A novel regulatory role of microRNA‑5590‑3p in hepatocellular carcinoma via the HOXB2/MYC axis

The present study aimed to investigate the effects of microRNA (miR)‑5590‑3p on the biological functions of hepatocellular carcinoma (HCC) cells through the homeobox B2 (HOXB2)/MYC axis. The expression levels of miR‑5590‑3p, HOXB2 and MYC were measured in HCC tissues and cell lines, and the relationships between miR‑5590‑3p, HOXB2, and the clinicopathological characteristics and prognosis of patients with HCC were analyzed. The Cell Counting Kit‑8 assay assessed cell proliferation, flow cytometry measured apoptosis rate, and the Transwell and wound healing assays evaluated the invasive and migratory abilities of cells. The targeting interactions between miR‑5590‑3p and HOXB2, and between HOXB2 and MYC were assessed. In addition, a subcutaneous HCC xenograft model was established to assess the effects of miR‑5590‑3p on tumor growth. The results revealed that miR‑5590‑3p expression was downregulated in HCC tissues and cells, whereas HOXB2 and MYC expression were upregulated. Notably, low miR‑5590‑3p expression and high HOXB2 expression were both associated with a poor prognosis in patients with HCC. miR‑5590‑3p directly targeted and suppressed HOXB2, whereas HOXB2 promoted MYC transcription. Furthermore, downregulation of miR‑5590‑3p enhanced the invasion, migration and proliferation of Huh7 cells, and reduced their apoptotic rate. By contrast, miR‑5590‑3p overexpression or HOXB2 silencing decreased invasion, migration and proliferation, while increasing apoptosis. Moreover, HOXB2 overexpression reversed the inhibitory effect of miR‑5590‑3p upregulation on HCC cell proliferation. HOXB2 appeared to promote Huh7 cell proliferation and motility through MYC transcriptional activation, whereas miR‑5590‑3p overexpression suppressed tumor growth in vivo. In conclusion, miR‑5590‑3p may inhibit HCC cell proliferation and motility, and induce apoptosis by targeting HOXB2 and suppressing MYC transcription.