Transglutaminase 3 suppresses proliferation and cisplatin resistance of cervical cancer cells by inactivation of the PI3K/AKT pathway

Recent studies have shown that dysregulation of transglutaminase 3 (TGM3) is related to the aggressive progression of several cancer types. Our study aimed to determine the function of TGM3 in cervical cancer (CC) tumorigenesis. Gene expression profiles GSE63514, GSE9750, GSE46857 and GSE67522 were obtained from the Gene Expression Omnibus (GEO) database. Overlapping differential expressed genes (DEGs) in CC were screened using GEO2R online tool and Venn diagram software. The Kaplan-Meier plotter was used to determine overall survival. TGM3 expression was analyzed based on GEO and The Cancer Genome Atlas (TCGA) databases, qRT-PCR and western blot analyses. Cell proliferation was evaluated by CCK-8 and EdU incorporation assays. The half-maximal inhibitory concentration (IC50) value of cisplatin and cell apoptosis was assessed by CCK-8 and TUNEL assays, respectively. P-glycoprotein (P-gp) expression and the changes of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway were examined using western blot analysis. We identified 3 overlapping DEGs, including TGM3, glutathione peroxidase 3 (GPX3), and alpha B-crystallin (CRYAB), which were downregulated in CC tissues. TGM3 expression was reduced in CC cells and related to the poor prognosis of CC patients. TGM3 overexpression retarded the proliferation, reduced IC50 value of cisplatin, accelerated cisplatin-induced apoptosis, and inhibited cisplatin-induced P-gp level in CC cells. Furthermore, TGM3 overexpression suppressed the PI3K/Akt pathway in CC cells. Moreover, treatment with 740Y-P, a PI3K activator, abolished the effect of TGM3 overexpression on proliferation and cisplatin resistance in CC cells. In conclusion, overexpression of TGM3 suppressed proliferation and cisplatin resistance in CC cells by blocking the PI3K/Akt pathway.

Clinical and immunological characteristics of TGM3 in pan-cancer: A potential prognostic biomarker

Background: Recent studies have identified that transglutaminases (TGMs) are involved in a widespread epigenetic modification in tumorigenesis. However, it remains unclear how transglutaminase 3 (TGM3) affects in pan-cancer. The present study aimed to explore the clinical and prognostic function of TGM3 in pan-cancer as well as to explore the relationship of TGM3 expression with clinical stage, survival rate, prognosis condition, immune infiltration and mutation indicators. Methods: The relevant data of tumors were obtained from The Cancer Genome Atlas (TCGA), TARGET, Cancer Cell Line Encyclopedia (CCLE) and Genotype-Tissue Expression (GTEx) databases. According to the Human Protein Atlas (HPA) and TIMER databases, we evaluated the protein expression levels of TGM3 in different organs and tissues as well as their association with immune cell infiltration and immunotherapeutic response in pan-cancers. Expression differences between normal and tumor tissues as well as survival and prognosis situation, clinical data characteristics, tumor mutational burden (TMB), microsatellite instability (MSI), and RNA methylation were also assessed. Oncogenic analyses were also evaluated by GSEA. Results: Compared to normal tissues, some tumor tissues had a lower expression level of TGM3, while other tumor tissues had a high expression level of TGM3. Further studies showed that high TGM3 expression had a certain risk impact on pan-cancer as high TGM3 expression levels were detrimental to the survival of several cancers, except for pancreatic cancer (PAAD). High expression level of TGM3 was also related to higher clinical stages in most cancers. The expression level of TGM3 was significantly negatively correlated with the expression of immune infiltration-related cells, including B cells, CD8+ T cells, CD4+ T cells, neutrophils, macrophages and dendritic cells (DCs). Furthermore, in most cancer types, TGM3 was inversely correlated with TMB, MSI, and methylation, suggesting that TGM3 expression can be used to assess potential therapeutic response, especially immune-related targeted therapy. GSEA analysis elucidated the biological and molecular function of TGM3 in various cancer types. Taken together, these bioinformatic analyses identified TGM3 as an important biomarker for clinical tumor prognosis and evaluation of treatment efficacy. Conclusion: We comprehensively analyzed the clinical characteristics, tumor stages, immune infiltration, methylation level, gene mutation, functional enrichment analysis and immunotherapeutic value of TGM3 in pan-cancer, providing implications for the function of TGM3 and its role in clinical treatment.

Circular RNA ciRS-7 promotes laryngeal squamous cell carcinoma development by inducing TGM3 hypermethylation via miR-432-5p/DNMT3B axis

OBJECTIVE

This work is to explore the mechanism by which circular RNA ciRS-7 affects laryngeal squamous cell carcinoma (LSCC).

METHODS

ciRS-7 expression in LSCC tissues was detected by qRT-PCR, and the association between ciRS-7 with clinicopathological features of LSCC patients was evaluated. HN-4 and UM-SCC-10A cells were transfected or cotransfected with si-ciRS-7, miR-432-5p inhibitor, LV-DNMT3B or si-TGM3. Then, the viability and aggressive nature of the cells were tested. The binding site between ciRS-7 and miR-432-5p or between miR-432-5p and DNMT3B was predicted and the targeting relationship was identified. The specific binding between ciRS-7 and miR-432-5p was further verified by AGO2 RIP assay. HN-4 cells transfected with si-ciRS-7 was injected into nude mice to induce xenograft tumors.

RESULTS

Higher ciRS-7 expression in LSCC tissues was closely associated with higher clinical stage, and exacerbated infiltration and lymph node metastasis in LSCC patients. Silencing ciRS-7 inhibited LSCC cell viability, epithelial-mesenchymal transition (EMT), and promoted the apoptosis. When miR-432-5p was inhibited or DNMT3B was overexpressed, the growth and EMT of LSCC cells were stimulated despite ciRS-7 silencing. Downregulation of ciRS-7 restrained the growth of xenograft tumors in vivo.

CONCLUSION

ciRS-7 promotes the progression of LSCC through increasing TGM3 methylation via miR-432-5p/DNMT3B axis.