Abstract 431: Laminin-511 regulates melanoma cell function and tumor growth

Laminin family proteins are major non-collagenous components of basement membranes and have been found to be involved in modulating cell behavior. Laminin-511, composed of α5, β1, γ1 chains, is a major component of basement membrane of epithelia and blood vessels. Our lab has recently found increased expression of laminin-511 in malignant tumors. It has been found that tumor cells can synthesize and secrete laminin matrix to modify cellular environment and promote cell invasion. To explore the potential role of laminin-511 in melanoma, we blocked the expression of laminin-511 in human melanoma cell line SK-Mel-28 using RNA silencing strategy by transducing cells with lentiviral vector carrying laminin α5 chain specific shRNA (Lenti-Lα5 shRNA). Our data demonstrated that blocking the expression of laminin-511 significantly inhibited melanoma cell proliferation, attachment, migration and invasion in vitro, as well as tumor growth in vivo. In melanoma cells transduced with Lenti-Lα5 shRNA, compared with control melanoma cells, in cell proliferation analysis the total viable cells were 34.49% and 26.28% reduced on day 3 and day 5, respectively; in cell attachment assay the cell binding ability was decreased by 36.4%, 37.65% and 36.2% at 15, 30 and 60 minutes, respectively; in a chamber migration assay the cell migratory rate was dramatically down 90% at 24 hours; and in a Metrigel invasion assay the cell invasive capacity was markedly reduced by 89% at 24 hours. Furthermore, blocking laminin-511 expression significantly reduced tumor growth in vivo in nude mice. 18 tumors grew out of 20 injections with average volume 206 mm 3 8 weeks post injection in cells tranduced with Lenti-Lα5 shRNA compared with 20 tumors out of 20 injections with average volume 590 mm 3 in control cells. These findings revealed that laminin-511 plays important roles in melanoma cell function and tumor growth. In addition, our results strongly indicate laminin-511 a potential target for melanoma therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 431. doi:10.1158/1538-7445.AM2011-431