Melva Louisa

in vitro Modulation of P-glycoprotein, MRP-1 and BCRP Expression by Mangiferin in Doxorubicin-Treated MCF-7 Cells

The multidrug resistance phenotype is one of the major problems in development of cancer cell resistance to chemotherapy. Some natural compounds from medicinal plants have demonstrated promising capacity in enhancing anticancer effects in drug resistant cancer cells. We aimed to investigate whether mangiferin might have an ability to re-sensitize MCF-7 breast cancer cells previously treated with short-term doxorubicin in vitro, through the modulation of efflux transporters, P-glycoprotein (P-gp), MRP1 and BCRP. We exposed MCF-7 breast cancer cells pretreated with doxorubicin for 10 days to mangiferin (10, 25 or 50 μM) for 96 hours. Afterwards, we evaluated influence on cell viability and level of mRNA expression of P-gp, MRP1 and BCRP. Doxorubicin given in combination with mangiferin at low concentrations (10 and 25 μM) failed to give significant reduction in cell viability, while at the highest concentrations, the combination significantly reduced cell viability. The mRNA expression analysis of P-gp, MRP1 and BCRP showed that mangiferin had inhibitory effects on P-gp but no effects on MRP1 and BCRP. In conclusion, we suggest that mangiferin at high concentrations can be used as chemosensitizer for doxorubicin therapy. This effect might be attributed by inhibitory effects of mangiferin on P-glycoprotein expression.

Lack of a relationship between the serum concentration of aminoglycosides and ototoxicity in neonates.

INTRODUCTION Gentamicin and the other aminoglycosides are toxic antibiotics, but they are urgently needed to treat newborns with neonatal sepsis. Aminoglycosides are well known for their nephrotoxicity and ototoxicity. The aminoglycoside dosage currently applied in Indonesia is derived from studies done in Caucasian populations. The safety and efficacy of this dosage regimen, however, has never been evaluated to date. The pharmacokinetic profile of drugs may vary between populations and this may be influenced by genetic factors, lifestyle, drug interactions, etc. The detection of aminoglycoside toxicity in newborns is usually problematic. The present study aims to know the proportion of ototoxicity in newborns in the Cipto Mangunkusumo Hospital treated with gentamicin or amikacin in relation to their trough serum concentration. METHODS The serum level of gentamicin and amikacin were quantified using Liquid Chromatography Tandem Mass Spectrometry (LC-MSMS), and is assumed to be safe if the trough serum concentrations are < 2 mcg/ml and effective if it is between 5 - 12 mcg/ml. For amikacin the desired trough serum concentrations are < 10 mcg/ml and the peak is between 20 - 30 mcg/ml. The hearing function was assessed by Distortion Product Otoacoustic Emission (DPOAE) instrument. This study is registered with the www.clinicaltrials.gov NCT01624324. CONCLUSION Our study indicated that there was no relationship between aminoglycosides serum trough concentration and ototoxicity in neonates with neonatal sepsis.

Confirmed Plasmodium vivax Resistance to Chloroquine in Central Vietnam

ABSTRACT Plasmodium vivax resistance to chloroquine (CQ) is currently reported in almost all countries where P. vivax is endemic. In Vietnam, despite a first report on P. vivax resistance to chloroquine published in the early 2000s, P. vivax was still considered sensitive to CQ. Between May 2009 and December 2011, a 2-year cohort study was conducted in central Vietnam to assess the recommended radical cure regimen based on a 10-day course of primaquine (0.5 mg/kg/day) together with 3 days of CQ (25 mg/kg). Here we report the results of the first 28-day follow-up estimating the cumulative risk of P. vivax recurrences together with the corresponding CQ blood concentrations, among other endpoints. Out of 260 recruited P. vivax patients, 240 completed treatment and were followed up to day 28 according to the WHO guidelines. Eight patients (3.45%) had a recurrent P. vivax infection, at day 14 (n = 2), day 21 (n = 1), and day 28 (n = 5). Chloroquine blood concentrations, available for 3/8 recurrent infections (days 14, 21, and 28), were above the MIC (>100 ng/ml whole blood) in all of these cases. Fever and parasitemia (both sexual and asexual stages) were cleared by day 3. Anemia was common at day 0 (35.8%), especially in children under 10 years (50%), and hemoglobin (Hb) recovery at day 28 was substantial among anemic patients (median change from day 0 to 28, +1.7 g/dl; interquartile range [IQR], +0.7 to +3.2). This report, based on CQ blood levels measured at the time of recurrences, confirms for the first time P. vivax CQ resistance in central Vietnam and calls for further studies using standardized protocols for accurately monitoring the extent and evolution of P. vivax resistance to chloroquine in Vietnam. These results, together with the mounting evidence of artemisinin resistance in central Vietnam, further highlight the increasing threat of antimalarial drug resistance to malaria elimination in Vietnam.

New Insight into the Molecular Drug Target of Diabetic Nephropathy

Diabetic nephropathy (DN) lowered quality of life and shortened life expectancy amongst those affected. Evidence indicates interaction between advanced glycation end products (AGEs), activated protein kinase C (PKC) and angiotensin II exacerbate the progression of DN. Inhibitors of angiotensin-converting enzyme (ACEIs), renin angiotensin aldosterone system (RAAS), AGEs, and PKC have been tested for slowing down the progression of DN. The exact molecular drug targets that lead to the amelioration of renal injury in DN are not well understood. This review summarizes the potential therapeutic targets, based on putative mechanism in the progression of the disease.

Cardioprotection mechanism of mangiferin on doxorubicin-induced rats: Focus on intracellular calcium regulation

Abstract Context: The molecular mechanism of doxorubicin (DOX) cardiotoxicity involves overproduction of free radicals that leads to intracellular calcium dysregulation and apoptosis. Mangiferin (MGR), a naturally occurring glucosylxanthone, has antioxidant and cardioprotective properties. However, its cardioprotection mechanism has yet to be revealed. Objective: This study determines whether the cardioprotective effect of MGR is caused by its effect on intracellular calcium regulation. Materials and methods: Male Sprague–Dawley rats were induced by DOX intraperitoneally with a total dose of 15 mg/kg bw. MGR was given orally at the doses of 30 and 60 mg/kg bw/d for seven consecutive weeks. The parameters examined were mRNA expression levels of proinflammatory cytokine gene (TNF-α), calcium regulatory gene (SERCA2a) and proapoptotic genes (caspase-9 and caspase-12), as well as cytosolic and mitochondrial calcium levels. Results: Treatment with MGR at 60 mg/kg bw/d significantly decreased the mRNA expression levels of TNF-α by 44.55% and caspase-9 by 52.79%, as well as the cytosolic calcium level by 24.15% (p < 0.05). SERCA2a and caspase-12 expressions were only slightly affected (27.27% increase and 24.85% decrease for SERCA2a and caspase-12, respectively, p > 0.05). Meanwhile, MGR 30 mg/kg bw/d gave insignificant results in all parameters. Discussion and conclusion: MGR protected against DOX-induced cardiac inflammation and apoptosis via down-regulation of proapoptotic and proinflammatory gene expressions, upregulation of SERCA2a gene expression, and normalization of cytosolic calcium level. Thus, the cardioprotective effect of MGR is at least in part due to the regulation of intracellular calcium homeostasis.

Anti-hepatitis C virus activity of a crude extract from longan ( Dimocarpus longan Lour.) leaves

Infection with hepatitis C virus (HCV) results in hepatitis C, a disease characterized by chronic infection, cirrhosis, and hepatocellular carcinoma. Currently, the standard therapy is a combination of pegylated interferon-α plus ribavirin with NS3 protease inhibitors. Addition of NS3 protease inhibitors to the standard therapy improves response rates; however, use of NS3 protease inhibitors is also associated with significant adverse effects and an increase in the overall cost of treatment. Therefore, there is a need to develop safe and inexpensive drugs for the treatment of HCV infections. In this study, we examined the antiviral activity of a crude extract from Dimocarpus longan leaves against HCV (genotype 2a strain JFH1). The D. longan crude extract (DL-CE) exhibited anti-HCV activity with a 50% effective concentration (EC50) of 19.4 μg/ml without cytotoxicity. A time-of-addition study demonstrated that DL-CE has anti-HCV activity at both the entry and post-entry steps and markedly blocks the viral entry step through direct virucidal activity with marginal inhibition of virion assembly. Co-treatment of DL-CE with cyclosporine A, an immunosuppressant or telaprevir, an NS3 protease inhibitor, resulted in additive and synergistic antiviral effects, respectively. Our findings suggest that DL-CE may be useful as an add-on therapy candidate for treating HCV infections.

Drug Efflux Transporters Are Overexpressed in Short-Term Tamoxifen-Induced MCF7 Breast Cancer Cells

Tamoxifen is the first line drug used in the treatment of estrogen receptor-positive (ER+) breast cancer. The development of multidrug resistance (MDR) to tamoxifen remains a major challenge in the treatment of cancer. One of the mechanisms related to MDR is decrease of drug influx via overexpression of drug efflux transporters such as P-glycoprotein (P-gp/MDR1), multidrug resistance associated protein (MRP), or BCRP (breast cancer resistance protein). We aimed to investigate whether the sensitivity of tamoxifen to the cells is maintained through the short period and whether the expressions of several drug efflux transporters have been upregulated. We exposed MCF7 breast cancer cells with tamoxifen 1 μM for 10 passages (MCF7 (T)). The result showed that MCF7 began to lose their sensitivity to tamoxifen from the second passage. MCF7 (T) also showed a significant increase in all transporters examined compared with MCF7 parent cells. The result also showed a significant increase of CC50 in MCF7 (T) compared to that in MCF7 (97.54 μM and 3.04 μM, resp.). In conclusion, we suggest that the expression of several drug efflux transporters such as P-glycoprotein, MRP2, and BCRP might be used and further studied as a marker in the development of tamoxifen resistance.

Differential expression of several drug transporter genes in HepG2 and Huh-7 cell lines

Background: Cell culture techniques have many advantages for investigation of drug transport to target organ like liver. HepG2 and Huh-7 are two cell lines available from hepatoma that can be used as a model for hepatic drug transport. The present study is aimed to analyze the expression level of several drug transporter genes in two hepatoma cell lines, HepG2 and Huh-7 and their response to inhibitors. Materials and Methods: This is an in vitro study using HepG2 and Huh-7 cells. The expression level of the following drug transporter genes was quantified: P-glycoprotein/multidrug resistance protein 1, Organic Anionic Transporter Protein 1B1 (OATP1B1) and Organic Cationic Transporter-1 (OCT1). Ribonucleic acid was extracted from the cells using Tripure isolation reagent, then gene expression level of the transporters is quantified using Applied Biosystems quantitative reverse transcriptase polymerase chain reaction. Verapamil (P-glycoprotein inhibitor), nelfinavir (OATP1B1 inhibitor), quinidine (OCT1 inhibitor) were used to differentiate the inhibitory properties of these agents to the transporter expressions in HepG2 and Huh-7 cells. Results: Huh-7 shows a higher level of P-glycoprotein, OATP1B1 and OCT1 expressions compared with those of HepG2. Verapamil reduces the expressions of P-glycoprotein in HepG2 and Huh-7; nelfinavir reduces the expression of OATP1B1 in HepG2 and Huh-7; while quinidine reduces the OCT1 gene expressions in HepG2, but not in Huh-7 cells. Conclusion: This study indicates that HepG2 might be a more suitable in vitro model than Huh-7 to study drug transport in hepatocytes involving drug transporters.

Association of Impaired Cytochrome P450 2D6 Activity Genotype and Phenotype With Therapeutic Efficacy of Primaquine Treatment for Latent Plasmodium vivax Malaria

Key Points Question How is natural variation in cytochrome P450 2D6 activity associated with therapeutic efficacy of primaquine phosphate against latent Plasmodium vivax malaria? Findings In this nested case-control study of 57 patients who had participated in a clinical trial of primaquine for radical cure of acute P vivax malaria, exposure to low levels of cytochrome P450 2D6 activity determined by genotype or measured by dextromethorphan metabolism phenotype was associated with a significantly increased likelihood of relapse of malaria in the year after directly observed high-dose primaquine therapy. Meaning Impaired cytochrome P450 2D6 activity was significantly associated with high risk of therapeutic failure of primaquine, and this finding suggests cytochrome P450 2D6 involvement in producing a therapeutically active metabolite.

Pre-Treatment with Curcumin Ameliorates Cisplatin-Induced Kidney Damage by Suppressing Kidney Inflammation and Apoptosis in Rats

OBJECTIVE In addition to oxidative stress, inflammation and apoptosis have an important role in the pathogenesis of cisplatin-induced kidney damage. This study aimed to investigate the molecular mechanisms of protective effects of curcumin against cisplatin-induced kidney inflammation and apoptosis in rats. MATERIALS AND METHODS Eighteen rats were equally divided into three groups; normal (0.5% CMC-Na), cisplatin (CDPP) (7 mg/kg i.p.), and cisplatin+curcumin (CMN100) groups. Curcumin was given at a dose of 100 mg/kg orally for nine days, starts one week before giving a single dose of cisplatin. Kidney and plasma were taken for analysis. RESULTS Cisplatin challenged rats demonstrated kidney injury as shown by reduced creatinine clearance, increased of plasma BUN, plasma creatinine, and kidney MDA, decreased of kidney GSH levels, and kidney histopathology alterations. Also, cisplatin increased ERK1/2 phosphorylation and NF-κB expression, which subsequently increased mRNA expression of TNF-α, IL-6, KIM-1, NGAL, and Bax/Bcl-2 ratio as well as decreased mRNA expression of IL-10 in kidney tissues. Pre-treatment with curcumin significantly ameliorated inflammation and apoptosis induced by cisplatin. In addition, curcumin downregulated Ctr1 and OCT2 drug transporters as compared to cisplatin group. Histopathological examination furthers confirmed the kidney damage protection effect of curcumin. CONCLUSIONS These data indicate that curcumin has nephroprotective properties against cisplatin-induced kidney damage in rats and this effect is associated with its anti-inflammatory and anti-apoptosis profiles, in addition to its antioxidant. Hence, curcumin may be useful for preventing kidney damage against cisplatin administration.