Abstract 14: A new orally available drug for the treatment of metastatic cancers

Metastatic cancers account for the great majority of cancer deaths. We conducted a screen to indetify known drugs that selectively inhibit the viability of metastatic tumor cells. Results of the screen identified members of the FDA-approved benzimidazole methylcarbamate family (e.g. mebendazole (MBZ) and albendazole (ALB)) as potential therapies for metastatic disease. Earlier work also supports a role for this chemical family in the potential treatment of activity in multiple cancers, but progress has been stalled by their poor water solubility and poor bioavailability for systemic delivery to disseminated tumors. We therefore synthesized a novel compound (OBD9) containing the scaffold of MBZ coupled to an oxetane group to enhance aqueous solubility to 361 μM. OBD9 demonstrates significant cytotoxicity toward a variety of cancer cell types including colon, lung, and prostate cancers (IC50: 0.9-2 μM). In a mouse xenograft model of human A549 lung cancer cell line OBD9 dramatically inhibited the growth of established tumors at 30 or 90 μM without noticeable toxicity. In a mouse xenograft model using highly aggressive PCMLN3 prostate cancer cells, oral administration of OBD9 at 30 mg/kg also significantly repressed growth of established tumors with no visible toxicity. We have studied the working mechanisms behind OBD9 and found that the Wnt signaling pathway is suppressed by OBD9 treatment. Both qPCR and Western blot data suggest that the beta-catenin/TCF complex in the Wnt signaling pathway are inhibited by OBD9. Among the downstream targets of Wnt signaling pathway, the oncogene cMyc is also significantly decreased in different cancers including colon, lung and prostate cancer. Overall, our in vitro and in vivo data suggest that OBD9 potentially represents a novel therapeutic option for multiple cancers especially metastatic cancer through targeting Wnt signaling pathway and the downstream oncogene cMyc. Citation Format: Kun Zhou, Jae Eun Cheong, Michaela Zaffagni, Yingjie Xu, Lijun Sun, Bruce Zetter. A new orally available drug for the treatment of metastatic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 14.