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Updated: Feb 15, 2026

Generation and Isolation of Cell Cycle-arrested Cells with Complex Karyotypes
Published on: April 13, 2018
While reinforcing cell cycle arrest, rapamycin and Torins suppress senescence in UVA-irradiated fibroblasts
Olga V Leontieva1, Mikhail V Blagosklonny1
1Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY, USA.
Abstract:
Sunlight predisposes to skin cancer and melanomas. Ultraviolet A (UVA), a long wave component of sunlight, can reach dermal fibroblasts. Here we studied UVA-induced senescence in human fibroblasts in vitro. It is known that senescence occurs, when cell cycle is arrested, but mTOR is still active, thus converting arrest to senescence (geroconversion). We showed that, while arresting cell cycle, UVA did not inhibit mTOR, enabling geroconversion. In UVA-treated cells, mTOR remained fully active. Rapamycin and Torins 1/ 2 prevented UVA-induced senescent phenotype, although they further re-enforced cell cycle arrest. Given that senescent stromal fibroblasts support tumorigenesis, we envision that mTOR inhibitors may potentially be used to prevent sunlight-caused tumors as well as skin photo-aging.
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