Bcl-2 delays cell cycle through mitochondrial ATP and ROS

Spermidine attenuates monocrotaline-induced pulmonary arterial hypertension in rats by inhibiting purine metabolism and polyamine synthesis-associated vascular remodeling

Ensuring the homeostatic integrity of pulmonary artery endothelial cells (PAECs) is essential for combatting pulmonary arterial hypertension (PAH), as it equips the cells to withstand microenvironmental challenges. Spermidine (SPD), a potent facilitator of autophagy, has been identified as a significant contributor to PAECs function and survival. Despite SPD's observed benefits, a comprehensive understanding of its protective mechanisms has remained elusive. Through an integrated approach combining metabolomics and molecular biology, this study uncovers the molecular pathways employed by SPD in mitigating PAH induced by monocrotaline (MCT) in a Sprague-Dawley rat model. The study demonstrates that SPD administration (5 mg/kg/day) significantly corrects right ventricular impairment and pathological changes in pulmonary tissues following MCT exposure (60 mg/kg). Metabolomic profiling identified a purine metabolism disorder in MCT-treated rats, which SPD effectively normalized, conferring a protective effect against PAH progression. Subsequent in vitro analysis showed that SPD (0.8 mM) reduces oxidative stress and apoptosis in PAECs challenged with Dehydromonocrotaline (MCTP, 50 μM), likely by downregulating purine nucleoside phosphorylase (PNP) and modulating polyamine biosynthesis through alterations in S-adenosylmethionine decarboxylase (AMD1) expression and the subsequent production of decarboxylated S-adenosylmethionine (dcSAM). These findings advocate SPD's dual inhibitory effect on PNP and AMD1 as a novel strategy to conserve cellular ATP and alleviate oxidative injuries, thus providing a foundation for SPD's potential therapeutic application in PAH treatment.

Dual-signal readout sensing of ATP content in single dental pulp stem cells during differentiation via functionalized glass nanopipettes

Adenosine triphosphate (ATP) is regarded as the "energy currency" in living cells, so real-time quantification of content variation of intracellular ATP is highly desired for understanding some important physiological processes. Due to its single-molecule readout ability, nanopipette sensing has emerged as a powerful technique for molecular sensing. In this study, based on the effect of targeting-aptamer binding on ionic current, and fluorescence resonance energy transfer (FRET), we reported a dual-signal readout nanopipette sensing system for monitoring ATP content variation at the subcellular level. In the presence of ATP, the complementary DNA-modified gold nanoparticles (cDNAs-AuNPs) were released from the inner wall of the nanopipette, which leads to sensitive response variations in ionic current rectification and fluorescence intensity. The developed nanopipette sensor was capable of detecting ATP in single cells, and the fluctuation of ATP content in the differentiation of dental pulp stem cells (DPSCs) was further quantified with this method. The study provides a more reliable nanopipette sensing platform due to the introduction of fluorescence readout signals. Significantly, the study of energy fluctuation during cell differentiation from the perspective of energy metabolism is helpful for differentiation regulation and cell therapy.

Porcine cardiac blood - Salvia miltiorrhiza root alleviates cerebral ischemia reperfusion injury by inhibiting oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza Bge. mixed with porcine cardiac blood (PCB-DS) is mainly employed for the treatment of brain ischemia-induced mental disturbances, palpitations and phlegm confusion based on the traditional principle of Menghe medical sect. PCB is the guide to DS and enhances the effect of DS. However, the potential mechanism of PCB-DS preventing cerebral ischemia/reperfusion injury (CIRI) from the perspective of oxidative stress induced cell apoptosis remains unknown.

AIM OF THE STUDY

To investigate the pharmacological activity and molecular mechanism of PCB-DS against CIRI.

MATERIALS AND METHODS

DS samples processed with different methods were prepared and UPLC-Q-TOF-MS/MS was employed for qualitative analysis of the respective processing product. The middle cerebral artery occlusion reperfusion model was then established to investigate the pharmacological activities of PCB-DS. Pathological changes in the rat brain were observed by triphenyl tetrazolium chloride (TTC), hematoxylin-eosin, and TUNEL staining. The levels of IL-6, IL-1β, and TNF-α were detected by ELISA to evaluate the inflammatory damage. Metabolomics of cerebrospinal fluid was further used to explore the potential mechanism of PCB-DS in preventing CIRI. Based on this, the levels of oxidative stress-related lactate dehydrogenase (LDH), reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined. The protein levels of PI3K, AKT, Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9 proteins of the cerebral infarct zone were finally measured by western blotting.

RESULTS

Forty-seven components were identified in four processing products. Compared to DS, the content of total aqueous components in PCB-DS was significantly increased including salvianolic acid B isomer, salvianolic acid D, salvianolic acid F, and salvianolic acid H/I/J. Among the DS, DS processed with wine, DS processed with pig blood, and DS processed with porcine cardiac blood, PCB-DS best alleviated the CIRI through the neurological score, brain infarct volume, brain histopathology and the levels of inflammatory factors in the brain. Twenty-five significant metabolites in the cerebrospinal fluid were screened out between the sham and I/R groups. They were mainly involved in the beta-alanine metabolism, histidine metabolism, and lysine degradation, which indicated that PCB-DS may inhibit oxidative stress-induced apoptosis to achieve treating ischemic stroke. The results of biomedical examination showed that PCB-DS could alleviate oxidative damage, significantly downregulate the expression of Bax, cleaved caspase-3 and cleaved caspase-9, and upregulate the expression of p-PI3K, p-AKT, and Bcl-2.

CONCLUSION

In summary, this study demonstrated that PCB-DS alleviated CIRI and the molecular mechanism may be related to inhibiting the oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway.

Melatonin attenuates bisphenol A-induced colon injury by dual targeting mitochondrial dynamics and Nrf2 antioxidant system via activation of SIRT1/PGC-1α signaling pathway

Industrial advancement has led to an increase in the production and usage of bisphenol A (BPA), thereby resulting in serious environmental pollution problems. BPA ingestion causes multiorgan toxicity. However, the exact mechanism underlying BPA-induced colon damage remains elusive. Moreover, no safe treatment is available to alleviate BPA-induced colon injury. Therefore, the in vivo and in vitro approaches were employed to detect the protective effects of melatonin (MT) on BPA-induced colon injury and to determine the underpinning molecular mechanisms. MT treatment of mice and the colonic epithelial cells NCM460 alleviated BPA-induced colon damage by inhibiting the mitochondrial dynamic imbalance, enhancing mitochondrial respiratory chain (MRC) complexes expression, reducing reactive oxygen species (ROS) production, and suppressing apoptosis and necroptosis. MT upregulated the proteins level of silent information regulator 1 (SIRT1) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), which further increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and the downstream antioxidant target genes heme oxygenase-1 (HO-1) and NAD(P)H quinone redox enzyme-1 (NQO1). Treatment with the SIRT1 inhibitor EX527 effectively reversed the MT-induced upregulation of the aforementioned protein levels. Thus, the MT-activated Sirt1/PGC-1α signaling pathway restored the mitochondrial dynamic balance and activated the Nrf2 antioxidant axis to attenuate BPA-induced colon injury. These results demonstrate that MT supplementation may potentially mitigate BPA toxicity.

In vitro antifungal activity of Shikonin against Candida albicans by inducing cellular apoptosis and necrosis

BACKGROUND

Our previous studies showed that Shikonin (SK) had a strong anti-Candida albican (C. albicans) activity, especially against some fluconazole-resistant strains, which is probably due to the oxidative damage of SK to C. albicans.

METHODS AND RESULTS

In this study, we expanded the antifungal spectrum and evaluate the toxicity of SK. The results indicated that SK also exhibited potent invitro antifungal activities against other pathogenic fungi such as other Candida, Aspergillus, Cryptococcus, and Dermatophytes, but did not display apparent toxicity to the mammalian cells, suggesting that SK is safe to be a potential antifungal drug. Furtherly, we analyze the exact mechanism of SK against C. albicans. We found that SK could induce a series of apoptosis characteristics, including phosphatidylserine externalization, chromatin condensation and fragmentation, decreased cytochrome c oxidase activity as well as caspase activation.

CONCLUSIONS

In summary, this study highlighted the antifungal activity and mechanism of SK against C. albicans, providing a potential therapeutic strategy for C. albicans infection.

HDL-Chitosan Nanoparticles for siRNA Delivery as an SR-B1 Receptor Targeted System

AIMS

High-Density Lipoprotein (HDL) is a complex structure unique to the human body. ApoA-1 protein is a significant structural/functional protein of HDL and provides a natural interaction with the SR-B1 receptors on the cell membrane. The overexpression of the SR-B1 receptor in the membrane of malignant cells suggests that targeting cancer cells can be possible using HDL. The objective of this study was to prepare HDL-conjugated chitosan nanoparticles containing a genetic material that can be used for liver cancer.

METHODS

HDL used in the preparation of the formulations have been obtained by isolating from blood samples taken from healthy volunteers. Bcl-2 siRNA inhibiting BCL-2 oncogene was selected as the genetic material. Chitosan nanoparticles were prepared using the ionic gelation method utilizing low molecular weight chitosan. Physicochemical properties of formulations, transfection efficacy, and cytotoxicity of them on 3T3 and HepG2 cell lines were examined.

RESULTS

The average diameters of the selected formulations were below 250 nm with a positive zeta potential value between +36 ± 0.1 and +34 ± 0.5 mV. All formulations protected Bcl-2 siRNA from enzymatic degradation in the presence of serum. Cellular uptake ratios of particles by HepG2 cells were found to be between 76% and 98%. HDL/chitosan nanoparticles/Bcl-2 siRNA complex was found to be more toxic when compared to chitosan nanoparticles/Bcl-2 siRNA complex and naked Bcl-2 siRNA.

CONCLUSION

According to attained results, the HDL-conjugated chitosan nanoparticles can bring advantages for targeted siRNA delivery to malignant cells that overexpress SR-B1 receptors, such as HepG2.

Identification of bicyclic compounds that act as dual inhibitors of Bcl-2 and Mcl-1

Elevated expression of anti-apoptotic proteins, such as Bcl-2 and Mcl-1 contributes to poor prognosis and resistance to current treatment modalities in multiple cancers. Here, we report the design, synthesis and characterization of benzimidazole chalcone and flavonoid scaffold-derived bicyclic compounds targeting both Bcl-2 and Mcl-1 by optimizing the structural differences in the binding sites of both these proteins. Initial docking screen of Bcl-2 and Mcl-1 with pro-apoptotic protein Bim revealed possible hits with optimal binding energies. All the optimized bicyclic compounds were screened for their in vitro cytotoxic activity against two oral cancer cell lines (AW8507 and AW13516) which express high levels of Bcl-2 and Mcl-1. Compound 4d from the benzimidazole chalcone series and compound 6d from the flavonoid series exhibited significant cytotoxic activity (IC₅₀ 7.12 μM and 17.18 μM, respectively) against AW13516 cell line. Time Resolved-Fluorescence Resonance Energy Transfer (TR-FRET) analysis further demonstrated that compound 4d and compound 6d could effectively inhibit the Bcl-2 and Mcl-1 proteins by displacing their BH3 binding partners. Both compounds exhibited potent activation of canonical pathway of apoptosis evident from appearance of cleaved Caspase-3 and PARP. Further, treatment of oral cancer cells with the inhibitors induced dissociation of the BH3 only protein Bim from Mcl-1 and Bak from Bcl-2 but failed to release Bax from Bcl-xL thereby confirming the nature of compounds as BH3-mimetics selectively targeting Bcl-2 and Mcl-1. Our study thus identifies bicyclic compounds as promising candidates for anti-apoptotic Bcl-2/Mcl-1 dual inhibitors with a potential for further development.

Calotropis gigantea stem bark extracts inhibit liver cancer induced by diethylnitrosamine

Several fractions of Calotropis gigantea extracts have been proposed to have potential anticancer activity in many cancer models. The present study evaluated the anticancer activity of C. gigantea stem bark extracts in liver cancer HepG2 cells and diethylnitrosamine (DEN)-induced primary liver cancer in rats. The carcinogenesis model induced by DEN administration has been widely used to study pathophysiological features and responses in rats that are comparable to those seen in cancer patients. The dichloromethane (CGDCM), ethyl acetate, and water fractions obtained from partitioning crude ethanolic extract were quantitatively analyzed for several groups of secondary metabolites and calactin contents. A combination of C. gigantea stem bark extracts with doxorubicin (DOX) was assessed in this study to demonstrate the enhanced cytotoxic effect to cancer compared to the single administration. The combination of DOX and CGDCM, which had the most potential cytotoxic effect in HepG2 cells when compared to the other three fractions, significantly increased cytotoxicity through the apoptotic effect with increased caspase-3 expression. This combination treatment also reduced ATP levels, implying a correlation between ATP and apoptosis induction. In a rat model of DEN-induced liver cancer, treatment with DOX, C. gigantea at low (CGDCM-L) and high (CGDCM-H) doses, and DOX + CGDCM-H for 4 weeks decreased the progression of liver cancer by lowering the liver weight/body weight ratio and the occurrence of liver hyperplastic nodules, fibrosis, and proliferative cells. The therapeutic applications lowered TNF-α, IL-6, TGF-β, and α-SMA inflammatory cytokines in a similar way, implying that CGDCM had a curative effect against the inflammation-induced liver carcinogenesis produced by DEN exposure. Furthermore, CGDCM and DOX therapy decreased ATP and fatty acid synthesis in rat liver cancer, which was correlated with apoptosis inhibition. CGDCM reduced cleaved caspase-3 expression in liver cancer rats when used alone or in combination with DOX, implying that apoptosis-inducing hepatic carcinogenesis was suppressed. Our results also verified the low toxicity of CGDCM injection on the internal organs of rats. Thus, this research clearly demonstrated a promising, novel anticancer approach that could be applied in future clinical studies of CGDCM and combination therapy.

Melatonin promotes the development of sheep transgenic cloned embryos by protecting donor and recipient cells

The yield efficiency of transgenic animal generation is relatively low[1]. To improve its efficiency has become a priority task for researchers[2]. Melatonin (N-acetyl-5-methoxytryptamine, MT) is a potent-free radical scavenger and antioxidant to protect mitochondria, lipids, protein and DNA from oxidative stress[3]. In this study, we observed that improving the quality of both donor and recipient cells by giving physiological concentration (10^-7 M) of MT significantly increase the sheep transgenic embryo development in the in vitro condition. MT promotes the donor cell viability, proliferation, efficiency of monoclonal formation and the electrotransferring efficiency of fetal fibroblast cells (FFCs). The mechanistic exploration indicates that MT has the capacity for the synchronization of cell division cycle, reduction of cellular oxidative stress, apoptosis, and the increase of mitochondrial number and function. All of these render MT's ability to increase the efficiency of animal transgenic processes such as somatic cell nuclear transfer (SCNT) and electroporation. The outcomes are the increased cleavage rate and blastocyst rate of the transgenic sheep embryos after MT treatment. These beneficial effects of MT on transgenic embryo development are worth to be tested in the in vivo condition in the future.

Discrimination of Invasive Human Skin Tumor Using an Ultrafast ATP-Proton AND-Gate Probe

Cancer cells undergo unscheduled proliferation resulting from dysregulation of the cell cycle, and hence, evaluation in tumor is of keen interest to examine the invasiveness and recurrence of cancer in the lesion. Molecular probes capable of discriminating actively growing tumor from resting ones remain unexplored despite their vast importance. Here, we describe a novel strategy to visualize invasive areas in tumor with a fluorescence probe that implements synergistic fluorescence response toward the slightly acidic environment of tumor and an ATP-abundant nature of actively growing cells. The probe has been designed for ultrafast detection of ATP with high specificity. We demonstrate its utility in visualizing invasive areas in tumor by distinguishing basal cell carcinomas and squamous cell carcinomas at their early stages by two-photon microscopy.

G2/M cell cycle arrest and apoptosis induced by COH-203 in human promyelocytic leukemia HL-60 cells

The combretastatin A-4/oltipraz hybrid (COH), 5-(3-amino-4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-3H-1,2-dithiole-3-one (COH-203) is one of the COH compounds synthesized by our previous study, which has been reported to affect a number of cancer cell lines, such as SGC-7901, KB, HT-1080, HepG2, SMMC-7721 and BEL-7402. The sensitivity of human acute leukemia cell lines to COH-203, and the mechanism underlying its anti-proliferative effects remain unknown, which was investigated in the present study. In the present study, it was demonstrated that COH-203 had notable time- and dose-dependent antiproliferative effects on the human acute promyelocytic leukemia HL-60 cell line. Furthermore, COH-203 treatment resulted in cell cycle arrest at G₂/M phase in a dose-dependent manner, and subsequently induced apoptosis. Western blot analysis revealed that upregulation of cyclin B was associated with G₂/M arrest. In addition, treatment with COH-203 resulted in downregulated expression of Bcl-2. This result revealed that COH-203-induced apoptosis in HL-60 cells may occur via the mitochondrial pathway in a caspase-dependent manner.

A proteomic analysis of Bcl-2 regulation of cell cycle arrest: insight into the mechanisms

B cell lymphoma 2 (Bcl-2) is an important antiapoptotic gene that plays a dual role in the maintenance of the dynamic balance between the survival and death of cancer cells. In our previous study, Bcl-2 was shown to delay the G0/G1 to S phase entry by regulating the mitochondrial metabolic pathways to produce lower levels of adenosine triphosphate (ATP) and reactive oxygen species (ROS). However, the detailed molecular mechanisms or pathways by which Bcl-2 regulates the cell cycle remain unknown. Here, we compared the effects of Bcl-2 overexpression with an empty vector control in the NIH3T3 cell line synchronized by serum starvation, and evaluated the effects using proteomic analysis. The effect of Bcl-2 on cell cycle regulation was detected by monitoring Bcl-2 and p27 expression. The result of subsequent proteomic analysis of Bcl-2 overexpressing cells identified 169 upregulated and 120 downregulated proteins with a 1.5-fold change. These differentially expressed proteins were enriched in a number of signaling pathways predominantly involving the ribosome and oxidative phosphorylation, according to the data of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. These results indicated that Bcl-2 potentially acts at the translation level to influence proteins or enzymes of the respiratory chain or in the ribosome, and thereby regulates the cell cycle. Additionally, differentially expressed proteins involved in oxidative phosphorylation were determined to account for most of the effects of Bcl-2 on the cell cycle mediated by the mitochondrial pathway investigated in our previous study. These results can provide assistance for additional in-depth studies on the regulation of the cell cycle by Bcl-2. The results of the proteomic analysis determined the mechanism of Bcl-2-dependent delay of the cell cycle progression. In summary, the results of this study provide a novel mechanistic basis for identifying the key proteins or pathways for designing and developing precisely targeted cancer drugs.

Targeting Bcl-2 for cancer therapy

Apoptosis deficiency is one of the most important features observed in neoplastic diseases. The Bcl-2 family is composed of a subset of proteins that act as decisive apoptosis regulators. Research and clinical studies have both demonstrated that the hyperactivation of Bcl-2-related anti-apoptotic effects correlates with cancer occurrence, progression and prognosis, also having a role in facilitating the radio- and chemoresistance of various malignancies. Therefore, targeting Bcl-2 inactivation has provided some compelling therapeutic advantages by enhancing apoptotic sensitivity or reversing drug resistance. Therefore, this pharmacological route turned into one of the most promising routes for cancer treatment. This review discusses some of the well-defined and emerging roles of Bcl-2 as well as its potential clinical value in cancer therapeutics.

Cancer cell-selective modulation of mitochondrial respiration and metabolism by potent organogold(iii) dithiocarbamates

Metabolic reprogramming is a key cancer hallmark that has led to the therapeutic targeting of glycolysis. However, agents that target dysfunctional mitochondrial respiration for targeted therapy remains underexplored. We report the synthesis and characterization of ten (10) novel, highly potent organometallic gold(iii) complexes supported by dithiocarbamate ligands as selective inhibitors of mitochondrial respiration. The structure of dithiocarbamates employed dictates the biological stability and cellular cytotoxicity. Most of the compounds exhibit 50% inhibitory concentration (IC50) in the low-micromolar (0.50-2.9 μM) range when tested in a panel of aggressive cancer types with significant selectivity for cancer cells over normal cells. Consequently, there is great interest in the mechanism of action of gold chemotherapeutics, particularly, considering that DNA is not the major target of most gold complexes. We investigate the mechanism of action of representative complexes, 1a and 2a in the recalcitrant triple negative breast cancer (TNBC) cell line, MDA-MB-231. Whole-cell transcriptomics sequencing revealed genes related to three major pathways, namely: cell cycle, organelle fission, and oxidative phosphorylation. 2a irreversibly and rapidly inhibits maximal respiration in TNBC with no effect on normal epithelial cells, implicating mitochondrial OXPHOS as a potential target. Furthermore, the modulation of cyclin dependent kinases and G1 cell cycle arrest induced by these compounds is promising for the treatment of cancer. This work contributes to the need for mitochondrial respiration modulators in biomedical research and outlines a systematic approach to study the mechanism of action of metal-based agents.

Polyphyllin VI Induces Apoptosis and Autophagy via Reactive Oxygen Species Mediated JNK and P38 Activation in Glioma

Background

Polyphyllin VI (PPVI), a bioactive component derived from a traditional Chinese herb Paris polyphylla, exhibits potential antitumor activity against hepatocellular carcinoma, as well as breast and lung cancers. However, its effect on glioma remains unknown.

Methods

Five glioma cell lines (U251, U343, LN229, U87 and HEB) and an animal model were employed in the study. Anti-proliferation effects of PPVI were first determined using CCK-8 cell proliferation and clone formation assays, then reactive oxygen species (ROS), cell cycle progression and apoptosis effects measured by flow cytometry. The effect of PPVI on protein expression was quantified by Western blot analysis.

Results

Data showed that PPVI inhibited the proliferation of glioma cell lines by modulating the G2/M phase. Additionally, incubation of cells with PPVI promoted apoptosis, autophagy, increased accumulation of ROS and activated ROS-modulated JNK and p38 pathways. On the other hand, N-acetyl cysteine, a ROS inhibitor, attenuated PPVI-triggered effects. Furthermore, JNK and p38 inhibitors ameliorated PPVI-triggered autophagy and apoptosis in glioma cells. In vivo assays showed that PPVI inhibited tumor growth of U87 cell line in nude mice.

Conclusion

Overall, these data suggested that PPVI might be an effective therapeutic agent for glioma.

Do genetic polymorphisms of B-cell CLL/lymphoma 2 confer susceptibility to anti-tuberculous therapy-associated drug-induced liver injury?

OBJECTIVES

The aim of this study was to identify the relationship between B-cell CLL/lymphoma 2 (BCL2) polymorphisms and susceptibility to anti-tuberculous therapy-associated drug-induced liver injury (ATT-DILI).

METHODS

A total of 746 tuberculosis (TB) patients were enrolled in this study. Twenty-one selected single nucleotide polymorphisms in BCL2 were analyzed by custom-by-design 2×48-Plex SNPscan kit. The allele and genotype frequencies between patients with and without ATT-DILI were compared using three different genetic models.

RESULTS

A total of 727/746 participants were successfully genotyped, and 112 of them were diagnosed with ATT-DILI. The A allele of rs8085707, G allele of rs76986960, and A allele of rs949037 conferred an increased risk of ATT-DILI, with estimated odd ratios (ORs) of 2.181 (95% confidence interval (CI) 1.345-3.536, p=0.001), 1.983 (95% CI 1.060-3.709, p=0.029), and 1.390 (95% CI 1.032-1.873, p=0.03), respectively. Bonferroni correction indicated that the A allele of rs8085707 was a risk factor for ATT-DILI (Bonferroni correction: p=0.026). The additive model suggested that patients with the AA genotype of rs8085707 had a significantly higher risk of ATT-DILI compared with those with the GG genotype (Bonferroni correction: p=0.036). The influence of BCL2 polymorphisms on clinical characteristics (clinical symptoms, disease subtypes, and laboratory indicators) was also identified.

CONCLUSIONS

This study is novel in suggesting an association between BCL2 polymorphisms and the risk of ATT-DILI.

Mitochondrial respiratory chain dysfunction mediated by ROS is a primary point of fluoride-induced damage in Hepa1-6 cells

To evaluate the mechanism of fluoride (F) mitochondrial toxicity, we cultured Hepa1-6 cells with different F concentrations (0, 1 and 2 mmoL/L) and determined cell pathological morphology, mitochondrial respiratory chain damage and cell cycle change. Results showed that the activities and mRNA expression levels of antioxidant enzymes considerably decreased, whereas the contents of reactive oxygen species (ROS), malondialdehyde (MDA) and nitric oxide (NO) markedly increased. Breakage of mitochondrial cristae and substantial vacuolated mitochondria were observed by transmission electron microscopy. These results indicate the F-induced oxidative damage in Hepa1-6 cells. The enzyme activities of mitochondrial complexes I, II, III and IV were disordered in Hepa1-6 cells treated by excessive F, thereby indicating a remarkable down-regulation. Further research showed that complex subunits also demonstrated the development of disorder, in which the protein expressions levels of NDUFV2 and SDHA were substantially down-regulated, whereas those of CYC1 and COX Ⅳ were markedly up-regulated. Reductions in ATP and mitochondrial membrane potential were detected with the dysfunction of the mitochondrial respiratory chain. The G2/M phase arrest of the cell cycle in Hepa1-6 cells was measured via flow cytometry, and the up-regulated protein expressions of Cyt c, caspase 9, caspase 3 and substantial apoptotic cells were determined. In summary, this study demonstrated that ROS-mediated mitochondrial respiratory chain dysfunction causes F-induced Hepa1-6 cell damage.

Lead-mediated inhibition of lysine acetylation and succinylation causes reproductive injury of the mouse testis during development

Lead (Pb), a widespread heavy metal, may induce serious diseases, particularly male reproductive injury. However, the mechanisms by which Pb induces testicular injury remain unclear. In this paper, we established a mouse model of Pb-induced testicular injury via an intraperitoneal injection of lead chloride at a concentration of 1.5 mg/kg body weight. We confirmed that Pb could induce a series of injuries, including a low litter size, smaller testes, more weak offspring, direct injury, and aberrant spermiogenesis. Our study demonstrated that Pb could inhibit lysine acetylation (Kac) and succinylation (Ksuc) via western blot (WB) and immunofluorescence (IF) analyses. We subsequently separated different germ cells that contained Pre-meiotic spermatogonia (SPG), meiotic spermatocyte (SPC), and round spermatid (RS) into the Pb-treated and control groups and verified that Pb inhibited Kac in SPC, RS, and particularly, during meiosis. Furthermore, our results regarding the inhibition of pyruvate kinase and mitochondrial electron transport chain complex I and II in the Pb-treated groups suggested that Pb may restrain key enzymes to block the TCA cycle and that the low TCA cycle activity could reduce the contents of two important metabolites, acetyl-CoA and succinyl-CoA, to inhibit Kac and Ksuc. Moreover, we examined the influences of the inhibition of Kac and Ksuc on spermiogenesis, which indicated that decreased Kac and Ksuc could impede the replacement of transition proteins in elongating sperm and disorder the distribution of germ cells in the seminiferous tubule. Our research provides novel insights into the mechanisms of Pb reproductive toxicity with respect to lysine acetylation and succinylation.

Enhanced combination cancer therapy using lipid-calcium carbonate/phosphate nanoparticles as a targeted delivery platform

Aim: Melanoma, the most life-threatening skin cancer, requires more effective therapies. Methodology: A new folic acid (FA) receptor-targeted lipid-coated calcium carbonate/phosphate (LCCP) nanoparticle was synthesized, incorporating two often-used therapeutics, cell death siRNA and α-tocopheryl succinate. Results: The nanoparticles were spherical, with an average size of 40 nm. The nanoparticles exhibited a high gene/drug loading efficiency (60%), with folic acid-enhanced cellular uptake. The nanoparticles with both therapeutics enhanced inhibition of B16F0 melanoma cell growth, showing a moderate synergistic effect. The mechanism of the inhibition is associated with induction of cell apoptosis and cell cycle arrest at G1 phase. Conclusion: Our data indicate that lipid-coated calcium carbonate/phosphate nanoparticles are a potential platform for targeted therapy for melanoma.

Calcium signaling and cell cycle: Progression or death

Cytosolic Ca²⁺ concentration levels fluctuate in an ordered manner along the cell cycle, in line with the fact that Ca²⁺ is involved in the regulation of cell proliferation. Cell proliferation should be an error-free process, yet is endangered by mistakes. In fact, a complex network of proteins ensures that cell cycle does not progress until the previous phase has been successfully completed. Occasionally, errors occur during the cell cycle leading to cell cycle arrest. If the error is severe, and the cell cycle checkpoints work perfectly, this results into cellular demise by activation of apoptotic or non-apoptotic cell death programs. Cancer is characterized by deregulated proliferation and resistance against cell death. Ca²⁺ is a central key to these phenomena as it modulates signaling pathways that control oncogenesis and cancer progression. Here, we discuss how Ca²⁺ participates in the exogenous and endogenous signals controlling cell proliferation, as well as in the mechanisms by which cells die if irreparable cell cycle damage occurs. Moreover, we summarize how Ca²⁺ homeostasis remodeling observed in cancer cells contributes to deregulated cell proliferation and resistance to cell death. Finally, we discuss the possibility to target specific components of Ca²⁺ signal pathways to obtain cytostatic or cytotoxic effects.