Formation and Anti-Tumor Activity of Uncommon In Vitro and In Vivo Metabolites of CPI-613, a Novel Anti-Tumor Compound That Selectively Alters Tumor Energy Metabolism

Abstract

CPI-613 is a novel anti-tumor compound with a mechanism-of-action which appears distinct from the current classes of anti-cancer agents used in the clinic. CPI-613 demonstrates both in vitro and in vivo anti-tumor activity. In vitro metabolic studies using liver S9 were performed which demonstrated that CPI-613 undergoes both phase 1 (oxidation) and phase 2 (glucuronidation) transformations. Its metabolic half-life varied between species and ranged from 8 minutes (Hanford minipig) to 47 minutes (CD-1 mouse). We performed metabolite mass assessments using selected in vitro incubation samples and demonstrated that +16 amu oxidation with and without +176 amu glucuronidation products were generated by human and animal liver S9. LC/MS/MS fragmentation patterns showed that an uncommon sulfoxide metabolite was formed and the O-glucuronidation occurred at the terminal carboxyl moiety. We observed that the +192 amu sulfoxide/glucuronide was generated only in human liver S9 and not by any of the other species tested. Synthetic metabolites were prepared and compared with the enzymatically-generated metabolites. Both the chromatographic retention times and the LC/MS/MS fragmentation patterns were similar, demonstrating that the synthetic metabolites were virtually identical to the S9-generated products. CYP450 reaction phenotyping and inhibition data both suggested that multiple CYP isozymes (2C8 and 3A4, along with minor contributions by 2C9 and 2C19) were involved in CPI-613 metabolism and sulfoxide formation. Plasma samples from human subjects dosed with CPI-613 also contained the sulfoxide ± glucuronide metabolites. These results show that the in vitro- and in vivo-generated phase 1 and phase 2 metabolites were in good agreement.

Pharmacologic Reprogramming Designed to Induce a Warburg Effect in Porcine Fetal Fibroblasts Alters Gene Expression and Quantities of Metabolites from Conditioned Media Without Increased Cell Proliferation

“…Previous CPI studies have focused on investigating the efficacy of this drug in anti-cancer treatment as a tumor-specific antimitochondrial mediator that has been tested in a number of cancerous cell lines as well as in vivo (Lee et al, 2011a , 2011b ; 2014 ; Pardee et al, 2014 ; Perera et al, 2012 ; Senzer et al, 2012 ; Zachar et al, 2011 ). A comparison of CPI treatment between cancerous and non-cancerous cell lines from lung, breast, and kidney demonstrated that CPI reduced cell survival in all of the cancerous lines compared to the non-cancerous lines, implying non-cancerous cells are less sensitive to CPI (Zachar et al, 2011 ).…”

Targeting Altered Energy Metabolism in Colorectal Cancer: Oncogenic Reprogramming, the Central Role of the TCA Cycle and Therapeutic Opportunities

“…By comparing to non-transformed cell lines, CPI-613 displays tumor selectivity. Additionally, treatment with CPI-613 leads to cell death also in p53-deficient or KRAS -mutated cell lines [ 194 , 212 , 213 ] as well as in drug-resistant cells [ 214 , 215 , 216 ]. Microarray data showed the reduced expression levels of cyclins as well as CDK2 , p27 and p19 , which point to a preceding cell cycle arrest [ 217 , 218 ].…”

“…Once administered, CPI-613 undergoes biotransformation including phase I oxidation via CYP3A4/5 and CYP2C8 with partially coupled phase II O -glucuronidation and sulfoxide formation as shown in vitro using human S9 mix [ 214 , 215 ]. With respect to cytotoxicity, drug metabolism leads to a decrease or loss of cytotoxicity as compared to the parent compound.…”

“…With respect to cytotoxicity, drug metabolism leads to a decrease or loss of cytotoxicity as compared to the parent compound. Regarding toxicokinetics, the maximum plasma concentration is about 40 µM upon the maximum tolerable dose (MTD) of 2940 mg/m 2 and the half-life of CPI-613 is about 2 h with a triphasic elimination due to enterohepatic circulation [ 202 , 214 , 215 , 232 ].…”

Blockade of glutamine-dependent cell survival augments antitumor efficacy of CPI-613 in head and neck cancer

“…Although the mechanism of action of CPI-613 appears distinct from that of the standard classes of anticancer agents used in the clinic, it clearly demonstrates both in vitro and in vivo anticancer activity [ 8 ]. The anticancer effect of CPI-613 has been evaluated in xenograft models of pancreatic cancer [ 9 ] and applied in patients with metastatic pancreatic cancer, where it has shown strong tumor growth inhibition at its maximum tolerated dose of 500 mg/m 2 [ 10 ].…”