TLN-4601 is a structurally novel farnesylated dibenzodiazepinone discovered through DECIPHER, Thallion's proprietary drug discovery platform. The compound was shown to have a broad cytotoxic activity (low micromol/l) when tested in the NCI 60 tumor cell line panel and has shown in-vivo antitumor activity in several xenograft models. Related to its farnesylated moiety, the effect of TLN-4601 on Ras mitogen-activated protein kinase signaling was assessed. Downstream Ras signaling events, Raf-1, MEK, and ERK1/2 phosphorylation in MCF7 cells were evaluated by western blot analysis. TLN-4601 prevented epidermal growth factor-induced phosphorylation of Raf-1, MEK, and ERK1/2. This effect was time-dependent and dose-dependent with complete inhibition of protein phosphorylation within 4-6 h at 10 micromol/l. The inhibition of Ras signaling was not mediated by the inhibition of protein prenylation, documented by the lack of effect TLN-4601 on the prenylation of HDJ2 (specific substrate of farnesyltransferase), RAP1A (specific substrate of geranylgeranyl transferase-1), or Ras. As TLN-4601 did not inhibit EGFR, Raf-1, MEK or ERK1/2 kinase activities, the inhibitory effect of TLN-4601 on Ras signaling is not mediated by direct kinase inhibition. Using an Elk-1 trans-activation reporter assay, we found that TLN-4601 inhibits the MEK/ERK pathway at the level of Raf-1. Interestingly, TLN-4601 induces Raf-1 proteasomal-dependent degradation. These data indicate that TLN-4601 may inhibit the Ras-mitogen-activated protein kinase-signaling pathway by depleting the Raf-1 protein.
Cansearch Research Platform for Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Background: We previously demonstrated that APR-246 (eprenetapopt) could be an efficient treatment option against neuroblastoma (NB), the most common pediatric extracranial solid tumor. APR-246's mechanism of action is not completely understood and can differ between cell types. Here we investigate the involvement of well-known oncogenic pathways in NB's response to APR-246.
The mechanistic target of rapamycin complex 1 (mTORC1) functions as a master regulator of cell growth and proliferation. We previously demonstrated that intracellular calcium ion (Ca) concentration modulates the mTORC1 pathway via binding of the Ca sensor protein calmodulin (CaM) to tuberous sclerosis complex 2 (TSC2), a critical negative regulator of mTORC1. However, the precise molecular mechanism by which Ca/CaM modulates mTORC1 activity remains unclear.
Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, 600077, India.
Introduction: This scoping review aimed to review the various challenges facing dental education. Dental education faces multiple institutional, student and faculty-based challenges. Institutional challenges include updating infrastructure resources, recruiting qualified faculty, and implementing administrative policies that enhance dental education.
Department of Hematology, The First Affiliated Hospital of USTC, Key Laboratory of Immune Response and Immunotherapy, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Institute of Blood and Cell Therapy and Anhui Provincial Key Laboratory of Blood Research and Applications, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
The engraftment of haematopoietic stem and progenitor cells (HSPCs), particularly in cord-blood transplants, remains challenging. Here we report the role of the corticotropin-releasing hormone (CRH) in enhancing the homing and engraftment of human-cord-blood HSPCs in bone marrow through mechanical remodelling. By using microfluidics, intravital two-photon imaging and long-term-engraftment assays, we show that treatment with CRH substantially enhances HSPC adhesion, motility and mechanical remodelling, ultimately leading to improved bone-marrow homing and engraftment in immunodeficient mice.
