Taxol-resistant ovarian cell

Short term treatment with TPA sensitized human 2008 ovarian carcinoma cells to cis-platin. This sensitization disappeared completely by seven hours after treatment, indicating that not inhibition, but activation of PKC sensitizes 2008 cells to the antiproliferative activity of cis-platin (Isonishi et al., 1990). Pretreatment of HeLa cells with TPA or PdBu caused a 9-fold increase in cellular sensitivity to cis-platin and 2.5-fold to melphalan, but had now effect on the antiproliferative activity of bleomycin, adriamycin, vincristine, or mitomycin C. The sensitization of HeLa cells by TPA was associated with a 6-fold stimulation of PKC activation and a concentration- and time-dependent increase in cellular platinum content. (Basu et al. 1990). PKC activity was found to be decreased significantly in cis-platin-resistant human small cell lung H69/CP cancer cells compared to the drug-sensitive variant. A similar reduction in PKC activity was noted in ovarian carcinoma 2008 cells that were resistant to cis-platin. A modest decrease in PKC activity was also observed in etoposide-resistant H69 cells but not in taxol-resistant H69 cells or bleomycin-resistant human head and neck carcinoma A-253 cells (Basu et al., 1996), indicating that reduced PKC activity leads to decreased sensitivity in this system. 

Zaffaroni N, Silvestrini R, Orlandi L, Bearzatto A, Gornati D, Villa R. Induction of apoptosis by taxol and cisplatin and effect on cell cycle-related proteins in cisplatin-sensitive and -resistant human ovarian cells. BrJ Cancer 1998 77(9) 1378-1385. 

Zaffaroni N, et al. Expression of the anti-apoptotic gene survivin 110. correlates with taxol resistance in human ovarian cancer. Cell... 

Investigators found that human breast cancer cell lines with BRCAl mutations showed a twofold to fourfold increase in apoptosis after treatment with ionizing radiation, cisplatin, or doxorubicin, compared with cells free of mutations. They also found that BRCAl tumor cell lines were resistant to other agents, such as paclitaxel (Taxol) and docetaxel (Taxotere), treatments used commonly in ovarian cancer and advanced-stage breast cancers. 

Kellard LR, Abel G. Comparative in vitro cytotoxicity of Taxol and Tax-otere against cisplatin-sensitive and resistant human ovarian carcinoma cell lines. Cancer Chemother Pharmacol 1992 30 444-450. 

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