The Correlation Between RhoA Expression and Clinicopathological Characteristics in Gastric Cancer Patients After Curative Surgery

RHOA protein expression correlates with clinical features in gastric cancer: a systematic review and meta-analysis

Background

Gastric cancer (GC) is one of the most fatal cancers worldwide and is generally only detected after it has progressed to an advanced stage. Since there is a lack of comprehensive data on RHOA protein expression of patients with GC, this study utilized a systematic review and meta-analysis to address the limitation. The objective of this meta-analysis was to link GC clinical features with RHOA protein high- vs. low-expressing patients with GC.

Methods

The PubMed and Web of Science were used for a systematic literature review of GC related to RHOA. The included studies were obtained from two literature databases from past to Aug 31, 2021, by searching keywords. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The odds ratios (ORs) and 95% confidential intervals (CIs) for clinical features were estimated according to the high and low protein expression levels of RhoA. The mean effect sizes of ORs were obtained using the random-effects and fixed-effects models of meta-analysis. Heterogeneity of the studies was assesed by using statistics: τ², I²; and Q values. The symmetry of funnel plots were inspected for publication bias.

Results

Finally, 10 studies including 1,389 patients with GC (735 RHOA-positive and 654 RHOA-negative) were eligible for our meta-analysis to estimate associations between the protein expression and clinical features (e.g., Union for International Cancer Control [UICC] stage progression, differentiation, Lauren histological classification, and vascular invasion). In our meta-analysis, RHOA positive expression was determined to have a statistically significant association with UICC stage progression (P = 0.02) and poorly differentiated status (P = 0.02). The association between RHOA positivity and Lauren subtypes was not statistically significant (P = 0.07).

Conclusions

This meta-analysis suggested that RhoA protein expression in patients with GC was associated with clinical features: UICC stage progression and poorly differentiated status. Our findings are inconclusive but indicate that high RHOA protein expressing patients with GC could predict advanced UICC stages. A large prospective cohort study is required for validation in future.

RhoA, Claudin 18, and c-MET in Gastric Cancer: Clinicopathological Characteristics and Prognostic Significance in Curative Resected Patients

Background: Recently, markers related to molecular classification were suggested as promising therapeutic targets for treatment and prediction of prognosis in gastric cancer (GC), including c-MET, RhoA, and Claudin-18 (CLDN18). This study aimed to investigate their expression in GC and its correlation with clinicopathological characteristics and survival. Methods: We retrospectively evaluated GC patients who underwent curative gastrectomy. c-MET, RhoA, and CLDN18 were analyzed through immunohistochemistry (IHC), and groups for analysis were determined according to the median values obtained for each marker. Results: Among the 349 GC evaluated, 180 (51.6%), 59 (16.9%), and 61 (17.5%) patients were completely negative for c-MET, RhoA, and CLDN18, respectively. Total gastrectomy, D1 lymphadenectomy, poorly differentiated histology, and greater inflammatory infiltrate were more frequent in the c-MET-negative group. Diffuse type, greater inflammatory infiltrate, and advanced pT and pTNM stage were associated with low-RhoA GC. The venous invasion was more frequent in the low-CLDN18 group. Furthermore, c-MET was positively correlated with RhoA and negatively with CLDN18. HER2 expression was associated with c-MET-positive and high-CLDN18 GC; and loss of E-cadherin expression in c-MET-negative and low-RhoA GC. c-MET-negative and Low-RhoA were significantly associated with worse disease-free survival. Conclusions: c-MET, RhoA, and CLD18 expression occurred frequently in GC. RhoA GC had distinct clinicopathological characteristics related to prognosis. c-MET and RhoA were associated with survival but were not independent predictors of prognosis.

Enhancing gene regulatory networks inference through hub-based data integration

One of the main research topics in computational biology is Gene Regulatory Network (GRN) reconstruction that refers to inferring the relationships between genes involved in regulating cell conditions in response to internal or external stimuli. To this end, most computational methods use only transcriptional gene expression data to reconstruct gene regulatory networks, but recent studies suggest that gene expression data must be integrated with other types of data to obtain more accurate models predicting real relationships between genes. In this study, a diffusion-based method is enhanced to integrate biological data of network types besides structural prior knowledge. The Random Walk with Restart algorithm (RWR) with an emphasis on hub nodes is executed separately on each network, and then jointly optimizes low-dimensional feature vectors for network nodes by diffusion component analysis. Next, these feature vectors are used to infer gene regulatory networks. Fourteen centrality measures are studied for the detection of hub nodes to be used in the RWR algorithm, and the best centrality measure having the greatest effect on the improvement of gene network inference is selected. A case study for the Saccharomyces cerevisiae and E. coli networks shows that using the proposed features in comparison with gene expression data alone results in 0.02-0.08 units improvement in Area Under Receiver Characteristic Operator (AUROC) criteria across different gene regulatory network inference methods. Furthermore, the proposed method was applied to the esophageal cancer data to infer its gene regulatory network. The proposed framework substantially improves accuracy and scalability of GRN inference. The fused features and the best centrality measure detected can be used to provide functional insights about genes or proteins in various biological applications. Moreover, it can be served as a general framework for network data and structural data integration and analysis problems in various scientific disciplines including biology.

Identification of "regulation of RhoA activity panel" as a prognostic and predictive biomarker for gastric cancer

RhoA is a member of the RHO family GTPases and is associated with essential functions in gastric cancer. In this study, we identified a gastric cancer biomarker, termed the “regulation of RhoA activity panel” (RRAP). Patients with gastric cancer from The Cancer Genome Atlas database were divided into training (N=160) and validation (N=155) cohorts. A cohort of 109 Chinese gastric cancer patients was utilized as an independent validation. Patients with mutated RRAP showed significantly better overall survival than patients with wild type RRAP. We also analyzed the association between RRAP and the migration capacity, immune-related signatures, and the tumor microenvironment. RRAP-mutant tumors had a significantly lower degree of lymph node metastasis and lower activities of migration-related pathways. These tumors also showed significantly increased immune cell infiltration and cytotoxic activity. Furthermore, two independent patient cohorts who received immune checkpoint blockade therapy were assessed for RRAP mutant status. As expected, for both immunotherapy cohorts, higher response rates to immune checkpoint blockade therapy were observed in patients with RRAP-mutant tumors than in patients with wild type RRAP tumors. Overall, this study indicates that the RRAP gene set is a potential biomarker for gastric cancer prognosis and therapeutic selection.

Impact of RhoA overexpression on clinical outcomes in cervical squamous cell carcinoma treated with concurrent chemoradiotherapy

The Rho-associated coiled-coil-containing protein kinase (ROCK) pathway is known to influence metastasis in several cancers; however, the impact of the pathway on clinical outcomes in patients undergoing radiotherapy remains unknown. In the present study, the expression of RhoA, RhoC, ROCK-1, ROCK-2 and p53 was immunohistochemically evaluated using biopsy specimens obtained from 49 patients with stage II-III cervical squamous cell carcinoma treated with concurrent chemoradiotherapy (CCRT). The relationship between the expression of these proteins and patient outcomes was investigated. RhoA overexpression was associated with significantly impaired disease-free survival and distant metastasis-free survival (P = 0.045 and P = 0.041, respectively) in stage III cancer patients. No differences in survival were observed based on the expression of the other proteins among stage III cancer patients. In stage II cancer patients, no differences in survival were noted based on the expression of any of the proteins. The expression of RhoA was able to successfully differentiate cervical cancer patients with distant metastasis after CCRT. This information may help stratify patients according to the risk of metastasis, thereby leading to the potential to provide individualized treatment.

A high expression ratio of RhoA/RhoB is associated with the migratory and invasive properties of basal-like Breast Tumors

Basal-like breast cancer is among the most aggressive cancers and there is still no effective targeted treatment. In order to identify new therapeutic targets, we performed mRNA-Seq on eight breast cancer cell lines. Among the genes overexpressed in basal-like tumors, we focused on the RhoA and RhoB genes, which encode small GTPases known to play a role in the actin cytoskeleton, allowing cells to migrate. qRT-PCR and Western blotting were used for expression studies. Migratory and invasive properties were analysed by wound healing and Boyden chambers assays. Stress fibers formation was evaluated by fluorescent actin labeling. Rho siRNA, small inhibitor Rhosin treatment and BRCA1 transfection were performed to study the role of Rho and BRCA1 proteins. We showed that strong expression of RhoA and low expression of RhoB was associated with the basal-like subtype of breast cancer. Decreasing RhoA expression reduced the migratory and invasive capacities of basal-like cell lines, while decreasing RhoB expression increased these capacities. Rhosin, an inhibitor of RhoA, could also reduce the migration of basal-like cell lines. Rho proteins are involved in the formation of stress fibers, a conformation of the actin cytoskeleton found in migrating cells: inhibition of RhoA expression decreased the formation of these fibers. BRCA1, a gene frequently inactivated in basal-like tumors, appears to play a role in the differential expression of RhoA and RhoB in these tumors, as the restoration of BRCA1 expression in a BRCA1-mutated basal-like cell line decreased expression of RhoA and increased expression of RhoB, resulting in reduced migratory capacity. These results suggest Rho proteins as potential therapeutic targets for basal-like and BRCA1-mutated breast cancer, as migration and acquisition of mesenchymal properties are key functional pathways in these tumors with high metastatic potential.

RHOA in Gastric Cancer: Functional Roles and Therapeutic Potential

The well-known signal mediator and small GTPase family member, RHOA, has now been associated with the progression of specific malignancies. In this review, we appraise the biomedical literature regarding the role of this enzyme in gastric cancer (GC) signaling, suggesting potential clinical significance. To that end, we examined RHOA activity, with regard to second-generation hallmarks of cancer, finding particular association with the hallmark "activation of invasion and metastasis." Moreover, an abundance of studies show RHOA association with Lauren classification diffuse subtype, in addition to poorly differentiated GC. With regard to therapeutic value, we found RHOA signaling to influence the activity of specific widely used chemotherapeutics, and its possible antagonism by various dietary constituents. We also review currently available targeted therapies for GC. The latter, however, showed a paucity of such agents, underscoring the urgent need for further investigation into treatments for this highly lethal malignancy.

The Clinical Implication of PTEN and FAK Expression in Gastric Cancer Patients

Objective:

The tumor suppressor gene phosphatase and tensin homolog (PTEN) was reported to inhibit the growth and invasion of gastric cancer (GC) via the downregulation of focal adhesion kinase (FAK). To date, the clinical implication of PTEN and FAK expression in GC has not been well addressed.

Methods:

A total of 200 GC patients receiving curative surgery were enrolled. The clinicopathologic features according to the expression of PTEN and FAK protein using immunohistochemical staining were compared among patients.

Results:

Patients with high PTEN expression were more likely to have smaller tumor size, more well- and moderately differentiated tumors, a more superficial gross appearance, less scirrhous stromal reactions, more likely to have high FAK expression, and have less advanced pathologic tumor (T) category, node (N) category, and tumor, node, metastasis (TNM) stage and more distant metastases than patients with low PTEN expression. Multivariate analysis showed that PTEN/FAK expression status is an independent prognostic factor affecting overall survival (OS) and disease-free survival (DFS). Patients with PTEN(high)/FAK(low) had better OS and DFS, followed by those with PTEN(high)/FAK(high), those with PTEN(low)/FAK(low), and those with PTEN(low)/FAK(high) (OS: 83.3% versus 58.0% versus 46.2% versus 26.5%, respectively, P < 0.001; DFS: 83.3% versus 55.8% versus 30.8% versus 24.4%, respectively, P < 0.001).

Conclusions:

GC patients with high PTEN expression were more likely to have fewer tumor recurrences and a better prognosis than those with low PTEN expression. PTEN and FAK may have opposing effects on GC patient survival. Our results may have clinical impact on treatment of GC patients.

Inhibition of Rho-Associated Kinase 1/2 Attenuates Tumor Growth in Murine Gastric Cancer

Gastric cancer (GC) remains a malignant disease with high mortality. Patients are frequently diagnosed in advanced stages where survival prognosis is poor. Thus, there is high medical need to find novel drug targets and treatment strategies. Recently, the comprehensive molecular characterization of GC subtypes revealed mutations in the small GTPase RHOA as a hallmark of diffuse-type GC. RHOA activates RHO-associated protein kinases (ROCK1/2) which regulate cell contractility, migration and growth and thus may play a role in cancer. However, therapeutic benefit of RHO-pathway inhibition in GC has not been shown so far. The ROCK1/2 inhibitor 1-(5-isoquinoline sulfonyl)-homopiperazine (HA-1077, fasudil) is approved for cerebrovascular bleeding in patients. We therefore investigated whether fasudil (i.p., 10 mg/kg per day, 4 times per week, 4 weeks) inhibits tumor growth in a preclinical model of GC. Fasudil evoked cell death in human GC cells and reduced the tumor size in the stomach of CEA424-SV40 TAg transgenic mice. Small animal PET/CT confirmed preclinical efficacy. Mass spectrometry imaging identified a translatable biomarker for mouse GC and suggested rapid but incomplete in situ distribution of the drug to gastric tumor tissue. RHOA expression was increased in the neoplastic murine stomach compared with normal non-malignant gastric tissue, and fasudil reduced (auto) phosphorylation of ROCK2 at THR249 in vivo and in human GC cells in vitro. In sum, our data suggest that RHO-pathway inhibition may constitute a novel strategy for treatment of GC and that enhanced distribution of future ROCK inhibitors into tumor tissue may further improve efficacy.

Expressions of Ras Homolog Gene Family, Member A (RhoA) and Cyclooxygenase-2 (COX-2) Proteins in Early Gastric Cancer and Their Role in the Development of Gastric Cancer

Background

This research focused on detecting the expressions of RhoA and cyclooxygenase-2 (COX-2) proteins in early gastric cancer tissues and to explore their role in the development of gastric cancer.

Material/Methods

Surgically resected gastric cancer tissues and the paired normal paracancerous tissues were collected from 26 patients with early gastric cancer from January 2015 to November 2015. The expressions of RhoA and COX-2 proteins were detected by using RT-PCR and immunohistochemistry techniques, respectively. Cell proliferation and migration experiments were conducted on the RhoA-silenced A6-B9 cells and COX-2-silenced D7-B8 cells so as to discuss their role in the development of gastric cancer.

Results

Relative mRNA expressions of RhoA and COX-2 in the cancer tissues were 0.823±0.021 and 0.892±0.103, respectively, which showed significant differences compared to the normal cancerous tissues (0.295±0.014 and 0.129±0.037) (p<0.05). Immunohistochemical staining indicated that the expressions of RhoA and COX-2 proteins in tumor tissues were significantly upregulated as compared to normal cancerous tissues (p<0.05). Cell cloning and streaking assays showed that silencing of RhoA and COX-2 gene caused a considerable decline in the proliferation and migration capacities of the gastric cancer cells, respectively (p<0.05).

Conclusions

RhoA and COX-2 were upregulated in early gastric cancer tissues, which facilitated the proliferation and migration of gastric cancer cells. Both proteins may be used as potential markers for the diagnosis of early gastric cancer.

Gastrokine 1 inhibits gastric cancer cell migration and invasion by downregulating RhoA expression

BACKGROUND

We investigated whether GKN1, a gastric tumor suppressor, contributes to the progression of gastric cancer by regulating RhoA expression.

METHODS

We analyzed the expression of GKN1, RhoA, miR-185, and miR-34a in 35 gastric cancer tissues, and compared their expression with T category and TNM stage. Cell migration and invasion, as well as the expression of epithelial-to-mesenchymal transition (EMT)-related proteins, were assessed in GKN1- and RhoA small interfering RNA (siRhoA)-transfected and recombinant-GKN1-treated AGS and MKN1 gastric cancer cells.

RESULTS

Expression of RhoA protein and messenger RNA (mRNA) was increased in 15 (42.9 %) and 17 (48.6 %) of 35 gastric cancer tissues respectively, and was associated with higher T category and TNM stage. GKN1 expression was significantly decreased in 27 gastric cancers (77.1 %) with a higher T category, and was inversely correlated with RhoA mRNA expression. In AGS and MKN1 cells, GKN1 expression increased miR-185 and miR-34a expression and reduced RhoA mRNA and protein expression. A positive relationship between GKN1 and miR-34a and miR-185 expression and an inverse relationship between miR-34a and RhoA expression were observed in gastric cancer tissues. Cell migration and invasiveness were markedly decreased in GKN1- and siRhoA-transfected cells. GKN1 expression and silencing of RhoA decreased the expression of the proteins Snail, Slug, and vimentin. Furthermore, miR-185 and miR-34a silencing in MKN1 cells transfected with GKN1 stimulated cell migration and invasion, and increased the expression of EMT-related proteins.

CONCLUSION

Our data suggest that GKN1 may inhibit gastric cancer cell migration and invasion by downregulating RhoA expression in a miR-185- and miR-34a-dependent manner.

Differential role of Wnt signaling and base excision repair pathways in gastric adenocarcinoma aggressiveness

Aberrant activation of Wnt and base excision repair (BER) signaling pathways are implicated in tumor progression and chemotherapy resistance in gastric adenocarcinoma. This study was conducted to clarify the role of E2F6 and RhoA, components of the Wnt signaling pathway, and SMUG1, a component of the BER pathway in gastric adenocarcinoma. Expression levels and clinicopathological significance of three biomarkers, namely E2F6, RhoA, and SMUG1, as potential signaling molecules involved in tumorigenesis and aggressive behavior, were examined using tissue microarray. Our analysis showed a relative increase in the expression of E2F6 in gastric adenocarcinoma with no lymph node metastasis (χ ², P = 0.04 and OR, P = 0.08), while overexpression of RhoA and SMUG1 was found more often in the diffuse subtype of gastric adenocarcinoma as compared to the intestinal subtype (χ ², P = 0.05, OR, P = 0.08 and χ ², P = 0.001, OR, P = 0.009, respectively). Higher expression of RhoA was frequently seen in tumors with vascular invasion (χ ², P = 0.01 and OR, P = 0.01). In addition, increased expression of SMUG1 was found more often in poorly differentiated tumors (χ ², P = 0.01 and OR, P = 0.01). The distinct phenotype of E2F6^Low/SMUG1^High was more common in poorly differentiated tumors (P = 0.04) and with omental involvement (P = 0.01). The RhoA^High/SMUG1^High expression pattern was significantly more often found in diffuse subtype compared to the intestinal subtype (P = 0.001) as well as in poorly differentiated tumors (P = 0.004). The E2F6^Low/SMUG1^High and RhoA^High/SMUG1^High phenotypes can be considered as aggressive phenotypes of gastric adenocarcinoma. Our findings also demonstrated the synergistic effect of RhoA and SMUG1 in conferring tumor aggressiveness in diffuse subtype of gastric adenocarcinoma.

MiR-31 Regulates Rho-Associated Kinase-Myosin Light Chain (ROCK-MLC) Pathway and Inhibits Gastric Cancer Invasion: Roles of RhoA

Background

This study evaluated how the expression of miR-31 can be used to detect gastric cancer (GC) to help illuminate the role of miR-31 and RhoA in GC cells.

Material/Methods

We carried out our experiments using tissue specimens from 70 GC patients. The relative expression of miR-31 and RhoA mRNA in tissues and cells was detected by RT-PCR. The expression level of RhoA protein was detected by immunohistochemistry. GC cell line BGC-823 was transfected with six groups of vectors: blank group, NC (negative control) group, miR-31 mimics group, miR-31 mimics + RhoA group, miR-31 mimics + ROCK group, and miR-31 mimics + MLCK agonist group. AGS cells were also transfected with six groups of vectors: blank group, NC group, miR-31 inhibitor group, miR-31 inhibitor + RhoA siRNA group, miR-31 inhibitor + ROCK siRNA group, and miR-31 inhibitor + MLCK inhibitor group. Transwell assay was performed to detect the invasion and migration of cells. The protein expression in different transfected groups was detected using Western blotting.

Results

GC tissues exhibited significantly lower levels of miR-31 expression compared to pericarcinous tissues (p<0.01). Moreover, a significantly higher expression of RhoA in GC tissues was observed (p<0.05). MiR-31 inhibited RhoA expression by binding to 3′UTR of mRNA, whereas miR-31 mimics significantly decreased the number of invaded and migrated cells (p<0.05). The activation of RhoA, ROCK, and phosphorylation of MLC remarkably exacerbate the invasion and migration ability of GC cells (p<0.05).

Conclusions

We found miR-31 could downregulate the ROCK/MLC pathway by inhibiting the expression of RhoA in order to suppress the invasion and migration of GC cells.

The role of RhoA in vulvar squamous cell carcinoma: a carcinogenesis, progression, and target therapy marker

Ras homologue gene family member A (RhoA) is involved in tumor mobility, invasion, and metastasis. We detected RhoA expression in vulvar squamous cell carcinoma (VSCC) tissue, measured RhoA expression in the VSCC cell phenotype, and measured the expression of the relevant molecules after RhoA small interfering RNA (siRNA) transfection in SW962 cells. RhoA has a higher expression level in VSCC than normal vulva skin tissue and was positively associated with the International Federation of Gynecology and Obstetrics (FIGO) stage and differentiation; besides, VSCC patients with lymph node metastasis had higher positive RhoA expression. RhoA messenger RNA and protein expression was significantly reduced in the RhoA siRNA transfectants as compared with the negative control (NC) and mock-transfected cells (p < 0.05). The RhoA siRNA transfectants lead to low growth, G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppressed lamellipodia formation as compared to NC and mock-transfected cells. Besides, matrix metalloproteinase-2 (MMP2), MMP9, and cyclinA1 protein expression was downregulated, while that of Bax was upregulated in the RhoA siRNA transfectants (p < 0.05). SW962 cell proliferation rates were significantly lovastatin dose-dependent. Lovastatin caused G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppression of lamellipodia formation. Similar to the RhoA siRNA transfectants, lovastatin treatment downregulated RhoA, MMP2, MMP9, and cyclinA1 protein expression, while upregulating that of Bax as compared to that of the NC (p < 0.05). Abnormal RhoA expression in vulvar carcinoma is involved in tumor proliferation and invasion and may be a treatment target. The RhoA inhibitor lovastatin alters VSCC cell migration and proliferation and may be effective for treating VSCC.