Dual effects of β3 integrin subunit expression on human pancreatic cancer models.

BACKGROUND: Pancreatic cancer, the fifth leading cause of adult cancer death in Western countries, lacks early detection, and displays significant dissemination ability. Accumulating evidence shows that integrin-mediated cell attachment to the extracellular matrix induces phenotypes and signaling pathways that regulate tumor cell growth and migration.
METHODS: In view of these findings, we examined the role of β(3) in pancreatic cancer by generating two stable β(3)-expressing pancreatic human cell lines and characterizing their behavior in vitro and in vivo.
RESULTS: Transduction of β(3) selectively augmented the functional membrane α(v)β(3) integrin levels, as evident from the enhanced adhesion and migration abilities related to active Rho GTPases. No effects on in vitro anchorage-dependent growth, but higher anoikis were detected in β(3)-overexpressing cells. Moreover, tumors expressing β(3) displayed reduced growth. Interestingly, treatment of mice with an α(v)-blocking antibody inhibited the growth of β(3)-expressing tumors to a higher extent.
CONCLUSIONS: Our results collectively support the hypothesis that α(v)β(3) integrin has dual actions depending on the cell environment, and provide additional evidence on the role of integrins in pancreatic cancer, which should eventually aid in improving prediction of the effects of therapies addressed to modulate integrin activities in these tumors.