Tumor cell ligands for NK activating receptors and death receptors

This category encompasses a diverse group of cell surface proteins expressed by tumor cells that serve as triggers for anti-tumor effector mechanisms [1]. Tumor cell ligands for Natural Killer (NK) activating receptors, such as MICA, MICB, and ULBP family members, bind to receptors like NKG2D on NK cells and T cells to stimulate cytotoxic responses [2]. These ligands are often upregulated in response to cellular stress, DNA damage, or oncogenic transformation, marking cells for immune destruction [2]. Death receptors, including TRAIL-R1 (DR4) and TRAIL-R2 (DR5), are members of the tumor necrosis factor receptor superfamily that, upon ligation by TRAIL or agonistic antibodies, initiate the extrinsic apoptotic pathway leading to programmed cell death [1][4]. Therapeutic strategies targeting these molecules include agonistic antibodies designed to induce apoptosis directly in cancer cells or monoclonal antibodies that prevent the proteolytic shedding of NK ligands [3]. Additionally, bispecific innate cell engagers and CAR-NK therapies are being developed to enhance the recognition of these ligands on the tumor surface [2]. A major challenge in targeting these molecules is the phenomenon of ligand shedding, where tumor cells release soluble forms of ligands like MICA to decoy and downregulate immune receptors [3]. Clinical trials have explored various agonists and antibodies, though efficacy has often been limited by short half-lives, tumor resistance mechanisms, and potential hepatotoxicity [4].

Other names

NKG2D ligandsDeath receptorsPro-apoptotic receptorsTRAIL receptorsStress-induced ligands

Agonism of death receptors to trigger the extrinsic apoptotic pathway and engagement of NK cell activating receptors to promote immune-mediated tumor lysis.