Abstract B46: Tetra-O-methyl nordihydroguaiaretic acid broadly suppresses cancer metabolism and synergistically induces strong anticancer activity in combination with Etoposide, Rapamycin and UCN-01

We have been developing an anticancer drug, Tetra-O-methyl nordihydroguaiaretic acid (M4N), for many years. M4N is currently in Phase I/II clinical trials in patients with various advanced cancer. The results of these clinical trials so far indicate that M4N has a certain degree of anticancer activity, but was unable to induce remission in any of these patients with advanced cancers. One of the most frequently attempted strategy to increase anticancer efficacy of chemotherapy drugs is combination treatment with one or more appropriately selected drugs. An important finding from the clinical trials with M4N is that the toxicity of the drug was very low. Patients were able to tolerate high doses of M4N with minimal side-effects, which make this drug very suitable for being use in multidrug treatments (for instance the LD50 of M4N for mice is greater than 1000mg/kg while that of NDGA, a parental compound for M4N, is only 75mg/kg). In this study the ability of M4N to induce rapid cell death in combination with Etoposide, Rapamycin, or UCN-01 was examined in LNCaP cells, both in cell culture and animal experiments. Mice treated with M4N drug combinations with either Etoposide or Rapamycin showed no evidence of tumor and had a 100% survival rate 100 days after tumor implantation. By comparison all other vehicles or single drug treated mice failed to survive longer than 30 days after implantation. This synergistic improvement of anticancer effect was also confirmed in more than 20 cancer cell lines including several pancreatic cell lines (AsPC-1, CAK24, Panc1.98, and Panc215). In LNCaP cells, M4N was found to reduce cellular ATP content, and suppress NDUFS1 expression while inducing hyperpolarization of mitochondrial membrane potential. M4N-treated cells lacked autophagy with reduced expression of BNIP3 and ATG5. To understand the mechanisms of this anticancer activity of M4N, the effect of this drug on three cancer cell lines (LNCaP prostatic, AsPC-1 pancreatic, and L428 leukemic cells) was further examined via transcriptome and metabolomics analyses. Metabolomic results showed that there were reductions of 26 metabolites essential for energy generation and/or production of cellular components in common with these three cell lines following 8 hours of M4N treatment. Deep RNA sequencing analysis demonstrated that there were sixteen genes whose expressions were found to be modulated following 6 hours of M4N treatment similarly in these three cell lines. Six out of these 16 genes were functionally related to the 26 metabolites described above. One of these up-regulated genes encodes for CHAC1, a key enzyme affecting the stress pathways through its degradation of glutathione. In fact M4N was found to suppress glutathione content and induce reactive oxygen species production. The data overall indicate that M4N has profound specific negative impacts on a wide range of cancer metabolisms supporting the use of M4N combination treatments for cancers of various origins including pancreas. Citation Format: Kotohiko Kimura, Ru Chih C. Huang.{Authors}. Tetra-O-methyl nordihydroguaiaretic acid broadly suppresses cancer metabolism and synergistically induces strong anticancer activity in combination with Etoposide, Rapamycin and UCN-01. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B46.