Carbenoxolone enhances inhibitory effect of RSL3 against cisplatin-resistant testicular cancer cells by promoting ferroptosis / 南方医科大学学报

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.

Renal humoral modulation of skeletal muscle tone in mice: implications for 'the pulmonary-renal cascade'.

The pulmonary-renal cascade may regulate the respiration and skeletal muscle contractility. To evaluate this working hypothetical model, we conducted experiments to ascertain the skeletal muscle tone of the Swiss mice (20-35 g). The animals were evaluated for their skeletal muscle tone via several techniques i.e. inclined plane test, grip strength test and swim test. Groups of mice (n=6) were pre-treated with mefenamic acid (60 mg/kg, i.p), carbenoxolone (100 mg/kg i.p) or vehicle only 15 minutes before the treatment with heparin (500 U/kg, i.v), urokinase (5500 U/kg, i.v) and erythropoietin (150 U/kg, i.v). Heparin potentiated the loss of skeletal muscle tone induced by mefenamic acid and carbenoxolone while urokinase & erythropoietin significantly enhanced the skeletal muscle tone as evaluated by all or one of the tests. Other groups of mice (n=6) were pretreated with mefenamic acid (1 mg i.c.v), carbenoxolone (160 microg i.c.v) or minoxidil (30 microg i.c.v) and the effects of heparin & urokinase and erythropoietin on skeletal muscle tone were evaluated. To study the effects of heparin and urokinase on nerve regeneration, two groups of mice underwent a sham and sciatic nerve crush procedure. The mice treated with urokinase recovered much faster as compared to those treated with heparin or saline. These experimental results suggest that gap junction blockers and potassium channel openers interact with heparin, urokinase and erythropoietin to control the skeletal muscle tone.