CMTM3 decreases EGFR expression and EGF-mediated tumorigenicity by promoting Rab5 activity in gastric cancer

Identification of the CD8+ T-cell Related Signature for Predicting the Prognosis of Gastric Cancer Based on Integrated Analysis of Bulk and Single-cell RNA Sequencing Data

The infiltration of CD8+ T cells in the tumor microenvironment is associated with better survival and immunotherapy response. However, their roles in gastric cancer have not been explored so far. In here, the profiles of GC gene expression were collected from The Cancer Genome Atlas database. Single-cell transcriptomic data originated from GSE134520. Cell clustering, annotation, and CD8+ T-cell differential genes were from the TISCH database. We determined 896 CD8+ T-cell differential genes by scRNA-seq analysis. After integrating immune-related genes, 174 overlapping genes were obtained and a novel risk model was subsequently built. The performance of CD8+ T-cell-associated gene signature was assessed in the training and external validation sets. The gene signature showed independent risk factors of overall survival for GC. A quantitative nomogram was built to enhance the clinical efficacy of this signature. Furthermore, low-risk individuals showed higher mutation status, higher immune checkpoint expression, low Tumour Immune Dysfunction and Exclusion (TIDE) scores, and higher IPS-PD-1 combined IPS-CTLA4 scores, indicating a greater response to immunotherapy. In addition, analysis of IMvigor210 immunotherapy cohort demonstrated that low-risk individuals had a favorable response to prognosis and immunotherapy. In conclusion, we generated a CD8+ T-cell-related signature that can serve as a promising tool for personalized prognosis prediction and guiding decisions regarding immunotherapy in GC patients.

Exploration of signature based on T cell-related genes in stomach adenocarcinoma by analysis of single cell sequencing data

BACKGROUND

Gastric cancer (GC) is a leading reason for the death of cancer around the world. The immune microenvironment counts a great deal in immunotherapy of advanced tumors, in which T cells exert an indispensable function.

METHODS

Single-cell RNA sequencing data were utilized to characterize the expression profile of T cells, followed by T cell-related genes (TCRGs) to construct signature and measure differences in survival time, enrichment pathways, somatic mutation status, immune status, and immunotherapy between groups.

RESULTS

The complex tumor microenvironment was analyzed by scRNA-seq data of GC patients. We screened for these T cell signature expression genes and the TCRGs-based signature was successfully constructed and relied on the riskscore grouping. In gene set enrichment analysis, it was shown that pro-tumor and suppressive immune pathways were more abundant in the higher risk group. We also found different infiltration of immune cells in two groups, and that the higher risk samples had a poorer response to immunotherapy.

CONCLUSION

Our study established a prognostic model, in which different groups had different prognosis, immune status, and enriched features. These results have provided additional insights into prognostic evaluation and the development of highly potent immunotherapies in GC.

Simvastatin/hydrogel-loaded 3D-printed titanium alloy scaffolds suppress osteosarcoma via TF/NOX2-associated ferroptosis while repairing bone defects

Postoperative anatomical reconstruction and prevention of local recurrence after tumor resection are two vital clinical challenges in osteosarcoma treatment. A three-dimensional (3D)-printed porous Ti6Al4V scaffold (3DTi) is an ideal material for reconstructing critical bone defects with numerous advantages over traditional implants, including a lower elasticity modulus, stronger bone-implant interlock, and larger drug-loading space. Simvastatin is a multitarget drug with anti-tumor and osteogenic potential; however, its efficiency is unsatisfactory when delivered systematically. Here, simvastatin was loaded into a 3DTi using a thermosensitive poly (lactic-co-glycolic) acid (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel as a carrier to exert anti-osteosarcoma and osteogenic effects. Newly constructed simvastatin/hydrogel-loaded 3DTi (Sim-3DTi) was comprehensively appraised, and its newfound anti-osteosarcoma mechanism was explained. Specifically, in a bone defect model of rabbit condyles, Sim-3DTi exhibited enhanced osteogenesis, bone in-growth, and osseointegration compared with 3DTi alone, with greater bone morphogenetic protein 2 expression. In our nude mice model, simvastatin loading reduced tumor volume by 59%-77 % without organic damage, implying good anti-osteosarcoma activity and biosafety. Furthermore, Sim-3DTi induced ferroptosis by upregulating transferrin and nicotinamide adenine dinucleotide phosphate oxidase 2 levels in osteosarcoma both in vivo and in vitro. Sim-3DTi is a promising osteogenic bone substitute for osteosarcoma-related bone defects, with a ferroptosis-mediated anti-osteosarcoma effect.

Research insights into the chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM): their roles in various tumors

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing (CMTM) family includes CMTM1-8 and CKLF, and they play key roles in the hematopoietic, immune, cardiovascular, and male reproductive systems, participating in the physiological functions, cancer, and other diseases associated with these systems. CMTM family members activate and chemoattract immune cells to affect the proliferation and invasion of tumor cells through a similar mechanism, the structural characteristics typical of chemokines and transmembrane 4 superfamily (TM4SF). In this review, we discuss each CMTM family member's chromosomal location, involved signaling pathways, expression patterns, and potential roles, and mechanisms of action in pancreatic, breast, gastric and liver cancers. Furthermore, we discuss several clinically applied tumor therapies targeted at the CMTM family, indicating that CMTM family members could be novel immune checkpoints and potential targets effective in tumor treatment.

Explore the active ingredients and potential mechanisms of JianPi QingRe HuaYu Methods in the treatment of gastric inflammation-cancer transformation by network pharmacology and experimental validation

BACKGROUND

JianPi QingRe HuaYu Methods (JQH) have been long used to treat chronic atrophic gastritis (CAG) and precancerous lesions of gastric cancer (PLGC). However, whether JQH can inhibit the transformation of gastritis to gastric cancer (GC) remains unclear.

METHODS

Herein, we first retrieved the active ingredients and targets of JQH from the TCMSP database and the targets related to the gastric inflammation-cancer transformation from public databases. Differentially expressed genes (DEGs) related to gastric inflammation-cancer transformation were identified from the Gene Expression Omnibus (GEO) database. Then, we obtained the potential therapeutic targets of JQH in treating gastric inflammation-cancer transformation by intersecting drugs and disease targets. The Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) analyses of the potential therapeutic targets were conducted using R software. Next, we conducted molecular docking and in vitro experiments to validate our results.

RESULTS

We obtained 214 potential therapeutic targets of JQH by intersecting drugs and disease targets. We found that the potential mechanisms of JQH in treating gastric inflammation-cancer transformation might be related to JAK-STAT, Wnt, p53 and VEGF signaling pathways. The molecular docking indicated that quercetin, as the main active ingredient of JQH, might inhibit gastric inflammation-cancer transformation by binding with specific receptors. Our experimental results showed that quercetin inhibited cells proliferation (P < 0.001), promoted cell apoptosis (P < 0.001), reduced the secretion of pro-inflammatory cytokines (P < 0.001) and promoted the secretion of anti-inflammatory cytokines (P < 0.001) in MNNG-induced GES-1 cells. Furthermore, quercetin inhibited cells proliferation (P < 0.001) and reduced mRNA and protein level of markers of PLGC (P < 0.001) in CDCA-induced GES-1 cells.

CONCLUSION

These results provide the material basis and regulatory mechanisms of JQH in treating gastric inflammation-cancer transformation.

microRNA-378a-3p plays a regulatory role in trophoblast cell function in preeclampsia by targeting CMTM3

BACKGROUND

Preeclampsia (PE) is a potential multisystemic disease in the middle and late pregnancy. Although its precise etiology and pathogenesis remain unknown, it is a significant cause of morbidity and mortality in both pregnant women and newborns. This study explored the effects of the miR-378a-3p/CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) upon the trophoblast biological functions in PE.

METHODS

The placental pathology of PE were identified by hematoxylin-eosin (HE) staining, and miR-378a-3p expression in placental tissues of PE was verified by RT-qPCR. Trophoblast cells (HTR-8/SVneo and JEG-3) were treated with lipopolysaccharide (LPS), and cell counting kit-8 (CCK-8) assay, flow cytometry, scratch assay, and Transwell assay were carried out to measure cell viability, apoptosis, migratory and invasive capacities, respectively. Western blot was performed to determine the expression levels of the cell migration-related proteins. The binding of miR-378a-3p to CMTM3 was verified through a dual-luciferase reporter gene assay.

RESULTS

miR-378a-3p expression levels were down-regulated in placental tissues and primary trophoblast cells from women with PE compared to the control group. The overexpression of miR-378a-3p promoted the capabilities of LPS-treated trophoblast cells to proliferate, migrate and invade. In contrast, it impeded cell apoptosis, promoted matrix metallopeptidase (MMP)-2 and MMP-9 expression and inhibiting TIMP metallopeptidase inhibitor (TIMP)-1 and TIMP-2 expression. Regarding the molecular mechanism, miR-378a-3p was chosen as the target to modulate the expression level of CMTM3. CMTM3 expression was increased in placental tissues and primary trophoblast cells from women with PE compared to the control group. CMTM3 overexpression could partially neutralize the effects of the overexpressed miR-378a-3p on trophoblast cell function and the expression levels of migration-associated proteins.

CONCLUSION

Our study provides a foundation for miRNA-targeted therapy for preeclampsia by establishing for the first time a potential role for the miR-378a-3p/CMTM3 axis in regulating trophoblast cell activities by altering the expression of migration-related proteins.

Current Opinions on the Relationship Between CMTM Family and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a typically malignant tumor in the digestive system. The mortality of HCC ranks third place in the world, second only to lung cancer and colorectal cancer. For the characteristics of high invasiveness, high metastasis, high recurrence rate as well as short survival time, HCC treatment has always been difficult in clinical practice. Many causes have contributed to the appearance of these features, including insidious onset, high degree of malignancy, lack of effective early molecular diagnostic markers, and disease prediction models. The human chemokine-like factor superfamily (CMTMs) is a new gene family consisting of CKLF and CMTM1-CMTM8. CMTMs have a marvel domain which can activate and chemotaxis immune cells. Many studies have reported that CMTMs are involved in the regulation of cell growth and development, and play an important role in the malignant progression of the immune system and reproductive system, especially in the development of tumors. In this review, we summarized the structure and function of the human CMTMs, the relationship between its family members and HCC, the prognostic value, potential functions, and mechanisms in HCC. CMTMs could provide a new diagnostic and therapeutic target in clinical practice for patients with HCC.

Loss of the Novel Myelin Protein CMTM5 in Multiple Sclerosis Lesions and Its Involvement in Oligodendroglial Stress Responses

This study comprehensively addresses the involvement of the protein CKLF-like Marvel transmembrane domain-containing family member 5 (CMTM5) in the context of demyelination and cytodegenerative autoimmune diseases, particularly multiple Sclerosis (MS). An observed reduction in CMTM5 expression in post-mortem MS lesions prompted further investigations in both in vitro and in vivo animal models. In the cuprizone animal model, we detected a decrease in CMTM5 expression in oligodendrocytes that is absent in other members of the CMTM protein family. Our findings also confirm these results in the experimental autoimmune encephalomyelitis (EAE) model with decreased CMTM5 expression in both cerebellum and spinal cord white matter. We also examined the effects of a Cmtm5 knockdown in vitro in the oligodendroglial Oli-neu mouse cell line using the CRISPR interference technique. Interestingly, we found no effects on cell response to thapsigargin-induced endoplasmic reticulum (ER) stress as determined by Atf4 activity, an indicator of cellular stress responses. Overall, these results substantiate previous findings suggesting that CMTM5, rather than contributing to myelin biogenesis, is involved in maintaining axonal integrity. Our study further demonstrates that the knockdown of Cmtm5 in vitro does not modulate oligodendroglial responses to ER stress. These results warrant further investigation into the functional role of CMTM5 during axonal degeneration in the context of demyelinating conditions.

CMTM3 deficiency induces cardiac hypertrophy by regulating MAPK/ERK signaling

OBJECTIVES

Cardiac hypertrophy is the heart's compensatory response stimulated by various pathophysiological factors. However, prolonged cardiac hypertrophy poses a significant risk of progression to heart failure, lethal arrhythmias, and even sudden cardiac death. For this reason, it is crucial to effectively prevent the occurrence and development of cardiac hypertrophy. CMTM is a superfamily of human chemotaxis, which is involved in immune response and tumorigenesis. CMTM3 expressed widely in tissues, including the heart, but its cardiac function remains unclear. This research aims to explore the effect and mechanism of CMTM3 in the development of cardiac hypertrophy.

METHODS AND RESULTS

We generated a Cmtm3 knockout mouse model (Cmtm3^-/-) as the loss-of-function approach. CMTM3 deficiency induced cardiac hypertrophy and further exacerbated hypertrophy and cardiac dysfunction stimulated by Angiotensin Ⅱ infusion. In Ang Ⅱ-infusion stimulated hypertrophic hearts and phenylephrine-induced hypertrophic neonatal cardiomyocytes, CMTM3 expression significantly increased. However, adenovirus-mediated overexpression of CMTM3 inhibited the hypertrophy of rat neonatal cardiomyocytes induced by PE stimulation. In terms of mechanism, RNA-seq data revealed that Cmtm3 knockout-induced cardiac hypertrophy was related to MAPK/ERK activation. In vitro, CMTM3 overexpression significantly inhibited the increased phosphorylation of p38 and ERK induced by PE stimulation.

CONCLUSIONS

CMTM3 deficiency induces cardiac hypertrophy and aggravates hypertrophy and impaired cardiac function stimulated by angiotensin Ⅱ infusion. The expression of CMTM3 increases during cardiac hypertrophy, and the increased CMTM3 can inhibit further hypertrophy of cardiomyocytes by inhibiting MAPK signaling. Thus, CMTM3 plays a negative regulatory effect in the occurrence and development of cardiac hypertrophy.

CMTM3 protects the gastric epithelial cells from apoptosis and promotes IL-8 by stabilizing NEMO during Helicobacter pylori infection

BACKGROUND

CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) plays an important role in cancer development. Although Helicobacter pylori (H. pylori) infection is a main cause of gastric cancer, the function of CMTM3 during H. pylori infection remains unclear. CMTM3 expression levels in tissues from H. pylori-infected patients and cells co-cultured with H. pylori were analyzed. qRT-PCR and ELISA were used to investigate the effects of CMTM3 on interleukin 8 (IL-8) expression. Annexin V/propidium iodide staining was performed to evaluate the function of CMTM3 in the apoptosis of gastric epithelial cells. Proteomic analysis was performed to explore the underlying mechanism of CMTM3 during H. pylori infection. The interaction between CMTM3 and NEMO was determined via co-immunoprecipitation, HA-ubiquitin pull-down assay, and immunofluorescence.

RESULTS

H. pylori induced a significant increase in CMTM3 expression. CMTM3 inhibited gastric mucosal epithelial cells from apoptosis and increased the expression level of IL-8 during H. pylori infection. KEGG pathway enrichment analysis revealed that differentially expressed proteins were involved in epithelial cell signaling in H. pylori infection. CMTM3 directly interacted with NEMO, which promoted protein stabilization by down-regulation of its ubiquitylation.

CONCLUSIONS

CMTM3 reduces apoptosis and promotes IL-8 expression in the gastric epithelial cells by stabilizing NEMO during H. pylori infection. These findings characterize a new role for CMTM3 in host-pathogen interactions and provide novel insight into the molecular regulation of NEMO.

In vivo study revealed pro-tumorigenic effect of CMTM3 in hepatocellular carcinoma involving the regulation of peroxisome proliferator-activated receptor gamma (PPARγ)

PURPOSE

To clarify the ambiguity of the function of CMTM3 in the development of hepatocellular carcinoma (HCC) and explore its molecular mechanism.

METHODS

The Cmtm3-KO C57BL/6 mouse strain was established using CRISPR-Cas9. Acute liver damage and HCC models were induced by peritoneal injection of 100 or 25 mg/kg.BW N-Nitrosodiethylamine (DEN) to male mice. Liver function and histology were evaluated by blood serum levels of AST and ALT, and HE staining. Gene and protein expression in liver tissues was investigated by RNA-seq, RT-qPCR, Western blotting, immunohistochemistry, and immunofluorescence. Protein-protein interactions were studied by STRING and topological measures. The mRNA expression of CMTM3 and PPARs and patient survival were analyzed using the UALCAN database.

RESULTS

Global knockout of Cmtm3 in KO mice was successfully confirmed. Cmtm3 knockout alleviated DEN-induced acute damage to liver histological integrity and liver function, reduced DNA damage and apoptosis, and also caused a significantly reduced number (WT: 8.7 ± 5.5 vs. KO: 2.7 ± 3.1, P = 0.0394) and total size of tumors (WT: 130.9 ± 181.8 mm² vs. KO: 9.3 ± 11.5 mm², P = 0.026) in the liver. Mechanistically, Cmtm3 knockout resulted in reduced expression and inactivation of Pparγ and its downstream lipid metabolism genes (e.g. Adipoq) upon DEN intoxication. CMTM3 and PPARγ were both overexpressed in HCC, and higher levels of both genes were associated with worse overall survival of HCC patients.

CONCLUSION

This study clarified the pro-tumorigenesis role of CMTM3 in HCC in vivo, possibly through the upregulation of PPARγ and activation of the PPAR pathway.

CMTM3 as a Potential New Immune Checkpoint Regulator

Objectives

To evaluate the role of CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) in tumor microenvironment and cancer immunotherapy and explore its potential mechanism.

Method

The cancer genome map was obtained from the UCSC Xena database. RNAseq data from the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases were utilized for evaluating the expression and prognostic value of CMTM3 through survival data of clinical trials. The enrichment analysis of CMTM3 was performed using the R package “clusterProfiler.” The scores of immune cell infiltration in TCGA samples were downloaded from the ImmuCellAI database and TIMER2 database, and the relationship between both immune cell invasion and CMTM3 expression was investigated. Immunological activation and suppression genes, immune checkpoints, chemokines, and their receptors were all investigated in relation to CMTM3.

Results

Most tumor types had varied levels of CMTM3 expression and predicted poor survival status. The CMTM3 expression is closely associated with cancer-associated fibroblasts, macrophages, myeloid dendritic cells, endothelial cells, immune activation genes, immune suppressor genes, immune checkpoints, chemokines, and related receptors.

Conclusion

Our data reveal that CMTM3 might be used as a cancer biomarker. CMTM3 may work in conjunction with other immunological checkpoints to alter the immune milieu, which could lead to the establishment of new immunotherapy medicines.

CMTM Family and Gastrointestinal Tract Cancers: A Comprehensive Review

Gastrointestinal tract cancers are a highly heterogeneous group of malignant diseases, contributing significantly to the burden of death worldwide. Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTMs) plays important roles in cancer development and progression. Since the first member was cloned, there have been abundant studies on the relationships between the CMTM family and human cancers. It has been reported that the CMTM family has a large potential prognostic value for multiple cancers. Meanwhile, upregulated or downregulated expression of the family members was related to advanced tumor stage, metastasis, and overall survival. Studies have also reported that these proteins play critical roles in antitumor immunity. We performed a systematic review to sum up the latest advances of CMTM family’ roles in gastrointestinal tract cancers, with a primary focus on hepatocellular carcinoma and gastric carcinoma.

The efficacy and safety of neoadjuvant nimotuzumab for gastric cancer: A meta-analysis of randomized controlled studies

INTRODUCTION

The efficacy of neoadjuvant nimotuzumab for gastric cancer remained controversial. We conducted a systematic review and meta-analysis to explore the efficacy of neoadjuvant nimotuzumab plus chemotherapy vs chemotherapy for gastric cancer.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through May 2019, and included randomized controlled trials assessing the efficacy of neoadjuvant nimotuzumab plus chemotherapy vs chemotherapy for gastric cancer. This meta-analysis was performed using the random-effect model.

RESULTS

Four randomized controlled trials were included in the meta-analysis. There were 128 patients included in intervention group and 131 patients included in control group. Overall, compared with chemotherapy for gastric cancer, neoadjuvant nimotuzumab plus chemotherapy showed no substantial influence on response rate (risk ratio [RR] = 1.22; 95% CI = 0.78-1.89; P = .38), disease control rate (RR = 2.22; 95% confidence interval [CI] = 0.32-15.40; P = .42), rash (RR = 1.26; 95% CI = 0.96-1.66; P = .10), neutropenia (RR = 1.26; 95% CI = 0.96-1.66; P = .10), anemia (RR = 1.08; 95% CI = 0.62-1.89; P = .78), or nausea (RR = 1.19; 95% CI = 0.96-1.48; P = .12), but might improve the incidence of vomiting (RR = 1.60; 95% CI = 1.03-2.50; P = .04).

CONCLUSIONS

Neoadjuvant nimotuzumab might provide no additional benefits to the treatment of gastric cancer.

Role of Endocytosis Proteins in Gefitinib-Mediated EGFR Internalisation in Glioma Cells

EGFR (epidermal growth factor receptor), a member of the ErbB tyrosine kinase receptor family, is a clinical therapeutic target in numerous solid tumours. EGFR overexpression in glioblastoma (GBM) drives cell invasion and tumour progression. However, clinical trials were disappointing, and a molecular basis to explain these poor results is still missing. EGFR endocytosis and membrane trafficking, which tightly regulate EGFR oncosignaling, are often dysregulated in glioma. In a previous work, we showed that EGFR tyrosine kinase inhibitors, such as gefitinib, lead to enhanced EGFR endocytosis into fused early endosomes. Here, using pharmacological inhibitors, siRNA-mediated silencing, or expression of mutant proteins, we showed that dynamin 2 (DNM2), the small GTPase Rab5 and the endocytosis receptor LDL receptor-related protein 1 (LRP-1), contribute significantly to gefitinib-mediated EGFR endocytosis in glioma cells. Importantly, we showed that inhibition of DNM2 or LRP-1 also decreased glioma cell responsiveness to gefitinib during cell evasion from tumour spheroids. By highlighting the contribution of endocytosis proteins in the activity of gefitinib on glioma cells, this study suggests that endocytosis and membrane trafficking might be an attractive therapeutic target to improve GBM treatment.

CMTM5 inhibits the development of prostate cancer via the EGFR/PI3K/AKT signaling pathway

Prostate cancer (PCa) endangers the life and health of older men. Most PCa cases develop into castration-resistant PCa (CRPC) within 2 years. At present, the molecular mechanisms of the occurrence and development of PCa and its transformation to CRPC remain unknown. The present study aimed to investigate the role of CKLF-like Marvel transmembrane domain containing family member 5 (CMTM5) in PCa and its molecular mechanism in vitro. PCa tissues and paired adjacent normal prostate tissues from 70 patients were collected to examine the expression levels of CMTM5 and EGFR via immunohistochemistry, reverse transcription-quantitative PCR and western blotting. Then, CMTM5-overexpressing DU145 cells were constructed, and CMTM5 expression in these transfected cells and vector control cells was examined via western blotting. Cell Counting Kit-8 and plate clone formation assays were used to evaluate the proliferation and colony number of CMTM5-overexpressing cells and vector control cells. Then, cell migration and invasion were assessed using wound healing assay, Transwell assay and immunofluorescence analysis with DAPI staining. The effect of CMTM5 on apoptosis and its underlying molecular mechanism were examined using western blotting and flow cytometry. The results demonstrated that CMTM5 expression in PCa tissues and cell lines was significantly downregulated, while EFGR expression was significantly upregulated. The proportion of high CMTM5 expression in PCa tissues was significantly lower compared with that in normal prostate tissues. By contrast, the proportion of high EGFR expression in PCa tissues was significantly increased compared with that in normal prostate tissues. Moreover, CMTM5 overexpression significantly inhibited cell proliferation, migration and invasion, and promoted cell apoptosis compared with vector control cells in vitro. Furthermore, the regulation of PCa by CMTM5 was associated with the downregulation of PI3K/AKT and its downstream Bcl-2 expression, as well as the upregulation of Bax expression. In conclusion, CMTM5 may be an effective tumor suppressor gene for PCa, especially for castration-resistant PCa, by downregulating EGFR and PI3K/AKT signaling pathway components.

CMTM3 suppresses bone formation and osteogenic differentiation of mesenchymal stem cells through inhibiting Erk1/2 and RUNX2 pathways

Osteoporosis, fracture, large-scale craniofacial defects and osteonecrosis are hot topics and are still underdiagnosed and undertreated in the clinic. It is urgent to understand the molecular mechanisms corresponding to the regulation of bone formation. CMTM3 (CKLF-like MARVEL transmembrane domain containing 3) connects the classic chemokine to the transmembrane 4 superfamily and plays an important role in intracellular vesicles transport, EGF receptor function maintenance and cancer development. However, its expression and function in bone remain unclear. In this paper, we found that the bone volume/total volume, trabecular number, trabecular thickness and bone surface area/bone volume of Cmtm3 KO mice increased significantly, and trabecular separation and trabecular pattern factor decreased in Cmtm3 KO mice compared with WT mice by microcomputed tomography. Moreover, the bone mineral content, bone mineral density, ultimate force and stiffness were also increased in Cmtm3 KO mice. Using in vitro analysis, we showed that CMTM3 expression decreases during the differentiation of hBMSCs to osteoblasts. Knockdown of CMTM3 promoted ALP and mineralization of hBMSCs and facilitated osteoblastic differentiation with increasing RUNX2 expression. However, overexpression of CMTM3 got the opposite results. These results proved that CMTM3 was essential for osteogenic differentiation. In addition, knockdown of CMTM3 enhanced p-Erk1/2, but had no significant effect on p-Akt or p-STAT3 in hBMSCs and MC3T3-E1 cells. Taken together, our results indicated that Erk1/2 and RUNX2 pathways mediated by CMTM3 were involved in the process of osteogenic differentiation, and CMTM3 might be a new potential target in the treatment of bone formation-related disease.

Direct interaction between Rab5a and Rab4a enhanced epidermal growth factor-stimulated proliferation of gastric cancer cells

BACKGROUND

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Although targeted therapies such as antibodies against human epidermal growth factor receptor 2 or vascular endothelial growth factor receptor 2 have been widely used in the treatment of metastatic cancer, the overall outcomes are poor. Therefore, elucidation of the mechanism underlying cancer progression is important to improve prognosis. Overexpression of the Rab5a gene has been confirmed to correlate with tumorigenesis of many cancers, but the mechanism underling, especially of GC, is still unclear.

AIM

To investigate the effects of Rab5a overexpression on the tumorigenesis of GC.

METHODS

First, the expression levels of Rab5a and Rab4a in primary tumorous tissues of GC patients diagnosed between 2015 and 2018 were analyzed. Then we constructed HGC-27 cell lines overexpressing green fluorescent protein-Rab5a or red fluorescent protein-Rab4a and investigated the interaction between Rab5a or Rab4a using Western blotting, co-immunoprecipitation, confocal microscopy, and colocalization analysis. Finally, epidermal growth factor-stimulated proliferation of these cell lines was analyzed using cell counting kit-8 cell viability assay.

RESULTS

Compared with normal gastric tissues, the expression levels of Rab5a and Rab4a increased progressively both in paracancerous tissues and in advanced cancerous tissues. Epidermal growth factor could promote the proliferation of HGC-27 cells, especially Rab5a-overexpressing HGC-27 cells. Notably, Rab5a and Rab4a co-overexpression promoted the proliferation of HGC-27 cells to the greatest extent. Further analysis identified a direct interaction between Rab5a and Rab4a in HGC-27 cells.

CONCLUSION

Co-overexpression of Rab5a and Rab4a in GC may promote the endosomal recycling of epidermal growth factor receptor, which in turn contributes to poor prognosis and tumor progression in GC patients. Inhibition of Rab5a or Rab4a expression might be a promising therapy for refractory GC.

CMTM3 suppresses chordoma progress through EGFR/STAT3 regulated EMT and TP53 signaling pathway

BACKGROUND

Chordomas are rare, slow-growing and locally aggressive bone sarcomas. At present, chordomas are difficult to manage due to their high recurrence rate, metastasis tendency and poor prognosis. The underlying mechanisms of chordoma tumorigenesis and progression urgently need to be explored to find the effective therapeutic targets. Our previous data demonstrates that EGFR plays important roles in chordoma development and CKLF-like MARVEL transmembrane domain containing (CMTM)3 suppresses gastric cancer metastasis by inhibiting the EGFR/STAT3/EMT signaling pathway. However, the roles and mechanism of CMTM3 in chordomas remain unknown.

METHODS

Primary chordoma tissues and the paired adjacent non-tumor tissues were collected to examine the expression of CMTM3 by western blot. The expression of CMTM3 in chordoma cell lines was tested by Real-time PCR and western blot. CCK-8 and colony forming unit assay were performed to delineate the roles of CMTM3 in cell proliferation. Wound healing and Transwell assays were performed to assess cell migration and invasion abilities. A xenograft model in NSG mice was used to elucidate the function of CMTM3 in vivo. Signaling pathways were analyzed by western blot and IHC. RNA-seq was performed to further explore the mechanism regulated by CMTM3 in chordoma cells.

RESULTS

CMTM3 expression was downregulated in chordoma tissues compared with paired normal tissues. CMTM3 suppressed proliferation, migration and invasion of chordoma cells in vitro and inhibited tumor growth in vivo. CMTM3 accelerated EGFR degradation, suppressed EGFR/STAT3/EMT signaling pathway, upregulated TP53 expression and enriched the TP53 signaling pathway in chordoma cells.

CONCLUSIONS

CMTM3 inhibited tumorigenesis and development of chordomas through activating the TP53 signaling pathway and suppressing the EGFR/STAT3 signaling pathway, which suppressed EMT progression. CMTM3 might be a potential therapeutic target for chordomas.

Establishment of an Endocytosis-Related Prognostic Signature for Patients With Low-Grade Glioma

Background

Low-grade glioma (LGG) is a heterogeneous tumor that might develop into high-grade malignant glioma, which markedly reduces patient survival time. Endocytosis is a cellular process responsible for the internalization of cell surface proteins or external materials into the cytosol. Dysregulated endocytic pathways have been linked to all steps of oncogenesis, from initial transformation to late invasion and metastasis. However, endocytosis-related gene (ERG) signatures have not been used to study the correlations between endocytosis and prognosis in cancer. Therefore, it is essential to develop a prognostic model for LGG based on the expression profiles of ERGs.

Methods

The Cancer Genome Atlas and the Genotype-Tissue Expression database were used to identify differentially expressed ERGs in LGG patients. Gene ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene set enrichment analysis methodologies were adopted for functional analysis. A protein-protein interaction (PPI) network was constructed and hub genes were identified based on the Search Tool for the Retrieval of Interacting Proteins database. Univariate and multivariate Cox regression analyses were used to develop an ERG signature to predict the overall survival (OS) of LGG patients. Finally, the association between the ERG signature and gene mutation status was further analyzed.

Results

Sixty-two ERGs showed distinct mRNA expression patterns between normal brain tissues and LGG tissues. Functional analysis indicated that these ERGs were strikingly enriched in endosomal trafficking pathways. The PPI network indicated that EGFR was the most central protein. We then built a 29-gene signature, dividing patients into high-risk and low-risk groups with significantly different OS times. The prognostic performance of the 29-gene signature was validated in another LGG cohort. Additionally, we found that the mutation scores calculated based on the TTN, PIK3CA, NF1, and IDH1 mutation status were significantly correlated with the endocytosis-related prognostic signature. Finally, a clinical nomogram with a concordance index of 0.881 predicted the survival probability of LGG patients by integrating clinicopathologic features and ERG signatures.

Conclusion

Our ERG-based prediction models could serve as an independent prognostic tool to accurately predict the outcomes of LGG.

Comprehensive analysis of the prognostic value of the chemokine-like factor-like MARVEL transmembrane domain-containing family in gastric cancer

Background

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing (CMTM) family refers to a family of transcriptional repressor genes. CMTMs are closely associated with the epigenetic regulatory mechanisms and development of multiple malignancies, including gastric cancer. However, their specific biological functions and prognostic values in gastric cancer have yet to be elucidated.

Methods

Tumor sample datasets were retrieved and analyzed using databases including Oncomine, STRING, GEPIA2, cBioportal, and Kaplan-Meier plotter. To investigate the prognostic role of CMTMs in gastric cancer, we applied unsupervised hierarchical clustering analysis of CMTM gene expression patterns.

Results

While the mRNA levels of CMTM1/3/6/7/8 were upregulated in gastric cancer, CMTM2/4/5 showed no statistically significant difference at the mRNA level in patients with gastric cancer. Moreover, the mRNA expressions of different CMTMs exhibited strong correlations with various clinical parameters of patients with gastric cancer, including tumor stage, metastatic lymph node status, H. pylori status, and tumor grade. Also, the results suggested that elevated levels of CMTM3/5 mRNA had a significant association (P<0.05) with poor overall survival, progression-free survival, and post-progression survival. Conversely, elevated expression of CMTM2/4/6 mRNA had a significant association with better overall survival, progression-free survival, and post-progression survival. Unsupervised hierarchical clustering analysis successfully identified 2 major clusters of patients as follows: signature #1: CMTM4/6/8 and signature #2: CMTM1/2/3/5/7. Signature #2 was closely correlated with poorer overall survival, which indicated that the expression pattern of the CMTM family could be a novel prognostic factor for patients with gastric cancer.

Conclusions

These results suggest that the expression levels of CMTM genes possibly have prognostic value as a biomarker of gastric cancer.

Possible effects of chemokine-like factor-like MARVEL transmembrane domain-containing family on antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease defined by thrombotic or obstetrical events and persistent antiphospholipid antibodies (aPLs). Chemokine-like factor-like MARVEL transmembrane domain-containing family (CMTM) is widely expressed in the immune system and may closely related to APS. This review aimed to systematically summarize the possible effects of CMTM on APS. Publications were collected from PubMed and Web of Science databases up to August 2020. CKLF, CKLFSF, CMTM, antiphospholipid syndrome, immune cells, and immune molecules were used as search criteria. Immune cells, including neutrophil, dendritic cells (DCs), T-cells, B-cells, and inflammatory cytokines, play an important role in the development of APS. Chemokine-like factor 1 (CKLF1) has a chemotactic effect on many cells and can affect the expression of inflammatory cytokines and adhesion molecules through the nuclear factor-kB (NF-kB) pathway or mitogen-activated protein kinase (MARK) pathway. CKLF1 can participate in the maturation of DCs, T lymphocyte activation, and the activation of neutrophils through the MAPK pathway. CMTM1 may act on Annexin A2 by regulating Ca²⁺ signaling. CMTM2 and CMTM6 are up-regulated in neutrophils of APS patients. Some CMTM family members influence the activation and accumulation of platelets. CMTM3 and CMTM7 are binding partners of B-cell linker protein (BLNK), thereby linking B cell receptor (BCR) and activating BLNK-mediated signal transduction in B cells. Moreover, CMTM3 and CMTM7 can act on DCs and B-1a cell development, respectively. CMTM may have potential effects on the development of APS by acting on immune cells and immune molecules. Thus, CMTM may act as a novel prognostic factor or immunomodulatory treatment option of APS.

Expression and biological function of CMTM3 in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common malignant tumors in the digestive system with a poor prognosis. The 5-year survival rate of patients with advanced stage GC is low, and most patients have locally advanced or metastatic disease when initially diagnosed, and have therefore lost the opportunity of surgery. The exact molecular mechanism of GC is still unclear.

AIM

To investigate the expression, biological function, and potential molecular regulatory mechanism of CMTM3 gene in GC by bioinformatics analysis and cellular experiments.

METHODS

The differential expression of CMTM3 gene was analyzed in GEO and TCGA databases, and the relationship between CMTM3 gene expression and the prognosis of GC patients was compared. The expression of CMTM3 gene was compared between normal gastric epithelial cells (GES-1) and several GC cell lines (HGC-27, BGC-823, and MKN45). After transfection of exogenous small interfering RNA (sh-CMTM3-1) into MKN45 cells, cell proliferation and migration were evaluated by MTT assay and scratch test. The differentially expressed microRNA profiles in GC tissues and normal gastric tissues were screened from the GEO database, and the upstream target gene miR-125b-5p of CMCT3 was predicted according to the microRNA online prediction software TargetScan. The expression levels of CMTM3 and miR-125b-5p were detected by qPCR in 15 patients with GC at our hospital. Double luciferase reporter assay was performed to verify the relationship between miR-125b-5p and CMTM3 targeted regulation. The proliferation and migration of MKN45 cells were evaluated by transfection of exogenous miR-125b-5p-mimic.

RESULTS

The expression of CMTM3 mRNA in GC tissues was significantly higher than that in adjacent normal gastric tissues (P < 0.05). The overall survival (OS) and disease free survival (DFS) of GC patients with high expression of CMTM3 gene were lower than those of patients with low expression of CMTM3. Exogenous small interfering RNA (sh-CMTM3-1) significantly down-regulated the expression of CMTM3 gene in MKN45 GC cells (P < 0.05). After sh-CMTM3-1-mediated down-regulation of the expression of CMTM3 gene in MKN45 GC cells, cell migration and proliferation were significantly reduced (P < 0.05). The upstream target gene miR-125b-5p of CMTM3 was screened. The expression level of miR-125b-5p in normal gastric mucosa cell line GES-1 was significantly higher than that in GC cell lines (P < 0.05). The expression level of miR-125b-5p in GC tissues was significantly lower than that in adjacent normal tissues (P < 0.05). The expression level of CMTM3 gene in GC tissues was significantly higher than that in adjacent tissues (P < 0.05). There was a negative correlation between the expression of CMTM3 and miR-125b-5p in GC (r_pearson = -0.58, P < 0.05). In MKN45 cells, miR-125b-5p significantly down-regulated the expression of CMTM3 gene (P < 0.05). Double luciferase reporter assay showed that miR-125b-5p gene can bind the 3'-untranslated region of CMTM3 gene. After transfection of miR-125b-5p-mimic to down-regulate the expression of CMTM3, the proliferation and migration of GC MKN45 cells were significantly decreased (P < 0.05).

CONCLUSION

MiR-125b-5p regulates the expression of CMTM3 gene and affects the proliferation and migration of GC. CMTM3 is expected to become a molecular marker and potential therapeutic target for GC.

microRNAs Promoting Growth of Gastric Cancer Xenografts and Correlation to Clinical Prognosis

The annual death toll for gastric cancer is in the range of 700,000 worldwide. Even in patients with early-stage gastric cancer recurrence within five years has been observed after surgical resection and following chemotherapy with therapy-resistant features. Therefore, the identification of new targets and treatment modalities for gastric cancer is of paramount importance. In this review we focus on the role of microRNAs with documented efficacy in preclinical xenograft models with respect to growth of human gastric cancer cells. We have identified 31 miRs (-10b, -19a, -19b, -20a, -23a/b, -25, -27a-3p, -92a, -93, -100, -106a, -130a, -135a, -135b-5p, -151-5p, -187, -199-3p, -215, -221-3p, -224, -340a, -382, -421, -425, -487a, -493, -532-3p, -575, -589, -664a-3p) covering 26 different targets which promote growth of gastric cancer cells in vitro and in vivo as xenografts. Five miRs (miRs -10b, 151-5p, -187, 532-3p and -589) additionally have an impact on metastasis. Thirteen of the identified miRs (-19b, -20a/b, -25, -92a, -106a, -135a, -187, -221-3p, -340a, -421, -493, -575 and -589) have clinical impact on worse prognosis in patients.

CMTM8 as an LPA1-associated partner mediates lysophosphatidic acid-induced pancreatic cancer metastasis

Background

Lysophosphatidic acid (LPA) is known to promote cancer cell invasiveness through LPA1, but the downstream signaling cascades are still not fully clarified. The CKLF-like MARVEL transmembrane domain-containing (CMTM) family regulates aggressive phenotype in many cancers.

Methods

We performed LPA1 co-immunoprecipitation combined with mass spectrometry to search for LPA1-associated proteins. The role of CMTM8 in mediating the pro-invasive activity of LPA was investigated in pancreatic cancer.

Results

We identified CMTM8 as an LPA1-interacting protein. LPA1 and CMTM8 were co-localized in pancreatic cancer cells. LPA treatment led to stabilization of CMTM8 protein, which was impaired by knockdown of LPA1. Depletion of CMTM8 significantly suppressed the migration and invasion of pancreatic cancer cells. Conversely, ectopic expression of CMTM8 enhanced the migratory and invasive capacity of pancreatic cancer cells. CMTM8 depletion blocked the formation of metastatic lesions in the lung. Knockdown of CMTM8 attenuated LPA-induced migration and invasion in pancreatic cancer cells. CMTM8 overexpression stimulated β-catenin activation through reduction of GSK3β. In addition, knockdown of β-catenin dramatically antagonized CMTM8-mediated migration and invasion in pancreatic cancer cells.

Conclusions

CMTM8 serves as a key mediator of LPA-induced invasiveness in pancreatic cancer. The interaction between CMTM8 and LPA1 leads to activation of oncogenic β-catenin signaling. CMTM8 represents a potential therapeutic target for pancreatic cancer.

Chemokine-Like Factor-Like MARVEL Transmembrane Domain-Containing Family in Hepatocellular Carcinoma: Latest Advances

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTMs) is a new gene family, consisting of CKLF and CMTM1 to CMTM8, which plays an important role in hematopoiesis system, autoimmune diseases, male reproduction etc. Abnormal expression of CMTMs is also associated with tumor genesis, development and metastasis. In this review, we briefly describe the characteristics of CMTM family, outline its functions in multiple kinds of carcinomas, and summarize the latest research on their roles in hepatocellular carcinoma which are mainly related to the expression, prognostic effect, potential functions, and mechanism of action. The CMTM family is expected to provide new ideas and targets for HCC diagnosis and treatment.

Down-Regulated CMTM2 Promotes Epithelial-Mesenchymal Transition in Hepatocellular Carcinoma

Background

Our recent study identified that human chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family member 2 (CMTM2) was deregulated in hepatocellular carcinoma (HCC) tissues and posed as a potential tumor suppressor. However, the mechanism of CMTM2 in HCC occurrence and development has not been well elaborated.

Materials and Methods

The expression of CMTM2 was knocked-down by RNA interruption in Huh-7 and SMMC7721 cells. Cell proliferation ability was detected by CCK8 test and colony formation assay. The cell invasion and migration were measured by wound healing and Transwell assay.

Results

We found that the cell proliferation was significantly increased by interruption of CMTM2 expression, both in Huh-7 and SMMC7721 cells. Moreover, down-regulated CMTM2 could promote the invasion and migration ability of HCC cells through inducing the epithelial-mesenchymal transition (EMT) process. We further discovered that both the expression of CMTM2 and the EMT-associated marker E-cadherin were decreased in the same thirty cases of HCC tissues compared with the corresponding adjacent non-tumor tissues. Pearson correlation test showed that there was a significantly positive correlation between CMTM2 and E-cadherin in HCC tissues (P<0.05).

Conclusion

Based on the results of cell model and HCC tissues, our study suggests that down-regulated CMTM2 promotes HCC metastasis through inducing the EMT process.

1‑Palmitoyl‑2‑linoleoyl‑3‑acetyl‑rac‑glycerol ameliorates EGF‑induced MMP‑9 expression by promoting receptor desensitization in MDA‑MB‑231 cells

Activated epidermal growth factor receptors (EGFRs) are crucial for inducing metastasis in cancer cells by promoting matrix metalloproteinase (MMP) expression. The present study was designed to investigate the effects of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) on MMP expression in epidermal growth factor (EGF)-stimulated breast cancer cells in vitro. EGF stimulation induced internalization of its cognate receptor, EGFR, for stimulus-desensitization. These internalized receptors, complexed with the ubiquitin ligase c-Cbl and EGFR pathway substrate 15 (EPS15) (for degradation), were evaluated by confocal microscopy at 5–90 min time intervals. During intracellular trafficking of EGFRs, EGF-induced signaling cascades were analyzed by examining EGFR and SHC phosphorylation. Modulation of MMP expression was assessed by evaluating the activity of transcription factor AP-1 using a luciferase assay. PLAG accelerated the assembly of EGFRs with c-Cbl and EPS15 and promoted receptor degradation. This faster intracellular EGFR degradation reduced AP-1-mediated MMP expression. PLAG stimulation upregulated thioredoxin-interacting protein (TXNIP) expression, and this mediated the accelerated receptor internalization. This PLAG-induced increase in EGFR trafficking was blocked in TXNIP-silenced cells. By downregulating MMP expression, PLAG effectively attenuated EGF-induced mobility and invasiveness in these cancer cells. These data suggest that PLAG may be a potential therapeutic agent for blocking metastasis.

Essential role for Cmtm7 in cell-surface phenotype, BCR signaling, survival and Igμ repertoire of splenic B-1a cells

B-1a cells represent a distinct B cell population with unique phenotype, self-renewing capacity and restricted Igμ repertoire. They primarily locate in body cavity and also exist in spleen. The different subpopulations of B-1a cells are heavily affected by local environment. Our previous studies revealed that MARVEL-domain-containing membrane protein, CMTM7, was involved in B-1a cell development. Here, we focused its influence on peritoneal and splenic B-1a cells. Unlike peritoneal B-1a cells, we found that splenic Cmtm7^-/- B-1a cells expressed higher level of CD5, CD80 and CD86 compared with WT counterparts. They also exhibited an enhanced tonic BCR signals in steady state. Though the cell viability was unaffected in vitro, Cmtm7 knockout markedly promoted splenic B-1a cell apoptosis in situ, which was likely associated with down-regulation of Il-5rα. With regard to Igμ repertoire, peritoneal and splenic Cmtm7^-/- B-1a cells exhibit similar changes exemplified by the loss of V_H11 and gain of V_H12, whereas an increase in V_H1 usage and skewed J segments from J_H1 to J_H2 and J_H4 families could only be detected within splenic Cmtm7^-/- B-1a cells. Overall, these data indicate that Cmtm7 functions differently in peritoneal and splenic B-1a cells and plays a more important role in splenic cells.

The Emerging Role of Rab5 in Membrane Receptor Trafficking and Signaling Pathways

Ras analog in brain (Rab) proteins are small guanosine triphosphatases (GTPases) that belong to the Ras-like GTPase superfamily, and they can regulate vesicle trafficking. Rab proteins alternate between an activated (GTP-bound) state and an inactivated (GDP-bound) state. Early endosome marker Rab5 GTPase, a key member of the Rab family, plays a crucial role in endocytosis and membrane transport. The activated-state Rab5 recruits its effectors and regulates the internalization and trafficking of membrane receptors by regulating vesicle fusion and receptor sorting in the early endosomes. In this review, we summarize the role of small Rab GTPases Rab5 in membrane receptor trafficking and the activation of signaling pathways, such as Ras/MAPK and PI3K/Akt, which ultimately affect cell growth, apoptosis, tumorigenesis, and tumor development. This review may provide some insights for our future research and novel therapeutic targets for diseases.

YC-1 potentiates the antitumor activity of gefitinib by inhibiting HIF-1α and promoting the endocytic trafficking and degradation of EGFR in gefitinib-resistant non-small-cell lung cancer cells

The tyrosine kinase inhibitor (TKI) gefitinib exerts good therapeutic effect on NSCLC patients with sensitive EGFR-activating mutations. However, most patients ultimately relapse due to the development of drug resistance after 6-12 months of treatment. Here, we showed that a HIF-1α inhibitor, YC-1, potentiated the antitumor efficacy of gefitinib by promoting EGFR degradation in a panel of human NSCLC cells with wild-type or mutant EGFRs. YC-1 alone had little effect on NSCLC cell survival but significantly enhanced the antigrowth and proapoptotic effects of gefitinib. In insensitive NSCLC cell lines, gefitinib efficiently inhibited the phosphorylation of EGFR but not the downstream signaling of ERK, AKT and STAT3; however, when combined with YC-1 treatment, these signaling pathways were strongly impaired. Gefitinib treatment induced EGFR arrest in the early endosome, and YC-1 treatment promoted delayed EGFR transport into the late endosome as well as receptor degradation. Moreover, the YC-1-induced reduction of HIF-1α protein was associated with the enhancement of EGFR degradation. HIF-1α knockdown promoted EGFR degradation, showing synergistic antigrowth and proapoptotic effects similar to those of the gefitinib and YC-1 combination treatment in NSCLC cells. Our findings provide a novel combination treatment strategy with gefitinib and YC-1 to extend the usage of gefitinib and overcome gefitinib resistance in NSCLC patients.

CMTM7 plays key roles in TLR-induced plasma cell differentiation and p38 activation in murine B-1 B cells

Terminal differentiation of B cells into antibody-secreting cells is the foundation of humoral immune response. B-1 cells, which are different from B-2 cells, preferentially differentiate into plasma cells. CMTM7 is a MARVEL-domain-containing membrane protein predominantly expressed in B cells that plays an important role in B-1a cell development. The present study assessed CMTM7 function in response to antigen stimulation. Following immunization with T cell-dependent and T cell-independent antigens, Cmtm7-deficient mice exhibited decreased IgM but normal IgG responses in vivo. In vitro stimulation with LPSs induced Cmtm7^-/- B-1 cell activation, whereas proliferation was marginally reduced. Notably, Cmtm7 deficiency markedly suppressed plasma cell differentiation in response to TLR agonists, accompanied by a decrease in IgM and IL-10 production. At the molecular level, loss of Cmtm7 repressed the downregulation of Pax5 and the upregulation of Xbp1, Irf4, and Prdm1. Furthermore, p38 phosphorylation was inhibited in Cmtm7^-/- B-1 cells. Experiments using a p38 inhibitor revealed that p38 activation was essential for the terminal differentiation of B-1 cells, suggesting that Cmtm7 contributes to B-1 cell differentiation by maintaining p38 activation. Overall, the data reveal the crucial functions of CMTM7 in TLR-induced terminal differentiation and p38 activation in B-1 cells.

CMTM family proteins 1-8: roles in cancer biological processes and potential clinical value

The CKLF-like MARVEL transmembrane domain containing (CMTM) family of genes comprises CKLF and CMTM1–8 (previously called chemokine-like factor superfamily 1–8, CKLFSF1–8). The CMTM family proteins contain a structurally conserved MAL and related proteins for vesicle trafficking and membrane linking (MARVEL) domain. Dysregulated expression of multiple CMTM family members is a common feature in many human cancer types. CMTM proteins control critical biological processes in cancer development, including growth factor receptor activation and recycling, cell proliferation, apoptosis, metastasis, and immune evasion. Emerging in vivo and in vitro evidence indicates that the mechanisms of action of most CMTM proteins are complex and multifactorial. This review highlights new findings regarding the roles of CMTM1–8 in cancer, particularly in tumor growth, metastasis, and immune evasion. Additionally, the potential clinical value of CMTMs as novel drug targets or biomarkers is discussed.

Research Advances in CKLF-like MARVEL Transmembrane Domain-containing Family in Non-small Cell Lung Cancer

CKLF-like MARVEL transmembrane domain-containing member (CMTM) is a new gene family first cloned and reported in 2001. The CMTM family consists of nine members including CKLF and CMTM1-CMTM8, which are located on different chromosomes. Besides exhibiting extensive chemotactic activity, the CMTM family plays an important role in the hematopoiesis system, the immune system, the cardiovascular system and the male reproductive system. Recent in-depth research has also revealed that CMTM is closely associated with the genesis, development and metastasis of tumors, displaying opposing activities in diverse human tumors. In this review, we discuss the structural and functional characteristics of the CMTM family and summarize latest research findings of the relationship between several CMTM members and non-small cell lung cancer.

CMTM4 inhibits cell proliferation and migration via AKT, ERK1/2, and STAT3 pathway in colorectal cancer

CMTM4 (CKLF-like MARVEL transmembrane domain containing 4), a potential tumor suppressor gene, is involved in several types of malignancies. It has been reported to be downregulated and exhibit anti-tumorigenic activities by regulating cell growth and cell cycle in clear cell renal cell carcinoma. It has also been identified as a tumor suppressor in hepatocellular carcinoma (HCC), and its negative expression is a risk factor for poor prognosis of HCC patients. In the present study, an integrated bioinformatics analysis based on The Cancer Genome Atlas (TCGA) database showed that CMTM4 was frequently reduced in colorectal cancer (CRC) and high expression of CMTM4 was associated with increased overall survival rates. Based on these findings, we adopted gain-of-function and lost-of-function strategies using SW480 and HT29 CRC cell lines which have relatively low and high endogenous CMTM4 levels, respectively. We observed impeded cell proliferation and migration upon overexpression of CMTM4 in SW480 cells, and the opposite effects were observed upon knockdown of CMTM4 in HT-29 cells. Cell signaling pathways essential for CRC progression were then examined, and the phosphorylation levels of AKT, ERK1/2, and STAT3 were found to be decreased by CMTM4 overexpression in SW480 cells and elevated by CMTM4 silencing in HT29 cells. Their inhibitors were used to validate that the three signaling pathways contributed to the inhibitory effects of CMTM4 on CRC cells. Taken together, our results suggest that CMTM4 plays a tumor suppressive role in CRC.

Increased CMTM6 can predict the clinical response to PD-1 inhibitors in non-small cell lung cancer patients

CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) plays a crucial role in the stability of the programmed death-ligand 1 (PD-L1). However, there has been no previous study of CMTM6 in non-small cell lung cancer (NSCLC) and its association with PD-L1 has not been confirmed. The aim of this study was to investigate the expression of CMTM6 and PD-L1 and to confirm their predictive roles for anti-PD-1 therapy in non-small cell lung cancer. CMTM6 and PD-L1 immunohistochemical expressions were evaluated in 35 advanced, treatment-refractory NSCLC patients who received PD-1 inhibitor therapy. The correlation between CMTM6 and PD-L1 expression was also determined based on immunohistochemistry and RNA-sequencing data obtained from The Cancer Genome Atlas (TCGA) database. CMTM6 expression was positively correlated with PD-L1 expression in immunohistochemical data (Pearson's r = 0.342 and p = .044). A positive correlation was also identified in the mRNA expression data. Using receiver operating characteristic curves, the levels of CMTM6 and PD-L1 expression which provided the best distinguishing point between responder versus non-responder to PD-1 inhibitors were 70 and 75 H-scores, respectively. The patients in the PD-1 inhibitor responder group had higher CMTM6 expressions in univariate logistic regression analysis (odds ratio (OR) = 5.333, p = .037). However, PD-L1 expression was not associated with response to PD-1 inhibitor (p = .288). In multivariate analysis, CMTM6 was also found to be an independent predictor of the response to PD-1 inhibitors (OR = 6.226, p = .032). CMTM6 expression can be a promising predictor useful for therapeutic decision-making regarding PD-1 inhibitors.

Integrated Analyses of Phenotype and Quantitative Proteome of CMTM4 Deficient Mice Reveal Its Association with Male Fertility

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family that has been implicated in male reproduction. CMTM4 is an evolutionarily conserved member that is highly expressed in the testis. However, its function in male fertility remains unknown. Here, we demonstrate that CMTM4 is associated with spermatogenesis and sperm quality. Using Western blotting and immunohistochemical analyses, we found CMTM4 expression to be decreased in poor-quality human spermatozoa, old human testes, and testicular biopsies with nonobstructive azoospermia. Using CRISPR-Cas9 technology, we knocked out the Cmtm4 gene in mice. These Cmtm4 knockout (KO) mice showed reduced testicular daily sperm production, lower epididymal sperm motility and increased proportion of abnormally backward-curved sperm heads and bent sperm midpieces. These mice also had an evident sub-fertile phenotype, characterized by low pregnancy rates on prolonged breeding with wild type female mice, reduced in vitro fertilization efficiency and a reduced percentage of acrosome reactions. We then performed quantitative proteomic analysis of the testes, where we identified 139 proteins to be downregulated in Cmtm4-KO mice, 100 (71.9%) of which were related to sperm motility and acrosome reaction. The same proteomic analysis was performed on sperm, where we identified 3588 proteins with 409 being differentially regulated in Cmtm4-KO mice. Our enrichment analysis showed that upregulated proteins were enriched with nucleosomal DNA binding functions and the downregulated proteins were enriched with actin binding functions. These findings elucidate the roles of CMTM4 in male fertility and demonstrates its potential as a promising molecular candidate for sperm quality assessment and the diagnosis or treatment of male infertility.

MARVELD1 attenuates arsenic trioxide-induced apoptosis in liver cancer cells by inhibiting reactive oxygen species production

Background

Arsenic trioxide (As₂O₃) is widely used for the treatment of acute promyelocytic leukemia (APL), and more recently, has also been applied to solid tumors. However, there are a fraction of patients with solid tumors, such as liver cancer, who respond to As₂O₃ treatment poorly. The underlying mechanisms for this remain unclear.

Methods

We determined the suitable concentration of drugs by IC50. Cell Counting Kit-8 (CCK-8) and flow cytometry were used to analyze the apoptosis. Morphological changes of the cells were observed by laser scanning confocal microscopy. Furthermore, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by flow cytometry. Quantitative polymerase chain reaction (qPCR) and Western blot tests were conducted to detect the mRNA and protein levels in different groups. Finally, a xenograft tumor assay and histopathological analysis were performed to evaluate the MARVELD1 function in cell proliferation and apoptosis.

Results

Here, we show that MARVELD1 enhances the therapeutic effects of epirubicin, while inducing the strong resistance of liver cancer cells to As₂O₃ treatment. We further demonstrate that the As₂O₃-induced apoptosis was inhibited by MARVELD1 overexpression (24 h Vector vs. MARVELD1 =30.58% vs. 17.41%, P<0.01; 48 h Vector vs. MARVELD1 =46.50% vs. 21.02%, P<0.01), possibly through inhibiting ROS production by enhancing TRXR1 expression. In vivo, we found a significantly increased size (Vector vs. MARVELD1 =203.90±21.92 vs. 675.70±37.84 mm³, P<0.001) and weight (Vector vs. MARVELD1 =0.19±0.02 vs. 0.58±0.05 g, P<0.001) of tumors with high expression of MARVELD1 after As₂O₃ treatment. Consistently, a higher expression of MARVELD1 predicted a poor prognosis for liver cancer patients.

Conclusions

Our data identified a unique role of MARVELD1 in As₂O₃-induced apoptosis and As₂O₃ cancer therapy resistance.

Overexpression of CMTM7 inhibits cell growth and migration in liver cancer

Chemokine-like factor (CKLF)-like, MAL and related proteins for vesicle trafficking and membrane link (MARVEL) transmembrane domain-containing family proteins (CMTMs) have significant roles in the immune system, in male reproduction, as well as in tumorigenesis. Previous studies have shown that CMTM family member 7 (CMTM7) was broadly expressed in various normal tissues, but not in lung, gastric, esophageal, pancreas, and cervix cancers. To explore its relationship with liver cancer, we examined the expression of CMTM7 in liver cancers and its correlation with clinical and pathological conditions. We found that CMTM7 expression was markedly reduced in liver cancer tissues, and negatively correlated with TNM staging and tumor metastasis. In vitro studies showed that enforced expression of CMTM7 inhibited the cell growth and migration of liver cancer cells. Further analysis revealed that CMTM7 suppressed AKT signaling and induced cell cycle arrest at the G0/G1 phase in the liver cancer cells, likely as the consequent of decreased levels of cyclin D1, cyclin-dependent kinase 4 (CDK4), and CDK6, and increased p27 expression. Thus, CMTM7 functions as a tumor suppressor in liver cancer through suppressing cell cycle progression.

C5aR1 regulates migration of suppressive myeloid cells required for costimulatory blockade-induced murine allograft survival

Costimulatory blockade-induced murine cardiac allograft survival requires intragraft accumulation of CD11b⁺ Ly6C^lo Ly6G^- regulatory myeloid cells (Mregs) that expand regulatory T cells (Tregs) and suppress effector T cells (Teffs). We previously showed that C5a receptor (C5aR1) signaling on T cells activates Teffs and inhibits Tregs, but whether and/or how C5aR1 affects Mregs required for transplant survival is unknown. Although BALB/c hearts survived >60 days in anti-CD154 (MR1)-treated or cytotoxic T-lymphocyte associated protein 4 (CTLA4)-Ig-treated wild-type (WT) recipients, they were rejected at ~30 days in MR1-treated or CTLA4-Ig-treated recipients selectively deficient in C5aR1 restricted to myeloid cells (C5ar1^fl/fl xLysM-Cre). This accelerated rejection was associated with ~2-fold more donor-reactive T cells and ~40% less expansion of donor-reactive Tregs. Analysis of graft-infiltrating mononuclear cells on posttransplant day 6 revealed fewer Ly6C^lo monocytes in C5ar1^fl/fl xLysM-Cre recipients. Expression profiling of intragraft Ly6C^lo monocytes showed that C5aR1 deficiency downregulated genes related to migration/locomotion without changes in genes associated with suppressive function. Cotransfer of C5ar1^fl/fl and C5ar1^fl/fl xLysM-Cre myeloid cells into MR1-treated allograft recipients resulted in less accumulation of C5ar1^-/- cells within the allografts, and in vitro assays confirmed that Ly6C^hi myeloid cells migrate to C5a/C5aR1-initiated signals. Together, our results newly link myeloid cell-expressed C5aR1 to intragraft accumulation of myeloid cells required for prolongation of heart transplant survival induced by costimulatory blockade.

EGF Stimulates Rab35 Activation and Gastric Cancer Cell Migration by Regulating DENND1A-Grb2 Complex Formation

Aims: The aim of this study was to reveal the specific molecular mechanisms by which DENND1A accepts EGF signaling and activates Rab35 in gastric cancer.

Methods: The expression of proteins related to DENND1A was examined by western blot analysis. Activation of Rab35 was assessed by GST-pulldown. The interaction of DENND1A and Grb2 was assessed by GST-pulldown and co-immunoprecipitation assays. The relationship between DENND1A and cell migration and invasion was detected using wound healing and transwell by gene overexpression and RNA interference.

Results: EGF stimulation significantly promoted cell migration, whereas transfection with siRab35 partially inhibited EGF-promoted cell migration. DENND1A is also involved in these processes and active Rab35. Moreover, DENND1A binds to the N-terminal and C-terminal SH3 domains of Grb2 through PRD. Of special interest is the observation that EGFR can recruit Grb2-DENND1A complex under EGF stimulation. Further results reveal that the higher the expression of DENND1A, the shorter progression-free survival of gastric cancer patients.

Conclusion: In summary, we confirmed that EGF-Grb2-DENND1A-Rab35 signaling pathway with the interaction of DENND1A and Grb2 as a regulatory center could regulate gastric cancer cell migration and invasion. Ultimately, the expression level of DENND1A predicts the survival status of gastric cancer patients and may become one of the important targets for the treatment of gastric cancer.

The expression of CKLFSF2B is regulated by GATA1 and CREB in the Leydig cells, which modulates testicular steroidogenesis

CKLFSF is a protein family that serves as a functional bridge between chemokines and members of the transmembrane 4 superfamily (TM4SF). In the course of evolution, CKLFSF2 has evolved as two isoforms, namely CKLFSF2A and CKLFSF2B, in mice. CKLFSF2A, also known as CMTM2A and ARR19, is expressed in the testis and is important for testicular steroidogenesis. CKLFSF2B is also known to be highly expressed in the testis. In the prepubertal stage, CKLFSF2B is expressed only in Leydig cells, but it is highly expressed in haploid germ cells and Leydig cells in adult testis. CKLFSF2B is naturally processed inside the cell at its C-terminus to yield smaller proteins compared to its theoretical size of ≈25 kDa. The Cklfsf2b gene is regulated by GATA-1 and CREB protein, binding to their respective binding elements present in the 2-kb upstream promoter sequence. In addition, the overexpression of CKLFSF2B inhibited the activity of the Nur77 promoter, which consequently represses the promoter activity of Nur77-target steroidogenic genes such as P450c17, 3β-HSD, and StAR in MA-10 Leydig cells. Adenovirus-mediated overexpression of CKLFSF2B in primary Leydig cells isolated from adult mice shows a repression of steroidogenic gene expression and consequently testosterone production. Moreover, intratesticular injection of CKLFSF2B-expressing adenovirus in adult mice clearly had a repressive effect compared to the control injected with only GFP-expressing adenovirus. Altogether, these findings suggest that CKLFSF2B might be involved in the development and function of Leydig cells and regulate testicular testosterone production by fine-tuning the expression of steroidogenic genes.