No abstract

Primary prostate cancer is generally treatable by androgen deprivation therapy, however, later recurrences of castrate-resistant prostate cancer (CRPC) that are more difficult to treat nearly always occur due to aberrant reactivation of the androgen receptor (AR). In this study, we report that CRPC cells are particularly sensitive to the growth-inhibitory effects of reengineered tricyclic sulfonamides, a class of molecules that activate the protein phosphatase PP2A, which inhibits multiple oncogenic signaling pathways. Treatment of CRPC cells with small-molecule activators of PP2A (SMAP) decreased cellular viability and clonogenicity and induced apoptosis. SMAP treatment also induced an array of significant changes in the phosphoproteome, including most notably dephosphorylation of full-length and truncated isoforms of the AR and downregulation of its regulatory kinases in a dose-dependent and time-dependent manner. In murine xenograft models of human CRPC, the potent compound SMAP-2 exhibited efficacy comparable with enzalutamide in inhibiting tumor formation. Overall, our results provide a preclinical proof of concept for the efficacy of SMAP in AR degradation and CRPC treatment. A novel class of small-molecule activators of the tumor suppressor PP2A, a serine/threonine phosphatase that inhibits many oncogenic signaling pathways, is shown to deregulate the phosphoproteome and to destabilize the androgen receptor in advanced prostate cancer. .

BACKGROUND: Off-label drug use in children is common and potentially harmful. In most previous off-label use research, authors studied hospitalized children, specific drug classes, or non-US settings. We characterized frequencies, trends, and reasons for off-label systemic drug orders for children in ambulatory US settings.METHODS: Using nationally representative surveys of office-based physicians (National Ambulatory Medical Care Surveys, 2006, we studied off-label orders of systemic drugs for children age ,18 based on US Food and Drug Administration-approved labeling for age, weight, and indication. We characterized the top classes and diagnoses with off-label orders and analyzed factors and trends of off-label orders using logistic regression.RESULTS: Physicians ordered $1 off-label systemic drug at 18.5% (95% confidence interval: 17.7%-19.3%) of visits, usually (74.6%) because of unapproved conditions. Off-label ordering was most common proportionally in neonates (83%) and in absolute terms among adolescents (322 orders out of 1000 visits). Off-label ordering was associated with female sex, subspecialists, polypharmacy, and chronic conditions. Rates and reasons for off-label orders varied considerably by age. Relative and absolute rates of off-label orders rose over time. Among common classes, off-label orders for antihistamines and several psychotropics increased over time, whereas off-label orders for several classes of antibiotics were stable or declined.CONCLUSIONS: US office-based physicians have ordered systemic drugs off label for children at increasing rates, most often for unapproved conditions, despite recent efforts to increase evidence and drug approvals for children. These findings can help inform education, research, and policies around effective, safe use of medications in children.WHAT'S KNOWN ON THIS SUBJECT: In past studies, pediatric off-label use was shown to be common and potentially harmful, but researchers have focused predominantly on acute care settings, specific classes of drugs, outpatient prescribing outside the United States, or older data sources. WHAT THIS STUDY ADDS:In 2006-2015, US office-based physicians ordered systemic drugs off label for children at rising rates, particularly for unapproved conditions. Updated data on common off-label drugs, classes, and unapproved conditions treated in children will help inform education, research, and policies.