Benazepril conferred substantial renal benefits in patients without diabetes who had advanced renal insufficiency. (ClinicalTrials.gov number, NCT00270426.)

Despite advances in characterizing the pathophysiology and genetics of pituitary tumors, molecular mechanisms of their pathogenesis are poorly understood. Recently, we isolated a transforming gene [pituitary tumor-transforming gene (PTTG)] from rat pituitary tumor cells. Here we describe the cloning of human PTTG, which is located on chromosome 5q33 and shares striking sequence homology with its rat counterpart. Northern analysis revealed PTTG expression in normal adult testis, thymus, colon, small intestine, brain, lung, and fetal liver, but most abundant levels of PTTG mRNA were observed in several carcinoma cell lines. Stable transfection of NIH 3T3 cells with human PTTG cDNA caused anchorage-independent transformation in vitro and induced in vivo tumor formation when transfectants were injected into athymic mice. Overexpression of PTTG in transfected NIH 3T3 cells also stimulated expression and secretion of basic fibroblast growth factor, a human pituitary tumor growth-regulating factor. A proline-rich region, which contains two PXXP motifs for the SH3 domain-binding site, was detected in the PTTG protein sequence. When these proline residues were changed by site-directed mutagenesis, PTTG in vitro transforming and in vivo tumor-inducing activity, as well as stimulation of basic fibroblast growth factor, was abrogated. These results indicate that human PTTG, a novel oncogene, may function through SH3-mediated signal transduction pathways and activation of growth factor(s).

Maternally expressed gene 3 (MEG3) is an imprinted gene highly expressed in the human pituitary. However, MEG3 expression is lost in human gonadotroph-derived pituitary adenomas and most human tumor cell lines. Expression of MEG3 in tumor cells results in growth suppression, p53 protein increase, and activation of p53 downstream targets. The MEG3 gene encodes a noncoding RNA of approximately 1700 nucleotides. There are 12 different MEG3 gene transcripts, generated by alternative splicing. They contain the common exons 1-3 and exons 8-10, but each uses one or more exons 4-7 in a different combination in the middle. MEG3 isoform expression patterns are tissue and cell type specific. Functionally, each isoform stimulates p53-mediated transactivation and suppresses tumor cell growth. We analyzed the secondary RNA folding structure of each MEG3 isoform, using the computer program mfold. All MEG3 RNA isoforms contain three distinct secondary folding motifs M1, M2, and M3. Deletion analysis showed that motifs M2 and M3 are important for p53 activation. Furthermore, a hybrid MEG3 RNA, containing a piece of artificially synthesized sequence different from the wild type but folding into a similar secondary structure, retained the functions of both p53 activation and growth suppression. These results support the hypothesis that a proper folding structure of the MEG3 RNA molecule is critical for its biological functions. This study establishes for the first time the structure-function relationship of a large noncoding RNA and provides a first look into the molecular mechanisms of the biological functions of a large noncoding RNA.

SUMMARYThe Dlk1-Gtl2 imprinting locus is located on mouse distal chromosome 12 and consists of multiple maternally expressed noncoding RNAs and several paternally expressed protein-coding genes. The imprinting of this locus plays a crucial role in embryonic development and postnatal growth. At least one cis-element, the intergenic differentially methylated region (IG-DMR) is required for expression of maternally expressed genes and repression of silenced paternally expressed genes. The mechanism by which the IG-DMR functions is largely unknown. However, it has been suggested that the unmethylated IG-DMR acts as a positive regulator activating expression of non-coding RNAs. Gtl2 is the first non-coding RNA gene downstream of the IG-DMR. Although its in vivo function in the mouse is largely unknown, its human ortholog MEG3 has been linked to tumor suppression in human tumorderived cell lines. We generated a knockout mouse model, in which the first five exons and adjacent promoter region of the Gtl2 gene were deleted. Maternal deletion of Gtl2 resulted in perinatal death and skeletal muscle defects, indicating that Gtl2 plays an important role in embryonic development. The maternal deletion also completely abolished expression of downstream maternally expressed genes, activated expression of silenced paternally expressed genes and resulted in methylation of the IG-DMR. By contrast, the paternal inherited deletion did not have this effect. These data strongly indicate that activation of Gtl2 and its downstream maternal genes play an essential role in regulating Dlk1-Gtl2 imprinting, possibly by maintaining active status of the IG-DMR.

DLK1-MEG3is an imprinted locus consisting of multiple maternally expressed noncoding RNA genes and paternally expressed protein-coding genes. The expression of maternally expressed gene 3 (MEG3) is selectively lost in clinically nonfunctioning adenomas (NFAs) of gonadotroph origin; however, expression status of other genes at this locus in human pituitary adenomas has not previously been reported. Using quantitative real-time RT-PCR, we evaluated expression of 24 genes from the DLK1-MEG3 locus in 44 human pituitary adenomas (25 NFAs, 7 ACTH-secreting, 7 GH-secreting, and 5 PRL-secreting adenomas) and 10 normal pituitaries. The effects on cell proliferation of five miRNAs whose expression was lost in NFAs were investigated by flow cytometry analysis. We found that 18 genes, including 13 miRNAs at the DLK1-MEG3 locus, were significantly down-regulated in human NFAs. In ACTH-secreting and PRL-secreting adenomas, 12 and 7 genes were significantly downregulated, respectively; no genes were significantly down-regulated in GH-secreting tumors. One of the five miRNAs tested induced cell cycle arrest at the G2/M phase in PDFS cells derived from a human NFA. Our data indicate that the DLK1-MEG3 locus is silenced in NFAs. The growth suppression by miRNAs in PDFS cells is consistent with the hypothesis that the DLK1-MEG3 locus plays a tumor suppressor role in human NFAs.

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This phase II/III, double-blind, randomized trial assessed the efficacy, immunogenicity and safety of the human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine in young Chinese women (ClinicalTrials.gov registration NCT00779766). Women aged 18–25 years from Jiangsu province were randomized (1:1) to receive HPV vaccine (n = 3,026) or Al(OH)3 control (n = 3,025) at months 0, 1 and 6. The primary objective was vaccine efficacy (VE) against HPV-16/18 associated 6-month persistent infection (PI) and/or cervical intraepithelial neoplasia (CIN) 1+. Secondary objectives were VE against virological and clinical endpoints associated with HPV-16/18 and with high-risk HPV types, immunogenicity and safety. Mean follow-up for the according-to-protocol cohort for efficacy (ATP-E) was ∼15 months after the third dose. In the ATP-E (vaccine = 2,889; control = 2,894), for initially HPV DNA negative and seronegative subjects, HPV-16/18 related VE (95% CI) was 94.2% (62.7, 99.9) against 6-month PI and/or CIN1+ and 93.8% (60.2, 99.9) against cytological abnormalities. VE against HPV-16/18 associated CIN1+ and CIN2+ was 100% (−50.4, 100) and 100% (−140.2, 100), respectively (no cases in the vaccine group and 4 CIN1+ and 3 CIN2+ cases in the control group). At Month 7, at least 99.7% of initially seronegative vaccine recipients had seroconverted for HPV-16/18; geometric mean antibody titres (95% CI) were 6,996 (6,212 to 7,880) EU/mL for anti-HPV-16 and 3,309 (2,942 to 3,723) EU/mL for anti-HPV-18. Safety outcomes between groups were generally similar. The HPV-16/18 AS04-adjuvanted vaccine is effective, immunogenic and has a clinically acceptable safety profile in young Chinese women. Prophylactic HPV vaccination has the potential to substantially reduce the burden of cervical cancer in China.What's New?With an estimated 75,000 new cases and 34,000 women dying from the disease annually, cervical cancer is a major public-health concern in China. This is the first large scale randomised clinical trial of a human papillomavirus (HPV) vaccine in China. The vaccine was found to be effective, immunogenic, and to have a clinically acceptable safety profile in young Chinese women. Prophylactic HPV vaccination thus has the potential to substantially reduce the burden of cervical cancers and precancers in China.

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