Phospholipase-C gamma-1 (PLCγ-1) is critical in hepatocyte growth factor induced in vitro invasion and migration without affecting the growth of prostate cancer cells

Background: Phospholipase C gamma-1 (PLC gamma-1) is an intracellular signalling molecule regulating a number of biological processes including transporter mechanisms, transcription factors, and scaffolding proteins mediating cytoskeleton and membrane trafficking. Hepatocyte growth factor (HGF) is a pleiotrophic factor and a mediator of metastatic spread. This study sought to determine the effect of HGF on the invasive and migratory potential of prostate cancer cells targeted by a ribozyme transgene to PLC gamma-1. Methods: A ribozyme transgene consisting of hammerhead ribozyme and antisense specific to PLC gamma-1 was cloned into a PEF6 expression vector and transfected into PC-3 cells. RT-PCR and Western blotting confirmed knock down of PLC gamma-1. In vitro invasion and a cytodex-2 bead motility assays with in vitro and in vivo growth models were used to assess the impact of PLC gamma-1 manipulation. Results: PC-3 cells stably transfected with PLC gamma-1 ribozyme transgene (PC-3(Delta PLC)gamma) manifested a reduction of PLC gamma-1 expression at mRNA/protein levels. HGF/SF increased invasiveness (P < 0.01) and motility (P < 0.0001) of PC-3(WT) and PC-3(PEF6) cells. In contrast, PLC gamma-1 knock down PC-3(Delta PLC)gamma cells had reduced invasiveness (P < 0.05) and motility (P < 0.01) compared with PC-3(WT) and PC-3(PEF6) cells. Although there was a marginal change of cell growth in vitro, there was no difference in the rate of growth between PC-3(Delta PLC)gamma, PC-3(WT), and PC-3(PEF6) cells. Conclusion: Targeting PLC gamma-1 by way of a hammerhead ribozyme to PLC gamma-1 is an effective method in reducing invasive phenotype of prostate cancer. PLC gamma-1 is a signalling intermediate that has prime influence on HGF induced cellular invasion and migration without affecting the growth of the cells. (C) 2008 Elsevier Inc. All rights reserved.