An optical study of drug resistance detection in endometrial cancer cells by dynamic and quantitative phase imaging

Platinum chemosensitivity detection plays a vital role during endometrial cancer treatment because chemotherapy responses have profound influences on patient's prognosis. Although several methods can be used to detect drug resistance characteristics, studies on detecting drug sensitivity based on dynamic and quantitative phase imaging of cancer cells are rare. In this study, digital holographic microscopy was applied to distinguish drug‐resistant and nondrug‐resistant endometrial cancer cells. Based on the reconstructed phase images, temporal evolutions of cell height (CH), cell projected area (CPA) and cell volume were quantitatively measured. The results show that change rates of CH and CPA were significantly different between drug‐resistant and nondrug‐resistant endometrial cancer cells. Furthermore, the results demonstrate that morphological characteristics have the potential to be utilized to distinguish the drug sensitivity of endometrial cancer cells, and it may provide new perspectives to establish optical methods to detect drug sensitivity and guide chemotherapy in endometrial cancer.      

结核分枝杆菌的耐药基因及其相关分子机制

结核分枝杆菌原发性和继发性耐药是当前控帝】和治疗结核病面临的重要问题,随着分子遗传学的发展,已经阐明了结核分枝杆菌耐药的分子基础是染色体的突变,影响了药靶本身或激活了药物前体的细菌酶,造成MTB的耐药。本文主要就MTB对其常用药物的耐药机制展开讨论,以便正确认识MTB对不同药物的耐药机制,建立快速检测耐药结核分枝杆菌基因型的分子生物学方法。     

结核分枝杆菌的耐药基因及其相关分子机制

结核分枝杆菌原发性和继发性耐药是当前控制和治疗结核病面临的重要问题,随着分子遗传学的发展,已经阐明了结核分枝杆菌耐药的分子基础是染色体的突变,影响了药靶本身或激活了药物前体的细菌酶,造成MTB的耐药。本文主要就MTB对其常用药物的耐药机制展开讨论,以便正确认识MTB对不同药物的耐药机制,建立快速检测耐药结核分枝杆菌基因型的分子生物学方法。     

Targeting head and neck tumoral stem cells: From biological aspects to therapeutic perspectives

Head and neck squamous cell cancer(HNSCC) is the sixth most common cancer in the world. Effective therapeutic modalities such as surgery, radiation, chemotherapy and combinations of each are used in the management of the disease. In most cases, treatment fails to obtain total cancer cure. In recent years, it appears that one of the key determinants of treatment failure may be the presence of cancer stem cells(CSCs) that escape currently available therapies. CSCs form a small portion of the total tumor burden but may play a disproportionately important role in determining outcomes. CSCs have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. A large body of evidence points to the fact that CSCs are particularly resistant to radiotherapy and chemotherapy. In HNSCC, CSCs have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In the light of such observations, the present review summarizes biological characteristics of CSCs in HNSCC, outlines targeted strategies for the successful eradication of CSCs in HNSCC including targeting the self-renewal controlling pathways, blocking epithelial mesenchymal transition, niche targeting, immunotherapy approaches and highlights the need to better understand CSCs biology for new treatments modalities.     

CRISPR technology: A versatile tool to model,screen, and reverse drug resistance in cancer

BackgroundDrug resistance is a serious challenge in cancer treatment that can render chemotherapy a failure. Understanding the mechanisms behind drug resistance and developing novel therapeutic approaches are cardinal steps in overcoming this issue. Clustered regularly interspaced short palindrome repeats (CRISPR) gene-editing technology has proven to be a useful tool to study cancer drug resistance mechanisms and target the responsible genes. In this review, we evaluated original research studies that used the CRISPR tool in three areas related to drug resistance, namely screening resistance-related genes, generating modified models of resistant cells and animals, and removing resistance by genetic manipulation. We reported the targeted genes, study models, and drug groups in these studies. In addition to discussing different applications of CRISPR technology in cancer drug resistance, we analyzed drug resistance mechanisms and provided examples of CRISPR’s role in studying them. Although CRISPR is a powerful tool for examining drug resistance and sensitizing resistant cells to chemotherapy, more studies are required to overcome its disadvantages, such as off-target effects, immunotoxicity, and inefficient delivery of CRISPR/cas9 into the cells.     

2014—2015年大连市伤寒沙门菌耐药性及分子分型研究

目的 了解大连市伤寒沙门菌的药物敏感情况及同源性特点,为临床用药和疾病预防提供科学指导。方法 选择15种抗生素、运用微量肉汤稀释法对65株伤寒沙门菌进行抗生素敏感试验;采用脉冲场凝胶电泳（PFGE）法进行聚类分析。结果 65株伤寒沙门菌对阿奇霉素100.00%敏感,对红霉素100.00%耐药,对其他13种药物有不同程度的耐药率（1.54%~73.85%）。发现1株多重耐药菌株。65株菌共产生41种PFGE带型,其中8株菌表现为同一型别。结论 大连地区临床分离伤寒沙门菌耐药形势严峻;聚类分析结果表明其PFGE型别较多,而且其中存在着优势菌株。     

Characterization and performance of a near-infrared 2-deoxyglucose optical imaging agent for mouse cancer models

Malignant neoplasms exhibit an elevated rate of glycolysis over normal cells. This characteristic can be exploited for optical imaging of tumors in mice. A near-infrared fluorophore, IRDye 800CW, emission maximum 794 nm, was conjugated to 2-deoxyglucose (2-DG). An immunofluorescent cell-based assay was used to evaluate specificity and sensitivity of the conjugate in cultured cell monolayers. Dose-dependent uptake was established with increasing concentrations of IRDye 800CW 2-DG for epithelial and prostate carcinomas. IRDye 800CW 2-DG was specifically blocked by an antibody against GLUT1 glucose transporter, and by excess unlabeled 2-DG or d-glucose. Signal was increased by a phorbol ester activator of glucose transport. Fluorescence microscopy data confirmed localization of the conjugate in the cytoplasm. Subsequent in vivo studies optimized dose, clearance, and timing for signal capture in nude mouse xenografts. In all cases, tumors were clearly imaged with good signal-to-noise characteristics. These data indicate that IRDye 800CW 2-DG is a broadly applicable optical imaging agent for in vivo imaging of neoplasms in mice.     

副溶血性弧菌肠细菌基因间共有重复序列-PCR分子分型和耐药性、血清型研究

目的对副溶血性弧菌进行ERIC-PCR分子分型、耐药性和血清型相关性研究。方法肠细菌基因间共有重复序列（ERIC）为引物,对40株菌株基因组DNA进行扩增,得到DNA指纹图谱,并利用SPSS13.0统计软件对DNA扩增图谱进行分析,做出聚类图从而分型,并与菌株血清型、耐药性比较分析。结果40株菌用ERIC-PCR分为5个型,分辨力指数为（DI）为0.5;血清分型分为4个型;对8种抗生素中的萘啶酸、头孢噻亏、头孢西丁出现了不同程度的耐药。耐药菌株均出现在ERIC-PCR方法分型A型和血清分型O3型中。结论研究显示ERIC-PCR方法可以用于该菌分型分析,具有较好的分型能力。血清分型与ERIC-PCR方法分型一致。通过ERIC-PCR分型的树状图和血清分型结果推断,血清型O3群菌株很可能起源于血清型O1群菌株,血清型O3群和O1群密切相关。     

A mechanism of drug resistance to tamoxifen in breast cancer

Drug resistance to tamoxifen (Tam) is a significant clinical problem but the mechanism through which this occurs remains elusive. We have developed a number of xenograft models of Tam-stimulated growth that model breast cancer progression using estrogen receptor positive MCF-7 or T47D breast cancer cells. When estrogen-stimulated T47D:E2 tumors are treated long term with Tam, Tam-stimulated tumors develop (T47D:Tam) that are stimulated by both estrogen and Tam. When HER-2/neu status is determined, it is clear that the T47D:Tam tumors express significantly higher levels of HER-2/neu protein by immunohistochemistry and mRNA as measured by real-time RT-PCR. The T47D:Tam tumors also express higher levels of estrogen receptor and progesterone receptor protein than their estrogen-stimulated T47D:E2 counterparts. We compared out results to the MCF-7 model of Tam-stimulated growth. The MCF-7:Tam ST (estrogen- and Tam-stimulated) and MCF-7:Tam LT (estrogen-inhibited, Tam-stimulated) were bilaterally transplanted to account for any mouse to mouse variation and characteristic growth patterns were observed. TUNEL staining was performed on MCF-7:Tam LT treated with either estrogen or Tam and it was concluded that estrogen-inhibited tumor growth was a result of increased apoptosis. Three phases of tumor progression are described that involve increases in HER-2/neu expression, de-regulation of estrogen receptor expression and increases in apoptosis which in concert determine the phenotype of drug resistance to Tam.     

Multiple roles of mothers against decapentaplegic homolog 4 in tumorigenesis,stem cells,drug resistance,and cancer therapy

The transforming growth factor(TGF)-βsignaling pathway controls many cellular processes,including proliferation,differentiation,and apoptosis.Abnormalities in the TGF-βsignaling pathway and its components are closely related to the occurrence of many human diseases,including cancer.Mothers against decapentaplegic homolog 4(Smad4),also known as deleted in pancreatic cancer locus 4,is a typical tumor suppressor candidate gene locating at q21.1 of human chromosome 18 and the common mediator of the TGF-β/Smad and bone morphogenetic protein/Smad signaling pathways.It is believed that Smad4 inactivation correlates with the development of tumors and stem cell fate decisions.Smad4 also interacts with cytokines,miRNAs,and other signaling pathways,jointly regulating cell behavior.However,the regulatory function of Smad4 in tumorigenesis,stem cells,and drug resistance is currently controversial.In addition,Smad4 represents an attractive therapeutic target for cancer.Elucidating the specific role of Smad4 is important for understanding the mechanism of tumorigenesis and cancer treatment.Here,we review the identification and characterization of Smad4,the canonical TGF-β/Smad pathway,as well as the multiple roles of Smad4 in tumorigenesis,stem cells,and drug resistance.Furthermore,we provide novel insights into the prospects of Smad4-targeted cancer therapy and the challenges that it will face in the future.     

Integrating cell-cycle progression, drug penetration and energy metabolism to identify improved cancer therapeutic strategies

The effectiveness of chemotherapeutic drugs in tumors is reduced by multiple effects including drug diffusion and variable susceptibility of local cell populations. We hypothesized that quantifying the interactions between drugs and tumor microenvironments could be used to identify more effective anti-cancer strategies. To test this hypothesis we created a mathematical model that integrated intracellular metabolism, nutrient and drug diffusion, cell-cycle progression, cellular drug effects, and drug pharmacokinetics. To our knowledge, this is the first model that combines these elements and has coupled them to experimentally derived parameters. Drug cytotoxicity was assumed to be cell-cycle phase specific, and progression through the cell cycle was assumed to be dependent on ATP generation. The model consisted of a coupled set of nonlinear partial differential, ordinary differential and algebraic equations with an outer free boundary, which was solved using orthogonal collocation on a moving grid of finite elements. Model simulations showed the existence of an optimum drug diffusion coefficient: a low diffusivity prevents effective penetration before the drug is cleared from the blood and a high diffusivity limits drug retention. This result suggests that increasing the molecular weight of the anti-cancer drug paclitaxel from 854 to approximately 20,000 by nano-particle conjugation would improve its efficacy. The simulations also showed that fast growing tumors are less responsive to therapy than are slower tumors with more quiescent cells, demonstrating the competing effects of regrowth and cytotoxicity. The therapeutic implications of the simulation results are that (1) monolayer cultures are inadequate for accurately determining therapeutic effects in vitro, (2) decreasing the diffusivity of paclitaxel could increase its efficacy, and (3) measuring the proliferation fraction in tumors could enhance the prediction of therapeutic efficacy.     

Noninvasive in vivo cell tracking using molecular imaging: A useful tool for developing mesenchymal stem cell-based cancer treatment

Mounting evidence has emphasized the potential of cell therapies in treating various diseases by restoring damaged tissues or replacing defective cells in the body. Cell therapies have become a strong therapeutic modality by applying noninvasive in vivo molecular imaging for examining complex cellular processes, understanding pathophysiological mechanisms of diseases, and evaluating the kinetics/dynamics of cell therapies. In particular, mesenchymal stem cells (MSCs) have shown promise in recent years as drug carriers for cancer treatment. They can also be labeled with different probes and tracked in vivo to assess the in vivo effect of administered cells, and to optimize therapy. The exact role of MSCs in oncologic diseases is not clear as MSCs have been shown to be involved in tumor progression and inhibition, and the exact interactions between MSCs and specific cancer microenvironments are not clear. In this review, a multitude of labeling approaches, imaging modalities, and the merits/demerits of each strategy are outlined. In addition, specific examples of the use of MSCs and in vivo imaging in cancer therapy are provided. Finally, present limitations and future outlooks in terms of the translation of different imaging approaches in clinics are discussed.     

Association of multiple drug resistance-1 gene polymorphism with multiple drug resistance in breast cancer patients from an ethnic Saudi Arabian population

Chemotherapy has been used widely to treat cancer, both as a systemic therapy and as a local treatment. Unfortunately, many types of cancer are still refractory to chemotherapy. The mechanisms of anticancer drug resistance have been extensively explored but have not been fully characterized. This study analyzed the occurrences of polymorphism (SNP) in the MDR1 gene in breast cancer patients and determined a possible association with chemotherapy. The study group included one hundred breast carcinoma patients who subsequently received chemotherapy (the regimen generally consisted of commonly used drugs such as cyclophosphamide, adriamycin, 5-fluorouracil, docetaxel and their combinations). Blood samples from 100 healthy individuals are used, as controls were also genotyped for the MDR1 gene. This investigation revealed a significant correlation with response to various regimens of chemotherapy showing a low response to therapy with the CT/TT genotype at (exon 12) 1236 codon (p < 0.001). These findings demonstrate, for the first time, that the polymorphisms in (exon 12) 1236 codon of the MDR1 gene greatly influence the drug response in patients from the Arab population of Saudi Arabia.     

Salvianolic acid B suppresses EMT and apoptosis to lessen drug resistance through AKT/mTOR in gastric cancer cells

The drug resistance of tumor cells greatly reduces the efficacy of chemotherapy drugs in gastric cancer. Salvianolic acid B (Sal-B) is considered as a chemopreventive agent which suppresses oxidative stress and apoptosis. Therefore, the study aims to clarify the mechanism of Sal-B in drug-resistant gastric cancer cells. CCK8 assay analyzed cell viabilities after GES1, AGS and AGS/DDP cells were respectively treated by Sal-B of different concentration or after AGS/DDP cells were disposed by cisplatin (DDP) in different concentration. The colony formation, ROS generation, apoptosis, migration, invasion and EMT marker proteins were respectively analyzed through formation assay, ROS kits, TUNNEL staining, Wound healing, Transwell assays and Western blot. The results demonstrated that Sal-B acted alone or in synergy with DDP to reduce cell viabilities, initiate ROS generation, promote cell apoptosis, as well as decrease migration, invasion and EMT in AGS and AGS/DDP cells. AKT activator and mTOR activator significantly reversed the above effects of Sal-B. Collectively, Sal-B regulated proliferation, EMT and apoptosis to reduce the resistance to DDP via AKT/mTOR pathway in DDP-resistant gastric cancer cells. Sal-B could be a potential anti-drug resistance agent to chemotherapy in gastric cancer.     

Prolonged in vivo functional assessment of the mouse oviduct using optical coherence tomography through a dorsal imaging window

The oviduct (or fallopian tube) serves as an environment for gamete transport, fertilization and preimplantation embryo development in mammals. Although there has been increasing evidence linking infertility with disrupted oviduct function, the specific roles that the oviduct plays in both normal and impaired reproductive processes remain unclear. The mouse is an important mammalian model to study human reproduction. However, most of the current analyses of the mouse oviduct rely on static histology or 2D visualization, and are unable to provide dynamic and volumetric characterization of this organ. The lack of imaging access prevents longitudinal live analysis of the oviduct and its associated reproductive events, limiting the understanding of mechanistic aspects of fertilization and preimplantation pregnancy. To address this limitation, we report a 3D imaging approach that enables prolonged functional assessment of the mouse oviduct in vivo. By combining optical coherence tomography with a dorsal imaging window, this method allows for extended volumetric visualization of the oviduct dynamics, which was previously not achievable. The approach is used for quantitative analysis of oviduct contraction, spatiotemporal characterization of cilia beat frequency and longitudinal imaging. This new approach is a useful in vivo imaging platform for a variety of live studies in mammalian reproduction.      

Evaluation of novel Saquinavir analogs for resistance mutation compatibility and potential as an HIV-Protease inhibitor drug

A fundamental issue related to therapy of HIV-1 infection is the emergence of viral mutations which severely limits the long term efficiency of the HIV-protease (HIV-PR) inhibitors. Development of new drugs is therefore continuously needed. Chemoinformatics enables to design and discover novel molecules analogous to established drugs using computational tools and databases. Saquinavir, an anti-HIV Protease drug is administered for HIV therapy. In this work chemoinformatics tools were used to design structural analogs of Saquinavir as ligand and molecular dockings at AutoDock were performed to identify potential HIV-PR inhibitors. The analogs S1 and S2 when docked with HIV-PR had binding energies of -4.08 and -3.07 kcal/mol respectively which were similar to that for Saquinavir. The molecular docking studies revealed that the changes at N2 of Saquinavir to obtain newly designed analogs S1 (having N2 benzoyl group at N1) and S2 (having 3-oxo-3phenyl propanyl group at N2) were able to dock with HIV-PR with similar affinity as that of Saquinavir. Docking studies and computationally derived pharmacodynamic and pharmacokinetic properties׳ comparisons at ACD/I-lab establish that analog S2 has more potential to evade the problem of drug resistance mutation against HIV-1 PR subtype-A. S2 can be further developed and tested clinically as a real alternative drug for HIV-1 PR across the clades in future.     

Engineered Fn3 protein has targeted therapeutic effect on mesothelin-expressing cancer cells and increases tumor cell sensitivity to chemotherapy

Mesothelin is a protein expressed at high levels on the cell surface in a variety of cancers, with limited expression in healthy tissues. The presence of mesothelin on tumor tissue correlates with increased invasion and metastasis, and resistance to traditional chemotherapies, through mechanisms that remain poorly understood. Molecules that specifically recognize mesothelin and interrupt its contribution to tumor progression have significant potential for targeted therapy and targeted drug delivery applications. A number of mesothelin-targeting therapies are in preclinical and clinical development, although none are currently approved for routine clinical use. In this work, we report the development of a mesothelin-targeting protein based on the fibronectin type-III non-antibody protein scaffold, which offers opportunities for applications where antibodies have limitations. We engineered protein variants that bind mesothelin with high affinity and selectively initiate apoptosis in tumor cells expressing mesothelin. Interestingly, apoptosis does not occur through a caspase-mediated pathway and does not require downregulation of cell-surface mesothelin, suggesting a currently unknown pathway through which mesothelin contributes to cancer progression. Importantly, simultaneous treatment with mesothelin-binding protein and chemotherapeutic mitomycin C had a greater cytotoxic effect on mesothelin-positive cells compared to either molecule alone, underscoring the potential for combination therapy including biologics targeting mesothelin.     

Automatic identification and quantitative morphometry of unstained spinal nerve using molecular hyperspectral imaging technology

Quantitative observation of nerve fiber sections is often complemented by morphological analysis in both research and clinical condition. However, existing manual or semi-automated methods are tedious and labour intensive, fully automated morphometry methods are complicated as the information of color or gray images captured by traditional microscopy is limited. Moreover, most of the methods are time-consuming as the nerve sections need to be stained with some reagents before observation. To overcome these shortcomings, a molecular hyperspectral imaging system is developed and used to observe the spinal nerve sections. The molecular hyperspectral images contain both the structural and biochemical information of spinal nerve sections which is very useful for automatic identification and quantitative morphological analysis of nerve fibers. This characteristic makes it possible for researchers to observe the unstained spinal nerve and live cells in their native environment. To evaluate the performance of the new method, the molecular hyperspectral images were captured and the improved spectral angle mapper algorithm was proposed and used to segment the myelin contours. Then the morphological parameters such as myelin thickness and myelin area were calculated and evaluated. With these morphological parameters, the three dimension surface view images were drawn to help the investigators observe spinal nerve at different angles. The experiment results show that the hyperspectral based method has the potential to identify the spinal nerve more accurate than the traditional method as the new method contains both the spectral and spatial information of nerve sections.     

转录因子及miRNA调控食管癌耐药机制研究

由于耐药性的存在,不同患者在使用相同药物时会导致治疗效果的差异.因此识别耐药性相关的关键生物学标记,有助于临床医生快速选择出适合的药物,延长患者的生存时间,对药物研发以及药物的作用机制的详细研究具有重要意义.首先在食管癌细胞系中筛选不同药物的耐药及敏感细胞系,从中找到不同药物耐药相关的基因,将这些计算得到的耐药相关基因...