Pro-survival Signaling Pathways Research Articles

Endosulfan induces cardiotoxicity through apoptosis via unbalance of pro-survival and mitochondrial-mediated apoptotic pathways

Although the associations between endosulfan and adverse cardiovascular health have been reported, the toxic effects and underlying mechanism of endosulfan on the heart are not well understood. In this study, we examined the cardiotoxicity induced by endosulfan using Wistar rats and human cardiomyocytes (AC16) cells. Wistar rats were divided into control group (received corn oil alone) and three concentrations of endosulfan groups (1, 5 and 10 mg/kg·bw) by gavage. The AC16 cells were treated with three various concentrations (0, 1.25, 5, and 20 μg/mL) of endosulfan. The results showed that endosulfan induced cytotoxicity through damaging myocardial structure, decreasing the viability of cardiomyocytes, and elevating the serum levels of cardiac troponin I, heart fatty acid binding protein, aspartate aminotransferase, and reactive oxygen species (p < 0.05). Moreover, measurement of mitochondrial function showed that endosulfan could significantly decrease adenosine triphosphate levels and cytochrome c oxidase IV expression in AC16 cells (p < 0.05). In addition, endosulfan obviously inhibited Bcl-2 expression, activated the expressions of cytochrome c/Caspase-9/Caspase-3 signaling pathway, and induced the apoptosis of AC16 cells (p < 0.05). Furthermore, endosulfan significantly increased the expression of Bim, and inhibited the expressions of PI3K/Akt/FoxO3a signaling pathways in cardiomyocytes (p < 0.05). These results suggest that endosulfan may induce cardiotoxicity by inducing myocardial apoptosis resulting from activation of mitochondria-mediated apoptosis pathway and inhibition of pro-survival signaling pathways, which might be helpful in elucidating the mechanism of cardiac dysfunction induced by endosulfan.

Expression analysis of apoptotic and survival genes in blood leukocytes of children with various forms of HHV-6 infection

Despite that human herpes virus type 6 (HHV-6) is extremely spread worldwide, molecular mechanisms of behind HHV-6 infection pathogenesis remain largely unexplored. No molecular markers were found linked to unfavorable course of HHV-6 infection which could allow to ease up selecting proper therapy and preventing development of complications. The aim of the study was to analyze expression of apoptosis and survival-related genes in blood leukocytes from 7–17-year-old children upon various forms of HHV-6 infection. The analysis was carried out by using DNA microarrays developed by us allowing to assess changes in expression level both of individual mRNAs and total gene set (-Σ). It was shown that during the acute phase of HHV-6 infection mRNA level was shifted toward pro-apoptotic factors. In the convalescence phase, most altered mRNA levels returned to normal. We have identified a set of mRNAs and genes whose expression level was significantly changed in acute disease phase. According to available data, these factors play an important role in regulation of studied signaling pathways. In order to search for HHV-6-associated factors, which markedly affect disease pattern of severe herpesvirus mixed infection, we analyzed significant changes of mRNA and genes expression levels in patients with severe HHV-6+EBV+CMV mixed infection and EBV+CMV mixed infection of moderate severity compared with healthy donors. The levels of 5 mRNAs (FAF1-NM_007051, DAPK2-NM_014326, CASP8AP2-NM_001137667, CASP8-NM_033356, BTK-NM_001287345) and 3 genes (FAS-Σ, Puma/BBC3-Σ, ITCH-Σ) were significantly increased in severe mixed infection comorbid with HHV-6 (EBV+CMV+HHV-6) but without HHV-6 (EBV+CMV) compared with healthy donors. Most of detected factors belong to Fas-mediated apoptosis pathway, and may be considered as candidate prognostic development factors of severe herpes virus infection involving HHV-6. This study profoundly extends existing understanding on molecular pathogenesis of HHV-6 infection involving apoptosis and pro-survival signaling pathways. Marked changes of mRNA and gene levels most likely contributed to the pathogenesis of HHV-6 as well as severe HHV-6+EBV+CMV mixed infection.

Inhibition of glioma cell viability by jatrophone via NF-κB down-regulation and apoptosis inhibitor up-regulation

IntroductionThe present study evaluated the pro-survival signaling pathway inhibition potential of jatrophone in glioblastoma cells with the intention to develop effective treatment for glioblastoma.Material and methodsChanges in proliferation of cells were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Morphological changes were evaluated by electron microscopy and apoptosis by flow cytometry.ResultsThe proliferative potential of glioma cells showed significant reduction on treatment with jatrophone. The shrinkage and detachment from the flask surface was prominent in glioma cells on treatment with 15 µM jatrophone. Treatment with jatrophone (4.8 µM) for 72 h increased apoptosis in U87MG and A172 cells. The immunocytochemistry showed a significant decrease in the level of intracellular NF-B p65 in glioma cells on treatment with jatrophone. Jatrophone treatment significantly suppressed nuclear NF-B p65/total NF-B p65 in glioma cells. Treatment with jatrophone suppressed levels of survivin, XIAP and Bcl-2 in glioma cells relative to control. The Bax level in glioma cells was enhanced markedly relative to control on treatment with jatrophone. Activation of caspase-9 and -3 in glioma cells was markedly increased on treatment with jatrophone.ConclusionsJatrophone acts as inhibitory agent for glioblastoma cell proliferation and mediator of apoptosis. Therefore, jatrophone can be used as a therapeutic agent for glioblastoma treatment.

LncRNA UCA1 Antagonizes Arsenic-Induced Cell Cycle Arrest through Destabilizing EZH2 and Facilitating NFATc2 Expression.

Arsenic (As) is a widespread metalloid contaminant, and its internal exposure is demonstrated to cause serious detrimental health problems. Albeit considerable studies are performed to interrogate the molecular mechanisms responsible for As‐induced toxicities, the exact mechanisms are not fully understood yet, especially at the epigenetic regulation level. In the present study, it is identified that long non‐coding RNA (lncRNA) urothelial cancer associated 1 (UCA1) alleviates As‐induced G2/M phase arrest in human liver cells. Intensive mechanistic investigations illustrate that UCA1 interacts with enhancer of zeste homolog 2 (EZH2) and accelerates the latter's protein turnover rate under normal and As‐exposure conditions. The phosphorylation of EZH2 at the Thr‐487 site by cyclin dependent kinase 1 (CDK1) is responsible for As‐induced EZH2 protein degradation, and UCA1 enhances this process through increasing the interaction between CDK1 and EZH2. As a consequence, the cell cycle regulator nuclear factor of activated T cells 2 (NFATc2), a downstream target of EZH2, is upregulated to resist As‐blocked cell cycle progress and cytotoxicity. In conclusion, the findings decipher a novel prosurvival signaling pathway underlying As toxicity from the perspective of epigenetic regulation: UCA1 facilitates the ubiquitination of EZH2 to upregulate NFATc2 and further antagonizes As‐induced cell cycle arrest.

Caffeine exposure ameliorates acute ischemic cell death in avian developing retina.

In infants, the main cause of blindness is retinopathy of prematurity that stems in a hypoxic-ischemic condition. Caffeine is a psychoactive compound that at low to moderate concentrations, selectively inhibits adenosine A1 and A2A receptors. Caffeine exerts beneficial effects in central nervous system of adult animal models and humans, whereas it seems to have malefic effect on the developing tissue. We observed that 48-h exposure (during synaptogenesis) to a moderate dose of caffeine (30mg/kg of egg) activated pro-survival signaling pathways, including ERK, CREB, and Akt phosphorylation, alongside BDNF production, and reduced retinal cell death promoted by oxygen glucose deprivation in the chick retina. Blockade of TrkB receptors and inhibition of CREB prevented caffeine protection effect. Similar signaling pathways were described in previously reported data concerning chemical preconditioning mechanism triggered by NMDA receptors activation, with low concentrations of agonist. In agreement to these data, caffeine increased NMDA receptor activity. Caffeine decreased the levels of the chloride co-transporter KCC2 and delayed the developmental shift on GABAA receptor response from depolarizing to hyperpolarizing. These results suggest that the caffeine-induced delaying in depolarizing effect of GABA could be facilitating NMDA receptor activity. DPCPX, an A1 adenosine receptor antagonist, but not A2A receptor inhibitor, mimicked the effect of caffeine, suggesting that the effect of caffeine occurs through A1 receptor blockade. In summary, an in vivo caffeine exposure could increase the resistance of the retina to ischemia-induced cell death, by triggering survival pathways involving CREB phosphorylation and BDNF production/TrkB activation.

Quantitative proteomic analysis identifies novel regulators of methotrexate resistance in choriocarcinoma

ObjectiveAlthough methotrexate (MTX) is commonly used for the treatment of choriocarcinoma, chemoresistance to MTX may occur in a considerable fraction of patients. Further understanding on the mechanisms of MTX resistance would help to develop more effective therapy for choriocarcinoma. MethodsQuantitative proteomic approach involving TMT labeling and LC-MS/MS was used to identify MTX resistance-related proteomic profiles in choriocarcinoma cell models. Pathway and process enrichment analysis were conducted to identify MTX resistance-related biological processes/molecular pathways. CCK-8 viability assay, clonogenic survival assay, and BrdU incorporation analysis were used to examine the chemosensitivity to MTX in choriocarcinoma cells. ResultsIn total, 5704 protein groups were identified, among which 4997 proteins were quantified. Bioinformatic analysis revealed that multiple biological processes/molecular pathways might be associated with MTX resistance in JEG3/JEG3/MTX cell systems. DPP4 and METTL7A were selected for further investigation. Increased expression of DPP4 or METTL7A was observed in MTX-resistant cancer cell lines and choriocarcinoma tissues. Knockdown of DPP4 or METTL7A significantly decreased cell viability, impaired clonogenesis, and increased apoptosis after MTX treatment in JEG3/MTX and JAR/MTX cells; while over-expression of DPP4 or METTL7A promoted cell viability and reduced apoptosis following exposure to MTX in JEG3, JAR and BEWO cells. Further, DPP4 and METTL7A differentially activated prosurvival signaling pathways including PI3K/AKT, ERK1/2 and STAT3, and attenuated the accumulation of reactive oxygen species (ROS) in choriocarcinoma cell lines. ConclusionsDPP4 and METTL7A might promote MTX resistance through activating pro-survival signaling pathways and attenuating the accumulation of ROS in choriocarcinoma cells. Targeting DPP4 and METTL7A might be useful to sensitize choriocarcinoma cells to MTX-based chemotherapy.

Integrin Subtypes and Nanoscale Ligand Presentation Influence Drug Sensitivity in Cancer Cells.

Cancer cell–matrix interactions have been shown to enhance cancer cell survival via the activation of pro-survival signaling pathways. These pathways are initiated at the site of interaction, i.e., integrins, and thus, their inhibition has been the target of therapeutic strategies. Individual roles for fibronectin-binding integrin subtypes αvβ3 and α5β1 have been shown for various cellular processes; however, a systematic comparison of their function in adhesion-dependent chemoresistance is lacking. Here, we utilize integrin subtype-specific peptidomimetics for αvβ3 and α5β1, both as blocking agents on fibronectin-coated surfaces and as surface-immobilized adhesion sites, in order to parse out their role in breast cancer cell survival. Block copolymer micelle nanolithography is utilized to immobilize peptidomimetics onto highly ordered gold nanoparticle arrays with biologically relevant interparticle spacings (35, 50, or 70 nm), thereby providing a platform for ascertaining the dependence of ligand spacing in chemoprotection. We show that several cellular properties—morphology, focal adhesion formation, and migration—are intricately linked to both the integrin subtype and their nanospacing. Importantly, we show that chemotherapeutic drug sensitivity is highly dependent on both parameters, with smaller ligand spacing generally hindering survival. Furthermore, we identify ligand type-specific patterns of drug sensitivity, with enhanced chemosurvival when cells engage αvβ3 vs α5β1 on fibronectin; however, this is heavily reliant on nanoscale spacing, as the opposite is observed when ligands are spaced at 70 nm. These data imply that even nanoscale alterations in extracellular matrix properties have profound effects on cancer cell survival and can thus inform future therapies and drug testing platforms.

Cell Death Pathways in Lymphoid Malignancies.

This review highlights the importance of the Bcl-2 family members in lymphoma cell survival and discusses the approaches to modulate their function, directly or indirectly, to advance lymphoma therapeutics. The balance of cell death versus survival is ultimately leveraged at the mitochondria. Mitochondrial outer membrane permeabilization (MOMP) is the critical event that governs the release of pro-apoptotic molecules from the intermembrane mitochondrial space. MOMP is achieved through the coordinated actions of pro- and anti-apoptotic Bcl-2 family member proteins. Recognition of functional alterations among the Bcl-2 family member proteins led to identification of tractable targets to combat hematologic malignancies. A new class of drugs, termed BH3 mimetics, was introduced in the clinic. Venetoclax, a Bcl-2 inhibitor, received regulatory approvals in therapy of chronic lymphocytic leukemia and acute myeloid leukemia. Alternative pro-survival Bcl-2 family proteins, in particular Mcl-1, have been successfully targeted in preclinical studies using novel-specific BH3 mimetics. Finally, anti-apoptotic Bcl-2 family members may be targeted indirectly, via interference with the pro-survival signaling pathways, e.g., phosphoinotiside-3 kinase, B-cell receptor signaling, and NF-κB.

Aloin Inhibits the Proliferation and Migration of Gastric Cancer Cells by Regulating NOX2-ROS-Mediated Pro-Survival Signal Pathways.

BackgroundAloin has been reported to have many pharmacological effects including anti-inflammatory, anti-oxidant and anti-tumour activities. However, the precise molecular mechanisms underlying the anti-tumour properties of aloin are yet to be elucidated.MethodsHGC-27 and BGC-823 gastric cancer cells were treated with aloin. EdU and colony formation assays were used to detect the proliferation ability of cells. The migration of cells was detected using wound healing and transwell assays. Western blotting was used to detect the levels of cyclinD1, cyclin E1, MMPs, N-cadherin, E-cadherin and NOX2. The phosphorylation of Akt, mTOR, P70S6K, S6, Src, stat3 and IκBα were also detected by Western blotting. Flow cytometry was used to detect the cell cycle distribution.The location of p65 in cells was determined by using a confocal microscopy assay. The total amounts of ROS present in cells were measured using an ROS assay kit.ResultsHere, we found that aloin inhibited the proliferation and migration of HGC-27 and BGC-823 gastric cancer cells using a combination of EdU, colony formation, wound healing and transwell assays. Further investigations revealed that aloin decreased the protein expression levels of cyclin D1, N-cadherin, and the matrix metalloproteinases (MMP)-2 and MMP-9; increased E-cadherin expression in a dose-dependent manner; inhibited reactive oxygen species (ROS) generation; and mediated the activation of Akt-mTOR, signal transducer and activator of transcription-3 (Stat3), and NF-κB signalling pathways. Our results also indicated that aloin is able to attenuate the expression levels of the two regulatory proteins of nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), p47phox and p22phox, but had no effect on the level of gp91phox. N-acetylcysteine treatment of gastric cancer cells inhibited ROS production and Akt-mTOR, Stat3, and IκBα phosphorylation. Taken together, our data suggest that aloin inhibits the proliferation and migration of gastric cancer cells by downregulating NOX2–ROS-mediated activation of the Akt-mTOR, Stat3, and NF-κB signalling pathways.ConclusionOur findings suggest a potential role for aloin in the prevention of gastric cancer cell proliferation and migration and provide novel insights into the anti-cancer properties of aloin.

The LINC00365/SCGB2A1 (Mammaglobin B) Axis Down-Regulates NF-κB Signaling and Is Associated with the Progression of Gastric Cancer.

PurposeA lack of early diagnostic biomarkers and therapeutic targets has led to poor prognosis for gastric cancer patients. However, the analysis of cancer-associated genomic data has been shown to be effective in identifying potential markers. Recently, the long non-coding RNA LINC00365 and SCGB2A1 gene (as known as mammaglobin B) were predicted to be co-expressed in gastric cancer based on the Gene Expression Omnibus database. However, their precise role in gastric cancer tumors is still not clear.MethodsThe expressions of LINC00365 and SCGB2A1 in gastric cancer tissues were investigated using qPCR and their expressions were detected in a gastric cancer tissue microarray by in situ hybridization and immunohistochemical staining. The functions of LINC00365 in BGC-823 and MGC-803 gastric cancer cells were tested using the MTT assay, flow cytometry, colony formation assay, EDU staining, immunofluorescence and luciferase assay.ResultsWe found that LINC00365 and SCGB2A1 mRNA were both expressed at low levels in 30 cases of gastric cancer. Gastric cancer tissue microarray analysis indicated that LINC00365 and SCGB2A1 were expressed at low levels in tumor tissue, and low expression of both factors correlated with shorter survival time. Functional studies showed that LINC00365 overexpression significantly inhibited gastric cancer cell viability through the impairment of proliferation rather than the promotion of apoptosis. Furthermore, overexpressed LINC00365 upregulated SCGB2A1 in gastric cancer cell lines. Immuno-fluorescence and luciferase assay analysis indicated that LINC00365 overexpression inhibited the NF-κB pro-survival signaling pathway. Consistent with the effects of LINC00365, SCGB2A1 upregulation also reduced cell survival and inactivated NF-κB.ConclusionCollectively, our findings revealed that SCGB2A1 may be the target coding protein regulated by LINC00365 in gastric cancer. LINC00365 and SCGB2A1 may function as tumor suppressors and may serve as potential prognostic and therapeutic markers in gastric cancer treatment.

Bio-Inspired Functional Lipoprotein-like Nanoparticles (Flip-NPs) Cause Cholesterol Starvation and Ferroptosis in B-Cell Lymphomas: Studies in Cell Lines, Xenograft Models and Primary Patient Samples

Introduction: Hematologic malignancies, including B cell lymphomas such as diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL), have increased demands for cholesterol and cholesteryl esters to maintain membrane anchored pro-proliferative and pro-survival signaling pathways, including B cell receptor signaling. Recent evidence suggests that certain cancer cell lines, including several anaplastic large T cell lymphoma (ALCL) cell lines, are auxotrophic for cholesterol and are sensitive to cholesterol reduction-induced ferroptosis (Garcia-Bermudez, Nature 2019), an iron dependent form of programmed cell death characterized by accumulation of lipid peroxides. We have developed a cholesterol depleting functional lipoprotein-like nanoparticle (Flip-NP) that specifically targets the high-affinity HDL receptor, scavenger receptor type B1 (SCARB1), which maintains cellular and cell membrane cholesterol homeostasis. Our prior data demonstrated that Flip-NPs induce B cell lymphoma cell death in vitro and in in vivo xenograft models. Accordingly, we hypothesized that the mechanism of cell death by Flip-NPs in B cell lymphomas is ferroptosis, and that Flip-NPs would be potent therapy for an expanded number of cholesterol-addicted malignancies, including ALCL. Methods: After informed consent, primary B cell lymphoma cells were isolated from excisional biopsies from patients with FL or DLBCL. The SUDHL4 [germinal center (GC) DLBCL], Ramos [Burkitt's lymphoma], SUDHL1 [ALCL] and SR-786 [ALCL] cell lines were used for in vitro experiments. SCARB1 expression was quantified using flow cytometry and western blot analysis. Cell viability was quantified using the MTS assay and flow cytometry. Ferroptosis was measured using the lipophilic antioxidant ferrostatin-1 or the iron chelator deferoxamine. Gene expression changes were quantified using RT-qPCR. Lipid peroxidation was measured using C11-BODIPY and flow cytometry. SUDHL1 and SUDHL4 flank tumor xenografts were initiated in SCID-beige mice, with Flip-NPs administered 3 times per week IV. Results: Primary B cell lymphoma cells were isolated from patients with FL (n=4) or DLBCL (n=2), and all samples expressed some level of SCARB1 by flow cytometry. Flip-NPs increased cell death in 3 of the 4 FL samples and 1 of 2 DLBCL samples. In Ramos and SUDHL4 cells, RT-qPCR data showed that Flip-NP-mediated cholesterol reduction led to up-regulation of cholesterol biosynthesis genes and down-regulation of glutathione peroxidase-4 (GPX4), a critical protein responsible for degradation of lipid peroxides. Correspondingly, as shown with C11-BODIPY, Flip-NP treatment increased lipid peroxide accumulation in Ramos and SUDHL4 cells. Addition of ferrostatin-1 or deferoxamine reduced Flip-NP induced cell death, demonstrating that the mechanism-of-action of Flip-NPs involves, at least in part, ferroptosis. Given the sensitivity of cholesterol auxotrophic cell lines to cholesterol reduction-induced ferroptosis, we tested the efficacy of the Flip-NPs against cholesterol auxotrophic ALK+ ALCL cell lines SUDHL1 and SR-786. SCARB1 was expressed in both cell lines. Flip-NPs potently induced cell death in both SUDHL1 and SR-786 cells in vitro. In vivo, systemic administration of Flip-NPs reduced tumor volumes in both SUDHL4 and SUDHL1 tumor xenograft models. Conclusions: Our data show that Flip-NPs reduce GPX4 expression and increase lipid peroxide accumulation in B cell lymphoma cell lines, resulting in ferroptosis. Expanding on these results, Flip-NP efficacy was also demonstrated in cholesterol auxotrophic ALK+ ALCL cell lines and primary patient-derived B cell lymphoma cells. These in vitro results translated to in vivo murine models, as systemic administration of Flip-NPs potently reduced DLBCL and ALK+ ALCL tumor xenograft burden. Flip-NPs are a molecularly targeted, first-in-class therapy that may be effective for malignancies reliant upon cellular cholesterol. Disclosures Behdad: Pfizer: Other: Speaker; Thermo Fisher: Membership on an entity's Board of Directors or advisory committees; Loxo-Bayer: Membership on an entity's Board of Directors or advisory committees. Karmali:Astrazeneca: Speakers Bureau; Takeda, BMS: Other: Research Funding to Institution; Gilead/Kite; Juno/Celgene: Consultancy, Speakers Bureau. Thaxton:Zylem: Other: Co-founder of the biotech company Zylem. Gordon:Juno/Celgene: Other: Advisory Board, Research Funding; Gilead: Other: Advisory Board; Bayer: Other: Advisory Board; Zylem LLC: Other: co-founder; research in nanoparticles in cancer.

Pro-Death or Pro-Survival: Contrasting Paradigms on Nanomaterial-Induced Autophagy and Exploitations for Cancer Therapy.

Autophagy is a critical lysosome-mediated cellular degradation process for the clearance of damaged organelles, obsolete proteins, and invading pathogens and plays important roles in the pathogenesis and treatment of human diseases including cancer. While not a cell death process per se, autophagy is nevertheless intimately linked to a cell's live/die decision. Basal autophagy, operating constitutively at low levels in essentially every mammalian cell, is vital for maintaining cellular homeostasis and promotes cell survival. On the other hand, elevated level of autophagy is frequently observed in cells responding to a physical, chemical, or biological stress. This "induced" autophagy, a hallmark under a variety of pathological and pathophysiological conditions, may be either pro-death or pro-survival, two contrasting paradigms for cell fate determination. Research in our laboratory and other groups around the world over the last 15 years has revealed nanomaterials as a unique class of autophagy inducers, with the capability of elevating the cellular autophagy to extremely high levels. In this Account we focus on the contrasting cell fate decision impacted by nanomaterial-induced autophagy. First, we give a brief introduction to nanomaterial-induced autophagy and summarize our current understanding on how it affects a cell's live/die decision. Autophagy induced by nanomaterials, in most cases, promotes cell death, but a significant number of nanomaterials are also able to elicit pro-survival autophagy. Although not a common feature, some nanomaterials may induce pro-death autophagy in one cell type while eliciting pro-survival autophagy in a different cell type. The ability to control the level of the induced autophagy, and furthermore its pro-death/pro-survival nature, is critically important for nanomedicine. Second, we discuss several possible mechanistic insights on the pro-death/pro-survival decision for nanomaterial-induced autophagy. "Disrupted" autophagic processes, with a "block" or perhaps "diversion" at the various stages, may be a characteristic hallmark for nanomaterial-induced autophagy, rendering it intrinsically pro-death in nature. On the other hand, autophagy-mediated upregulation and activation of pro-survival factors or signaling pathways, overriding the intrinsic pro-death nature, may be a common mechanism for nanomaterial-induced pro-survival autophagy. In addition, cargo degradation and reactive oxygen species may also play important roles in the pro-death/pro-survival decision impacted by nanomaterial-induced autophagy. Finally, we focus on the situation where nanomaterials induce autophagy in cancer cells and summarize the different strategies in exploiting the pro-death or pro-survival nature of nanomaterial-induced autophagy to enhance the various modalities of cancer therapy, including direct cancer cell killing, chemotherapy and radiotherapy, photothermal therapy, and integrated diagnosis and therapy. While the details vary, the basic principle is simple and straightforward. If the induced autophagy is pro-death, maximize it. Otherwise, inhibit it. Effective exploitation of nanomaterial-induced autophagy has the potential to become a new weapon in our ever-increasing arsenal to fight cancer, particularly difficult-to-treat and drug-resistant cancer.

Platelet-Derived Growth Factor Receptor and Ionizing Radiation in High Grade Glioma Cell Lines.

Treatment of high grade gliomas (HGGs) has remained elusive due to their high heterogeneity and aggressiveness. Surgery followed by radiotherapy represents the mainstay of treatment for HGG. However, the unfavorable location of the tumor that usually limits total resection and the resistance to radiation therapy are the major therapeutic problems. Chemotherapy with DNA alkylating agent temozolomide is also used to treat HGG, despite modest effects on survival. Disregulation of several growth factor receptors (GFRs) were detected in HGG and receptor amplification in glioblastoma has been suggested to be responsible for heterogeneity propagation through clonal evolution. Molecularly targeted agents inhibiting these membrane proteins have demonstrated significant cytotoxicity in several types of cancer cells when tested in preclinical models. Platelet-derived growth factor receptors (PDGFRs) and associated signaling were found to be implicated in gliomagenesis, moreover, HGG commonly display a Platelet-derived growth factor (PDGF) autocrine pathway that is not present in normal brain tissues. We have previously shown that both the susceptibility towards PDGFR and the impact of the PDGFR inactivation on the radiation response were different in different HGG cell lines. Therefore, we decided to extend our investigation, using two other HGG cell lines that express PDGFR at the cell surface. Here, we investigated the effect of PDGFR inhibition alone or in combination with gamma radiation in 11 and 15 HGG cell lines. Our results showed that while targeting the PDGFR represents a good means of treatment in HGG, the combination of receptor inhibition with gamma radiation did not result in any discernable difference compared to the single treatment. The PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways are the major signaling pathways emerging from the GFRs, including PDGFR. Decreased sensitivity to radiation-induced cell death are often associated with redundancy in these pro-survival signaling pathways. Here we found that Phosphoinositide 3-kinases (PI3K), Extracellular-signal-regulated kinase 1/2 (ERK1/2), or c-Jun N-terminal kinase 1/2 (JNK1/2) inactivation induced radiosensitivity in HGG cells.

Effect of topical administration of the microneurotrophin BNN27 in the diabetic rat retina.

Diabetic retinopathy (DR) is a complex eye disease associated with diabetes mellitus. It is characterized by three pathophysiological components, namely microangiopathy, neurodegeneration, and inflammation. We recently reported that intraperitoneal administration of BNN27, a novel neurosteroidal microneurotrophin, reversed the diabetes-induced neurodegeneration and inflammation in rats treated with streptozotocin (STZ), by activating the NGF TrkA and p75 receptors. The aim of the present study was to investigate the efficacy of BNN27 to protect retinal neurons when applied topically as eye drops in the same model. The STZ rat model of DR was employed. BNN27 was administered as eye drops to diabetic Sprague-Dawley rats for 7days, 4weeks post-STZ (70mg/kg) injection. Immunohistochemistry and western blot analyses were employed to examine the viability of retinal neurons in control, diabetic, and diabetic-treated animals and the involvement of the TrkA receptor and its downstream signaling ERK1/2 kinases, respectively. BNN27 reversed the STZ-induced attenuation of the immunoreactive brain nitric oxide synthetase (bNOS)- and tyrosine hydroxylase (TH)-expressing amacrine cells and neurofilament (NFL)-expressing ganglion cell axons in a dose-dependent manner. In addition, BNN27 activated/phosphorylated the TrkA receptor and its downstream prosurvival signaling pathway, ERK1/2 kinases. The results of this study provide solid evidence regarding the efficacy of BNN27 as a neuroprotectant to the diabetic retina when administered topically, and suggest that its pharmacodynamic and pharmacokinetic profiles render it a putative therapeutic for diabetic retinopathy.

Radiation‐activated prosurvival signaling pathways in cancer cells

AbstractRadiation therapy is a standard treatment for local disease control of solid tumors. Although radiation therapy has significantly improved the overall survival and quality of life of cancer patients, its efficacy has been limited by the development of radiation resistance and the presence of residual disease after therapy, leading to cancer recurrence. Radiation induces cytotoxicity in cancer cells, mainly by causing DNA damage. However, concurrently radiation can also activate multiple protective signaling pathways, such as ataxia telangiectasia mutated/ataxia telangiectasia mutated and Rad3‐related protein, phosphoinositide‐3‐kinase/protein kinase B, extracellular signal‐regulated kinase, and nuclear factor‐κB, which promote cell cycle checkpoint activation, leading to cell cycle arrest/DNA repair and inhibition of apoptosis. Conjointly, these signaling pathways protect cancer cells by reducing the magnitude of radiation‐induced cytotoxicity and promoting radioresistance of cancer cells. Thus, targeting these prosurvival pathways could have great potential for sensitizing cancer cells to radiation therapy. In the present review, we summarize the current literature on the radiation‐activated prosurvival signaling pathways that promote radioresistance.

Angiotensin II-induced micro RNA-21 culprit for non-small-cell lung adenocarcinoma.

Lung cancer is among the most complicated cancers, with an estimated 1.6 million deaths each year for both men and women. However, the proportion of lung cancer patients in developing nations has increased from 31% to 49.9% in the last two decades. There are two main subtypes of lung cancer, small-cell lung carcinoma and non-small-cell lung carcinoma (NSCLC), accounting for 15% and 85% of all lung cancer, respectively. Adenocarcinoma is the most common type of lung cancer in smokers and nonsmokers in men and women regardless of their age. Chemicals in cigarette smoke and nicotine enter our bloodstream and can then affect the entire body and finally lead to the activation of several important, pro-survival signaling pathways. The biologically active peptide of RAAS on overstimulation enhance Ang II mediates cell proliferation, fibrosis and inflammatory effects via AT1 receptor. Very few studies highlight the diagnostic and therapeutic potential of miRNAs with the EGFR-regulated miRNA-21.

Targeting Tax Interacting Protein 1 Results in Cytotoxic and Radiosensitizing Effects in Cancer

Abstract INTRODUCTION Poor survival of patients afflicted with glioblastoma continues to fuel the search for new molecular targets to improve therapy. Previously we have shown that Tax interacting protein 1 (TIP1), a protein known to be involved in cancer progression, is overexpressed and radiation-inducible in gliolblastoma. In this study, we investigated the effect of anti-TIP1 antibodies on glioblastoma in vitro and in vivo. METHODS We analyzed the expression profile of TIP1 in glioblastoma via the cancer genome atlas. Radiation induction of TIP1 was confirmed in tumor-bearing mice with near infrared imaging after exposure to ionizing radiation (XRT). We assessed the effect of TIP1 antibodies on cell proliferation and compared these to genetic knockout of TIP1 mediated by CRISPR/Cas9. We assessed the affinity of TIP1 antibodies with surface plasmon resonance.The mTOR pathway was analyzed by western blot following antibody treatment, and cell death was assessed with Annexin-V/PI by flow cytometry. Tumor growth delay was assessed in Vivo by measuring tumor volumes over time in mice bearing heterotopic tumors treated with/without TIP antibody and XRT. RESULTS We found that antibody binding to the functional domain of TIP1 results in endocytosis of the antibody-protein complex and subsequent cytotoxicity. We also show that these antibodies bound with high affinity to cancer cells and synergized with ionizing radiation to enhance net cytotoxicity in vitro and delay tumor growth in Vivo. These effects were also associated with downregulation of mTOR-AKT signaling. CONCLUSION TIP1 is a new therapeutic target for cancer treatment that may be combined with ionizing radiation therapy to enhance treatment efficacy. The mechanism of TIP1-mediated cytotoxicty involves endocytosis of protein-antibody complexes with associated reduction in pro-survival signaling pathways.

Abstract 738: Comparative Cardiotoxicity of Tyrosine Kinase Inhibitors Ponatinib and PF114

Background: The advent of tyrosine kinase inhibitor (TKI) targeted therapy revolutionized the treatment of chronic myelogenous leukemia (CML) patients, leading to a significant impact on remission rates and overall survival. However, cardiotoxicity associated with these targeted therapies put the cancer survivors at greater risk. Ponatinib is an example shown unexpected wide spectrum of cardiotoxic complications which limits its clinical applications. A newly designed 4 th -generation tyrosine kinase inhibitor PF114 having better target spectra in CML, could be a potential alternative to ponatinib. But the cardiotoxic potential of PF114 is not yet fully understood. Objectives: The objectives of the present study were to compare cardiotoxicity of ponatinib with PF114. Methods: In this study, we employed zebrafish transgenic BNP reporter line that expresses luciferase under control of the nppb promoter ( nppb : F-Luciferase) to compare cardiotoxic potential of TKIs. We also exploited NRVMs to explore cardiotoxic mechanism associated with ponatinib and PF114. Results: We observed that increasing dose of PF114 showed minimal induction of the BNP reporter compared to ponatinib. PF114 did not reduce the ventricular fractional shortening in zebrafish as compared to ponatinib. Consistently, in cultured rat cardiomyocytes, PF114 could not reiterate the same cardiotoxic effect of ponatinib as depicted by cell viability and TUNEL assay. Mechanistically, PF114 has shown no effects on essential prosurvival AKT and ERK signaling pathway while ponatinib is known to exerts its cardiotoxic effects by their inhibition. Additionally, the allosteric tyrosine kinase inhibitor ABL001(Asciminib) in combination with PF114 depicts less pronounced cardiotoxic effects than ponatinib in similar settings. Conclusions: This study provides further rationale to utilize zebrafish for the prediction of cardiotoxicity of anticancer drugs. The comparative cardiotoxicity of ponatinib and PF114 suggest that PF114 is a significantly less cardiotoxic analogue and safer treatment option than ponatinib for CML patients harboring BCR/ABL-T315I “gatekeeper” mutation.

PTEN Tumor-Suppressor: The Dam of Stemness in Cancer.

PTEN is one of the most frequently inactivated tumor suppressor genes in cancer. Loss or variation in PTEN gene/protein levels is commonly observed in a broad spectrum of human cancers, while germline PTEN mutations cause inherited syndromes that lead to increased risk of tumors. PTEN restrains tumorigenesis through different mechanisms ranging from phosphatase-dependent and independent activities, subcellular localization and protein interaction, modulating a broad array of cellular functions including growth, proliferation, survival, DNA repair, and cell motility. The main target of PTEN phosphatase activity is one of the most significant cell growth and pro-survival signaling pathway in cancer: PI3K/AKT/mTOR. Several shreds of evidence shed light on the critical role of PTEN in normal and cancer stem cells (CSCs) homeostasis, with its loss fostering the CSC compartment in both solid and hematologic malignancies. CSCs are responsible for tumor propagation, metastatic spread, resistance to therapy, and relapse. Thus, understanding how alterations of PTEN levels affect CSC hallmarks could be crucial for the development of successful therapeutic approaches. Here, we discuss the most significant findings on PTEN-mediated control of CSC state. We aim to unravel the role of PTEN in the regulation of key mechanisms specific for CSCs, such as self-renewal, quiescence/cell cycle, Epithelial-to-Mesenchymal-Transition (EMT), with a particular focus on PTEN-based therapy resistance mechanisms and their exploitation for novel therapeutic approaches in cancer treatment.

Vitamin C induces human melanoma A375 cell apoptosis via Bax- and Bcl-2-mediated mitochondrial pathways.

Melanoma is the most malignant type of skin cancer and is resistant to numerous chemotherapeutic and radiotherapy-based treatment approaches due to the activation of rapid and reversible pro-survival signaling pathways. As a result, patients will often present with a poor prognosis. Therefore, novel preventive methods and treatments are urgently required for patients with melanoma. Vitamin C (also known as L-ascorbic acid) is a water-soluble vitamin that is widely used as a dietary additive and has been demonstrated to exhibit anti-cancer properties. In the present study, the effects of vitamin C in human melanoma A375 cells, and the mechanisms underlying these effects were investigated. Vitamin C potently suppressed human melanoma A375 cell proliferation by inducing apoptosis in A375 cells. Induction of apoptosis was related to caspase-9 and caspase-3 activation and the mitochondrial membrane potential of A375 cells significantly decreased in the presence of vitamin C. Furthermore, vitamin C induced apoptosis in A375 cells by activating the Bax- and Bcl-2-mediated mitochondrial pathway. These results indicate that vitamin C may be a potentially useful clinical anti-tumor drug for treating patients with melanoma.