Publications (7)22.31 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Epidemiological studies show a positive correlation between the air levels of fine particulate matter (PM2.5 ) and cardiovascular disorders, but how PM2.5 affects cardiomyocytes has not been studied in great deal. The aim of the present study was to obtain an insight into the links among intracellular levels of reactive oxygen species (ROS), apoptosis and mitogen-activated protein kinases (MAPKs) in rat cardiac H9c2 cells exposed to PM2.5 . H9c2 cells were incubated with PM2.5 at 100-800 µg ml(-1) to evaluate the effects of PM2.5 on cell viability, cell apoptosis, intracellular levels of ROS and expression of apoptosis-related proteins as well as activation of MAPKs. PM2.5 decreased cell viability, increased the cell apoptosis rate and intracellular ROS production in a concentration-dependent manner. PM2.5 decreased the Bcl-2/Bax ratio and increased cleaved caspase-3 levels. A Western blots study showed up-regulation of phosphorylated MAPKs including extracellular signal-regulated protein kinases (ERKs), c-Jun NH2 -terminal kinases (JNKs) and p38 MAPK in the PM2.5 -treated cells. The p38 MAPK inhibitor SB239063 attenuated whereas the ERKs inhibitor PD98059 augmented the effects of PM2.5 on apoptosis and the expression of related proteins. In conclusion, PM2.5 decreases cell viability and increases apoptosis by enhancing intracellular ROS production and activating the MAPKs signaling pathway in H9c2 cells. The MAPKs signaling pathway could be a new promising target for clinical therapeutic strategies against PM2.5 -induced cardiac injury. Copyright © 2015 John Wiley & Sons, Ltd.
- [Show abstract] [Hide abstract] ABSTRACT: Remote ischemic preconditioning is often performed by limb ischemic preconditioning (LIPC), which has been demonstrated to be beneficial to various cells, including endothelial cells. The mechanisms underlying the protection have not been well clarified. The present study was designed to observe the effects of sera derived from rats after LIPC on human umbilical vein endothelial cells (HUVECs) injured by hydrogen peroxide (H2O2) -induced oxidative stress and explore the involvement of redox state in the protection. Incubation with 1 mM H2O2 for 2 h induced a significant reduction in HUVECs' viability with increased production of malondialdehyde (MDA) and reactive oxygen species (ROS). Preincubation with early preconditioning serum (EPS) or delayed preconditioning serum (DPS) derived from rats subjected to LIPC alleviated these changes. Both EPS and DPS increased the nuclear translocation of transcription factor nuclear factor E2-related factor 2 (Nrf2) and the expression of antioxidases. The protective effects of EPS and DPS were blocked neither by MEK/ERK inhibitors U0126 nor by PI3K/Akt inhibitors LY294002. In conclusion, the present study provides the evidence that LIPC protects the HUVECs from H2O2-induced injury by, at least partially, enhancement of Nrf2 translocation and upregulation of antioxidases via signaling pathways independent of MEK/ERK and PI3K/Akt.
- [Show abstract] [Hide abstract] ABSTRACT: Multidrug resistance (MDR) is a major hurdle in the treatment of cancer. Research indicated that the main mechanisms of most cancers included so-called "pump" (P-glycoprotein, P-gp) and "non-pump" (apoptosis) resistance. Identification of novel signaling molecules associated with both P-gp and apoptosis will facilitate the development of more effective strategies to overcome MDR in tumor cells. Since the proto-oncogene c-fos has been implicated in cell adaptation to environmental changes, we analyzed its role in mediating "pump" and "non-pump" resistance in MCF-7/ADR, an adriamycin (ADR)-selected human breast cancer cell line with the MDR phenotype. Elevated expression of c-fos in MCF-7/ADR cells and induction of c-fos by ADR in the parental drug-sensitive MCF-7 cells suggested a link between c-fos and MDR phenotype. Down-regulation of c-fos expression via shRNA resulted in sensitization of MCF-7/ADR cells to chemotherapeutic agents, including both P-gp and non-P-gp substrates. Further results proved that c-fos down-regulation in MCF-7/ADR cells resulted in decreased P-gp expression and activity, enhanced apoptosis, and altered expression of apoptosis-associated proteins (i.e., Bax, Bcl-2, p53 and PUMA). All above facts indicate that c-fos is involved in both P-gp- and anti-apoptosis-mediated MDR of MCF-7/ADR cells. Based on these results, we propose that c-fos may represent a potential molecular target for resistant cancer therapy, and suppressing c-fos gene expression may therefore be an effective means to temper breast cancer cell's MDR to cytotoxic chemotherapy. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.
- [Show abstract] [Hide abstract] ABSTRACT: Multidrug resistance (MDR) is a major obstacle that hinders the efficacy of chemotherapy in many human malignancies. PHⅡ-7 is a derivative of indirubin, which is designed and synthesized by our laboratory. Our preliminary work indicates its potent antitumor activities in vitro and in vivo. Furthermore, based on the model of MDR cell line, we found its powerful effect in inhibiting the expression of P-glycoprotein (P-gp) and killing multidrug-resistant (MDR) cells. However, the detailed mechanism of PHⅡ-7 remains to be explored. Reactive Oxygen Species are known for high reactive activity as they possess unmatched electrons. In this study, we showed that PHⅡ-7 generated equal reactive oxygen species in parental K562 and its counterpart MDR K562/A02 cells. Pre-incubation with thiol antioxidants glutathione or N-acetyl-cysteine(NAC) almost abolished the cytotoxicity of PHⅡ-7. Moreover, NAC abrogated DNA damage, cell cycle arrests and apoptosis induced by PHⅡ-7. Our results collectively indicated that reactive oxygen species production induced by PHⅡ-7 contributed to both apoptosis and cell cycle arrets in MDR K562/A02 cells, thus extending our prior related findings. Notably, JNK phosphorylation was induced by PHⅡ-7 and pre-incubated of K562/A02 cells with NAC or inhibitor of JNK(SP006125) eliminated P-gp downregulation. Taken together, our results provide a detailed biochemical basis for further clinical application of PHⅡ-7.
- [Show abstract] [Hide abstract] ABSTRACT: Chemotherapeutic drugs can enhance an immune response of the host against the tumor in addition to killing cancer cells by direct cytotoxicity. So the combination of chemotherapy and immunotherapy is a promising approach for eliminating tumors, particularly in advanced stages. A strategic medication is to use a bispecific antibody format which is capable of recruiting polyclonal T cells around antibody-target-expressing tumor cells. Recently, we have constructed a bispecific antibody, antiCD3-antiCD19, in a diabody configuration. In this study, we measured B7 family members B7.1 (CD80) and B7.2 (CD86) expressed on a CD19+ human leukemia cell line, Nalm-6, stimulated by cytosine arabinoside (Ara-C). We found that a low concentration of Ara-C could up-regulate CD80 expressed on CD19+ Nalm-6 cells. The cytotoxicity of T lymphocytes against Nalm-6 cells in vitro and in vivo mediated by antiCD3×antiCD19 diabody with or without low dose of Ara-C was compared. The combination of antiCD3×antiCD19 diabody and Ara-C showed the greatest effectiveness in enhancing the cytotoxicity of T cells against the tumor cells in vitro and in vivo. Activated T cells expressed higher levels of CD25 and CD69 and released more interleukin 2 (IL-2). Both perforin/granzyme B system and Fas/FasL pathway were involved in the diabody-induced T-cell cytotoxicity. Moreover, the activated T cells could up-regulate ICAM-3 expression on Nalm-6 cells, and inhibition of LFA-1-ICAM-3 interaction impaired cytotoxicity of T cells. It was noted that Ara-C could up-regulate CD80 expressed on 2 of 5 specimens of acute B lymphoblastic leukemia (B-ALL) patient-derived cells. Cytotoxicity of T cells against these two patient-derived cells was enhanced in the presence of antiCD3×antiCD19 diabody. These findings indicate that treatment strategy using both cytotoxic lymphocyte-based immunotherapy and chemotherapy may have synergistic effects.
- [Show abstract] [Hide abstract] ABSTRACT: Multidrug resistance (MDR) is a major impediment to the effective chemotherapy of many human malignancies, and novel MDR reversal agents are desirable for combination therapy to reduce MDR, enhance anti-tumor activity and reduce side effects. Overexpression of P-glycoprotein (P-gp) is the most prevalent cause of MDR in cancer tissues, and resistance to apoptosis is a common characteristic for the multidrug resistant cancer cells. Our group has synthesized a novel potent anti-tumor indirubin derivative, PHII-7. In this study, MCF-7/ADR cells, an adriamycin (ADR)-selected human breast tumor cell line with the MDR phenotype, were used to investigate the anticancer properties of this novel indirubin derivative. Cytotoxicity and apoptosis assays showed that PHII-7 significantly inhibited cell growth, induced apoptosis, potentiated ADR cytotoxicity and restored chemotherapy sensitivity in the MDR cancer cells. Further studies indicated that by down-regulation of P-gp expression, PHII-7 partially inhibited P-gp efflux pump function and increased intracellular accumulation of Rhodamine 123, a P-gp substrate. These results provide a biochemical basis for possible clinical application of PHII-7 alone or in combination with conventional antineoplastic agents in the treatment MDR tumors.
- [Show abstract] [Hide abstract] ABSTRACT: Here we constructed and produced a recombinant human 4-1BB ligand (4-1BBL)/anti-CD20 fusion protein and examined its antitumor activity, alone and in combination with an anti-CD3/anti-CD20 bispecific diabody. The 4-1BBL/anti-CD20 fusion protein retained both the costimulatory activity of 4-1BBL on T cells and the tumor targeting ability of CD20 antibody on B cells. The fusion protein bound as efficiently to 4-1BB- and CD20-positive cells as its respective parental antibodies, and was capable of cross-linking human T lymphocytes and CD20-positive tumor cells. Combination treatment with 4-1BBL/anti-CD20 fusion protein and anti-CD3/anti-CD20 diabody led to significantly increased T-cell cytotoxicity to human B-lymphoma cells in vitro and drastically more potent tumor inhibitory activity in vivo in xenografted B-cell lymphoma in severe combined immunodeficiency disease mice. Mechanistic studies revealed that the combination treatment remarkably inhibited apoptosis of human peripheral blood lymphocytes, accompanied by upregulation of Bcl-XL and Bf1-1, perforin and granzyme B mRNA, and increased interleukin-2 production. Taken together, these results suggest that targeted delivery of 4-1BBL to the tumor site, when combined with anti-CD3/anti-CD20 diabody, could strongly potentiate the antitumor activity of the diabody, thus may have significant clinical application in the treatment of human CD20-positive B-cell malignancies.
Shanxi Medical University
Yangkü, Shanxi Sheng, China
- Department of Pharmacology