Polymorphisms in the promoter region of ESR2 gene and susceptibility to ovarian cancer.

Susceptibility to ovarian cancer might be affected by genetic variations in genes involved in estrogen biosynthesis, metabolism or signal transduction. In this study we tested the hypothesis that single nucleotide polymorphisms (SNPs) in the promoter of human ESR2 gene, coding for estrogen receptor ß, may be associated with increased risk for ovarian cancer. Three SNPs in the promoter region of human ESR2 gene were genotyped by means of allele-specific tetra-primer PCR. A total of 184 ovarian cancer cases and the same numbers of controls were included in the study. With regard to homozygous analysis, the AA genotype of SNP rs3020449 was found to be significantly more frequent in ovarian cancer cases staged as FIGO III+IV than in cases staged as I+II (OR 2.717, p=0.027). With regard to allele frequency, the G allele of this SNP was less frequent in FIGO I+II cases than in cases with higher FIGO stages (OR 1.739, p=0.018). With regard to genotype frequency, allele frequency, allele positivity or haplotype frequency of SNPs rs2987983, rs3020449 and rs3020450 we did not observe a significant difference between the cancer and the control group. Our data suggest that SNPs in the promoter region of ESR2 gene do not affect susceptibility to ovarian cancer, but SNP rs3020449 might affect progression of this disease.

Icb-1 gene polymorphism rs1467465 is associated with susceptibility to ovarian cancer.

In this study, we tested the hypothesis that single nucleotide polymorphisms (SNPs) of differentiation-associated human gene icb-1 (C1orf38) may be associated with ovarian cancer susceptibility. For this purpose, we compared the genotype and allele frequencies of the SNPs rs1467465 and rs12048235 in a group of 184 ovarian cancer patients with a control group of 184 age- and gender-matched women without any malignancy. Genotype-phenotype association revealed that A allele of SNP rs1467465 was more frequent in ovarian cancer patients than in the control group (0.40 vs. 0.33, OR 1.37, 95% CI 1.013-1.853, p = 0.04). After analysis of allele positivity we observed that A-positive genotypes were more frequent in the ovarian cancer group (0.65 vs. 0.53, OR 1.63, 95% CI 1.072-2.483, p = 0.02). Furthermore, the heterozygous genotype of rs1467465 was found to be more frequent in the patients group (0.50 vs. 0.41, OR 1.63, 95% CI 1.045-2.045, p = 0.03). No significant results were obtained with regard to SNP rs1204823. Our data suggest, that SNP rs1467465 of human gene icb-1 might affect susceptibility to ovarian cancer.

Effects of estriol on growth, gene expression and estrogen response element activation in human breast cancer cell lines.

OBJECTIVE: Local application of estradiol (E2) to treat vulvovaginal atrophy in postmenopausal breast cancer patients receiving aromatase inhibitors is known to elevate serum estradiol levels and thereby might counteract breast cancer therapy. Thus, vaginal application of estriol (E3) has been recommended for these patients. However, it is unclear to what extent E3 stimulates breast cancer cell growth. In this study, we examined the effect of E3 on growth and gene expression of two human breast cancer cell lines. METHODS: We used an established in vitro cell culture assay and compared the effect of E2 and E3 on growth of the estrogen receptor alpha-positive breast cancer cell lines MCF-7 and T-47D testing a wide range of hormone concentrations of 10(-12)-10(-7)M. E3 effects on gene expression were examined by means of reporter gene assays, RT-qPCR and Western blot analysis. RESULTS: E3 acted as a potent estrogen and exerted a mitogenic effect on T-47D and MCF-7 cells at concentrations of 10(-9)M (288 pg/ml) and higher. With regard to activation of an estrogen response element (ERE) in breast cancer cells, effects of E3 were visible at 10(-10)M. The same concentrations of E3 activated expression of the estrogen-responsive gene PR and of the proliferation genes cyclin A2, cyclin B1, Ki-67, c-myc and b-myb, providing molecular mechanisms underlying the observed growth increase. CONCLUSIONS: Like E2, low levels of E3 were able to trigger a robust estrogenic response in breast cancer cells. Thus, our data suggest caution regarding use of E3 by breast cancer survivors.

Polymorphisms in the promoter region of estrogen receptor ß gene in endometrial cancer.

INTRODUCTION: The development of endometrial cancer is known to be affected by estrogens. Thus, genetic variations like single nucleotide polymorphisms (SNPs) in genes involved in estrogen biosynthesis, metabolism, and signal transduction might affect risk for endometrial cancer. In this study, we tested the hypothesis that polymorphisms in the promoter of ESR2 gene may be associated with susceptibility to this disease. METHODS: We compared the frequency of three SNPs in the promoter region of ESR2 gene (rs2987983, rs3020450, and rs3020449) in 135 women with endometrial cancer and 135 healthy women serving as controls by means of allele-specific tetra-primer PCR. RESULTS: Regarding allele frequency, allele positivity or genotype frequencies of these SNPs we did not observe any significant difference between healthy women and women with endometrial cancer. CONCLUSION: Our data clearly suggest that the tested SNPs in the promotor region of human ESR2 gene are not associated with the development of endometrial cancer.

Effects of a combined treatment with tamoxifen and estrogen receptor ß agonists on human breast cancer cell lines.

INTRODUCTION: Coexpression of estrogen receptors (ER) α and ß is present in about half of all breast cancer cases. Whereas ERα is a well-established target for endocrine therapy with the selective estrogen receptor modulator tamoxifen, the applicability of ERß as target in breast cancer therapy is unclear. In this study, we examined the effects of two synthetic ERß agonists alone and in combination with tamoxifen on ERα/ß-positive breast cancer cells. METHODS: We treated MCF-7 and T-47D breast cancer cells with the ERß agonists ERB-041 and WAY-200070 and measured the effects on cell growth. In addition, transcriptome analyses were performed by means of Affymetrix GeneChip arrays. RESULTS: When given alone, ERß agonists ERB-041 and WAY-200070 did not affect the growth of MCF-7 or T-47D cells. In contrast, addition of these drugs to tamoxifen increased its growth-inhibitory effect on both cell lines. This effect was more pronounced under serum-free conditions, but was also observed in the presence of serum in T-47D cells. Transcriptome analyses revealed a set of genes regulated after addition of ERß agonists including S100A8 and CD177. CONCLUSION: The observed enhanced growth-inhibitory effects of a combination of tamoxifen and ERß agonists in vitro encourage further studies to test its possible use in the clinical setting.

Expression of SCUBE2 gene declines in high grade endometrial cancer and associates with expression of steroid hormone receptors and tumor suppressor PTEN.

SCUBE2 (Signal peptide-CUB-epidermal growth factor-like domain-containing 2) gene codes for a cell-surface glycoprotein. In breast cancer, SCUBE2 transcript levels are part of important prognostic and predictive gene signatures and are linked to expression of estrogen receptor α (ERα). To elucidate the role of this gene in endometrial cancer, we compared SCUBE2 expression in malignant and normal endometrial tissue specimens. We then examined its correlation with steroid hormone receptors and PTEN and compared it to SCUBE2 expression in breast cancer samples. Expression of SCUBE2 was found to be decreased in G3 endometrial cancer when compared to postmenopausal endometrium or to G1 tumors (p < 0.05). In postmenopausal endometrium, SCUBE2 transcript levels were more than twice as high as in premenopausal women. In breast cancer, SCUBE2 expression was found to be notably reduced particularly in ERα-negative G3 tumors. Both in endometrial and breast cancer we observed a significant positive correlation of SCUBE2 transcript levels with expression of ERα, PR and PTEN. Our data suggest that SCUBE2, like in breast cancer, associates with ERα and might have a potential as prognostic or predictive marker in endometrial cancer.

G protein-coupled estrogen receptor (GPER) expression in endometrial adenocarcinoma and effect of agonist G-1 on growth of endometrial adenocarcinoma cell lines.

The G protein-coupled estrogen receptor (GPER, GPR30) is suggested to be involved in non-nuclear estrogen signaling and is expressed in a variety of hormone dependent cancer entities. This study was performed to further elucidate the role of this receptor in endometrial adenocarcinoma. We first analyzed GPER expression at the mRNA level in 88 endometrial cancer or normal endometrial tissue samples and compared it to those of nuclear steroid hormone receptors. GPER transcript levels were found to be about 6-fold reduced, but still present in endometrial cancer. Expression of this receptor was decreased in all grading subgroups when compared to pre- or postmenopausal endometrium. GPER mRNA expression was associated with PR mRNA levels (Spearman's rho 0.4610, p<0.001). We then tested the effect of the GPER ligand G-1 on growth of three endometrial cancer cell lines with different GPER expression. GPER protein levels were highest in RL95-2 cells, moderate in HEC-1A cells and not detectable in HEC-1B cells. The moderate expression level in HEC-1A cells was similar to average tumor tissue expression. Treatment with G-1 significantly inhibited growth of the GPER-positive cell lines RL95-2 and HEC-1A in a dose-dependent manner, whereas the GPER-negative line HEC-1B was not affected. Though GPER transcript levels were found to be reduced in endometrial cancer, our in vitro data suggest that moderate GPER expression might be sufficient to mediate growth-inhibitory effects triggered by its agonist G-1.

icb-1 Gene counteracts growth of ovarian cancer cell lines.

Human gene icb-1 has been originally identified to be involved in differentiation processes of cancer cells. To examine the function of icb-1 in ovarian cancer, we knocked down its expression in three ovarian cancer cell lines and performed microarray-based gene expression profiling with subsequent gene network modeling. Loss of icb-1 expression accelerated proliferation of SK-OV-3, OVCAR-3 and OAW-42 cells and led to upregulation of ovarian cancer biomarkers like KLK10 and CLDN16. Most of the upregulated genes were part of oncogenic pathways regulated by ERα or TNF. Our data suggest that icb-1 gene inhibits growth and progression of ovarian cancer cells.

Ovarian epithelial tumors and reproductive factors: a systematic review.

PURPOSE: The aim of this systematic review is to summarize the current knowledge about the etiology and pathogenesis of borderline tumors ovarian cancer with special emphasis on the role of endocrine treatments and reproductive factors to establish a foundation for future studies. METHODS: We performed a systematic review on the relation between ovarian epithelial tumors (OET) and reproductive factors using the keywords: ovarian cancer, ovarian tumor, ovarian borderline tumor, age at menarche, age at menopause, parity, infertility, PCO syndrome, oral contraception, menopausal hormone therapy, fertility treatment. Totally, 3,290 abstracts were scanned for their relevance in this publication and 127 were finally included. RESULTS: The incidence of ovarian epithelial cancer and ovarian borderline tumors is influenced by certain reproductive factors. The strongest protective effects are conferred by parity and use of oral contraceptive pills. Recent molecular biologic and histopathologic studies prove that OET represent a diverse group of tumors, each histologic type with a different genetic background. This is at least partly reflected in epidemiologic and clinical studies showing different risk modulating effects of reproductive factors and endocrine therapies on OET. CONCLUSIONS: The etiology and pathogenesis of ovarian cancer are still not fully understood. None of the so far proposed hypothesis on the development of OET can fully account for the epidemiologic and clinical findings in the context of reproductive factors and OET development. Further research approaches are warranted and need to put more weight on the clinical and genetical diversity of OET to yield a more detailed insight into their pathogenesis.

Estrogen receptor ß agonists affect growth and gene expression of human breast cancer cell lines.

Expression of estrogen receptor ß (ERß) has been described to reduce growth of cancer cell lines derived from hormone-dependent tumors, like breast cancer. In this study we tested to what extent two ERß agonists, androgen derivative 3ß-Adiol and flavonoid Liquiritigenin, would affect growth and gene expression of different ERß-positive human breast cancer cell lines. Under standard cell culture conditions, we observed 3ß-Adiol to inhibit growth of MCF-7 cells in a dose-dependent manner, whereas growth of BT-474 and MCF-10A cells was suppressed by the maximum concentration (100 nM) only. When treated in serum-free medium, all cell lines except of MDA-MB-231 were responsive to 1 nM 3ß-Adiol, and ZR75-1 cells exhibited a dose-dependent antiproliferative response. Providing putative mechanisms underlying the observed growth-inhibitory effect, expression of Ki-67 or cyclins A2 and B1 was downregulated after 3ß-Adiol treatment in all responsive lines. In contrast, treatment with lower doses of Liquiritigenin did not affect growth. In MCF-7 cells, the highest dose of this flavonoid exerted proliferative effects accompanied by increased expression of cyclin B1, PR and PS2, indicating unspecific activation of ERα. In conclusion, the ERß agonists tested exerted distinct concentration-dependent and cell line-specific effects on growth and gene expression. The observed inhibitory effects of 3ß-Adiol on breast cancer cell growth encourage further studies on the potential of this and other ERß agonists as targeted drugs for breast cancer therapy.

Role of estrogen receptor ß in gynecological cancer.

Estrogen receptor ß is expressed in normal and neoplastic ovarian and endometrial tissues. Recent studies indicate that levels of this receptor decline in ovarian tumorigenesis, like in breast or prostate cancer. Furthermore, ERß expression has been associated with good prognosis in ovarian cancer. In contrast, previous studies on the role of this receptor in endometrial cancer suggested that ERß might play different roles in the carcinogenesis of the ovary and endometrium. Besides its possible role as a prognostic factor, ERß might be a potential target for the treatment of ovarian and endometrial cancer.

Single nucleotide polymorphisms in the regulatory region of gonadotropin-releasing hormone receptor gene and breast cancer susceptibility.

It is known that exposure to estrogens affects the pathophysiology of breast cancer. The key role of gonadotropin-releasing hormone (GnRH) in the regulation of female steroid hormone metabolism raises the question of whether polymorphisms in its receptor, GnRHR, might influence breast cancer risk. To test this hypothesis, we analyzed three single nucleotide polymorphisms (SNPs) in the 5'-regulatory region of the GnRHR gene in a total of 565 women, 254 women with breast cancer and 311 women without any malignancy by allele-specific PCR. No significant differences were observed between the breast cancer and control group in terms of genotype, allele frequency or allele positivity. In contrast, different frequencies of the SNPs rs13138607, rs12644822 and rs3756159 were observed after sub-grouping the breast cancer cases according to tumor grading. Our data suggest a potential role of GnRHR gene polymorphisms in the development of breast cancer.

Network analysis of icb-1 gene function in human breast cancer cells.

Icb-1 is a human gene previously described by our group to exert important functions in cancer cells of different origin. We now performed microarray-based gene expression profiling with subsequent network modeling to further elucidate the role of icb-1 in breast cancer cells. Analyzing the effect of icb-1 knockdown on the transcriptome of MCF-7 cells, we found 151 differentially expressed genes exhibiting more than twofold changes, 97 of which were up- and 54 downregulated. Most of the upregulated genes were cancer-related genes associated with poor prognosis, invasion and metastasis, building an oncogenic network of TNF target genes. On the other hand, network analysis identified the downregulated genes to be primarily involved in interferon signaling and cellular apoptosis. Confirming these network data, we observed that cells with reduced levels of icb-1 exhibited an impaired response to the apoptosis inducers tamoxifen, staurosporine, actinomycin, and camptothecin. The data of this study suggest that icb-1 might exert a tumor-suppressor function in breast cancer and that its loss might confer relative resistance of breast cancer cells to apoptotic drugs.

Effects of a combined treatment with GPR30 agonist G-1 and herceptin on growth and gene expression of human breast cancer cell lines.

Expression of G-protein-coupled receptor 30 (GPR30) is present in HER2-overexpressing breast cancer. In this study, we examined to what extent GPR30-agonist G-1 would affect the antitumoral action of trastuzumab (Herceptin). Combined treatment with both drugs exerted an additive growth-inhibitory effect on breast cancer cells which was accompanied by a significant decline of cyclin A2 expression both on the protein and the mRNA level. Combined treatment also resulted in expression changes of c-fos, cyclin D1, or p21/WAF-1. The results of our study encourage further attempts to test the relevance of these in vitro data in the clinical setting.

Expression of cysteine protease cathepsin L is increased in endometrial cancer and correlates with expression of growth regulatory genes.

Proteases contribute to tumor invasion and metastasis by degrading basement membranes and extracellular matrix (ECM). In this study, we compared gene expression levels of two proteases, cysteine protease Cathepsin L2 (CTSL2) and matrix metalloproteinase MMP11, in human endometrium and endometrial cancer. Our data demonstrate CTSL2 transcript levels to be strongly elevated in endometrial cancer, particularly in G3 tumors. Furthermore, we observed a highly significant positive correlation of CTSL2 with expression of growth regulatory genes Ki-67, cyclin B1, MYBL2, p21/WAF, and HER2 receptor tyrosine kinase. Our data suggest that CTSL2 might be involved in progression of endometrial cancer.

SKP2 confers resistance of pancreatic cancer cells towards TRAIL-induced apoptosis.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dismal prognosis and no effective conservative therapy exists. Although the F-box protein S-phase kinase associated protein 2 (SKP2) is highly expressed and regulates cell cycle progression in PDAC, alternative SKP2 functions in PDAC are unknown. Using RNA interference we now demonstrate that SKP2 confers resistance of a subset of PDAC cell lines towards the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), but not the topoisomerase II inhibitor etoposide. We observed accelerated cleavage of the BH3-only protein Bid and augmented downregulation of cFLIPL, XIAP and MCL1 upon treatment of SKP2-depleted MiaPaCa2 cells with TRAIL. Our data disclose a novel SKP2 function in PDAC cells and therefore define SKP2 as a molecular target.

HDAC2 attenuates TRAIL-induced apoptosis of pancreatic cancer cells.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with a dismal prognosis and no effective conservative therapeutic strategies. Although it is demonstrated that histone deacetylases (HDACs), especially the class I HDACs HDAC1, 2 and 3 are highly expressed in this disease, little is known about HDAC isoenzyme specific functions. RESULTS: Depletion of HDAC2, but not HDAC1, in the pancreatic cancer cell lines MiaPaCa2 and Panc1 resulted in a marked sensitization towards the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Correspondingly, the more class I selective HDAC inhibitor (HDACI) valproic acid (VPA) synergized with TRAIL to induce apoptosis of MiaPaCa2 and Panc1 cells. At the molecular level, an increased expression of the TRAIL receptor 1 (DR5), accelerated processing of caspase 8, pronounced cleavage of the BH3-only protein Bid, and increased effector caspase activation was observed in HDAC2-depleted and TRAIL-treated MiaPaCa2 cells. CONCLUSIONS: Our data characterize a novel HDAC2 function in PDAC cells and point to a strategy to overcome TRAIL resistance of PDAC cells, a prerequisite to succeed with a TRAIL targeted therapy in clinical settings.

Targeting histone deacetylases in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with a median survival below 6 months and a 5-year survival rate below 1%. Effective therapies for locally advanced or metastatic tumours are missing and curatively resected patients relapse in over 80% of the cases. Although histone deacetylases (HDACs) are involved in the control of proliferation, apoptosis, differentiation, migration and angiogenesis of cancer cells, knowledge about the expression patterns and functions of individual HDAC isoenzymes in pancreatic cancer is sparse. This review summarizes the roles of HDACs as novel therapeutic targets and the molecular mode of action of HDAC-inhibitors (HDACI) in PDACs. Success of HDACI in clinical settings will depend on an increased knowledge of HDAC functions as well as on a better understanding of the mode of action of HDACI. Pre-clinical experimental data that constitute the basis for rational therapeutic strategies to treat PDAC are described here. Translating these rational-based therapies into the clinic will finally increase our chance to establish an effective HDACI-containing combination therapy effective against PDAC.

Susceptibility of coxsackievirus B3 laboratory strains and clinical isolates to the capsid function inhibitor pleconaril: antiviral studies with virus chimeras demonstrate the crucial role of amino acid 1092 in treatment.

OBJECTIVES: At present, most promising compounds to treat enterovirus-induced diseases are broad-spectrum capsid function inhibitors which bind into a hydrophobic pocket in viral capsid protein 1 (VP1). Coxsackievirus B3 (CVB3) Nancy was the only prototypic enterovirus strain shown to be pleconaril-resistant. This study was designed to better understand the polymorphism of the hydrophobic pocket in CVB3 laboratory strains and clinical isolates and its implications for treatment with the capsid function inhibitor pleconaril. METHODS: Pleconaril susceptibility was determined in cytopathic effect-inhibitory, plaque reduction or virus yield assays. Sequence analysis of the genome region coding for VP1 and/or subsequent alignment of amino acids lining the hydrophobic pocket of five CVB3 laboratory strains and 20 clinical isolates were carried out. Virus chimeras and computational analysis were used to prove the role of amino acid 1092. RESULTS AND CONCLUSIONS: Despite high conservation of pocket amino acids, polymorphism was detected at positions 1092, 1094 and 1180. Neither Pro-1094-->Thr nor Val-1180-->Ile altered efficacy of pleconaril treatment. But the amino acid at position 1092 was strongly associated with susceptibility of CVB3 to the capsid inhibitor. Whereas leucine was involved in resistance, isoleucine and valine were detected in pleconaril-susceptible CVB3. Results from antiviral assays with hybrid viruses demonstrate the crucial role of amino acid 1092 in pleconaril susceptibility. A resistant cDNA-generated CVB3 became pleconaril-susceptible after accepting parts from the genome region encoding Ile-1092 into its capsid. Computational analysis suggests that conformational changes in the hydrophobic pocket occur when leucine is substituted for isoleucine or valine and that this change leads to susceptibility to pleconaril.