CKLF-like MARVEL Transmembrane Domain Containing 6 Research Articles

CMTM6: A Critical Prognostic Indicator in Non-Small Cell Lung Cancer.

While CKLF-like MARVEL transmembrane domain containing 6 (CMTM6)'s role in stabilizing PD-L1 and immune evasion within tumors is established, its expression in lung cancer tissue and adjacent macrophages remains uncertain. The study aimed to elucidate this ambiguity by investigating CMTM6's role in non-small cell lung cancer (NSCLC) prognosis. Employing immunohistochemical staining on 141 NSCLC and 110 adjacent normal lung tissue samples, CMTM6 expression was evaluated using the HSCORE system. Interestingly, NSCLC exhibited significantly higher CMTM6 levels (161.04±86.60) compared to normal tissues (71.20±45.10) (p < 0.001), detected not only in cancer cells but also in macrophages, lymphocytes, and nearby bronchial epithelial cells. Stratifying patients by CMTM6 levels unveiled a correlation between heightened expression and poorer overall survival (p = 0.003), alongside a link to tumor-infiltrating lymphocytes (TIL) (p = 0.037), especially in cases with increased TIL. Multivariate analysis identified CMTM6 as an independent predictor of overall survival (p = 0.009), implying that elevated CMTM6 expression in NSCLC might signify an adverse prognostic marker for patient outcomes.

Molecular and immunological characteristics of patients with CMTM6 low expression colorectal cancer.

CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), a regulator of programmed cell death ligand 1 (PD-L1), has attracted extensive attention due to its role in tumors. However, research on the expression of CMTM6 in colorectal cancer (CRC) and its relationship with PD-L1 expression and immune cell infiltration is limited. We used The Cancer Genome Atlas database to mine and analyze data from patients with CRC using bioinformatics methods. We investigated the expression of CMTM6 in CRC and its relationship with PD-L1 expression and immune cell infiltration. Immunohistochemistry and PCR were performed to detect CMTM6 and PD-L1 expression in CRC tissues. Differential gene expression analysis was performed using the edgeR package in R and immune cell infiltration analysis was performed using the ssGSEA algorithm. Additionally, GO and KEGG enrichment analyses were conducted to identify the biological processes and pathways associated with low CMTM6 expression. Our study found that CMTM6 expression was significantly upregulated in CRC tissues compared to that in adjacent normal tissues. Patients with high CMTM6 expression exhibited significantly increased levels of PD-L1 expression and higher levels of tumor-infiltrating immune cells compared to patients with low CMTM6 expression. GO and KEGG analyses suggested that CMTM6 may be involved in multiple immune regulatory pathways in CRC.

CMTM6 overexpression confers trastuzumab resistance in HER2-positive breast cancer

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

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.

Expression and Clinical Significance of CMTM6 and PD-L1 in Triple-Negative Breast Cancer

The CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) plays an extremely important role of the programed death receptor ligand-1 (PD-L1) protein. Our study is aimed at investigating the expression of CMTM6 and PD-L1 proteins in triple-negative breast cancer and their correlation with the clinical pathological data of patients. We selected 89 cases of triple-negative breast cancer and 62 cases of normal breast tissue specimens. Immunohistochemical methods were used to detect the expression levels of CMTM6 and PD-L1 and to carefully study differences in their expression. The expression of CMTM6 and PD-L1 in TNBC was higher than that in normal breast tissue, and the expression of the two was positively correlated (p < 0.05). In TNBC, CMTM6 expression is positively correlated with tumor size, lymph node metastasis, Ki67 proliferation index, and TNM stage (p < 0.05). PD-L1 expression is positively correlated with tumor size, lymph node metastasis, Ki67 proliferation index, TNM stage, and vascular infiltration (p < 0.05). Kaplan-Meier analysis showed that the positive expression of CMTM6 and PD-L1 had no correlation with the survival rate of patients (p > 0.05). According to KM-plotter, we found that a higher CMTM6 expression was positively related with relapse-free survival rate of patients (p < 0.05). A higher PD-L1 expression was positively correlated with relapse-free, overall, and distant metastasis survival rate of patients (p < 0.05). In timer database, we found a positive correlation between the expression of CMTM6 and PD-L1 in triple-negative breast cancer. Both CMTM6 and PD-L1 are highly expressed in TNBC, and their expressions are positively related. In the future, the two gene might become targets for the treatment of TNBC, providing a basis of clinical treatment of TNBC.

Oncolytic peptide LTX-315 induces anti-pancreatic cancer immunity by targeting the ATP11B-PD-L1 axis

BackgroundLTX-315 is an oncolytic peptide deriving from bovine lactoferrin, with the ability to induce cancer immunogenic cell death. However, the mechanism used by LTX-315 to trigger the antitumor immune response...

The association between the expression of PD-L1 and CMTM6 in undifferentiated pleomorphic sarcoma.

Undifferentiated pleomorphic sarcoma (UPS) is a sarcoma with a poor prognosis. A clinical trial, SARC028, revealed that treatment with anti-PD-1 drugs was effective against UPS. Studies have reported that UPS expresses PD-L1, sometimes strongly (≥ 50%). However, the mechanism of PD-L1 expression in UPS has remained unclear. CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) was identified as a novel regulator of PD-L1 expression. The positive relationship between PD-L1 and CMTM6 has been reported in several studies. The aim of this study was thus to examine CMTM6 expression in UPS and evaluate the relationship between PD-L1 and CMTM6 in this disease. Fifty-one primary UPS samples were subjected to CMTM6 and PD-L1 immunostaining. CMTM6 expression was assessed using proportion and intensity scores. CMTM6 gene copy number was also evaluated using a real-time PCR-based copy number assay. We also analyzed the mRNA expression and copy number variation of PD-L1 and CMTM6 in The Cancer Genome Atlas (TCGA) data. TCGA data indicated that the mRNAs encoded by genes located around 3p22 were coexpressed with CMTM6 mRNA in UPS. Both proportion and intensity scores of CMTM6 positively correlated with strong PD-L1 expression (≥ 50%) (both p = 0.023). CMTM6 copy number gain increased CMTM6 expression. Patients with UPS with a high CMTM6 intensity score had a worse prognosis for overall survival. UPS showed variation in CMTM6 copy number and CMTM6 expression. CMTM6 expression was significantly correlated with PD-L1 expression, especially with strong PD-L1 expression.

Prognostic Implications of Pan-Cancer CMTM6 Expression and Its Relationship with the Immune Microenvironment.

CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) reportedly stabilizes programmed death-ligand 1 (PD-L1) and enhances the efficacy of immunotherapy. However, correlations between CMTM6 expression and the immune microenvironment and its prognostic value remain unknown in a variety of tumors. CMTM6 expression data were obtained from The Cancer Genome Atlas (TCGA) for 33 cancer types classified into high and low expression subgroups according to the median CMTM6 expression value. Pan-cancer analysis of CMTM6 protein expression in 20 tumor types was performed using a cohort from the Human Protein Atlas (HPA). PD-L1 protein expression data were obtained from The Cancer Proteome Atlas (TCPA) for 32 cancer types. Frequencies of CMTM6 copy number alterations and mutations were analyzed using cBioPortal. MANTIS was employed to estimate microsatellite instability in the TCGA cohort. CIBERSORT and the ESTIMATE algorithm were applied to estimate the relative fractions of infiltrating immune cell types and immune scores, respectively. Kaplan–Meier survival curve analysis was performed to assess the pan-cancer prognostic value of CMTM6.CMTM6 is heterogeneously expressed in diverse cancers. Further, the results revealed low CMTM6 mutation frequencies in multiple cancers. Among them, CMTM6 mutation frequency was the highest in uterine cancer. Additionally, CMTM6 expression was related to PD-L1 protein expression in breast invasive carcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma, cholangiocarcinoma, glioblastoma multiforme (GBM), head and neck squamous cell carcinoma, kidney renal papillary cell carcinoma, sarcoma (SARC), stomach adenocarcinoma, and uterine carcinosarcoma. Increased CMTM6 expression may be associated with increased infiltration of neutrophils in some types of cancer. Finally, pan-cancer analysis indicated that CMTM6 expression was closely related to overall survival in adrenocortical carcinoma, GBM, acute myeloid leukemia, liver hepatocellular carcinoma, mesothelioma, SARC, thymoma, and uveal melanoma. Taken together, these findings highlight that CMTM6 plays an important role in the tumor immune microenvironment, and CMTM6 has been identified to have prognostic value in some types of cancers. Thus, CMTM6 is a potential target for cancer immunotherapy and effective prognostic biomarker.

Impact of CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) expression in gastric cancer.

Background : CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) is the master regulator of programmed cell death-ligand 1 (PD-L1). We aimed to clarify the significance of CMTM6 expression in gastric cancer (GC). Methods : A total of 105 patients who had undergone curative surgical resection for stage II / III GC at Tokushima University Hospital were included in this study. The expression of CMTM6 was examined by immunohistochemistry. Additionally, the relationship of each expression level to several prognostic factors was examined using univariate and multivariate analyses. Results : CMTM6 was not positively correlated with any of the factors examined. The overall survival (OS) rates were significantly poorer in the CMTM6 high-expression group than in the CMTM low-expression group (5-year OS : 57.2% vs. 79.2%, respectively ; p < 0.05). Disease-free survival (DFS) was significantly poorer in the CMTM high-expression group than in the CMTM6 low-expression group (5-year DFS : 52.8% vs. 72.4%, respectively ; p < 0.05). Multivariate analysis confirmed CMTM6 expression as an independent prognostic factor in DFS (p < 0.05). CMTM6 expression tended to be correlated with PD-L1 expression (p = 0.07). Conclusions : CMTM6 is associated with a poor prognosis and immunotolerance through PD-L1 in GC. J. Med. Invest. 68 : 362-367, August, 2021.

CMTM6 Stabilizes PD-L1 Expression and Is a New Prognostic Impact Factor in Hepatocellular Carcinoma.

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

OSCC cell-secreted exosomal CMTM6 induced M2-like macrophages polarization via ERK1/2 signaling pathway.

CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) is a critical regulator of tumor immunology among various cancers. However, the role and underlying molecular mechanism of CMTM6 in oral squamous cell carcinoma (OSCC) progression remains unclear. The expression of CMTM6, PD-L1 and CD163 in OSCC tissues were detected by immunohistochemistry on tissue microarray. The effect of CMTM6 knockdown on OSCC cells and macrophage polarization were analyzed by CCK-8 assay, apoptotic assay, would-healing assay, transwell assay and qPCR. OSCC cell derived exosomes were obtained by ultracentrifugation and the mechanistic studies were conducted by qPCR and Western Blot. 4-Nitroquinoline N-oxide (4NQO) induced OSCC mice were used for verifying the effect of CMTM6 downregulation on M2 macrophage infiltration and tumor growth. In OSCC samples, higher CMTM6 expression has been obviously associated with higher pathological stage of OSCC patients, CD163 + macrophages infiltration and PD-L1 expression. CMTM6 knockdown of OSCC cells inhibited proliferative, migrative and invasive abilities of OSCC cells, as well as inhibited M2 macrophage polarization in vitro with downregulating PD-L1 expression. Importantly, exosomes from OSCC cells shuttled CMTM6 to macrophages and promoted M2-like macrophage polarization through activating ERK1/2 signaling. In addition, in 4NQO-induced OSCC mice, CMTM6 level was positively associated with CD163, CD206 and PD-L1 as well as M2-like macrophage infiltration. OSCC cell-secreted exosomal CMTM6 induces M2-like macrophages polarization to promote malignant progression via ERK1/2 signaling pathway, revealing a novel crosstalk between cancer cells and immune cells in OSCC microenvironment.

Increased Expression of SHMT2 Is Associated With Poor Prognosis and Advanced Pathological Grade in Oral Squamous Cell Carcinoma.

This study focused on the expression of mitochondrial serine hydroxymethyltransferase (SHMT2) in oral squamous cell carcinoma (OSCC) and its correlation with clinical traits and the prognosis of OSCC patients. Immunochemical staining and Western blotting were used to quantify the expression of SHMT2 and related immune markers in OSCC. Using OSCC microarrays and The Cancer Genome Atlas (TCGA) database, we evaluated the association between SHMT2 and various clinical traits. We found that increased expression of SHMT2 was detected in OSCC and correlated with advanced pathological grade and recurrence of OSCC. By a multivariate Cox proportional hazard model, high expression of SHMT2 was shown to indicate a negative prognosis. In addition, in the OSCC microenvironment, increasing the expression of SHMT2 was associated with high expression levels of programmed cell death-ligand 1 (PD-L1), CKLF-like MARVEL transmembrane domain containing 6 (CMTM6), V-type immunoglobulin domain-containing suppressor (VISTA), B7-H4, Slug, and CD317. In the future, more effort will be required to investigate the role of SHMT2 in the OSCC microenvironment.

CMTM6 significantly relates to PD-L1 and predicts the prognosis of gastric cancer patients.

BackgroundThe CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) is a key regulator of the programed death receptor ligand-1 (PD-L1) protein. However, the usefulness of CMTM6 expression as a prognostic indicator and the relationship between CMTM6 and PD-L1 expression in gastric cancer (GC) remains unclear.ObjectivesWe evaluated the expression and prognostic implications of CMTM6 in GC tissue and its relationship with PD-L1 expression.Patients and methodsThe protein expressions of CMTM6 and PD-L1 were detected in 122 cases of postoperative GC tissue using immunohistochemical (IHC) assays. Kaplan–Meier survival analysis was used to calculate the survival probability and a log-rank test was used to compare the survival curves. Univariate and multivariate Cox proportional hazard regression analyses were used to evaluate the clinically-related factors associated with survival. Pearson’s correlation was used to determine the correlation analysis and estimate the statistical significance. The univariate and multivariate logistic regression analyses were used to analyze the relationship between clinically-related factors and PD-L1 expression.ResultsKaplan–Meier survival analysis showed that patients with high CMTM6 expression had shorter overall survival (OS) than those with low expression (P < 0.001). The expression of CMTM6 was an independent risk factor for prognosis in multivariate Cox proportional hazard regression analyses (HR:2.221, CI% [1.36–3.628], P = 0.001). The OS of patients with positively expressed PD-L1 was significantly shorter than those with negatively expressed PD-L1 (P = 0.003). The expression of CMTM6 was significantly related to the positive expression of PD-L1 in gastric cancer tissues (r = 0.186, P = 0.041). The expression of CMTM6 was the independent risk factor for PD-L1 expression in multivariate logistic regression analysis (OR:2.538, CI% [1.128–5.714], P = 0.024).ConclusionCMTM6 expression is significantly related to PD-L1 and may be a useful prognostic indicator and a specific therapeutic target for cancer immunotherapy for GC patients.

CMTM6, the newly identified PD-L1 regulator, correlates with PD-L1 expression in lung cancers

Modulation of Immune check point regulators, especially the PD-1/PD-L1 axis, plays a critical role in successful management of a small proportion of lung cancer patients, but not so effective in the rest of lung cancer patients. A better understanding of immunotherapy non-responsive or resistant patients therefore warranted for future development of novel therapeutics. The newly identified regulator CMTM6 (CKLF-like MARVEL transmembrane domain containing 6) has been reported to serves as the stabilizer of PD-L1 and enhances the inhibitory effect of PD-L1 on immune system in both cell line and animal models, but its clinical relevance associated with PD-L1 is unknown and the current study is designed to address this question. The study using immunohistochemistry demonstrated that CMTM6 positivity from 15 out of 19 types of cancers with our in-house tissue microarray, and PD-L1 expression is always found only in CMTM6 positive cancers. CMTM6 and PD-L1 expression were analyzed in 81 lung cancer patient sample, and we observed that CMTM6 expression correlated with cancer histotypes and inversely correlated with cancer metastases, but not with patients’ age and gender. No PD-L1 expression was observed in negative CMTM6 samples. Higher expression PD-L1 is also associated with higher CMTM6 expression. In summary, CMTM6 expression is associated with PD-L1 expression, as well as lung cancer histotypes and metastasis. The results thus for the first time confirmed earlier reports on CMTM6/PD-L1 connection, from a clinical aspect of analysis.