Cardiac muscle troponin T (cTnT)

Cardiac muscle troponin T (cTnT), encoded by the TNNT2 gene, is a structural protein traditionally localized within the sarcomeres of cardiomyocytes, where it plays a critical role in calcium-mediated muscle contraction by anchoring the troponin complex to tropomyosin (UniProt P45379). Recent research has identified that cTnT is ectopically expressed on the external plasma membrane of tumor endothelial cells (TECs) across a variety of solid tumors, including lung, breast, and colon cancers, while remaining absent from the surface of normal vascular endothelium (PubMed: 22964445). This unique surface localization in the tumor microenvironment makes it a highly specific target for vascular-disrupting agents and targeted immunotherapy. Experimental monoclonal antibodies, such as 7E7, have been developed to bind this extracellular cTnT, leading to the selective destruction of tumor blood vessels and subsequent tumor necrosis without affecting normal cardiac tissue, where the protein is sequestered intracellularly (PubMed: 25100373). While cTnT is a well-established clinical biomarker for myocardial injury when released into the bloodstream, its role as a cell-surface target represents a novel therapeutic strategy for inhibiting tumor angiogenesis and growth.

Other names

TNNT2Troponin T type 2Cardiac troponin TCMH2RCM3Ectopic surface cardiac troponin T

Selective binding to ectopically expressed surface cardiac troponin T on tumor endothelial cells to trigger vascular disruption, antibody-dependent cellular cytotoxicity (ADCC), or delivery of cytotoxic payloads.