DRD2 Expression Research Articles

Liposomal Form of L-Dopa and SH-Sy5y Cell-Derived Exosomes Modulate the Tyrosine Hydroxylase/Dopamine Receptor D2 Signaling Pathway in Parkinson's Rat Models.

Parkinson's disease is a progressive neurodegenerative disorder in which dopaminergic neurons located in the substantia nigra are gradually lost. Currently, combined treatment strategies are receiving increasing attention as potential therapeutic approaches for Parkinson's disease. This study aimed to evaluate the potential effects of exosomes released from SH-Sy5y cells and the liposomal form of L-dopa on Parkinson's rat models.Twenty-five male Wistar albino rats, in five groups, were included in this study. Parkinson's disease was induced through microinjection of 6-OHDA (2.5mg/mL) into the right substantia nigra. The exosomes released from the SH-Sy5y cell line were isolated and administered (0.2µg/5 µL) alone or in combination with the liposomal form of L-Dopa (80mg/kg) to the defined model groups. Behavioral tests and molecular assays were conducted to evaluate the expression levels of tyrosine hydroxylase (TH) and dopamine receptor D2 (DRD2).The rats in the groups receiving the combined liposomal form of L-Dopa and exosome treatment and the liposomal form of L-Dopa alone showed a significant improvement in their movement ability (p < 0.05). At molecular levels, these two groups also exhibited significant increases in Th (0.005 ± 0.001) and Drd2 (0.002 ± 0.0001) expression compared to controls (p < 0.05). The observed alterations of Th and Drd2 expression were not statistically significant in exosome- and L-Dopa-treated groups.The current study shows that exosome-derived neuronal cells and liposomal form of L-Dopa can protect different cells against pathological complications such as Parkinson's disease.

Phase 2 study of DRD2 antagonist/ClpP agonist ONC201 in neuroendocrine tumors.

3002 Background: ONC201, an imipridone with specificity for the dopamine-like DRD2 receptor and the mitochondrial protease ClpP, imparts anti-cancer effects via up-regulation of TRAIL/DR5, dual AKT/ERK pathway inhibition, and promotion of an integrated stress response. Select neuroendocrine tumors are known to secrete dopamine and harbor elevated DRD2 expression, which is most pronounced in pheochromocytoma-paraganglioma (PC-PG). Methods: This investigator-initiated single center trial (NCT03034200) enrolled 10 patients with metastatic PC-PG to cohort A and 12 patients with other neuroendocrine tumors to cohort B. The primary endpoint was response using MRI or CT, PET-CT and/or PET-MRI imaging defined as CR + PR + SD &gt; 3 months by RECIST criteria assessed by investigator. Secondary endpoints included progression-free survival, overall survival and safety. ONC201 was administered at 625 mg by oral capsules once each week. CT scans and tumor markers (plasma chromogranin and metanephrines) were followed at 6 weeks, 3 months and then every 3 months. Patients with clinical benefit could receive stereotactic body radiotherapy (SBRT) for non-indicator (e.g. bone) metastases. The data cutoff for this analysis is December 1, 2020. Results: In Arm A (n = 10; all paraganglioma) 5 patients exhibited a PR and 2 additional patients exhibited SD &gt; 3 months. Median duration of therapy for patients was 9 months (range: 1.5-33) with 5 patients &gt; 1 year. In Arm B (n = 12) there were 1 PR and 2 SD &gt; 3 months. Median duration of therapy was 3 months (range: 1-33). The partial response occurred in a patient with desmoplastic small round cell tumor who remains on treatment for &gt; 2 years. There was no instance of dose modification or discontinuation due to treatment-related adverse events. Conclusions: ONC201 is well tolerated at 625mg weekly in adults with advanced neuroendocrine tumors and is associated with clinical benefit that includes tumor response, particularly in paraganglioma patients. A more intense schedule of 2 daily doses each week is under evaluation, in addition to other neuroendocrine tumors. Clinical trial information: NCT03034200.

Dopamine D1 receptor alleviates doxorubicin-induced cardiac injury by inhibiting NLRP3 inflammasome

Doxorubicin (DOX) is a broad-spectrum antineoplastic drug; however, its serious cardiotoxic side effects in inflammatory responses limit its use in clinical applications. Dopamine D1 receptor (DRD1), a G protein-coupled receptor, is crucial for the development and function of the nervous system; additionally, it also play a role in immune regulation. However, the specific role of DRD1 in DOX-induced cardiac inflammation has not yet been clarified. Here, we discovered that DRD1 expression was induced by DOX treatment in H9C2 cardiomyocytes. DRD1 activation by A-68930, a DRD1-specific agonist, decreased DOX-induced nucleotide-binding domain-like receptor protein 3 (NLRP3) expression, caspase-1 activation, and IL-1β maturation in H9C2 cells. Expression of the cytokines IL-1β and IL-18 in the supernatants was also inhibited by A-68930 treatment. DRD1 knockdown, using siRNA, abolished the effects of A-68930 on the DOX-induced NLRP3 inflammasome. Furthermore, we found that DRD1 signaling downregulated the NLRP3 inflammasome in H9C2 cells through cyclic adenosine monophosphate (cAMP). Moreover, application of A-68930 to activate DRD1 reduced cardiac injury and fibrosis in a DOX-treated mouse model by suppressing the NLRP3 inflammasome in the heart. These findings indicate that DRD1 signaling may protect against DOX-induced cardiac injury by inhibiting the NLRP3 inflammasome-mediated inflammation.

Dopamine D2 receptor agonist, bromocriptine, remodels adipose tissue dopaminergic signalling and upregulates catabolic pathways, improving metabolic profile in type 2 diabetes

Background and objectivesThe therapeutic effects of the dopamine D2 receptor (D2R) agonist, bromocriptine, in type 2 diabetes (T2D) have been attributed to central nervous system actions. However, peripheral dopamine directly modulates glucose uptake in insulin-sensitive tissues and lipid metabolism in adipose tissue (AT). We hypothesized that the dopaminergic system may be impaired in the adipose tissue of patients with T2D and that the therapeutic actions of bromocriptine could involve the modulation of metabolism in this tissue. MethodsThe expression of dopamine receptors was evaluated in visceral AT samples from patients with obesity and stratified in several groups: insulin sensitive (IS); insulin resistance (IR) normoglycaemic; insulin resistant prediabetic; insulin resistant diabetic, according to Ox-HOMA2IR, fasting glycaemia and HbA1c levels. T2D Goto-Kakizaki rats (GK) were fed a high-caloric diet (HCD) for five months and treated with bromocriptine (10 mg/kg/day, i.p.) in the last month. The levels of dopaminergic system mediators and markers of insulin sensitivity and glucose and lipid metabolism were assessed in the peri-epididymal adipose tissue (pEWAT) and brown (BAT) adipose tissues, liver, and skeletal muscle. ResultsPatients with IR presented a decreasing trend of DRD1 expression in the visceral adipose tissue, being correlated with the expression of UCP1, PPARA, and insulin receptor (INSR) independently of insulin resistance and body mass index. Although no differences were observed in DRD2, DRD4 expression was significantly decreased in patients with prediabetes and T2D. In HCD-fed diabetic rats, bromocriptine increased D1R and tyrosine hydroxylase (TH) levels in pEWAT and the liver. Besides reducing adiposity, bromocriptine restored GLUT4 and PPARγ levels in pEWAT, as well as postprandial InsR activation and postabsorptive activation of lipid oxidation pathways. A reduction of liver fat, GLUT2 levels and postprandial InsR and AMPK activation in the liver was observed. Increased insulin sensitivity and GLUT4 levels in BAT and an improvement of the overall metabolic status were observed. ConclusionsBromocriptine treatment remodels adipose tissue and the liver dopaminergic system, with increased D1R and TH levels, resulting in higher insulin sensitivity and catabolic function. Such effects may be involved in bromocriptine therapeutic effects, given the impaired expression of dopamine receptors in the visceral adipose tissue of IR patients, as well as the correlation of D1R expression with InsR and metabolic mediators.

A Pilot Study Investigating the Role of Gender in the Intergenerational Relationships between Gene Expression, Chronic Pain, and Adverse Childhood Experiences in a Clinical Sample of Youth with Chronic Pain.

Chronic pain is a highly prevalent and costly issue that often emerges during childhood or adolescence and persists into adulthood. Adverse childhood experiences (ACEs) increase risk for several adverse health conditions, including chronic pain. Recent evidence suggests that parental trauma (ACEs, post-traumatic stress disorder (PTSD) symptoms) confers risk of poor health outcomes in their children. Intergenerational relationships between parental trauma and child chronic pain may be mediated by epigenetic mechanisms. A clinical sample of youth with chronic pain and their parents completed psychometrically sound questionnaires assessing ACEs, PTSD symptoms, and chronic pain, and provided a saliva sample. These were used to investigate the intergenerational relationships between four epigenetic biomarkers (COMT, DRD2, GR, and SERT), trauma, and chronic pain. The results indicated that the significant biomarkers were dependent upon the gender of the child, wherein parental ACEs significantly correlated with changes in DRD2 expression in female children and altered COMT expression in the parents of male children. Additionally, the nature of the ACE (maltreatment vs. household dysfunction) was associated with the specific epigenetic changes. There may be different pathways through which parental ACEs confer risk for poor outcomes for males and females, highlighting the importance of child gender in future investigations.

D4 and D5 dopamine receptor mRNA expression in human peripheral blood lymphocytes among cooccurring opioid and amphetamine-type stimulants use disorder undergoing methadone maintenance therapy

Introduction: Opioid and amphetamine type stimulant (ATS) exert their rewarding effects by stimulating the dopaminergic system in the mesolimbic area. It has been suggested that dopamine system in peripheral blood lymphocytes reflect the central dopamine system’s activity and pathology, especially in neuropsychiatric diseases including drug addiction. The present study aimed to assess the effect of co-occurring opioid and ATS (COATS) addiction towards mRNA expression of dopamine receptors DRD4 and DRD5 in peripheral blood lymphocytes (PBLs) of drug dependent subjects (n=36) undergoing methadone maintenance therapy in comparison to control subjects (n=36).&#x0D; Materials and methods: Ten mL blood were obtained from the subjects followed by lymphocyte isolation, RNA extraction and reverse transcription. DRD4 and DRD5 mRNA expression in peripheral lymphocytes was assessed using real-time PCR. The DRD4 mRNA expression but not DRD5 was significantly reduced in the peripheral lymphocytes of COATS subjects.&#x0D; Results: Mean expression value for DRD4 was 14.0+0.24 among patients and 13.3+0.25 among control subjects. For DRD5 it was 12.87 + 0.75 among patients and 12.59 + 1.24 among controls.&#x0D; Conclusion: Inconclusion, co-occurring opioid and ATS addiction was associated with persistent deficiency of DRD4 but not DRD5 in PBLs.&#x0D; Bangladesh Journal of Medical Science Vol.20(3) 2021 p.563-568

Total barley maiya alkaloids inhibit prolactin secretion by acting on dopamine D2 receptor and protein kinase A targets

Ethnopharmacological relevance: Barley maiya from gramineous plants (Hordeum vulgare L.) is obtained from ripe fruits through germination and drying. It is often used to treat diseases associated with high prolactin levels. Objective: To investigate the anti-hyperprolactinemia (anti-HPRL) mechanisms of total barley maiya alkaloids (TBMA) and hordenine. Methods: This experiment included 9 groups: Normal group, TBMA group, hordenine group, TBMA + haloperidol group, TBMA + forskolin group, TBMA + 8-bromo-cAMP group, hordenine + haloperidol group, hordenine + forskolin group, and hordenine + 8-bromo-cAMP group. The prolactin (PRL) concentration in the supernatant and the total cAMP concentration in the cells were detected by ELISA. The expression levels of PRL, dopamine D2 receptor (DRD2) and cAMP/PKA/CREB protein were measured by Western Blot. Results: In the TBMA group and the hordenine group, the PRL level in MMQ cells was significantly decreased, but in GH3 cells there was no change. DRD2 expression level was markedly increased, cAMP concentration was decreased, and the activity of PKA and CREB declined in MMQ cells. Compared with the TBMA group, there was a significant decrease of DRD2 expression level, a remarkable increase of PRL secretion and an increase of cAMP/PKA/CREB expression in MMQ cells within the TBMA + haloperidol group. Compared with the forskolin group, there was no significant change in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the TBMA + forskolin group. There was a decrease in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the TBMA + 8-bromo-cAMP group compared with the 8-bromo-cAMP group. Compared with the hordenine group, DRD2 expression level was significantly decreased, PRL secretion was markedly increased, and cAMP/PKA/CREB expression level was increased in MMQ cells within the hordenine + haloperidol group. There was no significant change in PRL secretion and cAMP/PKA/CREB expression level in MMQ cells within the hordenine + forskolin group compared with the forskolin group and within the hordenine + 8-bromo-cAMP group compared with the 8-bromo-cAMP group. Conclusion: TBMA and hordenine can both play an anti-HPRL role via DRD2, and TBMA can also act on PKA targets to exert its anti-HPRL effect. TBMA and hordenine may be potential treatment strategies for HPRL.

Fetal methylphenidate exposure induced ADHD-like phenotypes and decreased Drd2 and Slc6a3 expression levels in mouse offspring

Methylphenidate (MPD) is used as a first-line treatment for attention-deficit/hyperactivity disorder (ADHD). The number of prescriptions for ADHD patients is increasing, suggesting that the number of fertile women using such medication might be also increasing. The purpose of this study was to clarify the effects of MPD exposure during the fetal period on infant development, behavior, learning, and memory in mice. Expression levels of candidate genes associated with ADHD were also determined in the brain of pups born to MDP-treated dams who were administered MPD orally at a dose of 2.5, 7.5, or 15 mg/kg daily from gestational day 1 to the day before delivery. Offspring aged 6–8 weeks were subjected to the spontaneous locomotor activity, elevated plus-maze, and passive avoidance tests and therapeutic treatments with MPD or atomoxetine. Fetal MPD exposure induced ADHD-like phenotypes, such as hyperactivity and impulsivity, in mouse offspring, which were suppressed by treatment with MPD and atomoxetine. These mice showed decreased Drd2 and Slc6a3 expression levels in the brain, which are often observed in ADHD model animals. Our results suggest that continuous use of MPD during pregnancy induces ADHD phenotypes in the offspring.

Tumor suppressor DRD2 facilitates M1 macrophages and restricts NF-κB signaling to trigger pyroptosis in breast cancer.

Rationale: Breast cancer (BrCa) is the most common cancer worldwide, and the 5-year relative survival rate has declined in patients diagnosed at stage IV. Advanced BrCa is considered as incurable, which still lack effective treatment strategies. Identifying and characterizing new tumor suppression genes is important to establish effective prognostic biomarkers or therapeutic targets for late-stage BrCa.Methods: RNA-seq was applied in BrCa tissues and normal breast tissues. Through analyzing differentially expressed genes, DRD2 was selected for further analysis. And expression and promoter methylation status of DRD2 were also determined. DRD2 functions were analyzed by various cell biology assays in vitro. Subcutaneous tumor model was used to explore DRD2 effects in vivo. A co-cultivated system was constructed to investigate interactions of DRD2 and macrophages in vitro. WB, IHC, IF, TUNEL, qRT-PCR, Co-IP, Antibody Array, and Mass Spectrum analysis were further applied to determine the detailed mechanism.Results: In BrCa, DRD2 was found to be downregulated due to promoter methylation. Higher expression of DRD2 positively correlated with longer survival times especially in HER2-positive patients. DRD2 also promoted BrCa cells sensitivity to Paclitaxel. Ectopic expression of DRD2 significantly inhibited BrCa tumorigenesis. DRD2 also induced apoptosis as well as necroptosis in vitro and in vivo. DRD2 restricted NF-κB signaling pathway activation through interacting with β-arrestin2, DDX5 and eEF1A2. Interestingly, DRD2 also regulated microenvironment as it facilitated M1 polarization of macrophages, and triggered GSDME-executed pyroptosis.Conclusion: Collectively, this study novelly manifests the role of DRD2 in suppressing BrCa tumorigenesis, predicting prognosis and treatment response. And this study further reveals the critical role of DRD2 in educating M1 macrophages, restricting NF-κB signaling pathway and triggering different processes of programmed cell death in BrCa. Taking together, those findings represent a predictive and therapeutic target for BrCa.

Aspergillus versicolor Inhalation Triggers Neuroimmune, Glial, and Neuropeptide Transcriptional Changes.

Increasing evidence associates indoor fungal exposure with deleterious central nervous system (CNS) health, such as cognitive and emotional deficits in children and adults, but the specific mechanisms by which it might impact the brain are poorly understood. Mice were exposed to filtered air, heat-inactivated Aspergillus versicolor (3 × 105 spores), or viable A. versicolor (3 × 105 spores) via nose-only inhalation exposure 2 times per week for 1, 2, or 4 weeks. Analysis of cortex, midbrain, olfactory bulb, and cerebellum tissue from mice exposed to viable A. versicolor spores for 1, 2, and 4 weeks revealed significantly elevated pro-inflammatory (Tnf and Il1b) and glial activity (Gdnf and Cxc3r1) gene expression in several brain regions when compared to filtered air control, with the most consistent and pronounced neuroimmune response 48H following the 4-week exposure in the midbrain and frontal lobe. Bulk RNA-seq analysis of the midbrain tissue confirmed that 4 weeks of A. versicolor exposure resulted in significant transcriptional enrichment of several biological pathways compared to the filtered air control, including neuroinflammation, glial cell activation, and regulation of postsynaptic organization. Upregulation of Drd1, Penk, and Pdyn mRNA expression was confirmed in the 4-week A. versicolor exposed midbrain tissue, highlighting that gene expression important for neurotransmission was affected by repeated A. versicolor inhalation exposure. Taken together, these findings indicate that the brain can detect and respond to A. versicolor inhalation exposure with changes in neuroimmune and neurotransmission gene expression, providing much needed insight into how inhaled fungal exposures can affect CNS responses and regulate neuroimmune homeostasis.

Изменение экспрессии генов дофаминовых рецепторов в крови крыс под воздействием хронического стресса

Stress response is a multifactorial condition which is formed under extreme environmental exposure due to various neuroendocrine systems interactions. Dopaminergic system plays a key role in stress response through the dopamine which effect is realized after binding with special dopamine receptors types D1-D5. Expression of these receptors varies in different tissues, organs and specific brain structures but there is a special interest in their genes expression level in peripheral blood that can be served as additional marker to evaluate the chronic stress degree. Herein we determine the influence of various types induced chronic stress exposure during 6 months (such as exhausting physical activity (forced swimming), immobilization stress, and their combinations (swimming with immobilization)) on Drd1, Drd2 and Drd3 genes expression level in Wistar rats’ peripheral blood. According to our results, no activity for Drd2 and Drd3 genes is shown; however significant overexpression of Drd1 gene was detected in all studied groups after 3 months exposure compared to the data before experiment beginning, whereas after 6 months the relative expression level significantly decreased in the group with immobilization stress, which proves the negative effect of this type of chronic stress on the production of dopamine receptors of the D1 type. Thus, Drd1 gene activity in the blood can serve as a marker for assessing the severity of chronic stress in rats.

HGG-18. CLINICAL EFFICACY OF ONC201 IN THALAMIC H3 K27M-MUTANT GLIOMA

ONC201, a bitopic DRD2 antagonist and allosteric ClpP agonist, has shown encouraging efficacy in H3 K27M-mutant glioma. Given that the thalamus has the highest extra-striatal expression of DRD2, we performed an integrated preclinical and clinical analysis of ONC201 in thalamic H3 K27M-mutant glioma. ONC201 was effective in mouse intra-uterine electroporation (IUE)-generated H3 K27M-mutant gliomas, with an in vitro IC50 of 500 nM and 50% prolongation of median survival in vivo (p=0.02, n=14). We analyzed thalamic H3 K27M-mutant glioma patients treated with ONC201 on active clinical trials as of 5/22/19 enrollment (n=19 recurrent and 10 post-radiation, non-recurrent; 5–70 years old). As of 12/18/2019, PFS6 and OS12 are 26.3% and 36.8%, respectively, in the recurrent group. For non-recurrent patients, with median follow up of 21.9 months (8.6–26.6) from diagnosis, median PFS or OS have not been reached. This surpasses historical OS of 13.5 months. Best response by RANO includes 1 CR, 3 PR, 4 SD, 8 PD for recurrent patients and 2 PR, 4 SD, 1 PD for non-recurrent patients (4 on-trial patients experienced regressions that are yet unconfirmed responses). Median duration of response for recurrent patients is 14.0 months (2.0–33.1). Furthermore, H3 K27M cell-free tumor DNA in plasma and CSF correlated with MRI response. In summary, single agent ONC201 administered at recurrence, or adjuvantly following radiation, demonstrates promising clinical efficacy in thalamic H3 K27M-mutant glioma patients who currently have no effective treatments following radiation. Investigations are ongoing to assess whether micro-environmental DRD2 expression explains the early exceptional responses in thalamic H3 K27M-mutant glioma.

MODL-06. PRECLINICAL EFFICACY OF THE IMIPRIDONE ONC-206 AGAINST MEDULLOBLASTOMA

Treatment for medulloblastoma (MB) is typically ineffective for MYC amplified or metastatic SHH, Group 3 and 4 subgroups. Promising preclinical and clinical results have been obtained in brain cancers treated with ONC-201, a selective antagonist of DRD2, a G-protein coupled receptor that regulates prosurvival pathways. Herein, we report the activity of ONC-201 and ONC-206, which has increased non-competitive antagonism of DRD2, against MB. We treated three different MB cell types representative of SHH- and Group 3-like cells, with varied levels of DRD2 expression, and consistently observed increased cell death in a dose-dependent manner at lower doses of ONC-206 compared to ONC-201. We also evaluated ClpP as an additional drug target in MB. ClpP is a mitochondrial protease that has been shown to directly bind and be activated by ONC 201, and is highly expressed at the protein level across pediatric MB, malignant glioma and ATRT, but not normal brain. We observed that similar to ONC-201, ONC-206 treatment of MB cells induces the restoration of mitochondrial membrane potential to the non-proliferative state, degradation of the mitochondrial substrate SDHB, reduction in survivin and elevation in ATF4 (integrated stress response). Importantly, ONC-206 treatment induced significant cell death of patient-derived SHH, WNT, and Group 3 tumors ex vivo and Group 4 cells in vitro, while having no observable toxicity in normal brain. Efficacy studies of ONC-206 against MB in vivo will be reported in preparation for a planned Phase I study of ONC-206 in children with malignant brain tumors.

BIOM-60. BIOMARKER EVALUATION FOR IMIPRIDONE ONC206 REVEALS ClpP, ATF4, MYC, EGFR and HIF1 AS KEY PREDICTORS OF ANTI-CANCER EFFICACY

Abstract ONC206 is a DRD2 antagonist and ClpP agonist that is a chemical derivative of ONC201, which is in Phase II clinical trials for H3 K27M-mutant glioma. We have previously reported that dopamine receptor expression correlates with ONC201 and ONC206 efficacy. Here, we evaluated additional predictive biomarkers for both agents in the GDSC panel using RNA-seq expression data. ClpP emerged as a strong predictor of efficacy for ONC206 (IC50: p = 1.83E-4, AUC: 9.92E-13). ClpP activation enhances degradation of its substrates, including electron transport chain members responsible for oxidative phosphorylation (OXPHOS). Imipridones activate the integrated stress response involving ATF4 and cause proteasomal degradation of c-myc, which also reduces OXPHOS. Accordingly, high ATF4 (IC50: p = 4.92E-5, AUC: p=2.84E-9) and elevated c-myc correlated with ONC206 efficacy (IC50: p = 6.42E-6, AUC: 3.31E-12). EGFR expression is inversely correlate with DRD2 expression in glioma and its activation is associated with glycolysis. Low EGFR expression correlated with increased ONC206 efficacy (IC50: p = 4.32E-7, AUC: p = 6.44E-20). Loss of HIF1 shunts cellular metabolism toward OXPHOS. Low HIF1 expression correlated with increased anticancer efficacy for ONC206 (IC50: p = 1.96E-3, AUC: p = 1.56E-11). Expression of each of the five markers was significantly different in cell lines that achieved an IC90 with ONC206 (~10%) versus those that did not. A similar analysis for ONC201 revealed that ClpP, MYC and EGFR are more predictive of efficacy relative to ATF4 and HIF1. Combinatorial biomarker analyses revealed MYC/EGFR as the most significant predictor of IC50 for both agents. ClpP/MYC and ClpP/HIF1 were the most significant predictors of AUC for ONC201 and ONC206, respectively. Ongoing studies are further investigating tumor type enrichment of biomarkers. Prediction of innate imipridone sensitivity using biomarkers identified in this study may guide patient and tumor type selection in clinical trials.

BIOM-22. EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR) AS A MOLECULAR DETERMINANT OF GLIOBLASTOMA RESPONSE TO DOPAMINE RECEPTOR 2 (DRD2) INHIBITORS

Abstract BACKGROUND There are ongoing clinical trials exploring the efficacy of dopamine receptor 2 (DRD2) inhibition against glioblastomas, the most common primary brain tumor. Here we examine potential molecular determinants of this efficacy. METHODS The Cancer Genome Atlas (TCGA) glioblastoma database and other published mRNA profiles were used to analyze the DRD2 and EGFR expression pattern. In vitro and in vivo responses to DRD2 inhibitors were determined using patient derived xenograft (PDX) glioblastoma models. Immunohistochemical studies were performed on clinically annotated glioblastoma samples derived from patients treated with ONC201, a DRD2 inhibitor. RESULTS Analysis of clinical glioblastoma specimens derived from independent patient cohorts revealed an inverse correlation between EGFR and DRD mRNA expression, with implication that signaling mediated by these proteins shares overlapping functions. In independent panels of PDX glioblastoma lines, high EGFR expression was associated with poor in vitro and in vivo response to DRD2 inhibitors, including haloperidol and ONC201. Moreover, ectopic expression of a constitutively active EGFR, EGFRvIII, suppressed glioblastoma sensitivity to ONC201. DRD2 expression positively correlated with expression of rate-limiting enzymes for dopamine synthesis as well as dopamine secretion, suggesting contribution of autocrine DRD2 signaling. Analysis of specimens from patients treated with ONC201 (n = 15) showed an inverse correlation between the intensity of EGFR staining and clinical response. The median overall survival for patients with high and low EGFR staining was 162 and 373 days, respectively (p = 0.037). CONCLUSIONS High EGFR expression is a determinant of poor glioblastoma response to DRD2. This finding should inform future clinical trial designs.

EXTH-62. PRECLINICAL EFFICACY OF THE IMIPRIDONE ONC-206 AGAINST MEDULLOBLASTOMA

Abstract Treatment for medulloblastoma (MB) is typically ineffective for MYC amplified or metastatic SHH, Group 3 and 4 subgroups. Promising preclinical and clinical results have been obtained for adult and pediatric malignant glioma treated with ONC-201, a selective antagonist of DRD2, a G-protein coupled receptor that regulates prosurvival pathways. Herein, we report the activity of ONC-201 and ONC-206, which has increased non-competitive antagonism of DRD2, against MB. We treated three different MB cell types representative of SHH- and Group 3-like cells, with varied levels of DRD2 expression, and consistently observed increased cell death in a dose-dependent manner at lower doses of ONC-206 compared to ONC-201. We also evaluated ClpP as an additional drug target in MB. ClpP is a mitochondrial protease that has been shown to directly bind and be activated by ONC 201, and is highly expressed at the protein level across pediatric MB, malignant glioma and ATRT, but not normal brain. We observed that similar to ONC-201, ONC-206 treatment of MB cells induces the restoration of mitochondrial membrane potential to the non-proliferative state, degradation of the mitochondrial substrate SDHB, reduction in survivin and elevation in ATF4 (integrated stress response). Importantly, ONC-206 treatment induced significant cell death of patient-derived SHH, WNT, and Group 3 tumors ex vivo and Group 4 cells in vitro, while having no observable toxicity in normal brain. ONC-206 treatment of a transgenic mouse model of Shh MB in vivo significantly reduces tumor growth and doubles survival time in a dose-dependent manner following 2 weeks of therapy. Additional in vivo data will be reported in preparation for a planned Phase I study of ONC-206 in children with malignant brain tumors.

Uncovering the mechanisms of leech and centipede granules in the treatment of diabetes mellitus-induced erectile dysfunction utilising network pharmacology

Ethnopharmacological relevanceDiabetes mellitus-induced erectile dysfunction (DMED) is one of the most common complications of diabetes mellitus. Leech and centipede granules (LCG) have traditionally been used as blood-activating agents in various ethnomedicinal systems of East Asia, especially in China. It is often used to regulate bodily functions and considered as adjuvant therapy for promoting blood circulation, alleviating blood coagulation, activating meridians, and relieving stasis. Aim of the studyThis study aimed to identify potential genes and mechanisms of LCG on DMED from the network pharmacological perspective. Materials and methodsThe active components of LCG were identified by UHPLC-Q-TOF-MS, TCMID, and the BATMAN-TCM databases, and the disease targets of DMED were obtained from the DisGeNET, CooLGeN, GeneCards databases. After identifying DMED targets of LCG, a protein-protein interaction (PPI) network was constructed. Hub genes and significant modules were identified via the MCODE plug-in of Cytoscape software. Then, significant signaling pathways of the modules were identified using the Metascape database. The probable interaction mode of compounds-hub genes is examined using Molecular Operating Environment (MOE) docking software. Besides, we investigated the effects and mechanisms of LCG on improving erectile function in the streptozotocin (STZ)-induced diabetic rats model. ResultsCombined UHPLC-Q-TOF-MS analysis with network pharmacology study, 18 active compounds were selected for target prediction. There are 97 common target genes between LCG and DMED. Enrichment of the KEGG pathway mainly involves in the calcium signaling pathway, NF-kappa B signaling pathway, cGMP-PKG signaling pathway, HIF-1 signaling pathway, PI3K-Akt signaling pathway, and mTOR signaling pathway. Nine hub genes were regulated by LCG in DMED, including CXCL8, NOS3, CRH, TH, BDNF, DRD4, ACE, CNR1, and HTR1A. The results of molecular docking analysis showed that the tyrosin, ursolic acid, and L-Histidine has a relatively stable interaction with corresponding hub genes via generating hydrogen bonds, H-π, and π-π interactions. Significantly, the results in docking predicted a higher affinity of vardenafil to the hub genes compared to the tyrosin, ursolic acid, and L-Histidine. Furthermore, LCG increased the testosterone, erection frequency, the ratio of ICP and MAP, SOD, cGMP, cAMP as well as decreased the MDA, and AGEs expression levels. And, LCG ameliorated the histological change of penile tissues in DMED rats. Hence, LCG attenuates oxidative stress, increases NO production; For the mechanism exploration, LCG could significantly upregulate the mRNA and protein expression of CNR1, NOS3, CRH, TH, BDNF, and DRD4, whereas CXCL8, ACE, and HTR1A levels were significantly higher than those in the DMED group. Moreover, LCG activates the NO/cGMP/PKG pathway, PI3K/Akt/nNOS pathway, cAMP/PKA pathway, and inhibits the HIF-1α/mTOR pathway to improve erectile function. ConclusionsOur results suggest that LCG maybe offer a new therapeutic basis for the treatment of DMED via altering the gene expression of involved metabolic pathways.

Investigation of DRD2 and HTR2A mRNA Expression in Two Therapeutic States of Antipsychotic Polypharmacy and Aripiprazole Monotherapy in the Peripheral Blood of Patients With Schizophrenia

Objectives: Schizophrenia is a severe psychiatric disorder that has profound effects on both individuals and the community. Notwithstanding the suggestion for treating schizophrenia with a minimum dose of drugs, antipsychotic polypharmacy increases the patient’s care costs and drug interactions. Aripiprazole reduces the metabolic side effects of antipsychotic polypharmacy treatment. DRD2 and HTR2A can serve as predictors for response to treatment in schizophrenic patients. The purpose of this survey was to measure the DRD2 and HTR2A genes expression in the peripheral blood samples using Real-Time Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Methods: A total of 19 patients with a long history of schizophrenia who received at least two types of antipsychotics with daily doses of more than 500 mg of chlorpromazine were entered into the study. The response rates to the treatment based on scores in the Brief Psychiatric Rating Scale (BPRS) questionnaire and DRD2 and HTR2A expression were compared between antipsychotic polypharmacy status and 6 months after monotherapy with aripiprazole. Results: The levels of DRD2 expression decreased significantly after the intervention. The mean changes in HTR2A expression and the BPRS questionnaire and also the relationship between changes in DRD2 and HTR2A expression and changes in BPRS score after the intervention were not significant. Discussion: The conversion of the antipsychotic polypharmacy state to monotherapy with aripiprazole has been accompanied by a significant decrease in DRD2A expression. These genes can be used for evaluating the response rate of schizophrenia treatments in the future.

Expression of Dopamine-Related Genes in Four Human Brain Regions.

A better understanding of dopaminergic gene expression will inform future treatment options for many different neurologic and psychiatric conditions. Here, we utilized the National Institutes of Health’s Genotype-Tissue Expression project (GTEx) dataset to investigate genotype by expression associations in seven dopamine pathway genes (ANKK1, DBH, DRD1, DRD2, DRD3, DRD5, and SLC6A3) in and across four human brain tissues (prefrontal cortex, nucleus accumbens, substantia nigra, and hippocampus). We found that age alters expression of DRD1 in the nucleus accumbens and prefrontal cortex, DRD3 in the nucleus accumbens, and DRD5 in the hippocampus and prefrontal cortex. Sex was associated with expression of DRD5 in substantia nigra and hippocampus, and SLC6A3 in substantia nigra. We found that three linkage disequilibrium blocks of SNPs, all located in DRD2, were associated with alterations in expression across all four tissues. These demographic characteristic associations and these variants should be further investigated for use in screening, diagnosis, and future treatment of neurological and psychiatric conditions.

Association of dopamine D2/3 receptor binding potential measured using PET and [11C]-(+)-PHNO with post-mortem DRD2/3 gene expression in the human brain

Open access post-mortem transcriptome atlases such as the Allen Human Brain Atlas (AHBA) can inform us about mRNA expression of numerous proteins of interest across the whole brain, while in vivo protein binding in the human brain can be quantified by means of neuroreceptor positron emission tomography (PET). By combining both modalities, the association between regional gene expression and receptor distribution in the living brain can be approximated. Here, we compare the characteristics of D2 and D3 dopamine receptor distribution by applying the dopamine D2/3 receptor agonist radioligand [11C]-(+)-PHNO and human gene expression data. Since [11C]-(+)-PHNO has a higher affinity for D3 compared to D2 receptors, we hypothesized that there is a stronger relationship between D2/3 non-displaceable binding potentials (BPND) and D3 mRNA expression. To investigate the relationship between D2/3 BPND and mRNA expression of DRD2 and DRD3 we performed [11C]-(+)-PHNO PET scans in 27 healthy subjects (12 females) and extracted gene expression data from the AHBA. We also calculated D2/D3 mRNA expression ratios to imitate the mixed D2/3 signal of [11C]-(+)-PHNO. In accordance with our a priori hypothesis, a strong correlation between [11C]-(+)-PHNO and DRD3 expression was found. However, there was no significant correlation with DRD2 expression. Calculated D2/D3 mRNA expression ratios also showed a positive correlation with [11C]-(+)-PHNO binding, reflecting the mixed D2/3 signal of the radioligand. Our study supports the usefulness of combining gene expression data from open access brain atlases with in vivo imaging data in order to gain more detailed knowledge on neurotransmitter signaling.