Jin Pu Yu

MiR-205 in cancer: An angel or a devil?

MicroRNAs (MiRNAs) are small non-coding RNAs that regulate their target genes expression at the post-transcriptional level. As accumulating properties of miR-205 have been identified, complex roles of miR-205 in tumor initiation and progression are emerging. MiR-205 acts either as a tumor suppressor through inhibiting proliferation and invasion, or as an oncogene through facilitating tumor initiation and proliferation, depending on the specific tumor context and target genes. In this review, we focus on the properties of miR-205 in cancers to shed light on better management of various fatal malignancies. Moreover, we discuss epigenetics that may account for the fluctuation of miR-205 expression. In addition, we sketch a network of miR-205 and its targets to further elucidate the mechanisms through which miR-205 exerts its multiple functions.

CD4+CD25+ Regulatory T Cells Decreased the Antitumor Activity of Cytokine-Induced Killer (CIK) Cells of Lung Cancer Patients

xa0CD4+CD25+ regulatory T cells (Tregs) have been shown to inhibit cytotoxic lymphocytes-mediated immune responses. Cytokine-induced killer (CIK) cells exert high impact on adoptive immunotherapeutic approaches. Therefore, the purpose of this report was to determine the effect of Tregs on CIK cell growth and CIK-induced cytotoxicity for inhibition of tumor growth in vivo as well as in vitro. After depletion of CD4+CD25+ cells before culture, the proliferation and cytotoxicity of CIK cells, which indicated in bromodeoxyuridine (BrdU) and lactic dehydrogenase (LDH) assays, were significantly increased. Depletion of CD4+CD25+ cells preculture also enhanced the suppression effect on the lung cancer cells inoculated in experimental animals. Blockage of glucocorticoid-induced tumor necrosis factor receptor (GITR) and transforming growth factor β1 (TGF-β1) by antibodies partially abrogated the suppressive effect of CD4+CD25+ cells on CIK. These results indicated that Tregs could inhibit the antitumor activity of CIK cells. The molecules TGF-β and GITR may contribute to the suppressive function of CD4+CD25+ cells.

Role of SOCS1 in tumor progression and therapeutic application

SOCS1, a prototype molecule of the SOCS family, was initially defined as a suppressor of cytokine signaling. The molecular mechanisms of SOCS1‐mediated functions have been subsequently identified by studies using gene knockout mice and gene silencing technology. As part of a negative feedback regulation, SOCS1 downregulates cytokine signaling through direct inhibition of the JAK tyrosine kinase and the signaling cascade of activated cytokine receptors, thereby attenuating cytokine‐initiated signal transduction. Moreover, other studies have demonstrated that SOCS1 also downregulates TLR signaling through direct and indirect mechanisms. Both cytokine receptor and TLR signaling pathways mediate important functions in survival, maturation and differentiation of various types of cells and in the regulation of immune function. Abnormal expression of SOCS1 in tumor cells has been detected in various human cancers, where it is associated with dysregulation of cytokine receptor and TLR signaling to promote cell transformation. Recent studies on the function of SOCS1 in tumor cells have revealed its novel role in carcinogenesis. In this review, we will focus on the mechanism of action of SOCS1 in both tumor cells and antigen‐presenting cells in the tumor microenvironment. The potential of using SOCS1 as a diagnostic marker and therapeutic target in tumor diagnosis, prognosis and treatment is discussed.

Combined Erlotinib and Cetuximab overcome the acquired resistance to epidermal growth factor receptors tyrosine kinase inhibitor in non-small-cell lung cancer

PurposeNon-small-cell lung cancer (NSCLC) cells with somatic mutations in epidermal growth factor receptors (EGFR) are initially susceptible to tyrosine kinase inhibitor (TKI); however, eventually resistance to TKI is developed in these cells, which leads to the failure of treatment. The most common mechanism of this acquired drug resistance is development of a secondary T790M mutation in EGFR. In this study, we investigated the effects of the combination of Erlotinib and Cetuximab on T790M and L858R mutation lung cancer cells lines (H1975), in the primary NSCLC cells with the T790M mutation and TKI-resistant EGFR mutations human tumor xenograft model (H1975).MethodsThe effects of these two agents on cell proliferation, apoptosis, and EGFR-dependent signaling were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, annexin V staining, and Western blotting. Sensitivity of EGFR inhibitors was detected in the primary tumor cell suspension and human tumor xenograft model (H1975).ResultsCompared with single-agent treatment, the combination of Cetuximab and Erlotinib increased apoptosis of EGFR TKI–resistant NSCLC cells (H1975), resulting in more pronounced growth inhibition on cell proliferation and significant inhibition of EGFR-dependent signaling.ConclusionsThese data suggest that treatment with a combination of Erlotinib and Cetuximab overcomes T790M-mediated drug resistance.

How do tumor stem cells actively escape from host immunosurveillance

Tumor stem cells (TSCs) are considered as the seeds in tumor development, metastasis and recurrence. Despite the various immunosurveillance mechanisms in the host, TSCs may possess the phenotypic and functional properties to evade host immunosurveillance and immune-mediated rejection in immunologically intact individuals. The mechanisms of TSC recognition and their consequent destruction are actively disturbed by various processes, including altered immunogenicity of TSCs, production of TSC-derived regulatory molecules, and interaction of TSCs with tumor-infiltrating immune cells. In addition to these TSC-mediated mechanisms, the diverse mesenchymal cells and cytokines in the tumor microenvironment are contribute to TSC immune escape. Recent mechanistic studies provide a more comprehensive understanding of TSCs in the biology, prevention, and therapy of solid tumors. This review will focus on the latest findings for mechanisms underlying TSCs escape from the attack of immune system.

IDO⁺ DCs and signalling pathways.

Dendritic cells (DCs) have traditionally been viewed as constituting an information management system that functions solely to integrate a diverse array of incoming signals, in order to induce immune reactivity. In recent years, however, there has been a shift towards viewing these cells as key regulators in the orchestration of immunological tolerance, with increasing recognition that they are capable of suppressing T-cell responses depending on signalling processes and localised biochemical conditions. Indoleamine 2,3-dioxygenase (IDO) competent (IDO⁺) DCs are a subset of human DCs which are programmed to a tolerogenic state and play a vital role in establishing and maintaining a tumour-suppressing milieu. The expression of IDO in these DCs represents a key mechanism responsible for inducing the tolerogenic state. However, the mechanisms by which IDO becomes dysregulated in this subset of DCs have not yet been described. In this review, the function of IDO⁺ DCs within the cancer-tolerogenic milieu, as well as the signals responsible for expression of IDO in this subset, will be discussed.

Interferon-λs: special immunomodulatory agents and potential therapeutic targets.

Interferon (IFN)-λs are a new addition to the old IFN family and share many similarities, such as antiviral and antiproliferative characteristics, with type I IFNs. IFN-λs also exhibit unique characteristics in immunomodulation. Accumulating studies have indicated the interactions between IFN-λs and immune cells, which lead to the regulation of the latter. IFN-λs can influence dendritic cells (DCs) and their product, IFN-λs-DCs, can then regulate the function of T cells. On the other hand, IFN-λs can also directly affect T cells through inhibition of the T helper 2 cell (Th2) responses. IFN-λs have varying immunomodulatory functions under different physiological conditions or in different organs and can inhibit tumor growth via regulation of the immune system. Diseases associated with IFN-λs include asthma, allergy, and systemic lupus erythematosus. In this review, we summarize the current knowledge of the biology of IFN-λs and their immunomodulatory function in relevant human diseases.

Efficacy of large doses of IL-2-activated human leukocyte antigen haploidentical peripheral blood stem cells on refractory metastatic renal cell carcinoma.

Traditional immunotherapy for patients with refractory metastatic renal cell carcinoma (RCC) is limited because the tumors themselves induce immunosuppression. The aim of this article was to evaluate the clinical efficacy of the infusion of a high dose of interleukin (IL)-2-activated allogeneic haploidentical peripheral blood stem cells (haplo-PBSCs) in patients with advanced intractable RCC. Ten advanced RCC patients and their haploidentical relatives, who were haplo-PBSC donors, were enrolled in this study. All patients accepted one cycle of activated haplo-PBSCs. The clinical and immunologic responses were evaluated. A range from 2.3 to 5.5×10(10) of activated haplo-PBSCs were harvested after exposure to recombinant human IL-2 (rhIL-2), along with a significant increase in the proportion of natural killer cells and activated lymphocytes (CD69+ and CD25+). Enhanced cytotoxicity of haplo-PBSCs for RCC was also observed. After treatment, 2 (2/10) cases of partial remission, 6 (6/10) cases of stable disease, and 2 (2/10) cases of progressive disease were identified in these 10 patients. The median progression-free survival of the 10 patients was 5.5 months (3-14 months). The adoptive transfusion of IL-2-activated haplo-PBSCs can induce sustained antitumor effects for advanced intractable RCC patients who have had no response to conventional immunotherapy.