A screen for regulators of survival of motor neuron protein levels.

The motor neuron disease spinal muscular atrophy (SMA) results from mutations that lead to low levels of the ubiquitously expressed protein survival of motor neuron (SMN). An ever-increasing collection of data suggests that therapeutics that elevate SMN may be effective in treating SMA. We executed an image-based screen of annotated chemical libraries and discovered several classes of compounds that were able to increase cellular SMN. Among the most important was the RTK-PI3K-AKT-GSK-3 signaling cascade. Chemical inhibitors of glycogen synthase kinase 3 (GSK-3) and short hairpin RNAs (shRNAs) directed against this target elevated SMN levels primarily by stabilizing the protein. It was particularly notable that GSK-3 chemical inhibitors were also effective in motor neurons, not only in elevating SMN levels, but also in blocking the death that was produced when SMN was acutely reduced by an SMN-specific shRNA. Thus, we have established a screen capable of detecting drug-like compounds that correct the main phenotypic change underlying SMA.

miRNA malfunction causes spinal motor neuron disease.

Defective RNA metabolism is an emerging mechanism involved in ALS pathogenesis and possibly in other neurodegenerative disorders. Here, we show that microRNA (miRNA) activity is essential for long-term survival of postmitotic spinal motor neurons (SMNs) in vivo. Thus, mice that do not process miRNA in SMNs exhibit hallmarks of spinal muscular atrophy (SMA), including sclerosis of the spinal cord ventral horns, aberrant end plate architecture, and myofiber atrophy with signs of denervation. Furthermore, a neurofilament heavy subunit previously implicated in motor neuron degeneration is specifically up-regulated in miRNA-deficient SMNs. We demonstrate that the heavy neurofilament subunit is a target of miR-9, a miRNA that is specifically down-regulated in a genetic model of SMA. These data provide evidence for miRNA function in SMN diseases and emphasize the potential role of miR-9-based regulatory mechanisms in adult neurons and neurodegenerative states.

Highly Purified Human Menopausal Gonadotropin (HP-hMG) Versus Recombinant Follicle-Stimulating Hormone (rFSH) for Controlled Ovarian Stimulation in US Predicted High-Responder Patients: A Cost-Comparison Analysis.

OBJECTIVES: Infertility imposes considerable clinical and economic burden, and the high costs of fertility care are a major barrier to payers. This study assessed the cost differences of highly purified human menopausal gonadotropin (HP-hMG) versus recombinant follicle stimulating hormone (rFSH) for controlled ovarian stimulation (COS) protocols in predicted high-responders from the US payer perspective. METHODS: A discrete event simulation model was built to perform a cost-comparison analysis of HP-hMG versus rFSH in a cohort of predicted high-responders undergoing up to three embryo transfer cycles, informed by efficacy data from the MEGASET-HR trial. The model considered an event-based treatment pathway and transition probabilities were derived from MEGASET-HR. A variable time horizon was employed, and deterministic and probabilistic sensitivity analyses conducted. RESULTS: Subjects undergoing COS with HP-hMG and rFSH demonstrated comparable live birth rates following three in vitro fertilization (IVF) cycles, with 161 live births with HP-hMG and 152 live births with rFSH, per 310 high-responders. The total cost saving per live birth in subjects receiving HP-hMG versus rFSH was US$3024. These cost savings were largely driven by the need for fewer embryo transfers to achieve similar efficacy outcomes and a reduced rate of ovarian hyperstimulation syndrome. Following deterministic sensitivity analysis, HP-hMG remained cost saving in all baseline parameter variations. No parameters led to rFSH providing cost savings when compared with HP-hMG. CONCLUSION: Comparable clinical outcomes can be achieved at a lower cost when using HP-hMG versus rFSH based COS protocols in a cohort of predicted high-responders. Such cost savings may reduce the economic burden infertility currently presents to US healthcare providers and those seeking fertility care.

Hedgehog is an early and late mediator of pancreatic cancer tumorigenesis.

Hedgehog signalling--an essential pathway during embryonic pancreatic development, the misregulation of which has been implicated in several forms of cancer--may also be an important mediator in human pancreatic carcinoma. Here we report that sonic hedgehog, a secreted hedgehog ligand, is abnormally expressed in pancreatic adenocarcinoma and its precursor lesions: pancreatic intraepithelial neoplasia (PanIN). Pancreata of Pdx-Shh mice (in which Shh is misexpressed in the pancreatic endoderm) develop abnormal tubular structures, a phenocopy of human PanIN-1 and -2. Moreover, these PanIN-like lesions also contain mutations in K-ras and overexpress HER-2/neu, which are genetic mutations found early in the progression of human pancreatic cancer. Furthermore, hedgehog signalling remains active in cell lines established from primary and metastatic pancreatic adenocarcinomas. Notably, inhibition of hedgehog signalling by cyclopamine induced apoptosis and blocked proliferation in a subset of the pancreatic cancer cell lines both in vitro and in vivo. These data suggest that this pathway may have an early and critical role in the genesis of this cancer, and that maintenance of hedgehog signalling is important for aberrant proliferation and tumorigenesis.

Randomized, assessor-blinded trial comparing highly purified human menotropin and recombinant follicle-stimulating hormone in high responders undergoing intracytoplasmic sperm injection.

OBJECTIVE: To evaluate the efficacy and safety of highly purified human menotropin (HP-hMG) and recombinant follicle-stimulating hormone (rFSH) for controlled ovarian stimulation in a population of patients predicted to be high responders. DESIGN: Randomized, open-label, assessor-blinded, parallel-group, noninferiority trial. SETTING: Fertility centers. PATIENT(S): A total of 620 women with serum antimüllerian hormone (AMH) ≥5 ng/mL. INTERVENTION(S): Controlled ovarian stimulation with HP-hMG or rFSH in a GnRH antagonist assisted reproductive technology (ART) cycle. Fresh transfer of a single blastocyst was performed unless ovarian response was excessive, in which all embryos were cryopreserved. Subjects could undergo subsequent frozen blastocyst transfer within 6 months of randomization. MAIN OUTCOME MEASURE(S): Ongoing pregnancy rate (OPR) after fresh transfer (primary endpoint), as well as cumulative live birth, ovarian hyperstimulation syndrome (OHSS), and pregnancy loss rates. RESULTS: OPR/cycle start after fresh transfer was 35.5% with HP-hMG and 30.7% with rFSH (difference: 4.7%, 95% CI -2.7%, 12.1%); noninferiority was established. Compared to rFSH, HP-hMG was associated with significantly lower OHSS (21.4% vs. 9.7% respectively; difference: -11.7%, 95% CI -17.3%, -6.1%) and cumulative early pregnancy loss rates (25.5% vs. 14.5% respectively; difference: -11.0%, 95% CI -18.8%, -3.14%). Despite 43 more transfers in the rFSH group, cumulative live birth rates were similar with HP-hMG and rFSH at 50.6% and 51.5% respectively (difference: -0.8%, 95% CI -8.7%, 7.1%). CONCLUSION(S): In high responders, HP-hMG provided comparable efficacy to rFSH with fewer adverse events, including pregnancy loss, suggesting its optimized risk/benefit profile in this population. CLINICAL TRIAL REGISTRATION NUMBER: NCT02554279 (clinicaltrials.gov).

Economic evaluation of highly purified human menotropin or recombinant follicle-stimulating hormone for controlled ovarian stimulation in high-responder patients: analysis of the Menopur in Gonadotropin-releasing Hormone Antagonist Single Embryo Transfer-High Responder (MEGASET-HR) trial.

OBJECTIVE: To determine the cost of achieving a live birth after first transfer using highly purified human menotropin (HP-hMG) or recombinant follicle-stimulating hormone (FSH) for controlled ovarian stimulation in predicted high-responder patients in the Menopur in Gonadotropin-releasing hormone Antagonist Single Embryo Transfer-High Responder (MEGASET-HR) trial. DESIGN: Cost minimization analysis of trial results. SETTING: Thirty-one fertility centers. PATIENTS: Six hundred and nineteen women with serum antimüllerian hormone ≥5 ng/mL. INTERVENTIONS: Controlled ovarian stimulation with HP-hMG or recombinant FSH in a gonadotropin-releasing hormone (GnRH) antagonist assisted reproduction cycle where fresh transfer of a single blastocyst was performed unless ovarian response was excessive whereupon all embryos were cryopreserved and patients could undergo subsequent frozen blastocyst transfer within 6 months of randomization. MAIN OUTCOME MEASURES: Mean cost of achieving live birth after first transfer (fresh or frozen). RESULTS: First-transfer efficacy, defined as live birth after first fresh or frozen transfer, was 54.5% for HP-hMG and 48.0% for recombinant FSH (difference 6.5%). Average cost to achieve a live birth after first transfer (fresh or frozen) was lower with HP-hMG compared with recombinant FSH. For fresh transfers, the cost was lower with HP-hMG compared with recombinant FSH. The average cost to achieve a live birth after first frozen transfer was also lower in patients treated with HP-hMG compared with recombinant FSH. CONCLUSIONS: Treatment of predicted high-responders with HP-hMG was associated with lower cost to achieve a live birth after first transfer compared with recombinant FSH. CLINICAL TRIAL REGISTRATION NUMBER: NCT02554279.

Stabilization of beta-catenin induces pancreas tumor formation.

BACKGROUND & AIMS: beta-Catenin signaling within the canonical Wnt pathway is essential for pancreas development. However, the pathway is normally down-regulated in the adult organ. Increased cytoplasmic and nuclear localization of beta-catenin can be detected in nearly all human solid pseudopapillary neoplasms (SPN), a rare tumor with low malignant potential. Conversely, pancreatic ductal adenocarcinoma (PDA) accounts for the majority of pancreatic tumors and is among the leading causes of cancer death. Whereas activating mutations within beta-catenin and other members of the canonical Wnt pathway are rare, recent reports have implicated Wnt signaling in the development and progression of human PDA. Here, we sought to address the role of beta-catenin signaling in pancreas tumorigenesis. METHODS: Using Cre/lox technology, we conditionally activated beta-catenin in a subset of murine pancreatic cells in vivo. RESULTS: Activation of beta-catenin results in the formation of large pancreatic tumors at a high frequency in adult mice. These tumors resemble human SPN based on morphologic and immunohistochemical comparisons. Interestingly, stabilization of beta-catenin blocks the formation of pancreatic intraepithelial neoplasia (PanIN) in the presence of an activating mutation in Kras that is known to predispose individuals to PDA. Instead, mice in which beta-catenin and Kras are concurrently activated develop distinct ductal neoplasms that do not resemble PanIN lesions. CONCLUSIONS: These results demonstrate that activation of beta-catenin is sufficient to induce pancreas tumorigenesis. Moreover, they indicate that the sequence in which oncogenic mutations are acquired has profound consequences on the phenotype of the resulting tumor.

Promoting the use of elective single embryo transfer in clinical practice.

BACKGROUND: The transfer of multiple embryos after in vitro fertilization (IVF) increases the risk of twins and higher-order births. Multiple births are associated with significant health risks and maternal and neonatal complications, as well as physical, emotional, and financial stresses that can strain families and increase the incidence of depression and anxiety disorders in parents. Elective single embryo transfer (eSET) is among the most effective methods to reduce the risk of multiple births with IVF. MAIN BODY: Current societal guidelines recommend eSET for patients <35 years of age with a good prognosis, yet even this approach is not widely applied. Many patients and clinicians have been reluctant to adopt eSET due to studies reporting higher live birth rates with the transfer of two or more embryos rather than eSET. Additional barriers to eSET include risk of treatment dropout after embryo transfer failure, patient preference for twins, a lack of knowledge about the risks and complications associated with multiple births, and the high costs of multiple IVF cycles. This review provides a comprehensive summary of strategies to increase the rate of eSET, including personalized counseling, access to educational information regarding the risks of multiple pregnancies and births, financial incentives, and tools to help predict the chances of IVF success. The use of comprehensive chromosomal screening to improve embryo selection has been shown to improve eSET outcomes and may increase acceptance of eSET. CONCLUSIONS: eSET is an effective method for reducing multiple pregnancies resulting from IVF. Although several factors may impede the adoption of eSET, there are a number of strategies and tools that may encourage the more widespread adoption of eSET in clinical practice.

Development and cancer: lessons learned in the pancreas.

Cancer progression and organ development are similar phenomena. Both involve rapid bursts of proliferation, angiogenesis, tissue remodeling, and cell migration. Therefore, it is not surprising that both processes utilize similar signaling machinery. In fact, many recent studies have suggested that cancer is a disease triggered by the erroneous re-activation of signaling pathways that are typically downregulated after the completion of embryonic development. This link between embryonic development and cancer is particularly exciting because it suggests that we might be able to exploit the knowledge gained in studies of Developmental Biology to obtain novel insights into tumor biology. Our evolving understanding of pancreatic adenocarcinoma is an excellent example of this relationship between development and cancer. Here we discuss recent studies have indicated important roles for two major developmental signaling pathways in pancreatic cancer: Notch and Hedgehog (Hh).

Regulated beta-cell regeneration in the adult mouse pancreas.

Several studies have shown that the adult pancreas possesses a limited potential for beta-cell regeneration upon tissue injury. One of the difficulties in studying beta-cell regeneration has been the lack of a robust, synchronized animal model system that would allow controlled regulation of beta-cell loss and subsequent proliferation in adult pancreas. Here we present a transgenic mouse regeneration model in which the c-Myc transcription factor/mutant estrogen receptor (cMycER(TAM)) fusion protein can be specifically activated in mature beta-cells. We have studied these transgenic mice by immunohistochemical and biochemical methods to assess the ablation and posterior regeneration of beta-cells. Activation of the cMycER(TAM) fusion protein results in synchronous and selective beta-cell apoptosis followed by the onset of acute diabetes. Inactivation of c-Myc leads to gradual regeneration of insulin-expressing cells and reversal of diabetes. Our results demonstrate that the mature pancreas has the ability to fully recover from almost complete ablation of all existing beta-cells. Our results also suggest the regeneration of beta-cells is mediated by replication of beta-cells rather than neogenesis from pancreatic ducts.

Wnt signaling regulates pancreatic beta cell proliferation.

There is widespread interest in defining factors and mechanisms that stimulate proliferation of pancreatic islet cells. Wnt signaling is an important regulator of organ growth and cell fates, and genes encoding Wnt-signaling factors are expressed in the pancreas. However, it is unclear whether Wnt signaling regulates pancreatic islet proliferation and differentiation. Here we provide evidence that Wnt signaling stimulates islet beta cell proliferation. The addition of purified Wnt3a protein to cultured beta cells or islets promoted expression of Pitx2, a direct target of Wnt signaling, and Cyclin D2, an essential regulator of beta cell cycle progression, and led to increased beta cell proliferation in vitro. Conditional pancreatic beta cell expression of activated beta-catenin, a crucial Wnt signal transduction protein, produced similar phenotypes in vivo, leading to beta cell expansion, increased insulin production and serum levels, and enhanced glucose handling. Conditional beta cell expression of Axin, a potent negative regulator of Wnt signaling, led to reduced Pitx2 and Cyclin D2 expression by beta cells, resulting in reduced neonatal beta cell expansion and mass and impaired glucose tolerance. Thus, Wnt signaling is both necessary and sufficient for islet beta cell proliferation, and our study provides previously unrecognized evidence of a mechanism governing endocrine pancreas growth and function.

Common activation of canonical Wnt signaling in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) is an extremely aggressive malignancy, which carries a dismal prognosis. Activating mutations of the Kras gene are common to the vast majority of human PDA. In addition, recent studies have demonstrated that embryonic signaling pathway such as Hedgehog and Notch are inappropriately upregulated in this disease. The role of another embryonic signaling pathway, namely the canonical Wnt cascade, is still controversial. Here, we use gene array analysis as a platform to demonstrate general activation of the canonical arm of the Wnt pathway in human PDA. Furthermore, we provide evidence for Wnt activation in mouse models of pancreatic cancer. Our results also indicate that Wnt signaling might be activated downstream of Hedgehog signaling, which is an early event in PDA evolution. Wnt inhibition blocked proliferation and induced apoptosis of cultured adenocarcinoma cells, thereby providing evidence to support the development of novel therapeutical strategies for Wnt inhibition in pancreatic adenocarcinoma.

Stabilization of beta-catenin impacts pancreas growth.

A recent study has shown that deletion of beta-catenin within the pancreatic epithelium results in a loss of pancreas mass. Here, we show that ectopic stabilization of beta-catenin within mouse pancreatic epithelium can have divergent effects on both organ formation and growth. Robust stabilization of beta-catenin during early organogenesis drives changes in hedgehog and Fgf10 signaling and induces a loss of Pdx1 expression in early pancreatic progenitor cells. Together, these perturbations in early pancreatic specification culminate in a severe reduction of pancreas mass and postnatal lethality. By contrast, inducing the stabilized form of beta-catenin at a later time point in pancreas development causes enhanced proliferation that results in a dramatic increase in pancreas organ size. Taken together, these data suggest a previously unappreciated temporal/spatial role for beta-catenin signaling in the regulation of pancreas organ growth.