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Non-mutational inactivation of p53 is frequent in acute myeloid leukemia (AML) via overexpression of MDM2. We report that treatment with MI-63, a novel inhibitor of MDM2, activates p53 signaling to induce apoptosis in AML cell lines and primary samples. Cell lines naturally devoid of p53 or expressing shRNA targeting p53 are refractory to apoptosis induction by MI-63, indicating that the effects of MI-63 require p53 expression. MI-63 induced G1 phase arrest and increased p21 expression. MI-63 induced pronounced apoptosis in all primary AML samples tested, and most important, was effective in inducing cell death of leukemia ‘stem’ cells. In addition, MI-63 showed synergy with both doxorubicin and AraC. Interestingly, treatment with MI-63 also led to a reduction in levels of MDM4 protein, a repressor of p53 mediated transcription, in AML cells. Our results warrant investigation of MI-63 or its analogs as anti-leukemic agents, alone or in combination with traditional chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

The diastereoselective preparation of(2S)-2-fluoro-4-[[bis(1,1-dimethylethoxy)phosphinyl]methyl] benzenepropanoic acid(5) is presented as new phosphotyrosyl(pTyr) mimetic suitably protected for incorporation into peptides. Synthesis of 5 utilized electrophilic fluorination under chiral induction provided by the commercially available Evans auxiliary,(S)-(+)-4-phenyl-2-oxazolidinone. In order to demonstrate its synthetic utility, analogue 5 was employed to prepare a signal transduction-directed tripeptide. The design considerations for this peptide and its preliminary biological evaluation are included. [ABSTRACT FROM AUTHOR]