PGRMC1-mediated autophagy decreases the sensitivity of hepatocellular carcinoma cells to 125I particle irradiation

Abstract

Objective To investigate the effect of progesterone receptor membrane component 1 (PGRMC1) mediated autophagy on the sensitivity of liver cancer cells to 125I particles irradiation. Methods Hepatoma cell lines Huh7 and LM3 were exposed to different doses (0, 2, 4, 6 and 8 Gy) of 125I particles, and cell autophagy was observed by transmission electron microscopy (TEM). Then, autophagy inhibitor chloroquine (CQ), agonist rapamycin (Rapa), and PGRMC1 inhibitor AG-205 were used respectively to verify that PGRMC1-mediated autophagy plays a key role in the sensitivity of hepatocellular carcinoma cells to 125I particle irradiation. Cell proliferation, colony formation and apoptosis were detected by CCK-8 assay, clonal formation test and flow cytometry, respectively. The expression levels of PGRMC1, microtubule-associated protein light chain 3-Ⅰ (LC3-Ⅰ), LC3-Ⅱ and p62 were detected by Western blotting. Results Different doses of 125I particles irradiation significantly decreased the proliferation and clonogenesis of Huh7 and LM3 cells (P < 0.05), and increased the apoptotic cells (P < 0.01), in a dose-dependent manner. Compared with the 0 Gy group, the ratio of LC3-Ⅱ/ LC3-Ⅰ in Huh7 and LM3 cells was obviously increased, and the expression of p62 was significantly down-regulated in the 6 Gy group. The proliferation capacity and clonal formation ability of Huh7 and LM3 cells were decreased significantly, and their apoptotic cells were increased notably in the 6 Gy+CQ group than the 6 Gy group, while the above results were on the contrary in the 6 Gy+Rapa group. The 6 Gy+AG205 group had notably decreased LC3-Ⅱ/LC3-Ⅰ ratio in the Huh7 and LM3 cells, up-regulated p62 expression, reduced cell proliferation capacity and clone formation ability, and enhanced cell apoptosis when compared with the 6 Gy group, and the above results of the 6 Gy+PGRMC1 group were opposite. Conclusion Increment of PGRMC1 induced by 125I irradiation can promote autophagy, increase the proliferation and clonogenesis, and reduce the apoptosis in hepatocellular carcinoma cells.

Keywords

• hepatoma cells
• pgrmc1
• radiation sensitivity
• 125i
• autophagy
• apoptosis