中草药干预糖尿病肾病炎症的作用

随着糖尿病发病率逐年升高,糖尿病肾病成为导致慢性肾脏疾病和终末期肾脏疾病的主要原因。而目前控制血糖及抑制肾素-血管紧张素系统的药物治疗,并不能有效防止糖尿病肾病进展。近年来发现,慢性低水平炎症和免疫系统激活在糖尿病性肾病的发生及发展中起着至关重要的作用。明确糖尿病肾病进展中的炎症机制将有助于确定新的潜在靶点及研发抗炎治疗策略。越来越多的证据表明,中药治疗可以有效改善糖尿病性肾病的高血糖和蛋白尿,并能延缓其进展成为终末期肾病。糖尿病肾病动物实验和体外研究证实中药复方、中草药提取物和中药单体具有调节炎症介质的作用。本文旨在归纳总结文献中与糖尿病肾病肾损伤相关的炎症分子和途径,并探讨中草药靶向抗炎治疗糖尿病肾病的作用。     

微生物发酵中草药的研究现状

中草药作为天然传统药物,具有纯天然、无药残、无抗药性和毒副作用小等特点,在临床医疗和日常保健中被广泛使用。微生物发酵中草药过程中,中草药经微生物产生的酶作用后,细胞壁中的纤维素、木质素等物质被降解,其活性成分得以释放;中草药活性成分酶解为小分子物质,增强药效以利于机体消化吸收。部分中草药经发酵可以降低其毒性,减少毒副作用,甚至产生新活性物质。同时中草药中的某些成分可促进微生物的生长繁殖,由此可见中草药与微生物协同作用、相辅相成。本文从发酵中草药的优势、常用微生物、应用现状、存在的问题和关键因素等方面进行综述,并对中草药发酵的应用前景进行展望。相信随着发酵技术的成熟和中草药的现代化发展,微生物发酵中草药将具有更广阔的发展潜力和应用价值。     

Role of the unfolded protein response in determining the fate of tumor cells and the promise of multi-targeted therapies

Although there have been advances in our understanding of carcinogenesis and development of new treatments, cancer remains a common cause of death. Many regulatory pathways are incompletely understood in cancer development and progression, with a prime example being those related to the endoplasmic reticulum (ER). The pathological sequelae that arise from disruption of ER homeostasis are not well defined. The ER is an organelle that is responsible for secretory protein biosynthesis and the quality control of protein folding. The ER triggers an unfolded protein response (UPR) when misfolded proteins accumulate, and while the UPR acts to restore protein folding and ER homeostasis, this response can work as a switch to determine the death or survival of cells. The treatment of cancer with agents that target the UPR has shown promising outcomes. The UPR has wide crosstalk with other signaling pathways. Multi-targeted cancer therapies which target the intersections within signaling networks have shown synergistic tumoricidal effects. In the present review, the basic cellular and signaling pathways of the ER and UPR are introduced; then the crosstalk between the ER and other signaling pathways is summarized; and ultimately, the evidence that the UPR is a potential target for cancer therapy is discussed. Regulation of the UPR downstream signaling is a common therapeutic target for different tumor types. Tumoricidal effects achieved from modulating the UPR downstream signaling could be enhanced by phosphodiesterase 5 (PDE5) inhibitors. Largely untapped by Western medicine for cancer therapies are Chinese herbal medicines. This review explores and discusses the value of some Chinese herbal extracts as PDE5 inhibitors.     

Potential agents for cancer and obesity treatment with herbal medicines from the green garden

Many classes of bioactive drug-like molecules derived from traditional herbal plants are becoming attractive as alternative medicines for the treatment of severe chronic diseases such as cancer and obesity. A set of chemically synthesized drugs that is capable of both inhibiting cancer growth and reducing body weight for treatment of obesity have severe side effects including nausea, vomiting, diarrhea as well as producing increased blood pressure and headache, respectively. For decades, drug candidates from herbal plants have been considered as potential therapeutic agents because they are generally safer, less toxic, and have fewer lethal side effects than chemically synthesized or semi-synthetic drugs. Understanding the key factors affecting pharmacological effects and clinical outcomes has been a critical theme of natural product research. However, standardized sample preparation methods, well-controlled scientific studies, and validation studies are needed before herbal therapeutics can be introduced into the global market. This review will address the current advances in using traditional herbal plants, including the pharmacological effects and the challenges faced during the development of new drugs. The safety issues associated with toxicity and the effectiveness of the herbs in specific diseases such as cancer and obesity are also discussed.     

低剂量化疗联合中药抗血管生成作用的研究进展

自从八十年代初Folkman提出肿瘤生长依赖于新血管生成的理论,抗血管生成治疗已逐渐成为肿瘤研究的热点和肿瘤治疗的新策略。对抗血管生成治疗的深入研究也使人们对许多细胞毒化疗药物的功能活性有了新的审视,近期一些国外研究表明降低化疗药物的剂量可特异地杀伤新生肿瘤血管内皮细胞,利用化疗药物的这一新靶点,采取合理的给药方式和计划,可能帮助解决常规高剂量化疗引起的毒副作用和耐药性的难题。我国传统的中医药在肿瘤诊治上已经积累了许多宝贵的经验,对这些初步筛选出采的抗肿瘤中药借助现代技术进行精细分析、模拟修饰和药理机制研究,发现我国传统中药提取物中许多有效成分显示出了抗血管生成作用,将其与低剂量化疗联合应用也显示出良好抑瘤效果,同时毒副作用小,患者生存质量提高,因此这种联合疗法为晚期肿瘤患者提供了一种新的安全有效的治疗途径,本文对目前低剂量化疗与中药联合应用的抗肿瘤血管生成机制及应用前景作一综述。     

Chinese herbal medicines for the treatment of type A H1N1 influenza: a systematic review of randomized controlled trials

Background

Chinese herbs are thought to be effective for type A H1N1 influenza. Series of Chinese herbs have been authorized recommended by the Chinese government, and until now a number of clinical trials of Chinese herbs for H1N1 influenza have been conducted. However, there is no critically appraised evidence such as systematic reviews or meta-analyses on potential benefits and harms of medicinal herbs for H1N1 influenza to justify their clinical use and their recommendation.

Methods and Findings

CENTRAL, MEDLINE, EMBASE, CBM, CNKI, VIP, China Important Conference Papers Database, China Dissertation Database, and online clinical trial registry websites were searched for published and unpublished randomized controlled trials (RCTs) of Chinese herbs for H1N1 influenza till 31 August, 2011. A total of 26 RCTs were identified and reviewed. Most of the RCTs were of high risk of bias with flawed study design and poor methodological quality. The combination of several Chinese herbal medicines with or without oseltamivir demonstrated positive effect on fever resolution, relief of symptoms, and global effectiveness rate compared to oseltamivir alone. However, only one herbal medicine showed positive effect on viral shedding. Most of the trials did not report adverse events, and the safety of herbal medicines is still uncertain.

Conclusions

Some Chinese herbal medicines demonstrated potential positive effect for 2009 type A H1N1 influenza; however, due to the lack of placebo controlled trial and lack of repeated test of the intervention, we could not draw confirmative conclusions on the beneficial effect of Chinese herbs for H1N1 influenza. More rigorous trials are warranted to support their clinical use.     

生物肽降压作用机制及定量构效关系的研究

高血压是心脑血管疾病的首要危险因素,严重威胁着人类的生命健康。生物肽能有效预防和治疗高血压,并且具有安全可靠、作用多靶点等特点。大量的研究表明生物肽存在多种降压作用机制,深入研究降压机制可为中药治疗高血压提供新思路。本文综述了近年来生物肽潜在的降压机制,并探索其定量构效关系,旨在为中药药效组分的研究以及相关药物设计和筛选提供理论指导。     

Use of chemosensitization to overcome fludioxonil resistance in Penicillium expansum

Aim: To overcome fludioxonil resistance of Penicillium expansum, a mycotoxigenic fungal pathogen causing postharvest decay in apple, by using natural phenolic chemosensitizing agents. Methods and Results: Fludioxonil‐resistant mutants of P. expansum were co‐treated with different oxidising and natural phenolic agents. Resistance was overcome by natural phenolic chemosensitizing agents targeting the oxidative stress–response pathway. These agents also augmented effectiveness of the fungicide, kresoxim‐methyl. Results indicated that alkyl gallates target mitochondrial respiration and/or its antioxidation system. Fungal mitochondrial superoxide dismutase (Mn‐SOD) plays a protective role against alkyl gallates. Conclusions: Natural chemosensitizing agents targeting the oxidative stress–response system, such as Mn‐SOD, can synergize commercial fungicides. Significance and Impact of the Study: Redox‐active compounds can serve as potent chemosensitizing agents to overcome resistance and lower effective dosages of fungicides. This can reduce costs with coincidental lowering of environmental and health risks.     

中药治疗骨质疏松症的现状及展望

采用西药治疗骨质疏松症存在着毒性大、价格昂贵等问题,迄今为止还没一个有效且毒副作用小的骨质疏松症治疗药物。中国古代本草书籍中记载着大量对骨科疾患有疗效的中草药,积累了大量的临床经验。从中草药中寻找抗骨质疏松症药物成为研究热点课题,在中医理论指导下开发此类中药是切实可行的。     

Subchronic methionine load induces oxidative stress and provokes biochemical and histological changes in the rat liver tissue

Melatonin has antitumor activity via several mechanisms including its anti-proliferative and pro-apoptotic effects. Moreover, it has been proven that melatonin in combination with chemotherapeutic agents enhances chemotherapy-triggered apoptosis in several types of cancer. Therefore, this study was intended to evaluate whether melatonin is able to strengthen the anti-cancer potential of different chemotherapeutic drugs in human colorectal adenocarcinoma HT–29 cells. We found that treatment with 20 µM cisplatin (CIS) or 1 mM 5-fluorouracil (5-FU) for 72 h induced a decrease in HT-29 cell viability. Furthermore, 1 mM melatonin significantly (P < 0.05) increased the cytotoxic effects of 5-FU. Likewise, simultaneous stimulation with 1 mM melatonin and 1 mM 5-FU significantly (P < 0.05) enhanced the ratio of cells with an overproduction of intracellular reactive oxygen species and substantially augmented the population of apoptotic cells compared to the treatment with 5-FU alone. Nonetheless, melatonin only displayed moderate chemosensitizing effects in CIS-treated HT-29 cells, as suggested by a slight increment in the fraction of early apoptotic cells that was observed only after 48 h. Consistently, co-stimulation of HT-29 cells with 20 µM CIS or 1 mM 5-FU in the presence of 1 mM melatonin further increased caspase-3 activation. Apart from this, the cytostatic activity displayed by CIS due to S phase arrest was not affected by concomitant stimulation with melatonin. Overall, our results indicate that melatonin increases the sensitivity of HT-29 cells to 5-FU treatment and, consequently, the indolamine could be potentially applied to colorectal adenocarcinoma treatment as a potent chemosensitizing agent.     

Pharmacogenomic and molecular docking studies on the cytotoxicity of the natural steroid wortmannin against multidrug-resistant tumor cells

Wortmannin is a cytotoxic compound derived from the endophytic fungi Fusarium oxysporum, Penicillium wortmannii and Penicillium funiculosum that occurs in many plants, including medicinal herbs. The rationale to develop novel anticancer drugs is the frequent development of tumor resistance to the existing antineoplasic agents. Therefore, it is mandatory to analyze resistance mechanisms of novel drug candidates such as wortmannin as well to bring effective drugs into the clinic that have the potential to bypass or overcome resistance to established drugs and to substantially increase life span of cancer patients. In the present project, we found that P-glycoprotein-overexpressing tumor cells displaying the classical multidrug resistance phenotype toward standard anticancer drugs were not cross-resistant to wortmannin. Furthermore, three point-mutated PIK3CA protein structures revealed similar binding energies to wortmannin than wild-type PIK3CA. This protein is the primary target of wortmannin and part of the PI3K/AKT/mTOR signaling pathway. PIK3CA mutations are known to be associated with worse response to therapy and shortened its activity toward wild-type and mutant PIK3CA with similar efficacy.     

A framework for assessing the risk of resistance for anti-malarials in development

ABSTRACT: Resistance is a constant challenge for anti-infective drug development. Since they kill sensitive organisms, anti-infective agents are bound to exert an evolutionary pressure toward the emergence and spread of resistance mechanisms, if such resistance can arise by stochastic mutation events. New classes of medicines under development must be designed or selected to stay ahead in this vicious circle of resistance control. This involves both circumventing existing resistance mechanisms and selecting molecules which are resilient against the development and spread of resistance. Cell-based screening methods have led to a renaissance of new classes of anti-malarial medicines, offering us the potential to select and modify molecules based on their resistance potential. To that end, a standardized in vitro methodology to assess quantitatively these characteristics in Plasmodium falciparum during the early phases of the drug development process has been developed and is presented here. It allows the identification of anti-malarial compounds with overt resistance risks and the prioritization of the most robust ones. The integration of this strategy in later stages of development, registration, and deployment is also discussed.     

Profiling of the charged metabolites of traditional herbal medicines using capillary electrophoresis time-of-flight mass spectrometry

The quantification of a small number of bioactive components in herbal medicines is often inadequate when attempting to elucidate a medicine’s biological effects. Despite rapid advances in analytical technologies, obtaining comprehensive metabolomic profiles of herbal medicines remains difficult, due to the complexity of natural product mixtures. Toki-Shakuyaku-San is a Chinese medicine used widely to treat gynecological and obstetric disorders, such as infertility, dysmenorrhea, toxemia during pregnancy and neural dysfunction. It consists of Angelica acutiloba Radix (Toki), Cnidium officinale Rhizoma (Senkyu), Paeonia lactiflora Radix (Shakuyaku), Atractylodes lancea Rhizoma (Sojutsu), Alisma orientale Rhizoma (Takusha) and Poria cocos Hoelen (Bukuryo). To elucidate the composition of these herbal medicines individually, we conducted non-targeted profiling analyses of extracts of these herbs using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS), which allows the simultaneous quantification of hundreds of charged metabolites. In total, 737 ± 183.1 (average ± SD) metabolite-derived features were observed, and of these, 119 metabolites were identified. Score plots of principal component analysis (PCA) showed a clear cluster including Shakuyaku, Bukuryo, and Sojutsu, while the other three herbs were distributed over PCA spaces. Loading plots revealed that amino acids and shikimate-derived alkaloids were the predominant metabolite constituents. Hierarchical clustering analysis revealed that few clusters overlapped in the herbal medicines tested. This report is the first demonstration of the characterization of a herbal medicine using large-scale metabolomic analysis, which is complementary to traditional quality control methods.     

Drug resistance mechanisms and novel drug targets for tuberculosis therapy

Drug-resistant tuberculosis (TB) poses a significant challenge to the successful treatment and control of TB worldwide. Resistance to anti-TB drugs has existed since the beginning of the chemotherapy era. New insights into the resistant mechanisms of anti-TB drugs have been provided. Better understanding of drug resistance mechanisms helps in the development of new tools for the rapid diagnosis of drug-resistant TB. There is also a pressing need in the development of new drugs with novel targets to improve the current treatment of TB and to prevent the emergence of drug resistance in Mycobacterium tuberculosis. This review summarizes the anti-TB drug resistance mechanisms, furnishes some possible novel drug targets in the development of new agents for TB therapy and discusses the usefulness using known targets to develop new anti-TB drugs. Whole genome sequencing is currently an advanced technology to uncover drug resistance mechanisms in M. tuberculosis. However, further research is required to unravel the significance of some newly discovered gene mutations in their contribution to drug resistance.     

中成药乙醚提取液对Raji细胞的EPSTEIN-BARR病毒早期抗原的诱导

应用Raji细胞系统研究了350种中成药,发现保赤散、小儿脐风散,铁娃丹,舟车丸,鹭鸶咯丸,时疫止泻丸、清心滚痰丸和八宝坤顺丸等8种中成药的乙醚提取液,对Raji细胞的EB病毒早期抗原(EA)有诱导作用,并讨论了这些中成药与肿瘤发生的关系。     

The role of topoisomerase II in drug resistance.

The conventional laboratory approach to study the mechanisms of drug resistance has been the selection of drug-resistant cell lines by continuous exposure to cytotoxic agents. Such lines, which are selected for resistance to a single agent, frequently display cross-resistance to a number of cytotoxic agents that are unrelated in both structure and proposed mechanism of action. Multidrug-resistant cells display reduced drug accumulation, which is the result of overexpression of a surface glycoprotein (P170). Although resistance to multiple antitumor agents is a common clinical problem in the treatment of cancer, the precise role of the P-glycoprotein-mediated mechanism in human tumors remains to be established. Many alterations in multidrug-resistant cells selected in vitro have been identified. The concomitant expression of multiple phenotypic differences, which appear to be favored by continued and prolonged drug exposure, makes analysis of critical individual resistance pathways more difficult. However, multiple factors may also be involved in the development of clinical resistance. Recent studies have identified alterations in DNA topoisomerase II activity and function as an alternative mechanism that contributes to the multidrug-resistance phenomenon or is responsible for a different type of drug resistance. The precise nature of these changes remains unclear. Available evidence supports the view that expression of the enzyme is an important determinant of cell sensitivity to DNA topoisomerase poisons, but that other changes involved in regulation of enzyme function and/or in the cellular processing of drug-induced DNA damage may be critical in determining the differential pattern of cell response to antitumor agents.     

Drug Resistance in Glioblastoma: A Mini Review

Glioblastoma multiforme (GBM) is recognized as the most common and lethal form of central nervous system cancer. Currently used surgical techniques, chemotherapeutic agents, and radiotherapy strategies have done very little in extending the life expectancies of patients diagnosed with GBM. The difficulty in treating this malignant disease lies both in its inherent complexity and numerous mechanisms of drug resistance. In this review, we summarize several of the primary mechanisms of drug resistance. We reviewed available published literature in the English language regarding drug resistance in glioblastoma. The reasons for drug resistance in glioblastoma include drug efflux, hypoxic areas of tumor cells, cancer stem cells, DNA damage repair, and miRNAs. Many potential therapies target these mechanisms, including a series of investigated alternative and plant-derived agents. Future research and clinical trials in glioblastoma patients should pursue combination of therapies to help combat drug resistance. The emerging new data on the potential of plant-derived therapeutics should also be closely considered and further investigated.     

Design and Optimization of Peptide Ligands to Target Breast Cancer-Positive HER2 by Grafting and Truncation of MIG6 Peptide

The human epidermal growth factor receptor 2 (EGFR2 or HER2) has been established as a therapeutic target for HER2-positive breast cancer. Although a number of small-molecule agents have been developed to target HER2, many adverse drug reactions (ADRs) such as side effects and drug resistance are frequently observed in the chemotherapeutics. Previously, peptides derived from MIG6 protein, a natural negative regulator of EGFR and HER2, have been shown to destabilize EGFR dimerization (Zhang et al. 2007). Here, we grafted a MIG6 fragment (³³⁶KSLPSYLNGVMPPTQSFAPDPKYVSS³⁶¹) in crystal interaction site from EGFR to HER2, truncated the fragment to obtain a short segment (³⁴⁶MPPTQSFA³⁵³) with reserved binding capability (K _d = 121.6 ± 14.5 μM) to HER2 kinase domain, and optimized the segment to improve its affinity for the domain. Consequently, three peptides (MLPNQSFA, MFPNQSFA and MFPYQSFA) were successfully designed to exhibit moderate or high potency (K _d = 78.0 ± 9.8, 28.7 ± 3.9 and 65.1 ± 7.2 μM, respectively) towards HER2 kinase domain, which are expected to destabilize HER2 dimerization and then suppress the kinase activation in breast cancer.