Annexin a5 as a new potential biomarker for Cisplatin-induced toxicity in human kidney epithelial cells.

Cisplatin is a member of platinum-containing anti-cancer drugs that causes cross-linking of DNA and ultimately cancer cell apoptosis. The therapeutic function of cisplatin on various types of cancers has been widely reported but the side effects have been discovered together and nephrotoxicity has been regarded as major side effect of cisplatin. To select candidates for new sensitive nephrotoxicity biomarker, we performed proteomic analysis using 2-DE/MALDI-TOF-MS followed by cisplatin treatment in human kidney cell line, HK-2 cells, and compared the results to the gene profi le from microarray composed of genes changed in expression by cisplatin from formerly reported article. Annexin A5 has been selected to be the most potential candidate and it has been identifi ed using Western blot, RT-PCR and cell viability assay whether annexin A5 is available to be a sensitive nephrotoxic biomarker. Treatment with cisplatin on HK-2 cells caused the increase of annexin A5 expression in protein and mRNA levels. Overexpression of annexin A5 blocked HK-2 cell proliferation, indicating correlation between annexin A5 and renal cell toxicity. Taken together, these results suggest the possibility of annexin A5 as a new biomarker for cisplatin-mediated nephrotoxicity.

Induction of steroid sulfatase expression by tumor necrosis factor-α through phosphatidylinositol 3-kinase/Akt signaling pathway in PC-3 human prostate cancer cells.

Steroid sulfatase (STS) is responsible for the hydrolysis of aryl and alkyl steroid sulfates and has a pivotal role in regulating the formation of biologically active estrogens. STS may be considered a new promising drug target for treating estrogen-mediated carcinogenesis. However, the molecular mechanism of STS expression is not well-known. To investigate whether tumor necrosis factor (TNF)-α is able to regulate gene transcription of STS, we studied the effect of TNF-α on STS expression in PC-3 human prostate cancer cells. RT-PCR and Western blot analysis showed that TNF-α significantly induced the expression of STS mRNA and protein in a concentration- and time-dependent manner. Treatment with TNF-α resulted in a strong increase in the phosphorylation of Akt on Ser-473 and when cells were treated with phosphatidylinositol (PI) 3-kinase inhibitors such as LY294002 or wortmannin, or Akt inhibitor (Akt inhibitor IV), induction of STS mRNA expression by TNF-α was significantly prevented. Moreover, activation of Akt1 by expressing the constitutively active form of Akt1 increased STS expression whereas dominant-negative Akt suppressed TNF-α-mediated STS induction. We also found that TNF-α is able to increase STS mRNA expression in other human cancer cells such as LNCaP, MDA-MB-231, and MCF-7 as well as PC-3 cells. Taken together, our results strongly suggest that PI 3-kinase/Akt activation mediates induction of human STS gene expression by TNF-α in human cancer cells.