Exogenous hydrogen sulfide promotes C6glioma cell growth through activation of the p38MAPK/ERK1/2-COX-2 pathways.

Abstract

Hydrogen sulfide (H2S) participates in multifarious physiological and pathophysiologic progresses of cancer both invitro and invivo. We have previously demonstrated that exogenous H2S promoted liver cancer cells proliferation/anti‑apoptosis/angiogenesis/migration effects via amplifying the activation of NF-κB pathway. However, the effects of H2S on cancer cell proliferation and apoptosis are controversial and remain unclear in C6glioma cells. The present study investigated the effects of exogenous H2S on cancer cells growth via activating p38MAPK/ERK1/2-COX-2 pathways in C6glioma cells. C6glioma cells were treated with 400µmol/l NaHS (a donor of H2S) for 24h. The expression levels of phosphorylated (p)-p38MAPK, total (t)-p38MAPK, p-ERK1/2, t-ERK1/2, cyclooxygenase-2 (COX-2) and caspase-3 were measured by western blotting assay. Cell viability was detected by Cell Counting Kit-8 (CCK-8). Apoptotic cells were observed by Hoechst33258 staining assay. Cell proliferation was directly detected under fully automatic inverted microscope. Exposure of C6glioma cells to NaHS resulted in cell proliferation, as evidenced by an increase in cell viability. In addition, NaHS treatment reduced apoptosis, as indicated by the decreased apoptotic percentage and the cleaved caspase-3 expression. Importantly, exposure of the cells to NaHS increased the expression levels of p-p38MAPK, p-ERK1/2 and COX-2. Notably, co-treatment of C6glioma cells with 400µmol/l NaHS and AOAA (an inhibitor of CBS) largely suppressed the above NaHS-induced effects. Combined treatment with NaHS and SB203580 (an inhibitor of p38MAPK) or PD-98059 (an inhibitor of ERK1/2) resulted in the synergistic reduction of COX-2 expression and increase of caspase-3 expression, a decreased number of apoptotic cells, along with decreased cell viability. Combined treatment with NS-398 (an inhibitor of COX-2) and NaHS also resulted in the synergistic increase of caspase-3, a decreased in the number of apoptotic cells and the decrease in cell viability. The findings of the present study provide novel evidence that p38MAPK/ERK1/2-COX-2 pathways are involved in NaHS-induced cancer cell proliferation and anti-apoptosis in C6glioma cells.