Inhibition of Cyclin F Promotes Cellular Senescence through Cyclin-dependent Kinase 1-mediated Cell Cycle Regulation.

OBJECTIVE: Kidney renal clear cell carcinoma (KIRC) is a common renal malignancy that has a poor prognosis. As a member of the F box family, cyclin F (CCNF) plays an important regulatory role in normal tissues and tumors. However, the underlying mechanism by which CCNF promotes KIRC proliferation still remains unclear. METHODS: Bioinformatics methods were used to analyze The Cancer Genome Atlas (TCGA) database to obtain gene expression and clinical prognosis data. The CCK8 assay, EdU assay, and xenograft assay were used to detect cell proliferation. The cell senescence and potential mechanism were assessed by SA-ß-gal staining, Western blotting, as well as ELISA. RESULTS: Our data showed that CCNF was highly expressed in KIRC patients. Meanwhile, downregulation of CCNF inhibited cell proliferation in vivo and in vitro. Further studies showed that the reduction of CCNF promoted cell senescence by decreasing cyclin-dependent kinase 1 (CDK1), increasing the proinflammatory factors interleukin (IL)-6 and IL-8, and then enhancing the expression of p21 and p53. CONCLUSION: We propose that the high expression of CCNF in KIRC may play a key role in tumorigenesis by regulating cell senescence. Therefore, CCNF shows promise as a new biomarker to predict the clinical prognosis of KIRC patients and as an effective therapeutic target.

[Effects of arsenic trioxide on the proliferation of human breast cancer SKBR-3 cell and the expression of Notch1].

OBJECTIVE: To study the effects of arsenic trioxide (As2O3) on the proliferation and the migration force of human breast cancer SKBR-3 cell and the expression of Notch1. METHODS: SKBR-3 cells were cultured with different concentrations of As2O3 for 24 h and with the final concentration of 8 micromol/L for 24, 48, and 72 h. The effects of As2O3 on the cell proliferation of SKBR-3 were detected by MTT assay. The effects of the migration force of SKBR-3 cells were detected by Transwell. The expression of Notch1 mRNA was detected using reverse transcription polymerase chain reaction (RT-PCR). The expression of Notch1 protein was detected using Western blot. RESULTS: As2O3 could significantly inhibit the proliferation of SKBR-3 cells in a concentration- and time-dependent manner (P < 0.05). It also could inhibit the migration force of SKBR-3 cells (P < 0.05). Results of RT-PCR and Western blot showed that Notch1 mRNA and protein levels obviously decreased (P < 0.05). CONCLUSION: As2O3 could inhibit the expression of Notch1 and the cell proliferation and the migration force of SKBR-3 cells, which primarily revealed that As2O3 might affect the biological behavior of human breast cancer cells possibly through Notch1 signaling pathway, thus providing theoretical and experimental bases for treating breast cancer by arsenic.