| Background and Object Lung Cancer is one of the most malignant cancers threatening people's health and life and one of the most rapid increasing cancers both in morbidity and mortality, and it is also one of the most close cancer between incidence and mortality. The cure rate of lung cancer is only 10%~15% and 90% of lung cancer dead of cancer metastasis. Tumor metastasis is not only the malignant marker and characteristics of lung cancer, but also the main cause of failure to cure and lose their life of the patients with lung cancer. Therefore, to study and illuminate the molecular mechanisms of lung cancer metastasis, to explore the molecular targets reserving or inhibiting lung cancer metastasis and to develop molecular target drugs for treating lung cancer metastasis are the future key direction and key projects in lung cancer fields. And it is also the hope that human being finally overcome lung cancer.Our research group led by Dr. Zhou Qinghua keep on studing in this area for a long time. In 1998, Dr. Zhou Qinghua first hopothesized that nm23-H1 gene may be an upstream key regulatory gene of "lung cancer metastatic suppressive cascade", and it can regulate the downstream metatasis-related genes to inhibit or reverse tumor metastasis phenotype of lung cancer. Our group established a human high-metastatic large cell lung cancer cell line with deletion of nm23-H1 gene (L9981), a human high-metastatic lung cell lung cancer cell line transtectcd with vector pLXSN (L9981-pLXSN) and a human high-metastatic large cell lung cancer cell line transfectd with wild nm23-H1 cDNA (L9981-nm23-H1). It has been proved that transfection of nm23-H1 gene could reverse the malignant and metatatic phenotype of human high-metastatic large cell lung cancer cell line L9981 in vivo and in vitro experiments, and that nm23-H1 gene inhibited and reversed tumor metastasis of L9981 lung cancer cell line through regulating signal transduction pathway of ras PKC, PAK and wnt. The aim of this study is to explore the molecular mechanisms which nm23-H1 gene regulate FAK signal transduction pathway and reverse metastatic phenotype of L9981 lung cancer cell line based on our previous studies.Method In this study, the expression and difference of total FAK protein and Tyr 393 FAK were detected in human high metatatic large cell lung cacner cell line L9981 and human low-metastatic large cell lung cancer cell line NL9980 by Western blot; the expession and difference of total FAK protein and Tyr 393 FAK were also determined in the L998K 19981-pLXSN and L9981-nm23-H1 lung cancer cell lines by Western blot; The invasion and migration of lung cancer cells were detected in the L9981, L9981-pLXSNand L9981-nm23-Hi lung cancer cell lines by Boyden chamber and migration test; The cyto- skeleton and expression of the cytoskeleton-related genes were detected in the L9981, L9981-pLXSN and L9981-nm23-Hi lung cancer cell lines by FACS.Results The results first showed in the world as follows.1. No significant difference of total FAK protein expression was observed between L9981 and NL9981 lung cancer cell line (P>0.05).2. The expressive level of Tyr 397 FAK protein in the L9981 cell line was remarkably higher than that in the NL9980 cell line (P<0.01).3. No significant difference of total FAK protein expression was existed among the L9981 > L9981-pLXSN and L9981-nm23-Hi lung cancer cell lines (P>0.05).4. The expressive level of Tyr 397 FAK protein in the L9981-nm23-Hi cell line transfected with nm23-Hi gene was significantly lower than that in L9981 and L9981-pLXSN cell line transfected with pLXSN vector (P<0.01), but no significant difference was found between the L9981 and L9981-pLXSN cell lines (P>0.05).5. A 130KD protein band was observed both in L9981-nm23-Hi and L9981-pLXSNcelllines.6. Transfection of nm23-Hi gene can remarkably decrease the refracteion projection and adhesion ability of the L9981 cell line.7. The vitro-invasion of L9981 lung cancer cell line was remarkably decreased after transfection with nm23-Hi gene.8. Transfection of nm23-Hi gene can significantly reduce the aggregation of microfilament, decrease the motility of the L9981 cell line.9. Transfection of nm23-Hi gene can remarkably downregulate the expression of integrin a v and a -actin in the L9981 cell line (P<0.0l).Conclusion: (1) human high-metastatic large cell lung cancer cell line L9981 exist overphosphoration of FAK, which may be related to the high metestatic characteristics of L9981 cell line. (2) Transfection of nm23-Hi gene can remarkably downregulate the expression of Tyr 397 FAK^ Integrin a v and a -actin of L9981 lung cancer cell line. (3) The molecular mechanisms which nm23-Hj gene inhibit and reverse the invasion and metastasis of the L9981 cell line may be related to the downregulation of Tyr 397 FAK, Integrin a v and a -actin expression. |
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