The expression of FAT1 is associated with overall survival in children with medulloblastoma

FAT1 Upregulates in Oral Squamous Cell Carcinoma and Promotes Cell Proliferation via Cell Cycle and DNA Repair

Objective

Previous studies have revealed that FAT atypical cadherin 1 (FAT1) plays a tumor-suppressive or oncogenic role in a context-dependent manner in various cancers. However, the functions of FAT1 are ambiguous in tumorigenesis owing to inconsistent research in oral squamous cell carcinoma (OSCC). The present study aimed at gaining an insight into the role of FAT1 in the tumor genesis and development.

Methods

The expression, mutant, and survival data analyses were done using data from The Cancer Genome Atlas (TCGA), the Gene Expression Omnibus (GEO), and the Clinical Proteomic Tumor Analysis Consortium (CPTAC) database, verified with clinical samples via real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunohistochemical (IHC) staining. OSCC cells transfected with siRNA were employed for in vitro assessment in cell proliferation, apoptosis, and migration ability in appropriate ways. The underlying mechanism was explored by RNA sequencing after FAT1 silencing.

Results

Overall, FAT1 significantly increased in OSCC with a poor prognosis outcome. The in vitro experiment showed the promoting effect of FAT1 in the proliferation and migration of OSCC cells. FAT1 can also inhibit both the early and late apoptosis of OSCC cells. RNA-sequencing analysis of FAT1 silencing revealed that the cell cycle, DNA replication, and some core genes (MCM2, MCM5, CCNE1 SPC24, MYBL2, KIF2C) may be the potential mechanism in OSCC.

Conclusions

FAT1 may act as an oncogene in OSCC with potential mechanism influencing the cell cycle and DNA repair.

BRCA2 deficiency increases sensitivity of medulloblastoma to Olaparib by inhibiting RAD51-mediated DNA damage repair system

PURPOSE

BRCA2 defect exists in glioma and regulates drug resistance of glioma to chemotherapy. However, its role in medulloblastoma and the mechanism is not known. To investigate the effects of BRCA2 deficiency combined with Olaparib in medulloblastoma and the mechanism.

METHODS

BRCA2 was knocked down by RNAi technology and cell proliferation was detected by CCK-8 assay. Cell apoptosis was determined by FACS analysis when the in vivo role of BRCA2 was explored with xenograft mice model. Western blotting technology was used to explore the mechanism of BRCA2.

RESULTS

Knockdown of BRCA2 enhanced the inhibitory effect of Olaparib on proliferation of Daoy and LN229 cells. The inhibition rate of Olaparib on Daoy or LN229 cells was 61.1%, 66.03% in shBRCA2 group, while it was 42.9%, 41.1% in shNC group. Overexpression of RAD51 partially reversed the effect of shBRCA2. In Daoy cells, apoptotic rate was 26.9% in Olaparib group and 58.9% in Olaparib/shBRCA2 group. However, it was 33.4% after RAD51 was overexpressed. It was the same in LN229 cells. In xenograft mice model, tumor volume in Olaparib and Olaparib/shBRCA2 group was 376.12 and 84.95mm³ when tumor weight was 0.46 g and 0.12 g. In addition, the level of RAD51, RAD50, MRE11, and NBS was increased by Olaparib alone but decreased reversely after knockdown of BRCA2 in Daoy cells.

CONCLUSIONS

Knockdown of BRCA2 increases the sensitivity of medulloblastoma cells to Olaparib and strengthens the efficacy of Olaparib in vitro and in vivo. Knockdown of BRCA2 causes DNA damage repair by regulating RAD51-mediated signaling pathway in Daoy cells.

Risk Factors for Survival in Patients With Medulloblastoma: A Systematic Review and Meta-Analysis

Background

Conventional parameters show limited and unreliable correlations with medulloblastoma prognosis.

Aim

To evaluate the factors influencing overall survival (OS), event-free survival (EFS), and progression-free survival (PFS) in patients with medulloblastoma.

Methods

PubMed, EMBASE, the Cochrane Library, and Web of Science were searched for studies published up to May 2021. The associations between various clinical and treatment factors and survival parameters were assessed.

Results

Twenty-nine studies (8455 patients) were included. Desmoplastic medulloblastoma (HR=0.41, 95%CI: 0.31-0.56), M0 disease (HR=2.07, 95%CI: 1.48-2.89), WNT, SSH, group 4 (all P<0.05 vs. group 3), GTR vs. STR (HR=1.37, 95%CI: 1.04-1.08), radiotherapy (HR=0.45, 95%CI: 0.20-0.80), craniospinal irradiation (HR=0.49, 95%CI: 0.38-0.64), and high 5hmC levels (HR=2.90, 95%CI: 1.85-4.55) were associated with a better OS. WNT, SSH, group 4 (all P<0.05 vs. group 3), residual tumor ≤1.5 cm2 (HR=2.08, 95%CI: 1.18-3.68), GTR vs. STR (HR=1.31, 95%CI: 1.03-1.68), craniospinal irradiation (HR=0.46, 95%CI: 0.37-0.57), high 5hmC levels (HR=3.10, 95%CI: 2.01-4.76), and <49 days between resection and radiotherapy (HR=2.54, 95%CI: 1.48-4.37) were associated with better PFS. Classic vs. desmoplastic medulloblastoma (HR=1.81, 95%CI: 1.04-3.16), SSH, WNT (both P<0.05 vs, non-SSH/non-WNT), GTR vs. STR (HR=2.01, 95%CI: 1.42-2.85), and radiotherapy (HR=0.31, 95%CI: 0.15-0.64) were associated with a better EFS.

Conclusion

Histology, molecular subgroup, GTR, and radiotherapy are significantly associated with survival parameters in patients with medulloblastoma. Nevertheless, high-quality prospective cohort studies are necessary to improve the conclusions.

Role of FAT1 in health and disease

FAT atypical cadherin 1 (FAT1), which encodes a protocadherin, is one of the most frequently mutated genes in human cancer. Over the past 20 years, the role of FAT1 in tissue growth and in the development of diseases has been extensively studied. There is definitive evidence that FAT1 serves a substantial role in the maintenance of organs and development, and its expression appears to be tissue-specific. FAT1 activates a variety of signaling pathways through protein-protein interactions, including the Wnt/β-catenin, Hippo and MAPK/ERK signaling pathways, which affect cell proliferation, migration and invasion. Abnormal FAT1 expression may lead to the development of tumors and may affect prognosis. Therefore, FAT1 may have potential in tumor therapy. The structural and functional changes mediated by FAT1, its tissue distribution and changes in FAT1 expression in human diseases are described in the present review, which provides further insight for understanding the role of FAT1 in development and disease.

FHOD3 promotes carcinogenesis by regulating RhoA/ROCK1/LIMK1 signaling pathway in medulloblastoma

PURPOSE

Medulloblastoma (MB) is a malignant brain disease in young children. The overall survival of MB patients is disappointing due to absence of effective therapeutics and this could be attributed to the lack of molecular mechanism underlying MB. FHOD3 was an important gene during cardio-genesis and was reported to promote cell migration in cancer. However, its role in MB is not clear to date.

METHODS

RT-qPCR and IHC analysis were used to determine expression of FHOD3. Survival curve was drawn by K-M analysis. FHOD3 was knocked down by RNAi technology. The effects of FHOD3 on medulloblastoma cells were determined by CCK-8 assay, colony formation assay, transwell assay and FACs analysis.

RESULTS

FHOD3 expression increased by 1.5 fold in tumor tissues compared to the control and IHC analysis further confirmed strong expression of FHOD3 in medulloblastoma tissues. Then higher FHOD3 expression was associated with shorter survival time in MB patients (13.0 months versus 43.8 months). In medulloblastoma cells such as Daoy and D283med, FHOD3 also displayed abundant expression. When FHOD3 was knocked down, the ability of cell proliferation and colony formation was reduced over greatly. The capability of cell migration and invasion was also inhibited significantly. However, cell apoptotic rate increased significantly reversely. Mechanistically, the phosphorylation level of RhoA, ROCK1, and LIMK1 was decreased when FHOD3 was knocked down but increased reversely when FHOD3 was over-expressed in Daoy cells.

CONCLUSIONS

FHOD3 was associated with overall survival time in medulloblastoma patients and was essential to cell proliferation, growth and survival in medulloblastoma and might regulates activation of RhoA/ROCK1/LIMK1 signaling pathway.

Effect of FAT1 gene expression on the prognosis of medulloblastoma in children: A protocol for systematic review and meta-analysis

BACKGROUND

It was reported that cloning human adipose atypical cadherin 1 (FAT1) has an effect on the prognosis of medulloblastoma (MB), while the conclusion still needs to be further proved. Therefore, this study attempted to explore the effect of the high expression of FAT1 on the prognosis of MB children.

METHODS

The database was retrieved from China National Knowledge Infrastructure (CNKI), Chinese Biomedical literature Database (CBM), Chinese Scientific and Journal Database (VIP), Wan Fang database, PubMed, and EMBASE. Hazard ratios (HRs) and its 95% confidence intervals (CIs) were applied to assess the prognostic effect of FAT1 on overall survival (OS) and disease-free survival (DFS). RevMan 5.3 and STATA 16.0 software were used to perform the meta-analysis.

RESULTS

The results of the study would be published in peer-reviewed journals or at relevant meetings.

CONCLUSION

Our findings revealed the effect of the high expression of FAT1 on the prognosis of MB children. Such studies may find a new prognostic marker for MB children and help clinicians and health professionals make clinical decisions.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/5FN8M.

RBM5 Acts as Tumor Suppressor in Medulloblastoma through Regulating Wnt/β-Catenin Signaling

INTRODUCTION

RBM5 acts as a tumor suppressor gene in lung and breast cancers; however, its role in the pathogenesis of medulloblastoma (MB) remains unclear. We previously identified 4 RBM5 mutations in whole exome sequencing analysis of 40 MB patients. This study examined the role of RBM5 in MB progression.

METHODS

The expression patterns of RBM5 in tissues of 40 MB patients were analyzed using immunohistochemistry. Associations between RBM5 expression and overall survival (OS) were evaluated using Kaplan-Meier analysis. The RBM5 role in Daoy cells' proliferation, migration, and Wnt/β-catenin signaling was analyzed after RBM5 knockdown and overexpression.

RESULTS

The expression level of RBM5 mRNA and protein was significantly lower in MB than that in adjacent normal control tissues, and low RBM5 expression was significantly associated with reduced OS (p = 0.034). RBM5 knockdown induced Daoy and ONS-76 cells proliferation, while RBM5 overexpression repressed cell proliferation and migration in vitro (all p < 0.05). β-Catenin, LEF1, and cyclin D1 mRNA levels were upregulated, while DKK1 expression was downregulated in Daoy cells following RBM5 knockdown.

CONCLUSION

RBM5 may function as a tumor suppressor in MB by regulating Wnt/β-catenin signaling, and its reduced expression is associated with lower OS.

SMAD4 Somatic Mutations in Head and Neck Carcinoma Are Associated With Tumor Progression

As the incidence and the mortality rate of head and neck squamous cell carcinoma (HNSCC) is increasing worldwide, gaining knowledge about the genomic changes which happen in the carcinogenesis of HNSCC is essential for the diagnosis and therapy of the disease. SMAD4 (DPC4) is a tumor suppressor gene. It is located at chromosome 18q21.1 and a member of the SMAD family. Which mediates the TGF-β signaling pathway, thereby controlling the growth of epithelial cells. In the study presented here, we analyzed tumor samples by multiplex PCR-based next-generation sequencing (NGS) and found deleterious mutations of SMAD4 in 4.1% of the tumors. Knock-down experiments of endogenous and exogenous SMAD4 expression demonstrated that SMAD4 is involved in the migration and invasion of HNSCC cells. Functional analysis of a missense mutation in the MH1 domain of SMAD4 may be responsible for the loss of function in suppressing tumor progression. Missense SMAD4 mutations, therefore, could be useful prognostic determinants for patients affected by HNSCCs. This report is the first study where NGS analysis based on multiplex-PCR is used to demonstrate the imminent occurrence of missense SMAD4 mutations in HNSCC cells. The gene analysis that we performed may support the identification of SMAD4 mutations as a diagnostic marker or even as a potential therapeutic target in head and neck cancer. Moreover, the analytic strategy proposed for the detection of mutations in the SMAD4 gene may be validated as a platform to assist mutation screening.

FAT1 somatic mutations in head and neck carcinoma are associated with tumor progression and survival

In recent years, the incidence and mortality rates of head and neck squamous cell carcinoma (HNSCC) have increased worldwide. Therefore, understanding genomic alterations in HNSCC carcinogenesis is crucial for appropriate diagnosis and therapy. Protocadherin FAT1, which encodes 4588 amino acid residues, regulates complex mechanisms to promote oncogenesis or suppression of malignancies. Multiplex PCR-based next-generation sequencing (NGS) revealed FAT1 somatic mutations. The clinicopathologic implications of FAT1 in HNSCC were investigated using expression assays, and the functional role of FAT1 in HNSCC pathogenesis was determined using ectopic expression and knockdown experiments. Approximately 29% patients with HNSCC harbored damaging FAT1 mutations. InVEx algorithm identified FAT1 as a significant functional mutation burden. Each type of mutation (missense, nonsense and frameshift) accounted for nearly one-third of deleterious mutations. FAT1 mutations correlated with lower FAT1 expression in tumors. The knockdown of the endogenous expression of FAT1 and exogenous expression of crucial FAT1 domains unequivocally indicated that FAT1 suppressed the migration and invasion capability of HNSCC cells. Functional analysis suggested that nonsense mutations in FAT1 result in the loss of the suppression of tumor progression. FAT1 mutations and downregulation defined nodal involvement, lymphovascular permeation and tumor recurrence. In addition, FAT1 mutations and downregulation are independent predictors of poor disease-free survival in patients with HNSCC. This study is the first to perform multiplex PCR-based NGS to indicate marked non-synonymous FAT1 mutations in HNSCC, which are prognostic indicators. The gene analysis strategy proposed for detecting FAT1 mutations may be a valid method for mutation screening.