New Multiple Myeloma Target Discovered for a Monoclonal Antibody

Finding an appropriate target for new myeloma therapies is not easy, but Japanese myeloma researchers recently announced the discovery of a new antibody that binds to a protein found on the surface on myeloma cells, called CD98 heavy chain (also called SLC3A2). When the monoclonal antibody was used in myeloma mouse models, the antibody prolonged survival.

According to their research published in Science Translational Medicine, the investigators looked outside of traditional "omics" potential targets (genomics, proteomics, metabolomics, metagenomics, and transcriptomics) to look for myeloma-specific markers that can be found on the surface of myeloma cells.

The CD98 heavy chain protein is part of an amino acide transporter. In the mouse testing, they found that even though CD98 heavy chain is located on normal cells, the treatment only bound to the myeloma cells. Differences in a process called glycosylation (adding a sugar molecule to proteins and fatty molecules that change their structure and function) on normal cells vs. myeloma cells could be why the therapy worked on myeloma cells while not touching normal cells. 

CD98 expression on many actively replicating cells and at sites of inflammation suggest that CD98 is involved in cell activtaion and proliferation.

Lead author Kana Hasegawa said: 

"By screening over 10,000 monoclonal antibody clones raised against multiple myeloma cells, we identified R8H283, a monoclonal antibody that recognizes the CD98 heavy chain protein, which is part of an amino acid transporter,"

The monoclonal antibody is called R8H283 and the researchers believe that the CD98 heavy chain target is promising and should be studied further.