Enhancing anticancer activity of spiropyrazoline oxindoles by disrupting p53-MDMs PPIs

Cancer is a major public health problem worldwide with 18.1 million new cases of cancer and 9.6 million deaths worldwide in 2018¹.

The protein p53 is involved in many biological processes that are important to maintain the normal function of the cells (e.g. apoptosis, cell arrest, and DNA repair). It is an attractive target in oncology because it can modulate several additional cellular processes that are relevant for the suppression of tumour development, such as opposing oncogenic metabolic reprogramming, activating autophagy, and restraining invasion and metastasis. In all types of human cancers, the p53 tumour suppressor function is inactivated by mutation or gene deletion or by negative regulators such as MDM2 and MDMX. In the last years, the most popular approach among medicinal chemists to activate the wild-type p53 was the inhibition of p53-MDM2 protein-protein interaction (PPI) using small molecules. However, it is currently known that the full reactivation of p53 is only achieved when the interactions of p53 with both negative regulators are inhibited. Due to the lack of dual p53-MDM2/X PPIs inhibitors in clinical trials, it is urgent to develop small molecules that inhibit p53-MDMs PPIs².

Our research team has been working on the development and optimization of spiropyrazoline oxindoles to obtain dual p53-MDM2/X PPIs inhibitors. Hence, we have already developed derivatives with good antiproliferative activities in HCT-116 p53(+/+) human colorectal carcinoma cell line, which induce apoptosis and cell cycle arrest at G0/G1 phase, upregulate p53 steady-state levels, and lead to a decrease of MDM2 levels³. In this communication, we report the structure-based computational optimization of this chemical family for the development of novel p53-MDM2/X interactions inhibitors. Our studies will shed light on the possible binding mode of spirooxindole derivatives to MDM2 and MDMX and will drive the hit-to-lead optimization strategy. Furthermore, we report our most recent optimization of the synthesis of these new spiropyrazoline oxindoles derivatives and the first preliminary biological results.

Acknowledgements: This work was supported by National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e Ciência) through UID/DTP/04138/2019 (iMed.ULisboa), project PTDC/QUI-QOR/29664/2017, Principal Investigator grant CEECIND/01772/2017 (M. M. M. Santos) and PhD fellowships SFRH/BD/137544/2018 (E.A. Lopes) and SFRH/BD/117931/2016 (M. Espadinha).

¹Ferlay, J., Colombet, M., Soerjomataram, I., Mathers, C., Parkin, D., Piñeros, M., Znaor, A. and Bray, F., Int. J. Cancer, 2019, 144, 1941-1953.

²Espadinha M., Barcherini V., Lopes E. A., Santos M. M. M., Curr. Top. Med. Chem. 2018, 18, 647-660.

³a) Nunes R., Ribeiro C. J. A., Monteiro Â., Rodrigues C. M. P., Amaral J. D., Santos M. M. M., Eur. J. Med. Chem., 2017, 139, 168-179. b) Amaral J. D., Silva D., Rodrigues C. M. P., Solá S., Santos M. M. M., Front. Chem., 2019, 7, article 7