CC-115 Mediates GSDME-Dependent Pyroptosis in Lung Adenocarcinoma Through the Akt/Bax Pathway

Chemotherapeutic agents remain the first-line treatment for solid tumors, including lung cancer, but chemotherapy resistance is hampering global efforts to treat this disease. CC-115 is a novel antitumoral compound used in phase I clinical trials. However, it is unclear whether CC-115 is effective against lung adenocarcinoma (LUAD). In the present study, we found that CC-115 induced lytic cell death in A549 and H1650 tumor cells via swelling of cells and formation of large bubbles on the plasma membrane that closely resembled those typical of pyroptosis, a type of programmed cell death linked to chemotherapy. We demonstrated that CC-115 exerts antitumor effects in LUAD through gasdermin E (GSDME)-mediated pyroptosis by acting as a dual inhibitor of DNA-PK and mTOR. CC-115 can inhibit Akt phosphorylation, impairing its inhibitory effect on Bax, thereby inducing pyroptosis via the Bax-mitochondrial intrinsic pathway. CC-115-induced pyroptosis was abrogated by treatment with the Akt activator SC79 or by depletion of Bax. Importantly, CC-115 significantly upregulated the expression of Bax and GSDME-N in a xenograft mouse model, with a reduction in tumor size. Our results revealed that CC-115 suppresses tumor growth by inducing GSDME-mediated pyroptosis through the Akt/Bax-mitochondrial intrinsic pathway, indicating CC-115 as a promising therapeutic agent for LUAD.

Studying the effect of gene fusion of A and C types capsular synthesizing enzymes and anticancer sequence on inducing the expression of apoptotic BCL-2, BAX, and Caspase-3 genes by Real-time RT-PCR method

Background

Today, uterine cancer is one of the most important causes of death in the world and is one of the major problems in human health. There have been numerous reports of the effect of Streptococcus agalactiae peptide and capsular products against cancer cell lines. Objective: This study aimed to research recombinant peptide CPSA-CPSC-L-ACAN and investigate its apoptotic effect against the HeLa cell line by Real-Time-RT PCR.

Design

In this study confirmation of the recombinant fusion peptide was performed by Western blotting. The effect of cytotoxicity of different concentrations of recombinant fusion peptide against the HeLa cell line was investigated by the MTT technique. The expression of apoptotic genes including BAX, BCL-2, and Caspase-3 in comparison with the GAPDH reference gene before and after exposure to recombinant fusion peptide was measured by Real-Time RT-PCR.

Results

Recombinant fusion peptide at a concentration of 63 μg/ml destroyed 50% of the HeLa cell line in 24 h and cell treatment with this concentration increased gene expression of Caspase-3 genes by 16 times, bax by 6 times and decreased the expression of bcl-2 by 0.176 times.

Conclusions

The results showed that treatment of the HeLa cell line with recombinant fusion peptide induced an apoptotic effect. The recombinant fusion peptide could probably help the medical community as a prophylactic or therapeutic treatment for cervical cancer.

Follicle-innervating Aδ-low threshold mechanoreceptive neurons form receptive fields through homotypic competition

The mammalian somatosensory system is comprised of multiple neuronal populations that form specialized, highly organized sensory endings in the skin. The organization of somatosensory endings is essential to their functions, yet the mechanisms which regulate this organization remain unclear. Using a combination of genetic and molecular labeling approaches, we examined the development of mouse hair follicle-innervating low-threshold mechanoreceptors (LTMRs) and explored competition for innervation targets as a mechanism involved in the patterning of their receptive fields. We show that follicle innervating neurons are present in the skin at birth and that LTMR receptive fields gradually add follicle-innervating endings during the first two postnatal weeks. Using a constitutive Bax knockout to increase the number of neurons in adult animals, we show that two LTMR subtypes have differential responses to an increase in neuronal population size: Aδ-LTMR neurons shrink their receptive fields to accommodate the increased number of neurons innervating the skin, while C-LTMR neurons do not. Our findings suggest that competition for hair follicles to innervate plays a role in the patterning and organization of follicle-innervating LTMR neurons.

A dual-regulation inducible switch system for microRNA detection and cell type-specific gene activation

Rationale: MicroRNAs (miRNAs) play key roles in multiple biological processes, many of which exhibit distinct cell type-specific expression patterns. A miRNA-inducible expression system can be adapted as a signal-on reporter for detecting miRNA activity or as a cell type-specific gene activation tool. However, due to the inhibitory properties of miRNAs on gene expression, few miRNA-inducible expression systems are available, and the available systems are only transcriptional or post-transcriptional regulatory system with obvious leaky expression. Methods: To address this limitation, a miRNA-inducible expression system that can tightly control target gene expression is desirable. Here, by taking advantage of an enhanced LacI repression system and the translational repressor L7Ae, a miRNA-inducible dual transcriptional-translational switch system was designed called the miR-ON-D system. Luciferase activity assay, western blotting, CCK-8 assay and flow cytometry analysis were performed to characterize and validate this system. Results: The results demonstrated that leakage expression was strongly suppressed in the miR-ON-D system. It was also validated that the miR-ON-D system could be used to detect exogenous and endogenous miRNAs in mammalian cells. Moreover, it was shown that the miR-ON-D system could be triggered by cell type-specific miRNAs to regulate the expression of biologically relevant proteins (e.g., p21 and Bax) to achieve cell type-specific reprogramming. Conclusion: This study established a tight miRNA-inducible expression switch system for miRNA detection and cell type-specific gene activation.

Insights into Canine Infertility: Apoptosis in Chronic Asymptomatic Orchitis

Chronic asymptomatic orchitis (CAO) is a common cause of acquired non-obstructive azoospermia in dogs. To understand the impact and mode of action of apoptosis, we investigated TUNEL, Bax, Bcl-2, Fas/Fas ligand, and caspase 3/8/9 in testicular biopsies of CAO-affected dogs and compared the results to undisturbed spermatogenesis in healthy males (CG). TUNEL⁺ cells were significantly increased in CAO, correlating with the disturbance of spermatogenesis. Bcl-2, Bax (p < 0.01 each), caspase 9 (p < 0.05), Fas, caspase 8 (p < 0.01 each), and caspase 3 (p < 0.05) were significantly increased at the mRNA level, whereas FasL expression was downregulated. Cleaved caspase 3 staining was sporadic in CAO but not in CG. Sertoli cells, some peritubular (CAO/CG) and interstitial immune cells (CAO) stained Bcl-2⁺, with significantly more immunopositive cells in both compartments in CAO compared to CG. Bcl-2 and CD20 co-expressing B lymphocytes were encountered interstitially and in CAO occasionally also found intratubally, underlining their contribution to the maintenance of CAO. Our results support the crucial role of the intrinsic and extrinsic apoptotic pathways in the pathophysiology of canine CAO. Autoprotective Bcl-2 expression in Sertoli cells and B lymphocytes seems to be functional, however, thereby also maintaining and promoting the disease by immune cell activation.

Beneficial effects of time and energy restriction diets on the development of experimental acute kidney injury in Rat: Bax/Bcl-2 and histopathological evaluation

People's lifestyles and, especially, their eating habits affect their health and the functioning of the organs in their bodies, including the kidneys. One's diet influences the cells' responses to stressful conditions such as acute kidney injury (AKI). This study aims to determine the preconditioning effects of four different diets: energy restriction (ER) diet, time restriction (TR) eating, intermittent fasting (IF), and high-fat diet (HF) on histopathological indices of the kidney as well as the molecules involved in apoptosis during AKI. Adult male rats underwent ER, TR, IF, and HF diets for eight weeks. Then, AKI was induced, and renal function indices, histopathological indices, and molecules involved in apoptosis were measured. In animals with AKI, urinary albumin excretion, serum urea, creatinine and, Bax/Bcl-2 ratio increased in the kidney, while renal eGFR decreased. ER and TR diets improved renal parameters and prevented an increase in the Bax/Bcl-2 ratio. The IF diet improved renal parameters but had no effect on the Bax/Bcl-2 ratio. On the other hand, the HF diet worsened renal function and increased the Bax/Bcl-2 ratio. Histopathological examination also showed improved kidney conditions in the ER and TR groups and more damage in the HF group. This study demonstrated that ER and TR diets have renoprotective effects on AKI and possibly cause the resistance of kidney cells to damage by reducing the Bax/Bcl-2 ratio and improving apoptotic conditions.

Evening primrose oil attenuates oxidative stress, inflammation, fibrosis, apoptosis, and ultrastructural alterations induced by metanil yellow in the liver of rat: a histological, immunohistochemical, and biochemical study

The food color metanil yellow (Myl) is hazardous to several body systems. Evening primrose oil (EPO) was reported to have anti-inflammatory and anti-oxidant properties. The present work investigated the impact of Myl on the hepatic structure and function of rats and evaluated the protective effect of EPO. Forty adult male rats were divided into four groups: control, EPO (5 g/kg/day), Myl (200 mg/kg/day), and EPO- Myl group. Myl significantly increased liver enzymes, advanced glycation end products (AGE), oxidative stress parameters, pro-inflammatory cytokines, nuclear factor kappa B (NF-κB), and inducible nitric oxide synthase (iNOS). Blood vessels in the liver were dilated and congested, with cellular infiltration around them and associated with fibrosis. The hepatocytes were vacuolated and had dark nuclei. The immunohistochemical expression of iNOS, glial fibrillary acidic protein (GFAP), and Bax was significantly elevated. Ultrastructurally, the hepatocytes showed lipid droplets, irregular condensed nuclei with widened perinuclear space, dilated rER, mitochondria with destructed cristae, and multiple vacuoles. Dilated congested blood sinusoids and collagen fiber bundles were seen between hepatocytes. Interestingly, these alterations were less pronounced in rats co-administrated with EPO and Myl. In conclusion, EPO can protect liver against the toxic effects of Myl due to its anti-inflammatory and anti-oxidant activities.

Evaluation of the effect of nano-encapsulated lactoferrin on the expression of Bak and Bax genes in gastric cancer cell line AGS and study of the molecular docking of lactoferrin with these proteins

lactoferrin (Lf) is a glycoprotein with various biological activities, including antibacterial, antiviral, anti-cancer, etc. In the present study, the effect of different concentrations of nano-encapsulated lactoferrin (NE-Lf) on the expression of Bax and Bak genes was evaluated in stomach cancer cell line AGS using real-time PCR technique and cytotoxicity of NE-Lf on the growth cells as well as the molecular mechanism of these two genes and their proteins in the apoptosis pathway and the relationship between lactoferrin and these proteins were investigated by bioinformatics studies. In the viability test, the results showed that the growth inhibition effect of nano-lactoferrin was greater than lactoferrin in both concentrations, and chitosan had no inhibitory effect on the cells. In concentrations of 250 and 500 µg of NE-Lf Bax gene expression increased by 2.3 and 5 times, respectively, and Bak gene expression increased by 1.94 and 1.74 times, respectively. Statistical analysis showed that there is a significant difference in the relative amount of gene expression between the treatments in both genes (P < 0.05). The binding mode of lactoferrin with Bax and Bak proteins was obtained using docking. According to docking results, the N-lobe region of lactoferrin interacts with the Bax protein, as well as the Bak protein. The results show that lactoferrin, in addition to acting on the gene, interacts with Bax and Bak proteins. Since two proteins are components of apoptosis, lactoferrin can induce apoptosis in this way.

Permissive hypercapnia and hypercapnic hypoxia inhibit signaling pathways of neuronal apoptosis in ischemic/hypoxic rats

INTRODUCTION

In the present study, we aimed to test the hypothesis that hypercapnia, independently and/or in combination with hypoxia, can activate signaling pathways related to the inhibition of proapoptotic (caspase-dependent and caspase-independent) factors and the induction of antiapoptotic factors in facilitating adaptation to hypoxia/ischemia.

MATERIALS AND METHODS

Following exposure to permissive hypercapnia and/or normobaric hypoxia, the degree of apoptosis was evaluated in experimental ischemia models in vivo and in vitro. The percentages of caspase-3, apoptosis-inducing factor (AIF), Bax, and Bcl-2 in astrocytes and neurons derived from male Wistar rats were also calculated. In vitro, cells were subjected to various types of respiratory exposure (hypoxia and/or hypercapnia for 24 or 12 h) as well as further sublethal chemical hypoxia. The percentages of these molecules in nerve cells in the ischemic penumbra of the brain after photothrombotic injury were also calculated.

RESULTS

The degree of apoptosis was found to decrease in ischemic penumbra, mostly due to the hypercapnic component. It was also discovered that the levels of caspase-3, AIF, and Bax decreased in this region, whereas the Bcl-2 levels increased following exposure to hypercapnia and hypercapnic hypoxia.

CONCLUSIONS

This integrative assessment of the rate of apoptosis/necrosis in astrocyte and neuron cultures shows that the combination of hypercapnia and hypoxia resulted in the maximum neuroprotective effect. The levels of apoptosis mediators in astrocyte and neuron cultures were calculated after modeling chemical hypoxia in vitro. These results show that the exposure models where permissive hypercapnia and normobaric hypoxia were combined also had the most pronounced inhibitory effects on apoptotic signaling pathways.

Role of ATP5G3 in sodium nitroprusside-induced cell death in cervical carcinoma cells

We identified a gene, subunit C3 (ATP5G3) of mitochondrial ATP synthase, that displayed changes in gene expression under oxidative stress. We examined the role of ATP5G3 and its molecular mechanisms in sodium nitroprusside (SNP)-induced cell death using ATP5G3 small interfering RNA (siATP5G3)-transfected HeLa cells. A significant increase in cytotoxicity was observed in the transfected cells treated with SNP, which suggests a protective role of ATP5G3 in SNP-induced cytotoxicity in the cells. The transfected cells treated with photodegraded SNP showed equal cytotoxicity to SNP, and pretreatment with deferoxamine (DFO) completely inhibited this cytotoxicity. Further, cytotoxicity was significantly inhibited by pretreatment with a p38 inhibitor and was accentuated by the p38 activator in cells. Pretreatment with the Bcl-xL inhibitor also significantly accentuated cytotoxicity. The increase in p38 phosphorylation was significantly higher in siATP5G3-transfected cells treated with SNP in immunoblotting, which was inhibited by pretreatment with DFO. The increase in cytotoxicity with siATP5G3 transfection was completely blocked by cotransfection with sip38, and the blocking effect disappeared by cotransfection with additional siBcl-xL, which suggests that the protective role of ATP5G3 is mediated by Bcl-xL via the inhibition of p38 activity. Cytotoxicity was completely blocked by the cotransfection of siATP5G3 with siBax. No change in apoptotic parameters was observed during cytotoxicity. However, pretreatment with lysosomal inhibitors significantly inhibited cytotoxicity and increased p62 protein levels. These findings suggest that ATP5G3 plays a protective role in autophagic cell death/lysosome-associated cell death induced by SNP via the sequential signaling of ROS/p38/Bcl-xL/Bax in HeLa cells.

Direct interaction between mortalin and HIF-1α at the mitochondria inhibits apoptosis by blocking recruitment of Bax

Hypoxia-inducible factor-1, a heterodimer of alpha (HIF-1α) and beta (HIF-1β or ARNT) subunits, is a major regulator of the transcriptional response to hypoxia. However, HIF-1α, the oxygen-regulated subunit, also exerts nontranscriptional functions through interaction with proteins other than ARNT. We have previously shown that the subcellular localization and protein interactions of HIF-1α are controlled by ERK-mediated phosphorylation at Ser641/643. When HIF-1α is modified at these sites, it is nuclear, binds to ARNT, interacts with nucleophosmin 1 (NPM1) and activates transcription of hypoxia-target genes. On the contrary, unmodified HIF-1α is bound by chromosomal region maintenance 1 (CRM1), exits the nucleus and, via its association with mortalin, is targeted to the mitochondria to form an antiapoptotic complex. To further characterize the latter function, recombinant fragments of HIF-1α and mortalin were used for in vitro binding assays and immunoprecipitation experiments to map the respective binding sites and show that their interaction is direct and functional. We could also show that embelin, a natural product and known inhibitor of the mortalin-p53 interaction, also disrupts the mortalin-HIF-1α association and, furthermore, removes unmodified HIF-1α from mitochondria. Mitochondrial dissociation of HIF-1α, either by embelin or overexpression of a HIF-1α peptide harbouring the mortalin binding site, under stress conditions leads to mitochondrial localization of the pro-apoptotic protein B-cell lymphoma 2-associated X protein (Bax) and induction of apoptosis. We suggest that when ERK activity is low under hypoxia, binding of HIF-1α to mortalin inhibits mitochondrial recruitment of Bax and protects cells from apoptotic cell death.

The function of the phytoplasma effector SWP12 depends on the properties of two key amino acids

Phytoplasmas are insect-borne bacterial pathogens capable of secreting effectors into host cells and interfering with host plant defense response processes. Previous studies have found that the Candidatus Phytoplasma tritici effector SWP12 binds to and destabilizes the wheat transcription factor TaWRKY74, increasing wheat susceptibility to phytoplasmas. Here, we used a Nicotiana benthamiana transient expression system to identify two key functional sites of SWP12 and screened a series of truncated mutants and amino acid substitution mutants to determine whether they inhibit Bax-induced cell death. Using a subcellular localization assay and online structure analysis websites, we found that structure rather than intracellular localization probably affects the function of SWP12. D33A and P85H are two inactive substitution mutants, neither of which interacts with TaWRKY74, and P85H does not inhibit Bax-induced cell death, suppress flg22-triggered reactive oxygen species (ROS) bursts, degrade TaWRKY74, or promote phytoplasma accumulation. D33A can weakly suppress Bax-induced cell death and flg22-triggered ROS bursts and degrade a portion of TaWRKY74 and weakly promote phytoplasma accumulation. S53L, CPP, and EPWB are three SWP12 homolog proteins from other phytoplasmas. Sequence analysis revealed that D33 was conserved in these proteins, and they exhibited the same polarity at P85. Transient expression in N. benthamiana showed that these proteins could inhibit Bax-induced cell death and suppress ROS bursts. Our findings clarified that P85 and D33 of SWP12 play critical and minor roles, respectively, in suppressing the plant defense response and that they play a preliminary role in determining the functions of homologous proteins.

Royal jelly protects brain tissue against fluoride-induced damage by activating Bcl-2/NF-κB/caspase-3/caspase-6/Bax and Erk signaling pathways in rats

This study is aimed at determining whether royal jelly (RJ) which has a powerful antioxidant property prevents fluoride-induced brain tissue damage and exploring whether Bcl-2/NF-κB/ and caspase-3/caspase-6/Bax/Erk pathways play a critical role in the neuroprotective effect of RJ. Wistar albino rats were chosen for the study, and they were randomly distributed into six groups: (i) control; (ii) royal jelly; (iii) fluoride-50; (iv) fluoride-100; (v) fluoride-50 + royal jelly; (vi) fluoride-100 + royal jelly. We established fluoride-induced brain tissue damage with 8-week-old male Wistar albino rats by administration of fluoride exposure (either 50 mg/kg or 100 mg/kg bw) through drinking water for 8 weeks. Then, the study duration is for 56 days where the rats were treated with or without RJ (100 mg/kg bw) through oral gavage. The effects of RJ on glutathione (GSH), catalase activity (CAT), and malondialdehyde (MDA) levels were determined via spectrophotometer. Western blot analysis was performed to investigate the effects of royal jelly on the protein expression levels of Bax, caspase-3, caspase-6, Bcl-2, NF-κB, COX-2, and Erk. It was also studied the effects of RJ on histopathological alterations in fluoride-induced damage to the rat brain. As a result, the Bcl-2, NF-κB, and COX-2 protein expression levels were increased in the fluoride-treated (50 and 100 mg/kg) groups but they were decreased significantly by RJ treatment in the brain tissue. Additionally, the protein expression of caspase-3, caspase-6, Bax, and Erk were decreased in fluoride-treated groups and they were significantly increased by RJ treatment compared to the un-treated rats. Our results suggested that RJ prevented fluoride-induced brain tissue damage through anti-antioxidant activities.

Bad is essential for Bcl-xL-enhanced Bax shuttling between mitochondria and cytosol

Although Bcl-xL has been shown to retrotranslocate Bax from mitochondria to cytosol, other studies have found that Bcl-xL also stabilizes the mitochondrial localization of Bax. It is still unclear what causes the difference in Bcl-xL-regulated Bax localization. Bad, a BH3-only protein with a high affinity for Bcl-xL, may play an important role in Bcl-xL-regulated Bax shuttling. Here, we found that Bcl-xL enhanced both translocalization and retrotranslocation of mitochondrial Bax, as evidenced by quantitative co-localization, western blots and fluorescence loss in photobleaching (FLIP) analyses. Notably, Bad knockdown prevented Bcl-xL-mediated Bax retrotranslocation, indicating Bad was essential for this process. Quantitative fluorescence resonance energy transfer (FRET) imaging in living cells and co-immunoprecipitation analyses showed that the interaction of Bcl-xL with Bad was stronger than that with Bax. The Bad mimetic ABT-737 dissociated Bax from Bcl-xL on isolated mitochondria, suggesting that mitochondrial Bax was directly liberated to cytosol due to Bad binding to Bcl-xL. In addition, MK-2206, an Akt inhibitor, decreased Bad phosphorylation while increasing cytosolic Bax proportion. Our data firmly demonstrate a notion that Bad binds to mitochondrial Bcl-xL to release Bax, resulting in retrotranslocation of Bax to cytosol, and that the amount of Bad involved is regulated by Akt signaling.

Expression profile of the proapoptotic protein Bax in the human brain

Bax is a well-known universal proapoptotic protein. Bax protein is detected in almost all human organs, and its expression levels can be correlated with disease progression and therapeutic efficacy in certain settings. Interestingly, increasing evidence has shown that mature neuronal cell death is often not typical apoptosis. Most results on the expression of Bax proteins (predominantly Baxα) in the human brain come from disease-oriented studies, and the data on Bax protein expression in the normal brain are limited and lack consistency due to many variable factors. Here, we analyzed Bax RNA and protein expression data from multiple databases and performed immunostaining of over 80 samples from 25 healthy subjects across 7 different brain regions. We found that Bax protein expression was heterogeneous across brain regions and individual subjects. Both neurons and glial cells, such as astrocytes, could be Bax positive, but Bax positivity appeared to be highly selective, even within the same cell type in the same region. Furthermore, Bax proteins could be localized in the cytosol (evenly spread or concentrated to one region), nucleus or nucleolus depending on the cell type. Such variation and distribution in Bax expression suggest that Bax may function differently in the human brain than in other organs.

C-Terminal p53 Palindromic Tetrapeptide Restores Full Apoptotic Function to Mutant p53 Cancer Cells In Vitro and In Vivo

We previously demonstrated that a synthetic monomer peptide derived from the C-terminus of p53 (aa 361−382) induced preferential apoptosis in mutant p53 malignant cells, but not normal cells. The major problem with the peptide was its short half-life (half-life < 10 min.) due to a random coil topology found in 3D proton NMR spectroscopy studies. To induce secondary/tertiary structures to produce more stability, we developed a peptide modelled after the tetrameric structure of p53 essential for activation of target genes. Starting with the above monomer peptide (aa 361−382), we added the nuclear localization sequence of p53 (aa 353−360) and the end of the C-terminal sequence (aa 383−393), resulting in a monomer spanning aa 353−393. Four monomers were linked by glycine to maximize flexibility and in a palindromic order that mimics p53 tetramer formation with four orthogonal alpha helices, which is required for p53 transactivation of target genes. This is now known as the 4 repeat-palindromic-p53 peptide or (4R-Pal-p53p). We explored two methods for testing the activity of the palindromic tetrapeptide: (1) exogenous peptide with a truncated antennapedia carrier (Ant) and (2) a doxycycline (Dox) inducer for endogenous expression. The exogenous peptide, 4R-Pal-p53p-Ant, contained a His tag at the N-terminal and a truncated 17aa Ant at the C-terminal. Exposure of human breast cancer MB-468 cells and human skin squamous cell cancer cells (both with mutant p53, 273 Arg->His) with purified peptide at 7 µM and 15 µM produced 52% and 75%, cell death, respectively. Comparatively, the monomeric p53 C-terminal peptide-Ant (aa 361−382, termed p53p-Ant), at 15 µM and 30 µM induced 15% and 24% cell death, respectively. Compared to the p53p-Ant, the exogenous 4R-pal-p53p-Ant was over five-fold more potent for inducing apoptosis at an equimolar concentration (15 µM). Endogenous 4R-Pal-p53p expression (without Ant), induced by Dox, resulted in 43% cell death in an engineered MB468 breast cancer stable cell line, while endogenous p53 C-terminal monomeric peptide expression produced no cell death due to rapid peptide degradation. The mechanism of apoptosis from 4R-Pal-p53p involved the extrinsic and intrinsic pathways (FAS, caspase-8, Bax, PUMA) for apoptosis, as well as increasing reactive oxygen species (ROS). All three death pathways were induced from transcriptional/translational activation of pro-apoptotic genes. Additionally, mRNA of p53 target genes (Bax and Fas) increased 14-fold and 18-fold, respectively, implying that the 4R-Pal-p53p restored full apoptotic potential to mutant p53. Monomeric p53p only increased Fas expression without a transcriptional or translational increase in Fas, and other genes and human marrow stem cell studies revealed no toxicity to normal stem cells for granulocytes, erythrocytes, monocytes, and macrophages (CFU-GEMM). Additionally, the peptide specifically targeted pre-malignant and malignant cells with mutant p53 and was not toxic to normal cells with basal levels of WT p53.

Cell-free synthesis and reconstitution of Bax in nanodiscs: Comparison between wild-type Bax and a constitutively active mutant

Bax is a major player in the mitochondrial pathway of apoptosis, by making the Outer Mitochondrial Membrane (OMM) permeable to various apoptogenic factors, including cytochrome c. In order to get further insight into the structure and function of Bax when it is inserted in the OMM, we attempted to reconstitute Bax in nanodiscs. Cell-free protein synthesis in the presence of nanodiscs did not yield Bax-containing nanodiscs, but it provided a simple way to purify full-length Bax without any tag. Purified wild-type Bax (BaxWT) and a constitutively active mutant (BaxP168A) displayed biochemical properties that were in line with previous characterizations following their expression in yeast and human cells followed by their reconstitution into liposomes. Both Bax variants were then reconstituted in nanodiscs. Size exclusion chromatography, dynamic light scattering and transmission electron microscopy showed that nanodiscs formed with BaxP168A were larger than nanodiscs formed with BaxWT. This was consistent with the hypothesis that BaxP168A was reconstituted in nanodiscs as an active oligomer.

Thymoquinone improves folliculogenesis, sexual hormones, gene expression of apoptotic markers and antioxidant enzymes in polycystic ovary syndrome rat model

BACKGROUND

Nowadays, polycystic ovary syndrome (PCOS) is a prevalent cause of infertility affecting women of reproductive age around the world. Thymoquinone is a natural antioxidant, derived from Nigella sativa.

OBJECTIVES

The current study aimed to evaluate the protective effects of thymoquinone on the detrimental effects of PCOS rats induced with letrozole.

METHODS

Thirty-two female rats were randomly divided into four groups: (1) Control, (2) PCOS, (3) PCOS+5 mg/kg thymoquinone and (4) PCOS+10 mg/kg thymoquinone. Thymoquinone was administered every 3 days for 30 days. Ovaries were histopathologically and stereologically examined, and antioxidant and apoptotic enzymes gene expression in ovaries and sex hormones in serum were measured.

RESULTS

The number of unilaminar, multilaminar, antral, and graffian follicles, volume density of corpus luteum (p < 0.01), and GPx1 gene expression in ovaries and level of FSH in the blood increased in both thymoquinone groups when compared to untreated PCOS (p < 0.05). Ovaries in thymoquinone groups showed a significant reduction in the number of atretic follicles, ovary weight and volume, volume density of cortex and ovarian cysts, Bax gene expression (p < 0.01) and Bax/Bcl2 ratio as well as levels of luteinizing hormone (LH), LH/FSH ratio and testosterone (p < 0.05) in the blood of female rats when compared to PCOS group. Administration of thymoquinone restored the most detrimental effects of PCOS on ovaries (p < 0.01) and sexual hormones (p < 0.05) in rats.

CONCLUSIONS

These data suggest that thymoquinone has improved effects on ovarian function in the PCOS rat model. Therefore, thymoquinone might be useful as a protective agent and adjunct treatment in PCOS patients.

Phosphoglycerate mutase 5 initiates inflammation in acute kidney injury by triggering mitochondrial DNA release by dephosphorylating the pro-apoptotic protein Bax

Acute kidney injury (AKI) is a worldwide public health problem characterized by excessive inflammation with no specific therapy in clinic. Inflammation is not only a feature of AKI but also an essential promoter for kidney deterioration. Phosphoglycerate mutase 5 (PGAM5) was up-regulated and positively correlated with kidney dysfunction in human biopsy samples and mouse kidneys with AKI. PGAM5 knockout in mice significantly alleviated ischemia/reperfusion-induced kidney injury, mitochondrial abnormality and production of inflammatory cytokines. Elevated PGAM5 was found to be mainly located in kidney tubular epithelial cells and was also related to inflammatory response. Knockdown of PGAM5 inhibited the hypoxia/reoxygenation-induced cytosolic release of mitochondrial DNA (mtDNA) and binding of mtDNA with the cellular DNA receptor cGAS in cultured cells. cGAS deficiency also attenuated the inflammation and kidney injury in AKI. Mechanistically, as a protein phosphatase, PGAM5 was able to dephosphorylate the pro-apoptotic protein Bax and facilitate its translocation to mitochondrial membranes, and then initiate increased mitochondrial membrane permeability and release of mtDNA. Leaked mtDNA recognized by cGAS then initiated its downstream-coupled STING pathway, a component of the innate immune system that functions to detect the presence of cytosolic DNA. Thus, our results demonstrated mtDNA release induced by PGAM5-mediated Bax dephosphorylation and the activation of cGAS-STING pathway as critical determinants of inflammation and kidney injury. Hence, targeting this axis may be useful for treating AKI.

Bisphenol A enhances apoptosis, fibrosis, and biochemical fluctuations in the liver of adult male rats with possible regression after recovery

Bisphenol A (BPA) is an environmental contaminant that might be harmful. Human exposure to BPA can occur during the fetal and postnatal periods and extends throughout life. This study aimed to estimate the effects of oral administration of BPA on rat liver and assess the possibility of recovery after cessation. Adult male albino rats were orally administered with BPA (50 mg/kg body weight) for 8 weeks, and then one group was left to recover for 4 weeks. Histological, immunohistochemical, biochemical, and quantitative real-time polymerase chain reaction assessments were performed. Loss of hepatic architecture, vascular dilatation congestion, and exudation, as well as cellular vacuolation, fat accumulation, and pyknotic nuclei were detected. Furthermore, inflammatory infiltration, localized metaplasia, and excessive collagen deposition in the portal triad were observed. Expression of Bcl-2-associated X protein and transforming growth factor beta 1 was prominent, denoting apoptosis and fibrosis. After the administration of BPA, serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, cholesterol, triglycerides, and low-density lipoproteins were enhanced. Additionally, total protein, albumin, and high-density lipoproteins decreased. After a recovery for 4 weeks, hepatic cellular and vascular pathologies returned to normal, except for some inflammatory infiltration. Regarding biochemical affection, most of the parameters were directed toward normal during recovery. However, most of them were still significantly different from controls. This explored BPA hepatotoxicity from structural and functional aspects, and the possible spontaneous reversibility was confirmed. However, the precise mechanisms underlying hepatotoxicity or recovery need more in-depth investigations.

Dietary flavonoid carvacrol triggers the apoptosis of human breast cancer MCF-7 cells via the p53/Bax/Bcl-2 axis

Recently, numerous studies have shown that natural compounds such as carvacrol can be used as therapeutic agents for medicinal purposes. Although carvacrol was found to suppress breast cancer cell lines, however, whether the therapeutic effect of carvacrol on breast cancer is caused by increasing the expression of pro-apoptotic genes in the MCF-7 cell line has not been studied. In this research, we investigate the effect of carvacrol on the expression of P53, pro-apoptotic Bax and anti-apoptotic BCL-2 genes in MCF-7 cells. After preparation and cultivation of MCF-7 cells, the IC50 value of carvacrol on the cells was evaluated by MTT assay, and then apoptosis induction was observed in the cell line treated with different concentrations of carvacrol by DAPI staining. To assess the expression level of Bax, P53 and Bcl-2 both in genes and protein levels QPCR method and western blot analysis were used. According to the results of the research, it was determined that the IC50 of carvacrol compound in MCF-7 cells is 305 µM. DAPI staining exhibit apoptosis and morphological changes in treated MCF-7 cells. Real-time PCR assay and western blot showed increasing the Bax and P53 expression and decreasing the expression of the Bcl-2 anti-apoptotic gene and protein. These results showed that carvacrol has cell growth inhibition effects on the MCF-7 cancer cell line. Carvacrol-induced p53-dependent apoptosis, which might be related to the Bax/Bcl-2 associated pathway. These results indicated that carvacrol could be considered suitable for the prevention and treatment of breast cancer.

Acacetin alleviates myocardial ischaemia/reperfusion injury by inhibiting oxidative stress and apoptosis via the Nrf-2/HO-1 pathway

CONTEXT

Acacetin is a natural source of flavonoids with anti-inflammatory and antioxidant effects.

OBJECTIVE

This study determines acacetin's protective effect and mechanism on myocardial ischaemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

Sprague-Dawley rats were divided into sham and I/R injury and treatment with acacetin. Acacetin (10 mg/kg) was subcutaneously injected for 7 days. ECG and echocardiography were conducted to determine arrhythmia and heart function. The pathological characters of the heart were determined with triphenyl tetrazolium chloride staining, Haematoxylin & Eosin staining, and Masson staining. Expression of proteins in infarct tissues was examined with western blots.

RESULTS

Administrated with acacetin in I/R rats significantly reduced the arrhythmia score from 4.90 to 2.50 and the reperfusion arrhythmia score from 3.79 to 1.82 in the vehicle or the acacetin group, respectively. LVEF was improved from 33.5% in the I/R group to 43.7% in the acacetin group, LVFS was increased from 16.4% to 24.5%, LVIDs was decreased from 6.5 to 5.3 mm. The inflammatory cell infiltration, myocardial fibrosis, and collagen 1 and 3 were reduced by acacetin. Acacetin promoted SOD and decreased MDA. In myocardial tissues, the expression level of TLR4 and IL-6 were restrained, and IL-10 was promoted. Apoptotic protein Bax was suppressed, and anti-apoptotic protein Bcl-2 was promoted in the acacetin group. Interestingly, the transcription factor Nrf-2/HO-1 pathway was also reversed by acacetin.

DISCUSSION AND CONCLUSION

Our findings indicated that acacetin has a potential therapeutic effect in clinical application on treating I/R-induced heart injury.

Hesperetin induces apoptosis in A549 cells via the Hsp70‑mediated activation of Bax

Hesperetin, a predominant flavonoid found in citrus fruits, has received considerable attention for its potential anticancer activity through the reduction of cell viability and the induction of apoptosis. Several effector mechanisms have been demonstrated underlying the antitumor properties of hesperetin but its specific mechanisms have not yet been fully elucidated. In the present study, how hesperetin affects the proliferation of A549 cells and the related cell proliferation regulatory mechanisms, were inevstigated. To elucidate the mechanisms underlying the effects of hesperetin on A549 cells, MTT assay, colony formation assay, flow cytometry, immunoblotting, reverse transcription‑quantitative PCR and JC‑1 staining were performed. The data revealed that hesperetin inhibited cell proliferation and induced apoptosis in these cells. Hesperetin also decreased the level of heat shock protein 70 (Hsp70), a negative regulator of the mitochondrial apoptosis pathway, often overexpressed in various cancer cells and suspected to contribute to tumor development. Hesperetin‑induced Hsp70 suppression was associated with reduced cytosolic Bax and increased mitochondrial Bax levels, leading to the enhancement of the mitochondrial apoptotic cascade. The Hsp70 overexpression‑induced reduction in the level of hesperetin‑induced apoptosis provides evidence to hesperetin‑induced apoptosis being mediated by affecting Hsp70. Furthermore, it was demonstrated that hesperetin reduced Hsp70 expression by inducing a proteasome‑mediated degradation via the upregulation of E3‑ligase, C‑terminus of Hsp70‑interacting protein (CHIP). The present study highlighted the importance of the Bax activation‑triggered mitochondria‑mediated pathway for hesperetin‑induced apoptosis and demonstrated a novel mechanism of how Hsp70 played a critical role in the negative regulation of this apoptotic network in cancer cells.

Gold(III) Complexes with Phenanthroline-derivatives Ligands Induce Apoptosis in Human Colorectal and Breast Cancer Cell Lines

Due to their promising effects, gold(III) complexes recently drew increasing attention in the design of new metal-based anticancer therapeutics. Two gold(III) complexes, square-planar [Au(DPP)Cl2]+ - Complex 1 and distorted square-pyramidal [Au(DMP)Cl3] - Complex 2 (where DPP=4,7-diphenyl-1,10-phenanthroline and DMP=2,9-dimethyl-1,10-phenanthroline) were previously synthetized, described and approved as complexes with pronounced cytotoxic effects on colorectal HCT-116 and breast MDA-MB-231 cancer cells. This study investigated the type of cell death by AO/EB double staining, and identification of possible targets responsible for their cytotoxicity, monitored by immunofluorescence and qPCR methods. Both complexes induced apoptosis in all applied concentrations. In the HCT-116 cells apoptosis was activated by external apoptotic pathway, via increase of Fas receptor protein expression and Caspase 8 gene expression. Also, the mitochondrial pathway was triggered by affecting the Bcl-2 members of regulatory proteins and increased caspase 9 protein expression. In MDA-MB-231 cells, apoptosis was initiated from the mitochondria, due to disbalance between expressions of pro- and anti-apoptotic Bcl-2 family members and caspase 9 activation. Complex 1 shows better activity compared to Complex 2, which is in accordance with its structural characteristics. The results deal weighty data about proapoptotic activity of gold(III) complexes and highlighted potential targets for cancer therapy.

Bcl-2 Family Members Bcl-xL and Bax Cooperatively Contribute to Bortezomib Resistance in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive non-Hodgkin lymphoma with poor prognosis, due to the inevitable development of drug resistance. Despite being the first-in-class proteasome inhibitor for relapsed/refractory MCL, resistance to bortezomib (BTZ) in MCL patients remains a major hurdle of effective therapy, and relapse following BTZ is frequent. Understanding the mechanisms underlying BTZ resistance is, therefore, important for improving the clinical outcome and developing novel therapeutic strategies. Here, we established de novo BTZ-resistant human MCL-derived cells with the highest resistance index of 300-fold compared to parental cells. We provided compelling evidence that both Bcl-xL and Bax are key mediators in determining BTZ sensitivity in MCL cells. Overexpression of antiapoptotic Bcl-xL and depletion of proapoptotic Bax cooperatively protected MCL cells against BTZ-induced apoptosis, causing acquired BTZ resistance, likely by tilting the balance of Bcl-2 family proteins toward antiapoptotic signaling. Bioinformatics analyses suggested that high BCL2L1 (encoded Bcl-xL) and low BAX were, in part, associated with poor prognosis of MCL patients, e.g., when combined with low OGT, which regulates cellular O-GlcNAcylation. Our findings support recent strategies in small molecule drug discovery co-targeting antiapoptotic Bcl-2 family proteins using BH3 mimetics and Bax using Bax activators to overcome cancer drug resistance.