HBx-induced MiR-1269b in NF-κB dependent manner upregulates cell division cycle 40 homolog (CDC40) to promote proliferation and migration in hepatoma cells

Abstract

BackgroundOccurrence and progression of hepatocellular carcinoma (HCC) are associated with hepatitis B virus (HBV) infection. miR-1269b is up-regulated in HCC cells and tissues. However, the regulation of miR-1269b expression by HBV and the mechanism underlying the oncogenic activity of miR-1269b in HCC are unclear.MethodsReverse transcription quantitative PCR (RT-qPCR) was used to measure the expression of miR-1269b and target genes in HCC tissues and cell lines. Western blot analysis was used to assess the expression of miR-1269b target genes and related proteins. Using luciferase reporter assays and EMSA, we identified the factors regulating the transcriptional level of miR-1269b. Colony formation, flow cytometry and cell migration assays were performed to evaluate the phenotypic changes caused by miR-1269b and its target in HCC cells.ResultsWe demonstrated that the expression levels of pre-miR-1269b and miR-1269b in HBV-positive HepG2.2.15 cells were dramatically increased compared with HBV-negative HepG2 cells. HBx was shown to facilitate translocation of NF-κB from the cytoplasm to the nucleus, and NF-κB binds to the promoter of miR-1269b to enhance its transcription. miR-1269b targets and up-regulates CDC40, a cell division cycle 40 homolog. CDC40 increases cell cycle progression, cell proliferation and migration. Rescue experiment indicated that CDC40 promotes malignancy induced by miR-1269b in HCC cells.ConclusionWe found that HBx activates NF-κB to promote the expression of miR1269b, which augments CDC40 expression, contributing to malignancy in HCC. Our findings provide insights into the mechanisms underlying HBV-induced hepatocarcinogenesis.

<p>miR-1269b Drives Cisplatin Resistance of Human Non-Small Cell Lung Cancer via Modulating the PTEN/PI3K/AKT Signaling Pathway</p>

“…29 NF-κB activated the transcription of miR-1269b and then resulted in promoting HCC cell cycle, proliferation and migration. 12 CDC40 was proved to be a target of miR-1269b, promoting malignancy of HCC. 12 Another study showed that TGF-β activated miR-1269 via Sox4 and positively feedback the TGF-β signaling by targeting Smad7 and HOXD10.…”

“…12 CDC40 was proved to be a target of miR-1269b, promoting malignancy of HCC. 12 Another study showed that TGF-β activated miR-1269 via Sox4 and positively feedback the TGF-β signaling by targeting Smad7 and HOXD10. 5 In lung cancer, miR-1269 might promote cell survival and proliferation by targeting TP53 and caspase-9.…”

“…Whether there is a positive feedback mechanism between enhanced PI3K/AKT-NFκB or the NSCLC patients also have enhanced TGF-β signaling remains unknown. 5,12 Second, single miRNA can target multiple genes and single gene can be regulated by multiple miRNAs. 14 Though in this study we demonstrated clearly that miR-1269b regulated PTEN in NSCLC, whether other miRNAs such as miR-26a and miR-21 are also involved in PTEN regulation is not fully addressed.…”

Deregulation of the Notch pathway as a common road in viral carcinogenesis

“…The HBx protein has been associated with hepatocellular carcinogenesis because it sustains HBV replication, 71 interacts and inhibits p53 tumor suppressor, increases telomerase reverse transcriptase (TERT) expression, 72 and promotes invasiveness and metastasis in hepatitis B virus-related HCC. 73,74 HBx does not directly bind to DNA, but regulates transcription factors such as NF-κB), 75 the activator protein 1 (AP-1), 76 cAMP response element-binding protein (CREB), 46 and the coactivator CPB/p300, through which it could upregulate NOTCH target genes, but this still requires further validation ( Figure 3A).…”

“…HBx does not directly bind to DNA, but regulates transcription factors such as NF‐κB), the activator protein 1 (AP‐1), cAMP response element‐binding protein (CREB), and the coactivator CPB/p300, through which it could upregulate NOTCH target genes, but this still requires further validation (Figure A).…”