Expression and Clinical Significance of CMTM6 in Nonsmall Cell Lung Cancer

CMTM6 is highly expressed in lung adenocarcinoma and can be used as a biomarker of a poor diagnosis

Background

CMTM6 which is chemokine-like factor (CKLF)-like Marvel transmembrane domain containing family member 6 is involved in the occurrence and progression of various tumors. However, the role of CMTM6 is still unclear in lung adenocarcinoma (LUAD).

Methods

Immunohistochemical, Western blotting and RT‒PCR methods were used to detect the expression of CMTM6 in LUAD. Cox regression and the Kaplan‒Meier method were performed to assess overall survival. Immunogenic features were evaluated according to immune cell infiltrations, immune checkpoints. The sensitivity to chemotherapy agents was estimated using the pRRophetic package.

Results

In LUAD, the expression of CMTM6 was obviously upregulated and was significantly associated with T stage (p = 0.008) and lymph node metastasis (p = 0.018). Multivariate Cox regression analysis demonstrated that CMTM6 was a specialty prognostic risk factor. Based on GSEA enrichment analysis, we found that high expression of CMTM6 is associated with multiple immune signaling pathways. The group with high CMTM6 expression showed a positive association with various types of tumor-infiltrating cells. Moreover, a total of 36 chemotherapeutic drugs were significantly correlated with the expression of CMTM6. Among them, two chemotherapeutic drugs had better therapeutic effects in the high CMTM6 expression group, while 34 chemotherapeutic drugs had therapeutic effects in the low CMTM6 expression group.

Conclusion

This study confirmed that CMTM6 is highly expressed in LUAD and is a new independent poor prognostic factor. In addition, the high expression of CMTM6 is closely related to the tumor microenvironment and immunotherapy, providing new ideas for the treatment of posterior LUAD.

Chemokine-like factor-like MARVEL transmembrane domain containing 6: Bioinformatics and experiments in vitro analyze in glioblastoma multiforme

Introduction

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain containing 6 (CMTM6) is a protein localized to the cell membrane and is known for its ability to co-localize with PD-L1 on the plasma membrane, prevent PD-L1 degradation, and maintain PD-L1 expression on the cell membrane. CMTM6 is highly expressed and plays an important role in various tumors such as oral squamous cell carcinoma (OSCC) and colorectal cancer (CRC), however, its role in Glioblastoma multiforme (GBM) is unclear.

Methods

In this paper, to investigate the role of CMTM6 in GBM, we analyzed the expression of CMTM6 in GBM, the interaction with CMTM6 and the associated genes by bioinformatics. Importantly, we analyzed the expression of CMTM6 in GBM in relation to tumor-infiltrating lymphocytes (TILs), immunoinhibitors, immunostimulators, chemokines and chemokine receptors. We further analyzed the function of CMTM6 and performed in vitro experiments to verify it. Finally, the sensitivity of CMTM6 to drugs was also analyzed and the relationship between CMTM6 and the anticancer drug Piperlonguminine (PL) was verified in vitro.

Results

The results showed that CMTM6 was highly expressed in GBM and correlated with multiple genes. Furthermore, CMTM6 is closely related to the immune microenvironment and inflammatory response in GBM. Bioinformatic analysis of CMTM6 correlated with the function of GBM, and our experiments demonstrated that CMTM6 significantly promoted the migration of GBM cells and epithelial-mesenchymal transition (EMT), but had no significant effect on other functions. Interestingly, we found that in GBM, PL promotes the expression of CMTM6.

Discussion

In this paper, we have performed a detailed analysis and validation of the role of CMTM6 in GBM using bioinformatics analysis and in vitro experiments to demonstrate that CMTM6 may be a potential target for glioma therapy.

High expression of CMTM6 is a risk factor for poor prognosis of gastrointestinal tumors: A meta-analysis

Previous research on the link between CMTM6 expression dysregulation and tumor prognosis has been conflicting. In this study, the predictive effect of CMTM6 in malignant tumors was carefully evaluated using meta-analysis. The literature on the relationship between CMTM6 expression level and malignant tumor prognosis was searched in PubMed, Medline, Embase, and Web of Science databases until April 2021. Data were extracted from eligible studies and analyzed using RevMan5.3 and STATA 12.0 software. The HR and 95%CI were used to analyze the link between CMTM6 expression and OS. And the correlation between CMTM6 expression and clinicopathological features LNM and DM was evaluated by OR and 95%CI. Literature screening eventually included 12 studies involving 2133 patients with malignant tumors. High CMTM6 expression was found to be strongly linked with shorter OS and PFS in cancer patients (HR = 1.84,95%CI: 1.28-2.63, P = 0.001). High CMTM6 expression in gastrointestinal cancers was found to be significantly related with a shorter OS (HR = 2.21, 95%CI: 1.75-2.78, P 0.001). PFS was observed to be related with high CMTM6 expression in cancer patients (HR = 2.029, 95%CI: 1.263-3.26, P = 0.003). Meanwhile, high CMTM6 expression was highly associated to LNM (OR = 1.64, 95%CI: 1.02-2.64, P = 0.043) and DM (OR = 4.07, 95%CI: 1.73-9.56, P = 0.001). However, the expression level of CMTM6 in non-gastrointestinal tumors was not statistically significant with OS or LNM. High CMTM6 expression in gastrointestinal cancers is linked to shorter OS and PFS, as well as LNM and DM, suggesting that high CMTM6 expression could be employed as a new diagnosis for poor prognosis and metastasis.

CMTM6 as a candidate risk gene for cervical cancer: Comprehensive bioinformatics study

Background: CKLF like MARVEL transmembrane domain containing 6 (CMTM6) is an important programmed cell death 1 ligand 1 regulator (PD-L1). CMTM6 was reported as an important regulator of PD-L1 by promoting PD-L1 expression in tumor cells against T cells. However, the function of CMTM6 in cervical cancer is not well characterized. In addition, the role of CMTM6 in the induction of epithelial-mesenchymal transition (EMT) in the context of cervical cancer is unknown. Methods: In this study, we evaluated the role of CMTM6, including gene expression analysis, miRNA target regulation, and methylation characteristic, using multiple bioinformatics tools based on The Cancer Genome Atlas (TCGA) database. The expression of CMTM6 in cervical cancer tissues and non-cancerous adjacent tissues was assessed using immunohistochemistry. In vitro and in vivo function experiments were performed to explore the effects of CMTM6 on growth and metastasis of cervical cancer. Results: Human cervical cancer tissues showed higher expression of CMTM6 than the adjacent non-cancerous tissues. In vitro assays showed that CMTM6 promoted cervical cancer cell invasion, migration, proliferation, and epithelial-mesenchymal transition via activation of mitogen-activated protein kinase (MAPK) c-jun N-terminal kinase (JNK)/p38 signaling pathway. We identified transcription factors (TFs), miRNAs, and immune cells that may interact with CMTM6. Conclusion: These results indicate that CMTM6 is a potential therapeutic target in the context of cervical cancer.

Cigarette Smoke and Morphine Promote Treg Plasticity to Th17 via Enhancing Trained Immunity

CD4+ regulatory T cells (Tregs) respond to environmental cues to permit or suppress inflammation, and atherosclerosis weakens Treg suppression and promotes plasticity. However, the effects of smoking plus morphine (SM + M) on Treg plasticity remain unknown. To determine whether SM + M promotes Treg plasticity to T helper 17 (Th17) cells, we analyzed the RNA sequencing data from SM, M, and SM + M treated Tregs and performed knowledge-based and IPA analysis. We demonstrated that (1) SM + M, M, and SM upregulated the transcripts of cytokines, chemokines, and clusters of differentiation (CDs) and modulated the transcripts of kinases and phosphatases in Tregs; (2) SM + M, M, and SM upregulated the transcripts of immunometabolism genes, trained immunity genes, and histone modification enzymes; (3) SM + M increased the transcripts of Th17 transcription factor (TF) RORC and Tfh factor CXCR5 in Tregs; M increased the transcripts of T helper cell 1 (Th1) TF RUNX3 and Th1-Th9 receptor CXCR3; and SM inhibited Treg TGIF1 transcript; (4) six genes upregulated in SM + M Tregs were matched with the top-ranked Th17 pathogenic genes; and 57, 39 genes upregulated in SM + M Tregs were matched with groups II and group III Th17 pathogenic genes, respectively; (5) SM + M upregulated the transcripts of 70 IPA-TFs, 11 iTregs-specific TFs, and 4 iTregs-Th17 shared TFs; and (6) SM + M, M, and SM downregulated Treg suppression TF Rel (c-Rel); and 35 SM + M downregulated genes were overlapped with Rel-/- Treg downregulated genes. These results provide novel insights on the roles of SM + M in reprogramming Treg transcriptomes and Treg plasticity to Th17 cells and novel targets for future therapeutic interventions involving immunosuppression in atherosclerotic cardiovascular diseases, autoimmune diseases, transplantation, and cancers.

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 inhibits tumor growth and reverses chemoresistance by preventing ubiquitination of p21 in hepatocellular carcinoma

Hepatocellular carcinoma is one of the most common malignancies and has a poor prognosis. The ubiquitin-proteasome pathway is required for the degradation of most short-lived proteins. CMTM6 has been implicated in the progression of various tumors, but its biological function and the underlying molecular mechanisms in HCC are still unknown. In this study, we found that the expression of CMTM6 was significantly reduced in HCC and predicted better prognosis of HCC patients. Through in vitro and in vivo experiments, CMTM6 was shown to inhibit the proliferation of HCC cells by blocking the G1/S phase transition. Mechanistically, CMTM6 interacted with p21 and prevented its ubiquitination mediated by SCFSKP2, CRL4CDT2 and APC/CCDC20 in a cell-cycle–independent manner. As a result, CMTM6 stabilized p21 protein, leading to the inactivation of pRB/E2F pathway. Additionally, CMTM6 sensitized HCC cells to doxorubicin and cisplatin, positively correlated with better clinical outcomes of the transarterial chemoembolization (TACE) treatment for postoperative recurrence. Taken together, our study reports a novel mechanism by which p21 can be stabilized by CMTM6 and pinpoints a crucial role of the CMTM6-p21 axis in suppressing the progression of HCC and sensitizing patients with postoperative recurrence to TACE treatment.

Identification of Novel Lung Cancer Driver Genes Connecting Different Omics Levels With a Heat Diffusion Algorithm

Cancer driver gene is a type of gene with abnormal alterations that initiate or promote tumorigenesis. Driver genes can be used to reveal the fundamental pathological mechanisms of tumorigenesis. These genes may have pathological changes at different omics levels. Thus, identifying cancer driver genes involving two or more omics levels is essential. In this study, a computational investigation was conducted on lung cancer driver genes. Four omics levels, namely, epigenomics, genomics, transcriptomics, and post-transcriptomics, were involved. From the driver genes at each level, the Laplacian heat diffusion algorithm was executed on a protein–protein interaction network for discovering latent driver genes at this level. A following screen procedure was performed to extract essential driver genes, which contained three tests: permutation, association, and function tests, which can exclude false-positive genes and screen essential ones. Finally, the intersection operation was performed to obtain novel driver genes involving two omic levels. The analyses on obtained genes indicated that they were associated with fundamental pathological mechanisms of lung cancer at two corresponding omics levels.

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.