Zidovudine Research Articles

Surmounting Cytarabine-resistance in acute myeloblastic leukemia cells and specimens with a synergistic combination of hydroxyurea and azidothymidine

Acute myeloid leukemia (AML) patients display dismal prognosis due to high prevalence of refractory and relapsed disease resulting from chemoresistance. Treatment protocols, primarily based on the anchor drug Cytarabine, remained chiefly unchanged in the past 50 years with no standardized salvage regimens. Herein we aimed at exploring potential pre-clinical treatment strategies to surmount Cytarabine resistance in human AML cells. We established Cytarabine-resistant sublines derived from human leukemia K562 and Kasumi cells, and characterized the expression of Cytarabine-related genes using real-time PCR and Western blot analyses to uncover the mechanisms underlying their Cytarabine resistance. This was followed by growth inhibition assays and isobologram analyses testing the sublines’ sensitivity to the clinically approved drugs hydroxyurea (HU) and azidothymidine (AZT), compared to their parental cells. All Cytarabine-resistant sublines lost deoxycytidine kinase (dCK) expression, rendering them refractory to Cytarabine. Loss of dCK function involved dCK gene deletions and/or a novel frameshift mutation leading to dCK transcript degradation via nonsense-mediated decay. Cytarabine-resistant sublines displayed hypersensitivity to HU and AZT compared to parental cells; HU and AZT combinations exhibited a marked synergistic growth inhibition effect on leukemic cells, which was intensified upon acquisition of Cytarabine-resistance. In contrast, HU and AZT combination showed an antagonistic effect in non-malignant cells. Finally, HU and AZT synergism was demonstrated on peripheral blood specimens from AML patients. These findings identify a promising HU and AZT combination for the possible future treatment of relapsed and refractory AML, while sparing normal tissues from untoward toxicity.

Expression and Characterization of YoaA, a Putative Helicase in Bacteria, Involved in Repairing Blocks to DNA Replication

While cells have efficient pathways for repairing damage to DNA, some DNA damage avoids repair and is found in DNA replication. Because the DNA polymerases that replicate the genome are high fidelity enzymes, DNA damage blocks DNA synthesis and ultimately progression of the replication fork. It is known that cells would not be able to survive without mechanisms to repair these replication blocks and to restart replication. With a genetic screen, our collaborators at Lovett laboratory, using 3’azidothymidine (AZT) as a tool to inhibit replication, identified a novel gene in Escherichia coli, yoaA, which was required along with holC to provide cells with tolerance to AZT. HolC is a protein subunit of the E.coli DNA polymerase III holoenzyme that does the bulk of synthesis during DNA replication, and yoaA binds HolC. Based on sequence, the yoaA gene encodes an iron-sulfur (Fe-S) helicases. E.coli contains a second Fe-S helicase, DinG, and human cells contain four Fe-S helicases, XPD, FANCJ, RTEL1, and ChlR1, that are involved in DNA repair. The overall goal of this project is to express YoaA protein in soluble form and characterize its biochemical activities to determine how YoaA aids in DNA replication fork repair. In our initial studies, we made fluorescent labeled DNA for helicase assays and tested them which allowed us to work towards our long term goals of determining: 1) whether YoaA is DNA helicase and what are the best substrates for YoaA, and 2) how HolC affects YoaA activities. We have subcloned the yoaA gene into different expression vectors to express YoaA with and without affinity tags, and to co-express YoaA with HolC. We are developing strategies to purify YoaA alone and in a complex with HolC. We have subcloned the yoaA gene into different expression vectors to express yoaA with pCOLADuet. We are developing strategies to purify YoaA alone. The initial results working towards this are presented.

Urinary bactericidal activity of colistin and azidothymidine combinations against mcr-1-positive colistin-resistant Escherichia coli

A phase 1 clinical study was performed to assess the pharmacokinetics and safety of intravenous (i.v.) administration of colistin methanesulfonate (CMS) and azidothymidine (AZT) alone and in combination. Seven healthy subjects received three (every 12 h) 1-h i.v. infusions of 4, 2 and 2 million international units (MIU) of CMS co-administered with 200, 100 and 100 mg of AZT, respectively. In an ex vivo study, urinary bactericidal titres (UBTs) and time-kill curve determinations were performed in artificial urine spiked with colistin sulfate and AZT according to median and minimum peak concentrations in urine measured after the first and third dose using four mcr-1-positive colistin-resistant and five colistin-susceptible Gram-negative isolates. Reciprocal UBTs for the different colistin concentrations obtained in urine ranged from 1-128 and 0-2 for colistin-susceptible and colistin-resistant isolates, respectively. Combination with AZT could increase UBTs up to two dilution steps each for the Enterobacteriaceae and Acinetobacter strains tested. In contrast, the combination had no activity against Pseudomonas strains. In time-kill curves, the combination showed bactericidal activity against colistin-resistant strains even when the substances alone were not bactericidal. Thus, combination of CMS with AZT shows promising synergistic activity against Gram-negative uropathogens, including colistin-resistant Enterobacteriaceae. According to the urinary bactericidal activity, a maintenance dosage of 2 MIU of CMS combined with 100 mg of AZT twice daily may be sufficient for the treatment of urinary tract infections (UTIs) caused by colistin-susceptible strains. However, the dosage requires optimisation for efficient treatment of UTIs caused by colistin-resistant strains.

Synthesis and in vitro Biological Evaluation of Novel Thymidine Analogs Containing 1H-1,2,3-Triazolyl, 1H-Tetrazolyl, and 2H-Tetrazolyl Fragments

3′-Azidothymidine (AZT) reacts with 1-propargyl-5-R-1H- and 2-propargyl-5-R-2H-tetrazoles (R = H, Me, CH2COOEt, CH2CON(CH3)2, Ph, 2-CH3-C6H4, or 4-NO2-C6H4) via the Cu(I)-catalyzed asymmetric [3 + 2] cycloaddition to give 3′-modified thymidine analogs incorporating 1H-1,2,3-triazolyl, 1H-, and 2H-tetrazolyl fragments in 41–76% yield. The structures of the obtained compounds have been elucidated by means of HRESI+-MS, 1H and 13C{1H} NMR, and single crystal X-ray diffraction {for 3′-[4-(1H-5-N,N-dimethylaminocarbonylmethyltetrazol-1-yl)-1H-1,2,3-triazol-1-yl]thymidine 10d}. In vitro biological evaluation of the prepared compounds has been performed; they have exhibited low activity against phenotypic HIV-1899A. Moderate anti-influenza activity against influenza virus A/Puerto Rico/8/34 (H1N1) strain has been observed in the cases of 3′-(4-(1H-tetrazol-1-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 10a (IC50 39.6 μg/mL), 3′-(4-(2H-5-ethoxycarbonyltetrazol-2-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 11c (IC50 31.6 μg/mL), and 3′-(4-(2H-5-(4-nitrophenyl)-tetrazol-2-ylmethyl)-1H-1,2,3-triazol-1-yl)thymidine 11g (IC50 46.4 μg/mL). The tested compounds possess very low cytotoxicity towards MDCK and MT4 cells as well as tumor human cervical carcinoma HeLa and promyelocytic leukemia HL-60 cells.

A non-natural nucleotide uses a specific pocket to selectively inhibit telomerase activity.

Telomerase, a unique reverse transcriptase that specifically extends the ends of linear chromosomes, is up-regulated in the vast majority of cancer cells. Here, we show that an indole nucleotide analog, 5-methylcarboxyl-indolyl-2′-deoxyriboside 5′-triphosphate (5-MeCITP), functions as an inhibitor of telomerase activity. The crystal structure of 5-MeCITP bound to the Tribolium castaneum telomerase reverse transcriptase reveals an atypical interaction, in which the nucleobase is flipped in the active site. In this orientation, the methoxy group of 5-MeCITP extends out of the canonical active site to interact with a telomerase-specific hydrophobic pocket formed by motifs 1 and 2 in the fingers domain and T-motif in the RNA-binding domain of the telomerase reverse transcriptase. In vitro data show that 5-MeCITP inhibits telomerase with a similar potency as the clinically administered nucleoside analog reverse transcriptase inhibitor azidothymidine (AZT). In addition, cell-based studies show that treatment with the cell-permeable nucleoside counterpart of 5-MeCITP leads to telomere shortening in telomerase-positive cancer cells, while resulting in significantly lower cytotoxic effects in telomerase-negative cell lines when compared with AZT treatment.

A Remarkable Birthday Gift.

* Abbreviations: AZT — : azidothymidine HAART — : highly active antiretroviral therapy Can you recall the most remarkable birthday gift you ever received? On a recent birthday, I took note of an e-mail message from the current director of the Program for Children With AIDS, which I headed at the dawn of my career amid the agonizing depths of the HIV epidemic, which exacted a particularly devastating toll on young children and families in the 1980s and 1990s. At the time, there appeared no way to stem the tide of new perinatal and blood-borne infections. The e-mail from the director said, “We are phasing out the program since the remaining patients have transitioned to adult care. We are planning a celebration dinner and wondering if you would be willing to speak about your experience here. I really hope that you can.” Overcome with emotion, I pondered the uniqueness of this request. Medical centers host galas to hail program openings, but how exceptional to fete a closing! Having spoken at innumerable celebrations, I could think of none more worthy of profound commemoration, yet how does one find words? At that moment, an old, familiar theme of that earlier era echoed back to mind. The blockbuster Broadway musical Rent portrays 1 year in the lives of friends in New York City who face poverty, eviction, and HIV infection at a time when azidothymidine (AZT) was the only treatment. In the hit song “Seasons of Love,” the cast confronts the age-old question, “How do we measure a year in the life?” According to the lyrics, 1 answer is, “Five hundred twenty-five thousand six hundred minutes.” By that accounting, >19 447 200 minutes have passed … Address correspondence to Joseph S. Cervia, MD, MBA, FACP, FAAP, FIDSA, AAHIVS, Departments of Medicine and Pediatrics, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 400 Community Dr, Manhasset, NY 11030. E-mail: jcervia{at}northwell.edu

Cardiovascular risk factors among people living with HIV in rural Kenya: a clinic-based study.

To determine the prevalence of cardiovascular risk factors and their association with antiretroviral therapy (ART) among HIV-infected adults in a rural sub-county hospital in Kenya. This was a descriptive survey of patient charts characterising cardiovascular risk among adult patients (> 18 years) at Ukwala sub-county hospital between June 2013 and January 2015. Post-stratification survey weights were applied to obtain prevalence levels. Adjusted odds ratios (AOR) for each variable related to cardiovascular risk factors were calculated using logistic regression models. Overall, the prevalence of diabetes mellitus was 0.4%, 0.3% of patients had had a previous cardiovascular event (heart attack or stroke), 40.4% had pre-hypertension, while 10.4% had stage 1 and 2.9% stage 2 hypertension. Up to 14% of patients had elevated non-fasting total cholesterol levels. Factors associated with hypertension were male gender (AOR 1.59, p = 0.0001), being over 40 years of age (AOR 1.78, p = 0.0001) and having an increased waist circumference (OR 2.56, p = 0.0014). Raised total cholesterol was more likely in those on tenofovir disoproxil fumarate (TDF) (AOR 2.2, p = 0.0042), azidothymidine (AZT) (AOR 2.5, p = 0.0004) and stavudine (D4T) -containing regimens (AOR 3.13, p = 0.0002). An elevated prevalence of undiagnosed cardiovascular risk factors such as hypertension and raised total cholesterol levels was found among people living with HIV. There was an association between raised total cholesterol and nucleoside reverse-transcriptase inhibitor (NRTI) -based ART regimens. Our findings provide further rationale for integrating routine cardiovascular risk-factor screening into HIV-care services.

Joint treatment with azidothymidine and antiserum for eradication of avian leukosis virus subgroup a contamination in vaccine virus seeds.

Contamination of avian attenuated vaccines by avian leukosis virus (ALV) is considered to be a specific horizontal transmission of ALV. Eradication of ALV contamination in vaccine virus seeds is thus a precondition of qualified vaccine production. In this study, we used the nucleoside reverse transcriptase (RT) inhibitor azidothymidine (AZT) together with monofactor antiserum against avian leukosis virus subgroup A (ALV-A) to remove ALV-A from vaccine virus seeds. Different doses of ALV-A were artificially added to the Newcastle disease virus (NDV) vaccine seeds, then the ALV-contaminated attenuated virus vaccine virus seeds were cultured in DF-1 cells. Single-drug treatment with 5μg/mL AZT or 5% (v/v) as well as combined treatment with AZT and antiserum significantly suppressed ALV-A replication (P < 0.001) in the vaccine virus seeds. Complete absence of virus replication was observed in cells exposed to joint treatment with AZT and antiserum. The treated virus seeds met the requirements of the Chinese Ministry of Agriculture. Therefore, combined treatment with AZT and antiserum can be used to eradicate contaminating ALV-A from vaccine virus seeds, thus providing a new approach for improving vaccine safety.

Nucleoside reverse transcriptase inhibitor backbones and pregnancy outcomes.

The aim of this study was to investigate whether specific nucleoside reverse transcriptase inhibitor (NRTI) backbones are associated with risk of adverse pregnancy outcomes among pregnant women starting antiretroviral therapy (ART). Seven observational studies across eight European countries of pregnancies in HIV-positive women. Individual-level data were pooled on singleton pregnancies conceived off-ART in which a single combination ART regimen was initiated at least 2 weeks before delivery, and ending in a live birth in 2008-2014. Preterm delivery (PTD) was defined as less than 37 gestational weeks and small-for-gestational-age (SGA) as less than 10th percentile according to INTERGROWTH standards. Poisson regression models were fitted to investigate associations between NRTI backbones and PTD/SGA. Out of 7193 pregnancies, 45% (3207) were in UK/Ireland, 44% (3134) in Ukraine. 10% (722/7193) of deliveries were preterm and 11.1% (785/7089) of newborns SGA. The most common NRTI backbones were zidovudine (ZDV)-lamivudine (3TC) (71%), tenofovir (TDF)-XTC (16%) and abacavir (ABC)-3TC (10%) with TDF-containing backbone use increasing over time. Overall, 77% of regimens contained ritonavir-boosted lopinavir (LPV/r). There was no association between NRTI backbone and PTD in main adjusted analyses [adjusted prevalence ratios (aPRs) 0.97 (95% confidence interval, 95% CI 0.73-1.28] for ABC-3TC and aPR 1.06 (95% CI 0.83-1.35) for TDF-XTC, both vs. ZDV-3TC) or in 4720 pregnancies on LPV/r [aPR 1.03 (95% CI 0.74-1.43) for ABC-3TC and aPR 1.16 [0.85-1.57] for TDF-XTC, both vs. ZDV-3TC]. Infants exposed to ABC-3TC or TDF-XTC in utero were less likely to be SGA than those exposed to ZDV-3TC [aPR 0.72 (95% CI 0.53-0.97) and aPR 0.70 (95% CI 0.53-0.93), respectively]. Results support the safety of TDF-XTC backbones initiated in pregnancy with respect to gestation length and birthweight.

Treatment effects of the differential first-line antiretroviral regimens among HIV/HBV coinfected patients in southwest China: an observational study

HIV with HBV co-infection can result in greater HIV-related immunosuppression, morbidity and mortality. Currently, there are few studies to evaluate direct treatment effects on mortality and attrition rates between first-line antiretroviral therapy (ART) based-on tenofovir (TDF) and/or lamivudine (3TC) in a real-world setting. We used Cox proportional hazard models to evaluate direct treatment effects of the first-line ART containing stavudine (d4T), azidothymidine (AZT) and TDF on death and attrition among HIV patients with HBV coinfection. A total of 3912 patients met study eligibility criteria. The overall mortality rate and attrition rate was 2.85 (95% CI: 2.55–3.16) and 8.87 (95% CI: 8.32–9.41) per 100 person-years, respectively. The ART containing TDF had a significantly lower risk of death [adjusted hazard ratio (AHR) = 0.58, 95% CI: 0.44–0.77] when compared to the ART containing d4T, but the risk of death was not significantly different when compared to the ART containing AZT (AHR = 0.91, 95% CI: 0.69–1.20). Patients with HIV/HBV coinfection receiving the ART containing TDF had significantly lower risk rates of attrition compared to those receiving the ART containing d4T (AHR = 0.72, 95% CI: 0.60–0.86) or AZT (AHR = 0.67, 95% CI: 0.58–0.77). Compared with the ART containing d4T, the ART containing AZT was significant and not significant associated with a lower risk of death and attrition, respectively. The ART containing TDF had significant effects on both of death and attrition among HIV patients with HBV coinfection.

Colistin-Azidothymidine Synergy Against Enterobacteriaceae

Literature from 30 years ago showed activity of the antiretroviral drug azidothymidine (AZT), used in the treatment of HIV, against Escherichia coli

PHOTOCATALYTIC DEGRADATION OF PHARMACEUTICAL DRUG ZIDOVUDINE BY UNDOPED AND 5 % BARIUM DOPED ZINC OXIDE NANOPARTICLES DURING WATER TREATMENT: SYNTHESIS AND CHARACTERISATION

Objective: To study the photocatalytic degradation of pharmaceutical drug zidovudine (ZDV) by synthesized undoped zinc oxide nanoparticles (ZONPs) and 5% (mole ratio) barium doped zinc oxide nanoparticles (BZONPs) during water treatment.Methods: Kinetics studies were carried out with the help of UV-Visible Spectrophotometer. High-Resolution Mass Spectrophotometry (HR-MS) was used to identify products. A photo-reactor with mercury lamp was used as an external source of light energy. Optical power meter was used for the measurement of light intensity. The particle size of the synthesized photocatalysts was identified with the help of siemens x-ray diffractometer (XRD). The surface topography of photocatalysts was done by scanning electron microscope (SEM). Transmission electron microscopy (TEM) was used for the studies of particle size and morphology.Results: Five degraded products of ZDV are identified by HR-MS. A suitable electron-hole pair mechanism is projected. XRD patterns show that the intensity of peak is slightly stronger in ZONPs. There is an increase in the rate of photocatalytic degradation of ZDV by adding different quantities of photocatalyst from 0.05 g l-1 to 0.1 g l-1. The kinetic data reveals that there is an initial increase in the values of rate constants with the increase in the concentration of ZDV. The kinetic data indicate that the values of rate constants are higher at pH = 9. There is an increase in the rate constant values with an increase in the light intensities of UV lamp.Conclusion: The rates of photocatalytic degradation of ZDV were found to be higher using 5 % (mole ratio) BZONPs as a photocatalyst.

Stability behaviour of antiretroviral drugs and their combinations. 9: Identification of incompatible excipients

Incompatibility studies of antiretroviral drugs, viz., lamivudine (3TC), emtricitabine (FTC), abacavir sulfate (ABC), tenofovir disoproxil fumarate (TDF), zidovudine (ZDV), efavirenz (EFV) and nevirapine (NVP) were carried out in the presence of ten selected excipients, i.e., microcrystalline cellulose, lactose monohydrate, starch, magnesium stearate, sodium lauryl sulfate, sodium starch glycolate, croscarmellose sodium, colloidal silica, povidone K-30 and hydroxypropyl cellulose. Among all, ABC showed reaction with lactose monohydrate, resulting in the formation of two interaction products, while sodium lauryl sulphate enhanced the degradation of TDF. The interaction products of ABC-Lactose were separated by high performance liquid chromatography (HPLC) and subjected to liquid chromatography-high resolution mass spectrometry (LC-HRMS) studies for their characterization. One of the products was also isolated and subjected to 1D and 2D nuclear magnetic resonance (NMR) studies for structural confirmation. The toxicity of both was predicted using TOPKAT and ADMET™ software and compared to the drug.

ANALYSIS OF ADVERSE DRUG REACTION REPORT FORMS ON THE MEDICINES, USED FOR AIDS TREATMENT (REGISTERED IN THE REPUBLIC OF CRIMEA IN THE PERIOD FROM 2011 TO 2016)

According to the data of the World Health Organization (WHO), human immunodeficiency virus (HIV) remains a major global public health problem.The mainmethod of treating HIV is using highly active antiretroviral therapy (HAART), which is the use of multiple medicines acting on different viral targets. The timely onset of HAART can suppress the replication of the virus in the human body and helps to strengthen its immune system and restore its ability to fight infections. At the same time, the choice of medicines to improve the quality of life and patients’ compliance during antiretroviral therapy should be based on their effectiveness and safety. The aim of this research was to analyze and study the adverse reactions that occur in patients with HIV living in the territory of the Republic of Crimea, when using HAART.Materials and methods.The objects of research were 274 report cards about the adverse reactions, registered in the regional base (registry) of spontaneous messages called ARCADe (Adverse Reactions in Crimea, Autonomic Database) for the period from 2011 to 2016.Results.The results of the study showed that the most often adverse reactions were observed when using medicines of the group of Nucleoside Reverse Transcriptase Inhibitors (NRTI). This is explained by the inclusion of NRTI medicines as the main medicine in the method of HAART. Efavirenz (EFV) and Nevirapine (NVP) were absolute leaders among these groups of antiretroviral medicines. Among the combined antiviral medicines active against HIV, the most frequently adverse reactions were associated with the use of a combination of Lamivudine (3TC) and Zidovudine (ZDV). The main clinical manifestations of adverse reactions in the use of combination medicines for treating HIV were a decrease in the level of hemoglobin and the development of anemia. At the same time, in 85% of cases, the patients needed medication in order to correct the resulting adverse drug reaction (ADR). The combination of antiretroviral therapy has often been associated with the development of serious ADR. In case of monotherapy, the main clinical manifestations of adverse reactions were disorders of the central nervous system (dizziness, hallucinations, sleep disorders) and allergic reactions of varying severity (including 1 case of angioedema to “Eferven” (Efavirenz (EFV)),600 mg). Hereby, in almost half of the cases, the usage of antiretroviral medicines of the NRTI group and protease inhibitors caused the development of serious side effects. This confirms the necessity to study and analyze adverse reactions in order to increase the safety of patients’ pharmacotherapy and improve their quality of life.Conclusion.The study of adverse reactions to the medicines used for treatment of HIV is of a paramount importance in improving the safety and compliance of HIV patients to lifelong pharmacotherapy.

Synthesis and in vitro anticancer activity of N-alkyl phosphoramidate monoesters of 3’-azido-3’-deoxythymidine (AZT)

Synthesis and in vitro anticancer activity of N-alkyl phosphoramidate monoesters of 3’-azido-3’-deoxythymidine (AZT)

Intrinsic Replication Competences of HIV Strains After Zidovudine/Lamivudine/Nevirapine Treatment in the Philippines.

Although drug-resistant HIV variants are considered to be less fit than drug-susceptible viruses, replication competence of these variants harbored by patients has not yet been elucidated in detail. We herein assessed the replication competence of strains obtained from individuals receiving antiretroviral therapy. Among 11 306 participants in a drug resistance surveillance in the Philippines, 2629 plasma samples were obtained from individuals after a 12-month treatment with zidovudine (ZDV)/lamivudine (3TC)/nevirapine (NVP). The replication competence of HIV isolates was then assessed by reinoculation into seronegative peripheral blood mononuclear cells in the absence of drugs in vitro. The drug resistance rate was estimated to be 9.2%. Drug-resistant strains were still a minority of closely related strains in a phylogenetic cluster. Among the available 295 samples, 37 HIV strains were successfully isolated. Progeny viruses were produced at a wide range (5.1 × 106 to 3.4 × 109 copies/mL) in primary culture of peripheral blood mononuclear cells. The viral yields were higher than the corresponding plasma viral load (1300 to 3.4 × 106 copies/mL) but correlated with those (r = 0.4). These results suggest that strains with higher intrinsic replication competence are one of the primary targets of newly selected drugs at the increasing phase of the plasma viral load during antiretroviral therapy.

AZT sensitizes hepatocellular carcinoma cells to As 2 O 3 by upregulating the arsenic transporter aquaglyceroporin 9

Background: Even though the mechanism is unknown, previous studies have demonstrated that the traditional chemotherapy agents, 3'-azido-3'-deoxythymidine (AZT) and arsenic trioxide (As 2 O 3 ), can synergetically inhibit the growth, migration and the invasion of hepatocellular carcinoma cells. This study aimed to investigate the role which aquaglyceroporin 9 (AQP9), an arsenic channel protein which is widely distributed in the liver tissues, plays in the process of As 2 O 3 combined with AZT in inhibiting growth, migration and the invasion of hepatocellular carcinoma cells. Methods: HepG2 and MHCC97H cells were treated using As 2 O 3 (2 µM) combined with a wide range of different concentrations of AZT (0, 10, 20 µM) for 48 h, and the proliferation inhibition rates were detected using a MTT assay. AQP9 mRNA/protein expression was determined by RT-PCR and western blotting assays, respectively. Next, HepG2 cells were electro-transfected with AQP9 siRNA to disturb the expression of AQP9, which was verified by RT-PCR and western blotting. The effect of the 2 µM As 2 O 3 combined with 20 µM AZT (the optimum synergy inhibition concentration investigated previous) on the migration and invasion of HepG2 cells was then measured by wound healing assay and transwell migration assay and invasion assays, respectively, before and after an AQP9-siRNA transfection. Results: The proliferation inhibition rate from the combination of As 2 O 3 and AZT on the hepatocellular carcinoma cells was significantly higher than the rate from As 2 O 3 alone (P<0.05), and it had a greater dose-dependent effect when it was compared to AZT. A low dose of As 2 O 3 (2 µM) combined with AZT (20 µM) also significantly inhibited the migration and invasion of liver cell carcinoma. The expression levels of AQP9 in the combination of As 2 O 3 (2 µM) and AZT (20 µM) group were significantly higher than those from the As 2 O 3 alone group and the blank control group (P<0.05). After silencing AQP9, the effect of the combination between As 2 O 3 and AZT for the migration and invasion of liver cell carcinoma was significantly reduced (P<0.05). Conclusions: AZT improves the efficiency of As 2 O 3 on inhibiting the proliferation, migration and invasion of hepatocellular carcinoma cells by up-regulating the expression of AQP9, which has important implications in reducing the poisonous side effect of As 2 O 3 for cancer therapies.

Topology of electron density and electrostatic potential of HIV reverse transcriptase inhibitor zidovudine from high resolution X-ray diffraction and charge density analysis

Azidothymidine (AZT) is a first anti-HIV drug namely Zidovudine used for HIV treatment, which binds to the viral DNA primer and inhibits the HIV reverse transcription. The side effects of this powerful drug are severe and the detailed understanding of its electronic structure helps to design new drugs from the AZT molecule. Present study aims to determine the structure of AZT at electronic level from the experimental charge density analysis as well as the solid state DFT calculations. AZT was crystallized and low temperature high resolution X-ray diffraction intensity data has been measured up to sin (θ/λ)max = 1.1 Å−1 at 100.0 (2) K. The crystal structure of AZT was determined, which reveals the information that the AZT compound crystallizes with two molecules in the asymmetric unit which are conformationally different and linked through strong hydrogen bonding interactions (dimer). The Hirshfeld surface of both molecules shows the locations of weak and strong interactions. Further, a multipole model refinement was carried out using Hansen-Coppens multipole formalism. The experimental topological properties of electron density of AZT molecules were determined and compared with the results of theoretical DFT calculations based on solid state and gas phase studies. The charge density distribution of the two molecules in the asymmetric unit is unequal and shows some difference. The topological properties of O–H⋅⋅⋅O, O–H⋅⋅⋅N, C–H⋅⋅⋅N, H⋅⋅⋅H and azide⋅⋅⋅azide group interactions are also determined. The electrostatic potential (ESP) surface of both AZT molecules in the crystal exhibits high electronegative regions around the O, N atoms and also around the azide group, however, ESP regions of molecules (I) and (II) are not similar.

Hepatic and renal toxicity and associated factors among HIV-infected children on antiretroviral therapy: a prospective cohort study.

The aim of the study was to investigate the prevalence of renal function and liver enzyme abnormalities among HIV-infected children, changes in prevalence with time on combination antiretroviral therapy (cART), and the factors associated with these abnormalities. A prospective cohort study was conducted among HIV-infected children < 18 years old (n = 705) who were on first-line cART. Liver enzymes, renal function, haematology, immunology and virological response were assessed at enrolment and followed bi-annually for 18 months. Liver fibrosis and cirrhosis were assessed using noninvasive markers including the aspartate aminotransferase (AST) to platelet ratio index (APRI) and fibrosis score (FIB-4). The median age was 12 [interquartile range (IQR) 8-14] years; 53.3% of patients were male. At enrolment, the median cART duration was 3.3 (IQR 1.1-6.1) years; 177 (25.1%) and 83 (11.8%) patients had elevated AST and alanine aminotransferase (ALT), respectively. A tenth of the children had an APRI score > 0.5, suggesting liver fibrosis. Being on a zidovudine (ZDV)- or nevirapine (NVP)-based regimen and having a viral load > 1000 HIV-1 RNA copies/mL were significantly associated with elevated ALT. Twenty-four (3.4%) and 84 (12.1%) patients had elevated creatinine and blood urea nitrogen (BUN), respectively. As cART duration increased by 6 months, median BUN increased by 1.6 [95% confidence interval (CI) 0.4-2.7] mg/dL (P = 0.01); the glomerular filtration rate (GFR) decreased by 35.6 (95% CI 17.7-53.4) mL/min/1.73 m2 (P < 0.0001); and AST and ALT decreased by 1.4 (95% CI 0.4-2.5) IU/L (P = 0.01) and 1.4 (95% CI 0.2-2.6) IU/L (P = 0.01), respectively. A high prevalence of liver enzyme and renal function abnormalities was observed at enrolment. Decreasing liver enzyme levels during follow-up are possibly reassuring, while the progressive reduction in GFR and the increase in BUN are worrisome and require further study.

Revitalizing the AZT Through of the Selenium: An Approach in Human Triple Negative Breast Cancer Cell Line.

Triple-negative breast cancer represents about 15% of all cases of breast cancer, and still represents a therapeutic challenge. 3′-Azido-3′-deoxythymidine (AZT) is a nucleoside reverse transcriptase inhibitor with antitumor activity. Chalcogenides compounds, such as selenium, are very important intermediates applied in organic synthesis. Our objective was to investigate the effect and the underlying cell death mechanisms of AZT and its derivatives, in human breast cancer cell lines. The inhibitory effect of AZT and derivatives (1072, 1073, and 1079) was determined by MTT assay (0.1, 1, 10, 50, and 100 μM for concentrations and times 4, 24, 48, and 72 h) and Live/Dead in tumor cell lines MCF-7, MDA-MB 231 and also in non-tumor cell line CHO. Gene expression profiles related to apoptosis were investigated by qRT-PCR and induction of apoptosis was investigated by flow cytometry. MTT and Live/Dead assays showed that AZT derivatives decreased the rate of cell proliferation at concentrations of 50 and 100 μM in tumor cell lines MCF-7 and MDA-MB 231 while the commercial AZT presented a low antitumoral potential in all strains tested. In flow cytometry analysis we demonstrated that derivatives of AZT induced apoptosis, with an increase in both initial and late stages in both tumor cell lines evaluated, especially in MDA-MB 231. Our data show that the AZT derivative 1072 increased the expression of transcripts of the genes caspase 3 and 8 in MDA-MB 231 cell line when compared to control, suggesting that the extrinsic pathway of apoptosis was activated. In conclusion, derivatives of AZT, especially 1072, induce cytotoxicity in vitro in the triple negative breast cancer cell line through activation of the extrinsic pathway of apoptosis. These compounds containing selenium in its formulation are potential therapeutic agents for breast cancer.