GUSB

Gene Summary

Gene:GUSB; glucuronidase, beta
Aliases: BG, MPS7
Location:7q21.11
Summary:This gene encodes a hydrolase that degrades glycosaminoglycans, including heparan sulfate, dermatan sulfate, and chondroitin-4,6-sulfate. The enzyme forms a homotetramer that is localized to the lysosome. Mutations in this gene result in mucopolysaccharidosis type VII. Alternative splicing results in multiple transcript variants. There are many pseudogenes of this locus in the human genome.[provided by RefSeq, May 2014]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:beta-glucuronidase
HPRD
Source:NCBIAccessed: 27 February, 2015

Ontology:

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 28 February 2015 using data from PubMed using criteria.

Literature Analysis

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

Latest Publications: GUSB (cancer-related)

Konecny GE, Wang C, Hamidi H, et al.
Prognostic and therapeutic relevance of molecular subtypes in high-grade serous ovarian cancer.
J Natl Cancer Inst. 2014; 106(10) [PubMed] Article available free on PMC after 01/10/2015 Related Publications
Molecular classification of high-grade serous ovarian cancer (HGSOC) using transcriptional profiling has proven to be complex and difficult to validate across studies. We determined gene expression profiles of 174 well-annotated HGSOCs and demonstrate prognostic significance of the prespecified TCGA Network gene signatures. Furthermore, we confirm the presence of four HGSOC transcriptional subtypes using a de novo classification. Survival differed statistically significantly between de novo subtypes (log rank, P = .006) and was the best for the immunoreactive-like subtype, but statistically significantly worse for the proliferative- or mesenchymal-like subtypes (adjusted hazard ratio = 1.89, 95% confidence interval = 1.18 to 3.02, P = .008, and adjusted hazard ratio = 2.45, 95% confidence interval = 1.43 to 4.18, P = .001, respectively). More prognostic information was provided by the de novo than the TCGA classification (Likelihood Ratio tests, P = .003 and P = .04, respectively). All statistical tests were two-sided. These findings were replicated in an external data set of 185 HGSOCs and confirm the presence of four prognostically relevant molecular subtypes that have the potential to guide therapy decisions.

Schroeder MP, Rubio-Perez C, Tamborero D, et al.
OncodriveROLE classifies cancer driver genes in loss of function and activating mode of action.
Bioinformatics. 2014; 30(17):i549-55 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
MOTIVATION: Several computational methods have been developed to identify cancer drivers genes-genes responsible for cancer development upon specific alterations. These alterations can cause the loss of function (LoF) of the gene product, for instance, in tumor suppressors, or increase or change its activity or function, if it is an oncogene. Distinguishing between these two classes is important to understand tumorigenesis in patients and has implications for therapy decision making. Here, we assess the capacity of multiple gene features related to the pattern of genomic alterations across tumors to distinguish between activating and LoF cancer genes, and we present an automated approach to aid the classification of novel cancer drivers according to their role.
RESULT: OncodriveROLE is a machine learning-based approach that classifies driver genes according to their role, using several properties related to the pattern of alterations across tumors. The method shows an accuracy of 0.93 and Matthew's correlation coefficient of 0.84 classifying genes in the Cancer Gene Census. The OncodriveROLE classifier, its results when applied to two lists of predicted cancer drivers and TCGA-derived mutation and copy number features used by the classifier are available at http://bg.upf.edu/oncodrive-role.
AVAILABILITY AND IMPLEMENTATION: The R implementation of the OncodriveROLE classifier is available at http://bg.upf.edu/oncodrive-role.
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Molinari F, Signoroni S, Lampis A, et al.
BRAF mutation analysis is a valid tool to implement in Lynch syndrome diagnosis in patients classified according to the Bethesda guidelines.
Tumori. 2014 May-Jun; 100(3):315-20 [PubMed] Related Publications
AIMS AND BACKGROUND: Lynch syndrome (LS) is clinically defined by the Amsterdam criteria (AC) and by germline mutations in mismatch-repair (MMR) genes leading to microsatellite instability (MSI) at the molecular level. Patients who do not fulfil AC are considered suspected-Lynch according to the less stringent Bethesda guidelines (BG) and should be tested for MSI and MMR germline mutations. BRAF mutations have been proposed as a marker to exclude LS because they are generally absent in LS patients and present in sporadic colorectal cancer (sCRC) with MSI due to promoter hypermethylation of the MLH1 gene. Our aim was to verify whether BRAF mutations may improve the criteria to select patients for germline MMR mutation assessment.
MATERIAL AND METHODS: We analyzed 303 formalin-fixed paraffin-embedded CRC samples including 174 sCRC, 28 patients fulfilling AC, and 101 suspected-Lynch patients fulfilling BG. We analyzed MSI and BRAF mutations in all CRC samples. MLH1, MSH2 and MSH6 germline mutations were investigated in MSI patients fulfilling AC or BG.
RESULTS: sCRC samples showed MSI in 20/174 (11%) cases. BRAF mutations were detected in 10/174 (6%) sCRC cases and were significantly correlated with MSI (P = 0.002). MSI was observed in 24/28 (86%) Amsterdam cases which were BRAF wild-type. MMR gene mutation was detected in 22/26 (85%) AC cases, all showing MSI. Suspected-Lynch cases carried MSI in 41/101 (40%) and BRAF mutations in 7/101 (7%) cases. MMR gene mutation was detected in 13/28 (46%) evaluable MSI patients of this group and only in cases characterized by a wild-type BRAF gene.
CONCLUSIONS: The prevalence of BRAF mutations in CRC patients is not high but extremely correlated with MSI and risk categories as BG, whereas they are absent in LS patients. BRAF mutation detection can reduce the need for MMR gene analysis in a small (but not negligible) proportion of MSI patients (7%), with a positive impact on the financial and psychological costs of unnecessary tests.

Milinkovic VP, Skender Gazibara MK, Manojlovic Gacic EM, et al.
The impact of TP53 and RAS mutations on cerebellar glioblastomas.
Exp Mol Pathol. 2014; 97(2):202-7 [PubMed] Related Publications
Cerebellar glioblastoma (cGBM) is a rare, inadequately characterized disease, without detailed information on its molecular basis. This is the first report analyzing both TP53 and RAS alterations in cGBM. TP53 mutations were detected in more than half of the samples from our cohort, mainly in hotspot codons. There were no activating mutations in hotspot codons 12/13 and 61 of KRAS and HRAS genes in cGBM samples but we detected alterations in other parts of exons 2 and 3 of these genes, including premature induction of STOP codon. This mutation was present in 3 out of 5 patients. High incidence of RAS mutations, as well as significantly longer survival of cGBM patients compared to those with supratentorial GBM suggest that cGBM may have different mechanisms of occurrence. Our results suggest that inactivation of TP53 and RAS may play an important role in the progression of cerebellar GBM.

Milosevic Z, Pesic M, Stankovic T, et al.
Targeting RAS-MAPK-ERK and PI3K-AKT-mTOR signal transduction pathways to chemosensitize anaplastic thyroid carcinoma.
Transl Res. 2014; 164(5):411-23 [PubMed] Related Publications
Anaplastic thyroid carcinoma (ATC) is a rare, but aggressive and chemoresistant tumor with dismal prognosis. Most ATCs harbor mutations that activate RAS/MAPK/ERK and PI3K/AKT/mTOR pathways. Therefore, we investigated and correlated the expression of phosphatase and tensin homolog, pERK, and pAKT proteins as well as mutations of BRAF, RAS, and p53 genes in samples of patients with ATC. Furthermore, we evaluated the potential of inhibition of these pathways on chemosensitization of ATC using 2 thyroid carcinoma cell lines (FRO and SW1736). Our results revealed a negative correlation between the activity of RAS-MAPK-ERK and PI3K-AKT-mTOR pathways in samples of patients. To be specific, the PI3K-AKT-mTOR pathway was suppressed in patients with activated NRAS or high pERK expression. In vitro results suggest that the inhibition of either RAS-MAPK-ERK or PI3K-AKT-mTOR components may confer sensitivity of thyroid cancer cells to classic chemotherapeutics. This may form a basis for the development of novel genetic-based therapeutic approach for this cancer type.

Hedditch EL, Gao B, Russell AJ, et al.
ABCA transporter gene expression and poor outcome in epithelial ovarian cancer.
J Natl Cancer Inst. 2014; 106(7) [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: ATP-binding cassette (ABC) transporters play various roles in cancer biology and drug resistance, but their association with outcomes in serous epithelial ovarian cancer (EOC) is unknown.
METHODS: The relationship between clinical outcomes and ABC transporter gene expression in two independent cohorts of high-grade serous EOC tumors was assessed with real-time quantitative polymerase chain reaction, analysis of expression microarray data, and immunohistochemistry. Associations between clinical outcomes and ABCA transporter gene single nucleotide polymorphisms were tested in a genome-wide association study. Impact of short interfering RNA-mediated gene suppression was determined by colony forming and migration assays. Association with survival was assessed with Kaplan-Meier analysis and log-rank tests. All statistical tests were two-sided.
RESULTS: Associations with outcome were observed with ABC transporters of the "A" subfamily, but not with multidrug transporters. High-level expression of ABCA1, ABCA6, ABCA8, and ABCA9 in primary tumors was statistically significantly associated with reduced survival in serous ovarian cancer patients. Low levels of ABCA5 and the C-allele of rs536009 were associated with shorter overall survival (hazard ratio for death = 1.50; 95% confidence interval [CI] =1.26 to 1.79; P = 6.5e-6). The combined expression pattern of ABCA1, ABCA5, and either ABCA8 or ABCA9 was associated with particularly poor outcome (mean overall survival in group with adverse ABCA1, ABCA5 and ABCA9 gene expression = 33.2 months, 95% CI = 26.4 to 40.1; vs 55.3 months in the group with favorable ABCA gene expression, 95% CI = 49.8 to 60.8; P = .001), independently of tumor stage or surgical debulking status. Suppression of cholesterol transporter ABCA1 inhibited ovarian cancer cell growth and migration in vitro, and statin treatment reduced ovarian cancer cell migration.
CONCLUSIONS: Expression of ABCA transporters was associated with poor outcome in serous ovarian cancer, implicating lipid trafficking as a potentially important process in EOC.

Woditschka S, Evans L, Duchnowska R, et al.
DNA double-strand break repair genes and oxidative damage in brain metastasis of breast cancer.
J Natl Cancer Inst. 2014; 106(7) [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: Breast cancer frequently metastasizes to the brain, colonizing a neuro-inflammatory microenvironment. The molecular pathways facilitating this colonization remain poorly understood.
METHODS: Expression profiling of 23 matched sets of human resected brain metastases and primary breast tumors by two-sided paired t test was performed to identify brain metastasis-specific genes. The implicated DNA repair genes BARD1 and RAD51 were modulated in human (MDA-MB-231-BR) and murine (4T1-BR) brain-tropic breast cancer cell lines by lentiviral transduction of cDNA or short hairpin RNA (shRNA) coding sequences. Their functional contribution to brain metastasis development was evaluated in mouse xenograft models (n = 10 mice per group).
RESULTS: Human brain metastases overexpressed BARD1 and RAD51 compared with either matched primary tumors (1.74-fold, P < .001; 1.46-fold, P < .001, respectively) or unlinked systemic metastases (1.49-fold, P = .01; 1.44-fold, P = .008, respectively). Overexpression of either gene in MDA-MB-231-BR cells increased brain metastases by threefold to fourfold after intracardiac injections, but not lung metastases upon tail-vein injections. In 4T1-BR cells, shRNA-mediated RAD51 knockdown reduced brain metastases by 2.5-fold without affecting lung metastasis development. In vitro, BARD1- and RAD51-overexpressing cells showed reduced genomic instability but only exhibited growth and colonization phenotypes upon DNA damage induction. Reactive oxygen species were present in tumor cells and elevated in the metastatic neuro-inflammatory microenvironment and could provide an endogenous source of genotoxic stress. Tempol, a brain-permeable oxygen radical scavenger suppressed brain metastasis promotion induced by BARD1 and RAD51 overexpression.
CONCLUSIONS: BARD1 and RAD51 are frequently overexpressed in brain metastases from breast cancer and may constitute a mechanism to overcome reactive oxygen species-mediated genotoxic stress in the metastatic brain.

Krzystek-Korpacka M, Diakowska D, Bania J, Gamian A
Expression stability of common housekeeping genes is differently affected by bowel inflammation and cancer: implications for finding suitable normalizers for inflammatory bowel disease studies.
Inflamm Bowel Dis. 2014; 20(7):1147-56 [PubMed] Related Publications
Instability of housekeeping genes (HKG), supposedly unregulated and hence used as normalizers, may dramatically change conclusions of quantitative PCR experiments. The effect of bowel inflammation on HKG remains unknown. Expression stability of 15 HKG (ACTB, B2M, GAPDH, GUSB, HPRT1, IPO8, MRPL19, PGK1, PPIA, RPLP0, RPS23, SDHA, TBP, UBC, and YWHAZ) in 166 bowel specimens (91 normal, 35 cancerous, and 40 inflamed) was ranked by coefficients of variation (CV%) or using dedicated software: geNorm and NormFinder. The RPS23, PPIA, and RPLP0 were top-ranked, whereas IPO8, UBC and TBP were the lowest-ranked HKG across inflamed/cancerous/normal colonic tissues. The pairs RPS23/RPLP0, PGK1/MRPL19, or PPIA/RPLP0 were optimal reference by CV%, NormFinder, and geNorm, respectively. Colon inflammation affected HKG more pronouncedly than cancer with ACTB significantly down- and B2M upregulated. In inflammatory bowel disease (IBD), different genes were top-ranked in a large and small bowel, whereas TBP, UBC, and IPO8 were lowest-ranked in both. For patients with IBD at large, RPS23/PPIA, PGK1/MRPL19, and PPIA/RPLP0 were found optimal by CV%, NormFinder, and geNorm, respectively. ACTB and B2M expression was related to CRC stage and positively correlated with clinical activity of IBD. Although GAPDH was upregulated neither in CRC nor IBD, it tended to positively correlate with tumor depth and Crohn's disease activity index. Normalizing against GAPDH affected experimental conclusions in a small but not large bowel. Bowel inflammation significantly affects several classic HKG. The pair PPIA/RPLP0 is a common optimal reference for studies encompassing tissues sampled from colorectal cancer and IBD patients. Using ACTB or B2M is not recommended.

Kim JY, Yi BR, Go RE, et al.
Methoxychlor and triclosan stimulates ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an estrogen receptor-dependent pathway.
Environ Toxicol Pharmacol. 2014; 37(3):1264-74 [PubMed] Related Publications
Methoxychlor and triclosan are emergent or suspected endocrine-disrupting chemicals (EDCs). Methoxychlor [MXC; 1,1,1-trichlor-2,2-bis (4-methoxyphenyl) ethane] is an organochlorine pesticide that has been primarily used since dichlorodiphenyltrichloroethane (DDT) was banned. In addition, triclosan (TCS) is used as a common component of soaps, deodorants, toothpastes, and other hygiene products at concentrations up to 0.3%. In the present study, the potential impact of MXC and TCS on ovarian cancer cell growth and underlying mechanism(s) was examined following their treatments in BG-1 ovarian cancer cells. As results, MXC and TCS induced BG-1 cell growth via regulating cyclin D1, p21 and Bax genes related with cell cycle and apoptosis. A methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay confirmed that the proliferation of BG-1 ovarian cancer cells was stimulated by MXC (10(-6), 10(-7), 10(-8), and 10(-9)M) or TCS (10(-6), 10(-7), 10(-8), and 10(-9)M). Treatment of BG-1 cells with MXC or TCS resulted in the upregulation of cyclin D1 and downregulation of p21 and Bax transcriptions. In addition, the protein level of cyclin D1 was increased by MXC or TCS while p21 and Bax protein levels appeared to be reduced in these cells. Furthermore, MXC- or TCS-induced alterations of these genes were reversed in the presence of ICI 182,780 (10(-7)M), suggesting that the changes in these gene expressions may be regulated by an ER-dependent signaling pathway. In conclusion, the results of our investigation indicate that two potential EDCs, MXC and TCS, may stimulate ovarian cancer growth by regulating cell cycle- and apoptosis-related genes via an ER-dependent pathway.

Almeida TA, Quispe-Ricalde A, Montes de Oca F, et al.
A high-throughput open-array qPCR gene panel to identify housekeeping genes suitable for myometrium and leiomyoma expression analysis.
Gynecol Oncol. 2014; 134(1):138-43 [PubMed] Related Publications
OBJECTIVE: To evaluate 51 different housekeeping genes for their use as internal standards in myometrial and matched leiomyoma samples in proliferative and secretory phases.
METHODS: RNA from 6 myometrium and matched leiomyoma samples was obtained from pre-menopausal women who underwent hysterectomy. Reverse-transcription and real-time quantitative PCR were achieved using TaqMan high-density open-array human endogenous control panel.
RESULTS: Expression stability of 51 candidate genes was determined by GeNorm and NormFinder softwares. We identified 10 housekeeping genes, ARF1, MRPL19, FBXW2, PUM1, UBE2D2, EIF2B1, HPRT1, GUSB, ALAS1, and TRIM27, as the best set of normalization genes for comparing relative expression between leiomyoma and myometrium samples in proliferative and secretory phases.
CONCLUSIONS: Adequate reference genes for accurate normalization are essential to compare gene expression between leiomyoma and myometrial samples. Ideal housekeeping genes must have stable expression patterns regardless of the sample type and menstrual cycle phase. In this study, we propose a set of 10 candidate genes with greater expression stability than those housekeeping genes commonly used in leiomyoma and myometrium tissues. Their use will improve the sensitivity and specificity of the gene expression analysis in these tissues.

Musrap N, Karagiannis GS, Saraon P, et al.
Proteomic analysis of cancer and mesothelial cells reveals an increase in Mucin 5AC during ovarian cancer and peritoneal interaction.
J Proteomics. 2014; 103:204-15 [PubMed] Related Publications
UNLABELLED: Ovarian cancer is a highly metastatic disease that is often characterized by widespread abdominal dissemination. A hallmark of ovarian cancer progression is the attachment of malignant cells to the mesothelium and the formation of invasive peritoneal implants. Therefore, delineating factors involved in cancer-peritoneal cell interaction is critical to improving patient survival, as it may lead to the discovery of novel therapeutic targets. As such, we aimed to identify proteins that participate in this interaction by comparing the secreted proteome of a co-culture model containing ovarian cancer (OVCAR-5) and mesothelial cells (LP-9), to their respective monoculture secretomes. In total, 49 proteins were differentially secreted during cancer and mesothelial cell contact. Relative mRNA expression of candidates was performed, which revealed a significant increase in MUC5AC gene expression in cancer cells cultured in three different co-culture models (OVCAR-5 and LP-9; BG-1 and LP-9; OV-90 and LP-9). An increased expression was also observed in LP-9 cells that were co-cultured with OVCAR-5 and OV-90 cancer cells. Further immunocytochemistry analysis also confirmed increased expression of MUC5AC in ovarian cancer and peritoneal co-cultures. Overall, our analysis uncovers novel molecular markers of peritoneal metastasis, which may have potential roles in regulating the progression of the disease.
BIOLOGICAL SIGNIFICANCE: In this study, our objective was to focus on identifying novel mediators of ovarian cancer and peritoneal interaction using a mass spectrometry-based approach. Our analysis resulted in the discovery of both previously known and novel factors involved this interaction, and as such, these newly discovered proteins might have potential roles in cancer progression, such as invasion and adhesion. We believe that these findings add to our current knowledge and understanding of ovarian cancer progression, and will aid researchers in their future attempts in finding new targets of the disease.

Waldron L, Haibe-Kains B, Culhane AC, et al.
Comparative meta-analysis of prognostic gene signatures for late-stage ovarian cancer.
J Natl Cancer Inst. 2014; 106(5) [PubMed] Related Publications
BACKGROUND: Ovarian cancer is the fifth most common cause of cancer deaths in women in the United States. Numerous gene signatures of patient prognosis have been proposed, but diverse data and methods make these difficult to compare or use in a clinically meaningful way. We sought to identify successful published prognostic gene signatures through systematic validation using public data.
METHODS: A systematic review identified 14 prognostic models for late-stage ovarian cancer. For each, we evaluated its 1) reimplementation as described by the original study, 2) performance for prognosis of overall survival in independent data, and 3) performance compared with random gene signatures. We compared and ranked models by validation in 10 published datasets comprising 1251 primarily high-grade, late-stage serous ovarian cancer patients. All tests of statistical significance were two-sided.
RESULTS: Twelve published models had 95% confidence intervals of the C-index that did not include the null value of 0.5; eight outperformed 97.5% of signatures including the same number of randomly selected genes and trained on the same data. The four top-ranked models achieved overall validation C-indices of 0.56 to 0.60 and shared anticorrelation with expression of immune response pathways. Most models demonstrated lower accuracy in new datasets than in validation sets presented in their publication.
CONCLUSIONS: This analysis provides definitive support for a handful of prognostic models but also confirms that these require improvement to be of clinical value. This work addresses outstanding controversies in the ovarian cancer literature and provides a reproducible framework for meta-analytic evaluation of gene signatures.

Guan HB, Wu L, Wu QJ, et al.
Parity and pancreatic cancer risk: a dose-response meta-analysis of epidemiologic studies.
PLoS One. 2014; 9(3):e92738 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: Previous epidemiologic studies have reported inconsistent results between parity and pancreatic cancer (PC) risk. To our knowledge, a comprehensive and quantitative assessment of this association has not been conducted.
METHODS: Relevant published studies of parity and PC were identified using MEDLINE (PubMed) and Web of Science databases until November 2013. Two authors (H-BG and LW) independently assessed eligibility and extracted data. Eleven prospective and 11 case-control studies reported relative risk (RR) estimates and 95% confidence intervals (CIs) of PC associated with parity. Fixed- and random-effects models were used to estimate the summary RR depending on the heterogeneity of effects.
RESULTS: The summary RR for PC comparing the highest versus lowest parity was 0.86 (95% CI: 0.73-1.02; Q = 50.49, P<0.001, I2 = 58.4%). Significant inverse associations were also observed in the studies that adjusted for cigarette smoking (RR = 0.81; 95% CI: 0.68-0.98), Type 2 diabetes mellitus (RR = 0.83; 95% CI: 0.75-0.93), and those that included all confounders or important risk factors (RR = 0.85; 95% CI: 0.76-0.96). Additionally, in the dose-response analysis, the summary RR for per one live birth was 0.97 (95% CI: 0.94-1.01; Q = 62.83, P<0.001, I2 = 69.8%), which also indicated a borderline statistically significant inverse effect of parity on PC risk. No evidence of publication bias and significant heterogeneity between subgroups were detected by meta-regression analyses.
CONCLUSION: In summary, these findings suggest that higher parity is associated with a decreased risk of PC. Future large consortia or pooled studies are warranted to fully adjust for potential confounders to confirm this association.

Li S, Li Y, Wen Z, et al.
microRNA-206 overexpression inhibits cellular proliferation and invasion of estrogen receptor α-positive ovarian cancer cells.
Mol Med Rep. 2014; 9(5):1703-8 [PubMed] Related Publications
The expression levels of estrogen receptor (ER α) are closely associated with estrogen-dependent growth, invasion and response to endocrine therapy in ERα-positive ovarian cancer. However, the underlying regulatory mechanisms remain to be fully understood. Previous studies have demonstrated that ERα is a direct target of microRNA (miR)-206. miR-206 has been found to be an important tumor suppressor in several cancer types, including ovarian, gastric and laryngeal cancer. However, the specific role of miR-206 in ovarian cancer remains unclear. The aim of the present study was to investigate the role of miR-206 in ER-a positive ovarian cancer in vitro. The present study demonstrated that miR-206 is significantly downregulated in ERα-positive but not ERα‑negative ovarian cancer tissues, compared with normal ovarian epithelium tissue. It was also found that the expression of miR-206 was decreased in ERα-positive ovarian cancer cell lines, CAOV-3 and BG-1, compared with normal ovarian epithelium tissues. This suggests that miR-206 may play a role in ERα-positive ovarian cancer cells via an estrogen-dependent mechanism. Further analysis revealed that 17β-E2 treatment significantly promoted cellular proliferation and invasion of estrogen-dependent CAOV-3 and BG-1 cells, which could be reversed by the introduction of miR-206 mimics. In conclusion, the present study suggests that miR-206 has an inhibitory role in estrogen-dependent ovarian cancer cells. Thus, miR-206 may be a promising candidate for the endocrine therapy of ERα-positive ovarian cancer.

Zhan C, Zhang Y, Ma J, et al.
Identification of reference genes for qRT-PCR in human lung squamous-cell carcinoma by RNA-Seq.
Acta Biochim Biophys Sin (Shanghai). 2014; 46(4):330-7 [PubMed] Related Publications
Although the accuracy of quantitative real-time polymerase chain reaction (qRT-PCR) is highly dependent on the reliable reference genes, many commonly used reference genes are not stably expressed and as such are not suitable for quantification and normalization of qRT-PCR data. The aim of this study was to identify novel reliable reference genes in lung squamous-cell carcinoma. We used RNA sequencing (RNA-Seq) to survey the whole genome expression in 5 lung normal samples and 44 lung squamous-cell carcinoma samples. We evaluated the expression profiles of 15 commonly used reference genes and identified five additional candidate reference genes. To validate the RNA-Seq dataset, we used qRT-PCR to verify the expression levels of these 20 genes in a separate set of 100 pairs of normal lung tissue and lung squamous-cell carcinoma samples, and then analyzed these results using geNorm and NormFinder. With respect to 14 of the 15 common reference genes (B2M, GAPDH, GUSB, HMBS, HPRT1, IPO8, PGK1, POLR2A, PPIA, RPLP0, TBP, TFRC, UBC, and YWHAZ), the expression levels were either too low to be easily detected, or exhibited a high degree of variability either between lung normal and squamous-cell carcinoma samples, or even among samples of the same tissue type. In contrast, 1 of the 15 common reference genes (ACTB) and the 5 additional candidate reference genes (EEF1A1, FAU, RPS9, RPS11, and RPS14) were stably and constitutively expressed at high levels in all the samples tested. ACTB, EEF1A1, FAU, RPS9, RPS11, and RPS14 are ideal reference genes for qRT-PCR analysis of lung squamous-cell carcinoma, while 14 commonly used qRT-PCR reference genes are less appropriate in this context.

Xie FW, Peng YH, Chen X, et al.
Regulation and expression of aberrant methylation on irinotecan metabolic genes CES2, UGT1A1 and GUSB in the in-vitro cultured colorectal cancer cells.
Biomed Pharmacother. 2014; 68(1):31-7 [PubMed] Related Publications
OBJECTIVE: To evaluate the aberrant methylation gene expression related to the irinotecan (CPT-11) metabolic enzymes in different colorectal cancer cell strains; provide new thoughts and measures for reverse of tumor drug resistance.
METHODS: Studied the aberrant methylation state of CES2, UGT1A1 and GUSB in eight colorectal cancer cell strains through MSP method; and analyze the expression of the target gene after being dealt with DAC.
RESULTS: UGT1A1 showed methylation in five cell strains, while CES2 and GUSB respectively showed consistent unmethylation or hemimethylation. After being dealt with DAC, CES2 and GUSB mRNA showed different expressions but not significant. The expression quantity of UGT1A1mRNA in the low-expression cell strains increased significantly. The expression of UGT1A1 protein where POSITIVE presented low expression was up-regulated to different degrees. Negative tropism was found in CES2 and UGT1A1.
CONCLUSION: Methylation in UGT1A1 gene expression silencing as an important mechanism; methylation could provide an effective target for methylation regulation intervening in the treatment of CPT-11. Meanwhile, studies found that the changes in expressions of CES2 and GUSB might be resulted from some unknown target that still existed during the regulation, or from the influence of methylation in the non-core zone of promoters on the gene transcription.

Park MA, Choi KC
Effects of 4-nonylphenol and bisphenol A on stimulation of cell growth via disruption of the transforming growth factor-β signaling pathway in ovarian cancer models.
Chem Res Toxicol. 2014; 27(1):119-28 [PubMed] Related Publications
Transforming growth factor β (TGF-β) signaling pathway is a major pathway in cellular processes such as cell growth, apoptosis, and cellular homeostasis. The signaling pathway activated by 17β-estadiol (E2) appeared to inhibit the TGF-β signaling pathway by cross-talk with the TGF-β components in estrogen receptor (ER) positive cells. In this study, we examined the inhibitory effects of endocrine disrupting chemicals (EDCs), including 4-nonylphenol (NP), 4-otylphenol (OP), bisphenol A (BPA), and benzophenon-1 (BP-1), in the TGF-β signaling pathway in BG-1 ovarian cancer cells expressing estrogen receptors (ERs). The transcriptional and translational levels of TGF-β related genes were examined by reverse transcription-PCR (RT-PCR), Western blot analysis, and xenograft mouse models of ovarian cancer cells. As a result, treatment with NP, OP, and BPA induced the expressions of SnoN, a TGF-β pathway inhibitor, and c-Fos, a TGF-β target transcription factor. Treatment with NP, BPA, and BP-1 resulted in decreased phosphorylation of Smad3, a downstream target of TGF-β. These results indicate that NP and BPA may stimulate the proliferation of BG-1 cells via inhibition of the TGF-β signaling pathway. In a xenograft mouse model, transplanted BG-1 ovarian cancer cells showed significantly decreased phosphorylation of Smad3 and increased expression of SnoN in the ovarian tumor masses following treatment with E2, NP, or BPA. In parallel with an in vitro model, the expressions of these TGF-β signaling pathway were similarly regulated by NP or BPA in a xenograft mouse model. These results support the fact that the existence of an unproven relationship between EDCs/ER-α and TGF-β signaling pathway and a further study are required in order to verify more profound and distinct mechanism(s) for the disturbance of the TGF-β signaling pathway by diverse EDCs.

Todorova R
Ewing's sarcoma cancer stem cell targeted therapy.
Curr Stem Cell Res Ther. 2014; 9(1):46-62 [PubMed] Related Publications
Ewing`s sarcoma (ES) family of tumors (ESFTs) are round cell tumors of bone and soft tissues, afflicting children and young adults. This review summarizes the present findings about ES cancer stem cell (CSC) targeted therapy: prognostic factors, chromosomal translocations, initiation, epigenetic mechanisms, candidate cell of ES origin (Mesenchymal stem cells (MSCs) and Neural crest stem cells (NCSCs)). The ES CSC model, histopathogenesis, histogenesis, pathogenesis, ES mediated Hematopoietic stem progenitor cells (HSPCs) senescence are also discussed. ESFTs therapy is reviewed concerning CSCs, radiotherapy, risk of subsequent neoplasms, stem cell (SC) support, promising therapeutic targets for ES CSCs (CSC markers, immune targeting, RNAi phenotyping screens, proposed new drugs), candidate EWS-FLI1 target genes and further directions (including human embryonic stem cells (hESCs)). Bone marrow-derived human MSCs are permissive for EWS-FLI1 expression with transition to ESFT-like cellular phenotype. ESFTs are genetically related to NCSC, permissive for EWS-FLI1 expression and susceptible to oncogene-induced immortalization. Primitive neuroectodermal features and MSC origin of ESFTs provide a basis of immune targeting. The microRNAs profile of ES CSCs is shared by ESCs and CSCs from divergent tumor types. Successful reprogramming of differentiated human somatic cells into a pluripotent state allows creation of patient- and disease-specific SCs. The functional role of endogenous EWS at stem cell level on both senescence and tumorigenesis is a link between cancer and aging. The regulatory mechanisms of oncogenic activity of EWS fusions could provide new prognostic biomarkers, therapeutic opportunities and tumor-specific anticancer agents against ESFTs.

Xie FW, Peng Y, Chen X, et al.
Relationship between the expression of CES2, UGT1A1, and GUSB in colorectal cancer tissues and aberrant methylation.
Neoplasma. 2014; 61(1):99-109 [PubMed] Related Publications
Irinotecan (CPT-11) is considered an important drug in the treatment of colorectal cancer, but its continuous administration reduces its sensitivity and influences the curative effect. The metabolism of CPT-11 is mainly controlled by carboxy-lesterase (CES), UDP-glucuronosyltransferase 1A (UGT1A), and β-glucuronidase (GUSB). Studies to date have shown that methylation acts as an important mechanism for gene expression to suppress the metabolic enzymes of many chemotherapeutics. This study, which selected 99 colorectal cancer patients, 23 of whom had paracancerous tissues and eight of whom had large intestine adenomas, aimed to investigate the correlation between the protein expression of the CPT-11 metabolic enzyme genes CES2, UGT1A1, and GUSB and various clinical pathological parameters of colorectal cancer tissues, as well as the relationship between methylation regulation and the gene expression of CES2, UGT1A1, and GUSB. We used immunohistochemistry staining, methylation-specific PCR, and clinical status to reveal the possible regulatory targets of chemotherapeutic resistance in colorectal cancer and to provide new ideas and countermeasures to reverse anti-cancer drug resistance and chemosensitization. The results showed that the expression of CES2, UGTA1A1, and GUSB varies in colorectal pathology tissues and that the expression of CES2 is somewhat related to tumor staging. This relationship is likely caused by the gene regulation of UGT1A1 and GUSB, and other regulation mechanisms may also be involved. The methylation of the CES2 gene is irrelevant to the morbidity associated with colorectal cancer. The GUSB gene showed no significant differences in methylation, and the hemi-methylation was also positive, the regulating ability of which needs to be verified. The potential role of these genes in the colorectal cancer progression, which may be directly related to the methylation regulation of UGT1A1, requires further research. The promoter of the UGT1A1 gene in colorectal cancer cells is methylated, which is an important mechanism of UGT1A1 gene silencing and can be regarded as the target point of research for CPT-11 drug resistance and control mechanisms for the reversal of drug resistance.

Fantasia F, Di Capua EN, Cenfra N, et al.
A highly specific q-RT-PCR assay to address the relevance of the JAK2WT and JAK2V617F expression levels and control genes in Ph-negative myeloproliferative neoplasms.
Ann Hematol. 2014; 93(4):609-16 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
In Ph- myeloproliferative neoplasms, the quantification of the JAK2V617F transcripts may provide some advantages over the DNA allele burden determination. We developed a q-RT-PCR to assess the JAK2WT and JAK2V617F mRNA expression in 105 cases (23 donors, 13 secondary polycythemia, 22 polycythemia vera (PV), 38 essential thrombocythemia (ET), and 9 primary myelofibrosis (PMF)). Compared with the standard allele-specific oligonucleotide (ASO)-PCR technique, our assay showed a 100 % concordance rate detecting the JAK2V617F mutation in 22/22 PV (100 %), 29/38 (76.3 %) ET, and 5/9 (55.5 %) PMF cases, respectively. The sensitivity of the assay was 0.01 %. Comparing DNA and RNA samples, we found that the JAK2V617F mutational ratios were significantly higher at the RNA level both in PV (p = 0.005) and ET (p = 0.001) samples. In PV patients, JAK2WT expression levels positively correlated with the platelets (PLTs) (p = 0.003) whereas a trend to negative correlation was observed with the Hb levels (p = 0.051). JAK2V617F-positive cases showed the lowest JAK2WT and ABL1 mRNA expression levels. In all the samples, the expression pattern of beta-glucoronidase (GUSB) was more homogeneous than that of ABL1 or β2 microglobulin (B2M). Using GUSB as normalizator gene, a significant increase of the JAK2V617F mRNA levels was seen in two ET patients at time of progression to PV. In conclusion, the proposed q-RT-PCR is a sensitive and accurate method to quantify the JAK2 mutational status that can also show clinical correlations suggesting the impact of the residual amount of the JAK2WT allele on the Ph- MPN disease phenotype. Our observations also preclude the use of ABL1 as a housekeeping gene for these neoplasms.

Goeppert B, Schmidt CR, Geiselhart L, et al.
Differential expression of the tumor suppressor A-kinase anchor protein 12 in human diffuse and pilocytic astrocytomas is regulated by promoter methylation.
J Neuropathol Exp Neurol. 2013; 72(10):933-41 [PubMed] Related Publications
The scaffold protein A-kinase anchor protein 12 (AKAP12) exerts tumor suppressor activity and is downregulated in several tumor entities. We characterized AKAP12 expression and regulation in astrocytomas, including pilocytic and diffusely infiltrating astrocytomas. We examined 194 human gliomas and 23 normal brain white matter samples by immunohistochemistry or immunoblotting for AKAP12 expression. We further performed quantitative methylation analysis of the AKAP12 promoter by MassARRAY® of normal brain, World Health Organization (WHO) grade I to IV astrocytomas, and glioma cell lines. Our results show that AKAP12 is expressed in a perivascular distribution in normal CNS, strongly upregulated in tumor cells in pilocytic astrocytomas, and weakly expressed in diffuse astrocytomas of WHO grade II to IV. Methylation analyses revealed specific hypermethylation of AKAP12α promoter in WHO grade II to IV astrocytomas. Restoration experiments using 5-aza-2'-deoxycytidine in primary glioblastoma cells decreased AKAP12α promoter methylation and markedly increased AKAP12α mRNA levels. In summary, we demonstrate that AKAP12 is differentially expressed in human astrocytomas showing high expression in pilocytic but low expression in diffuse astrocytomas of all WHO-grades. Our results further indicate that epigenetic mechanisms are involved in silencing AKAP12 in diffuse astrocytomas; however, a tumor suppressive role of AKAP12 in distinct astrocytoma subtypes remains to be determined.

Ehnert S, Freude T, Eicher C, et al.
Darbepoetin inhibits proliferation of hepatic cancer cells in the presence of TGF-β.
Arch Toxicol. 2014; 88(1):89-96 [PubMed] Related Publications
Darbepoetin (DPO), an erythropoietin (EPO) derivative, was licensed in 2002 to treat patients with solid tumors suffering from chemotherapy-dependent anemia, although various tumors express EPO to improve vascularization, thus favoring tumor growth and spreading. Therefore, we wanted to investigate direct effects of DPO on the liver tumor cell lines HepG2, SkHep1, Huh-7, AKN1, HCC-T and HCC-M, as well as on primary human hepatocytes (hHeps). DPO (0-40 ng/ml) did not affect viability of hHeps, HepG2, SkHep1, AKN1, HCC-T and HCC-M cells, as determined by Resazurin conversion. However, Huh-7 cells' viability dose-dependently decreased from 5 ng/ml DPO on. Lack of LDH release into culture medium and negative DNA laddering excluded apoptosis or necrosis as the cause for the reduced Resazurin conversion. In Huh-7 cells, DPO increased the expression of p53. Interestingly, Huh-7 cells showed the highest basal TGF-β1 expression as compared to the other cell lines. Upon inhibition of TGF-β1 signaling, DPO no longer reduced viability in Huh-7 cells. On the contrary, co-incubation with TGF-β1 made the other cell lines responsive to DPO. Summarizing our data, we show that DPO reduces the growth of Huh-7 cells by up-regulation of the tumor-suppressor gene p53. This mechanism seems to be dependent on a strong TGF-β expression and corresponding signaling in these cells, as other cell lines became responsive to DPO with TGF-β1 supplementation. The knowledge of this mechanism offers great perspectives for the understanding and treatment of solid liver tumors.

Barni S, Ghilardi M, Borgonovo K, et al.
Cetuximab/irinotecan-chemotherapy in KRAS wild-type pretreated metastatic colorectal cancer: a pooled analysis and review of literature.
Rev Recent Clin Trials. 2013; 8(2):101-9 [PubMed] Related Publications
INTRODUCTION: Cetuximab and irinotecan are effective agents in advanced colorectal cancer (CRC) after either irinotecanor oxaliplatin-based first-line chemotherapy. Here, the efficacy of this combination in patients with the KRAS wild-type gene as second- or further-line therapy is reviewed and data are collected in a pooled analysis.
METHODS: Studies that enrolled pretreated CRC patients for second-line therapy or beyond were identified using electronic databases (PubMed and EMBASE). A systematic analysis was conducted using Comprehensive Meta Analysis (version 2.2.064) to calculate the event rate of response and the 95% confidence interval. The weighted median overall survival (OS) and progression-free survival (PFS) were also calculated with NCSS 2007 software. We tested for significant heterogeneity using Cochran's chi-square test and the I(2) index.
RESULTS: Twenty-five studies published between 2007 and 2012 were eligible for this analysis, with a total of 1,712 KRAS wild-type patients enrolled. The overall response rate was 31.9% with similar response rates of 28. 7% for second-line treatment and 31.1% for third or further lines. The overall weighted median OS and PFS were 12.5 and 6 months with a weighted OS of 11.56 and 12.2 months for second- and further-line CRC settings, respectively.
CONCLUSION: In metastatic KRAS wild-type CRC patients pretreated with one or more lines of therapy, cetuximab plus irinotecan-based chemotherapy is an active treatment. Response rates and survival outcomes appear similar in second-line therapy or beyond.

Kang NH, Hwang KA, Lee HR, et al.
Resveratrol regulates the cell viability promoted by 17β-estradiol or bisphenol A via down-regulation of the cross-talk between estrogen receptor α and insulin growth factor-1 receptor in BG-1 ovarian cancer cells.
Food Chem Toxicol. 2013; 59:373-9 [PubMed] Related Publications
Endocrine disrupting chemicals (EDCs) and estrogens appear to promote development of estrogen-dependent cancers, including breast and ovarian carcinomas. In this study, we evaluated the cell viability effect of BPA on BG-1 human ovarian cancer cells, along with the growth inhibitory effect of resveratrol (trans-3,4,5-trihydroxystilbene; RES), a naturally occurring phytoestrogen. In addition, we investigated the underlying mechanism(s) of BPA and RES in regulating the interaction between estrogen receptor alpha (ERα) and insulin-like growth factor-1 receptor (IGF-1R) signals, a non- genomic pathway induced by 17β-estradiol (E2). BPA induced a significant increase in BG-1 cell growth and up-regulated mRNA levels of ERα and IGF-1R. In parallel with its mRNA level, the protein expression of ERα was induced, and phosphorylated insulin receptor substrate-1 (p-IRS-1), phosphorylated Akt1/2/3, and cyclin D1 were increased by BPA or E2. However, RES effectively reversed the BG-1 cell proliferation induced by E2 or BPA by inversely down-regulating the expressions of ERα, IGF-1R, p-IRS-1, and p-Akt1/2/3, and cyclin D1 at both transcriptional and translational levels. Taken together, these results suggest that RES is a novel candidate for prevention of tumor progression caused by EDCs, including BPA via effective inhibition of the cross-talk of ERα and IGF-1R signaling pathways.

Stanoszek LM, Crawford EL, Blomquist TM, et al.
Quality control methods for optimal BCR-ABL1 clinical testing in human whole blood samples.
J Mol Diagn. 2013; 15(3):391-400 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Reliable breakpoint cluster region (BCR)--Abelson (ABL) 1 measurement is essential for optimal management of chronic myelogenous leukemia. There is a need to optimize quality control, sensitivity, and reliability of methods used to measure a major molecular response and/or treatment failure. The effects of room temperature storage time, different primers, and RNA input in the reverse transcription (RT) reaction on BCR-ABL1 and β-glucuronidase (GUSB) cDNA yield were assessed in whole blood samples mixed with K562 cells. BCR-ABL1 was measured relative to GUSB to control for sample loading, and each gene was measured relative to known numbers of respective internal standard molecules to control for variation in quality and quantity of reagents, thermal cycler conditions, and presence of PCR inhibitors. Clinical sample and reference material measurements with this test were concordant with results reported by other laboratories. BCR-ABL1 per 10(3) GUSB values were significantly reduced (P = 0.004) after 48-hour storage. Gene-specific primers yielded more BCR-ABL1 cDNA than random hexamers at each RNA input. In addition, increasing RNA inhibited the RT reaction with random hexamers but not with gene-specific primers. Consequently, the yield of BCR-ABL1 was higher with gene-specific RT primers at all RNA inputs tested, increasing to as much as 158-fold. We conclude that optimal measurement of BCR-ABL1 per 10(3) GUSB in whole blood is obtained when gene-specific primers are used in RT and samples are analyzed within 24 hours after blood collection.

Becerikli M, Jacobsen F, Rittig A, et al.
Growth rate of late passage sarcoma cells is independent of epigenetic events but dependent on the amount of chromosomal aberrations.
Exp Cell Res. 2013; 319(12):1724-31 [PubMed] Related Publications
Soft tissue sarcomas (STS) are characterized by co-participation of several epigenetic and genetic events during tumorigenesis. Having bypassed cellular senescence barriers during oncogenic transformation, the factors further affecting growth rate of STS cells remain poorly understood. Therefore, we investigated the role of gene silencing (DNA promoter methylation of LINE-1, PTEN), genetic aberrations (karyotype, KRAS and BRAF mutations) as well as their contribution to the proliferation rate and migratory potential that underlies "initial" and "final" passage sarcoma cells. Three different cell lines were used, SW982 (synovial sarcoma), U2197 (malignant fibrous histiocytoma (MFH)) and HT1080 (fibrosarcoma). Increased proliferative potential of final passage STS cells was not associated with significant differences in methylation (LINE-1, PTEN) and mutation status (KRAS, BRAF), but it was dependent on the amount of chromosomal aberrations. Collectively, our data demonstrate that these fairly differentiated/advanced cancer cell lines have still the potential to gain an additional spontaneous growth benefit without external influences and that maintenance of increased proliferative potential towards longevity of STS cells (having crossed senescence barriers) may be independent of overt epigenetic alterations.

Hwang KA, Kang NH, Yi BR, et al.
Genistein, a soy phytoestrogen, prevents the growth of BG-1 ovarian cancer cells induced by 17β-estradiol or bisphenol A via the inhibition of cell cycle progression.
Int J Oncol. 2013; 42(2):733-40 [PubMed] Related Publications
An endocrine disrupting chemical (EDC) is a global health concern. In this study, we examined the effects of genistein (GEN) on bisphenol A (BPA) or 17β-estradiol (E2)-induced cell growth and gene alterations of BG-1 ovarian cancer cells expressing estrogen receptors (ERs). In an in vitro cell viability assay, E2 or BPA significantly increased the growth of BG-1 cells. This increased proliferative activity was reversed by treatment with ICI 182,780, a well-known ER antagonist, while cell proliferation was further promoted in the presence of propyl pyrazole triol (PPT), an ERα agonist. These results imply that cell proliferation increased by E2 or BPA was mediated by ERs, particularly ERα. BPA clearly acted as a xenoestrogen in BG-1 ovarian cancer cells by mimicking E2 action. In contrast, GEN effectively suppressed BG-1 cell proliferation promoted by E2 or BPA by inhibiting cell cycle progression. E2 and BPA increased the expression of cyclin D1, a factor responsible for the G1/S cell cycle transition. They also decreased the expression of p21, a potent cyclin-dependent kinase (CDK) inhibitor that arrests the cell cycle in G1 phase, and promoted the proliferation of BG-1 cells. As shown by its repressive effect on cell growth, GEN decreased the expression of cyclin D1 augmented by E2 or BPA. On the other hand, GEN increased the p21 expression downregulated by E2 or BPA. Collectively, our findings suggest that GEN, a dietary phytoestrogen, has an inhibitory effect on the growth of estrogen-dependent cancers promoted by E2 or BPA.

Quail DF, Zhang G, Walsh LA, et al.
Embryonic morphogen nodal promotes breast cancer growth and progression.
PLoS One. 2012; 7(11):e48237 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Breast cancers expressing human embryonic stem cell (hESC)-associated genes are more likely to progress than well-differentiated cancers and are thus associated with poor patient prognosis. Elevated proliferation and evasion of growth control are similarly associated with disease progression, and are classical hallmarks of cancer. In the current study we demonstrate that the hESC-associated factor Nodal promotes breast cancer growth. Specifically, we show that Nodal is elevated in aggressive MDA-MB-231, MDA-MB-468 and Hs578t human breast cancer cell lines, compared to poorly aggressive MCF-7 and T47D breast cancer cell lines. Nodal knockdown in aggressive breast cancer cells via shRNA reduces tumour incidence and significantly blunts tumour growth at primary sites. In vitro, using Trypan Blue exclusion assays, Western blot analysis of phosphorylated histone H3 and cleaved caspase-9, and real time RT-PCR analysis of BAX and BCL2 gene expression, we demonstrate that Nodal promotes expansion of breast cancer cells, likely via a combinatorial mechanism involving increased proliferation and decreased apopotosis. In an experimental model of metastasis using beta-glucuronidase (GUSB)-deficient NOD/SCID/mucopolysaccharidosis type VII (MPSVII) mice, we show that although Nodal is not required for the formation of small (<100 cells) micrometastases at secondary sites, it supports an elevated proliferation:apoptosis ratio (Ki67:TUNEL) in micrometastatic lesions. Indeed, at longer time points (8 weeks), we determined that Nodal is necessary for the subsequent development of macrometastatic lesions. Our findings demonstrate that Nodal supports tumour growth at primary and secondary sites by increasing the ratio of proliferation:apoptosis in breast cancer cells. As Nodal expression is relatively limited to embryonic systems and cancer, this study establishes Nodal as a potential tumour-specific target for the treatment of breast cancer.

Bossard C, Busson M, Vindrieux D, et al.
Potential role of estrogen receptor beta as a tumor suppressor of epithelial ovarian cancer.
PLoS One. 2012; 7(9):e44787 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Ovarian cancer is the gynecological cancer exhibiting the highest morbidity and improvement of treatments is still required. Previous studies have shown that Estrogen-receptor beta (ERβ) levels decreased along with ovarian carcinogenesis. Here, we present evidence that reintroduction of ERβ in BG-1 epithelial ovarian cancer cells, which express ERα, leads in vitro to a decrease of basal and estradiol-promoted cell proliferation. ERβ reduced the frequency of cells in S phase and increased the one of cells in G2/M phase. At the molecular level, we found that ERβ downregulated total retinoblastoma (Rb), phosphorylated Rb and phospho-AKT cellular content as well as cyclins D1 and A2. In addition, ERβ had a direct effect on ERα, by strongly inhibiting its expression and activity, which could explain part of the anti-proliferative action of ERβ. By developing a novel preclinical model of ovarian cancer based on a luminescent orthotopic xenograft in athymic Nude mice, we further revealed that ERβ expression reduces tumor growth and the presence of tumor cells in sites of metastasis, hence resulting in improved survival of mice. Altogether, these findings unveil a potential tumor-suppressor role of ERβ in ovarian carcinogenesis, which could be of potential clinical relevance for the selection of the most appropriate treatment for patients.

Tanic N, Milovanovic Z, Tanic N, et al.
The impact of PTEN tumor suppressor gene on acquiring resistance to tamoxifen treatment in breast cancer patients.
Cancer Biol Ther. 2012; 13(12):1165-74 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Tamoxifen is a standard therapeutical treatment in patients with estrogen receptor positive breast carcinoma. However, less than 50% of estrogen receptor positive breast cancers do not respond to tamoxifen treatment whereas 40% of tumors that initially respond to treatment develop resistance over time. The underlying mechanisms for tamoxifen resistance are probably multifactorial but remain largely unknown. The primary aim of this study was to investigate the impact of PTEN tumor suppressor gene on acquiring resistance to tamoxifen by analyzing loss of heterozygosity (LOH) and immunohystochemical expression of PTEN in 49 primary breast carcinomas of patients treated with tamoxifen as the only adjuvant therapy. The effect of PTEN inactivation on breast cancer progression and disease outcome was also analyzed. Reduced or completely lost PTEN expression was observed in 55.1% of samples, while 63.3% of samples displayed LOH of PTEN gene. Inactivation of PTEN immunoexpression significantly correlated with the PTEN loss of heterozygosity, suggesting LOH as the most important genetic mechanism for the reduction or complete loss of PTEN expression in primary breast carcinoma. Most importantly, LOH of PTEN and consequential reduction of its immunoexpression showed significant correlation with the recurrence of the disease. Besides, our study revealed that LOH of PTEN tumor suppressor was significantly associated with shorter disease free survival, breast cancer specific survival and overall survival. In summary, our results imply that LOH of PTEN could be used as a good prognostic characteristic for the outcome of breast cancer patients treated with tamoxifen.

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