Search

Melanoma-associated Ag (MAGE)-C2, an immunogenic cancer germline (testis) Ag, is highly expressed by various tumor cells, thymic medullary epithelial cells, and germ cells. In this study, we aimed to explore the immunologic properties of MAGE-C2–specific CD8+ T cells and the relationship of its TCR β-chain V region (TCR vβ) subfamily distribution to prognosis of patients with esophageal cancer. PBMCs and tumor-infiltrating lymphocytes expanded by CD3/CD28 Dynabeads and MAGE-C2 peptides in vitro resulted in the induction of lysosome-associated membrane protein-1 (LAMP-1 or CD107a) on the cell surface and the production of IFN-γ by MAGE-C2–specific CD8+ T cells. We found differential TCR vβ subfamily distribution among flow-sorted CD107a+IFN-γ+ and CD107a−IFN-γ− CD8+ T cells. The proportion of CD107a+ and/or IFN-γ+ tetramer+ CD8+ T cells was lower in patients with lymph node metastasis, late tumor stage, and poorly differentiated state (p < 0.05). T-box transcription factor was positively correlated with CD107a and IFN-γ. Kaplan–Meier analysis showed that patients whose MAGE-C2–specific CD8+ T cells expressed high CD107a and/or IFN-γ had a longer survival time when compared with patients whose MAGE-C2–specific CD8+ T cells expressed low levels of CD107a and/or IFN-γ. Moreover, analysis of TCR vβ subfamily distribution revealed that a higher frequency of TCR vβ16 in MAGE-C2–specific CD8+ T cells was positively correlated with a better prognosis. These results suggest that the presence of functional MAGE-C2–specific CD8+ T cells had an independent prognostic impact on the survival of patients with esophageal cancer.

TGF-b,secreted by MDSCs,could regulate MAEL through Smad2/Smad3.

Primer sequences were used in our study.

Maelstrom (MAEL) is a novel cancer/testis-associated gene, which is not only expressed in the male testicular germ cells among human normal tissues, but is also aberrantly expressed in various cancer tissues. In our study, MAEL was characterized as a tumor-promoting gene and was significantly associated with esophageal squamous cell carcinoma (ESCC) recurrence and unfavorable prognosis. Kaplan–Meier analysis showed that patients with high MAEL expression had a shorter survival time. Functional experiments showed that MAEL promoted tumor cell growth and inhibited cell apoptosis. These results prompted us to investigate the factors affecting the tumorigenicity of MAEL. Further experimentation demonstrated that MAEL enhanced the expression of phosphorylated Akt1, with subsequent phosphorylation of nuclear factor kappa B (NF-κB) subunit RelA in tumor cells, and chemoattracted myeloid-derived suppressor cells (MDSCs) by upregulating interleukin-8 (IL8) to accelerate tumor progression in the tumor microenvironment. We also found that TGFβ secreted by MDSCs could upregulate MAEL by inducing Smad2/Smad3 phosphorylation. In summary, this study revealed a mechanism by which MAEL could upregulate IL8 through Akt1/RelA to direct MDSCs homing into the tumor, suggesting that MAEL could be an attractive therapeutic target and a prognostic marker against ESCC. Cancer Immunol Res; 6(10); 1246–59. ©2018 AACR.

Therapies targeting programmed cell death protein 1 (PD-1) have gained great success in patients with multiple types of cancer. The regulatory mechanisms underlying PD-1 expression have been extensively explored. However, the impact of long noncoding RNAs on PD-1 expression remains elusive. In this study, we identified the Notch1/lncNDEPD1 axis, which plays a critical role in PD-1 expression in human CD8+ T cells. RNA sequencing and quantitative reverse transcription PCR data showed that lncNDEPD1 was upregulated in activated T cells, especially in PD-1high subsets. Fluorescence in situ hybridization demonstrated that lncNDEPD1 was localized in the cytoplasm. A mechanistic study showed that lncNDEPD1 could bind with miR-3619-5p and PDCD1 mRNA to prevent PDCD1 mRNA degradation and then upregulate PD-1 expression. A chromatin immunoprecipitation assay showed that Notch1 directly binds to the promoter of lncNDEPD1 instead of PDCD1. Furthermore, chimeric Ag receptor T cells expressing lncNDEPD1-specific short hairpin RNAs were generated. Chimeric Ag receptor T cells with decreased lncNDEPD1 expression showed enhanced tumoricidal effects when PD-L1 was present. Our work uncovered a new regulatory mechanism of PD-1 expression and thus provided a potential target to decrease PD-1 without affecting T cell function.

Drug resistance remains the major obstacle limiting the effectiveness of chemotherapy for esophageal squamous cell carcinoma (ESCC)[1]. However, how stromal cells cooperate with immune cells to contribute to drug resistance is not yet fully understood. In this study, we observed that monocytic myeloid-derived suppressor cells (M-MDSCs) were correlated with cisplatin resistance in patients with ESCC. Furthermore, CAFs promoted differentiation of monocytes into M-MDSCs phenotypically and functionally in vitro. Mechanically, both interleukin (IL)-6 and exosome-packed microRNA-21 (miR-21) secreted by CAFs synergistically promoted the generation of M-MDSCs via activating the signal transducing activator of transcription 3 (STAT3) by IL-6 in an autocrine manner. Combined blocking of IL-6 receptor and inhibition of miR-21 significantly reversed CAF-mediated M-MDSC generation. Notably, the effects of CAFs on M-MDSC induction were abolished by inhibiting STAT3 signaling. Functionally, CAF-induced M-MDSCs promoted drug resistance of tumor cells upon cisplatin treatment. Clinically, ESCC patients with high infiltration of CAFs and CD11b+ myeloid cells had unfavorable predicted overall survival both in our cohort and in TCGA data. Taken together, our study reveals a paracrine and autocrine of IL-6 caused by CAFs co-activate STAT3 signaling, promoting the generation of M-MDSCs, and highlights the important role of CAFs in cooperation with M-MDSCs in promoting drug resistance, thus providing potential opportunities for reversing drug resistance through inhibition of STAT3 signaling.

Glioma stem cells (GSCs) contribute to the malignant growth of glioma, but little is known about the interaction between GSCs and tumor microenvironment. Here, we found that intense infiltration of regulatory T cells (Tregs) facilitated the qualities of GSCs through TGF-β secretion that helped coordinately tumor growth. Mechanistic investigations indicated that TGF-β acted on cancer cells to induce the core cancer stem cell-related genes CD133, SOX2, NESTIN, MUSASHI1 and ALDH1A expression and spheres formation via NF-κB–IL6–STAT3 signaling pathway, resulting in the increased cancer stemness and tumorigenic potential. Furthermore, Tregs promoted glioma tumor growth, and this effect could be abrogated with blockade of IL6 receptor by tocilizumab which also demonstrated certain level of therapeutic efficacy in xenograft model. Additionally, expression levels of CD133, IL6 and TGF-β were found to serve as prognosis markers of glioma patients. Collectively, our findings reveal a new immune-associated mechanism underlying Tregs-induced GSCs. Moreover, efforts to target this network may be an effective strategy for treating glioma. Supplementary Information The online version of this article (10.1007/s00262-021-02872-0) contains supplementary material, which is available to authorized users.

Objective: L1 cell adhesion molecule (L1CAM) exhibits oncogenic activity in tumors. However, the link between L1CAM and the tumor microenvironment remains poorly understood in patients with esophageal squamous cell carcinoma (ESCC). In this study, we investigated how L1CAM expression in ESCC affects the oncogenic characteristics of tumor cells and the tumor microenvironment. Methods: Human ESCC samples were collected, and the mRNA and protein levels of L1CAM were examined by real-time PCR and immunohistochemistry. Overexpression and knockdown gene expression assays were used for mechanistic studies. The cell proliferation and cell cycle were measured with CCK-8 assays and flow cytometry. Cell migration and invasion ability were measured with Transwell assays. Multiplex bead-based assays were performed to identity the factors downstream of L1CAM. Xenograft studies were performed in nude mice to evaluate the effects of L1CAM on tumor growth and regulatory T cell (Treg) recruitment. Results: L1CAM expression was significantly elevated in ESCC tissues (P < 0.001) and correlated with poorer prognosis (P < 0.05). Ablation of L1CAM in ESCC cells inhibited tumor growth and migration, and increased tumor cell apoptosis (P < 0.05). In the tumor microenvironment, L1CAM expression correlated with Treg infiltration in ESCC by affecting CCL22 secretion. Mechanistically, L1CAM facilitated CCL22 expression by activating the PI3K/Akt/NF-κB signaling pathway. Furthermore, CCL22 promoted Treg recruitment to the tumor site; the Tregs then secreted TGF-β, which in turn promoted L1CAM expression via Smad2/3 in a positive feedback loop. Conclusions: Our findings provide new insight into the mechanism of immune evasion mediated by L1CAM, suggesting that targeting L1CAM-CCL22-TGF-β crosstalk between tumor cells and Tregs may offer a unique means to improve treatment of patients with ESCC.

Natural killer (NK) cells, a predominant innate lymphocyte subset, mediates eradicating malignant cells. Purinergic signaling by ectonucleotidase CD39 can suppress T-cell response in caner. However, the role of CD39 in NK cells has not been fully elucidated. Here, we characterized CD39 expression on NK cells and its clinical relevance in esophageal squamous cell carcinoma (ESCC). Peripheral blood and tissue samples were collected from 36 ESCC patients. We observed that the proportion of NK cells significantly decreased but CD39 was obviously up-regulated on NK cells from cancerous tissues compared to paired peripheral blood in ESCC patients. Furthermore, tumor-infiltrating NK cells with high CD39 expression exhibited a phenotype of functional impairment. In vitro, conditioned media of ESCC cell lines could induce CD39 expression on peripheral NK cells from healthy donors. IL-6 was identified as the major cytokine produced by ESCC cell lines and also elevated in both tumor tissues and blood serum from ESCC patients. Recombinant IL-6 significantly induced surface CD39 expression in human NK cells, while IL-6-receptor antagonist tocilizumab prevented this effect. Finally, tumor-infiltrating CD39+ NK cells were correlated with poor prognosis in ESCC patients. Thus, tumor-derived IL-6 might impair NK cell functions through induction of CD39 expression. CD39+ NK cells may serve as a potential prognostic biomarker for ESCC patients.

Studies have shown that patients with lung adenocarcinoma exhibit a poor prognosis, and the overall effective rate of immunotherapy is relatively low. Previous studies reported on the BPIFB2 gene have shown that it participates in immune regulation in gastric cancer; however, the role and mechanisms of BPIFB2 in lung cancer remain unclear. The present study evaluated the mechanism of BPIFB2 in lung adenocarcinoma.First, the immune infiltration status of lung adenocarcinoma was analyzed by performing bioinformatics analysis and the BPIFB2 gene was screened. Expression of BPIFB2 in lung adenocarcinoma was studied in vitro, and it was confirmed that BPIFB2 exerted effects on the chemotaxis of tumor cells to T cells. The mechanism was further analyzed and verified via in vivo experiments. Finally, the molecular mechanism of the effect of BPIFB2 on tumor cell chemotaxis T cells was confirmed in clinical specimens.Patients with lung adenocarcinoma presented with different degrees of immune cell infiltration, wherein the tumor tissue exhibiting a low infiltration of CD8+T cells was defined as a cold tumor, demonstrating a high expression of BPIFB2. In vitro experiments revealed that although the knockdown of BPIFB2 exerted no significant effect on the proliferation and apoptosis of tumor cells, it could significantly increase the number of T cells presenting with chemotaxis in lung adenocarcinoma cells, and this might be attributable to a decrease in STAT3 activation and an increase in CCL5 expression after BPIFB2 knockdown. In vivo experiments showed that after BPIFB2 knockdown, the expression of CCL5 increased in tumor cells and the recruitment of T cells increased by tumor cells. It was also confirmed that the expression of BPIFB2 was negatively correlated with CCL5 expression in clinical specimens.Our study indicated that BPIFB2 was highly expressed in patients presenting with a cold tumor of lung adenocarcinoma. BPIFB2 knockdown increased the expression of CCL5 and the number of chemotactic CD8+T cells in lung adenocarcinoma. BPIFB2 may thus be considered an important target for immunotherapy.

Melanoma-associated Ag (MAGE)-C2, an immunogenic cancer germline (testis) Ag, is highly expressed by various tumor cells, thymic medullary epithelial cells, and germ cells. In this study, we aimed to explore the immunologic properties of MAGE-C2-specific CD8

Chimeric antigen receptor (CAR) T cells remain unsatisfactory in treating solid tumors. The frequency of tumor-infiltrating T cells is closely related to the good prognosis of patients. Augmenting T cell accumulation in the tumor microenvironment is essential for tumor clearance. To overcome insufficient immune cell infiltration, innovative CAR designs need to be developed immediately. CXCL9 plays a pivotal role in regulating T cell migration and inhibiting tumor angiogenesis. Therefore, we engineered CAR T cells expressing CXCL9 (CART-CXCL9). The addition of CXCL9 enhanced cytokine secretion and cytotoxicity of CAR T cells and endowed CAR T cells with the ability to recruit activated T cells and antiangiogenic effect. In tumor-bearing mice, CART-CXCL9 cells attracted more T cell trafficking to the tumor site and inhibited angiogenesis than conventional CAR T cells. Additionally, CART-CXCL9 cell therapy slowed tumor growth and prolonged mouse survival, displaying superior antitumor activity. Briefly, modifying CAR T cells to express CXCL9 could effectively improve CAR T cell efficacy against solid tumors.

The abundance and type of immune cells in the tumor microenvironment (TME) significantly influence immunotherapy and tumor progression. However, the role of immune cells in the TME of gastric cancer (GC) is poorly understood. We studied the correlations, proportion, and infiltration of immune and stromal cells in GC tumors. Data analyses showed a significant association of infiltration levels of specific immune cells with the pathological characteristics and clinical outcomes of GC. Furthermore, based on the difference in infiltration levels of immune and stromal cells, GC patients were divided into two categories, those with “immunologically hot” (hot) tumors and those with “immunologically cold” (cold) tumors. The assay for transposase‐accessible chromatin using sequencing and RNA sequencing analyses revealed that the hot and cold tumors had altered epigenomic and transcriptional profiles. Claudin‐3 (CLDN3) was found to have high expression in the cold tumors and negatively correlated with CD8+ T cells in GC. Overexpression of CLDN3 in GC cells inhibited the expression of MHC‐I and CXCL9. Finally, the differentially expressed genes between hot and cold tumors were utilized to generate a prognostic model, which predicted the overall survival of GC as well as patients with immunotherapy. Overall, we undertook a comprehensive analysis of the immune cell infiltration pattern in GC and provided an accurate model for predicting the prognosis of GC patients., Immune hot and cold tumors showed the difference in epigenetic and transcriptomic alterations. Claudin 3 (CLDN3) was negatively correlated with the infiltration of CD8+ T cells. Overexpression of CLDN3 in gastric cancer (GC) cells inhibited the expression of MHC‐I and CXCL9. The prediction model performed well in predicting overall survival of patients with GC and patients with immunotherapy treatment.

Gastric cancer has the fifth highest incidence of disease and is the third leading cause of cancer-associated mortality in the world. The etiology of gastric cancer is complex and needs to be fully elucidated. Thus, it is necessary to explore potential pathogenic genes and pathways that contribute to gastric cancer. Gene expression profiles of the GSE33335 and GSE54129 datasets were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were compared and identified using R software. The DEGs were then subjected to gene set enrichment analysis and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Survival analyses based on The Cancer Genome Atlas database were used to further screen the essential DEGs. A knockdown assay was performed to determine the function of the candidate gene in gastric cancer. Finally, the association between the candidate gene and immune-related genes was investigated. We found that GPNMB serves as an essential gene, with a high expression level, and predicts a worse outcome of gastric cancer. Knockdown of GPNMB inhibited gastric cancer cell proliferation and migration. In addition, GPNMB may augment the immunosuppressive ability of gastric cancer by recruiting immunosuppressive cells and promoting immune cell exhaustion through PI3K/AKT/CCL4 signaling axis. Collectively, these data suggest that GPNMB acts as an important positive mediator of tumor progression in gastric cancer, and GPNMB could exert multimodality modulation of gastric cancer-mediated immune suppression.

Lung cancer is the leading cause of cancer‐related deaths worldwide. Although several therapeutic strategies have been employed to curb lung cancer, the survival rate is still poor owing to the development of drug resistance. The mechanisms underlying drug resistance development are incompletely understood. Here, we aimed to identify the common signaling pathways involved in drug resistance in non‐small cell lung cancer (NSCLC). Three published transcriptome microarray data were downloaded from the Gene Expression Omnibus (GEO) database comprising different drug‐resistant cell lines and their parental cell lines. Differentially expressed genes (DEGs) were identified and used to perform Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. An overlapping analysis was performed for KEGG pathways enriched from all the three datasets to identify the common signaling pathways. As a result, we found that metabolic pathways, ubiquitin‐mediated proteolysis, and mitogen‐activated protein kinase (MAPK) signaling were the most aberrantly expressed signaling pathways. The knockdown of nicotinamide phosphoribosyltransferase (NAMPT), the gene involved in metabolic pathways and known to be upregulated in drug‐resistant tumor cells, was shown to increase the apoptosis of cisplatin‐resistant A549 cells following cisplatin treatment. Thus, our results provide an in‐depth analysis of the signaling pathways that are commonly altered in drug‐resistant NSCLC cell lines and highlight the potential strategy that facilitates the development of interventions to interfere with upregulated signaling pathways as well as to boost downregulated signaling pathways in drug‐resistant tumors for the elimination of multiple resistance of NSCLC.

CD204 is a specific marker of tumor‐associated macrophages (TAMs) in glioma. However, the expression levels of CD204 and its involvement in glioma are not fully understood. In this large‐scale study, we assessed the expression and function of CD204 in whole‐grade glioma molecularly and clinically. In total, 1323 glioma samples, including 301 microarray data and 325 RNA‐seq data from the Chinese Glioma Genome Atlas (CGGA) dataset and 697 RNA‐seq data from The Cancer Genome Atlas (TCGA) dataset, were utilized. The statistical analysis and graphical work were mainly performed using the R software. Univariate and multivariate Cox analysis demonstrated that CD204 was an independent prognosticator in glioma patients. CD204 expression was positively correlated with the grade of malignancy. CD204 was consistently upregulated in wild‐type isocitrate dehydrogenase glioma and highly expressed in mesenchymal glioblastoma. Gene ontology of CD204‐related genes showed that CD204 was most enriched in inflammatory response and immune response. It was associated with the stromal and immune populations, especially the monocytic lineage, fibroblasts, and T cells. Circos plots revealed that CD204 was closely associated with many immune checkpoint regulators, especially TIM‐3. CD204 expression is consistent with the malignant phenotype of glioma and independently predicts poor outcomes in glioma patients. Additionally, CD204+ TAMs, collaborating with other checkpoint members, may contribute to the dysfunction of T cells. These findings suggest that CD204 may be a promising target for glioma immunotherapy.

Mutations in the isocitrate dehydrogenase (IDH) 1 gene, especially the R132H mutation, have been reported to be associated with a better prognosis in glioma patients. However, the underlying molecular mechanisms are not yet well understood. Many factors may contribute to differences in the survival of IDH1 wild-type and IDH1 mutant glioma patients, in which immune components play a potentially important role. In this study, we analyzed The Cancer Genome Atlas (TCGA), and the Chinese Glioma Genome Atlas (CGGA) databases, as well as glioma patient-derived tumor samples. We found that there was a higher infiltration of natural killer (NK) cells in IDH1 mutant glioma patients, and this was correlated with a better prognosis. We also showed that IDH1-R132 tumor cells had higher expression levels of the chemokine CX3CL1. This arises as a result of the conversion of α-ketoglutarate to R(-)-2-hydroxyglutarate by the IDH1 mutant and the resultant phosphorylation of nuclear factor kappa B. Knockdown of CX3CL1 decreased the migration of NK cells. In addition, the high levels of expression of CX3CL1 were positively correlated with glioma patient survival in the TCGA and CGGA databases, and in the clinical samples. Overall, our data have identified a novel mechanism in which R132H mutation of the IDH1 gene serves as a tumor suppressor by promoting the recruitment of NK cells through CX3CL1/CX3CR1 chemotaxis.

Urothelial bladder cancer (UBC) is the most common malignant tumor of the urinary system. Most patients do not benefit from treatment with immune checkpoint inhibitors, which are closely associated with immune profiling in the context of UBC. Therefore, we aimed to characterize the immune profile of UBC to identify different immune subtypes that may influence therapy choice. We identified four subtypes of UBC based on immune profiling including immune ignorant, cold tumor, immune inactive, and hot tumor. After excluding the cold tumor subtype because of its unique pathology distinct from the other types, a high correlation between patient survival and immune characteristics was observed. Most immune cell types had highly infiltrated the hot tumor subtype compared to other subtypes. Interestingly, although immune cells infiltrated the tumor microenvironment, they exhibited an exhaustion phenotype. CCL4 may be the key molecule functioning in immune cell infiltration in the hot tumor subtype. Moreover, neutrophils may function as an important suppressor in the tumor microenvironment of the immune ignorant and immune inactive subtypes. Furthermore, different tumor-intrinsic signaling pathways were involved in immune cell infiltration and exclusion in these four different subtypes. Immune profiling could serve as a prognostic biomarker for UBC, and has potential to guide treatment decisions in UBC. Targeting tumor-intrinsic signaling pathways may be a promising strategy to treat UBC.

Background Esophageal squamous cell carcinoma (ESCC) is the main pathological subtype of esophageal cancer with high incidence and mortality. Immune and stromal cells in the tumor microenvironment (TME) profoundly affect the development of ESCC. Methods In this study, we used the ESTIMATE algorithm to calculate the immune and stromal scores of ESCC samples in The Cancer Genome Atlas (TCGA) database. Next, we used the R package limma to identify differentially expressed genes (DEGs) from high- versus low-immune/stromal score groups and these DEGs were further utilized to analyze the functional annotations, protein-protein interaction (PPI) networks and overall survival of patients with ESCC. Finally, we identified the biological roles of core gene C3AR1 in the TME of ESCC using the TCGA database and in vitro experiments. Results We obtained the immune and stromal scores of ESCC samples and further evaluated the impact of these scores on the prognosis and clinical parameters of patients with ESCC. Next, we identified 410 DEGs from high- versus low-immune/stromal score groups and to gain better understanding of the biological functions and characteristics of DEGs. Among these DEGs, 69 were correlated with the overall survival of patients with ESCC and C3AR1 was identified as a core gene for the regulation of most genes in the network. We found that C3AR1 was positively correlated with M2 macrophages and immune inhibitory molecules (T-cell immunoglobulin and mucin domain 3 (TIM-3), programmed cell death-1 (PD-1)), but not with M1 macrophages. We also observed a higher expression of CD163 and CD206, which were the markers for M2 macrophages in the TLQP-21 TFA (the agonist of C3AR1)groups than in the control groups. Conclusion Based on the ESTIMATE algorithm, we obtained and characterized prognosis-related genes in the TME of ESCC samples from the TCGA database. We have further revealed that C3AR1 may cause an immunosuppressive microenvironment by affecting the polarization of macrophages to M2 phenotype and lead to the progression of ESCC, which indicates that C3AR1 may be a potential target for immunotherapy.

Background: Glioma stem cells (GSCs) contribute to the malignant growth of glioma, but little is known about the interaction between GSCs and the tumor microenvironment (TME). The aim of this study was to examine how regulatory T cells (Tregs) increase the stemness and tumorigenic potential of glioma cells.Methods: Tumor and peripheral blood samples were collected during surgery from 86 patients with glioma, and 75 samples of adjacent noncancerous tissue were collected, and Regulatory T cells (Tregs) were extracted from blood. Cytological and histochemical analyses were conducted to examine the mechanisms of Treg action on cancer cells. A mouse glioma model was used.Results: Intense infiltration by Tregs facilitated the qualities of GSCs through TGF-β secretion, which helped to coordinate tumor growth. Mechanistic investigations indicated that TGF-b acted on cancer cells to induce expression of the core cancer stem cell-related genes ( CD133, SOX2, NESTIN, MUSASHI1, and ALDH1A ) and to induce sphere formation via the NF-κB–IL6–STAT3 signaling pathway, resulting in increased cancer stemness and tumorigenic potential. Tregs promoted glioma tumor growth, and this effect was abrogated by blockade of the IL6 receptor by tocilizumab, which also demonstrated some therapeutic efficacy in a xenograft model. Expression levels of CD133, IL6 and TGF-β were found to serve as prognostic markers for glioma.Conclusions: Our findings reveal a new immune-associated mechanism underlying Treg-induced GSCs. Efforts to target this network may provide an effective strategy for treating glioma.

Maelstrom (MAEL) is a novel cancer/testis-associated gene, which is not only expressed in the male testicular germ cells among human normal tissues, but is also aberrantly expressed in various cancer tissues. In our study, MAEL was characterized as a tumor-promoting gene and was significantly associated with esophageal squamous cell carcinoma (ESCC) recurrence and unfavorable prognosis. Kaplan–Meier analysis showed that patients with high MAEL expression had a shorter survival time. Functional experiments showed that MAEL promoted tumor cell growth and inhibited cell apoptosis. These results prompted us to investigate the factors affecting the tumorigenicity of MAEL. Further experimentation demonstrated that MAEL enhanced the expression of phosphorylated Akt1, with subsequent phosphorylation of nuclear factor kappa B (NF-κB) subunit RelA in tumor cells, and chemoattracted myeloid-derived suppressor cells (MDSCs) by upregulating interleukin-8 (IL8) to accelerate tumor progression in the tumor microenvironment. We also found that TGFβ secreted by MDSCs could upregulate MAEL by inducing Smad2/Smad3 phosphorylation. In summary, this study revealed a mechanism by which MAEL could upregulate IL8 through Akt1/RelA to direct MDSCs homing into the tumor, suggesting that MAEL could be an attractive therapeutic target and a prognostic marker against ESCC. Cancer Immunol Res; 6(10); 1246–59. ©2018 AACR.

Background: Accumulating evidence indicated that the CXC chemokine receptor (CXCR) 7 (CXCR7) was overexpressed in a variety of tumors. However, the value of the CXCR7 expression in predicting prognosis in solid tumors remains controversial. Therefore, we performed this meta-analysis to evaluate the correlation between CXCR7 expression and lymph node metastasis (LNM), tumor pathological grade and survival, including overall survival (OS), disease-free survival (DFS) and recurrence-free survival (RFS). Methods: Eligible studies were searched in PubMed, Web of Science, and PMC up to April 2018. A total of 27 studies were included in this meta-analysis. Odds ratio (OR), hazard ratio (HR) and 95 % confidence intervals (CI) were used as effect measures. Results: The meta-analysis showed that high expression of CXCR7 predicted a high risk of LNM (pooled OR = 2.22, 95%CI: 1.41-3.50), high tumor grade (pooled OR = 1.94, 95%CI: 1.20-3.13), poor OS (pooled HR = 1.66, 95%CI: 1.30-2.03), and poor DFS/RFS (pooled HR = 1.82, 95%CI: 1.21-2.43). Subgroup analysis showed that CXCR7 expression had a positive correlation with LNM in pan-adenocarcinoma subgroup (pooled OR = 3.73, 95%CI: 2.21-6.30), while no correlation was found in pan-squamous cancer subgroup (pooled OR = 1.29, 95%CI: 0.56-2.96). Subgroup analysis of tumor grade revealed that high expression of CXCR7 predicted high tumor grade both in pan-squamous cancer and pan-adenocarcinoma (pooled OR = 3.58, 95%CI: 1.39-9.22, pooled OR = 2.25, 95%CI: 1.20-4.20). As in OS group, we divided the data based on analysis method and it turned out that overexpressed CXCR7 predicted worse OS both in multivariate analysis (pooled HR =1.57, 95%CI: 1.12-2.01) and univariate analysis subgroup (pooled HR =1.86, 95%CI: 1.23-2.49). Conclusions: Our meta-analysis revealed that high expression of CXCR7 predicted unfavorable prognosis and may serve as potential targets of cancer therapy.

Mutations in the isocitrate dehydrogenase (IDH) 1 gene, especially the R132H mutation, have been reported to be associated with a better prognosis in glioma patients. However, the underlying molecular mechanisms are not yet well understood. Many factors may contribute to differences in the survival of IDH1 wild-type and IDH1 mutant glioma patients, in which immune components play a potentially important role. In this study, we analyzed The Cancer Genome Atlas (TCGA), and the Chinese Glioma Genome Atlas (CGGA) databases, as well as glioma patient-derived tumor samples. We found that there was a higher infiltration of natural killer (NK) cells in IDH1 mutant glioma patients, and this was correlated with a better prognosis. We also showed that IDH1-R132 tumor cells had higher expression levels of the chemokine CX3CL1. This arises as a result of the conversion of α-ketoglutarate to R(-)-2-hydroxyglutarate by the IDH1 mutant and the resultant phosphorylation of nuclear factor kappa B. Knockdown of CX3CL1 decreased the migration of NK cells. In addition, the high levels of expression of CX3CL1 were positively correlated with glioma patient survival in the TCGA and CGGA databases, and in the clinical samples. Overall, our data have identified a novel mechanism in which R132H mutation of the IDH1 gene serves as a tumor suppressor by promoting the recruitment of NK cells through CX3CL1/CX3CR1 chemotaxis.

Purpose: Tumor development has been closely linked to tumor microenvironment, particularly in terms of myeloid-derived suppressive cells (MDSCs), a heterogeneous population of immature myeloid cells that protect tumors from elimination by immune cells. Approaches aimed at blocking MDSC accumulation could improve cancer clinical outcome. Experimental Design: We investigated that metformin suppressed MDSC migration to inhibit cancer progression. Primary tumor tissues were incubated with metformin, and proinflammatory chemokine production was measured. To study MDSC chemotaxis in vivo, BALB/C nude mice were injected subcutaneously with TE7 cells and treated with metformin. Migration of adoptively transferred MDSCs was analyzed using flow cytometry and immunohistochemistry. Results: The frequency of tumor-infiltrated polymorphonuclear (PMN)-MDSCs was increased compared to their circulating counterparts. There was a significant correlation between PMN-MDSCs accumulation in tumors and ESCC prognosis. Moreover, PMN-MDSCs displayed immunosuppressive activity in vitro. Treatment with metformin reduced MDSC migration in patients. Metformin inhibited CXCL1 secretion in ESCC cells and tumor xenografts by enhancing AMPK phosphorylation and inducing DACH1 expression, leading to NF-κB inhibition and reducing MDSC migration. Knockdown of AMPK and DACH1 expression blocked the effect of metformin on MDSC chemotaxis. Conclusions: A novel anti-tumor effect of metformin, which is mediated by reducing PMN-MDSC accumulation in the tumor microenvironment via AMPK/DACH1/CXCL1 axis.