c-Src Kinase Research Articles

The Relevance of the SH2 Domain for c-Src Functionality in Triple-Negative Breast Cancer Cells.

Simple SummaryTriple-Negative breast cancers (TNBC) have not specific therapeutic targets and are considered the most aggressive mammary tumors. c-Src controls several cellular processes: proliferation, differentiation, survival, motility, and angiogenesis. Alteration of c-Src functionality, by increasing its expression and/or its kinase activity, is associated to progression and metastasis of tumors in mammary gland, pancreas, colon, brain, and lung. However, c-Src tyrosine kinase inhibitors alone are not fully clinically effective, suggesting that c-Src adapter SH2/SH3 domains may be important. We questioned whether the SH2-c-Src domain is relevant for tumorigenicity of TNBC SUM159 and MDA-MB-231 human cell lines. Conditional expression of SH2 and SH3 inactivating mutants in these TNBC cells, or transfection of aptamers directed to SH2, allowed us to show that this domain is required for their tumorigenesis. Therefore, the SH2-c-Src domain could be a promising therapeutic target that, combined with c-Src kinase inhibitors, may represent a novel therapeutic strategy for TNBC patients.The role of Src family kinases (SFKs) in human tumors has been always associated with tyrosine kinase activity and much less attention has been given to the SH2 and SH3 adapter domains. Here, we studied the role of the c-Src-SH2 domain in triple-negative breast cancer (TNBC). To this end, SUM159PT and MDA-MB-231 human cell lines were employed as model systems. These cells conditionally expressed, under tetracycline control (Tet-On system), a c-Src variant with point-inactivating mutation of the SH2 adapter domain (R175L). The expression of this mutant reduced the self-renewal capability of the enriched population of breast cancer stem cells (BCSCs), demonstrating the importance of the SH2 adapter domain of c-Src in the mammary gland carcinogenesis. In addition, the analysis of anchorage-independent growth, proliferation, migration, and invasiveness, all processes associated with tumorigenesis, showed that the SH2 domain of c-Src plays a very relevant role in their regulation. Furthermore, the transfection of two different aptamers directed to SH2-c-Src in both SUM159PT and MDA-MB-231 cells induced inhibition of their proliferation, migration, and invasiveness, strengthening the hypothesis that this domain is highly involved in TNBC tumorigenesis. Therefore, the SH2 domain of c-Src could be a promising therapeutic target and combined treatments with inhibitors of c-Src kinase enzymatic activity may represent a new therapeutic strategy for patients with TNBC, whose prognosis is currently very negative.

Epidermal growth factor receptor activity upregulates lactate dehydrogenase A expression, lactate dehydrogenase activity, and lactate secretion in cultured IB3-1 cystic fibrosis lung epithelial cells.

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. It has been postulated that reduced HCO3- transport through CFTR may lead to a decreased airway surface liquid pH. In contrast, others have reported no changes in the extracellular pH (pHe). We have recently reported that in carcinoma Caco-2/pRS26 cells (transfected with short hairpin RNA for CFTR) or CF lung epithelial IB3-1 cells, the mutation in CFTR decreased mitochondrial complex I activity and increased lactic acid production, owing to an autocrine IL-1β loop. The secreted lactate accounted for the reduced pHe, because oxamate fully restored the pHe. These effects were attributed to the IL-1β autocrine loop and the downstream signaling kinases c-Src and JNK. Here we show that the pHe of IB3-1 cells can be restored to normal values (∼7.4) by incubation with the epidermal growth factor receptor (EGFR, HER1, ErbB1) inhibitors AG1478 and PD168393. PD168393 fully restored the pHe values of IB3-1 cells, suggesting that the reduced pHe is mainly due to increased EGFR activity and lactate. Also, in IB3-1 cells, lactate dehydrogenase A mRNA, protein expression, and activity are downregulated when EGFR is inhibited. Thus, a constitutive EGFR activation seems to be responsible for the reduced pHe in IB3-1 cells.

Characterization of the interactome of c-Src within the mitochondrial matrix by proximity-dependent biotin identification

C-Src kinase is localized in several subcellular compartments, including mitochondria where it is involved in the regulation of organelle functions and overall metabolism. Surprisingly, the characterization of the intramitochondrial Src interactome has never been fully determined. Using in vitro proximity-dependent biotin identification (BioID) coupled to mass spectrometry, we identified 51 candidate proteins that may interact directly or indirectly with c-Src within the mitochondrial matrix. Pathway analysis suggests that these proteins are involved in a large array of mitochondrial functions such as protein folding and import, mitochondrial organization and transport, oxidative phosphorylation, tricarboxylic acid cycle and metabolism of amino and fatty acids. Among these proteins, we identified 24 tyrosine phosphorylation sites in 17 mitochondrial proteins (AKAP1, VDAC1, VDAC2, VDAC3, LonP1, Hsp90, SLP2, PHB2, MIC60, UBA1, EF-Tu, LRPPRC, ACO2, OAT, ACAT1, ETFβ and ATP5β) as potential substrates for intramitochondrial Src using in silico prediction of tyrosine phospho-sites. Interaction of c-Src with SLP2 and ATP5β was confirmed using coimmunoprecipitation. This study suggests that the intramitochondrial Src could target several proteins and regulate different mitochondrial functions.

Capsaicin-loaded solid lipid nanoparticles: design, biodistribution, in silico modeling and in vitro cytotoxicity evaluation

Lower doses of capsaicin (8-methyl-N-vanillyl-6-nonenamide) have the potential to serve as an anticancer drug, however, due to its pungency, irritant effect, poor water solubility and high distribution volume often linked to various off-target effects, its therapeutic use is limited. This study aimed to determine the biodistribution and anticancer efficacy of capsaicin loaded solid lipid nanoparticles (SLNs) in human hepatocellular carcinoma in vitro. In this study, SLNs of stearic acid loaded with capsaicin was formulated by the solvent evaporation-emulsification technique and were instantly characterized for their encapsulation efficiency, morphology, loading capacity, stability, particle size, charge and in vitro drug release profile. Synthesized SLNs were predominantly spherical, 80 nm diameter particles that proved to be biocompatible with good stability in aqueous conditions. In vivo biodistribution studies of the formulated SLNs showed that 48 h after injection in the lateral tail vein, up to 15% of the cells in the liver, 1.04% of the cells in the spleen, 3.05% of the cells in the kidneys, 3.76% of the cells in the heart, 1.31% of the cells in the lungs and 0% of the cells in the brain of rats were determined. Molecular docking studies against the identified targets in HepG2 cells showed that the capsaicin is able to bind Abelson tyrosine-protein kinase, c-Src kinase, p38 MAP kinase and VEGF-receptor. Molecular dynamic simulation showed that capsaicin-VEGF receptor complex is highly stable at 50 nano seconds. The IC50 of capsaicin loaded SLNs in HepG2 cells in vitro was 21.36 μg × ml−1. These findings suggest that capsaicin loaded SLNs are stable in circulation for a period up to 3 d, providing a controlled release of loaded capsaicin and enhanced anticancer activity.

CSIG-07. c-Src PHOSPHORYLATES AND INACTIVATES THE CIC TUMOR SUPPRESSOR PROTEIN IN GLIOBLASTOMA

Abstract Capicua (CIC) is a transcriptional repressor that counteracts activation of genes in response to receptor tyrosine kinase (RTK)/Ras/MEK/ERK signaling. Following activation of RTK, ERK enters the nucleus and serine-phosphorylates CIC, releasing it from its targets to permit gene expression. We recently showed that ERK triggers ubiquitin-mediated degradation of CIC in glioblastoma (GBM). In this study, we examined whether another important downstream effector of RTK/EGFR, the non-receptor tyrosine kinase c-Src, affects CIC repressor function in GBM. We found that c-Src binds and tyrosine phosphorylates CIC on residue 1455 to promote nuclear export of CIC. On the other hand, CIC mutant allele (CIC-Y1455F), that escapes c-Src-mediated tyrosine phosphorylation, remains localized to the nucleus and retains strong repressor function against CIC targets, the oncogenic ETV transcription factors. Furthermore, we show that the orally available Src family kinase inhibitor, dasatinib, which prevents EGF-mediated tyrosine phosphorylation of CIC and attenuates elevated ETV levels, reduces viability of GBM cells and glioma stem cells (GSC), but not of their control cells with undetectable c-Src activity. In fact, GBM cells and GSC expressing the tyrosine-defective CIC mutant (Y1455F) lose sensitivity to dasatinib, further endorsing the effect of dasatinib on Src-mediated tyrosine phosphorylation of CIC. Importantly we show that combined inhibition of Src and MEK/ERK results in greatest stabilization of CIC and attenuation of proliferation compared to either inhibitor alone. These findings elucidate important mechanisms of CIC regulation and provide the rationale to target c-Src alongside ERK pathway inhibitors as a way to fully restore CIC tumor suppressor function in neoplasms such as GBM.

GO Nanosheets: Promising Nano Carrier for the S29, 1-(2-Chloro-2-(4-chlorophenyl-ethyl)-N-(4-fluorobenzyl)-1H-pyrazolo[3,4-d] pyrimidin-4-amine, Therapeutic Agent in Neuroblastoma

Graphene oxide (GO) derivatives are reported as a valid alternative to conventional carriers of therapeutic agents, because they have a large surface area, an excellent electrical and thermal conductivity and a great capacity for selective binding of drugs and therapeutics, due to the functionalization of their surfaces, edges and sides. In this work GO nanosheets, synthesized by electrochemical exfoliation of graphite (patent N 102015000023739, Tor Vergata University), were investigated as possible carriers of an anticancer drug, the S29, an inhibitor of a cytoplasmic tyrosine kinase (c-SRC) on a neuroblastoma cell line (SK N BE 2 cells). Neuroblastoma is a heterogenous tumor whose characteristics range from spontaneous regression to aggressive phenotypes that are due to different mutations that often occur in SRC family kinases. Inhibitors of tyrosine kinases are currently investigated for their anti-tumoral effects on aggressive neuroblastomas, but their uptake in cells and pharmacokinetics needs to be improved. In this work S29 was stably conjugated with highly water-dispersible GO nanoparticles. S29/GO complex formation was induced by 1h sonication and its stability was analyzed by chromatography coupled with spectrophotometry and mass spectrometry. The synthesized composite (GO-S29) was delivered into SK N BE 2 cells and its effects on cell viability, production of reactive oxygen species (ROS) and migration were studied. The results show that the compound GO-S29 exerts anti-tumoral effects on the neuroblastoma cell line, higher than both GO and S29 do alone and that GO has an additive effect on S29.

Gb3-cSrc complex in glycosphingolipid-enriched microdomains contributes to the expression of p53 mutant protein and cancer drug resistance via β-catenin-activated RNA methylation.

Glucosylceramide synthase (GCS) is a key enzyme catalyzing ceramide glycosylation to generate glucosylceramide (GlcCer), which in turn serves as the precursor for cells to produce glycosphingolipids (GSLs). In cell membranes, GSLs serve as essential components of GSL‐enriched microdomains (GEMs) and mediate membrane functions and cell behaviors. Previous studies showed that ceramide glycosylation correlates with upregulated expression of p53 hotspot mutant R273H and cancer drug resistance. Yet, the underlying mechanisms remain elusive. We report herewith that globotriaosylceramide (Gb3) is associated with cSrc kinase in GEMs and plays a crucial role in modulating expression of p53 R273H mutant and drug resistance. Colon cancer cell lines, either WiDr homozygous for missense‐mutated TP53 (R273H+/+) or SW48/TP53‐Dox bearing heterozygous TP53 mutant (R273H/+), display drug resistance with increased ceramide glycosylation. Inhibition of GCS with Genz‐161 (GENZ 667161) resensitized cells to apoptosis in these p53 mutant‐carrying cancer cells. Genz‐161 effectively inhibited GCS activity, and substantially suppressed the elevated Gb3 levels seen in GEMs of p53‐mutant cells exposed to doxorubicin. Complex formation between Gb3 and cSrc in GEMs to activate β‐catenin was detected in both cultured cells and xenograft tumors. Suppression of ceramide glycosylation significantly decreased Gb3‐cSrc in GEMs, β‐catenin, and methyltransferase‐like 3 for m6A RNA methylation, thus altering pre‐mRNA splicing, resulting in upregulated expression of wild‐type p53 protein, but not mutants, in cells carrying p53 R273H. Altogether, increased Gb3‐cSrc complex in GEMs of membranes in response to anticancer drug induced cell stress promotes expression of p53 mutant proteins and accordant cancer drug resistance.

A boosted unbiased molecular dynamics method for predicting ligands binding mechanisms: probing the binding pathway of dasatinib to Src-kinase.

Small molecules such as metabolites and drugs play essential roles in biological processes and pharmaceutical industry. Knowing their interactions with biomacromolecular targets demands a deep understanding of binding mechanisms. Dozens of papers have suggested that discovering of the binding event by means of conventional unbiased molecular dynamics (MD) simulation urges considerable amount of computational resources, therefore, only one who holds a cluster or a supercomputer can afford such extensive simulations. Thus, many researchers who do not own such resources are reluctant to take the benefits of running unbiased MD simulation, in full atomistic details, when studying a ligand binding pathway. Many researchers are impelled to be content with biased MD simulations which seek its validation due to its intrinsic preconceived framework. In this work, we have presented a workable stratagem to encourage everyone to perform unbiased (unguided) MD simulations, in this case a protein-ligand binding process, by typical desktop computers and so achieve valuable results in nanosecond time scale. Here, we have described a dynamical binding's process of an anticancer drug, the dasatinib, to the c-Src kinase in full atomistic details for the first time, without applying any biasing force or potential which may lead the drug to artificial interactions with the protein. We have attained multiple independent binding events which occurred in the nanosecond time scales, surprisingly as little as ∼30 ns. Both the protonated and deprotonated forms of the dasatinib reached the crystallographic binding mode without having any major intermediate state during induction. The links of the tutorial and technical documents are accessible in the article. Supplementary data are available at Bioinformatics online.

Abstract MP48: EGF Regulates VSMC Migration And Proliferation Through Crosstalk Between TRPM7 And EGFR

Epidermal growth factor (EGF), signals throught the EGF receptor (EGFR) and plays an important role in the pathogenesis of vascular remodeling. Transient receptor potential melastatin 7 (TRPM7) is a channel bound to a kinase domain important for Mg 2+ , Zn 2+ and Ca 2+ homeostasis. Cancer patients treated with EGFR inhibitors develop hypomagnesemia, suggesting a relationship between EGFR and TRPM7. Here we investigated the role of TRPM7 in EGF signaling in vascular smooth muscle cell (VSMC) from humans (hVSMC) and rats (rVSMC). VSMCs were stimulated with EGF (50ng/ml) for 5min and 24h with/without pretreatment of gefitinib (1μM), PP2 (10μM), 2APB (30μM) and NS8593 (40μM), inhibitors of EGFR, c-Src kinase and TRPM7 respectively. Aortas were isolated from wild type (WT), TRPM7-deficient (TRPM7 +/Δkinase ) and kinase-dead (TRPM7 R/R ) mice. Protein expression was assessed by immunoblotting. Ca 2+ and Mg 2+ were assessed using Cal-520 and Mg-green probes respectively. EGFR/TRPM7 interaction was investigated by proximity ligation assay (PLA), immunoprecipitation and confocal microscopy. VSMC migration and proliferation were examined by wound healing and CFSE proliferation assays. In hVSMC and rVSMC, EGF increased TRPM7 expression (47%) and phosphorylation (21%), (p<0.05); effects abolished by gefitinib and PP2. EGF-induced Mg 2+ and Ca 2+ influx was attenuated by gefitinib (4% and 8% respectively), NS8593 (5% for Mg 2+ ) and 2-APB (6% and 13% respectively). EGF enhanced ERK1/2 phosphorylation (3-fold) through c-Src, EGFR and TRPM7, p<0.05. Cell migration (26%) and proliferation (17%) were enhanced by EGF, and reduced by inhibitors of EGFR, TRPM7 and ERK1/2, p<0.05. EGF induced TRPM7-EGFR interaction (51%), which was reduced by gefitinib (34%) and PP2 (25%). VSMC from TRPM7 +/Δkinase showed reduced EGFR expression (73%), phospho-c-Src (22%), and phospho-ERK1/2 (90%). Aortas from TRPM7 R/R exhibited reduced phospho-EGFR (63%) and phospho-ERK1/2 (36%). Vessels from TRPM7 +/Δkinase showed reduced wall thickness (35%). Our findings demonstrate that interaction between EGFR/TRPM7 is a key process underlying EGF-induced VSMC migration and growth. This novel EGF-c-Src-EGFR-TRPM7 pathway may play an important role in vascular remodeling.

Calreticulin regulates Src kinase in osteogenic differentiation from embryonic stem cells.

Calreticulin, the major Ca2+ buffer of the endoplasmic reticulum plays an important role in the choice of fate by embryonic stem cells. Using the embryoid body method of organogenesis, we showed impaired osteogenesis in crt-/- cells vis-à-vis calreticulin-containing osteogenic WT cells. In the non-osteogenic crt-/- cells, c-Src- a non-receptor tyrosine kinase- was activated and its inhibition rescued osteogenesis. Most importantly, we demonstrated that calreticulin-containing cells had lower c-Src kinase activity, and this was accomplished via the Ca2+-homeostatic function of calreticulin. Specifically, lowering cytosolic [Ca2+] in calreticulin-containing osteogenic WT cells with BAPTA-AM, activated c-Src and impaired osteogenic differentiation. Conversely, increasing cytosolic [Ca2+] in crt-/- cells with ionomycin deactivated c-Src kinase and restored osteogenesis. The immediate effector of calreticulin, the Ser/Thr phosphatase calcineurin, was less active in crt-/- cells, however, its activity was rescued upon inhibition of c-Src activity by small molecule inhibitors. Finally, we showed that higher activity of calcineurin correlated with increased level of nuclear Runx2, a transcription factor that is the master regulator of osteogenesis. Collectively, our work has identified a novel pathway involving calreticulin regulated Ca2+ signalling via c-Src in osteogenic differentiation of embryonic stem cells.

Three-Dimensional Interactions Analysis of the Anticancer Target c-Src Kinase with Its Inhibitors.

Src family kinases (SFKs) constitute the biggest family of non-receptor tyrosine kinases considered as therapeutic targets for cancer therapy. An aberrant expression and/or activation of the proto-oncogene c-Src kinase, which is the oldest and most studied member of the family, has long been demonstrated to play a major role in the development, growth, progression and metastasis of numerous human cancers, including colon, breast, gastric, pancreatic, lung and brain carcinomas. For these reasons, the pharmacological inhibition of c-Src activity represents an effective anticancer strategy and a few compounds targeting c-Src, together with other kinases, have been approved as drugs for cancer therapy, while others are currently undergoing preclinical studies. Nevertheless, the development of potent and selective inhibitors of c-Src aimed at properly exploiting this biological target for the treatment of cancer still represents a growing field of study. In this review, the co-crystal structures of c-Src kinase in complex with inhibitors discovered in the past two decades have been described, highlighting the key ligand–protein interactions necessary to obtain high potency and the features to be exploited for addressing selectivity and drug resistance issues, thus providing useful information for the design of new and potent c-Src kinase inhibitors.

Synthesis And Characterization Of Novel Pyrimidine-4,5-Diamine As Anticancer Agent

Unlike latent cells, cancer cells supply deoxyribonucleoside triphosphates to cells continuously and thereby, prop up the uncontrolled cancer growth. Pyrimidine has been concerned in the separation of leukemic cells, known as adenine bioisosteres, as well as its biological activities, especially its anticancer properties. In this context, a novel series of N5-(3-substituted benzylidene)-N4-phenyl pyrimidine-4,5-diamine [5A-5F] / N5-(2-substituted benzylidene)-N2,N2-dimethyl-N4-phenyl pyrimidine-2,4,5-triamine [5a-5f] were synthesized by using the starting ingredient formimidamide/4-(dimethylamino) benzimidamide and sodium ethoxide. The synthesized compounds were characterized by IR, 1H NMR, and Mass spectral analyses and screened for their biological studies. In the present study, pyrimidine derivatives and their insilico modeling were done by using c-Src kinase and p38 MAP kinase complex followed by the evaluation of their anticancer activity. The screening of synthesized scaffolds possessed significant activity against HeLa cell lines and showed similar activity compared to standard Cisplatin. Among all the synthesized compounds, N5-(4-hydroxybenzylidene)-N4-phenyl pyrimidine-4,5-diamine 5A, N5-benzylidene-N4-phenylpyrimidine-4,5-diamine 5C, N5-benzylidene-N2, N2-dimethyl-N4-phenyl pyrimidine-2,4,5-triamine 5c, and N5-(4-methoxy benzylidene)-N4-phenyl pyrimidine-4,5-diamine 5E showed the highest significant anticancer activity. Based on the study, it was observed that substituents such as 4-hydroxy, 4-fluoro, 4-nitro, 4-methoxy, and 4-methyl are important to produce a biological effect. Moreover, among these substituents, N5-(4-hydroxybenzylidene)-N4-phenyl pyrimidine-4,5-diamine exhibited the highest anticancer activity followed by unsubstituted derivative N5-benzylidene-N4-phenylpyrimidine-4,5-diamine, which delivered significant anticancer activity.

Suppressed Vascular Leakage and Myocardial Edema Improve Outcome From Myocardial Infarction.

AimThe acute phase of myocardial infarction (MI) is accompanied by edema contributing to tissue damage and disease outcome. Here, we aimed to identify the mechanism whereby vascular endothelial growth factor (VEGF)-A induces myocardial edema in the acute phase of MI to eventually promote development of therapeutics to specifically suppress VEGFA-regulated vascular permeability while preserving collateral vessel formation.Methods and ResultsVEGFA regulates vascular permeability and edema by activation of VEGF receptor-2 (VEGFR2), leading to induction of several signaling pathways including the cytoplasmic tyrosine kinase c-Src. The activated c-Src in turn phosphorylates vascular endothelial (VE)-cadherin, leading to dissociation of endothelial adherens junctions. A particular tyrosine at position 949 in mouse VEGFR2 has been shown to be required for activation of c-Src. Wild-type mice and mice with phenylalanine replacing tyrosine (Y) 949 in VEGFR2 (Vegfr2Y949F/Y949F) were challenged with MI through permanent ligation of the left anterior descending coronary artery. The infarct size was similar in wild-type and mutant mice, but left ventricular wall edema and fibrinogen deposition, indicative of vascular leakage, were reduced in the Vegfr2Y949F/Y949F strain. When challenged with large infarcts, the Vegfr2Y949F/Y949F mice survived significantly better than the wild-type strain. Moreover, neutrophil infiltration and levels of myeloperoxidase were low in the infarcted Vegfr2Y949F/Y949F hearts, correlating with improved survival. In vivo tyrosine phosphorylation of VE-cadherin at Y685, implicated in regulation of vascular permeability, was induced by circulating VEGFA in the wild-type but remained at baseline levels in the Vegfr2Y949F/Y949F hearts.ConclusionSuppression of VEGFA/VEGFR2-regulated vascular permeability leads to diminished edema without affecting vascular density correlating with improved myocardial parameters and survival after MI.

Nanospheres Loaded with Curcumin Improve the Bioactivity of Umbilical Cord Blood-Mesenchymal Stem Cells via c-Src Activation During the Skin Wound Healing Process.

Curcumin, a hydrophobic polyphenol derived from turmeric, has been used a food additive and as a herbal medicine for the treatment of various diseases, but the clinical application of curcumin is restricted by its poor aqueous solubility and its low permeability and bioavailability levels. In the present study, we investigate the functional role of a nanosphere loaded with curcumin (CN) in the promotion of the motility of human mesenchymal stem cells (MSCs) during the skin wound healing process. CN significantly increased the motility of umbilical cord blood (UCB)-MSCs and showed 10,000-fold greater migration efficacy than curcumin. CN stimulated the phosphorylation of c-Src and protein kinase C which are responsible for the distinctive activation of the MAPKs. Interestingly, CN significantly induced the expression levels of α-actinin-1, profilin-1 and filamentous-actin, as regulated by the phosphorylation of nuclear factor-kappa B during its promotion of cell migration. In a mouse skin excisional wound model, we found that transplantation of UCB-MSCs pre-treated with CN enhanced wound closure, granulation, and re-epithelialization at mouse skin wound sites. These results indicate that CN is a functional agent that promotes the mobilization of UCB-MSCs for cutaneous wound repair.

C-Src and EGFR Inhibition in Molecular Cancer Therapy: What Else Can We Improve?

The proto-oncogene c-Src is a non-receptor tyrosine kinase playing a key role in many cellular pathways, including cell survival, migration and proliferation. c-Src de-regulation has been observed in several cancer types, making it an appealing target for drug discovery efforts. Recent evidence emphasizes its crucial role not only in promoting oncogenic traits, but also in the acquisition and maintenance of cancer resistance to various chemotherapeutic or molecular target drugs. c-Src modulates epidermal growth factor receptor (EGFR) activation and amplifies its downstream oncogenic signals. In this review, we report several studies supporting c-Src kinase role in the intricate mechanisms of resistance to EGFR tyrosine kinase inhibitors (TKIs). We further highlighted pre- and clinical progresses of combined treatment strategies made in recent years. Several pre-clinical data have encouraged the use of c-Src inhibitors in combination with EGFR inhibitors. However, clinical trials provided controversial outcomes in some cancer types. Despite c-Src inhibitors showed good tolerability in cancer patients, no incontrovertible and consistent clinical responses were recorded, supporting the idea that a better selection of patients is needed to improve clinical outcome. Currently, the identification of biological markers predictive of therapy response and the accurate molecular screening of cancer patients aimed to gain most clinical benefits become decisive and mandatory.

Studies on Structures and Functions of Kinases leading to Prostate Cancer and Their Inhibitors

Background:Cancer is the uncontrolled growth of abnormal cells in any part of the body. These abnormalities in the cells make them cancer cells, malignant cells, or tumour cells. These cells can infiltrate normal body tissues. Prostate Cancer begins when cells in the prostate gland start to grow out of control.Introduction:According to the National Cancer Institute, an estimated 20 percent of men experience Prostate Cancer in their lifetimes. Prostate Cancer can be divided into castration sensitive or hormone- sensitive Prostate Cancer (CSPC or HSPC) and castration-resistant Prostate Cancer (CRPC). Different therapies showed potential for the treatment of Prostate Cancer in that androgen receptor antagonist, cytochrome p17 inhibitors, radiation therapy, brachytherapy, surgical removal of the gland, androgen deprivation therapy and LnRH antagonists are some of the important ones. Despite various available treatment options in our understanding of the biological basis of Prostate Cancer, the management of the disease, especially in the castration-resistant phase, remains a significant challenge. Several Tyrosine kinase inhibitors (TKIs) have been evaluated in the preclinical setting in Advanced Prostate Cancer. TKIs are small drug molecules that work by competitive ATP inhibition at the catalytic binding site of tyrosine kinase. This results in complete inhibition of the catalytic activity of certain enzymes. If chosen correctly, TKIs can target and inhibit critical, mutated pathways important for the development, progression and metastasis of Prostate Cancer. The review focuses on various tyrosine kinase drug targets and their chemical structure to discuss the mechanism and pathways in the treatment of Prostate Cancer.Methods:The method adopted for the study was mainly based on the secondary search through a systematic literature review. Targets discussed in this review include the epidermal growth factor family (EGFR), vascular endothelial growth factor family (VEGF) receptor, c-Src family kinases (Proto-oncogene tyrosine-protein kinase) (c-Src), platelet-derived growth factor (PDGF) and cmesenchymal- epithelial transition factor (c-Met), which showed some promising results in various studies.Results:Even with the strong scientific rationale for many TKIs in the treatment of Prostate Cancer, the clinical trial experience showed some negative results in advanced phases. However, despite various challenges, the validation studies targeting kinases hold great potential in Prostate Cancer. Given the success of kinase inhibitors across multiple other cancer types, it is likely that this drug class will eventually improve outcomes in Prostate Cancer.Conclusion:Modifications in structures and certain other aspects of TKIs may make these agents promising for the treatment of Prostate Cancer.

Targeting c-Src Reverses Accelerated GPX-1 mRNA Decay in Chronic Obstructive Pulmonary Disease Airway Epithelial Cells.

Enhanced expression of the cellular antioxidant glutathione peroxidase (GPX)-1 prevents cigarette smoke-induced lung inflammation and tissue destruction. Subjects with chronic obstructive pulmonary disease (COPD), however, have decreased airway GPX-1 levels, rendering them more susceptible to disease onset and progression. The mechanisms that downregulate GPX-1 in the airway epithelium in COPD remain unknown. To ascertain these factors, analyses were conducted using human airway epithelial cells isolated from healthy subjects and human subjects with COPD and lung tissue from control and cigarette smoke-exposed A/J mice. Tyrosine phosphorylation modifies GPX-1 expression and cigarette smoke activates the tyrosine kinase c-Src. Therefore, studies were conducted to evaluate the role of c-Src on GPX-1 levels in COPD. These studies identified accelerated GPX-1 mRNA decay in COPD airway epithelial cells. Targeting the tyrosine kinase c-Src with siRNA inhibited GPX-1 mRNA degradation and restored GPX-1 protein levels in human airway epithelial cells. In contrast, silencing the tyrosine kinase c-Abl, or the transcriptional activator Nrf2, had no effect on GPX-1 mRNA stability. The chemical inhibitors for c-Src (saracatinib and dasanitib) restored GPX-1 mRNA levels and GPX-1 activity in COPD airway cells in vitro. Similarly, saracatinib prevented the loss of lung Gpx-1 expression in response to chronic smoke exposure in vivo. Thus, this study establishes that the decreased GPX-1 expression that occurs in COPD lungs is at least partially due to accelerated mRNA decay. Furthermore, these findings show that targeting c-Src represents a potential therapeutic approach to augment GPX-1 responses and counter smoke-induced lung disease.

C-Src kinase impairs the expression of mitochondrial OXPHOS complexes in liver cancer

Src family kinases (SFKs) play a crucial role in the regulation of multiple cellular pathways, including mitochondrial oxidative phosphorylation (OXPHOS). Aberrant activities of one of the most predominant SFKs, c-Src, was identified as a fundamental cause for dysfunctional cell signaling and implicated in cancer development and metastasis, especially in human hepatocellular carcinoma (HCC). Recent work in our laboratory revealed that c-Src is implicated in the regulation of mitochondrial energy metabolism in cancer. In this study, we investigated the effect of c-Src expression on mitochondrial energy metabolism by examining changes in the expression and activities of OXPHOS complexes in liver cancer biopsies and cell lines. An increased expression of c-Src was correlated with an impaired expression of nuclear- and mitochondrial-encoded subunits of OXPHOS complexes I and IV, respectively, in metastatic biopsies and cell lines. Additionally, we observed a similar association between high c-Src and reduced OXPHOS complex expression and activity in mouse embryonic fibroblast (MEF) cell lines. Interestingly, the inhibition of c-Src kinase activity with the SFK inhibitor PP2 and c-Src siRNA stimulated the expression of complex I and IV subunits and increased their enzymatic activities in both cancer and normal cells. Evidence provided in this study reveals that c-Src impairs the expression and function of mitochondrial OXPHOS complexes, resulting in a significant defect in mitochondrial energy metabolism, which can be a contributing factor to the development and progression of liver cancer. Furthermore, our findings strongly suggest that SFK inhibitors should be used in the treatment of HCC and other cancers with aberrant c-Src kinase activity to improve mitochondrial energy metabolism.

An Insight of Vitamin E as Neuroprotective Agents

Nervous system is the network of nerve cells that transmits nerve impulses throughout the body. It is rich in both unsaturated fats and irons, making it predominantly susceptible to oxidative stress and damage. Oxidative stress reflects the disruption of the redox balance between the formation and clearance of highly free radicals, for instance reactive oxygen species (ROS) and reactive nitrogen species (RNS). Oxidative stress will further damage the cell lipid, protein and DNA. Oxidative stress has a role in the modulation of critical cellular functions, such as apoptosis program activation, ion transport and calcium mobilization which lead to cell death. Many studies were conducted to prevent neuronal cell death caused by oxidative stress through administration of free radical scavenging antioxidant, such as vitamin E. Vitamin E is known as a chain-breaking antioxidant that showed the capability to increase the viability of neuronal cells that had undergone glutamate injury by inhibiting glutamate-induced pp60 (c-Src) kinase activation. Vitamin E occurs in 8 forms, namely ?-, ?-, ?- and ?-tocopherols and ?-, ?-, ?-and ?-tocotrienols. Tocotrienols differ from tocopherols by possessing an unsaturated isoprenoid side chain instead of a saturated phytyl tail. Tocotrienols, compared to tocopherols, are lightly studied due to the abundance of ?-tocopherol in the human body and its antioxidant properties. Nevertheless, recent studies showed that ?-tocotrienol is more effective in preventing lipid peroxidation compared to ?-tocopherol. Furthermore, tocotrienol was discovered to protect neuronal cell through antioxidant-independent activities. The tocotrienol-rich fraction (TRF) is an extract that consists of 75% tocotrienol and 25% ?-tocopherol. TRF was reported to possess potent antioxidant, anti-inflammation, anticancer and cholesterol-lowering properties. Thus, this writing highlights the significant neuroprotective effects of tocotrienol and tocopherol.

Effects of brain necroptosis and cytokines expression array on brain injury in rats with cardiac arrest

To investigate the underlying molecular mechanisms of brain injury in rats after cardiac arrest and cardiopulmonary resuscitation (CPR) by observing necroptosis of brain cells and changes of 90 cytokines in brain tissue. Sprague-Dawley (SD) rats were divided into Sham group (n = 10) and cardiac arrest group (n = 10) according to random number table method. The model of asphyxia cardiac arrest for 6 minutes followed by CPR model was established. Tracheal intubation in Sham rats were routinely performed without inducing cardiac arrest. Neurological deficit score (NDS) was evaluated, blood samples were collected and rats were sacrificed, then serum S100B level was measured by enzyme linked immunosorbent assay (ELISA) on the third day after CPR. Necroptotic cells in brain were detected by immunofluorescence staining. The levels of 90 cytokines expression in brain were measured by antibody array. The relative ratio of the two groups of protein expression ≥ 1.5 or ≤ 0.5 and P < 0.05 represented the differential expression protein. There were 8 rats successfully resuscitated and 2 died in cardiac arrest group. There were 8 rats selected in Sham group to match the sample size. Compared with Sham group, the NDS score of cardiac arrest group was significantly lower [63.0 (62.5, 64.3) vs. 80.0 (80.0, 80.0), P < 0.01], and the level of serum S100B was significantly higher (ng/L: 47.96±10.16 vs. 16.56±5.60, P < 0.01). More necroptotic cells in cerebral cortex and hippocampus were found in cardiac arrest group [proportion of cells positive for TdT-mediated nick end labeling (TUNEL) and negative for caspase-3: (15.70±0.32)% vs. (8.00±0.28)% in cortex, (20.80±1.35)% vs. (9.00±4.00)% in hippocampus, both P < 0.05]. The levels of inflammatory cytokines [cytokine-induced neutrophil chemoattractant (CINC-2α/β, CINC-3), interferon-γ (IFN-γ)] and signal protein c-Src kinase (CSK) in brain significantly increased after cardiac arrest as compared to Sham group levels (ratio of cardiac arrest group to Sham group: CINC-2 α/β was 2.503±0.428, P = 0.024; CINC-3 was 2.369±0.142, P = 0.005; IFN-γ was 3.149±1.362, P = 0.044; CSK was 1.887±0.105, P = 0.001). However, the levels of neuroprotective cytokines ciliary neurotrophic factor (CNTF), glial cell-derived neurotrophic factor receptor (GFR α-1, GFR α-2), growth hormone (GH), growth hormone receptor (GHR), granulocyte-macrophage colony-stimulating factor (GM-CSF) and anti-inflammatory protein interleukin-10 (IL-10) significantly decreased after cardiac arrest (ratio of cardiac arrest group to Sham group: CNTF was 0.341±0.137, P = 0.036; GFRα-1 was 0.461±0.164, P = 0.044; GFRα-2 was 0.447±0.017, P = 0.033; GH was 0.450±0.136, P = 0.024; GHR was 0.508±0.128, P = 0.022; GM-CSF was 0.446±0.130, P = 0.035; IL-10 was 0.502±0.211, P = 0.017). Necroptosis is involved in brain injury after cardiac arrest. The molecular mechanisms of brain injury may be related to inflammatory response, neurogenesis disorder and impaired survival of nerve cells.