The online version of this article has a supplementary appendix.Background C-type lectin-like molecule-1 is a transmembrane receptor expressed on myeloid cells, acute myeloid leukemia blasts and leukemic stem cells. To validate the potential of this receptor as a therapeutic target in acute myeloid leukemia, we generated a series of monoclonal antibodies against the extracellular domain of C-type lectin-like molecule-1 and used them to extend the expression profile analysis of acute myeloid leukemia cells and to select cytotoxic monoclonal antibodies against acute myeloid leukemia cells in preclinical models.
Design and MethodsC-type lectin-like molecule-1 expression was analyzed in acute myeloid leukemia cell lines, and in myeloid derived cells from patients with acute myeloid leukemia and healthy donors. Anti-C-type lectin-like molecule-1 antibody-mediated in vitro cytotoxic activity against acute myeloid leukemia blasts/cell lines and in vivo anti-cancer activity in a mouse xenograft model were assessed. Internalization of C-type lectin-like molecule-1 monoclonal antibodies upon receptor ligation was also investigated. -stem cells, but not in acute lymphoblastic leukemia blasts (n=5). Selected anti-C-type lectin-like molecule-1 monoclonal antibodies mediated dose-dependent complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity specifically against acute myeloid leukemiaderived cell lines. Exogenous expression of the transmembrane receptor in HEK293 cells rendered the cells susceptible to antibody-mediated killing by monoclonal antibodies to the receptor. Furthermore, these monoclonal antibodies demonstrated strong complement-dependent cytotoxicity against freshly isolated acute myeloid leukemia blasts (15/16 cases; 94%). The monoclonal antibodies were efficiently internalized upon binding to Ctype lectin-like molecule-1 in HL-60 cells. Moreover, a lead chimeric C-type lectin-like molecule-1 monoclonal antibody reduced the tumor size in xenograft mice implanted with HL-60 cells.
ConclusionsOur results demonstrate that targeting C-type lectin-like molecule-1 with specific cytotoxic monoclonal antibodies is an attractive approach which could lead to novel therapies for acute myeloid leukemia.Key words: C-type, lectin-like molecule-1, immunotherapy, acute myeloid leukemia.Citation: Zhao X, Singh S, Pardoux C, Zhao J, Hsi ED, Abo A, and Korver W. Targeting C-type lectin-like molecule-1 for antibody-mediated immunotherapy in acute myeloid leukemia. Haematologica. 2010;95:71-78. doi:10.3324/haematol.2009 This is an open-access paper.Targeting C-type lectin-like molecule-1 for antibody-mediated immunotherapy in acute myeloid leukemia