Failure to detect DNA in blastocoel fluid is associated with a higher live birth rate in both PGT-A and conventional IVF/ICSI cycles.

STUDY QUESTION: Is the presence of DNA in the blastocoel fluid (BF) of expanded blastocysts, assessed by whole genome amplification (WGA), associated with the clinical outcome at the first transfer? SUMMARY ANSWER: At the first transfer, blastocysts with negative BF-WGA have more chance to implant and to develop to term than those with positive BF-WGA results, both in preimplantation genetic testing for aneuploidies (PGT-A) cycles (where only euploid blastocysts resulting from the chromosomal analysis of trophectoderm (TE) biopsies were transferred) and in IVF/ICSI conventional cycles. WHAT IS KNOWN ALREADY: Retrospective studies conducted in patients undergoing PGT-A have shown that the incidence of negative BF-WGA was significantly higher in TE-euploid blastocysts than in TE-aneuploid blastocysts. In addition, after the transfer of TE-euploid blastocysts, the ongoing clinical pregnancy rate was significantly higher in the group with negative BF-WGA compared with those with positive BF-WGA. STUDY DESIGN, SIZE, DURATION: A prospective cohort study including 102 consecutive PGT-A patients (Group 1) and 88 consecutive conventional IVF/ICSI patients (Group 2), was conducted between January 2019 and December 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: In both groups, BFs were collected from expanded blastocysts of high grade and processed for WGA. DNA amplification was evaluated by agarose gel electrophoresis for the presence (positive BF-WGA) or absence (negative BF-WGA) of a band. Directly after the BF retrieval, blastocysts from Group 1 underwent TE biopsy and vitrification. In Group 2, blastocysts were vitrified immediately after BF collection. In Group 1, only euploid blastocysts were considered for transfer according to the results of TE biopsies. In both groups, the selection of the blastocyst to be transferred was based on BF-WGA results giving priority, if available, to those with negative amplification. The primary outcome investigated was the live birth rate (LBR) at the first transfer. The main variable under investigation was the negative BF-WGA and results were corrected for confounders (maternal and paternal age, number of retrieved oocytes, male factor) by multiple logistic regression analysis. MAIN RESULTS AND THE ROLE OF CHANCE: In Group 1, 60 patients transferred negative BF-WGA blastocysts and 42 positive BF-WGA blastocysts, and the LBR at the first transfer was 53.3% and 26.2%, respectively (P = 0.0081). After testing for selected confounders in a multiple logistic analysis, the transfer of blastocysts with negative BF-WGA resulted in an odds ratio of (OR) 3.52 (95% CI: 1.48-8.88, P = 0.0057) compared to transfer of positive BF-WGA blastocysts. In Group 2, at the first transfer 30 deliveries resulted from blastocysts with negative BF-WGA (48.4%) and three from the transfer of positive BF-WGA blastocysts in 26 patients (11.5%; P = 0.0014). Multiple logistic analysis indicated that the transfer of blastocysts with negative BF-WGA resulted in an OR 6.89 (95% CI: 1.98-32.95, P = 0.0056) compared to transfer of positive BF-WGA blastocysts. The LBR per transfer and the cumulative LBR per patient showed the same trend. LIMITATIONS, REASONS FOR CAUTION: The study was performed in a single center. WIDER IMPLICATIONS OF THE FINDINGS: The data from this study highlight the heterogeneity of blastocysts of similar morphology, even in those classified as euploid by TE analysis. Failure to detect DNA in BFs after WGA is associated with a significantly higher LBR at the first embryo transfer as well as per transfer and per patient. The processing of the BF by WGA is an easy and cost-effective tool that could become a valuable option to offer patients the highest chances of term pregnancy in the shortest time possible. STUDY FUNDING/COMPETING INTEREST(S): The study received no funding from external sources. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Aneuploidy in oocytes from women of advanced maternal age: analysis of the causal meiotic errors and impact on embryo development.

STUDY QUESTION: In oocytes of advanced maternal age (AMA) women, what are the mechanisms leading to aneuploidy and what is the association of aneuploidy with embryo development? SUMMARY ANSWER: Known chromosome segregation errors such as precocious separation of sister chromatids explained 90.4% of abnormal chromosome copy numbers in polar bodies (PBs), underlying impaired embryo development. WHAT IS KNOWN ALREADY: Meiotic chromosomal aneuploidies in oocytes correlate with AMA (>35 years) and can affect over half of oocytes in this age group. This underlies the rationale for PB biopsy as a form of early preimplantation genetic testing for aneuploidy (PGT-A), as performed in the 'ESHRE STudy into the Evaluation of oocyte Euploidy by Microarray analysis' (ESTEEM) randomized controlled trial (RCT). So far, chromosome analysis of oocytes and PBs has shown that precocious separation of sister chromatids (PSSC), Meiosis II (MII) non-disjunction (ND), and reverse segregation (RS) are the main mechanisms leading to aneuploidy in oocytes. STUDY DESIGN, SIZE, DURATION: Data were sourced from the ESTEEM study, a multicentre RCT from seven European centres to assess the clinical utility of PGT-A on PBs using array comparative genomic hybridization (aCGH) in patients of AMA (36-40 years). This included data on the chromosome complement in PB pairs (PGT-A group), and on embryo morphology in a subset of embryos, up to Day 6 post-insemination, from both the intervention (PB biopsy and PGT-A) and control groups. PARTICIPANTS/MATERIALS, SETTING, METHODS: ESTEEM recruited 396 AMA patients: 205 in the intervention group and 191 in the control group. Complete genetic data from 693 PB pairs were analysed. Additionally, the morphology from 1034 embryos generated from fertilized oocytes (two pronuclei) in the PB biopsy group and 1082 in the control group were used for statistical analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 461/693 PB pairs showed abnormal segregation in 1162/10 810 chromosomes. The main observed abnormal segregations were compatible with PSSC in Meiosis I (MI) (n = 568/1162; 48.9%), ND of chromatids in MII or RS (n = 417/1162; 35.9%), and less frequently ND in MI (n = 65/1162; 5.6%). For 112 chromosomes (112/1162; 9.6%), we observed a chromosome copy number in the first PB (PB1) and second PB (PB2) that is not explained by any of the known mechanisms causing aneuploidy in oocytes. We observed that embryos in the PGT-A arm of the RCT did not have a significantly different morphology between 2 and 6 days post-insemination compared to the control group, indicating that PB biopsy did not affect embryo quality. Following age-adjusted multilevel mixed-effect ordinal logistic regression models performed for each embryo evaluation day, aneuploidy was associated with a decrease in embryo quality on Day 3 (adjusted odds ratio (aOR) 0.62, 95% CI 0.43-0.90), Day 4 (aOR 0.15, 95% CI 0.06-0.39), and Day 5 (aOR 0.28, 95% CI 0.14-0.58). LIMITATIONS, REASON FOR CAUTION: RS cannot be distinguished from normal segregation or MII ND using aCGH. The observed segregations were based on the detected copy number of PB1 and PB2 only and were not confirmed by the analysis of embryos. The embryo morphology assessment was static and single observer. WIDER IMPLICATIONS OF THE FINDINGS: Our finding of frequent unexplained chromosome copy numbers in PBs indicates that our knowledge of the mechanisms causing aneuploidy in oocytes is incomplete. It challenges the dogma that aneuploidy in oocytes is exclusively caused by mis-segregation of chromosomes during MI and MII. STUDY FUNDING/COMPETING INTEREST(S): Data were mined from a study funded by ESHRE. Illumina provided microarrays and other consumables necessary for aCGH testing of PBs. None of the authors have competing interests. TRIAL REGISTRATION NUMBER: Data were mined from the ESTEEM study (ClinicalTrials.gov Identifier NCT01532284).

Permanence of de novo segmental aneuploidy in sequential embryo biopsies.

STUDY QUESTION: Is de novo segmental aneuploidy (SA) a biological event or an artifact that is erroneously interpreted as partial chromosome imbalance? SUMMARY ANSWER: The detection of de novo SA in sequential biopsies of preimplantation embryos supports the biological nature of SA. WHAT IS KNOWN ALREADY: Although some SAs are detected in oocytes and in blastocysts, the highest incidence is observed in cleavage-stage embryos. Based on these findings, we can postulate that the majority of cells affected by SAs are eliminated by apoptosis or that affected embryos mainly undergo developmental arrest. STUDY DESIGN, SIZE, DURATION: This retrospective study includes 342 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between January 2014 and December 2018. Chromosome analysis was performed on 331 oocytes, 886 cleavage-stage embryos and 570 blastocysts (n = 1787). From 268 expanded blastocysts, the blastocoelic fluid (BF) was also analyzed (resulting in 2025 samples in total). In cases of SAs involving loss or gain in excess of 15 Mb, embryos were not considered for transfer and sequential biopsies were performed at following stages. This resulted in 66 sets where the initial diagnosis of SAs (4 made in polar bodies, 25 in blastomeres and 37 in trophectoderm (TE) cells) was followed up. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 2082 samples (2025 + 27 whole embryos) were processed by whole genome amplification followed by array comparative genomic hybridization. MAIN RESULTS AND THE ROLE OF CHANCE: The incidence of SAs was 6.3% in oocytes, increased to 16.6% in cleavage-stage embryos (P < 0.001) and decreased to 11.2% in blastocysts (P < 0.025 versus oocytes; P < 0.01 versus cleavage-stage embryos). The highest incidence of SAs was found in BFs (26.1%, P < 0.001). The analysis of 66 sets of sequential biopsies revealed that the initial finding was confirmed in all following samples from 39 sets (59.1% full concordance). In 12 additional sets, SAs were detected in some samples while in others the interested chromosome had full aneuploidy (18.2%). In three more sets, there was a partial concordance with the initial diagnosis in some samples, but in all TE samples the interested chromosome was clearly euploid (4.5%). In the remaining 12 sets, the initial SA was not confirmed at any stage and the corresponding chromosomes were euploid (18.2% no concordance). The pattern of concordance was not affected by the number of SAs in the original biopsy (single, double or complex) or by the absence or presence of concomitant aneuploidies for full chromosomes. LIMITATIONS, REASONS FOR CAUTION: Chromosome analyses were performed on biopsies that might not be representative of the true constitution of the embryo itself due to the occurrence of mosaicism. WIDER IMPLICATIONS OF THE FINDINGS: The permanence of SAs throughout the following stages of embryo development in more than half of the analyzed sets suggests for this dataset a very early origin of this type of chromosome imbalance, either at meiosis or at the first mitotic divisions. Since SAs remained in full concordance with the initial diagnosis until the blastocyst stage, a corrective mechanism seems not to be in place. In the remaining cases, it is likely that, as for full chromosome aneuploidy, mosaicism derived from mitotic errors could have occurred. In following cell divisions, euploid cell lines could prevail preserving the embryo chances of implantation. Due to the scarcity of data available, the transfer of embryos with SAs should be strictly followed up to establish possible clinical consequences related to this condition. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained. There are no conflicts of interest.

Improving adherence to and persistence with oral therapy of osteoporosis.

UNLABELLED: Osteoporosis treatment has low adherence and persistence. This study evaluated if greater patient involvement could improve them. At 12 months, only 114 out of 344 participants were "fully adherent and persistent" (all drug doses taken throughout the study). Only frequency of drug administration had a significant influence on adherence. INTRODUCTION: Osteoporosis affects millions of individuals worldwide. There are now several effective drugs, but adherence to and persistence with treatment are low. This 12-month multicenter, prospective, randomized study evaluated the efficacy of two different methods aimed at improving adherence and persistence through greater patient involvement, compared with standard clinical practice. METHODS: Three hundred thirty-four post-menopausal women, receiving an oral prescription for osteoporosis for the first time, were recruited and randomized into three groups: group 1 (controls, managed according to standard clinical practice) and groups 2 and 3 (managed with greater patient and caregiver involvement and special reinforcements: group 2, instructed to use several different "reminders"; group 3, same "reminders" as group 2, plus regular phone calls from and meetings at the referring Center). All enrolled women had two visits (baseline and 12 months). RESULTS: Of 334 enrolled women, 247 (74%) started the prescribed therapy. Of those who started, 219 (88.7%) persisted in therapy for at least 10 months. At final evaluation, only 114 women were considered as "fully adherent and persistent" (all doses taken throughout the 12 months). There were no significant differences regarding "full adherence" among the three randomized groups. The frequency of drug administration had a significant influence: weekly administration had a >5-fold higher adherence and monthly administration an 8-fold higher adherence (p < 0.0001) than daily administration. CONCLUSIONS: The special effort of devising and providing additional reminders did not prove effective. Additional interventions during the follow-up, including costly interventions such as phone calls and educational meetings, did not provide significant advantages.

Bone integration of new stemless hip implants (proxima vs. nanos). A DXA study: preliminary results.

The development of short femoral prostheses has the advantage to preserve bone and soft tissues, restore hip geometry, permit mini-invasive techniques and allow quickly return to an active life, but very few studies described bone reaction to these new designed prostheses. The aim of the present study was to evaluate the osseointegration of two different partial neck retained stemless hip prosthesis at one year after surgery, measured by the changes of periprosthetic bone mineral density (BMD) in 5 regions of interest (ROIs) using a dual-energy X ray absorptiometry (DXA) device. The signs of stress-shielding were evaluated by standard radiographs. Thirty-two uncemented primary total hip arthroplasty (THA) patients allocated into 2 groups were evaluated. In the first group (n=19) a Proxima (De-Puy-J&J) hip stem was implanted. In the second group (n=12) a Nanos (Smith & Nephew) hip stem was used. We found that both the implants preserve metaphyseal bone stock and increase periprosthetic BMD. In Nanos prostheses a significant higher BMD values were observed in region of interest (ROI) 3 and 4 (p<0.05). No differences were found in ROIs 1, 2, and 5. Proxima stem seem to produce a physiological strain distribution in the femur. No signs of stress-shielding were present in both the implants. In conclusion, this preliminary DXA analysis showed a physiological integration of both the stems that reproduces the biomechanical stress of proximal femur. New designed short stem implants showed optimal osseointegration after one year, and therefore appears an excellent alternative to traditional long stem hip prostheses.

Quantitative ultrasound of the phalanges and DXA of the lumbar spine and proximal femur in evaluating the risk of osteoporotic vertebral fracture in postmenopausal women.

PURPOSE: This study was undertaken to compare the quantitative ultrasound (QUS) parameters of amplitude-dependent speed of sound (AD-SoS) and ultrasound bone profile index (UBPI) of the phalanges with bone mineral density (BMD) of the lumbar spine and proximal hip using dual-energy X-ray absorptiometry (DXA) in discriminating women with vertebral fracture. MATERIALS AND METHODS: A total of 692 postmenopausal Caucasian women were included in the study. The presence of vertebral fracture was evaluated by radiography. AD-SoS and UBPI were measured at the phalangeal metaphysis using a DBM Sonic device. Multiple logistic regression analysis was performed to estimate the odds ratio (OR) for vertebral fractures. The ORs were also adjusted for the significant anthropometric variables of age, weight and height. Furthermore, for QUS parameters, the ORs were also adjusted for lumbar spine and total hip BMD. RESULTS: All measurements obtained with DXA and QUS significantly discriminated between women with and without fractures (p<0.0001). However, the OR was higher for lumbar spine BMD (OR 4.01), AD-SoS (OR 3.81), total hip (OR 3.7) and femoral neck BMD (OR 3.62). CONCLUSIONS: The QUS parameter AD-SoS showed diagnostic sensitivity equal to that of lumbar DXA in discriminating between women with and without osteoporotic vertebral fractures.

Disruption of transforming growth factor-beta signaling through beta-spectrin ELF leads to hepatocellular cancer through cyclin D1 activation.

Transforming growth factor-beta (TGF-beta) signaling members, TGF-beta receptor type II (TBRII), Smad2, Smad4 and Smad adaptor, embryonic liver fodrin (ELF), are prominent tumor suppressors in gastrointestinal cancers. Here, we show that 40% of elf(+/-) mice spontaneously develop hepatocellular cancer (HCC) with markedly increased cyclin D1, cyclin-dependent kinase 4 (Cdk4), c-Myc and MDM2 expression. Reduced ELF but not TBRII, or Smad4 was observed in 8 of 9 human HCCs (P<0.017). ELF and TBRII are also markedly decreased in human HCC cell lines SNU-398 and SNU-475. Restoration of ELF and TBRII in SNU-398 cells markedly decreases cyclin D1 as well as hyperphosphorylated-retinoblastoma (hyperphosphorylated-pRb). Thus, we show that TGF-beta signaling and Smad adaptor ELF suppress human hepatocarcinogenesis, potentially through cyclin D1 deregulation. Loss of ELF could serve as a primary event in progression toward a fully transformed phenotype and could hold promise for new therapeutic approaches in human HCCs.

NF-kappaB controls cell growth and differentiation through transcriptional regulation of cyclin D1.

Accumulating evidence implicates the transcription factor NF-kappaB as a positive mediator of cell growth, but the molecular mechanism(s) involved in this process remains largely unknown. Here we use both a skeletal muscle differentiation model and normal diploid fibroblasts to gain insight into how NF-kappaB regulates cell growth and differentiation. Results obtained with the C2C12 myoblast cell line demonstrate that NF-kappaB functions as an inhibitor of myogenic differentiation. Myoblasts generated to lack NF-kappaB activity displayed defects in cellular proliferation and cell cycle exit upon differentiation. An analysis of cell cycle markers revealed that NF-kappaB activates cyclin D1 expression, and the results showed that this regulatory pathway is one mechanism by which NF-kappaB inhibits myogenesis. NF-kappaB regulation of cyclin D1 occurs at the transcriptional level and is mediated by direct binding of NF-kappaB to multiple sites in the cyclin D1 promoter. Using diploid fibroblasts, we demonstrate that NF-kappaB is required to induce cyclin D1 expression and pRb hyperphosphorylation and promote G(1)-to-S progression. Consistent with results obtained with the C2C12 differentiation model, we show that NF-kappaB also promotes cell growth in embryonic fibroblasts, correlating with its regulation of cyclin D1. These data therefore identify cyclin D1 as an important transcriptional target of NF-kappaB and reveal a mechanism to explain how NF-kappaB is involved in the early phases of the cell cycle to regulate cell growth and differentiation.

Inhibition of cyclin D1 kinase activity is associated with E2F-mediated inhibition of cyclin D1 promoter activity through E2F and Sp1.

Coordinated interactions between cyclin-dependent kinases (Cdks), their target "pocket proteins" (the retinoblastoma protein [pRB], p107, and p130), the pocket protein binding E2F-DP complexes, and the Cdk inhibitors regulate orderly cell cycle progression. The cyclin D1 gene encodes a regulatory subunit of the Cdk holoenzymes, which phosphorylate the tumor suppressor pRB, leading to the release of free E2F-1. Overexpression of E2F-1 can induce apoptosis and may either promote or inhibit cellular proliferation, depending upon the cell type. In these studies overexpression of E2F-1 inhibited cyclin D1-dependent kinase activity, cyclin D1 protein levels, and promoter activity. The DNA binding domain, the pRB pocket binding region, and the amino-terminal Sp1 binding domain of E2F-1 were required for full repression of cyclin D1. Overexpression of pRB activated the cyclin D1 promoter, and a dominant interfering pRB mutant was defective in cyclin D1 promoter activation. Two regions of the cyclin D1 promoter were required for full E2F-1-dependent repression. The region proximal to the transcription initiation site at -127 bound Sp1, Sp3, and Sp4, and the distal region at -143 bound E2F-4-DP-1-p107. In contrast with E2F-1, E2F-4 induced cyclin D1 promoter activity. Differential regulation of the cyclin D1 promoter by E2F-1 and E2F-4 suggests that E2Fs may serve distinguishable functions during cell cycle progression. Inhibition of cyclin D1 abundance by E2F-1 may contribute to an autoregulatory feedback loop to reduce pRB phosphorylation and E2F-1 levels in the cell.

Inhibition of cellular proliferation through IkappaB kinase-independent and peroxisome proliferator-activated receptor gamma-dependent repression of cyclin D1.

The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-regulated nuclear receptor superfamily member. Liganded PPARgamma exerts diverse biological effects, promoting adipocyte differentiation, inhibiting tumor cellular proliferation, and regulating monocyte/macrophage and anti-inflammatory activities in vitro. In vivo studies with PPARgamma ligands showed enhancement of tumor growth, raising the possibility that reduced immune function and tumor surveillance may outweigh the direct inhibitory effects of PPARgamma ligands on cellular proliferation. Recent findings that PPARgamma ligands convey PPARgamma-independent activities through IkappaB kinase (IKK) raises important questions about the specific mechanisms through which PPARgamma ligands inhibit cellular proliferation. We investigated the mechanisms regulating the antiproliferative effect of PPARgamma. Herein PPARgamma, liganded by either natural (15d-PGJ(2) and PGD(2)) or synthetic ligands (BRL49653 and troglitazone), selectively inhibited expression of the cyclin D1 gene. The inhibition of S-phase entry and activity of the cyclin D1-dependent serine-threonine kinase (Cdk) by 15d-PGJ(2) was not observed in PPARgamma-deficient cells. Cyclin D1 overexpression reversed the S-phase inhibition by 15d-PGJ(2). Cyclin D1 repression was independent of IKK, as prostaglandins (PGs) which bound PPARgamma but lacked the IKK interactive cyclopentone ring carbonyl group repressed cyclin D1. Cyclin D1 repression by PPARgamma involved competition for limiting abundance of p300, directed through a c-Fos binding site of the cyclin D1 promoter. 15d-PGJ(2) enhanced recruitment of p300 to PPARgamma but reduced binding to c-Fos. The identification of distinct pathways through which eicosanoids regulate anti-inflammatory and antiproliferative effects may improve the utility of COX2 inhibitors.

Cyclin D1 is required for transformation by activated Neu and is induced through an E2F-dependent signaling pathway.

The neu (c-erbB-2) proto-oncogene encodes a tyrosine kinase receptor that is overexpressed in 20 to 30% of human breast tumors. Herein, cyclin D1 protein levels were increased in mammary tumors induced by overexpression of wild-type Neu or activating mutants of Neu in transgenic mice and in MCF7 cells overexpressing transforming Neu. Analyses of 12 Neu mutants in MCF7 cells indicated important roles for specific C-terminal autophosphorylation sites and the extracellular domain in cyclin D1 promoter activation. Induction of cyclin D1 by NeuT involved Ras, Rac, Rho, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38, but not phosphatidylinositol 3-kinase. NeuT induction of the cyclin D1 promoter required the E2F and Sp1 DNA binding sites and was inhibited by dominant negative E2F-1 or DP-1. Neu-induced transformation was inhibited by a cyclin D1 antisense or dominant negative E2F-1 construct in Rat-1 cells. Growth of NeuT-transformed mammary adenocarcinoma cells in nude mice was blocked by the cyclin D1 antisense construct. These results demonstrate that E2F-1 mediates a Neu-signaling cascade to cyclin D1 and identify cyclin D1 as a critical downstream target of neu-induced transformation.

NF-kappaB and cell-cycle regulation: the cyclin connection.

The cyclins are a family of proteins that are centrally involved in cell cycle regulation and which are structurally identified by conserved "cyclin box" regions. They are regulatory subunits of holoenzyme cyclin-dependent kinase (CDK) complexes controlling progression through cell cycle checkpoints by phosphorylating and inactivating target substrates. CDK activity is controlled by cyclin abundance and subcellular location and by the activity of two families of inhibitors, the cyclin-dependent kinase inhibitors (CKI). Many hormones and growth factors influence cell growth through signal transduction pathways that modify the activity of the cyclins. Dysregulated cyclin activity in transformed cells contributes to accelerated cell cycle progression and may arise because of dysregulated activity in pathways that control the abundance of a cyclin or because of loss-of-function mutations in inhibitory proteins.Analysis of transformed cells and cells undergoing mitogen-stimulated growth implicate proteins of the NF-kappaB family in cell cycle regulation, through actions on the CDK/CKI system. The mammalian members of this family are Rel-A (p65), NF-kappaB(1) (p50; p105), NF-kappaB(2) (p52; p100), c-Rel and Rel-B. These proteins are structurally identified by an amino-terminal region of about 300 amino acids, known as the Rel-homology domain. They exist in cytoplasmic complexes with inhibitory proteins of the IkappaB family, and translocate to the nucleus to act as transcription factors when activated. NF-kappaB pathway activation occurs during transformation induced by a number of classical oncogenes, including Bcr/Abl, Ras and Rac, and is necessary for full transforming potential. The avian viral oncogene, v-Rel is an NF-kappaB protein. The best explored link between NF-kappaB activation and cell cycle progression involves cyclin D(1), a cyclin which is expressed relatively early in the cell cycle and which is crucial to commitment to DNA synthesis. This review examines the interactions between NF-kappaB signaling and the CDK/CKI system in cell cycle progression in normal and transformed cells. The growth-promoting actions of NF-kappaB factors are accompanied, in some instances, by inhibition of cellular differentiation and by inhibition of programmed cell death, which involve related response pathways and which contribute to the overall increase in mass of undifferentiated tissue.

TGFbeta and PTHrP control chondrocyte proliferation by activating cyclin D1 expression.

Exact coordination of growth plate chondrocyte proliferation is necessary for normal endochondral bone development and growth. Here we show that PTHrP and TGFbeta control chondrocyte cell cycle progression and proliferation by stimulating signaling pathways that activate transcription from the cyclin D1 promoter. The TGFbeta pathway activates the transcription factor ATF-2, whereas PTHrP uses the related transcription factor CREB, to stimulate cyclin D1 promoter activity via the CRE promoter element. Inhibition of cyclin D1 expression with antisense oligonucleotides causes a delay in progression of chondrocytes through the G1 phase of the cell cycle, reduced E2F activity, and decreased proliferation. Growth plates from cyclin D1-deficient mice display a smaller zone of proliferating chondrocytes, confirming the requirement for cyclin D1 in chondrocyte proliferation in vivo. These data identify the cyclin D1 gene as an essential component of chondrocyte proliferation as well as a fundamental target gene of TGFbeta and PTHrP during skeletal growth.

Laparoscopic resection of type 1 choledochal cysts in pediatric patients.

BACKGROUND: Choledochal cyst resection and hepaticojejunostomy have historically been performed using an open technique. We describe here the largest single experience with this procedure using laparoscopic techniques in eight consecutive pediatric patients. METHODS: There were six girls and two boys, of ages ranging from 3 months to 13 years. All had type I choledochal cysts. Three were asymptomatic, having been noted on prenatal ultrasonography. Five ports were utilized: one 5-mm telescope port at the umbilicus, two 3-mm operating ports on both sides of the umbilicus, one 5-mm left subcostal port for liver retraction, and one LLQ 5-mm assistant port. RESULTS: The median operating time was 155 min (range 110-250 min), with one conversion to an open procedure due to a high transection of the cyst leading to partial retraction of the left hepatic duct into the liver substance. Mean hospital stay was 3 days. At a mean follow-up of 18.8 months, all patients were anicteric and asymptomatic. CONCLUSIONS: Laparoscopic resection of choledochal cysts can be performed safely in pediatric patients with minimal morbidity and good long-term results.

Down-regulation of cyclin D1 by transcriptional repression in MCF-7 human breast carcinoma cells induced by flavopiridol.

Flavopiridol is a novel flavonoid that induces cell cycle arrest at different stages of the cell cycle because of the inhibition of cyclin-dependent kinases (cdks). In previous studies from our laboratory, (B. A. Carlson et al., Cancer Res., 56: 2973-2978, 1996), we observed that exposure of the MCF-7 breast carcinoma cell line to flavopiridol resulted in G1-S arrest, which was associated with the loss of cdk4 and cdk2 activity by 24 h of exposure. Along with this inhibition, flavopiridol decreased total cyclin-D protein levels in this cell line. In this work, we demonstrate that using isoform-specific antibodies, flavopiridol induces an early (by 6 h) decrease in cyclin D1 protein levels. This decline is followed by a decline in cyclin D3 with no effect on cyclin D2 or cyclin E levels by 10 h. Furthermore, at early time points (up to 8 h), the activity of cdk4 and the expression of endogenous phosphorylated retinoblastoma species from intact cells exposed to flavopiridol are unchanged. Thus, the decline in cdk4 activity and the induction of retinoblastoma hypophosphorylation follows cyclin D1 decline. Turnover studies demonstrate that the half-life of cyclin D1 (approximately 30 min) is not shortened in flavopiridol-exposed cells, and that the turnover of cdk4-bound cyclin D1 is unaltered. However, steady-state levels of cyclin D1 mRNA display a significant decrease by 4 h of flavopiridol treatment, with total disappearance by 8 h. This mRNA decline is not abrogated by the presence of cycloheximide. Furthermore, we have found that flavopiridol specifically represses the activity of the full-length cyclin D1 promoter linked to a luciferase reporter gene. In summary, we have found that the flavopiridol-induced decline in cyclin D1 is an early event, specific and, at least in part, due to the transcriptional repression of the cyclin D1 promoter. These results extend our understanding of flavopiridol's action to include regulation of cyclin D1 transcription.

Pharmacological and toxicological aspects of 4-demethoxy-3'-deamino-3'-aziridinyl-4'-methylsulphonyl-daunorubicin (PNU-159548): a novel antineoplastic agent.

4-demethoxy-3'-deamino-3'-aziridinyl-4'-methylsulphonyl-daunorubicin (PNU-159548) belongs to a novel class of antitumor compounds (termed alkycyclines) and is currently undergoing Phase II clinical trial. In the present study, we investigated the in vitro and in vivo antitumor activity, the pharmacokinetics, and the toxicological profile of this compound. PNU-159548 showed good cytotoxic activity in murine and human cancer cells growing in vitro, with an average concentration for 50% growth inhibition of 15.8 ng/ml. The drug showed strong antitumor efficacy in vivo after i.v. and p.o. administration against rapidly proliferating murine leukemias and slowly growing transplantable human xenografts. At non-toxic doses, PNU-159548 produced complete regression and cures in ovarian, breast, and human small cell lung carcinomas. Fourteen of 16 models studied, including colon, pancreatic, gastric, and renal carcinomas, astrocytoma and melanoma, were found to be sensitive to PNU-159548. In addition, PNU-159548 was effective against intracranially implanted tumors. Toxicological studies revealed myelosuppression as the main toxicity in both mice and dogs. The maximum tolerated doses, after a single administration, were 2.5 mg/kg of body weight in mice, 1.6 mg/kg in rats, and 0.3 mg/kg in dogs. In the cyclic studies, the maximum tolerated doses were 0.18 mg/kg/day (cumulative dose/cycle: 0.54 mg/kg) in rats and 0.05 mg/kg/day (cumulative dose/cycle: 0.15 mg/kg) in dogs. PNU-159548 showed minimal cardiotoxicity, when compared with doxorubicin in the chronic rat model at a dose level inducing similar myelotoxicity. Animal pharmacokinetics, carried out in mice, rats, and dogs, was characterized by high volumes of distribution, plasma clearance of the same order of the hepatic blood flow, and short terminal half-life. These findings support the conclusion that PNU-159548 is an excellent candidate for clinical trials in the treatment of cancer.

Novel cyclic adenosine 3',5'-monophosphate response element in the human chorionic gonadotropin beta-subunit gene.

CG is encoded by separate alpha- and beta-subunit genes. Expression of both genes is stimulated by cAMP, but the kinetics of activation are different, with cAMP stimulation of the alpha gene preceding that of the beta gene. The cAMP response element (CRE) in the alpha gene contains a palindromic DNA sequence, TGACGTCA, that binds the transcription factor CREB, a nuclear phosphoprotein that is activated by protein kinase-A. Previously, detailed characterization of a CRE in the CG beta gene had been difficult due to low levels of expression in transfected cells. In this study the 5'-flanking sequence of the CG beta gene was fused to a sensitive luciferase (LUC) reporter gene, allowing delineation of a CG beta CRE in transient expression assays performed in JEG-3 choriocarcinoma cells. The full-length CG beta promoter, -3700 to 362 basepairs (bp), was stimulated 8- to 14-fold by treatment with 1 mM 8-bromo-cAMP. Analyses of a series of deletion mutants in the CG beta promoter demonstrated that -311 CG beta LUC retained nearly complete cAMP stimulation, but deletion to -187 bp eliminated cAMP responsiveness. Overlapping DNA fragments between -311 and -30 bp were fused to a heterologous promoter (-99 alpha LUC) to further define the locations of basal elements and CREs. Basal expression required a combination of at least two distinct elements between -311 and -30 bp, whereas cAMP responsiveness was conferred by sequences between -311 and -202 bp. Shorter DNA sequences within this region were insufficient for cAMP stimulation, suggesting that more than one element may be required. DNase-I footprinting and gel mobility shift studies demonstrated at least three distinct protein-binding sites within the CG beta CRE sequence. Recombinant CREB (expressed in E. coli) did not bind to these sites, and they share no sequence homology with the alpha gene CRE, indicating that a cAMP-responsive transcription factor other than CREB interacts with the CG beta promoter.

Stimulation of the P-450 side chain cleavage enzyme (CYP11A1) promoter through ras- and Ets-2-signaling pathways.

Expression of the ovine P-450 side-chain cleavage enzyme gene (CYP11A1) is stimulated by epidermal growth factor (EGF) through a pathway that involves c-Jun in JEG-3 placental cells. Growth factor signaling involves ras-dependent and ras-independent signaling pathways, which in turn regulate gene transcription through related but distinct mitogen-activated protein kinase pathways (MAPKs) including the extracellular signal-regulated kinases (ERKs) and the stress-activated protein kinases (SAPKs). We investigated the intracellular signaling pathways governing EGF induction of the CYP11A1 promoter. EGF stimulation of the CYP11A1 promoter (4-fold) was reduced 60% by a dominant negative mutant of ras (N17), and 30-40% by antisense ras. EGF induced both ERK and SAPK activity in JEG-3 cells. EGF-induced CYP11A1 promoter activity was reduced 60% by the MEK1 inhibitor PD098059 and 50% by a dominant negative mutant of the ERK-specific regulator MEK1. In contrast, dominant negative mutants of the SAPK-specific activator, SEK1, induced a further increase in EGF-induced CYP11A1 promoter activity. Constitutively active mutants of ras (V12 or L61) increased CYP11A1 promoter activity 6- to 8-fold. Deletion of the EGF response element (EGF-RE) between -92 and -77 bp reduced ras induction by 60%; however, a residual 3-fold induction remained through the proximal -77 bp. Mutation of the EGF-RE AP-1-like sequence in the context of the native promoter reduced CYP11A1 promoter activation by ras 60%. The EGF-RE sequence was sufficient for 6-fold activation by ras in the context of an heterologous thymidine kinase promoter. Candidate transcription factor targets (c-Jun, c-Ets-2) for the ras-signaling cascade were examined for their effects on CYP11A1 promoter activity. Overexpression of c-Jun induced the CYP11A1 promoter through the EGF-RE; however, c-Ets-2 activation of the CYP11A1 promoter (12-fold) required the proximal ras-responsive promoter sequences that are distinct from the EGF/MEK/c-Jun-responsive element. Induction of the CYP11A1 promoter by EGF involves a ras/MEK1/AP-1-dependent pathway that is distinct from induction by ras/c-Ets-2.

Activator protein-2 mediates transcriptional activation of the CYP11A1 gene by interaction with Sp1 rather than binding to DNA.

The ovine P45 side chain cleavage (CYP11A1) enzyme gene, which catalyzes the initial enzymatic step in steroid hormone biosynthesis is transcriptionally regulated in cultured steroidogenic human trophoblastic JEG-3 cells. The ovine CYP11A1 promoter contains two GC-rich footprinted regions referred to as ovine footprints 5 (OF5) and OF3, which are well conserved among the CYP11A1 promoters of different species. These GC-rich sequences resemble activator protein-2 (AP-2)/Sp1 binding sites and were previously implicated in basal and cAMP-regulated activity of the bovine and ovine CYP11A1 promoters. In the current studies, AP-2 induced the ovine CYP11A1 promoter 4.5-fold in JEG-3 cells with full induction requiring the previously defined cAMP-responsive elements. Point mutation of OF3 abolished induction by AP-2, and OF3 was sufficient for induction by AP-2 when linked to a heterologous promoter. AP-2 induction of the CYP11A1 promoter required the basic region (N165-N278) and the carboxy terminus of AP-2 (N413-N437). In the course of investigating the mechanisms by which OF5 and OF3 regulated CYP11A1 transcription, we found that OF5 and OF3 bound Sp1 and Sp3 in JEG-3 cells. AP-2 did not bind OF5 or OF3 directly but rather formed a multiprotein complex with Sp1 in JEG-3 cells. AP-2 associated directly with Sp1 in vitro requiring the AP-2 basic region and the Sp1 carboxy terminus. AP-2 induced Sp1/Sp3 activity independently of AP-2 binding to DNA using a GAL4 paradigm. The Sp1 and Sp3 transactivation domains were linked to the DNA-binding domain of GAL4, and their activity was assessed using a luciferase reporter gene containing only the GAL4 DNA-binding sites linked to the minimal TATA site. AP-2 induced Sp1/ Sp3-GAL4 activity 3- to 4-fold, requiring both the amino and extreme carboxy terminus of AP-2. We conclude that AP-2 can bind to and stimulate Sp1 activity and induces the ovine CYP11A1 promoter through conserved Sp1/Sp3-binding sites in JEG-3 cells. The induction of Sp1 activity by AP-2 may contribute to the induction of other genes that bind Sp1.