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Curcumin induces endoplasmic reticulum stress-associated apoptosis in human papillary thyroid carcinoma BCPAP cells via disruption of intracellular calcium homeostasis.
Zhang, L, Cheng, X, Xu, S, Bao, J, Yu, H
Medicine. 2018;(24):e11095
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Abstract
BACKGROUND Thyroid cancer is the most common endocrine tumor. Our previous studies have demonstrated that curcumin can induce apoptosis in human papillary thyroid carcinoma BCPAP cells. However, the underlined mechanism has not been clearly elucidated. Endoplasmic reticulum (ER) is a major organelle for synthesis, maturation, and folding proteins as well as a large store for Ca. Overcoming chronically activated ER stress by triggering pro-apoptotic pathways of the unfolded protein response (UPR) is a novel strategy for cancer therapeutics. Our study aimed to uncover the ER stress pathway involved in the apoptosis caused by curcumin. METHODS BCPAP cells were treated with different doses of curcumin (12.5-50 μM). Annexin V/PI double staining was used to determine cell apoptosis. Rhod-2/AM calcium fluorescence probe assay was performed to measure the calcium level of endoplasmic reticulum. Western blot was used to examine the expression of ER stress marker C/EBP homologous protein 10 (CHOP) and glucose-regulated protein 78 (GRP78). X-box binding protein1 (XBP-1) spliced form was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS Curcumin significantly inhibited anchorage-independent cell growth and induced apoptosis in BCPAP cells. Curcumin induced ER stress and UPR responses in a dose- and time-dependent manner, and the chemical chaperone 4-phenylbutyrate (4-PBA) partially reversed the antigrowth activity of curcumin. Moreover, curcumin significantly increased inositol-requiring enzyme 1α (IRE1α) phosphorylation and XBP-1 mRNA splicing to induce a subsets of ER chaperones. Increased cleavage of activating transcription factor 6 (ATF6), which enhances expression of its downstream target CHOP was also observed. Furthermore, curcumin induced intracellular Ca influx through inhibition of the sarco-endoplasmic reticulum ATPase 2A (SERCA2) pump. The increased cytosolic Ca then bound to calmodulin to activate calcium/calmodulin-dependent protein kinase II (CaMKII) signaling, leading to mitochondrial apoptosis pathway activation. Ca chelator BAPTA partially reversed curcumin-induced ER stress and growth suppression, confirming the possible involvement of calcium homeostasis disruption in this response. CONCLUSIONS Curcumin inhibits thyroid cancer cell growth, at least partially, through ER stress-associated apoptosis. Our observations provoked that ER stress activation may be a promising therapeutic target for thyroid cancer treatment.(Figure is included in full-text article.).
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Smokeless tobacco consumption impedes metabolic, cellular, apoptotic and systemic stress pattern: A study on Government employees in Kolkata, India.
Biswas, S, Manna, K, Das, U, Khan, A, Pradhan, A, Sengupta, A, Bose, S, Ghosh, S, Dey, S
Scientific reports. 2015;:18284
Abstract
Smokeless tobacco (SLT) remains a threat amongst a large population across the globe and particularly in India. The oral use of tobacco has been implicated to cause physiological stress leading to extreme toxicological challenge. The study included 47 SLT-users and 44 non-users providing a spectrum of pathophysiological, clinico-biochemical, antioxidant parameters, cell cycle progression study of PBMC and morphological changes of red blood cells (RBC). The expressions of p53, p21, Bax, Bcl-2, IL-6, TNF- α, Cox-2, iNOS were analyzed from thirteen representative SLT-users and twelve non-users. Difference in CRP, random glucose, serum cholesterol, TG, HLDL-C, LDL-C, VLDL-C, neutrophil count, monocyte count, ESR, SOD (PBMC) and TBARS (RBC membrane) were found to be statistically significant (p < 0.05) between the studied groups. The current study confers crucial insight into SLT mediated effects on systemic toxicity and stress. This has challenged the metabolic condition leading to a rise in the inflammatory status, increased apoptosis and RBC membrane damage. The above findings were substantiated with metabolic, clinical and biochemical parameters. This is possibly the first ever in-depth report and remains an invaluable document on the fatal effects of SLT.
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Biological effects of leukotriene E4 on eosinophils.
Steinke, JW, Negri, J, Payne, SC, Borish, L
Prostaglandins, leukotrienes, and essential fatty acids. 2014;(3):105-10
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Abstract
Studies demonstrate the existence of novel receptors for cysteinyl leukotrienes (CysLTs) that are responsive to leukotriene (LT) E4 and might be pathogenic in asthma. Given the eosinophilic infiltration in this disorder, we investigated eosinophil expression of P2Y12 and gpr99 and their capacity to respond to LTE4. Receptor transcript expression was investigated via quantitative PCR and surface protein expression via flow cytometry. We investigated LTE4 influences on eosinophils including Ca(+2) flux, cAMP induction, modulation of adhesion molecule expression, apoptosis and degranulation. Eosinophils displayed both transcript and surface protein expression of P2Y12 and gpr99. We could not find evidence of LTE4 activation of eosinophils, however, LTE4 induced cAMP expression, and preincubation of eosinophils with LTE4 inhibited degranulation. Even though eosinophils are an important source of CysLTs in AERD, eosinophils are not themselves the pro-inflammatory biological target and, in contrast, LTE4 via cAMP primarily elicits anti-inflammatory responses.
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The antiparasitic clioquinol induces apoptosis in leukemia and myeloma cells by inhibiting histone deacetylase activity.
Cao, B, Li, J, Zhu, J, Shen, M, Han, K, Zhang, Z, Yu, Y, Wang, Y, Wu, D, Chen, S, et al
The Journal of biological chemistry. 2013;(47):34181-34189
Abstract
The antiparasitic clioquinol (CQ) represents a class of novel anticancer drugs by interfering with proteasome activity. In the present study, we found that CQ induced blood cancer cell apoptosis by inhibiting histone deacetylases (HDACs). CQ accumulated the acetylation levels of several key proteins including histone H3 (H3), p53, HSP90, and α-tubulin. In the mechanistic study, CQ was found to down-regulate HDAC1, -3, -4, and -5 in both myeloma and leukemia cells. Computer modeling analysis revealed that CQ was well docked into the active pocket of the enzyme, where the oxygen and nitrogen atoms in CQ formed stable coordinate bonds with the zinc ion, and the hydroxyl group from CQ formed an effective hydrogen bond with Asp-267. Moreover, co-treatment with CQ and zinc/copper chloride led to decreased Ac-H3. Furthermore, CQ inhibited the activity of Class I and IIa HDACs in the cell-free assays, demonstrating that CQ interfered with HDAC activity. By inhibiting HDAC activity, CQ induced expression of p21, p27, and p53, cell cycle arrest at G1 phase, and cell apoptosis. This study suggested that the HDAC enzymes are targets of CQ, which provided a novel insight into the molecular mechanism of CQ in the treatment of hematological malignancies.
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Cathepsin D primes caspase-8 activation by multiple intra-chain proteolysis.
Conus, S, Pop, C, Snipas, SJ, Salvesen, GS, Simon, HU
The Journal of biological chemistry. 2012;(25):21142-51
Abstract
During the resolution of inflammatory responses, neutrophils rapidly undergo apoptosis. A direct and fast activation of caspase-8 by cathepsin D was shown to be crucial in the initial steps of neutrophil apoptosis. Nevertheless, the activation mechanism of caspase-8 remains unclear. Here, by using site-specific mutants of caspase-8, we show that both cathepsin D-mediated proteolysis and homodimerization of caspase-8 are necessary to generate an active caspase-8. At acidic pH, cathepsin D specifically cleaved caspase-8 but not the initiator caspase-9 or -10 and significantly increased caspase-8 activity in dimerizing conditions. These events were completely abolished by pepstatin A, a pharmacological inhibitor of cathepsin D. The cathepsin D intra-chain proteolysis greatly stabilized the active site of caspase-8. Moreover, the main caspase-8 fragment generated by cathepsin D cleavage could be affinity-labeled with the active site probe biotin-VAD-fluoromethyl ketone, suggesting that this fragment is enzymatically active. Importantly, in an in vitro cell-free assay, the addition of recombinant human caspase-8 protein, pre-cleaved by cathepsin D, was followed by caspase-3 activation. Our data therefore indicate that cathepsin D is able to initiate the caspase cascade by direct activation of caspase-8. As cathepsin D is ubiquitously expressed, this may represent a general mechanism to induce apoptosis in a variety of immune and nonimmune cells.
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Mediterranean diet reduces senescence-associated stress in endothelial cells.
Marin, C, Delgado-Lista, J, Ramirez, R, Carracedo, J, Caballero, J, Perez-Martinez, P, Gutierrez-Mariscal, FM, Garcia-Rios, A, Delgado-Casado, N, Cruz-Teno, C, et al
Age (Dordrecht, Netherlands). 2012;(6):1309-16
Abstract
This paper aims to study the effects of the oxidative stress induced by quality and quantity of dietary fat on cellular senescence. Twenty elderly subjects consumed three diets, each for 4 weeks: a saturated fatty acid diet (SFA), a low-fat and high-carbohydrate diet (CHO-ALA), and a Mediterranean diet (MedDiet) enriched in monounsaturated fatty acid following a randomized crossover design. For each diet, we investigated intracellular reactive oxidative species (ROS), cellular apoptosis and telomere length in human umbilical endothelial cells incubated with serum from each patient. MedDiet induced lower intracellular ROS production, cellular apoptosis, and percentage of cell with telomere shortening, compared with the baseline and with SFA and CHO-ALA diets. Dietary fat modulates the oxidative stress in human endothelial cells. MedDiet protects these cells from oxidative stress, prevents cellular senescence and reduces cellular apoptosis.
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A phase 2 study of tasisulam sodium (LY573636 sodium) as second-line treatment for patients with unresectable or metastatic melanoma.
Kirkwood, JM, Gonzalez, R, Reintgen, D, Clingan, PR, McWilliams, RR, de Alwis, DP, Zimmermann, A, Brown, MP, Ilaria, RL, Millward, MJ
Cancer. 2011;(20):4732-9
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Abstract
BACKGROUND Tasisulam sodium (hereafter, tasisulam) is a novel anticancer agent that induces apoptosis through the intrinsic pathway and has antiangiogenic activity in preclinical models. Tasisulam demonstrated activity across a broad range of tumors, including melanoma. The primary objective of this phase 2 study was to determine the objective response rate (ORR) in patients who had received 1 previous systemic chemotherapy for unresectable/metastatic melanoma; secondary objectives were to evaluate the clinical response rate (CRR), progression-free survival (PFS), overall survival (OS), duration of response, safety, and pharmacokinetics. METHODS Tasisulam was administered intravenously on Day 1 of 21-day cycles according to a lean body weight-based dosing algorithm targeting a peak plasma concentration (C(max)) of 420 μg/mL. RESULTS In 68 enrolled patients, the median age was 59 years (range, 26-83 years). No patients had a complete response (CR), 8 patients had a partial response (PR), and 24 patients had stable disease (SD); the ORR (CR + PR) was 11.8%, and the CRR (CR + PR + SD) was 47.1%. The median PFS was 2.6 months, and the median OS was 9.6 months. The predominant treatment-related grade 3/4 toxicity was thrombocytopenia (20.6% of patients). Tasisulam exhibited a biexponential disposition with a predicted distribution half-life of 0.3 hours to 2.8 hours and a median terminal elimination half-life of 10 days (consistent with the turnover of albumin), suggesting that tasisulam is very tightly bound to albumin. CONCLUSIONS Tasisulam administered at a targeted C(max) of 420 μg/mL on Day 1 of 21-day cycles demonstrated activity and tolerable toxicity as second-line treatment in malignant melanoma. These results led to a registration trial in metastatic melanoma.
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Melatonin as a potential tool against oxidative damage and apoptosis in ejaculated human spermatozoa.
Espino, J, Bejarano, I, Ortiz, A, Lozano, GM, García, JF, Pariente, JA, Rodríguez, AB
Fertility and sterility. 2010;(5):1915-7
Abstract
It is assumed somatic cells can die in the apoptotic, the autophagic, or the necrotic way; however, the mechanisms of sperm death are not clear. Here, ejaculated human spermatozoa were evaluated for apoptosis and reactive oxygen species production in the absence or presence of melatonin, and we concluded that melatonin reverses sperm apoptosis due to its free radical scavenging actions.
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Effects of a high daily dose of soy isoflavones on DNA damage, apoptosis, and estrogenic outcomes in healthy postmenopausal women: a phase I clinical trial.
Pop, EA, Fischer, LM, Coan, AD, Gitzinger, M, Nakamura, J, Zeisel, SH
Menopause (New York, N.Y.). 2008;(4 Pt 1):684-92
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Abstract
OBJECTIVE A phase I double-blind clinical trial was conducted to evaluate the effects of a high oral dose of soy isoflavones administered daily for 84 days to healthy postmenopausal women. Principal outcome measures included DNA damage, apoptosis, and changes indicative of estrogenic stimulation. DESIGN After eligibility and equol-producer status were determined, stratified randomization was used to assign women to the isoflavone (active) or placebo group. Of the 30 women who completed the study, 18 were in the active group. DNA damage was assessed via COMET and apurinic/apyrimidinic site assays in lymphocytes. Apoptosis was evaluated via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and activated caspase-3 assays in lymphocytes. Estrogenic/antiestrogenic effects were assessed using a self-report questionnaire and by assaying for estrogen, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin in blood. RESULTS In treated postmenopausal women, there was no indication that high doses of soy isoflavones caused DNA strand breakage, increased apurinic/apyrimidinic sites, or increased apoptosis in peripheral lymphocytes. There were no significant changes in mean values for estrogenic effects or other laboratory measurements. Very few adverse events occurred, and the only drug-related adverse events were mild or grade 1 in severity. CONCLUSIONS Unconjugated soy isoflavones appear to be safe and well tolerated in healthy postmenopausal women at doses of 900 mg/day.
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Survivin down-regulation plays a crucial role in 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor-induced apoptosis in cancer.
Kaneko, R, Tsuji, N, Asanuma, K, Tanabe, H, Kobayashi, D, Watanabe, N
The Journal of biological chemistry. 2007;(27):19273-81
Abstract
3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HRIs) are widely used to reduce serum cholesterol in patients with hypercholesterolemia. Previous studies have shown that HRIs can induce apoptosis in colon cancer cells. In this study, we investigated the mechanisms underlying the apoptosis-inducing effect of HRIs in greater detail. The HRI lovastatin induced apoptosis in the human colon cancer cell line SW480 by blocking the cholesterol synthesis pathway. Immunoblot analysis of antiapoptotic molecules, including survivin, XIAP, cIAP-1, cIAP-2, Bcl-2, and Bcl-X(L), revealed that only survivin expression was decreased by lovastatin. Survivin down-regulation by RNA interference induced apoptosis, and survivin overexpression rendered the cells resistant to lovastatin-induced growth inhibition. These results indicate that survivin down-regulation contributes substantially to the proapoptotic properties of lovastatin. Farnesyl pyrophosphate and geranylgeranyl pyrophosphate, two downstream intermediates in the cholesterol synthesis pathway, simultaneously reversed survivin down-regulation and the blocking of Ras isoprenylation by lovastatin. Ras isoprenylation is important for the activation of Ras-mediated signaling, including the activation of the phosphatidylinositol 3-kinase (PI3-kinase)/Akt pathway. The PI3-kinase inhibitor down-regulated survivin in SW480 cells. In addition, lovastatin blocked Ras activation and Akt phosphorylation. We conclude that survivin down-regulation is crucial in lovastatin-induced apoptosis in cancer cells and that lovastatin decreases survivin expression by inhibiting Ras-mediated PI3-kinase activation via the blocking of Ras isoprenylation.