MicroRNA-21 And PTEN By Regulating PDCD4 For DLBCL Proliferation, Invasion, And Apoptosis

AIM:MicroRNA-21(miR-21) is considered to play key roles in many cellular processes, affecting tumorigenesis by inhibiting target gene expression. However, its role in diffuse large B-cell lymphoma (DLBCL) is still unclear, and there are no indepth studies on relationship between miR-21and cellular phenotype. In this study, we investigated the expression and role of miR-21in the regulation of cell biological behavior in DLBCL.Methods:1) the expressions of miR-21were evaluated in three DLBCL cell lines by real-time quantitative reverse-transcription polymerase chain reaction (QRT-PCR);2) To determine whether PDCD4and PTEN is the target gene of miR-21, we performed luciferase reporter assay;3) The expressions of miR-21were evaluated in OCI-LY3and OCI-LY10cell by QRT-PCR after transfection.4) The recombinant plasmid OCI-LY3/anti-miR-21、OCI-LY3/miR-control、 OCI-LY10/anti-miR-21. OCI-LY10/miR-control were transfected into OCI-LY3and OCI-LY10cells, and the change of the expression of PDCD4and PTEN mRNA and protein in transfected cells was identified by RT-PCR and Wersternblot;5) The change of proliferation level of the OCI-LY3and OCI-LY10cells after transfection was detected by MTT assay;6) The effect of anti-miR-21on invasion in OCI-LY3and OCI-LY10cells in vitro was detected by transwell chamber;7) The effect of anti-miR-21on apoptosis in OCI-LY3and OCI-LY10cells in vitro was detected by transwell chamber;Results:1) QRT-PCR analysis showed that OCI-LY3and OCI-LY10cells expressed higher levels of miR-21compared with DB cells;2) PDCD4and PTEN were directly targeted by miR-21;3) Upon transfection with anti-miR-21, endogenous protein levels were all significantly increased relative to the effect of the miR-control. However, we did not find any significant inhibition of PDCD4and PTEN at the mRNA level, as measured by QRT-PCR; 4) Compared with the OCI-LY3/miR-control and OCI-LY10/miR-control, the proliferation of the OCI-LY3/anti-miR-21and OCI-LY10/anti-miR-21were inhibited down to87%(P<0.01),85%(P<0.01),77%(P<0.01) and71%(P<0.01),73%(P<0.01),67%(P<0.01) of the pre-transfected levels at the2,3, and4days, respectively;5) Knockdown of miR-21suppressed the OCI-LY3cells invasion by up to71%by60%in the OCI-LY10cells, compared with the miR-control at48h after transfection.*P<0.05;6) A increase in early apoptosis was detected in both the OCI-LY3/anti-miR-21and OCI-LY10/anti-miR-21cells.Conclusion:We demonstrated that inhibition of miR-21induced suppression of proliferation and invasion, as well as increased apoptosis in DLBCL. Moreover, knockdown of miR-21increased the expressions of PDCD4and PTEN at the protein level but not at the mRNA level. In conclusion, miR-21can regulate proliferation, invasion, and apoptosis, so it has a potential therapeutic application in DLBCL.