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P-glycoprotein (P-gp) is a major efflux transporter overexpressed on multidrug resistant tumor cells and responsible for pumping drugs out. If anti-tumor drugs are given when P-gp level is low, satisfactory treatment efficiency may be achieved. Thus, a P-gp down-regulating siRNA (siMDR1) and doxorubicin (DOX) were applied to eliminate multidrug resistant breast cancer cells (MCF-7/ADR). A redox-responsive glucolipid conjugate (CSO-ss-SA) was used to condense siRNA (CSO-ss-SA/siRNA) and encapsulate DOX (CSO-ss-SA/DOX) separately. They responded to the high reducing environment of tumor cells and fast released the payload. CSO-ss-SA/siMDR1 silenced MDR1 gene and resulted in a transient decrease of P-gp. Sequentially, DOX formulation (CSO-ss-SA/DOX or DOX·HCl) was delivered when P-gp was reduced to the lowest level. After pretreatment by CSO-ss-SA/siMDR1, cytotoxicity of CSO-ss-SA/DOX and DOX·HCl against MCF-7/ADR cells were 6.4 or 3.4-fold respectively of that treated by DOX·HCl alone, which exhibited increased cytotoxin sensitivity of drug resistant cells and maximized therapeutic outcomes. These results revealed that the sequential treatment strategy of CSO-ss-SA/siRNA and CSO-ss-SA/DOX hold potential in achieving an optimal overcoming multidrug resistance efficiency., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In order to construct an Escherichia coli strain with high sensitivity and specificity to detect arsenic ion using fluorescence as reporter, a sensitive strain to arsenic ion was obtained by knocking out the gene arsB that acts as an arsenic efflux pump. The pET28b vector containing arsenite detecting cassette Pars-arsR-egfp was constructed and then transformed into arsB deleted mutant. Measuring conditions of this constructed whole-cell biosensor were optimized and its linear concentration range, limit of detection and specificity were determined. This modified biosensor was much more sensitive than that using wild-type strain as host. The optimal detection range of As³⁺ concentration was 0.013 to 42.71 μmol/L, and the limit concentration of detection was as low as 5.13 nmol/L. Thus we successfully improved the sensitivity of arsenite detecting biosensor by modification of E. coli genome, which may provide useful strategies for development and optimization of microbial sensors to detect heavy metals.

To detect cadmium ions, we constructed a specific microbial sensor and screened detecting cassettes and different fluorescence proteins. Blue fluorescence protein mTagBFP2 was selected as a reporter and a double-promoters model was used in the construction of the fusion reporter vector Pmer::merR-m-Pmer::mTagBFP2-pMD19-T. The reporter vector was then transformed into Escherichia coli MC4100 wild type strain. The medium, incubation time, initial density for induction, and the optimal detection range were determined. The specificity of the biosensor was also checked. The biosensor responded specifically to cadmium irons with low background, and the linear concentration range detection ranged from 0.1 to 75 μmol/L at the initial OD600 = 0.1 with 2 h incubation in IHMM medium. Thus we successfully constructed a specific biosensor to detect cadmium irons and provided useful strategies for development and optimization of microbial sensors to detect heavy metals.

To develop a simple and rapid method for the simultaneous determination of nicotine and its nine metabolites in rat blood, an in vivo microdialysis sampling technique coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for quantitation and characterization of the pharmacokinetics of nicotine and its metabolites. Microdialysis probes were inserted into the jugular vein of Sprague Dawley rats, and dialysates were collected after nicotine (0.5 mg/kg, i.p.) administration. Target analytes and corresponding deuterated internal standards were separated on a hydrophilic interaction liquid chromatography column (HILIC BEH 2.1. × 150 mm, 1.7 μm) and detected by UPLC-MS/MS under multiple reaction monitoring mode. The limits of quantification for nicotine and its nine metabolites ranged from 0.039 to 0.46 ng/mL. Intra- and inter-day precision and accuracy were well within the predefined limits of acceptability (<11 %). Pharmacokinetic results showed that the mean half-lives of nicotine, cotinine, nornicotine, norcotinine, nicotine-N'-oxide, cotinine-N'-oxide, trans-3'-hydroxy-cotinine, nicotine-N-glucuronide, cotinine-N-glucuronide, and trans-3'-hydroxy-cotinine-O-glucuronide in rat plasma were 63, 291, 175, 440, 251, 451, 322, 341, 488, and 516 min, respectively. The blood concentration-time profiles of nicotine and its nine metabolites indicate that nicotine is rapidly consumed after the administration and subsequently cotinine is generated as the main metabolite; meanwhile, cotinine and other eight minor metabolites exhibit longer retention times in rat body.

(-)-Gossypol, a natural BH3-mimetic and small-molecule Bcl-2 inhibitor, shows promise in ongoing phase II clinical trials for human cancers. However, whether (-)-gossypol plays functional roles in tumor angiogenesis has not been directly elucidated yet. In this study, we showed that (-)-gossypol dose dependently inhibited the expression of VEGF, Bcl-2, and Bcl-xL in human prostate cancer cells (PC-3 and DU 145) and primary cultured human umbilical vascular endothelial cells (HUVEC) in vitro. Notably, the growth of human prostate tumor PC-3 xenografts in mice was significantly suppressed by (-)-gossypol at a dosage of 15 mg/kg/d. This inhibitory action of (-)-gossypol in vivo was largely dependent on suppression of angiogenesis in the solid tumors, where VEGF expression and microvessel density were remarkably decreased. Furthermore, (-)-gossypol inhibited VEGF-induced chemotactic motility and tubulogenesis in HUVECs and human microvascular endothelial cells and suppressed microvessel sprouting from rat aortic rings ex vivo. When examined for the mechanism, we found that (-)-gossypol blocked the activation of VEGF receptor 2 kinase with the half maximal inhibitory concentration of 2.38 μmol/L in endothelial cells. Consequently, the phosphorylation of key intracellular proangiogenic kinases induced by VEGF was all suppressed by the treatment, such as Src family kinase, focal adhesion kinase, extracellular signal-related kinase, and AKT kinase. Taken together, the present study shows that (-)-gossypol potently inhibits human prostate tumor growth through modulating VEGF signaling pathway, which further validates its great potential in clinical practice.

Background: p53 gene is the most commonly mutated gene in lung cancer. p53 mutation results in insensitivity of cells when exposed to chemotherapy. It has been reported that adenovirus-mediated wild-type p53 gene transfection into lung cancer cells can enhance the cytotoxic effect of anti-cancer drugs. The aim of this study is to evaluate the effects of domestic recombinant adenovirus-p53 (Ad-p53, Gendicine) on growth and chemosensitivity of human lung adenocarcinoma cell lines., Methods: Human lung adenocarcinoma cell lines GLC-82 (including mutant p53) and A549 (including wild-type p53) were treated with Ad-p53, cisplatin (DDP) or Ad-p53+DDP respectively. p53 expression was detected by Western blot. The cell growth inhibition was assessed by MTT, and cell cycle and apoptosis were detected by flow cytometry., Results: High-level p53 expression was detected in Ad-p53 infected GLC-82 and A549 cells by Western blot. There was a dose-dependent and time-dependent inhibition of cell proliferation by Ad-p53. After combined treatment with Ad-p53 (100MOI) and DDP (0.5mg/L) for 72h, the growth inhibition rate of A549 cells was 43.13%±0.72%, which was significantly higher than that in Ad-p53 group ( 23.44%±0.54%, P < 0.001) and DDP group (14.17%±1.39%, P < 0.001); and the growth inhibition rate of GLC-82 cells was 63.73%±0.92%, which was significantly higher than that in Ad-p53 group ( 41.51%±0.59%, P < 0.001) and DDP group (56.11%±1.12%, P < 0.001). Combined administration of Ad-p53 and DDP remarkably arrested A549 and GLC-82 cells in G0-G1, and cells in S phase significantly decreased. Meanwhile the apoptotic rate of A549 cells was 28.99%±1.07% in Ad-p53+DDP group, which was significantly higher than that in Ad-p53 group (15.35%±1.31%, P < 0.001) and DDP group (1.74%±0.77%, P < 0.001). The apoptotic rate of GLC-82 cells was 62.98%±2.43% in Ad-p53+DDP group, which was significantly higher than that in Ad-p53 group (20.88%±0.71%, P < 0.001) and DDP group (6.91%±1.52%, P < 0.001)., Conclusions: Ad-p53 (Gendicine) can inhibit the growth of human lung adenocarcinoma cell lines irrespective of the status of endogenous p53 gene. Its combination with DDP may significantly enhance the chemosensitivity of human lung adenocarcinoma cells to DDP.