Adenosine-induced caspase-3 activation by tuning Bcl-XL/DIABLO/IAP expression in HuH-7 human hepatoma cells

Adenosine Signaling in the Tumor Microenvironment

Adenosine, deriving from ATP released by dying cancer cells and then degradated in the tumor environment by CD39/CD73 enzyme axis, is linked to the generation of an immunosuppressed niche favoring the onset of neoplasia. Signals delivered by extracellular adenosine are detected and transduced by G-protein-coupled cell surface receptors, classified into four subtypes: A₁, A_2A, A_2B, and A₃. A critical role of this nucleoside is emerging in the modulation of several immune and nonimmune cells defining the tumor microenvironment, providing novel insights about the development of novel therapeutic strategies aimed at undermining the immune-privileged sites where cancer cells grow and proliferate.

Therapeutic potency of pharmacological adenosine receptors agonist/antagonist on cancer cell apoptosis in tumor microenvironment, current status, and perspectives

The hypoxic niche of tumor leads to a tremendous increase in the extracellular adenosine concentration through alteration of adenosine metabolism in the tumor microenvironment (TME). This consequently affects cancer progression, local immune responses, and apoptosis of tumor cells. Regulatory effect of adenosine on apoptosis in TME depends on the cancer cell type, pharmacological characteristics of adenosine receptor subtypes, and the adenosine concentration in the tumor niche. Exploiting specific pharmacological adenosine receptor agonist and antagonist inducing apoptosis in cancer cells can be considered as a proper procedure to control cancer progression. This review summarizes the regulatory role of adenosine in cancer cell apoptosis for a better understanding, and hence better management of the disease.

Investigation of the neuroprotective effects of Lycium barbarum water extract in apoptotic cells and Alzheimer's disease mice

Alzheimer's disease (AD) affects people worldwide and is caused by chronic and progressive damage to the central nervous system. Lycium barbarum (LB), a renowned functional food and medicinal plant in Southeast Asia, may possess protective effects against nerve injury. The present study aimed to investigate the neuroprotective effects of LB water extract in a differentiated (D)PC12 cellular apoptosis model induced by L-glutamic acid (L-Glu), and a mouse model of AD, induced by the combination of AlCl₃ and D-galactose. LB markedly increased DPC12 cell survival against L-Glu induced damage by increasing cell viability, reducing the apoptosis rate and G1 phase arrest, suppressing intracellular reactive oxygen species accumulation, blocking Ca²⁺ overload and preventing mitochondrial membrane potential depolarization. LB additionally normalized the expression levels of apoptosis regulator Bcl-2, apoptosis regulator BAX, and cleaved caspase-3, −8 and −9 in L-Glu exposed cells. In the AD mouse model, LB increased the amount of horizontal and vertical movement in the autonomic activity test, improved endurance time in the rotarod test and decreased escape latency time in the Morris water maze test. Additionally, the levels of acetylcholine and choline acetyltransferase were significantly increased in the serum and hypothalamus in the LB-treated AD mice. These data suggested that LB may exert neuroprotective effects and may aid in preventing neurodegenerative disease.

Dipyridamole reduces penile apoptosis in a rat model of post-prostatectomy erectile dysfunction

Purpose:

Despite the nerve-sparing technique, many patients suffer from erectile dysfunction after radical prostatectomy (RP) due to cavernous nerve injury. The aim of this study was to evaluate dipyridamole as a potential treatment agent of post-radical prostatectomy erectile dysfunction.

Material and methods:

A total of 18 male Sprague-Dawley rats were randomized into three experimental Groups (SHAM+DMSO, BCNI+DMSO and BCNI+DIP). An animal model of bilateral cavernous nerve crush injury (BCNI) was established to mimic the partial nerve damage during nerve-sparing RP. After creating of BCNI, dimethyl sulphoxide (DMSO) was administered transperitoneally as a vehicle to SHAM+DMSO and BCNI+DMSO Groups. BCNI+DIP Group received dipyiridamole (10mg/kg/day) as a solution in DMSO for 15 days. Afterwards, rats were evaluated for in vivo erectile response to cavernous nerve stimulation. Penile tissues were also analyzed biochemically for transforming growth factor-β1 (TGF-β1) level. Penile corporal apoptosis was determined by TUNEL method.

Results:

Erectile response was decreased in rats with BCNI and there was no significant improvement with dipyridamole treatment. TGF-β1 levels were increased in rats with BCNI and decreased with dipyridamole treatment. Dipyridamole led to reduced penile apoptosis in rats with BCNI and there was no significant difference when compared to sham operated rats.

Conclusions:

Although fifteen-day dipyridamole treatment has failed to improve erectile function in rats with BCNI, the decline in both TGF-β1 levels and apoptotic indices with treatment may be helpful in protecting penile morphology after cavernous nerve injury.

Medical perspective in testicular ischemia-reperfusion injury

Testicular torsion or torsion of the spermatic cord is one of the most serious urological conditions. It causes testicular injury, which potentially leads to male subfertility. The turning of the spermatic cord and spermatic structures around themselves results in biochemical and histological changes; however, following testicular detorsion, tissues undergo reperfusion that causes more severe damage than that induced by ischemia. Since the primary causes of testicular damage are reactive oxygen species production, an increase in intra-mitochondrial calcium concentration and an increased rate of cellular apoptosis, different medications may potentially be effective. It seems that several medications, experimentally and sometimes clinically, serve an adjuvant role in the cellular damage that occurs following ischemia-reperfusion. Antioxidants, calcium channel blockers, phytotherapeutical medicinals, anaesthetics, hormones and platelet inhibitors may potentially create a solid basis for an adjuvant restoring therapy and ameliorate testicular function following torsion. The current study aimed to review the relevant literature and discuss the actions of a number of molecules that may protect the testes during ischemia/reperfusion injury.

Anticancer effect of adenosine on gastric cancer via diverse signaling pathways

Extracellular adenosine induces apoptosis in a variety of cancer cells via intrinsic and extrinsic pathways. In the former pathway, adenosine uptake into cells triggers apoptosis, and in the latter pathway, adenosine receptors mediate apoptosis. Extracellular adenosine also induces apoptosis of gastric cancer cells. Extracellular adenosine is transported into cells through an adenosine transporter and converted to AMP by adenosine kinase. In turn, AMP activates AMP-activated protein kinase (AMPK). AMPK is the factor responsible for caspase-independent apoptosis of GT3-TKB gastric cancer cells. Extracellular adenosine, on the other hand, induces caspase-dependent apoptosis of MKN28 and MKN45 gastric cancer cells by two mechanisms. Firstly, AMP, converted from intracellularly transported adenosine, initiates apoptosis, regardless of AMPK. Secondly, the A₃ adenosine receptor, linked to G_i/G_q proteins, mediates apoptosis by activating the G_q protein effector, phospholipase Cγ, to produce inositol 1,4,5-trisphosphate and diacylglycerol, which activate protein kinase C. Consequently, the mechanisms underlying adenosine-induced apoptosis vary, depending upon gastric cancer cell types. Understand the contribution of each downstream target molecule of adenosine to apoptosis induction may aid the establishment of tailor-made chemotherapy for gastric cancer.

Immunity, inflammation and cancer: a leading role for adenosine

Cancer is a complex disease that is dictated by both cancer cell-intrinsic and cell-extrinsic processes. Adenosine is an ancient extracellular signalling molecule that can regulate almost all aspects of tissue function. As such, several studies have recently highlighted a crucial role for adenosine signalling in regulating the various aspects of cell-intrinsic and cell-extrinsic processes of cancer development. This Review critically discusses the role of adenosine and its receptors in regulating the complex interplay among immune, inflammatory, endothelial and cancer cells during the course of neoplastic disease.

A Module Analysis Approach to Investigate Molecular Mechanism of TCM Formula: A Trial on Shu-feng-jie-du Formula

At the molecular level, it is acknowledged that a TCM formula is often a complex system, which challenges researchers to fully understand its underlying pharmacological action. However, module detection technique developed from complex network provides new insight into systematic investigation of the mode of action of a TCM formula from the molecule perspective. We here proposed a computational approach integrating the module detection technique into a 2-class heterogeneous network (2-HN) which models the complex pharmacological system of a TCM formula. This approach takes three steps: construction of a 2-HN, identification of primary pharmacological units, and pathway analysis. We employed this approach to study Shu-feng-jie-du (SHU) formula, which aimed at discovering its molecular mechanism in defending against influenza infection. Actually, four primary pharmacological units were identified from the 2-HN for SHU formula and further analysis revealed numbers of biological pathways modulated by the four pharmacological units. 24 out of 40 enriched pathways that were ranked in top 10 corresponding to each of the four pharmacological units were found to be involved in the process of influenza infection. Therefore, this approach is capable of uncovering the mode of action underlying a TCM formula via module analysis.

[Characteristic genomics of peripheral blood mononuclear cells of hepatocellular carcinoma patients with liver-kidney yin deficiency syndrome]

OBJECTIVE

To explore the characteristic genomics of syndrome of liver-kidney yin deficiency in peripheral blood mononuclear cells of hepatocellular carcinoma (HCC) patients.

METHODS

HCC patients with or without syndrome of liver-kidney yin deficiency were enrolled into the experimental group and the control group, respectively; their gene expression profiles were evaluated by a whole-genome Affymetrix GeneChip Human Genome U133 Plus 2.0 Array. The differentially expressed mRNAs were then selected by Gene Ontology (GO) and pathway analyses, respectively. Based on the results of GO and pathway analyses, gene coexpression networks were built according to the normalized signal intensity of specifically expressed genes. Finally, the results from microarray were confirmed by real-time fluorescence quantitative polymerase chain reaction and Western blot methods.

RESULTS

The results showed that a set of 615 mRNAs were differentially expressed in the HCC patients with syndrome of liver-kidney yin deficiency. By GO enrichment analysis, the genes for anti-apoptosis, regulation of cell cycle, transmembrane transport, etc. were up-regulated or down-regulated in the experimental group. Another functional analysis of mRNAs by KEGG revealed that 10 signal transduction pathways were up-regulated and 16 were down-regulated, such as antigen processing and presentation, cell cycle, and protein export. Based on the above results, we constructed coexpression networks to determine which genes may play pivotal role in HCC patients with syndrome of liver-kidney yin deficiency. Some critical genes, including SEC62 (SEC62 homolog (S. cerevisiae)), CCNB1 (cyclin B1) and BIRC3 (baculoviral IAP repeat-containing 3), which rank the top 3 in |δ normalized degree| were chosen. Of another 60 samples, we found that the mRNA expressions of SEC62, CCNB1 and BIRC3 were significantly lower in HCC patients with syndrome of liver-kidney yin deficiency than those without syndrome of liver-kidney yin deficiency (P<0.01). Also, the protein expressions of SEC62, CCNB1 and BIRC3 were significantly lower (P<0.01).

CONCLUSION

Gene chip technique allows rapid and high-throughput screening for different gene expression in HCC patients with or without liver-kidney yin deficiency syndrome. The results of this study further confirm the hypothesis on the essence of syndrome, namely, a kind of deviation from the normal state in multigene style on the levels of both mRNA and protein.

A(3) adenosine receptor mediates apoptosis in 5637 human bladder cancer cells by G(q) protein/PKC-dependent AIF upregulation

BACKGROUND/AIMS

A(3) adenosine receptor mediates apoptosis in a variety of cancer cells via diverse signaling pathways. The present study was conducted to assess A(3) adenosine receptor-mediated apoptosis in human bladder cancer cell lines and to understand the underlying mechanism.

METHODS

Human bladder cancer cell lines such as 253J, 5637, KK-47, TCCSUP, T24, and UMUC-3 cells were cultured. The siRNA to silence the A(3) adenosine receptor-targeted gene was constructed and transfected into cells. MTT assay, TUNEL staining, Western blotting, and real-time RT-PCR were carried out.

RESULTS

For all the investigated cell types adenosine induced apoptosis in a concentration (0.01-10 mM)- and treatment time (24-48 h)-dependent manner. Adenosine-induced 5637 cell death was significantly inhibited by the A(3) adenosine receptor inhibitor MRS1191 or knocking-down A(3) adenosine receptor, and the A(3) adenosine receptor agonist 2-Cl-IB-MECA mimicked the adenosine effect. The adenosine effect was prevented by GF109203X, an inhibitor of protein kinase C (PKC), but it was not affected by forskolin, an activator of adenylate cyclase. Adenosine-induced 5637 cell death, alternatively, was not inhibited by the pan-caspase inhibitor Z-VAD. Adenosine upregulated expression of apoptosis-inducing factor (AIF), that is suppressed by knocking-down A(3) adenosine receptor, and accumulated AIF in the nucleus.

CONCLUSION

The results of the present study show that adenosine induces 5637 cell apoptosis by upregulating AIF expression via an A(3) adenosine receptor-mediated G(q) protein/PKC pathway.

Comparison of the protective effect of dipyridamole and acetylsalicylic acid on long-term histologic damage in a rat model of testicular ischemia-reperfusion injury

PURPOSE

Ischemia reperfusion injury arising from testicular torsion results in a loss of spermatogenesis and a significant increase in germ cell apoptosis. We investigated the effects of dipyridamole and acetylsalicylic acid (ASA), 2 well-known platelet inhibitors, on testicular ischemia reperfusion injury.

METHODS

Thirty adult male Sprague-Dawley rats were randomly divided into 5 groups (n = 6 for each group): control, sham-operated, torsion/detorsion (T/D), T/D + dipyridamole, and T/D + ASA. Testicular ischemia was achieved by rotating the left testis 720° clockwise for 2 hours. Thirty minutes before torsion, 10 mg/kg dipyridamole was injected transperitoneally in the T/D + dipyridamole group, and 100 mg/kg ASA was injected transperitoneally in the T/D + ASA group. Sixty days after the initial surgical procedure, ipsilateral orchiectomies were performed for histopathologic examination to determine Johnsen's mean testicular biopsy score (MTBS), mean seminiferous tubular diameter (MSTD), and apoptotic index (AI) in all groups.

RESULTS

Unilateral testicular torsion-detorsion led to a significant decrease in Johnsen's MTBS and MSTD values in the ipsilateral testis and a significant increase in AI values of the T/D group. There were no significant differences between the T/D + dipyridamole and control groups in terms of MSTD and MTBS values. Although an amount of improvement exits in T/D + ASA group, there were significant differences between the T/D + ASA and control group MSTD and MTBS values. There was no significant difference between the T/D + dipyridamole and control groups in terms of AI values (P > .05), but the differences between the T/D + ASA and control groups were significant despite a slight decline in AI values of the T/D + ASA group.

CONCLUSIONS

Our findings show that the use of dipyridamole before testicular reperfusion has a potentially protective effect against long-term injury in testicular ischemia reperfusion injury.

Intracellularly transported adenosine induces apoptosis in [corrected] MCF-7 human breast cancer cells by accumulating AMID in the nucleus

Extracellular adenosine induced apoptosis of MCF-7 human breast cancer cells in a concentration (10μM-10mM)- and treatment time (24-72h)-dependent manner, and the effect was inhibited by the adenosine transporter inhibitor dipyridamole, but not an inhibitor of adenosine kinase, an inhibitor of AMP-activated protein kinase, or inhibitors for A(1), A(2a), A(2b), and A(3) adenosine receptors. No significant activation of caspase-7, -8, or -9 was obtained with adenosine. Adenosine promoted translocation of apoptosis-inducing factor (AIF)-homologous mitochondrion-associated inducer of death (AMID) from the cytosol into the nucleus, although the total amount of AMID was not affected. Adenosine-induced MCF-7 cell death was abrogated by knocking-down AMID. The results of the present study indicate that intracellularly transported adenosine induces MCF-7 cell apoptosis by accumulating AMID in the nucleus in a caspase-independent manner.

Adenosine induces apoptosis in SBC-3 human lung cancer cells through A(3) adenosine receptor-dependent AMID upregulation

BACKGROUND/AIMS

We have shown that A(3) adenosine receptor mediates apoptosis in human lung cancer cells such as A549 cells, an epithelial adenocarcinoma cell line, and Lu-65 cells, a giant cell cancer cell line, via each different signaling pathway. AMID, a pro-apoptotic protein, induces caspase-independent apoptosis by accumulating in the nucleus. The present study investigated AMID-dependent apoptosis through A(3) adenosine receptor in SBC-3 cells, a human small cell lung cancer cell line.

METHODS

MTT assay, TUNEL staining, flow cytometry using propidium iodide and annexin V-FITC, and Western blotting were carried out in SBC-3 cells transfected with and without the siRNA to silence the A(3) adenosine receptor-targeted gene or the AMID-targeted gene.

RESULTS

Adenosine induced SBC-3 cell apoptosis in a concentration (0.01-10 mM) and treatment time (24-72 h)-dependent manner, and a similar effect was obtained with the A(3) adenosine receptor agonist 2-Cl-IB-MECA. Adenosine-induced SBC-3 cell death was inhibited by the A(3) adenosine receptor inhibitor MRS1191, knocking-down A(3) adenosine receptor, or knocking-down AMID. Adenosine upregulated expression of the AMID mRNA and protein in SBC-3 cells, that is suppressed by knocking-down A(3) adenosine receptor. In addition, adenosine increased nuclear AMID localization in concert with decreased cytosolic AMID localization.

CONCLUSION

The results of the present study show that adenosine induces SBC-3 cell apoptosis by upregulating AMID expression and promoting AMID translocation into the nucleus via A(3) adenosine receptor.

AMID mediates adenosine-induced caspase-independent HuH-7 cell apoptosis

BACKGROUND/AIMS

The mechanism underlying extracellular adenosine-induced caspase-independent apoptosis in HuH-7 human hepatoma cells is not fully understood. The present study investigated the role for apoptosis-inducing factor (AIF)-homologous mitochondrion-associated inducer of death (AMID) in the pathway.

METHODS

To see the implication of AMID in adenosine-induced HuH-7 cell apoptosis, real-time reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescent cytochemistry, time-laps GFP monitoring, cell cycle analysis, flow cytometry, Western blotting, cell viability assay, and TUNEL staining were carried out.

RESULTS

Adenosine upregulated AMID expression in HuH-7 cells, and translocated AMID from the cytosol into the nucleus. Adenosine induced HuH-7 cell apoptosis, and the effect was further enhanced by overexpressing AMID. Adenosine-induced HuH-7 cell apoptosis, alternatively, was inhibited by knocking-down AMID.

CONCLUSION

The results of the present study provide evidence for AMID as a critical factor for adenosine-induced caspase-independent HuH-7 cell apoptosis.