Several studies suggest that tumor necrosis factor-alpha (TNF) is able to overcome drug resistance in tumors. Whether TNF is able to do so in tumor cell lines that are drug resistant due to a ...mutation in the tumor suppressor gene p53 is unclear. Therefore, we studied the in vitro cytotoxic effects of TNF combined with various cytotoxic agents in a model consisting of a human ovarian cancer cell line containing endogenous wild-type p53 (wtp53) and sublines that were made drug resistant against various cytotoxic agents by transfection of several forms of mutated p53 (mtp53). Using the microculture tetrazolium assay, the cytotoxic effects of TNF alone, the cytotoxic agents VM-26, melphalan, cisplatin, vinblastine, paclitaxel, and mitoxantrone, plus the combined effects of 10 ng/ml TNF added 30 min before various concentrations of the cytotoxic agents were established. Compared with the control cell line (A2780/cmv), two cell lines transfected with mtp53 (A2780/m248 and A2780/m273) showed increased resistance against several cytotoxic agents but also an enhanced sensitivity to TNF. Interaction of TNF with the cytotoxic drugs was additive in the drug-sensitive control cell line as well as in the drug-resistant sublines. However, because of the increased sensitivity of A2780/m248 to TNF at the dose used for the combinations, the combination of TNF with several cytotoxic drugs reduced the level of resistance in A2780/m248 compared with the control cell line A2780/cmv. In conclusion, this study shows that addition of TNF can ameliorate resistance to cytotoxic agents in a subline that is drug-resistant because of mutated p53. This reduction in resistance by TNF is not due to synergistic interaction, but to collateral sensitivity to TNF.
Interferon-alpha (IFN-alpha) treatment in both oncological and hepatological settings is associated with depression. If IFN-alpha treatment induces depression in high numbers, it could serve as a ...model for studying the pathophysiology of depression, in general. The authors therefore studied 43 oncology patients treated with standard or pegylated IFN-alpha with baseline psychiatric assessment and at regular time-points in the first 6 months of treatment. Apart from a severe depression because of brain metastases, authors observed only two clinically relevant depressive states. Contrary to findings in most of the literature, most depressive episodes in this study were self-limiting and short-lasting and were associated with either episodes of flu-like symptoms common at the start of the treatment or with concurrent psychosocial events. In the group as a whole, scores on both observer-based and self-report rating scales did not show clinically relevant changes. The results of this study indicate that IFN-alpha treatment is not suitable as a study model for depression in general.
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