We hypothesize that estrogen receptors (ERs) are differentially expressed in endometrial cancer. ... more We hypothesize that estrogen receptors (ERs) are differentially expressed in endometrial cancer. To test this hypothesis, we investigated the expression profile of ERalpha (ERalpha-A, ERalpha-B, ERalpha-C) and ERbeta genes and CpG methylation status in endometrial cancer cell lines and tissues using reverse transcription-PCR and methylation-specific PCR and direct DNA sequencing. The results demonstrated that ERalpha-A, ERalpha-B, and ERbeta were normally expressed whereas ERalpha-C gene was inactivated in all endometrial cancer cell lines. We further investigated the mechanisms of ERalpha-C gene inactivation through CpG methylation pathways. The treatment with demethylating agent (5'-aza-2'-deoxycytidine) restored ERalpha-C gene expression in all endometrial cancer cell lines. We further confirmed these findings with methylation-specific PCR and direct DNA sequencing and found that only ERalpha-C was methylated on all five different CpG sites in all cell lines. We further a...
The expressions of two isoforms of human progesterone receptor (PR) are under the control of the ... more The expressions of two isoforms of human progesterone receptor (PR) are under the control of the two different promoters. Recent studies revealed differences between these isoforms, PRA and PRB, in their expression and function in endometrial cells. Aberrant methylation of normally unmethylated CpG islands has been associated with inactivation of several genes in human cancers. In this study, we investigated the methylation status and the expression of the two different PR isoforms, PRA and PRB, in uterine endometrial carcinoma (UEC) using methylation-specific PCR (MSP), reverse transcription-PCR (RT-PCR), the 5' rapid amplification of cDNA ends method (5'RACE), and immunohistochemical staining. The results of RT-PCR and 5'RACE suggest that only PRB is inactivated, although PRA is activated in all UEC cell lines. Treatment with a demethylating agent, 5-aza-2'-deoxycytidine, restored PRB expression in all cell lines, suggesting that inactivation of this gene is throug...
Androgens mediate their effects through the androgen receptor (AR) and have antiproliferative eff... more Androgens mediate their effects through the androgen receptor (AR) and have antiproliferative effects on uterine endometrial cells. In this report, we investigated methylation status and the expression of the AR gene in normal endometrium and uterine endometrial cancer (UEC) tissues using methylation-specific polymerase chain reaction (MSP) and immunohistochemical staining. Seventy of 89 cancer samples were AR negative, although 39 of 46 normal samples were AR positive by immunohistochemistry. By MSP, 64 of 89 cancer samples showed only methylated AR alleles, although all normal tissues showed both unmethylated and methylated AR alleles. To determine whether similar changes occurred in methylation status in the UEC carcinogenesis, we studied AR methylation using pairs of cancerous and normal samples from 28 patients. Twenty-three of 28 cancer samples showed only methylated AR alleles, although all normal samples showed both unmethylated and methylated alleles. All of the 23 cancer samples that lost unmethylated alleles were negative for AR by immunohistochemical analysis. Reverse transcription-polymerase chain reaction was performed by using UEC cell lines with and without treatment by the demethylating reagent 5-aza-2'-deoxycytidine. No AR expression was found in any of the UEC cell lines, except for MFE-296 without 5-aza-2'-deoxycytidine. Treatment with 5-aza-2'-deoxycytidine restored AR expression in all of the UEC cell lines that showed no AR expression before treatment. This study is the first to report that the possible mechanism of AR inactivation in endometrial cancer is through hypermethylation of the AR gene CpG islands.
BACKGROUND. The down-regulation of the estrogen receptor- (ER) gene is associated with several ... more BACKGROUND. The down-regulation of the estrogen receptor- (ER) gene is associated with several malignancies, including prostate carcinoma. The purpose of the current study was to investigate the mechanisms of ER inactivation through the analysis of CpG methylation of the promoter region of ER gene.
We hypothesize that estrogen receptors (ERs) are differentially expressed in endometrial cancer. ... more We hypothesize that estrogen receptors (ERs) are differentially expressed in endometrial cancer. To test this hypothesis, we investigated the expression profile of ERalpha (ERalpha-A, ERalpha-B, ERalpha-C) and ERbeta genes and CpG methylation status in endometrial cancer cell lines and tissues using reverse transcription-PCR and methylation-specific PCR and direct DNA sequencing. The results demonstrated that ERalpha-A, ERalpha-B, and ERbeta were normally expressed whereas ERalpha-C gene was inactivated in all endometrial cancer cell lines. We further investigated the mechanisms of ERalpha-C gene inactivation through CpG methylation pathways. The treatment with demethylating agent (5'-aza-2'-deoxycytidine) restored ERalpha-C gene expression in all endometrial cancer cell lines. We further confirmed these findings with methylation-specific PCR and direct DNA sequencing and found that only ERalpha-C was methylated on all five different CpG sites in all cell lines. We further a...
The expressions of two isoforms of human progesterone receptor (PR) are under the control of the ... more The expressions of two isoforms of human progesterone receptor (PR) are under the control of the two different promoters. Recent studies revealed differences between these isoforms, PRA and PRB, in their expression and function in endometrial cells. Aberrant methylation of normally unmethylated CpG islands has been associated with inactivation of several genes in human cancers. In this study, we investigated the methylation status and the expression of the two different PR isoforms, PRA and PRB, in uterine endometrial carcinoma (UEC) using methylation-specific PCR (MSP), reverse transcription-PCR (RT-PCR), the 5' rapid amplification of cDNA ends method (5'RACE), and immunohistochemical staining. The results of RT-PCR and 5'RACE suggest that only PRB is inactivated, although PRA is activated in all UEC cell lines. Treatment with a demethylating agent, 5-aza-2'-deoxycytidine, restored PRB expression in all cell lines, suggesting that inactivation of this gene is throug...
Androgens mediate their effects through the androgen receptor (AR) and have antiproliferative eff... more Androgens mediate their effects through the androgen receptor (AR) and have antiproliferative effects on uterine endometrial cells. In this report, we investigated methylation status and the expression of the AR gene in normal endometrium and uterine endometrial cancer (UEC) tissues using methylation-specific polymerase chain reaction (MSP) and immunohistochemical staining. Seventy of 89 cancer samples were AR negative, although 39 of 46 normal samples were AR positive by immunohistochemistry. By MSP, 64 of 89 cancer samples showed only methylated AR alleles, although all normal tissues showed both unmethylated and methylated AR alleles. To determine whether similar changes occurred in methylation status in the UEC carcinogenesis, we studied AR methylation using pairs of cancerous and normal samples from 28 patients. Twenty-three of 28 cancer samples showed only methylated AR alleles, although all normal samples showed both unmethylated and methylated alleles. All of the 23 cancer samples that lost unmethylated alleles were negative for AR by immunohistochemical analysis. Reverse transcription-polymerase chain reaction was performed by using UEC cell lines with and without treatment by the demethylating reagent 5-aza-2'-deoxycytidine. No AR expression was found in any of the UEC cell lines, except for MFE-296 without 5-aza-2'-deoxycytidine. Treatment with 5-aza-2'-deoxycytidine restored AR expression in all of the UEC cell lines that showed no AR expression before treatment. This study is the first to report that the possible mechanism of AR inactivation in endometrial cancer is through hypermethylation of the AR gene CpG islands.
BACKGROUND. The down-regulation of the estrogen receptor- (ER) gene is associated with several ... more BACKGROUND. The down-regulation of the estrogen receptor- (ER) gene is associated with several malignancies, including prostate carcinoma. The purpose of the current study was to investigate the mechanisms of ER inactivation through the analysis of CpG methylation of the promoter region of ER gene.
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Papers by Abhipsa Dharia