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1.
Mol Hum Reprod ; 26(1): 30-39, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31814016

ABSTRACT

Dienogest, a specific progesterone receptor agonist, is used in the treatment of endometriosis. However, it is still unclear as to the mechanisms of therapeutic effects on endometriosis. Our recent study showed that endometriosis may be the result of aberrant endoplasmic reticulum (ER) stress induction due to progesterone resistance. This finding suggests that the regulation of ER stress induction may play a key role in treatment of endometriosis. Therefore, the anti-endometriotic effects of dienogest may be mediated by regulation of ER stress. To test this hypothesis, we elucidate whether dienogest affects endometriotic stromal cell apoptosis, proliferation and invasiveness by modulating ER stress-induced CCAAT/enhancer-binding protein homologous protein (CHOP) expression. Specifically, PRKR-like ER kinase (PERK)/eukaryotic initiation factor 2α (eIF2α)/activating transcription factor 4 (ATF4), inositol-requiring kinase 1 (IRE1)/TNF receptor-associated factor 2 (TRAF2)/apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) signaling, and downstream CHOP were evaluated to determine the involved ER stress-mediated regulation mechanism of CHOP expression. Our results show that progesterone treatment did not have any significant effects on ER stress, apoptosis, proliferation, and invasion in estrogen-treated endometriotic cyst stromal cells (ECSCs). However, dienogest treatment upregulated the induction of ER stress. It also led to increased apoptosis, and decreased proliferation and invasiveness. These dienogest-induced changes in apoptosis, proliferation and invasiveness were reversed by the ER stress inhibitor salubrinal. Furthermore, dienogest-induced ER stress increased CHOP expression through activation of both PERK/elf2α/ATF4 and IRE1/TRAF2/ASK1/JNK signaling. This upregulation was blocked by transfection with PERK and IRE1 siRNA, which decreased apoptosis and increased the proliferation and invasiveness of dienogest-treated ECSCs. Taken together, our findings indicate that dienogest enhances ER stress induction in endometriotic stromal cells, which affects apoptosis, proliferation and invasiveness via CHOP upregulation.


Subject(s)
Cysts/drug therapy , Endometriosis/drug therapy , Endoplasmic Reticulum Stress/drug effects , Hormone Antagonists/pharmacology , Nandrolone/analogs & derivatives , Transcription Factor CHOP/genetics , eIF-2 Kinase/genetics , Activating Transcription Factor 4/genetics , Activating Transcription Factor 4/metabolism , Adult , Apoptosis/drug effects , Cell Movement/drug effects , Cell Proliferation/drug effects , Cysts/genetics , Cysts/metabolism , Cysts/pathology , Endometriosis/genetics , Endometriosis/metabolism , Endometriosis/pathology , Endometrium/drug effects , Endometrium/metabolism , Endometrium/pathology , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/metabolism , Endoribonucleases/antagonists & inhibitors , Endoribonucleases/genetics , Endoribonucleases/metabolism , Female , Gene Expression Regulation , Humans , MAP Kinase Kinase Kinase 5/genetics , MAP Kinase Kinase Kinase 5/metabolism , MAP Kinase Signaling System , Nandrolone/pharmacology , Progesterone/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Stromal Cells/drug effects , Stromal Cells/metabolism , Stromal Cells/pathology , TNF Receptor-Associated Factor 2/genetics , TNF Receptor-Associated Factor 2/metabolism , Transcription Factor CHOP/agonists , Transcription Factor CHOP/metabolism , eIF-2 Kinase/antagonists & inhibitors , eIF-2 Kinase/metabolism
2.
J Biochem ; 164(6): 415-426, 2018 Dec 01.
Article in English | MEDLINE | ID: mdl-30165670

ABSTRACT

A small nuclear protein, C1D, has roles in various cellular processes, transcription regulation, genome stability surveillance, DNA repair and RNA processing, all of which are required to maintain the host life cycles. In the previous report, C1D directly interacts with XPB, a component of the nucleotide excision repair complex, and C1D knockdown reduced cell survival of 27-1 cells, CHO derivative cells, after UV irradiation. To find out the role of C1D in UV-damaged cells, we used human cell lines with siRNA or shRNA to knockdown C1D. C1D knockdown reduced cell survival rates of LU99 and 786-O after UV irradiation, although C1D knockdown did not affect the efficiency of the nucleotide excision repair. Immunostaining data support that C1D is not directly involved in the DNA repair process in UV-damaged cells. However, H2O2 treatment reduced cell viability in LU99 and 786-O cells. We also found that C1D knockdown upregulated DDIT3 expression in LU99 cells and downregulated APEX1 in 786-O cells, suggesting that C1D functions as a co-repressor/activator. The data accounts for the reduction of cell survival rates upon UV irradiation.


Subject(s)
Co-Repressor Proteins/metabolism , DNA Repair/radiation effects , DNA-(Apurinic or Apyrimidinic Site) Lyase/metabolism , DNA/metabolism , Gene Expression Regulation, Enzymologic/radiation effects , Oxidative Stress/radiation effects , Transcription Factor CHOP/metabolism , Animals , Biomarkers/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Cell Survival/radiation effects , Co-Repressor Proteins/antagonists & inhibitors , Co-Repressor Proteins/genetics , DNA Damage , DNA Repair/drug effects , DNA, Neoplasm/metabolism , DNA-(Apurinic or Apyrimidinic Site) Lyase/antagonists & inhibitors , DNA-(Apurinic or Apyrimidinic Site) Lyase/chemistry , DNA-(Apurinic or Apyrimidinic Site) Lyase/genetics , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/radiation effects , Humans , Hydrogen Peroxide/toxicity , Oxidants/toxicity , Oxidative Stress/drug effects , Pyrimidine Dimers/metabolism , RNA Interference , Radiation Injuries, Experimental/enzymology , Radiation Injuries, Experimental/metabolism , Radiation Injuries, Experimental/pathology , Transcription Factor CHOP/agonists , Transcription Factor CHOP/antagonists & inhibitors , Transcription Factor CHOP/genetics
3.
Mol Nutr Food Res ; 62(8): e1700890, 2018 04.
Article in English | MEDLINE | ID: mdl-29446867

ABSTRACT

SCOPE: We investigated the role of endoplasmic reticulum (ER) stress in the protective effects of EGCG against the neuronal apoptosis in Aß1-42 -induced SH-SY5Y cells and APP/PS1 transgenic mice. METHODS AND RESULTS: Cell viability (CCK8 assay), flow cytometry, Hoechst 33258 staining, immunohistochemistry, transmission electron microscopy (TEM), and western blotting were used. EGCG prevented Aß1-42-induced toxicity in SH-SY5Y cells, increased cell viability, and decreased apoptosis in a dose-dependent manner. In a subsequent mechanism study, it was found that this effect contributed to the down-regulation of GRP78, CHOP, cleaved-caspase-12 and -3. Moreover, EGCG also reduced the cytotoxicity induced by tunicamycin (TM) and thapsigargin (TG), two ER stress activators. Consistent with the in vitro study, EGCG inhibited neuronal apoptosis in the cortex of APP/PS1 transgenic mice, with the mitigation of ER abnormal ultrastructural swelling and the downregulation of ER-stress-associated proteins. CONCLUSION: These results indicate that EGCG attenuates the neurotoxicity in Alzheimer's disease (AD) via a novel mechanism that involves inhibition of ER-stress-associated neuronal apoptosis in vitro and in vivo, suggesting the tremendous potential of EGCG for use in a nutritional preventive strategy against AD.


Subject(s)
Amyloid beta-Peptides/antagonists & inhibitors , Apoptosis , Catechin/analogs & derivatives , Dietary Supplements , Endoplasmic Reticulum Stress , Neurons/metabolism , Neuroprotective Agents/metabolism , Peptide Fragments/antagonists & inhibitors , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/prevention & control , Amyloid beta-Peptides/metabolism , Animals , Caspase 12/chemistry , Caspase 12/genetics , Caspase 12/metabolism , Caspase 3/chemistry , Caspase 3/genetics , Caspase 3/metabolism , Catechin/metabolism , Catechin/therapeutic use , Cell Line, Tumor , Cell Survival , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Cerebral Cortex/ultrastructure , Endoplasmic Reticulum Chaperone BiP , Heat-Shock Proteins/agonists , Heat-Shock Proteins/antagonists & inhibitors , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Humans , Mice, Transgenic , Microscopy, Electron, Transmission , Nerve Tissue Proteins/agonists , Nerve Tissue Proteins/antagonists & inhibitors , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurons/pathology , Neurons/ultrastructure , Neuroprotective Agents/therapeutic use , Nootropic Agents/metabolism , Nootropic Agents/therapeutic use , Peptide Fragments/metabolism , Random Allocation , Transcription Factor CHOP/agonists , Transcription Factor CHOP/antagonists & inhibitors , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism
4.
Arch Physiol Biochem ; 124(2): 131-138, 2018 May.
Article in English | MEDLINE | ID: mdl-28857622

ABSTRACT

CONTEXT: Molecular pathogenesis of chronic alcoholism is linked to increased endoplasmic reticulum stress. Ethanol is a competitive inhibitor of vitamin A metabolism and vitamin A supplementation aggravates existing liver problems. Hence, we probed into the impact of supplementation of all trans retinoic acid (ATRA), the active metabolite of vitamin A on ethanol-induced endoplasmic reticulcum stress. METHODS: Male Sprague-Dawley rats were divided into four groups - I: Control; II: Ethanol; III: ATRA; IV: ATRA + Ethanol. After 90 days the animals were sacrificed to study markers of lipid peroxidation in hepatic microsomal fraction and expression of ER stress proteins and apoptosis in liver. RESULTS AND CONCLUSION: Ethanol caused hepatic hyperlipidemia, enhanced microsomal lipid peroxidation, upregulated expression of unfolded protein response associated proteins and that of apoptosis. Ethanol also led to downregulation of retinoid receptors. ATRA supplementation reversed all these alterations indicating the decrease in ethanol-induced endoplasmic reticulum stress.


Subject(s)
Dietary Supplements , Endoplasmic Reticulum Stress , Fatty Liver, Alcoholic/prevention & control , Liver/metabolism , Protective Agents/therapeutic use , Receptors, Retinoic Acid/agonists , Tretinoin/therapeutic use , Activating Transcription Factor 4/agonists , Activating Transcription Factor 4/antagonists & inhibitors , Activating Transcription Factor 4/genetics , Activating Transcription Factor 4/metabolism , Animals , Apoptosis/drug effects , Biomarkers/metabolism , Cytochrome P-450 CYP2E1/chemistry , Cytochrome P-450 CYP2E1/genetics , Cytochrome P-450 CYP2E1/metabolism , Endoplasmic Reticulum Stress/drug effects , Ethanol/toxicity , Fatty Liver, Alcoholic/enzymology , Fatty Liver, Alcoholic/metabolism , Gene Expression Regulation/drug effects , Lipid Metabolism/drug effects , Lipid Peroxidation/drug effects , Liver/drug effects , Liver/enzymology , Male , Rats, Sprague-Dawley , Receptors, Retinoic Acid/antagonists & inhibitors , Receptors, Retinoic Acid/genetics , Receptors, Retinoic Acid/metabolism , Retinoid X Receptors/agonists , Retinoid X Receptors/antagonists & inhibitors , Retinoid X Receptors/genetics , Retinoid X Receptors/metabolism , Transcription Factor CHOP/agonists , Transcription Factor CHOP/antagonists & inhibitors , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism , Tretinoin/antagonists & inhibitors , Unfolded Protein Response/drug effects , X-Box Binding Protein 1/agonists , X-Box Binding Protein 1/antagonists & inhibitors , X-Box Binding Protein 1/genetics , X-Box Binding Protein 1/metabolism
5.
Mol Hum Reprod ; 23(12): 842-854, 2017 12 01.
Article in English | MEDLINE | ID: mdl-29121349

ABSTRACT

STUDY QUESTION: Does the flavonoid naringenin inhibit proliferation of human endometriosis cells? SUMMARY ANSWER: Naringenin suppresses proliferation and increases apoptosis via depolarization of mitochondrial membrane potential and generation of reactive oxygen species (ROS) in human endometriosis cells. WHAT IS KNOWN ALREADY: For management of endometriosis, hormonal therapy is commonly used to decrease production of estrogens by the ovaries, but that has limitations including undesirable side effects with long-term therapies. To overcome these limitations, it is important to discover novel compounds which have no adverse effects, but inhibit expression of target molecules involved in the pathogenesis of endometriosis. STUDY DESIGN SIZE, DURATION: Well-established endometriosis cell lines (VK2/E6E7 and End1/E6E7) were purchased from the American Type Culture Collection. Effects of naringenin on VK2/E6E7 and End1/E6E7 cells were assessed in diverse assays in a dose- and time-dependent manner. PARTICIPANTS/MATERIALS, SETTING, METHODS: Effects of naringenin on viability, apoptosis (Annexin V expression, propidium iodide staining, TUNEL and invasion assays), mitochondria-mediated apoptosis, production of ROS and endoplasmic reticulum (ER) stress proteins of VK2/E6E7 and End1/E6E7 cells were determined. Signal transduction pathways in VK2/E6E7 and End1/E6E7 cells in response to naringenin were determined by western blot analyses. MAIN RESULTS AND THE ROLE OF CHANCE: In the present study, we demonstrated that naringenin suppressed proliferation and increased apoptosis through depolarization of mitochondrial membrane potential and inducing pro-apoptotic proteins, Bax and Bak, in both endometriosis cell lines. In addition, naringenin increased ROS, ER stress, through activation of eIF2α and IRE1α, GADD153 and GRP78 proteins in a dose-dependent manner. Furthermore, the induction of apoptosis by naringenin involved activation of MAPK and inactivation of PI3K pathways in VK2/E6E7 and End1/E6E7 cells. LIMITATIONS REASONS FOR CAUTION: Lack of in vivo animal studies is a major limitation of this research. Effectiveness of naringenin to induce apoptosis of human endometriosis cells requires further investigation. WIDER IMPLICATIONS OF THE FINDINGS: Our results suggest that naringenin is a promising therapeutic compound for treatment of endometriosis in women. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (No. HI15C0810 awarded to G.S. and HI17C0929 awarded to W.L.). The authors declare that there are no conflicts of interest.


Subject(s)
Endoplasmic Reticulum Stress/drug effects , Estrogen Antagonists/pharmacology , Flavanones/pharmacology , Mitochondria/drug effects , Mitogen-Activated Protein Kinases/genetics , Stromal Cells/drug effects , Annexin A5/genetics , Annexin A5/metabolism , Apoptosis/drug effects , Cell Line , Dose-Response Relationship, Drug , Endometriosis/metabolism , Endometriosis/pathology , Endometrium/metabolism , Endometrium/pathology , Endoplasmic Reticulum Chaperone BiP , Endoribonucleases/genetics , Endoribonucleases/metabolism , Eukaryotic Initiation Factor-2/agonists , Eukaryotic Initiation Factor-2/genetics , Eukaryotic Initiation Factor-2/metabolism , Female , Gene Expression Regulation , Heat-Shock Proteins/agonists , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Humans , Membrane Potential, Mitochondrial/drug effects , Mitochondria/metabolism , Mitogen-Activated Protein Kinases/metabolism , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Reactive Oxygen Species/agonists , Reactive Oxygen Species/metabolism , Signal Transduction , Stromal Cells/metabolism , Stromal Cells/pathology , Transcription Factor CHOP/agonists , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism , bcl-2 Homologous Antagonist-Killer Protein/agonists , bcl-2 Homologous Antagonist-Killer Protein/genetics , bcl-2 Homologous Antagonist-Killer Protein/metabolism , bcl-2-Associated X Protein/agonists , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolism
6.
J Biol Regul Homeost Agents ; 31(1): 77-80, 2017.
Article in English | MEDLINE | ID: mdl-28337873

ABSTRACT

Cyclosporine-A induces gingival overgrowth with disturbance in the homeostasis of cells and connective tissue proteins. Human gingival fibroblasts were cultured with cyclosporine A, and the expression of two vital endoplasmic stress markers and two prime matrix proteins (connective tissue growth factor (CTGF and periostin) were assessed by RT-PCR. We found that expression of Glucose-Regulated Protein 78 (GRP78/BIP) and CCAAT/enhancer binding protein, C/EBP homologous protein (CHOP) were significantly increased, along with CTGF and periostin, suggesting a role for these factors in gingival overgrowth.


Subject(s)
Cell Adhesion Molecules/genetics , Connective Tissue Growth Factor/genetics , Cyclosporine/adverse effects , Endoplasmic Reticulum Stress/drug effects , Heat-Shock Proteins/genetics , Immunosuppressive Agents/adverse effects , Transcription Factor CHOP/genetics , Biomarkers/metabolism , Cell Adhesion Molecules/agonists , Cell Adhesion Molecules/metabolism , Connective Tissue Growth Factor/agonists , Connective Tissue Growth Factor/metabolism , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Chaperone BiP , Endoplasmic Reticulum Stress/genetics , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Gene Expression Regulation , Gingiva/cytology , Gingiva/drug effects , Gingiva/metabolism , Heat-Shock Proteins/agonists , Heat-Shock Proteins/metabolism , Humans , Primary Cell Culture , Signal Transduction , Transcription Factor CHOP/agonists , Transcription Factor CHOP/metabolism
7.
Sci Rep ; 6: 32582, 2016 09 01.
Article in English | MEDLINE | ID: mdl-27581364

ABSTRACT

We have purified physapubescin, a predominant steroidal lactone, from medicinal plant Physalis pubescens L., commonly named as "hairy groundcherry" in English and "Deng-Long-Cao" in Chinese. Von Hippel-Lindau (VHL)-null 786-O, RCC4 and A498 Renal Cell Carcinoma (RCC) cell lines expressing high levels of Hypoxia Inducible Factor (HIF)-2α are more sensitive to physapubescin-mediated apoptosis and growth inhibitory effect than VHL wild-type Caki-2 and ACHN RCC cell lines. Restoration of VHL in RCC4 cells attenuated the growth inhibitory effect of physapubescin. Physapubescin decreases the expression of HIF-2α and increases the expression of CCAAT/enhancer-binding protein homologus protein (CHOP), which leads to up-regulation of death receptor 5 (DR5), activation of caspase-8 and -3, cleavage of poly (ADP-Ribose) polymerase (PARP) and apoptosis. Under hypoxia conditions, the apoptotic and growth inhibitory effects of physapubescin are further enhanced. Additionally, physapubescin synergizes with TNF-related apoptosis-inducing ligand (TRAIL) for markedly enhanced induction of apoptosis in VHL-null 786-O cells but not in VHL wild-type Caki-2 cells. Physapubescin significantly inhibited in vivo angiogenesis in the 786-O xenograft. Physapubescin as a novel agent for elimination of VHL-null RCC cells via apoptosis is warranted for further investigation.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/genetics , Carcinoma, Renal Cell/drug therapy , Gene Expression Regulation, Neoplastic , Kidney Neoplasms/drug therapy , Neovascularization, Pathologic/prevention & control , Von Hippel-Lindau Tumor Suppressor Protein/genetics , Withanolides/pharmacology , Animals , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Basic Helix-Loop-Helix Transcription Factors/antagonists & inhibitors , Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinoma, Renal Cell/genetics , Carcinoma, Renal Cell/metabolism , Carcinoma, Renal Cell/pathology , Caspase 3/genetics , Caspase 3/metabolism , Caspase 8/genetics , Caspase 8/metabolism , Cell Line, Tumor , Gene Deletion , Humans , Hypoxia/drug therapy , Hypoxia/genetics , Hypoxia/metabolism , Hypoxia/pathology , Kidney Neoplasms/genetics , Kidney Neoplasms/metabolism , Kidney Neoplasms/pathology , Mice , Mice, Nude , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/metabolism , Neovascularization, Pathologic/pathology , Physalis/chemistry , Poly(ADP-ribose) Polymerases/genetics , Poly(ADP-ribose) Polymerases/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics , Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism , Signal Transduction , TNF-Related Apoptosis-Inducing Ligand/pharmacology , Transcription Factor CHOP/agonists , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism , Tumor Burden/drug effects , Von Hippel-Lindau Tumor Suppressor Protein/metabolism , Xenograft Model Antitumor Assays
8.
Mar Drugs ; 13(4): 2376-89, 2015 Apr 16.
Article in English | MEDLINE | ID: mdl-25894488

ABSTRACT

Avarol is a sesquiterpenoid hydroquinone with potent cytotoxicity. Although resolving endoplasmic reticulum (ER) stress is essential for intracellular homeostasis, erratic or excessive ER stress can lead to apoptosis. Here, we reported that avarol selectively induces cell death in pancreatic ductal adenocarcinomas (PDAC), which are difficult to treat owing to the availability of few chemotherapeutic agents. Analyses of the molecular mechanisms of avarol-induced apoptosis indicated upregulation of ER stress marker BiP and ER stress-dependent apoptosis inducer CHOP in PDAC cells but not in normal cells, suggesting that avarol selectively induces ER stress responses. We also showed that avarol activated the PERK-eIF2α pathway but did not affect the IRE1 and ATF6 pathways. Moreover, CHOP downregulation was significantly suppressed by avarol-induced apoptosis. Thus, the PERK-eIF2α-CHOP signaling pathway may be a novel molecular mechanism of avarol-induced apoptosis. The present data indicate that avarol has potential as a chemotherapeutic agent for PDAC and induces apoptosis by activating the PERK-eIF2α pathway.


Subject(s)
Antineoplastic Agents/pharmacology , Carcinoma, Pancreatic Ductal/drug therapy , Pancreatic Neoplasms/drug therapy , Sesquiterpenes/pharmacology , Signal Transduction/drug effects , Transcription Factor CHOP/agonists , eIF-2 Kinase/metabolism , Animals , Antineoplastic Agents/adverse effects , Apoptosis/drug effects , Biomarkers/metabolism , Carcinoma, Pancreatic Ductal/metabolism , Cell Line , Cell Line, Tumor , Dysidea/chemistry , Endoplasmic Reticulum Chaperone BiP , Endoplasmic Reticulum Stress/drug effects , Eukaryotic Initiation Factor-2/agonists , Eukaryotic Initiation Factor-2/metabolism , Gene Expression Regulation, Neoplastic/drug effects , Heat-Shock Proteins/agonists , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Humans , Inhibitory Concentration 50 , Neoplasm Proteins/agonists , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Pancreatic Neoplasms/metabolism , RNA Interference , Sesquiterpenes/adverse effects , Transcription Factor CHOP/antagonists & inhibitors , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism , Up-Regulation/drug effects , eIF-2 Kinase/chemistry
9.
BMC Cancer ; 14: 431, 2014 Jun 13.
Article in English | MEDLINE | ID: mdl-24927938

ABSTRACT

BACKGROUND: A common approach to cancer therapy in clinical practice is the combination of several drugs to boost the anticancer activity of available drugs while suppressing their unwanted side effects. In this regard, we examined the efficacy of combination treatment with the widely-used genotoxic drug doxorubicin and the mitochondriotoxic Hsp90 inhibitor gamitrinib to exploit disparate stress signaling pathways for cancer therapy. METHODS: The cytotoxicity of the drugs as single agents or in combination against several cancer cell types was analyzed by MTT assay and the synergism of the drug combination was evaluated by calculating the combination index. To understand the molecular mechanism of the drug synergism, stress signaling pathways were analyzed after drug combination. Two xenograft models with breast and prostate cancer cells were used to evaluate anticancer activity of the drug combination in vivo. Cardiotoxicity was assessed by tissue histology and serum creatine phosphokinase concentration. RESULTS: Gamitrinib sensitized various human cancer cells to doxorubicin treatment, and combination treatment with the two drugs synergistically increased apoptosis. The cytotoxicity of the drug combination involved activation and mitochondrial accumulation of the proapoptotic Bcl-2 family member Bim. Activation of Bim was associated with increased expression of the proapoptotic transcription factor C/EBP-homologous protein and enhanced activation of the stress kinase c-Jun N-terminal kinase. Combined drug treatment with doxorubicin and gamitrinib dramatically reduced in vivo tumor growth in prostate and breast xenograft models without increasing cardiotoxicity. CONCLUSIONS: The drug combination showed synergistic anticancer activities toward various cancer cells without aggravating the cardiotoxic side effects of doxorubicin, suggesting that the full therapeutic potential of doxorubicin can be unleashed through combination with gamitrinib.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis Regulatory Proteins/agonists , Doxorubicin/pharmacology , Membrane Proteins/agonists , Proto-Oncogene Proteins/agonists , Animals , Antineoplastic Agents/administration & dosage , Apoptosis/drug effects , Apoptosis Regulatory Proteins/metabolism , Bcl-2-Like Protein 11 , Cell Line, Tumor , Cell Survival/drug effects , Disease Models, Animal , Doxorubicin/administration & dosage , Drug Synergism , Humans , Membrane Proteins/metabolism , Mice , Mitochondria/drug effects , Mitochondria/metabolism , Neoplasms/drug therapy , Neoplasms/metabolism , Neoplasms/pathology , Proto-Oncogene Proteins/metabolism , Transcription Factor CHOP/agonists , Transcription Factor CHOP/metabolism , Tumor Burden/drug effects , Xenograft Model Antitumor Assays
10.
Photochem Photobiol ; 88(5): 1135-40, 2012.
Article in English | MEDLINE | ID: mdl-22118157

ABSTRACT

UVA radiation (315-400 nm), which constitutes ca 95% of the UV irradiation in natural sunlight reaching earth surface, is a major environmental risk factor associated with human skin cancer pathogenesis. UVA is an oxidizing agent that causes significant damage to cellular components through the release of reactive oxygen species (ROS) and leads to photoaging and photocarcinogenesis. Here we investigate the effect of silibinin, the flavonolignan from Silybum marianum, on UVA-induced ROS and cell death in human keratinocyte cell line HaCaT. In addition, the effect of silibinin on UVA-induced intracellular ROS-mediated endoplasmic reticulum (ER) stress was also analyzed. UVA irradiation resulted in ROS production and apoptosis in HaCaT cells in a dose-dependent manner, and the ROS levels and apoptotic index were found to be elevated significantly when the cells were treated with 75 µmsilibinin for 2 h before UVA exposure. When the cells were pretreated with 10 mmN-acetyl cysteine, the enhancement of UVA-induced apoptosis by silibinin was compromised. Furthermore, we found that silibinin enhances ER stress-mediated apoptosis in HaCaT cells by increasing the expression of CHOP protein. These results suggest that silibinin may be beneficial in the removal of UVA-damaged cells and the prevention of skin cancer.


Subject(s)
Endoplasmic Reticulum Stress/drug effects , Keratinocytes/drug effects , Photosensitizing Agents/pharmacology , Silybum marianum/chemistry , Silymarin/pharmacology , Acetylcysteine/pharmacology , Antioxidants/pharmacology , Apoptosis/drug effects , Apoptosis/radiation effects , Cell Line , Cell Survival/drug effects , Cell Survival/radiation effects , Dose-Response Relationship, Radiation , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/radiation effects , Endoplasmic Reticulum Stress/radiation effects , Gene Expression/drug effects , Gene Expression/radiation effects , Humans , Keratinocytes/metabolism , Keratinocytes/radiation effects , Oxidative Stress/drug effects , Oxidative Stress/radiation effects , Reactive Oxygen Species/agonists , Reactive Oxygen Species/metabolism , Silybin , Transcription Factor CHOP/agonists , Transcription Factor CHOP/genetics , Ultraviolet Rays/adverse effects
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