GRPR and neuroblastoma: Second, in two studies (194, 203), GRPR activation in various neuroblastoma cells (SK-N-SH, IMR-32, LAN-1) stimulated the expression of matrix metalloproteinase-2 (MMP-2); a decrease in the expression of the tissue inhibitor of MMP-2; and the upregulation of integrin alpha 2, alpha 3, and integrin beta 1 proteins, as well as their mRNA expression; and a reduction of the integrin beta 1 inhibited GRPR-stimulated cell migration.