6-thio-dg is a nucleoside analogue [1], is a telomerase-mediated telomere disrupting compound [2]. it is an anti-cancer inhibitor [1]. cancer cells were very sensitive to 6-thio-dg with observed ic50 values ranging from 0.7-2.9 μm, depending on cell types [3].telomeres are found at the end of eukaryotic linear chromosomes. they are essential for genomic stability and chromosome maintenance [3].in hct116 human colon cancer cell line, treatment with 6-thio-dg made progressive telomere shortening independent of telomerase activity inhibition and induced telomere dysfunction. grn163l is a telomerase inhibitor. in hct116 cells, treatment with grn163l and 6-thio-dg together increased telomere shortening. within 1 week, 6-thio-dg killed most of hct116 cells and altered cellular morphology. normal bj fibroblast cells are telomerase silent. after 1 week, treatment with 6-thio-dg showed no effect on cell morphology. after long-term treatment with 6-thio-dg, no effect on telomere shortening was found [1].in murine mode with xenograft derived from a549 lung cancer cell line, as compared to controls, intraperitoneal injection with 2 mg/kg of 6-thio-dg every other day completely prevented progressive tumor growth. ki67 is a biomarker correlating with proliferation levels. compared to controls, 6-thio-dg decreased ki67 staining. treatment with 6-thio-dg through local injection resulted in even more dramatic decrease in the tumor growth rate compared to untreated controls [3].
[1]. mender i, gryaznov s, dikmen zg, et al. abstract lb-125: a novel telomerase inhibitor. cancer research, 2013, 73(8 supplement): lb-125-lb-125.
[2]. mender i, gryaznov s, shay jw. a novel telomerase substrate precursor rapidly induces telomere dysfunction in telomerase positive cancer cells but not telomerase silent normal cells. oncoscience, 2015, 2(8): 693.
[3]. mender i, gryaznov s, dikmen zg, et al. induction of telomere dysfunction mediated by the telomerase substrate precursor 6-thio-2-deoxyguanosine. cancer discovery, 2015, 5(1): 82-95.
