COL1A1 and breast cancer: To further confirm the function of p-CREB in regulating MMP2, ITGB1, and COL1A1, we treated BC cells with KG-501, a small molecule compound that can disrupt phosphor-CREB (Ser-133) binding to the KIX domain of CBP and results in a disrupted CREB-CBP complex, inhibiting CREB-target gene induction.