Guohui Qin

Inhibition of SALL4 reduces tumorigenicity involving epithelial-mesenchymal transition via Wnt/β-catenin pathway in esophageal squamous cell carcinoma

BackgroundGrowing evidence suggests that SALL4 plays a vital role in tumor progression and metastasis. However, the molecular mechanism of SALL4 promoting esophageal squamous cell carcinoma (ESCC) remains to be elucidated.MethodsThe gene and protein expression profiles- were examined by using quantitative real-time PCR, immunohistochemistry and western blotting. Small hairpin RNA was used to evaluate the role of SALL4 both in cell lines and in animal models. Cell proliferation, apoptosis and invasion were assessed by CCK8, flow cytometry and transwell-matrigel assays. Sphere formation assay was used for cancer stem cell derivation and characterization.ResultsOur study showed that the transcription factor SALL4 was overexpressed in a majority of human ESCC tissues and closely correlated with a poor outcome. We established the lentiviral system using short hairpin RNA to knockdown SALL4 in TE7 and EC109 cells. Silencing of SALL4 inhibited the cell proliferation, induced apoptosis and the G1 phase arrest in cell cycle, decreased the ability of migration/invasion, clonogenicity and stemness in vitro. Besides, down-regulation of SALL4 enhanced the ESCC cells’ sensitivity to cisplatin. Xenograft tumor models showed that silencing of SALL4 decreased the ability to form tumors in vivo. Furthermore, our study demonstrated that SALL4 played a vital role in modulating the stemness of ESCC cells via Wnt/β-catenin signaling pathway and in epithelial-mesenchymal transition.ConclusionsOur results revealed that SALL4 might serve as a functional marker for ESCC cancer stem cell, a crucial marker for prognosis and an attractive candidate for target therapy of ESCC.

Correlation between the high expression levels of cancer-germline genes with clinical characteristics in esophageal squamous cell carcinoma.

Antigens encoded by cancer-germline genes are attractive targets for cancer immunotherapy. In this study, we aimed to evaluate the mRNA expression of cancer-germline genes, expression of the encoded proteins in patients with esophageal squamous cell carcinoma (ESCC) and their correlations with clinical characteristics. In addition, the effects of downregulation cancer-germline genes on ESCC cells were assessed in vitro. Our results showed that cancer-germline genes were frequently expressed in ESCC samples. The positive rates of in ESCC samples were: 87% of MAGE-A3, 60% of MAGE-A4, 65% of MAGE-C2, and 20% of NY-ESO-1 at mRNA level. MAGE-A3 expression was associated with age, lymph node metastasis and tumor stage (all P<0.05), while MAGE-C2 expression was only associated with tumor stage (P<0.05). Furthermore, the MAGE-A3 expressing patients had a poorer overall survival (P<0.05). Multivariate analysis identified MAGE-A3 as an independent poor prognostic marker in ESCC. In vitro assay, ESCC cell lines treated with specific siRNAs to down-regulate MAGE-A3 and MAGE-C2 resulted in decreased colony-formation and migration ability (P<0.05). Epithelial marker E-cadherin was up-regulated in siRNA-MAGE-A3/C2 cells compared to controls, whereas mesenchymal markers Vimentin, N-cadherin and Slug were downregulated (all P<0.05), suggesting a role for MAGE-A3/C2 in ESCC metastasis through inducing epithelial-mesenchymal transition. The present study revealed that cancer-germline genes and their encoded proteins were frequently expressed in ESCC tumor samples and were related to poor prognosis. Thus, cancer-germline genes may serve as useful biomarkers and potential targets for ESCC patients.

Metformin-Induced Reduction of CD39 and CD73 Blocks Myeloid-Derived Suppressor Cell Activity in Patients with Ovarian Cancer

Metformin is a broadly prescribed drug for type 2 diabetes that exerts antitumor activity, yet the mechanisms underlying this activity remain unclear. We show here that metformin treatment blocks the suppressive function of myeloid-derived suppressor cells (MDSC) in patients with ovarian cancer by downregulating the expression and ectoenzymatic activity of CD39 and CD73 on monocytic and polymononuclear MDSC subsets. Metformin triggered activation of AMP-activated protein kinase α and subsequently suppressed hypoxia-inducible factor α, which was critical for induction of CD39/CD73 expression in MDSC. Furthermore, metformin treatment correlated with longer overall survival in diabetic patients with ovarian cancer, which was accompanied by a metformin-induced reduction in the frequency of circulating CD39+CD73+ MDSC and a concomitant increase in the antitumor activities of circulating CD8+ T cells. Our results highlight a direct effect of metformin on MDSC and suggest that metformin may yield clinical benefit through improvement of antitumor T-cell immunity by dampening CD39/CD73-dependent MDSC immunosuppression in ovarian cancer patients.Significance: The antitumor activity of an antidiabetes drug is attributable to reduced immunosuppressive activity of myeloid-derived tumor suppressor cells. Cancer Res; 78(7); 1779-91. ©2018 AACR.

Metformin blocks myeloid-derived suppressor cell accumulation through AMPK-DACH1-CXCL1 axis

ABSTRACT 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.

WASH overexpression enhances cancer stem cell properties and correlates with poor prognosis of esophageal carcinoma.

There is increasing evidence that cytoskeleton remodeling is involved in cancer progression. Wiskott‐Aldrich syndrome protein (WASP) family represents a key regulator of actin cytoskeleton remodeling. However, the underlying mechanism of the WASP family in cancer progression remains elusive. Here, we studied the role of WASP and SCAR Homolog (WASH), a recently identified WASP family member, in human esophageal squamous cell carcinoma (ESCC). Using three human ESCC cell lines, we found that WASH expression was significantly elevated in cancer stem‐like cells enriched by sphere formation assay. WASH knockdown decreased the sphere‐forming capacity of esophageal cancer cells whereas WASH over‐expression exhibited the opposite effect. Mechanistically, we identified interleukin‐8 (IL‐8) as a key downstream target of WASH. IL‐8 knockdown completely attenuated tumor sphere formation induced by WASH overexpression. WASH knockdown also delayed the growth of human ESCC xenografts in BALB/c nude mice. Importantly, high WASH levels were associated with poor clinical prognosis in a total of 145 human ESCC tissues. Collectively, our results suggest an essential role of the WASH/IL‐8 pathway in human ESCC by maintaining the stemness of cancer cells. Hence, targeting this pathway might represent a promising strategy to control human esophageal carcinoma.

miR-143 Regulates Memory T Cell Differentiation by Reprogramming T Cell Metabolism

MicroRNAs are an important regulator for T cell immune response. In this study, we aimed to identify microRNAs with the potential to regulate T cell differentiation. The influence of miR-143 on differentiation and function of CD8+ T cells from healthy donors were detected, and it was found that miR-143 overexpression could significantly increase the differentiation of central memory T (Tcm) CD8+ cells, decrease cell apoptosis, and increase proinflammatory cytokine secretion. Furthermore, the specific killing of HER2-CAR T cells against esophageal cancer cell line TE-7 was enhanced by miR-143 overexpression. Glucose transporter 1 (Glut-1) was identified as the critical target gene of miR-143 in the role of T cell regulation. By inhibition Glut-1, miR-143 inhibited glucose uptake and glycolysis in T cell to regulated T cell differentiation. Tcm cell populations were also suppressed in parallel with the downregulation of miR-143 in tumor tissues from 13 patients with esophagus cancer. IDO and its metabolite kynurenine in the tumor microenvironment were screened as an upstream regulator of miR-143. IDO small interfering RNA significantly increased the expression of miR-143 and Tcm cell population. In conclusion, our results show that miR-143 enhanced antitumor effects of T cell by promoting memory T cell differentiation and metabolism reprogramming through Glut-1. Our findings will encourage the development of new strategies targeting miR-143 in both cancer cells and T cells.

Role of CXCR7 as a Common Predictor for Prognosis in Solid Tumors: a Meta-Analysis

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.

Dual TGF-β and PD-1 blockade synergistically enhances MAGE-A3-specific CD8+ T cell response in esophageal squamous cell carcinoma: T cell response in esophageal squamous cell carcinoma

PD‐1 is highly expressed on tumor‐infiltrated antigen‐specific T cells and limit the antitumor function. Blocking of PD‐1/PD‐L1 signaling has shown unprecedented curative efficacies in patients with advanced cancer. However, only a limited population of patients benefited from such therapies. Our study aimed to explore biological properties, functional regulation and reversal of MAGE‐A3‐specific CD8+ T cells in patients with esophageal squamous cell carcinoma (ESCC). The underlying principle of deficiency and restoring MAGE‐A3‐specific CD8+ T cells function in tumor microenvironment (TME) was evaluated. MAGE‐A3‐specific CD8+ T cells could lyse HLA‐A2+/MAGE‐A3+ tumor cells. Tetramer+ T cell frequency was higher in elder patients, but lower in patients with lymph node metastasis and late tumor stage (p < 0.05). CD107ahigh expression on functional T cells was an independent prognostic factor in Cox regression analysis. PD‐1 was highly expressed on dysfunctional antigen‐specific CD8+ T cells and tumor infiltrating T lymphocytes (p < 0.05). Myeloid‐derived suppressor cells (MDSCs) derived‐TGF‐β mediated PD‐1high expression on CD8+ T cells, which led to be resistance to PD‐1/PD‐L1 blockade in TME. Dual PD‐1/PD‐L1 and TGF‐β signaling pathway blockades synergistically restored the function and antitumor ability of antigen‐specific CD8+ T cells in vitro/vivo assay. The presence of functional MAGE‐A3‐specific CD8+ T cells had an independent prognostic impact on survival of patients with ESCC. Furthermore, MDSCs‐derived TGF‐β increased PD‐1 expression on T cells and decreased the sensitivity to PD‐1/PD‐L1 blockade. Combining T cell‐based therapy with dual PD‐1/PD‐L1 and TGF‐β signaling pathway blockade could be considered a promising strategy for cancer treatment.

A cycle involving HMGB1, IFN-γ and dendritic cells plays a putative role in anti-tumor immunity

An important subset in regulating antitumor immunity is the maturation and accumulation of intratumor dendritic cells (DCs), inducing potent T cell cytotoxicity. In this study, we explored how the soluble abundant high-mobility group box 1 protein (HMGB1) affected DC activation and retention within lung cancers, and in which way the resultant interferon-γ (IFN-γ) further enhanced DC maturation and accumulation. It was discovered that HMGB1 was correlated with DC markers HLA-DR and CD86 in lung cancers at both mRNA and protein level. Further analyses showed HMGB1 enhanced the maturation of DCs, indicated by upregulated IFN-γ in CD8+ T cells. Additionally, HMGB1 increased the accumulation of DCs by promoting CCR5 and CXCR3 production. Moreover, the resultant IFN-γ elevated the levels of HMGB1 and DC-associated chemokines, CCL5, CXCL10 and CXCL11 in tumor cells. Hence, the HMGB1-IFN-γ cycle may represent an important mechanism underlying DC-mediated anti-tumor immune response.

Maelstrom Directs Myeloid-Derived Suppressor Cells to Promote Esophageal Squamous Cell Carcinoma Progression via Activation of the Akt1/RelA/IL8 Signaling Pathway

Maelstrom directly and indirectly promotes growth of esophageal squamous cell carcinomas. MDSCs, recruited to the tumors microenvironment through IL8 signaling, produce TGFβ that then regulates maelstrom expression in the tumor cells by inducing Smad2/Smad3 phosphorylation. 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.