[Palbociclib induces cell cycle arrest and senescence of human renal tubular epithelial cells ].

Objective: To investigate the effect of palbociclib on cell cycle progression and proliferation of human renal tubular epithelial cells.

Methods: Human renal tubular epithelial cell line HK-2 was treated with 1, 5, 10, and 20 μmol/L of palbociclib, and the changes in cell proliferation and viability were examined by cell counting and CCK8 assay. EDU staining was used to assess the proliferation of HK-2 cells following palbiciclib treatment at different concentrations for 5 days. The effect of palbociclib on cell cycle distribution of HK-2 cells was evaluated using flow cytometry. SA-β-Gal staining and C12FDG senescence staining were used to detect senescence phenotypes of HK-2 cells after palbociclib treatment at different concentrations for 5 days. The relative mRNA expression levels of P16, P21, and P53 and the genes associated with senescence-related secretion phenotypes were detected by RT-PCR, and the protein expressions of P16, P21 and P53 were detected by Western blotting.

Results: Palbociclib inhibited HK-2 cell proliferation and induced cell cycle arrest in G1 phase. Compared with the control cells, HK-2 cells treated with high-dose (10 μmol/L) palbociclib exhibited significantly suppressed cell proliferation activity, and the inhibitory effect was the most obvious on day 5 ( < 0.01). Palbociclib treatment significantly reduced the number of cells in S phase ( < 0.01) and induced senescence of HK-2 cells. The results of SA-β-Gal and C12FDG senescence staining showed a significantly enhanced activity of intracellular senescence-related galactosidase in palbociclib-treated HK-2 cells, suggesting significant senescence of the cells ( < 0.01). RT-PCR and Western blotting showed that palbociclib treatment significantly increased the mRNA and protein expression levels of P16, P21, and P53 in HK-2 cells ( < 0.01); the mRNA expression levels of senescence-related secretory factors also increased significantly in HK-2 cells after palbociclib treatment ( < 0.01).

Conclusions: Palbociclib induces HK-2 cell senescence by causing cell growth arrest and delaying cell cycle progression.