Let-7a and miR-34a Interplay Potent Suppressive Roles in Hepatocellular Carcinoma via Co-Targeting FNDC3B, IGF2 and SOX4

Both let-7a and miR-34a have been repeatedly studied as pivotal suppressors for Hepatocellular carcinoma; however, their combined regulations remain to be fully elucidated. In the present study, we performed a comprehensive in silico analysis for let-7a and miR-34a using a wealth of updated tools: miRWalk, Genetrail and miRnet. In addition, our study is the first to quantify both miRs and their three predicted yet not experimentally validated oncogenic targets: FNDC3B, IGF2 and SOX4. This was assessed in HepG2 cell model following treatment by PEGP-vector expressing the miRs by MTT assay, florescence microscopy, qPCR and immune-florescence. Our bioinformatics analysis revealed a pool of common predicted hepatocarcinogenic targets shared by both let-7a and miR-34a. Importantly, three targets were identified as co-regulated through multiple canonical binding sites for each miR, and these had not been experimentally validated before. Furthermore, functional enrichment of these putative targets demonstrated their significant involvement in major and emerging HCC hallmarks, such as reprogramming of energy metabolism and evading immune destruction. These findings support our concept of simultaneous co-regulation of these oncogenes through the signaling networks and GO terms associated with both miRs. Consistently, our experimental results verified the significant overexpression of both miRs in HepG2 cells, leading to reduced tumor cell proliferation and decreased levels of the three oncogenic transcripts. Interestingly, miR-34a exhibited a superior suppression effect, reaching 38.7%, and SOX4 was identified as the most significantly downregulated target at both transcriptional and translational levels. Our findings provide new insights into the interconnected anti-HCC effects of let-7a and miR-34a and highlight the potential of applying their combined use to achieve the best therapeutic outcomes for this invasive tumor.