Proteasome inhibitors sensitize ovarian cancer cells to cisplatin / 中华妇产科杂志

ABSTRACT

Objective To explore the sensitivity and the molecular mechanism of cisplatinresistance ovarian cancer cell line C13 to proteasome inhibitors and the combination with cisplatin. Methods After different treatments, methyl thiazolyl tetrazolium (MTT) assay was applied to examine the cell viability, annexin-V/propidium iodide(PI) apoptosis detection kit was used to determine the apoptosis rate of different groups, western blot assay was introduced to evaluate the expression levels of Fas-associated death domain-like interleukin-1 beta converting enzyme inhibitory protein (cFLIPs), and the activity of caspase-8 was examined. Results MTT assay shown that the cell viability ratios of combination group at serial time points from 12, 24, 36, 48, 60, 72 hours were ( 56.0 ± 8.4 ) %, (44.7 ± 7.3 ) %, ( 33.7 ±11.2) %, (27.6 ± 8.0) %, (27. 6 ± 7.6) % and (28.1 ± 2.4) %, which were much lower than those of cisplatin group (P <0.05). After treated for 24 hours, apoptosis rates of cisplatin group, bortezomib group and combination group were ( 16.7 ± 1.7) %, (23.4 ± 2.1 ) % and (26.9 ± 1.6) %, respectively. The rate of combination group was much higher than that of non-treated group and that of cisplatin group or bortezomib group ( P < 0.05 ). Western blot assay showed the changes of expression levels of cFLIPs, which were downregulated seriously after cisplatin, bortezomib or combination treatment [ (43.2 ± 2.3 )% vs( 75.7 ± 3.0)%vs (67.9 ± 2.1 ) %, P < 0.05 ]. The caspase-8 activity of combination group was (5.6 ± 1.6) folds than that of non-treated group, which was higher than those of other two groups [ ( 2.3 ± 1.0) and (4.2 ± 0.9 ) folds,P < 0.05 ]. Conclusions The tumor cell lethal effect of cisplatin could be increase significantly by the combination application of proteasome inhibitors, bortezomib. And the cFLIPs/caspase-8 signaling pathway may be play an important role in the molecular mechanism of the combination treatment.