Hydrogen gas represses the progression of lung cancer via downregulating CD47

Hydrogen gas (H2) has been identified to play an anti-tumor role in several kinds of cancers, but the molecular mechanisms remains largely unknown. In our previous study, our project group found that H2 could decreased the expression of CD47 in lung cancer A549 cells via using the next generation sequencing, indicating that CD47 might be involved in H2-mediated lung cancer repression. Therefore, this study aimed to explore the effects of CD47 on H2-induced lung cancer repression. Western blotting and RT-PCR assays were used to detect the levels of proteins and mRNAs, respectively. Cell proliferation, invasion, migration and apoptosis were detected by using the CCK-8, Transwell chambers, wound healing and flow cytometry assays, respectively. The results showed that H2 treatment caused decreases in the expression levels of CD47 and cell division control protein 42 (CDC42) in a dose-dependent manner. Upregulation of CD47 abolished H2 roles in promoting lung cancer cell apoptosis and repressing cell growth, invasion and migration in both A549 and H1975 cell lines. However, knockdown of CD47 enhanced H2 role in lung cancer inhibition. Moreover, we also observed that H2 treatment induced obvious inhibitions in the expression levels of CDC42 and CD47 in mice tumor tissues, as well as reinforced macrophage-mediated phagocytosis in A549 and H1975 cells. In conclusion, the current study reveals that H2 inhibits the progression of lung cancer via downregulating CD47, which might be a potent method for lung cancer treatment.

Suppression of autophagy facilitates hydrogen gas-mediated lung cancer cell apoptosis

Our previous study found that hydrogen gas (H2) could efficiently inhibit lung cancer progression; however, the underlying mechanisms still remains to be elucidated. The present study aimed to explore the roles of H2 in lung cancer cell autophagy, and reveal the effects of autophagy on H2-mediated lung cancer cell apoptosis and the underlying mechanisms. The expression levels of proteins associated with cell apoptosis and autophagy were detected using western blot analysis. Cell autophagy was inhibited by 3-methyladenine treatment or Beclin1 downregulation, while rapamycin was used to induce autophagy. Cell growth and apoptosis were detected using the Cell Counting Kit-8 and flow cytometry assays, respectively. The results demonstrated that cell apoptosis and autophagy were significantly enhanced in the A549 and H1975 lung cancer cell lines treated with H2. However, autophagy enhancement weakened H2 roles in promoting cell apoptosis and vice versa. In addition, it was found that H2 treatment induced marked decreases in the protein expression levels of phosphorylated STAT3 and Bcl2, and overexpression of STAT3 abolished H2 roles in promoting cell apoptosis and autophagy. Overall, the present study revealed that H2 can promote lung cancer cell apoptosis and autophagy via inhibiting the activation of STAT3/Bcl2 signaling and suppression of autophagy can enhance H2 roles in promoting lung cancer cell apoptosis.