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

by Selleckchem | Nov 04 2023

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.

Comments:

The study you described focuses on investigating the regulatory role of Ras homologue family member C (RhoC) in colon cancer, specifically its involvement in macrophage polarization and the underlying molecular mechanisms. Here is a breakdown of the key findings:

1. RhoC expression: The study detected high expression of RhoC in colon cancer (CC) cells.

2. Biological functions of RhoC knockdown: RhoC knockdown using techniques such as quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis resulted in reduced cell viability, invasion, and migration abilities of CC cells. This suggests that RhoC plays a role in promoting these cancer-associated properties.

3. Macrophage polarization: The study explored the effects of RhoC knockdown on macrophage polarization. Macrophages can be polarized into two distinct phenotypes: M1, which is associated with an anti-tumor response, and M2, which is associated with pro-tumor effects. RhoC knockdown promoted M1 polarization of macrophages while inhibiting M2 polarization. This finding suggests that RhoC may contribute to the pro-tumor environment by influencing macrophage polarization.

4. Genes associated with migration: RhoC knockdown also decreased the expression levels of genes involved in migration, specifically matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). These genes are known to play a role in cancer cell invasion and metastasis.

5. In vivo study: A xenograft tumor mouse model was used to assess the role of RhoC in colon cancer growth. Silencing RhoC in this model inhibited tumor growth and reduced the expression of migration-associated genes, further supporting the role of RhoC in promoting cancer progression.

6. PTEN/FOXO1 pathway: Silencing RhoC led to the upregulation of phosphatase and tensin homologue (PTEN) and forkhead box O1 (FOXO1), two molecules involved in regulating cell survival, proliferation, and migration. Inhibition of PTEN using a specific inhibitor (SF1670) reversed the inhibitory effects of RhoC silencing, indicating that RhoC may regulate CC cell invasion and migration through the PTEN/FOXO1 pathway.

Overall, this study demonstrates that RhoC is highly expressed in colon cancer cells and promotes tumor growth by influencing macrophage polarization, enhancing migration-associated genes, and modulating the PTEN/FOXO1 pathway. Silencing RhoC reduces CC cell invasion, migration, and tumor growth by suppressing M2 macrophage polarization and regulating the PTEN/FOXO1 pathway.