Actively proliferating cancer cells require sufficient amount of NADH and NADPH for biogenesis and to protect cells from the detrimental effect of reactive oxygen species. As both normal and cancer cells share the same NAD biosynthetic and metabolic pathways, selectively lowering levels of NAD(H) and NADPH would be a promising strategy for cancer treatment. Targeting nicotinamide phosphoribosyltransferase (NAMPT), a rate limiting enzyme of the NAD salvage pathway, affects the NAD and NADPH pool. Similarly, lowering NADPH by mutant isocitrate dehydrogenase 1/2 (IDH1/2) which produces D-2-hydroxyglutarate (D-2HG), an oncometabolite that downregulates nicotinate phosphoribosyltransferase (NAPRT) via hypermethylation on the promoter region, results in epigenetic regulation. NADPH is used to generate D-2HG, and is also needed to protect dihydrofolate reductase, the target for methotrexate, from degradation. NAD and NADPH pools in various cancer types are regulated by several metabolic enzymes, including methylenetetrahydrofolate dehydrogenase, serine hydroxymethyltransferase, and aldehyde dehydrogenase. Thus, targeting NAD and NADPH synthesis under special circumstances is a novel approach to treat some cancers. This article provides the rationale for targeting the key enzymes that maintain the NAD/NADPH pool, and reviews preclinical studies of targeting these enzymes in cancers.

Background: As pediatric tuberculosis (TB) globally is still reported challenging in diagnosis, to date, a lot of efforts have been established to eliminate the disease including proper treatment regimen using anti-TB drugs. However, antituberculosis drug-induced hepatotoxicity (ADIH) is known to interfere the success of the prescribed therapy. ADIH was found to be correlated with polymorphisms of NAT2 gene, that is responsible to transcript the NAT2 enzyme, a metabolizer of isoniazid (INH). The most common NAT2 gene polymorphisms in Asian population associated with ADIH are rs1041983, rs1799929, rs1799930 and rs1799931. The study aimed to investigate the 4 single nucleotide polymorphisms (SNPs) in pediatric TB that experienced ADIH. Methods: We conducted a case–control study comparing 31 each of pediatric TB experience with and without ADIH. All pediatric TB was selected from 451 pediatric TB Registry of Respirology Division, Department of Child Health Faculty of Medicine Universitas Padjadjaran/Dr Hasan Sadikin Hospital during January 2016 to July 2018. Genomic DNA PCR and sequencing to identify polymorphisms of rs1041983, rs1799929, rs1799930 and rs1799931 were performed in both groups. Data analysis was performed using the Epi info Ver. 7 software. Results: Thirty-one pediatric TB experiences with and without ADIH were enrolled in this study. SNP rs1041983 significantly affected the occurrence of ADIH (OR 2.39, CI 95% (1.15– 4.96), p=0.019). The rs1799929, rs1799930 and rs1799931 did not significantly affect the occurrence of ADIH (p=0.133, p=0.150 and p=0.659, respectively). Conclusion: Polymorphism SNP rs1041983 had association with the occurrence of ADIH.

Indonesia adalah negara dengan jumlah penderita tuberkulosis (TB) terbanyak kedua di dunia. Diabetes melitus (DM) merupakan salah satu komorbid TB. Arylamine N-acetyltransferase 2 (NAT2) adalah enzim yang berfungsi memetabolisir isoniazid (INH) yang disandi oleh gen NAT2. Gen NAT2 memiliki sejumlah polimorfisme dan dapat menentukan kemampuan seseorang untuk memetabolisir obat yang disebut status asetilator. Pada individu dengan status asetilator lambat, INH dimetabolisir dengan lambat sehingga memungkinkan terjadi intoksikasi hati. Pada TB dengan DM (TBDM) status asetilator lambat dapat membuat pengobatan TB maupun DM menjadi kurang optimal. Penelitian ini bertujuan mengeksplorasi status asetilator pasien TBDM di RSUD Prof. WZ Johannes Kupang periode Juni–November 2011. Pada penelitian potong lintang ini DNA dari darah 122 pasien TB diisolasi dan gen NAT2 kemudian diamplifikasi dan disekuensing untuk diketahui status asetilatornya. Hasil penelitian menunjukkan terdapat 5 pasien yang memiliki glukosa serum >200 mg/dL yang dikategorikan sebagai pasien TBDM. Pada pasien TBDM didapatkan seorang dengan status asetilator cepat (NAT2*4/NAT2*4), 2 orang dengan status asetilator sedang (NAT2*13A/NAT2*6J), dan 2 orang dengan status asetilator lambat (NAT2*5/NAT2*5G, NAT2*6A/ NAT2*6A, NAT2*7B/ NAT2*7B). Pada pasien TB yang dipilih secara random berdasar usia dan jenis kelamin serupa dengan TBDM didapatkan 2 orang dengan status asetilator cepat (NAT2*4/NAT2*4) dan 3 orang dengan asetilator sedang (NAT2*4/NAT2*6A, NAT2*13A/NAT2*6J). TBDM yang memiliki status asetilator lambat berpotensi memiliki masalah ganda dalam terapi, selain dapat terjadi toksisitas hati akibat terapi dengan INH, juga dapat mengakibatkan pengobatan DM menjadi tidak optimal. Perlu dilakukan peneltian lebih lanjut terkait farmakogenetik pada TBDM. [MKB. 2016;49(1):61–6] Kata kunci: Asetilator, isoniazid, NAT2, farmakogenetik, tuberkulosis NAT2 Gene Acetylator Status of Tuberculosis and Tuberculosis with Diabetes Mellitus Patients in Kupang, Nusa Tenggara Timur Indonesia is the second highest country with TB patients in the world. Diabetes mellitus (DM) is a comorbid of TB. Arylamine N-acetyltransferase 2 (NAT2), encoded by the NAT2 gene, is an enzyme that metabolizes isoniazid (INH). NAT2 gene has some polimorphysims that may play a role in INH acetylating process. Those who are slow acetylators may develop liver intoxication as a consequence of slow INH metabolism process. Slow acetylator TBDM patients may complicate both TB and DM treatment, causing them to be less optimal. The aim of this study was to explore the acetylator status of TBDM patients in Kupang, Indonesia. A cross-sectional study was conducted by obtaining DNA of 122 TB patients in Kupang in June–November 2011. NAT2 gene was amplified and sequenced to determine the acetylator status. There were 5 TB patients who had a glucose serum level of >200mg/dL and was catagorized as TBDM. Result showed that there was 1 TBDM patient who was a rapid acetylator (NAT2*4/NAT2*4), 2 patients as intermediate acetylators (NAT2*13A/NAT2*6J), and 2 patients as slow acetylators (NAT2*5/NAT2*5G, NAT2*6A/ NAT2*6A, NAT2*7B/ NAT2*7B). Meanwhile, there were 2 TB patients who was rapid acetylators (NAT2*4/NAT2*4) and 3 patients as intermediate acetylators (NAT2*4/NAT2*6A, NAT2*13A/NAT2*6J). Slow NAT2 acetylator TBDM patients potentially face more problems during therapy. As INH may cause liver intoxication, these patients may also experience unoptimum DM treatment. Therefore, it is strongly recommended to do a study on the role of pharmacogenomics in TBDM. [MKB. 2016;49(1):61–6] Key words: Acetylator, isoniazid, NAT2, pharmacogenetics, tuberculosis   DOI: 10.15395/mkb.v49n1.989

BACKGROUND: N-acetyltransferase-2 (NAT2) enzyme, encoded by NAT2 gene, plays a key role in metabolism of anti-tuberculosis (TB) drug isoniazid. Polymorphisms in NAT2 gene may result in different responses to TB therapy. Since TB prevalence in the eastern part of Indonesia is high, the aim of this study is to explore the distribution of NAT2 gene polymorphisms among population from Kupang, Nusa Tenggara Timur.METHODS: A total of 234 respondents were included from Kupang in 2012. Polymorphisms of NAT2 gene were examined using mass screening platform and the genotypes distribution were presented in percentage. To confirm NAT2 gene polymorphisms, polymerase chain reaction (PCR)-sequencing was performed in a subset of population.RESULTS: The polymorphisms of NAT2 gene showed that the distribution of rs1801279 for GG genotype was 100%; whereas the genotype distribution of rs1799930 for GG, GA and AA was 57%, 35.1% and 7.9%, respectively. In a subset of individuals (n13), acetylator status was well determined by PCR-sequencing, resulting in individual with wild type fast acetylator (NAT2*4; n4), intermediate (NAT2*4/*5 or NAT2*4/*6 or NAT2*4/*7; n7) and poor acetylators (NAT2*6/*6 or NAT2*7/*7; n2).CONCLUSION: The amino acid change in rs1799930 result in intermediate and poor acetylator status in Kupang population. This may lead to suboptimal response of TB therapy. Assessing acetylator status before TB therapy is important and may serve as personalized INH therapy.KEYWORDS: NAT2 gene, polymorphism, acetylator status, Kupang