肿瘤坏死因子相关诱导凋亡配体与放化疗联用对喉癌细胞的协同杀伤效应及机制

Objective To determine the sensitivity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced apoptosis in Hep-2 cells by means of systematically evaluating the cytotoxicity of TRAIL alone and TRAIL in combination with chemotherapeutic agents (cisplatin, paclitaxel) or radiation in Hep-2 cells in vitro, and whether the synergistic killing effects correlated with the expression level of TRAIL receptors and the activity of caspnse-8 or caspase-9. Methods The cytotoxicities of TRAIL, cisplatin and paclitaxel were investigated by cell counting kit-8 (CCK-8) assay. The expression levels of four TRAIL receptors in Hep-2 cells after treated by TRAIL, chemotherapeutic agents or radiation alone and by combined treatments were measured by flow eytometry and Western blotting respectively. The growth inhibition effects of caspase-8 or caspase-9 inhibitor on Hep-2 cells were determined by CCK-8 assay, and the activities of caspase-8, caspase-9 and caspase-3 were measured by Western blotting. Results The half maximal inhibitory concentration(IC50) of TRAIL to Hep-2 ceils on 24 h was 596. 92 μg/L Cisplatin, paclitaxel and radiation had synergistic inhibitory effects with TRAIL on the growth of Hep-2 cell line. After the activity of caspase-9 was inhibited by Z-LETD-FMK, the inhibition effects of TRAIL, cisplatin and paclitaxel on Hep-2 cells decreased significantly (all P < 0. 05). The expressions of caspase-8, caspase-9 and the death receptors (DR4 and DR5) increased significantly (all P < 0. 05) after combined administration. Conclusions Hep-2 cells are resistant to the apoptosis induced by TRAIL and TRAIL can induce the apoptosis of Hep-2 cells through the endogenous apeptotic pathway. The increase of death receptors expression by chemotherapeutic agents or radiation could enhance the sensitivity of Hep-2 cells to TRAIL and the synergistic killing effects.

Synergistic effects and mechanisms of combined tumor necrosis factor-related apoptosis-inducing ligand and chemotherapeutic drugs or radiotherapy in killing laryngeal squamous carcinoma cells in vitro