Abstract
MicroRNA (miRNA) regulates gene expression via mRNA degradation or preventing mRNA from being translated. MiR-122 not only reduces cell proliferation and cell cycling, but induces cell apoptosis in heptocellular carcinoma (HCC) cell lines. Moreover, miR-151 increases HCC cell migration and invasion by directly targeting RhoGDIA in HCC. Therefore, the overriding objective of this study was to develop Sleeping Beauty-based baculovirus vectors that persistently expressed a miR-151-specific sponge or harbored a cluster comprising pre-miR-122 separately or simultaneously with the system approach to inhibiting Mahlavu cell line proliferation and metastasis in vivo. First of all, we injected four types of baculovirus, named m122 (harboring a cluster comprising pre-miR-122), s151 (expressing a miR-151-specific sponge), Dual (accommodating both cassettes), CdE (harboring the d2EGFP gene under the transcriptional control of cytomegalovirus immediate-early (CMV-IE) promoter) or PBS within Sodium butyrate into the subcutaneous Mahlavu tumor. Tumor volume was then continuously monitored by measuring with calipers. The growth of tumors injected with m122, s151 or Dual was obviously inhibited. Using immunohistochemistry, we provide evidence that m122 and Dual induced HCC apoptosis and cell cycle arrest. Moreover, the ability of cell metastasis was all inhibited by m122, s151 and Dual. On the other hand, the number of lung metastases was significantly lower in group m122, s151, or Dual compared with controls. These data collectively demonstrated the feasibility of baculovirus-mediated miRNA regulation for modulating HCC cell migration and invasion, thus implicating its potential for future HCC treatment.