Role of UPR Sensor Activation in Cell Death–Survival Decision of Colon Cancer Cells Stressed by DPE Treatment

Polyphenols have been shown to possess several beneficial properties, including properties involved in the prevention or treatment of cancer. Among these polyphenols, a leading role is played by dihydroxyphenylethanol (DPE), the most powerful antioxidant compound contained in the olive oil. DPE has been previously reported to induce endoplasmic reticulum (ER) stress and to reduce cell survival in colon cancer, one of the most common and aggressive cancers in developed countries. In this study, we further investigated the activation of UPR by DPE and explored the roles of the three UPR sensors, inositol-requiring enzyme (IRE) 1 alpha, protein kinase RNA-like endoplasmic reticulum kinase (PERK), and activating transcription factor (ATF6), in the cell death–survival decision of wt and mutp53 colon cancer cells and the underlying mechanisms involved. We also unveiled a new interplay between ATF6 and wt, as well as mutp53, which may have important implications in cancer therapy.

AMPK Is the Crucial Target for the CDK4/6 Inhibitors Mediated Therapeutic Responses in PANC-1 and MIA PaCa-2 Pancreatic Cancer Cell Lines

The survival rate of pancreatic ductal adenocarcinoma (PDAC) patients is short, and PDAC is a cancer type that ranks fourth in the statistics regarding death due to cancer. Mutation in the KRAS gene, which plays a role in pancreatic cancer development, activates the PI3K/AKT/mTOR signaling pathway. The activity of the AMPK as a cellular energy sensor is one of the fundamental mechanisms that can induce effective therapeutic responses against CDK4/6 inhibitors via adjusting the cellular and tumor microenvironment stress management. The phosphorylation of AMPKα at the different phosphorylation residues such as Thr172 and Ser 377 causes metabolic differentiation in the cells following CDK4/6 inhibitor treatment in accordance with an increased cell cycle arrest and senescence under the control of different cellular players. In this study, we examined the competencies of the CDK4/6 inhibitors LY2835219 and PD-0332991 on the mechanism of cell survival and death based on AMPK signaling. Both CDK4/6 inhibitors LY2835219 and PD-0332991 modulated different molecular players on the PI3K/AKT/mTOR and AMPK signaling axis in different ways to reduce cell survival in a cell type dependent manner. These drugs are potential inducers of apoptosis and senescence that can alter the therapeutic efficacy cells.

Gold Nanoparticles Radio-Sensitize and Reduce Cell Survival in Lewis Lung Carcinoma

It has been suggested that particle size plays an important role in determining the genotoxicity of gold nanoparticles (GNPs). The purpose of this study was to compare the potential radio-sensitization effects of two different sized GNPs (3.9 and 37.4 nm) fabricated and examined in vitro in Lewis lung carcinoma (LLC) as a model of non-small cell lung cancer through use of comet and clonogenic assays. After treatment with 2Gy X-ray irradiation, both particle sizes demonstrated increased DNA damage when compared to treatment with particles only and radiation alone. This radio-sensitization was further translated into a reduction in cell survival demonstrated by clonogenicity. This work indicates that GNPs of both sizes induce DNA damage in LLC cells at the tested concentrations, whereas the 37.4 nm particle size treatment group demonstrated greater significance in vitro. The presented data aids in the evaluation of the radiobiological response of Lewis lung carcinoma cells treated with gold nanoparticles.

Gold Nanoparticles Radio-sensitize and Reduce Cell Survival in Lewis Lung Carcinoma

It has been suggested that particle size plays an important role in determining the genotoxicity of gold nanoparticles (GNPs). The purpose of this study was to compare the potential radio-sensitization effects of two different sized GNPs (3.9 and 37.4 nm) fabricated and examined in vitro in Lewis Lung carcinoma (LLC) as a model of non-small cell lung cancer through use of comet and clonogenic assays. After the treatment of 2Gy X-ray irradiation, both particle sizes demonstrated increased DNA damage when compared to treatment with particles only and radiation alone. This radio-sensitization was further translated into a reduction in cell survival demonstrated by clonogenicity. This work indicates that GNPs of both sizes induce DNA damage in LLC cells at the tested concentrations, whereas the 37.4 nm particle size treatment group demonstrated greater significance in vitro. The presented data aids in the evaluation of the radiobiological response of Lewis Lung carcinoma cells treated with gold nanoparticles.

New Thalidomide-Resembling Dicarboximides Target ABC50 Protein and Show Antileukemic and Immunomodulatory Activities

We identified novel dicarboximides that were selectively cytotoxic towards human leukemia cells. Using chemical and biological methods, we characterized the biological activity, identified cellular protein targets and defined the mechanism of action of the test dicarboximides. The reported IC50 values (concentration required to reduce cell survival fraction to 50% of control) of selected dicarboximides were similar or lower than IC50 of registered anticancer drugs, for example cytarabine, sorafenib, irinotecan. Test compounds induced apoptosis in chronic myelogenous (K562) and acute lymphoblastic (MOLT-4) leukemia cells by activation of receptor and mitochondrial apoptotic pathways and increased the expression of proapoptotic genes (BAX, NOXA, HTRA2, TNFRSF10B, ESRRBL1). Selected dicarboximides displayed immunomodulatory activity and downregulated IKZF1 and IKZF3 transcription factors in K562 and MOLT-4 leukemia cells. ATP-binding cassette protein 50 (ABC50) was identified as a target for dicarboximides. Cancer cells with knocked down ABC50 showed increased resistance to dicarboximides. Based on the structure of dicarboximides and thalidomide, novel proteolysis-targeting chimeras (PROTACs) were synthesized and used as tools to downregulate ABC50 in leukemia cells.

AZD1208, a Pan-Pim Kinase Inhibitor, Has Anti-Growth Effect on 93T449 Human Liposarcoma Cells via Control of the Expression and Phosphorylation of Pim-3, mTOR, 4EBP-1, S6, STAT-3 and AMPK

Overexpression of Pim kinases has an oncogenic/pro-survival role in many hematological and solid cancers. AZD1208 is a pan-Pim kinase inhibitor that has anti-cancer and anti-adipogenic actions. Here, we investigated the effects of AZD1208 on the growth of 93T449 cells, a differentiated human liposarcoma cell line. At 20 µM, AZD1208 was cytotoxic (cytostatic) but not apoptotic, reducing cell survival without DNA fragmentation, caspase activation or increasing cells in the sub G1 phase; known apoptotic parameters. Notably, AZD1208 reduced phosphorylation of signal transducer and activator of transcription-3 (STAT-3) in 93T449 cells. STAT-3 inhibition by AG490, a JAK2/STAT-3 inhibitor similarly reduced cell survival. AZD1208 down-regulated phosphorylation of mammalian target of rapamycin (mTOR) and ribosomal S6 while up-regulated eukaryotic initiation factor-2α (eIF-2α). In addition, AZD1208 induced a LKB-1-independent AMPK activation, which was crucial for its cytostatic effect, as knock-down of AMPK greatly blocked AZD1208s ability to reduce cell survival. AZD1208 had no effect on expression of two members of Pim kinase family (Pim-1 and Pim-3) but inhibited phosphorylation of 4EBP-1, a downstream effector of Pim kinases. Importantly, a central role for Pim-3 in the actions of AZD1208 was confirmed by knock-down, which not only reduced 93T449 cell survival but also led to the inhibition of 4EBP-1, mTOR, eIF-2α and STAT-3, along with the activation of AMPK. In summary, this is the first report demonstrating that AZD1208 inhibits growth of liposarcoma cells and that this activity is mediated through Pim-3 kinase, STAT-3, mTOR, S6 and AMPK expression and phosphorylation pathways.

Different co-culture systems have the same impact on bovine embryo transcriptome

During the last few years, several co-culture systems using either BOEC or VERO feeder cells have been developed to improve bovine embryo development and these systems give better results at high oxygen concentration (20%). In parallel, the SOF medium, used at 5% O2, has been developed to mimic the oviduct fluid. Since 2010s, the SOF medium has become popular in improving bovine embryo development and authors have started to associate this medium to co-culture systems. Nevertheless, little is known about the putative benefit of this association on early development. To address this question, we have compared embryo transcriptomes in four different culture conditions: SOF with BOEC or VERO at 20% O2, and SOF without feeders at 5% or 20% O2. Embryos have been analyzed at 16-cell and blastocyst stages. Co-culture systems did not improve the developmental rate when compared to 5% O2. Direct comparison of the two co-culture systems failed to highlight major differences in embryo transcriptome at both developmental stages. Both feeder cell types appear to regulate the same cytokines and growth factors pathways, and thus to influence embryo physiology in the same way. In blastocysts, when compared to culture in SOF at 5% O2, BOEC or VERO seems to reduce cell survival and differentiation by, at least, negatively regulating STAT3 and STAT5 pathways. Collectively, in SOF medium both blastocysts rate and embryo transcriptome suggest no influence of feeder origin on bovine early development and no beneficial impact of co-culture systems when compared to 5% O2.

Chloroquine Has a Cytotoxic Effect on Acanthamoeba Encystation through Modulation of Autophagy

ABSTRACTEncystation ofAcanthamoeba castellaniiis associated with resistance to chemotherapeutic agents. Blocking the encystation process could potentiate the efficacy of chemotherapeutic agents and biocides. During encystation, autophagy is highly stimulated and required for proper encystation ofAcanthamoeba. In this study, the cytotoxic effect of chloroquine, a well-known autophagy-inhibitory drug, was tested inA. castellanii. Chloroquine was able to selectively reduce cell survival during the encystation ofA. castellanii. However,A. castellaniitrophozoites and mature cysts were resistant to chloroquine. Chloroquine treatment led to an increase in the number and size of lysosomes in encysting cells. Moreover, chloroquine inhibited the degradation of long-lived proteins in the encysting cells. Decreased autophagic flux, indicated by an increased number of lysosomes and decreased degradation of long-lived proteins, may be the mechanism by which cell death is induced by chloroquine in encystingAcanthamoeba. These results suggest a potential novel therapeutic application of chloroquine as an anti-Acanthamoebadrug. Our findings also suggest that targeting autophagy could be a therapeutic strategy againstAcanthamoebainfection.

The Study of Bortezomib Alone or in Combination with Arsenic Trioxide on Multidrug Resistance of HL60/ADR cells.

Abstract 4823 INTRODUCTION Proteĉ¢msome inhibitor bortezomib has used in treatment of hematology malignancies widely. We found it may reduce cell survival rate of HL60/ADR cell line and induce cell apoptosis in previous study. Now we are to investigate the effect of bortezomib alone or combined with arsenic trioxide (As2O3) on reversing multidrug resistance of HL60/ADR cell line and the possible machines. METHODS HL60/ADR cells were incubated with bortezomib at different doses alone and in combination with As2O3. The proliferation ratio was observed by MTT assay. Cell apoptosis was studied by fluorescence microscopy and flow cytometry. Intracellular concentration of daunorubicin (DNR) and multidrug resistance related protein-1 (MRP1) was determined by flow cytometry. P65Ap-p65Abcl-2AbaxAcaspase-3Acaspase-9APARP proteins were determined by western blot. RESULTS In bortezomib-treated tumor cells, inhibition rate increased in time- and dose-dependently, as well as apoptotic cells. Compared to bortezomib alone, combination with As2O3 inhibited the proliferation and induced the apoptosis of HL60/ADR cells more evident. Bortezomib can enhance the intraceflular accumulation of DNR and decrease MRP1 in HL60/ADM cells. The dual combination of As2O3 with bortezomib presents a superior anticancer and MRP1-decreased efficiency to either one of the drugs alone. Bortezomib can also elevate the expression of bax, caspase-3, caspase-9, PARP, and decelerate the expression of bcl-2, NF-κB p65, p-p65. CONCLUSIONS Bortezomib can reverse multidrug resistance of HL60/ADR cells and decrease the expression of MRP1 in cells. When combined with As2O3, it appears to synergistic effects. Its mechanisms might be associated with the inhibition of NF-κB activation, also with inhibiting anti-apoptosis proteins, boosting pro-apoptosis proteins, with followed activating caspase pathway. Disclosures: No relevant conflicts of interest to declare.

BMP7 is a podocyte survival factor and rescues podocytes from diabetic injury

In early diabetic renal injury, there is podocyte drop-out (but no decrease in the number of other glomerular cells) which is thought to cause glomerular proteinuria and subsequent diabetic glomerular injury. We tested the hypothesis that early diabetic podocyte injury is caused, in part, by downregulation of bone morphogenetic protein-7 (BMP7) and loss of its autocrine function in murine podocytes. High glucose (HG; 25 mM) induces rounding of differentiated podocytes and changes in the distribution of F-actin but without quantitative changes in E-cadherin and the podocyte markers podocin, CD2AP, Neph1, or synaptopodin. HG reduces BMP7 secretion and activity but does not affect BMP receptor levels in murine podocytes. In these cells, BMP7 effectively activates smad5 (but not smad1) and raises p38 phosphorylation [which is also increased by transforming growth factor-β (TGF-β)]. HG as well as TGF-β raise caspase-3 activity, increase apoptosis, and reduce cell survival which is, in part, blocked by BMP7. Knockdown and forced expression studies indicate that smad5 is required as well as sufficient for these actions of BMP7. These findings indicate that BMP7 is a differentiation and survival factor for podocytes, requires smad5, and can reduce diabetic podocyte injury.