A Synthetic Polyvalent Ligand for alpha 5 beta 1 Integrin Activates Components of the Urothelial Carcinoma Cell Response to Bacillus Calmette-Guerin

作者：Chen Fanghong; Zhang Guangjian; Cao YanLi; Wakim Bassam; See William A^*

来源：Journal of Urology, 2013, 189(3): 1104-1109.

DOI：10.1016/j.juro.2012.08.218

• urinary bladder
• urothelium
• integrin alpha5beta1
• carcinoma
• BCG vaccine

Purpose: Prior study has shown that bacillus Calmette-Guerin binds to and cross-links alpha 5 beta 1 integrins present on the surface of urothelial carcinoma cells. Antibody mediated cross-linking of alpha 5 beta 1 integrins can reproduce signal transduction, gene transactivation and phenotypic changes, similar to those observed in response to bacillus Calmette-Guerin. We evaluated the effect of a synthetic polyvalent ligand for alpha 5 beta 1 on these elements of the tumor response to bacillus Calmette-Guerin. Materials and Methods: The consensus alpha 5 beta 1 integrin binding tripeptide RGD was linked to a MAP8 backbone to result in an octavalent construct targeting alpha 5 beta 1 integrin. RGD-MAP8 was used to determine its effect on signaling pathway activation (nuclear factor-kappa B, NRF2 and CEBP), gene expression (p21, interleukin-6 and 8, CXCL1, CXCL2 and CCL20) and cytotoxicity (trypan blue exclusion and HMGB1 release) in human urothelial carcinoma cells. Results were compared to those of treatment with bacillus Calmette-Guerin or the missense peptide GRD-MAP8. Results: The RDG-MAP8 construct significantly increased nuclear factor-kappa B signaling and p21 expression relative to controls. Compared to bacillus Calmette-Guerin treatment, only p21 expression was comparable for cells treated with RGD-MAP8, averaging 70% of bacillus Calmette-Guerin induced expression. RGD-MAP8 failed to have a significant effect on CEBP or NRF2 activation, gene expression or cell viability. Conclusions: Intracellular signaling, gene transactivation and phenotypic changes in response to RGD-MAP8 were qualitatively and quantitatively different than those observed in response to bacillus Calmette-Guerin. Results suggest that while alpha 5 beta 1 integrin cross-linking contributes to the bacillus Calmette-Guerin response, it alone is insufficient to duplicate the full spectrum of bacillus Calmette-Guerin induced changes in urothelial carcinoma cell biology.

• 出版日期2013-3