Abstract C33: Effects of curcumin on pancreatic ductal adenocarcinoma

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Abstract Without an early method of diagnosis or effective treatment plan, the prognosis for pancreatic ductal adenocarcinoma (PDAC) is grim, which begs for the development of additional treatment options. The plant-derived chemical, curcumin, has recently shown some promise as a potential therapy when tested in xenograft models of PDAC, glioblastoma, lung, breast, cervical, and colon tumors and is currently being tested in early clinical trials of certain cancers. However, efficacy studies against PDAC have not included preclinical mouse models with an intact immune system. To address the potential complication of a fully functional immune system on curcumin effectiveness, we assessed the effects of curcumin on murine PDAC cell lines both in vitro and in vivo. Murine PDAC lines were previously derived from genetically engineered KrasG12D; Trp53R172H; Pdx-1 Cre (KPC) mice, which spontaneously produce metastatic PDAC that closely mimics human disease. The dose- and time-dependent toxicity of curcumin was assessed using various cell lines in vitro, and our findings support previously published results. To assess effectiveness in vivo, tumor cells were implanted subcutaneously into syngeneic, C57Bl/6J mice. Once tumors were established, curcumin (or vehicle alone) was administered via intraperitoneal (i.p.) or intratumoral injection. Treatment efficacy was assessed by measuring tumor growth and the overall survival of mice. We found that curcumin treatment had no impact on tumor growth or overall survival of immunocompetent mice. To circumvent potential solubility issues common to curcumin and illustrate the importance of the immune system in treatment resistance, we repeated our in vivo studies using curcumin encapsulated in liposomes. In addition, we used T cell-depleting antibodies for a subset of mice to mimic athymic mice used in previously published xenograft models. T-cell depletion was verified prior to tumor cell implantation by flow cytometry. Once tumors were established, liposomal curcumin or mock treatment was administered via i.p. injection. For T cell-depleted mice, we found that treatment with liposomal curcumin stalled tumor growth and increased overall survival compared to mock treated mice. For T cell-replete mice, we found that treatment with liposomal curcumin had no impact on tumor growth or overall survival compared to mock treated mice, which agrees with our findings. Taken together, our data suggest that the presence of T cells causes a difference in responsiveness to curcumin in vivo. This finding warrants additional studies in order to understand this mechanism and enhance its potential success in the clinic. Citation Format: Adrianna M. Vaskas, Joseph A. Fraietta, Kristen B. Long. Effects of curcumin on pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C33.