Jinpu Yu

Myeloid-Derived Suppressor Cells Suppress Antitumor Immune Responses through IDO Expression and Correlate with Lymph Node Metastasis in Patients with Breast Cancer

Myeloid-derived suppressor cells (MDSCs) represent heterogeneous immunosuppressive cells in multiple cancer types and display potent immunosuppressive activity on T cells. We have shown the increased expression of IDO in breast cancer. Because IDO plays a pivotal role in immune tolerance via suppressing T cell function, the aim of this study was to investigate the expression of IDO in MDSCs in breast cancer and its role in MDSC-mediated inhibition of immune surveillance. The proportion of MDSCs with the phenotype of CD45+CD13+CD33+CD14−CD15− significantly increased in primary cancer tissues and patients’ peripheral blood. IDO expression was significantly upregulated in MDSCs isolated from fresh breast cancer tissues (fresh MDSCs [fMDSCs]), which correlated with increased infiltration of Foxp3+ regulatory T cells in tumors and lymph node metastasis in patients. fMDSCs inhibited IL-2 and anti-CD3/CD28 mAb-induced T cell amplification and Th1 polarization but stimulated apoptosis in T cells in an IDO-dependent manner. CD33+ progenitors isolated from healthy donors’ umbilical cord blood were cocultured with breast cancer cell line MDA-MB-231 cells to induce MDSCs. IDO expression was upregulated in induced MDSCs, which required phosphorylation of STAT3, but not STAT1. IDO was required for induced MDSCs’ immunosuppressive activity on T cells, which was blocked by IDO inhibitor 1-methyl-L-tryptophan or STAT3 antagonist JSI-124. Consistently, increased STAT3 phosphorylation level was found in fMDSCs. Together, our findings suggest that STAT3-dependent IDO expression mediates immunosuppressive effects of MDSCs in breast cancer. Thus, inhibition of MDSC-induced T cell suppression by blocking IDO may represent a previously unrecognized mechanism underlying immunotherapy for breast cancer.

The role of miRNA-29 family in cancer

The miRNA-29 family of microRNAs (miRNAs), including miR-29a, miR-29b and miR-29c, was recently reported to be aberrantly expressed in multiple cancers. Increasing evidence shows that the abnormal expression of miR-29 family is associated with tumorigenesis and cancer progression, making miR-29s a well-analyzed group of miRNAs in cancer research. Here, in this review we aim to provide an overview of the role of miR-29 family in the pathophysiologic changes of cancer cells and the epigenetic and immune regulation through the biological function of miR-29s.

Randomized Study of Autologous Cytokine-Induced Killer Cell Immunotherapy in Metastatic Renal Carcinoma

Purpose: The therapeutic benefit of the cytokine-induced killer (CIK) cells was unknown in the renal cell carcinoma (RCC). This prospectively randomized study was conducted to evaluate the effects of autologous CIK cell immunotherapy in patients with metastatic clear cell RCCs. Experimental Design: From June 2005 to June 2008, 148 patients with metastatic clear cell RCC were randomized to autologous CIK cell immunotherapy (arm 1, n = 74), or interleukin-2 treatment combination with IFN-α-2a (arm 2, n = 74). The primary endpoint was overall survival (OS) and secondary endpoint was progression-free survival (PFS) evaluated by Kaplan–Meier analyses and treatment HRs with the Cox proportional hazards model. Results: The 3-year PFS and OS in arm 1 were 18% and 61%, as compared with 12% and 23% in arm 2 (P = 0.031 and <0.001, respectively). The median PFS and OS in arm 1 were significantly longer than those in arm 2 (PFS, 12 vs. 8 months, P = 0.024; OS, 46 vs. 19 months, P < 0.001). Multivariate analyses indicated that the cycle count of CIK cell immunotherapy as a continuous variable was significantly associated with prolonged PFS [HR = 0.88; 95% confidence interval (CI), 0.84-0.93; P < 0.001] and OS (HR = 0.58; 95% CI, 0.48–0.69; P < 0.001) in arm 1. Conclusion: The data suggested that CIK cell immunotherapy could improve the prognosis of metastatic clear cell RCC, and increased cycle count of CIK cell treatment could further enhance the beneficial effects. Clin Cancer Res; 18(6); 1751–9. ©2012 AACR.

Dendritic cell-activated cytokine-induced killer cells enhance the anti-tumor effect of chemotherapy on non-small cell lung cancer in patients after surgery

BACKGROUND AIMS Cytokine-induced killer (CIK) cells have shown cytolytic activity against several tumor cells in vitro and in animal tumor models. Furthermore, CIK cells activated by dendritic cell (DC) stimulation show increased anti-tumor activity. This study aimed to evaluate the clinical efficacy of DC-activated CIK cell treatment following regular chemotherapy and the effects of this therapy on immune responses in patients with non-small cell lung cancer (NSCLC) after surgery. METHODS A paired study, with 42 patients in each group with stage I-IIIa NSCLC after surgery, was performed. Patients received chemotherapy alone (CT) or chemotherapy and DC-activated CIK cell treatment (immuno-CT). Disease-free survival (DFS) and overall survival were evaluated. CIK cell cytotoxicity against tumor cells was detected using a lactate dehydrogenase-based method. Serum cytokine levels in the immuno-CT group were detected using cytokine antibody arrays. RESULTS The cytotoxicity of CIK cells was significantly enhanced by DC activation. The 2-year overall survival rate in the immuno-CT group was significantly improved compared with the CT group (94.7 +/- 3.6% versus 78.8 +/- 7.0%, P < 0.05). The 2-year DFS of these two groups showed no significant difference. DC-activated CIK cell treatment increased production of cytokines that have known anti-tumor effects, including IFN-gamma, MIG, TNF-alpha and TNF-beta, in patients who had no progression, but they were not found in patients who developed recurrence/metastasis. CONCLUSIONS This study suggests that the role of DC-activated CIK cells in improvement of chemotherapy for malignant tumor treatment is associated with up-regulation of the production of cytokines involved in the anti-tumor effect.

Diagnostic and prognostic value of circulating miR-21 for cancer: A systematic review and meta-analysis

BACKGROUND MicroRNAs (miRNAs) have been reported to be aberrantly expressed in patients with cancer. Many studies have shown that circulating miRNAs could play potential roles as diagnostic and prognostic biomarkers of cancers. The aim of this meta-analysis is to summarize the role of circulating miR-21 as a biomarker in patients with a variety of carcinomas. MATERIAL AND METHODS Eligible studies were identified and assessed for quality through multiple search strategies. For diagnostic meta-analysis, the sensitivity, specificity, and other measures of miR-21 in the diagnosis of cancer were pooled using bivariate random-effects approach models. For prognostic meta-analysis, pooled hazard ratios (HRs) of circulating miR-21 for survival were calculated. RESULTS A total of 36 studies dealing with various carcinomas were included for the systemic review. Among them, 23 studies were finally enrolled in the global meta-analysis (17 studies for diagnosis and 6 studies for prognosis). For diagnostic meta-analysis, the overall pooled results for sensitivity, specificity, positive likelihood ratio (LRP), negative likelihood ratios (LRN) and diagnostic odds ratio (DOR) were 75.7% (95% CI: 67.1%-82.6%), 79.3% (95% CI: 74.2%-83.5%), 3.65 (95% CI: 2.83-4.70), 0.31 (95% CI: 0.22-0.43), and 11.88 (95% CI: 6.99-20.19), respectively. For prognostic meta-analysis, the pooled HR of higher miR-21 expression in circulation was 2.37 (95% CI: 1.83-3.06, P<0.001), which could significantly predict poorer survival in general carcinomas. Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with worse overall survival (OS) significantly in carcinomas of digestion system (HR, 5.77 [95% CI: 2.65-12.52]). CONCLUSIONS Our findings suggest that circulating miR-21 may not suitable to be a diagnostic biomarker, but it has a prognostic value in patients with cancer.

Long non-coding RNA HOTAIR promotes tumor cell invasion and metastasis by recruiting EZH2 and repressing E-cadherin in oral squamous cell carcinoma

HOX transcript antisense RNA (HOTAIR), a long intergenic non-coding RNA (lncRNA), functions as a molecular scaffold to link and target the histone modification complexes PRC2 and LSD1, then reprograms chromatin states by coupling histone H3K27 methylation and H3K4 demethylation for epigenetic gene silencing to promote cancer metastasis. It is associated with poor survival in several solid cancers. In this study, we show that HOTAIR expression increased in oral squamous cell carcinoma (OSCC) compared with non-tumor tissue and is associated with metastasis, the stage and histological differentiation. In addition, overexpression of HOTAIR indicated poor overall survival (OS) and disease-free survival (DFS) in OSCC patients. Knockdown of HOTAIR by siRNA in OSCC cells decreased cell proliferation and colony formation, increased cell invasion and migration, and induced apoptosis in vitro. Furthermore, significant negative correlation between HOTAIR levels and E-cadherin levels was found in OSCC tissues and cell lines, and HOTAIR contributed to the regulation of E-cadherin through binding to EZH2 and H3K27me3 with the E-cadherin promoter. Our findings suggest that HOTAIR expression is associated with OSCC and may be one of critical targets in progression and metastasis, and an indicator of poor survival in OSCC.

Long noncoding RNA HOTAIR involvement in cancer

Evidences have been provided that long noncoding RNAs (lncRNAs) act as key molecules in epigenetic regulation and are involved in the development process of cancer in recent studies. HOX transcript antisense RNA (HOTAIR), a long intergenic noncoding RNA (lincRNA), functions as a molecular scaffold to link and target two histone modification complexes PRC2 and LSD1, then reprograms chromatin states by couples histone H3K27 methylation and H3K4 demethylation for epigenetic gene silencing to promote cancer metastasis. HOTAIR, regarded as an oncogene, is pervasively overexpressed in most solid cancers and correlated with tumor invasion, progression, metastasis, and poor prognosis, and HOTAIR has been proven to play a critical role in most biological process of cancer and would be a potential new target in cancer therapy.

Noncanonical NF-κB Activation Mediates STAT3-Stimulated IDO Upregulation in Myeloid-Derived Suppressor Cells in Breast Cancer

Immunotherapy for cancer treatment is achieved through the activation of competent immune effector cells and the inhibition of immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs). Although MDSCs have been shown to contribute to breast cancer development, the mechanism underlying MDSC-mediated immunosuppression is unclear. We have identified a poorly differentiated MDSC subset in breast cancer–suppressing T cell function through STAT3-dependent IDO upregulation. In this study we investigated the mechanisms underlying aberrant expression of IDO in MDSCs. MDSCs were induced by coculturing human CD33+ myeloid progenitors with MDA-MB-231 breast cancer cells. Increased STAT3 activation in MDSCs was correlated with activation of the noncanonical NF-κB pathway, including increased NF-κB–inducing kinase (NIK) protein level, phosphorylation of cytoplasmic inhibitor of NF-κB kinase α and p100, and RelB-p52 nuclear translocation. Blocking STAT3 activation with the small molecule inhibitor JSI-124 significantly inhibited the accumulation of NIK and IDO expression in MDSCs. Knockdown of NIK in MDSCs suppressed IDO expression but not STAT3 activation. RelB-p52 dimers were found to directly bind to the IDO promoter, leading to IDO expression in MDSCs. IL-6 was found to stimulate STAT3-dependent, NF-κB–mediated IDO upregulation in MDSCs. Furthermore, significant positive correlation between the numbers of pSTAT3+ MDSCs, IDO+ MDSCs, and NIK+ MDSCs was observed in human breast cancers. These results demonstrate a STAT3/NF-κB/IDO pathway in breast cancer–derived MDSCs, which provides insight into understanding immunosuppressive mechanisms of MDSCs in breast cancer.

Fibroblast activation protein: A potential therapeutic target in cancer

The concept of targeting antigens selectively expressed on the surface of tumor capillary endothelial cells or in tumor stroma has emerged as a promising strategy for cancer therapeutics. Identification of stromal targets for anticancer therapy and development of selective inhibitors of these targets are of great clinical interest. Fibroblast activation protein (FAP), a member of the serine protease family, selectively expressed in the stromal fibroblasts associated with epithelial cancers, whereas with low or undetectable expression in the resting fibroblasts of normal adult tissues. The proteolytic activity of FAP has been shown to support tumor growth and proliferation, making it a potential target for novel anticancer therapies, such as those by immune-based approaches.

Upregulated Expression of Indoleamine 2, 3-Dioxygenase in Primary Breast Cancer Correlates with Increase of Infiltrated Regulatory T Cells In Situ and Lymph Node Metastasis

IDO has been reported to induce immunotolerance and promote metastasis in solid malignancy, but the mechanisms involved were not fully understood. In this study, the expression of IDO in primary breast cancer was examined and the correlation between the expression levels of IDO and the densities of Foxp3+ Tregs in situ was studied. The IDO stably-expressing CHO cells(IDO/CHO) were generated to evaluate the induction of Foxp3+ Tregs after coculturing with CD3+ T cells in vitro. The IDO expression in cancer was higher than that in benign diseases both at RNA and protein levels. The IDO expression was significantly upregulated in tumors of more advanced stages and with more extensive lymph node metastasis, and displayed positive linear correlation with the density of Foxp3+ Tregs. We further demonstrated that CD4+CD25+CD127− Tregs could be amplified by coculturing CD3+ T cells with IDO/CHO cells in vitro which displayed increasing Foxp3 expression both at mRNA and protein levels. Our results implied that up-regulation of IDO in primary breast cancer may inhibit local immune surveillance and promote metastasis by favoring development and infiltration of Foxp3+ Tregs in the tumor microenvironment.