Autophagy Regulated By PLCγ1 Leads To Death In Lung Adenocarcinoma Cells

"Targeting autophagy" is a potential approach for cance therapy.Phospholipase C gamma 1(PLCγ1)plays an important role in tumor development.Our previous studies in colon and hepatoma carcinoma cells indicated that PLCyl playing an important role in the occurrence and development of tumors was involved in autophagy induction.However,the specific role of PLCγ1 in lung adenocarcinoma and whether to regulate autophagy remain unclear.In this study,the expression of PLCγ1 in human lung adenocarcinoma was detected using immunohistochemistry.After lung adenocarcinoma A549 cells were treated with PLCγ1 inhibitor or transduced with shRNA/PLCγ1,the cell viability and growth were measured with MTT and standard cell colony formation assay,respectively,followed by the detection of cell metastasis,including the measurement of MMP2 and MMP9 mRNA levels by RT-PCR and the migration ability by Transwell assay.Meanwhile,autophagy biomarkers,relative signal molecules,and autophagsome were detected with Western Blot analysis,immunofluorescence assay,and transmission electron microscopy,respectively.Furthermore,autophagy biomarkers in A549 cells in response to autophagy inhibitor,CQ were detected with western blot analysis.Subsequently,the effect and regulatory mechanism of autophagy regulated by PLCγ1 on cell physiological function were investigated.The results showed that PLCγ1 had a higher expression in human lung adenocarcinoma tissue.The percentage of PLCγ1 expression in human lung adenocarcinoma specimens with regional lymph node metastasis(74%)was more than non-metastatic specimens(48%).The inhibition of PLCγ1 blocked partly cell proliferation and metastasis in A549 cells.PLCγ1 inhibition induced autophagy in A549 cells,in which AMPK,mTOR and ERK were involved.Interestingly,Autophagy regulated by PLCγ1 did not promote cell survival that was generally accepted by many researchers,but led to autophagic cell death.Therefore,we suggested that autophagic cell death by PLC yl-dependent autophagy might contribute to the suppression of cell proliferation and metastasis by PLCγ1 inhibition,with the implication that the enhancement of autophagy regulated by PLCyl could be a potential approach to promote drug sensitivity in cancer cells.