[The roles of holothurian glycosaminoglycan combined with cisplatin on proliferation and chemotherapeutic response in A549 human lung adenocarcinoma cell].

Objective: To investigate the effects and mechanism of Holothurian Glycosaminoglycan (hGAG) alone in combination with cisplatin (DDP) on apoptosis of pulmonary adenocarcinoma cell A549. Methods: A549 cells were separately treated with blank, hGAG, DDP and hGAG combined with DDP (hGAG + DDP). The cell morphology in 4 groups was observed using light microscope. CCK8 assay was used to determine the cell viability. Flow cytometry by Hoechst 33258 and AnnexinV-FITC/PI staining was applied to detect cell apoptosis. Western blot was then used to detect the protein expression of Bax, Bcl-2, survivin and caspase-3. Results: After treatment for 24 h, the inhibitory rates of A549 cells in control, hGAG, DDP and hGAG + DDP groups were 0, (19.74±5.39)%, (42.01±2.57)% and (53.89±4.58)%, respectively. Moreover, after treatment for 48 h and 72 h, the inhibitory rates in each group were 0, (23.17±4.78)% and (29.17±4.21 )%, (54.00±7.64)% and (59.35±7.31)%, as well as (77.58±4.26)% and (79.94±4.58)%, respectively. The cell viability was significantly lower in drug treatment groups compared with those in control group at the same time point ( P <0.05). Hochest 33258 staining showed that no obvious apoptotic cells were detected in the control group, while apoptotic cells were visible in hGAG, cisplatin and combination groups. Flow cytometry showed that cell apoptotic rates were (2.38±0.59)%, (12.59±4.22)%, (16.36±3.63)% and (44.60±5.45)% in the control, hGAG, DDP and hGAG + DDP groups, respectively. The cell apoptosis was significantly lower in drug treatment groups compared with those in control group at the same time point ( P <0.05). Furthermore, western blot results showed that the expression of Bax and caspase-3 protein was increased ( P <0.05), whereas Bcl-2 and survivin was decreased ( P <0.05) in the hGAG+ DDP group compared with cisplatin alone ( P <0.05). Conclusions: HGAG can inhibit the proliferation and promote the apoptosis of human lung adenocarcinoma A549 cells. Meanwhile, it can strengthen the chemosensitivity of A549 cells to DDP via up-regulation of Bax, caspase-3 and down-regulation of Bcl-2 and survivin.