Abstract 1856: Adaptation to dopamine impairs the anti-cancer effect of ONC201 and ONC206

Abstract ONC201 (originally discovered as TRAIL-Inducing Compound #10 or TIC10) and analogue ONC206 have been found to induce an integrated stress response with suggested primary targets and mechanisms involving agonist activity against mitochondrial ClpP and antagonism of dopamine receptors D2/3 (DRD2/3). We hypothesized that dopamine, the agonist of DRD2, may compete with ONC201 or ONC206 for DRD2/3 and impair the anti-cancer effect of ONC201 or ONC206. We therefore pre-treated cancer cells from different tissue origins including breast cancer, pancreatic cancer, colorectal cancer, lung cancer, GBM, and DIPG with dopamine for 12 hours, 24 hours or 48 hours, respectively, followed by treatment of ONC201 or ONC206 for 72hours. Cell viability was determined by the CellTiter Glo assay. Single treatment with dopamine did not increase cell viability. We observed that 48 hours of pre-treatment with dopamine at 50 μM, 100 μM or 200 μM impaired the cell viability suppression effect of ONC201 at 4 μM and 8 μM, while ONC206 at 0.5 μM, 1 μM and 2 μM led to similar protection for loss of cell viability in pancreatic cancer cells. The impairment of the anti-cancer effect by dopamine was also observed in colorectal cancer cells with 48 hours pre-treatment with dopamine at 50 μM, 100 μM, 200 μM or 400 μM and treatment with ONC201 at 4 μM and 8 μM, or ONC206 at 0.5 μM, 1 μM, or 2 μM. In addition, we treated pancreatic cancer and colorectal cancer cells with ONC212 after 48 hours pre-treatment with dopamine and observed a similar impairment of the anti-cancer effect, even though ONC212 is not a DRD2 antagonist. We pre-treated pancreatic cancer and colorectal cancer cells with specific DRD2 agonist, sumanirole, for 48 hours followed by treatment of ONC201, ONC206, or ONC212 for 72 hours, and no impairment was seen. We pre-treated multiple cancer cell lines with 2 μM or 10 μM dopamine for one week followed by ONC201, ONC206, or ONC212 treatment and performed colony assays. Pre-treatment with dopamine at 10 μM impaired the anti-cancer effect of ONC201 or ONC206 in pancreatic cancer. Pre-treatment with dopamine at 2 μM or 10 μM impaired the anti-tumor effect of ONC201 in GBM cells. By contrast to the cell viability result, no impairment of ONC212 effect from dopamine was seen in pancreatic cancer cells. Western blotting was conducted to investigate whether dopamine pre-treatment impacted signaling pathways reported to be affected by ONC201. Dopamine pre-treatment did not impact changes induced by ONC201 in ATF4, CHOP, DR5, ClpX, clpP, pERK, pAkt and pS6. We are pursuing whether the protective effect of dopamine is due to the agonism of DRD2 or alternative pro-survival mechanisms. Citation Format: Yiqun Zhang, Wafik S. El-Deiry. Adaptation to dopamine impairs the anti-cancer effect of ONC201 and ONC206 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1856.