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

Potential drug targets for tumors identified through Mendelian randomization analysis

According to the latest cancer research data, there are a significant number of new cancer cases and a substantial mortality rate each year. Although a substantial number of clinical patients are treated with existing cancer drugs each year, the efficacy is unsatisfactory. The incidence is still high and the effectiveness of most cancer drugs remains unsatisfactory. Therefore, we evaluated the human proteins for their causal relationship to for cancer risk and therefore also their potential as drug targets. We used summary tumors data from the FinnGen and cis protein quantitative trait loci (cis-pQTL) data from a genome-wide association study, and employed Mendelian randomization (MR) to explore the association between potential drug targets and nine tumors, including breast, colorectal, lung, liver, bladder, prostate, kidney, head and neck, pancreatic caners. Furthermore, we conducted MR analysis on external cohort. Moreover, Bidirectional MR, Steiger filtering, and colocalization were employed to validate the main results. The DrugBank database was used to discover potential drugs of tumors. Under the threshold of False discovery rate (FDR) < 0.05, results showed that S100A16 was protective protein and S100A14 was risk protein for human epidermal growth factor receptor 2-positive (HER-positive) breast cancer, phosphodiesterase 5A (PDE5A) was risk protein for colorectal cancer, and melanoma inhibitory activity (MIA) was protective protein for non-small cell lung carcinoma (NSCLC). And there was no reverse causal association between them. Colocalization analysis showed that S100A14 (PP.H4.abf = 0.920) and S100A16 (PP.H4.abf = 0.932) shared causal variation with HER-positive breast cancer, and PDE5A (PP.H4.abf = 0.857) shared causal variation with colorectal cancer (CRC). The MR results of all pQTL of PDE5A and MIA were consistent with main results. In addition, the MR results of MIA and external outcome cohort were consistent with main results. In this study, genetic predictions indicate that circulating S100 calcium binding protein A14 (S100A14) and S100 calcium binding protein A16 (S100A16) are associated with increase and decrease in the risk of HER-positive breast cancer, respectively. Circulating PDE5A is associated with increased risk of CRC, while circulating MIA is associated with decreased risk of NSCLC. These findings suggest that four proteins may serve as biomarkers for cancer prevention and as potential drug targets that could be expected for approval.

Bioinformatics analysis of CMTM family in pan-cancer and preliminary exploration of CMTM6 in bladder cancer

BACKGROUND

The chemokine-like factor (CKLF)-like Marvel transmembrane structural domain (CMTM) family is widely expressed in the tumor and immune systems and is essential in human cancer progression. However, the multi-omic profile of CMTM family genes and their role in tumor patient prognosis and immune microenvironment have not been explored.

METHODS

We collected data from 33 cancers and 33 non-cancers and then comprehensively analyzed the basal expression levels of CMTM family genes in normal human tissues as well as abnormal expression in diseases, genomic alterations, diagnostic and prognostic roles, subcellular localization, pathway enrichment, the immune microenvironment, associations with immune checkpoints, and drug sensitivities as well as to predict the immunotherapeutic response of patients to ICIs and targeting of small molecule drugs, the above results were validated by immunohistochemical staining, pathology sections and experiments. We also performed protein docking of immune checkpoints binding to CMTM6 and screening of small molecule drugs targeting CMTM6 based on mass spectrometry results and molecular docking techniques. Finally, we experimentally confirmed the role of CMTM6 in bladder cancer.

RESULTS

We found differential expression and diagnostic biomarker value of the CMTMs family in diseases (cancer and non-cancer). CMTMs were also found to play a key role in pan-cancer with the tumor microenvironment. CMTMs were closely associated with common immune checkpoints, TMB and MSI, so we scored CMTMs based on CMTMs expression in patients undergoing ICI, and patients with lower scores had better survival and showed higher immunotherapy response after immunotherapy. Finally, molecular docking was used to identify small molecule inhibitors that could target CMTM6 and binding poses of CMTM6 to other immune checkpoint genes. Finally, it was determined experimentally that knockdown of CMTM6 gene expression inhibited the proliferation and invasion of bladder cancer cells.

CONCLUSIONS

Our findings provide a valuable strategy to guide the diagnostic and therapeutic direction of CMTM family genes in disease.

Prognostic significance of RKIP, TGM2, and CMTM4 expression in oral squamous cell carcinoma

BACKGROUND

The expression of RKIP, TGM2, and CMTM4 in oral squamous cell carcinoma (OSCC) and normal oral tissues was detected and their correlations were analyzed. The relationships between RKIP, TGM2, and CMTM4 and the clinicopathological parameters and prognosis of patients were analyzed.

METHODS

Seventy cancerous and adjacent normal tissue samples were selected, recorded in the pathology department, and embedded in paraffin. Protein expression was detected by immunohistochemistry. Statistical software (SPSS 25.0, IBM Corporation) was used for the statistical analysis. The chi-squared (χ2) test was used to analyze the expression of RKIP, TGM2, and CMTM4 proteins and their clinicopathological features. Differences in RKIP, TGM2, and CMTM4 protein levels between OSCC and normal tissues were compared using a χ2 test. Survival analysis was performed using the Kaplan-Meier method, and differences between survival curves were determined using the log-rank test. The effects of RKIP, TGM2, and CMTM4 expression on patient prognosis were analyzed using a multivariate Cox proportional hazards regression model. P < .05 was considered statistically significant.

RESULTS

The expression level of RKIP correlated with age and clinical stage (P < .05). TGM2 was associated with clinical stage and lymph node metastasis (P < .05). The expression of CMTM4 increased with a decrease in cancer differentiation. Kaplan-Meier survival analysis suggested that the positive expression of TGM2 and CMTM4 may predict poor prognosis in patients with OSCC. The multivariate Cox proportional hazards regression model suggested that TGM2 could be an independent prognostic factor for patients with OSCC.

CONCLUSION

Combined expression of TGM2 and CMTM4 can be used as an indicator to evaluate the risk of metastasis and prognosis of OSCC.

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.

Transmembrane Protein CMTM6 Alleviates Ocular Inflammatory Response and Improves Corneal Epithelial Barrier Function in Experimental Dry Eye

Purpose

To investigate the impact of transmembrane protein CMTM6 on the pathogenesis of dry eye disease (DED) and elucidate its potential mechanisms.

Methods

CMTM6 expression was confirmed by database analysis, real-time polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry. Tear secretion was measured using the phenol red thread test. Immune cell infiltration was assessed through flow cytometry. Barrier function was evaluated by fluorescein sodium staining, immunofluorescence staining of zonula occludens 1 (ZO-1), and electric cell-substrate impedance sensing (ECIS) assessment. For silencing CMTM6 expression, siRNA and shRNA were employed, along with lentiviral vector-mediated overexpression of CMTM6. Proinflammatory cytokine levels were analyzed by RT-PCR and cytometric bead array (CBA) analysis.

Results

CMTM6 showed high expression in healthy human and mouse corneal and conjunctival epithelium but was notably reduced in DED. Notably, this downregulation was correlated with disease severity. Cmtm6-/- dry eye (DE) mice displayed reduced tear secretion, severe corneal epithelial defects, decreased conjunctival goblet cell density, and upregulated inflammatory response. Additionally, Cmtm6-/- DE mice and CMTM6 knockdown human corneal epithelial cell-transformed (HCE-T) cells showed more severe barrier disruption and reduced expression of ZO-1. Knockdown of CMTM6 in HCE-T cells increased inflammatory responses induced by hyperosmotic stress, which was significantly mitigated by CMTM6 overexpression. Moreover, the level of phospho-p65 in hyperosmolarity-stimulated HCE-T cells increased after silencing CMTM6. Nuclear factor kappa B (NF-κB) p65 inhibition (JSH-23) reversed the excessive inflammatory responses caused by hyperosmolarity in CMTM6 knockdown HCE-T cells.

Conclusions

The reduction in CMTM6 expression on the ocular surface contributes to the pathogenesis of DED. The CMTM6-NF-κB p65 signaling pathway may serve as a promising therapeutic target for DED.

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.

Genetic alterations in juvenile cervical clear cell adenocarcinoma unrelated to human papillomavirus

Clear cell adenocarcinoma of the cervix (CCAC) is a special type of HPV-independent cervical cancer. It has a low incidence rate, can be difficult to diagnose early, has a poor prognosis. Its peak incidence is in adolescence, which poses a great threat to women's health. Therefore, it is very important to explore the pathogenesis of cervical clear cell adenocarcinoma to guide subsequent treatment and prevention. This study analyzed 3 juvenile patients with CCAC diagnosed at the First Affiliated Hospital of Zhengzhou University. Using next-generation sequencing methods, we analyzed the pathogenesis of the patients and their close relatives by analyzing the genetic alterations of patients. CMTM5 was identified as the only shared mutated gene. Using published literature and comparative analyses of related disease-causing genes, 6 of the 19 genes (ALKBH7, MYCBP, MZF1, RNF207, RRS1, and TUSC2) were screened as genes with mutations in patients and had higher mutation rates in reproductive cancers. Pathway analysis showed that downregulated genes in non-HPV cervical cancer were mainly related to the immune system response, suggesting that non-HPV cervical cancer differs from HPV-infected cervical cancer in that the immune response is weaker, which is consistent with the weak correlation with viral infection.

Molecular mechanism of VE-cadherin in regulating endothelial cell behaviour during angiogenesis

Vascular endothelial (VE)-cadherin, an endothelium-specific adhesion protein, is found in the junctions between endothelial cells (ECs). It's crucial to maintain the homogeneity of ECs. Keeping and controlling the contact between ECs is essential. In addition to its adhesive function, VE-cadherin plays important roles in vascular development, permeability, and tumour angiogenesis. Signal transfer, cytoskeletal reconstruction, and contractile integrating, which are crucial for constructing and maintaining monolayer integrity as well as for repair and regeneration, are the foundation of endothelial cell (EC) junctional dynamics. The molecular basis of adhesion junctions (AJs), which are closely related and work with actin filaments, is provided by the VE-cadherin-catenin complex. They can activate intracellular signals that drive ECs to react or communicate structural changes to junctions. An increasing number of molecules, including the vascular endothelial growth factor receptor 2 (VEGFR2) and vascular endothelial protein tyrosine phosphatase (VE-PTP), have been connected to VE-cadherin in addition to the conventional VE-cadherin-catenin complex. This review demonstrates significant progress in our understanding of the molecular mechanisms that affect VE-cadherin's function in the regulation of EC behaviour during angiogenesis. The knowledge of the molecular processes that control VE-cadherin's role in the regulation of EC behaviour during angiogenesis has recently advanced, as shown in this review.

Directed growth and fusion of membrane-wall microdomains requires CASP-mediated inhibition and displacement of secretory foci

Casparian strips (CS) are aligned bands of lignin-impregnated cell walls, building an extracellular diffusion barrier in roots. Their structure profoundly differs from tight junctions (TJ), analogous structures in animals. Nonetheless, CS membrane domain (CSD) proteins 1-5 (CASP1-5) are homologues of occludins, TJ components. CASP-marked membranes display cell wall (matrix) adhesion and membrane protein exclusion. A full CASP knock-out now reveals CASPs are not needed for localized lignification, since correctly positioned lignin microdomains still form in the mutant. Ultra-structurally, however, these microdomains are disorganized, showing excessive cell wall growth, lack of exclusion zone and matrix adhesion, and impaired exocyst dynamics. Proximity-labelling identifies a Rab-GTPase subfamily, known exocyst activators, as potential CASP-interactors and demonstrate their localization and function at the CSD. We propose that CASP microdomains displace initial secretory foci by excluding vesicle tethering factors, thereby ensuring rapid fusion of microdomains into a membrane-cell wall band that seals the extracellular space.

CKLF as a Prognostic Biomarker and Its Association with Immune Infiltration in Hepatocellular Carcinoma

The Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing (CMTM) family, comprising nine members, is involved in the tumorigenesis and progression of various cancers. However, the expression profiles and clinical significance of CMTM family members in hepatocellular carcinoma (HCC) are not fully clarified. In this study, the RNA-sequencing and clinical data were downloaded from The Cancer Genome Atlas (TCGA) databases. The Kaplan–Meier method and the Cox proportional hazards regression analysis were used to evaluate the prognostic significance of CMTM family members. Single-sample gene set enrichment analysis (ssGSEA) and ESTIMATE algorithms were employed to explore the relationship between CMTM family genes and the tumor microenvironment in HCC. Finally, the prognostic CMTM family gene expression was further validated by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical (IHC) staining in clinical HCC tissue specimens. The results indicated that, compared with normal tissues, the expression of CKLF, CMTM1, CMTM3, CMTM4, CMTM7, and CMTM8 were significantly upregulated in HCC, while the expression of CMTM2, CMTM5, and CMTM6 were significantly downregulated in HCC. Univariate and multivariate Cox regression analysis demonstrated that CKLF was an independent prognostic biomarker for the overall survival (OS) of HCC patients. In HCC, the expression of CKLF was found to be correlated with immune cell infiltration, immune-related functions, and immune checkpoint genes. The qRT-PCR and IHC confirmed that CKLF was highly expressed in HCC. Overall, this research suggested that CKLF is involved in immune cell infiltration and may serve as a critical prognostic biomarker, which provides new light on the therapeutics for HCC.

MARVEL domain containing CMTM4 affects CXCR4 trafficking

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.

Bidirectional crosstalk between epithelial-mesenchymal plasticity and IFNγ-induced PD-L1 expression promotes tumour progression

Epithelial-mesenchymal transition (EMT) and immunoevasion through upregulation of programmed death-ligand 1 (PD-L1) are important drivers of cancer progression. While EMT has been proposed to facilitate PD-L1-mediated immunosuppression, molecular mechanisms of their interaction remain obscure. Here, we provide insight into these mechanisms by proposing a mathematical model that describes the crosstalk between EMT and interferon gamma (IFNγ)-induced PD-L1 expression. Our model shows that via interaction with microRNA-200 (miR-200), the multi-stability of the EMT regulatory circuit is mirrored in PD-L1 levels, which are further amplified by IFNγ stimulation. This IFNγ-mediated effect is most prominent for cells in a fully mesenchymal state and less strong for those in an epithelial or partially mesenchymal state. In addition, bidirectional crosstalk between miR-200 and PD-L1 implies that IFNγ stimulation allows cells to undergo EMT for lower amounts of inducing signal, and the presence of IFNγ accelerates EMT and decelerates mesenchymal-epithelial transition (MET). Overall, our model agrees with published findings and provides insight into possible mechanisms behind EMT-mediated immune evasion, and primary, adaptive, or acquired resistance to immunotherapy. Our model can be used as a starting point to explore additional crosstalk mechanisms, as an improved understanding of these mechanisms is indispensable for developing better diagnostic and therapeutic options for cancer patients.

Identification of prognostic biomarkers in the CMTM family genes of human ovarian cancer through bioinformatics analysis and experimental verification

Background: Ovarian cancer (OV) is one of the most common gynecological malignancies worldwide, and its immunotherapy has considerable prospects. Multiple members of the CMTM family were aberrantly expressed in human cancers and controlled key malignant biological processes and immune regulation in cancer development. However, little is known about the function of this gene family in ovarian cancer, especially in terms of immunity.

Methods: GEPIA, Oncomine, HPA, Kaplan–Meier plotter, cBioPortal, GeneMANIA, and TIMER were used to analyze the differential gene expression, prognostic value, genetic alterations, and alterations in the immune microenvironment of the CMTM family in patients with ovarian cancer. Importantly, RT-qPCR was used to verify the gene expression of the CMTM family.

Results: CMTM1/3/4/6/7/8 showed abnormally high expression at the mRNA and protein levels in OV tissues based on the GEPIA and HPA databases. RT-qPCR showed that CMTM1/6/8 was highly expressed in ovarian cancer cell lines. IHC verified that CMTM8 is highly expressed in ovarian cancer tissues and is closely related to Ki-67. Survival analysis showed that high expression of CMTM1/2/3/5/8 can lead to a significant reduction in overall survival and progression-free survival. There were many types of genetic alterations in the CMTM family. Also, CMTM1/2/3/6 had a certain correlation with the changes in the immune microenvironment such as immune cell infiltration and immune checkpoint expression, which may be the potential mechanism of the CMTM family in ovarian cancer. IHC verified that CMTM6 is highly expressed in ovarian cancer tissues and is closely related to PD-L1.

Conclusion: This study confirmed that the CMTM family has abnormal expression in ovarian cancer and CMTM8 can be used as a biomarker for prognostic evaluation. Also, the CMTM family may be used as a potential target for immunotherapy based on the suppression of immune checkpoints.

Prognostic significance and immune characteristics of CMTM4 in hepatocellular carcinoma

Background

Previous study has shown that chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family member 4 (CMTM4) can bind and maintain programmed cell death ligand 1 (PD-L1) expression to promote tumor progression by alleviating the suppression of tumor-specific T cell activity, suggesting its potential role in tumor immunotherapy. However, the role of CMTM4 in tumor immunity has not been well clarified, especially in hepatocellular carcinoma (HCC).

Methods

The protein expression of CMTM4/PD-L1/CD4/CD8 was detected by immunohistochemistry (IHC) detection in 90 cases of HCC tissues. The mRNA expression profiles and related prognosis data were obtained from The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC). Two immune therapy cohorts were from Imvigor210 and GSE176307.

Results

Though the single protein expression of CMTM4, PD-L1, CD4 or CD8 in HCC tissues by IHC detection didn’t show a significant relationship with the prognosis of HCC patients, we found that high co-expression of CMTM4/PD-L1/CD4 showed a good prognosis of HCC patients. Further Timer 2.0 analysis identified that HCC patients with high expression of CMTM4/PD-L1 and high infiltration of CD4⁺ T cells had a better overall survival than those with low infiltration of CD4⁺ T cells. Moreover, a series of bioinformatics analyses revealed that CMTM4-related genes posed important effects on prognosis and immunity in HCC patients, and CMTM4 had a positive correlation with infiltration of CD4⁺ and CD8⁺ T cells in HCC. At last, we used two immunotherapy cohorts to verify that the combination of CMTM4 with PD-L1 could improve the prognosis of tumor patients underwent immunotherapy.

Conclusions

CMTM4 and PD-L1 co-expression with T cell infiltration shows prognostic significance in HCC, suggesting combined effect from multiple proteins should be considered in HCC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09999-y.

Identification of biomarkers related to neutrophils and two molecular subtypes of systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE), an autoimmune disease with complex pathogenesis, poses a considerable threat to women’s health. Increasing evidence indicates that neutrophils play an important role in the development and progression of lupus.

Methods

Weighted correlation network analysis and single-sample gene set enrichment analysis (GSEA) were used to analyse SLE expression data from a comprehensive gene expression database and identify modules associated with neutrophils. Thereafter, the biomarkers most closely related to neutrophils were identified. We reclassified SLE into two molecular subtypes based on the aforementioned biomarkers and evaluated cell infiltration, molecular mechanisms, and signature pathways in each subtype.

Results

The results showed significant differences in immunological characteristics between the two molecular subtypes of SLE. Hub genes were significantly upregulated in the NEUT-H subtype, and they may be associated with lupus activity. The GSEA revealed associations between our biomarkers and key metabolic pathways.

Conclusions

Our study provides not only a classification for patients with SLE but also new cell and gene targets for immunotherapy, as well as a new experimental paradigm to explore immunotherapy for other autoimmune diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01306-9.

Cancer mutation profiles predict ICIs efficacy in patients with non-small cell lung cancer

Although immune checkpoint inhibitors (ICIs) have produced remarkable responses in non-small cell lung cancer (NSCLC) patients, receivers still have a relatively low response rate. Initial response assessment by conventional imaging and evaluation criteria is often unable to identify whether patients can achieve durable clinical benefit from ICIs. Overall, there are sparse effective biomarkers identified to screen NSCLC patients responding to this therapy. A lot of studies have reported that patients with specific gene mutations may benefit from or resist to immunotherapy. However, the single gene mutation may be not effective enough to predict the benefit from immunotherapy for patients. With the advancement in sequencing technology, further studies indicate that many mutations often co-occur and suggest a drastic transformation of tumour microenvironment phenotype. Moreover, co-mutation events have been reported to synergise to activate or suppress signalling pathways of anti-tumour immune response, which also indicates a potential target for combining intervention. Thus, the different mutation profile (especially co-mutation) of patients may be an important concern for predicting or promoting the efficacy of ICIs. However, there is a lack of comprehensive knowledge of this field until now. Therefore, in this study, we reviewed and elaborated the value of cancer mutation profile in predicting the efficacy of immunotherapy and analysed the underlying mechanisms, to provide an alternative way for screening dominant groups, and thereby, optimising individualised therapy for NSCLC patients.

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.

CMTM6 as a master regulator of PD-L1

Immune checkpoint proteins, such as programmed cell death receptor 1 (PD-1) and its ligand (PD-L1), play critical roles in the pathology of chronic inflammatory pathological conditions, particularly cancer. In addition, the activation of PD-1/PD-L1 pathway is involved in mediating resistance to certain anti-cancer chemo- and immuno-therapeutics. Unfortunately, targeting the PD-1/PD-L1 pathway by the available anti-PD-1/PD-L1 drugs can benefit only a small proportion of cancer patients. Thus, studying the factors that regulate the expression of these immune checkpoint proteins is of central importance in this context. Recent investigations have identified CMTM6 and, to a lesser extent, CMTM4, as master regulators of PD-L1 expression in various cancer cells. Understanding the mechanisms by which such proteins upregulate the expression of PD-L1 in tumor cells, and determining the potential regulators of CMTM6 expression in different types of cancers will accelerate the development of new therapeutic targets and/or lead to the enhancement of the currently available PD-1/PD-L1 blockade therapies.

CMTM Family Genes Affect Prognosis and Modulate Immunocytes Infiltration in Grade II/III Glioma Patients by Influencing the Tumor Immune Landscape and Activating Associated Immunosuppressing Pathways

Lower-grade glioma (LGG) is one of the most common primary tumor types in adults. The chemokine-like factor (CKLF)-like Marvel transmembrane domain-containing (CMTM) family is widely expressed in the immune system and can modulate tumor progression. However, the role of the CMTM family in LGG remains unknown. A total of 508 LGG patients from The Cancer Genome Atlas (TCGA) database were used as a training cohort, and 155 LGG patients from the Chinese Glioma Genome Atlas (CGGA) array database, 142 LGG patients from the CGGA RNA-sequencing database, and 168 LGG patients from the GSE108474 database were used as the validation cohorts. Patients were subdivided into two groups using consensus clustering. The ENET algorithm was applied to build a scoring model based on the cluster model. Finally, ESTIMATE, CIBERSORT, and xCell algorithms were performed to define the tumor immune landscape. The expression levels of the CMTM family genes were associated with glioma grades and isocitrate dehydrogenase (IDH) status. Patients in cluster 2 and the high-risk score group exhibited a poor prognosis and were enriched with higher grade, wild-type IDH (IDH-WT), 1p19q non-codeletion, MGMT promoter unmethylation, and IDH-WT subtype. Patients in cluster 1 and low-risk score group were associated with high tumor purity and reduced immune cell infiltration. Enrichment pathways analysis indicated that several essential pathways involved in tumor progression were associated with the expression of CMTM family genes. Importantly, PD-1, PD-L1, and PD-L2 expression levels were increased in cluster 2 and high-risk groups. Therefore, the CMTM family contributes to LGG progression through modulating tumor immune landscape.

CMTM6, a potential immunotherapy target

The CKLF-like MARVEL transmembrane domain-containing protein 6 (CMTM6), which binds to the programmed death ligand 1 (PD-L1) and stabilizes the expression of PD-L1 on the cell surface, has been recently discovered as a novel regulator of PD-L1 expression in cancer. PD-L1 is an immune checkpoint inhibitory molecule that can mediate the immune escape of tumor cells in various tumors and has been studied intensively in recent years. In 2017, two articles simultaneously reported that CMTM6 can stabilize the expression of PD-L1 on the plasma membrane and prevent PD-L1 from being degraded by lysosomes; therefore, CMTM6 may play an important role in tumor cell immune escape and immunosuppression. At present, there are few studies on the relationship between the expression of CMTM6 and PD-L1 in different tumors and diseases. These studies together suggested that CMTM6 may be a potential novel immunotherapy target. In this review, we briefly describe the latest research progresses of CMTM6 in various cancers and other diseases.

LncRNA SNHG12 promotes the development and progression of colon cancer by regulating the miR-15a/PDK4 axis

Colon cancer is a common gastrointestinal tumor with complex pathological process. Recently, the relationship between long non-coding RNA (lncRNA) and colon cancer has attracted more and more attention, whereas the underlying molecular mechanism is still poorly understood. Here, we found that the expression of lncRNA small nucleolar RNA host gene 12 (SNHG12) was markedly upregulated in colon cancer samples compared to normal adjacent tissues. Notably, patients with low expression of SNHG12 displayed higher survival rate than those with high expression of SNHG12. Further researches revealed that knockdown of SNHG12 suppressed the malignant phenotype of colon cancer cells. Interestingly, SNHG12 could function as a sponge to specifically bind to microRNA-15a (miR-15a). Moreover, we confirmed that pyruvate dehydrogenase kinase 4 (PDK4) is a direct target gene of miR-15a. Finally, inhibiting miR-15a expression largely abolished the effect of SNHG12 silencing on colon cancer cells. In conclusion, our data uncovered the critical role of SNHG12 in the development and progression of colon cancer through regulating the miR-15a/PDK4 axis, therefore providing a promising target for treating this disease.

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.

CMTM3 Overexpression Predicts Poor Survival and Promotes Proliferation and Migration in Pancreatic Cancer

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-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.