3696

ITGB8

integrin, beta 8;ITGB8;integrin, beta 8

integrin beta-8

7p21.1

protein-coding

Lung cancer is the leading cause of cancer death in the world and metastasis is an essential aspect of lung cancer progression. ITGB8 has been implicated in metastasis of human tumors. However, the molecular mechanism by which ITGB8 is involved in tumor metastasis is still unclear. In this study, we compared the gene expression profiles of human lung cancer cell lines A549 and PC9 by ITGB8 gene silencing with that of parent cells and negative control cells to comprehensively investigate ITGB8-mediated changes with respect to the metastatic potential and gene expression of human lung cancer cell lines. Our results showed that ITGB8 silencing cells exhibited significant cell cycle arrest and less adhesion and invasion abilities. We confirmed by Western blot, ELISA, and real-time PCR that the expression of metastasis-related genes CXCL1, CXCL2, CXCL5, MMP-2, and MMP-9 were significantly decreased while that of E-Cadherin and cystatin B were dramatically increased in A549- and PC9-ITGB8 silencing cells. Furthermore, silencing of ITGB8 caused Snail and NF-kappaB transcriptional activation, and MEK and Akt phosphorylation level changes in lung cancer cell lines. Our results indicated that ITGB8 may play an important role in metastasis of human lung cancer cells. The ITGB8 silencing may change the lung cancer cells to a less invasive phenotype through alteration in the expression of metastasis-related genes.

tumor metastasis is a multistep pathological process involved in the final phase of tumor development. During this process, epithelium-derived tumor cells undergo fibroblast-like transformation, referred to as epithelial-mesenchymal transition (EMT), which contributes to aggressive behavior of tumors. We identify periostin, a mesenchyme-specific gene product, as a contributor to EMT and metastatic potential. Stable expression of a periostin transgene in tumorigenic but non-metastatic 293T cells caused cells to undergo fibroblast-like transformation accompanied by increased expressions of vimentin, epidermal growth factor receptor (EGFR), and matrix metalloproteinase-9. The cells expressing ectopic periostin increased cell migration, invasion, and adhesion by 2-9-fold. Invasive characteristics required signaling through integrin alpha(v)beta5 and EGFR. In addition, periostin-engineered 293T cells formed metastases in immunodeficient mice following either cardiac inoculation or injection into mammary fat pad. These data demonstrate an active role for periostin in EMT and metastasis that requires cross-talk between integrin and EGFR signaling pathways.