC/CIC marker in epithelioid sarcoma. Moreover, CD109 is a promising prognostic biomarker and a molecular target of cancer therapy for sarcomas including ES.

Miyazaki S, Kikuchi H, Iino I, et al.
Anti-VEGF antibody therapy induces tumor hypoxia and stanniocalcin 2 expression and potentiates growth of human colon cancer xenografts.
Int J Cancer. 2014; 135(2):295-307 [PubMed] Related Publications
Tumor angiogenesis plays a critical role in colorectal cancer progression. Recent randomized clinical trials have revealed the additive effect of bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF)-A, to conventional chemotherapy in the improved survival of patients with metastatic colorectal cancer. However, a number of preclinical reports indicate the development of resistance to anti-angiogenic therapy. In this study, we addressed the effects of anti-VEGF antibodies on the growth and malignant behavior of colorectal cancer cells. TK-4, a solid tumor strain derived from a colon cancer patient, was subcutaneously or orthotopically implanted into nude mice. Short-term administration of anti-VEGF antibodies inhibited the growth of cecal tumors at day 14 by suppressing mitosis, but prolonged treatment resulted in the recovery of cellular proliferation and suppression of apoptosis at day 35. Intratumoral hypoxia induced by anti-VEGF antibody treatment resulted in activation of hypoxia inducible factor-1α protein and an increased number of aldehyde dehydrogenase 1-positive tumor cells. In microarray analysis, stanniocalcin 2 (STC2) was the most highly upregulated gene in anti-VEGF antibody-treated tumors. In vitro analyses showed that the growth and migration of SW480 colon cancer cells under hypoxic conditions were significantly inhibited by knockdown of STC2. In vivo serial transplantation of TK-4 revealed that long-term administration of anti-VEGF antibodies increased the tumorigenicity of colon cancers and accelerated tumor growth when transplanted into secondary recipient mice. Our data provide a potential molecular explanation for the limited clinical effectiveness of anti-VEGF antibodies.

Masui T, Ota I, Yook JI, et al.
Snail-induced epithelial-mesenchymal transition promotes cancer stem cell-like phenotype in head and neck cancer cells.
Int J Oncol. 2014; 44(3):693-9 [PubMed] Related Publications
Head and neck squamous cell carcinoma (HNSCC) is known to have a poor prognosis. The resistance to treatment and distant metastasis are important clinical problems in HNSCC. The epithelial-mesenchymal transition (EMT) is a key process in successful execution of many steps such as the invasion and metastasis for cancer cells. Snail is one of the master regulators that promote EMT in many types of malignancies including HNSCC. Recently, it has been shown that Snail-induced EMT could induce a cancer stem cell (CSC)‑like phenotype in a number of tumor types. In this study, we investigated the role of Snail in inducing EMT properties and CSC-like phenotype in HNSCC. We established HNSCC cell lines transfected with Snail. E-cadherin was analyzed using western blot analysis and immunofluorescence staining. Cell migration and invasion were assessed using wound-healing assay and modified Boyden chamber assay, respectively. CSC markers of HNSCC, CD44 and aldehyde dehydrogenase 1 (ALDH1), were also evaluated with western blot analysis, and chemosensitivity was assessed with WST-8 assay. Introduction of Snail induced EMT properties in HNSCC cells and enhanced cell migration and invasion. Moreover, Snail-induced EMT gained CSC-like phenotype and was associated with increased chemoresistance. These results suggest that Snail could be one of the attractive targets for the development of therapeutic strategies in HNSCC.

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