NAT2 Genotype Research Articles

NAT1 genetic variation increases asthma risk in children with secondhand smoke exposure

Objective We previously reported that children exposed to secondhand smoke (SHS) that carried variants in the NAT1 gene had over two-fold higher hair cotinine levels. Our objective was to determine if NAT1 polymorphisms confer increased risk for developing asthma in children exposed to SHS. Methods White participants in the Cincinnati Childhood Allergy and Air Pollution Study (n = 359) were genotyped for 10 NAT1 variants. Smoke exposure was defined by hair cotinine and parental report. Asthma was objectively assessed by spirometry and methacholine challenge. Findings were replicated in the Genomic Control Cohort (n = 638). Results Significant associations between 5 NAT1 variants and asthma were observed in the CCAAPS exposed group compared to none in the unexposed group. There was a significant interaction between NAT1 rs13253389 and rs4921581 with smoke exposure (p = 0.02, p = 0.01) and hair cotinine level (p = 0.048, p = 0.042). Children wildtype for rs4921581 had increasing asthma risk with increasing hair cotinine level, whereas those carrying the NAT1 minor allele had an increased risk of asthma regardless of cotinine level. In the GCC, 13 NAT1 variants were associated with asthma in the smoke-exposed group, compared to 0 in the unexposed group, demonstrating gene-level replication. Conclusions Variation in the NAT1 gene modifies asthma risk in children exposed to secondhand-smoke. To our knowledge, this is the first report of a gene-environment interaction between NAT1 variants, smoke exposure, cotinine levels, and pediatric asthma. NAT1 genotype may have clinical utility as a biomarker of increased asthma risk in children exposed to smoke.

NAT2 slow acetylator is associated with anti-tuberculosis drug-induced liver injury severity in indonesian population.

Aim: We investigated the contribution of NAT2variants and acetylator status to anti-tuberculosis drug-induced liver injury (AT-DILI) severity. Materials & methods: 100patients with clinically severe AT-DILI and 210 non-AT-DILI controls were subjected to NAT2 genotyping by direct DNA sequencing. Results: NAT2 slow acetylator was significantly associated with AT-DILI risk (p = 2.7×10-7; odds ratio [95% CI] =3.64 [2.21-6.00]). Subgroup analysis of NAT2 ultra-slow acetylator revealed a stronger association with AT-DILI risk (p = 4.3×10-6; odds ratio [95% CI] =3.37 [2.00-5.68]). Subset analysis of NAT2 acetylator status and severity grade confirmed these results in AT-DILI patients with more severe disease whereas fast and intermediate acetylator phenotypes were associated with a decreased AT-DILI risk. Conclusion: We elucidated the role of NAT2 phenotypes in AT-DILI in Indonesian population, suggesting that NAT2 genotype and phenotype determination are important to reduce AT-DILI risk.

Anthropometric and Genetic Factors Associated With the Exposure of Rifampicin and Isoniazid in Mexican Patients With Tuberculosis.

Tuberculosis (TB) remains a critical infectious, contagious disease worldwide with high prevalence and mortality rate. The directly observed treatment short-course therapy includes rifampicin (RMP) and isoniazid (INH) for at least 6 months. The purposes of this scheme are to interrupt the transmissibility of the Mycobacterium tuberculosis complex and to avoid secondary complications. Low plasma concentrations of these anti-TB drugs have been associated with extended treatment duration, therapeutic failure, and relapse. The determination of anthropometric, genetic, and clinical variables that may affect plasma concentrations of RMP and INH might facilitate the detection of patients at increased risk of therapeutic failure. A prospective observational study was performed in patients with TB diagnosis. A fixed-dose combined formulation was administered following clinical guidelines, and 12 venous blood samples were collected within 24 hours after dose for the quantification of plasma levels of RMP and INH by high-performance liquid chromatography-ultraviolet. The plasma concentrations versus time for each drug in each patient were assessed by a noncompartmental approach to obtain Cmax, and the area under the concentration-time curve to the last observation point (AUC0-24 h) was calculated by the linear trapezoidal rule. Genetic polymorphisms of the enzyme involved in INH metabolism (NAT2) and proteins involved in RMP transport (glycoprotein-P and OATP1B1) were determined. A total of 34 patients aged between 18 and 72 years with the diagnosis of TB were included in the current study. A multivariate analysis was performed to determine the anthropometric and genetic characteristics that modified the Cmax and AUC0-24 h of RMP and INH. Results indicated that RMP Cmax and AUC0-24 h were affected by sex, dose/weight, and single nucleotide polymorphism of MDR1. In addition, age, body mass index, and NAT2 acetylator genotype were shown to determine the Cmax and AUC0-24 h for INH. Anthropometric, genetic, and dosage characteristics of Mexican patients with TB are an important source of risk for subtherapeutic plasma concentrations of anti-TB drugs. Factors such as lower-than-recommended RMP dose, male patients with TB, and MDR1 3435 genotype, in addition to age group, body mass index, and INH acetylator phenotype based on NAT2 genotype, should be considered during treatment.

Isoniazid Concentration and NAT2 Genotype Predict Risk of Systemic Drug Reactions during 3HP for LTBI

Weekly rifapentine and isoniazid therapy (known as 3HP) for latent tuberculosis infection (LTBI) is increasingly used, but systemic drug reactions (SDR) remain a major concern. Methods: We prospectively recruited two LTBI cohorts who received the 3HP regimen. In the single-nucleotide polymorphism (SNP) cohort, we collected clinical information of SDRs and examined the NAT2, CYP2E1, and AADAC SNPs. In the pharmacokinetic (PK) cohort, we measured plasma drug and metabolite levels at 6 and 24 h after 3HP administration. The generalised estimating equation model was used to identify the factors associated with SDRs. Candidate SNPs predicting SDRs were validated in the PK cohort. A total of 177 participants were recruited into the SNP cohort and 129 into the PK cohort, with 14 (8%) and 13 (10%) in these two cohorts developing SDRs, respectively. In the SNP cohort, NAT2 rs1041983 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 7.00 [2.03–24.1]) and CYP2E1 rs2070673 (AA vs. TT+TA, OR [95% CI]: 3.50 [1.02–12.0]) were associated with SDR development. In the PK cohort, isoniazid level 24 h after 3HP administration (OR [95% CI]: 1.61 [1.15–2.25]) was associated with SDRs. Additionally, the association between the NAT2 SNP and SDRs was validated in the PK cohort (rs1041983 TT vs. CC+CT, OR [95% CI]: 4.43 [1.30–15.1]). Conclusions: Isoniazid played a role in the development of 3HP-related SDRs. This could provide insight for further design of a more optimal regimen for latent TB infection.

Mucosal 5-aminosalicylic acid concentration, drug formulation and mucosal microbiome in patients with quiescent ulcerative colitis.

SummaryBackground5‐aminosalicylic acid (5‐ASA) is the first‐line therapy for ulcerative colitis (UC). 5‐ASA acts locally in the colonic mucosa by numerous proposed mechanisms, and is metabolised by N‐acetyltransferase (NAT). Large variations in mucosal 5‐ASA concentrations have been reported, but the underlying mechanisms are not understood.AimTo study the relationship between 5‐ASA concentration, 5‐ASA formulation, NAT genotype and bacterial microbiome in patients with UC.MethodsPatients with quiescent UC, using monotherapy of Mezavant (n = 18), Asacol (n = 14) or Pentasa (n = 10), 4.0‐4.8 g/day were included. 5‐ASA was measured in colonic mucosal biopsies and serum by ultra‐high performance liquid chromatography. NAT genotypes were determined by Sanger sequencing. Bacterial microbiome was sequenced from faeces and mucosa by 16S rRNA sequencing using Illumina Miseq.ResultsMezavant provided the highest mucosal 5‐ASA levels (geometric mean 2.39 ng/mg), followed by Asacol (1.60 ng/mg, 33% lower, P = 0.50) and Pentasa (0.57 ng/mg, 76% lower, P = 0.033). Mucosal 5‐ASA concentration was not associated with NAT genotype, but serum 5‐ASA concentration and NAT1 genotype was associated (P = 0.044). Mucosal 5‐ASA concentration was positively associated with mucosal bacterial diversity (P = 0.0005) and bacterial composition. High mucosal 5‐ASA concentration was related to reduced abundance of pathogenic bacteria such as Proteobacteria, and increased abundance of several favourable bacteria such as Faecalibacterium.ConclusionsMucosal 5‐ASA concentration is positively associated with bacterial diversity and a mucosal bacterial composition that are perceived favourable in UC. Mezavant yielded higher mucosal 5‐ASA concentrations than Pentasa. 5‐ASA may have beneficial effects on the mucosal microbiome, and high concentrations possibly amend dysbiosis in UC.

Effects of genetic variability on rifampicin and isoniazid pharmacokinetics in South African patients with recurrent tuberculosis.

We report the prevalence and effect of genetic variability on pharmacokinetic parameters of isoniazid and rifampicin. Genotypes for SLCO1B1, NAT2, PXR, ABCB1and UGT1A genes were determined using a TaqMan® Genotyping OpenArray™. Nonlinear mixed-effects models were used to describe drug pharmacokinetics. Among 172 patients, 18, 43 and 34% were classified as rapid, intermediate and slow NAT2 acetylators, respectively. Of the 58 patients contributing drug concentrations, rapid and intermediate acetylators had 2.3- and 1.6-times faster isoniazid clearance than slow acetylators. No association was observed between rifampicin pharmacokinetics and SLCO1B1, ABCB1, UGT1Aor PXR genotypes. Clinical relevance of the effects of genetic variation on isoniazid concentrations and low first-line tuberculosis drug exposures observed require further investigation.

N-acetylation capacity of N-acetyltransferase 2 in human peripheral blood mononuclear cells regulated by NAT2 genotype and sirtuin 1

N-acetylation capacity of N-acetyltransferase 2 in human peripheral blood mononuclear cells regulated by NAT2 genotype and sirtuin 1

Study of the xenobiotics detoxication system in patients with stone kidney disease

The aim of the study was to evaluate the distribution of the variant alleles and genotypes of the polymorphic loci of the xenobiotics biotransformation system gene NAT2 in patients with urolithiasis (SKD) and to determine the nature of their polymorphism in the healthy population. 60 patients aged 20–65, with SKD who were treated in the urological department of the Ivano-Frankivsk central city hospital in 2016–2018 were examined. The control group comprised healthy individuals of the same age, selected by random sampling, living in different regions of Ivano-Frankivsk oblast (157 people). The material for the study was a DNA isolated from leukocytes in the peripheral blood of patients. In subsequent phases of the study, amplification of DNA sequences in vitro was performed using the polymerase chain reaction method. The analysis of the frequency of NAT2 genotypes combinations in patients with SKD showed that homozygous mutant deletion of 481CC was more common in patients than in healthy subjects. Comparison of allelic frequencies and 481TC genotypes in patients revealed that the heteronucleases were 77.8% versus 41.0% in healthy subjects, with a significant difference (PN <0.05). Under such conditions, it can be assumed that the presence of a homozygous mutant deletion of the CC locus of the T481C and the GG of the A803G locus of the NAT2 gene, with high probability, suggests an adverse, recurrent CKD. The heterozygous version of the TC of the locus T481C determines partial control of the ailment. The heterozygous variant of the AG locus A803G determines the increased susceptibility to the disease, without clearly affecting its phenotypic variant. In this case, the homozygous variant of the AA allele of the A803G locus, the homozygous TT, and the heterozygous TC deletion of the T481C allele are protectors for the development of SKD.

Occupational exposures and genetic susceptibility to urinary tract cancers: a systematic review and meta-analysis.

This study aims to summarize the current knowledge on the relationship between genetic polymorphisms, occupational exposures, and urinary tract cancers. We searched MEDLINE, ISI Web of science, and SCOPUS online databases for all articles published in English language up to September 2016. A meta-analysis was performed to provide summary estimates for the association between a certain genetic polymorphism, occupational exposure and bladder cancer (BC) or kidney cancer (KC), when appropriate. Fifteen studies on BC and six on KC were deemed eligible for the review. With regard to BC, an overall odds ratio (OR) of 2.07 [95% confidence interval (CI): 1.38-3.09] for those with GSTM1 and an OR of 2.07 (95% CI: 1.38-3.09) for those with GSTT1 null genotype were reported when exposed to polycyclic aromatic hydrocarbons (PAHs). NAT2 slow genotype carriers had an OR of 3.59 (95% CI: 2.62-4.93) for BC when exposed to aromatic amines and an OR of 2.07 (95% CI: 1.36-3.15) when exposed to PAHs. With regard to KC and pesticide exposure, the meta-analysis reported an OR of 4.38 (95% CI: 2.28-8.41) for GSTM1 present genotype, an OR of 2.59 (95% CI: 1.62-4.15) for GSTT1-present genotype and an OR of 6.51 (95% CI: 2.85-14.89) for combined effects of GSTM1 and GSTT1 active genotypes. This meta-analysis indicates a possible association between the variant genotypes of GSTM1, GSTT1, NAT2 and SULT1A1, occupational exposure to aromatic amines or PAHs, and development of BC. Our results suggest that polymorphisms in GSTM1 and GSTT1 genes could influence the risk for developing KC in individuals occupationally exposed to pesticides.

NAT2 ultra-slow acetylator and risk of anti-tuberculosis drug-induced liver injury: a genotype-based meta-analysis.

NAT2 slow acetylator is a confirmed risk of anti-tuberculosis drug-induced liver injury (ATDILI). However, NAT2 ultra-slow acetylators, a new refinement among NAT2 slow acetylators, have been recently proposed. The patients with NAT2 genotypes of *6A/*6A, *6A/*7B and *7B/*7B are referred to in this group. We aim to prove an association of the NAT2 ultra-slow acetylators with the risk of ATDILI. Systematic review and meta-analysis were performed based on each NAT2 genotype and risk of ATDILI cases and also new classification of the ultra-slow acetylators up to 31 October 2016. Meta-analysis of 18 studies with 822 ATDILI cases and 4630 controls was carried out in the RevMan software, version 5.3 with fixed-effect (low heterogeneity) and random effect (moderate to high heterogeneity) methods. The strong associations between each NAT2 slow acetylator genotypes and ATDILI were confirmed in meta-analysis except for NAT2*5B/*5B [odds ratio (OR): 1.69; 95% confidence interval (CI): 0.96-2.95; P=0.0679]. The NAT2 ultra-slow acetylators contribute to higher risk of ATDILI (OR: 3.60; 95% CI: 2.30-5.63; P=1.76E-08) than all NAT2 slow acetylators (OR: 2.80; 95% CI: 2.20-3.57; P=5.73E-18) as well as fast acetylators. Additional in-vitro study using isoniazid as a substrate supports the existence of ultra-slow acetylator alleles (NAT2*6A and NAT2*7B). This is the first meta-analysis of NAT2 and the risk of ATDILI at the genotypic level. The result demonstrated that NAT2 ultra-slow acetylator genotypes will have the most effect on the increased risk of ATDILI.

Polymorphisms of NAT2, CYP2E1, GST, and HLA related to drug-induced liver injury in indonesian tuberculosis patients.

Gene polymorphisms have been associated with drug-induced liver injury (DILI). This study aimed to elucidate the association between polymorphisms of NAT2, CYP2E1, GSTT1, GSTM1, and HLA genes with isoniazid plasma concentration and DILI. This study was a prospective cohort study recruiting adult newly diagnosed tuberculosis (TB) patients who met the inclusion criteria from the Public Health Centers in Yogyakarta and Lampung. Defined single-nucleotide polymorphisms were rs1799929, rs1799930, rs1799931, rs1801280, and rs1041983 of NAT2; rs2031920, rs8192775, and rs2515641 of CYP2E1; rs1041981, rs1063355, and rs6906021 of HLA. GSTT1 and GSTM1 were defined as GSTT1, GSTM1, and GSTT1 deletion and GSTM1 deletion. The DNA was taken from the patient saliva. Data of anti-TB drug plasma concentration on the weeks 4-8 of treatment were retrieved from the patients' medical report. Statistical analysis was performed using Chi-square test, Student's t-test, and multinomial logistic regression. Over the 207 patients, up to 1.9% of them experienced DILI. The percentage of slow acetylators of NAT2 was 69.5%. Patients with extensive acetylator phenotype did not experience DILI (odds ratio [OR]: 0.46; 95% confidence interval [CI]: 0.23-0.94). The G carriership of HLA rs1063355 could protect the patients from the DILI (OR: 0.39; 95% CI: 0.14-0.9). Furthermore, the C carriership of HLA rs1041981 can protect the patients from DILI (OR: 0.38; 95% CI: 0.15-0.50). The genotype of HLA-DQB*0302 significantly affects the isoniazid concentration. The NAT2 genotype was significantly associated with DILI. Furthermore, the absence of G carriership of HLA-DQA*0102 could protect the patients from DILI without being associated with an effect on the isoniazid concentration.

Association between NAT2, CYP1A1, and CYP1A2 genotypes, heterocyclic aromatic amines, and prostate cancer risk: a case control study in Japan

BackgroundHeterocyclic aromatic amines (HAAs) may confer prostate cancer risk; however, the evidence is inconclusive and the activity of HAA-metabolizing enzymes is modulated by gene variants. The purpose of our study was to determine whether there was evidence of an association between HAA intake, polymorphisms in NAT2, CYP1A1, and CYP1A2 and prostate cancer risk in Japanese men.MethodsSecondary data analysis of an observational case control study was performed. Among 750 patients with prostate cancer and 870 healthy controls, 351 cases and 351 age-matched controls were enrolled for analysis. HAA intake was estimated using a food frequency questionnaire and genotypes were scored by TaqMan real-time PCR assay. Logistic regression analysis was conducted according to affected/control status.ResultsWe found that high HAA intake was significantly associated with an increased risk of prostate cancer (odds ratio (OR), 1.90; 95% confidence interval (95% CI), 1.40–2.59). The increased risk of prostate cancer was observed among individuals with the NAT2 slow acetylator phenotype (OR, 1.65; 95% CI, 1.04–2.61), CYP1A1 GA + GG genotype (OR, 1.27; 95% CI, 1.02–1.59), and CYP1A2 CA + AA genotype (OR, 1.43; 95% CI, 1.03–2.00). In addition, CYP1A1 GA + GG genotypes were associated with increased cancer risk in low (OR, 2.05; 95% CI, 1.19–3.63), moderate (OR, 1.72; 95% CI, 1.07–2.76), and high (OR, 2.86; 95% CI, 1.83–4.47) HAA intake groups.ConclusionsOur results suggest that high HAA intake is a risk factor of prostate cancer, and genotypes related to HAA metabolic enzymes can modulate the degree of the risk.

N-Acetyltransferase 2 Genotype-Dependent N-Acetylation of Hydralazine in Human Hepatocytes.

Hydralazine is used in the treatment of essential hypertension and is under investigation for epigenetic therapy in the treatment of neoplastic and renal diseases. N-acetyltransferase (NAT) 2 exhibits a common genetic polymorphism in human populations. After recombinant expression in yeast, human NAT2 exhibited an apparent Lineweaver-Burk constant (K-m) value (20.1 ± 8.8 μM) for hydralazine over 20-fold lower than the apparent K-m value (456 ± 57 μM) for recombinant human NAT1 (P = 0.0016). The apparent Vmax value for recombinant human NAT1 (72.2 ± 17.9 nmol acetylated/min/mg protein) was significantly (P = 0.0245) lower than recombinant human NAT2 (153 ± 15 nmol acetylated/min/mg protein), reflecting 50-fold higher clearance for recombinant human NAT2. Hydralazine NAT activities exhibited a robust acetylator gene dose response in cryopreserved human hepatocytes both in vitro and in situ. Hydralazine NAT activities in vitro differed significantly with respect to NAT2 genotype at 1000 (P = 0.0319), 100 (P = 0.002), and 10 μM hydralazine (P = 0.0029). Hydralazine NAT activities differed significantly (P < 0.001) among slow acetylator hepatocytes, (NAT2*5B/*5B > NAT2*5B/*6A > NAT2*6A/*6A). The in situ hydralazine N-acetylation rates differed significantly with respect to NAT2 genotype after incubation with 10 (P = 0.002) or 100 µM (P = 0.0015) hydralazine and were higher after incubation with 100 μM (10-fold) than with 10 μM (4.5-fold) hydralazine. Our results clearly document NAT2 genotype-dependent N-acetylation of hydralazine in human hepatocytes, suggesting that hydralazine efficacy and safety could be improved by NAT2 genotype-dependent dosing strategies.

Studies on N-Acetyltransferase (NAT2) Genotype Relationships in Emiratis: Confirmation of the Existence of Phenotype Variation among Slow Acetylators.

Individuals with slow N-acetylation phenotype often experience toxicity from drugs such as isoniazid, sulfonamides, procainamide, and hydralazine, whereas rapid acetylators may not respond to these medications. The highly polymorphic N-acetyltransferase 2 enzyme encoded by the NAT2 gene is one of the N-acetylators in humans with a clear impact on the metabolism of a significant number of important drugs. However, there are limited studies on N-acetylation phenotypes and NAT2 genotypes among Emiratis, and thus this study was carried out to fill this gap. Five hundred seventy-six Emirati subjects were asked to consume a soft drink containing caffeine (a nontoxic and reliable probe for predicting the acetylation phenotype) and then provide a buccal swab along with a spot urine sample. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine the genotype of each individual. Phenotyping was carried out by analyzing the caffeine metabolites using high-performance liquid chromatography (HPLC) analysis. We found that 78.5%, 19.1%, and 2.4% of the Emirati subjects were slow, intermediate, and rapid acetylators, respectively. In addition, we found that 77.4% of the subjects were homozygous or heterozygous for two nonreference alleles, whereas 18.4% and 4.2% were heterozygous or homozygous for the reference allele (NAT2*4), respectively. The most common genotypes found were NAT2*5B/*7B, NAT2*5B/*6A, NAT2*7B/*14B, and NAT2*4/*5B, with frequencies of 0.255, 0.135, 0.105, and 0.09, respectively. The degree of phenotype/genotype concordance was 96.2%. The NAT2*6A/*6A, NAT2*6A/*7B, NAT2*7B/*7B, and NAT2*5A/*5B genotypes were found to be associated with the lowest 5-acetylamino-6-formylamino-3-methyluracil/1-methylxanthine (AFMU/1X) ratios. There is a high percentage of slow acetylators among Emiratis, which correlates with the presence of nonreference alleles for the NAT2 gene. Individuals who carried NAT2*6A/*6A, NAT2*6A/*7B, NAT2*7B/*7B, or NAT2*5A/*5B genotypes might be at higher risk of toxicity with some drugs and some diseases compared to others, as these genotypes are associated with the slowest acetylation status.

Arylamine N-acetyltransferase 2 genotype-dependent N-acetylation of isoniazid in cryopreserved human hepatocytes

Cryopreserved human hepatocytes were used to investigate the role of arylamine N-acetyltransferase 2 (NAT2; EC 2.3.1.5) polymorphism on the N-acetylation of isoniazid (INH). NAT2 genotype was determined by Taqman allelic discrimination assay and INH N-acetylation was measured by high performance liquid chromatography. INH N-acetylation rates in vitro exhibited a robust and highly significant (P<0.005) NAT2 phenotype-dependent metabolism. N-acetylation rates in situ were INH concentration- and time-dependent. Following incubation for 24h with 12.5 or 100 µmol/L INH, acetyl-INH concentrations varied significantly (P = 0.0023 and P = 0.0002) across cryopreserved human hepatocytes samples from rapid, intermediate, and slow acetylators, respectively. The clear association between NAT2 genotype and phenotype supports use of NAT2 genotype to guide INH dosing strategies in the treatment and prevention of tuberculosis.

Association Between NAT2 Polymorphisms and Prostate Cancer

Background: NAT2 enzyme involved in bioconversion of aromatic amines, heterocyclic arylamines and certain drugs into electrophilic ions that can be important initiators in tumorigenesis process. Objectives: The aim of this study was to assess the possible association between NAT2 polymorphisms (857 G > A, 481 T > C, and 590 G > A) and risk of prostate cancer (PC). Methods: Totally, 207 benign prostate hyperplasia (BPH) and 147 PC Iranian patients were evaluated. NAT2 genotypes were detected by restriction fragment length polymorphism (RFLP). Multiple logistic regression models were used to estimate the odds ratios for the association between presence of each genotype and developing PC. Results: For NAT2 G857A, the frequency of AA and AG genotypes was lower among PC patients compared to those without it (1.01% vs. 0 and 55.88% vs. 54.55%, respectively; P = 0.7). For NAT2 T481c, the odds ratios for the association of TT and CT genotypes with PC were 0.65 and 0.55, respectively, which were not statistically significant (P = 0.5 and P = 0.09, respectively). For NAT2 G590a, both AA (11.11% vs. 12.87%) and AG (45.83% vs. 52.48%) genotypes were significantly more common among PC patients compared to BPC patients (P = 0.008). However, none of the relevant odds ratios were statistically significant (OR = 2.2, P = 0.2 and OR = 1.72, P = 0.1, respectively). Among PC patients, CT genotype of T481C caused more than 4-fold significant increase in the risk of developing advanced stages of PC. Conclusions: Our study represented credible evidence that carrying G857A, G590A and T481C polymorphisms of NAT2 may not affect developing PC, its grading or invasion, but heterozygote genotype of T481C polymorphism (Rapid acetylator) can be associated with more advanced stages of cancer earlier in life. Further longitudinal studies with larger sample sizes are needed to more precisely assess the genetic risk factors of PC.

P3.02c-001 Phase I Study of Salazosulfapyridine Targeting Cancer Stem Cells in Combination with CDDP and Pemetrexed for Chemo-Naïve Advanced Non-Sq NSCLC: Topic: Targeted Therapy

Variant splicing isoforms of CD44 (CD44v) are a marker of cancer stem cells (CSCs) in solid tumors. CD44v stabilizes the glutamate-cystine transporter subunit xCT and thereby promotes synthesis of the intracellular antioxidant glutathione and protects CSCs from oxidative stress. Salazosulfapyridine (SASP) is an inhibitor of xCT activity, and, in combination with cisplatin (CDDP), it attenuates the increase in the proportion of CD44v-positive tumor cells during the growth of tumor xenografts in mice. Individuals with advanced (stage IIIB or IV) nonsquamous non–small cell lung cancer are eligible to enroll in a phase I dose-escalation study (standard 3+3 design) of SASP in combination with CDDP and pemetrexed (PEM) as first-line treatment. Patients receive SASP daily as well as CDDP (75 mg/m2) and PEM (500 mg/m2) on day 1 of a 21-day cycle. The primary end point is the percentage of patients who experience dose-limiting toxicity (DLT) between administration of the first dose of SASP (day 1) and day 21. From April 2015 to January 2016, 15 patients were enrolled in the study (mean age, 64 years; age range, 42–74 years; male/female ratio, 10/5; ECOG performance status 0/1 ratio, 6/9). Immunohistochemical staining of tumor biopsy specimens revealed that the proportion of CD44v-positive cells was >10% in 9 patients before SASP treatment. No DLT was observed in the first three patients treated at SASP dose level 1 (500 mg TID) or those treated at dose level 2 (1000 mg TID). At dose level 3 (1500 mg TID), two of three patients experienced a DLT (anorexia of grade 3). We enrolled additional patients at dose level 2 and two of the total of five patients treated at this dose level experienced DLTs (hypotension or pneumonitis, each of grade 3). To confirm the safety of dose level 1, we enrolled additional patients at this dose level and one of the total of six patients treated at this dose level experienced DLTs (AST and ALT elevation, each of grade 3). Exposure of SASP following oral administration varied markedly among individuals according to ABCG2 and NAT2 genotypes as previously reported. SASP 500 mg TID was the recommended dose when administered with CDDP plus PEM.

Pharmacokinetics of thrice-weekly rifampicin, isoniazid and pyrazinamide in adult tuberculosis patients in India.

To study the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in adult tuberculosis (TB) patients and examine factors that influence drug pharmacokinetics. Adult TB patients (n = 101) receiving thrice-weekly anti-tuberculosis treatment in the Revised National TB Control Programme (RNTCP) were studied. The study was conducted at steady state after directly observed drug administration. RMP, INH and PZA concentrations were estimated using high-performance liquid chromatography and NAT2 genotyping by real-time polymerase chain reaction. RMP peak concentration (Cmax) was sub-therapeutic (<8 μg/ml) in 88% of the patients. The Cmax of RMP, INH and PZA at 2 h was observed in respectively 83.2%, 97.0% and 92.1% of the patients. The Cmax and area under the curve from 0 to 8 h (AUC0-8) of PZA was lower in TB patients with diabetes mellitus than in non-diabetics. Significant associations were observed between the Cmax and the AUC0-8 of RMP, INH and PZA with drug doses; RMP with category of treatment; INH with smoking, body mass index and N-acetyl transferase 2 genotype; and PZA with sex and smoking. Several risk factors for drug concentration variations were identified. Two-hour post-dosing drug concentrations mimicked Cmax. A high proportion of TB patients had RMP Cmax below the expected range, which is a matter of concern.

Rapid identification of the NAT2 genotype in tuberculosis patients by multicolor melting curve analysis.

NAT2 genotype is an indicator for isoniazid dosage adjusting for tuberculosis treatment. Multicolor melting curve analysis (MMCA) was evaluated as a potential method for NAT2 genotyping. 352 blood samples were analyzed by MMCA kit (Zeesan Biotech Co., Xiamen, China) targeting NAT2 SNPs at T341C, C481T, G590A and G857A, and direct sequencing was used as control. The sensitivity, specificity and accuracy of the MMCA assay for rapid NAT2 genotype detection were 97.9, 99.6 and 99.1% respectively, whereas for intermediate genotypes the values were 99.5, 98.7 and 99.1%, respectively, and for slow genotypes the values were 100% for the three aspects. The 24 saliva and blood for the control samples were also successfully analyzed using the MMCA assay, both produced uniform outcomes. The MMCA assay described in our study is very promising for the efficient determination of NAT2 genotype, and can facilitate the personalized dosing of isoniazid.

NAT2 Genotype Pattern among Tuberculosis Patients Receiving Fixed-Dose Combination of Antituberculosis

Abstract: Drug-induced liver injury (DILI) has known to be very responsible for more than 50% of acute liver failure cases in United States. Nowadays DILI’s treatment is only focused on supportive therapy as well as stopping the medication responsible for it. The incidence of antituberculosis liver injury (ATLI) in the world was ranging between 13-48%. Acetylator status and NAT2 genotype pattern related to it were two factors that have strong relationship to ATLI incidence. Slow acetylator was reported to significantly increase ATLI incidence in many studies. The proportion of slow acetylator were varies in many countries, ranging between 6-55% and these were strongly related to NAT2 genotype pattern. This study aimed to investigate NAT2 genotype pattern in tuberculosis patients receiving fixed-dose combination of antituberculosis. As many as 35 tuberculosis patients attending Outpatient Clinic of Sanglah Hospital were included in this cross sectional study. Identification of NAT2 genotype was performed with PCR-RFLP assay using KpnI and BamHI restriction enzymes. This study reveals the proportion of NAT2*4/*4; *4/*5 and *5/*5 genotype were 54.3%; 37.1%; dan 8.6%, respectively, whereas the proportion of NAT2*4/*4; *4/*7 and *7/*7 genotype were 11.4%; 71.4%; dan 17.2%, respectively. Keywords: antituberculosis, liver injury, N-acetyl transferase 2, acetylator, gene