Gene Summary

Gene:ACTA2; actin, alpha 2, smooth muscle, aorta
Aliases: AAT6, ACTSA, MYMY5
Summary:The protein encoded by this gene belongs to the actin family of proteins, which are highly conserved proteins that play a role in cell motility, structure and integrity. Alpha, beta and gamma actin isoforms have been identified, with alpha actins being a major constituent of the contractile apparatus, while beta and gamma actins are involved in the regulation of cell motility. This actin is an alpha actin that is found in skeletal muscle. Defects in this gene cause aortic aneurysm familial thoracic type 6. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Nov 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:actin, aortic smooth muscle
Source:NCBIAccessed: 06 August, 2015


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 August 2015 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: ACTA2 (cancer-related)

Matsuoka Y, Yoshida R, Nakayama H, et al.
The tumour stromal features are associated with resistance to 5-FU-based chemoradiotherapy and a poor prognosis in patients with oral squamous cell carcinoma.
APMIS. 2015; 123(3):205-14 [PubMed] Related Publications
It has been increasingly recognized that the tumour microenvironment is a critical factor involved in cancer progression. However, little is known about the clinical value of the stromal features in oral squamous cell carcinoma (OSCC). The purpose of this study was to determine the clinical significance of cancer-associated fibroblasts (CAFs) and tumour-associated macrophages (TAMs) in OSCC. OSCC specimens were obtained from 60 patients who underwent surgery following 5-fluorouracil-based chemoradiotherapy. Paraffin-embedded sections obtained from biopsy specimens were immunohistochemically analysed. The associations among CAFs, TAMs and various clinicopathological features were examined, and the effects of CAFs and TAMs on the prognosis were evaluated. In the group with a high level of CAFs, the incidence of advanced pT- and pN-stage cases was significantly higher than that in the group with the low level. A high TAMs tumour expression was significantly correlated with a poor response to preoperative chemoradiotherapy. A Kaplan-Meier analysis revealed that higher numbers of CAFs and TAMs were significantly correlated with a poor prognosis. These findings suggest that TAMs are a potential biomarker for predicting the clinical response to 5-FU-based chemoradiotherapy, and the expression status of the CAFs and TAMs may be useful for making treatment decisions to improve the survival of OSCC patients.

Galván JA, García-Martínez J, Vázquez-Villa F, et al.
Validation of COL11A1/procollagen 11A1 expression in TGF-β1-activated immortalised human mesenchymal cells and in stromal cells of human colon adenocarcinoma.
BMC Cancer. 2014; 14:867 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The human COL11A1 gene has been shown to be up-regulated in stromal cells of colorectal tumours, but, so far, the immunodetection of procollagen 11A1, the primary protein product of COL11A1, has not been studied in detail in human colon adenocarcinomas. Some cancer-associated stromal cells seem to be derived from bone marrow mesenchymal cells; the expression of the COL11A1 gene and the parallel immunodetection of procollagen 11A1 have not been evaluated in these latter cells, either.
METHODS: We used quantitative RT-PCR and/or immunocytochemistry to study the expression of DES/desmin, VIM/vimentin, ACTA2/αSMA (alpha smooth muscle actin) and COL11A1/procollagen 11A1 in HCT 116 human colorectal adenocarcinoma cells, in immortalised human bone marrow mesenchymal cells and in human colon adenocarcinoma-derived cultured stromal cells. The immunodetection of procollagen 11A1 was performed with the new recently described DMTX1/1E8.33 mouse monoclonal antibody. Human colon adenocarcinomas and non-malignant colon tissues were evaluated by immunohistochemistry as well. Statistical associations were sought between anti-procollagen 11A1 immunoscoring and patient clinicopathological features.
RESULTS: Procollagen 11A1 was immunodetected in human bone marrow mesenchymal cells and in human colon adenocarcinoma-associated spindle-shaped stromal cells but not in colon epithelial or stromal cells of the normal colon. This immunodetection paralleled, in both kinds of cells, that of the other mesenchymal-related biomarkers studied: vimentin and alpha smooth muscle actin, but not desmin. Thus, procollagen 11A1(+) adenocarcinoma-associated stromal cells are similar to "activated myofibroblasts". In the series of human colon adenocarcinomas here studied, a high procollagen 11A1 expression was associated with nodal involvement (p = 0.05), the development of distant metastases (p = 0.017), and advanced Dukes stages (p = 0.047).
CONCLUSION: The immunodetection of procollagen 11A1 in cancer-associated stromal cells could be a useful biomarker for human colon adenocarcinoma characterisation.

Falcão AS, Kataoka MS, Ribeiro NA, et al.
A novel cell line derived from pleomorphic adenoma expresses MMP2, MMP9, TIMP1, TIMP2, and shows numeric chromosomal anomalies.
PLoS One. 2014; 9(8):e105231 [PubMed] Free Access to Full Article Related Publications
Pleomorphic adenoma is the most common salivary gland neoplasm, and it can be locally invasive, despite its slow growth. This study aimed to establish a novel cell line (AP-1) derived from a human pleomorphic adenoma sample to better understand local invasiveness of this tumor. AP-1 cell line was characterized by cell growth analysis, expression of epithelial and myoepithelial markers by immunofluorescence, electron microscopy, 3D cell culture assays, cytogenetic features and transcriptomic study. Expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) was also analyzed by immunofluorescence and zymography. Furthermore, epithelial and myoepithelial markers, MMPs and TIMPs were studied in the tumor that originated the cell line. AP-1 cells showed neoplastic epithelial and myoepithelial markers, such as cytokeratins, vimentin, S100 protein and smooth-muscle actin. These molecules were also found in vivo, in the tumor that originated the cell line. MMPs and TIMPs were observed in vivo and in AP-1 cells. Growth curve showed that AP-1 exhibited a doubling time of 3.342 days. AP-1 cells grown inside Matrigel recapitulated tumor architecture. Different numerical and structural chromosomal anomalies were visualized in cytogenetic analysis. Transcriptomic analysis addressed expression of 7 target genes (VIM, TIMP2, MMP2, MMP9, TIMP1, ACTA2 e PLAG1). Results were compared to transcriptomic profile of non-neoplastic salivary gland cells (HSG). Only MMP9 was not expressed in both libraries, and VIM was expressed solely in AP-1 library. The major difference regarding gene expression level between AP-1 and HSG samples occurred for MMP2. This gene was 184 times more expressed in AP-1 cells. Our findings suggest that AP-1 cell line could be a useful model for further studies on pleomorphic adenoma biology.

Liszka L
Ductal adenocarcinoma of the pancreas usually retained SMAD4 and p53 protein status as well as expression of epithelial-to-mesenchymal transition markers and cell cycle regulators at the stage of liver metastasis.
Pol J Pathol. 2014; 65(2):100-12 [PubMed] Related Publications
There are limited data on the biology of metastatic pancreatic ductal adenocarcinoma (PDAC). The aim of the present study was to compare the expression of immunohistochemical markers that may be involved in the development of metastatic disease in primary PDAC and in synchronous liver metastatic tissues. Thirty-two stains (corresponding to proteins encoded by 31 genes: SMAD4, TP53, ACTA2, CDH1, CDKN1A, CLDN1, CLDN4, CLDN7, CTNNB1, EGFR, ERBB2, FN1, KRT19, MAPK1/MAPK3, MAPK14, MKI67, MMP2, MMP9, MUC1 (3 antibodies), MUC5AC, MUC6, MTOR, MYC, NES, PTGS2, RPS6, RPS6KB1, TGFB1, TGFBR1, VIM) were evaluated using tissue microarray of 26 pairs of primary PDACs and their liver metastases. There were no significant differences in expression levels of examined proteins between primary and secondary lesions. In particular, metastatic PDAC retained the primary tumour's SMAD4 protein status in all and p53 protein status in all but one case. This surprising homogeneity also involved expression levels of markers of epithelial-to-mesenchymal transition as well as cell cycle regulators studied. In conclusion, the biological profiles of primary PDACs and their liver metastases seemed to be similar. Molecular alterations of PDAC related to a set of immunohistochemical markers examined in the present study were already present at the stage of localized disease.

Fu Z, Song P, Li D, et al.
Cancer-associated fibroblasts from invasive breast cancer have an attenuated capacity to secrete collagens.
Int J Oncol. 2014; 45(4):1479-88 [PubMed] Related Publications
Normal fibroblasts produce extracellular matrix (ECM) components that form the structural framework of tissues. Cancer-associated fibroblasts (CAFs) with an activated phenotype mainly contribute to ECM deposition and construction of cancer masses. However, the stroma of breast cancer tissues has been shown to be more complicated, and the mechanisms through which CAFs influence ECM deposition remain elusive. In this study, we found that the activated fibroblast marker α-smooth muscle actin (α-SMA) was only present in the stroma of breast cancer tissue, and the CAFs isolated from invasive breast cancer sample remained to be activated and proliferative in passages. To further assess the difference between CAFs and normal breast fibroblasts (NFs), MALDI TOF/TOF‑MS was used to analyze the secretory proteins of primary CAFs and NFs. In total, 2,903 and 3,023 proteins were identified. Mass spectrum quantitative assay and data analysis for extracellular proteins indicated that the CAFs produce less collagens and matrix-degrading enzymes compared with NFs. This finding was confirmed by western blot analysis. Furthermore, we discovered that reduced collagen deposition was present in the stroma of invasive breast cancer. These studies showed that although CAFs from invasive breast cancer possess an activated phenotype, they secreted less collagen and induced less ECM deposition in cancer stroma. In cancer tissue, the remodeling of stromal structure and tumor microenvironment might, therefore, be attributed to the biological changes in CAFs including their protein expression profile.

Chen Y, Zou L, Zhang Y, et al.
Transforming growth factor-β1 and α-smooth muscle actin in stromal fibroblasts are associated with a poor prognosis in patients with clinical stage I-IIIA nonsmall cell lung cancer after curative resection.
Tumour Biol. 2014; 35(7):6707-13 [PubMed] Related Publications
The aims of this study were to investigate the expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in surgical resection specimens from nonsmall cell lung cancer (NSCLC) and to evaluate the prognostic significance of this gene expression in stromal fibroblasts for patients with clinical stage I-IIIA NSCLC. The immunohistochemical expression of TGF-β1 and α-SMA was evaluated in 78 formalin-fixed paraffin-embedded tumor specimens from clinical stage I-IIIA NSCLC. Correlations between this gene expression and the clinicopathologic characteristics were determined by chi-square test. The prognostic impact of this gene expression in stromal fibroblasts with regard to overall survival (OS) was determined by Kaplan-Meier and Cox hazard proportional model. The percentages of high TGF-β1 expression in stromal fibroblasts and cancer cells were 19.2 % (15/78) and 35.9 % (28/78), respectively. There were 28.2 % (22/78) of patients with high α-SMA expression in stromal fibroblasts. The analysis revealed a significant positive association between TGF-β1 expression in stromal fibroblasts and in cancer cells (χ (2) = 4.86, p = 0.03). No significant association was found between TGF-β1 in cancer cells and α-SMA expression in stromal fibroblasts (χ (2) = 0.978, p = 0.326). The 3-year OS rates with low and high TGF-β1 expression in stromal fibroblasts were 52.4 and 26.7 %, respectively (χ (2) = 5.42, p = 0.019). The 3-year OS rates with low and high α-SMA expression in stromal fibroblasts were 53.9 and 31.0 %, respectively (χ (2) =5.01, p=0.025). The multivariate analysis revealed that clinical stage and TGF-β1 and α-SMA expression levels in stromal fibroblasts were identified as independent predictive factors of OS. The results suggest that the expression level of TGF-β1 and α-SMA in stromal fibroblasts may have prognostic significance in patients with clinical stage I-IIIA NSCLC after curative resection.

Kojima M, Higuchi Y, Yokota M, et al.
Human subperitoneal fibroblast and cancer cell interaction creates microenvironment that enhances tumor progression and metastasis.
PLoS One. 2014; 9(2):e88018 [PubMed] Free Access to Full Article Related Publications
BACKGROUNDS: Peritoneal invasion in colon cancer is an important prognostic factor. Peritoneal invasion can be objectively identified as periotoneal elastic laminal invasion (ELI) by using elastica stain, and the cancer microenvironment formed by the peritoneal invasion (CMPI) can also be observed. Cases with ELI more frequently show distant metastasis and recurrence. Therefore, CMPI may represent a particular milieu that facilitates tumor progression. Pathological and biological investigations into CMPI may shed light on this possibly distinctive cancer microenvironment.
METHODS: We analyzed area-specific tissue microarrays to determine the pathological features of CMPI, and propagated subperitoneal fibroblasts (SPFs) and submucosal fibroblasts (SMFs) from human colonic tissue. Biological characteristics and results of gene expression profile analyses were compared to better understand the peritoneal invasion of colon cancer and how this may form a special microenvironment through the interaction with SPFs. Mouse xenograft tumors, derived by co-injection of cancer cells with either SPFs or SMFs, were established to evaluate their active role on tumor progression and metastasis.
RESULTS: We found that fibrosis with alpha smooth muscle actin (α-SMA) expression was a significant pathological feature of CMPI. The differences in proliferation and gene expression profile analyses suggested SPFs and SMFs were distinct populations, and that SPFs were characterized by a higher expressions of extracellular matrix (ECM)-associated genes. Furthermore, compared with SMFs, SPFs showed more variable alteration in gene expressions after cancer-cell-conditioned medium stimulation. Gene ontology analysis revealed that SPFs-specific upregulated genes were enriched by actin-binding or contractile-associated genes including α-SMA encoding ACTA2. Mouse xenograft tumors derived by co-injection of cancer cells with SPFs showed enhancement of tumor growth, metastasis, and capacity for tumor formation compared to those derived from co-injection with cancer cells and SMFs.
CONCLUSIONS: CMPI is a special microenvironment, and interaction of SPFs and cancer cells within CMPI promote tumor growth and metastasis.

D'Anselmi F, Masiello MG, Cucina A, et al.
Microenvironment promotes tumor cell reprogramming in human breast cancer cell lines.
PLoS One. 2013; 8(12):e83770 [PubMed] Free Access to Full Article Related Publications
The microenvironment drives mammary gland development and function, and may influence significantly both malignant behavior and cell growth of mammary cancer cells. By restoring context, and forcing cells to properly interpret native signals from the microenvironment, the cancer cell aberrant behavior can be quelled, and organization re-established. In order to restore functional and morphological differentiation, human mammary MCF-7 and MDA-MB-231 cancer cells were allowed to grow in a culture medium filled with a 10% of the albumen (EW, Egg White) from unfertilized chicken egg. That unique microenvironment behaves akin a 3D culture and induces MCF-7 cells to produce acini and branching duct-like structures, distinctive of mammary gland differentiation. EW-treated MDA-MB-231 cells developed buds of acini and duct-like structures. Both MCF-7 and MDA-MB-231 cells produced β-casein, a key milk component. Furthermore, E-cadherin expression was reactivated in MDA-MB-231 cells, as a consequence of the increased cdh1 expression; meanwhile β-catenin - a key cytoskeleton component - was displaced behind the inner cell membrane. Such modification hinders the epithelial-mesenchymal transition in MDA-MB-231 cells. This differentiating pathway is supported by the contemporary down-regulation of canonical pluripotency markers (Klf4, Nanog). Given that egg-conditioned medium behaves as a 3D-medium, it is likely that cancer phenotype reversion could be ascribed to the changed interactions between cells and their microenvironment.

Luo Y, Cui X, Zhao J, et al.
Cells susceptible to epithelial-mesenchymal transition are enriched in stem-like side population cells from prostate cancer.
Oncol Rep. 2014; 31(2):874-84 [PubMed] Related Publications
Accumulating evidence suggests that epithelial-mesenchymal transition (EMT) acts as an important factor for the promotion of tumor progression. Strategies for suppressing EMT remain the subject of ongoing research. In the present study, fluorescence-activated cell sorting (FACS) was used to isolate side population (SP) cells from human prostate cancer (PCa) cell lines and xenograft tissues. After identifying their molecular and functional stem-like characteristics, stem-like SP cells from a cell line and from xenograft tissue were transfected with hypoxia inducible factor-1α (HIF-1α). The potential of the prostate stem-like SP cells to undergo EMT was compared with that in their bulk counterparts after HIF-1α introduction. Stem-like SP cells acquired more complete EMT molecular features and exhibited stronger aggressive capability than the homologous bulk population cells both in vitro (proliferation and invasion) and in vivo (tumorigenesis and metastasis formation). We, therefore, concluded that EMT is closely associated with tumor heterogeneity, and that PCa cells susceptible to EMT are enriched in stem-like SP cells. These findings disclose a new approach, targeting the cellular basis of the EMT process that may help to identify effective and accurate methods for suppressing tumor growth and preventing distant dissemination.

Xu LN, Xu BN, Cai J, et al.
Tumor-associated fibroblast-conditioned medium promotes tumor cell proliferation and angiogenesis.
Genet Mol Res. 2013; 12(4):5863-71 [PubMed] Related Publications
This study aimed to explore how tumor-associated fibroblasts (TAFs) promote the proliferation and angiogenesis of tumor cells via the paracrine mechanism in vitro. Conditioned media (CM) of ovarian TAFs and normal fibroblasts (NFs) were collected. Ovarian cancer cells (OCCs) were treated with 2 mL TAFs-CM and NFs-CM in experimental and control groups, respectively; 20 mM SB431512, a specific small molecule inhibitor of transforming growth factor-β (TGF-β), was added in the experimental group as the intervention group. The cell cycle was determined in each group. mRNA expressions of proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA), and vascular endothelial growth factor (VEGF), and protein expressions of α-SMA and VEGF were detected in each group. Proliferation of OCCs was significantly promoted in the experimental group compared with that of the control group. The proliferative effect was obviously inhibited in the intervention group. The mRNA expressions of PCNA, α-SMA, and VEGF, and protein expressions of α-SMA and VEGF were all dramatically up-regulated in each group, and were strongly inhibited by SB-431512. TAFs promote the proliferation of OCCs via paracrine and up-regulated expression of angiogenic genes and proteins, which can be effectively inhibited by inhibiting the TGF-β signaling pathway.

Rosenberg EE, Prudnikova TY, Zabarovsky ER, et al.
D-glucuronyl C5-epimerase cell type specifically affects angiogenesis pathway in different prostate cancer cells.
Tumour Biol. 2014; 35(4):3237-45 [PubMed] Related Publications
D-glucuronyl C5-epimerase (GLCE) is involved in breast and lung carcinogenesis as a potential tumor suppressor gene, acting through inhibition of tumor angiogenesis and invasion/metastasis pathways. However, in prostate tumors, increased GLCE expression is associated with advanced disease, suggesting versatile effects of GLCE in different cancers. To investigate further the potential cancer-promoting effect of GLCE in prostate cancer, GLCE was ectopically re-expressed in morphologically different LNCaP and PC3 prostate cancer cells. Transcriptional profiles of normal PNT2 prostate cells, LNCaP, PC3 and DU145 prostate cancer cells, and GLCE-expressing LNCaP and PC3 cells were determined. Comparative analysis revealed the genes whose expression was changed in prostate cancer cells compared with normal PNT2 cells, and those differently expressed between the cancer cell lines (ACTA2, IL6, SERPINE1, TAGLN, SEMA3A, and CDH2). GLCE re-expression influenced mainly angiogenesis-involved genes (ANGPT1, SERPINE1, IGF1, PDGFB, TNF, IL8, TEK, IFNA1, and IFNB1) but in a cell type-specific manner (from basic deregulation of angiogenesis in LNCaP cells to significant activation in PC3 cells). Invasion/metastasis pathway was also affected (MMP1, MMP2, MMP9, S100A4, ITGA1, ITGB3, ERBB2, and FAS). The obtained results suggest activation of angiogenesis as a main molecular mechanism of pro-oncogenic effect of GLCE in prostate cancer. GLCE up-regulation plus expression pattern of a panel of six genes, discriminating morphologically different prostate cancer cell sub-types, is suggested as a potential marker of aggressive prostate cancer.

Herrera A, Herrera M, Alba-Castellón L, et al.
Protumorigenic effects of Snail-expression fibroblasts on colon cancer cells.
Int J Cancer. 2014; 134(12):2984-90 [PubMed] Related Publications
Snail1 is a transcriptional factor that plays an important role in epithelial-mesenchymal transition and in the acquisition of invasive properties by epithelial cells. In colon tumors, Snail1 expression in the stroma correlates with lower specific survival of cancer patients. However, the role(s) of Snail1 expression in stroma and its association with patients' survival have not been determined. We used human primary carcinoma-associated fibroblasts (CAFs) or normal fibroblasts (NFs) and fibroblast cell lines to analyze the effects of Snail1 expression on the protumorigenic capabilities in colon cancer cells. Snail1 expression was higher in CAFs than in NFs and, as well as α-SMA, a classic marker of activated CAFs. Moreover, in tumor samples from 50 colon cancer patients, SNAI1 expression was associated with expression of other CAF markers, such as α-SMA and fibroblast activation protein. Interestingly, coculture of CAFs with colon cells induced a significant increase in epithelial cell migration and proliferation, which was associated with endogenous SNAI1 expression levels. Ectopic manipulation of Snail1 in fibroblasts demonstrated that Snail1 expression controlled migration as well as proliferation of cocultured colon cancer cells in a paracrine manner. Furthermore, expression of Snail1 in fibroblasts was required for the coadjuvant effect of these cells on colon cancer cell growth and invasion when coxenografted in nude mice. Finally, cytokine profile changes, particularly MCP-3 expression, in fibroblasts are put forward as mediators of Snail1-derived effects on colon tumor cell migration. In summary, these studies demonstrate that Snail1 is necessary for the protumorigenic effects of fibroblasts on colon cancer cells.

Sukowati CH, Anfuso B, Torre G, et al.
The expression of CD90/Thy-1 in hepatocellular carcinoma: an in vivo and in vitro study.
PLoS One. 2013; 8(10):e76830 [PubMed] Free Access to Full Article Related Publications
Although the CD90 (Thy-1) was proposed as biomarker of several tumors and cancer stem cells, the involvement of this molecule in the progression of hepatocellular carcinoma (HCC) and other less frequent hepatic neoplasms is still undefined. The distribution of CD90 was investigated both in in vivo (human tissues samples) and in vitro (human HCC cell line JHH-6). A total of 67 liver tumors were analyzed: 51 HCC, 6 cholangiocarcinoma and 10 hepatoblastoma. In all cases, paired tissue sample of both the tumor and cirrhotic liver was available. Hepatic tissue obtained in 12 healthy livers was used as control. CD90 gene expression was studied by RT-qPCR, protein expression was assessed by quantitative Western Blot, immunofluorescence and flow cytometry. The CD90 expression analysis showed a significant increment in tumor compared to both its paired cirrhotic tissue and normal liver (p<0.05 and p<0.001, respectively). This increase was accompanied by the up-regulation of stromal component in the cancer, as demonstrated by alpha smooth muscle actin staining. In vitro analysis of JHH-6 cell line showed a higher proliferation capacity of CD90(+) compared to CD90(-) cells (p<0.001), also noticed in 3D clonogenic assay (p<0.05), associated by a significant higher expression of the promoting factors (hepatocyte growth factor, fibroblast associated protein and alpha smooth muscle actin 2). A higher expression of the breast cancer resistance protein was found in CD90(+) subpopulation while the multidrug resistance protein 1 showed an opposite behavior. Collectively, these results point to the importance of CD90 in the HCC.

Han XY, Wei B, Fang JF, et al.
Epithelial-mesenchymal transition associates with maintenance of stemness in spheroid-derived stem-like colon cancer cells.
PLoS One. 2013; 8(9):e73341 [PubMed] Free Access to Full Article Related Publications
Despite earlier studies demonstrating characteristics of colon cancer stem cells (CCSCs) and the role of epithelial-mesenchymal transition (EMT) in tumor development, it remains controversial as to the relationship between CCSCs and EMT. In this study, in order to present an insight into this relationship in colon cancer, we developed HCT116 and HT29 sphere models, which are known to be the cells enriching cancer stem cells. Compared to their parental counterparts, spheroid cells displayed lower homotypic/heterotypic adhesion but higher in vitro migratory/invasive capacity, as well as higher tumorigenic and metastatic potential in vivo. The spheroid cells also demonstrated down-regulated E-cadherin and up-regulated α-SMA and Vimentin expression, which is the typical phenotype of EMT. In order to explore whether this phenomenon is associated to activation of Wnt/β-catenin pathway, we detected several key signaling molecules. Compared with their parental cells, HCT116 and HT29 spheroid cells demonstrated down-regulated expression of GSK3β, but up-regulated expression of Slug and Snail. And also, the up-regulation of nucleus β-catenin in spheroid cells indicated that the free β-catenin transferred from cytoplasm to cell nucleus. Our findings indicate that spheroid cells have the characteristics of colon cancer stem cells, and EMT may account for their stemness and malignancy. And persistent activation of Wnt/β-catenin pathway may play an important role in the EMT of CCSCs.

Chamney S, McGimpsey S, McConnell V, Willoughby CE
Iris Flocculi as an ocular marker of ACTA2 mutation in familial thoracic aortic aneurysms and dissections.
Ophthalmic Genet. 2015; 36(1):86-8 [PubMed] Related Publications
Non-syndromic familial thoracic aortic aneurysms and dissections (TAAD) are inherited in an autosomal dominant manner. We report a missense mutation in the smooth muscle α-actin (ACTA2; MIM*102620) gene in a 3 generational family from Northern Ireland in which iris flocculi were an ocular marker of the disease.

Lee HW, Park YM, Lee SJ, et al.
Alpha-smooth muscle actin (ACTA2) is required for metastatic potential of human lung adenocarcinoma.
Clin Cancer Res. 2013; 19(21):5879-89 [PubMed] Related Publications
PURPOSE: Metastatic relapse of primary lung cancer leads to therapeutic resistance and unfavorable clinical prognosis; therefore, identification of key molecules associated with metastatic conversion has significant clinical implications. We previously identified a link between early brain metastasis of lung adenocarcinoma and amplification of the α-smooth muscle actin (ACTA2) gene. The aim of present study was to investigate the prognostic and functional significance of ACTA2 expression in cancer cells for the metastatic potential of lung adenocarcinomas.
EXPERIMENTAL DESIGN: ACTA2 expression was analyzed in tumor cells from 263 patients with primary lung adenocarcinomas by immunohistochemistry, and was correlated with clinicopathologic parameters. The expression of ACTA2 in human lung adenocarcinoma cells was modulated with short hairpin RNAs (shRNA) and siRNAs specifically targeting ACTA2.
RESULTS: The patients with lung adenocarcinomas with high ACTA2 expression in tumor cells showed significantly enhanced distant metastasis and unfavorable prognosis. ACTA2 downregulation remarkably impaired in vitro migration, invasion, clonogenicity, and transendothelial penetration of lung adenocarcinoma cells without affecting proliferation. Consistent with the in vitro results, depletion of ACTA2 in human lung adenocarcinoma PC14PE6 cells significantly reduced their metastatic potential without altering their tumorigenic potential. Expression of c-MET and FAK in lung adenocarcinoma cells was also reduced by ACTA2-targeting siRNAs and shRNAs, and was accompanied by a loss of mesenchymal characteristics.
CONCLUSIONS: These findings indicate that ACTA2 regulates c-MET and FAK expression in lung adenocarcinoma cells, which positively and selectively influence metastatic potential. Therefore, ACTA2 could be a promising prognostic biomarker and/or therapeutic target for metastatic lung adenocarcinoma.

Moon H, Lee CS, Inder KL, et al.
PTRF/cavin-1 neutralizes non-caveolar caveolin-1 microdomains in prostate cancer.
Oncogene. 2014; 33(27):3561-70 [PubMed] Related Publications
Caveolin-1 has a complex role in prostate cancer and has been suggested to be a potential biomarker and therapeutic target. As mature caveolin-1 resides in caveolae, invaginated lipid raft domains at the plasma membrane, caveolae have been suggested as a tumor-promoting signaling platform in prostate cancer. However, caveola formation requires both caveolin-1 and cavin-1 (also known as PTRF; polymerase I and transcript release factor). Here, we examined the expression of cavin-1 in prostate epithelia and stroma using tissue microarray including normal, non-malignant and malignant prostate tissues. We found that caveolin-1 was induced without the presence of cavin-1 in advanced prostate carcinoma, an expression pattern mirrored in the PC-3 cell line. In contrast, normal prostate epithelia expressed neither caveolin-1 nor cavin-1, while prostate stroma highly expressed both caveolin-1 and cavin-1. Utilizing PC-3 cells as a suitable model for caveolin-1-positive advanced prostate cancer, we found that cavin-1 expression in PC-3 cells inhibits anchorage-independent growth, and reduces in vivo tumor growth and metastasis in an orthotopic prostate cancer xenograft mouse model. The expression of α-smooth muscle actin in stroma along with interleukin-6 (IL-6) in cancer cells was also decreased in tumors of mice bearing PC-3-cavin-1 tumor cells. To determine whether cavin-1 acts by neutralizing caveolin-1, we expressed cavin-1 in caveolin-1-negative prostate cancer LNCaP and 22Rv1 cells. Caveolin-1 but not cavin-1 expression increased anchorage-independent growth in LNCaP and 22Rv1 cells. Cavin-1 co-expression reversed caveolin-1 effects in caveolin-1-positive LNCaP cells. Taken together, these results suggest that caveolin-1 in advanced prostate cancer is present outside of caveolae, because of the lack of cavin-1 expression. Cavin-1 expression attenuates the effects of non-caveolar caveolin-1 microdomains partly via reduced IL-6 microenvironmental function. With circulating caveolin-1 as a potential biomarker for advanced prostate cancer, identification of the molecular pathways affected by cavin-1 could provide novel therapeutic targets.

Wang C, Jin MS, Zou YB, et al.
Diagnostic significance of DOG-1 and PKC-θ expression and c-Kit/PDGFRA mutations in gastrointestinal stromal tumours.
Scand J Gastroenterol. 2013; 48(9):1055-65 [PubMed] Related Publications
OBJECTIVE: To investigate discovered on gastrointestinal stromal tumor (GIST)-1 (DOG-1) and protein kinase C-θ (PKC-θ) expression in a series of GISTs and determine the sensitivity, specificity, and diagnostic value of these two antigens.
METHODS: Immnunohistochemistry (IHC) was used to detect CD117, DOG-1, PKC-θ, CD34, Ki-67, α-smooth muscle actin (SMA), S100, and Desmin expression in 147 GISTs and 51 non-GISTs. c-Kit gene (exons 9, 11, 13, and 17) and platelet-derived growth factor receptor-alpha (PDGFRA) gene (exons 12 and 18) mutations were also detected.
RESULTS: About 94.5% GISTs were CD117 positive, 96% were DOG-1 positive, and 90.5% were PKC-θ positive. DOG-1 had a specificity of 100%, while CD117 and PKC-θ had a specificity of 90% and 80%, respectively. There was no significant difference between DOG-1 and PKC-θ expressions when compared to CD117 expression. In 30 out of 42 (71.5%) GISTs, a c-Kit gene mutation was found, and in 3 out of 42 cases (7%), PDGFRA was mutated. Wild-type c-Kit/PDGFRA genes accounted for 21.5% (9/42). Most c-Kit gene mutations were found to be located at exon 11, mainly as in-frame deletions. Mutations in exon 9 were all missense mutations. Most PDGFRA gene mutations were found in exon 18, codon 842. c-Kit gene mutations in exons 13 and 17, and the PDGFRA gene mutation in exon 12 were not detected.
CONCLUSIONS: Compared to CD117, DOG-1 is a biomarker with higher sensitivity and specificity. The combination of CD117 and DOG-1 can be used to improve the diagnosis of GIST. Although PKC-θ has a lower specificity than DOG-1, it can be a useful biomarker, especially in CD117(-) and/or DOG-1(-) cases.

Berndt SI, Skibola CF, Joseph V, et al.
Genome-wide association study identifies multiple risk loci for chronic lymphocytic leukemia.
Nat Genet. 2013; 45(8):868-76 [PubMed] Free Access to Full Article Related Publications
Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P=1.22×10(-14)), 18q21.33 (BCL2, P=7.76×10(-11)), 11p15.5 (C11orf21, P=2.15×10(-10)), 4q25 (LEF1, P=4.24×10(-10)), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P=2.50×10(-9)), 9p21.3 (CDKN2B-AS1, P=1.27×10(-8)), 18q21.32 (PMAIP1, P=2.51×10(-8)), 15q15.1 (BMF, P=2.71×10(-10)) and 2p22.2 (QPCT, P=1.68×10(-8)), as well as an independent signal at an established locus (2q13, ACOXL, P=2.08×10(-18)). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P=5.40×10(-8)) and 5p15.33 (TERT, P=1.92×10(-7)). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.

Bahrami A, Perez-Ordonez B, Dalton JD, Weinreb I
An analysis of PLAG1 and HMGA2 rearrangements in salivary duct carcinoma and examination of the role of precursor lesions.
Histopathology. 2013; 63(2):250-62 [PubMed] Related Publications
AIMS: Salivary duct carcinoma (SDC) often arises in pleomorphic adenoma (PA). Putative precursors, including low-grade cribriform cystadenocarcinoma (LGCCC) and ductal carcinoma in-situ (DCIS), are more controversial. Rearrangement of PLAG1 or HMGA2 is seen in 50-70% of PAs, but this has not been investigated in SDC. Using a large collection of SDCs from a single institution, we aimed to study these genes by fluorescence in-situ hybridization (FISH), and to correlate the presence of precursor lesions/intraductal proliferations with gene alterations.
METHODS AND RESULTS: Forty-four SDCs were stained for smooth muscle actin, CK14, and p63, and examined with PLAG1 and HMGA2 FISH. Eight cases were SDC ex-PA; ten had a hyalinized nodule (HN), which is suspicious for PA; six arose in association with LGCCC; and twenty were 'de-novo' SDCs. Ten cases had PLAG1 rearrangement/amplification (22.7%) and eight had HMGA2 (18.2%) rearrangement/amplification. The positive cases were four SDC ex-PAs, eight SDCs with an HN, and five 'de-novo' SDCs. Twenty-three SDC ex-PAs were present in total (52.3%). All six SDC ex-LGCCCs were FISH-negative. Myoepithelial staining surrounded all LGCCCs, and demonstrated DCIS in 17 cases. Eleven DCIS lesions were in SDC ex-PAs or FISH-positive 'de-novo' SDCs. These cases represent 'cancerization' of ducts. Only six FISH-negative 'de-novo' SDCs showed DCIS.
CONCLUSIONS: A large proportion of SDCs arise in PAs (with or without residual evidence of a PA). A small proportion of SDCs arise in LGCCCs. Cases showing DCIS often represent cancerization.

Hendrayani SF, Al-Khalaf HH, Aboussekhra A
Curcumin triggers p16-dependent senescence in active breast cancer-associated fibroblasts and suppresses their paracrine procarcinogenic effects.
Neoplasia. 2013; 15(6):631-40 [PubMed] Free Access to Full Article Related Publications
Activated cancer-associated fibroblasts (CAFs) or myofibroblasts not only facilitate tumor growth and spread but also affect tumor response to therapeutic agents. Therefore, it became clear that efficient therapeutic regimens should also take into account the presence of these supportive cells and inhibit their paracrine effects. To this end, we tested the effect of low concentrations of curcumin, a pharmacologically safe natural product, on patient-derived primary breast CAF cells. We have shown that curcumin treatment upregulates p16(INK4A) and other tumor suppressor proteins while inactivates the JAK2/STAT3 pathway. This reduced the level of alpha-smooth muscle actin (α-SMA) and the migration/invasion abilities of these cells. Furthermore, curcumin suppressed the expression/secretion of stromal cell-derived factor-1 (SDF-1), interleukin-6 (IL-6), matrix metalloproteinase-2 (MMP-2), MMP-9, and transforming growth factor-β, which impeded their paracrine procarcinogenic potential. Intriguingly, these effects were sustained even after curcumin withdrawal and cell splitting. Therefore, using different markers of senescence [senescence-associated β-galactosidase (SA-β-gal) activity, Ki-67 and Lamin B1 levels, and bromodeoxyuridine incorporation], we have shown that curcumin markedly suppresses Lamin B1 and triggers DNA damage-independent senescence in proliferating but not quiescent breast stromal fibroblasts. Importantly, this curcumin-related senescence was p16(INK4A)-dependent and occurred with no associated inflammatory secretory phenotype. These results indicate the possible inactivation of cancer-associated myofibroblasts and present the first indication that curcumin can trigger DNA damage-independent and safe senescence in stromal fibroblasts.

Liang S, Cuevas G, Tizani S, et al.
Novel mechanism of regulation of fibrosis in kidney tumor with tuberous sclerosis.
Mol Cancer. 2013; 12:49 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Deficiency in tuberin results in activation the mTOR pathway and leads to accumulation of cell matrix proteins. The mechanisms by which tuberin regulates fibrosis in kidney angiomyolipomas (AMLs) of tuberous sclerosis patients are not fully known.
METHOD: In the present study, we investigated the potential role of tuberin/mTOR pathway in the regulation of cell fibrosis in AML cells and kidney tumor tissue from tuberous sclerosis complex (TSC) patients.
RESULTS: AML cells treated with rapamycin shows a significant decrease in mRNA and protein expression as well as in promoter transcriptional activity of alpha-smooth muscle actin (α-SMA) compared to untreated cells. In addition, cells treated with rapamycin significantly decreased the protein expression of the transcription factor YY1. Rapamycin treatment also results in the redistribution of YY1 from the nucleus to cytoplasm in AML cells. Moreover, cells treated with rapamycin resulted in a significant reduce of binding of YY1 to the αSMA promoter element in nuclear extracts of AML cells. Kidney angiomyolipoma tissues from TSC patients showed lower levels of tuberin and higher levels of phospho-p70S6K that resulted in higher levels of mRNA and protein of αSMA expression compared to control kidney tissues. In addition, most of the α-SMA staining was identified in the smooth muscle cells of AML tissues. YY1 was also significantly increased in tumor tissue of AMLs compared to control kidney tissue suggesting that YY1 plays a major role in the regulation of αSMA.
CONCLUSIONS: These data comprise the first report to provide one mechanism whereby rapamycin might inhibit the cell fibrosis in kidney tumor of TSC patients.

Pinchuk IV, Morris KT, Nofchissey RA, et al.
Stromal cells induce Th17 during Helicobacter pylori infection and in the gastric tumor microenvironment.
PLoS One. 2013; 8(1):e53798 [PubMed] Free Access to Full Article Related Publications
Gastric cancer is associated with chronic inflammation and Helicobacter pylori infection. Th17 cells are CD4(+) T cells associated with infections and inflammation; but their role and mechanism of induction during carcinogenesis is not understood. Gastric myofibroblasts/fibroblasts (GMF) are abundant class II MHC expressing cells that act as novel antigen presenting cells. Here we have demonstrated the accumulation of Th17 in H. pylori-infected human tissues and in the gastric tumor microenvironment. GMF isolated from human gastric cancer and H. pylori infected tissues co-cultured with CD4(+) T cells induced substantially higher levels of Th17 than GMF from normal tissues in an IL-6, TGF-β, and IL-21 dependent manner. Th17 required interaction with class II MHC on GMF for activation and proliferation. These studies suggest that Th17 are induced during both H. pylori infection and gastric cancer in the inflammatory milieu of gastric stroma and may be an important link between inflammation and carcinogenesis.

Yang X, Li S, Li W, et al.
Inactivation of lysyl oxidase by β-aminopropionitrile inhibits hypoxia-induced invasion and migration of cervical cancer cells.
Oncol Rep. 2013; 29(2):541-8 [PubMed] Related Publications
Tumor invasion and migration are major causes of mortality in patients with cervical carcinoma. Tumors under hypoxic conditions are more invasive and have a higher metastasic activity. Lysyl oxidase (LOX) is a hypoxia-responsive gene. LOX has been shown to be essential for hypoxia-induced metastasis in breast cancer. However, the direct impact of LOX on cervical cancer cell motility remains poorly understood. Our study revealed that LOX expression at protein and catalytic levels is upregulated in cervical cancer cells upon exposure to hypoxia. Hypoxia induced mesenchymal-like morphological changes in HeLa and SiHa cells which were accompanied by upregulation of α-SMA and vimentin, two mesenchymal markers, and downregulation of E-cadherin, an epithelial marker, indicating the epithelial-mesenchymal transition (EMT) of cervical cancer cells occurred under hypoxic conditions. Treatment of tumor cells with β-aminopropionitrile (BAPN), an active site inhibitor of LOX, blocked the hypoxia-induced EMT morphological and marker protein changes, and inhibited invasion and migration capacities of cervical carcinoma cells in vitro. Collectively, these findings suggest LOX enhances hypoxia-induced invasion and migration in cervical cancer cells mediated by the EMT which can be inhibited by BAPN.

Kabashima-Niibe A, Higuchi H, Takaishi H, et al.
Mesenchymal stem cells regulate epithelial-mesenchymal transition and tumor progression of pancreatic cancer cells.
Cancer Sci. 2013; 104(2):157-64 [PubMed] Related Publications
Cancer-associated fibroblasts contribute to cancer progression that is caused by epithelial-mesenchymal transition (EMT). Recently, mesenchymal stem cells (MSCs) were found to be the major candidate involved in the development of tumor-promoting cancer stroma. Here we report that α-smooth muscle actin-positive myofibroblast-like cells originating from MSCs contribute to inducing EMT in side population cells of pancreatic cancer. More importantly, MSC-derived myofibroblasts function to maintain tumor-initiating stem cell-like characteristics, including augmenting expression levels of various stemness-associated genes, enhancing sphere- forming activity, promoting tumor formation in a mouse xenograft model, and showing resistance to anticancer drugs. Furthermore, both γ-secretase inhibitor and siRNA directed against Jagged-1 attenuated MSC-associated E-cadherin suppression and sphere formation in pancreatic cancer side population cells. Thus, our results suggest that MSC-derived myofibroblasts play important roles in regulating EMT and tumor-initiating stem cell-like properties of pancreatic cancer cells through an intermediating Notch signal.

Lee HW, Seol HJ, Choi YL, et al.
Genomic copy number alterations associated with the early brain metastasis of non-small cell lung cancer.
Int J Oncol. 2012; 41(6):2013-20 [PubMed] Related Publications
Frequent early development of systemic metastasis leads to unfavourable clinical prognosis of non-small cell lung cancer (NSCLC). Although brain metastasis (BM) contributes significantly to morbidity and mortality of NSCLC, relevant driver mechanisms are largely unknown. To elucidate genetic alterations associated with early BM of NSCLC, we retrospectively collected 18 NSCLC cases with BM [12 adenocarcinomas (ADC) and 6 squamous cell carcinomas (SQCC)] whose surgical tissues of both primary and brain metastatic tumors were preserved as formaldehyde-fixed and paraffin-embedded (FFPE) pathological samples. When chromosomal copy number alterations (CNA) of those FFPE samples were analysed by the Molecular Inversion Probe (MIP) technology, the most frequent CNAs detected in primary lung ADCs were gains of 3q, 5p, 5q, 6p, 8q, 9p, 11p, 15q, 17q and losses of 10q and 22q whereas primary lung SQCCs revealed gains in 4q and 12q and loss in 9q. In particular, when comparative MIP was performed in primary 12 ADCs depending on the pattern of BM to uncover predetermining signatures that can predict the risk of BM, selectively amplified regions of primary lung ADCs (5q35, 10q23 and 17q23-24) were identified as significantly associated with the development of early BM within 3 months after first diagnosis of primary tumors. Those regions harbour several candidate genes including NeurL1B, ACTA2, FAS and ICAM2. Although more validation is needed, the genetic signatures elucidated in this study help to identify useful molecular markers defining an NSCLC patient subgroup at risk of early BM, guiding therapeutic decisions.

Do EK, Kim YM, Heo SC, et al.
Lysophosphatidic acid-induced ADAM12 expression mediates human adipose tissue-derived mesenchymal stem cell-stimulated tumor growth.
Int J Biochem Cell Biol. 2012; 44(11):2069-76 [PubMed] Related Publications
Lysophosphatidic acid (LPA) is involved in mesenchymal stem cell-stimulated tumor growth in vivo. However, the molecular mechanism by which mesenchymal stem cells promote tumorigenesis remains elusive. In the present study, we demonstrate that conditioned medium from A549 human lung adenocarcinoma cells (A549 CM) induced the expression of ADAM12, a disintegrin and metalloproteases family member, in human adipose tissue-derived mesenchymal stem cells (hASCs). A549 CM-stimulated ADAM12 expression was abrogated by pretreatment of hASCs with the LPA receptor 1 inhibitor Ki16425 or by small interfering RNA-mediated silencing of LPA receptor 1, suggesting a key role for the LPA-LPA receptor 1 signaling axis in A549 CM-stimulated ADAM12 expression. Silencing of ADAM12 expression using small interfering RNA or short hairpin RNA abrogated LPA-induced expression of both α-smooth muscle actin, a marker of carcinoma-associated fibroblasts, and ADAM12 in hASCs. Using a xenograft transplantation model of A549 cells, we demonstrated that silencing of ADAM12 inhibited the hASC-stimulated in vivo growth of A549 xenograft tumors and the differentiation of transplanted hASCs to α-smooth muscle actin-positive carcinoma-associated fibroblasts. LPA-conditioned medium from hASCs induced the adhesion of A549 cells and silencing of ADAM12 inhibited LPA-induced expression of extracellular matrix proteins, periostin and βig-h3, in hASCs and LPA-conditioned medium-stimulated adhesion of A549 cells. These results suggest a pivotal role for LPA-stimulated ADAM12 expression in tumor growth and the differentiation of hASCs to carcinoma-associated fibroblasts expressing α-smooth muscle actin, periostin, and βig-h3.

Al-Ansari MM, Hendrayani SF, Shehata AI, Aboussekhra A
p16(INK4A) represses the paracrine tumor-promoting effects of breast stromal fibroblasts.
Oncogene. 2013; 32(18):2356-64 [PubMed] Free Access to Full Article Related Publications
Cancer-associated fibroblasts (CAFs), the most abundant and probably the most active cellular component of breast cancer-associated stroma, promote carcinogenesis through paracrine effects; however, the molecular basis remains elusive. We have shown here that p16(INK4A) expression is reduced in 83% CAFs as compared with their normal adjacent counterparts cancer-free tissues isolated from the same patients. This decrease is mainly due to AUF1-dependent higher turnover of the CDKN2A mRNA in CAFs. Importantly, p16(INK4A) downregulation using specific siRNA activated breast fibroblasts and increased the expression/secretion levels of stromal cell-derived factor 1 (SDF-1) and matrix metalloproteinase (MMP)-2. Consequently, media conditioned with these cells stimulated the proliferation of epithelial cells. Furthermore, the migration/invasion of breast cancer cells was also enhanced in an SDF-1-dependent manner. This effect was mediated through inducing an epithelial-mesenchymal transition state. By contrast, increase in p16(INK4A) level through ectopic expression or AUF1 downregulation, reduced the secreted levels of SDF-1 and MMP-2 and suppressed the pro-carcinogenic effects of CAFs. In addition, p16(INK4A)-defective fibroblasts accelerated breast tumor xenograft formation and growth rate in mice. Importantly, tumors formed in the presence of p16(INK4A)-defective fibroblasts exhibited higher levels of active Akt, Cox-2, MMP-2 and MMP-9, showing their greater aggressiveness as compared with xenografts formed in the presence of p16(INK4A)-proficient fibroblasts. These results provide the first indication that p16(INK4A) downregulation in breast stromal fibroblasts is an important step toward their activation.

Han M, Wang Y, Liu M, et al.
MiR-21 regulates epithelial-mesenchymal transition phenotype and hypoxia-inducible factor-1α expression in third-sphere forming breast cancer stem cell-like cells.
Cancer Sci. 2012; 103(6):1058-64 [PubMed] Related Publications
Cancer stem cells (CSCs) are predicted to be critical drivers of tumor progression due to their "stemness", but the molecular mechanism of CSCs in regulating metastasis remains to be elucidated. Epithelial-mesenchymal transition (EMT), hypoxia-inducible factor (HIF)-1α, and miR-21, all of which contribute to cell migration for metastasis, are interrelated with CSCs. In the present study, third-sphere forming (3-S) CSC-like cells, which showed elevated CSC surface markers (ALDH1(+) and CD44(+)/CD24(-/low)) and sphereforming capacity as well as migration and invasion capacities, were cultured and isolated from breast cancer MCF-7 parental cells, to evaluate the role of miR-21 in regulating the CSC-like cell biological features, especially EMT. EMT, which was assessed by overexpression of mesenchymal cell markers (N-cadherin, Vimentin, alpha-smooth muscle actin [α-SMA]) and suppression of epithelial cell marker (E-cadherin), was induced in 3-S CSC-like cells. Moreover, both of HIF-1α and miR-21 were upregulated in the CSC-like cells. Interestingly, antagonism of miR-21 by antagomir led to reversal of EMT, downexpression of HIF-1α, as well as suppression of invasion and migration, which indicates a key role of miR-21 involved in regulate CSC-associated features. In conclusion, we demonstrated that the formation of CSC-like cells undergoing process of EMT-like associated with overexpression of HIF-1α, both of which are regulated by miR-21.

Okabe H, Beppu T, Ueda M, et al.
Identification of CXCL5/ENA-78 as a factor involved in the interaction between cholangiocarcinoma cells and cancer-associated fibroblasts.
Int J Cancer. 2012; 131(10):2234-41 [PubMed] Related Publications
Knowledge of tumor-stromal interactions is essential for understanding tumor development. We focused on the interaction between cholangiocarcinoma and cancer-associated fibroblasts (CAFs) in intrahepatic cholangiocarcinoma and reported their positive interaction in vitro and in vivo. The aim of this study is to identify the key protein involved in the interaction between cholangiocarcinoma cells and CAFs and its role on cholangiocarcinoma progression. Using the conditioning medium from cholangiocarcinoma cells, hepatic stellate cells and coculture of them, Protein-Chip analysis with SELDI-TOF-MS showed that the peak of an 8,360-Da protein remarkably increased in the coculture medium. This protein was identified as CXCL5/ENA78, epithelial cell-derived neutrophil-activating peptide-78, by q-TOF/MS/MS analysis. Two cholangiocarcinoma cell lines, HuCCT1 and RBE, produced CXCL5 that promoted their invasion and migration in an autocrine fashion. These effects of CXCL5 significantly decreased by inhibition of CXC-receptor 2, which is the receptor for CXCL5. In addition, IL-1β produced by hepatic stellate cells induced the expression of CXCL5 in cholangiocarcinoma cells. In human tissue samples, a significant correlation was observed between CAFs and CXCL5 produced by cholangiocarcinoma cells in intrahepatic cholangiocarcinoma (p = 0.0044). Furthermore, the high-CXCL5-expression group exhibited poor overall survival after curative hepatic resection (p = 0.027). The presence of tumor-infiltrating neutrophils expressing CD66b was associated with CXCL5 expression in tumor cells (p < 0.0001). These data suggest that CXCL5 is important for the interaction between cholangiocarcinoma and CAFs, and inhibition of tumor-stromal interactions may be a useful therapeutic approach for cholangiocarcinoma.

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