Reversal of multidrug resistance in renal cell carcinoma by short hairpin RNA targeting MDR1 gene

Background  Over-expression of P-glycoprotein (P-gp), encoded by the MDR1 gene, confers multidrug resistance (MDR) in renal cell carcinoma (RCC) and is a major reason for unsuccessful chemotherapy. This study aimed to determine the effct of RNA interference (RNAi) on the reversal of MDR in human RCC.

Methods  We designed and selected one short hairpin RNA (shRNA) targeting MDR1 gene, which is stably expressed from integrated plasmid and transfected by lentivirus fluid in human RCC A498 cell.

Results  The MDR1-targeted RNAi resulted in decreased MDR1 gene mRNA level (P <0.001), almost abolished P-gp expression and reversed MDR to different chemotherapy drugs in the RCC A498 cell line.

Conclusion  MDR could be reversed by RNAi in human RCC A498 cell line, which may be used for clinical application in future.

     

Tissue-engineered calcium phosphate cement in rabbit femoral condylar bone defects

Background  Calcium phosphate cement (CPC) is a favorable bone-graft substitute, with excellent biocompatibility and osteoconductivity. However, its reduced osteoinductive ability may limit the utility of CPC. To increase its osteoinductive potential, this study aimed to prepare tissue-engineered CPC and evaluate its use in the repair of bone defects. The fate of transplanted seed cells in vivo was observed at the same time.

Methods  Tissue-engineered CPC was prepared by seeding CPC with encapsulated bone mesenchymal stem cells (BMSCs) expressing recombinant human bone morphogenetic protein-2 (rhBMP-2) and green fluorescent protein (GFP). Tissue-engineered CPC and pure CPC were implanted into rabbit femoral condyle bone defects respectively. Twelve weeks later, radiographs, morphological observations, histomorphometrical evaluations, and in vivo tracing were performed.

Results  The radiographs revealed better absorption and faster new bone formation for tissue-engineered CPC than pure CPC. Morphological and histomorphometrical evaluations indicated that tissue-engineered CPC separated into numerous small blocks, with active absorption and reconstruction noted, whereas the residual CPC area was larger in the group treated with pure CPC. In the tissue-engineered CPC group, in vivo tracing revealed numerous cells expressing both GFP and rhBMP-2 that were distributed in the medullar cavity and on the surface of bony trabeculae.

Conclusion  Tissue-engineered CPC can effectively repair bone defects, with allogenic seeded cells able to grow and differentiate in vivo after transplantation.

     

Proteomic analysis for detecting serum biomarkers related to smoking in humans

Background  Smoking is the leading cause of death in the world. This study focused on the difference of the serum proteomic profiling between healthy smokers and nonsmokers in order to find smoking-specific serum biomarkers.

Methods  Pattern-based proteomic profiling of 100 serum samples (from 50 Chinese male smokers and 50 matched nonsmokers) was performed through magnetic bead fractionation coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF-MS) and resulting data were statistically analyzed by Ciphergen ProteinChip software 3.0.2.

Results  We found 72 serum peaks were significantly different between smokers and nonsmokers (P <0.05). Marker peaks of mass-to-charge ratio (m/z) 3159.13, 7561.03 and 9407.32 were smoking-specific.

Conclusion  The preliminary data suggested that smoking-specific serum biomarkers could be detected in humans.

     

Effect of peritumoral injection of boanmycin hydrochloride within temperature-sensitive in situ gel using Hep-G2 hepatoma nude mice model

Background  Boanmycin hydrochloride, a new antitumor agent, has a short half-life and fast clearance speed in vivo. The aim of this research was to investigate the effectiveness of peritumor injection of boanmycin hydrochloride within temperature-sensitive gel in situ using Hep-G2 hepatoma nude mice model.

Methods  Nude mice with human Hep-G2 tumor in right flank were randomly divided into four groups: normal saline group, in situ gel only group, boanmycin hydrochloride in situ saline group, and boanmycin hydrochloride in situ gel group, and were treated with injection of corresponding agents into peripheral tissue of the tumor. The volume of the tumor and the body weight of the mice were regularly measured, and tumor growth curve was generated. The size, internal echo, and blood flow of the tumors were observed by color Doppler ultrasonography. Histopathologic changes of the tumor after treatment were observed under both optical and transmission electron microscopy.

Results  The tumor growth was significantly inhibited by peritumoral therapy in boanmycin hydrochloride in situ gel group with the tumor inhibitory rate of 86.76%. The blood flow of the tumor was still seen in both normal saline group and in situ gel only group on color Doppler ultrasound. Punctate calcification and dotted blood flow were seen in boanmycin hydrochloride group; however, there was massive calcification and no blood flow in the tumor in the boanmycin hydrochloride in situ gel group. Large areas of necrosis and apoptotic cells were shown by microscopic observation in boanmycin hydrochloride in situ gel group.

Conclusion  Temperature-sensitive boanmycin hydrochloride in situ gel can effectively delay the release of boanmycin hydrochloride and increase its anticancer effects for liver cancer in animal model.

     

Immature CD4+ dendritic cells conditioned with donor kidney antigen prolong renal allograft survival in rats

Background  Allogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell (DC) is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4⁺ DCs on renal allografts in the rat model.

Methods  In this study, we induced CD4⁺ immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4⁺ DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo.

Results  Immature CD4⁺ DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo.

Conclusions  Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4⁺ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.

     

Silencing of osteopontin promotes the radiosensitivity of breast cancer cells by reducing the expression of hypoxia inducible factor 1 and vascular endothelial growth factor

Background  Osteopontin (OPN) is a secreted phosphoglycoprotein (SSP) that is overexpressed in a variety of tumors and was regarded as a molecular marker of tumors. In this study, we intended to demonstrate the role of OPN in human breast cancer cell line MDA-MB-231.

Methods  Recombinant plasmid expressing small interfering RNA (siRNA) specific to OPN mRNA was transfected into MDA-MB-231 cells to generate the stable transfected cell line MDA-MB-343, and the empty plasmid tansfected cells (MDA-MB-neg) or wildtype MDA-MB-231 cells were used as control cells respectively. Expression of OPN, hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) proteins was analyzed by Western blotting analysis. The radiosensitivity of cells was determined by detecting cell apoptosis, cell proliferation and cell senescence.

Results  HIF-1 and VEGF proteins in MDA-MB-343 cells were significantly downregulated upon the efficient knockdown of OPN expression under either hypoxia or normoxia environment. Moreover, expression of OPN protein was upregualted upon hypoxic culture. Stable OPN-silencing also decreased cell invasion, increased cell apoptosis and cell senescence, as well as reduced clonogenic survival, resulting in increase radiation tolerance.

Conclusions  Suppression of OPN gene expression can enhance radiosensitivity and affect cell apoptosis in breast cancer cells. OPN seems to be an attractive target for the improvement of radiotherapy.

     

Compound mutations (R237X and L375P) in the fumarylacetoacetate hydrolase gene causing tyrosinemia type I in a Chinese patient

Background  Mutations in fumarylacetoacetate hydrolase (FAH) gene can lead to tyrosinemia type 1 (HT1), a relatively rare autosomal recessive disorder. To date, no molecular genetic defects of HT1 in China have been described. We investigated a Chinese family with a HT1 child to identify mutations in FAH.

Methods  DNA sequencing was used for mutations screening in FAH gene. Real-time polymerase chain reaction (PCR) was performed to determine the FAH gene expression level. To confirm the presence of degradation by the nonsense-mediated mRNA decay pathway (NMD), the fragments containing R237X mutations were analyzed by primer introduced restriction analysis-polymerase chain reaction (PIRA-PCR) and cDNA sequencing. Finally, the effects of the mutations reported in this study were predicted by online softwares.

Results  A boy aged 3 years and 8 months was diagnosed clinically with HT1 based on his manifestations and biochemical abnormalities. Screening of FAH gene revealed two heterozygous mutations R237X and L375P transmitted from his mother and father respectively. In this pedigree, the amount of FAH mRNA relative to a healthy control was 0.44 for the patient, 0.77 for his mother and 1.07 for his father. Moreover, both PIRA-PCR and cDNA sequencing showed significant reduction of the FAH mRNA with R237X nonsense mutation. The missense mutation of L375P was not reported previously and prediction software showed that this mutation decreased the stability of protein structure and affected protein function.

Conclusions  This is the first case of HT1 analyzed by molecular genetics in China. The R237X mutation in FAH down- regulates the FAH gene expression, and the L375P mutation perhaps interrupts the secondary structure of FAH protein.

     

Increased expression of serum gelsolin in patients with osteosarcoma.

Background  Identification of potential serum biomarkers of osteosarcoma to aid in its early diagnosis and in the discovery of possible therapeutic targets is an area of increasing interest.

Methods  Two-dimensional difference-in-gel electrophoresis was used to assess multiple serum samples in patients with osteosarcoma. In addition, differential expression of protein biomarkers was characterized in osteosarcoma serum by using matrix-assisted desorption/ionization time-of-flight mass spectrometry coupled with database interrogation. Serum samples from four individuals with osteosarcoma and four age- and sex-matched healthy control subjects were compared.

Results  Fifty-eight significant protein spot features in the osteosarcoma sera were found. These spot features were excised, digested with trypsin, and analyzed with mass spectrometry. Gelsolin was down-regulated only in osteosarcoma. Furthermore, Western blotting and enzyme linked immunosorbent assay (ELISA) confirmed decreased levels of gelsolin in the osteosarcoma serum samples.

Conclusions  These results indicated that gelsolin might have great potential as a biomarker of osteosarcoma and as a potential target for gene therapy.

     

Gene delivery in peritoneal dialysis related peritoneal fibrosis research

Objective  To summarize the development of gene delivery vectors in peritoneal fibrosis research and discuss the feasibility and superiority of lentiviral vectors.

Data sources  The data in this article were collected from PubMed database with relevant English articles published from 1995 to 2011.

Study selection  Articles regarding the gene therapy in peritoneal fibrosis research using non-viral vectors, adenoviral vectors, retroviral vectors, and lentiviral vectors were selected. Data were mainly extracted from 60 articles, which are listed in the reference section of this review.

Results  Non-viral vector-mediated gene delivery (including naked DNA for ex vivo, oligonucleotides, ultrasound- contrast agent mediated naked gene delivery, etc.) and viral vector-mediated gene delivery (including adenovirus, helper-dependant adenovirus, and retrovirus vectors) have been successfully applied both in the mechanistic investigation and the potential prevention and treatment of peritoneal fibrosis.

Conclusions  Peritoneal fibrosis is a major complication of peritoneal dialysis (PD). Recently, the wide use of the gene delivery technique made it possible to access and further research peritoneal fibrosis. The use of lentiviral vector is expected to be widely used in PD research in the future due to its advantages in gene delivery.

     

Role of microRNA-181a in the apoptosis of tubular epithelial cell induced by cisplatin 

Background  Cisplatin (DDP) is one of most effective and most commonly used therapeutic agent in treating tumors, it can accumulate in the kidney and lead to acute renal failure. MicroRNA-181a can induce cell apoptosis by suppressing the expression of Bcl-2 family. In the present study, we investigated the role of microRNA-181a in the apoptosis of tubular epithelial cell induced by DDP.

Methods  HK-2 cells were cultured, transfected with microRNA-181a inhibitor for 48 hours, and stimulated with 50 µmol/L cisplatin for 24 hours. MicroRNA-181a expression was analyzed by real time PCR, and cell apoptosis was detected by flow cytometry. Moreover, Bcl-2 and Bcl-2-associated X protein (Bax) expression were measured by Western blotting.

Results  MicroRNA-181a expression significantly down-regulated in cells transfected with microRNA-181a inhibitor, compared with that in untransfectd cells (21.19±2.01 vs. 38.87±1.97, P <0.05). Cell apoptosis induced by DDP significantly decreased in cells transfected with MicroRNA-181a inhibitor. Compared with DDP treated cells alone, Bcl-2 expression strikingly was up-regulated and Bax expression was down-regulated in cells transfected with microRNA-181a inhibitor.

Conclusion  One pathway of DDP induces apoptosis of tubular epithelial cell by suppressing Bcl-2 expression is achieved by regulating the target gene of MicroRNA-181a.

     

Gliosis after traumatic brain injury in conditional ephrinB2-knockout mice

Background  In response to the injury of the central nervous system (CNS), the astrocytes upregulate the expression of glial fibrillary acidic protein (GFAP), which largely contributes to the reactive gliosis after brain injury. The regulatory mechanism of this process is still not clear. In this study, we aimed to compare the ephrin-B2 deficient mice with the wild type ones with regard to gliosis after traumatic brain injury.

Methods  We generated ephrin-B2 knockout mice specifically in CNS astrocytes. Twelve mice from this gene-knockout strain were randomly selected along with twelve mice from the wild type littermates. In both groups, a modified controlled cortical impact injury model was applied to create a closed traumatic brain injury. Twenty-eight days after the injury, Nissl staining and GFAP immunofluorescence staining were used to compare the brain atrophy and GFAP immunoreactivity between the two groups. All the data were analyzed by t-test for between-group comparison.

Results  We successfully set up the conditional ephrin-B2 knockout mice strain, which was confirmed by genotyping and ephrin-B2/GFAP double staining. These mice developed normally without apparent abnormality in general appearance. Twenty-eight days following brain injury, histopathology revealed by immunohistochemistry showed different degrees of cerebral injuries in both groups. Compared with wild-type group, the ephrin-B2 knockout group exhibited less brain atrophy ratio for the injured hemispheres (P=0.005) and hippocampus (P=0.027). Also the wild-type group demonstrated greater GFAP immunoreactivity increment within hippocampal regions (P=0.008).

Conclusions  The establishment of conditional ephrin-B2 knockout mice provides us with a new way to explore the role of ephrin-B2 in astrocytes. Our findings revealed less atrophy and GFAP immunoreactivity in the knockout mice strain after traumatic brain injury, which implied ephrin-B2 could be one of the promoters to upregulate gliosis following brain injury.

     

Enhanced expression of proneurotrophins in elevated introcular pressure-induced rat retinal ischemia

Background  Proneurotrophins such as the precursor of nerve growth factor (proNGF) and the precursor of brain-derived neurotrophic factor (proBDNF) interacted with sortilin and p75^NTR to form a complex capable of activating an apoptotic signaling. We found that the expression of p75^NTR and sortilin was increased in ischemic retina induced by elevated intraocular pressure (IOP), but the protein expression changes of proNGF and proBDNF in the same situation were not clear. This study aimed to ascertain the protein expression changes of proNGF and proBDNF in ischemic retina induced by elevated IOP.

Methods  Expression of proBDNF and proNGF was examined by double-labeling immunochemistry in normal rat retina, examined using Western blotting and analyzed using statistical methods in ischemic retina induced by elevated IOP.

Results  Immunocytochemistry showed that the proBDNF expressed in the ganglion cell layer (GCL) while the proNGF primarily existsed in both the nerve fiber layers (NFL) and large ganglion cell bodies of normal rat retina. Western blotting analysis demonstrated that the molecule weights of 28 kD (proBDNF) / 25 kD (proNGF) band were increased significantly (P <0.05) at days 3, 5 and 7 after retinal elevated-IOP-induced ischemia.

Conclusion  ProBDNF expressed in the GCL and proNGF primarily presented in NFL and large ganglion cell bodies of normal rat retina, the protein expression forms of 28 kD proBDNF and 25 kD proNGF increased in ischemic retina induced by elevated IOP.

     

创伤骨科患者创伤严重程度和血浆D二聚体水平的相关分析

Background  The correlation between the plasma D-dimer level and deep vein thrombosis has not been conclusive in various studies. The aim of this research was to study the relationship between plasma D-dimer levels and the severity of orthopedic trauma by retrospective examination of orthopedic trauma cases.

Methods  Clinically acute trauma and non-acute trauma patients were selected and their plasma D-dimer levels were measured. Plasma D-dimer levels in patients of these two groups were compared. The relationship between the plasma D-dimer level and the severity of the trauma was also studied.

Results  There were 548 cases in the acute trauma group and 501 cases in the non-acute trauma group. The levels of plasma D-dimer were significantly higher in the acute trauma group than in the non-acute trauma group (P <0.01). In the acute trauma group, the correlation between the D-dimer level and the number of fractures was a positive linear correlation (r=0.9532).

Conclusions  Elevated plasma D-dimer is common in trauma patients. The D-dimer level and the number of fractures in the trauma patients are closely correlated. D-dimer is not only an indicator for the diagnosis of deep vein thrombosis and pulmonary embolus, but also an indicator of the severity of trauma in acute trauma patients.

     

Epicardial radiofrequency ablation for left ventricular aneurysm related ventricular arrhythmias during off-pump coronary artery bypass surgery

Background  Left ventricular aneurysm (LVA) is one of the serious complications after acute myocardial infarction. We attempted to evaluate the preliminary efficacy of LVA repair combined with epicardial radiofrequency ablation for ventricular arrhythmia during off-pump coronary artery bypass grafting (OPCAB).

Methods  From June 2009 to April 2011, 31 patients with LVA had angina symptoms and ventricular arrhythmia. In all patients, circular and cross-shaped radiofrequency epicardial ablations were performed using unipolar ablation pen along the border between the aneurysm wall and normal cardiac tissue and in the central zone of the aneurysms, followed by a linear placation of ventricular aneurysms on beating heart.

Results  All the patients showed complete recovery. The average number of grafted vessels was 2.7±1.3. Intraoperative examinations revealed that the ventricular arrhythmia was effectively controlled by radiofrequency ablation. All cases had been followed up for one year. Holter monitoring revealed a significant reduction in ventricular arrhythmias (P <0.05). Echocardiography showed significant increase in left ventricular ejection fraction (P <0.05) and decrease in left ventricular end-diastolic diameter (P <0.05).

Conclusions  For patients with ventricular aneurysm and preoperative malignant arrhythmia, aneurysm repair plus epicardial radiofrequency ablation in OPCAB was found to be an effective and feasible therapeutic technique. However, medium- to long-term therapeutic efficacy of this method remains to be determined by future studies and observations.

     

Clinical features and imaging findings in pulmonary capillary hemangiomatosis: report of two cases and a pooled analysis

Background  Pulmonary capillary hemangiomatosis (PCH) is a rare disease and no Chinese case has been reported yet. The disease is often misdiagnosed and its clinical characteristics are incompletely described. The aim of this study was to describe two Chinese cases and to clarify the clinical and radiographic parameters of patients with PCH.

Methods  Two PCH cases were presented and other cases were searched from the English literature. All available clinical and radiographic data were collected from 62 literature reported PCH cases. A pooled analysis of total 64 cases was made.

Results  Dyspnea and hemoptysis were the most common clinical symptoms of PCH. Pulmonary hypertension (PH) was found in 78% of the reported cases. PCH typically showed characteristic diffuse or patchy ground-glass opacities (GGOs) and/or multiple ill-defined centrilobular nodules in the computed tomography.

Conclusions  The diagnosis of PCH requires a high clinical suspicion. However, both clinical presentations and radiographic studies often provide clues to the diagnosis, which may prompt early lung biopsy for a definite diagnosis.

     

Transitional cell carcinoma associated with aristolochic acid nephropathy: most common cancer in chronic hemodialysis patients in China

Background  The research of cancer in patients on hemodialysis (HD) in China has not been reported. The aim of this study was to investigate the clinical and histological features and outcomes of cancer in Chinese HD patients.

Methods  The study subjects were 49 cancer patients (1.4%) out of 3448 end stage renal disease (ESRD) patients maintained on HD at China-Japan Friendship Hospital from October 1997 to July 2011.

Results  Urinary tract cancer (74%) was the most common followed by gastrointestinal tract cancer (12%), breast cancer (6%), lung cancer (4%), thyroid cancer (2%), and hematologic cancer (2%). Thirty-three patients (67%) had urinary tract transitional cell carcinoma (TCC) and 29 of them had aristolochic acid nephropathy (AAN) as underlying disease. Death occurred in eight patients out of 49, and the survival rate of HD patients with cancer was similar to those without cancer (P=0.120).

Conclusion  The urinary tract TCC is the most common cancer in HD patients with AAN in one of the centers of northern China.