Abstract 1383: Phenotype-based development of novel therapies for the treatment of colorectal cancer
Authors: Clare T. Butler, Adrian Murphy, William M. Gallagher, Jacintha O'Sullivan, Breandán Kennedy
Journal: Cancer Research (2015)

Abstract Introduction: Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Treatment of late stage CRC using Bevacizumab®, a targeted anti-VEGF, produces insufficient patient response rates and acquired tumour resistance. There is a clinical need for development of improved treatment options. Materials and Methods: Previously, anti-angiogenic screens in Tgfli1:EGFP zebrafish identified Quininib, a small molecule drug as effective as Bevacizumab®at reducing tumour volume in vivo and which reduces tumour CD31 expression in xenografted mice. Here, structural analogues of Quininib were synthesised to identify novel chemical entities with higher anti-angiogenic and anti-inflammatory efficacy. Analogues were examined for anti-angiogenic effects in the zebrafish intersegmental-vessel assay. Hits were progressed for safety analysis in cytotoxic assays, anti-angiogenic efficacy in aortic explants, and effects on cell proliferation and tubule formation using HT29_Luc2 and HMEC cells. Leads were then tested in ex vivo human CRC tumour explants to determine effects on angiogenic and inflammatory factor secretion. A CRC-specific murine xeongraft model was created by subcutaneous injection of HT29_Luc2 cells for anti-tumorigenic analysis of the Quininib analogues. Results and Discussion: Five out of 12 drug candidates (CTB_1, CTB_2, WP_1, WP_2 and WP_11) reduced developmental angiogenesis in fli1:EGFP zebrafish significantly more than Quininib (98% vs 67%, ***P&amp;lt;0.01). These analogues were well-tolerated in human endothelial and CRC cell cytotoxic assays and were more effective than Quininib at reducing tubule formation and angiogenic factor secretion in HMEC cells. Two analogues reduced aortic ring vessel sprouting equally or more effectively than Quininib. Preliminary data suggests that certain analogues can reduce inflammatory and angiogenic factor secretion from ex vivo human CRC explants more so than Quininib. We successfully established a CRC-specific murine tumour xenograft model. Using a ranking efficacy table, we chose analogues to analyse their anti-tumorigenic and anti-metastatic effects, by i/p injection in an optimised model of HT29_Luc2-CRC tumourigenesis in Balb/c nude mice. Conclusion: We identified 5 analogues which are significantly more effective than Quininib within in vitro and ex vivo models of inflammation and angiogenesis. Our highest ranking analogue will be tested in murine xenografts to determine effects on tumour burden and metastasis. Citation Format: Clare T. Butler, Adrian Murphy, William M. Gallagher, Jacintha O'Sullivan, Breandán Kennedy. Phenotype-based development of novel therapies for the treatment of colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1383. doi:10.1158/1538-7445.AM2015-1383