apr-246 and Colorectal-Neoplasms

PRIMA-1Met is the methylated PRIMA-1 (p53 reactivation and induction of massive apoptosis) and could restore tumor suppressor function of mutant p53 and induce p53 dependent apoptosis in cancer cells harboring mutant p53. However, p53 independent activity of PRIMA-1Met remains elusive. Here we reported that PRIMA-1Met attenuated colorectal cancer cell growth irrespective of p53 status. Kinase profiling revealed that mitogen-activated or extracellular signal-related protein kinase (MEK) might be a potential target of PRIMA-1Met. Pull-down binding and ATP competitive assay showed that PRIMA-1Met directly bound MEK in vitro and in cells. Furthermore, the direct binding sites of PRIMA-1Met were explored by using a computational docking model. Treatment of colorectal cancer cells with PRIMA-1Met inhibited p53-independent phosphorylation of MEK, which in turn impaired anchorage-independent cell growth in vitro. Moreover, PRIMA-1Met suppressed colorectal cancer growth in xenograft mouse model by inhibiting MEK1 activity.Taken together, our findings demonstrate a novel p53-independent activity of PRIMA-1Met to inhibit MEK and suppress colorectal cancer growth.

Topics: Animals; Antineoplastic Agents; Cell Proliferation; Colorectal Neoplasms; Dose-Response Relationship, Drug; HCT116 Cells; HT29 Cells; Humans; MAP Kinase Kinase 1; MAP Kinase Kinase Kinases; Mice, Nude; Molecular Docking Simulation; Phosphorylation; Protein Binding; Protein Kinase Inhibitors; Quinuclidines; Signal Transduction; Time Factors; Tumor Burden; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays

PRIMA-1met (APR-246) is a methylated derivative and structural analog of PRIMA-1 (p53 re-activation and induction of massive apoptosis). PRIMA-1met has been reported to restore both the wild type (wt) structure and function of mutant p53. Here, we show that PRIMA-1met is highly effective at limiting the growth of CRC cells regardless of p53 status. However, PRIMA-1met induces robust apoptosis only in CRC cells with mutant p53. Upregulation of Noxa, a proapoptotic molecule, is crucial for PRIMA-1met mediated activity. In human xenograft model of disease, PRIMA-1met effectively suppresses CRC tumor growth. Our results uncover distinct mechanisms of PRIMA-1met in CRC with different p53 status, thus providing a mechanistic rationale to evaluate the clinical efficacy of PRIMA-1met in CRC patients with different p53 status.

Topics: Animals; Caco-2 Cells; Cell Proliferation; Colorectal Neoplasms; Disease Models, Animal; HT29 Cells; Humans; Mice; Mice, Inbred NOD; Mice, SCID; Quinuclidines; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays