Inhibitory effect of zinc, copper and selenium on telomerase activity in tumor tissues and t47d breast cancer cell line

The present study was performed to investigate the effects of trace elements particularity Se, Zn and Cu on tumor genesis in breast cancer. The inhibitory effect of Se, Zn and Cu, on telomerase activity was analyzed in human breast tumor tissues and breast cancer [T47D] cells. Tissue specimens from 24 women with benign breast disease and 32 women with breast cancer specimens [ductal carcinoma, lobular carcinoma] were collected during surgery. In addition venous blood samples were obtained for assessing the trace elements. T47D cell line was cultured and treated with trace elements. Telomerase activity then was measured with TRAP assay in cell line and tissue extracts. There was a significant difference between tissue and serum levels of Cu, Se and the ratio of Cu/Zn in patients and controls [P<0.001]. After treating with 100 microm/L Zn So4, 10 um /L Cu So4 for 6 hours, telomerase activity of T47D cells was markedly increased. But after treating with 10, and 30 um /L selenium-L- methionin, telomerase activity was markedly inhibited. Telomerase activity of T47D cells for 24 hours were 0.93, 0.60 and for 48 hours were 0.76, 0.12 respectively [control 49.2%]. There were variations in serum level of Zn and Cu in breast cancer patients. Association between trace elements level and telomerase activity level can be exploited as prognostic and diagnostic marker for breast cancer

[Study of prostate specific antigen gene expression and telomerase in breast cancer patients]

Breast cancer is the most common disease in women. In the expansion and progression of breast tumors combination of tumor markers including prostate specific antigen and telomerase are engaged. The aim of this study was to evaluate relationship between telomerase activity and prostate specific antigen gene expression in breast cancer patients and controls. This study was a case-control and consisted of 25 women diagnosed with breast benign tumors as control and 35 malignant tumors as cases. Telomerase activity was measured in tumor cytosol of samples by TRAP assay. PSA protein was measured using ultra sensitive immunoflourometric assay and PSA mRNA expression was making cleared using RTPCR techniques in all tumor tissues. Using TRAP assay, presence of the telomerase activity was positive in all of the breast cancer patients. The difference of relative telomerase activity [RTA] values between stages and also all grades were more statistically significant [p<0.05]. The PSA mRNA were detected only in benign tumors and stage I and grade I malignant tumor cytosols. Difference of tumor cytosol PSA levels between the cases and control groups and also between all grades and stages of diseases were significant [p <0.05]. In all, there was an inverse significant correlation between the RTA and PSA protein levels in the case groups [r=-0.42, p<0.05]. Our results showed a reverse relationship between PSA mRNA expression and increasing telomerase gene expression during breast cancer progression and development. In all, measurement of telomerase activity could be favorable biomarker along with PSA in breast cancer diagnosis