Suppression of Estrogen Receptor Transcriptional Activity by Connective Tissue Growth Factor

Secreted growth factors have been shown to stimulate the transcriptional activity of estrogen receptors (ER) that are responsible for many biological processes. However, whether these growth factors physically interact with ER remains unclear. Here, we show for the first time that connective tissue growth factor (CTGF) physically and functionally associates with ER. CTGF interacted with ER both in vitro and in vivo. CTGF interacted with ER DNA-binding domain. ER interaction region in CTGF was mapped to the thrombospondin type I repeat, a cell attachment motif. Overexpression of CTGF inhibited ER transcriptional activity as well as the expression of estrogen-responsive genes, including pS2 and cathepsin D. Reduction of endogenous CTGF with CTGF small interfering RNA enhanced ER transcriptional activity. The interaction between CTGF and ER is required for the repression of estrogen-responsive transcription by CTGF. Moreover, CTGF reduced ER protein expression, whereas the CTGF mutant that did not repress ER transcriptional activity also did not alter ER protein levels. The results suggested the transcriptional regulation of estrogen signaling through interaction between CTGF and ER, and thus may provide a novel mechanism by which cross-talk between secreted growth factor and ER signaling pathways occurs

European perspective for effective cancer drug development

Health systems and the clinical research landscape evolve continuously owing to increased risk aversion, scrutiny by funding bodies, and costs of clinical trials. In this context, however, current drug development procedures are far from optimal, as exemplified by the late-stage failure of several drugs. The identification of new drugs urgently requires approaches based on a solid understanding of cancer biology, and that will support the design of robust confirmatory trials. The complexity and the costs of drug development are now beyond the knowledge and operational capacity of single organisations, therefore, a drastic deviation from the traditional path of drug discovery and new forms of multidisciplinary partnerships are needed to succeed in this sector. The European Organisation for Research and Treatment of Cancer (EORTC) proposes the use of collaborative molecular screening platforms (CMSPs) as a new approach to tackle this issue. These CMSPs have the advantage of optimizing the expertise of several partners and combining efforts alongside with cost-sharing models for efficient patient selection. This article describes some of the challenges to advancing drug development and improving medical treatments and how these hurdles can be overcome