NF-κB suppression synergizes with E7386, an inhibitor of CBP/β-catenin interaction, to block proliferation of patient-derived colon cancer spheroids.

Dysregulated activation of the WNT/β-catenin signaling pathway is essential for the initiation and development of various cancers. E7386, a small-molecule compound, attenuates WNT signaling by blocking the interaction between β-catenin and CREB-binding protein (CBP); hence, it is regarded as a therapeutic candidate for cancers with activated WNT signaling. In the present study, we evaluated the biological characteristics associated with E7386 sensitivity by using a panel of patient-derived colon cancer spheroids. An integrative approach that combined E7386 sensitivity and gene expression profiles revealed that the resistance of the cancer spheroids to E7386 was associated with the activation of the NF-κB pathway. NF-κB pathway inhibitors acted synergistically with E7386 to block proliferation and induce cell cycle arrest in E7386-resistant spheroids. These findings suggest a possibility that a combination of E7386 and NF-κB inhibition may effectively block the proliferation of a subset of colon cancer cells.