Background:

MI-773 (SAR405838) is a specific antagonist of MDM2 with Ki value of 0.88 nM [1].

Murine double minute 2 (MDM2) is a primary negative regulator of wild-type p53, which is a tumor suppressor. MDM2 is an E3 ubiquitin ligase that induces p53 degradation and blocks the p53 trans-activation domain (TAD) [1].

MI-773 (SAR405838) is a MDM2 antagonist. MI-773 (SAR405838) inhibited cells growth in SJSA-1, RS4;11, LNCaP and HCT-116 cancer cell lines with IC50 values of 0.092, 0.089, 0.27 and 0.20 μM, respectively. MI-773 (SAR405838) exhibited high selectivity over cancer cell lines with mutated or deleted p53 with IC50 values of >20, >10, >10 and >10 μM for HCT-116 (p53-/-), SAOS-2, PC-3 and SW620 cancer cell lines, respectively [1].

In mice bearing the SJSA-1, HCT-116, RS4;11, and LNCaP xenograft tumors, MI-773 (SAR405838) increased the levels of MDM2, p21 and p53 proteins in a dose- and time-dependent way and induced apoptosis. In the SJSA-1 xenograft model, MI-773 (SAR405838) (30-100 mg/kg) induced tumor regression and significantly inhibited tumor growth [1].

Reference:
[1].  Wang S, Sun W, Zhao Y, et al. SAR405838: an optimized inhibitor of MDM2-p53 interaction that induces complete and durable tumor regression. Cancer Res, 2014, 74(20): 5855-5865.