Objective: To investigate apoptosis in T cells induced by ovarian carcinoma cells and analyze the role of nitric oxide and intracellular free calcium in this process.
Methods: Apoptosis induced by ovarian carcinoma cell lines supernatants was investigated by electron microscopy and flow cytometry. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of inducible nitric oxide synthase (iNOS) mRNA. Calcium ions ([Ca(2+)]i) and cycle guanosine monophosphate (cGMP) were determined by Fura-2 fluorescein load technique and enzyme immunoassay (EIA), respectively.
Results: Cluster of differentiation (CD)8(+) T cells cocultured with ovarian carcinoma cell lines supernatants expressed typical change of apoptosis, such as condensation and fragmentation of chromosomes, apoptosis peak in flow cytometry and higher apoptotic ratios[(23.8 +/- 3.5)%, (23.1 +/- 2.9)%, (24.2 +/- 4.9)% vs (4.6 +/- 0.5)%, P < 0.01]. The expression of iNOS mRNA and cGMP level in the process of CD(8)(+) T cellular apoptosis were significantly enhanced as compared to that of control group [1.14 +/- 0.03, 1.05 +/- 0.04, 1.16 +/- 0.02 vs 0.60 +/- 0.03, P < 0.01; (0.65 +/- 0.09), (0.62 +/- 0.16), (0.57 +/- 0.12) pmol/Lvs (0.29 +/- 0.04) pmol/ml, P < 0.01], and [Ca(2+)]i was significantly higher [(380 +/- 38), (366 +/- 13), (356 +/- 20) nmol/L vs (184 +/- 11) nmol/L, P < 0.01].
Conclusion: Nitric oxide and intracellular free calcium may play a key role in apoptotic T cell induced by ovarian carcinoma.