Background & objective: Phospholipase C-gamma 1 (PLC-gamma1) is a vital signal transducer in transmembrane signaling, which regulates cell proliferation and apoptosis. It is overexpressed in many cancers, such as colorectal cancer, which indicates that it is closely related to the genesis and development of tumors. This study was to explore the effects of blocking PLC-gamma1 signaling pathway on the proliferation and apoptosis of human colorectal cancer cell line LoVo, and investigate the signaling mechanisms.
Methods: LoVo cells were treated with PLC-gamma1-specific chemical blocking agent U73122. Cell proliferation was examined by cell counting, MTT assay, and flow cytometry (FCM). Cell apoptosis was observed under a microscope, and measured by agarose gel electrophoresis and FCM with PI simple staining. The expression of hot shock protein 70(HSP70) and Caspase-3 in LoVo cells were detected by Western blot.
Results: The proliferation of LoVo cells was inhibited after blocking PLC-gamma1 signaling pathway and the effect was enhanced along with the increasing concentration of U73122. The inhibition rate reached 35% and 45% when treated with 10 micromol/L U73122 for 24 h and 48 h respectively. After blocking PLC-gamma1 signaling pathway, the G1 phase proportion of LoVo cells was increased while the S phase proportion was decreasedû no apoptosis-specific cell shrinkage was found under a light microscope, and no apoptosis-specific DNA ladder was found by agarose gel electrophoresisû no activated Caspase-3 was detected by Western blot, while increased expression of HSP70 was detected.
Conclusions: Blocking PLC-gamma1 signaling pathway can inhibit the proliferation and cell cycle progress of LoVo cells, which may be due to the up-regulated expression of HSP70. PLC-gamma1 is not a vital signal molecule regulating the apoptosis of LoVo cells.