抗丙型肝炎病毒药物作用靶标和小分子抑制剂研究进展

针对发病率逐年增高的丙型肝炎,目前主要依靠利巴韦林和干扰素的联合用药加以控制症状,但在治疗同时伴有明显不良反应,而且至今仍无法治愈。因此,临床上迫切需要研发出新型抗丙型肝炎病毒(HCV)药物,并且随着HCV生物学研究的快速发展,对HCV的感染和复制有了更深入的了解,加速了新药研发进程。本文综述了抗HCV药物作用靶标和新型小分子抑制剂,重点对其抑制剂的化学结构、抗HCV活性和构效关系进行了相关总结。     

Novel small molecule Raf kinase inhibitors for targeted cancer therapeutics

Aberrant activation of Raf signaling pathway is frequently found in various human tumors, it has been considered as distinct and promising molecular target for cancer therapeutics. B-Raf is most attractive drug target out of three Raf isoforms (A-Raf, B-Raf and C-Raf) because it exhibits high kinase activity due to frequent mutations in human tumors. However, most recently, it has been reported that Raf isoforms show the cross-activation in the presence of specific B-Raf inhibitors, which brings about the paradoxical p-ERK activation as well as tumor promoting effect. According to these findings, it remains controversy whether pan-Raf kinase inhibitor is more valuable and promising rather than specific B-Raf inhibitor under certain conditions in terms of cancer therapeutics. In this short review, novel Raf kinase inhibitors undergoing clinical investigation are introduced. Moreover, the paradoxical p-ERK activation is discussed with specific B-Raf inhibitors, PLX4032/4720 compounds.     

Novel therapy in multiple myeloma

Treatment in patients with multiple myeloma remain to be defined. Younger patients (defined as a cut-off level < 65 years old) will be treated with chemotherapy and transplant procedures. However, most patients > 65 years old are not candidates for this therapeutic approach and the use of intensive chemotherapy could be associated to severe toxicity. We developed an new, not-cytotoxic regimen with dexamethasone 30 mg/m², iv, days 1 to 4, all trans retinoic acid 45 mg/m², po, days 5 to 14 and interferon alfa 2a 4.5 MU, sc, daily, days 5 to 14 (DAI regimen) administered every 28 days in number of 6 cycles, at this point patients were restaging, if they showed complete response, objective response or partial response they were conducted to received thalidomide 100–200 mg po, daily and dexamethasone 10 mg/2, po days 1 to 4 at monthly intervals, for 18 months. Forty one patients were enrolled in an Phase II study. In an intent to treat analysis all patients were evaluable. Complete response was observed in 18 cases (43%), objective response in 10 patients (24%) and partial response in 5 patients (12%), overall response rate was 80%. Eight patients were considered failures. At an median of 36 months, no relapse of progression disease has been observed, thus actuarial curves at 3-years showed that event free survival is 100% and overall survival is 91%. Toxicity was mild, all patients received the planned dose in time. This regimen appear to be useful in older patients with multiple myeloma, the response rate is higher and toxicity was mild. Controlled clinical trials comparing with conventional chemotherapy will be conducted to define the role of this therapeutic approach.     

Novel targets for myeloma bone disease

Background: Multiple myeloma (MM) is a plasma cell malignancy in which osteolytic bone lesions develop in over 80% of patients. The increased bone destruction results from increased osteoclast formation and activity, which occurs adjacent to marrow sites involved with MM cells. This is accompanied by suppressed or absent osteoblast differentiation and activity, resulting in severely impaired bone formation and development of purely osteolytic lesions. Objective: The pathophysiology underlying this bone remodeling is reviewed, and potential new strategies to treat MM bone disease are discussed. Results: Recent advances in our understanding of factors involved in pathogenesis of MM bone disease have identified novel therapeutic targets. Several of these are or will be in clinical trials soon. Conclusion: Agents which target the tumor and bone-destructive process, such as the immunomodulatory drugs (IMiDs) or bortezomib, in combination with novel anti-resorptives should be effective. These combinations should be in clinical trials in the next few years. It is unclear if these treatments will be able to ‘heal’ bone lesions in MM patients.     

Novel immunomodulatory compounds in multiple myeloma

Introduction: The treatment options for patients with multiple myeloma (MM) remain limited. Immunomodulatory agents (IMiDs), such as thalidomide and lenalidomide, have changed the landscape in the treatment of patients with MM while newer IMiDs such as pomalidomide are showing promise in early clinical trials.

Areas covered: This review focuses on the biologic rationales of IMiDs and the clinical results supporting their use in MM. It includes data on the new IMiD, pomalidomide and also explores the possible utility of combining IMiDs with other agents. A PubMed search and abstracts from oncology scientific meetings (ASCO and ASH) of articles related to IMiDs and MM was conducted.

Expert opinion: IMiDs have shown clinical activity as single agents and in combination. Thalidomide was the first in class drug. Lenalidomide has a better toxicity profile than thalidomide. Pomalidomide may overcome resistance to lenalidomide indicating differences in their mechanisms of action and resistance. Molecular biomarkers may allow us to identify patients who will respond to IMiDs.     

Novel mitotic targets and their small-molecule inhibitors

With several successful anticancer drugs on the market and numerous compounds in clinical developments, antimitotic agents represent an important category of anticancer agents. However, clinical utility of the tubulin-binding agents is somewhat limited due to multiple drug resistance (MDR), poor pharmacokinetics and therapeutic index. There is ongoing need for the modulators of other intracellular targets that result in the same anti-mitotic effect without adverse effects of "traditional" tubulin binders. This review describes progress made to-date in development of novel and emerging biotargets affecting the mitotic events, and their small-molecule modulators.     

Proteasome inhibitors and modulators of angiogenesis in multiple myeloma

Survival of patients affected by Multiple Myeloma (MM), a B-cell tumor of malignant plasma cells, has dramatically improved, owing to the recent introduction of the proteasome inhibitor (PI) Bortezomib and of the immunomodulatory drugs (IMiDs). This major advance originates from accumulating knowledge on MM biology, leading to the development of drugs targeting not only MM cells, but also their microenvironment. Indeed, the disease develops as a result of genetic abnormalities and of reciprocal interactions between MM cells and the permissive BM microenvironment, which delivers growth- and pro-survival signals and confers resistance to drugs. As for solid tumors, bone marrow (BM) angiogenesis is emerging as a critical component of MM development and progression, and hence as an attractive therapeutic target for the disease. The patho-physiology of MM associated angiogenesis is complex and involves a plethora of soluble factors, cellular players and mechanisms. Moreover, the hypoxic microenvironment inside the BM might significantly contribute to the induction and maintenance of a pro-angiogenic profile, given the well-known role of hypoxia in promoting angiogenesis in all its forms. Here we present an overview of the literature focusing on the mechanisms implicated in the "angiogenic switch", which corresponds to the transition from the avascular to the vascular phase of the disease. We also review evidence on the anti-angiogenic effects of PI and IMiDs, which substantially contribute to their anti-MM activity. Finally, we summarize possible caveats and perspectives about antiangiogenic strategies that could be addressed to improve the efficacy of treatments for MM patients.     

Protein kinases as small molecule inhibitor targets in inflammation

The human kinome describes a major group of intracellular signalling molecules. In the last few years, many molecules in the group have become targets for therapeutic interventions. Due to the conserved reaction mechanism of catalysis, protein kinases seem well "drugable" by small molecular weight inhibitors, thus opening the chance to novel oral bioavailable drug development. A large number of small molecule weight inhibitors for protein kinases have already been introduced into research and these molecules are extensively analysed in regard to their efficiency, potency and selectivity. Here we summarise the use of small molecule protein kinase inhibitors relevant for acute and chronic inflammation based on their essential role in cellular signaling mechanisms in immune cells such as macrophages, lymphoytes and granulocytes. We describe the progress made to develop inhibitors against Toll-like receptor associated kinases (IRAKs), against the MAPK kinase kinases Cot/Tpl-2 and TAK1, against Inhibitor-kappaB kinases (IKKs), against MAPK kinases (MEKs, MKKs), against MAPKs (ERK2, p38, JNKs) and against their downstream kinases MNK1 and MK2/3. This overview should help to keep up with the fast developing field and the continuously growing number of protein kinase inhibitors.     

Molecular targets for the treatment of multiple myeloma

Multiple myeloma (MM) represents a suitable disease to be treated with Molecularly targeted drugs (MTDs). MM clone aberrations affect signal transduction pathways controlling both proliferation and/or cell survival. Research findings on small drugs or monoclonal antibodies (mAb) against the components of these pathways are now available and related clinical trials in MM patients are rapidly growing up. Promising results have been recently obtained with AKT inhibitors (perifosine) and mTOR inhibitors (everolimus and temsirolimus). However, the activity of these agents used alone is still limited and can be strongly increased by their combination with other drugs such as bortezomib or dexamethasone. The present review will summarize the main signaling components that can be targeted by MTDs and the most important available results derived from the clinical trials based on their use. Another important issue in the treatment of MM is the control of the related bone disease. Two main strategies can be used: i) inhibition of bone resorption and ii) promotion of bone formation. Emerging clinical data suggest that specific MTDs are able to prolong survival not only for the prevention of the skeletal-related events but also for a direct or indirect effect on the proliferation and/or survival of MM cells. A summary on the main preclinical and clinical results in this setting will be provided. In conclusion, the use of MTD in the treatment of MM is a promising approach but still far from becoming a current indication: a new dawn is arising with still unpredictable results.     

活性小分子化合物靶点验证方法的研究进展

随着科学的发展和时代的进步,药物化学的研究不仅仅局限于先导化合物的发现及其构效关系的研究,一些小分子药物靶点的确认正逐渐成为阻碍药物化学发展的瓶颈问题。因此,活性小分子化合物靶点的鉴定与确认也成为研究过程中最为关键和艰巨的任务,通常会起到决定性作用。本文简要总结活性小分子化合物靶点验证的现行方法,阐述通过合成探针进行靶标鉴别的手段,介绍探针的设计与合成思想,并列举应用这些方法成功找到靶点的实例。     

Caspases: recent advances in small molecule inhibitors

Caspases are a family of intracellular cysteine proteases that play critical roles in both cytokine maturation and apoptosis. Since this family of enzymes was discovered, there has been increasing interest in their pharmacological modulation, which may provide useful therapies for inflammatory diseases, such as rheumatoid arthritis, or in conditions where inappropriate apoptosis contributes to disease pathologies such as neurodegenerative disorders and ischaemia-related cell death. Thus, there is currently considerable activity in the search for caspase inhibitors. This review describes and summarises selected patent activity in this field from January 1998 to April 2001, with particular emphasis placed on those patents which disclose novel small molecule inhibitors of this important class of enzymes.     

ACK1小分子抑制剂的研究进展

ACK1/TNK2 (活化的Cdc42相关激酶)是一种非受体酪氨酸激酶,最初通过与GTP结合的小GTP酶Cdc42结合而被鉴定。它在人体中广泛表达,被EGF、PDGF、TGF-β等多种细胞外生长因子激活。激活的ACK1通过与下游效应子相互作用并使其磷酸化来介导信号级联反应。近年来对ACK1生物学功能及其参与癌症的研究多有报道,在肺癌、卵巢癌和前列腺癌等多种癌症中均发现ACK1的基因扩增和过表达,并与不良预后和转移表型相关,表明ACK1是癌症治疗的潜在靶点。因此,以ACK1为靶点研发高效选择性的小分子抑制剂可为癌症治疗提供潜在的候选药物。本综述简略描述了ACK1的激活方式以及在癌症中作用,介绍了靶向ACK1小分子抑制剂的最新研究进展,并展望和讨论了临床前研究中有应用前景的新型ACK1抑制剂。     

Synthetic small molecule Cdc25 phosphatases inhibitors

Inhibition of Cdc25 phosphatases is a strategy for the discovery and development of novel anticancer agents targeting the cell cycle. A number of potent small molecule Cdc25 inhibitors have been identified. They are derived from different chemical classes; the most potent and selective derivatives are quinones. The electrophilic properties of quinones suggest the possibility of inducing a sulphydryl arylation of a cysteine in the enzyme active site. It is also possible that inhibition is due to redox cycling activity and production of ROS. Thus, oxidation of the thiolate form of cysteine occurs, leading to inactivation of enzymatic activity. Many of these inhibitors are active on all three Cdc25 phosphatases, cause cell cycle arrest and inhibit the growth of several human tumor cell lines. The possibility of toxicities induced by ROS, prompted the search for non-quinoid antagonists. It is not yet clear how these compounds bind within the enzyme's active site. Generally, electrophilic moieties able to trap the catalytic cysteine play an important role. Another strategy for identifying Cdc25 inhibitors is the development of compounds able to interact with the conserved loop region instead of phosphate.. In this review a summary of the most interesting Cdc25 inhibitors is given together with their biological activity. SAR studies concerning the importance of some structural features will be described.     

激酶小分子抑制剂研究进展

蛋白激酶与肿瘤、炎症、自身免疫病、神经性疾病等众多疾病的发病机制密切相关,近30年以来激酶作为一个非常有潜力的药物靶点受到了广泛研究.截止2020年4月,FDA批准了59个激酶小分子抑制剂上市,再次激发了针对癌症和其他疾病治疗领域的靶向药物的兴起.本文重点分析了59个已获批上市的药物以及处于Ⅱ期和Ⅲ期临床试验的121个...     

Farnesyltransferase inhibitors and rapamycin in the treatment of multiple myeloma

Multiple myeloma (MM) is a B-cell malignancy characterized by an accumulation of long-lived neoplastic plasma cells (PC) within the bone marrow (BM). Novel treatments are not only targeting myeloma cells but also directly interfere with myeloma-stromal cell interactions, interrupting signal transduction pathways. Farnesyltransferase inhibitors (FTIs) and rapamycin represent novel classes of signal transduction inhibitors targeting principally Ras/MAPK and PI3K/Akt pathway. Pre-clinical and early clinical reports are presented in this study.     

小分子PIM激酶抑制剂的研究进展

PIM激酶家族在各类肿瘤中高表达,并对肿瘤的发生发展起着重要的调节作用,闪此PIM激酶有望成为抗癌药物的新靶点,小分子PIM激酶抑制剂具有良好的应用前景。本文从PIM激酶家族蛋门结构、在肿瘤发生发展中的作用途径以及小分子PIM激酶抑制剂的研究进展j个方面进行综述。     

肉毒神经毒素小分子抑制剂的研究进展

肉毒神经毒素(BoNT)是目前已知毒性最大的生物毒素,分为血清型A～G,具有高专一性地使表面神经末梢迟缓性麻痹的特点。由于BoNT具有简单易得和特殊的作用机制,近年来被广泛应用于美容和临床治疗及研究,存在由于过量使用引起中毒的风险。同时,由于其高毒性,BoNT也是潜在的恐怖分子比较青睐的生化武器。因此,对于BoNT抑制剂的研究刻不容缓。本文综述了BoNT的结构及其引起中毒的分子机制,重点综述了近年来靶向A型BoNT轻链锌活性位点的8-羟基喹啉类、异羟肟羧酸类小分子抑制剂、A型BoNT轻链共价结合的不可逆小分子抑制剂、靶向A型BoNT轻链外结合位点的小分子非竞争抑制剂,以及靶向B、E型BoNT轻链的小分子抑制剂等方面的研究进展。     

Proteasome inhibitors for the treatment of multiple myeloma

Introduction: Multiple Myeloma (MM) management is rapidly evolving, with a spectrum of novel treatments that have changed our approach to the therapy. Proteasome inhibitors (PIs) have revolutionized the scenario of both relapsed/refractory and newly diagnosed patients. The efficacy of bortezomib, the first PI approved, followed by carfilzomib and, the oral ixazomib, have been tested in several trials as single agents or in combination.

Areas covered: In this review, the authors summarize mechanism of action, efficacy and safety of proteasome inhibitors in MM and focus on data derived from clinical trials, analyzing adverse events and their relative management.

Expert opinion: The authors believe that, currently, the best course of action in the treatment of MM is to use PIs in combination with immunomodulatory drugs (IMiDs) and/or with monoclonal antibodies for all patients. However, based on the patient-specific characteristics, it is important to avoid inappropriate discontinuation by knowing the single side effects of every agent in order to balance their efficacy and safety.