The Hedgehog (Hh) pathway has emerged as important therapeutic target in cancer, since its crucial role in tissues,development, proliferation and maintenance of cancer stem cells (CSCs) in tumors. The major issue in Hh-antagonist
development is due to drug-resistant Smo mutations and Gli1 hyperactivation.The clinical development of Smo antagonists has failed due to different issues including pharmacokinetics, low selectivity on CSCs or the emergence of drug resistance. Several evidences also suggest that cancer cells can acquire resistance to Smo antagonists by amplification/activation of Gli effectors or activation of external coordinated signals that bypass the Smo-mediated control. Therefore, the development of new compounds that could modulate Hh pathway has emerged as a better approach to cancer therapy. Due to structure-based approach and multidisciplinary efforts, we recently discovered the first small molecule, GlaB, able to impair Hh oncogenic activity by inhibiting Gli1/DNA interaction, providing a proof-of-principle for the therapeutic relevance of such an approach. We will investigate the translational potential of GlaB and we will test whether this strategy provide valuable insights for identifying, developing and optimizing new Smo and/or Gli-antagonists and promise a more effective treatment in Hh-dependent tumors and CSCs. The main goal of this proposal is the discovery of novel small molecules targeting Hh signaling at both upstream and downstream level to overcome anti-Smo resistance and affect Gli1/DNA interaction and its transcriptional function.A multidisciplinary research team will be established by mixing organometallic chemistry, plant natural compounds extracted by different matrices,plant natural compounds extracted by different matrices and computational studies, engineer and molecular biology expertise.Most promising compounds will be tested in vitro and in vivo for their efficacy to counteract the Hh-dependent tumors and CSCs growth.
Hedgehog (Hh) signaling plays a pivotal role in tissue development and stemness and its deregulation is found in many tumors. The main aim of this project is the identification of novel biomolecules able of antagonizing both Smoothened/Hh receptor and Gli1-mediated transcription, which constitute the final step in the Hh pathway activation. Particular attention will be focused to investigate the pharmacological effects of the selected compounds in cancer stem cells, an important issues to overcome the drug-resistance. This goal requires the effective cooperation of medicinal, computational and organic chemists accompanied by cell biologists and oncologists with expertise in rational drug design and the medicinal chemistry of synthetic and natural compounds with biomedical investigators dedicated to the understanding the mechanisms governing drug resistance in cancer stem cells.
The project brings together 3 research teams from different fields that will dissect different aspects related to the aberrant activation of Hh pathway in CSC, beyond to the identification of small molecule antagonists of Hh, efficacy in tumors treatment. The activity of Hh pathway is regulated at multiple levels by diverse mechanisms including negative and/or positive regulators influencing stability, subcellular localization and activity of Gli transcription factors.
Alterations in these processes may occur by both Smo-dependent, upstream pathway activation and/or Smo-independent, downstream pathway activation, mechanisms leading to increased function of the Gli proteins, in particular of Gli1, the final and most powerful effector of the Hh signaling, and crucial regulator of stemness genes, such as Nanog (Po et al. 2010). ). Hh pathway in mammalian cells is parallel to the morphogenic pathway in Candida albicans. The homologue of HHATL protein that is regulator the Hedgehog signal secretion is in yeast Gup1. In yeast, the deletion of GUP1 is associated with a vast number of diverse phenotypes including the cellular differentiation that accompanies biofilm formation, an important virulence factor (Ferreira, et BMC Microbiology201010:238Faria-Oliveira et al.. BMC Microbiol. 15:271. 2015). Some active molecules on Hedgehog pathway in tumors and cancer stem cells inhibit the growth of various fungi and yeasts. (Meng and Sikorski.. Expert Opinion on Therapeutic Patents.14: 1669-1691. 2004; Batovskaa et al. European Journal of Medicinal Chemistry 42: 87¿92. 2007) and compounds with antifungal activity demonstrated to be active on Hedgehog signaling pathway (Kim,et al. Cancer Cell Volume 17: 388¿399. 2010)
For this reason, important object of this proposal is the discovery of new effective Hh inhibitors able to hit CSCs to identify innovative and more effective anti-cancer therapies.
This ambitious proposal would lead to selection, prioritization and optimization of new classes of compounds, synthetic and natural from plants by a ligand-based molecular modeling or structure-based approaches and their synthesis through innovative and sustainable chemical processes, a priority of modern chemistry.
Research efforts will focus on 2 themes: a) selection, optimization and synthesis by sustainable processes of new Hh inhibitors; b) therapeutic targeting of Hh pathway in tumors and CSCs.
All area of investigation will interact extensively with each other and will profit from the products generated by Rome OU1 research efforts focused on the design and synthesis of new compounds and /or testing natural products from plants, capable of targeting Hh pathway activity at the multiple levels.