RNF2 E3 or Not to E3: Dual Roles of RNF2 Overexpression in Melanoma

Prognostic biomarkers and molecular pathways mediating Helicobacter pylori–induced gastric cancer: a network-biology approach

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori–induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori–induced cancer compared with the H. pylori–positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori–induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori–induced GC. However, experimental validation is necessary in the future.

Enhanced intratumoral expression of RNF2 is a favorable prognostic factor for patients with cutaneous melanoma?

Recent studies involving melanoma cell lines suggest that enhanced expression of epigenetic regulator RNF2 supports proliferation and promotes metastasis. However, it is not clear to what extent those data apply to disease progression and prognosis for melanoma patients. Therefore the aim of the present study was to assess the prognostic power of RNF2 intratumoral expression by melanoma cells.

RNF2 was detected immunohistochemically in standard formalin-fixed paraffin-embedded samples of 9 benign nevi, 60 melanomas and 24 nodal metastases.

The lowest percentage of RNF2-positive melanocytes found in nevi was comparable to expression levels in normal skin. The RNF2 expression found in melanomas was significantly higher and it was even more enhanced in metastases. The increased occurrence of RNF2 expressing cells was positively correlated with longer patients’ overall survival. Moreover, a negative correlation was found between intratumoral RNF2 expression and number of generated metastatic lesions.

Our data indicate that development of melanoma is associated with significant changes in RNF2 intratumoral expression and imply that at least for some patients the enhancement of the expression levels of RNF2 in both primary and metastatic lesions may be considered a favorable prognostic factor in melanoma.

RNF185 modulates JWA ubiquitination and promotes gastric cancer metastasis

Gastric cancer (GC) is one of the most common malignant cancers worldwide. Metastasis leads to poor prognoses in GC patients in advanced stages. Our previous studies have demonstrated that JWA functions as a tumour suppressor and that low expression of JWA in GC tissues is significantly correlated with shorter overall survival (OS) as well as with advanced clinicopathologic features in patients. However, the mechanism of dysregulation of JWA in cancers is not clear. In the present study, we found that an E3 ubiquitin ligase, RNF185, directly interacted with JWA and promoted its ubiquitination at the K158 site, resulting in subsequent degradation. Moreover, the protein level of RNF185 was negatively correlated with JWA in tumour tissues from GC patients. High RNF185 expression was significantly correlated with shorter OS. Additionally, increased RNF185 expression facilitated GC cell migration in vitro and promoted GC metastasis in vivo by downregulating JWA expression. However, this effect was reversed by replenishment of JWA. In conclusion, our findings highlight the following: (1) RNF185 promotes GC metastasis by mediating JWA degradation via a ubiquitin-proteasome pathway; (2) the K158 site of JWA is essential for its ubiquitination in GC cells. These findings suggest that RNF185 is a novel candidate prognostic marker and potential therapeutic target for GC.