Dishevelled (Dvl) proteins are intracellular scaffolds protein that act as important regulators of the Wnt signalling pathway. Dvl interac through their PDZ domains with the receptor Frizzled facilitating the dissemination of the Wnt signal. The latest effect of the Wnt activation is the rescue of ß-catenin by degradation, its movement to the nucleus and the transcription of genes associated with tumorigenesis.
The Dvl family comprises 3 isoforms (Dvl1, 2 and 3). Among them Dvl1 plays an imperative role in the Wnt transcriptional activity and its altered expression has been demonstrated in various cancer types contributing to oncogenesis in the liver, colon, cervix and other tissues.
Thus, blocking the Dvl1 PDZ Frizzled interaction represents a valuable and validated approach for cancer treatment.
The aim of this research project is to carry out a virtual screening campaign to identify new small molecule able to impar the Dvl1 Frizzled interaction by targeting the PDZ domain. The compounds selected by the virtual screening will be evaluated in-vitro to have a proof of concept that studied compounds are PDZ binders. The most promising compounds will be submitted to hit-to-lead optimization cycles which implies the design, synthesis and biological evaluation of the new compounds. The hit-to-lead process will take great advantage by the application of computer driven studies such as docking and molecular dynamics etc. Also, common descriptors of drug likeness (MW, logP and solubility) will be computed to prioritize the synthesis of compounds to have faster and hopefully more successful lead compounds identification. The designed compounds will be synthesized and evaluated in a panel of cancer cells to measure the anti-cancer activity and the selectivity index.
The goal of the present research project is the identification of one or more lead compounds with potent anti-tumor activity and improved pharmacokinetic profile to move to an in-vivo animal model evaluation.
PDZ domains are important interaction modules in many intracellular pathways and abnormal activations of many of those pathways lead to diseases, including several types of cancer. The domains are characterized by the ability to recognize the extreme COOH-terminus of target proteins, such as G protein-coupled receptors and ion channels. Because PDZ protein-protein interaction is a key factor in the function of cellular pathways and signal transmission in those pathways, developing small-molecule inhibitors to compete with PDZ targets is very attractive in dissecting molecular mechanisms and formulating pharmaceutical agents [1]. Moreover, there is a growing interest in developing small-molecule drugs to block signaling within cells. About the Dvl PDZ inhibitors just few classes are reported and none of them is featured by acceptable potency or drug like properties [2, 3]. The development of a modulator for targeting the PDZ protein-protein interaction in complex diseases such as Dvl protein and Frz7 receptor in colorectal and breast cancer will give a promising opportunity to understand and to control the biological processes that lead to the cancer development.
The identification of a selective inhibitor of the Dvl1 able to turn off Wnt signalosome may also help to better understand the stemness transition of cancer cells and offers crucial insights to overcome tumor recurrence, metastasis and chemoresistance in clinical management. Stemness combines the ability of a cell to perpetuate its lineage, to give rise to differentiated cells, and to interact with its environment to maintain a balance between quiescence, proliferation, and regeneration. While adult Stem Cells display these properties when participating in tissue homeostasis, Cancer Stem Cells (CSCs) behave as their malignant equivalents. CSCs display stemness in various circumstances, including the sustaining of cancer progression, and the interaction with their environment in search for key survival factors. Recent evidence suggests that activation of Wnt signaling in CSCs contributes to cancer progression in malignant tumors [4]. Indeed, mechanistically in this aberrant transition Dvl proteins play a crucial role. In the hormone-refractory prostate cancer it is observed an overexpression and activity of Dvl3 [4]; in hepatocellular carcinoma is Dvl1 the crucial effector of stem transition [5] while in breast and colorectal cancers, Wnt signaling is not uniformly activated, and there is a considerable degree of heterogeneity in the distribution of cells with high Wnt activity [6]. The complexity of the CSCs transition and behavior may be further clarified by a chemical tool able to turn off the Dvl effectors, thus to help in clarify the role of these proteins in cancer maintenance and survival.
It is widely accepted that a complex system like cancer have to be tackle by a multi-drugs approach. Indeed, this methodology reduce drug resistance, metastasis and increase tolerability of the treatment [7]. In this scenario, this project aims to prove the possibility to treat CRC cells by a coadministration of beta-catenin and Dvl1 inhibitors. To our knowledge this kind of combination it has never been tested. Thus, it could pave the way for a new therapeutic approach to Wnt dependent cancers. This idea risen by recently works of this research unit. Indeed, we demonstrated that the coadministration of beta-catenin and NHERF1 inhibitors, both developed in our laboratories, have a synergistic effect in CRC cell lines [8].
Reference:
1] Wang NX, et al. Drug News Perspect. 2008, 21 137-141;
2] 34. Fujii N, et al. Cancer research. 2007, 67 573-579;
3] Shan J, et al. Chem Biol Drug Design 2012, 79 376-383;
4] Pai CV, et al. Oncogene 2019 38 1340-1353;
5] Liao WY, et al. Stem Cell Reports. 2020, 14 462-477;
6] Vermeulen L, et al. Nat. Cell Biol. 2010, 12 468-476;
7] Mokhatary RB, et al. Oncotarget 2017, 8 38022-38043;
8] Coluccia A, et al. ACS J Med Chem Lett 2019, 10 4 499-503.