ATP gatekeeper of Plasmodium protein kinase may provide the opportunity to develop selective antimalarial drugs with multiple targets

Malaria is one of the most devastating infectious diseases that caused millions of clinical cases annually despite decades of prevention efforts. Recent cases of Plasmodium falciparum resistance against the only remaining class of effective antimalarial(artemisinin) in South East Asia may soon pose a significant threat. Hence, the identification of new antimalarial compounds with a novel mode of action is necessary to curb this problem. Protein kinase has been implicated as a valid target for drug development in diseases such as cancer and diabetes in humans. A similar approach is now recognized for the treatment of protozoan-related disease including malaria. Few Plasmodium protein kinases that are not only crucial for their survival but also have unique structural features have been identified as a potential target for drug development. In this review, studies on antimalarial drug development exploiting the size of Plasmodium protein kinase ATP gatekeeper over the past 15 years are mainly discussed. The ATP-binding site of Plasmodium protein kinases such as Pf CDPK1, Pf CDPK4, Pf PKG, Pf PK7, and Pf PI4K showed great potential for selective and multi-target inhibitions owing to their smaller or unique ATP-gatekeeper amino acid subunits compared to that of human protein kinase. Hence it is a feasible solution to identify a new class of active antimalarial agents with a novel mode of action and longer clinical life-span.

ABNORMAL PROTEIN TYROSINE KINASES ASSOCIATED WITH HUMAN HAEMATOLOGICAL MALIGNANCIES

Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRβ fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.

Inhibition of RhoA/Rho-kinase pathway suppresses the expression of extracellular matrix induced by CTGF or TGF-β in ARPE-19

AIM:To investigate the role of Rho-associated protein kinase (ROCK) inhibitor, Y27632, in mediating the production of extracellular matrix (ECM) components including fibronectin, matrix metallo-proteinase-2 (MMP-2) and type I collagen as induced by connective tissue growth factor(CTGF) or transforming growth factor-β (TGF-β) in a human retinal pigment epithelial cell line, ARPE-19. METHODS:The effect of Y27632 on the CTGF or TGF-β induced phenotype in ARPE-19 cells was measured with immunocytochemistry as the change in F-actin. ARPE-19 cells were treated with CTGF (1, 10, 100ng/mL)and TGF-β (10ng/mL) in serum free media, and analyzed for fibronectin, laminin, and MMP-2 and type I collagen by RT-qPCR and immunocytochemistry. Cells were also pretreated with an ROCK inhibitor, Y27632, to analyze the signaling contributing to ECM production. ·RESULTS:Treatment of ARPE-19 cells in culture with TGF-β or CTGF induced an ECM change from a cobblestone morphology to a more elongated swirl pattern indicating a mesenchymal phenotype. RT-qPCR analysis and different gene expression analysis demonstrated an upregulation in expression of genes associated with cytoskeletal structure and motility. CTGFor TGF-β significantly increased expression of fibronectin mRNA (P =0.006, P =0.003 respectively), laminin mRNA (P =0.006, P =0.005), MMP-2 mRNA (P =0.006, P =0.001), COL1A1 mRNA (P =0.001, P =0.001), COL1A2 mRNA (P = 0.001, P =0.001). Preincubation of ARPE-19 with Y27632 (10mmol/L) significantly prevented CTGF or TGF-β induced fibronectin (P=0.005, P=0.003 respectively), MMP-2 (P = 0.003, P =0.002), COL1A1 (P =0.006, P =0.003), and COL1A2 (P =0.006, P =0.004) gene expression, but not laminin (P =0.375, P =0.516). CONCLUSION:Our study demonstrated that both TGF-β and CTGF upregulate the expression of ECM components including fibronectin, laminin, MMP-2 and type I collagen by activating the RhoA/ROCK signaling pathway. During this process, ARPE-19 cells were shown to change from an epithelial to a mesenchymal phenotype in vitro. Y27632, a ROCK inhibitor, inhibited the transcription of fibronectin, MMP-2 and type I collagen, but not laminin. The data from our work suggest a role for CTGF as a profibrotic mediator. Inhibiting the RhoA/ROCK pathway represents a potential target to prevent the fibrosis of retinal pigment epithelial (RPE) cells. This might lead to a novel therapeutic approach to preventing the onset of early proliferative vitreoretinopathy(PVR).

Abemaciclib, a Recent Novel FDA-Approved Small Molecule Inhibiting Cyclin-Dependant Kinase 4/6 for the Treatment of Metastatic Breast Cancer: A Mini-Review

Abemaciclib (Verzerio®) is a cell cycle inhibitor of both CDK4 and CDK6. In 2017, abemaciclib was approved by the Food and Drug Administration (FDA) and, in 2018 by the European Medicines Agency (EMA) for the treatment of postmenopausal women with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2−) advanced breast cancer. In this mini-review, we provide a series of information for respectively their targets and its selectivity, results on preclinical trial, clinical phase I, II and III trials, and some perspectives. We also describe the batch and flow steps used for the synthesis of this cancer drug.

Sunitinib-induced hyperammonemic encephalopathy in metastatic gastrointestinal stromal tumors:A case report

BACKGROUND Sunitinib,a multi-targeted tyrosine kinase inhibitor(TKI),has been approved for the salvage treatment of gastrointestinal stromal tumors(GIST).Hyperammonemic encephalopathy is a rare but severe complication of sunitinib use.Here,we present the case of a 66-year-old male with metastatic GIST without underlying liver cirrhosis who developed sunitinib-induced hyperammonemic encephalopathy.CASE SUMMARY A 66-year-old male with metastatic GIST was admitted because of reduced consciousness.Imatinib was administered as the first-line systemic therapy.He experienced repeated episodes of peritonitis due to tumor perforation,and surgery was performed.Progressive disease was confirmed based on increased liver metastasis,and sunitinib was initiated as a salvage treatment.However,23 d after the third course of sunitinib,he presented to the emergency room with an episode of altered consciousness and behavioral changes.Based on the patient clinical history and examination findings,sunitinib-induced encephalopathy was suspected.Sunitinib was discontinued,and the patient was treated for hyperammonemia.The patient had a normal level of consciousness four days later,and the serum ammonia level gradually decreased.No further neurological symptoms were reported in subsequent follow-ups.CONCLUSION TKI-induced hyperammonemic encephalopathy is potentially life-threatening.Patients receiving TKIs experiencing adverse reactions should undergo systemic evaluation and prompt treatment.

Effects of U0126 on growth and activation of mitogen-activated protein kinases in Aspergillus fumigatus

Background Invasive aspergillosis （IA）, which is mainly caused by Aspergillus fumigatus （A. fumigatus）, is a major cause of morbidity and mortality in immunocompromised patients. Despite considerable progress in currently available antifungals the mortality still remains high in critically ill patients. U0126 which is a highly selective inhibitor of MEK1 and MEK2 in the RAF/MEK/ERK pathway in mammalian cells has been demonstrated to have an anti-proliferative role in cancer cells. The purpose of this study was to explore the role of U0126 on growth inhibition and activation of mitogen-activated protein kinases （MAPKs） in A. fumigatus. Methods Germination percentage and hyphae growth in A. fumigatus treated with U0126 were observed and compared with untreated controls. Western blotting analysis was used to detect changes in activation of SakA, MpkA and MpkB. Results U0126 inhibited germination and hyphae growth in A. fumigatus and enhanced the phosphorylation of SakA and MpkA under oxidative stress. U0126 at 10 pmol/L did not block the activation of MpkB during nitrogen starvation stress. Conclusion U0126 shows promise as an antifungal candidate and the MAPK pathway may be a possible antifungal drug target for A. fumigatus.

Lenvatinib-induced multiorgan adverse events in Hurthle cell thyroid cancer: A case report

BACKGROUND The management of metastatic progressive radioiodine-resistant differentiated thyroid cancer remains challenging for clinicians.The availability of tyrosine kinase inhibitors(TKIs),sorafenib and lenvatinib,within the last decade has expanded treatment options;however,these lead to significant adverse effects,which may curtail their use.CASE SUMMARY We report the case of a 47-year-old female with Hurthle cell thyroid cancer who underwent total thyroidectomy followed by radioiodine ablation.During followup,she developed noniodine-avid renal and pulmonary metastases.With respect to her pre-existing diabetes,hypertension,and polycystic kidney disease,the tumor board decided against performing renal metastasectomy because of the risk of future renal decline requiring dialysis.Metastases were treated using sorafenib,which provided stability followed by progression within a year.We switched to lenvatinib,which led to disease regression.However,the patient experienced severe adverse effects,including cardiomyopathy,bicytopenia,renal impairment,and the rarely reported nephrotic syndrome.Renal metastasis is a rare manifestation of Hurthle cell thyroid cancer with only two reported cases in literature.We report the experience of our first case of renal metastasis and its treatment with TKIs.This case serves as a reminder of the adverse drug reactions associated with TKI use.CONCLUSION We advocate close monitoring of patients’hematological and renal profiles as well as their cardiac status using an echocardiogram.

Immunotherapy in hepatocellular carcinoma: Combination strategies

Liver cancer is one of the most common causes of cancer death globally,and its incidence in the United States is increasing.Patients with advanced hepatocellular carcinoma(HCC)who are not candidates for surgical resection,liver transplant,or locoregional therapies can be treated with systemic therapies.Multiple agents,including sorafenib,lenvatinib,and regorafenib are approved for use as either first-or second-line therapy in this patient population,but all have relatively modest survival benefits.HCC is potentially susceptible to therapy with checkpoint inhibitors,including agents such as nivolumab and pembrolizumab,which are both approved by the Food and Drug Administration for patients previously treated with sorafenib but have not demonstrated superior overall survival in phase III trials.It is clear that more effective approaches are needed to potentiate the effects of checkpoint inhibitors in patients with HCC.This review will outline and appraise the current literature on the use of checkpoint inhibitors in HCC as part of a combination treatment involving an additional mode of therapy.The list of agents that can be paired with checkpoint inhibitors includes an additional checkpoint inhibitor,vascular endothelial growth factor or vascular endothelial growth factor receptor inhibitors,tyrosine kinase inhibitors,OX-40 agonists,and PT-112 inhibitors.The main non-pharmacologic therapies currently being studied for inclusion in a combination strategy include radiation therapy,trans-arterial chemoembolization,and ablation.

RET kinase alterations in targeted cancer therapy

The rearranged during transfection(RET)gene encodes a protein tyrosine kinase.RET alterations by point mutations and gene fusions were found in diverse cancers.RET fusions allow abnormal expression and activation of the oncogenic kinase,whereas only a few of RET point mutations found in human cancers are known oncogenic drivers.Earlier studies of RET-targeted therapy utilized multi-targeted protein tyrosine kinase inhibitors(TKIs)with RET inhibitor activity.These multi-targeted TKIs often led to high-grade adverse events and were subject to resistance caused by the gatekeeper mutations.Recently,two potent and selective RET TKIs,pralsetinib(BLU-667)and selpercatinib(LOXO-292),were developed.High response rates to these selective RET inhibitors across multiple forms of RET alterations in different types of cancers were observed in clinical trials,demonstrating the RET dependence in human cancers harboring these RET lesions.Pralsetinib and selpercatinib were effective in inhibiting RETV804L/M gatekeeper mutants.However,adaptive mutations that cause resistance to pralsetinib or selpercatinib at the solvent front RETG810 residue have been found,pointing to the need for the development of the next-generation of RET TKIs.

Update on treatments of diabetic macular edema

Objective To review the update research progress about the treatment of diabetic macular edema and to give helpful guidelines in the treatment of diabetic macular edema based on available evidence to date. Data sources A literature search of all English articles was performed on the online electronic PubMed database dated 1984 to 2009. The keywords searched included： macular edema, therapy, laser coagulation, intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitor, protein kinase C inhibitor and Pars plana vitrectomy. After finding relevant articles within these search limits, a manual search was conducted through the references from these articles. Study selection Original articles and critical reviews were reviewed and selected to address the stated purpose. Results To date, demonstrated means to reduce the risk of vision loss from diabetic macular edema include focal/grid laser photocoagulation and improved metabolic control. Emerging pharmacologic therapies （intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitors and protein kinase C beta-isoform inhibitors） and Pars plana vitrectomy have shown early promise in the treatment of diabetic macular edema. Conclusions As there has been extensive development in multiple treatments of diabetic macular edema, choice of the most suitable treatment for specific patients becomes important. Combination therapy of laser, pharmacological and surqical treatment modalities mav offer an alternative to treatment of diabetic macular edema.

The inhibitor effect of RKIP on inflammasome activation and inflammasome-dependent diseases

Aberrant inflammasome activation contributes to the pathogenesis of various human diseases,including atherosclerosis,gout,and metabolic disorders.Elucidation of the underlying mechanism involved in the negative regulation of the inflammasome is important for developing new therapeutic targets for these diseases.Here,we showed that Raf kinase inhibitor protein(RKIP)negatively regulates the activation of the NLRP1,NLRP3,and NLRC4 inflammasomes.RKIP deficiency enhanced caspase-1 activation and IL-1P secretion via NLRP1,NLRP3,and NLRC4 Inflammasome activation In primary macrophages.The overexpression of RKIP in THP-1 cells inhibited NLRP1,NLRP3,and NLRC4 inflammasome activation.RKIP-deficient mice showed increased sensitivity to Aluminduced peritonitis and Salmonella typhimurium-induced inflammation,indicating that RKIP inhibits NLRP3 and NLRC4 inflammasome activation in vivo.Mechanistically,RKIP directly binds to apoptosis-associated speck-like protein containing a caspase-recruitment domain(ASC)and competes with NLRP1,NLRP3,or NLRC4 to interact with ASC thus interrupting inflammasome assembly and activation.The depletion of RKIP aggravated inflammasome-related diseases such as monosodium urate(MSU)-induced gouty arthritis and high-fat diet(HFD)-induced metabolic disorders.Furthermore,the expression of RKIP was substantially downregulated in patients with gouty arthritis or type 2 diabetes(T2D)compared to healthy controls.Collectively,our findings suggest that RKIP negatively regulates NLRP1,NLRP3,and NLRC4 inflammasome activation and is a potential therapeutic target for the treatment of inflammasome-related diseases.

Growth factor receptors: promising drug targets in cancer

Genetic,epigenetic and somatic changes deregulate the expression of growth factor receptors(GFRs),leading to cancer initiation and progression.Tumor cell growth and survival are orchestrated by clonal expansion and evasion of apoptotic signals in cancer cells.The growth of cells is further supported by angiogenesis and metastasis to distant organs.High expression of GFRs also contributes to the development of resistance.Therefore,therapeutics to target GFRs is a potentially attractive molecular approach to treat cancer more effectively.In this review,we have discussed the contribution of GFRs to cancer development and addressed molecular approaches undertaken to inhibit GFR-mediated pathways.A wide number of monoclonal antibodies(mAbs)and protein kinase inhibitors targeting these GFR-mediated functions are in clinical trials to treat human malignancies.However,most drugs that target GFRs lead to the development of drug resistance and generate adverse effects.Nucleic acid-based therapeutics,e.g.short interfering RNA(siRNA)could be harnessed to selectively silence GFR genes in cancer cells.Different polymer,liposome-based nanocarriers,and the most recently developed pH-sensitive inorganic carbonate apatite nanoparticles have been used in cell culture and preclinical trials for cytoplasmic delivery of the siRNAs targeting different GFR genes.siRNA-based therapeutics have been shown to have signifi cant potential to suppress GFR expression and functions and thus could be developed as molecular therapeutics.Multi-targeting of tumors at different levels by combining various approaches along with chemotherapy would be a promising therapeutic approach to fight the disease.Suitable nanocarriers capable of entrapping siRNA,mAb,GFR inhibitors and classical drugs targeting GFR have potential therapeutic applications.

Urothelial bladder cancer progression: lessons learned from the bench

Urothelial bladder carcinoma(UBC)is an intricate malignancy with a variable natural history and clinical behavior.Despite developments in diagnosis/prognosis refi nement and treatment modalities,the recurrence rate is high,and progression from non-muscle to muscle invasive UBC commonly leads to metastasis.Moreover,patients with muscle-invasive or extra-vesical disease often fail the standard chemotherapy treatment,and overall survival rates are poor.Thus,UBC remains a challenge in the oncology fi eld,representing an ideal candidate for research on biomarkers that could identify patients at increased risk of recurrence,progression,and chemo-refractoriness.However,progress toward personalized medicine has been hampered by the unique genetic complexity of UBC.Recent genome-wide expression and sequencing studies have brought new insights into its molecular features,pathogenesis and clinical diversity,revealing a landscape where classical pathology is intersected by the novel and heterogeneous molecular groups.Hence,it seems plausible to postulate that only an integrated signature of prognostic/predictive biomarkers inherent in different cancer hallmarks will reach clinical validation.In this review,we have summarized ours and others’research into novel putative biomarkers of progression and chemoresistance that encompass several hallmarks of cancer:tumor neovascularization,invasion and metastasis,and energy metabolism reprogramming of the tumor microenvironment.