The MARVEL proteins CMTM4 and CMTM6 control PD-L1, thereby influencing tumor immunity. We found that defective zebrafish cmtm4 slowed the development of the posterior lateral line (pLL) by altering the Cxcr4b gradient across the pLL primordium (pLLP). Analysis in mammalian cells uncovered that CMTM4 interacted with CXCR4, altering its glycosylation pattern, but did not affect internalization or degradation of CXCR4 in the absence of its ligand CXCL12. Synchronized release of CXCR4 from the endoplasmic reticulum revealed that CMTM4 slowed CXCR4 trafficking from the endoplasmic reticulum to the plasma membrane without affecting overall cell surface expression. Altered CXCR4 trafficking reduced ligand-induced CXCR4 degradation and affected AKT but not ERK1/2 activation. CMTM4 expression, in contrast to that of CXCR4, correlated with the survival of patients with renal cell cancer in the TCGA cohort. Furthermore, we observed that cmtm4 depletion promotes the separation of cells from the pLLP cell cluster in zebrafish embryos. Collectively, our findings indicate that CMTM4 exerts general roles in the biosynthetic pathway of cell surface molecules and seems to affect CXCR4-dependent cell migration.

Here we present MARVEL, a tool for prediction of double-stranded DNA bacteriophage sequences in metagenomic bins. MARVEL uses a random forest machine learning approach. We trained the program on a dataset with 1,247 phage and 1,029 bacterial genomes, and tested it on a dataset with 335 bacterial and 177 phage genomes. We show that three simple genomic features extracted from contig sequences were sufficient to achieve a good performance in separating bacterial from phage sequences: gene density, strand shifts, and fraction of significant hits to a viral protein database. We compared the performance of MARVEL to that of VirSorter and VirFinder, two popular programs for predicting viral sequences. Our results show that all three programs have comparable specificity, but MARVEL achieves much better performance on the recall (sensitivity) measure. This means that MARVEL should be able to identify many more phage sequences in metagenomic bins than heretofore has been possible. In a simple test with real data, containing mostly bacterial sequences, MARVEL classified 58 out of 209 bins as phage genomes; other evidence suggests that 57 of these 58 bins are novel phage sequences. MARVEL is freely available at https://github.com/LaboratorioBioinformatica/MARVEL.

Anti-TNFα and anti-IL-23 antibodies are highly effective therapies for Crohn's disease or ulcerative colitis in a proportion of patients. V56B2 is a novel bispecific domain antibody in which a llama-derived IL-23p19-specific domain antibody, humanised and engineered for intestinal protease resistance, V900, was combined with a previously-described TNFα-specific domain antibody, V565. V56B2 contains a central protease-labile linker to create a single molecule for oral administration. Incubation of V56B2 with trypsin or human faecal supernatant resulted in a complete separation of the V565 and V900 monomers without loss of neutralising potency. Following oral administration of V900 and V565 in mice, high levels of each domain antibody were detected in the faeces, demonstrating stability in the intestinal milieu. In ex vivo cultures of colonic biopsies from IBD patients, treatment with V565 or V900 inhibited tissue phosphoprotein levels and with a combination of the two, inhibition was even greater. These results support further development of V56B2 as an oral therapy for IBD with improved safety and efficacy in a greater proportion of patients as well as greater convenience for patients compared with traditional monoclonal antibody therapies.

Nearly all persons newly infected with HIV-1 harbor exclusively CCR5-using virus. CXCR4-using variants eventually arise in up to 50% of patients infected with subtypes B or D. This transition to efficient CXCR4 utilization is often co-incident with progression to AIDS. The basis for HIV-1's initial dependence on CCR5, the selective force(s) that drive CXCR4-utilization, and the evolutionary pathways by which it occurs are incompletely understood. Greater knowledge of these processes will inform interventions at all stages, from vaccination to cure. The determinants of co-receptor use map primarily, though not exclusively, to the V3 loop of gp120. In this study, we describe five clonal variants with identical V3 loops but divergent CXCR4 use. Mutagenesis revealed two residues controlling this phenotypic switch: a rare polymorphism in C1 and a highly conserved N-glycan in C2. To our knowledge, this is the first description of co-receptor usage regulated by the N-glycan at position 262.

B-1 cells are an important cell population for the production of natural antibodies and front-line host defense. Here, we show that the MARVEL-domain-containing membrane protein CMTM7 (CKLF-like MARVEL transmembrane domain-containing 7) plays a critical role in BCR expression and survival in B-1a cells. We analyzed lymphocyte development in Rag1⁻/⁻ mice reconstituted with Cmtm7(flox/⁺) fetal liver cells because of the unexpected lethality of the Cmtm7(flox/⁺) heterozygotes. We found a mild reduction of serum IgM and a significantly reduced B-1a population in the peritoneal cavity of Rag1⁻/⁻ mice reconstituted with Cmtm7(flox/⁺) cells compared with those reconstituted with wild-type (WT) cells. The reduction of B-1a cells in Cmtm7(flox/⁺) mice was associated with reduced BCR expression and increased spontaneous cell death in these cells. In addition, both B-1a and B-1b cells derived from Cmtm7(flox/⁺) fetal liver cells contained a lower frequency of cells capable of spontaneously differentiating into IgM-secreting plasma cells than did those derived from WT fetal liver cells. Furthermore, Cmtm7(flox/⁺) B-1a and B-1b cells responded poorly to LPS-induced proliferation. In striking contrast to the defects in B-1 cells, Cmtm7(flox/⁺) B-2 cells did not show obvious abnormalities when compared with WT B-2 cells. These results demonstrate a specific role for CMTM7 in BCR expression and survival in B-1a cells.

Previous studies have demonstrated that the chemokine-like factor (CKLF)-like MARVEL transmembrane domain containing 8 (CMTM8) protein accelerates the ligand-induced clearance of epidermal growth factor receptor (EGFR) from the cell surface. The absence of EGFR-mediated signaling induces cells to undergo apoptosis via caspase-dependent and -independent pathways. Here we report the cloning and sequencing of an alternative splice form of CMTM8, obtained from a human blood cDNA library, that utilizes apoptotic pathways distinct from CMTM8. The alternative splice variant arises from a deletion of exon 2 that prevents the expression of a full-length MARVEL domain, and cytosolic YXXPhi motifs. Nevertheless, CMTM8-v2 maintains the ability to induce apoptosis via caspase-dependent and -independent pathways to inhibit cell growth and colony formation. CMTM8 and CMTM8-v2 display different expression profiles and distinct subcellular localization patterns, while operating via different mechanisms to induce apoptosis. CMTM8-v2 did not affect EGFR internalization, implying that the MARVEL domain and/or the cytosolic YXXPhi motifs are necessary for CMTM8 to accelerate ligand-induced EGFR internalization.

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family involved in multiple malignancies. CMTM4 is a member of this family and is located at chromosome 16q22.1, a locus that harbours a number of tumour suppressor genes. It has been defined as a regulator of cell cycle and division in HeLa cells; however, its roles in tumourigenesis remain poorly studied.

Breast cancer is the major cause of death in females globally. Chemokine-like factor like MARVEL transmembrane domain containing 7 (CMTM7) is reported as a tumor suppressor and is involved in epidermal growth factor receptor degradation and PI3K/AKT signaling in previous studies. However, other molecular mechanisms of CMTM7 remain unclear.

Membrane organization into condensed domains or rafts provides molecular platforms for selective recruitment of proteins. Cell migration is a general process that requires spatiotemporal targeting of Rac1 to membrane rafts. The protein machinery responsible for making rafts competent to recruit Rac1 remains elusive. Some members of the MAL family of proteins are involved in specialized processes dependent on this type of membrane. Because condensed membrane domains are a general feature of the plasma membrane of all mammalian cells, we hypothesized that MAL family members with ubiquitous expression and plasma membrane distribution could be involved in the organization of membranes for cell migration. We show that myeloid-associated differentiation marker (MYADM), a protein with unique features within the MAL family, colocalizes with Rac1 in membrane protrusions at the cell surface and distributes in condensed membranes. MYADM knockdown (KD) cells had altered membrane condensation and showed deficient incorporation of Rac1 to membrane raft fractions and, similar to Rac1 KD cells, exhibited reduced cell spreading and migration. Results of rescue-of-function experiments by expression of MYADM or active Rac1L61 in cells knocked down for Rac1 or MYADM, respectively, are consistent with the idea that MYADM and Rac1 act on parallel pathways that lead to similar functional outcomes.

Anomalous epidermal growth factor receptor (EGFR) signaling plays an important role in the progression of prostate cancer (PCa) and the transformation to castration-resistant PCa (CRPC). A novel tumor suppressor CKLF-like MARVEL transmembrane domain-containing member 5(CMTM5) has a MARVEL domain and may regulate transmembrane signaling. Thus, we postulated that CMTM5 could regulate EGFR and its downstream molecules to affect the biological behaviors of PCa cells. In this study, we found that CMTM5 was expressed in benign prostatic hyperplasia (BPH) tissues but was undetectable in PCa cells. However, the EGFR was upregulated in PCa cells, especially in two metastatic CRPC cell lines, PC3 and DU145. Furthermore, ectopic expression of CMTM5-v1 suppressed cell proliferation and migration and p-EGFR levels. Further investigation revealed that restoration of CMTM5-v1 inhibited not only EGF-mediated proliferation but also chemotactic migration by EGF in PC3 and DU145 cells. Moreover, mechanistic studies showed that CMTM5-v1 attenuated EGF-induced receptor signaling by repressing EGFR and Akt phosphorylation in PCa cells, which were essential for malignant features. Finally, CMTM5-v1can promote the sensitivity of PC3 cells to Gefetinib, a tyrosine kinase inhibitor (TKI) targeting the EGFR. These observations indicate that CMTM5-v1 suppressed PCa cells through EGFR signaling. The loss of CMTM5 may participate in the progression of PCa resulting from deregulated EGFR, and CMTM5 might be associated with the efficacy of TKIs in terms of their potent inhibition of EGFR and human epidermal growth factor-2 (HER2) activation.

CKLF-like MARVEL transmembrane domain-containing 5 (CMTM5) has been reported to function as a potential tumor suppressor in several human cancers. However, the involvement of CMTM5 in human renal cell carcinoma (RCC) remains unclear. The current study aimed to detect its expression pattern in RCC tissues and cells, and to determine its anti-proliferative functions in this malignancy. The mRNA and protein expression levels of CMTM5 in RCC tissues and cells were detected by reverse transcription-quantitative polymerase chain reaction, immunohistochemistry and western blotting. Following the transfection with CMTM5 lentivirus or control lenti-EGFP lentivirus into the RCC cell line ACHN, the viability, migration, apoptosis and cell cycle of these cells were detected by Cell Counting kit-8 assay, Transwell assay and flow cytometry, respectively. Compared with the adjacent non-malignant kidney tissue samples, CMTM5 expression was significantly downregulated in RCC tissues (P<0.05). In addition, enforced expression of CMTM5 could efficiently inhibit the cell growth of ACHN cells, which were arrested in G0/G1 phase. Furthermore, the migration and invasion of ACHN cells were also inhibited by restoration of CMTM5 expression. The present data suggest that CMTM5 may function as a tumor suppressor in human RCC by suppressing the viability of RCC cells, implying its potential as a therapeutic target for this malignancy.

Cell adhesion on an extracellular matrix (ECM) participates in cell motility, invasion, cell signal transduction and gene expression. Many nuclear proteins regulate cell-ECM adhesion through managing the transcription of cell adhesion-related genes. Here, we identified MARVEL [MAL (The myelin and lymphocyte protein) and related proteins for vesicle trafficking and membrane link] domain containing 1 (MARVELD1) that could suppress cell spreading and complicate actin organization. Over-expression of MARVELD1 in NIH3T3 cells decreased the expression level of integrin β1 and vinculin, and further led to dephosphorylation of focal adhesion kinase (FAK) at Tyr 397. We also found that MARVELD1 partially colocalized with serine/arginine-rich splicing factor 2 (SC35) and interacted with nuclear cap binding protein subunit 2 (CBP20). Finally, we demonstrated that pre-mRNA processing of integrin β1 was affected by MARVELD1. Taken together, our studies demonstrate that MARVELD1 plays a role in pre-mRNA processing of integrin β1, and thereby regulates cell adhesion and cell motility. These studies provide a novel regulatory mechanism of cell-ECM adhesion by nuclear protein in cells.

Bladder cancer is the most common tumor of the urinary tract. The incidence of bladder cancer has increased in the last few decades, thus novel molecular markers for early diagnosis and more efficacious treatment are urgently needed. Chemokine‑like factor (CKLF)‑like MARVEL transmembrane domain containing 8 (CMTM8) is downregulated in several types of cancers and is associated with tumor progression. However, CMTM8 expression has been unexplored in bladder cancer to date. Our results revealed that the expression of CMTM8 was negative in 46 of 74 (62.2%) bladder cancer samples via immunohistochemistry assay. CMTM8 downregulation was associated with advancing tumor stage and tumor grade. CMTM8 was successfully overexpressed by lentivirus in EJ and T24 cells, and the CCK‑8 and Transwell assays showed that CMTM8 overexpression decreased cell proliferation, migration and invasion in vitro. In tumor xenografts upregulation of CMTM8 inhibited tumor growth and lymph node metastasis in vivo. In conclusion, overexpression of CMTM8 in bladder cancer results in reduced malignant cell growth, migration and invasion, which could make it a potential therapeutic target in the treatment of bladder cancer.

The CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) gene is a novel tumor suppressor with frequent epigenetic inactivation. In this study, we showed the role played by CMTM3 in gastric cancer cells as a tumor suppressor gene, and examined the correlation between CMTM3 expression and clinicopathological parameters using immunohistochemistry in gastric cancer patients with different pathological stages (n = 350). We found that CMTM3 expression was reduced or silenced by epigenetic regulation in gastric cell lines, and dramatically downregulated in primary gastric cancer tissues. Restoration of CMTM3 significantly affected migration and invasion of AGS and SGC-7901 cells (P < 0.001). In vivo experiments showed that peritoneal disseminated metastases were significantly suppressed by CMTM3 (P < 0.001). We further showed that the expression of MMP2 and the phosphorylation of Erk1/2 were decreased when CMTM3 was restored. In addition, by immunohistochemical staining, we found that the expression of CMTM3 was remarkably weaker in gastric cancer tissues than in normal mucosae (P = 0.008), and was significantly correlated with gender (P = 0.033), tumor depth (P = 0.049), stage (P = 0.021), and histological grade (P = 0.022). More importantly, CMTM3 expression was associated with prognosis in gastric cancer patients (P = 0.041), and was a significant independent prognostic indicator (hazard ratio = 0.704, 95% confidence interval, 0.498-0.994; P = 0.046). Our findings indicate that CMTM3 regulates migration and invasion of gastric cancer cells. Moreover, CMTM3 is a candidate marker for prognosis of gastric cancer in the clinic.

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer is characterized by invasive growth, rapid metastasis and chemoresistance. Trastuzumab is an effective treatment for HER2+ breast cancer; however, trastuzumab resistance leads to cancer relapse and metastasis. CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) has been considered as a new immune checkpoint for tumor-induced immunosuppression. The role of CMTM6 in trastuzumab resistance remains unknown. Here, we uncover a role of CMTM6 in trastuzumab-resistant HER2+ breast cancer. CMTM6 expression was upregulated in trastuzumab-resistant HER2+ breast cancer cell. Patients with high CMTM6 expressing HER2+ breast cancer had worse overall and progression-free survival than those with low CMTM6 expression. In vitro, CMTM6 knockdown inhibited the proliferation and migration of HER2+ breast cancer cells, and promoted their apoptosis, while CMTM6 overexpression reversed these effects. CMTM6 and HER2 proteins were co-localized on the surface of breast cancer cells, and CMTM6 silencing reduced HER2 protein levels in breast cancer cells. Co-immunoprecipitation revealed that CMTM6 directly interacted with HER2 in HER2+ breast cancer cells, and CMTM6 overexpression inhibited HER2 ubiquitination. Collectively, these findings highlight that CMTM6 stabilizes HER2 protein, contributing to trastuzumab resistance and implicate CMTM6 as a potential prognostic marker and therapeutic target for overcoming trastuzumab resistance in HER2+ breast cancer.

CKLF-like MARVEL transmembrane domain-containing protein 6 (CMTM6) is known to be a regulator of membranal programmed death ligand 1 (PD-L1) stability and a factor associated with malignancy progression, but the effects and mechanisms of CMTM6 on tumor growth, as well as its potential as a target for therapy, are still largely unknown. Here, we show that CMTM6 expression increased with tumor progression in both patients and mice. Ablation of CMTM6 significantly reduced human and murine tumor growth in a manner dependent on T-cell immunity. Tumor CMTM6 suppression broke resistance to immune-checkpoint inhibitors and remodeled the tumor immune microenvironment, as specific antitumor cytotoxicity was enhanced and contributed primarily to tumor inhibition. Without the PD-1/PD-L1 axis, CMTM6 suppression still significantly dampened tumor growth dependent on cytotoxic cells. Furthermore, we identified that CMTM6 was widely expressed on immune cells. T-cell CMTM6 levels increased with sustained immune activation and intratumoral immune exhaustion and affected T cell-intrinsic PD-L1 levels. Host CMTM6 knockout significantly restrained tumor growth in a manner dependent on CD8+ T cells and not entirely dependent on PD-L1. Thus, we developed and evaluated the antitumor efficacy of CMTM6-targeting adeno-associated virus (AAV), which effectively mobilized antitumor immunity and could be combined with various antitumor drugs. Our findings reveal that both tumor and host CMTM6 are involved in antitumor immunity with or without the PD-1/PD-L1 axis and that gene therapy targeting CMTM6 is a promising strategy for cancer immunotherapy.

Early detection of oral squamous cell carcinomas (OSCCs) is urgently needed to improve the prognosis and quality of life (QOL) of patients. Oral leukoplakias (OLs), known as the most common premalignant lesions in the oral cavity, often precede OSCCs. Especially, OLs with dysplasia are known to have a high risk of malignant transformation. Here, we searched for the promoter methylation characteristic of high-risk OLs.

Background: Recent evidence has shown that CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) promoted carcinogenesis and tumor progression in a variety of cancer types. The goal of our study is to investigate the association between CMTM3 and pancreatic cancer (PC). Materials and Methods: In current study, data from public databases was used to analyze CMTM3 expression in PC. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) were used to investigate CMTM3 expression and determine its clinical significance in PC. Then CMTM3 promoting PC aggressiveness was demonstrated in vitro experiments by cell proliferation and migration assay. Functional and pathway enrichment analyses were performed to evaluate the potential role of CMTM3 in PC. Results: Results of qRT-PCR and IHC revealed that CMTM3 was significantly overexpressed in PC tissues. High CMTM3 expression was an independent risk factor for poor prognosis of PC patients. Overexpression of CMTM3 was associated with poor overall survival (P-value =0.031) and disease-free survival (P-value =0.0047) in the TCGA cohort. Functional and pathway enrichment analyses showed that CMTM3 were enriched in "Regulation of cell proliferation and regulation of cell differentiation, cell morphogenesis, regulation of cell differentiation, Hedgehog signaling pathway, Wnt signaling pathway, ECM-receptor interaction and pathways in cancer". In PC cell lines, CCK8, clone formation and transwell assays showed that CMTM3 knockdown inhibited cells proliferation and migration. Conclusion: CMTM3 was overexpressed and promotes tumor aggressiveness in PC. Our findings provided a novel therapeutic target for PC.

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain containing 6 (CMTM6) modulates degradation of a number of proteins, including programmed death ligand-1 (PD-L1) by protecting it from ubiquitin-mediated degradation. In this role, it could modulate the effectiveness of immunotherapy. Here, for the first time, we characterize CMTM6 expression in melanoma and evaluate its association with response to immune checkpoint inhibitors (ICI). We evaluated the expression of CMTM6, PD-L1 and other immune-related proteins in 60 pretreatment biopsies from metastatic melanoma patients who received immunotherapy, in a tissue microarray (TMA) using quantitative immunofluorescence (QIF). Expression of mRNA from control patients obtained from The Cancer Genome Atlas (TCGA) database was also compared. CMTM6 expression was positively correlated with PD-L1, CD3, CD20, and CD68 markers, at protein (Pearson's r = 0.53-0.81, all P < .0001) and mRNA (Spearman's r = 0.15-0.44, all P < .002, except for CD68 where P = .26) levels. CMTM6 protein was associated with longer survival after immunotherapy when measured in the stromal (P = .007) and all the immune compartments tested (T cells, B cells, and macrophages). Multivariable analyses also revealed significant CMTM6 survival associations when measured in stromal (Hazard Ratio (HR) = 0.12, P = .001) and CD68-positive (HR = 0.30, P = .043) compartments. Additionally, PD-L1 but not CMTM6 showed prognostic value in control patients. Finally, high CMTM6 and PD-L1 co-expression in the stromal compartment was significantly associated with longer survival in treated patients (P = .028). Consequently, CMTM6 expression shows potential as a predictive factor for ICI treatments.

CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) was identified as a regulator of programmed death ligand 1 (PD-L1), which induces antitumor immunity in several cancers. This study aimed to clarify the relationship between CMTM6 and PD-L1 expression and clinical outcomes in patients with hepatocellular carcinoma (HCC). In total, 259 patients with HCC who had undergone hepatic resection were enrolled. Immunohistochemical staining for CMTM6 and PD-L1 was performed. The relationships between CMTM6 expression and the clinicopathological characteristics and outcomes were analyzed. Additionally, the stabilization of PD-L1 expression and regulation of malignant activities by CMTM6 were examined in vitro. Our patients were divided into high (n = 65, 25.1%) and low (n = 194, 74.9%) CMTM6 expression groups. High CMTM6 expression was significantly associated with malignant aggregates, including poor differentiation (P < 0.0001), microscopic intrahepatic metastasis (P = 0.0369), and multiple intrahepatic recurrences (P = 0.0211). CMTM6 expression was significantly correlated with PD-L1 expression in HCC tissues (P < 0.0001). The patients were classified into three groups: high CMTM6/PD-L1 positive (n = 21), high CMTM6/ PD-L1 negative (n = 44), and low CMTM6 (n = 194) expression pattern groups. Overall survival was significantly different among the three groups (P < 0.0001). Additionally, immunohistochemical double staining revealed that CMTM6 and PD-L1 were co-expressed on HCC cells. In vitro, PD-L1 expression was enhanced at late time points in the presence of CMTM6 expression. CMTM6 also regulated epithelial-to-mesenchymal transition and stemness phenotypes in HCC cells. Conclusion: Our large cohort study found that CMTM6 co-expressed with PD-L1 was strongly associated with the clinical outcome in patients with HCC. The evaluation of CMTM6 combined with PD-L1 in HCC might be useful for patient selection in immune checkpoint therapy.