Nutlin-3b

Nutlin-3b (CAS: 675576-97-3) is the inactive enantiomer of the small molecule Nutlin-3, a known MDM2 inhibitor. Unlike its active counterpart Nutlin-3a, Nutlin-3b exhibits minimal affinity for MDM2—approximately 200-fold lower—and lacks the capacity to stabilize wild-type TP53 or influence cell cycle progression, proliferation, or gene expression associated with TP53 signaling. Nutlin-3b does not induce MDM2, p53, or p21 expression, nor does it affect colony formation in cancer cell lines such as H460. Due to its negligible biological activity, Nutlin-3b serves as a negative control in studies investigating p53–MDM2 interactions and the specific effects of active MDM2 antagonists in cellular and molecular oncology research.

References:
[1] Tovar C, Rosinski J, Filipovic Z, Higgins B, Kolinsky K, Hilton H, Zhao X, Vu BT, Qing W, Packman K, Myklebost O, Heimbrook DC, Vassilev LT. Small-molecule MDM2 antagonists reveal aberrant p53 signaling in cancer: implications for therapy. Proc Natl Acad Sci U S A. 2006 Feb 7;103(6):1888-93.
[2] Cao C, Shinohara ET, Subhawong TK, Geng L, Kim KW, Albert JM, Hallahan DE, Lu B. Radiosensitization of lung cancer by nutlin, an inhibitor of murine double minute 2. Mol Cancer Ther. 2006 Feb;5(2):411-7.