ALDH+ Anaplastic Thyroid Cancer Cells Show Vulnerability to a Pharmacologic Inducer of Centrosome Declustering.

Excessive centrosome activation is detrimental to normal cells by hampering bipolar spindle formation during mitosis and inducing cell death. In the highly aggressive anaplastic thyroid cancer (ATC), cells expressing the aldehyde dehydrogenase-positive (ALDH+) stem cell trait are enriched in supernumerary centrosomes and tolerate centrosome amplification, which offers these cells a growth advantage. Our earlier work characterized the chromosomal instability (CIN) within this cell population, which was due to dysfunctional centrosomes manifesting as a deficiency in pericentriolar material. Here, we report a novel 2-4-morpholinoanilino-6-[(2-exo-norbornyl) amino]-purine (MEAP) that preferentially restores centrosome microtubule nucleation activity in centrosome-deficient ALDH+ ATC cells. Exposure of these cells to MEAP induced pericentriolar accumulation and microtubule nucleation activity of supernumerary centrosomes, resulting in spindle multipolarity. Consequently, MEAP was capable of preferentially eliminating ALDH+ ATC cell population, thus reducing cell spherogenesis and self-renewal capacity. In a preclinical ATC mouse model, MEAP preferentially eliminated ALDH+ cell clusters, increased the rate of spindle multipolarity, decreased CIN, and generated a robust antitumor response. Lastly, we identified that the selective activity of MEAP in ALDH+ cells involved the modulation of NEDD9-STAT3 signaling. Together, these findings support the potential of targeting centrosome amplification as an alternative therapeutic approach for aggressive ALDH+ cancers failing first-line therapeutics. SIGNIFICANCE: This study identifies MEAP as the first selective vulnerability of ALDH+ ATC stem cells, their dysfunctional supernumerary centrosomes. Unlike broad chemotherapeutics, MEAP exploits this cancer-specific centrosome amplification by paradoxically hyperactivating them via NEDD9-STAT3 disruption, forcing multipolar mitosis and ALDH+ elimination while sparing bulk tumor cells. Validates centrosome declustering as a novel therapeutic axis for aggressive, stem-like cancers failing standard therapies, with robust in vivo efficacy and a mechanistic framework (NEDD9-STAT3-centrosome axis) for precision translation.