Minjee Kim1,2,#, Hyeyoung Kim1,3,#, Bu-Gyeong Kang4,#, Jooyoung Lee2,5,#, Taegun Kim6,#, Hwanho Lee1,2, Jane Jung1,3, Myung Joon Oh1,2, Seungyoon Seo7, Myung-Jeom Ryu2, Yeojin Sung1,2, Yunji Lee1,2, Jeonghun Yeom7, Gyoonhee Han6, Sun-Shin Cha4, Hosung Jung1,3, Hyun Seok Kim1,2,5
1 Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
2 Department of Biomedical Sciences, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
3 Department of Anatomy, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
4 Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 03760, Republic of Korea.
5 Checkmate Therapeutics Inc., Seoul, 07207, Republic of Korea.
6 Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea.
7 Prometabio Research Institute, Prometabio Co., Ltd. Hanam-si, Gyeonggi-do 12939, Republic of Korea.
# Equal contribution.
Corresponding authors: Hyun Seok Kim (lead contact), Hosung Jung, Sun-Shin Cha, Gyoonhee Han
Background: Exploiting synthetic lethality (SL) relationships between protein pairs has emerged as an important avenue for the development of anti-cancer drugs. Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme of the NAD+ salvage pathway, having an SL relationship with nicotinic acid phosphoribosyltransferase (NAPRT), the key enzyme in the NAD+ Preiss-Handler pathway. NAMPT inhibitor holds clinical potential not only as a promising cancer treatment but also as a means of protection against chemotherapy-induced-peripheral-neuropathy (CIPN). However, as NAD+ is essential for normal cells, the clinical use of NAMPT inhibitors is challenging. This study aimed to identify a novel NAMPT inhibitor with enhanced selective cytotoxicity against NAPRT-deficient cancer cells as well as prominent efficacy in alleviating CIPN.
Methods: We began by conducting drug derivatives screening in a panel of lung cancer cell lines to select an agent with the broadest therapeutic window between the NAPRT-negative and-positive cancer cell lines. Both in vitro and In vivo comparative analyses were conducted between A4276 and other NAMPT inhibitors to evaluate the NAPRT-negative cancer cell selectivity and the underlying distinct NAMPT inhibition mechanism of A4276. Patient-derived tumor transcriptomic data and protein levels in various cancer cell lines were analyzed to confirm the correlation between NAPRT depletion and epithelial-to-mesenchymal transition (EMT)-like features in various cancer types. Finally, the efficacy of A4276 for axonal protection and CIPN remedy was examined in vitro and in vivo.
Results: The biomarker-driven phenotypic screening led to a discovery of A4276 with prominent selectivity against NAPRT-negative cancer cells compared with NAPRT-positive cancer cells and normal cells. The cytotoxic effect of A4276 on NAPRT-negative cells is achieved through its direct binding to NAMPT, inhibiting its enzymatic function at an optimal and balanced level allowing NAPRT-positive cells to survive through NAPRT-dependent NAD+ synthesis. NAPRT deficiency serves as a biomarker for the response to A4276 as well as an indicator of EMT-subtype cancer in various tumor types. Notably, A4276 protects axons from Wallerian degeneration more effectively than other NAMPT inhibitors by decreasing NMN-to-NAD+ ratio.
Conclusion: This study demonstrates that A4276 selectively targets NAPRT-deficient EMT-subtype cancer cells and prevents chemotherapy-induced peripheral neuropathy, highlighting its potential as a promising anti-cancer agent for use in cancer monotherapy or combination therapy with conventional chemotherapeutics.