Marco Ciotti

Genetic polymorphism in the human UGT1A6 (planar phenol) UDP-glucuronosyltransferase: pharmacological implications.

Two missense mutations were uncovered in the UGT1A6 (HLUG P1) cDNA which codes for a human phenol-metabolizing UDP-glucuronosyltransferase. The mutant and a wild-type UGT1A6 cDNAs were isolated from a custom synthesized human liver lambda Zap cDNA library. Both an A to G transition at nucleotide 541 (T181 A) and an A to C transversion at nucleotide 552 (R184S) occurred in exon 1 of the UGT1A6 (UGT1F) gene at the UGT1 locus. The two mutations on a single allele created a heterozygous genotype. Newly created BsmI and BsoFI sites at the T181 A and R184S locations, respectively, were confirmed by endonuclease treatment of PCR-generated DNA using the donor-liver genomic DNA as template. Screens with endonuclease treatment showed that 33/98 DNA samples were heterozygous with both mutations on one allele. One other individual also carried the R184S mutation on the second allele. Wild-type UGT1A6 generated a broad plateau of activity from pH 5.0 to pH 8.0 with certain experimental phenols, while activity was 1.3-2.5-fold higher at pH 6.4 than at pH 7.2 for others. UGT1A6*2 (181 A+ and 184S+) metabolized 4-nitrophenol, 4-tert-butylphenol, 3-ethylphenol/4-ethylphenol, 4-hydroxycoumarin, butylated hydroxy anisole and butylated hydroxy toluene, with the pH 6.4 preference, at only 27-75% of the rate of the wild-type isozyme whereas 1-naphthol, 3-iodophenol, 7-hydroxycoumarin, and 7-hydroxy-4-methylcoumarin were metabolized at essentially the normal level. Furthermore, UGT1A6*2 metabolized 3-O-methyl-dopa and methyl salicylate at 41-74% of that of the wild-type, and a series of beta-blockers at 28-69% of the normal level. This evidence suggests that the UGT1A6 enzyme activity is affected by different amino acids depending upon the substrate selection.

TP53 codon 72 polymorphism and cervical cancer: a pooled analysis of individual data from 49 studies.

BACKGROUND Cervical cancer is caused primarily by human papillomaviruses (HPV). The polymorphism rs1042522 at codon 72 of the TP53 tumour-suppressor gene has been investigated as a genetic cofactor. More than 80 studies were done between 1998 and 2006, after it was initially reported that women who are homozygous for the arginine allele had a risk for cervical cancer seven times higher than women who were heterozygous for the allele. However, results have been inconsistent. Here we analyse pooled data from 49 studies to determine whether there is an association between TP53 codon 72 polymorphism and cervical cancer. METHODS Individual data on 7946 cases and 7888 controls from 49 different studies worldwide were reanalysed. Odds ratios (OR) were estimated using logistic regression, stratifying by study and ethnic origin. Subgroup analyses were done for infection with HPV, ethnic origin, Hardy-Weinberg equilibrium, study quality, and the material used to determine TP53 genotype. FINDINGS The pooled estimates (OR) for invasive cervical cancer were 1.22 (95% CI 1.08-1.39) for arginine homozygotes compared with heterozygotes, and 1.13 (0.94-1.35) for arginine homozygotes versus proline homozygotes. Subgroup analyses showed significant excess risks only in studies where controls were not in Hardy-Weinberg equilibrium (1.71 [1.21-2.42] for arginine homozygotes compared with heterozygotes), in non-epidemiological studies (1.35 [1.15-1.58] for arginine homozygotes compared with heterozygotes), and in studies where TP53 genotype was determined from tumour tissue (1.39 [1.13-1.73] for arginine homozygotes compared with heterozygotes). Null results were noted in studies with sound epidemiological design and conduct (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes), and studies in which TP53 genotype was determined from white blood cells (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes). INTERPRETATION Subgroup analyses indicated that excess risks were most likely not due to clinical or biological factors, but to errors in study methods. No association was found between cervical cancer and TP53 codon 72 polymorphism when the analysis was restricted to methodologically sound studies. FUNDING German Research Foundation (DFG).

p16INK4A expression is related to grade of CIN and high-risk human papillomavirus but does not predict virus clearance after conization or disease outcome

The role of p16INK4a as a marker of HR-HPV and in the diagnosis of CIN has been well established, but its predictive value in the clearance of the virus after CIN treatment and its use as a prognostic marker of cervical cancer has not been studied. A series of 302 archival samples, including 150 squamous cell carcinomas (SCCs) and 152 CIN lesions, were subjected to immunohistochemical staining for p16INK4a and HPV testing using PCR with three primer sets (MY09/11, GP5+/GP6+, SPF). Follow-up data were available of 88 SCC patients, and 67 of the CIN lesions had been followed-up with serial PCR after conization. HR-HPV types were closely associated with CIN (OR 19.12; 95%CI 2.31–157.81) and SCC (OR 27.25; 95%CI 3.28–226.09). There was a significant linear relationship between the lesion grade and intensity of p16INK4a staining (p = 0.0001). The expression of p16INK4a was also closely related to HR-HPV (p = 0.0001). p16INK4a staining was a 100% specific indicator of CIN, with 100% PPV, and showed 83.5% sensitivity and 80.1% PPV in detecting HR-HPV. However, p16INK4a staining did not predict clearance/persistence of HR-HPV after treatment of CIN. Similarly, despite a slightly more favorable survival in women with strong/intense p16INK4a staining in univariate analysis, p16INK4a expression was not an independent prognostic predictor in multivariate survival (Cox) analysis. After adjustment for p16INK4a staining, HR-HPV, histological grade, International Federation of Gynecology and Obstetrics (FIGO) stage, and age, only the last two were significant prognostic predictors (p = 0.0001 and p = 0.003, respectively). The present data confirm the role of p16INK4a as a highly specific marker of CIN and HR-HPV type, but expression of this protein does not seem to be of any prognostic value in cervical cancer or in predicting the clearance of HR-HPV after treatment of CIN. We speculate that different subgroups of cervical cancer are characterized by aberrant p16INK4a/cyclin D/Rb pathways that are due to different mechanisms that can be mutually exclusive.

HCV Genotypes Are Differently Prone to the Development of Resistance to Linear and Macrocyclic Protease Inhibitors

Background Because of the extreme genetic variability of hepatitis C virus (HCV), we analyzed whether specific HCV-genotypes are differently prone to develop resistance to linear and macrocyclic protease-inhibitors (PIs). Methods The study includes 1568 NS3-protease sequences, isolated from PI-naive patients infected with HCV-genotypes 1a (N = 621), 1b (N = 474), 2 (N = 72), 3 (N = 268), 4 (N = 54) 5 (N = 6), and 6 (N = 73). Genetic-barrier was calculated as the sum of nucleotide-transitions (score = 1) and/or nucleotide-transversions (score = 2.5) required for drug-resistance-mutations emergence. Forty-three mutations associated with PIs-resistance were analyzed (36A/M/L/G-41R-43S/V-54A/S/V-55A-Q80K/R/L/H/G-109K-138T-155K/Q/T/I/M/S/G/L-156T/V/G/S-158I-168A/H/T/V/E/I/G/N/Y-170A/T-175L). Structural analyses on NS3-protease and on putative RNA-models have been also performed. Results Overall, NS3-protease was moderately conserved, with 85/181 (47.0%) amino-acids showing <1% variability. The catalytic-triad (H57-D81-S139) and 6/13 resistance-associated positions (Q41-F43-R109-R155-A156-V158) were fully conserved (variability <1%). Structural-analysis highlighted that most of the NS3-residues involved in drug-stabilization were highly conserved, while 7 PI-resistance residues, together with selected residues located in proximity of the PI-binding pocket, were highly variable among HCV-genotypes. Four resistance-mutations (80K/G-36L-175L) were found as natural polymorphisms in selected genotypes (80K present in 41.6% HCV-1a, 100% of HCV-5 and 20.6% HCV-6; 80G present in 94.4% HCV-2; 36L present in 100% HCV-3-5 and >94% HCV-2-4; 175L present in 100% HCV-1a-3-5 and >97% HCV-2-4). Furthermore, HCV-3 specifically showed non-conservative polymorphisms (R123T-D168Q) at two drug-interacting positions. Regardless of HCV-genotype, 13 PIs resistance-mutations were associated with low genetic-barrier, requiring only 1 nucleotide-substitution (41R-43S/V-54A-55A-80R-156V/T: score = 1; 54S-138T-156S/G-168E/H: score = 2.5). By contrast, by using HCV-1b as reference genotype, nucleotide-heterogeneity led to a lower genetic-barrier for the development of some drug-resistance-mutations in HCV-1a (36M-155G/I/K/M/S/T-170T), HCV-2 (36M-80K-155G/I/K/S/T-170T), HCV-3 (155G/I/K/M/S/T-170T), HCV-4-6 (155I/S/L), and HCV-5 (80G-155G/I/K/M/S/T). Conclusions The high degree of HCV genetic variability makes HCV-genotypes, and even subtypes, differently prone to the development of PIs resistance-mutations. Overall, this can account for different responsiveness of HCV-genotypes to PIs, with important clinical implications in tailoring individualized and appropriate regimens.

Survivin as a Marker of Cervical Intraepithelial Neoplasia and High-Risk Human Papillomavirus and a Predictor of Virus Clearance and Prognosis in Cervical Cancer

We analyzed survivin as a marker of cervical intraepithelial neoplasia (CIN) and high-risk human papillomavirus (HR-HPV) and a predictor of HPV clearance and disease outcome in cervical cancer in 302 samples (squamous cell carcinomas [SCCs], 150; CIN lesions, 152) by immunohistochemical staining with survivin antibody and HPV testing using polymerase chain reaction. HR-HPV types were associated closely with CIN and SCC. There was a significant linear relationship between grade and intensity of survivin expression (P = .0001). Survivin overexpression also was associated strongly with HR-HPV type (P = .0001). Multivariate regression analysis revealed survivin and p16(INK4a) as equally strong independent predictors of HR-HPV. Deregulated survivin expression did not predict clearance or persistence of HR-HPV after treatment of CIN or survival in cervical cancer in univariate (P = .417) or multivariate analysis. After adjustment for HR-HPV, stage, age, and tumor grade in the Cox regression model, only stage (P = .0001) and age (P = .0001) remained independent prognostic predictors. Survivin seems to be an early marker of cervical carcinogenesis. Up-regulated survivin expression was an independent predictor of HR-HPV in cervical lesions, most plausibly explained by its normal transcriptional repression by wild-type p53 being eliminated by HR-HPV E6 oncoprotein.

Safety of complete and sustained prophylaxis withdrawal in patients liver-transplanted for HBV-related cirrhosis at low risk of HBV recurrence

BACKGROUND & AIMS HBV reactivation after liver transplantation may be related to persistence of covalently closed circular (ccc) DNA. We investigated the safety of HBV prophylaxis withdrawal in selected HBV transplanted patients. METHODS Thirty patients transplanted 64-195months earlier (23 males, median age 56yrs), HBsAg-positive, HBeAg, and HBV-DNA negative at transplant (43% HCV/HDV co-infected), with undetectable intrahepatic total and ccc-DNA were enrolled. All patients underwent HBIg withdrawal and continued lamivudine with monthly HBsAg and HBV-DNA monitoring and sequential liver biopsies. Those with confirmed intrahepatic total and ccc-DNA undetectability 24weeks after stopping HBIg, also underwent lamivudine withdrawal and were followed-up without prophylaxis. RESULTS Twenty-five patients did not exhibit signs of HBV recurrence after prophylaxis withdrawal (median follow-up 28.7months, range 22-42). Five patients became HBsAg-positive: one early after HBIg withdrawal, the other four after HBIG and lamivudine withdrawal. None of these patients experienced clinically relevant events. In the first patient, HBIg were reinstituted with prompt HBsAg negativization. Of the other four, one remained HBsAg-positive with detectable HBV-DNA and mild ALT elevation and was successfully treated with tenofovir. In the remaining three, HBsAg positivity was transient and followed by anti-HBs seroconversion, thus no antiviral treatment was needed. CONCLUSIONS Patients with undetectable HBV viremia at transplant and no evidence of intrahepatic total and cccDNA may safely undergo cautious weaning of prophylaxis, showing low rate of HBV recurrence after a 2 year follow-up. Undetectability of intrahepatic ccc-DNA may help to identify patients at low-risk of recurrence, yet studies with longer follow-up are needed.

Identification of Merkel cell polyomavirus in the lower respiratory tract of Italian patients.

Merkel cell polyomavirus (MCPyV) has been found to be integrated monoclonally in a rare skin cancer named Merkel cell carcinoma. More recently, MCPyV has been detected in the upper respiratory tract of pediatric and adult patients. However, the mode of transmission and pathogenic role of MCPyV in the respiratory system has not been determined. In this study, MCPyV was sought in the lower respiratory tract of adult patients admitted to the hospital. MCPyV DNA was detected in 15 (17.24%) out of 87 lower respiratory tract samples. Most of the patients with MCPyV were over 50 years old. Nucleotide sequence of the t‐antigen of MCPyV identified in respiratory secretions showed a homology to those found in Merkel cell carcinoma. In addition, phylogenetic analysis undertaken on the t‐antigen sequences of Italian isolates and other MCPyVs identified in healthy and cancer tissues showed that all these isolates belonged to the same clade. Selective pressure analysis for the t‐antigen revealed the presence of five sites under positive selection (ω = 4.3), with a posterior probabilities above 0.99. The α parameter of the gamma distribution was 0.01, showing that this distribution has a characteristic L‐shape and suggesting a strong nucleotide substitution rate heterogeneity across sites. This study shows that MCPyV can infect the lower respiratory tract, but further investigations are needed to define its pathogenic role in respiratory diseases. J. Med. Virol. 82:505–509, 2010.

Gastrointestinally Distributed UDP-glucuronosyltransferase 1A10, Which Metabolizes Estrogens and Nonsteroidal Anti-inflammatory Drugs, Depends upon Phosphorylation*

Among gastrointestinal distributed isozymes encoded at the UGT1 locus, UDP-glucuronosyltransferase 1A10 (UGT1A10) metabolizes a number of important chemicals. Similar to broad conversion of phytoestrogens (Basu, N. K., Ciotti, M., Hwang, M. S., Kole, L., Mitra, P. S., Cho, J. W., and Owens, I. S. (2004) J. Biol. Chem. 279, 1429–1441), UGT1A10 metabolized estrogens and their derivatives, whereas UGT1A1, -1A3, -1A7, and -1A8 differentially exhibited reduced activity toward the same. UGT1A10 compared with UGT1A7, -1A8, and -1A3 generally exhibited high activity toward acidic nonsteroidal anti-inflammatory drugs and natural benzaldehyde derivatives, while UGT1A3 metabolized most efficiently aromatic transcinnamic acids known to be generated from flavonoid glycosides by microflora in the lower gastrointestinal tract. Finally UGT1A10, -1A7, -1A8, and -1A3 converted plant-based salicylic acids; methylsalicylic acid was transformed at high levels, and acetylsalicylic (aspirin) and salicylic acid were transformed at moderate to low levels. Atypically UGT1A10 transformed estrogens between pH 6 and 8 but acidic structures preferentially at pH 6.4. Furthermore evidence indicates UGT1A10 expressed in COS-1 cells depends upon phosphorylation; UGT1A10 versus its single, double, and triple mutants at three predicted protein kinase C phosphorylation sites incorporated [33P]-orthophosphate and showed a progressive decrease with no detectable label or activity for the triple T73A/T202A/S432G-1A10 mutant. Single and double mutants revealed either null/full activity or null/additive activity, respectively. Additionally UGT1A10-expressing cultures glucuronidated 17β-[14C]estradiol, whereas cultures containing null mutants at protein kinase C sites showed no estrogen conversion. Importantly UGT1A10 in cells supported 10-fold higher glucuronidation of 17β-estradiol than UGT1A1. In summary, our results suggest gastrointestinally distributed UGT1A10 is important for detoxifying estrogens/phytoestrogens and aromatic acids with complementary activity by UGT1A7, -1A8, -1A3, and/or -1A1 evidently dependent upon phosphorylation.

Activation of the ERK/MAP kinase pathway in cervical intraepithelial neoplasia is related to grade of the lesion but not to high-risk human papillomavirus, virus clearance, or prognosis in cervical cancer.

We subjected 302 archival samples (150 squamous cell carcinomas [SCCs] and 152 cervical intraepithelial neoplasia [CIN] lesions) to immunohistochemical staining with extracellular signal-regulated kinase-1 (ERK1) antibody and human papillomavirus (HPV) testing with 3 primer sets. Follow-up data were available for all SCC cases and 67 CIN cases. High-risk (HR) HPV types were associated with CIN (odds ratio [OR], 19.12; 95% confidence interval [CI], 2.31-157.81) and SCC (OR, 27.25; 95% CI, 3.28226.09). There was a significant linear relationship between lesion grade and ERK1 staining intensity (P = .0001). ERK1 staining was a 100% specific indicator of CIN, with a 100% positive predictive value, but a poor predictor of HR HPV. ERK1 expression did not predict clearance or persistence of HR HPV after CIN treatment. ERK1 staining did not significantly predict survival in cervical cancer in univariate (P = .915) or multivariate analysis. After adjustment for HR HPV, stage, age, and tumor grade in the Cox regression model, only stage (P = .0001) and age (P = .002) remained independent prognostic factors. ERK1 expression seems to be an early marker of cervical carcinogenesis. ERK1 overexpression is not a specific marker of HR-HPV in CIN and cervical cancer, nor does it predict virus clearance after CIN treatment or disease outcome in cervical cancer.

Excretion of the novel polyomaviruses KI and WU in the stool of patients with hematological disorders

Infection with human polyomaviruses BKV and JCV is asymptomatic, and lifelong and widespread, among the general population. However, in the setting of immunosuppression, secondary to medications or viral infection, for example, with HIV, reactivation can occur and result in severe disease. In this study, stool specimens from 31 patients with hematological disorders (25 transplanted and 6 non‐transplanted) were examined prospectively to determine whether the novel polyomaviruses KIV and WUV reactivated and were excreted in the gastrointestinal tract. Reactivation was correlated with the appearance of gastrointestinal and respiratory symptoms. Of the 31 patients examined, KIV and WUV were detected in 13 transplanted patients as single infection or in combination with BKV, cytomegalovirus (CMV), and adenovirus (Adv). Because of frequent co‐infections, a clear correlation between novel polyomaviruses and clinical symptoms could not be established. There was no correlation between demographic variables and detection of KIV and WUV. Phylogenetic analysis of the small t‐antigen gene of KIV and WUV isolates showed that the novel polyomaviruses identified in feces clustered with those identified in the respiratory tract suggesting an oral–fecal transmission of these viruses. The novel polyomaviruses KI and WU may have a pathogenic role in immunocompromised patients. J. Med. Virol. 81:1668–1673, 2009.