RESUMO
Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of non-Hodgkin lymphoma and is a very aggressive malignancy with tumor growing rapidly in organs like lymph nodes. The pathogenesis of DLBCL is not clear and the prognosis of DLBCL requires improvement. Here, we investigated the mechanisms of DLBCL, with the focus on lncRNA PVT1/miR-34b-5p/Foxp1 axis. Human DLBCL tissues from diagnosed DLBCL patients and four human DLBCL cell lines, one normal human B lymphoblastoid cell line were used. qRT-PCR and western blotting were employed to measure expression levels of lncRNA PVT1, Foxp1, miR-34b-5p, ß-catenin, and proliferation-related proteins. MTT assay and colony formation assay were performed to determine cell proliferation. Flow cytometry was used to examine cell apoptosis. ChIP and Dual-luciferase assay were utilized to validate interactions of Foxp1/promoters, PVT1/miR-34b-5p and miR-34b-5p/Foxp1. Mouse tumor xenograft model was used to determine the effect of sh-PVT1 on tumor growth in vivo. In this study, we found PVT1 and Foxp1 were elevated in DLBCL tissues and cells while miR-34b-5p was decreased. Knockdown of PVT1, overexpression of miR-34b-5p, or Foxp1 knockdown repressed DLBCL cell proliferation but enhanced cell apoptosis. PVT1 directly bound miR-34b-5p to disinhibit Foxp1/ß-catenin signaling. Foxp1 regulated CDK4, CyclinD1, and p53 expression via binding with their promoters. Knockdown of Foxp1 partially reversed the effects of miR-34b-5p inhibitor on DLBCL cell proliferation and apoptosis. Inhibition of PVT1 through shRNA suppressed DLBCL tumor growth in vivo. All in all, lncRNA PVT1 promotes DLBCL progression via acting as a miR-34b-5p sponge to disinhibit Foxp1/ß-catenin signaling.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Linfoma Difuso de Grandes Células B/metabolismo , MicroRNAs/metabolismo , Proteínas de Neoplasias/metabolismo , RNA Longo não Codificante/metabolismo , RNA Neoplásico/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais , Linhagem Celular Tumoral , Fatores de Transcrição Forkhead/genética , Humanos , Linfoma Difuso de Grandes Células B/genética , MicroRNAs/genética , Proteínas de Neoplasias/genética , RNA Longo não Codificante/genética , RNA Neoplásico/genética , Proteínas Repressoras/genéticaRESUMO
OBJECTIVE: To explore the effect of nuclear factor kappa-B (NF-κB) inhibitor pyrrolidine dithiocarbamate (PDTC) on the proliferation and apoptosis of acute leukemia cell HL-60. METHODS: HL-60 cells were cultured with PDTC of 0, 25, 50, 100 µmol/L for 24, 48, 72 h. The inhibition rate of cell proliferation was detected by CCK-8 assay. Cell apoptosis was detected by Hoechst staining. Cell cycle was detected by flow cytometry. The expression of B-cell lymphoma-2 (BCL-2), BCL-2 associated X protein (BAX), cyclinD1, activated cysteinyl aspartate specific proteinase (cleaved caspase 3), cleaved caspase 8 and activation of NF-κB signal pathway related protein was detected by Western blot. RESULTS: After the HL-60 cells were cultured with PDTC of 25, 50, 100 µmol/L for 24, 48, 72 h, the inhibition rate of cell proliferation increased with the enhancement of PDTC concentration at the same time point (r=0.924, P<0.01). At the same PDTC concentration, the inhibition rate of cell proliferation increased with prolonging of time (r=0.952, P<0.01). After HL-60 cell was cultured with PDTC of 25, 50, 100 µmol/L for 48 h, compared with control group, PDTC of 25, 50, 100 µmol/L increased the cell apoptotic rate, arrested cell cycle at G1 phase (P<0.01), the expression of BCL-2, cyclinD1 and p-NF-κB p65 was down-regulated(P<0.05), the expression of BAX, cleaved caspase 3, cleaved caspase 8 was up-regulated(P<0.01). PDTC of 50, 100 µmol/L down-regulated the expression of p-inhibitor of NF-κB (p-IκBα)(P<0.01). CONCLUSION: PDTC can inhibit acute leukemia HL-60 cell proliferation and induce cell apoptosis.