Nevirapine restores hormone sensitivity in undifferentiated androgen-refractory prostate carcinoma cells

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Background: The majority of prostate carcinomas are hormone-dependent tumors and androgen deprivation is the mainstay of therapy for advanced prostate cancer. However, androgen deprivation is ineffective on intermediate androgen-independent cells that are responsible for the hormone-refractory prostate cancer progression. Furthermore, other signaling pathways - i.e. EGF - can provide additional molecular mechanisms contributing to androgen-independent tumor progression. Reverse transcriptase (RT) inhibitors represent differentiating agents able to induce a reprogramming of gene expression in several human tumor cell models. Indeed, nevirapine and efavirenz, two widely used RT inhibitors, block the activity of endogenous RT, a gene highly expressed in tumor cells. Methods: We evaluated the ability of nevirapine to antagonize tumor growth and induce hormone sensitivity in androgen-independent human prostate tumor PC-3 cells either in vitro or in vivo. Results: Nevirapine induced the expression of several molecular markers of an androgen-dependent phenotype, such androgen receptor (AR), PSA and K18 and a reduced expression of K5, a marker of the intermediate-cell phenotype. Indeed, nevirapine enhanced the ability of prostate tumor cells to up-regulate AR in response to dihidrotestosterone. Moreover, the pharmacological inhibition of RT resulted in a significant reprogramming of gene expression, characterized by down-regulation of the notch family receptors, the EGFR1, the VEGF receptor KDR, the FGF family receptors, as well as the angiogenic factors VEGF and FGF1. Interestingly, this exocrine differentiated phenotype correlated with a reversible inhibition of cell proliferation and migration in response to nevirapine. Furthermore, the treatment of mice xenografts of prostate carcinoma cells with efavirenz and nevirapine resulted in the inhibition of tumor growth and in a reduced tumorigenic potential of cells. Conclusions: These findings suggest that RT inhibition is able to convert the androgen-independent intermediate-cell phenotype into an androgen-dependent exocrine luminal phenotype and support the need for clinical trials to test the ability of RT inhibitors and LH-RH analogs in androgen-independent prostate tumors.

No significant financial relationships to disclose.

Spectrum ofUGT1A1 mutations in Crigler-Najjar (CN) syndrome patients: identification of twelve novel alleles and genotype-phenotype correlation

Crigler-Najjar syndrome types I and II (CN1 and CN2) are usually inherited as autosomal recessive conditions and are characterized by non-hemolytic unconjugated hyperbilirubinaemia. CN1 is the most severe form, associated with the absence of hepatic bilirubin-uridinediphosphoglucuronate glucuronosyltransferase (UGT1A1) activity. CN2 presents intermediate levels of hyperbilirubinaemia as a result of an incomplete deficiency of hepatic UGT1A1 activity. Here, we present the analysis of UGT1A1 gene in 31 unrelated Crigler-Najjar (CN) syndrome patients. This analysis allowed us to identify 22 mutations, 12 of which were not previously described, expanding the spectrum of known UGT1 mutations to 77. Novel mutations, considered pathogenic, including one nonsense mutation, two altered splice sites, one single base deletion and nine missense mutations were identified in coding exons of the UGT1A1gene and flanking introns. Several novel missense mutations localize in critical domain of UGT1A1 enzyme. In addition, the evaluation of Gilbert-type promoter of UGT1A1in Crigler-Najjar (CN) syndrome patients was performed. The polymorphisms of the promoter region can modify the UGT1A1 mutation phenotype. This study represents the molecular characterization of the largest cohort of Italian Crigler-Najjar Gilbert syndrome patients studied so far; increase the mutational spectrum of UGT1A1 allelic variants worldwide and provide a new insight useful for clinical diagnosis and genetic counseling.

Genes transcriptionally modulated by interferon alpha2a correlate with the cytokine activity

BACKGROUND AND OBJECTIVES

Interferon alpha2a (IFNalpha2a) mediates important antiviral, antiproliferative and immunomodulatory responses and is employed in the treatment of human diseases, including chronic myelogenous leukemia. Here, we report the IFNalpha2a-dependent expression profiles of three malignant cell lines derived from liver, lymphocytes and muscle.

DESIGN AND METHODS

The experiments were performed in the presence of cycloheximide, thus our results exclusively reflect direct transcriptional modulation. The short exposure time i.e. 5 hours evidences only the early events, excluding the effects of complex phenotypic changes on the expression.

RESULTS

Our findings indicate that IFNalpha2a rapidly up-regulates the expression of STAT1, STAT2 and ISGF3G genes. This activity should result in the amplification of the cellular response to the cytokine. Moreover, IFNalpha2a directly modulates the expression of: (i) important transcriptional factors, e.g. IRF1 and IRF7 which control pivotal cellular events, and (ii) enzymes involved in the IFNalpha2a-dependent antiviral and apoptotic response. Interestingly, we showed that the cytokine induces transcriptional expression of Sjögren's syndrome antigen A1, a protein involved in several autoimmune diseases.

INTERPRETATION AND CONCLUSIONS

The observed changes induced by IFNalpha2a could be related to the development of autoimmune syndromes observed during IFNalpha2a treatment. A number of genes transcriptionally regulated by the cytokine have been identified for the first time; these might represent additional effectors of IFNalpha2a activity.

Reelin gene alleles and haplotypes as a factor predisposing to autistic disorder

Autistic disorder (MIM 209850) is currently viewed as a neurodevelopmental disease. Reelin plays a pivotal role in the development of laminar structures including the cerebral cortex, hippocampus, cerebellum and of several brainstem nuclei. Neuroanatomical evidence is consistent with Reelin involvement in autistic disorder. In this study, we describe several polymorphisms identified using RNA-SSCP and DNA sequencing. Association and linkage were assessed comparing 95 Italian patients to 186 ethnically-matched controls, and using the transmission/disequilibrium test and haplotype-based haplotype relative risk in 172 complete trios from 165 families collected in Italy and in the USA. Both case-control and family-based analyses yield a significant association between autistic disorder and a polymorphic GGC repeat located immediately 5' of the reelin gene (RELN) ATG initiator codon, as well as with specific haplotypes formed by this polymorphism with two single-base substitutions located in a splice junction in exon 6 and within exon 50. Triplet repeats located in 5' untranslated regions (5'UTRs) are indicative of strong transcriptional regulation. Our findings suggest that longer triplet repeats in the 5'UTR of the RELN gene confer vulnerability to autistic disorder.

Transforming growth factor-beta1 gene polymorphism, bone turnover, and bone mass in Italian postmenopausal women

Transforming growth factor beta1 (TGF-beta1) is abundant in bone and is an important regulator of the osteoclastic-osteoblastic interaction (coupling). The sequence variation, 713-8delC in the TGF-beta1 gene has previously been found to be associated with very low bone mass in osteoporotic women and with increased bone turnover in both osteoporotic and normal women. The possible association of this polymorphism with bone mass and bone turnover has now been investigated in 256 postmenopausal Italian women. A significant association of TGF-beta1 with bone mass was detected in the populations. Subjects carrying the sequence variation 713-8delC (Tt) genotype showed a significantly lower bone mineral density (BMD) at the hip than those without sequence variation in the genotype (TT). Individuals carrying the tt genotype have a more severe osteoporosis (P=0.0001 vs. TT and Tt genotypes). The frequency of the fragility fractures was significantly lower in individuals with TT genotype than in those with the Tt and tt genotypes (X2=21.9; P=0.006). Furthermore a significant association was found between 713-8delC and bone turnover. The results suggest a strong evidence for an association among the 713-8delC allele of the TGF-beta1 gene and the femoral BMD, the prevalence of osteoporotic fractures, and finally a high bone turnover in a sample of Italian postmenopausal women.