Mu-Han Lü

Macrophages in Tumor Microenvironments and the Progression of Tumors

Macrophages are widely distributed innate immune cells that play indispensable roles in the innate and adaptive immune response to pathogens and in-tissue homeostasis. Macrophages can be activated by a variety of stimuli and polarized to functionally different phenotypes. Two distinct subsets of macrophages have been proposed, including classically activated (M1) and alternatively activated (M2) macrophages. M1 macrophages express a series of proinflammatory cytokines, chemokines, and effector molecules, such as IL-12, IL-23, TNF-α, iNOS and MHCI/II. In contrast, M2 macrophages express a wide array of anti-inflammatory molecules, such as IL-10, TGF-β, and arginase1. In most tumors, the infiltrated macrophages are considered to be of the M2 phenotype, which provides an immunosuppressive microenvironment for tumor growth. Furthermore, tumor-associated macrophages secrete many cytokines, chemokines, and proteases, which promote tumor angiogenesis, growth, metastasis, and immunosuppression. Recently, it was also found that tumor-associated macrophages interact with cancer stem cells. This interaction leads to tumorigenesis, metastasis, and drug resistance. So mediating macrophage to resist tumors is considered to be potential therapy.

CXCL12/CXCR4 axis promotes mesenchymal stem cell mobilization to burn wounds and contributes to wound repair

BACKGROUND Bone marrow-derived mesenchymal stem cells (BM-MSCs) play a crucial role in tissue repair. Their role in thermal burn wound regeneration and the relevant mechanism, however, is rarely studied. METHODS BM-MSCs from green fluorescent protein transgenic male mice were transfused to irradiated recipient female C57BL/6 mice. Twenty-one days later, the female mice were inflicted with burn wounds. The size of the burned area was measured by an in vivo fluorescence imaging system, and BM-MSC chemotaxis and epithelialization were estimated by fluorescence in situ hybridization and immunofluorescence technology. The expression of CXCL12 and CXCR4 in the wound margin was detected by enzyme-linked immunosorbent assay and immunohistochemistry. The importance of CXCL12/CXCR4 signaling in BM-MSC chemotaxis was further estimated by blocking CXCR4 in vivo and in vitro. RESULTS In vivo imaging results showed that BM-MSCs migrated to the injured margins. Fluorescence in situ hybridization and immunofluorescence technology revealed that Y chromosome-positive cells derived from green fluorescent protein transgenic mice were detected to be colocalized with keratin protein. Enzyme-linked immunosorbent assay revealed increased levels of CXCL12 and CXCR4 protein in the wound sites of BM-MSC-treated chimeric mice after burn. Immunohistochemistry also disclosed that CXCL12 levels were elevated at postburn day 7 compared with day 0. Furthermore, pretreatment of the BM-MSCs with the CXCR4 antagonist AMD3100 significantly inhibited the mobilization of BM-MSCs in vitro and in vivo, which attenuated wound closure. CONCLUSION BM-MSC migration to the burned margins promotes the epithelialization of the wound, and mobilization of BM-MSCs is mediated by CXCL12/CXCR4 signaling.

microRNA detection in feces, sputum, pleural effusion and urine: Novel tools for cancer screening (Review)

microRNAs (miRNAs) are short non-coding RNA sequences that play important roles in the regulation of gene expression. They have significant regulatory functions in basic cellular processes, including differentiation, proliferation and apoptosis. miRNAs are differentially expressed in tumors, compared with normal tissues. Importantly, miRNAs are also stable and abundantly present in body fluids and feces. The high reproducibility, sensitivity and specificity of miRNAs in body fluids and feces enable miRNAs to be used as potential molecular markers for cancer screening. An increasingly large number of research studies have reported the role of miRNAs in this field. In the present review, we focused mainly on the application of detecting miRNAs in stool, sputum, pleural effusion and urine, to detect colon, lung and urological cancers, highlighting the role of miRNAs in early diagnosis and prognosis.

miR-27b Represses Migration of Mouse MSCs to Burned Margins and Prolongs Wound Repair through Silencing SDF-1a

Background Interactions between stromal cell-derived factor-1α (SDF-1α) and its cognate receptor CXCR4 are crucial for the recruitment of mesenchymal stem cells (MSCs) from bone marrow (BM) reservoirs to damaged tissues for repair during alarm situations. MicroRNAs are differentially expressed in stem cell niches, suggesting a specialized role in stem cell regulation. Here, we gain insight into the molecular mechanisms involved in regulating SDF-1α. Methods MSCs from green fluorescent protein transgenic male mice were transfused to irradiated recipient female C57BL/6 mice, and skin burn model of bone marrow-chimeric mice were constructed. Six miRNAs with differential expression in burned murine skin tissue compared to normal skin tissue were identified using microarrays and bioinformatics. The expression of miR-27b and SDF-1α was examined in burned murine skin tissue using quantitative real-time PCR (qPCR) and immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA). The Correlation of miR-27b and SDF-1α expression was analyzed by Pearson analysis Correlation. miRNAs suppressed SDF-1α protein expression by binding directly to its 3′UTR using western blot and luciferase reporter assay. The importance of miRNAs in MSCs chemotaxis was further estimated by decreasing SDF-1α in vivo and in vitro. Results miR-23a, miR-27a and miR-27b expression was significantly lower in the burned skin than in the normal skin (p<0.05). We also found that several miRNAs suppressed SDF-1α protein expression, while just miR-27a and miR-27b directly bound to the SDF-1α 3′UTR. Moreover, the forced over-expression of miR-27a and miR-27b significantly reduced the directional migration of mMSCs in vitro. However, only miR-27b in burn wound margins significantly inhibited the mobilization of MSCs to the epidermis. Conclusion miR-27b may be a unique signature of the stem cell niche in burned mouse skin and can suppress the directional migration of mMSCs by targeting SDF-1α by binding directly to its 3′UTR.

Efficacy of Probiotic Supplementation Therapy for Helicobacter pylori Eradication: A Meta-Analysis of Randomized Controlled Trials.

Background Traditional Helicobacter pylori (H. pylori) eradication therapies have shown efficacies below 80% in several studies, and their use has been accompanied by antibiotic-related side effects. Some recent studies have reported that supplementing standard therapies with probiotics can improve the efficacy and tolerability of Helicobacter pylori eradication therapy. Objective To assess the effects of probiotic supplementation on the eradication rates and therapy-related adverse event rates of anti-Helicobacter pylori regimens. Methods We searched PubMed, Medline, the Cochrane Central Registry of Controlled Trials and the Chinese Biomedical Database for eligible randomized controlled trials published through July, 2015. Review Manager 5.3 was used for all statistical analyses. Results Thirteen randomized controlled trials involving a total of 2306 patients were included in our analysis. Intent-to-treat (ITT) analysis performed using a fixed-effects model (test for heterogeneity I2 = 45%) showed that the pooled relative risk (RR) of eradication was significantly higher in the probiotic supplementation group than in the control group [RR 1.15, 95% confidence interval (CI): 1.10–1.20, P<0.00001]. The incidence of total antibiotic-related side effects was lower in the probiotic supplementation group than in the control group, and the pooled RR (studies n = 9) was 0.71 (95% CI: 0.54–0.94, P = 0.02), as determined using a random-effects model (heterogeneity test I2 = 59%). Certain adverse events, such as nausea and vomiting (RR = 0.58, 95% CI 0.35–0.95, P = 0.03), diarrhea (RR = 0.51, 95% CI: 0.31–0.84, P = 0.008) and constipation (RR = 0.47, 95% CI: 0.28–0.80, P = 0.005), were reported at lower rates in the probiotic supplementation group than in the control group. Subgroup analysis showed that eradication rates were significantly improved in both adults (RR = 1.14, 95% CI: 1.09–1.19, P<0.00001) and children (RR = 1.24, 95% CI: 1.05–1.47, P = 0.01) in the probiotic supplementation group and that no regional differences between Europe (RR = 1.17, 95% CI: 1.09–1.24, P<0.00001) and Asia were present (RR = 1.14, 95% CI: 1.06–1.22, P = 0.0002). However, the total adverse event rate was not decreased in the adult group (RR = 0.80, 95% CI: 0.61–1.04, P = 0.1) or the Asian group (RR = 0.68, 95% CI: 0.39–1.18, P = 0.17). Subgroup analyses examining therapy regimens and treatment durations showed that probiotic supplementation increased eradication rates in the triple-therapy (RR = 1.18, 95% CI: 1.12–1.25, P<0.00001), seven-day treatment (RR = 1.21, 95% CI: 1.12–1.31, P<0.00001) and fourteen-day treatment (RR = 1.13, 95% CI: 1.06–1.20, P = 0.0002) groups. The incidence of antibiotic-related side effects was significantly reduced in all groups, with the exception of the quadruple-therapy subgroup (RR = 1.13, 95% CI: 0.60–2.13, P = 0.07) and the fourteen-day therapy subgroup (RR = 0.96, 95% CI 0.61–1.51, P = 0.86). Supplementation with Lactobacillus alone (RR = 1.24, 95% CI: 1.12–1.38, P<0.0001) or multi-strain probiotics (RR = 1.12, 95% CI 1.07–1.18, P<0.00001) was effective at improving H. pylori eradication rates. However, supplementation with Lactobacillus alone did not significantly decrease the overall incidence of side effects (RR = 0.61, 95% CI: 0.11–3.51, P = 0.58). Our study also showed that probiotic supplementation before, during or after H. pylori eradication therapy improved eradication rates, regardless of supplementation duration. Furthermore, probiotic supplementation during H. pylori treatment reduced the incidence of side effects. Conclusion Probiotic supplementation during anti-Helicobacter pylori treatment may be effective for improving H. pylori eradication rates, minimizing the incidence of therapy-related adverse events and alleviating most disease-related clinical symptoms. However, our results should be interpreted with caution because of the presence of heterogeneity across the trials included in this analysis.

hTERT-based therapy: a universal anticancer approach (Review).

Human telomerase reverse transcriptase (hTERT) has been identified as a major protein involved in aberrant cell proliferation, immortalization, metastasis and stemness maintenance in a majority of tumors, yet it has little or no expression in normal somatic cells. During the past few years, the development of hTERT-based therapies such as immunotherapy, suicide gene therapy and small-molecule interfering therapy have become critical and specific for eradicating all types of cancer. Here, current knowledge regarding hTERT and its involvement in various cancers and its role as a target of cancer therapies are reviewed. Additionally, hurdles to new cancer therapy development and new therapeutic opportunities are described, along with areas that require further investigation.

Multiple Antigenic Peptides of Human Heparanase Elicit a Much More Potent Immune Response against Tumors

Peptide vaccination for cancer immunotherapy requires an ideal immune response induced by epitope peptides derived from tumor-associated antigens (TAA). Heparanase is broadly expressed in various advanced tumors. Accumulating evidence suggests that heparanase can serve as a universal TAA for tumor immunotherapy. However, due to the low immunogenicity of peptide vaccines, an ideal immune response against tumors usually cannot be elicited in patients. To increase the immunogenicity of peptide vaccines, we designed three 4-branched multiple antigenic peptides (MAP) on the basis of the human leukocyte antigen (HLA)-A2–restricted cytotoxic T lymphocyte (CTL) epitopes of human heparanase that we identified previously as antigen carriers. Our results show that MAP vaccines based on the HLA-A2–restricted CLT epitopes of human heparanase were capable of inducing HLA-A2–restricted and heparanase-specific CTL in vitro and in mice. Moreover, compared with their corresponding linear peptides, heparanase MAP vaccines elicited much stronger lysis of tumor cells by activating CD8+ T lymphocytes and increasing the releasing of IFN-γ. However, these heparanase-specific CTLs did not lyse heparanase-expressing autologous lymphocytes and dendritic cells, which confirm the safety of these MAP vaccines. Therefore, our findings indicate that MAP vaccines based on CTL epitopes of human heparanase can be used as potent immunogens for tumor immunotherapy because of advantages such as broad spectrum, high effectiveness, high specificity, and safety. Cancer Prev Res; 4(8); 1285–95. ©2011 AACR.

Noninvasive and real-time monitoring of the therapeutic response of tumors in vivo with an optimized hTERT promoter

Telomerase is commonly recognized as an effective anticancer target. The human telomerase reverse transcriptase (hTERT), the rate‐limiting component of telomerase, is expressed in most malignant tumors, but it is not found in most normal somatic cells. Here, we report a real‐time and noninvasive method to monitor tumor response to a lentivirus‐based hTERT‐conditional suicidal gene therapy.

SDF-1/CXCR4 Axis Promotes MSCs to Repair Liver Injury Partially through Trans-Differentiation and Fusion with Hepatocytes

MSCs have become a popular target for developing end-stage liver therapies. In this study, two models of bone marrow chimeric mice were used to construct the liver failure models. Then it was found that MSCs can transdifferentiate into hepatocyte-like cells and these hepatocyte-like cells can significantly express albumin. Furthermore it was also found that MSCs can fuse with the hepatocytes and these cells had the proliferation activity. However, the percentage of transdifferentiation was significantly higher than fusion. So it was considered that MSCs which transdifferentiated into hepatocyte-likes cells played important roles for repairing the injuring liver function.

Strategies for Enhancing Vaccine-Induced CTL Antitumor Immune Responses

Vaccine-induced cytotoxic T lymphocytes (CTLs) play a critical role in adaptive immunity against cancers. An important goal of current vaccine research is to induce durable and long-lasting functional CTLs that can mediate cytotoxic effects on tumor cells. To attain this goal, there are four distinct steps that must be achieved. To initiate a vaccine-induced CTL antitumor immune response, dendritic cells (DCs) must capture antigens derived from exogenous tumor vaccines in vivo or autologous DCs directly loaded in vitro with tumor antigens must be injected. Next, tumor-antigen-loaded DCs must activate CTLs in lymphoid organs. Subsequently, activated CTLs must enter the tumor microenvironment to perform their functions, at which point a variety of negative regulatory signals suppress the immune response. Finally, CTL-mediated cytotoxic effects must overcome the tolerance induced by tumor cells. Each step is a complex process that may be impeded in many ways. However, if these steps happen under appropriate regulation, the vaccine-induced CTL antitumor immune response will be more successful. For this reason, we should gain a better understanding of the basic mechanisms that govern the immune response. This paper, based on the steps necessary to induce an immune response, discusses current strategies for enhancing vaccine-induced CTL antitumor immune responses.