Objectives: MICAL-L2, a member of the molecules interacting with the CasL (MICAL) family, was reported to be highly expressed in several types of cancers, however, the roles of MICAL-L2 in NSCLC pathogenesis remain to be explored. This study is designed to clarify the mechanisms by which MICAL-L2 participates in NSCLC cell proliferation.Materials and Methods: The expression levels of MICAL-L2 in human lung cancer samples were assessed by immunohistochemical staining. Cells were transfected with siRNA or plasmids to regulate MICAL-L2 expression. Cell proliferation was measured by EdU staining and CCK-8 assays. MICAL-L2 and phosphorylated/total c-Myc expression were examined by Western blotting analysis. Interaction between MICAL-L2 and c-Myc was assessed by immunofluorescence staining, Western blotting and co-immunoprecipitation assays. Western blotting, polyubiquitylation detection and protein stability assays were used to assess whether MICAL-L2 exerts its oncogenic effect via c-Myc.Results: We found that MICAL-L2 was highly expressed in human NSCLC. While overexpressing MICAL-L2 increased NSCLC cell proliferation, MICAL-L2 depletion decreased the proliferation of NSCLC cells, an effect that was linked to cell cycle arrest. MICAL-L2 physically interacted with the c-Myc protein and functioned to maintain nuclear c-Myc levels and prolonged its half-life. Knockdown of MICAL-L2 expression led to decreased c-Myc protein stability through accelerating polyubiquitylation of c-Myc and gave rise to c-Myc degradation. We further found that MICAL-L2 deubiquitinated c-Myc and blocked its degradation, presumably by inhibiting c-Myc phosphorylation at threonine residue 58.Conclusions: These results indicate that MICAL-L2 is a key regulator of c-Myc deubiquitination and stability in the nucleus, and this activity may be involved in promoting NSCLC cell proliferation.

Dynamic cytoskeletal rearrangements underlie the changes that occur during cell division in proliferating cells. MICAL2 has been reported to possess reactive oxygen species- (ROS-) generating properties and act as an important regulator of cytoskeletal dynamics. However, whether it plays a role in gastric cancer cell proliferation is not known. In the present study, we found that MICAL2 was highly expressed in gastric cancer tissues, and this high expression level was associated with carcinogenesis and poor overall survival in gastric cancer patients. The knockdown of MICAL2 led to cell cycle arrest in the S phase and attenuated cell proliferation. Concomitant with S-phase arrest, a decrease in CDK6 and cyclin D protein levels was observed. Furthermore, MICAL2 knockdown attenuated intracellular ROS generation, while MICAL2 overexpression led to a decrease in the p-YAP/YAP ratio and promoted YAP nuclear localization and cell proliferation, effects that were reversed by pretreatment with the ROS scavenger N-acetyl-L-cysteine (NAC) and SOD-mimetic drug tempol. We further found that MICAL2 induced Cdc42 activation, and activated Cdc42 mediated the effect of MICAL2 on YAP dephosphorylation and nuclear translocation. Collectively, our results showed that MICAL2 has a promotive effect on gastric cancer cell proliferation through ROS generation and Cdc42 activation, both of which independently contribute to YAP dephosphorylation and its nuclear translocation.

Background S100A2, a member of the S100 protein family, is abnormally expressed and plays a vital role in multiple cancers. However, little is known about the clinical significance of S100A2 in endometrial carcinoma. Methods Clinicopathological data were obtained from The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Gene Expression Omnibus (GEO), and Clinical Proteomic Tumor Analysis Consortium (CPTAC). First, the expression and prognostic value of different S100 family members in endometrial carcinoma were evaluated. Subsequently, the Kaplan–Meier plotter and Cox regression analysis were used to assess the prognostic significance of S100A2, while the association between S100A2 expression and clinical characteristics in endometrial carcinoma was also analyzed using logistic regression. A receiver operating characteristic (ROC) curve and a nomogram were constructed. The putative underlying cellular mechanisms were explored using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and gene set enrichment analysis (GSEA). Results Our results revealed that S100A2 expression was significantly higher in endometrial carcinoma tissue than in non-cancerous tissue at both the mRNA and protein levels. Analysis of Kaplan–Meier plotter data revealed that patients with high S100A2 expression had shorter overall survival (OS) and disease specific survival (DSS) compared with those of patients with low S100A2 expression. Multivariate Cox analysis further confirmed that high S100A2 expression was an independent risk factor for OS in patients with endometrial carcinoma. Other clinicopathologic features found to be related to worse prognosis in endometrial carcinoma included age, clinical stage, histologic grade, and tumor invasion. Importantly, ROC analysis also confirmed that S100A2 has a high diagnostic value in endometrial carcinoma. KEGG enrichment analysis and GSEA revealed that the estrogen and IL-17 signaling pathways were significantly upregulated in the high S100A2 expression group, in which estrogen response, JAK-STAT3, K-Ras, and TNFα/NF-κB were differentially enriched. Conclusions S100A2 plays an important role in endometrial carcinoma progression and may represent an independent diagnostic and prognostic biomarker for endometrial carcinoma.

Aims and Hypothesis: Cell migration is driven by the reorganization of the actin cytoskeleton. Although MICAL2 is known to mediate the oxidation of actin filaments to regulate F-actin dynamics, relatively few studies have investigated the potential role of MICAL2 during cancer cell migration.Methods: The migratory ability of gastric cancer cells was measured by wound healing and transwell assays. The relationship between MICAL2 expression and MRTF-A nuclear localization was analyzed using gene overexpression and knockdown strategies. The production of reactive oxygen species (ROS) was evaluated by DCFH-DA staining. mRNA and protein levels of MMP9 were measured using qPCR and immunoblotting analysis. The activities of CDC42 and RhoA were assessed using pulldown assays.Results: Depletion of MICAL2 markedly reduced gastric cancer cell migration. Mechanistically, silencing of MICAL2 inhibited the nuclear translocation of MRTF-A in response to EGF and serum stimulation, whereas the contents of MRTF-A remained unchanged. Further analysis showed that silencing of MICAL2 decreased the activation of CDC42 as well as mRNA and protein levels of MMP9. Ectopic expression of MICAL2 augmented MRTF-A levels in the nucleus, and promoted the activation of CDC42, MMP9 expression, and gastric cancer cell migration. Moreover, silencing of MRTF-A inhibited the CDC42 activation induced by overexpression of MICAL2. In addition, MICAL2-induced ROS generation contributed to the effect exerted by MICAL2 on MRTF-A nuclear translocation.Conclusion: Together, these results provide evidence that MICAL2 facilitates gastric cancer cell migration via positive regulation of nuclear translocation of MRTF-A and subsequent CDC42 activation and MMP9 expression.

Background Gastric cancer is a common and lethal human malignancy worldwide and cancer cell metastasis is the leading cause of cancer-related mortality. MICAL2, a flavoprotein monooxygenase, is an important regulator of epithelial-to-mesenchymal transition. The aim of this study was to explore the effects of MICAL2 on gastric cancer cell migration and determine the underlying molecular mechanisms. Methods Cell migration was examined by wound healing and transwell assays. Changes in E-cadherin/β-catenin signaling were determined by qPCR and analysis of cytoplasmic and nuclear protein fractions. E-cadherin/β-catenin binding was determined by co-immunoprecipitation assays. Cdc42 activity was examined by pulldown assay. Results MICAL2 was highly expressed in gastric cancer tissues. The knockdown of MICAL2 significantly attenuated migratory ability and β-catenin nuclear translocation in gastric cancer cells while LiCl treatment, an inhibitor of GSK3β, reversed these MICAL2 knockdown-induced effects. Meanwhile, E-cadherin expression was markedly enhanced in MICAL2-depleted cells. MICAL2 knockdown led to a significant attenuation of E-cadherin ubiquitination and degradation in a Cdc42-dependent manner, then enhanced E-cadherin/β-catenin binding, and reduced β-catenin nuclear translocation. Conclusions Together, our results indicated that MICAL2 promotes E-cadherin ubiquitination and degradation, leading to enhanced β-catenin signaling via the disruption of the E-cadherin/β-catenin complex and, consequently, the promotion of gastric cell migration.