Identification of a cisplatin resistant-based prognostic immune related gene signature in MIBC

Cisplatin resistance plays a significant role in the dismal prognosis and progression of muscle-invasive bladder cancer (MIBC). However, the strategies to predict prognosis and cisplatin resistance are inefficient, and it remains unclear whether cisplatin resistance is associated with tumor immunity. In this study, we integrated the transcriptional data from cisplatin-resistant cell lines and a TCGA-MIBC cohort to establish cisplatin-resistance-related cluster classification and a cisplatin-resistance-related gene risk score (CRRGRS). Kaplan-Meier survival curves showed that compared with those in low CRRGRS group, MIBC patients belonging to high CRRGRS group had worse prognosis in TCGA-MIBC cohort and external GEO cohorts. Meanwhile, CRRGRS was able to help forecast chemotherapy and immunotherapy response of MIBC patients in the TGCA cohort and IMvigor210 cohort. Moreover, compared with the low CRRGRS group, the high CRRGS group possessed a relatively immunosuppressive "cold tumor" phenotype with a higher tumor immune dysfunction and exclusion (TIDE) score, ESTIMATE score, stromal score and immune score and a lower immunophenoscore (IPS) score. The upregulated expression levels of immune checkpoint genes, including PD-1, PD-L1 and CTLA4, in the high CRRGRS group also further indicated that a relative immunosuppressive tumor microenvironment may exist in MIBC patients belonging to high CRRGRS group. In addition, we integrated CRRGRS and clinical characteristics with prognostic value to develop a nomogram, which could help forecast overall survival of MIBC patients. Furthermore, DIAPH3 was identified as a regulator of proliferation and cisplatin resistance in MIBC. The expression of DIAPH3 was increased in cisplatin-resistant cell lines and chemotherapy-unsensitive people. Further mechanism exploration revealed that DIAPH3 facilitated tumor proliferation and cisplatin resistance by regulating the NF-kB and epithelial-mesenchymal transition (EMT) pathways. In conclusion, the comprehensive investigations of CRRGRS increased the understanding of cisplatin resistance and provided promising insights to restrain tumor growth and overcome chemoresistance by targeting DIAPH3.

Role of MEK1 and DIAPH3 expression in colorectal adenoma-carcinoma sequence

BACKGROUND

It is well established that most colorectal carcinomas arise from conventional adenomas through the adenoma-carcinoma sequence (ACS) model. mitogen-activated protein kinases (MAPKs) pathway has been reported as a crucial player in tumorigenesis. The MAPK signaling pathway is activated by different extracellular signals involving the "mitogen-activated/extracellular signal-regulated kinase 1 (MEK1)", and this induces the expression of genes involved in proliferation and cellular transformation. Diaphanous-related formin-3 (DIAPH3) acts as a potential metastasis regulator through inhibiting the cellular transition to amoeboid behavior in different cancer types.

OBJECTIVE

The aim of the study was to investigate the pattern of immunohistochemical expression of MEK1 and DIAPH3 in colorectal adenoma (CRA) and corresponding colorectal carcinoma (CRC) specimens.

METHODS

The immunohistochemical expression of DIAPH3 and MEK1 was examined in 43 cases of CRC and their associated adenomas using tissue microarray technique.

RESULTS

MEK1 was overexpressed in 23 CRC cases (53.5%) and in 20 CRA cases (46.5%). DIAPH3 was overexpressed in 11 CRA cases (about 29%) which were significantly lower than CRC (22 cases; 58%) (P = 0.011). Both MEK1 and DIAPH3 overexpression were significantly correlated in CRC (P = 0.009) and CRA cases (P = 0.002). Tumors with MEK1 overexpression had a significantly higher tumor grade (P = 0.050) and perineural invasion (P = 0.017).

CONCLUSIONS

Both MEK1 and DIAPH3 are overexpressed across colorectal ACS with strong correlation between them. This co- expression suggests a possible synergistic effect of MEK1 and DIAPH-3 in colorectal ACS. Further large-scale studies are required to investigate the potential functional aspects of MEK1 and DIAPH3 in ACS and their involvement in tumor initiation and the metastatic process.

The pan-cancer analysis identified DIAPH3 as a diagnostic biomarker of clinical cancer

OBJECTIVE

This study aimed to determine prognostic biomarkers of cervical cancer by pan-cancer analysis.

MATERIALS AND METHODS

Common differentially expressed genes in Gene Expression Omnibus and The Cancer Genome Atlas (TCGA) database were demonstrated using R software analysis, and these genes were enriched by the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology. Genes with prognostic value were identified by least absolute contraction and selection regression, Cox regression, and survival analysis, and pan-cancer analysis was conducted using the Tumor Immune Estimation Resource database and TCGA database. Western blot, qRT-PCR, and immunohistochemistry were used to preliminarily verify its expression in cervical cancer (S1).

RESULTS

The prognostic marker Diaphanous Related Formin 3 (DIAPH3) was obtained from us. The enrichment analysis revealed that DIAPH3 was involved in tumor proliferation, invasion, and inflammation. The pan-cancer analysis revealed that it was highly expressed in various cancers. Immune infiltration analysis revealed that its expression was related to B cells, effector T cells, and macrophage infiltration; however, immune checkpoint correlation analysis and tumor mutation burden analysis revealed the correlation between gene expression and immunotherapy. The expression of DIAPH3 in cervical cancer was significantly different from that in normal cervical tissues.

CONCLUSION

The expression of DIAPH3 in cervical cancer was significantly increased, which may be related to the proliferation, metastasis, immune invasion, and immunotherapy of cervical cancer.

Diaphanous-related formin subfamily: Novel prognostic biomarkers and tumor microenvironment regulators for pancreatic adenocarcinoma

The diaphanous-related formin subfamily includes diaphanous homolog 1 (DIAPH1), DIAPH2, and DIAPH3. DIAPHs play a role in the regulation of actin nucleation and polymerization and in microtubule stability. DIAPH3 also regulates the assembly and bipolarity of mitotic spindles. Accumulating evidence has shown that DIAPHs are anomalously regulated during malignancy. In this study, we reviewed The Cancer Genome Atlas database and found that DIAPHs are abundantly expressed in pancreatic adenocarcinoma (PAAD). Furthermore, we analyzed the gene alteration profiles, protein expression, prognosis, and immune reactivity of DIAPHs in PAAD using data from several well-established databases. In addition, we conducted gene set enrichment analysis to investigate the potential mechanisms underlying the roles of DIAPHs in the carcinogenesis of PAAD. Finally, we performed the experimental validation of DIAPHs expression in several pancreatic cancer cell lines and tissues of patients. This study demonstrated significant correlations between DIAPHs expression and clinical prognosis, oncogenic signature gene sets, T helper 2 cell infiltration, plasmacytoid dendritic cell infiltration, myeloid-derived suppressor cell infiltration, ImmunoScore, and immune checkpoints in PAAD. These data may provide important information regarding the role and mechanisms of DIAPHs in tumorigenesis and PAAD immunotherapy.

Role of Cytoskeletal Diaphanous-Related Formins in Hearing Loss

Hearing relies on the proper functioning of auditory hair cells and on actin-based cytoskeletal structures. Diaphanous-related formins (DRFs) are evolutionarily conserved cytoskeletal proteins that regulate the nucleation of linear unbranched actin filaments. They play key roles during metazoan development, and they seem particularly pivotal for the correct physiology of the reproductive and auditory systems. Indeed, in Drosophila melanogaster, a single diaphanous (dia) gene is present, and mutants show sterility and impaired response to sound. Vertebrates, instead, have three orthologs of the diaphanous gene: DIAPH1, DIAPH2, and DIAPH3. In humans, defects in DIAPH1 and DIAPH3 have been associated with different types of hearing loss. In particular, heterozygous mutations in DIAPH1 are responsible for autosomal dominant deafness with or without thrombocytopenia (DFNA1, MIM #124900), whereas regulatory mutations inducing the overexpression of DIAPH3 cause autosomal dominant auditory neuropathy 1 (AUNA1, MIM #609129). Here, we provide an overview of the expression and function of DRFs in normal hearing and deafness.

DIAPH3 is a prognostic biomarker and inhibit colorectal cancer progression through maintaining EGFR degradation

BACKGROUND

Actin cytoskeleton is connected with the processes of cell proliferation and migration in colorectal cancer (CRC). However, it is unknown how to accomplish these adjustments in CRC by actin cytoskeleton genes (ACGs) and here we investigated the role of hub prognosis-related ACGs-Diaphanous-related formin 3 (DIAPH3) in CRC, as a potential, novel target.

METHODS

The ACGs gene set from the Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to group CRC patients and select prognosis-related ACGs by univariate and multivariate Cox regression for constructing prognostic model. Next, we tested hub prognosis-related ACGs- DIAPH3 expression in CRC and clarified the role of DIAPH3 by shRNA constructs in KM12 and SW480. Activation of EGFR was analyzed by western blot and immunofluorescence.

RESULTS

The results showed that actin cytoskeleton function is a significant prognostic factor for CRC patients and related to clinicopathological characteristics such as T stage and lymph node metastasis. A prognostic model constructed by four prognosis-related ACGs has a moderate intensity to 1-year Survival (AUC = 0.71). And hub prognosis-related ACGs DIAPH3 is downregulated in CRC. Knockdown of DIAPH3 could promote the proliferation and migration capacity of CRC. In addition, DIAPH3-silenced cells increase EGFR phosphorylation by inhibiting EGFR transportation to lysosome.

CONCLUSIONS

ACGs play a significant role in tumor invasion and have the potential to predict the prognosis of CRC. Prognosis-related ACGs DIAPH3 might be a new prognostic biomarker and DIAPH3 could inhibit CRC progression through maintaining EGFR degradation.

Nonredundant roles of DIAPHs in primary ciliogenesis

Primary cilia are hubs for several signaling pathways, and disruption in cilia function and formation leads to a range of diseases collectively known as ciliopathies. Both ciliogenesis and cilia maintenance depend on vesicle trafficking along a network of microtubules and actin filaments toward the basal body. The DIAPH (Diaphanous-related) family of formins promote both actin polymerization and microtubule (MT) stability. Recently, we showed that the formin DIAPH1 is involved in ciliogenesis. However, the role of other DIAPH family members in ciliogenesis had not been investigated. Here we show that depletion of either DIAPH2 or DIAPH3 also disrupted ciliogenesis and cilia length. DIAPH3 depletion also reduced trafficking within cilia. To specifically examine the role of DIAPH3 at the base, we used fused full-length DIAPH3 to centrin, which targeted DIAPH3 to the basal body, causing increased trafficking to the ciliary base, an increase in cilia length, and formation of bulbs at the tips of cilia. Additionally, we confirmed that the microtubule-stabilizing properties of DIAPH3 are important for its cilia length functions and trafficking. These results indicate the importance of DIAPH proteins in regulating cilia maintenance. Moreover, defects in ciliogenesis caused by DIAPH depletion could only be rescued by expression of the specific family member depleted, indicating nonredundant roles for these proteins.

DIAPH3 promotes pancreatic cancer progression by activating selenoprotein TrxR1-mediated antioxidant effects

Pancreatic cancer is a highly malignant tumour of the digestive tract which is difficult to diagnose and treat. Approximately 90% of cases arise from ductal adenocarcinoma of the glandular epithelium. The morbidity and mortality of the disease have increased significantly in recent years. Its 5‐year survival rate is <1% and has one of the worst prognoses amongst malignant tumours. Pancreatic cancer has a low rate of early‐stage diagnosis, high surgical mortality and low cure rate. Selenium compounds produced by selenoamino acid metabolism may promote a large amount of oxidative stress and subsequent unfolded reactions and endoplasmic reticulum stress by consuming the NADPH in cells, and eventually lead to apoptosis, necrosis or necrotic cell death. In this study, we first identified DIAPH3 as a highly expressed protein in the tissues of patients with pancreatic cancer, and confirmed that DIAPH3 promoted the proliferation, anchorage‐independent growth and invasion of pancreatic cancer cells using overexpression and interference experiments. Secondly, bioinformatics data mining showed that the potential proteins interacted with DIAPH3 were involved in selenoamino acid metabolism regulation. Selenium may be incorporated into selenoprotein synthesis such as TrxR1 and GPX4, which direct reduction of hydroperoxides or resist ferroptosis, respectively. Our following validation confirmed that DIAPH3 promoted selenium content and interacted with the selenoprotein RPL6, a ribosome protein subunit involved in selenoamino acid metabolism. In addition, we verified that DIAPH3 could down‐regulate cellular ROS level via up‐regulating TrxR1 expression. Finally, nude mice xenograft model experimental results demonstrate DIAPH3 knock down could decrease tumour growth and TrxR1 expression and ROS levels in vivo. Collectively, our observations indicate DIAPH3 could promote pancreatic cancer progression by activating selenoprotein TrxR1‐mediated antioxidant effects.

DIAPH3 promotes the tumorigenesis of lung adenocarcinoma

Aberrant activation of MEKK-MEK-ERK signaling is frequently observed in lung cancer. Several inhibitors, which target this pathway, have shown clinical potential for the lung cancer treatment. Better understanding the regulation of this pathway would help the development of treatment strategies. In this study, we have identified the DIAPH3 as an up-regulated gene in lung adenocarcinoma. DIAPH3 promoted the growth of lung cancer cells both in the liquid culture and in the soft agar, and knockdown DIAPH3 inhibited the tumorigenesis both in the nude mice and in the de novo mouse model. In the molecular mechanism study, DIAPH3 was identified as the binding protein of STK38, impaired the interaction between STK38 and MEKK, and activated ERK signaling. Taken together, this study demonstrated the oncogenic roles of DIAPH3 in the tumorigenesis of lung cancer by interacting with STK38.

DIAPH3 promoted the growth, migration and metastasis of hepatocellular carcinoma cells by activating beta-catenin/TCF signaling

The enhanced ability of cancer cell migration and metastasis is the major cause for the cancer-related death of hepatocellular carcinoma (HCC). Better understanding the mechanisms for the motility of cancer cells will benefit the treatment. Diaphanous-related formin 3 (DIAPH3) has been reported to regulate the motility of cells by remodeling the cytoskeleton. However, the mechanism through which DIAPH3 regulated the motility of cancer cells remains largely unknown. In this study, we have shown that the expression of DIAPH3 was up-regulated in HCC. DIAPH3 positively regulated the growth, migration, colony formation, epithelia mesenchymal transition, and metastasis of HCC cells. Mechanically, DIAPH3 activated the beta-catenin/TCF signaling by binding HSP90 and disrupting the interaction between GSK3beta and HSP90. Taken together, our study demonstrated the oncogenic activity of DIAPH3 in the progression of HCC and suggested that PDIAPH3 might be a therapeutic target.