Zhong H.,Peking University |
Wang D.,Peking University |
Wang N.,Peking University |
Rios Y.,University of California at Los Angeles |
And 5 more authors.
Cell Research | Year: 2011
Blood vessels normally maintain stereotyped lumen diameters and their stable structures are crucial for vascular function. However, very little is known about the molecular mechanisms controlling the maintenance of vessel diameters and the integrity of endothelial cells. We investigated this issue in zebrafish embryos by a chemical genetics approach. Small molecule libraries were screened using live Tg(kdrl:GRCFP)zn1 transgenic embryos in which endothelial cells are specifically labeled with GFP. By analyzing the effects of compounds on the morphology and function of embryonic blood vessels after lumen formation, PP1, a putative Src kinase inhibitor, was identified as capable of specifically reducing vascular lumen size by interrupting endothelial-cell integrity. The inhibitory effect is not due to Src or general VEGF signaling inhibition because another Src inhibitor and Src morpholino as well as several VEGFR inhibitors failed to produce a similar phenotype. After profiling a panel of 22 representative mammalian kinases and surveying published data, we selected a few possible new candidates. Combinational analysis of these candidate kinase inhibitors established that PP1 induced endothelial collapse by inhibiting both the VEGFR2 and MAP kinase pathways. More importantly, combinatory use of two clinically approved drugs Dasatinib and Sunitinib produced the same phenotype. This is the first study to elucidate the pathways controlling maintenance of endothelial integrity using a chemical genetics approach, indicating that endothelial integrity is controlled by the combined action of the VEGFR2 and MAP kinase pathways. Our results also suggest the possible side effect of the combination of two anticancer drugs on the circulatory system. © 2011 IBCB, SIBS, CAS All rights reserved.
Duan Z.,Massachusetts General Hospital |
Zhang J.,Massachusetts General Hospital |
Ye S.,Massachusetts General Hospital |
Shen J.,Massachusetts General Hospital |
And 8 more authors.
BMC Cancer | Year: 2014
Background: Reversing multidrug resistance (MDR) has been an important goal for clinical and investigational oncologists. In the last few decades, significant effort has been made to search for inhibitors to reverse MDR by targeting ATP-binding cassette (ABC) transporters (Pgp, MRP) directly, but these efforts have achieved little clinical success. Protein kinases play important roles in many aspects of tumor cell growth and survival. Combinations of kinase inhibitors and chemotherapeutics have been observed to overcome cancer drug resistance in certain circumstances.Methods: We screened a kinase specific inhibitor compound library in human osteosarcoma MDR cell lines to identify inhibitors that were capable of reversing chemoresistance to doxorubicin and paclitaxel.Results: We identified 18 small molecules that significantly increase chemotherapy drug-induced cell death in human osteosarcoma MDR cell lines U-2OSMR and KHOSR2. We identified A-770041 as one of the most effective MDR reversing agents when combined with doxorubicin or paclitaxel. A-770041 is a potent Src family kinase (Lck and Src) inhibitor. Western blot analysis revealed A-770041 inhibits both Src and Lck activation and expression. Inhibition of Src expression in U-2OSMR and KHOSR2 cell lines using lentiviral shRNA also resulted in increased doxorubicin and paclitaxel drug sensitivity. A-770041 increases the intracellular drug accumulation as demonstrated by calcein AM assay.Conclusions: These results indicate that small molecule inhibitor A-770041 may function to reverse ABCB1/Pgp-mediated chemotherapy drug resistance. Combination of Src family kinase inhibitor with regular chemotherapy drug could be clinically effective in MDR osteosarcoma. © 2014 Duan et al.; licensee BioMed Central Ltd.
Yang T.,Southern Medical University |
Zheng X.-F.,Liu Hua Qiao Hospital |
Lin X.,Southern Medical University |
Yin Q.-S.,Liu Hua Qiao Hospital
Medical Hypotheses | Year: 2013
Giant cell tumor of bone (GCTB) is a common benign bone tumor characterized by local osteolysis and high proclivity for recurrence. Surgical excision is the preferred treatment. However, simple wide resection may cause functional and cosmetic deformities of the skeleton. Currently, intralesional curettage with adjuvant therapy is a popular treatment. Bisphosphonates are recommended as an effective adjuvant treatment, and their antitumor effects have been proved in laboratory studies. During clinical treatment, intravenous and peroral administration of bisphosphonates has been attempted and has been successful in reducing the tumor recurrence rate. However, the use of bisphosphonates in GCTB adjuvant therapy requires additional study. Irrigation is a classic method for focal clearance after surgery. Therefore, we hypothesize that postoperative irrigation with bisphosphonates may be a safe and effective treatment for GCTB. The efficacy and safety of this method are worthy of further investigation. © 2013 Elsevier Ltd.
Zhao H.,Liu Hua Qiao Hospital |
Li M.,Liu Hua Qiao Hospital |
Li L.,Liu Hua Qiao Hospital |
Yang X.,Liu Hua Qiao Hospital |
And 2 more authors.
PLoS ONE | Year: 2013
MicroRNAs (miRNAs) decrease the expression of specific target oncogenes or tumor suppressor genes and thereby play crucial roles in tumorigenesis and tumor growth. To date, the potential miRNAs regulating osteosarcoma growth and progression are not fully identified yet. In this study, the miRNA microarray assay and hierarchical clustering analysis were performed in human osteosarcoma samples. In comparison with normal human skeletal muscle, 43 miRNAs were significantly differentially expressed in human osteosarcomas (fold change ≥2 and p≤0.05). Among these miRNAs, miR- 133a and miR-133b expression was decreased by 135 folds and 47 folds respectively and the decreased expression was confirmed in both frozen and paraffin-embedded osteosarcoma samples. The miR-133b precursor expression vector was then transfected into osteosarcoma cell lines U2-OS and MG-63, and the stable transfectants were selected by puromycin. We found that stable over-expression of miR-133b in osteosarcoma cell lines U2-OS and MG-63 inhibited cell proliferation, invasion and migration, and induced apoptosis. Further, over-expression of miR-133b decreased the expression of predicted target genes BCL2L2, MCL-1, IGF1R and MET, as well as the expression of phospho-Akt and FAK. This study provides a new insight into miRNAs dysregulation in osteosarcoma, and indicates that miR-133b may play as a tumor suppressor gene in osteosarcoma. © 2013 Zhao et al.
Duan Z.,Massachusetts General Hospital |
Shen J.,Massachusetts General Hospital |
Yang X.,Massachusetts General Hospital |
Yang P.,Massachusetts General Hospital |
And 9 more authors.
Journal of Orthopaedic Research | Year: 2014
Reliable prognostic biomarkers for chordoma have not yet been established. Recent studies revealed that expression of miRNA-1 (miR-1) is frequently downregulated in several cancer types including chordoma. The goal of this follow-up study is to investigate the expression of miR-1 as a prognostic biomarker and further confirm the functional role of miR-1 in chordoma cell growth and proliferation. We determined the relative expression levels of miR-1 and Met in chordoma tissue samples and correlated those to clinical variables. The results showed that miR-1 was downregulated in 93.7% of chordoma tissues and expression was inversely correlated with Met expression. miR-1 expression levels also correlated with clinical prognosis. To characterize and confirm the functional role of miR-1 in the growth and proliferation of chordoma cells, miR-1 precursors were stably transfected into chordoma cell lines UCH-1 and CH-22. Cell Proliferation Assay and MTT were used to evaluate cell growth and proliferation. Restoring expression of miR-1 precursor decreased cell growth and proliferation in UCH-1 and CH-22 cells. These results indicate that suppressed miR-1 expression in chordoma may in part be a driver for tumor growth, and that miR-1 has potential to serve as prognostic biomarker and therapeutic target for chordoma patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
Xiangdong Q.I.,Liu Hua Qiao Hospital |
Limin M.A.,Liu Hua Qiao Hospital |
Shizhen Z.,Southern Medical University
Journal of Cranio-Maxillofacial Surgery | Year: 2012
Objective: To investigate the influence of the closing and opening muscle groups of the jaw on mandibular stability after mandibular bilateral sagittal split ramus osteotomy (BSSRO). Materials and methods: To establish finite element models of four conditions (the normal mandible, preoperative mandibular prognathism, postoperative (BSSRO) mandibular prognathism, and mandibular prognathism following virtual BSSRO), we imported Digital Imaging and Communications in Medicine (DICOM) data into three-dimensional reconstruction software. Finite element analysis software and statistical software were used for analysis of the condylar stress distribution as a function of condylar position during the actions of jaw closing and jaw opening muscle groups. Results: The stress distribution of the normal mandibular bilateral condyle was statistically different from the normal mandibular condyle, indicating that bilateral structures are asymmetrical. There was a significant difference in stress distributions with condyle position between healthy control patients and patients prior to mandibular prognathism surgery (P < 0.05). There was no significant difference in stress distributions between the normal mandible and the mandible following virtual surgery or real mandibular prognathism surgery. Additionally, there was no significant difference at 6 months after mandibular prognathism surgery (P > 0.05). Conclusions: Bilateral structures of the normal mandible were asymmetrical. After mandibular bilateral sagittal split ramus osteotomy, variation of the force arms of closing and opening muscle groups of the jaw was one of the major factors influencing mandibular stability. Virtual surgery is a promising strategy for preoperative planning to improve surgical success and reduce complications. © 2011 European Association for Cranio-Maxillo-Facial Surgery.
Yang J.C.,Liu Hua Qiao Hospital |
Ma X.Y.,Liu Hua Qiao Hospital |
Lin J.,Southern Medical University |
Wu Z.H.,Liu Hua Qiao Hospital |
And 2 more authors.
International Orthopaedics | Year: 2011
The correction of severe thoracic deformities is challenging. However, the usual imaging modalities are not sufficient for performing the surgery. Our objective was to describe the procedure and results of posterior modified wedge osteotomy aided by the techniques of computer-aided design-rapid prototyping (CAD-RP) to correct thoracic deformities. Twenty-one patients with thoracic deformities (eight males; 13 females) formed the study group. All patients underwent computed tomography (CT) scanning and CAD-RP, and a model of thoracic deformities and navigation templates of pedicles were created for each patient and used to analyse the spinal deformities and serve as anatomical reference. Aided by these models, personalised modified wedge osteotomy combining the eggshell technique and posterior vertebral column resection was performed. Using CAD-RP improved the safety and accuracy of surgery and screw placement in the 21 patients in whom 41 vertebrae were removed and 216 pedicle screws were placed. The average operation time was 260 (200-420) min, with an average blood loss of 1,900 ml (range 800-3560 ml). The percentage of deformity correction was 56.3% (from 72.1° to 31.5°) in the coronal plane and 60.4% (from 81.6°to 32.3°) in the sagittal plane. No patient had serious complications or implant failure. Personalised single-stage posterior modified wedge osteotomy is an effective procedure for treating thoracic deformities. Using CAD-RP and the RP models have significant benefits for personalised surgical treatment of complex thoracic deformities. © 2010 Springer-Verlag.
Huang M.-J.,Southern Medical University |
Huang M.-J.,Academy of Orthopedics |
Wang L.,Southern Medical University |
Wang L.,Academy of Orthopedics |
And 22 more authors.
Annals of the Rheumatic Diseases | Year: 2014
Background: An exogenous supplement of n-3 polyunsaturated fatty acids (PUFAs) has been reported to prevent osteoarthritis (OA) through undefined mechanisms. Objective: This study investigated the effect of alterations in the composition of endogenous PUFAs on OA, and associations of PUFAs with mammalian target of rapamycin complex 1 (mTORC1) signalling, a critical autophagy pathway in fat-1 transgenic (TG) mice. Methods: fat-1 TG and wild-type mice were used to create an OA model by resecting the medial meniscus. The composition of the endogenous PUFAs in mouse tissues was analysed by gas chromatography, and the incidence of OA was evaluated by micro-computed tomography (micro-CT), scanning electron microscopy and histological methods. Additionally, primary chondrocytes were isolated and cultured. The effect of exogenous and endogenous PUFAs on mTORC1 activity and autophagy in chondrocytes was assessed. Results: The composition of endogenous PUFAs of TG mice was optimised both by increased n-3 PUFAs and decreased n-6 PUFAs, which significantly alleviated the articular cartilage destruction and osteophytosis in the OA model (p<0.01), decreased protein expression of matrix metalloproteinase-13 (MMP-13) and ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs) in the articular cartilage (p<0.01) and reduced chondrocyte number and loss of cartilage extracellular matrix. Both exogenous and endogenous n-3 PUFAs downregulated mTORC1 activity and promoted autophagy in articular chondrocytes. Conversely, mTORC1 pathway activation suppressed autophagy in articular chondrocytes. Conclusions: Enhancement of the synthesis of endogenous n-3 PUFAs from n-6 PUFAs can delay the incidence of OA, probably through inhibition of mTORC1, promotion of autophagy and cell survival in cartilage chondrocytes. Future investigation into the role of the endogenous n-6/n-3 PUFAs composition in OA prevention and treatment is warranted.
Huang H.,University of California at Los Angeles |
Lindgren A.,University of California at Los Angeles |
Wu X.,Liu Hua Qiao Hospital |
Liu N.-A.,Cedars Sinai Medical Center |
Lin S.,University of California at Los Angeles
Cell Reports | Year: 2012
Transgenic zebrafish embryos expressing tissue-specific green fluorescent protein (GFP) can provide an unlimited supply of primary embryonic cells. Agents that promote the differentiation of these cells may be beneficial for therapeutics. We report a high-throughput approach for screening small molecules that regulate cell differentiation using lineage-specific GFP transgenic zebrafish embryonic cells. After validating several known regulators of the differentiation of endothelial and other cell types, we performed a screen for proangiogenic molecules using undifferentiated primary cells from flk1-GFP transgenic zebrafish embryos. Cells were grown in 384-well plates with 12,128 individual small molecules, and GFP expression was analyzed by means of an automated imaging system, which allowed us to screen thousands of compounds weekly. As a result, 23 molecules were confirmed to enhance angiogenesis, and 11 of them were validated to promote the proliferation of mammalian human umbilical vascular endothelial cells and induce Flk1+ cells from murine embryonic stem cells. We demonstrated the general applicability of this strategy by analyzing additional cell lineages using zebrafish expressing GFP in pancreatic, cardiac, and dopaminergic cells
PubMed | Liu Hua Qiao Hospital
Type: Journal Article | Journal: PloS one | Year: 2014
MicroRNAs (miRNAs) decrease the expression of specific target oncogenes or tumor suppressor genes and thereby play crucial roles in tumorigenesis and tumor growth. To date, the potential miRNAs regulating osteosarcoma growth and progression are not fully identified yet. In this study, the miRNA microarray assay and hierarchical clustering analysis were performed in human osteosarcoma samples. In comparison with normal human skeletal muscle, 43 miRNAs were significantly differentially expressed in human osteosarcomas (fold change 2 and p0.05). Among these miRNAs, miR-133a and miR-133b expression was decreased by 135 folds and 47 folds respectively and the decreased expression was confirmed in both frozen and paraffin-embedded osteosarcoma samples. The miR-133b precursor expression vector was then transfected into osteosarcoma cell lines U2-OS and MG-63, and the stable transfectants were selected by puromycin. We found that stable over-expression of miR-133b in osteosarcoma cell lines U2-OS and MG-63 inhibited cell proliferation, invasion and migration, and induced apoptosis. Further, over-expression of miR-133b decreased the expression of predicted target genes BCL2L2, MCL-1, IGF1R and MET, as well as the expression of phospho-Akt and FAK. This study provides a new insight into miRNAs dysregulation in osteosarcoma, and indicates that miR-133b may play as a tumor suppressor gene in osteosarcoma.