The RhoA dependent anti-metastatic function of RKIP in breast cancer

Cordyceps sinensis relieves non-small cell lung cancer by inhibiting the MAPK pathway

OBJECTIVE

To determine the pharmacodynamic mechanism underlying Cordyceps sinensis relief in a murine model of non-small cell lung cancer (NSCLC).

METHODS

We created a murine model of NSCLC and studied the potential molecular mechanism by which C. sinensis relieved NSCLC using a combination of transcriptomics, proteomics, and experimental validation.

RESULTS

C. sinensis markedly suppressed the fluorescence values in mice with NSCLC, improved the pathologic morphology of lung tissue, ameliorated inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-10, and the oxidative stress indicators superoxide dismutase, malondialdehyde, and glutathione peroxidase). Transcriptomics results showed that the therapeutic effect of C. sinensis was primarily involved in the differentiation and activation of T cells. Based on the proteomic results, C. sinensis likely exerted a protective effect by recruiting immune cells and suppressing tumor cell proliferation via the MAPK pathway. Finally, the experimental validation results indicated that C. sinensis significantly decreased the VEGF and Ki67 expression, downregulated RhoA, Raf-1, and c-fos expression, which are related to cell migration and invasion, increased the serum concentration of hematopoietic factors (EPO and GM-CSF), and improved the percentage of immune cells (natural killer cells, dendritic cells, and CD4+ and CD8+ lymphocytes), which enhanced immune function.

CONCLUSIONS

Based on our preclinical study, C. sinensis was shown to exert a protective effect on NSCLC, primarily by inhibiting the MAPK pathway.

Metastasis suppressor genes and their role in the tumor microenvironment

The metastatic cascade is a complex process with multiple factors contributing to the seeding and growth of cancer cells at metastatic sites. Within this complex process, several genes have been identified as metastasis suppressors, playing a role in the inhibition of metastasis. Interestingly, some of these genes have been shown to also play a role in regulating the tumor microenvironment. In this review, we comment on the recent developments in the biology of metastasis suppressor genes and their crosstalk with the microenvironment.

Dahuang—Taoren, a botanical drug combination, ameliorates adenomyosis via inhibiting Rho GTPases

Introduction: Dahuang-Taoren (DT) is a classic combination of botanical drugs applied to treat pain-related diseases in ancient China. Today, DT is frequently applied for dysmenorrhea of adenomyosis (AM) in the clinic. Growing evidence indicates Rho GTPases may play an essential role in AM progression. However, the potential mechanism of DT on Rho GTPases in AM remains unclear.

Methods: The expressions of Rho GTPases in the patients with AM were evaluated. Further, pituitary transplantation-induced AM mice and the primary AM endometrial stromal cells (AMESCs) were subjected to DT intervention.

Results: The results revealed that the expressions of Rho GTPases were significantly upregulated in both AM patients and AM mice. The DT could reduce pathological infiltration, relieve hyperalgesia, and alleviate cytoskeleton remodeling in AM mice. Besides, the migration and invasion of AMESCs were markedly inhibited after exposure to DT.

Discussion: These effects may be linked to the decreased Rho GTPases expression. The results may offer a novel explanation of DT against AM.

Changes in Expression of Tumor Suppressor Gene RKIP Impact How Cancers Interact with Their Complex Environment

Tumor microenvironment (TME) is the immediate environment where cancer cells reside in a tumor. It is composed of multiple cell types and extracellular matrix. Microenvironments can be restrictive or conducive to the progression of cancer cells. Initially, microenvironments are suppressive in nature. Stepwise accumulation of mutations in oncogenes and tumor suppressor genes enables cancer cells to acquire the ability to reshape the microenvironment to advance their growth and metastasis. Among the many genetic events, the loss-of-function mutations in tumor suppressor genes play a pivotal role. In this review, we will discuss the changes in TME and the ramifications on metastasis upon altered expression of tumor metastasis suppressor gene RKIP in breast cancer cells.

The Role of RKIP in the Regulation of EMT in the Tumor Microenvironment

Simple Summary

Raf kinase inhibitor protein (RKIP) expression in cancer cells is significantly reduced and promoting cancer cells growth and invasiveness. Overexpresssion of RKIP has been reported to mediate pleiotropic anti-cancer activities including the inhibition of survival signaling pathways, sensitization to cell death by cytotoxic drugs, inhibition of invasion, EMT and metastasis. The molecular mechanism by which RKIP inhibits EMT is not clear. In this review, we have examined how RKIP inhibits the selected EMT gene products (Snail, vimentin, N-cadherin, laminin alpha) and found that it involves signaling cross-talks between RKIP and each of the EMT gene products. These findings were validated by bioinformatic analyses demonstrating in various human cancers a negative correlation between the expression of RKIP and the expression of the EMT gene products. These findings suggest that targeting RKIP induction in cancer cells will result in multiple hits by inhibiting tumor growth, metastasis and reversal of chemo-immuno resistance.

Abstract

The Raf Kinase Inhibitor Protein (RKIP) is a unique gene product that directly inhibits the Raf/Mek/Erk and NF-kB pathways in cancer cells and resulting in the inhibition of cell proliferation, viability, EMT, and metastasis. Additionally, RKIP is involved in the regulation of cancer cell resistance to both chemotherapy and immunotherapy. The low expression of RKIP expression in many cancer types is responsible, in part, for the pathogenesis of cancer and its multiple properties. The inhibition of EMT and metastasis by RKIP led to its classification as a tumor suppressor. However, the mechanism by which RKIP mediates its inhibitory effects on EMT and metastases was not clear. We have proposed that one mechanism involves the negative regulation by RKIP of the expression of various gene products that mediate the mesenchymal phenotype as well as the positive regulation of gene products that mediate the epithelial phenotype via signaling cross talks between RKIP and each gene product. We examined several EMT mesenchymal gene products such as Snail, vimentin, N-cadherin, laminin and EPCAM and epithelial gene products such as E-cadherin and laminin. We have found that indeed these negative and positive correlations were detected in the signaling cross-talks. In addition, we have also examined bioinformatic data sets on different human cancers and the findings corroborated, in large part, the findings observed in the signaling cross-talks with few exceptions in some cancer types. The overall findings support the underlying mechanism by which the tumor suppressor RKIP regulates the expression of gene products involved in EMT and metastasis. Hence, the development of agent that can selectively induce RKIP expression in cancers with low expressions should result in the activation of the pleiotropic anti-cancer activities of RKIP and resulting in multiple effects including inhibition of tumor cell proliferation, EMT, metastasis and sensitization of resistant tumor cells to respond to both chemotherapeutics and immunotherapeutics.