Tumor cell invasion and metastasis are inter related proc esses associated with adhesion of tumor cells, hydrolysis of the extracellular matrix, cell mobility, and the regula tion and expression of metastasis related genes. Protein kinases are involved in all of the above mentioned proc esses. Protein kinase C, an important member of selleck bio the protein kinase family, is a calcium activated and phos pholipid dependent serine threonine protein kinase. PKC phosphorylates a number of substrates to mediate a series of physiological responses, including cell growth, prolifer ation, differentiation, apoptosis, and mobility. Fur thermore, PKC is also important for the maintenance of normal physiological functions of cells. It has been demonstrated that the PKC level, which is closely related to the invasiveness and metastasis of tumor cells, is enhanced in some tumors.

It was recently shown that the level of PKC is significantly higher in lung cancer tis sue when compared to healthy lung tissue, and its traffick ing to the cell membrane and the nuclei is also increased significantly. Moreover, examination of clinical sam ples showed Inhibitors,Modulators,Libraries that the levels of PKC protein correlated with lung cancer TNM staging. Higher PKC levels were seen in more advanced stages with higher metastatic and invasive capabilities. It has been suggested that the over expression of PKC and its cytomembrane transporta tion play a role in regulating the progress and metastasis of lung cancer cells Staurosporine is a potent inhibitor of PKC and many other kinases, including the tyrosine protein kinase.

It blocks the transfer of the phosphate ester from DNA to the activated tyrosine sites and directly inhibits the activity of topoisomerase II. It has been reported that stau rosporine can induce apoptosis of a Inhibitors,Modulators,Libraries variety of cells, including cardiac cells, oral squamous cell carcinoma cells, and fibroblasts. Therefore, staurosporine is widely Inhibitors,Modulators,Libraries used to study apoptosis and has become one of the most promising anti cancer drugs. Although staurosporine has been well studied Inhibitors,Modulators,Libraries in the context of apoptosis in cancer cells, not much information is available on the Inhibitors,Modulators,Libraries role of staurosporine on cell adhesion, mobility and invasion in lung cancer in the context of tumor metastasis. Based on the above information, we hypothesized that staurosporine mediated inhibition of PKC could affect the invasive and metastatic capabilities of lung tumor cells, exerting its anti tumor function through mecha nisms other than the induction of apoptosis.

In this study, we treated human lung adenocarcinoma A549 cells with staurosporine and investigated the relationship between staurosporine treatment and tumor cell adhesion, mobil ity, and invasiveness. We also studied the effect of stau rosporine on the levels of adhesion molecules, including integrin 1, E cadherin, LnR, and on the levels of proteo lytic enzymes MMP 9 selleck chemicals and uPA.