Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing.

Supporting cell proliferation through nucleotide biosynthesis is an essential requirement for cancer cells. Hence, inhibition of folate-mediated one carbon (1C) metabolism, which is required for nucleotide synthesis, has been successfully exploited in anti-cancer therapy. Here, we reveal that mitochondrial folate metabolism is upregulated in patient-derived leukaemic stem cells (LSCs). We demonstrate that inhibition of mitochondrial 1C metabolism through impairment of de novo purine synthesis has a cytostatic effect on chronic myeloid leukaemia (CML) cells. Consequently, changes in purine nucleotide levels lead to activation of AMPK signalling and suppression of mTORC1 activity. Notably, suppression of mitochondrial 1C metabolism increases expression of erythroid differentiation markers. Moreover, we find that increased differentiation occurs independently of AMPK signalling and can be reversed through reconstitution of purine levels and reactivation of mTORC1. Of clinical relevance, we identify that combination of 1C metabolism inhibition with imatinib, a frontline treatment for CML patients, decreases the number of therapy-resistant CML LSCs in a patient-derived xenograft model. Our results highlight a role for folate metabolism and purine sensing in stem cell fate decisions and leukaemogenesis.

Ribociclib plus Endocrine Therapy in Early Breast Cancer.

BACKGROUND: Ribociclib has been shown to have a significant overall survival benefit in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer is unclear. METHODS: In this international, open-label, randomized, phase 3 trial, we randomly assigned patients with HR-positive, HER2-negative early breast cancer in a 1:1 ratio to receive ribociclib (at a dose of 400 mg per day for 3 weeks, followed by 1 week off, for 3 years) plus a nonsteroidal aromatase inhibitor (NSAI; letrozole at a dose of 2.5 mg per day or anastrozole at a dose of 1 mg per day for ≥5 years) or an NSAI alone. Premenopausal women and men also received goserelin every 28 days. Eligible patients had anatomical stage II or III breast cancer. Here we report the results of a prespecified interim analysis of invasive disease-free survival, the primary end point; other efficacy and safety results are also reported. Invasive disease-free survival was evaluated with the use of the Kaplan-Meier method. The statistical comparison was made with the use of a stratified log-rank test, with a protocol-specified stopping boundary of a one-sided P-value threshold of 0.0128 for superior efficacy. RESULTS: As of the data-cutoff date for this prespecified interim analysis (January 11, 2023), a total of 426 patients had had invasive disease, recurrence, or death. A significant invasive disease-free survival benefit was seen with ribociclib plus an NSAI as compared with an NSAI alone. At 3 years, invasive disease-free survival was 90.4% with ribociclib plus an NSAI and 87.1% with an NSAI alone (hazard ratio for invasive disease, recurrence, or death, 0.75; 95% confidence interval, 0.62 to 0.91; P = 0.003). Secondary end points - distant disease-free survival and recurrence-free survival - also favored ribociclib plus an NSAI. The 3-year regimen of ribociclib at a 400-mg starting dose plus an NSAI was not associated with any new safety signals. CONCLUSIONS: Ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III early breast cancer. (Funded by Novartis; NATALEE ClinicalTrials.gov number, NCT03701334.).

Duvelisib: A comprehensive profile.

Duvelisib (DUV) is chemically named as (S)-3-(1-((9H-Purin-6-yl)amino)ethyl)-8-chloro-2-phenylisoquinolin-1(2H)-one. It is a novel drug with a small molecular weight and characterized by dual phosphoinositide-3-kinase (PI3K)- and PI3K-inhibitory activity. The Food and Drug Administration (FDA) recently approved DUV for the management of small lymphocytic lymphoma (SLL) and relapsed or refractory chronic lymphocytic leukemia (CLL) in adult patients. DUV is marketed under the brand name of Copiktra® (Verastem, Inc., Needham, MA, USA). This chapter provides a critical extensive review of the literature, the description of DUV in terms of its names, formulae, elemental composition, appearance, and use in the treatment of CLL, SLL, and follicular lymphoma. The chapter also describes the methods for preparation of DUV, its physical-chemical properties, analytical methods for its determination, pharmacological properties, and dosing information.

Therapeutic drug monitoring in inflammatory bowel disease: A practical approach.

The global burden of inflammatory bowel diseases (IBD) is estimated at 4.9 million and the global prevalence exceeds 0.3%. Multiple newer therapeutic agents have broadened the options for the therapy of IBD in the last three decades. Thiopurines, however, have retained their place as maintenance therapy in IBD, especially in resource-constrained setting. But thiopurines have narrow therapeutic range, often needing discontinuation due to side effects or lack of efficacy. Biologic agents revolutionized the treatment of IBD, but the efficacy is lost in 50% of patient after one year. These outcomes are often due to inadequate drug concentrations that may lead to the development of antibodies as well as pharmacodynamic failure. Therapeutic drug monitoring (TDM) was proposed to reduce loss of response and to optimize the therapy in patients on thiopurine and biologic therapy. TDM is based on exposure-response relationship, suggesting a positive correlation between elevated serum anti-TNF concentrations and favorable therapeutic outcomes. TDM has multiple facets. This article discusses the benefits, evidence and limitations of TDM. The practical use of TDM in clinical practice is highlighted. Newer developments in the field and their relevance in practice are discussed.

Infliximab for maintenance of medically-induced remission in Crohn's disease.

BACKGROUND: Infliximab is a monoclonal antibody that binds and neutralises tumour necrosis factor-alpha (TNF-α) which is present in high levels in the blood serum, mucosa and stool of patients with Crohn's disease. OBJECTIVES: To determine the efficacy and safety of infliximab for maintaining remission in patients with Crohn's disease. SEARCH METHODS: On 31 August, 2021 and 23 June, 2023, we searched CENTRAL, Embase, MEDLINE, ClinicalTrials.gov, and WHO ICTRP. SELECTION CRITERIA: Randomised controlled trials (RCTs) in which infliximab was compared to placebo or another active comparator for maintenance, remission, or response in patients with Crohn's disease. DATA COLLECTION AND ANALYSIS: Pairs of review authors independently selected studies and conducted data extraction and risk of bias assessment. We expressed outcomes as risk ratios and mean differences with 95% confidence intervals. We assessed the certainty of the evidence using GRADE. Our primary outcome was clinical relapse. Secondary outcomes were loss of clinical response, endoscopic relapse, and withdrawal due to serious and adverse events. MAIN RESULTS: Nine RCTs with 1257 participants were included. They were conducted between 1999 and 2022; seven RCTs included biologically-naive patients, and the remaining two included a mix of naive/not naive patients. Three studies included patients in clinical remission, five included patients with a mix of activity scores, and one study included biologic responders with active disease at baseline. All studies allowed some form of concomitant medication during their duration. One study exclusively included patients with fistulating disease. The age of the participants ranged from 18 to 69 years old. All but one single-centre RCT were multicentre RCTs. Four studies were funded by pharmaceutical companies, two had a mix of commercial and public funding, and two had public funding. Infliximab is probably superior to placebo in preventing clinical relapse in patients who have mixed levels of clinical disease activity at baseline, and are not naive to biologics (56% vs 75%, RR 0.73, 95% CI 0.63 to 0.84, NNTB = 5, moderate-certainty evidence). We cannot draw any conclusions on loss of clinical response (RR 0.59, 95% CI 0.37 to 0.96), withdrawals due to adverse events (RR 0.66, 95% CI 0.37 to 1.19), or serious adverse events (RR 0.60, 95% CI 0.36 to 1.00) because the evidence is very low certainty. Infliximab combined with purine analogues is probably superior to purine analogues for clinical relapse (12% vs 59%, RR 0.20, 95% CI 0.10 to 0.42, NNTB = 2, moderate-certainty evidence), for patients in remission, and who are not naive to biologics. We cannot draw any conclusions on withdrawals due to adverse events (RR 0.47, 95% CI 0.15 to 1.49), and serious adverse events (RR 1.19, 95% CI 0.54 to 2.64) because the evidence is very low certainty. We cannot draw any conclusions about the effects of infliximab on serious adverse events compared to purine analogues (RR 0.79, 95% CI 0.37 to 1.68) for a population in remission at baseline because the evidence is very low certainty. There was no evidence available for the outcomes of clinical relapse, loss of clinical response, and withdrawal due to adverse events. Infliximab may be equivalent to biosimilar for clinical relapse (47% vs 40% RR 1.18, 95% CI 0.82 to 1.69), and it may be slightly less effective in averting loss of clinical response (49% vs 32%, RR 1.50, 95% CI 1.01 to 2.23, low-certainty evidence), for a population with mixed/low disease activity at baseline. Infliximab may be less effective than biosimilar in averting withdrawals due to adverse events (27% vs 0%, RR 20.73, 95% CI 2.86 to 150.33, low-certainty evidence). Infliximab may be equivalent to biosimilar for serious adverse events (10% vs 10%, RR 0.99, 95% CI 0.39 to 2.50, low-certainty evidence). We cannot draw any conclusions on the effects of subcutaneous biosimilar compared with intravenous biosimilar on clinical relapse (RR 1.01, 95% CI 0.65 to 1.57), loss of clinical response (RR 0.94, 95% CI 0.70 to 1.25), and withdrawals due to adverse events (RR 0.77, 95% CI 0.30 to 1.97) for an active disease population with clinical response at baseline because the evidence is of very low certainty. We cannot draw any conclusions on the effects of infliximab compared to adalimumab on loss of clinical response (RR 0.68, 95% CI 0.29 to 1.59), withdrawals due to adverse events (RR 0.10, 95% CI 0.01 to 0.72), serious adverse events (RR 0.09, 95% CI 0.01 to 1.54) for an active disease population with clinical response at baseline because the evidence is of very low certainty. There was no evidence available for the outcome of clinical relapse. AUTHORS' CONCLUSIONS: Infliximab is probably more effective in preventing clinical relapse than placebo (moderate-certainty evidence). Infliximab in combination with purine analogues is probably more effective in preventing clinical and endoscopic relapse than purine analogues alone (moderate-certainty evidence). No conclusions can be drawn regarding prevention of loss of clinical response, occurrence of withdrawals due to adverse events, or total adverse events due to very low-certainty evidence for both of these comparisons. There may be little or no difference in prevention of clinical relapse, withdrawal due to adverse events or total adverse events between infliximab and a biosimilar (low-certainty evidence). Infliximab may lead to more loss of clinical response than a biosimilar (low-certainty evidence). We were unable to draw meaningful conclusions about other comparisons and outcomes related to missing data or very low-certainty evidence due to serious concerns about imprecision and risk of bias. Further research should focus on comparisons with other active therapies for maintaining remission, as well as ensuring adequate power calculations and reporting of methods.

The Effect of Renal Replacement Therapy in a Patient with Mercaptopurine Toxicity: Time to Revise Guidelines.

INTRODUCTION: Mercaptopurine, a thiopurine, is used in various disorders of immune regulation, such as autoimmune hepatitis. Thiopurine metabolism is complex with risk for overdosing, especially when metabolism is impaired by liver dysfunction. Hepatotoxicity may be due to mercaptopurine overdose and is often reversible after prompt cessation of the drug. CASE PRESENTATION: Treatment of thiopurine toxicity is mainly supportive and literature on enhanced elimination by renal replacement therapy is ambiguous. CONCLUSION: In this case of thiopurine toxicity, a patient with autoimmune hepatitis presents with abdominal pain, nausea, vomiting, and diarrhea. We show in this case report that renal replacement therapy had no effect on total body clearance of mercaptopurine.

Enhancing anti-AML activity of venetoclax by isoflavone ME-344 through suppression of OXPHOS and/or purine biosynthesis in vitro.

Venetoclax (VEN), in combination with low dose cytarabine (AraC) or a hypomethylating agent, is FDA approved to treat acute myeloid leukemia (AML) in patients who are over the age of 75 or cannot tolerate standard chemotherapy. Despite high response rates to these therapies, most patients succumb to the disease due to relapse and/or drug resistance, providing an unmet clinical need for novel therapies to improve AML patient survival. ME-344 is a potent isoflavone with demonstrated inhibitory activity toward oxidative phosphorylation (OXPHOS) and clinical activity in solid tumors. Given that OXPHOS inhibition enhances VEN antileukemic activity against AML, we hypothesized that ME-344 could enhance the anti-AML activity of VEN. Here we report that ME-344 enhanced VEN to target AML cell lines and primary patient samples while sparing normal hematopoietic cells. Cooperative suppression of OXPHOS was detected in a subset of AML cell lines and primary patient samples. Metabolomics analysis revealed a significant reduction of purine biosynthesis metabolites by ME-344. Further, lometrexol, a purine biosynthesis inhibitor, synergistically enhanced VEN-induced apoptosis in AML cell lines. Interestingly, AML cells with acquired AraC resistance showed significantly increased purine biosynthesis metabolites and sensitivities to ME-344. Furthermore, synergy between ME-344 and VEN was preserved in these AraC-resistant AML cells. In vivo studies revealed significantly prolonged survival upon combination therapy of ME-344 and VEN in NSGS mice bearing parental or AraC-resistant MV4-11 leukemia compared to the vehicle control. This study demonstrates that ME-344 enhances VEN antileukemic activity against preclinical models of AML by suppressing OXPHOS and/or purine biosynthesis.

[Efficacy of Sildenafil oral spray for the treatment of erectile dysfunction in patients with type 2 diabetes mellitus and prediabetes].

AIM: To evaluate the results of using Sildenafil in the form of an oral spray (Gent) for the treatment of erectile dysfunction (ED) in men with type 2 diabetes mellitus (DM) and prediabetes. MATERIAL AND METHODS: A total of 60 patients were divided into two groups of 30 people. The group 1 included patients with prediabetes, while group 2 consisted of patients with type 2 DM. All men had proven ED. The severity of ED was assessed using the International Index of Erectile Function (IIEF-5). To assess the state of penile blood flow, all patients underwent Doppler ultrasound before and after treatment. Patients with prediabetes used Sildenafil in the form of oral spray (Gent) 25 mg (2 doses) 1 time per day for 1 month, patients with type 2 diabetes received 50 mg (4 injections) every other day for 1 month. In addition, most of the subjects took metformin and followed diet therapy. RESULTS: In patients of both groups, the administration of Sildenafil oral spray led to a decrease in body weight, waist circumference, a decrease in insulin and Hemoglobin A1C level without changing of hypoglycemic therapy in those with type 2 DM. In men with prediabetes, a decrease in fasting insulin levels was found. During treatment, half of the persons with impaired glucose metabolism had an increase in the testosterone level. According to IIEF-5, a decrease in the severity of ED in both groups of patients was seen. In men with prediabetes, the average IIEF-5 score increased from 15.98 to 21.57 points (p<0.05), while in patients with type 2 DM it improved from 12.18 to 18.44 points (p<0.05). Doppler ultrasound indicated a significant increase in the maximum systolic blood flow velocity and arterial resistivity index after treatment with Sildenafil oral spray in patients with both prediabetes and type 2 diabetes. CONCLUSION: Sildenafil oral spray can be effectively used for the treatment of ED in men with type 2 DM and prediabetes.

Honey Mushroom, Armillaria mellea (Agaricomycetes) and Its Fermentation Products Target Regulation of OAT1/OAT3 Proteins to Reduce Hyperuricemia in Mice.

BACKGROUND: Disorders of purine metabolism are the main cause of hyperuricemia. Current drugs for the treatment of hyperuricemia usually cause a degree of cardiovascular damage. METHODS: This study aimed to investigate the therapeutic effects of Armillaria mellea fruiting body (AFB), Armillaria rhizomorph (AR) and Armillaria mellea fermentation product (after rhizomorphs removal) (AFP) on hyperuricemic mice. The hyperuricemia mouse model was established by oral administration of potassium oxonate 0.9 g⋅kg-1 and hypoxanthine 0.5 g⋅kg-1 for two weeks. Starting from the third week, the intragastric administration of the intervention drug group was as follows: Allopurinol 0.013 g⋅kg-1, AFB (3.9 and 7.8 g⋅kg-1), AR (3.9 and 7.8 g⋅kg-1), AFP (1.95 and 3.9 g⋅kg-1) once daily for 14 days. RESULTS: Results showed that AFB, AR, and AFP reduced the contents of serum uric acid, serum creatinine, and blood urea nitrogen in hyperuricemic mice and the mechanism of action might be through up-regulation of the expression levels of organic anion transporter 1/organic anion transporter 3 proteins in kidney tissue. AR and AFP both exhibited better uric acid-lowering effects than AFB, which may be due to the higher purine content of AFB. CONCLUSIONS: Armillaria mellea and its fermentation products can treat hyperuricemia by up-regulating OAT1 protein and OAT3 protein, reducing uric acid content in mice.

Bipolar mania and epilepsy pathophysiology and treatment may converge in purine metabolism: A new perspective on available evidence.

Decreased ATPergic signaling is an increasingly recognized pathophysiology in bipolar mania disease models. In parallel, adenosine deficit is increasingly recognized in epilepsy pathophysiology. Under-recognized ATP and/or adenosine-increasing mechanisms of several antimanic and antiseizure therapies including lithium, valproate, carbamazepine, and ECT suggest a fundamental pathogenic role of adenosine deficit in bipolar mania to match the established role of adenosine deficit in epilepsy. The depletion of adenosine-derivatives within the purine cycle is expected to result in a compensatory increase in oxopurines (uric acid precursors) and secondarily increased uric acid, observed in both bipolar mania and epilepsy. Cortisol-based inhibition of purine conversion to adenosine-derivatives may be reflected in observed uric acid increases and the well-established contribution of cortisol to both bipolar mania and epilepsy pathology. Cortisol-inhibited conversion from IMP to AMP as precursor of both ATP and adenosine may represent a mechanism for treatment resistance common in both bipolar mania and epilepsy. Anti-cortisol therapies may therefore augment other treatments both in bipolar mania and epilepsy. Evidence linking (i) adenosine deficit with a decreased need for sleep, (ii) IMP/cGMP excess with compulsive hypersexuality, and (iii) guanosine excess with grandiose delusions may converge to suggest a novel theory of bipolar mania as a condition characterized by disrupted purine metabolism. The potential for disease-modification and prevention related to adenosine-mediated epigenetic changes in epilepsy may be mirrored in mania. Evaluating the purinergic effects of existing agents and validating purine dysregulation may improve diagnosis and treatment in bipolar mania and epilepsy and provide specific targets for drug development.

Glutathione-Mediated Neuroprotective Effect of Purine Derivatives.

Numerous basic studies have reported on the neuroprotective properties of several purine derivatives such as caffeine and uric acid (UA). Epidemiological studies have also shown the inverse association of appropriate caffeine intake or serum urate levels with neurodegenerative diseases such as Alzheimer disease (AD) and Parkinson's disease (PD). The well-established neuroprotective mechanisms of caffeine and UA involve adenosine A2A receptor antagonism and antioxidant activity, respectively. Our recent study found that another purine derivative, paraxanthine, has neuroprotective effects similar to those of caffeine and UA. These purine derivatives can promote neuronal cysteine uptake through excitatory amino acid carrier protein 1 (EAAC1) to increase neuronal glutathione (GSH) levels in the brain. This review summarizes the GSH-mediated neuroprotective effects of purine derivatives. Considering the fact that GSH depletion is a manifestation in the brains of AD and PD patients, administration of purine derivatives may be a new therapeutic approach to prevent or delay the onset of these neurodegenerative diseases.

Synthesis and mechanism of action of new purine derivatives against triple negative breast cancer.

Triple negative breast cancer (TNBC) is considered to be the most difficult subtype of breast cancer to treat because of its extremely prone to metastasis and the lack of targeted therapy drugs. New purine derivatives were synthesized and evaluated in a series of kinases and cell lines. The most active compounds 3g and 3j were selected based on their antiproliferative activities, then their pharmaceutical activity and mechanism in MDA-MB-231 cells were analyzed. The results in vitro indicated that compounds 3g and 3j can induce MDA-MB-231 cells apoptosis, and inhibit its migration and angiogenesis through influencing protein expression such as Bcl-2, Bax, Bcl-xl, P38, MMP2, MMP9, AKT and EGFR. In vivo results indicate that compounds 3g and 3j can inhibit tumor growth and metastasis and reduce the expression of Ki67 and CD31 protein in TNBC xenograft models. These findings not only broaden our understanding of the anti-TNBC effects and mechanisms of compounds 3g and 3j, but also provide new ideas and reference directions for the treatment of TNBC.