Qian Huang

Renji Hospital, Shanghai, Shanghai Shi, China

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Publications (66)220.42 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Dopaminergic (DA) neuron-like cells obtained through direct reprogramming of primary human fibroblasts offer exciting opportunities for treatment of Parkinson's disease. A significant obstacle is the low efficiency of conversion during the reprogramming process. Here, we demonstrate that the suppression of p53 significantly enhances the efficiency of transcription factor-mediated conversion of human fibroblasts into functional dopaminergic neurons. In particular, blocking p53 activity using a dominant-negative p53 (p53-DN) in IMR90 cells increases the conversion efficiency by 5-20 fold. The induced DA neuron-like cells exhibit dopamine neuron-specific gene expression, significant dopamine uptake and production capacities, and enables symptomatic relief in a rat Parkinson's disease model. Taken together, our findings suggest that p53 is a critical barrier in direct reprogramming of fibroblast into dopaminergic neurons.
    Science China. Life sciences. 08/2014;
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    ABSTRACT: Pancreatic cancer is one of the most lethal human cancers, and radiotherapy is often implemented for locally advanced pancreatic ductal adenocarcinoma. Tumor cell repopulation is a major challenge in treating cancers after radiotherapy. In order to address the problem of tumor repopulation, our previous studies have demonstrated that dying cells stimulate the proliferation of living tumor cells after radiotherapy. In particular, dying cells undergoing apoptosis also activate survival or proliferation signals and release growth factors to surrounding living cells. In the present study, we used an in vitro model to examine the possible mechanisms for dying cell stimulated tumor repopulation in pancreatic cancer. In this model, a small number of living, luciferase-labeled pancreatic cancer cells (reporter) were seeded onto a layer of a much larger number of irradiated, unlabeled pancreatic cancer cells and the growth of the living cells was measured over time as a gage of tumor repopulation. Our results indicate that irradiated, dying Panc1 feeder cells significantly stimulated the proliferation of living Panc1 reporter cells. Importantly, we identified that the percentage of apoptotic cells and the cleavage of caspases 3 and 7 and protein kinase Cδ (PKCδ) were increased in irradiated Panc1 cells. We presumed that caspases 3 and 7 and PKCδ as integral mediators in the process of dying pancreatic cancer cell stimulation of living tumor cell growth. In order to demonstrate the importance of caspases 3, 7 and PKCδ, we introduced dominant-negative mutants of caspase 3 (DN_C3), caspase 7 (DN_C7), or PKCδ (DN_PKCδ) into Panc1 cells using lentiviral vectors. The stably transduced Panc1 cells were irradiated and used as feeders and we found a significant decrease in the growth of living Panc1 reporter cells when compared with irradiated wild-type Panc1 cells as feeders. Moreover, the role of PKCδ in the growth stimulation of living tumor cells was further confirmed using a pan PKC inhibitor GF109203x and a specific PKCδ inhibitor, rottlerin. Additionally, we found significantly increased phosphorylation of Akt, p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase/stress-activated protein kinase (JNK1/2) in the irradiated Panc1 cells. Mechanistically, PKCδ cleavage was attenuated in both DN_C3 and DN_C7 transduced Panc1 cells, and both Akt and p38 MAPK phosphorylation were attenuated in DN_PKCδ transduced Panc1 cells following radiation. Thus, this report suggests a novel finding that cellular signaling caspase 3/7-PKCδ-Akt/p38 MAPK is crucial to the repopulation in Panc1 cells after radiotherapy.
    Molecular oncology. 08/2014;
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    ABSTRACT: Oncolytic viruses have recently received widespread attention for their potential in innovative cancer therapy. Many telomerase promoter-regulated oncolytic adenoviral vectors retain E1A and E1B. However, the functions of E1A and E1B proteins in the oncolytic role of replication-competent adenovirus (RCAd) and RCAd enhanced transduction of replication defective adenoviruses (RDAd) have not been addressed well. In this study, we constructed viruses expressing E1A alone, E1A plus E1B-19 kDa, and E1A plus E1B-19 kDa/55 kDa. We then tested their roles in oncolysis and replication of RCAd as well as their roles in RCAd enhanced transfection rate and transgene expression of RDAd in various cancer cells in vitro and in xenografted human NCI-H460 tumors in nude mice. We demonstrated that RCAds expressing E1A alone and plus E1B-19 kDa exhibited an obvious ability in replication and oncolytic effects as well as enhanced RDAd replication and transgene expression, with the former showed more effective oncolysis, while the latter exhibited superior viral replication and transgene promotion activity. However, RCAd expressing both E1A and E1B-19kDa/55kDa was clearly worst in all these abilities. The effects of E1A and E1B observed through using RCAd were further validated by using plasmids expressing E1A alone, E1A plus E1B-19kDa, and E1A plus E1B-19kDa/55kDa proteins. Our study provided evidence that E1A was essential for inducing replication and oncolytic effects of RCAd as well as RCAd enhanced RDAd transduction, and expression of E1B-19kDa other than E1B-55kDa could promote these effects. E1B-55kDa is not necessary for the oncolytic effects of adenoviruses and somehow inhibits RCAd-mediated RDAd replication and transgene expression.
    Cancer biology & therapy 07/2014; 15(10). · 3.29 Impact Factor
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    ABSTRACT: Metastatic melanoma often relapses despite cytotoxic treatment, so the understanding of melanoma tumor repopulation is crucial to improving our current therapies. In this study, we aim to define the role of caspase 3 in melanoma tumor growth after cytotoxic therapy. We examined a paradigm-changing hypothesis that dying melanoma cells undergoing apoptosis during cytotoxic treatment activate paracrine signaling events that promote the growth of surviving tumor cells. We propose that caspase 3 plays a key role in the initiation of the release of signals from dying cells to stimulate melanoma tumor growth. We created a model for tumor cell repopulation in which a small number of luciferase-labeled, untreated melanoma cells are seeded onto a layer of a larger number of unlabeled, lethally treated melanoma cells. We found that dying melanoma cells significantly stimulate the growth of living melanoma cells in vitro and in vivo. Furthermore, we observed that caspase 3 gene knockdown attenuated the growth-stimulating effect of irradiated, dying cells on living melanoma cell growth. Finally, we showed that caspase 3-mediated dying melanoma cell stimulation of living cell growth involves secreted PGE2. Our study therefore suggests a counterintuitive strategy to inhibit caspase 3 for therapeutic gain in melanoma treatment.Journal of Investigative Dermatology accepted article preview online, 16 January 2014. doi:10.1038/jid.2014.18.
    Journal of Investigative Dermatology 01/2014; · 6.19 Impact Factor
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    ABSTRACT: The death of all the cancer cells in a tumor is the ultimate goal of cancer therapy. Therefore, much of the current effort in cancer research is focused on activating cellular machinery that facilitates cell death such as factors involved in causing apoptosis. However, recently, a number of studies point to some counterintuitive roles for apoptotic caspases in radiation therapy as well as in tissue regeneration. It appears that a major function of apoptotic caspases is to facilitate tissue regeneration and tumor cell repopulation during cancer therapy. Because tumor cell repopulation has been shown to be important for local tumor relapse, understanding the molecular mechanisms behind tumor repopulation would be important to enhance cancer radiotherapy. In this review, we discuss our current knowledge of these potentially paradigm-changing phenomena and mechanisms in various organisms and their implications on the development of novel cancer therapeutics and strategies.
    Seminars in radiation oncology 10/2013; 23(4):288-95. · 4.32 Impact Factor
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    ABSTRACT: Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by poor prognosis. Currently, no reliable markers have been identified as having a predictive role for the prognosis of TNBC patients. In this study, 119 breast cancer samples, including 31 TNBC and 89 non-TNBC subtypes, were collected. The protein levels of cleaved caspase-3 (CC3), aldehyde dehydrogenase 1 (ALDH1), cyclooxygenase-2, Ki-67, H2A histone family member X, and phosphorylated protein kinase B protein were measured by immunohistochemical staining. The percentage of positive CC3 (P = .017), ALDH1 (P = .015), Ki-67 (P = .001), and H2A histone family member X (P = .016) staining was significantly higher in TNBC than in non-TNBC cases. Positive CC3 and ALDH1 staining significantly correlated with poor prognosis of breast cancer, the TNBC subtype and non-TNBC subtype. Positive cyclooxygenase-2 expression significantly correlated with the survival of patients with TNBC. Multivariate analysis demonstrated that CC3 and ALDH1 are independent prognostic factors for BC and non-TNBC. ALDH1 is a prognostic marker for TNBC patients.
    Human pathology 07/2013; · 3.03 Impact Factor
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    ABSTRACT: The expression of vascular endothelial growth factor (VEGF) is regulated by microenvironmental factors within the tumors, such as hypoxia, free radicals, pH imbalance and nutrient deficiency. The purpose of this study was to observe VEGF activity in tumor cells under different stress conditions. A plasmid was generated, consisting of green fluorescent protein (GFP) fused to a 1,217-bp sequence, which was located downstream and upstream of the transcriptional start site of VEGF, respectively. The plasmid was stably transfected into 4T1 mouse breast carcinoma cells. Cells were cultured in a medium with nitric oxide (NO) donor sodium nitroprusside (SNP), hypoxia-mimetic agent deferoxamine mesylate (DFX), H2O2, absence of serum and lowered or elevated pH, or were heat-shocked, followed by measurement of VEGF activity by reverse transcription polymerase chain reaction (RT-PCR) and ELISA. Hypoxia, SNP and H2O2 led to increments of VEGF mRNA and protein expression, as well as of GFP expression. The pH alterations, serum deprivation and heat shock reduced VEGF mRNA expression, but had little effect on GFP expression. The results demonstrated that VEGF expression may be influenced by a number of microenvironmental factors and these factors may play important roles in regulating VEGF expression during tumorigenesis.
    Biomedical reports. 07/2013; 1(4):539-544.
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    ABSTRACT: Resistance to chemotherapy and endocrine therapy is a serious obstacle in the treatment of breast cancer. Highly specific biomarkers for predicting therapeutic resistance have not yet been identified. In this study, the amounts of aldehyde dehydrogenase 1, cleaved caspase 3, cyclooxygenase 2, phosphorylated Akt, Ki-67, and H2AX proteins were measured by immunohistochemical staining in 113 breast cancer tissues, and their predictive ability for therapeutic resistance was investigated. The patients were receiving chemotherapy (n = 30), endocrine therapy (n = 22), or combined chemotherapy and endocrine therapy (n = 61). Expression of aldehyde dehydrogenase 1, cleaved caspase 3, and cyclooxygenase 2 correlated significantly with a higher relapse rate (P < .05 or P < .01) and shorter survival (P < .01 or P < .001) in triple-negative patients receiving chemotherapy. In addition, cyclooxygenase 2 expression was an independent predictor of a poor prognosis (P < .05). On the other hand, aldehyde dehydrogenase 1 expression correlated significantly with shorter survival in patients receiving combined therapy (P < .01) but showed no association with relapse. No correlation was observed between Ki-67, phosphorylated Akt, and H2AX expression and survival or relapse in any group of patients. These data suggest that aldehyde dehydrogenase 1, cleaved caspase 3, and cyclooxygenase 2 are useful markers for therapeutic resistance in breast cancer.
    Human pathology 02/2013; · 3.03 Impact Factor
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    ABSTRACT: BACKGROUND: An adenovirus that expresses both interleukin (IL)-12 and granulocyte-macrophage colony-stimulating-factor (GM-CSF) has been proven to be very effective in treating several tumors, but causes serious normal tissue toxicities. METHODS: In this study, a novel adenoviral vector was constructed by placing the human GM-CSF gene under the control of the CMV-IE promoter and human IL-12 gene under the control of heat shock protein 70B gene promoter. Both hGM-CSF and hIL-12 expressions in virus-infected tumor cells were analyzed in vitro and in vivo when underlying single or multiple rounds of hyperthermia. RESULTS: We observed constitutive high expression of human GM-CSF and heat-induced expression of human IL-12 after a single round of hyperthermia post viral infection. The heat-induced hIL-12 expression exhibited a pulse-like pattern with a peak at 24 hrs followed by a decline 48 hrs post heat stress. Repeated heat treatment was more effective in inducing hIL-12 expression than a one-time heat treatment. Interestedly, we also observed that constitutive expression of hGM-CSF could be stimulated by heat stress in tested tumor cells. CONCLUSION: Our study provided a novel strategy for combined gene therapy that allows constitutive expression of a non-toxic gene such as GM-CSF and heat-induced expression of a toxic gene such as IL-12. In addition, our study also showed that hyperthermia can be used to trigger gene expression in temporal and special manner.
    Journal of Experimental & Clinical Cancer Research 01/2013; 32(1):5. · 3.07 Impact Factor
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    ABSTRACT: Tumor growth after radiotherapy is a commonly recognized cause of therapeutic failure. In this way, we examined tumor cell growth after radiotherapy by establishing a cancer cell growth model in vitro. We accomplished this model by seeding non-irradiated firefly luciferase2 and green fluorescent protein fusion gene (Fluc) labeled living cancer reporter cells onto a feeder layer of irradiated cancer cells. The living tumor cell growth was monitored by bioluminescence imaging. The living reporter cells grew faster when seeded onto lethally irradiated feeder cells than when seeded onto non-irradiated feeder cells or when seeded in the absence of feeder cells. We found that the expression levels of the Shh and Gli1 proteins, both of which are critical proteins in Sonic hedgehog (SHH) signaling, were increased after irradiation and that this expression was positively correlated with reporter cell growth. Moreover, the dying cell stimulation of living tumor cell growth was enhanced by the addition of SHH signaling agonists and inhibited by SHH signaling antagonists. SHH agonists also enhanced reporter cell growth in the absence of irradiated feeder cells, suggesting this mechanism plays a role in feeder cell growth stimulation. Given these results, we conclude that SHH signaling activation plays an important role during tumor repopulation after radiotherapy.
    PLoS ONE 01/2013; 8(6):e65032. · 3.53 Impact Factor
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    ABSTRACT: Purpose. Currently, choroidal melanoma is chemoresistant and there is no routine adjuvant chemotherapy for it. We investigated whether pigment epithelium-derived factor (PEDF) and its triple phosphomimetic mutants could more efficiently suppress melanoma tumor growth and metastasis, as well as how the triple phosphomimetic mutants act as antitumor agents. Methods. Phosphomimetic mutants of PEDF were constructed by site mutagenesis. Lentiviruses carrying wild type (WT) PEDF, S24E114E227A (EEA)-PEDF, and S24E114E227E (EEE)-PEDF were produced in 293 fast-growing, highly transfectable (FT) cells and used to infect human choroidal melanoma cell line (OCM-1). The growth, migration, invasion and metastasis abilities of OCM-1 cells expressing WT-PEDF, EEA-PEDF or EEE-PEDF were investigated in vitro and in vivo, while the underlying mechanism of PEDF phosphomimetic mutants were investigated via Western blotting. Results. OCM-1 cells infected with lentiviruses carrying WT-PEDF, EEA-PEDF, and EEE-PEDF displayed reduced proliferation, migration and invasion abilities, and were more prone to apoptosis. Cell media containing WT-PEDF, EEA-PEDF, or EEE-PEDF protein inhibited the tube forming capacity of human umbilical vein endothelial cells (HUVEC) in vitro. OCM-1 cells expressing WT-PEDF, EEA-PEDF, or EEE-PEDF displayed significantly reduced tumor growth and metastasis in the melanoma xenograft of nude mice models, with the PEDF mutants displaying much stronger effects than the wild type. The antitumor effects of PEDF are associated with the inhibition of VEGF and nuclear factor kappa-B (NF-κB) expression, as well as further inhibition of Akt phosphorylation. Conclusions. The phosphomimetic mutants of PEDF showed enhanced anti-melanoma activity by directly affecting tumor cells and indirectly affecting angiogenesis. These findings encourage the development of PEDF mutants as innovative anticancer agents.
    Investigative ophthalmology & visual science 09/2012; 53(11):6793-802. · 3.43 Impact Factor
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    ABSTRACT: Pancreatic cancer is a disease with poor prognosis and high mortality. To identify novel molecular markers that could predict the prognosis of pancreatic ductal adenocarcinoma, a total of 114 pancreatic ductal adenocarcinomas and 99 peritumoral tissues were collected. Protein levels of cleaved caspase-3, cyclin D1, epidermal growth factor receptor and Her-2 (human epidermal growth factor receptor 2) were measured by immunohistochemistry. Molecular abnormalities of cyclin D1/q11, Her-2/q17, and epidermal growth factor receptor/p7 were detected using fluorescence in situ hybridization. Results demonstrated that the protein levels of cleaved caspase-3, epidermal growth factor receptor, Her-2, and cyclin D1 were significantly higher in pancreatic ductal adenocarcinoma than that in peritumoral tissues (P = .000). Significantly more amplifications of epidermal growth factor receptor, Her-2, and cyclin D1 were observed in pancreatic ductal adenocarcinoma patients than in peritumoral tissues. In addition, 51.8% of pancreatic ductal adenocarcinoma tumors showed polysomy 7, 50% showed polysomy 11, and 40.4% showed polysomy 17. However, no polysomy was observed in peritumoral tissues. Her-2 amplification and polysomy 17 significantly correlated with poor prognosis of pancreatic ductal adenocarcinoma (P = .008 and P = .005, respectively). Interestingly, only cleaved caspase-3 protein level significantly correlated with poor survival in pancreatic ductal adenocarcinoma patients (P = .000). We also observed significant correlations of cleaved caspase-3 level with epidermal growth factor receptor, Her-2, and cyclin D1 protein levels and the molecular abnormalities of Her-2 and cyclin D1. Conclusively, cleaved caspase-3 level is an ideal biomarker to predict prognosis in pancreatic ductal adenocarcinoma patients and might be a better target for pancreatic ductal adenocarcinoma treatment than epidermal growth factor receptor/Her-2 and cyclin D1.
    Human pathology 08/2012; · 3.03 Impact Factor
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    ABSTRACT: In this study, we investigated p53 and p16 deletions, and chromosome 9 and 17 amplifications in pancreatic ductal adenocarcinoma (PDAC), and further analyzed their associations with clinical characteristics and prognosis of PDAC. A total of 32 PDAC and 23 peritumoral tissues were collected. Molecular abnormalities of CEP9/p16 and CEP17/p53 were detected using Fluorescence in situ hybridization (FISH). Deletions of p16 and p53 were detected in 50 % and 65.7 % of PDAC, respectively. Polysomy 9 and 17 were identified in 75 % and 71.8 % of PDAC, respectively. No p16 and p53 deletion, polysomy 9 and 17 were identified in peritumoral tissues. We also observed significant correlations of p16 deletion, polysomy 9 and 17 with shorter survival of PDAC. P16 deletion, polysomy 9 and 17 are predictive markers for poor prognosis of PDAC patients, but p53 deletion is not associated with the clinical characteristics and prognosis of PDAC.
    Pathology & Oncology Research 07/2012; · 1.56 Impact Factor
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    ABSTRACT: One of the key issues in cancer radiotherapy research is to sensitize tumor cells to the cell killing effects of ionizing radiation while leaving normal tissues intact. One potential approach to achieve this is through tumor-specific targeting of DNA repair genes. In this study, we engineered a replication-deficient adenovirus encoding a mini shRNA gene targeted to the DNA-PKcs gene, which is involved in double strand break DNA repair, and evaluated its anti-tumor efficacy in combination with radiotherapy. Our shRNA-encoding adenovirus showed significant efficacy in down-regulating the levels of the DNA-PKcs protein that was accompanied by increased radiation sensitivity in the human HCT116 colon cancer cells. However, when delivered intratumorally to xenograft human tumors, minimal anti-tumor effects of the virus were seen either alone or in combination with radiation therapy, suggesting an inefficiency of the non-replicative adenovirus in delivering shRNA genes to the tumor mass. When a conditionally replicative adenovirus targeted to telomerase-positive tumor cells was used in conjunction with the DNA-PKcs-targeted shRNA-encoding non-replicative adenovirus, the efficiency of tumor-specific anti-DNA-PKcs shRNA gene expression was enhanced significantly. Most importantly, this enhanced shRNA expression led to significant anti-tumor efficacy of concurrently delivered radiation therapy. Our results suggest our shRNA-based DNA-PKcs- targeting approach in combination with tumor-targeting replicative adenovirus is a promising method to sensitize solid tumors to radiation therapy.
    Translational Cancer Research 06/2012; 1(2):4-14.
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    ABSTRACT: Low gene transfer rate in tumors, high dose-induced acute inflammatory response, and lack of an immunocompetent preclinical animal model to accurately reflect the therapeutic efficacy are prominent reasons for the lack of clinical success of adenoviral (Ad) vectors. In this study, we tested whether human replication-competent adenovirus (RCAd) can replicate in T739 mouse bladder transitional tumor cells (BTT) and lung adenocarcinoma cells (LA795), and whether RCAd can enhance the transduction rate and transgene expression of human replication defective adenoviruses (RDAd) in these tumor cells in vitro and in vivo. We demonstrated that human RCAd exhibited good infectability and cytopathologic effects in mouse BTT and LA795 cells, which was comparable to that in A549 and NCIH460 human tumor cells. In contrast, no infectability and cytopathologic effects were observed in other three mouse tumor cells such as 4T1, B16, and Lewis cells. The combined use of RCAd with RDAd significantly enhanced RDAd transduction efficiency in BTT and LA795 tumor cells in vitro and in vivo. When BTT and LA795 cells were co-infected with RDAd Ad-EGFP and RCAd, a large amount of E1a expression and 2-3 orders of increases in Ad-EGFP genomic DNA were observed. In contrast, the expression of the late gene Hexon is very low, which may explain ineffective packaging of viral particles. In conclusion, our study provided a novel immunocompetent animal model which is useful for evaluating RCAd infectability, cytopathy, and replication. The combined use of RCAd and RDAd provided a new solution for cancer gene therapy.
    Tumor Biology 05/2012; 33(4):1245-53. · 2.52 Impact Factor
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    ABSTRACT: Recombinant adeno-associated viral vector serotype 2 (rAAV2) has been used with success to deliver retina-targeted gene therapeutics in retinal degeneration. However, one of the major limitations of this approach is the vector's low transduction efficiency. This study is designed to increase AAV2 transduction efficiency in vitro and in vivo. Green fluorescence protein (GFP) or luciferase reporter gene-carried rAAV2 vectors were applied to cultured human RPE cells (ARPE-19) or animal eyes with or without chemotherapeutic agents. GFP transduction efficiency was evaluated by image, flow cytometry analysis, and Western blot. The ciliary neurotrophic factor (rAAV2-CNTF)-carried AAV2 vector was coinjected to subretinal space with or without chemotherapeutic agent. The therapeutic efficacy was evaluated by counting numbers of remaining photoreceptors in retina sections of treated or untreated eyes. Coadministration of 0.1 μg/mL doxorubicin (DXR), 0.14 μg/mL cytarabine (Ara-C), 1 μg/mL etoposide (VP-16), or 20 μg/mL cisplatin (DDP) significantly increased rAAV2-mediated GFP and/or luciferase expression in cultured hRPE cells without any detectable toxicity. Pretreatment with DXR for 24 h prior to infection was most effective in enhancing rAAV2 transgene expression in hRPE cells. In addition, subretinal coinjection of rAAV2-CMV-ciliary neurotrophic factor (rAAV2-CNTF) and DXR into the eyes of rats with inherited retinal degeneration resulted in an approximately 2-fold increase in photoreceptor layer thickness and cellular density of the outer nuclear layer (ONL) compared to rAAV2-CNTF alone, reflecting a pronounced protection effect mediated by the enhanced expression of CNTF. The method described here to improve rAAV2-based gene delivery is simple and feasible without any detectable toxicity. This strategy might be therapeutically exploited in the gene therapy of degenerative retinal diseases.
    Investigative ophthalmology & visual science 03/2012; 53(6):2675-84. · 3.43 Impact Factor
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    ABSTRACT: Molecular imaging is a rapidly advancing field that allows cancer biologists to look deeper into the complex inner workings of tumor cells, or whole tumors, in a non-invasive manner. In this review, we will summarize some recent advances that enable investigators to study various important biological processes in tumors in vivo. We will discuss novel imaging approaches that allow investigators to visualize and quantify molecular pathways, such as receptor tyrosine kinase activation, hypoxia signal transduction, apoptosis, and DNA double-strand breaks. Select examples of these applications will be discussed. Because of the limited scope of this review, we will only focus on natural reporters, such as bioluminescence and fluorescent proteins.
    Radiation Research 02/2012; 177(4):508-13. · 2.70 Impact Factor
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    ABSTRACT: Transplantation of exogenous dopaminergic neuron (DA neurons) is a promising approach for treating Parkinson's disease (PD). However, a major stumbling block has been the lack of a reliable source of donor DA neurons. Here we show that a combination of five transcriptional factors Mash1, Ngn2, Sox2, Nurr1, and Pitx3 can directly and effectively reprogram human fibroblasts into DA neuron-like cells. The reprogrammed cells stained positive for various markers for DA neurons. They also showed characteristic DA uptake and production properties. Moreover, they exhibited DA neuron-specific electrophysiological profiles. Finally, they provided symptomatic relief in a rat PD model. Therefore, our directly reprogrammed DA neuron-like cells are a promising source of cell-replacement therapy for PD.
    Cell Research 11/2011; 22(2):321-32. · 10.53 Impact Factor
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    ABSTRACT: In cancer treatment, apoptosis is a well-recognized cell death mechanism through which cytotoxic agents kill tumor cells. Here we report that dying tumor cells use the apoptotic process to generate potent growth-stimulating signals to stimulate the repopulation of tumors undergoing radiotherapy. Furthermore, activated caspase 3, a key executioner in apoptosis, is involved in the growth stimulation. One downstream effector that caspase 3 regulates is prostaglandin E(2) (PGE(2)), which can potently stimulate growth of surviving tumor cells. Deficiency of caspase 3 either in tumor cells or in tumor stroma caused substantial tumor sensitivity to radiotherapy in xenograft or mouse tumors. In human subjects with cancer, higher amounts of activated caspase 3 in tumor tissues are correlated with markedly increased rate of recurrence and death. We propose the existence of a cell death-induced tumor repopulation pathway in which caspase 3 has a major role.
    Nature medicine 07/2011; 17(7):860-6. · 27.14 Impact Factor
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    ABSTRACT: DNA double-strand breaks (DSB) are a major form of DNA damage and a key mechanism through which radiotherapy and some chemotherapeutic agents kill cancer cells. Despite its importance, measuring DNA DSBs is still a tedious task that is normally carried out by gel electrophoresis or immunofluorescence staining. Here, we report a novel approach to image and quantify DSBs in live mammalian cells through bifragment luciferase reconstitution. N- and C-terminal fragments of firefly luciferase genes were fused with H2AX and MDC1 genes, respectively. Our strategy was based on the established fact that at the sites of DSBs, H2AX protein is phosphoryated and physically associates with the MDC1 protein, thus bringing together N- and C-luciferase fragments and reconstituting luciferase activity. Our strategy allowed serial, noninvasive quantification of DSBs in cells irradiated with X-rays and (56)Fe ions. Furthermore, it allowed for the evaluation of DSBs noninvasively in vivo in irradiated tumors over 2 weeks. Surprisingly, we detected a second wave of DSB induction in irradiated tumor cells days after radiation exposure in addition to the initial rapid induction of DSBs. We conclude that our new split-luciferase-based method for imaging γ-H2AX-MDC1 interaction is a powerful new tool to study DSB repair kinetics in vivo with considerable advantage for experiments requiring observations over an extended period of time.
    Cancer Research 06/2011; 71(12):4130-7. · 9.28 Impact Factor

Publication Stats

791 Citations
220.42 Total Impact Points

Institutions

  • 2014
    • Renji Hospital
      Shanghai, Shanghai Shi, China
  • 2003–2014
    • Shanghai Jiao Tong University
      • • Shanghai Key Laboratories of Pancreatic Disease
      • • School of Medicine
      • • Shanghai First People's Hospital
      Shanghai, Shanghai Shi, China
  • 2006–2013
    • Shanghai University
      • Department of Surgery
      Shanghai, Shanghai Shi, China
  • 2004–2013
    • First People's Hospital Chenzhou
      Chenchow, Hunan, China
  • 2003–2013
    • Duke University Medical Center
      • • Department of Dermatology
      • • Department of Radiation Oncology
      Durham, NC, United States
  • 2012
    • Sichuan University
      Hua-yang, Sichuan, China
  • 2002–2011
    • Shanghai Putuo District People's Hospital
      Shanghai, Shanghai Shi, China
  • 2004–2010
    • Hangzhou First People's Hospital
      Hang-hsien, Zhejiang Sheng, China
  • 2008–2009
    • Fudan University
      Shanghai, Shanghai Shi, China