Background: Obesity was a recognized risk factor for the development and progression of hepatocellular carcinoma (HCC). However, the effects and mechanisms by which obesity promotes HCC metastasis remain poorly understood.
Materials and methods: We cultured adipocyte induced by preadipocyte 3T3-L1 in vitro and established HCC metastasis model in obesity mouse in vivo to mimic the tumor microenvironment in obese status. The mechanisms underlying obesity-associated miR-27a upregulation promoting HCC metastasis were investigated.
Results: In this study, we showed that miR-27a was upregulated in adipocytes, obese mouse model and clinical samples, and the increased miR-27a level promoted migration and invasion in HCC cells, increased the number of metastasis nodes in obese mouse model, and was associated with poor clinical outcomes. Overexpressed secreted frizzled-related protein 1 in HCC cells and tissues significantly alleviated the upregulation of β-catenin and matrix metalloproteinase-7 induced by high level of miR-27a. Meanwhile, the E-cadherin expression decreased and Vimentin expression increased, linking with high level of β-catenin in high-fat group.
Conclusion: Taken together, our results have elucidated the critical role of extracellular miR-27a as a pro-metastatic factor in HCC and revealed that obesity-associated miR-27a upregulation promoted HCC metastasis through activated Wnt/β-catenin signaling by suppressing secreted frizzled-related protein 1. Our findings shed light on the novel mechanism underlying HCC metastasis and provided miR-27a as a promising target for obese liver cancer therapy.
Keywords: obesity, miR-27a, SFRP1, β-catenin, hepatocellular carcinoma