On the Role of Adenosine A2A Receptor Gene Transcriptional Regulation in Parkinson's Disease

Epigenetic priming enhances antitumor immunity in platinum-resistant ovarian cancer

BackgroundImmune checkpoint inhibitors (ICIs) have modest activity in ovarian cancer (OC). To augment their activity, we used priming with the hypomethylating agent guadecitabine in a phase II study.MethodsEligible patients had platinum-resistant OC, normal organ function, measurable disease, and received up to 5 prior regimens. The treatment included guadecitabine (30 mg/m2) on days 1-4, and pembrolizumab (200 mg i.v.) on day 5, every 21 days. The primary endpoint was the response rate. Tumor biopsies, plasma, and PBMCs were obtained at baseline and after treatment.ResultsAmong 35 evaluable patients, 3 patients had partial responses (8.6%), and 8 (22.9%) patients had stable disease, resulting in a clinical benefit rate of 31.4% (95% CI: 16.9%-49.3%). The median duration of clinical benefit was 6.8 months. Long-interspersed element 1 (LINE1) was hypomethylated in post-treatment PBMCs, and methylomic and transcriptomic analyses showed activation of antitumor immunity in post-treatment biopsies. High-dimensional immune profiling of PBMCs showed a higher frequency of naive and/or central memory CD4+ T cells and of classical monocytes in patients with a durable clinical benefit or response (CBR). A higher baseline density of CD8+ T cells and CD20+ B cells and the presence of tertiary lymphoid structures in tumors were associated with a durable CBR.ConclusionEpigenetic priming using a hypomethylating agent with an ICI was feasible and resulted in a durable clinical benefit associated with immune responses in selected patients with recurrent OC.Trial registrationClinicalTrials.gov NCT02901899.FundingUS Army Medical Research and Material Command/Congressionally Directed Medical Research Programs (USAMRMC/CDMRP) grant W81XWH-17-0141; the Diana Princess of Wales Endowed Professorship and LCCTRAC funds from the Robert H. Lurie Comprehensive Cancer Center; Walter S. and Lucienne Driskill Immunotherapy Research funds; Astex Pharmaceuticals; Merck & Co.; National Cancer Institute (NCI), NIH grants CCSG P30 CA060553, CCSG P30 CA060553, and CA060553.

Adenosine A2A Receptors as Biomarkers of Brain Diseases

Extracellular adenosine is produced with increased metabolic activity or stress, acting as a paracrine signal of cellular effort. Adenosine receptors are most abundant in the brain, where adenosine acts through inhibitory A₁ receptors to decrease activity/noise and through facilitatory A_2A receptors (A_2AR) to promote plastic changes in physiological conditions. By bolstering glutamate excitotoxicity and neuroinflammation, A_2AR also contribute to synaptic and neuronal damage, as heralded by the neuroprotection afforded by the genetic or pharmacological blockade of A_2AR in animal models of ischemia, traumatic brain injury, convulsions/epilepsy, repeated stress or Alzheimer's or Parkinson's diseases. A_2AR overfunction is not only necessary for the expression of brain damage but is actually sufficient to trigger brain dysfunction in the absence of brain insults or other disease triggers. Furthermore, A_2AR overfunction seems to be an early event in the demise of brain diseases, which involves an increased formation of ATP-derived adenosine and an up-regulation of A_2AR. This prompts the novel hypothesis that the evaluation of A_2AR density in afflicted brain circuits may become an important biomarker of susceptibility and evolution of brain diseases once faithful PET ligands are optimized. Additional relevant biomarkers would be measuring the extracellular ATP and/or adenosine levels with selective dyes, to identify stressed regions in the brain. A_2AR display several polymorphisms in humans and preliminary studies have associated different A_2AR polymorphisms with altered morphofunctional brain endpoints associated with neuropsychiatric diseases. This further prompts the interest in exploiting A_2AR polymorphic analysis as an ancillary biomarker of susceptibility/evolution of brain diseases.

The exploration of Parkinson's disease: a multi-modal data analysis of resting functional magnetic resonance imaging and gene data

Parkinson's disease (PD) is the most universal chronic degenerative neurological dyskinesia and an important threat to elderly health. At present, the researches of PD are mainly based on single-modal data analysis, while the fusion research of multi-modal data may provide more meaningful information in the aspect of comprehending the pathogenesis of PD. In this paper, 104 samples having resting functional magnetic resonance imaging (rfMRI) and gene data are from Parkinson's Progression Markers Initiative (PPMI) and Alzheimer's Disease Neuroimaging Initiative (ADNI) database to predict pathological brain areas and risk genes related to PD. In the experiment, Pearson correlation analysis is adopted to conduct fusion analysis from the data of genes and brain areas as multi-modal sample characteristics, and the clustering evolution random forest (CERF) method is applied to detect the discriminative genes and brain areas. The experimental results indicate that compared with several existing advanced methods, the CERF method can further improve the diagnosis of PD and healthy control, and can achieve a significant effect. More importantly, we find that there are some interesting associations between brain areas and genes in PD patients. Based on these associations, we notice that PD-related brain areas include angular gyrus, thalamus, posterior cingulate gyrus and paracentral lobule, and risk genes mainly include C6orf10, HLA-DPB1 and HLA-DOA. These discoveries have a significant contribution to the early prevention and clinical treatments of PD.

Adenosine A2A Receptor Antagonists for Cancer Immunotherapy

Currently, the most promising therapeutic modality for cancer treatment is the blockade of immune checkpoint pathways, which has revolutionized cancer therapy in the past 15 years. Strategies targeting and modulating adenosine A_2A receptor (A_2AR), an emerging alternative immune checkpoint, have shown the potential to produce significant therapeutic effects. In this review, we describe the immunosuppressive activities of A_2AR and A_2BR in the tumor microenvironment (TME), followed by a summary and discussion of the structure-activity relationship (SAR) of the A_2AR (and dual A_2AR/A_2BR) antagonists that have been experimentally confirmed to exert oncoimmunological effects. This review also provides an update on the compounds under clinical evaluation and insights into the ligand binding modes of the receptor.

The protective effect of inosine against rotenone-induced Parkinson's disease in mice; role of oxido-nitrosative stress, ERK phosphorylation, and A2AR expression

Parkinson's disease (PD) is a severe disabling syndrome in which neuroinflammation and various signaling pathways are believed to mediate dopaminergic neurodegeneration. Here, the possible disease-modifying effects of the purine nucleoside inosine were examined against rotenone-induced PD. Mice were allocated into six groups, namely, a normal control group receiving dimethylsulfoxide, a PD control group receiving rotenone, a standard treatment group receiving L-dopa/carbidopa together with rotenone, and three treatment groups receiving inosine in low, medium, and high doses together with rotenone. At the end of the experimental protocol, three behavioral tests were performed to assess PD motor manifestations, namely, wire-hanging test, wood-walking test, and stair test. After performing the behavioral study, mice striata were isolated for the colorimetric assay of hypoxanthine, the enzyme-linked immunosorbent assay of dopamine, tumor necrosis factor-α, interleukin-6 and nitrite, the Western blot estimation of total and phosphorylated extracellular signal-regulated kinase (tERK and pERK), the polymerase chain reaction estimation of adenosine A_2A receptor (A2AR) expression, as well as the histopathological examination of substantia nigra and striatal tissue. Inosine protected against PD progression in a dose-dependent manner, with the effect comparable to the standard treatment L-dopa/carbidopa, evidenced by behavioral, biochemical, and histologic findings. The beneficial antiparkinsonian effect of inosine could be attributed to the ability of the drug to ameliorate neuroinflammation and oxido-nitrosative stress, together with suppression of ERK phosphorylation and down-regulation of A2AR expression. Inosine could therefore be considered as a disease-modifying agent against PD, but further studies are claimed to confirm such effects clinically.