FAT1 inhibits cell migration and invasion by affecting cellular mechanical properties in esophageal squamous cell carcinoma

Recent advances in the role of atypical cadherin FAT1 in tumorigenesis (Review)

The FAT atypical cadherin 1 (FAT1) gene is the ortholog of the Drosophila fat gene and encodes the protocadherin FAT1. FAT1 belongs to the cadherin superfamily, a group of full-length membrane proteins that contain cadherin-like repeats. In various types of human cancer, FAT1 is one of the most commonly mutated genes, and is considered to be an emerging cancer biomarker and a potential target for novel therapies. However, the biological functions of FAT1 and the precise downstream signaling pathways that it mediates have remained to be fully elucidated. The present review discussed the current literature on FAT1, focusing on FAT1 mutations and expression levels, and their impact on signaling pathways and mechanisms in various types of cancer, including both solid tumors and hematological malignancies, such as esophageal squamous cell carcinoma, head and neck squamous cell carcinoma, lung squamous cell carcinoma, hepatocellular carcinoma, glioma, breast cancer, acute lymphoblastic leukemia, acute myeloid leukemia, lymphoma and myeloma. The present review aimed to provide further insights and research directions for future studies on FAT1 as an oncogenic factor or tumor suppressor.

Somatic mutations in FAT cadherin family members constitute an underrecognized subtype of colorectal adenocarcinoma with unique clinicopathologic features

BACKGROUND

The FAT cadherin family members (FAT1, FAT2, FAT3 and FAT4) are conserved tumor suppressors that are recurrently mutated in several types of human cancers, including colorectal carcinoma (CRC).

AIM

To characterize the clinicopathologic features of CRC patients with somatic mutations in FAT cadherin family members.

METHODS

We analyzed 526 CRC cases from The Cancer Genome Atlas PanCancer Atlas dataset. CRC samples were subclassified into 2 groups based on the presence or absence of somatic mutations in FAT1, FAT2, FAT3 and FAT4. Individual clinicopathological data were collected after digital slide review. Statistical analysis was performed using t tests and chi-square tests.

RESULTS

This CRC study cohort had frequent mutations in the FAT1 (10.5%), FAT2 (11.2%), FAT3 (15.4%) and FAT4 (23.4%) genes. Two hundred CRC patients (38.0%) harbored somatic mutations in one or more of the FAT family genes and were grouped into the FAT mutated CRC subtype. The FAT-mutated CRC subtype was more commonly located on the right side of the colon (51.0%) than in the rest of the cohort (30.1%, P < 0.001). It showed favorable clinicopathologic features, including a lower rate of positive lymph nodes (pN1-2: 33.5% vs 46.4%, P = 0.005), a lower rate of metastasis to another site or organ (pM1: 7.5% vs 16.3%, P = 0.006), and a trend toward an early tumor stage (pT1-2: 25.0% vs 18.7%, P = 0.093). FAT somatic mutations were significantly enriched in microsatellite instability CRC (28.0% vs 2.1%, P < 0.001). However, FAT somatic mutations in microsatellite stable CRC demonstrated similar clinicopathologic behaviors, as well as a trend of a better disease-free survival rate (hazard ratio = 0.539; 95% confidence interval: 0.301-0.967; log-rank P = 0.073).

CONCLUSION

FAT cadherin family genes are frequently mutated in CRC, and their mutation profile defines a subtype of CRC with favorable clinicopathologic characteristics.

FAT1 downregulation enhances stemness and cisplatin resistance in esophageal squamous cell carcinoma

Primary or acquired drug resistance accounts for the failure of chemotherapy and cancer recurrence in esophageal squamous cell carcinoma (ESCC). However, the aberrant mechanisms driving drug resistance are not fully understood in ESCC. In our previous study, FAT Atypical Cadherin 1 (FAT1) was found to inhibit the epithelial-mesenchymal transition (EMT) process in ESCC. EMT plays a critical role in the development of drug resistance in multiple cancer types. Besides, it equips cancer cells with cancer stem cell (CSC)-like characters that also are associated with chemotherapy resistance. Whether FAT1 regulates the stemness or drug resistance of ESCC cells is worth being explored. Here we found that FAT1 was downregulated in ESCC spheres and negatively correlated with stemness-associated markers including ALDH1A1 and KLF4. Knocking down FAT1 enhanced the sphere-forming ability, resistance to cisplatin and drug efflux of ESCC cells. Additionally, FAT1 knockdown upregulated the expression of drug resistance-related gene ABCC3. Furtherly, we found FAT1 knockdown induced the translocation of β-catenin into nucleus and enhanced its transcriptional activity. The result of ChIP showed that β-catenin was enriched in ABCC3 promoter. Furthermore, β-catenin promoted expression of ABCC3. In conclusion, FAT1 knockdown might enhance the stemness and ABCC3-related cisplatin resistance of ESCC cells via Wnt/β-catenin signaling pathway. FAT1 and its downstream gene ABCC3 might be potential targets for overcoming chemoresistance in ESCC.

FAT1 and PTPN14 Regulate the Malignant Progression and Chemotherapy Resistance of Esophageal Cancer through the Hippo Signaling Pathway

Background

Esophageal cancer (EC) is a common malignant tumor, which brings heavy economic burden to patients and society. Therefore, it is important to understand the molecular mechanism of recurrence, metastasis, and drug resistance of esophageal cancer.

Methods

Human esophageal cancer cell line TE13 (poorly differentiated squamous cell carcinoma) and normal human esophageal epithelial cell line het-1a were selected for aseptic culture. At the same time, 6 bottles of TE13 cell line were inoculated in logarithmic phase. Cell apoptosis was analyzed by flow cytometry (FCM). Cell clone formation assay was used to analyze the proliferation. Fibronectin-coated dishes were used to detect the characteristics of cell adhesion to extracellular matrix. The Transwell method was used to detect the cell invasion ability. Western blot was used to analyze the expression of Yap1, PTPN14, FAT1, and Myc.

Results

Results showed that FAT1 and PTPN14 were downregulated, while Yap1 was upregulated in esophageal cancer tissues. FAT1 inhibited the proliferation, adhesion, and invasion of human esophageal cancer cell lines, which might be associated with the upregulation of PTPN14 and the inhibition of Yap1 and Myc.

Conclusion

The results suggested that PTPN14 and FAT1 could regulate malignant progression and chemotherapy resistance of esophageal cancer based on the Hippo signaling pathway.

Molecular Changes in Retinoblastoma beyond RB1: Findings from Next-Generation Sequencing

Simple Summary

The gene causing retinoblastoma was the first tumor suppressor cloned (1986) and because retinoblastoma is the classic example of autosomal dominant inheritance, there has been little research on non-RB1 alterations in tumors and the impact these alterations have on growth patterns in the eye, metastases and predilection for non-ocular cancers. This study interrogated enucleated retinoblastoma specimens using a MSK-IMPACT clinical next-generation sequencing panel with the aim to correlate them with clinicopathologic characteristics. We found that vitreous seeding (the main reason for eye removal) correlates with copy number variations, specifically 1q gains and 16q loss. We also found that somatic BCOR mutations correlate with propensity for metastasis and this offers a molecular pathway for monitoring high risk tumors. In addition, the finding that 11% of these retinoblastoma patients have additional germline mutations (on other chromosomes) that predispose them to a different host of cancers throughout their lives enables more targeted and specific screening strategies.

Abstract

This investigation uses hybridization capture-based next-generation sequencing to deepen our understanding of genetics that underlie retinoblastoma. Eighty-three enucleated retinoblastoma specimens were evaluated using a MSK-IMPACT clinical next-generation sequencing panel to evaluate both somatic and germline alterations. Somatic copy number variations (CNVs) were also identified. Genetic profiles were correlated to clinicopathologic characteristics. RB1 inactivation was found in 79 (97.5%) patients. All specimens had additional molecular alterations. The most common non-RB1 gene alteration was BCOR in 19 (22.9%). Five (11.0%) had pathogenic germline mutations in other non-RB1 cancer predisposition genes. Significant clinicopathologic correlations included: vitreous seeds associated with 1q gains and 16q loss of heterozygosity (BH-corrected p-value = 0.008, 0.004; OR = 12.6, 26.7, respectively). BCOR mutations were associated with poor prognosis, specifically metastases-free survival (MFS) (nominal p-value 0.03). Furthermore, retinoblastoma patients can have non-RB1 germline mutations in other cancer-associated genes. No two specimens had the identical genetic profile, emphasizing the individuality of tumors with the same clinical diagnosis.

Sulforaphane suppresses the viability and metastasis, and promotes the apoptosis of bladder cancer cells by inhibiting the expression of FAT‑1

FAT atypical cadherin 1 (FAT1) regulates complex mechanisms for the promotion of oncogenesis or the suppression of malignancies. Sulforaphane (SFN) has antioxidant and anti-tumor activities. The present study investigated the roles of SFN and FAT1 in bladder cancer (BC). The expression of FAT1 in BC cell lines and tissues was measured by western blot analysis and reverse transcription-quantitative PCR (RT-qPCR). The association between FAT1 expression and the 5-year survival rate of patients with BC was evaluated. The viability of and FAT1 expression in T24 and SW780 cells exposed to various concentrations of SFN were detected by MTT assay, and western blot analysis and RT-qPCR, respectively. Furthermore, the viability, migration, invasion and apoptosis of and FAT1 expression in BC cells subjected to FAT1 overexpression or knockdown, and with or without SFN stimulation, were examined. The results revealed that FAT1 expression in BC cells and tissues was increased, and patients with a high FAT-1 expression had a shorter 5-year survival time than those with a low FAT-1 expression. BC cell viability and FAT1 expression were suppressed by SFN in a concentration-dependent manner. The knockdown of FAT1 inhibited the viability, migration and invasion, and promoted the apoptosis of BC cells, whereas the overexpression of FAT1 produced opposite effects. In addition, cells exposed to SFN exhibited a reduced viability, migration, invasion and an increased apoptosis, effects which were promoted by FAT1 knockdown; however, the overexpression of FAT1 blocked the above-mentioned effects of SFN on the cells. On the whole, the present study demonstrates that SFN suppresses the progression of BC by inhibiting the expression of FAT-1; thus, SFN may be used as a potential drug for the treatment of BC.

Heterogeneous genomic aberrations in esophageal squamous cell carcinoma: a review

Esophageal cancer (EC) causes hundreds of thousands of deaths a year worldwide, especially the major subtype esophageal squamous cell carcinoma (ESCC). With the advent of next-generation sequencing and the availability of commercial microarrays, abnormities in genetic levels have been revealed in various independent researches. High frequencies of structure variations (SVs), single nucleotide variations (SNVs) and copy-number alterations (CNAs) in ESCCs are uncovered, and ESCC shows high levels of inter- and intratumor heterogeneity, implying diverse evolutionary trajectories. This review tries to explain the pathogenesis of ESCC on the scope of most often mutated genes based on prior studies, hopes to offer some hints for diagnosis and therapy in clinic.

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

The mechanical properties of cells could serve as an indicator for disease progression and early cancer diagnosis. This study utilized atomic force microscopy (AFM) to measure the viscoelastic properties of ovarian cancer cells and then examined the association with the invasion of ovarian cancer at the level of living single cells. Elasticity and viscosity of the ovarian cancer cells OVCAR-3 and HO-8910 are significantly lower than those of the human ovarian surface epithelial cell (HOSEpiC) control. Further examination found a dramatic increase of migration/invasion and an obvious decease of microfilament density in OVCAR-3 and HO-8910 cells. Also, there was a significant relationship between viscoelastic and biological properties among these cells. In addition, the elasticity was significantly increased in OVCAR-3 and HO-8910 cells after the treatment with the anticancer compound echinomycin (Ech), while no obvious change was found in HOSEpiC cells after Ech treatment. Interestingly, Ech seemed to have no effect on the viscosity of the cells. Ech significantly inhibited the migration/invasion and significantly increased the microfilament density in OVCAR-3 and HO-8910 cells, which was significantly related with the elasticity of the cells. An increase of elasticity and a decrease of invasion were found in OVCAR-3 and HO-8910 cells after Ech treatment. Together, this study clearly demonstrated the association of viscoelastic properties with the invasion of ovarian cancer cells and shed a light on the biomechanical changes for early diagnosis of tumor transformation and progression at single-cell level.

miR-302a Inhibits Metastasis and Cetuximab Resistance in Colorectal Cancer by Targeting NFIB and CD44

Introduction: Metastasis and drug resistance contribute substantially to the poor prognosis of colorectal cancer (CRC) patients. However, the epigenetic regulatory mechanisms by which CRC develops metastatic and drug-resistant characteristics remain unclear. This study aimed to investigate the role of miR-302a in the metastasis and molecular-targeted drug resistance of CRC and elucidate the underlying molecular mechanisms.

Methods: miR-302a expression in CRC cell lines and patient tissue microarrays was analyzed by qPCR and fluorescence in situ hybridization. The roles of miR-302a in metastasis and cetuximab (CTX) resistance were evaluated both in vitro and in vivo. Bioinformatic prediction algorithms and luciferase reporter assays were performed to identify the miR-302a binding regions in the NFIB and CD44 3'-UTRs. A chromatin immunoprecipitation assay was performed to examine NFIB occupancy in the ITGA6 promoter region. Immunoblotting was performed to identify the EGFR-mediated pathways altered by miR-302a.

Results: miR-302a expression was frequently reduced in CRC cells and tissues, especially in CTX-resistant cells and patient-derived xenografts. The decreased miR-302a levels correlated with poor overall CRC patient survival. miR-302a overexpression inhibited metastasis and restored CTX responsiveness in CRC cells, whereas miR-302a silencing exerted the opposite effects. NFIB and CD44 were identified as novel targets of miR-302a. miR-302a inhibited the metastasis-promoting effect of NFIB that physiologically activates ITGA6 transcription. miR-302a restored CTX responsiveness by suppressing CD44-induced cancer stem cell-like properties and EGFR-mediated MAPK and AKT signaling. These results are consistent with clinical observations indicating that miR-302a expression is inversely correlated with the expression of its targets in CRC specimens.

Conclusions: Our findings show that miR-302a acts as a multifaceted regulator of CRC metastasis and CTX resistance by targeting NFIB and CD44, respectively. Our study implicates miR-302a as a candidate prognostic predictor and a therapeutic agent in CRC.

FAT1 inhibits the proliferation and metastasis of cervical cancer cells by binding β-catenin

FAT1 is a mutant gene found frequently in human cervical cancer (CC), but its expression and relevance in CC proliferation, invasion, and migration are still unknown. We aimed to explore the role and novel mechanism of FAT1 in CC progression. The expression of FAT1 in CC and adjacent normal tissues was analysed, and we investigated the proliferation, migration, and invasion of HeLa and C33A cells treated with wild-type FAT1 plasmid or FAT1 siRNA. Meanwhile, we evaluated the effect of FAT1 on the epithelial-mesenchymal transition (EMT) and the β-catenin-mediated transcription of target genes. Here, we showed that FAT1 expression was significantly lower in CC tissues than in adjacent tissues. FAT1 overexpression significantly dysregulated CC cell proliferation, invasion, and migration, whereas FAT1 knockdown had the opposite effect. FAT1 overexpression promoted the expression of phosphorylated β-catenin and E-cadherin protein and inhibited the expression of vimentin, TWIST, and several downstream targets of β-catenin, namely, c-MYC, TCF-4 and MMP14. In contrast, FAT1 silencing notably increased the expression c-MYC, TCF-4, and MMP14 and promoted the EMT in HeLa and C33A cells. Endogenous and exogenous FAT1 was confirmed to interact with β-catenin, and the overexpression of β-catenin could partially block the effect of FAT1 on the proliferation, migration, and invasion of HeLa and C33A cells. Conclusion: FAT1 acts as a tumor suppressor by inhibiting β-catenin-mediated transcription and might be used as a novel anti-metastatic agent in targeted CC therapy.

Discoidin domain receptor 1 deficiency in vascular smooth muscle cells leads to mislocalisation of N-cadherin contacts

N-cadherin mediates cell–cell contacts in vascular smooth muscle cells (VSMCs), and regulates VSMC behaviours including migration and proliferation. Discoidin domain receptor 1 (DDR1) is a collagen binding receptor also implicated in these processes. Previous studies have shown that both N-cadherin and DDR1 are upregulated after vascular injury, but it is not known whether there is a relationship between the two molecules. In the current study we found that N-cadherin was mislocalised from cell–cell junctions in the absence of DDR1. This occurred in spite of the fact that there was no significant difference in total cell lysate levels of N-cadherin between DDR1+/+ and DDR1−/− VSMCs. Analysis of lipid raft fractions revealed decreased N-cadherin and associated junctional complex catenins in DDR1−/− compared to DDR1+/+ VSMCs. Treatment with cholesterol oxidase or methyl-β-cyclodextrin to disrupt lipid rafts removed N-cadherin and DDR1 from the raft fractions. Reciprocal co-immunoprecipitations suggested the association of DDR1 and N-cadherin. Importantly, transfection of DDR1−/− cells with full-length DDR1b rescued the formation of N-cadherin junctions. Together, these data reveal that N-cadherin cell–cell contacts in VSMCs are regulated through interactions with DDR1 and both molecules are located in lipid rafts.

Summary: Here we show for the first time that discoidin domain receptor 1 associates with and stabilizes N-cadherin cell–cell contacts in vascular smooth muscle cells.

Transcriptomic analysis to affirm the regulatory role of long non-coding RNA in horn cancer of Indian zebu cattle breed Kankrej (Bos indicus)

Long non-coding RNA (lncRNA) was previously considered as a non-functional transcript, which now established as part of regulatory elements of biological events such as chromosome structure, remodeling, and regulation of gene expression. The study presented here showed the role of lncRNA through differential expression analysis on cancer-related coding genes in horn squamous cell carcinoma of Indian zebu cattle. A total of 10,360 candidate lncRNAs were identified and further analyzed for its coding potential ability using three tools (CPC, CPAT, and PLEK) that provide 8862 common lncRNAs. Pfam analysis of these common lncRNAs gave 8612 potential candidates for lncRNA differential expression analysis. Differential expression analysis showed a total of 59 significantly differentially expressed genes and 19 lncRNAs. Pearson's correlation analysis was used to identify co-expressed mRNA-lncRNAs to established relation of the regulatory role of lncRNAs in horn cancer. We established a positive relation of seven upregulated (XLOC_000016, XLOC_002198, XLOC_002851, XLOC_ 007383, XLOC_010701, XLOC_010272, and XLOC_011517) and one downregulated (XLOC_011302) lncRNAs with eleven genes that are related to keratin family protein, keratin-associated protein family, cornifelin, corneodesmosin, serpin family protein, and metallothionein that have well-established role in squamous cell carcinoma through cellular communication, cell growth, cell invasion, and cell migration. These biological events were found to be related to the MAPK pathway of cell cycle regulation indicating the role of lncRNAs in manipulating cell cycle regulation during horn squamous cell carcinomas that will be useful in identifying molecular portraits related to the development of horn cancer.

High individual variability in the transcriptomic response of Mediterranean mussels to Vibrio reveals the involvement of myticins in tissue injury

Mediterranean mussels (Mytilus galloprovincialis) are sessile filter feeders that live in close contact with numerous marine microorganisms. As all invertebrates, they lack an adaptive immune response and how these animals are able to respond to a bacterial infection and discriminate it from their normal microbiome is difficult to understand. In this work, we conducted Illumina sequencing of the transcriptome of individual mussels before and after being infected with Vibrio splendidus. The control mussels were injected with filtered seawater. We demonstrate that a great variability exists among individual transcriptomes and that each animal showed an exclusive repertoire of genes not shared with other individuals. The regulated genes in both the control and infected mussels were also analyzed and, unexpectedly, the sampling before the injection was considered a stress stimulus strong enough to trigger and modulate the response in hemocytes, promoting cell migration and proliferation. We found a clear response against the injection of filtered seawater, suggesting a reaction against a tissue injury in which the myticins, the most expressed antimicrobial peptides in mussel, appeared significantly up regulated. Functional experiments with flow cytometry confirmed the transcriptomic results since a significant alteration of hemocyte structures and a decrease in the number of hemocytes positive for myticin C were found only after a Vibrio infection and not observed when mussels were bled before, generating a tissue injury. Therefore, we report the involvement of myticins in the response to a danger signal such as a simple injection in the adductor muscle.

FAT1, a direct transcriptional target of E2F1, suppresses cell proliferation, migration and invasion in esophageal squamous cell carcinoma

Objective

Growing evidence indicates that FAT atypical cadherin 1 (FAT1) has aberrant genetic alterations and exhibits potential tumor suppressive function in esophageal squamous cell carcinoma (ESCC). However, the role of FAT1 in ESCC tumorigenesis remains not well elucidated. The aim of this study was to further investigate genetic alterations and biological functions of FAT1, as well as to explore its transcriptional regulation and downstream targets in ESCC.

Methods

The mutations of FAT1 in ESCC were achieved by analyzing a combined study from seven published genomic data, while the copy number variants of FAT1 were obtained from an analysis of our previous data as well as of The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) databases using the cBioPortal. The transcriptional regulation of FAT1 expression was investigated by chromatin immunoprecipitation (ChIP) and the luciferase reporter assays. In-cell western, Western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to assess the indicated gene expression. In addition, colony formation and Transwell migration/invasion assays were employed to test cell proliferation, migration and invasion. Finally, RNA sequencing was used to study the transcriptomes.

Results

FAT1 was frequently mutated in ESCC and was deleted in multiple cancers. Furthermore, the transcription factor E2F1 occupied the promoter region of FAT1, and depletion of E2F1 led to a decrease in transcription activity and mRNA levels of FAT1. Moreover, we found that knockdown of FAT1 promoted KYSE30 and KYSE150 cell proliferation, migration and invasion; while overexpression of FAT1 inhibited KYSE30 and KYSE410 cell proliferation, migration and invasion. In addition, knockdown of FAT1 led to enrichment of the mitogen-activated protein kinase (MAPK) signaling pathway and cell adhesion process.

Conclusions

Our data provided evidence for the tumor suppressive function of FAT1 in ESCC cells and elucidated the transcriptional regulation of FAT1 by E2F1, which may facilitate the understanding of molecular mechanisms of the progression of ESCC.