MAP4 regulates Tctex-1 and promotes the migration of epidermal cells in hypoxia

MAP4 acts as an oncogene and prognostic marker and affects radioresistance by mediating epithelial-mesenchymal transition in lung adenocarcinoma

PURPOSE

To explore the effect of microtubule-associated protein 4 (MAP4) on lung adenocarcinoma cells in vitro and evaluate its prognostic value. Radioresistance, indicated by reduced efficiency of radiotherapy, is a key factor in treatment failure in lung adenocarcinoma (LADC). This study aims to explore the primary mechanism underlying the relationship between MAP4 and radiation resistance in lung adenocarcinoma.

METHODS

We analysed the expression of MAP4 in lung adenocarcinoma by real-time quantitative polymerase chain reaction (RT‒qPCR), immunohistochemistry (IHC) and bioinformatics online databases, evaluated the prognostic value of MAP4 in lung adenocarcinoma and studied its relationship with clinicopathological parameters. Cox regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis identified independent prognostic factors associated with lung adenocarcinoma that were used to construct a nomogram, internal validation was performed. We then evaluated the accuracy and clinical validity of the model using a receiver operating characteristic (ROC) curve, time-dependent C-index analysis, a calibration curve, and decision curve analysis (DCA). Scratch assays and transwell assays were used to explore the effect of MAP4 on the migration and invasion of lung adenocarcinoma cells. Bioinformatics analysis, RT‒qPCR, Cell Counting Kit-8 (CCK-8) assays and Western blot experiments were used to study the relationship between MAP4, epithelial-mesenchymal transition (EMT) and radiation resistance in lung adenocarcinoma.

RESULTS

MAP4 expression in lung adenocarcinoma tissues was significantly higher than that in adjacent normal lung tissues. High expression of MAP4 is associated with poorer overall survival (OS) in patients with lung adenocarcinoma. Univariate Cox regression analysis showed that pT stage, pN stage, TNM stage and MAP4 expression level were significantly associated with poorer OS in LADC patients. Multivariate Cox regression analysis and LASSO regression analysis showed that only the pT stage and MAP4 expression level were associated with LADC prognosis. The nomogram constructed based on the pT stage and MAP4 expression showed good predictive accuracy. ROC curves, corrected C-index values, calibration curves, and DCA results showed that the nomogram performed well in both the training and validation cohorts and had strong clinical applicability. The results of in vitro experiments showed that the downregulation of MAP4 significantly affected the migration and invasion of lung adenocarcinoma cells. MAP4 was strongly correlated with EMT-related markers. Further studies suggested that the downregulation of MAP4 can affect the viability of lung adenocarcinoma cells after irradiation and participate in the radiation resistance of lung adenocarcinoma cells by affecting EMT.

CONCLUSION

MAP4 is highly expressed in lung adenocarcinoma; it may affect prognosis by promoting the migration and invasion of cancer cells. We developed a nomogram including clinical factors and MAP4 expression that can be used for prognosis prediction in patients with lung adenocarcinoma. MAP4 participates in radiation resistance in lung adenocarcinoma by regulating the radiation-induced EMT process. MAP4 may serve as a biomarker for lung adenocarcinoma prognosis evaluation and as a new target for improving radiosensitivity.

Identification of DYNLT1 associated with proliferation, relapse, and metastasis in breast cancer

Background

Breast cancer (BC) is the most common malignant disease worldwide. Although the survival rate is improved in recent years, the prognosis is still bleak once recurrence and metastasis occur. It is vital to investigate more efficient biomarkers for predicting the metastasis and relapse of BC. DYNLT1 has been reported that participating in the progression of multiple cancers. However, there is still a lack of study about the correlation between DYNLT1 and BC.

Methods

In this study, we evaluated and validated the expression pattern and prognostic implication of DYNLT1 in BC with multiple public cohorts and BC tumor microarrays (TMAs) of paraffin-embedded tissues collected from the Affiliated Hospital of Jining Medical University. The response biomarkers for immune therapy, such as tumor mutational burden (TMB), between different DYNLT1 expression level BC samples were investigated using data from the TCGA-BRCA cohort utilizing public online tools. In addition, colony formation and transwell assay were conducted to verify the effects of DYNLT1 in BC cell line proliferation and invasion.

Results

The results demonstrated that DYNLT1 overexpressed in BC and predicted poor relapse-free survival in our own BC TMA cohort. In addition, DYNLT1 induced BC development by promoting MDA-MB-231 cell proliferation migration, and metastasis.

Conclusion

Altogether, our findings proposed that DYNLT1 could be a diagnostic and prognostic indicator in BC.

Microtubule-associated protein 4 promotes epithelial mesenchymal transition in hepatocellular cancer cells via regulating GSK3β/β-catenin pathway

Metastasis is a major obstacle in the treatment of hepatocellular carcinoma (HCC). Microtubule-associated protein 4 (MAP4) plays an important role as a coordinator between microtubules and microfilaments. However, the role of MAP4 in HCC migration and epithelial mesenchymal transition (EMT) is unclear. We compared the protein and mRNA levels of MAP4 in human HCC and adjacent normal tissues using western blotting, immunohistochemistry and RT-qPCR. The migration and invasion abilities and the levels of EMT markers (E-Cadherin, N-Cadherin, Vimentin, and Snail) were compared between MAP4-knockdown and MAP4-overexpressed HCC cells. Finally, we examined whether β-catenin and glycogen synthase kinase 3β (GSK3β) are involved in the stimulatory effects of MAP4 on HCC migration, invasion and EMT. The results revealed that MAP4 levels were higher in the HCC tissues than in the normal hepatic tissues. More importantly, MAP4 knockdown suppressed migration and invasion abilities and EMT processes in HCC cells, which were confirmed by the stimulatory effects of MAP4 overexpression on EMT processes in HCC cells. Further evidence demonstrated that the up-regulation of β-catenin activity induced by the interaction between MAP4 and GSK3β possibly accounted for the pro-migration and pro-EMT effects of MAP4 on HCC cells. Taken together, these results suggest that MAP4 promotes migration, invasion, and EMT in HCC cells by regulating the GSK3β/β-catenin pathway.

Research on the pathological mechanism of rectal adenocarcinoma based on DNA methylation

Colorectal cancer is one of the 3 most common cancers worldwide. In this study, a weighted network-based analysis method was proposed to explore the pathological mechanisms and prognostic targets of rectal adenocarcinoma (READ) at the deoxyribonucleic acid (DNA) methylation level. In this study, we downloaded clinical information and DNA methylation data from The Cancer Genome Atlas database. Differentially methylated gene analysis was used to identify the differential methylated genes in READ. Canonical correlation analysis was used to construct the weighted gene regulatory network for READ. Multilevel analysis and association analyses between gene modules and clinical information were used to mine key modules related to tumor metastasis evaluation. Genetic significance analysis was used to identify methylation sites in key modules. Finally, the importance of these methylation sites was confirmed using survival analysis. DNA methylation datasets from 90 cancer tissue samples and 6 paracancerous tissue samples were selected. A weighted gene regulatory network was constructed, and a multilevel algorithm was used to divide the gene co-expression network into 20 modules. From gene ontology enrichment analysis, characteristic M was related to biological processes such as the chemotaxis of fibroblast growth factors and the activation and regulation of immune cells etc and characteristic N was associated with the regulation of cytoskeleton formation, mainly microtubules and flagella, regulation of synapses, and regulation of cell mitosis. Based on the results of survival analysis, 7 key methylation sites were found closely correlated to the survival rate of READ, such as cg04441191 (microtubule-associated protein 4 [MAP4]), cg05658717 (KSR2), cg09622330 (GRIN2A), cg10698404 (YWHAG), cg17047993 (SPAG9), cg24504843 (CEP135), and cg24531267 (CEP250). Mutational and transcriptomic level studies revealed significant differences in DNA methylation, single nucleotide polymorphism, and transcript levels between YWHAG and MAP4 in normal tissues compared to tumor tissues, and differential expression of the 2 proteins in immunohistochemistry. Therefore, potential targeting drugs were screened for these 2 proteins for molecular docking, and artenimol was found to bind to MAP4 protein and 27-hydroxycholesterol to YWHAG. Our study found that key methylation sites played an important role in tumor metastasis and were associated with the prognosis of READ. Mutations and methylation may jointly regulate the transcription and translation of related genes, which in turn affect cancer progression. This may provide some new potential therapeutic targets and thoughts for the prognosis of READ.

Identification and Validation of a Prognostic Signature Based on Methylation Profiles and Methylation-Driven Gene DAB2 as a Prognostic Biomarker in Differentiated Thyroid Carcinoma

Recurrence is the major death cause of differentiated thyroid carcinoma (DTC), and a better understanding of recurrence risk at early stage may lead to make the optimal medical decision to improve patients’ prognosis. The 2015 American Thyroid Association (ATA) risk stratification system primary based on clinic-pathologic features is the most commonly used to describe the initial risk of persistent/recurrent disease. Besides, multiple prognostics models based on multigenes expression profiles have been developed to predict the recurrence risk of DTC patients. Recent evidences indicated that aberrant DNA methylation is involved in the initiation and progression of DTC and can be useful biomarkers for clinical diagnosis and prognosis prediction of DTC. Therefore, there is a need for integrating gene methylation feature to assess the recurrence risk of DTC. Gene methylation profile from The Cancer Genome Atlas (TCGA) was used to construct a recurrence risk model of DTC by successively performed univariate Cox regression, LASSO regression, and multivariate Cox regression. Two Gene Expression Omnibus (GEO) methylation cohorts of DTC were utilized to validate the predictive value of the methylation profiles model as external cohort by receiver operating characteristic (ROC) curve and survival analysis. Besides, CCK-8, colony-formation assay, transwell, and scratch-wound assay were used to investigate the biological significance of critical gene in the model. In our study, we constructed and validated a prognostic signature based on methylation profiles of SPTA1, APCS, and DAB2 and constructed a nomogram based on the methylation-related model, age, and AJCC_T stage that could provide evidence for the long-term treatment and management of DTC patients. Besides, in vitro experiments showed that DAB2 inhibited proliferation, colony-formation, and migration of BCPAP cells and the gene set enrichment analysis and immune infiltration analysis showed that DAB2 may promote antitumor immunity in DTC. In conclusion, promoter hypermethylation and loss expression of DAB2 in DTC may be a biomarker of unfavorable prognosis and poor response to immune therapy.