Recent progress in antitumor functions of the intracellular antibodies

Conventional antibodies used for cancer therapies can only target the extracellular epitopes of tumor-associated antigens (TAAs); however, they struggle to enter cancer cells to interact with intracellular TAAs. Intrabodies are the engineered single-chain antibodies that can be transferred to the living cells or expressed within the cells and target the intracellular TAAs, owing to their nanosizes, enhanced motility and specific and potent binding affinities for the TAAs. Intrabody-based technology is a supplement to the current gene silencing technologies that can regulate a variety of biochemical processes and cellular functions and could be applicable for clinical treatment of tumors. Here, we review the development and current status of the intrabodies for the targeted treatment of cancers.