Inhibiting endothelial cell function in normal and tumor angiogenesis using BMP type I receptor macrocyclic kinase inhibitors

Simple Summary Anti-angiogenesis agents have shown anti-cancer activity by preventing blood vessel ingrowth, thereby limiting tumour growth and metastasis. Although these molecules lead to prolonged overall survival of cancer patients, therapy resistance is easily acquired. Therefore, novel inhibitors against other signaling pathways mediating angiogenesis are needed to achieve more efficient and sustainable targeting of the angiogenesis process. Here, we synthesized and identified two compounds belonging to a new class of small molecules termed macrocyclics that selectively inhibit bone morphogenetic protein receptor kinase activity. One compound also inhibits vascular endothelial growth factor-induced signalling. Treatment studies using in vitro cultured cells and zebrafish embryos revealed that both compounds impaired endothelial cell function and decreased normal and tumour-induced angiogenesis. Both compounds might provide a steppingstone for the development of novel-angiogenesis therapeutic agents. Angiogenesis, i.e., the formation of new blood vessels from pre-existing endothelial cell (EC)-lined vessels, is critical for tissue development and also contributes to neovascularization-related diseases, such as cancer. Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMPs) are among many secreted cytokines that regulate EC function. While several pharmacological anti-angiogenic agents have reached the clinic, further improvement is needed to increase clinical efficacy and to overcome acquired therapy resistance. More insights into the functional consequences of targeting specific pathways that modulate blood vessel formation may lead to new therapeutic approaches. Here, we synthesized and identified two macrocyclic small molecular compounds termed OD16 and OD29 that inhibit BMP type I receptor (BMPRI)-induced SMAD1/5 phosphorylation and downstream gene expression in ECs. Of note, OD16 and OD29 demonstrated higher specificity against BMPRI activin receptor-like kinase 1/2 (ALK1/2) than the commonly used small molecule BMPRI kinase inhibitor LDN-193189. OD29, but not OD16, also potently inhibited VEGF-induced extracellular regulated kinase MAP kinase phosphorylation in ECs. In vitro, OD16 and OD29 exerted strong inhibition of BMP9 and VEGF-induced ECs migration, invasion and cord formation. Using Tg (fli:EGFP) zebrafish embryos, we found that OD16 and OD29 potently antagonized dorsal longitudinal anastomotic vessel (DLAV), intra segmental vessel (ISV), and subintestinal vessel (SIV) formation during embryonic development. Moreover, the MDA-MB-231 breast cancer cell-induced tumor angiogenesis in zebrafish embryos was significantly decreased by OD16 and OD29. Both macrocyclic compounds might provide a steppingstone for the development of novel anti-angiogenesis therapeutic agents.Cancer Signaling networks and Molecular Therapeutic

The TGF-β/Smad Repressor TG-Interacting Factor 1 (TGIF1) Plays a Role in Radiation-Induced Intestinal Injury Independently of a Smad Signaling Pathway

Despite advances in radiation delivery protocols, exposure of normal tissues during the course of radiation therapy remains a limiting factor of cancer treatment. If the canonical TGF-β/Smad pathway has been extensively studied and implicated in the development of radiation damage in various organs, the precise modalities of its activation following radiation exposure remain elusive. In the present study, we hypothesized that TGF-β1 signaling and target genes expression may depend on radiation-induced modifications in Smad transcriptional co-repressors/inhibitors expressions (TGIF1, SnoN, Ski and Smad7). In endothelial cells (HUVECs) and in a model of experimental radiation enteropathy in mice, radiation exposure increases expression of TGF-β/Smad pathway and of its target gene PAI-1, together with the overexpression of Smad co-repressor TGIF1. In mice, TGIF1 deficiency is not associated with changes in the expression of radiation-induced TGF-β pathway-related transcripts following localized small intestinal irradiation. In HUVECs, TGIF1 overexpression or silencing has no influence either on the radiation-induced Smad activation or the Smad3-dependent PAI-1 overexpression. However, TGIF1 genetic deficiency sensitizes mice to radiation-induced intestinal damage after total body or localized small intestinal radiation exposure, demonstrating that TGIF1 plays a role in radiation-induced intestinal injury. In conclusion, the TGF-β/Smad co-repressor TGIF1 plays a role in radiation-induced normal tissue damage by a Smad-independent mechanism

Sensitivity and dose dependency of radiation-induced injury in hematopoietic stem/progenitor cells in mice

We evaluated the sensitivity and dose dependency of radiation-induced injury in hematopoietic stem/progenitor cells. Adult C57BL/6 mice were daily exposed to 0, 2, 10, 50, and 250 mGy γ-ray for 1 month in succession, respectively. The damage of hematopoietic stem/progenitor cells in bone marrow were investigated within 2 hours (acute phase) or at 3 months (chronic phase) after the last exposure. Daily exposure to over 10 mGy γ-ray significantly decreased the number and colony-forming capacity of hematopoietic stem/progenitor cells at acute phase, and did not completely recover at chronic phase with 250 mGy exposure. Interestingly, the daily exposure to 10 or 50 mGy γ-ray decreased the formation of mixed types of colonies at chronic phase, but the total number of colonies was comparable to control. Immunostaining analysis showed that the formation of 53BP1 foci in c-kit + stem/progenitor cells was significantly increased with daily exposure to 50 and 250 mGy at acute phase, and 250 mGy at chronic phase. Many genes involved in toxicity responses were up- or down-regulated with the exposures to all doses. Our data have clearly shown the sensitivity and dose dependency of radiation-induced injury in hematopoietic stem/progenitor cells of mice with daily exposures to 2 ? 250 mGy γ-ray

Human keratinocyte radiosensitivity is linked to redox modulation

Background: Ionising radiation-induced reactive oxygen species (ROS) overproduction induces keratinocyte alterations and constitutes one of the most common effects after therapeutic γ-irradiation. ROS production is controlled by a complex enzymatic system. Objective: The aim of our study is to analyse the role of radiation-induced oxidative stress in keratinocytes death by apoptosis. We hypothesized that keratinocyte capacity to hamper radiation-induced ROS generation may control their radiosensitivity. Methods: For this purpose, an original human skin explant model was developed and two types of human epidermal cells were used: primary keratinocytes NHEK and spontaneous non-tumourigenic cell line HaCaT. Results: cDNA-arrays analysis was performed 24 h after a 20 Gy γ-radiation and revealed down-regulation of genes involved in oxidative stress control and the apoptosis process. This was confirmed by alterations in catalase, GPx and SOD enzymatic activities. This redox modulation was concomitant to the down-regulation of anti-apoptotic genes and up-regulation of some pro-apoptotic genes (caspase 10, ubiquitin C). Interestingly TUNEL labelling revealed an increase in the number of apoptotic cells. We also demonstrated a differential inducibility of the cell antioxidant network in two keratinocyte lines, which results in a differential cellular level of ROS, explaining their different radiosensitivities. Conclusion: Keratinocytes apoptosis is partly dependent on ROS production after exposure to γ-rays. In addition, the differential radiosensitivity of keratinocytes is linked to different oxidative stress responses. © 2005 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved

Stem cell therapy From bench to bedside

International audienceSeveral countries have increased efforts to develop medical countermeasures to protect against radiation toxicity due to acts of bioterrorism as well as cancer treatment. Both acute radiation injuries and delayed effects such as cutaneous effects and impaired wound repair depend, to some extent, on angiogenesis deficiency. Vascular damage influences levels of nutrients, oxygen available to skin tissue and epithelial cell viability. Consequently, the evolution of radiation lesions often becomes uncontrolled and surgery is the final option-amputation leading to a disability. Therefore, the development of strategies designed to promote healing of radiation injuries is a major therapeutic challenge. Adult mesenchymal stem cell therapy has been combined with surgery in some cases and not in others and successfully applied in patients with accidental radiation injuries. Although research in the field of radiation skin injury management has made substantial progress in the past 10 y, several strategies are still needed in order to enhance the beneficial effect of stem cell therapy and to counteract the deleterious effect of an irradiated tissue environment. This review summarises the current and evolving advances concerning basic and translational research based on stem cell therapy for the management of radiological burns. © World Health Organization 2012. All rights reserved

Development of macrocycle kinase inhibitors for ALK2 using Fibrodysplasia ossificans progressiva‐derived endothelial cells

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare congenital form of heterotopic ossification (HO), caused by heterozygous mutations in the Activin A type I receptor (ACVR1), that encodes the bone morphogenetic protein (BMP) type I receptor ALK2. These mutations enable ALK2 to induce downstream signaling in response to Activins, thereby turning them into bone inducing agents. To date there is no cure for FOP. The further development of FOP patient‐derived models may contribute to discover novel biomarkers and therapeutic approaches. Nevertheless, this has traditionally been a challenge, as biopsy sampling often triggers HO. We have characterized peripheral blood‐derived endothelial colony forming cells (ECFCs) from three independent FOP donors as a new model for FOP. FOP ECFCs are prone to undergo Endothelial‐to‐mesenchymal transition and exhibit increased ALK2 downstream signaling and subsequent osteogenic differentiation upon stimulation with Activin A. Moreover, we have identified a new class of small molecule macrocycles with potential activity against ALK2 kinase. Finally, using FOP ECFCs, we have selected OD36 and OD52 as potent inhibitors with excellent kinase selectivity profiles that potently antagonize mutant ALK2 signaling and osteogenic differentiation. We expect that these results will contribute to the development of novel ALK2 clinical candidates for the treatment of FOP. </p

Development of small macrocyclic kinase inhibitors

Cancer Signaling networks and Molecular Therapeutic

Development of small macrocyclic kinase inhibitors

Cancer Signaling networks and Molecular Therapeutic