mln-8237 and Colonic-Neoplasms

Aurora kinases (AURKs) are mitotic kinases important for regulating cell cycle progression. Small-molecule inhibitors of AURK have shown promising antitumor effects in multiple cancers; however, the utility of these inhibitors as inducers of cancer cell death has thus far been limited. Here, we examined the role of the Bcl-2 family proteins in AURK inhibition-induced apoptosis in colon cancer cells. We found that alisertib and danusertib, two small-molecule inhibitors of AURK, are inefficient inducers of apoptosis in HCT116 and DLD-1 colon cancer cells, the survival of which requires at least one of the two antiapoptotic Bcl-2 family proteins, Bcl-xL and Mcl-1. We further identified Bcl-xL as a major suppressor of alisertib- or danusertib-induced apoptosis in HCT116 cells. We demonstrate that combination of a Bcl-2 homology (BH)3-mimetic inhibitor (ABT-737), a selective inhibitor of Bcl-xL, Bcl-2, and Bcl-w, with alisertib or danusertib potently induces apoptosis through the Bcl-2 family effector protein Bax. In addition, we identified Bid, Puma, and Noxa, three BH3-only proteins of the Bcl-2 family, as mediators of alisertib-ABT-737-induced apoptosis. We show while Noxa promotes apoptosis by constitutively sequestering Mcl-1, Puma becomes associated with Mcl-1 upon alisertib treatment. On the other hand, we found that alisertib treatment causes activation of caspase-2, which promotes apoptosis by cleaving Bid into truncated Bid, a suppressor of both Bcl-xL and Mcl-1. Together, these results define the Bcl-2 protein network critically involved in AURK inhibitor-induced apoptosis and suggest that BH3-mimetics targeting Bcl-xL may help overcome resistance to AURK inhibitors in cancer cells.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Aurora Kinases; bcl-2-Associated X Protein; bcl-X Protein; Cell Line, Tumor; Colonic Neoplasms; Enzyme Activation; HCT116 Cells; Humans; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2

Neuroendocrine (NE) cancers are a diverse group of neoplasms typically diagnosed and treated on the basis of their site of origin. This Perspective focuses on advances in our understanding of the tumorigenesis and treatment of poorly differentiated neuroendocrine tumors. Recent evidence from sequencing indicates that, although neuroendocrine tumors can arise de novo, they can also develop as a result of lineage plasticity in response to pressure from targeted therapies. We discuss the shared genomic alterations of these tumors independently of their site of origin, and we explore potential therapeutic strategies on the basis of recent biological findings.

Topics: Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Azepines; Benzodiazepines; Carcinogenesis; Carcinoma, Neuroendocrine; Carcinoma, Small Cell; Cell Differentiation; Cell Lineage; Cell Plasticity; Colonic Neoplasms; Disease Progression; Epigenesis, Genetic; Esophageal Neoplasms; Female; Head and Neck Neoplasms; Humans; Lung Neoplasms; Male; Molecular Targeted Therapy; Neoplasms, Glandular and Epithelial; Neuroendocrine Tumors; Ovarian Neoplasms; Prostatic Neoplasms; Proto-Oncogene Proteins c-met; Proto-Oncogene Proteins c-myc; Pyrimidines; Retinoblastoma Binding Proteins; Triazoles; Tumor Suppressor Protein p53; Ubiquitin-Protein Ligases; Urinary Bladder Neoplasms; Uterine Cervical Neoplasms