Abstract 938: Metabolomic analysis on pharmacological responses to oxaliplatin plus 5-FU in colorectal cancer cells

Abstract

Abstract Purpose: Oxaliplatin (L-OHP) in combination with 5-fluorouracil (5-FU)/leucovorin (FOLFOX regimen) is an important treatment of metastatic colorectal cancer. However, metabolic functions to determine pharmacological response to L-OHP in combination with 5-FU are still unclear. The purpose of this study is to elucidate metabolomic responses to L-OHP in combination with 5-FU and key pathways relating to chemosensitivity. Experimental Procedures: Human colorectal carcinoma, HCT116 (high-sensitive) and DLD-1 (low-sensitive) cells, were exposed to L-OHP, 5-FU or L-OHP plus 5-FU. After treatment with the anti-cancer agents, the intracellular metabolites were extracted by liquid-liquid extraction and simultaneously and quantitatively analyzed by capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). The mRNA expression level of spermidine/spermine N1-acetyltransferase (SSAT) was measured by real-time quantitative RT-PCR (Taqman PCR). Results: N1-acetylspermine and N8-acetylspermidine in polyamine metabolism were accumulated to a greater extent after L-OHP exposure in drug-sensitive cancer cells. The mRNA expression level of SSAT-1, a key enzyme in polyamine catabolism, increased after L-OHP exposure in drug-sensitive cancer cells but not drug-resistant cancer cells. In addition to the up-regulation of polyamine metabolism in drug-sensitive cancer cells, the intracellular levels of endogenous nucleotides remarkably increased after L-OHP exposure in drug-sensitive cancer cells. These results imply the changes in nucleotide metabolism due to the disruption of DNA synthesis by L-OHP. The intracellular level of α-alanine also accumulated after L-OHP exposure in drug-sensitive cancer cells. α-alanine is known as a pyrimidine catabolite of uracil. These results show that nucleotide metabolism and polyamine metabolism may be important metabolic pathways relating to L-OHP chemosensitivity. Furthermore, in drug-sensitive cancer cells, polyamine metabolism, glutathione metabolism, and nucleotide metabolism were up-regulated after exposure to L-OHP plus 5-FU. On the other hand, metabolites belonging to each metabolic pathway on the whole increased moderately after exposure to L-OHP plus 5-FU in drug-resistant cancer cells. Conclusions: Polyamine metabolism, glutathione metabolism, and nucleotide metabolism are important metabolic pathways relating to responsiveness to L-OHP plus 5-FU. The present CE-TOFMS metabolome analysis created a new finding on metabolomic response to L-OHP plus 5-FU in colorectal cancer cells with different chemosensitivities. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 938. doi:1538-7445.AM2012-938