Mechanism Of Apoptosis Induction Research Articles

Synergistic Effect and Mechanism of Apoptosis Induction by Morphine and the HIV-1gp120V3 Loop in Hippocampal Neurons.

HIV-associated neurocognitive disorders (HAND) are a collective name for neurological disorders associated with HIV-1 infection. The incidence and severity of HAND are increased by concomitant opioid use disorder, such as heroin and morphine abuse. Our previous study showed that the HIV-1 envelope protein gp120 and morphine synergistically induce apoptosis in rat hippocampal neurons. However, the underlying mechanism remains unclear. We hypothesized that morphine and gp120 activated the neuronal apoptosis signaling pathway via their typical membrane receptors. If they shared key signaling molecules, their induction of neuronal apoptosis could be inhibited by blocking these targets. We found that morphine and gp120V3 loop synergistically induced hippocampal neuron apoptosis, mediated by activating the extracellular signal-regulated kinase (ERK) pathway, increasing the intracellular Ca2 + concentration and expression of caspase-, and reducing the mitochondrial membrane potential. The ERK inhibitor PD98509 and the phosphatidylinositol 3-kinase activator IGF-1 blocked this effect. These results indicate that ERK plays a crucial role in the apoptosis of hippocampal neurons in HAND.

From Cell Death to Regeneration: Rebuilding After Injury.

The ability to regrow lost or damaged tissues is widespread, but highly variable among animals. Understanding this variation remains a challenge in regeneration biology. Numerous studies from Hydra to mouse have shown that apoptosis acts as a potent and necessary mechanism in regeneration. Much is known about the involvement of apoptosis during normal development in regulating the number and type of cells in the body. In the context of regeneration, apoptosis also regulates cell number and proliferation in tissue remodeling. Apoptosis acts both early in the process to stimulate regeneration and later to regulate regenerative patterning. Multiple studies indicate that apoptosis acts as a signal to stimulate proliferation within the regenerative tissues, producing the cells needed for full regeneration. The conservation of apoptosis as a regenerative mechanism demonstrated across species highlights its importance and motivates the continued investigation of this important facet of programmed cell death. This review summarizes what is known about the roles of apoptosis during regeneration, and compares regenerative apoptosis with the mechanisms and function of apoptosis in development. Defining the complexity of regenerative apoptosis will contribute to new knowledge and perspectives for understanding mechanisms of apoptosis induction and regulation.

Inhibition of thioredoxin reductase (TrxR) triggers oxidative stress-induced apoptosis in filarial nematode Setaria cervi channelized through ASK-1-p38 mediated caspase activation

Inhibition of an imperative antioxidant enzyme with subsequent death is a victorious and widely accepted strategy to combat various infectious diseases. Among different antioxidant enzymes, thioredoxin reductase (TrxR) is an exclusive one. Studies have revealed that direct inhibition of TrxR by different classes of chemical moieties promptly results in the death of an organism. Especially the structural as well as biochemical modifications of the enzyme upon inhibition project serious threat towards the subject organism. Herein, an attempt was made to inhibit TrxR of filarial species by administering Auranofin, 1 chloro 2,4 dinitrobenzene (CDNB), Curcumin, and a novel carbamo dithioperoxo(thioate) derivative (4a). Our study has revealed that inhibition of TrxR resulted in the induction of the classical CED pathway of apoptosis along with the intrinsic and extrinsic pathways of apoptosis (Caspase mediated) routed through the ASK-1/p38 axis. Druggability analysis of filarial TrxR for the selected compounds was performed in silico through molecular docking studies. Therefore, this study attempts to decipher the mechanism of apoptosis induction following TrxR inhibition. The safety of those four compounds in terms of dose and toxicity was taken under consideration. Thitherto, the mechanism of TrxR mediated initiation of cell death in filarial parasite has remained undercover, and therefore, it is a maiden report on the characterization of apoptosis induction upon TrxR inhibition which will eventually help in generating effective antifilarial drugs in the future.

Retraction Note: Chemopreventive Potential of Resveratrol in Mouse Skin Tumors Through Regulation of Mitochondrial and PI3K/AKT Signaling Pathways.

To investigate the chemopreventive potential of resveratrol, a phytoalexin found in seeds and skin of grapes, berries and peanuts in 7,12 dimethyl benz(a)anthracene (DMBA) induced mouse skin tumorigenesis. Topical treatment of resveratrol was given to the animals 1 h prior to DMBA for 28 weeks. At the end of the study period, the skin tumors were dissected out and western blotting was carried out to examine the regulation of proteins involved in anti-tumorigenesis in response to resveratrol. Chemopreventive properties of resveratrol were reflected by delay in onset of tumorigenesis, reduced cumulative number of tumors, and reduction in tumor volume. Results of the western blotting showed that resveratrol treatment increased the DMBA suppressed p53 and Bax while decreased the expression of Bcl-2 and Survivin. Further, resveratrol supplementation resulted in release of cytochrome C, caspases activation, increase in apoptotic protease-activating factor-1 (Apaf-1) as mechanism of apoptosis induction. Resveratrol was also found to inhibit skin tumorigenesis through regulation of Phosphatidylinositol-3-kinase (PI3K)/ and AKT proteins which are implicated in cancer progression because it stimulates proliferation and suppresses apoptosis. Based on the results we can conclude that resveratrol regulates apoptosis and cell survival in mouse skin tumors as mechanism of chemoprevention hence deserve to be a chemopreventive agent.

TAS4464, a NEDD8-activating enzyme inhibitor, activates both intrinsic and extrinsic apoptotic pathways via c-Myc-mediated regulation in acute myeloid leukemia

TAS4464, a potent, selective small molecule NEDD8-activating enzyme (NAE) inhibitor, leads to inactivation of cullin-RING E3 ubiquitin ligases (CRLs) and consequent accumulations of its substrate proteins. Here, we investigated the antitumor properties and action mechanism of TAS4464 in acute myeloid leukemia (AML). TAS4464 induced apoptotic cell death in various AML cell lines. TAS4464 treatments resulted in the activation of both the caspase-9-mediated intrinsic apoptotic pathway and caspase-8-mediated extrinsic apoptotic pathway in AML cells; combined treatment with inhibitors of these caspases markedly diminished TAS4464-induced apoptosis. In each apoptotic pathway, TAS4464 induced the mRNA transcription of the intrinsic proapoptotic factor NOXA and decreased that of the extrinsic antiapoptotic factor c-FLIP. RNA-sequencing analysis showed that the signaling pathway of the CRL substrate c-Myc was enriched after TAS4464 treatment. Chromatin immunoprecipitation (ChIP) assay revealed that TAS4464-induced c-Myc bound to the PMAIP1 (encoding NOXA) and CFLAR (encoding c-FLIP) promoter regions, and siRNA-mediated c-Myc knockdown neutralized both TAS4464-mediated NOXA induction and c-FLIP downregulation. TAS4464 activated both caspase-8 and caspase-9 along with an increase in NOXA and a decrease in c-FLIP, resulting in complete tumor remission in a human AML xenograft model. These findings suggest that NAE inhibition leads to anti-AML activity via a novel c-Myc-dependent apoptosis induction mechanism.

Abstract 6227: ABT-199 and Bortezomib synergistically induce apoptosis in soft-tissue sarcomas

Abstract Soft-Tissue Sarcomas (STS) are mesenchymal malignancies with high heterogeneity that predominantly affect children and young adults. Despite routinely applied therapy strategies including radiotherapy, surgery and chemotherapy, the five-year survival rate of metastatic STS is only 50 %. Therefore, it is of high importance to focus on possible combinational therapies for the effective treatment of all kinds of STS. For such a therapy we combined the clinically approved BH3-mimetic drug ABT-199 (Venetoclax) with the proteasome inhibitor Bortezomib (Velcade). ABT-199 selectively inhibits the anti-apoptotic protein Bcl-2 whereas the proteasome inhibitor Bortezomib is effective, e.g., in multiple myeloma. Sarcoma cell lines were incubated with ABT-199 and Bortezomib alone or in combination and apoptotic cell death was flow cytometric detected by analysis of mitochondrial membrane potential (TMRM) and exposure of phosphatidyl serine (Annexin V). To elucidate an underlying mechanism for apoptosis induction, we analyzed expression of members of the Bcl-2 family involved in the apoptosis pathway by Western Blotting and performed analogue experiments in knock-out cell lines. Combined treatment with ABT-199 and Bortezomib showed synergistic cell death induction in several sarcoma cell lines including Rhabdomyosarcoma, Leiomyosarcoma and Synovial sarcoma. Loss of mitochondrial membrane potential and Annexin V staining revealed apoptosis as the underlying cell death mechanism. Interestingly, expression of Bok, a homologue of the pore-forming effector proteins Bax and Bak, was increased in response to ABT-199 and Bortezomib. Also, expression was increased for the BH3-only protein Noxa and its anti-apoptotic interaction partner Mcl-1. Knock-out (KO) of effector proteins Bax, Bak or Bok in the sarcoma cell line SW982 reduced apoptosis induction by ABT-199/Bortezomib with the most pronounced reduction in SW982/Bax-KO. Additional shRNA mediated knock-down of Noxa in Bax-KO, Bak-KO or Bok-KO SW982 cells further reduced apoptosis compared to Noxa knock-down alone. ABT-199 and Bortezomib synergistically induce apoptotic cell death in various sarcoma cell lines concomitant with enhanced expression of the Bcl-2 proteins Bok, Noxa and Mcl-1. Hence, we suggest a mechanism in which the simultaneous inhibition of anti-apoptotic Bcl-2 by ABT-199 and the stabilization of pro-apoptotic proteins Bok and/or Noxa shift the equilibrium of BCL-2-proteins towards apoptosis. Experiments in Bax, Bak, Bok, and Noxa deficient SW982 cells indicate that Bax and Noxa are crucial for the observed synergistic effect. based on these results we propose the combined treatment with ABT-199 and Bortezomib as a new and highly promising therapy option for advanced STS. Future efforts, e.g. simultaneous knock-out of relevant Bcl-2 proteins, will unravel the detailed underlying mechanism of the observed synergistic cell death induction by ABT-199 and Bortezomib. Citation Format: Sandra Weller, Alina Muenchow, Walter E. Aulitzky, Hans-Georg Kopp, Frank Essmann. ABT-199 and Bortezomib synergistically induce apoptosis in soft-tissue sarcomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6227.

Abstract 6229: MDM2 inhibitors sensitize testicular cancer models to mTORC1/2 inhibitors and cisplatin

Abstract Testicular cancer (TC) is one of the most common solid tumors in young men that can effectively be treated with cisplatin-based chemotherapy. However, 10% of those wild type p53 expressing TC patients will not survive their disease. The aim of this study was to identify effective combinations with MDM2 inhibitors in TC models. A panel of cisplatin sensitive and -resistant human TC cell lines and TC patient-derived xenograft (PDX) models have been treated with MDM2 inhibitors (Nutlin-3a, RG7388), cisplatin and AKT/mTORC1/2 inhibitors (MK2206, AZD8055 and INK128). Survival, apoptosis, and clonogenic assays were performed. Transcriptional activity of p53 was determined using chromatin immunoprecipitation (CHIP) followed by quantitative PCR of target promoters. Mechanisms of apoptosis induction were studied by measuring mitochondrial priming, siRNA approaches and BH3 mimetics. We found that MDM2 inhibitors sensitized TC cell lines to cisplatin and mTORC1/2 inhibition. Nutlin-3a in combination with cisplatin or AZD8055 treatment induced caspase 3 and PARP cleavage and reduced clonogenic outgrowth. Enriched p53 binding to the promoter regions of known activators of extrinsic and intrinsic apoptosis, FAS, PUMA and NOXA, was observed in response to Nutlin-3a or cisplatin. BH3 profiling of mitochondria and siRNA mediated silencing identified PUMA and NOXA as key pro-apoptotic proteins in TC cell lines. Interestingly, addition of the BH3 mimetics ABT-737 and A-1210477, mimicking PUMA and NOXA respectively, to combination treatments shifted the balance towards apoptosis as well. In vivo experiments showed reduced tumor growth especially in the wild type p53 PDX model TC1 treated with RG7388/cisplatin, which was reflected in p53 activation and increased caspase-3 activity. No potentiating effect of this combination was observed in the p53 wild type PDX model TC4. In conclusion, we have demonstrated that targeting of MDM2 in combination with chemotherapy can be very effective in TC models. Our results warrant further investigation of this drug combination in the treatment of TC. Supported by a grant from the Dutch Cancer Society (RUG 2014-6691) Citation Format: Steven de Jong, Gerda de Vries, Gert Jan Meersma, Albert J.H. Suurmeijer, Marcel A.T.M. van Vugt, Jourik A Gietema. MDM2 inhibitors sensitize testicular cancer models to mTORC1/2 inhibitors and cisplatin [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6229.

Design, synthesis, biological evaluation and molecular docking of new uracil analogs-1,2,4-oxadiazole hybrids as potential anticancer agents

A new series of uracil analogues-1,2,4-oxadiazole hybrid derivatives were synthesized by a new, simple, and efficient method using for the first time HAP-SO3H as an heterogenous acid catalyst for the condensation and cyclization between amidoxime and aldehyde. The new derivatives were characterized by HRMS, FT-IR, 1H NMR, and 13C NMR spectroscopy techniques. The synthesized 1,2,4-oxadiazole hybrids were evaluated for their cytotoxic activity in five human cancer cell lines: melanoma (A-375), fibrosarcoma (HT-1080), breast (MCF-7 and MDA-MB-231), and lung carcinoma (A-549). Data showed that compounds 22 and 23 were potent cytotoxic agents against HT-1080 and MFC-7 cells with IC50 inferior to 1 µM. The possible mechanism of apoptosis induction by the derivatives was investigated using Annexin V staining, caspase-3/7 activity, mitochondrial membrane potential measurement, and analysis cell cycle progression. The compound 22 induced apoptosis through caspase-3/7 activation and S-phase arrest in HT-1080 and A549 cells. The molecular docking showed that compound 22 activated the caspase-3 by forming a stable protein-ligand complex.

Novel cyclometalated Ru(II) complexes containing isoquinoline ligands: Synthesis, characterization, cellular uptake and in vitro cytotoxicity

Two novel cyclometalated Ru(II) complexes containing isoquinoline ligand, [Ru(bpy)2(1-Ph-IQ)](PF6), (bpy = 2,2′-bipyridine; 1-Ph-IQ = 1-phenylisoquinoline; RuIQ-1) and [Ru(phen)2(1-Ph-IQ)](PF6) (phen = 1,10-phenanthroline; RuIQ-2) were found to show high cytotoxic activity against NCI–H460, A549, HeLa and MCF-7 cell lines. Notably, both of them exhibited IC50 values that were an order of magnitude lower than those of clinical cisplatin and two structurally similar Ru(II)-isoquinoline complexes [Ru(bpy)2(1-Py-IQ)](PF6)2 (Ru3) and [Ru(phen)2(1-Py-IQ)](PF6)2 (Ru4) (1-Py-IQ = 1-pyridine-2-yl). The cellular uptake and intracellular localization displayed that the two cyclometalated Ru(II) complexes entered NCI–H460 cancer cells dominantly via endocytosis pathway, and preferentially distributed in the nucleus. Further investigations on the apoptosis-inducing mechanisms of RuIQ-1 and RuIQ-2 revealed that the two complexes could cause S, G2/M double-cycle arrest by regulating cell cycle related proteins. The two complexes also could reduce the mitochondrial membrane potential (MMP), promote the generation of intracellular ROS and trigger DNA damage, and then lead to apoptosis-mediated cell death. More importantly, RuIQ-2 exhibits low toxicity both towards normal HBE cells in vitro and zebrafish embryos in vivo. Accordingly, the developed complexes hold great potential to be developed as novel therapeutics for effective and low-toxic cancer treatment.

Abstract B061: Effect of artonin E on apoptosis cell death induction in colon cancer cell

Abstract Colon cancer is the most common cause of cancer death in both men and women around the world. The three human RAS genes (KRAS, NRAS and HRAS) are the most frequently mutated oncogenes in human cancer including pancreatic, lung and colon cancers. In particular, KRAS mutated gene prevalently found in pancreas, lung and colon cancer [1]. In colorectal cancer patients, approximately 35-45% mutated KRAS oncogene was reported. The downstream of KRAS associated with survival signaling pathways including Raf/Mek/MAPK and PI3K/Akt [2]. Normally, cancer cell escape death induction by upregulation of Raf/Mek/MAPK and PI3K/Akt activity. Thus, inhibition of Raf/Mek/MAPK and PI3K/Akt signaling pathway is necessary. Nowadays, treatment of colon cancer is quite limited due to the high cost and side effects, therefore, bioactive compound therapy might be the choice for development of colon cancer treatment. In this study, we investigate the effect of artonin E on apoptosis induction in colon cancer HCT116 cells. Nuclear morphological changes and the loss of mitochondrial membrane potential, characteristics of apoptosis induction were determined by Hoechst 33342 staining and JC-1 staining, respectively. Mediator proteins that associated with apoptosis induction and signaling molecules were determined by Western blot analysis. Our results indicated that artonin E induced apoptotic bodies and loss of mitochondrial membrane potential in HCT116 treated cells. In addition, artonin E showed upregulation of cleave-caspase-7 (active form) and cleave-PARP (inactive form), mediator of apoptosis induction, in HCT116 cells. Moreover, artonin E reduced Akt and increased p-ERK1/2 expression in HCT116 cells. This data correlated with previous study by Tangchirakhaphan et al and Bee-Jen Tan et al, that ERK1/2 could activate caspase and pro-apoptotic protein in Bcl-2 family. Moreover, ERK1/2 could deactivate Akt signaling pathway leading to apoptosis induction [3,4]. Our study indicated that artonin E induced apoptosis cell death through p-ERK1/2 upregulation and may be used as a potential therapeutic candidate in the future. Keywords: Artonin E, Apoptosis, Colon cancer, KRAS [1] Cox AD, Fesik SW, Kimmelman AC, Luo J, Der CJ. Drugging the undruggable RAS: Mission possible? Nat Rev Drug Discov. 2014;13(11):828-51. [2] Eser S, Schnieke A, Schneider G, Saur D. Oncogenic KRAS signalling in pancreatic cancer. Br J Cancer. 2014;111(5):817-22. [3] Tangchirakhaphan S, Innajak S, Nilwarangkoon S, Tanjapatkul N, Mahabusrakum W, Watanapokasin R. Mechanism of apoptosis induction associated with ERK1/2 upregulation via goniothalamin in melanoma cells. Exp Ther Med. 2018;15(3):3052-8. [4] Tan BJ, Chiu GN. Role of oxidative stress, endoplasmic reticulum stress and ERK activation in triptolide-induced apoptosis. Int J Oncol. 2013;42(5):1605-12. Citation Format: Supichaya Nimnuan-ngam, Kanyaluck Yangnok, Sukanda Innajak, Ramida Watanapokasin. Effect of artonin E on apoptosis cell death induction in colon cancer cell [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B061.

Molecular Insights Into Di(2-Picolyl) Amine-Induced Cytotoxicity and Apoptosis in Human Kidney (HEK293) Cells.

Di(2-picolyl) amine (DPA) is a pyridine derivative known to chelate metal ions and thus has potential anticancer properties; however, its effect on normal cells remains unchartered necessitating further research. This study, therefore, investigated the mechanistic effects of DPA-induced cytotoxicity and apoptosis in the HEK293 cell line. Methods required that an half the maximum inhibition concentration (IC50) was derived using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Analyses aimed to assess oxidative stress, membrane damage, and DNA fragmentation by means of biochemical assays were performed. Luminometry analysis was carried out to understand the mechanism of apoptosis induction by determining the levels of adenosine triphosphate (ATP) and the activities of caspase-8, -9, and -3/7. Western blotting was used to ascertain the expression of apoptotic and stress-related proteins. An IC50 of 1,079 µM DPA was obtained. Antioxidant effect correlated with a minimum increase in reactive oxygen species induced lipid peroxidation. The increase in initiator caspase-8 and -9 and executioner caspase-3/7 activities by DPA-induced apoptosis albeit prompting a decline in the levels of ATP. Furthermore, DPA brought about the following consequences on HEK293 cells: markedly elevated tail lengths of the comets, poly (ADP-ribose) polymerase 1 cleavage, and apoptotic body formation observed in the late stages. The cytotoxic effects of DPA in HEK293 cells may be mediated by induction of apoptosis via the caspase-dependent mechanism.

Molecular mechanisms of apoptosis induction in K562 and KG1a leukemia cells by a water-soluble copper(II) thiosemicarbazone complex

Thiosemicarbazones (TSCs) and their metal complexes exhibit pronounced and selective cytotoxic potential against a broad span of cancers. Here, we assessed the anti-cancer activity of a water-soluble copper(II) complex of thiosemicarbazone (Cu-TSC) against two cancer cell lines of human leukemia. Our analysis revealed that Cu-TSC treatment results in a time and dose-dependent growth inhibition in K562 and KG1a cells while sparing normal human fibroblast (HFF2) cells. The IC50 values for the Cu-TSC treatment were measured to be 21.7 ± 1.5µM and 50.25 ± 2.5µM for K562 and KG1a cells, respectively. Cell cycle analysis indicated that Cu-TSC induces the accumulation of cells in the sub-G1 fraction as well as the reversible arrest in G0/G1 and G2/M phases in K562 and KG1a cells, respectively. Furthermore, the occurrence of apoptosis as the prime mode of cell death was verified through apoptotic body formation, phosphatidylserine externalization, and caspase-3 activation. Additionally, the real-time quantitative PCR analysis revealed that Cu-TSC triggers apoptosis in both cell lines via the upregulation of caspases-8, -9, and the changing of Bax/Bcl2 ratio. Finally, flow cytometric analysis confirmed that Cu-TSC treatment causes the enhancement of reactive oxygen species formation in both K562 and KG1a cells. Altogether, these findings suggest that Cu-TSC is a promising inducer of apoptosis in leukemia cells and carries potential as an anti-cancer compound.

In Vitro Oncolytic activity of non-virulent Newcastle Disease Virus LaSota Strain against Mouse mammary adenocarcinoma

Newcastle disease virus (NDV) is a wide-spectrum anti-tumor agent. The oncolytic selectivity of NDV, a family of Paramyxoviridae, depends on the differential type of inducing different death pathways. This work was conducted to further understand the oncolytic effect of LaSota strain. A mouse breast cancer model (Murine mammary adenocarcinoma cell line AMN3) was used in this study. Methyl Thiazolyl Tetrazolium (MTT) viability assay tested different NDV multiplicity of infection (MOI) values on mouse mammary adenocarcinoma cells incubated for 72 hours post-infection. The IC50 values and anti-tumor activity of LaSota strain against AMN3 cell line were determined. Following Hematoxylin and Eosin Stain, we examined the morphological modifications of IC50 along with 10 MOI values of NDV. The induction of NDV apoptosis in AMN3 cells was investigated using the technique of staining acridine orange and propidium iodide (AO / PI). Immunocytochemistry assay was performed using anti-NDV mAbs and caspases 8 and 9 to study NDV replication and apoptosis induction mechanisms. The lentogenic LaSota NDV strain, a live vaccine, demonstrated the oncolytic effect on mammary cancer cells of the AMN3 mouse and showed that LaSota strain triggered a dose-dependent increase in infected cells’ apoptosis relative to untreated mammary cancer cells. The immunocytochemistry study showed that NDV infected cells were positive for virus infection and that caspase9 in mouse mammary cancer cells after LaSota strain infection was significantly enhanced compared to caspase 8. In conclusions, NDV LaSota strain had oncolytic effects by destroying tumor cells and triggering the intrinsic apoptosis pathways in mouse mammary cancer cells. However, the mechanisms of the in vivo anti-tumor activity need to be better understood.

Y-box protein 1 promotes hypoxia/reoxygenation- or ischemia/reperfusion-induced cardiomyocyte apoptosis via SHP-1-dependent STAT3 inactivation.

Cardiomyocyte apoptosis induced by hypoxia and ischemia plays important roles in heart dysfunction after acute myocardial infarction (AMI). However, the mechanism of apoptosis induction remains unclear. A previous study reported that Y-box protein 1 (YB1) is upregulated after myocardial hypoxia/reoxygenation or ischemia/reperfusion (H/R or I/R, respectively) injury; however, whether YB1 is associated with H/R-induced cardiomyocyte apoptosis is completely unknown. In the present study, we investigated the roles of YB1 in H/R-induced cardiomyocyte apoptosis and the possible underlying molecular mechanisms. In vitro, H/R treatment upregulated the YB1 expression in H9C2 cells, whereas YB1 knockdown inhibited H/R-induced cardiomyocyte apoptosis and induced H9C2 cell proliferation via Src homology region 2 domain-containing phosphatase 1 (SHP-1)-mediated activation of signal transducer and activator of transcription 3 (STAT3). In vivo, YB1 knockdown ameliorated AMI, reducing infarct size, cardiomyocyte apoptosis,and oxidative stress, via SHP-1-mediated inactivation of STAT3. Additionally, YB1 knockdown inhibited H/R- or I/R-induced oxidative stress in vitro and in vivo. H/R and I/R increase YB1 expression, and YB1 knockdown ameliorates AMI injury via SHP-1-dependent STAT3 inactivation.

Heparanase and Type 1 Diabetes.

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing beta cells in pancreatic islets. The degradation of the glycosaminoglycan heparan sulfate (HS) by the endo-β-D-glycosidase heparanase plays a critical role in multiple stages of the disease process. Heparanase aids (i) migration of inflammatory leukocytes from the vasculature to the islets, (ii) intra-islet invasion by insulitis leukocytes, and (iii) selective destruction of beta cells. These disease stages are marked by the solubilization of HS in the subendothelial basement membrane (BM), HS breakdown in the peri-islet BM, and the degradation of HS inside beta cells, respectively. Significantly, healthy islet beta cells are enriched in highly sulfated HS which is essential for their viability, protection from damage by reactive oxygen species (ROS), beta cell function and differentiation. Consequently, mouse and human beta cells but not glucagon-producing alpha cells (which contain less-sulfated HS) are exquisitely vulnerable to heparanase-mediated damage. In vitro, the death of HS-depleted mouse and human beta cells can be prevented by HS replacement using highly sulfated HS mimetics or analogues. T1D progression in NOD mice and recent-onset T1D in humans correlate with increased expression of heparanase by circulating leukocytes of myeloid origin and heparanase-expressing insulitis leukocytes. Treatment of NOD mice with the heparanase inhibitor and HS replacer, PI-88, significantly reduced T1D incidence by 50%, impaired the development of insulitis and preserved beta cell HS. These outcomes identified heparanase as a novel destructive tool in T1D, distinct from the conventional cytotoxic and apoptosis-inducing mechanisms of autoreactive T cells. In contrast to exogenous catalytically active heparanase, endogenous heparanase may function in HS homeostasis, gene expression and insulin secretion in normal beta cells and immune gene expression in leukocytes. In established diabetes, the interplay between hyperglycemia, local inflammatory cells (e.g. macrophages) and heparanase contributes to secondary micro- and macro-vascular disease. We have identified dual activity heparanase inhibitors/HS replacers as a novel class of therapeutic for preventing T1D progression and potentially for mitigating secondary vascular disease that develops with long-term T1D.

Molecular Detection of Cordycepin-Induced HeLa Cell Apoptosis with Surface-Enhanced Raman Spectroscopy

Cordycepin, extracted from the medicinal mushroom Cordyceps militaris, was shown to induce cancer cell apoptosis. Yet its anticancer function was limitedly evaluated, and the mechanism was not entirely elucidated. In this study, we demonstrated the effectiveness of cordycepin in inducing apoptosis in HeLa cells and investigated its apoptosis-inducing mechanism through label-free surface-enhanced Raman spectroscopy (SERS). SERS spectral changes revealed detailed molecular changes in both early and late stages of apoptosis. Importantly, SERS characteristic peaks at 805 and 1438 cm−1, which were assigned to RNA, continued to decrease significantly from early to late apoptosis stages. It indicated that cordycepin induced HeLa cell apoptosis mainly through interfering with RNA production, potentially by restraining the translation of RNA encoding ribosomal proteins. Meanwhile, apoptotic cells and their apoptosis stage could be easily differentiated by SERS-based principal component analysis (PCA). Furthermore, the morphological changes of early and late-stage apoptotic cells were illustrated by differential interference contrast and fluorescence microscopic imaging. Therefore, the natural ingredient, cordycepin, could serve as a promising anticancer candidate. Our biological model of cell apoptosis in vitro, the non-invasive and rapid SERS technique, combined with PCA analysis, could be a powerful tool in the investigation of cell apoptosis mechanisms and anticancer drug screening.

In Vitro and in Vivo antitumor activity and the mechanism of siphonodictyal B in human colon cancer cells.

Liphagal, isolated from the marine sponge Aka coralliphaga, exhibits phosphatidylinositol 3‐kinase alpha (PI3Kα) inhibitory activity and cytotoxic effects in human cancer cells. Siphonodictyal B, the biogenetic precursor of liphagal, also has PI3K inhibitory activity. However, its cytotoxic or antitumor activities have not been evaluated. In this study, we demonstrated that siphonodictyal B inhibits several kinases such as CDK4/6, CDK7, and PIM2 in addition to PI3K in vitro and that siphonodictyal B exhibits more potent cytotoxic effects than liphagal against human colon cancer cell lines. Furthermore, treatment with siphonodictyal B resulted in increased PARP cleavage, a larger sub‐G1 fraction, and a larger annexin V‐positive cell population, all of which are indicative of apoptosis induction. As a mechanism of apoptosis induction, we found that siphonodictyal B activates the p38 MAPK pathway, leading the upregulation of proapoptotic factors. Moreover, siphonodictyal B increased ROS levels, thus promoting p38 MAPK pathway activation. NAC, an ROS scavenger, almost completely reversed both the cytotoxic and p38 MAPK pathway‐activating effects of siphonodictyal B. These results indicate that the p38 MAPK pathway might be involved downstream of ROS signaling as part of the mechanism of siphonodictyal B‐induced apoptosis. Finally, siphonodictyal B displayed antitumor effects in a human colon cancer xenograft mouse model and increased p38 phosphorylation in tumor tissue. These results suggest that siphonodictyal B could serve as the basis of a novel anticancer drug.

Potential of Teucrium chamaedrys L. to modulate apoptosis and biotransformation in colorectal carcinoma cells

Ethnopharmacological relevanceTeucrum chamaedrys L. is one of the known medicinal plants, useful for treatment of various health problems, especially digestive. In this study, we investigated methanol, ethyl-acetate and acetone extracts of T. chamaedrys in respect to their anticancer properties in SW480 colorectal cancer cells. Materials and methodsCytotoxicity and proapoptotic potential were assessed by MTT cell viability assay and AO/EB double staining. Molecular mechanisms of induced apoptosis were determined by monitoring Fas receptor protein expression through immunofluorescence, Caspase 8 and 9 activity, as well as concentrations of O2.- spectrophotometrically. Additionally, mRNA expression of biotransformation enzymes (CYP1A1, CYP1B1, GSTP1) and membrane transporters (MRP1 and MRP2) involved in drug resistance were investigated by qPCR method. Qualitative analysis of individual phenolic compounds was performed by reversed phase HPLC-MS analysis. ResultsMethanol extract shows the best cytotoxicity and selectivity compared to ethyl-acetate and acetone extracts, mainly causing apoptosis of SW480 cells, without affecting normal HaCaT keratinocytes. The increased expression of Fas receptor protein and caspase 8 activity indicate that the death receptor-mediated pathway plays a crucial role in the observed apoptosis. The increased caspase 9 activity and O2.- concentration suggest that mitochondria are also involved in the apoptosis. T. chamaedrys methanol extract inhibits mRNA expression of CYP1A1, CYP1B1, GSTP1, MRP1 and MRP2 in SW480 cells. ConclusionsInduction of apoptosis and inhibition of CYP1A1, CYP1B1, GSTP1, MRP1 and MRP2 mRNA expression implies that T. chamaedrys can serve as a valuable source of bioactive compounds as dietary supplements or selective anticancer agents, with the ability to induce apoptosis and modulate drug resistance in colorectal cancer cells.

Adapalene suppressed the proliferation of melanoma cells by S-phase arrest and subsequent apoptosis via induction of DNA damage

Malignant melanoma was the leading cause of mortality among the skin-associated cancer owing to its highly metastatic feature, increasing incidence and drug resistance requirement. Retinoids played important roles in the treatment of cancer via the activation of retinoid acid receptor (RAR) or retinoid X receptor (RXR). Our present study showed that the third-generation retinoid adapalene exhibited strong inhibitory effects on the proliferation of melanoma cells than other retinoids, such as all-trans-retinoic acid (ATRA), isotretinoin, acitretin and bexarotene, and adapalene exerted significant inhibitory effects on the colony formation of melanoma cells. Further study confirmed that adapalene treatment triggered dramatic S phase arrest and apoptosis, and S phase arrest was the potential mechanism of apoptosis induction. In addition, adapalene treatment dramatically regulated the expression of S phase-related protein, and increased the protein level of DNA damage marker，which were consistent with the results of the induction of the tail moment in comet assays. Meanwhile, DNA damage response was activated and the DNA repair pathway was simultaneously inhibited by adapalene treatment, which might furtherly potentiate S phase arrest and subsequent apoptosis. Taken together, these results showed that adapalene exhibited strong anti-cancer activity, and might be a candidate agent for the clinical treatment of melanoma.

Areca nut extract demonstrated apoptosis-inducing mechanism by increased caspase-3 activities on oral squamous cell carcinoma

Background: Oral squamous cell carcinoma is a neoplasm of keratinocyte cells of oral mucosa epithelium that can potentially spread through lymphatic tissue or blood vessel. Although areca nut is one of the plants with a risk of inducing that cancer, areca nut is believed to have high antioxidant properties. Due to the current interest in the apoptosis effects from areca nut for oral cancer treatment, we investigated its ability to induce apoptosis and caspase-3 activity in oral cancer cell lines: HSC-2 and HSC-3. Methods: We examined the effect of areca nut on apoptosis and caspase-3 activity in HSC-2 and HSC-3 cells. Flow cytometry was conducted for the quantification of the cells that were apoptotic and expressing the caspase-3 enzyme for 24 and 48 hours. Results: Areca nut induced a significant increase (p<0.01) in late apoptosis of HSC-2 cells and mostly occurred over 48 hours. The study also found that in HSC-3, there were significant increases (p<0.01) the percentage of cells in early apoptosis after 24 hours and late apoptosis at 48 hours. Caspase-3 activity increased after 24 and 48 hours of areca nut exposure in both cells. Conclusions: The study showed that areca nut could be considered as a potential anticancer agent through its capability in inducing a caspase-dependent apoptosis.