Abstract:

Objective To explore the changes and significane of USP20 and HIF-α expression in breast cancer. Methods Following transfection of shRNA-USP20 lentivirus into breast cancer MDA-MB-231 cells， the gene and protein expression levels of USP20 were detected using fluorescence quantitative PCR and Western Blot. Subsequently， the overexpression of USP20 was observed to determine its effect on HIF-α expression. Similarly， siRNA-USP20 was used to knock down USP20 in breast cancer MDA-MB-231 cells， followed by detection of gene and protein expression levels using fluorescence quantitative PCR and Western Blot. The subsequent changes in HIF-α expression were then examined. Rusults The positive expression rates of USP20 and HIF-α in breast cancer tissues were 69.6% and 46.83%， respectively， while they were negatively expressed in the adjacent normal tissues， with statistically significant differences （P < 0.01）. The positive expressions of USP20 and HIF-α were predominantly observed in the cytoplasm of breast cancer tissue， with a smaller amount present in the nucleus. There was a significant positive correlation between USP20 and HIF-α in breast cancer. Following transfection of shRNA-USP20 lentivirus into MDA-MB-231 cells， both the protein and gene expression levels of USP20 significantly increased （P < 0.01）. Over-expression of USP20 did not affect HIF-α mRNA levels but led to a significant increase in HIF-α protein expression （P < 0.01）. Conversely， siRNA-USP20 interference resulted in a significant decrease in both the protein and gene expression levels of USP20 （P < 0.01）， without affecting HIF-α mRNA levels； however， it caused a notable reduction in HIF-α protein expression （P < 0.01）. Conclusion The expression of USP20 exhibited a significant positive correlation with HIF-α in breast cancer. Overexpression of USP20 led to a substantial increase in HIF-α protein expression， while knock-down of the USP20 gene resulted in a significant decrease in HIF-α protein levels. Therefore， it can be inferred that USP20 may exert its influence on the development of breast cancer through modulation of HIF-α expression， thereby providing crucial experimental evidence for clinical treatment， prognosis， and further investigations.

Key words: breast cancer, ubiquitin-specific proteases 20, hypoxia inducible factor-1α, pathological features