CEACAM6

Class

antibody-enzyme (urease) immunoconjugate

Pathway

CEACAM6-targeted delivery of urease enzyme causing local tumor microenvironment alkalinization

CEACAM6 (carcinoembryonic antigen-related cell adhesion molecule 6) is a cell-surface glycoprotein anchored to the plasma membrane via a glycosylphosphatidylinositol (GPI) linkage. It is expressed at low levels in normal epithelium but markedly elevated on the surface of many solid tumor cells, including those of the lung, pancreas, and colon. Its overexpression is associated with enhanced tumor cell adhesion, invasion, and resistance to normal growth-regulatory signals, making it useful for distinguishing malignant from healthy tissue. Because CEACAM6 is displayed abundantly and selectively on tumor cell surfaces, it can serve as a docking site for an antibody engineered to deliver a therapeutic payload directly to the tumor microenvironment. In this mechanism, the antibody carries a conjugated enzyme, urease, which catalyzes the breakdown of urea into ammonia and carbon dioxide. This reaction raises local pH, counteracting the acidification that characteristically develops within solid tumors as a byproduct of their altered, glycolysis-dominant metabolism (the Warburg effect). Tumor acidity is thought to favor invasion, suppress local immune activity, and reduce the effectiveness of many chemotherapeutic agents; reversing it locally is proposed as a way to make the tumor microenvironment less hospitable to cancer progression, a rationale relevant broadly across CEACAM6-overexpressing solid tumors such as lung and pancreatic cancer.