BCL-2 in the crosshairs: tipping the balance of life and death

Integrated network pharmacology, molecular docking and pharmacodynamic study reveals protective effects and mechanisms of corilagin against cerebral ischemia-induced injury

BACKGROUND

Stroke is one of the leading causes of death and long-term disability worldwide. Previous studies have found that corilagin has antioxidant, anti-inflammatory, anti-atherosclerotic and other pharmacological activities and has a protective effect against cardiac and cerebrovascular injury.

OBJECTIVES

The aim of this study was to investigate the protective effects of corilagin against ischemic stroke and to elucidate the underlying molecular mechanisms using network pharmacology, molecular docking, and animal and cell experiments.

METHODS

We investigated the potential of corilagin to ameliorate cerebral ischemia-reperfusion injury using in vivo rat middle cerebral artery occlusion/reperfusion (MCAO/R) and in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) models.

RESULTS

Our results suggest that corilagin may exert its anti-ischemic stroke effect by interacting with 92 key targets, including apoptosis-associated proteins (Bcl-2, Bax, caspase-3) and PI3K/Akt signaling pathway-related proteins. In vivo and in vitro experiments showed that corilagin treatment improved neurological deficits, attenuated cerebral infarct volume, and mitigated neuronal damage in MCAO/R rats. Corilagin treatment also enhanced the survival of PC12 cells exposed to OGD/R, reduced the rate of LDH leakage, inhibited cell apoptosis, and activated the PI3K/Akt signaling pathway. Importantly, the effects of corilagin on the PI3K/Akt signaling pathway and apoptosis-associated proteins were reversed by the PI3K-specific inhibitor LY294002.

CONCLUSIONS

These results indicate that the molecular mechanism of the anti-ischemic effect of corilagin involves inhibiting neuronal apoptosis and activating the PI3K/Akt signaling pathway. These findings provide a theoretical and experimental basis for the further development and application of corilagin as a potential anti-ischemic stroke agent.

Targeting autophagy and beyond: Deconvoluting the complexity of Beclin-1 from biological function to cancer therapy

Beclin-1 is the firstly-identified mammalian protein of the autophagy machinery, which functions as a molecular scaffold for the assembly of PI3KC3 (class III phosphatidylinositol 3 kinase) complex, thus controlling autophagy induction and other cellular trafficking events. Notably, there is mounting evidence establishing the implications of Beclin-1 in diverse tumorigenesis processes, including tumor suppression and progression as well as resistance to cancer therapeutics and CSC (cancer stem-like cell) maintenance. More importantly, Beclin-1 has been confirmed as a potential target for the treatment of multiple cancers. In this review, we provide a comprehensive survey of the structure, functions, and regulations of Beclin-1, and we discuss recent advances in understanding the controversial roles of Beclin-1 in oncology. Moreover, we focus on summarizing the targeted Beclin-1-regulating strategies in cancer therapy, providing novel insights into a promising strategy for regulating Beclin-1 to improve cancer therapeutics in the future.

Carthamus tinctorius L. Seed and Taraxacum coreanum Attenuate Oxidative Stress Induced by Hydrogen Peroxide in SH-SY5Y Cells

Oxidative stress is closely associated with the pathology of neurodegenerative diseases. The seeds of Carthamus tinctorius L. (CTS) and Taraxacum coreanum (TC) are reported as herbal medicines for neuroprotection. This study investigated the protective effect of CTS, TC, and their combination against oxidative stress induced by H2O2 in SH-SY5Y cells. The CTS and TC combination dose-dependently increased DPPH and ·OH radical scavenging activities compared with non-combination. The combination showed a higher increased cell survival rate in H2O2-stimulated SH-SY5Y cells than CTS or TC. Moreover, CTS, TC, and their combination-treated cells reduced LDH release and apoptotic cells. CTS, TC, and their combination also inhibited NO and ROS generation. Further, the combination of up-regulated antioxidant enzymes (superoxide dismutase and glutathione peroxidase) and Bcl-2 protein expressions and down-regulated Bax expression. These findings suggest that the combination of CTS and TC may be beneficial to prevent and treat oxidative stress-mediated neurodegenerative diseases.

Identification of molecular signatures and molecular dynamics simulation of highly deleterious missense variants of key autophagy regulator beclin 1: a computational based approach

Beclin 1 is a key autophagy regulator that also plays significant roles in other intracellular processes such as vacuolar protein sorting. Beclin 1 protein functions as a scaffold in the formation of a multiprotein assemblage during autophagy. Beclin 1 is involved in various diseases such as cancers, neurodegenerative and autophagy-related disorders. In this study, we have used various in silico tools to scan beclin 1 at the molecular level to find its molecular signatures. We have predicted and analysed deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) of beclin 1 causing alterations in its structure and also affecting its interactions with other proteins. In total, twelve coding region deleterious variants were predicted using sequence-based tools and nine were predicted using various structure-based tools. The molecular dynamics (MD) simulations revealed an altered stability of the native structure due to the introduction of mutations. Destabilization of beclin 1 ECD domain was observed due to nsSNPs W300R and E302K. Beclin 1 deleterious nsSNPs were predicted to show significant effects on beclin 1 interactions with ATG14L1, UVRAG and VPS34 proteins and were also predicted to alter the protein-protein interface of beclin 1 complexes. Additionally, beclin 1 was predicted to have thirty-one potential phosphorylation and three ubiquitination sites. In conclusion, the molecular details of beclin 1 could help in the better understanding of its functioning. The study of nsSNPs and their effect on beclin 1 and its interactions might aid in understanding the basis of anomalies caused due to beclin 1 dysfunction.Communicated by Ramaswamy H. Sarma.

Role of microglia autophagy and mitophagy in age-related neurodegenerative diseases

Microglia, characterized by responding to damage, regulating the secretion of soluble inflammatory mediators, and engulfing specific segments in the central nervous system (CNS), function as key immune cells in the CNS. Emerging evidence suggests that microglia coordinate the inflammatory responses in CNS system and play a pivotal role in the pathogenesis of age-related neurodegenerative diseases (NDDs). Remarkably, microglia autophagy participates in the regulation of subcellular substances, which includes the degradation of misfolded proteins and other harmful constituents produced by neurons. Therefore, microglia autophagy regulates neuronal homeostasis maintenance and process of neuroinflammation. In this review, we aimed at highlighting the pivotal role of microglia autophagy in the pathogenesis of age-related NDDs. Besides the mechanistic process and the co-interaction between microglia autophagy and different kinds of NDDs, we also emphasized potential therapeutic agents and approaches that could be utilized at the onset and progression of these diseases through modulating microglia autophagy, including promising nanomedicines. Our review provides a valuable reference for subsequent studies focusing on treatments of neurodegenerative disorders. The exploration of microglia autophagy and the development of nanomedicines greatly enhances current understanding of NDDs.

Going beyond Binary: Rapid Identification of Protein-Protein Interaction Modulators Using a Multifragment Kinetic Target-Guided Synthesis Approach

Kinetic target-guided synthesis (KTGS) is a powerful screening approach that enables identification of small molecule modulators for biomolecules. While many KTGS variants have emerged, a majority of the examples suffer from limited throughput and a poor signal/noise ratio, hampering reliable hit detection. Herein, we present our optimized multifragment KTGS screening strategy that tackles these limitations. This approach utilizes selected reaction monitoring liquid chromatography tandem mass spectrometry for hit detection, enabling the incubation of 190 fragment combinations per screening well. Consequentially, our fragment library was expanded from 81 possible combinations to 1710, representing the largest KTGS screening library assembled to date. The expanded library was screened against Mcl-1, leading to the discovery of 24 inhibitors. This work unveils the true potential of KTGS with respect to the rapid and reliable identification of hits, further highlighting its utility as a complement to the existing repertoire of screening methods used in drug discovery.

Epigenetics as a mediator of plasticity in cancer

The concept of an epigenetic landscape describing potential cellular fates arising from pluripotent cells, first advanced by Conrad Waddington, has evolved in light of experiments showing nondeterministic outcomes of regulatory processes and mathematical methods for quantifying stochasticity. In this Review, we discuss modern approaches to epigenetic and gene regulation landscapes and the associated ideas of entropy and attractor states, illustrating how their definitions are both more precise and relevant to understanding cancer etiology and the plasticity of cancerous states. We address the interplay between different types of regulatory landscapes and how their changes underlie cancer progression. We also consider the roles of cellular aging and intrinsic and extrinsic stimuli in modulating cellular states and how landscape alterations can be quantitatively mapped onto phenotypic outcomes and thereby used in therapy development.

Tetrahedral framework nucleic acids alleviate irradiation-induced salivary gland damage

In this study, we investigated the role of tetrahedral framework nucleic acids (tFNAs) in irradiation-induced salivary gland damage in vitro and in vivo. Irradiation-damaged submandibular gland cells (SMGCs) were treated with different concentrations of tFNAs. Cell activity was measured by CCK-8 assay. Cell death was detected by Calcein-AM/PI double staining. Cell apoptosis was assessed by flow cytometry. The expression of apoptosis proteins and inflammatory cytokines were detected by western blot. Body weight, drinking volume, saliva flow rate and lag time was measured 8 weeks after irradiation. Micromorphological changes of submandibular gland were assessed by haematoxylin-eosin and masson staining. Cell proliferation, apoptosis and microvessel density of submandibular gland were evaluated by immunohistochemical staining. tFNAs could promote cell proliferation, inhibit cell apoptosis of irradiation-damaged SMGCs and reduce irradiation induced cell death. Mechanism studies revealed that tFNAs inhibited cell apoptosis through regulating the Bcl-2/Bax/Caspase-3 signalling pathway and inhibited the release of TNF-α, IL-1β and IL-6 to reduce cell damage caused by inflammation. Animal experiments showed that tFNAs could alleviate irradiation-induced weight loss, increased water intake, decreased saliva production and prolonged salivation lag time and could ameliorate salivary gland damage. tFNAs have a positive effect on alleviating irradiation-induced salivary gland damage and might be a promising agent for the treatment of this disease.

Polyphyllin II induced apoptosis of NSCLC cells by inhibiting autophagy through the mTOR pathway

CONTEXT

Polyphyllin II (PPII) is a steroidal saponin isolated from Rhizoma Paridis. It exhibits significant antitumor activity such as anti-proliferation and pro-apoptosis in lung cancer.

OBJECTIVE

To explore whether PPII induce autophagy and the relationship between autophagy and apoptosis in non-small cell lung cancer (NSCLC) cells.

MATERIALS AND METHODS

The effects of PPII (0, 1, 5, and 10 μM) were elucidated by CCK8 assay, colony formation test, TUNEL staining, MDC method, and mRFP-GFP-LC3 lentivirus transfection in A549 and H1299 cells for 24 h. DMSO-treated cells were selected as control. The protein expression of autophagy (LC3-II, p62), apoptosis (Bcl-2, Bax, caspase-3) and p-mTOR was detected by Western blotting. We explored the relationship between autophagy and apoptosis by autophagy inhibitor CQ (10 μM) and 3-MA (5 mM).

RESULTS

PPII (0, 1, 5, and 10 μM) inhibited the proliferation and induced apoptosis. The IC₅₀ values of A549 and H1299 cells were 8.26 ± 0.03 and 2.86 ± 0.83 μM. We found that PPII could induce autophagy. PPII promoted the formation of autophagosome, increased the expression of LC3-II/LC3-I (p < 0.05), while decreased p62 and p-mTOR (p < 0.05). Additionally, the co-treatment with autophagy inhibitors promoted the protein expression of c-caspase-3 and rate of Bax/Bcl-2 (p < 0.05), compared with PPII-only treatment group. Therefore, our results indicated that PPII-induced autophagy may be a mechanism to promote cell survival, although it can also induce apoptosis.

CONCLUSIONS

PPII-induced apoptosis exerts its anticancer activity by inhibiting autophagy, which will hopefully provide a prospective compound for NSCLC treatment.

Anti-Tumorigenic Effect of a Novel Derivative of 2-Hydroxyoleic Acid and the Endocannabinoid Anandamide on Neuroblastoma Cells

Modulation of the endogenous cannabinoid system has been suggested as a potential anticancer strategy. In the search for novel and less toxic therapeutic options, structural modifications of the endocannabinoid anandamide and the synthetic derivative of oleic acid, Minerval (HU-600), were done to obtain 2-hydroxy oleic acid ethanolamide (HU-585), which is an HU-600 derivative with the anandamide side chain. We showed that treatment of SK-N-SH neuroblastoma cells with HU-585 induced a better anti-tumorigenic effect in comparison to HU-600 as evidenced by 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide assay, colony-forming assay, and migration assay. Moreover, HU-585 demonstrated pro-apoptotic properties shown by increased levels of activated caspase-3 following treatment and a better senescence induction effect in comparison to HU-600, as demonstrated by increased activity of lysosomal β-galactosidase. Finally, we observed that combined treatment of HU-585 with the senolytic drugs ABT-263 in vitro, and ABT-737 in vivo resulted in enhanced anti-proliferative effects and reduced neuroblastoma xenograft growth in comparison to treatment with HU-585 alone. Based on these results, we suggest that HU-585 is a pro-apoptotic and senescence-inducing compound, better than HU-600. Hence, it may be a beneficial option for the treatment of resistant neuroblastoma especially when combined with senolytic drugs that enhance its anti-tumorigenic effects.

t(14;18) Translocations in Dioxin-Exposed Workers

OBJECTIVE

To determine if occupational exposure to dioxins is associated with an increased frequency of t(14;18) translocations.

METHODS

A cross-sectional analysis of serum dioxin levels and t(14;18) frequencies in peripheral blood mononuclear cells in 218 former chemical plant workers and 150 population controls.

RESULTS

The workers had significantly higher geometric mean serum levels of 2,3,7,8-TCDD (26.2 vs 2.5 ppt) and TEQ (73.8 vs 17.7 ppt) than controls. There were no significant differences in the prevalence or frequency of t(14;18) translocations in the workers compared to controls. Among former workers with current or past chloracne who were t(14;18) positive, the frequency of translocations significantly increased with quartiles of 2,3,7,8-TCDD and TEQ.

CONCLUSION

Chloracne appears to modulate the association between dioxin exposure and increased frequency of t(14;18) translocations.

An Insight on the Pathways Involved in Crizotinib and Sunitinib Induced Hepatotoxicity in HepG2 Cells and Animal Model

Both crizotinib and sunitinib, novel orally-active multikinase inhibitors, exhibit antitumor activity and extend the survival of patients with a malignant tumor. However, some patients may suffer liver injury that can further limit the clinical use of these drugs, however the mechanisms underlying hepatotoxicity are still to be elucidated. Thus, our study was designed to use HepG2 cells in vitro and the ICR mice model in vivo to investigate the mechanisms of hepatotoxicity induced by crizotinib and sunitinib. Male ICR mice were treated orally with crizotinib (70 mg/kg/day) or sunitinib (7.5 mg/kg/day) for four weeks. The results demonstrated that crizotinib and sunitinib caused cytotoxicity in HepG2 cells and chronic liver injury in mice, which were associated with oxidative stress, apoptosis and/or necrosis. Crizotinib- and sunitinib-induced oxidative stress was accompanied by increasing reactive oxygen species and malondialdehyde levels and decreasing the activity of superoxide dismutase and glutathione peroxidase. Notably, the activation of the Kelch-like ECH-associated protein-1/Nuclear factor erythroid-2 related factor 2 signaling pathway was involved in the process of oxidative stress, and partially protected against oxidative stress. Crizotinib and sunitinib induced apoptosis via the mitochondrial pathway, which was characterized by decreasing Bcl2/Bax ratio to dissipate the mitochondrial membrane potential, and increasing apoptotic markers levels. Moreover, the pan-caspase inhibitor Z-VAD-FMK improved the cell viability and alleviated liver damage, which further indicated the presence of apoptosis. Taken together, this study demonstrated that crizotinib- and sunitinib-caused oxidative stress and apoptosis finally impaired hepatic function, which was strongly supported by the histopathological lesions and markedly increased levels of serum alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase.

Gigantol inhibits proliferation and enhanced oxidative stress-mediated apoptosis through modulating of Wnt/β-catenin signaling pathway in HeLa cells

Cervical cancer is one of the leading malignant cancers that is the fourth prominent cause of malignancy-related mortality in women globally. There is a predominant validation to a beneficial target in Wnt/β-catenin signaling in cervical carcinogenesis as they are very much deregulated in cancer. Previous studies reported Gigantol (GG) showed suppressive properties on the Wnt/β-catenin pathway in other tumor cells, but no evidence is available regarding GG suppressing Wnt/β-catenin signaling cervical tumor cells. Hence, the current research was planned to examine the suppressive effects of GG on HeLa cells and investigate the mechanism of action. HeLa cells were treated by GG in various doses and then appraising cell viability, oxidant/antioxidant levels, ∆ѰM status, reactive oxygen species (ROS) generation, apoptosis, and cell proliferation via Wnt/β-catenin signaling. We observed that GG noticeably inhibits cell proliferation, increased ROS generation, lipid peroxidation, mitochondrial membrane depolarization (∆ѰM), and increased apoptotic morphological changes of nuclear fragmentation and condensation. Moreover, GG effectively enhances proapoptotic, decreased ∆ѰM and antioxidant amounts, and mitigated Wnt/β-catenin signaling. Concisely, these findings proved that activating apoptosis and suppression of cell proliferation in GG treated HeLa cells was documented by the alleviation of Wnt/β-catenin signaling. Therefore, this study suggested that GG might develop a therapeutic effect against cervical carcinogenesis.

Exogenous Introduction of Initiator and Executioner Caspases Results in Different Apoptotic Outcomes

The balance of pro-apoptotic and pro-survival proteins defines a cell's fate. These processes are controlled through an interdependent and finely tuned protein network that enables survival or leads to apoptotic cell death. The caspase family of proteases is central to this apoptotic network, with initiator and executioner caspases, and their interaction partners, regulating and executing apoptosis. In this work, we interrogate and modulate this network by exogenously introducing specific initiator or executioner caspase proteins. Each caspase is exogenously introduced using redox-responsive polymeric nanogels. Although caspase-3 might be expected to be the most effective due to the centrality of its role in apoptosis and its heightened catalytic efficiency relative to other family members, we observed that caspase-7 and caspase-9 are the most effective at inducing apoptotic cell death. By critically analyzing the introduced activity of the delivered caspase, the pattern of substrate cleavage, as well as the ability to activate endogenous caspases, we conclude that the efficacy of each caspase correlated with the levels of pro-survival factors that both directly and indirectly impact the introduced caspase. These findings lay the groundwork for developing methods for exogenous introduction of caspases as a therapeutic option that can be tuned to the apoptotic balance in a proliferating cell.

Methylglyoxal-derived hemoglobin advanced glycation end products induce apoptosis and oxidative stress in human umbilical vein endothelial cells

The presence of excess glucose promotes hemoglobin glycation via the biochemical modification of hemoglobin by dicarbonyl products. However, the precise effects of Hb-AGEs in human umbilical vein endothelial cells (HUVECs) are not known to date. Therefore, we investigated the tentative effects of Hb-AGEs in HUVECs. Initially, we used the AGE formation assay to examine the selectivity of MGO toward various proteins. Among all proteins, MGO-Hb-AGEs formation was higher compared to the formation of other dicarbonyl-mediated AGEs. Our next data demonstrated that treatment with 0.5 mg/mL of Hb-AGEs-4w significantly reduced cell viability in HUVECs. Further, we evaluated the role of MGO in conformational and structural changes in Hb. The results showed that Hb demonstrated a highly altered conformation upon incubation with MGO. Moreover, Hb-AGEs-4w treatment strongly increased ROS production, and decreased mitochondrial membrane potential in HUVECs, and moderately reduced the expression of phosphorylated forms of p-38 and JNK. We observed that Hb-AGEs-4w treatment increased the number of apoptotic cells and the Bax/Bcl-2 ratio and cleaved the nuclear enzyme PARP in HUVECs. Finally, Hb-AGEs also inhibited migration and proliferation of HUVECs, thus be physiologically significant in endothelial dysfunction. Taken together, our data suggest that Hb-AGEs may play a critical role in inducing vascular endothelial cell damage. Therefore, this study may provide a plausible explanation for the potential Hb-AGEs in human endothelial cell dysfunction of diabetic patients.

Hydroxyl safflower yellow B combined with doxorubicin inhibits the proliferation of human breast cancer MCF-7 cells

Doxorubicin (DOX) is currently the preferred chemotherapeutic agent for breast cancer, and hydroxyl safflower yellow B (HSYB) has a tumor growth-inhibiting activity. The present study aimed to investigate the effects of HSYB combined with DOX on the proliferation of human breast cancer MCF-7 cells and explore the underlying mechanism. MTT and cell colony formation assays revealed that the proliferation rate of MCF-7 cells was signifiscantly decreased after HSYB and DOX treatment. Combined HSYB and DOX treatment significantly decreased the expression levels of BCL-2 in MCF-7 cells, while the expression levels of apoptosis-associated proteins, including cleaved caspase-9, BAX and cleaved caspase-3, were markedly increased. Furthermore, flow cytometry and western blot analysis demonstrated that combined HSYB and DOX treatment stimulated an increase in intracellular reactive oxygen species and promoted the release of cytochrome c, leading to apoptosis. The current data suggested that the combination of HSYB and DOX may have marked antitumor activity.

Tracking exogenous intracellular casp-3 using split GFP

Cytosolic protein delivery promises diverse applications from therapeutics, to genetic modification and precision research tools. To achieve effective cellular and subcellular delivery, approaches that allow protein visualization and accurate localization with greater sensitivity are essential. Fluorescently tagging proteins allows detection, tracking and visualization in cellulo. However, undesired consequences from fluorophores or fluorescent protein tags, such as nonspecific interactions and high background or perturbation to native protein's size and structure, are frequently observed, or more troublingly, overlooked. Distinguishing cytosolically released molecules from those that are endosomally entrapped upon cellular uptake is particularly challenging and is often complicated by the inherent pH-sensitive and hydrophobic properties of the fluorophore. Monitoring localization is more complex in delivery of proteins with inherent protein-modifying activities like proteases, transacetylases, kinases, etc. Proteases are among the toughest cargos due to their inherent propensity for self-proteolysis. To implement a reliable, but functionally silent, tagging technology in a protease, we have developed a caspase-3 variant tagged with the 11th strand of GFP that retains both enzymatic activity and structural characteristics of wild-type caspase-3. Only in the presence of cytosolic GFP strands 1-10 will the tagged caspase-3 generate fluorescence to signal a non-endosomal location. This methodology facilitates easy screening of cytosolic vs. endosomally-entrapped proteins due to low probabilities for false positive results, and further, allows tracking of the resultant cargo's translocation. The development of this tagged casp-3 cytosolic reporter lays the foundation to probe caspase therapeutic properties, charge-property relationships governing successful escape, and the precise number of caspases required for apoptotic cell death.

Benzoinum from Styrax tonkinensis (Pierre) Craib ex Hart exerts a NVU protective effect by inhibiting cell apoptosis in cerebral ischaemia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Benzoinum (Styraceae) is a traditional Chinese medicine used to treat stroke and other cardio-cerebrovascular diseases for thousands of years. Benzoinum has also proven to have diverse pharmacological activity, but the neuroprotection mechanism of apoptosis in ischaemic stroke was not determined.

AIM OF THIS STUDY

To investigate the protective effect of a neurovascular unit (NVU) and the mechanisms of benzoinum on cerebral ischaemic rats.

MATERIALS AND METHODS

The neuroprotective activity of benzoinum against middle cerebral artery occlusion (MCAO)-induced cerebral ischaemic injury. Neurological scores, 2,3,5-Triphenyltetrazolium chloride (TTC) staining, and hematoxylin-eosin staining (HE) staining were conducted to evaluate the neurological damage. Infarction rate and denatured cell index (DCI) were also calculated. The ultrastructure of neuron and blood-brain-barrier (BBB) was observed by transmission electron microscopy (TEM). Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect Bax, Bcl-2 and Caspase 3 expression. Furthermore, Claudin 5 also was detected through immunohistochemistry.

RESULTS

Benzoinum could significantly improve neurological function score and reduce cerebral infarction rate and DCI. In addition, benzoinum alleviated pathomorphological change and apoptosis in the brain tissue of MCAO rats. The results of TEM and claudin 5 expression of immunohistochemistry showed that benzoinum could play a neuroprotective effect in NVU. Also, benzoinum-enhanced Bcl2, and reduced Bax and Bax/Bcl-2 and Caspase 3, suggest that benzoinum provided a neuroprotective effect by inhibited cell apoptosis.

CONCLUSION

Benzoinum could play a neuroprotective role and regulate apoptosis for repair and stabilisation of NVU. This anti-apoptosis activity might be associated with the downregulation of Bax and Caspase 3, and the upregulation of Bcl2. Our present findings provide a promising medication for the treatment of ischaemic stroke.

Stress responses of testicular development, inflammatory and apoptotic activities in male zebrafish (Danio rerio) under starvation

Food deprivation is a severe stress across multiple fields and challenged to organismal development and immune system. Here, adult male zebrafish were used to investigate the starvation stress on organismal development, spermatogenesis, testicular inflammation and apoptosis. Results showed that the biological indexes, blood parameters, and RNA/DNA ratio in testis dramatically decreased after 1-3 weeks of starvation. The testicular architecture was impaired and the spermatogenesis was retarded with increased proportions of spermatogonia and spermatocytes, and decreased proportion of spermatozoa in the starved fish. The mRNA expressions of amh and sycp3 were downregulated, the retinoic acid content increased at later stage of starvation through the transcriptional regulation of aldh1a2 and cyp26a1. Besides, the immune response was elevated with upregulated mRNA and protein expressions of TNF-α, IL-6, and IL-1β, which indicated the inflammation of opportunistic risk in testis. The apoptotic activity was stimulated, accompanied by differentially upregulated expressions of baxa, casp9, casp3, casp2, and decreased ratio of Bcl-2/Bax in the attenuate testis. Taken together, our findings revealed that the stress responses of testicular development, inflammatory and apoptotic activities in male zebrafish under starvation and pointed out the susceptibility of fish gonad to food fluctuation.

Lead acetate induces apoptosis in Leydig cells by activating PPARγ/caspase-3/PARP pathway

This study was designed to investigate the cytotoxicity of lead acetate (Pb(AC)₂, a representative air pollutant) by focusing on PPARγ/caspase-3/PARP apoptotic signaling pathway and to explore the inhibitory effect of PPARγ antagonist on apoptosis of TM3 Leydig cells. MTT assay was utilized to examine cell viability. Cell apoptosis was analyzed using a flow cytometry by staining with Annexin V-PE/7AAD staining and a fluorescence microscope by staining with Hoechst 33,258. The levels of apoptosis-related proteins were examined using western blot. From the results, Pb reduced significantly TM3 cell proliferation in concentration- and time-dependent manner. It increased significantly apoptosis; increased the PPARγ, Bax, procaspase-3, cleaved caspase-3, proPARP, cleaved PARP levels; and decreased Bcl-2 level in Pb-treated TM3 cells as compared to control cells. Furthermore, pretreatment with PPARγ antagonist significantly attenuated the apoptosis and cleavage of caspase-3 and PARP induced by Pb. Our results suggested that Pb induced cytotoxicity on TM3 Leydig cells, at least in part, by increasing PPARγ expression, stimulating cleavage of caspase-3 and PARP, and then induced cell apoptosis.

Chronic exposure to the gibberellin derivative GA-13315 sensitizes breast cancer MCF-7 cells but not colon cancer HCT116 cells to irinotecan

13-Chlorine-3,15-dioxy-gibberellic acid methyl ester (GA-13315) is a gibberellin derivative that exhibits selective cytotoxicity to multidrug resistant MCF-7/ADR cells and reverses drug resistance when administered at subtoxic doses in combination with chemotherapy drugs. The present study aimed to investigate the impact of chronic GA-13315 exposure on the chemosensitivity of MCF-7 and HCT116 cell lines. Cells were administered a subtoxic dose of 1 µM GA-13315 for 12 weeks and the sensitivity of the cells to GA-13315, irinotecan and cisplatin, was assessed. The Cell Counting Kit-8 assay results demonstrated that the chronic exposure did not induce resistance to GA-13315, in either MCF-7 or HCT116 cells. Notably, MCF-7 cells were sensitized to irinotecan following exposure to GA-13315; however, HCT116 cells were not. The sensitizing effect of GA-13315 was associated with the alterations of topoisomerase 1 (Top1) protein expression, tyrosyl DNA phosphodiesterase 1 and checkpoint kinase 1. Further analysis indicated that GA-13315 caused DNA fragmentation; however, DNA damage was not mediated by a Top1-dependent molecular mechanism, as GA-13315 was revealed not to be a Top1 poison, despite inhibiting the catalytic activity of Top1. Taken together, the results of the present study indicated that GA-13315 may be used for sensitizing MCF-7 cells to irinotecan, as the chronic exposure of GA-13315 to MCF-7 cells still showed sensitizing effects to irinotecan.

The mitochondria/caspase-dependent apoptotic pathway plays a role in the positive effects of a power frequency electromagnetic field on Alzheimer's disease neuronal model

In this study, rat pheochromocytoma (PC12) cells were induced into an Alzheimer's Disease (AD) neuronal model using nerve growth factor (NGF; 50 ng/mL) and Amyloid β_25-35 (20 μmol/L). Changes in the morphological structure, cell viability, apoptosis rate, and expression of apoptosis-related protein induced by exposure to a power frequency electromagnetic field (PF-MF; 50 Hz, 100 μT, 24 h) were detected respectively by light and electron microscopy, the MTT assay, immunohistochemistry, flow cytometry and enzyme-linked immunosorbent assays. The results showed that 3-12 h after PF-MF exposure, the pathological injury was improved partly; metabolic activity was promoted and cell apoptosis was inhibited in the AD neuronal model. In addition, PF-MF exposure significantly inhibited the expression of Caspase8, Caspase3, and CytC, but increased the Bcl-2/Bax ratio of the AD neuronal model. Meanwhile, PF-MF seemed to have no effect on the expression of Fas and TNFR1. This study indicated that the mitochondria/caspase-dependent apoptotic pathway plays an important role in the positive effects of PF-MF on an AD neuronal model. The results suggested that PF-MF exposure might have potential therapeutic value for AD, and the underling molecular mechanisms still need further studies.

Mechanism and significance of apoptosis of the immortalized human oral mucosal epithelial cells established by Lentivirus-mediated hTERT

During the transition from human oral mucosal epithelial cells (HOMEC) to oral squamous cell carcinoma cells (Cal27), the cells must have undergone a precancerous state. To explore the malignant rule of HOMEC, plv-HOMEC was used as a model cell for the precancerous state to investigate plv-HOMEC's apoptosis by comparing human oral mucosal epithelial cells established by Lentivirus-mediated hTERT (plv-HOMEC) with HOMEC and human Cal27. The lentiviral particles overexpressing hTERT were packaged and transfected into primary HOMEC to obtain plv-HOMEC. Expression levels of NF-κB were detected in the cytoplasm and nucleus of Cal27, plv-HOMEC and HOMEC. The level of intracellular reactive oxygen species was measured to verify the endoplasmic reticulum pathway, cytochrome C expression was detected to verify the mitochondrial pathway, and FasL gene expression was detected to verify the death receptor apoptosis pathway. The total expression of NF-κB in plv-HOMEC increased, mainly due to the greater nuclear import of NF-κB, but it was still much lower than Cal27. The endoplasmic reticulum apoptosis pathway of plv-HOMEC was not significantly affected, and there were no significant differences between them and the HOMEC cells; the mitochondrial apoptosis pathway of plv-HOMEC was inhibited, and the expression of Cyt C was very close to that of Cal27, indicating that the characteristics of plv-HOMEC are so familiar with cancer cells; the death receptor apoptosis pathway of plv-HOMEC was also inhibited, and in this apoptotic pathway, plv-HOMEC were more similar to cancer cells than to HOMEC cells. The present data suggest that NF-κB nucleation may increase in the early stage of healthy cells' carcinogenesis, followed by inhibition of the mitochondrial pathway and the death receptor apoptotic pathway.

Isosamidin from Peucedanum japonicum Roots Prevents Methylglyoxal-Induced Glucotoxicity in Human Umbilical Vein Endothelial Cells via Suppression of ROS-Mediated Bax/Bcl-2

Methylglyoxal (MGO) is a highly reactive metabolite of glucose. Elevated levels of MGO induce the generation of reactive oxygen species (ROS) and cause cell death in endothelial cells. Vascular endothelial cell damage by ROS has been implicated in the progression of diabetic vascular complications, cardiovascular diseases, and atherosclerosis. In this study, the protective effect of isosamidin, isolated from Peucedanum japonicum roots, on MGO-induced apoptosis was investigated using human umbilical vein endothelial cells (HUVECs). Among the 20 compounds isolated from P. japonicum, isosamidin showed the highest effectiveness in inhibiting MGO-induced apoptosis of HUVECs. Pretreatment of HUVECs with isosamidin significantly prevented the generation of ROS and cell death induced by MGO. Isosamidin prevented MGO-induced apoptosis in HUVECs by downregulating the expression of Bax and upregulating the expression of Bcl-2. MGO treatment activated mitogen-activated protein kinases (MAPKs), such as p38, c-Jun N terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). In contrast, pretreatment with isosamidin strongly inhibited the activation of p38 and JNK. Furthermore, isosamidin caused the breakdown of the crosslinks of the MGO-derived advanced glycation end products (AGEs). These findings suggest that isosamidin from P. japonicum may be used as a preventive agent against MGO-mediated endothelial dysfunction in diabetes. However, further study of the therapeutic potential of isosamidin on endothelial dysfunction needs to explored in vivo models.

The beclin 1 interactome: Modification and roles in the pathology of autophagy-related disorders

Beclin 1 a yeast Atg6/VPS30 orthologue has a significant role in autophagy process (Macroautophagy) and protein sorting. The function of beclin 1 depends on the interaction with several autophagy-related genes (Atgs) and other proteins during the autophagy process. The role mediated by beclin 1 is controlled by various conditions and factors. Beclin 1 is regulated at the gene and protein levels by different factors. These regulations could subsequently alter the beclin 1 induced autophagy process. Therefore, it is important to study the components of beclin 1 interactome and factors affecting its expression. Expression of this gene is differentially regulated under different conditions in different cells or tissues. So, the regulation part is important to study as beclin 1 is one of the candidate genes involved in diseases related to autophagy dysfunction. This review focuses on the functions of beclin 1, its interacting partners, regulations at gene and protein level, and the role of beclin 1 interactome in relation to various diseases along with the recent developments in the field.

Effect of Rehabilitation with Extremely Low Frequency Electromagnetic Field on Molecular Mechanism of Apoptosis in Post-Stroke Patients

Apoptosis in acute stroke is associated with a negative prognosis and is correlated with the severity of the neurological deficit. However, there is no evidence that indicates that, in the subacute phase of the stroke, the apoptosis process might activate neuroplasticity. Therefore, in this study, we investigated the effect of an extremely low frequency electromagnetic field (ELF-EMF) on the molecular mechanism of apoptosis, as used in the rehabilitation of post-stroke patients. Patients with moderate stroke severity (n = 48), 3–4 weeks after incident, were enrolled in the analysis and divided into ELF-EMF and non-ELF-EMF group. The rehabilitation program in both groups involves the following: kinesiotherapy—30 min; psychological therapy—15 min; and neurophysiological routines—60 min. Additionally, the ELF-EMF group was exposed to an ELF-EMF (40 Hz, 5 mT). In order to assess the apoptosis gene expression level, we measured the mRNA expression of BAX, BCL-2, CASP8, TNFα, and TP53. We found that ELF-EMF significantly increased the expression of BAX, CASP8, TNFα, and TP53, whereas the BCL-2 mRNA expression after ELF-EMF exposition remained at a comparable level in both groups. Thus, we suggest that increasing the expression of pro-apoptotic genes in post-stroke patients promotes the activation of signaling pathways involved in brain plasticity processes. However, further research is needed to clarify this process.

Bcl-xL inhibits PINK1/Parkin-dependent mitophagy by preventing mitochondrial Parkin accumulation

This report aims to explore how Bcl-xL, a Bcl-2 family protein, regulates PINK1/Parkin-dependent mitophagy. Compared with the Hela cells expressing Parkin alone, co-expression of Bcl-xL significantly inhibited CCCP (Carbonyl cyanide 3- chlorophenylhydrazone)-induced mitochondrial Parkin accumulation and mitophagy. Western blotting analysis illustrated that over-expressed Bcl-xL inhibited CCCP-induced decrease of mitochondrial proteins in Parkin over-expressed cells. Fluorescence loss in photobleaching (FLIP) analyses demonstrated that Bcl-xL inhibited the CCCP-induced translocation of Parkin into mitochondria not by retrotranslocating Parkin from mitochondria to cytoplasm. Fluorescence resonance energy transfer (FRET) imaging revealed in Hela cells that Bcl-xL physically bound with Parkin to form oligomer in cytoplasm, and that Bcl-xL also directly interacted with PINK1 on mitochondria. analysis for HEK293 T cells verified that endogenous Bcl-xL interacted with both endogenous Parkin and PINK1. Collectively, Bcl-xL inhibits PINK1/Parkin- dependent mitophagy by preventing the accumulation of Parkin on mitochondria via two regulation ways: directly binds to Parkin in cytoplasm to prevent the translocation of Parkin from cytoplasm to mitochondria and directly binds to PINK1 on mitochondria to inhibit the Parkin from cytoplasm to mitochondria by PINK1.

Hantavirus inhibits apoptosis by preventing mitochondrial membrane potential loss through up-regulation of the pro-survival factor BCL-2

Hantaviruses, zoonotic RNA viruses belonging to the order Bunyavirales, cause two severe acute diseases in humans, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Hantavirus-infected patients show strong cytotoxic lymphocyte responses and hyperinflammation; however, infected cells remain mostly intact. Hantaviruses were recently shown to inhibit apoptosis in infected cells. By inhibiting granzyme B- and TRAIL-mediated apoptosis, hantaviruses specifically and efficiently inhibit cytotoxic lymphocyte-mediated killing of infected cells. Hantaviruses also strongly inhibit apoptosis triggered intrinsically; i.e., initiated through intracellular activation pathways different from those used by cytotoxic lymphocytes. However, insights into the latter mechanisms are currently largely unknown. Here, we dissected the mechanism behind how hantavirus infection, represented by the HFRS-causing Hantaan virus and the HPS-causing Andes virus, results in resistance to staurosporine-induced apoptosis. Less active caspase-8 and caspase-9, and consequently less active caspase-3, was observed in infected compared to uninfected staurosporine-exposed cells. While staurosporine-exposed uninfected cells showed massive release of pro-apoptotic cytochrome C into the cytosol, this was not observed in infected cells. Further, hantaviruses prevented activation of BAX and mitochondrial outer membrane permeabilization (MOMP). In parallel, a significant increase in levels of the pro-survival factor BCL-2 was observed in hantavirus-infected cells. Importantly, direct inhibition of BCL-2 by the inhibitor ABT-737, as well as silencing of BCL-2 by siRNA, resulted in apoptosis in staurosporine-exposed hantavirus-infected cells. Overall, we here provide a tentative mechanism by which hantaviruses protect infected cells from intrinsic apoptosis at the mitochondrial level by inducing an increased expression of the pro-survival factor BCL-2, thereby preventing MOMPs and subsequent activation of caspases. The variety of mechanisms used by hantaviruses to ensure survival of infected cells likely contribute to the persistent infection in natural hosts and may play a role in immunopathogenesis of HFRS and HPS in humans.

Hantaviruses cause two severe, often fatal, diseases in humans: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS; also called hantavirus cardiopulmonary syndrome (HCPS)). Two hallmarks of human hantavirus infection are robust immune cell activation and hyperinflammation. Despite these strong immune responses, hantavirus-infected cells do not succumb to cell death in patients. Recent studies have shown that hantaviruses hamper cytotoxic lymphocyte-mediated killing, by inhibiting cytotoxic granule-dependent induction of apoptosis and TRAIL-mediated apoptosis, as well as inhibiting intrinsic apoptosis. However, mechanisms behind hantavirus induced inhibition of intrinsic apoptosis have not been described. Here, we show that hantavirus infection leads to increased production of the anti-apoptotic protein BCL-2, hampering the permeabilization of mitochondria and thereby blocking downstream signaling and activation of caspases. Treatment of infected cells with a BCL-2 inhibitor, as well as silencing of BCL-2 with siRNA, both reverted the anti-apoptotic effect. Taken together, this study reveals new insights into the interactions between hantaviruses and infected cells and demonstrates novel mechanisms by which hantaviruses inhibit apoptosis by hampering the permeabilization of mitochondria.

Lotus seedpod proanthocyanidins protect against neurotoxicity after methyl-mercuric chloride injury

In the present study, to investigate the prevention mechanism of proanthocyanidins from lotus seedpod (LSPCs) on methyl mercuric chloride (MMC) induced neurotoxicity, neuron/astrocyte cells were co-cultured to simulate the microenvironment in vivo to the greatest extent. The results showed that, compared with MMC group, pretreatment with LSPCs not only improved cell survival rate, decreased the release of lactate dehydrogenase (LDH), decreased the intracellular reactive oxygen species (ROS) level, and prevented the increase of intracellular [Ca²⁺]i, but also significantly increased the total anti-oxidation capacity (T-AOC) (p＜0.05), the levels of glutathione peroxidase (GSH-Px) (p＜0.05), glutathione (GSH) (p＜0.05), and mitochondrial membrane potential (MMP) (p＜0.01). Besides, LSPCs up-regulated the expression of transcriptional factor Nrf2/HO-1 in a concentration-dependent manner. Moreover, LSPCs reduced the expression of Bax protein, significantly increased the expression of Bcl-xl, Bcl-2, β-Ⅲ-Tubulin, SYN, and Arc proteins. The expression of these proteins is mainly regulated by genes and reflects the changes of genes functions. Taken together, these results suggested that LSPCs could enhance cellular antioxidant defense capacity through regulating the activation of Nrf2/HO-1, and involving the inhibition of mitochondria-mediated apoptotic signaling pathway.

Effect of methionine deficiency on the apoptosis and cell cycle of kidney in broilers

Abundant evidence now supports the idea that methionine deficiency has negative effects on chicken healthy especially in the aspect of cell cycle regulation and apoptosis. But, lacking of knowledge is the evaluation on metabolic organs. To test the effect of methionine deficiency on the kidney, we assessed the apoptosis and the cell cycle of kidney induced by methionine deficiency by the methods of TdT-mediated dUTP Nick-End Labeling (TUNEL), flow cytometry (FCM), quantitative real-time PCR (qRT-PCR) and Enzyme-Linked ImmunoSorbent Assay (ELISA) of chickens for 42 days of age. Our results showed that the number of the apoptotic cells was increased (p < .05 or p < .01), while bcl-2 mRNA expression levels were decreased (p < .05 or p < .01) and bax and caspase-3 mRNA expression levels were higher (p < .01) in methionine deficiency group. Furthermore, the cell cycle results showed a time-dependent increase in G2M phase cells and a corresponding decrease in cells at G2M and S stages, the mRNA expression of p53 and p21 was increased (P < .05 or P < .01) and cyclin B and PCNA was significantly lower (P < .05 or P < .01) in the methionine deficiency group than that of the control group. These findings suggested that methionine deficiency could induce renal apoptosis and cell cycle arrest.

Concomitant targeting of Hedgehog signaling and MCL-1 synergistically induces cell death in Hedgehog-driven cancer cells

In the present study, we show that concomitant inhibition of Hedgehog (HH) signaling by the glioma-associated oncogene homolog1 (GLI1)-targeting agent GANT61 and the antiapoptotic BCL-2 protein family member MCL-1 by A-1210477 synergistically induces cell death in HH-driven cancers, i.e. rhabdomyosarcoma (RMS) and medulloblastoma (MB) cells. Combined genetic and pharmacological inhibition emphasized that co-treatment of GANT61 and A-1210477 indeed relies on inhibition of GLI1 (by GANT61) and MCL-1 (by A-1210477). Mechanistic studies revealed that A-1210477 triggers the release of BIM from MCL-1 and its shuttling to BCL-x_L and BCL-2. Indeed, BIM proved to be required for GANT61/A-1210477-induced cell death, as genetic silencing of BIM using siRNA significantly rescues cell death upon GANT61/A-1210477 co-treatment. Similarly, genetic silencing of NOXA results in a significant reduction of GANT61/A-1210477-mediated cell death. Also, overexpression of MCL-1 or BCL-2 significantly protects RMS cells from GANT61/A-1210477-triggered cell death. Addition of the pan-caspase inhibitor zVAD.fmk significantly decreases GANT61/A-1210477-stimulated cell demise, indicating apoptotic cell death. In conclusion, GANT61 and A-1210477 synergize to engage mitochondrial apoptosis. These findings provide the rationale for further evaluation of dual inhibition of HH signaling and MCL-1 in HH-driven cancers.

In Vitro Vascular-Protective Effects of a Tilapia By-Product Oligopeptide on Angiotensin II-Induced Hypertensive Endothelial Injury in HUVEC by Nrf2/NF-κB Pathways

Angiotensin II (Ang II) is closely involved in endothelial injury during the development of hypertension. In this study, the protective effects of the tilapia by-product oligopeptide Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) on oxidative stress and endothelial injury in Angiotensin II (Ang II)-stimulated human umbilical vein endothelial cells (HUVEC) were evaluated. LSGYGP dose-dependently suppressed the fluorescence intensities of nitric oxide (NO) and reactive oxygen species (ROS), inhibited the nuclear factor-kappa B (NF-κB) pathway, and reduced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and endothelin-1 (ET-1) expression, as shown by western blot. In addition, it attenuated the expression of gamma-glutamyltransferase (GGT) and heme oxygenase 1 (HO-1), as well as increasing superoxide dismutase (SOD) and glutathione (GSH) expression through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Other experiments revealed that LSGYGP increased the apoptotic inhibition ratio between cleaved-caspase-3/procaspase-3, reduced expressions of pro-apoptotic ratio between Bcl-2/Bax, inhibited phosphorylation of mitogen-activated protein kinases (MAPK), and increased phosphorylation of the serine/threonine kinase (Akt) pathway. Furthermore, LSGYGP significantly decreased Ang II-induced DNA damage in a comet assay, and molecular docking results showed that the steady interaction between LSGYGP with NF-κB may be attributed to hydrogen bonds. These results suggest that this oligopeptide is effective in protecting against Ang II-induced HUVEC injury through the reduction of oxidative stress and alleviating endothelial damage. Thus, it has the potential for the therapeutic treatment of hypertension-associated diseases.

Targeted and effective glioblastoma therapy via aptamer-modified tetrahedral framework nucleic acid-paclitaxel nanoconjugates that can pass the blood brain barrier

Targeted DNA nanoparticles have been identified as one of the most promising nanocarriers in anti-glioma drug delivery. We established a multifunctional nanosystem for targeted glioma therapy. Tetrahedral framework nucleic acid (tFNA), entering U87MG cells and bEnd.3 cells, was chosen to deliver two aptamers, GMT8 and Gint4.T, and paclitaxel. GMT8 and Gint4.T, which specifically bind with U87MG cells and with PDGFRβ, were linked with tFNA, to form Gint4.T-tFNA-GMT8 (GTG). GTG was efficiently internalized by U87MG and bEnd.3 cells and penetrated an in-vitro blood-brain-barrier model. GTG loaded with paclitaxel (GPC) had potentiated anti-glioma efficacy. It inhibited the proliferation, migration, and invasion of U87MG cells, and enhanced apoptosis induction in these cells. The expression of apoptosis-related proteins was significantly changed after treatment with GPC, confirming apoptosis induction. Our study demonstrated that the combination of GTG and paclitaxel has great potential for glioma treatment and tFNA shows great promise for use in drug delivery.

CKT0353, a novel microtubule targeting agent, overcomes paclitaxel induced resistance in cancer cells

Microtubule targeting agents (MTAs) are extensively used in cancer treatment and many have achieved substantial clinical success. In recent years, targeting microtubules to inhibit cell division has become a widespread pharmaceutical approach for treatment of various cancer types. Nevertheless, the development of multidrug resistance (MDR) in cancer remains a major obstacle for successful application of these agents. Herein, we provided the evidence that CKT0353, α-branched α,β-unsaturated ketone, possesses the capacity to successfully evade the MDR phenotype as an MTA. CKT0353 induced G₂/M phase arrest, delayed cell division via spindle assembly checkpoint activation, disrupted the mitotic spindle formation and depolymerized microtubules in human breast, cervix, and colorectal carcinoma cells. Molecular docking analysis revealed that CKT0353 binds at the nocodazole binding domain of β-tubulin. Furthermore, CKT0353 triggered apoptosis via caspase-dependent mechanism. In addition, P-glycoprotein overexpressing colorectal carcinoma cells showed higher sensitivity to this agent when compared to their sensitive counterpart, demonstrating the ability of CKT0353 to overcome this classic MDR mechanism involved in resistance to various MTAs. Taken together, these findings suggest that CKT0353 is an excellent candidate for further optimization as a therapeutic agent against tumors with MDR phenotype.

Loading Auristatin PE onto boron nitride nanotubes and their effects on the apoptosis of Hep G2 cells

Auristatin PE (PE) as an anti-microtubule agent possesses good anticancer activity. However, the poor target effect and strong side effect limit the clinical application of PE. Boron nitride nanotubes (BNNTs) represent an outstanding carrier candidate providing a wise choice for liver-targeted drug delivery. A drug delivery system based on BNNTs and PE (BNNTs-PE) against liver cancer cells was designed and constructed in this study. Firstly, BNNTs were prepared and hydroxylated, subsequently, PE was loaded onto BNNTs by noncovalent conjugation and was stable at neutral pH but released at pH 4.49. It was found that BNNTs-PE demonstrates an enhanced anticancer activity against Hep G2 cells in comparison with free PE. BNNTs-PE kills cancer cells in a manner of mitochondria-mediated apoptosis pathway through reducing the mitochondrial membrane potential, activating caspase cascade. This BNNTs-PE system may be very promising for the treatment of liver cancer in the future.

Liposomal Permeabilization Assay to Study the Functional Interactions of the BCL-2 Family

Apoptosis, a form of programmed cell death that is important for development and homeostasis, is regulated by the BCL-2 family of proteins. Over twenty BCL-2 family members have been classified in three groups based on structural homology and function. The multidomain antiapoptotic proteins promote survival, whereas the multidomain and the BH3-only proapoptotic members induce cell death. Because the interaction among the BCL-2 family members occurs primarily at the mitochondrial outer membrane, biochemical assays using artificial liposomes have been developed to study the functional relationship between these proteins. The liposomal permeabilization assay is a cell-free system that relies on the ability of multidomain pro-apoptotic members to promote membrane permeabilization upon activation. By encapsulating a fluorophore and a quencher into liposomes, the degree of permeabilization can be quantified by the increase in fluorescence intensity as the fluorophore and quencher dissociate. The liposomal permeabilization assay has been used to delineate interactions among BCL-2 family members as well as to characterize peptides, small molecules, and lipids that modulate the function of BCL-2 family of proteins. Here, we describe in detail the permeabilization of liposomes induced by the interaction between BAX and BH3-only activator tBID.

Tri-arginine exosite patch of caspase-6 recruits substrates for hydrolysis

Caspases are cysteine-aspartic proteases involved in the regulation of programmed cell death (apoptosis) and a number of other biological processes. Despite overall similarities in structure and active-site composition, caspases show striking selectivity for particular protein substrates. Exosites are emerging as one of the mechanisms by which caspases can recruit, engage, and orient these substrates for proper hydrolysis. Following computational analyses and database searches for candidate exosites, we utilized site-directed mutagenesis to identify a new exosite in caspase-6 at the hinge between the disordered N-terminal domain (NTD), residues 23-45, and core of the caspase-6 structure. We observed that substitutions of the tri-arginine patch Arg-42-Arg-44 or the R44K cancer-associated mutation in caspase-6 markedly alter its rates of protein substrate hydrolysis. Notably, turnover of protein substrates but not of short peptide substrates was affected by these exosite alterations, underscoring the importance of this region for protein substrate recruitment. Hydrogen-deuterium exchange MS-mediated interrogation of the intrinsic dynamics of these enzymes suggested the presence of a substrate-binding platform encompassed by the NTD and the 240's region (containing residues 236-246), which serves as a general exosite for caspase-6-specific substrate recruitment. In summary, we have identified an exosite on caspase-6 that is critical for protein substrate recognition and turnover and therefore highly relevant for diseases such as cancer in which caspase-6-mediated apoptosis is often disrupted, and in neurodegeneration in which caspase-6 plays a central role.

Biochanin A Induces S Phase Arrest and Apoptosis in Lung Cancer Cells

Lung cancer is among the most common malignancies with a poor 5-year survival rate reaching only 16%. Thus, new effective treatment modalities and drugs are urgently needed for the treatment of this malignancy. In this study, we conducted the first investigation of the effects of Biochanin A on lung cancer and revealed the mechanisms underlying its potential anticancer effects. Biochanin A decreased cell viability in a time-dependent and dose-dependent manner and suppressed colony formation in A549 and 95D cells. In addition, Biochanin A induced S phase arrest and apoptosis and decreased mitochondrial membrane potential (ΔΨm) in A549 and 95D cells in a dose-dependent manner. Our results of subcutaneous xenograft models showed that the growth of Biochanin A group was significantly inhibited compared with that of control groups. Finally, P21, Caspase-3, and Bcl-2 were activated in Biochanin A-treated cells and Biochanin A-treated xenografts which also demonstrated that Biochanin A induced cell cycle arrest and apoptosis in lung cancer cells by regulating expression of cell cycle-related proteins and apoptosis-related proteins. In conclusion, this study suggests that Biochanin A inhibits the proliferation of lung cancer cells and induces cell cycle arrest and apoptosis mainly by regulating cell cycle-related protein expression and activating the Bcl-2 and Caspase-3 pathways, thus suggesting that Biochanin A may be a promising drug to treat lung cancer.

Captopril inhibits calpain‑mediated apoptosis of myocardial cells in diabetic rats and improves cardiac function

To explore the effects of captopril on calpain‑mediated apoptosis of myocardial cells and cardiac function in diabetic rats, 30 adult male Sprague‑Dawley rats were randomly divided into three groups: Negative control (NC group), untreated diabetic rats (DM group) and diabetic rats treated with captopril (Cap group). Diabetes was induced by streptozotocin injection. Captopril was intragastrically administered at a daily dose of 50 mg/kg for 12 weeks; the NC and DM groups received an equivalent volume of saline. After 12 weeks of treatment, left ventricular systolic pressure (LVSP), left ventricular end‑diastolic pressure (LVDEP), maximal rate of left ventricular pressure increase (+dp/dtmax), maximal rate of left ventricular pressure decrease (‑dp/dtmax) and left ventricular mass index (LVMI) were measured. The levels of calpain‑1, calpain‑2, B‑cell lymphoma (Bcl)‑2, Bcl‑2 associated protein X (Bax) and total caspase‑3 were detected in cardiac tissue by western blot analysis. The apoptotic index (AI) was assessed with a terminal deoxynucleotidyl transferase‑mediated dUTP nick‑end labeling assay. The ultrastructure of cardiac tissue was determined by transmission electron microscopy. Compared with the NC group, LVDEP and LVMI were increased, whereas LVSP, +dp/dtmax and ‑dp/dtmax were decreased in the DM group. In the Cap group, LVDEP and LVMI were decreased, whereas LVSP, +dp/dtmax and ‑dp/dtmax were increased compared with the DM group. Bcl‑2 protein expression was decreased, whereas the levels of calpain‑1, calpain‑2, Bax and total caspase‑3 protein were increased in the DM group, compared with the NC group. Cap treatment increased Bcl‑2 protein expression and decreased calpain‑1, calpain‑2, Bax and total caspase‑3 protein expression compared with the DM group. Additionally, the AI was increased in the DM group compared with the NC group, and decreased in the Cap group compared with the DM group. Furthermore, ultrastructural examination demonstrated that myocardial cell injury was reduced in the Cap group compared with the DM group. Therefore, captopril improved myocardial structure and ventricular function, by inhibiting calpain‑1 and calpain‑2 activation, increasing Bcl‑2 expression, reducing Bax expression and subsequently inhibiting caspase‑3‑dependent apoptosis.

DBA-induced caspase-3-dependent apoptosis occurs through mitochondrial translocation of cyt-c in the rat hippocampus

Dibromoacetic acid (DBA), a by-product of disinfection, develops in drinking water during chlorination or ozonation processes. Water intake is the main source of DBA exposure in humans, which is potentially neurotoxic. The present study investigated the neurotoxic effects of DBA by assessing the behavioral and biochemical characteristics of Sprague Dawley rats intragastrically treated with DBA at concentrations of 20, 50 and 125 mg kg^-1 body weight for 28 consecutive days. The results indicated that animal weight gain and food consumption were not significantly affected by DBA. However, shuttle box tests showed increases in mistake frequency and reaction latency between the control and high-dose group. We found significant changes in hippocampal neurons by histomorphological observation. Additionally, biochemical analysis indicated enhanced production of reactive oxygen species (ROS) resulting in disruption of cellular antioxidant defense systems including decreased mitochondrial superoxide dismutase (SOD) activity and release of cytochrome c (cyt-c) from mitochondria into the cytosol, which can induce neuronal apoptosis. Furthermore, the increase of cyt-c in the cytosol enhanced caspase-3 and caspase-9 activity, which was confirmed by poly ADP-ribose polymerase-1 (PARP-1) cleavage to its signature fragment of 85 kDa and decreased levels of protein kinase C-δ (PKC-δ) in the hippocampus. Meanwhile, DBA treatment caused differential modulation of apoptosis-associated proteins and mRNAs for phosphorylated apoptosis signal regulating kinase 1 (p-ASK-1), phosphorylated c-jun N-terminal kinase (p-JNK), cyt-c, Bax, Bcl-2, caspase-9 and cleaved caspase-3 accompanied by DNA damage. Taken together, these data indicate that DBA may induce neurotoxicity via caspase-3-dependent apoptosis involving mitochondrial translocation of cyt-c in the rat hippocampus.

Hedgehog signaling negatively co-regulates BH3-only protein Noxa and TAp73 in TP53-mutated cells

In the present study, we show that pharmacological repression by the Hedgehog (Hh) pathway inhibitor (HPI) GANT61 induces expression of the proapoptotic protein Noxa in TP53-mutated embryonal pediatric tumor cells driven by Hh signaling (i.e. rhabdomyosarcoma (RMS) and medulloblastoma (MB)). Similarly, genetic silencing of Gli1 by siRNA causes increased Noxa mRNA and protein levels, while overexpression of Gli1 results in decreased Noxa expression. Furthermore, TAp73 mRNA and protein levels are increased upon Gli1 knockdown, while Gli1 overexpression reduces TAp73 mRNA and protein levels. However, knockdown of TAp73 fails to block Noxa induction in GANT61-treated cells, suggesting that Noxa is not primarily regulated by TAp73. Interestingly, mRNA levels of the transcription factor EGR1 correlate with those of Noxa and TAp73. Silencing of EGR1 results in decreased Noxa and TAp73 mRNA levels, indicating that EGR1 is involved in regulating transcriptional activity of Noxa and TAp73. These findings suggest that Gli1 represses Noxa and TAp73, possibly via EGR1. These findings could be exploited for the treatment of Hh-driven tumors, e.g. for their sensitization to chemotherapeutic agents.

Primary study on the toxic mechanism of vanadyl trehalose in Kunming mice

It has been shown that vanadyl trehalose could lower blood glucose but show mild toxicity to the stomach and intestine in diabetic Kunming mice. We analysed antioxidant levels, pro-inflammatory cytokine expression, apoptosis factors and intestinal microflora alteration to explore the mechanism of vanadyl trehalose toxicity in Kunming mice. The results revealed that oral administration of vanadyl trehalose at tested dose caused significant changes in oxidative stress factor (MDA levels elevated but SOD and T-AOC decreased), expression of inflammatory factor (IL-1β, COX-2, TNF-α and iNOS increased), and apoptosis factor (Bcl-2/Bax decreased and caspase-3 increased), and intestinal microflora dysbiosis (the number of Enterobacteriaceae and Enterococcus increased and Lactobacillus and Bifidobacterium decreased) relative to the control of Kunming mice. These results suggest that the toxic mechanisms of vanadyl trehalose on the stomach and intestine likely involve activation of the oxidative stress system, increased inflammatory response, promotion of apoptosis and the disruption of the normal intestinal microflora.

Overcoming drug-resistant lung cancer by paclitaxel loaded tetrahedral DNA nanostructures

Drug-loaded tetrahedron DNA nanostructures and their cytotoxic effect on drug-resistant cells have been studied.

Effect of tanshinone IIA on oxidative stress and apoptosis in a rat model of fatty liver

Oxidative stress is a crucial factor associated with fatty liver disease, which raises the possibility of using antioxidants to improve liver steatosis. Tanshinone IIA (TSIIA) is a traditional Chinese medicine that has been reported to have antioxidant effects in vitro. The present study aimed to investigate whether TSIIA possesses antioxidant effects in vivo and whether TSIIA was able to improve liver steatosis. Hence, the ability of TSIIA to protect rats from liver disease was explored, particularly in regard to antioxidant activity. Rats were fed a high-lipid diet for 90 days, causing severe liver steatosis, both morphologically and biochemically. An increase in reactive oxygen species (ROS) in the liver was exhibited in addition to significantly elevated serum lipids and malondialdehyde (MDA). Furthermore, hepatocyte apoptosis was measured by Hoechst staining, reverse transcription-quantitative polymerase chain reaction and western blot analysis and an increase in hepatocyte apoptosis rate was indicated in mice on a high-fat diet. Following intraperitoneal injection of TSIIA (10 mg/kg/day), liver steatosis was significantly inhibited. In rats receiving TSIIA treatment, less ROS were indicated in the liver and significantly decreased levels of MDA (P<0.05) in serum were exhibited, whereas significantly increased activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) were observed (P<0.05 and P<0.01, respectively). In addition, the rate of hepatocyte apoptosis was significantly decreased in the TSIIA group (P<0.01). However, TSIIA elicited no effect on serum lipid profiles. These results suggest that TSIIA attenuates oxidative stress by decreasing ROS and MDA production and enhancing the activity of T-SOD and GSH-PX, which may contribute to the inhibition of apoptosis and amelioration of liver steatosis.