Down-regulation of SENP1 Expression Increases Apoptosis of Burkitt Lymphoma Cells

Objective: To investigate the effect of down-regulation of Sentrin/SUMO-specific protease 1 (SENP1)expression on the apoptosis of human Burkitt lymphoma cells (Daudi cells) and potential mechanisms.
Methods:Short hairpin RNA (shRNA) targeting SENP1 was designed and synthesized and then cloned into a lentiviralvector. A lentiviral packaging plasmid was used to transfect Daudi cells (sh-SENP1-Daudi group). Daudi cellswithout transfection (Daudi group) and Daudi cells transfected with blank plasmid (sh-NC-Daudi group) servedas control groups. Flow cytometry was performed to screen GFP positive cells and semiquantitative PCR andWestern blot assays were employed to detect the inference efficiency. The morphology of cells was observedunder a microscope before and after transfection. Fluorescence quantitative PCR and Western blot assays wereconducted to measure the mRNA and protein expression of apoptosis related molecules (caspase-3, 8 and 9). Aftertreatment with COCl2 for 24 h, the mRNA and protein expression of hypoxia inducible factor -1α (HIF-1α) wasdetermined.
Results: Sequencing showed the expression vectors of shRNA targeting SENP1 to be successfullyconstructed. Following screening of GFP positive cells by FCM, semiqualitative PCR showed the interferenceefficiency was 79.2±0.026%. At 48 h after transfection, the Daudi cells became shrunken, had irregular edgesand presented apoptotic bodies. Western blot assay revealed increase in expression of caspase-3, 8 and 9 withprolongation of transfection (P<0.05). Following hypoxia treatment, mRNA expression of HIF-1α remainedunchanged in three groups (P>0.05) but the protein expression of HIF-1α markedly increased (P<0.05). However,in the sh-SENP1-Daudi group, the protein expression of HIF-1α remained unchanged
Conclusion: SENP1-shRNAcan efficiently inhibit SENP1 expression in Daudi cells. SENP1 inhibition may promote cell apoptosis. Thesefindings suggest that SENP1 may serve as an important target in the gene therapy of Burkitts lymphoma.