[Pharmacogenomic data for personalized medicines]

FDA issued guidance for industry regarding pharmarcogenomic data submission this year. Polymorphic cytochrome P450 2D6 and thiopurine S-methyltransferase in patients are now considered biomarkers for drugs which are predominantly metabolized by these enzymes. This article reviews current efforts to treat pharmacogenomic data for new drug development and personalized medicines.

Genotype-phenotype correlation between the polymorphic UGT2B17 gene deletion and NNAL glucuronidation activities in human liver microsomes

The nicotine-derived tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is one of the most potent and abundant procarcinogens found in tobacco and tobacco smoke, and glucuronidation of its major metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), is an important mechanism for NNK detoxification. In cigarette smokers and tobacco chewers, there is a wide variation in the urinary levels of the ratio of NNAL to NNAL glucuronide (NNAL-Gluc). To determine whether genetic variation plays a potential role in this inter-individual variability, NNAL-glucuronidating activities were analysed in a series of human liver microsomal specimens and compared with UGT2B17 deletion genotypes in the same subjects. Assays performed in vitro demonstrated that over-expressed UGT2B17 exhibits high O-glucuronidating activity against NNAL. When stratifying subjects by UGT2B17 genotype, a significant or near-significant decrease in NNAL-O-Gluc formation was observed in liver microsomes from individuals who were either heterozygous [(+/0), P=0.07] or homozygous [(0/0), P=0.016] for the UGT2B17 deletion compared to liver microsomes from individuals with intact UGT2B17 alleles [(+/+)]. There was a significant (P<0.01) association between the level of liver microsomal NNAL-O-glucuronide formation and increasing numbers of the UGT2B17 null alleles in the liver microsomal specimens examined in this study, and a significant decrease in NNAL-O-Gluc formation was observed when comparing liver microsomes from individuals who had at least one UGT2B17 allele deleted [(+/0)+(0/0)] versus microsomes from UGT2B17 (+/+) subjects (P=0.004). When stratifying by the median value of NNAL-O-Gluc formation activity, a significantly (P=0.015) higher number of subjects with liver microsomes having low NNAL-O-Gluc formation activity contained the UGT2B17 null genotype compared to subjects with liver microsomes exhibiting high NNAL-O-Gluc formation activity. When stratifying by UGT2B7/UGT2B17 haplotypes, the association between the level of liver microsomal NNAL-O-glucuronide formation and increasing numbers of the UGT2B17 null allele was at the level of statistical significance for subjects with the UGT2B7 (*1/*2) (P=0.05) or UGT2B7 (*2/*2) (P<0.02) genotypes. These data suggest that the UGT2B17 deletion polymorphism is associated with a reduced rate of NNAL detoxification in vivo and may increase individual susceptibility to tobacco-related cancers.

[SNPs associated with adverse effects]

In recent years, pharmacogenomics have received much attention from the increased expectations for so-called order-made medicine. It is experientially clear that inter-individual differences exist in the degree of efficacy and occurrence of adverse effects. These inter-individual differences are observed not only among anticancer chemotherapeutics but in almost all drugs. Several studies have revealed that genetic factors are involved in these inter-individual differences. To date, the relationships have been revealed between adverse effects of some anticancer drugs and polymorphisms of drug metabolizing genes. Such relationships include 5-FU and DPYD gene, methotorexate and MTHFR gene, irinotecan and UGT 1A1 gene and 6-MP and TPMT gene. By using information on these polymorphisms, it will be possible to predict the occurrence of adverse effects before using anticancer drugs. In particular, information on polymorphisms related to the possibly adverse effects of irinotecan is now given in its package leaflet. This means that order-made medicine is a step closer. In this review, we discuss the relationships between polymorphisms of genes and the adverse effects of anticancer drugs. Furthermore, we want to suggest the direction of further pharmacogenomic studies with an eye to the realization of order-made medicine.

Tissue-specific, Inducible, and Hormonal Control of the Human UDP-Glucuronosyltransferase-1 (UGT1) Locus

The human UDP-glucuronosyltransferase 1 (UGT1) locus spans nearly 200 kb on chromosome 2 and encodes nine UGT1A proteins that play a prominent role in drug and xenobiotic metabolism. Transgenic UGT1 (Tg-UGT1) mice have been created, and it has been demonstrated that tissue-specific and xenobiotic receptor control of the UGT1A genes is influenced through circulating humoral factors. In Tg-UGT1 mice, the UGT1A proteins are differentially expressed in the liver and gastrointestinal tract. Gene expression profiles confirmed that all of the UGT1A genes can be targeted for regulation by the pregnane X receptor activator pregnenolone-16alpha-carbonitrile (PCN) or the Ah receptor ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In addition, the selective induction of glucuronidation activity toward lamotrigine, ethinyl estradiol, chenodeoxycholic acid, and lithocholic acid by either PCN or TCDD in small intestine from Tg-UGT1 mice corresponded to expression of the locus in this tissue. Induction of UGT1A1 by PCN and TCDD is believed to be highly dependent upon glucocorticoids, because submicromolar concentrations of dexamethasone actively promote PCN and TCDD induction of UGT1A1 in Tg-UGT1 primary hepatocytes. The role of hormonal control of the UGT1 locus was further verified in pregnant and nursing Tg-UGT1 mice. In maternal 14-day post-conception Tg-UGT1mice, liver UGT1A1, UGT1A4, and UGT1A6 were induced, with the levels returning to near normal by birth. However, maternal liver UGT1A4 and UGT1A6 were dramatically elevated and maintained after birth, indicating that these proteins may play a critical role in maternal metabolism during lactation. With expression of the UGT1 locus confirmed in a variety of mouse tissues, these results suggested that the Tg-UGT1 mice will be a useful model to examine the regulatory and functional properties of human glucuronidation.

The role of UGT1A1*28 mutation in jaundiced infants with hypertrophic pyloric stenosis

Hypertrophic pyloric stenosis (HPS) may be accompanied by jaundice, a condition referred to as the icteropyloric syndrome (IPS). It has long been suspected that the etiology of IPS is an early manifestation of Gilbert's syndrome (GS). Clinical features common to both GS and IPS include jaundice precipitated by fasting and improved with feeding. Prevalence of jaundice in HPS is similar to that of clinically apparent GS in the general population. Discovery of a mutation in the promoter region of the bilirubin uridine diphosphate glucuronosyl transferase gene (UGT1A1*28) as the most common cause of GS has provided a tool to determine the role of GS in IPS. The aims of this study were to determine 1) the prevalence of IPS in a large group of infants with HPS, 2) whether disease severity contributed to the manifestation of IPS, and 3) whether GS played a role in IPS. Radioactive PCR and sequencing were used to determine the presence of UGT1A1*28 mutations. We determined a prevalence of IPS of 14.3% in HPS. Infants with IPS had significantly higher levels of alkalosis than infants with HPS alone. GS mutations were 4-fold higher in IPS (43.8%) than HPS (10.7%). In conclusion, the frequency of jaundice in HPS is similar to that of clinically apparent GS in the general population. Manifestation of IPS results from a more severe degree of metabolic disturbance and the presence of GS mutations.

Adenovirus-mediated gene transfer of mutated IkappaB kinase and IkappaBalpha reveal NF-kappaB-dependent as well as NF-kappaB-independent pathways of HAS1 activation

It has become increasingly clear that hyaluronan is more than the simple matrix molecule it was once thought to be but instead takes part in a multitude of biological functions. Three genes encode for hyaluronan synthases (HAS). We demonstrated earlier that HAS2 and HAS3 are constitutively activated in type-B synoviocytes (fibroblast-like synoviocytes) and, furthermore, that the only gene that readily responds to stimulation with a series of proinflammatory cytokines is HAS1. Here we probe the involvement of the transcription factor NF-kappaB in induced and noninduced HAS activation. Transforming growth factor (TGF) beta1 as well as interleukin (IL)-1beta are both strong inducers of HAS1 transcription. Stimulation of fibroblast-like synoviocytes with IL-1beta resulted in rapid degradation of IkappaBalpha, an event that was preceded by IkappaBalpha phosphorylation. Interestingly, TGFbeta1 neither affected IkappaBalpha levels, nor did it cause phosphorylation of IkappaBalpha. In addition, TGFbeta1 had no effect on IkappaBbeta and IkappaBepsilon levels. Electrophorectic mobility shift assays demonstrate that IL-1beta is a potent inducer of NF-kappaB translocation; however, TGFbeta1 treatment did not result in shifting bands. Two adenovirus constructs were used to further clarify differences in TGFbeta1- and IL-1beta-induced HAS1 activation. Overexpressing IkappaBalpha completely abolished the IL-1beta effect on HAS1 but did not interfere with TGFbeta1-induced HAS1 mRNA accumulation. Identical results were obtained when a dominant negative IKK was overexpressed. Interestingly, neither overexpression of IkappaBalpha nor of IKK had any effect on HAS2 and HAS3 mRNA levels. Taken together, HAS1 can be activated by distinct pathways; IL-1beta utilizes NF-kappaB, and TGFbeta1 does not. Furthermore, HAS2 and HAS3 are activated without the involvement of NF-kappaB.

Activity and expression of various isoforms of uridine diphosphate glucuronosyltransferase are differentially regulated during hepatic regeneration in rats

PURPOSE

Glucuronidation pathway is very important in the detoxification of endogenous and exogenous compounds. The objective of this study was to evaluate the activity and expression of various hepatic uridine diphosphate glucuronosyltransferases (UGTs) in rats at various time points after initiation of hepatic regeneration by partial hepatectomy (PHx).

METHODS

The mRNA expression of various UGTs was evaluated using real-time polymerase chain reaction (real-time PCR) with specific primers. The in vitro activity of UGTs was evaluated using different substrates such as estradiol (UGT1A1), acetaminophen (UGT1A6/7), morphine (UGT2B1), testosterone (UGT2B1/3/6), androsterone (UGT2B2), and (-)-borneol (UGT2B12).

RESULTS

Whereas the activity and mRNA expression of UGT1A1, UGT2B1, UGT2B1/3/6, UGT2B2, and UGT2B12 were lower, the activity and mRNA expression of UGT1A6/7 were preserved during hepatic regeneration. The mRNA expression of UGT2B8 was down-regulated, whereas the mRNA expression of UGT1A5 and UGT1A8 was not altered by PHx. The mRNA expression of UGT1A2 and UGT1A3 was increased during hepatic regeneration.

CONCLUSION

UGT-mediated drug-metabolizing ability of the liver was altered differentially in the regenerating rat liver. Individualized dosing regimen for different UGT substrates may be needed when using such substrates of these enzymes in patients with a regenerating liver, especially during the early postoperative period. However, the glucuronide conjugating capacity of the liver in the donor of a living donor liver transplantation is expected to completely return to normal with time after surgery.

Hyaluronan secretion by synoviocytes is mechanosensitive

Hyaluronan (HA) is an essential component of synovial interstitial matrix and synovial fluid, but the link between its production and joint use is unclear. HA secretion is enhanced by joint distension in vivo, but direct proof that synoviocytes exhibit mechanosensitive HA secretion is lacking. We tested this in vitro. Primary rabbit synoviocyte (PRS) cultures from microdissected synovial intima were subjected to 180 min of maintained 10% static stretch, or to 10 min of 10% static stretch followed by 170 min relaxation, in a Flexcell 2000 apparatus. Stretch stimulated HA secretion into the medium over 3 h by 57%. Notably, a short stretch (10 min) was as effective as sustained stretch. Actinomycin D and cycloheximide abolished stretch-stimulated HA secretion and also reduced basal HA secretion rate. RT-PCR showed that HAS2 was the major hyaluronan synthase expressed, but there was no increase in HAS2 mRNA (or other isoforms) in continuously stretched cells, and only a small increase (20%) at 180 min in cells stretched for the first 10-30 min. However HAS2 transcription increased 10-fold in response to TGF-beta1 and IL-1beta. Thus HA secretion by intimal synoviocytes is regulated by a mechanosensitive pathway which depends on transcription and de novo protein synthesis, possibly of HAS2, but also of other proteins involved in HA secretion.

Frequencies of A(TA)7TAA, G71R, and G493R mutations of the UGT1A1 gene in the Malaysian population

BACKGROUND

Gilbert syndrome is caused by defects in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene. These mutations differ among different populations and many of them have been found to be genetic risk factors for the development of neonatal jaundice.

OBJECTIVES

The objective was to determine the frequencies of the following mutations in the UGT1A1 gene: A(TA)7TAA (the most common cause of Gilbert syndrome in Caucasians), G71R (more common in the Japanese and Taiwanese population), and G493R (described in a homozygous Malay woman with Crigler-Najjar syndrome type 2) in a group of Malaysian babies with hyperbilirubinemia and a group of normal controls.

METHODS

The GeneScan fragment analysis was used to detect the A(TA)7TAA variant. Mutation screening of both G71R and G493R was performed using denaturing high performance liquid chromatography.

RESULTS

Fourteen out of fifty-five neonates with hyperbilirubinemia (25%) carried the A(TA)7TAA mutation (10 heterozygous, 4 homozygous). Seven out of fifty controls (14%) carried this mutation (6 heterozygous, 1 homozygous). The allelic frequencies for hyperbilirubinemia and control patients were 16 and 8%, respectively (p=0.20). Heterozygosity for the G71R mutation was almost equal among both groups (5.5% for hyperbilirubinemia patients and 6.0% for controls; p=0.61). One subject (1.8%) in the hyperbilirubinemia group and none of the controls were heterozygous for the G493R mutation (p=0.476).

CONCLUSIONS

The A(TA)7TAA seems more common than the G71R and G493R mutations in the Malaysian population.

Expression of cytochromes P450, conjugating enzymes and nuclear receptors in human hepatoma HepaRG cells

Most human hepatocyte cell lines lack a substantial set of liver-specific functions, especially major cytochrome P450 (P450)-related enzyme activities, making them unrepresentative of in vivo hepatocytes. We have used the HepaRG cells, derived from a human hepatocellular carcinoma, which exhibit a high differentiation pattern after 2 weeks at confluency to determine whether they could mimic human hepatocytes for drug metabolism and toxicity studies. We show that when passaged at low density, these cells reversed to an undifferentiated morphology, actively divided, and, after having reached confluency, formed typical hepatocyte-like colonies surrounded by biliary epithelial-like cells. By contrast, when seeded at high density, hepatocyte-like clusters retained their typical differentiated morphology. Transcripts of various nuclear receptors (aryl hydrocarbon receptor, pregnane X receptor, constitutive androstane receptor, peroxisome proliferator-activated receptor alpha), P450s (CYP1A2, 2C9, 2D6, 2E1, 3A4), phase 2 enzymes (UGT1A1, GSTA1, GSTA4, GSTM1), and other liver-specific functions were estimated by reverse transcriptase-quantitative polymerase chain reaction and were found to be expressed, for most of them, at comparable levels in both confluent differentiated and high-density differentiated HepaRG cells and in cultured primary human hepatocytes. For several transcripts, the levels were strongly increased in the presence of 2% dimethyl sulfoxide. Measurement of basal activities of several P450s and their response to prototypical inducers as well as analysis of metabolic profiles and cytotoxicity of several compounds confirmed the functional resemblance of HepaRG cells to primary cultured human hepatocytes. In conclusion, HepaRG cells constitute the first human hepatoma cell line expressing high levels of the major P450s involved in xenobiotic metabolism and represent a reliable surrogate to human hepatocytes for drug metabolism and toxicity studies.

Polymorphism of UDP-glucuronosyltransferase 1A7 gene: A possible new risk factor for lung cancer

UDP-glucuronosyltransferase (UGT) 1A7 detoxifies hydroxylated benzo-(alpha)-pyrenes and 2-hydroxyamino-1-methyl-6-phenylimidazo (4,5-beta) pyridine. The purpose of this study was to evaluate whether UGT1A7 polymorphisms are risk factors for lung cancer. A total of 113 Japanese patients with lung cancer and 178 healthy individuals were enrolled in this study. Genomic DNA was isolated from leukocytes. Exon 1 of UGT1A7 was sequenced. Homozygous UGT1A7*3/3 was observed in 17 (15%) of patients with lung cancer, and this incidence was significantly increased compared with the control group (4.5%, P=0.0036). Multivariate logistic regression analysis demonstrated a significant association of lung cancer with Brinkmann index (odds ratio=4.577, P=0.0004) and homozygous UGT1A7*3 (odds ratio=4.020, P=0.0037). The presence of UGT1A7 polymorphisms was associated with lung cancer. Homozygous UGT1A7*3 is a possible risk factor for lung cancer, at least in the Japanese population. Thus, determination of UGT1A7 polymorphisms may provide an important clue to preventive measures against lung cancer.

The over-expression of HAS2, Hyal-2 and CD44 is implicated in the invasiveness of breast cancer

Within tumors there appears to be an intricate balance between hyaluronan (HA) synthesis and degradation where the invading edges display increased HA metabolism. The metabolism of HA has not been characterized in breast cancer cell lines; therefore, this study quantitatively identifies and characterizes the enzymes responsible for the synthesis and degradation of HA while correlating gene expression to cancer cell invasiveness and HA receptor status. In ten well-established breast cancer cell lines, the expression of the genes for each hyaluronan synthase (HAS) and hyaluronidase (Hyal) isoform was quantitated using real-time and reverse transcriptase polymerase chain reaction (PCR). The synthesis and degradation rates of hyaluronan were determined by ELISA, while quantitation of HA receptors, CD44 and RHAMM was performed by comparative Western blotting. The molecular weight of HA synthesized by each HAS isoform and the degradation products of each hyaluronidase were characterized by size exclusion chromatography. It was demonstrated that highly invasive cell lines preferentially expressed the HAS2 and Hyal-2 isoforms, while less invasive cells expressed HAS3 and Hyal-3. There was a correlation between elevated levels of HA synthesis, CD44 expression and cancer cell migration thereby highlighting the pivotal role that HA metabolism plays in the aggressive breast cancer phenotype.

Cyclic mechanical stretch augments hyaluronan production in cultured human uterine cervical fibroblast cells

Hyaluronan (HA) a glycosaminoglycan with high affinity for water molecules stimulates local inflammatory reactions. Parturition causes a dramatic increase in the amount of HA fragments in the uterine cervix, thereby contributing to a rapid softening as well as opening of the cervical canal, i.e. cervical ripening. The aim of this study was to investigate the possible involvement of cyclic distension caused by labour in the augmentation of HA production during cervical ripening. Immunohistochemistry and/or RT-PCR detected hyaluronan synthase (HAS)1, 2 and 3 in samples of human cervical tissue obtained from pregnant women. Labour-like cyclic mechanical stretch for 24, 36 and 48 h significantly enhanced the secretion of HA, from cultured human uterine cervical fibroblast (CxF) cells, 128.7, 151.4 and 173.2%, respectively, concomitant with a significant augmentation of HAS1 (36, 48 h), HAS2 (24, 36 and 48 h) and HAS3 (48 h) mRNA expression. Cyclic mechanical stretch for 12, 36 and 48 h increased molecular size of the HA secreted from CxF cells. In conclusion, cyclic mechanical stretch of the uterine cervix caused by the presenting part of the fetus in labour may contribute to the increase in the secretion of HA during the process of cervical ripening.

Effects of variant UDP-glucuronosyltransferase 1A1 gene, glucose-6-phosphate dehydrogenase deficiency and thalassemia on cholelithiasis

AIM: To test the hypothesis that the variant UDP-glucuronosyltransferase 1A1 (UGT1A1) gene, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and thalassemia influence bilirubin metabolism and play a role in the development of cholelithiasis.

METHODS: A total of 372 Taiwan Chinese with cholelithiasis who had undergone cholecystectomy and 293 healthy individuals were divided into case and control groups, respectively. PCR and restriction fragment length polymorphism were used to analyze the promoter area and nucleotides 211, 686, 1 091, and 1 456 of the UGT1A1 gene for all subjects and the gene variants for thalassemia and G6PD deficiency.

RESULTS: Variation frequencies for the cholelithiasis patients were 16.1%, 25.8%, 5.4%, and 4.3% for A(TA)6 TAA/A(TA)7TAA (6/7), heterozygosity within the coding region, compound heterozygosity, and homozygosity of the UGT1A1 gene, respectively. Comparing the case and control groups, a statistically significant difference in frequency was demonstrated for the homozygous variation of the UGT1A1 gene (P = 0.012, χ² test), but not for the other variations. Further, no difference was demonstrated in a between-group comparison of the incidence of G6PD deficiency and thalassemia (2.7% vs 2.4% and 5.1% vs 5.1%, respectively). The bilirubin levels for the cholelithiasis patients with the homozygous variant-UGT1A1 gene were significantly different from the control analog (18.0 ± 6.5 and 12.7 ± 2.9 μmol/L, respectively; P<0.001, Student’s t test).

CONCLUSION: Our results show that the homozygous variation in the UGT1A1 gene is a risk factor for the development of cholelithiasis in Taiwan Chinese.

Expression patterns of hyaluronan, hyaluronan synthases and hyaluronidases indicate a role for hyaluronan in the progression of endometrial cancer

OBJECTIVE

The extracellular glycosaminoglycan hyaluronan (HA) and its degradative enzymes, hyaluronidases (Hyal), play important roles in tumor metastasis and angiogenesis. HA promotes tumor cell adhesion and migration, while its cleaved fragments stimulate angiogenesis. The aims of this study were to assess the levels of HA and how it might be regulated in endometrial cancer.

METHODS

Endometrial carcinomas were grouped according to histologic grade (Grade 1-3). HA histochemistry utilized a biotinylated HA binding peptide (n = 15), while HA synthase (HAS) immunohistochemistry utilized an antibody recognizing HAS1, HAS2 HAS3 (n = 24). Real-time RT-PCR was used to determine the mRNA expression of Hyal 1, Hyal 2 (n = 13) and Hyal 3 (n = 11) in endometrial carcinomas.

RESULTS

HA, its synthases and degradative enzymes were identified in endometrial carcinomas of all histologic grades. HA was predominantly localized to tumor-associated stroma. Semiquantitative analysis revealed increased HA levels with tumor grade, however, this increase only attained significance in Grade 2 carcinomas (P < 0.05). HA staining intensity scores were significantly associated with the presence of myometrial invasion (P < 0.05). Alternatively, HAS was predominantly localized in tumor epithelial cells, and its levels did not vary with tumor grade. Expression of Hyal 3 and Hyal 2 mRNA were >1000-fold and >30-fold greater respectively than that of Hyal 1 mRNA, the major Hyal expressed in other cancers. No Hyal type varied with tumor grade.

CONCLUSION

This is the first study to demonstrate the cellular localization of HA and its synthases and that Hyal 3 mRNA is predominant in endometrial cancer. The results suggest a role for elevated HA in endometrial cancer progression.

Genetic polymorphisms in human SULT1A1 and UGT1A1 genes associate with breast tumor characteristics: a case-series study

INTRODUCTION

Estrogens are important in breast cancer development. SULT1A1 and UGT1A1 catalyze estrogen metabolism and are polymorphic. The SULT1A1*2 protein exhibits low activity, and a TA repeat within the UGT1A1 promoter alters the level of expression of the protein. We hypothesized that the SULT1A1*2 allozyme has decreased capacity to sulfate estrogens, that the SULT1A1*2 allele conferred increased capacity of cells to proliferate in response to estrogens, and that individuals with the variant SULT1A1 and UGT1A1 genotypes exhibited different breast tumor characteristics.

METHODS

The capacity for SULT1A1*2 to sulfate 17beta-estradiol and the capacity for cells expressing SULT1A1*1 or SULT1A1*2 to proliferate in response to 17beta-estradiol was evaluated. A case-series study was performed in a total of 210 women with incident breast cancer, including 177 Caucasians, 25 African-Americans and eight women of other ethnic background. The SULT1A1 and UGT1A1 genotypes were determined and a logistic regression model was used to analyze genotype-phenotype associations.

RESULTS

We determined that the SULT1A1*1/*1 high-activity genotype was associated with tumor size <or=2 cm (odds ratio = 2.63, 95% confidence interval = 1.25-5.56, P = 0.02). Individuals with low-activity UGT1A1 genotypes (UGT1A1*28/*28 or UGT1A1*28/*34) were more likely to have an age at diagnosis >or=60 years (odds ratio = 3.70, 95% confidence interval = 1.33-10.00, P = 0.01). Individuals with both SULT1A1 and UGT1A1 high-activity genotypes had low tumor grade (odds ratio = 2.56, 95% confidence interval = 1.04-6.25, P = 0.05). Upon stratification by estrogen receptor status, significant associations were observed predominantly in estrogen receptor-negative tumors.

CONCLUSION

The data suggest that genetic variation in SULT1A1 and UGT1A1 may influence breast cancer characteristics and might be important for breast cancer prognosis.

Hyaluronic acid production in Bacillus subtilis

The hasA gene from Streptococcus equisimilis, which encodes the enzyme hyaluronan synthase, has been expressed in Bacillus subtilis, resulting in the production of hyaluronic acid (HA) in the 1-MDa range. Artificial operons were assembled and tested, all of which contain the hasA gene along with one or more genes encoding enzymes involved in the synthesis of the UDP-precursor sugars that are required for HA synthesis. It was determined that the production of UDP-glucuronic acid is limiting in B. subtilis and that overexpressing the hasA gene along with the endogenous tuaD gene is sufficient for high-level production of HA. In addition, the B. subtilis-derived material was shown to be secreted and of high quality, comparable to commercially available sources of HA.

Genetic polymorphisms of UGT1A6 in a Japanese population

Thirteen single nucleotide polymorphisms (SNPs), including 6 novel ones, were found in exon 1 and its flanking region of UDP-glucuronosyltransferase (UGT) 1A6 from 195 Japanese subjects. Several novel SNPs were identified, including 269G>A (R90H), 279A>G (S93S), and 308C>A (S103X) in exon 1, and IVS1+109C>T, IVS1+120A>G, and IVS1+142C>T in the intron downstream of exon 1. Among these SNPs, 308C>A confers termination of translation at codon 103, resulting in the production of an immature protein that probably lacks enzymatic activity. The allele frequencies were 0.003 for all the 6 SNPs. In addition, the 3 known nonsynonymous SNPs were detected: 19T>G (S7A), 541A>G (T181A), and 552A>C (R184S) with frequencies of 0.226, 0.218, and 0.226, respectively. High linkage disequilibrium was observed among 19T>G (S7A), 315A>G (L105L), 541A>G (T181A), 552A>C (R184S), and IVS1+130G>T, as reported in Caucasian and African-American populations. Then, 11 haplotypes in UGT1A6 were estimated. The novel nonsynonymous variant, 269A or 308A, was shown to be located on the same DNA strand together with 19G, 315G, 541G, 552C, and IVS1+130T. Our results provide fundamental and useful information for genotyping UGT1A6 in the Japanese, and probably Asian populations.

Gilbert syndrome and the development of antiretroviral therapy-associated hyperbilirubinemia

BACKGROUND

Unconjugated hyperbilirubinemia results from Gilbert syndrome and from antiretroviral therapy (ART) containing protease inhibitors. An understanding of the interaction between genetic predisposition and ART may help to identify individuals at highest risk for developing jaundice.

METHODS

We quantified the contribution of UGT1A1*28 and ART to hyperbilirubinemia by longitudinally modeling 1386 total bilirubin levels in 96 human immunodeficiency virus (HIV)-infected individuals during a median of 6 years.

RESULTS

The estimated average bilirubin level was 8.8 micromol/L (0.51 mg/dL). Atazanavir increased bilirubin levels by 15 mu mol/L (0.87 mg/dL), and indinavir increased bilirubin levels by 8 micromol/L (0.46 mg/dL). Ritonavir, lopinavir, saquinavir, and nelfinavir had no or minimal effect on bilirubin levels. Homozygous UGT1A1*28 increased bilirubin levels by 5.2 micromol/L (0.3 mg/dL). As a consequence, 67% of individuals homozygous for UGT1A1*28 and receiving atazanavir or indinavir had > or =2 episodes of hyperbilirubinemia in the jaundice range (>43 micromol/L [>2.5 mg/dL]), versus 7% of those with the common allele and not receiving either of those protease inhibitors (P<.001). Efavirenz resulted in decreased bilirubin levels, which is consistent with the induction of UDP-glucuronosyltransferase 1A1.

CONCLUSIONS

Genotyping for UGT1A1*28 before initiation of ART would identify HIV-infected individuals at risk for hyperbilirubinemia and decrease episodes of jaundice.

Therapeutic lentivirus-mediated neonatal in vivo gene therapy in hyperbilirubinemic Gunn rats

Crigler-Najjar type 1 disease (CN-1) is a genetic disorder characterized by high levels of unconjugated bilirubin due to the absence of hepatic UDPglucuronosyltransferase (UGT1) activity. Here we show that in vivo neonatal hepatocyte transduction with a lentiviral vector expressing the defective enzyme resulted in long-term correction in Gunn rats, a model of CN-1. Lentiviral vectors harboring the human UGT1 cDNA (approved symbol UGT1A1) under the control of a liver-specific transthyretin promoter were produced. Two-day-old Gunn rats were injected with 50 microl of vector. Bilirubinemia was monitored at 6 weeks and monthly thereafter. At 6 weeks, bilirubinemia was completely normalized in treated animals, whereas it remained around 100 microM in control rats. The level of correction remained stable for up to 42 weeks. Large amounts of bilirubin conjugates were present in the bile of corrected animals. PCR and Western blots confirmed the presence and expression of UGT1 in liver. The estimated proportion of transduced hepatocytes was 40% and transduced cells were not detected in extrahepatic tissues except bone marrow in some animals. This work represents the first demonstration of a complete and permanent correction of hyperbilirubinemia in Gunn rats using lentiviral vectors.

Regulation of hyaluronan synthase-2 expression in human intestinal mesenchymal cells: mechanisms of interleukin-1beta-mediated induction

Elevated levels of hyaluronan are associated with numerous inflammatory diseases including inflammatory bowel disease. The purpose of this study was to determine whether a cause and effect relationship might exist among proinflammatory cytokines, IL-1beta, TNF-alpha, IFN-gamma, or transforming growth factor-beta (TGF-beta) and hyaluronan expression in human JDMC and, if so, to identify possible mechanisms involved in the induction of hyaluronan expression. TGF-beta, TNF-alpha, and IFN-gamma had little or no effect on hyaluronan production by these cells. Treatment with IL-1beta induced an approximate 30-fold increase in the levels of hyaluronan in the medium of human jejunum-derived mesenchymal cells. Ribonuclease protection analysis revealed that steady-state transcript levels for hyaluronan synthase (HAS)2 were present at very low levels in untreated cells but increased as much as 18-fold in the presence of IL-1beta. HAS3 transcript levels were also increased slightly by exposure of these cells to IL-1beta. Expression of HAS1 transcripts was not detected under any condition in these cells. IL-1beta induction of hyaluronan expression was inhibited in cells transfected with short interfering RNA corresponding to HAS2 transcripts. Inhibitors of the p38 and ERK1/2 mitogen-activated pathways but not JNK/SAPK blocked the IL-1beta-mediated induction of hyaluronan expression and the increase in HAS2 transcript expression. These results suggest that IL-1beta induction of HAS2 expression involves multiple signaling pathways that act in concert, thus leading to an increase in expression of hyaluronan by jejunum-derived mesenchymal cells.

Hyaluronan Synthases, Hyaluronan and Its CD44 Receptors in the Posterior Segment of Rabbit Eye

To understand the possible roles of the hyaluronan synthetase (HAS)/hyaluronan (HA)/CD44 signaling system in the posterior eye segment, we investigated the expression of rabbit HAS isoforms and CD44 mRNA by RT-PCR and the level of HA by using HA assay and immunohistochemistry. HA was detectable in vitreous, retina and choroid. The expression of three HAS isoforms was clearly detected in both retina and choroids. Rabbit choroid showed a significant increase of the HAS2 and HAS3 expression compared with rabbit retina (HAS2 p = 0.0014 < 0.05; HAS3 p = 0.0006 < 0.05). Similarly, mRNA expression of CD44 was detected in both retina and choroids. This evidence may suggest that the HAS/HA/CD44 signaling system is important in maintaining the functional structure of retina and choroid.

[Correlation of polymorphisms of UDP-glucuronosyltransferase 1A7 gene to genetic susceptibility of lung cancer]

BACKGROUND & OBJECTIVE

UDP-glucuronosyltransferase 1A7 (UGT1A7) plays an important role in detoxification through catalyzing combination of glucuronic acid and tobacco carcinogens, including benzo [alpha] pyrene, nitrosamine, and heterocyclic amine PhIP, therefore, inactivates the carcinogens. This study was to examine the correlation of polymorphisms of UGT1A7 gene to genetic susceptibility of lung cancer.

METHODS

Polymorphisms of UGT1A7 gene at 12-131 and 208 sites in peripheral lymph cells of 312 patients and 317 age- and sex-matched controls were detected by polymerase chain reaction-denaturized high performance liquid chromatography (PCR-DHPLC) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP); the correlation of these polymorphisms to genetic susceptibility of lung cancer was analyzed.

RESULTS

Compared with the UGT1A7*1/*1 genotype carriers, the UGT1A7*3/*1 genotype carriers had a 1.80-fold increased risk of lung adenocarcinoma [adjusted odds ratio (OR), 1.80; 95% confidence interval (CI), 1.03-3.12], the UGT1A7*3 genotype carriers had a 1.59-fold increased risk of lung adenocarcinoma (adjusted OR, 1.59; 95% CI, 0.96-2.63). The UGT1A7 polymorphisms had no correlation with risk of lung squamous cell carcinoma.

CONCLUSION

UGT1A7 gene polymorphisms may increase the genetic susceptibility of lung adenocarcinoma in Chinese.