Zebularine, a cytidine lacking the 4-amino group, is a DNMT inhibitor that inhibits DNA methylation[1]. Zebularine can cause DNA demethylation and enhance cGAS-STING pathway activity, leading to accumulation of DNA fragments in the cytoplasm[2]. Zebularine has been widely used in cell models to inhibit tumor growth and alter cancer cell gene expression[3].
In vitro, Zebularine treatment for 24 hours significantly inhibited the viability of HCCLM3, MHCC97H, and MHCC97L cells with IC50 values of 56.75µM, 59.72µM, and 64.93µM, respectively[4]. Treatment of MDA-MB-231 cells with 200µM Zebularine for 96 hours significantly inhibited cell proliferation, induced S-phase arrest, and resulted in decreased expression of cyclins B and D[5]. Treatment of A549 cells with 100µM Zebularine for 72h induced apoptosis, accompanied by loss of mitochondrial membrane potential, decrease of Bcl-2, increase of Bax and p53, and activation of caspase-3 and caspase-8[6].
In vivo, Zebularine treatment via oral administration at a dose of 100mg/kg every four days for 20 days significantly inhibited tumor growth in the BGC823 cell xenograft mouse model[7]. Daily intraperitoneal injection of Zebularine (225mg/kg) for 7 days reduced the fibrotic lesion area and inflammatory response in the kidney in a mouse model of unilateral ureteral obstruction (UUO)[8].
References:
[1] Champion C, Guianvarc'h D, Sénamaud-Beaufort C, et al. Mechanistic insights on the inhibition of c5 DNA methyltransferases by zebularine[J]. PloS one, 2010, 5(8): e12388.
[2] Lai J, Fu Y, Tian S, et al. Zebularine elevates STING expression and enhances cGAMP cancer immunotherapy in mice[J]. Molecular Therapy, 2021, 29(5): 1758-1771.
[3] Cheng J C, Yoo C B, Weisenberger D J, et al. Preferential response of cancer cells to zebularine[J]. Cancer cell, 2004, 6(2): 151-158.
[4] Sanaei M, Kavoosi F. Effect of zebularine on apoptotic pathways in hepatocellular carcinoma cell lines[J]. International Journal of Preventive Medicine, 2023, 14(1): 63.
[5] Billam M, Sobolewski M D, Davidson N E. Effects of a novel DNA methyltransferase inhibitor zebularine on human breast cancer cells[J]. Breast cancer research and treatment, 2010, 120(3): 581-592.
[6] You B R, Park W H. Zebularine inhibits the growth of A549 lung cancer cells via cell cycle arrest and apoptosis[J]. Molecular Carcinogenesis, 2014, 53(11): 847-857.
[7] Tan W, Zhou W, Yu H, et al. The DNA methyltransferase inhibitor zebularine induces mitochondria-mediated apoptosis in gastric cancer cells in vitro and in vivo[J]. Biochemical and biophysical research communications, 2013, 430(1): 250-255.
[8] Koh E S, Kim S, Son M, et al. The protective effect of zebularine, an inhibitor of DNA methyltransferase, on renal tubulointerstitial inflammation and fibrosis[J]. International Journal of Molecular Sciences, 2022, 23(22): 14045.