[miR-455 Inhibits HepG2 Cell Proliferation and Promotes Apoptosis by Targeting RhoC]

Silencing of RhoC induces macrophage M1 polarization to inhibit migration and invasion in colon cancer via regulating the PTEN/FOXO1 pathway

Ras homologue family member C (RhoC) is an oncogene in diverse types of human cancers, whereas its regulatory mechanisms involving macrophage polarization is rarely investigated. This study is designed to explore the regulatory role of RhoC in colon cancer and the underlying molecular mechanisms involving macrophage polarization. We detected RhoC expression by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, and analysed the biological function of RhoC knockdown in CC cells by the MTT, wound healing and transwell assay. Macrophage polarization-associated markers, genes associated with migration, phosphatase and tensin homologue (PTEN) and forkhead box O (FOXO) were determined by qRT-PCR and western blot. The xenograft tumour mouse model was used to assess the role of RhoC in vivo. RhoC is highly expressed in CC cells. The cell viability, invasion and migration abilities of CC cells were reduced by knockdown of RhoC. RhoC knockdown promoted M1 polarization, inhibited M2 polarization and decreased levels of genes associated with migration (matrix metalloproteinase-2 and matrix metalloproteinase-9). Silencing of RhoC inhibited tumour growth and expression of genes associated with migration in the xenografted model. In addition, silencing of RhoC promoted PTEN/FOXO1 expression, and PTEN inhibitor (SF1670) reversed the inhibitory effects of RhoC silencing. We demonstrated that silencing of RhoC reduced CC cells invasion and migration, and tumour growth by suppressing M2 macrophage polarization via regulating the PTEN/FOXO1 pathway.

Role of RhoC in cancer cell migration

Migration is one of the five major behaviors of cells. Although RhoC—a classic member of the Rho gene family—was first identified in 1985, functional RhoC data have only been widely reported in recent years. Cell migration involves highly complex signaling mechanisms, in which RhoC plays an essential role. Cell migration regulated by RhoC—of which the most well-known function is its role in cancer metastasis—has been widely reported in breast, gastric, colon, bladder, prostate, lung, pancreatic, liver, and other cancers. Our review describes the role of RhoC in various types of cell migration. The classic two-dimensional cell migration cycle constitutes cell polarization, adhesion regulation, cell contraction and tail retraction, most of which are modulated by RhoC. In the three-dimensional cell migration model, amoeboid migration is the most classic and well-studied model. Here, RhoC modulates the formation of membrane vesicles by regulating myosin II, thereby affecting the rate and persistence of amoeba-like migration. To the best of our knowledge, this review is the first to describe the role of RhoC in all cell migration processes. We believe that understanding the detail of RhoC-regulated migration processes will help us better comprehend the mechanism of cancer metastasis. This will contribute to the study of anti-metastatic treatment approaches, aiding in the identification of new intervention targets for therapeutic or genetic transformational purposes.