Intrinsic Apoptosis Signaling Pathways Research Articles

Discovery of PRMT3 Degrader for the Treatment of Acute Leukemia.

Protein arginine methyltransferase 3 (PRMT3) plays an important role in gene regulation and a variety of cellular functions, thus, being a long sought-after therapeutic target for human cancers. Although a few PRMT3 inhibitors are developed to prevent the catalytic activity of PRMT3, there is little success in removing the cellular levels of PRMT3-deposited ω-NG,NG-asymmetric dimethylarginine (ADMA) with small molecules. Moreover, the non-enzymatic functions of PRMT3 remain required to be clarified. Here, the development of a first-in-class MDM2-based PRMT3-targeted Proteolysis Targeting Chimeras (PROTACs) 11 that selectively reduced both PRMT3 protein and ADMA is reported. Importantly, 11 inhibited acute leukemia cell growth and is more effective than PRMT3 inhibitor SGC707. Mechanism study shows that 11 induced global gene expression changes, including the activation of intrinsic apoptosis and endoplasmic reticulum stress signaling pathways, and the downregulation of E2F, MYC, oxidative phosphorylation pathways. Significantly, the combination of 11 and glycolysis inhibitor 2-DG has a notable synergistic antiproliferative effect by further reducing ATP production and inducing intrinsic apoptosis, thus further highlighting the potential therapeutic value of targeted PRMT3 degradation. These data clearly demonstrated that degrader 11 is a powerful chemical tool for investigating PRMT3 protein functions.

Cytoplasmic TP53INP2 acts as an apoptosis partner in TRAIL treatment: the synergistic effect of TRAIL with venetoclax in TP53INP2-positive acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is a hematopoietic malignancy with poor outcomes, especially in older AML patients. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered a promising anticancer drug because it selectively induces the extrinsic apoptosis of tumor cells without affecting normal cells. However, clinical trials have shown that the responses of patients to TRAIL are significantly heterogeneous. It is necessary to explore predictable biomarkers for the preselection of AML patients with better responsiveness to TRAIL. Here, we investigated the critical role of tumor protein p53 inducible nuclear protein 2 (TP53INP2) in the AML cell response to TRAIL treatment.MethodsFirst, the relationship between TP53INP2 and the sensitivity of AML cells to TRAIL was determined by bioinformatics analysis of Cancer Cell Line Encyclopedia datasets, Cell Counting Kit-8 assays, flow cytometry (FCM) and cell line-derived xenograft (CDX) mouse models. Second, the mechanisms by which TP53INP2 participates in the response to TRAIL were analyzed by Western blot, ubiquitination, coimmunoprecipitation and immunofluorescence assays. Finally, the effect of TRAIL alone or in combination with the BCL-2 inhibitor venetoclax (VEN) on cell survival was explored using colony formation and FCM assays, and the effect on leukemogenesis was further investigated in a patient-derived xenograft (PDX) mouse model.ResultsAML cells with high TP53INP2 expression were more sensitive to TRAIL in vitro and in vivo. Gain- and loss-of-function studies demonstrated that TP53INP2 significantly enhanced TRAIL-induced apoptosis, especially in AML cells with nucleophosmin 1 (NPM1) mutations. Mechanistically, cytoplasmic TP53INP2 maintained by mutant NPM1 functions as a scaffold bridging the ubiquitin ligase TRAF6 to caspase-8 (CASP 8), thereby promoting the ubiquitination and activation of the CASP 8 pathway. More importantly, simultaneously stimulating extrinsic and intrinsic apoptosis signaling pathways with TRAIL and VEN showed strong synergistic antileukemic activity in AML cells with high levels of TP53INP2.ConclusionOur findings revealed that TP53INP2 is a predictor of responsiveness to TRAIL treatment and supported a potentially individualized therapeutic strategy for TP53INP2-positive AML patients.

Repurposing of Antifungal Drug Flucytosine/Flucytosine Cocrystals for Anticancer Activity against Prostate Cancer Targeting Apoptosis and Inflammatory Signaling Pathways.

This study aimed to repurpose the antifungal drug flucytosine (FCN) for anticancer activity together with cocrystals of nutraceutical coformers sinapic acid (SNP) and syringic acid (SYA). The cocrystal screening experiments with SNP resulted in three cocrystal hydrate forms in which two are polymorphs, namely, FCN-SNP F-I and FCN-SNP F-II, and the third one with different stoichiometry in the asymmetric unit (1:2:1 ratio of FCN:SNP:H2O, FCN-SNP F-III). Cocrystallization with SYA resulted in two hydrated cocrystal polymorphs, namely, FCN-SYA F-I and FCN-SYA F-II. All the cocrystal polymorphs were obtained concomitantly during the slow evaporation method, and one of the polymorphs of each system was produced in bulk by the slurry method. The interaction energy and lattice energies of all cocrystal polymorphs were established using solid-state DFT calculations, and the outcomes correlated with the experimental results. Further, the in vitro cytotoxic activity of the cocrystals was determined against DU145 prostate cancer and the results showed that the FCN-based cocrystals (FCN-SNP F-III and FCN-SYA F-I) have excellent growth inhibitory activity at lower concentrations compared with parent FCN molecules. The prepared cocrystals induce apoptosis by generating oxidative stress and causing nuclear damage in prostate cancer cells. The Western blot analysis also depicted that the cocrystals downregulate the inflammatory markers such as NLRP3 and caspase-1 and upregulate the intrinsic apoptosis signaling pathway marker proteins, such as Bax, p53, and caspase-3. These findings suggest that the antifungal drug FCN can be repurposed for anticancer activity.

Research and Development Progression of Oridonin for Hematological Malignancies Therapy.

Oridonin is a tetracyclic diterpenoid compound extracted from the medicinal herb Isodon and related species. Since 1976, studies have reported the significant anti-tumor activity of oridonin in vivo. Recently, an increasing number of studies have confirmed the anti-tumor effects of oridonin in various types of cancers, and its effect on hematological malignancies stands out. Herein, we have systematically reviewed the anti-- tumor effects of oridonin and its specific mechanisms in hematological malignancies, including the regulation of cancer proteins, activation of intrinsic and extrinsic apoptosis signaling pathways, accumulation of reactive oxygen species (ROS), modulation of chaperone proteins and miRNA expression, combination therapy with chemotherapeutic drugs, and the development of its derivatives. Taken together, oridonin exhibits multiple anti-tumor activities and serves as a multi-target agent, making it worthy of further investigation.

Atherogenic Activation of Human Vascular Smooth Muscle Cells by Monosodium Urate Crystals

Gout is strongly associated with atherosclerosis and other cardiovascular comorbidities. Furthermore, sites of extra-articular monosodium urate (MSU) crystal deposits in gout can include heart valves and atherosclerotic artery plaques, but with unclear effects therein. Hence, we seminally explored cultured vascular smooth muscle cell (VSMC) responsiveness to MSU crystals. To limit confounding effects, we cultured human aortic VSMCs under serum-free conditions to assess MSU crystal effects on VSMC differentiation and function, differentially expressed genes (DEGs) via RNA sequencing, and selected atherogenic changes in cytokines and the lipidome. MSU crystals induced p38 phosphorylation, IL-6, and VSMC vacuolization with dysregulated autophagy. MSU-crystal-induced DEGs included decreased late-stage autophagosome maturation mediator GABARAPL1, decreased physiologic VSMC differentiation regulators (LMOD1 and SYNPO2), increased ATF4, CHOP, and the intrinsic apoptosis signaling pathway in response to ER stress, and neointimal atherogenic nuclear receptors (NR4A1 and NR4A3). MSU crystals alone increased the levels of cholesterol biosynthetic intermediates 14-demethyl-lanosterol (14-DML), desmosterol, and zymosterol. Adding MSU crystals increased oxidized LDL’s capacity to increase intracellular 27-OH cholesterol, and MSU crystals and oxidized LDL synergistically induced a marked release of arachidonate. In conclusion, MSU crystals deposited in arterial media and neointima have the potential to dysregulate VSMC differentiation and proteostasis, and to induce further atherogenic effects, which include enhanced VSMC loading of oxidized cholesterol intermediates and release of IL-6 and arachidonic acid (AA).

Controlled synthesis of zinc oxide nanoparticles through flame spray pyrolysis and evaluation of their anticancer effects against gastric cancer cell

Although zinc oxide nanoparticles (ZnO NPs) have demonstrated promising anticancer activity, their therapeutic performances are frequently influenced by the synthesis routes and associated distinct physicochemical characteristics. Herein, ZnO NPs were synthesized through a cost-effective flame spray pyrolysis-assisted approach and their selective anticancer effects and underlying intrinsic apoptosis signaling pathway in human gastric carcinoma cell line (AGS) were examined. Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and dynamic light scattering (DLS) investigations were used to characterize the synthesized ZnO NPs. Afterwards, AGS and normal fibroblast cells (L-929) were treated with various concentrations of ZnO NPs, and cell proliferation was examined by the MTT assay to determine the IC50 concentration of NPs. Furthermore, the quantification of ROS and apoptosis was done by fluorometer and flow cytometry assays. Additionally, superoxide dismutase (SOD) and catalase (CAT) activity assays were performed to evaluate the oxidative stress-induced cytotoxicity mediated by ZnO NPs against AGS cells. Moreover, caspase-3/-8/-9 activity and mitochondrial membrane potential (MMP) assays were done. Finally, the expression levels of p53, Bax, Bcl-2, caspase-9/-8/-3, and cytochrome c were assessed by quantitative real time PCR and western blot analyses to explore the probable mitochondrial apoptosis signaling pathway induced by ZnO NPs in AGS cells. The results showed that ZnO NPs with an absorption maximum at 350 nm, an average size of 70 nm, a hydrodynamic radius of 92.89 nm, and a zeta potential of −43.13 mV potentially and selectively inhibited the proliferation of AGS cells in comparison with L-929 cells through a remarkable increase in the production of ROS, induction of apoptosis, reduction of SOD and CAT activity, activation of caspase-9/-3, and MMP disruption. Moreover, ZnO NPs triggered up-regulation of p53, Bax, caspase-9/-3, cytochrome c and down-regulation of Bcl-2 at mRNA and protein levels. This study suggests that synthesized ZnO NPs through flame spray pyrolysis can induce selective anticancer effects against gastric cancer cells via intrinsic apoptosis signaling pathway.

Unveiling nature's potential weapon: Magnolol's role in combating bladder cancer by upregulating the miR-124 and inactivating PKC-δ/ERK axis

BackgroundBladder cancer (BC) is a challenging disease to manage. Researchers have been investigating the potential of magnolol, a compound derived from Magnolia officinalis, as an anti-cancer agent. However, the exact regulatory mechanism of magnolol and its impact on the NF-κB signaling pathway in BC remain unclear. MaterialsTo comprehensively evaluate its therapeutic potential, the researchers conducted a series of experiments using BC cell lines (TSGH8301, T24, and MB49) and in vivo animal models. ResultsThe results of the study demonstrated that magnolol exhibits cytotoxic effects on BC cells by activating both the extrinsic and intrinsic apoptosis signaling pathways. Additionally, the expression of anti-apoptotic genes was downregulated by magnolol treatment. The researchers also uncovered the regulatory role of PKCδ/ERK and miR-124-3p in the NF-κB pathway, which may be influenced by magnolol. Treatment with magnolol led to the inactivation of PKCδ/ERK and an increase in miR-124-3p expression, effectively inhibiting NF-κB-mediated progression of BC. Importantly, the administration of magnolol did not result in significant toxicity in normal tissues, highlighting its potential as a safe adjunctive therapy with minimal adverse effects. ConclusionThese findings position magnolol as a promising therapeutic agent for the treatment of BC. By activating apoptosis signaling pathways and inhibiting NF-κB pathway through the upregulation of miR-124-3p and downregulation of PKCδ/ERK activation, magnolol holds promise for suppressing tumor progression and improving patient outcomes in BC. Further research and clinical trials are warranted to explore the full potential of magnolol in the future.

Knockdown of LINC01087 inhibits gastric cancer malignant behavior by regulating the miR-135a-5p/CAAP1 axis.

Long noncoding RNAs play important roles in the occurrence and development of many malignant cancers. This study focuses on the effects of LINC01087 on gastric cancer and its underlying mechanism. In the present study, LINC01087 and CAAP1 were found to be upregulated, and miR-135a-5p was diminished in gastric cancer specimens and cells. Inhibition of LINC01087 resulted in cell proliferation inhibition and induced cell apoptosis through the intrinsic apoptosis signaling pathway, as evidenced by the activation of caspase-3 and caspase-9. An investigation of the signaling pathway revealed that the effects on proliferation and apoptosis following LINC01087 knockdown were mediated by suppression of CAAP1. Furthermore, application of a miR-135a-5p inhibitor or overexpression of CAAP1 could attenuate the apoptotic effect achieved by LINC01087 inhibition, confirming the involvement of miR-135a-5p/CAAP1 signaling in the occurrence of gastric cancer. In conclusion, the LINC01087/miR-135a-5p/CAAP1 axis modulates gastric cancer tumorigenesis and pathogenesis and presents new insight into gastric cancer targeted therapy.

Activity of eftozanermin alfa plus venetoclax in preclinical models and patients with acute myeloid leukemia

AbstractActivation of apoptosis in malignant cells is an established strategy for controlling cancer and is potentially curative. To assess the impact of concurrently inducing the extrinsic and intrinsic apoptosis-signaling pathways in acute myeloid leukemia (AML), we evaluated activity of the TRAIL receptor agonistic fusion protein eftozanermin alfa (eftoza; ABBV-621) in combination with the B-cell lymphoma protein-2 selective inhibitor venetoclax in preclinical models and human patients. Simultaneously stimulating intrinsic and extrinsic apoptosis-signaling pathways with venetoclax and eftoza, respectively, enhanced their activities in AML cell lines and patient-derived ex vivo/in vivo models. Eftoza activity alone or plus venetoclax required death receptor 4/5 (DR4/DR5) expression on the plasma membrane but was independent of TP53 or FLT3-ITD status. The safety/tolerability of eftoza as monotherapy and in combination with venetoclax was demonstrated in patients with relapsed/refractory AML in a phase 1 clinical trial. Treatment-related adverse events were reported in 2 of 4 (50%) patients treated with eftoza monotherapy and 18 of 23 (78%) treated with eftoza plus venetoclax. An overall response rate of 30% (7/23; 4 complete responses [CRs], 2 CRs with incomplete hematologic recovery, and 1 morphologic leukemia-free state) was reported in patients who received treatment with eftoza plus venetoclax and 67% (4/6) in patients with myoblasts positive for DR4/DR5 expression; no tumor responses were observed with eftoza monotherapy. These data indicate that combination therapy with eftoza plus venetoclax to simultaneously activate the extrinsic and intrinsic apoptosis-signaling pathways may improve clinical benefit compared with venetoclax monotherapy in relapsed/refractory AML with an acceptable toxicity profile. This trial was registered at www.clinicaltrials.gov as #NCT03082209.

Synthesis of quercetin functionalized wurtzite type zinc oxide nanoparticles and their potential to regulate intrinsic apoptosis signaling pathway in human metastatic ovarian cancer

In the present study, the wurtzite (WZ) type of zinc oxide (ZnO) nanoparticles were synthesized and functionalized with quercetin (ZnO@Quercetin) for the treatment of ovarian cancer. Initially, the chemical synthesis of ZnO nanoparticles was confirmed with DRS UV–vis spectroscopy and the bandgap of the ZnO revealed that the WZ type of nanoparticles. The electron microscopy analysis showed the hexagonal shape, monocrystalline nature of nanoparticles with an average size of 20–25 nm and the SAED pattern showed the interplanar planes for WZ type nanoparticles. XRD analysis revealed the presence of strong peaks corresponding to ZnO nanoparticles and the Raman spectroscopic analysis showed the characteristic peaks at E2 (high) and E1 vibrational mode for WZ type of ZnO nanoparticles. The in vitro cytotoxic activity of ZnO@Quercetin nanoparticles showed the excellent activity by generating intercellular oxidative stress and depolarization of mitochondrial membrane potential against human ovarian cancer cells. The dual-staining assay showed that the ZnO@Quercetin induces late apoptosis through activation of the intrinsic apoptosis signaling pathway in PA-1 cells. Together, the present study indicates the ZnO@Quercetin nanoparticles can be used for the treatment of human metastatic ovarian cancer.

Chemical profiling of marine seaweed Halimeda gracilis using UPLC-ESI-Q-TOF-MSE and evaluation of anticancer activity targeting PI3K/AKT and intrinsic apoptosis signaling pathway

Marine seaweeds are predominant for nutraceuticals and have been food source since ancient times and are currently being used in Chinese medicines and Japanese traditional medicines. In the present study, the chemical profile analysis of Halimeda gracilis was performed using UPLC-ESI-Q-TOF-MSE analysis and assessed for its anticancer activity. A cursory investigation of the total ion chromatograms of the both methanol (MHG) and ethyl acetate (EAHG) of H. gracilis extracts reveals that both extracts have different kind of metabolites including phenols and its derivatives, diterpenes, cinnamic acids derivatives etc. The in vitro anticancer activity of EAHG and MHG exhibiting significant activity and induced apoptosis against skin cancer cells by generating excessive ROS, damaging the mitochondrial membrane and nuclear components. Further, the western blot analysis showed that the EAHG and MHG downregulates the oncoproteins PI3K, AKT, p-AKT, and BcL2 and upregulates the apoptotic proteins Bax, Cyto C, p21, p53, Caspase 9 and Caspase 3. To best of our knowledge, this is the first report which implies the UPLC-ESI-Q-TOF-MSE based chemical profiling of H. gracilis and can be used for the treatment of cancer.

GBP5 promotes liver injury and inflammation by inducing hepatocyte apoptosis.

Liver injury is the first step in causing fibrosis, cirrhosis, and liver cancer, leading to mortality. However, the drivers of progressive liver injury are still incompletely defined. Here, we identify GBP5 as a major factor causing liver injury and inflammation. We show that the expression of GBP5 is abnormally elevated in the damaged liver, and its expression depends at least partially on the NF-κB-inducing kinase (NIK)/NF-κB2signaling pathway. Knockout of Gbp5 ameliorates D-galactosamine/lipopolysaccharide (GalN/LPS)-induced liver injury and inflammation. Conversely, liver-specific overexpression of GBP5 induces liver injury and inflammation. Mechanistically, GBP5 induces hepatocyte apoptosis through the activation of both calpain/caspase 12/caspase 3 and TNFα/caspase 8/caspase 3signaling pathways. Inhibition of either calpain activity or caspase 3 prevents GBP5-induced cell death. Our data demonstrate that GBP5 expression is induced by toxins or the NIK signaling pathway, which promotes both extrinsic and intrinsic apoptosis signaling pathways and further induces liver injury, providing a novel drug target for the treatment of liver injury and inflammation.

Insulin growth factor-1 enhances proliferation and inhibits apoptosis of neural progenitor cells by phosphorylation of Akt/mTOR/p70S6K molecules and triggering intrinsic apoptosis signaling pathway

Neural progenitor cells (NPCs) transplantation is known as a potential strategy for treating spinal cord injury (SCI). This study aimed to investigate effects of insulin growth factor-1 (IGF-I) on NPCs proliferation and clarify associated mechanisms. NPCs isolated from T8-T10 segmental spinal cord tissues of rats were cultured and identification. Then, lentivirus packing plasmids containing IGF-I was constructed and used for NPCs infection. Cell proliferation was evaluated by detecting 5-Bromodeoxyuridine (BrdU) expression in NPCs, cell differentiation was detected using double-labeling immunofluorescence staining while cell apoptosis was detected using TUNEL assay. In addition, the signal expression of Akt/mTOR/p70S6K in NPCs cells were investigated using immunofluorescence staining and western blot assay. The experimental group was defined as pCMV-IGF-I group, while the negative control group was defined as pCMV-LacZ group. Cells infected with pCMV-IGF-I lentivirus followed by addition of 100mg/ml rapamycin were defined as pCMV-IGF-I + Rapa group. NPCs were successfully isolated, identified and cultured. IGF-I overexpression significantly inhibited cell apoptosis and enhanced cell migration. Akt/mTOR/ p70S6K signaling cascade was proved to be present in NPCs, IGF-I overexpression significantly activated Akt/mTOR/p70S6K signaling cascade, while rapamycin addition inhibited its expression. Also, the activated Akt/mTOR/p70S6K signal cascade induced by IGF-I significantly enhanced BrdU expression and inhibited cell apoptosis, and promoted the differentiation of NPC into the neuronal system. However, the rapamycin addition inhibited the cell response induced by IGF-I overexpression. IGF-I overexpression could enhance cell proliferation, inhibit cell apoptosis and promote their differentiation into neuronal systems by activating Akt/mTOR/p70S6K signaling cascade in vitro, indicating that the Akt/mTOR/p70S6K signaling cascade may be the potentially mechanism for the endogenous repair and remodeling of spinal cord after injury.

Abstract 1947: Brought to light: the homotypic interaction pattern of Bcl-2 effector transmembrane domains in a bimolecular luciferase complementation assay

Abstract The intrinsic apoptosis signaling pathway comprises the intimate interaction network of the Bcl-2 protein family, in which both pro- and antiapoptotic members pushing cell fate to either survival or death. As a critical event, oligomerization of pore-forming effector proteins BAX, BAK and BOK drive mitochondrial outer membrane permeabilization (MOMP), which results in Cytochrome C release and ultimately apoptotic cell death. Thus far, investigations focus on protein-protein interactions mediated by the BH3-domain and hydrophobic groove. These interactions are targeted by BH3 mimetics that represent highly efficient anti-cancer drugs. In contrast, the C-terminal α-9 helices, known as transmembrane domains (TMD), tend to be neglected as a potential secondary interaction site with other Bcl-2 proteins. However, TMDs strongly affect subcellular localization and there is increasing evidence that TMDs crucially influence Bcl-2 protein interactions and therefore apoptosis signaling. Although TMDs are widely abundant in pro- and anti-apoptotic Bcl-2 proteins, their contribution to the complex Bcl-2 interaction network remains largely in the dark. Aiming to shed more light on the interactions of TMD among effector Bcl-2 proteins, we generated a bimolecular complementation assay in which effector TMD peptides are coupled to a bimolecular split-luciferase system. In addition, vectors encode for simultaneous expression of fluorophores to allow control of transgene expression. Human cell lines were co-transfected with combinations of TMD expression constructs yielding luminescence-based interaction data with a fluorescence-based normalization. Interestingly, we found an almost exclusively homotypic TMD interaction among the TMDs of BAX, BAK and BOK. Moreover, confocal microscopy with modified fluorophore-coupled TMD peptides revealed that TMD sequences were sufficient to locate BAX TMD and BAK TMD peptides effectively to mitochondria, while BOK TMD peptides were mainly localized to the endoplasmic reticulum. Strikingly, exchanging TMD sequences in full-length effector proteins profoundly modulated cell death induction. These results strongly suggest a central functional relevance of the α-9-helices in promoting homotypic interactions of effectors BAX, BAK and BOK during oligomerization and pore formation. In contrast, putative heterotypic interaction among effector proteins is not reflected by the newly generated TMD interaction assay. Thus, effector TMDs are a vital factor for specific protein localization and cell death induction displaying specific functionality in each effector protein. Our findings underline the importance of further investigating the TMD region as a potential oncogenic feature influencing interaction of Bcl-2 proteins and therefore as a potential target for therapeutic intervention. Citation Format: Tobias B. Beigl, Sandra Weller, Benjamin Schäfer, Kathrin Böpple, Lara-Sophie Rieder, Hans-Georg Kopp, Markus Rehm, Walter E. Aulitzky, Frank Essmann. Brought to light: the homotypic interaction pattern of Bcl-2 effector transmembrane domains in a bimolecular luciferase complementation assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1947.

Abbv-621 Is a Novel and Potent TRAIL Receptor Agonist Fusion Protein That Induces Apoptosis Alone and in Combination with Navitoclax and Venetoclax in Hematological Tumors

Cell death can be initiated through activation of the extrinsic and intrinsic apoptotic signaling pathways. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily of cytokines, preferentially triggers the extrinsic apoptotic pathway by binding as a trimer to two closely related cell surface death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5). When these receptors undergo trimerization, it leads to the formation of the death-inducing signaling complex (DISC) to recruit and activate downstream caspases that ultimately leads to apoptotic cell death. Since TRAIL was found to induce apoptosis, several TRAIL receptor agonists have been developed for the treatment of cancer. ABBV-621 is a novel, second generation TRAIL receptor agonist that is currently being tested in Phase 1 clinical trials. It is an engineered fusion protein consisting as an IgG1-Fc linked to a single chain trimer of TRAIL subunits resulting in a total of six death receptor binding sites per molecule in order to maximize receptor clustering. ABBV-621 exhibited potent single agent activity in acute myeloid lymphoma (AML) and diffuse large B-cell lymphoma (DLBCL) cell lines following 24hrs treatment. This activity was rapid and mechanism-based since activation of downstream apoptotic signaling events (caspase activation, mitochondrial depolarization, phosphatidylserine exposure) were observed as early as 1 hour following the addition of ABBV-621, and cell death could be completely blocked with the pan caspase inhibitor z-VAD-FMK . In vivo, ABBV-621 demonstrated robust single agent anti-tumor activity in pre-clinical models of AML and DLBCL.The intrinsic apoptotic pathway is regulated by the BCL-2 protein family which controls the release of cytochrome c from the mitochondria resulting in the activation of downstream caspases. Because the two apoptotic pathways are linked, the intrinsic pathway can influence cell death mediated through the extrinsic pathway. The elevated expression of the anti-apoptotic proteins, BCL-2 and BCL-XL, can inhibit the activation of the intrinsic apoptotic pathway and enable resistance to anti-cancer therapeutics, including TRAIL. Venetoclax (ABT-199), a BCL-2 selective inhibitor, and navitoclax (ABT-263) a BCL-2/BCL-XL selective inhibitor, were tested in combination with ABBV-621 in a number of hematologic tumor cell lines in vitro and in vivo . The anti-tumor activity of ABBV-621 in combination with venetoclax or navitoclax exceeded that of either agent tested alone in pre-clinical and AML and DLBCL xenograft models.Collectively, these data highlight that targeting the extrinsic apoptosis signaling pathway with either ABBV-621 alone or in combination with venetoclax/navitoclax to harness the intrinsic apoptosis signaling pathway has potential therapeutic benefit in hematologic malignancies.Disclosures:All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication. DisclosuresTahir:Abbvie: Employment, Equity Ownership. Smith:Abbvie: Employment, Equity Ownership. Solomon:Abbvie: Employment, Equity Ownership. Zhang:Abbvie: Employment, Equity Ownership. Xue:Abbvie: Employment, Equity Ownership. Xiao:Abbvie: Employment, Equity Ownership. Cheng:Abbvie: Employment, Equity Ownership. Buchanan:Abbvie: Employment, Equity Ownership. Morgan-Lappe:Abbvie: Employment, Equity Ownership. Phillips:Abbvie: Employment, Equity Ownership.

MiRNA-193a-3p Regulates the AKT2 Pathway to Inhibit the Growth and Promote the Apoptosis of Glioma Cells by Targeting ALKBH5.

Emerging evidence indicates that microRNA (miR)-193a-3p is involved in the tumor progression of various cancers. However, the biological functions and precise molecular mechanisms of miR-193a-3p in gliomas have not been well documented. Accordingly, this study focused on the tumor suppressor role and molecular mechanisms of miR-193a-3p in glioma cells. miR-193a-3p expression was determined by qRT-PCR in glioma tissues and cell lines. U251 and U87 glioma cells were transfected with a miR-193a-3p mimic. The effects of miR-193a-3p on cell growth and apoptosis were investigated using MTT, colony-forming, and flow cytometry assays. Overexpression of miR-193a-3p in U87 cells also significantly suppressed tumorigenicity and induced apoptosis in the xenograft mouse model. Luciferase assays were conducted to determine if ALKBH5 is a direct target of miR-193a-3p in glioma cells. Immunoprecipitation was used to explore the interaction between ALKBH5 and RAC-serine/threonine-protein kinase 2 (AKT2) in glioma cells. miR-193a-3p was downregulated in glioma tissues and cell lines. miR-193a-3p treatment suppressed proliferation and promoted apoptosis in both U251 and U87 cells. Bioinformatics analysis and luciferase reporter assay identified a novel miR-193a-3p target, ALKBH5. Notably, the antitumor effect of miR-193a-3p transfection in glioma cells may be due to the miR-193a-3p–induced inhibition of AKT2 expression caused by the suppression of ALKBH5 expression. Furthermore, immunoprecipitation indicated that ALKBH5 physically interacted with AKT2 through an RNA-independent mechanism in glioma cells. miR-193a-3p directly targets ALKBH5 to inhibit the growth and promote the apoptosis of glioma cells by suppressing the AKT2 pathway both in vitro and in vivo, and the physical interaction between ALKBH5 and AKT2 is essential for suppressing cell apoptosis by upregulating miR-193a-3p in glioma cells. Our study revealed that the antitumor effects of miR-193a-3p on glioma cells is due to ALKBH5 mediation of the AKT2-induced intrinsic apoptosis signaling pathway.

Preventive Effects against Retinal Degeneration by Centella asiatica Extract (CA-HE50) and Asiaticoside through Apoptosis Suppression by the Nrf2/HO-1 Signaling Pathway.

Age-related macular degeneration (AMD) is caused by the chronic and gradual oxidative degeneration of the retina. Unfortunately, the general purpose of current treatments is to slow AMD progression, as the retina cannot be restored to its pre-AMD condition. We aimed to identify natural products that can be potential treatments that prevent AMD and can delay the development of late-AMD and selected Centella asiatica extract (CA-HE50), which shows excellent efficacy in cytoprotection. In animal experiments using N-methyl-N-nitrosourea (MNU), CA-HE50 dramatically increased the thickness of photoreceptors and the outer nuclear layer (ONL) and the number of nuclei in the ONL (p < 0.05). Using retinal epithelial ARPE-19 cells showed that CA-HE50 inhibited apoptosis through inhibition of the intrinsic apoptosis signaling pathway and cell cycle regulation (p < 0.05). The anti-apoptotic efficacy was confirmed to be due to activation of the Nrf2/HO-1 antioxidation pathway (p < 0.05). These results were also observed with asiaticoside, a functional substance of CA-HE50. In addition, the accumulation of oxidized-N-retinylidene-N-retinylethanolamine (A2E), which induces AMD, was inhibited by CA-HE50, resulting in increased ARPE-19 cell viability (p < 0.05). This study demonstrates that CA-HE50 is worth further research and human application tests, to develop it as a raw material for treatment or dietary supplement for the prevention of AMD.

γ‑irradiated prednisolone promotes apoptosis of liver cancer cells via activation of intrinsic apoptosis signaling pathway.

Prednisolone is an anti-inflammatory drug used to treat a number of conditions, including liver disease and cancer. Numerous studies have demonstrated that glucocorticoids such as prednisolone modified by ionizing radiation can promote anticancer activity in cancer cells. To the best of our knowledge, however, the effect of ionizing radiation on prednisolone structure and cancer cells has not yet been identified. The present study created a novel prednisolone derivative using γ-irradiation, and its anticancer properties were investigated in liver cancer cells. The present study confirmed the structure of the new prednisolone derivative using liquid chromatogram-mass spectrometry. MTT assays determined the cytotoxic effects of γ-irradiated (IR)-prednisolone in liver cancer cells. Flow cytometry analysis evaluated apoptosis, mitochondrial membrane potential and cell cycle distribution. Western blotting was used to analyze the proteins associated with apoptosis. The chromatogram profile revealed that IR-prednisolone produced a number of peaks compared with the single peak of the original prednisolone. In contrast to prednisolone, the MTT results showed that IR-prednisolone significantly prevented the growth of liver cancer cells. IR-prednisolone promoted apoptosis and arrested the cell cycle at the G0/G1 stage in Huh7 cells. IR-prednisolone also altered the mitochondrial membrane potential and activated caspase-associated proteins, which activated the intrinsic apoptotic signaling pathway. In conclusion, IR-prednisolone promoted anticancer effects in liver cancer cells via apoptosis activation. The present study demonstrated that IR-prednisolone may be a potential anticancer agent against liver cancer, although specific molecules have yet to be identified.

The natural compound n-butylidenephthalide kills high-grade serous ovarian cancer stem cells by activating intrinsic apoptosis signaling pathways.

High-grade serous ovarian cancer (HGSOC) constitutes 80% of ovarian cancer. Cancer stem cells (CSCs) are responsible for most of the tumor metastasis and chemoresistance. n-Butylidenephthalide (BP) is a potential anti-tumor agent for treating a variety of cancers. The aim of this study was to evaluate the effect of BP on CSCs of HGSOC. CSCs were isolated using the CSC marker (ALDH; aldehyde dehydrogenase) from KURAMOCHI and OVSAHO cells (HGSOC cell lines). The cell proliferation, IC50 (the half-maximal inhibitory concentration), cell migration and invasion, TUNEL (terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling) assay, western blot of ovarian CSC were evaluated. The animal xenograft studies were evaluated on an immunodeficient mouse model. The results showed the proliferation of ALDH+ cells was greater than that of ALDH- cells. The dosage of IC50 of BP was higher in ALDH+ cells than in mixed cancer cells (317.2 vs. 206.5 μg/ml) in KURAMOCHI cells, but not in OVSAHO cells (61.1 vs. 48.5 μg/ml). BP could inhibit the migration and invasion of both cancer stem cells. BP treatment could activate apoptosis signaling, as indicated by the TUNEL assay and the increased expression of cleaved caspase-3, -7, and -9 but not cleaved caspase-8. A low dose of BP (20 and 25 μg/mL) treatment could increase the toxicity of taxol and cisplatin. In the animal model, BP (200 mg/kg) treatment also decreased the KURAMOCHI and OVSAHO tumor growth rate and induced tumor apoptosis. In conclusion, BP could kill ALDH+ CSCs of HGSOC in vitro and in vivo by inducing apoptosis. BP may provide a new therapeutic approach for HGSOC.

Drug repurposing and relabeling for cancer therapy: Emerging benzimidazole antihelminthics with potent anticancer effects

Origin of drug and radio-refractory clones, cancer stem-like cells, and rapid angiogenesis and metastasis are among the primary concerns that limit the efficacy of anticancer treatments, emphasizing the urgency of developing new therapeutics. Factors like high attrition rates, huge investments, patients' heterogeneity, and diverse molecular subtypes have challenged the rapid development of anticancer drugs. Treatment with repurposing pleiotropic benzimidazole antihelminthics, like mebendazole, albendazole, and flubendazole has recently opened a new window, owing to their easy access, low cost as a generic drug, and long track record of safe use in the human population. This review highlights the outcomes of preclinical and clinical studies of these drugs as a potent anticancer agent(s) conducted in the last two decades. Substantial preclinical studies, as well as limited clinical trials, suggest noteworthy anticancer potency of these pleiotropic benzimidazoles, particularly as potent microtubule disrupting, anti-angiogenic, and anti-metastatic agents, inhibitors of the immune checkpoint, hypoxia-inducible factor, epithelial-mesenchymal transition, cancer stemness, and multidrug resistance protein 1, and inducers of apoptosis and M1 polarization. These anticancer effects are attributed to multiple action points, including intrinsic apoptosis, canonical Wnt/β-catenin, JAK/STAT-3, JNK, MEK/ERK, and hedgehog signaling pathways. The effective anticancer properties of mebendazole, albendazole, and flubendazole either alone or synergistically with frontline drugs, warrant their validation through controlled clinical trials to use them as promising avenues to anticancer therapy.