Citations

Abstract Transforming growth factor-β (TGF-β) promotes a multitude of diverse biological processes, including growth arrest of epithelial cells and proliferation of fibroblasts. Although the TGF-β signaling pathways that promote inhibition of epithelial cell growth are well characterized, less is known about the mechanisms mediating the positive response to this growth factor. Given that TGF-β has been shown to promote fibrotic diseases and desmoplasia, identifying the fibroblast-specific TGF-β signaling pathways is critical. Here, we investigate the role of mammalian target of rapamycin (mTOR), a known effector of phosphatidylinositol 3-kinase (PI3K) and promoter of cell growth, in the fibroblast response to TGF-β. We show that TGF-β activates mTOR complex 1 (mTORC1) in fibroblasts but not epithelial cells via a PI3K-Akt-TSC2–dependent pathway. Rapamycin, the pharmacologic inhibitor of mTOR, prevents TGF-β–mediated anchorage-independent growth without affecting TGF-β transcriptional responses or extracellular matrix protein induction. In addition to mTORC1, we also examined the role of mTORC2 in TGF-β action. mTORC2 promotes TGF-β–induced morphologic transformation and is required for TGF-β–induced Akt S473 phosphorylation but not mTORC1 activation. Interestingly, both mTOR complexes are necessary for TGF-β–mediated growth in soft agar. These results define distinct and overlapping roles for mTORC1 and mTORC2 in the fibroblast response to TGF-β and suggest that inhibitors of mTOR signaling may be useful in treating fibrotic processes, such as desmoplasia. [Cancer Res 2009;69(1):84–93]

BackgroundWe evaluated the amounts of amyloid beta (Aβ)) peptides in the central nervous system (CNS) and in reservoirs outside the CNS and their potential impact on Aβ plasma levels and Alzheimer's disease (AD) pathology.MethodsAmyloid β levels were measured in (1) the plasma of AD and nondemented (ND) controls in a longitudinal study, (2) the plasma of a cohort of AD patients receiving a cholinesterase inhibitor, and (3) the skeletal muscle, liver, aorta, platelets, leptomeningeal arteries, and in gray and white matter of AD and ND control subjects.ResultsPlasma Aβ levels fluctuated over time and among individuals, suggesting continuous contributions from brain and peripheral tissues and associations with reactive circulating proteins. Arteries with atherosclerosis had larger amounts of Aβ40 than disease‐free vessels. Inactivated platelets contained more Aβ peptides than activated ones. Substantially more Aβ was present in liver samples from ND patients. Overall, AD brain and skeletal muscle contained increased levels of Aβ.ConclusionsEfforts to use plasma levels of Aβ peptides as AD biomarkers or disease‐staging scales have failed. Peripheral tissues might contribute to both the circulating amyloid pool and AD pathology within the brain and its vasculature. The wide spread of plasma Aβ values is also due in part to the ability of Aβ to bind to a variety of plasma and membrane proteins. Sources outside the CNS must be accounted for because pharmacologic interventions to reduce cerebral amyloid are assessed by monitoring Aβ plasma levels. Furthermore, the long‐range impact of Aβ immunotherapy on peripheral Aβ sources should also be considered.

Abstract Purpose: p27 localization and expression has prognostic and predictive value in cancer. Little is known regarding expression patterns of p27 in renal cell carcinoma (RCC) or how p27 participates in disease progression or response to therapy. Experimental Design: RCC-derived cell lines, primary tumors, and normal renal epithelial cells were analyzed for p27 expression, phosphorylation (T157 of the NLS), and subcellular localization. RCC-derived cell lines were treated with phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitors and effects on p27 localization were assessed. The potential contribution of cytoplasmic p27 to resistance to apoptosis was also evaluated. Results: p27 was elevated in tumors compared with matched controls, and cytoplasmic mislocalization of p27 was associated with increasing tumor grade. Cytoplasmic localization of p27 correlated with phosphorylation at T157, an AKT phosphorylation site in the p27 NLS. In RCC cell lines, activated PI3K/AKT signaling was accompanied by mislocalization of p27. AKT activation and phosphorylation of p27 was associated with resistance to apoptosis, and small interfering RNA knockdown of p27 or relocalization to the nucleus increased apoptosis in RCC cells. Treatment with the PI3K inhibitors LY294002 or wortmannin resulted in nuclear relocalization of p27, whereas mTOR inhibition by rapamycin did not. Conclusions: In RCC, p27 is phosphorylated at T157 of the NLS, with increasing tumor grade associated with cytoplasmic p27. PI3K inhibition (which reduces AKT activity) reduces T157 phosphorylation and induces nuclear relocalization of p27, whereas mTOR inhibition does not. Clinical testing of these findings may provide a rational approach for use of mTOR and PI3K/AKT pathway inhibitors in patients with RCC.

Abstract Ice hockey is a fast-paced, aggressive sport whose participants are subject to relatively high rates of injury. Although there is a growing emphasis on the epidemiology of ice hockey research and its application towards reducing injuries, the literature has never been organized into an accessible database. Ice hockey is played in North America, Europe, Scandinavia, the U.K., and several other non-English speaking countries, yet injury reports not written in English are often ignored in review articles. The purpose of this project was to synthesize the existing world literature on ice hockey injuries into a framework of epidemiologic criteria, accessible in an organized, retrievable library. An extensive search of the following databases was done: MEDLINE, BIOSIS, EMBASE, NTIS, CURRENT CONTENTS, DISSERTATION ABSTRACTS, SPORT DISCUS, CINAHL, and WEB OF SCIENCE. Key words used were “ice hockey” and “injuries,” and the search range was 1966 to July 2007. Endnote X (Thompson Corp., Stamford, CT) was used for reference compilation. Eight hundred sixty seven documents were catalogued, from 27 countries in 8 languages. Documents were first categorized by type, including injury (226), equipment (45), case reports (94), review articles (294), editorials (39), or as focusing on the physiological, psychological, or medical aspects of ice hockey (169). Documents were then subdivided by study type and whether they were prospective (117) or retrospective (109). Further subdivisions beyond these levels were based on the inclusion of certain critical epidemiological criteria, including exposure time, a clear definition of “injury,” and the level of play, among others. This comprehensive database should make future ice hockey research more efficient, as well as promote sound epidemiology and a more global perspective.

Showcased in this article is an interview with Carlo C. DiClemente, PhD, an internationally renowned health behavior researcher and codeveloper of the Transtheoretical or Stages of Change Model. In this verbatim interview transcript, later edited by the authors and interviewee, Dr. DiClemente, he provides practical information and frank commentary on the steps to follow and pitfalls to avoid in developing, implementing, evaluating, and disseminating efficacious programs for affecting the health and well-being of individuals and populations. A concluding section summarizes key lessons learned from the professional experiences of Dr. DiClemente and discusses implications for advancing health behavior intervention practice and research.

Purpose To analyze the Radiation Therapy Oncology Group (RTOG) database of patients with glioblastoma and appraise whether outcome was influenced by time to initiation of radiation therapy (RT). Patients and Methods From 1974 through 2003, adult patients with histologically confirmed supratentorial glioblastoma were enrolled onto 16 RTOG studies. Of 3,052 enrolled patients, 197 patients (6%) were either initially rendered ineligible or had insufficient chronologic data, leaving a cohort of 2,855 patients for the present analysis. We selected four patient groups based on the interval from surgery to the start of RT: ≤ 2 weeks, 2 to 3 weeks, 3 to 4 weeks, more than 4 weeks to the protocol eligibility limit of 6 weeks. Survival times were estimated by the Kaplan-Meier method. Multivariate analysis incorporated variables of time interval, recursive partitioning analysis (RPA) class, and treatment regimen. Results No decrement in survival could be identified with increasing time to initiation of RT. Among our four temporal groupings, median survival time was unexpectedly and significantly greater in the group with the longest interval (> 4 weeks) than in those with the shortest delay (≤ 2 weeks): respectively, 12.5 months versus 9.2 months (P < .0001). On multivariate analysis, with overall survival as the end point, time interval more than 4 weeks and lower RPA class were both significant predictors of improved outcome. Treatment regimen was not a significant factor. Conclusion There is no evident reduction in survival by delaying initiation of RT within the relatively narrow constraint of 6 weeks. An unanticipated yet significantly superior outcome was identified for patients for whom RT was delayed beyond 4 weeks from surgery.