Progress in the development of small molecular inhibitors of the Bruton's tyrosine kinase (BTK) as a promising cancer therapy.

Bruton tyrosine kinase (BTK) is a key kinase in the B cell antigen receptor signal transduction pathway, which is involved in the regulation of the proliferation, differentiation and apoptosis of B cells. BTK has become a significant target for the treatment of hematological malignancies and autoimmune diseases. Ibrutinib, the first-generation BTK inhibitor, has made a great contribution to the treatment of B cell malignant tumors, but there are still some problems such as resistance or miss target of site mutation. Therefore, there is an imperative need to develop novel BTK inhibitors to overcome these problems. Besides, proteolysis targeting chimera (PROTAC) technology has been successfully applied to the development of BTK degradation agents, which has opened a fresh way for the BTK targeted treatment. This paper reviews the biological function of BTK, the discovery and development of BTK targeted drugs as a promising cancer therapy. It mainly reviews the binding sites and structural characteristics of BTK, structure-activity relationships, activity and drug resistance of BTK inhibitors, as well as potential treatment strategies to overcome the resistance of BTK, which provides a reference for the rational design and development of new powerful BTK inhibitors.

Drug Discovery Targeting Focal Adhesion Kinase (FAK) as a Promising Cancer Therapy.

FAK is a nonreceptor intracellular tyrosine kinase which plays an important biological function. Many studies have found that FAK is overexpressed in many human cancer cell lines, which promotes tumor cell growth by controlling cell adhesion, migration, proliferation, and survival. Therefore, targeting FAK is considered to be a promising cancer therapy with small molecules. Many FAK inhibitors have been reported as anticancer agents with various mechanisms. Currently, six FAK inhibitors, including GSK-2256098 (Phase I), VS-6063 (Phase II), CEP-37440 (Phase I), VS-6062 (Phase I), VS-4718 (Phase I), and BI-853520 (Phase I) are undergoing clinical trials in different phases. Up to now, there have been many novel FAK inhibitors with anticancer activity reported by different research groups. In addition, FAK degraders have been successfully developed through "proteolysis targeting chimera" (PROTAC) technology, opening up a new way for FAK-targeted therapy. In this paper, the structure and biological function of FAK are reviewed, and we summarize the design, chemical types, and activity of FAK inhibitors according to the development of FAK drugs, which provided the reference for the discovery of new anticancer agents.

Discovery of Novel Diarylamide N-Containing Heterocyclic Derivatives as New Tubulin Polymerization Inhibitors with Anti-Cancer Activity.

Tubulin has been regarded as an attractive and successful molecular target in cancer therapy and drug discovery. Vicinal diaryl is a simple scaffold found in many colchicine site tubulin inhibitors, which is also an important pharmacophoric point of tubulin binding and anti-cancer activity. As the continuation of our research work on colchicine binding site tubulin inhibitors, we designed and synthesized a series of diarylamide N-containing heterocyclic derivatives by the combination of vicinal diaryl core and N-containing heterocyclic skeletons into one hybrid though proper linkers. Among of these compounds, compound 15b containing a 5-methoxyindole group exhibited the most potent inhibitory activity against the tested three human cancer cell lines (MGC-803, PC-3 and EC-109) with IC50 values of 1.56 µM, 3.56 µM and 14.5 µM, respectively. Besides, the SARs of these compounds were preliminarily studied and summarized. The most active compound 15b produced the inhibition of tubulin polymerization in a dose-dependent manner and caused microtubule network disruption in MGC-803 cells. Therefore, compound 15b was identified as a novel tubulin polymerization inhibitor targeting the colchicine binding site. In addition, the results of molecular docking also suggested compound 15b could tightly bind into the colchicine binding site of ß-tubulin.

Ras/Raf/MEK/ERK pathway axis mediated neurotoxicity induced by high-risk pesticide residue-Avermectin.

Pesticide residues have become a healthy threaten of human beings. Among the pesticides, many of them have neurotoxicity. Extracellular Regulated Protein Kinases (ERK) pathway is an important signaling pathway that regulates a variety of downstream progress. In this work, peach (PRUNUS persica) and cherry (PRUNUS cerasus) were sampled from over 300 plantations in China and assessed for the residue risk. In mechanism studies, high-risk pesticide Avermectin showed a high activity inhibiting three neurotoxicity models, SH-SY5Y, PC-12 and SK-N-SH cells. At protein levels, ERK pathway proteins and their downstream proteins were obviously down-regulated. Moreover, the effects of low-dose Avermectin can be accumulated at protein levels in the low-dose long-term chronic toxicology detection.

Synthesis and Biological Evaluation of Amino Chalcone Derivatives as Antiproliferative Agents.

Chalcone is a common scaffold found in many biologically active compounds. The chalcone scaffold was also frequently utilized to design novel anticancer agents with potent biological efficacy. Aiming to continue the research of effective chalcone derivatives to treat cancers with potent anticancer activity, fourteen amino chalcone derivatives were designed and synthesized. The antiproliferative activity of amino chalcone derivatives was studied in vitro and 5-Fu as a control group. Some of the compounds showed moderate to good activity against three human cancer cells (MGC-803, HCT-116 and MCF-7 cells) and compound 13e displayed the best antiproliferative activity against MGC-803 cells, HCT-116 cells and MCF-7 cells with IC50 values of 1.52 µM (MGC-803), 1.83 µM (HCT-116) and 2.54 µM (MCF-7), respectively which was more potent than the positive control (5-Fu). Further mechanism studies were explored. The results of cell colony formatting assay suggested compound 10e inhibited the colony formation of MGC-803 cells. DAPI fluorescent staining and flow cytometry assay showed compound 13e induced MGC-803 cells apoptosis. Western blotting experiment indicated compound 13e induced cell apoptosis via the extrinsic/intrinsic apoptosis pathway in MGC-803 cells. Therefore, compound 13e might be a valuable lead compound as antiproliferative agents and amino chalcone derivatives worth further effort to improve amino chalcone derivatives' potency.

Discovery of novel tertiary amide derivatives as NEDDylation pathway activators to inhibit the tumor progression in vitro and in vivo.

NEDDylation pathway regulates multiple physiological process, unlike inhibitors, NEDDylation activators are rarely studied. Novel amide derivatives were synthesized and evaluated for antiproliferative activity against MGC803, MCF-7 and PC-3 cells. Among them, Ⅶ-31 displayed the most potent activity with an IC50 value of 94 nmol/L against MGC803 cells. Cellular mechanisms elucidated that Ⅶ-31 inhibited the cell viability, arrested cell cycle at G2/M phase and induced apoptosis via intrinsic and extrinsic pathways against MGC803 cells. In addition, Ⅶ-31 activated NAE1-Ubc12-Cullin1 NEDDylation via interacting with NAE1 directly. Furthermore, the activation of NEDDylation resulted in the degradation of inhibitor of apoptosis proteins (IAPs). Importantly, Ⅶ-31 inhibited tumor growth in xenograft models in vivo without the apparent toxicity. In summary, it is the first time to reveal that Ⅶ-31 deserves consideration for cancer therapy as a NEDDylation activator.

[Host factor Moloney leukemia virus 10 (MOV10) protein inhibits replication of the xenotropic murine leukemia virus-related virus (XMRV)].

We investigated inhibition of Moloney leukemia virus 10 (MOV10) upon xenotropic murine leukemia virus-related virus (XMRV) and made a preliminary study of the mechanism of action. Using transfection, infection, western blotting and real-time polymerase chain reaction, we found that MOV10 inhibited XMRV replication. Using MOV10 overexpressed in viral producer cells, MOV10 was shown to reduce the infectivity of XMRV. MOV10 could be incorporated into XMRV, suggesting that MOV10 could undergo encapsidation by XMRV during viral assembly. MOV10 could also restrict the DNA production of XMRV in target cells. We found that the putative RNA-helicase domain of MOV10 maintained most of its XMRV inhibition. These results suggest that MOV10 could be required during the retroviral lifecycle. Perturbation of MOV10 disrupts the generation of infectious viral particles, suggesting that MOV10 has broad antiretroviral activity. Hence, MOV10 could be actively involved in host defense against retroviral infection.

[Establishment of a high-throughput screening assay for interaction inhibitor between BST-2 and Vpu].

BST-2 plays an important role in host innate immune response via inhibiting the release of HIV-1. HIV-1 accessory protein Vpu can interact with BST-2 through its transmembrane domains, degrade BST-2, and decrease BST-2 that are transported to the cell surface, thus anti-virus function of BST-2 is antagonized. In our study, we constructed plasmid RB connecting Rluc to the N-termimal of BST-2, and plasmid VE connecting EYFP to the C-terminal of Vpu. The two fusion proteins were co-expressed in 293 cells, and the interaction between the two proteins was detected via BRET method. And we further established a stable 293 cell line of dual-expression. By using BRET method, and the interaction between BST-2 and Vpu transmembrane domain as the target, a high-throughput screening assay was created that was expected to seek novel interaction inhibitors.

[Inhibition of HIV virus-like particles production by BST-2].

Recently, BST-2 has been identified as an effective cellular factor that prevents the release of human immunodeficiency virus type 1 and other enveloped viruses by tethering virus particles to the cell surface. Here, we showed that the production of HIV-1 virus-like particles was markedly inhibited by BST-2. Both the transient and stable expressing of BST-2 had the same function and Vpu rescued the release of HIV-1 VLP in the presence of human BST-2. Consistent with a direct tethering mechanism, we confirmed that proteolysis releases restricted virions and further showed that this removed the ectodomain of BST-2 from the cell surface.

[Synergic effects of Danggui Buxue Decoction in reducing toxicity of cytoxan in tumor-bearing mice].

OBJECTIVE: To study the inhibitory effect of Danggui Buxue Tang (DBT), a compound traditional Chinese herbal medicine for supplementing blood, on tumor growth in tumor-bearing mice after inoculation of EL-4 cells, and its immune mechanism as well as its synergic effect in reducing toxicity of cytoxan (CTX). METHODS: Experiment was carried out in tumor-bearing mice after inoculation of EL-4 cells. The mice were randomly divided into four groups after 7 days of the inoculation: untreated group, DBT-treated group [24 g/(kg x d)], CTX-treated group [7.5 mg/(kg x d)] and DBT plus CTX-treated group, with another ten normal mice as control. Inhibitory rate of tumor growth, survival time, immune function and variability of blood cells were measured in the mice during the experiment. RESULTS: After treatment of relevant interventions for 15 days, the tumor in the DBT-treated group, CTX-treated group and DBT plus CTX-treated group grew slower than the untreated group (P<0.05). Murine survival time in the DBT-treated group, CTX-treated group and DBT plus CTX-treated group was lengthened as compared with that in the untreated group (P<0.05). Compared with the untreated group, all kinds of immune indexes in the DBT-treated group and DBT plus CTX-treated group were significantly improved (P<0.05), while the immune indexes in the CTX-treated group were decreased (P<0.05). Compared with the CTX-treated group, all kinds of immune indexes in the DBT plus CTX-treated group were significantly improved (P<0.05). CONCLUSIONS: DBT can enhance the immune function in tumor-bearing mice and the inhibitory effect of DBT on tumor growth is related to the enhanced immune response. DBT can also increase the therapeutic effects and reduce the side effects of CTX.