Abstract 258: Preclinical study of nucleic acid therapeutics targeting the Warburg effect.

Abstract Background Cancer cells rely on glycolysis for energy, known as the Warburg effect, which supports survival by promoting nucleotide synthesis, reducing oxidative stress, and inhibiting cell death. Polypyrimidine tract-binding protein 1 (PTBP1) regulates pyruvate kinase muscle (PKM1/PKM2) splicing, maintaining a PKM2-dominant state. Suppressing PTBP1 shifts cellular metabolism to a PKM1-dominant state, reduces glycolysis, alters ATP production, and increases oxidative stress, ultimately resulting in cell death. We developed optimized chemically modified siR-PTBP1 derivatives to evaluate their therapeutic potential. Methods Anti-proliferative activity in human colorectal DLD-1 cells was tested by chemically modified siR-PTBP1 derivatives. Cell viability was assessed by CVS assay, and PTBP1, PKM1/PKM2, and cleaved PARP protein levels were analyzed by Western blotting and immunostaining after the transfection. ATP production and oxidative stress assay were performed to examine the alternation from glycolysis-dominant to oxidative phosphorylation via TCA cycle. Metabolome analysis was also examined. Results Among 14 derivatives, the derivative siR-2-6 significantly suppressed PTBP1, increased PKM1 expression, and raised the PKM1/PKM2 ratio. Increased cleaved PARP expression indicated apoptosis induction and Warburg effect suppression. Also, siR-2-6 increased ATP production and oxidative stress, resulting in apoptosis. The higher RNase resistance and biological activity under RNase-containing conditions were shown in comparison to those of the SiR-2-1 that is not chemically modified. Conclusion Optimized siR-PTBP1 derivatives increased the PKM1/PKM2 ratio and partially shifted cellular metabolism from glycolysis dependence to oxidative phosphorylation, highlighting their potential as nucleic acid therapeutics. The enhanced RNase resistance of siR-2-6 further supports its promise for in vivo application and clinical translation. Citation Format: Keita Matsumoto, Hirokatsu Hayashi, Seito Fujibayashi, Noriki Mitsui, Takeshi Horaguchi, Yuji Hatanaka, Ryoma Yokoi, Ayana Yokoyama, Chika Mizutani, Masashi Kuno, Masahiro Fukada, Ryuichi Asai, Itaru Yasufuku, Yuta Sato, Jesse Yu Tajima, Yoshihiro Tanaka, Nobuhisa Matsuhashi. Preclinical study of nucleic acid therapeutics targeting the Warburg effect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 258.