Adenosine is a metabolite produced abundantly in the tumor microenvironment, dampening immune response in inflamed tissues via adenosine A2A receptor (A2AR) which is widely expressed on immune cells, inhibiting anti-tumor immune response accordingly. Therefore, blocking adenosine signaling pathway is of potential to promote anti-tumor immunity. This review briefly introduces adenosine signaling pathway, describes its role in regulating tumor immunity and highlights A2AR blockade in cancer therapy. Prospective anti-tumor activity of adenosine/A2AR inhibition has been revealed by preclinical data, and a number of clinical trials of A2AR antagonists are under way. Primary results from clinical trials suggest that A2AR antagonists are well tolerated in cancer patients and are effective both as monotherapy and in combination with other therapies. In the future, finding predictive biomarkers are critical to identify patients most likely to benefit from adenosine pathway blockade, and further researches are needed to rationally combine A2AR antagonists with other anti-tumor therapies.
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Adenosine/therapeutic use* ; Adenosine A2 Receptor Antagonists/therapeutic use* ; Humans ; Lung Neoplasms ; Receptor, Adenosine A2A/metabolism* ; Tumor Microenvironment

OBJECTIVETo establish a mice model with selective inactivation adenosine A2A receptors (A2ARs) in peripheral white blood cells (PWBC).

METHODSA2ARs were selectively inactivated in PWBCs by transplanting bone marrow cells (BMCs) from A2AR knockout (KO) mice into their wild type (WT) littermates after a single total body irradiation of 9.5 Gy or fractionated total body irradiation of 6.2 Gy x 2. The efficiency of reconstitution of bone marrow-derived cells in chimeric mice was assessed.

RESULTSPCR band patterns changed from the recipient pattern (one band of 330 bp) to the donor (two bands of 300 and 330 bp) pattern. Immunohistochemistry analysis showed that 10.21% of cells were A2AR+ in PWBCs in KO--> WT mice, whereas 96.72% of cells were A2AR+ in WT mice. The survival rates of mice irradiated with 6.2 Gy x 2 and transplanted with more than 6 x 10(6) BMCs were about 91%.

CONCLUSIONA murine model of selective inactivation adenosine A2A receptors in PWBCs was established successfully.

Animals ; Gene Deletion ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Models, Animal ; Receptor, Adenosine A2A ; genetics

Luteolin, a widespread flavonoid, has been known to have neuroprotective activity against various neurologic diseases such as epilepsy, and Alzheimer’s disease. However, little information is available regarding the hypnotic effect of luteolin. In this study, we evaluated the hypnotic effect of luteolin and its underlying mechanism. In pentobarbital-induced sleeping mice model, luteolin (1, and 3 mg/kg, p.o.) decreased sleep latency and increased the total sleep time. Through electroencephalogram (EEG) and electromyogram (EMG) recording, we demonstrated that luteolin increased non-rapid eye movement (NREM) sleep time and decreased wake time. To evaluate the underlying mechanism, we examined the effects of various pharmacological antagonists on the hypnotic effect of luteolin. The hypnotic effect of 3 mg/kg of luteolin was not affected by flumazenil, a GABAA receptor-benzodiazepine (GABAAR-BDZ) binding site antagonist, and bicuculine, a GABAAR-GABA binding site antagonist. On the other hand, the hypnotic effect of 3 mg/kg of luteolin was almost completely blocked by caffeine, an antagonist for both adenosine A1 and A2A receptor (A1R and A2AR), 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), an A1R antagonist, and SCH-58261, an A2AR antagonist. From the binding affinity assay, we have found that luteolin significantly binds to not only A1R but also A2AR with IC₅₀ of 1.19, 0.84 μg/kg, respectively. However, luteolin did not bind to either BDZ-receptor or GABAAR. From these results, it has been suggested that luteolin has hypnotic efficacy through A1R and A2AR binding.
Adenosine ; Animals ; Binding Sites ; Caffeine ; Electroencephalography ; Epilepsy ; Eye Movements ; Flumazenil ; Hand ; Hypnotics and Sedatives ; Luteolin ; Mice ; Receptor, Adenosine A1 ; Receptor, Adenosine A2A ; Sleep Initiation and Maintenance Disorders

OBJECTIVETo discuss the mechanism of scar hypertrophy in adenosine receptor A(2A) (A(2A) R) knockout mice.

METHODSAnimal models of hypertrophic scar were established in 12 A(2A) R knockout mice and 12 wild-type mice as control. The thickness and the size of transverse section of the hypertrophic scar were observed by H-E staining. The hydroxyproline (HYP) in the scar was measured colorimetrically. The TGF-beta expression was tested by Western blotting method.

RESULTSThe hypertrophic scar in wild-type mice was more severe than that in knockout mice. Compared with self-control, the increase of the thickness and the size of transverse section of hypertrophic scar was markedly higher in wild-type group than in the knockout group (P < 0.01). There was significant difference in HYP content between the two groups (P < 0.01). Compared with self-control, the increase of TGF-beta expression in wild-type group was much more than that in knockout group (P < 0.01).

CONCLUSIONSThe TGF-beta expression decreases in the A(2A) R knockout mice. The scar hypertrophy is also much less in the A(2A) R knockout mice.

Animals ; Cicatrix ; metabolism ; pathology ; Disease Models, Animal ; Mice ; Mice, Knockout ; Receptor, Adenosine A2A ; genetics ; Transforming Growth Factor beta ; genetics ; metabolism

PURPOSE: Polydeoxyribonucleotide (PDRN), consisting of a mixture of deoxyribonucleotide polymers, has been suggested to have anti-inflammatory effects and enhance angiogenesis as an adenosine A(2A) receptor agonist. The aim of this study was to report the effectiveness of PDRN as an adjuvant therapy after surgical debridement in MRONJ (medication-related osteonecrosis of the jaw) patients. MATERIALS AND METHODS: Five patients (1 male, 4 females, age 65~79 years) who were diagnosed with MRONJ stage 2 or 3 underwent surgical debridement and PDRN mucosal injection. After surgical debridement, patients were subject to daily injection with 1 ml of PDRN around the surgical wound for 14 days. RESULT: The patients' symptoms gradually disappeared. The surgical wound uneventfully healed, and no recurrence was observed during the follow-up period. CONCLUSION: Although further studies are required, the present study first describes the possibility of PDRN as a useful option for MRONJ treatment.
Debridement ; Female ; Follow-Up Studies ; Humans ; Jaw ; Male ; Observational Study ; Osteonecrosis ; Polymers ; Receptor, Adenosine A2A ; Recurrence ; Wounds and Injuries

Adult rats were implanted with sleep-wake recording electrodes in our experiments. Polygraphic signs of undisturbed sleep-wake activities were recorded for 24 h before cocaine administration, cocaine withdrawal day 1 (acute), day 8 (subacute), and day 14 (subchronic). Western blot method was performed to examine the expression levels of adenosine receptor subtypes in hypothalamus and cerebellum. Non rapid eye movement (NREM) sleep was significantly increased during nighttime (P < 0.01) and daytime (P < 0.05) on withdrawal day 8. The increase of NREM sleep was significant during nighttime (P < 0.01) and slight during daytime on withdrawal day 14, whereas both daytime and nighttime rapid eye movement (REM) sleeps were reduced markedly (P < 0.01) on withdrawal day 8 and 14. In addition, A2A receptor level was significantly enhanced on cocaine withdrawal day 8 and day 14 (P < 0.05), whereas A1 receptor level reduced markedly on withdrawal day 14 (P < 0.05). However, compared with that in the control group, no significant changes existed among adenosine A1, A2A and A2B receptors in rat cerebellum on cocaine withdrawal day 1, day 8 and day 14. Our findings suggest that sleep disorder caused by subacute and subchronic cocaine abstinence may be associated with over-expression of adenosine A2A receptor in rat hypothalamus to some extent.
Animals ; Cocaine ; adverse effects ; Dyssomnias ; chemically induced ; Electroencephalography ; Hypothalamus ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, Adenosine A2A ; metabolism ; Substance Withdrawal Syndrome

OBJECTIVETo investigate the effect of adenosine A2A receptor knockout (A(2A)RKO) on relationship between continuous activation of phospho-c-Jun N-terminal kinase (P-JNK) and expression of nerve cell apoptosis in hippocampus CA1 domain of newborn mice after hypoxia/ischemia brain damage(HIBD) and its potential mechanism.

METHODSA(2A)RKO mice and adenosine A2A receptor wildtype (A(2A)RWT) littermates (n = 80) were divided into Sham operation group (S) and model group (M), 1, 3 and 7 day after HIBD, totally 8 groups. HIBD was developed with 7 day-old neonatal mice according classical Rice-Vannucci method. It was tested the effect of A(2A)RKO on short-term neurofunctional outcomes consisted of three developmental reflexes (righting, geotaxis and cliff aversion), the changes of brain pathology with hematoxylin-eosin (HE) staining and Nissl staining, the expressions of nerve cell apoptosis with terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling(TUNEL) staining and P-JNK were observed by immunohistochemistry.

RESULTSThe neurological behavior injuries and brain histopathological damages and nerve apoptosis cells were aggravated in A(2A)RKO newborn mice after HIBD. The positive expressions of P-JNK were significantly higher in the ischemic hippocampus CA1 domain after HIBD than ones in group S respectively (P < 0.01), reaching to peak at 1 day and then began gradually decreasing. P-JNK expression in model knockout(MKO) at 1, 3 and 7 day increased greatly compared to those in the previous time point of corresponding model wildtype (MWT) (P < 0.01, P < 0.05, P > 0.05); there was a positive correlation between the expressions of P-JNK and nerve cell apoptosis after HIBD in newborn mice(r = 0.837, P < 0.01).

CONCLUSIONEarly continuous activation of P-JNK might be involved in the aggravated nerve apoptosis cells and brain damage induced by A(2A) RKO newborn mice after HIBD.

Animals ; Animals, Newborn ; Apoptosis ; Hypoxia-Ischemia, Brain ; metabolism ; pathology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Mice ; Mice, Knockout ; Neurons ; drug effects ; metabolism ; pathology ; Receptor, Adenosine A2A ; genetics

OBJECTIVETo study the effects of caffeine citrate on myelin basic protein (MBP) expression in the cerebral white matter of neonatal rats with hypoxic-ischemic brain damage (HIBD) and the related mechanism.

METHODSForty-eight seven-day-old Sprague-Dawley neonatal rats were randomly assigned to 3 groups: sham operation (n=16), HIBD (n=16) and HIBD+caffeine citrate (n=16). The rats in the HIBD and HIBD+caffeine citrate groups were subjected to left common carotid artery ligation, and then were exposed to 80 mL/L oxygen and 920 mL/L nitrogen for 2 hours to induce HIBD. The rats in the sham operation group were only subjected to a sham operation, without the left common carotid artery ligation or hypoxia exposure. Caffeine citrate (20 mg/kg) was injected intraperitoneally before hypoxia ischemia (HI) and immediately, 24 hours, 48 hours and 72 hours after HI. The other two groups were injected intraperitoneally with an equal volume of normal saline at the corresponding time points. On postnatal day 12, the expression of MBP in the left subcortical white matter was detected by immunohistochemistry, and the levels of adenosine A1 receptor mRNA and A2a receptor mRNA in the left brain were detected by real-time PCR.

RESULTSThe expression of MBP in the left subcortical white matter in the HIBD group was lower than in the sham operation group (P<0.05). The MBP expression in the HIBD+caffeine citrate group was significantly higher than in the HIBD group, but was still lower than the sham operation group (P<0.05). Real-time PCR showed that the adenosine A1 receptor mRNA expression was significantly higher in the HIBD group than in the sham operation group, and it was significantly lower in the HIBD+caffeine citrate group than in the HIBD group (P<0.05).

CONCLUSIONSCaffeine citrate can improve brain white matter damage following HIBD in neonatal rats and the protection mechanism might be related with the down-regulation of adenosine A1 receptor expression.

Animals ; Animals, Newborn ; Caffeine ; pharmacology ; Citrates ; pharmacology ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Male ; Myelin Basic Protein ; analysis ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptor, Adenosine A1 ; genetics ; Receptor, Adenosine A2A ; genetics ; White Matter ; chemistry

Recently, activation of the adenosine A2A receptors has been shown to exert protection against peripheral tissue injuries but aggravation in the central nervous system (CNS) injuries. To explore the different effects of adenosine A2A receptors and try to perform some new treatment strategies for peripheral tissue and CNS traumas, we constructed the mouse models of skin trauma, skin combined radiation-impaired wound and traumatic brain injury (TBI), respectively. Wild type mice and A2A receptor gene knockout mice were both used in the experiments. In skin trauma and combined radiation-impaired wound models, the time of wound healing was observed, while in TBI model, neurological deficit scores, water content in injured brain and glutamate concentration in cerebral spinal fluid (CSF) were detected at 24 h after TBI. The results showed that in skin trauma and combined radiation-impaired wound models, CGS21680 (an agonist of the A2A receptors) promoted while A2A receptor gene knockout delayed the course of skin wound healing. On the contrary, in TBI model, A2A receptor gene knockout, not CGS21680, showed a protective role by inhibition of glutamate release. These data further indicate that promoting glutamate release may account for the different effects of A2A receptor activation in CNS injury and peripheral tissue injury models. These findings may provide some experimental evidence and a new strategy for clinical treatment of peripheral tissue damages by agonists of A2A receptors, while treatment of CNS injuries by antagonists of A2A receptors.
Adenosine ; analogs & derivatives ; pharmacology ; Animals ; Brain ; pathology ; Brain Injuries ; physiopathology ; Disease Models, Animal ; Glutamic Acid ; cerebrospinal fluid ; Mice ; Mice, Knockout ; Phenethylamines ; pharmacology ; Receptor, Adenosine A2A ; genetics ; physiology ; Wound Healing

OBJECTIVE: To elucidate the action mechanism of Xingnaojing Injection (, XNJI) for sepsis, and to target screen the potential bioactive ingredients. METHODS: An integrated protocol that combines in silico target screen (molecular docking) and database mapping was employed to find the potential inhibitors from XNJI for the sepsis-related targets and to establish the compound-target (C-T) interaction network. The XNJI's bioactive components database was investigated and the sepsis-associated targets were comprehensively constructed; the 3D structure of adenosine receptor A2a and 5-lipoxygenase proteins were established and evaluated with homology modeling method; system network pharmacology for sepsis treatment was studied between the bioactive ingredients and the sepsis targets using computational biology methods to distinguish inhibitors from non inhibitors for the selected sepsis-related targets and C-T network construction. RESULTS: Multiple bioactive compounds in the XNJI were found to interact with multiple sepsis targets. The 32 bioactive ingredients were generated from XNJI in pharmacological system, and 21 potential targets were predicted to the sepsis disease; the biological activities for some potential inhibitors had been experimentally confirmed, highlighting the reliability of in silico target screen. Further integrated C-T network showed that these bioactive components together probably display synergistic action for sepsis treatment. CONCLUSIONS The uncovered mechanism may offer a superior insight for understanding the theory of the Chinese herbal medicine for combating sepsis. Moreover, the potential inhibitors for the sepsis-related targets may provide a good source to find new lead compounds against sepsis disease.
Arachidonate 5-Lipoxygenase ; metabolism ; Computer Simulation ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; therapeutic use ; Humans ; Injections ; Phytochemicals ; therapeutic use ; Receptor, Adenosine A2A ; metabolism ; Reproducibility of Results ; Sepsis ; drug therapy ; metabolism