Adenosine triphosphate induces activation of caspase-3 in apoptosis of human granulosa-luteal cells

Adipose-Derived Mesenchymal Stem Cell Transplantation in Chemotherapy-Induced Premature Ovarian Insufficiency: the Role of Connexin and Pannexin

In women undergoing chemotherapy, it is inevitable that infertility risk will increase because of impaired reproductive functions. Premature ovarian insufficiency (POI), which occurs as a devastating result of chemotherapy, is the complete depletion or dysfunction of ovarian follicles. Adipose-derived mesenchymal stem cells (ADMSCs) transplantation is among the alternative treatment methods for POI, which currently do not have an effective treatment method. Apoptosis of granulosa cells in POI is seen as the main mechanism of the disease. It is also reported that in addition to molecules directly associated with apoptosis, connexins, and pannexins are also potential effector molecules in apoptosis. The roles of these molecules in POI, which are known to play a role in many important mechanisms in the ovary, are unknown. In this study, it was aimed to analyze the expressions of Connexin43 and Pannexin1, which are thought to be effective in the formation of POI, and to show the relationship between the antiapoptotic effects of ADMSCs transplantation and these molecules in POI. For this purpose, Caspase3, Connexin43, Pannexin1 proteins, and mRNA expressions were analyzed by immunohistochemistry and RT-qPCR, and AMH levels were measured by ELISA. It was determined that Pannexin1, Caspase3 proteins, and mRNA levels increased in the POI, while Pannexin1 and Caspase3 expressions decreased in the ADMSCs treated group. While Connexin43 level decreased in POI, Connexin43 protein and mRNA levels increased in ADMSCs group. Consequently, this study demonstrated for the first time that Connexin43 and Pannexin1 were associated with apoptosis in POI. In addition, it was revealed that ADMSCs transplantation could produce antiapoptotic effects by modulating these molecules.

Tetrahydrobenzimidazole TMQ0153 triggers apoptosis, autophagy and necroptosis crosstalk in chronic myeloid leukemia

By comparing imatinib-sensitive and -resistant chronic myeloid leukemia (CML) cell models, we investigated the molecular mechanisms by which tetrahydrobenzimidazole derivative TMQ0153 triggered caspase-dependent apoptosis at low concentrations accompanied by loss of mitochondrial membrane potential (MMP) and increase of cytosolic free Ca²⁺ levels. Interestingly, at higher concentrations, TMQ0153 induced necroptotic cell death with accumulation of ROS, both preventable by N-acetyl-L-cysteine (NAC) pretreatment. At necroptosis-inducing concentrations, we observed increased ROS and decreased ATP and GSH levels, concomitant with protective autophagy induction. Inhibitors such as bafilomycin A1 (baf-A1) and siRNA against beclin 1 abrogated autophagy, sensitized CML cells against TMQ0153 and enhanced necroptotic cell death. Importantly, TMQ153-induced necrosis led to cell surface exposure of calreticulin (CRT) and ERp57 as well as the release of extracellular ATP and high mobility group box (HMGB1) demonstrating the capacity of this compound to release immunogenic cell death (ICD) markers. We validated the anti-cancer potential of TMQ0153 by in vivo inhibition of K562 microtumor formation in zebrafish. Taken together, our findings provide evidence that cellular stress and redox modulation by TMQ0153 concentration-dependently leads to different cell death modalities including controlled necrosis in CML cell models.

Activation of P2X7 receptors decreases the proliferation of murine luteal cells

Extracellular ATP regulates cellular function in an autocrine or paracrine manner through activating purinergic signalling. Studies have shown that purinergic receptors were expressed in mammalian ovaries and they have been proposed as an intra-ovarian regulatory mechanism. P2X7 was expressed in porcine ovarian theca cells and murine and human ovarian surface epithelium and is involved in ATP-induced apoptotic cell death. However, the role of P2X7 in corpus luteum is still unclear. The aim of this study was to investigate the role of ATP signalling in murine luteal cells and the possible mechanism(s) involved. We found that P2X7 was highly expressed in murine small luteal cells. The agonists of P2X7, ATP and BzATP, inhibited the proliferation of luteal cells. P2X7 antagonist BBG reversed the inhibition induced by ATP and BzATP. Further studies showed that ATP and BzATP inhibited the expression of cell cycle regulators cyclinD2 and cyclinE2. ATP and BzATP also inhibited the p38-mitogen-activated protein kinase (MAPK) signalling pathway. These results reveal that P2X7 receptor activation is involved in corpus luteum formation and function.

Purinergic signaling in the ovary

Adenosine triphosphate (ATP) is released from the cell by multiple mechanisms. The extracellular form of this purine is processed by ectonucleotidases, resulting in a variety of dephosphorylated metabolites that can bind to specific receptors found in the membrane of target cells; such purinergic signaling is important as an autocrine-paracrine intercellular communication system that influences tissue physiology. In this review, we summarize the studies analyzing purinergic activity in the ovary, which can modulate cellular physiology-including sensitivity to gonadotropins-in several ovarian cell types, including the cumulus-cell complex, granulosa cells, theca cells, and the ovarian surface epithelium. These functions support a role for ATP as an important intra-ovarian messenger, and open new lines of research that can improve our understanding of mechanisms regulating ovarian function and the fine-tuning of folliculogenesis.

Cerebral potential biomarkers discovery and metabolic pathways analysis of α-synucleinopathies and the dual effects of Acanthopanax senticosus Harms on central nervous system through metabolomics analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthopanax senticosus Harms (AS), also called "Ciwujia" in Chinese and "Siberian ginseng" in the Siberian Taiga region, is the herb used in traditional medicinal systems of China, Russia, Japan and Korea for the treatment of various nervous and cerebrovascular diseases.

AIM OF THE STUDY

Our pre-study has showed that AS can significantly suppress α-synuclein overexpression and toxicity. Neuronal protein α-synuclein is a key player in the development of neurodegenerative diseases called α-synucleinopathies. Identifying the potential biomarkers related to α-synucleinopathies may facilitate understanding the pathogenesis of the diseases and the safe application of AS in the clinic.

METHODS AND RESULTS

Ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-QTOF-MS) coupled with pattern recognition methods was integrated to examine the cerebral metabolic signature of human α-synuclein transgenic mice and the effects of AS on central nervous system (CNS) in pathology and physiology. Totally, 17 differentially expressed metabolites in wild type (WT) group and 26 in A30P mutant (A30P) group were identified and considered as potential biomarkers. Among them, 11 endogenous metabolites in WT+AS group and 18 in A30P+AS group were involved in the anti-α-synucleinopathies mechanism of AS. However, western blot and metabolomics analysis showed the effects of AS on CNS in physiology were opposite to those in pathology, which may cause potential neurotoxicity.

CONCLUSIONS

This study demonstrated that endogenous metabolites perturbation was involved in the pathogenesis of α-synucleinopathies and AS produced the dual effects on pathological and physiological CNS.

Activation of A2b adenosine receptor regulates ovarian cancer cell growth: involvement of Bax/Bcl-2 and caspase-3

A2b adenosine receptor (A2bAR) acts as a potent regulator of cell growth in various cell lines. The present study was designed to understand the controlling mechanism of A2bAR agonist (NECA)-induced apoptosis in ovarian cancer cells. Real-time PCR and western blotting assays were used to evaluate the gene and protein expression profiles of A2bAR, respectively. MTT assay was used to study the cell proliferation effect of A2bAR agonist (NECA). Detection of apoptosis was conducted using annexin V-FITC/PI staining, caspase-3 activation assay, and the expression of Bax and Bcl-2 proteins analysis. The mitochondrial membrane potential (ΔΨM) was analyzed by employing JC-1 prob. The mRNA and protein expression levels of A2bAR in ovarian cancer cells were detected. NECA significantly reduced cell viability in a dose-dependent manner in OVCAR-3 and Caov-4 cell lines. The growth inhibition effect of NECA was related to the induction of cell apoptosis, which was manifested by annexin V-FITC staining, activation of caspase-3, and loss of mitochondrial membrane potentials (ΔΨm). In addition, downregulation of the regulatory protein Bcl-2 and upregulation of Bax protein by NECA were also observed. These findings demonstrated that NECA induces apoptosis via the mitochondrial signaling pathway. Thus, A2bAR agonists may be a potential agent for induction of apoptosis in ovarian cancer cells.

Adenosine induces cell cycle arrest and apoptosis via cyclinD1/Cdk4 and Bcl-2/Bax pathways in human ovarian cancer cell line OVCAR-3

Adenosine is a regulatory molecule with widespread physiological effects in almost every cells and acts as a potent regulator of cell growth. Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via caspase activation and Bcl-2/Bax pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the OVCAR-3 human ovarian cancer cells. MTT viability, BrdU and cell counting assays were used to study the cell proliferation effect of adenosine in presence of adenosine deaminase inhibitor and the nucleoside transporter inhibitor. Cell cycle analysis, propidium iodide and annexin V staining, caspase-3 activity assay, cyclinD1, Cdk4, Bcl-2 and Bax protein expressions were assessed to detect apoptosis. Adenosine significantly inhibited cell proliferation in a concentration-dependent manner in OVCAR-3 cell line. Adenosine induced cell cycle arrest in G0/G1 phase via Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by Annexin V-FITC staining and increased sub-G1 population. Moreover, down-regulation of Bcl-2 protein expression, up-regulation of Bax protein expression and activation of caspase-3 were observed in response to adenosine treatment. The results of this study suggest that extracellular adenosine induced G1 cell cycle arrest and apoptosis in ovarian cancer cells via cyclinD1/ Cdk4 and Bcl-2/Bax pathways and caspase-3 activation. These data might suggest that adenosine could be used as an agent for the treatment of ovarian cancer.

Inhibition of phosphodiestrase 9 induces cGMP accumulation and apoptosis in human breast cancer cell lines, MCF-7 and MDA-MB-468

OBJECTIVES

Phosphodiesterase 9 (PDE9) is a major isoform of phosphodiesterase hydrolysing cGMP and plays a key role in proliferation of cells, their differentiation and apoptosis, via intracellular cGMP signalling. The study described here was designed to investigate expression, activity and apoptotic effect of PDE9 on human breast cancer cell lines, MCF-7 and MDA-MB-468.

MATERIALS AND METHODS

Activity and expression of PDE9 were examined using colorimetric cyclic nucleotide phosphodiesterase assay and real-time RT-PCR methods respectively; cGMP concentration was also measured. MTT viability test, annexin V-FITC staining, Hoechst 33258 staining and caspase3 activity assay were used to detect apoptosis.

RESULTS

Treatment of both cell lines with BAY 73-6691 lead to reduction in PDE9 mRNA expression, PDE9 cGMP-hydrolytic activity and elevation of the intracellular cGMP response. BAY 73-6691 significantly reduced cell proliferation in a dose- and time-dependent manner and caused marked increase in apoptosis through caspase3 activation.

CONCLUSION

Our results revealed that BAY 73-6691 induced apoptosis in these breast cancer cell lines through the cGMP pathway. These data suggest that BAY 73-6691 could be utilized as an agent in treatment of breast cancer.

Adenosine induces cell-cycle arrest and apoptosis in androgen-dependent and -independent prostate cancer cell lines, LNcap-FGC-10, DU-145, and PC3

BACKGROUND

Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via intrinsic and extrinsic pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the DU-145, PC3, and LNcap-FGC10 human prostate cancer cells.

METHODS

To observe cell viability and proliferation, MTT assay, cell counting, and BrdU assay were carried out in DU-145, PC3, and LNcap-FGC10 cells. Apoptosis was assessed with the analysis of cell cycle, Hoechst 33258 staining, propidium iodide and annexin-V staining, reactive oxygen species (ROS) formation, mitochondrial membrane potential (ΔΨM) measurement, caspase-3 activity assay, Bcl-2 and Bax protein expression. Moreover, the expression of adenosine receptors and the effects of adenosine receptor (A(1) , A(2a) , and A(3) ) antagonists were examined.

RESULT

Adenosine significantly reduced cell proliferation in a dose-dependent manner in DU-145, PC3, and LNcap-FGC10 cell lines. Adenosine induced arrest in the cell-cycle progression in G0/G1 phase through Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by morphological changes and increased sub-G1 population. Furthermore, increase of ROS, loss of MMP, activation of caspase-3, and down-regulation of Bcl-2 expression was observed. A(1) , A(2a) , A(2b) , and A(3) adenosine receptors mRNA are expressed in the cell lines. Moreover, adenosine-induced apoptosis was inhibited by MRS1220, A(3) adenosine receptor antagonist.

CONCLUSION

Our results suggest that adenosine induced apoptosis in prostate cancer cells via the mitochondrial pathway and is related to the adenosine receptors. These data might suggest that adenosine could be used as an agent for the treatment of prostate cancer.

Molecular mechanisms of A3 adenosine receptor-induced G1 cell cycle arrest and apoptosis in androgen-dependent and independent prostate cancer cell lines: involvement of intrinsic pathway

PURPOSE

A3 adenosine receptor has shown several physiological and pathological activities, including cell proliferation and apoptosis in various cancer cell lines. This study is designed to investigate molecular mechanism and apoptotic pathway of A3 adenosine receptor in DU-145, PC3 and LNcap-FGC10 human prostate cancer cells.

METHODS

The expression level of A3 adenosine receptor was examined using real-time RT-PCR. cAMP concentration was also measured. MTT viability, cell counting and BrdU incorporation tests were used to study the cell proliferation effect of IB-MECA. Cell cycle analysis, Annexin V-FITC staining, Hoechst 33258 staining, mitochondrial membrane potential (ΔΨM), caspase-3 activity, Bcl-2 and Bax protein expression were used to detect apoptosis.

RESULT

A3 adenosine receptors mRNAs were detected at different levels. IB-MECA inhibited forskolin-stimulated cAMP. IB-MECA at (1 μM) suppressed cell proliferation and induced G1 cell cycle arrest. Indeed, IB-MECA down-regulated the expression of CDK4, cyclin D1 and up-regulated p53 expression. IB-MECA at (10-100 μM) induced apoptosis. The activity of caspase-3 was also increased. Expression of Bcl-2 was decreased in response to IB-MECA, while the expression of Bax protein was increased. The results showed a significant loss of ΔΨM, in a dose-dependent manner.

CONCLUSION

This study introduces a possible mechanism through A3 adenosine receptor activation. IB-MECA inhibited prostate cancer cells proliferation and induced G1 cell cycle arrest through p53, Cdk4/cyclinD1 pathway. Apoptosis determined by characteristic morphological changes and increased in sub-G1 population. Loss of MMP, activation of caspase-3 and down-regulation of Bcl-2 expression indicated mitochondrial signaling pathway that involved in the apoptosis.

Localization of plasma membrane bound NTPDases in the murine reproductive tract

Extracellular nucleotides might influence aspects of the biology of reproduction in that ATP affects smooth muscle contraction, participates in steroidogenesis and spermatogenesis, and also regulates transepithelial transport, as in oviducts. Activation of cellular nucleotide purinergic receptors is influenced by four plasma membrane-bound members of the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family, namely NTPDase1, NTPDase2, NTPDase3, and NTPDase8 that differ in their ecto-enzymatic properties. The purpose of this study was to characterize the expression profile of the membrane-bound NTPDases in the murine female and male reproductive tracts by immunological techniques (immunolabelling, Western blotting) and by enzymatic assays, in situ and on tissue homogenates. Other than the expected expression on vascular endothelial and smooth muscle cells, NTPDase1 was also detected in Sertoli cells and interstitial macrophages in testes, in ovarian granulosa cells, and in apical cells from epididymal epithelium. NTPDase2 was largely expressed by cells in the connective tissue; NTPDase3 in secretory epithelia, and finally, NTPDase8 was not detected in any of the tissues studied here. In addition, NTPDase6 was putatively detected in Golgi-phase acrosome vesicles of round spermatids. This descriptive study suggests close regulation of extracellular nucleotide levels in the genital tract by NTPDases that may impact specific biological functions.

Progesterone maintains basal intracellular adenosine triphosphate levels and viability of spontaneously immortalized granulosa cells by promoting an interaction between 14-3-3sigma and ATP synthase beta/precursor through a protein kinase G-dependent mechanism

The present studies were designed to 1) describe changes in both the mitochondrial membrane potential and ATP content of spontaneously immortalized granulosa cells as they undergo apoptosis, 2) identify some of the downstream events that are activated by progesterone (P4), and 3) relate these downstream events to changes in mitochondrial function and apoptotic cell death. These studies revealed that in response to serum deprivation, the mitochondrial membrane potential initially hyperpolarizes and ATP content increases. That this increase in ATP is required for apoptosis was demonstrated by the finding that oligomycin inhibited the increase in ATP and apoptosis. Piridoxalphosphate-6-azopeyl-2'-4'-disulfonic acid, an inhibitor of purinergic receptors, which are activated by ATP, also inhibited apoptosis due to serum withdrawal. This study provides additional support for ATP's causative role in apoptosis. Moreover, 8-Br-cGMP, a protein kinase G (PKG) activator, mimicked P4's action, whereas a PKG antagonist, DT-3, attenuated P4's suppressive effect on ATP and apoptosis. Finally, DT-3 treatment was shown to attenuate P4-regulated phosphorylation of 14-3-3sigma and its binding partner, ATP synthasebeta/precursor and the amount of ATP synthasebeta/precursor that bound to 14-3-3sigma. Based on these data, it is proposed that P4 prevents apoptosis in part by activating PKG, which in turn maintains the interaction between ATP synthasebeta/precursor and 14-3-3sigma. In the absence of P4-induced PKG activity, we further propose that some ATP synthasebeta precursor dissociates from 14-3-3sigma, resulting in its activation and incorporation into the ATP synthase complex, which ultimately results in an increase in ATP and apoptosis.

Impairment of the mitochondrial respiratory enzyme activity triggers sequential activation of apoptosis-inducing factor-dependent and caspase-dependent signaling pathways to induce apoptosis after spinal cord injury

The mitochondrion participates in caspase-independent or caspase-dependent apoptotic pathways through the release of apoptosis-inducing factor or cytochrome c. Whether both mitochondrial apoptotic cascades are triggered in the injured spinal cord remains unknown. Here, we demonstrated that neurons, astrocytes and microglia in spinal segments proximal to a complete spinal cord transection underwent two phases of apoptotic cell death. The early phase of high-molecular weight (HMW) DNA fragmentation was associated with nuclear translocation of apoptosis-inducing factor, reduction in mitochondrial respiratory chain enzyme activity and decrease in cellular ATP concentration. The delayed phase of low-molecular weight (LMW) DNA fragmentation was accompanied by cytosolic release of cytochrome c, activation of caspases 9 and 3, and resumption of mitochondrial respiratory functions and ATP contents. Microinfusion of coenzyme Q(10), an electron carrier in mitochondrial respiratory chain, into the epicenter of the transected spinal cord attenuated both phases of induced apoptosis, and reversed the elicited mitochondrial dysfunction, bioenergetic failure, and activation of apoptosis-inducing factor, cytochrome c, or caspases 9 and 3. We conclude that mitochondrial dysfunction after spinal cord transection represents the initiating cellular events that trigger the sequential activation of apoptosis-inducing factor-dependent and caspase-dependent signaling cascades, leading to apoptotic cell death in the injured spinal cord.

Progesterone regulation of human granulosa/luteal cell viability by an RU486-independent mechanism

CONTEXT

Progesterone (P4) inhibits human granulosa/luteal cell apoptosis by an unknown mechanism.

OBJECTIVE

Our objective was to assess the role of the nuclear P4 receptor (PGR) and PGR membrane component 1 (PGRMC1) in mediating P4's antiapoptotic action in human granulosa/luteal cells.

DESIGN, SETTING, AND PATIENTS

In vitro laboratory studies were designed in which human granulosa/luteal cells were harvested from in vitro fertilization patients from 2004-2006.

MAIN OUTCOME MEASURE

Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assays and DNA staining. Protein expression was observed by Western blot and immunocytochemistry.

RESULTS

PGR was detected in 20% of the human granulosa/luteal cells, and 25 and 50 microM RU486 induced at least 70% of the cells to undergo apoptosis. Five micromolar RU486 neither induced apoptosis nor attenuated the antiapoptotic action of 1 microM P4. PGRMC1 and its binding partner, plasminogen activator inhibitor RNA-binding protein-1 (PAIRBP1), were detected in human granulosa/luteal cells. Antibodies to either PGRMC1 or PAIRBP1 completely attenuated P4's action.

CONCLUSIONS

PGR does not exclusively mediate P4's action because 1) 5 microM RU486 should have been able to override the antiapoptotic action of 1 microM P4 because RU486 binds to the PGR at a greater affinity than P4; 2) 25 and 50 microM RU486 induce three to four times more cells to undergo apoptosis than express PGR; 3) P4 must be continuously present to prevent apoptosis, which implies a rapid, possibly membrane-initiated mechanism of action; and 4) expression and blocking antibody studies suggest that PGRMC1 and PAIRBP1 account in part for P4's action in human granulosa/luteal cells.

Molecular mechanisms of adenosine-induced apoptosis in human HepG2 cells

AIM

To investigate effects of adenosine on cell proliferation and apoptosis in human HepG2 cells.

METHODS

HepG2 cells were incubated in the presence of adenosine (0.1-5 mmol/L) for 12-48 h, and the effect of adenosine on cell proliferation was evaluated by using 3-(4,5-dimethyl-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Hoechst 33342 fluorescent staining, dUTP-fluorescein isothiocyanate (FITC) fluorescence and flow cytometric analysis techniques were used to observe cell apoptosis. The effects of adenosine receptor (A1, A2a, A3 and nonspecific receptor) antagonists (8-cpt, DMPX, MRS1191, and theophylline) and an adenosine transporter protein inhibitor (dipyridamole) on adenosine-induced cell apoptosis were observed. Mitochondrial membrane potential was analyzed using DePsipher fluorescent staining, and caspase activity was detected using a Fluorometric assay kit and a fluorescence microplate reader.

RESULTS

Adenosine significantly reduced cell viability in a dose- and time-dependent manner. The cytotoxicity of adenosine was related to the induction of cell apoptosis. Four adenosine receptor antagonists had no effect on cell apoptosis. However, dipyridamole significantly reduced the percentage of adenosine-induced apoptotic cells from 27.3% to 7.1% (P<0.05). At 48 h after treatment, 3 mmol/L adenosine increased caspase-3 activity 3.5-fold; dipyridamole markedly decreased caspase-3 activity 1.6-fold, and decreased apoptotic cell numbers. When HepG2 cells were treated with 3 mmol/L adenosine, mitochondrial membrane potential and the activity of caspase-8 or -9 remained unchanged.

CONCLUSION

Our results suggest that adenosine-induced apoptosis in HepG2 cells is related to intracellular events rather than cell surface receptors, and that a caspase-3 cascade activation is required, which is not mediated via a mitochondrial pathway.