Background: Protein Kinase C (PKC) is one of the key kinases in the cell signal transduction passway. There are more reports about it's ability on cell proliferation, but fewer on invasion and metastasis in the past; and it's mechanisms are unclear. The aim of this study is to analyze the variation of intracellular distribution and translocation of the protein kinase C alpha among human high-metastatic large cell lung cancer cell line with different metastasis potential,in order to investigate the correlation between the lung carcinoma invasion and metastasis and the PKC isoforms.
Methods: Using Western blot and laser scanning confocal microscope (LSCM) method. The distribution of PKC alpha in cytosol and plasma membrane and translocation were detected among different metastatic potential human pulmonary carcinoma cells L9981, L9981-pLXSN and L9981-nm23-H1 before and after treatment with PKC inhibitor Calphostin C, by Western blot and LSCM.
Results: PKC alpha in L9981 and L9981- pLXSN was mainly expressed on membrane, which was remarkably higher than those in L9981-nm23-H1 cell line (P =0.001); while expression of PKC alpha in cytoslol in L9981 and L9981-pLXSN cell lines, was lower than those in L9981-nm23-H1 cell line (P <0.001). The expression of PKC alpha in cytosol in L9981-nm23-H1 cell line was remarkably higher than those in L9981 and L9981-pLXSN cell lines (P <0.001), while expression of PKC alpha in plasma membrane in L9981-nm23-H1 cell line, was significantly lower than those in L9981 and L9981- pLXSN cell lines (P =0.001). PKC alpha is mainly located in nucleus and perinucleus in L9981 and L9981-pLXSN cells, which was in active status, In L9981-nm23-H1 cell line, PKC alpha is mainly located in soluble cytosolic section, which was in inactive status. After treated with PKC inhibitor Calphostin C, the expression of PKC alpha in membrane in L9981, L9981-pLXSN and L9981-nm23-H1 was downregulated, and PKC alpha were observed mainly located in cytosolic site in all the three cell lines, which was mainly in inactive status.
Conclusions: The study suggests that PKC isoforms is closely correlated with human lung cancer invasion and metastasis.