Xingbin Hu

Apogossypolone, a novel inhibitor of antiapoptotic Bcl-2 family proteins, induces autophagy of PC-3 and LNCaP prostate cancer cells in vitro.

Limited treatment options are available for aggressive prostate cancer. Gossypol has been reported to have a potent anticancer activity in many types of cancer. It can increase the sensitivity of cancer cells to alkylating agents, diminish multidrug resistance and decrease metastasis. Whether or not it can induce autophagy in cancer cells has not yet been determined. Here we investigated the antiproliferative activity of apogossypolone (ApoG2) and (-)-gossypol on the human prostate cancer cell line PC3 and LNCaP in vitro. Exposure of PC-3 and LNCaP cells to ApoG2 resulted in several specific features characteristic of autophagy, including the appearance of membranous vacuoles in the cytoplasm and formation of acidic vesicular organelles. Expression of autophagy-associated LC3-II and beclin-1 increased in both cell lines after treatment. Inhibition of autophagy with 3-methyladenine promoted apoptosis of both cell types. Taken together, these data demonstrated that induction of autophagy could represent a defense mechanism against apoptosis in human prostate cancer cells.

Anti-HCV reactive volunteer blood donors distribution character and genotypes switch in Xi'an, China

HCV is prevailed in the world as well as in China. Blood transfusion is one of the most common transmission pathways of this pathogen. Although data of HCV infection character were reported during the past years, anti-HCV reactive profile of China donors was not fully clear yet. Furthermore, infection progress was found related to the HCV genotype. Different genotype led to different efficacy when interferon was introduced into HCV therapy. Here we provided character data of HCV infection in China blood donors from the year of 2000 to 2009. The infection rate in local donors was lower than general population and descended from 0.80% to 0.40% or so in recent years. About 83% HCV strains were categorized into genotypes 1b and 2a. But 1b subtype cases climbed and 2a subtype cases decreased. The current study threw more light on HCV infection of blood donors in China, at least in the Northern region.

A novel hepatitis C virus vaccine approach using recombinant Bacillus Calmette-Guerin expressing multi-epitope antigen

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. HCV infection is associated with high morbidity and has become a major problem in public health. Until now, there has been no effective prophylactic or therapeutic vaccine. BCG, a live vaccine typically used for tuberculosis prevention, has been increasingly utilized as a vector for the expression of recombinant proteins that will induce specific humoral and cellular immune responses. In this study, recombinant BCG (rBCG) was engineered to express a HCV multi-epitope antigen CtEm, and HLA-A2.1 transgenic mice were immunized with rBCG-CtEm. High levels of specific anti-HCV antibodies targeted to mimotopes of HVR1 were detected in the serum. HCV-specific lymphocyte proliferation assay, cytokine determination and cytotoxicity assay indicated that HCV epotope-specific cellular immune responses were elicited in vitro. The rBCG-CtEm immunization conferred protection against infection with the recombinant vaccinia virus (rVV-HCV-CNS) in vivo. These results suggest that rBCG expressing multi-epitope antigen may serve as an effective vaccine against HCV infection.

Hepatitis B virus genotypes and evolutionary profiles from blood donors from the northwest region of China

Hepatitis B virus (HBV) is prevalent in China and screening of blood donors is mandatory. Up to now, ELISA has been universally used by the China blood bank. However, this strategy has sometimes failed due to the high frequency of nucleoside acid mutations. Understanding HBV evolution and strain diversity could help devise a better screening system for blood donors. However, this kind of information in China, especially in the northwest region, is lacking. In the present study, serological markers and the HBV DNA load of 11 samples from blood donor candidates from northwest China were determined. The HBV strains were most clustered into B and C genotypes and could not be clustered into similar types from reference sequences. Subsequent testing showed liver function impairment and increasing virus load in the positive donors. This HBV evolutionary data for China will allow for better ELISA and NAT screening efficiency in the blood bank of China, especially in the northwest region.

Production and Characterization of Monoclonal Antibody Specific for NS3 Helicase of Hepatitis C Virus

Hepatitis C virus (HCV) infection is the major etiological agent of chronic hepatitis, which leads to liver cirrhosis and hepatocellular carcinomas. HCV NS3 helicase is a promising target of anti-virus therapy. In this report, we discuss a strategy to generate monoclonal antibodies (MAbs) of the HCV NS3 helicase, and investigate its potential characteristic. Our results showed the production of MAbs against NS3 helicase, which could specifically recognize the native NS3 helicase in transiently transfected cells in the immunofluorescence experiment. The resultant MAbs were used as the first antibody in Western blot analyses, and observed the specific band that defines the NS3 helicase. Likewise, one MAb could inhibit the NS3 helicase enzymatic activity distinctly in the NS3 helicase-mediated DNA-unwinding assay. To conclude, these antibodies may be useful to generate specific diagnostic tools for HCV infection and may also be developed for potential therapeutics.

Sca‐1+mesenchymal stromal cells inhibit splenic marginal zone B lymphocytes commitment through Caspase‐3

Mesenchymal stromal cells (MSCs) have been characterized as an important component of hematopoietic niche, which are capable of modulating the immune system through interaction with a wide range of immune cells. Marginal zone B cells, one main type of mature B lymphocytes, play a central role in eliciting antibody response against pathogens. However, how MSCs and its subpopulations regulate marginal zone B cells commitment is unknown yet. In this study, we assessed the contribution of Sca‐1+MSCs on marginal zone B cells commitment. Our results showed that Sca‐1+MSCs inhibit the commitment of marginal zone B lymphocytes. The inhibition was exerted through lowered Caspase‐3 expression. Furthermore, we found marginal zone B lymphocytes in spleen of Caspase‐3 knockout mice decreased and Caspase‐3 knockout Sca‐1+MSCs accounted for the MZB lymphocytes decrease. In conclusion, our investigation provided clues about Sca‐1+MSCs regulation on the commitment of marginal zone B cells through Caspase‐3 gene.

Sca1+ mesenchymal stromal cells inhibit graft-versus-host disease in mice after bone marrow transplantation

Mesenchymal stromal cells (MSCs) have therapeutic potential for the prevention and treatment of graft-versus-host disease (GVHD). However, MSCs comprise several subpopulations, which have not been individually assessed for their role in GVHD suppression. In this study, we assessed the immunosuppressive effect of bone-related Sca1(+) MSCs on acute GVHD in a MHC-mismatched mouse model of allogeneic hematopoietic stem cell transplantation (HCT). Our results showed that Sca1(+) MSCs decreased the severity of acute GVHD (aGVHD) and prolonged the survival period of allogeneic HCT recipients. This effect was exerted through lowered T lymphocyte infiltration in target organs and by inhibition of CD80/86 expression on host dendritic cells. Furthermore, the expression of cytotoxic T-lymphocyte antigen-4 (CTLA-4), a negative regulator of T cells, was elevated in the recipient splenocytes. In conclusion, bone-related Sca1(+) MSCs subpopulation suppressed GVHD and could be a novel treatment for acute GVHD.

Growth inhibition and apoptosis induction of human umbilical vein endothelial cells by apogossypolone.

AIMS AND BACKGROUND Prostate cancer is one of the most common malignant tumors in the male reproductive system, which causes the second most cancer deaths of males, and control of angiogenesis in prostate lesions is of obvious importance. This study assessed the effect of apogossypolone (ApoG2) on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs). SUBJECTS AND METHODS HUVECs were treated with different concentrations of ApoG2. The survival rate of HUVECs were determined by MTT assay. Utrastructural changes of HUVECs were assessed with transmission electron microscopy. Apoptosis in HUVECs was analyzed by flow cytometry and cell migration by Boyden chamber assay. Matrigel assays were used to quantify the development of tube-like networks. RESULTS ApoG2 significantly inhibited HUVEC growth even at 24 h (P<0.05). The inhibitory effect of ApoG2 is more obvious as the concentration and the culture time increased (P<0.05). These results indicate that ApoG2 inhibits the proliferation of HUVECs in a time- and concentration-dependent manner with increase of the apoptosis rate. Besides, ApoG2 reduced the formation of total pseudotubule length and network branches of HUVECs. CONCLUSIONS The results suggest that ApoG2 inhibits angiogenesis of HUVECs by growth inhibition and apoptosis induction.

Immune response to fused core protein of hepatitis C virus and truncated tetanus toxin peptides in mice

Because no vaccine or effective therapy is available, thousands of people with HCV have died in recent years. Cytotoxic T lymphocytes (CTLs) play a critical role in the host cellular immune response against HCV. CTL epitopes in HCV core protein have been identified and used in vaccine development. T helper epitopes could promote cytokine secretion and antibody production to fight HCV. Tetanus toxin, an immunogen with many T helper epitopes, was once used in HBV therapeutic vaccine design. Here, eukaryotic and prokaryotic expression vectors were constructed to express truncated fragments of tetanus toxin and core genes of HCV. HLAA2.1 transgenic mice were inoculated with a recombinant plasmid vehicle with these two heterogenic gene fragments, and this augmented the titres of antibody against HCV. Antigen-specific lymphocyte proliferation, Th1 and Th2 cytokine levels and the number of lysed cells were markedly increased in the combined immunization group compared to controls. These findings provide new insights into a potential role for T helper epitopes from tetanus toxin combined with protein from the HCV core gene, which has numerous CTL epitopes. This design strategy may aid in the development of new vaccines against HCV.

Inhibitory activity of apogossypol in human prostate cancer in vitro and in vivo.

Apogossypol, a gossypol derivative, is a novel small-molecule inhibitor of the Bcl-2 family proteins and has been demonstrated to have anti-tumor activities. Prostate cancer is the most common malignancy in males, for which chemotherapy is the usual treatment option in clinical practice. The aim of the present study was to investigate the growth inhibitory effects of apogossypol on prostate cancers in vitro and in vivo. An MTT assay and a colony formation assay were used to assess the anti-survival and anti-proliferation effects of apogossypol in LNCaP cells. Immunofluorescence was performed in order to detect the expression levels of apoptosis-associated proteins in xenograft tumors following apogossypol treatment. Apogossypol exerted strong anti-tumor effects on LNCaP cells in a dose-dependent manner. Furthermore, immunofluorescence revealed that apogossypol inhibited the growth and proliferation of prostate cancer cells by downregulating Bcl-2 protein expression and activating caspase-3 and -8. In addition, the in vivo study indicated that apogossypol significantly inhibited tumor growth in a dose-dependent manner with reduced toxicity compared with gossypol. In conclusion, the present study indicated that apogossypol effectively inhibited the growth and proliferation of prostate cancer cells and may be a potential agent for prostate cancer therapy.