[Rapamycin enhances inhibitory effect of RSL3 on proliferation, invasion and migration of testicular cancer I-10 cells in vitro]

OBJECTIVE

To investigate the effect of rapamycin for enhancing the inhibitory effect of RSL3 on proliferation, invasion and migration of testicular cancer I-10 cells in vitro.

METHODS

I-10 cells treated with 0-16 μmol/L RSL3 (Type Ⅱ) either alone or in combination with 16 μmol/L rapamycin (RAPA) were examined for changes in proliferation using MTT assay and colonyforming assay, and the changes in cell migration and invasion abilities were detected with wounding-healing assay and Transwell assay. The changes in the levels of lipid reactive oxygen species in the treated cells were detected using flow cytometry. GSH and MDA contents in the cells were detected using commercial detection kits, and GPX4 protein expression level was determined with Western blotting.

RESULTS

The cytotoxic effect of RSL3 increased dose-dependently in I-10 cells, and the combined treatment with rapamycin further enhanced its cytotoxicity. Treatment of I-10 cells with RSL3 alone significantly decreased cell colony numbers (P < 0.05), wounding-healing rates (P < 0.01), and invasion and migration cell numbers (P < 0.05), increased lipid reactive oxygen species level and MDA content (P < 0.05), and lowered GSH content and expression level of GPX4 protein in the cells (P < 0.01). The inhibitory effects of RSL3 were significantly enhanced by co-treatment of the cells with rapamycin (P < 0.05 or 0.01).

CONCLUSION

Rapamycin enhances the inhibitory effect of RSL3 on proliferation, invasion and migration of I-10 cells by enhancing RSL3-mediated cell ferroptosis.

[Carbenoxolone enhances inhibitory effect of RSL3 against cisplatin-resistant testicular cancer cells by promoting ferroptosis]

OBJECTIVE

To investigate the inhibitory effect of RSL3 on the proliferation, invasion and migration of cisplatinresistant testicular cancer cells (I-10/DDP) and the effect of carbenoxolone on the activity of RSL3 against testicular cancer.

METHODS

MTT assay was used to evaluate the survival rate of I-10/DDP cells following treatment with RSL3 (1, 2, 4, 8, 16 or 32 μmol/L) alone or in combination with carbenoxolone (100 μmol/L) or after treatment with Fer-1 (2 μmol/L), RSL3 (4 μmol/L), RSL3+Fer-1, RSL3+carbenoxolone (100 μmol/L), or RSL3+Fer-1+carbenoxolone. Colony formation assay was used to assess the proliferation ability of the treated cells; wounding-healing assay and Transwell assay were used to assess the invasion and migration ability of the cells. The expression of GPX4 was detected using Western blotting, the levels of lipid ROS were detected using C11 BODIPY 581/591 fluorescent probe, and the levels of Fe²⁺ were determined with FerroOrange fluorescent probe.

RESULTS

RSL3 dose-dependently decreased the survival rate of I-10/DDP cells, and the combined treatment with 2, 4, or 8 μmol/L RSL3 with carbenoxolone, as compared with RSL3 treatment alone, resulted in significant reduction of the cell survival rate. The combination with carbenoxolone significantly enhanced the inhibitory effect of RSL3 on colony formation, wound healing rate (P=0.005), invasion and migration of the cells (P < 0.001). Fer-1 obviously attenuated the inhibitory effects of RSL3 alone and its combination with carbenoxolone on I-10/DDP cells (P < 0.01). RSL3 treatment significantly decreased GPX4 expression (P=0.001) and increased lipid ROS level (P=0.001) and Fe²⁺ level in the cells, and these effects were further enhanced by the combined treatment with carbenoxolone (P < 0.01).

CONCLUSION

Carbenoxolone enhances the inhibitory effect of RSL3 on the proliferation, invasion and migration of cisplatin-resistant testicular cancer cells by promoting RSL3-induced ferroptosis.

[Inhibiting autophagy by silencing ATG5 and ATG7 enhances inhibitory effect of DDP on DDP-resistant I-10 testicular cancer cells]

OBJECTIVE

To observe the changes in autophagy of cisplatin-resistant I-10 testicular cancer cells (I-10/DDP cells) in response to cisplatin treatment and the effect of silencing ATG5 and ATG7 on autophagy and proliferation of cisplatin-treated cells.

OBJECTIVE

I-10/DDP cells treated with 15 μmol/L cisplatin for 12 h were examined for expressions of LC3 and p62 by Western blotting and for autophagy level through transmission electron microscopy and mCherry-GFP-LC3B. I-10/DDP cells were transfected with short hairpin RNAs shRNA-ATG5 or shRNA-ATG7 via Lipfectamine2000, the empty vector (NC group), or Lipfectamine2000 alone (blank control group), and the cellular expressions of ATG5 and ATG7 were detected with Western blotting. The transfected cells were treated with 15 μmol/L cisplatin for 12 h, after that the expressions of LC3 and p62 were detected with Western blotting. Transmission electron microscopy and mCherry-GFP-LC3B were used to detect autophagy level in the cells. MTT assay and colony-forming assay were performed to assess the cell survival fraction and colony formation ability of the treated cells, respectively.

OBJECTIVE

After cisplatin treatmert, the expression level of LC3 II increased significantly (P < 0.001), the expression level of p62 decreased (P < 0.05), and the number of autophagosomes increased in I-10/DDP cells. The cells transfected with shRNA-ATG5 or shRNA-ATG7 showed significantly decreased expressions of ATG5 or ATG7 (P=0.005 or P < 0.001). Cisplatin treatment of the transfected cells obviously reduced the cellular expression of LC3 II (P < 0.001), increased the expression of p62 (P < 0.001), and decreased the number of autophagosomes, cell survival fraction and colony formation ability of the cells (P < 0.001).

OBJECTIVE

Silencing ATG5 and ATG7 inhibits cisplatin-mediated autophagy and enhances the inhibitory effect of cisplatin on inhibiting cell proliferation.