Efektivitas Agen Pendeplesi GSH pada Sitotoksisitas Cisplatin terhadap Sel Kanker: Systematic Literature Review

Cisplatin is one of chemotherapy agent for long cancer, ovarium cancer, gastric cancer, breast cancer, head-neck cancer. However, in the fact, the role of cisplatin does not always provide an optimal effect because it often appears cancer cell resistance phenomenon to cisplatin. This resistance condition occurs partly due to the inactive metabolite cause of conjugation reaction between cisplatin and GSH in cancer cells. Therefore, gluthathione (GSH) has an important role in controlling cisplatin resistance. This study aims to analyze some combination of cisplatin and the depletion agent of gluthathione (GSH) as a support for cisplatin activity in several types of cancer cells within in vitro scope. This study is prepared using systematic literature review method. Library search were carried out on two accredited international journals databases, namely PubMed and Science Direct with interval years of publication in 2011-2020. From 10 selected journals, it was shown that the use of GSH depletion agents could enhance the cytotoxic effect of cisplatin. This was analyzed based on data of the number measured GSH cells and the number of living cells (% cell viability) which gave a significant decrease. The result of research are expected to be able to provide information for the development of therapeutic agents on cisplatin as chemotherapy.

Polymorphisms of Genes Related to Phase-II Metabolism and the Resistance of Clopidogrel

Clopidogrel is one of the thienopyridine antiplatelet drugs commonly used as a prophylactic medication to prevent coagulation in vessels and cardiovascular events. The molecule of clopidogrel is metabolized in the liver via phase-I and phase-II metabolism pathways. The sulfenic acid clopidogrel metabolite undergoes phase-II metabolism through conjugation with glutathione by the glutathione-s-transferase (GST) to form a glutathione conjugate of clopidogrel (inactive metabolite). A glutaredoxin enzyme removes the glutathione conjugated with clopidogrel to form cis-thiol-clopidogrel. This review focused on the polymorphisms of genes related to phase-II metabolism during the clopidogrel bioactivation process. Overall, no well-controlled studies were done about the relationship between the clopidogrel bioactivation process and genes related to phase-II metabolism’s enzymes. Nevertheless, some polymorphisms of G6PD, GCLC, GCLM, GSS, GST, GSR, HK, and GLRX genes could be responsible for clopidogrel resistance due to low glutathione conjugate or glutaredoxin plasma levels. Studies needed to be concerned with the relationship between clopidogrel resistance and phase-II metabolism issues in the near future.

Pharmacokinetics and Pharmacodynamics of Salvinorin A and Salvia divinorum: Clinical and Forensic Aspects

Salvia divinorum Epling and Játiva is a perennial mint from the Lamiaceae family, endemic to Mexico, predominantly from the state of Oaxaca. Due to its psychoactive properties, S. divinorum had been used for centuries by Mazatecans for divinatory, religious, and medicinal purposes. In recent years, its use for recreational purposes, especially among adolescents and young adults, has progressively increased. The main bioactive compound underlying the hallucinogenic effects, salvinorin A, is a non-nitrogenous diterpenoid with high affinity and selectivity for the κ-opioid receptor. The aim of this work is to comprehensively review and discuss the toxicokinetics and toxicodynamics of S. divinorum and salvinorin A, highlighting their psychological, physiological, and toxic effects. Potential therapeutic applications and forensic aspects are also covered in this review. The leaves of S. divinorum can be chewed, drunk as an infusion, smoked, or vaporised. Absorption of salvinorin A occurs through the oral mucosa or the respiratory tract, being rapidly broken down in the gastrointestinal system to its major inactive metabolite, salvinorin B, when swallowed. Salvinorin A is rapidly distributed, with accumulation in the brain, and quickly eliminated. Its pharmacokinetic parameters parallel well with the short-lived psychoactive and physiological effects. No reports on toxicity or serious adverse outcomes were found. A variety of therapeutic applications have been proposed for S. divinorum which includes the treatment of chronic pain, gastrointestinal and mood disorders, neurological diseases, and treatment of drug dependence. Notwithstanding, there is still limited knowledge regarding the pharmacology and toxicology features of S. divinorum and salvinorin A, and this is needed due to its widespread use. Additionally, the clinical acceptance of salvinorin A has been hampered, especially due to the psychotropic side effects and misuse, turning the scientific community to the development of analogues with better pharmacological profiles.

Voclosporin: a novel calcineurin inhibitor without impact on mycophenolic acid in patients with SLE

Background An open-label phase 1 study was conducted to evaluate the effect of voclosporin on blood levels of mycophenolic acid (MPA, active moiety) and mycophenolic acid glucuronide (MPAG, pharmacologically inactive metabolite) following dosing with mycophenolate mofetil (MMF) in subjects with systemic lupus erythematosus (SLE) and to assess the safety and tolerability of the combination. Methods MMF was orally administered at a dose of 1 g BID for at least 28 days prior to the study and continued at the same dose throughout the study. Voclosporin was orally administered at a dose of 23.7 mg BID for seven consecutive days (Day 1 to Day 7), starting in the evening of Day 1 and ending with the morning dose on Day 7. Dense PK blood samplings were collected pre-dose in the morning and from 0.25 to 12 hours post-morning doses. Analyses were derived by non-compartmental methods. Results In 24 patients, MPA exposure (Cmax and AUC0-12) was similar in the presence and absence of voclosporin, with treatment ratios of 0.94 and 1.09, respectively (Cmax: 16.5 μg/mL [Day 1] vs.15.8 μg/mL [Day 7], AUC0-12: 39.1 μg.h/mL [Day 1] vs. 40.8 μg.h/mL [Day 7]. MPAG exposure showed a small increase in the presence of voclosporin (12% for Cmax and 27% for AUC0-12). Combination therapy was well tolerated. Conclusions There is no clinically meaningful interaction between voclosporin and MMF. As changes in exposure to MPA may affect efficacy and safety, these data confirm that voclosporin and MMF can be given concomitantly without the need for dose adjustment.

Impact of selected genetic factors on clopidogrel inactive metabolite level and antiplatelet response in patients after percutaneous coronary intervention

Background and objective Clopidogrel is frequently used as part of optimal dual antiplatelet therapy in high-bleeding risk patients with the acute coronary syndrome. The concentration of the inactive carboxylic acid metabolite of clopidogrel might be useful to evaluate the response to clopidogrel therapy. Therefore, we sought to correlate the inhibition of platelet aggregation with the plasma level of the inactive metabolite of clopidogrel in patients after percutaneous coronary interventions (PCI) and their associations with the most frequently studied genetic polymorphisms. For this purpose, the fast and simple HPLC method for determining the concentration of the inactive metabolite was developed. Methods The effect of CYP2C19, CYP3A4/5, ABCB1 and PON1 genes on the plasma inactive metabolite concentration of clopidogrel and the platelet aggregation was investigated in 155 patients before and after PCI. Results The concentration of the inactive metabolite of clopidogrel was not significantly different in the intermediate metabolizers (IM) of CYP2C19 compared with extensive metabolizers (EM) both before and after PCI, while inhibition of platelet aggregation was found to be significantly better in EM than in IM. The presence of the A allele at position 2677 in the ABCB1 gene was associated with a significantly lower concentration of inactive metabolite of clopidogrel before PCI. Conclusion The CYP2C19*2 allele was associated with decreased platelet reactivity during clopidogrel therapy before and after PCI. Simultaneous determination of platelet aggregation and concentration of the inactive clopidogrel metabolite may be useful in clinical practice to find the cause of adverse effects or insufficient treatment effect in patients chronically treated with clopidogrel.

15-Keto-PGE2 acts as a biased/partial agonist to terminate PGE2-evoked signaling

Prostaglandin E2 (PGE2) is well-known as an endogenous proinflammatory prostanoid synthesized from arachidonic acid by the activation of cyclooxygenase-2. E type prostanoid (EP) receptors are cognates for PGE2 that have four main subtypes: EP1 to EP4. Of these, the EP2 and EP4 prostanoid receptors have been shown to couple to Gαs-protein and can activate adenylyl cyclase to form cAMP. Studies suggest that EP4 receptors are involved in colorectal homeostasis and cancer development, but further work is needed to identify the roles of EP2 receptors in these functions. After sufficient inflammation has been evoked by PGE2, it is metabolized to 15-keto-PGE2. Thus, 15-keto-PGE2 has long been considered an inactive metabolite of PGE2. However, it may have an additional role as a biased and/or partial agonist capable of taking over the actions of PGE2 to gradually terminate reactions. Here, using cell-based experiments and in silico simulations, we show that PGE2-activated EP4 receptor–mediated signaling may evoke the primary initiating reaction of the cells, which would take over the 15-keto-PGE2–activated EP2 receptor–mediated signaling after PGE2 is metabolized to 15-keto-PGE2. The present results shed light on new aspects of 15-keto-PGE2, which may have important roles in passing on activities to EP2 receptors from PGE2-stimulated EP4 receptors as a “switched agonist.” This novel mechanism may be significant for gradually terminating PGE2-evoked inflammation and/or maintaining homeostasis of colorectal tissues/cells functions.

Pharmacokinetics and Dose Proportionality of Betahistine in Healthy Individuals

Betahistine dihydrochloride is widely used to reduce the severity and frequency of vertigo attacks associated with Ménière’s disease. Betahistine is an analogue of histamine, and is a weak histamine H1 receptor agonist and potent histamine H3 receptor antagonist. The recommended therapeutic dose for adults ranges from 24 to 48 mg given in doses divided throughout the day. Betahistine undergoes extensive first-pass metabolism to the major inactive metabolite 2-pyridyl acetic acid (2PAA), which can be considered a surrogate index for quantitation of the parent drug due to extremely low plasma levels of betahistine. The aim of the present investigation was to assess the pharmacokinetics and dose proportionality of betahistine in Arabic healthy adult male subjects under fasting conditions. A single dose of betahistine in the form of a 8, 16, or 24 mg tablet was administered to 36 subjects in randomized, cross-over, three-period, three-sequence design separated by a one week washout period between dosing. The pharmacokinetic parameters Cmax, AUC0–t, AUC0–∞, Tmax, and Thalf were calculated for each subject from concentrations of 2-PAA in plasma, applying non-compartmental analysis. The current study demonstrated that betahistine showed linear pharmacokinetics (dose proportionality) in an Arabic population over the investigated therapeutic dose range of 8–24 mg.

Disulfiram (DSF) pharmacokinetics (PK) and copper PET imaging in a phase Ib study of intravenous (IV) copper loading with oral DSF for patients with metastatic castration-resistant prostate cancer (mCRPC).

96 Background: In preclinical models of prostate cancer (PC), DSF reduced tumor growth when co-administered with copper (Cu). Further, intracellular Cu uptake is partially regulated by androgen-receptor signaling. Given these data, we conducted a phase Ib clinical trial of mCRPC patients (pts) receiving Cu with DSF. Methods: Pts with mCRPC were assigned to 1 of 3 cohorts: neuroendocrine PC (NEPC) (A), adenocarcinoma (adenoCA) mCRPC with non-liver/peritoneal metastases (B), and adenoCA mCRPC with liver and/or peritoneal metastases (C). IV CuCl2 was given weekly for 3 doses with oral daily DSF. After CuCl2 dosing, daily oral Cu gluconate was started and DSF continued until disease progression as defined by Prostate Cancer Working Group Three (PCWG3). DSF and metabolite MeDDC levels in plasma were sampled at 0, 2, 4, 6 and 8 hours after the first dose and on Cycle 2 Day 1, and measured by HPLC. DSF and MeDDC were evaluated for cytotoxicity in 3 PC cell lines (22Rv1, LnCAP, and PC3) and a prostate epithelial cell line (PWR-1E). mCRPC Cu avidity was measured by 64Cu PET scan at baseline for all pts. Results: We treated 9 pts with mCRPC, 6 on cohort B and 3 on cohort C. No confirmed PSA declines or radiographic responses were observed in either cohort. Common adverse events included fatigue and psychomotor depression; no grade 4/5 AEs were observed. PK analysis: No DSF was detected in plasma (LOQ = 0.032 ng/mL, LOD = 0.01 ng/mL), whereas MeDDC was measurable in all study samples (LOQ = 0.512 ng/mL). MeDDC exhibited no cytotoxicity activity in PC cell lines. On 64Cu PET scans, bone metastases showed differential and heterogeneous Cu uptake. Lymph node and pulmonary metastases were evaluable, but not liver metastases due to significant Cu uptake in the liver. Conclusions: Oral DSF is not an effective treatment for mCRPC because it is quickly metabolized into the non-cytotoxic inactive metabolite, MeDDC. As such, this trial has stopped enrollment. Further work is needed to identify a stable DSF formulation so that the conditional lethality of Cu and DSF may be evaluated for treatment of mCRPC. Clinical trial information: NCT02963051.

Blood glutamate scavenging as a novel glutamate-based therapeutic approach for post-stroke depression

Post-stroke depression (PSD) is a major complication of stroke that significantly impacts functional recovery and quality of life. While the exact mechanism of PSD is unknown, recent attention has focused on the association of the glutamatergic system in its etiology and treatment. Minimizing secondary brain damage and neuropsychiatric consequences associated with excess glutamate concentrations is a vital part of stroke management. The blood glutamate scavengers, oxaloacetate and pyruvate, degrade glutamate in the blood to its inactive metabolite, 2-ketoglutarate, by the coenzymes glutamate–oxaloacetate transaminase (GOT) and glutamate–pyruvate transaminase (GPT), respectively. This reduction in blood glutamate concentrations leads to a subsequent shift of glutamate down its concentration gradient from the blood to the brain, thereby decreasing brain glutamate levels. Although there are not yet any human trials that support blood glutamate scavengers for clinical use, there is increasing evidence from animal research of their efficacy as a promising new therapeutic approach for PSD. In this review, we present recent evidence in the literature of the potential therapeutic benefits of blood glutamate scavengers for reducing PSD and other related neuropsychiatric conditions. The evidence reviewed here should be useful in guiding future clinical trials.