The Stimulatory Role of CD300a in Diffuse Large B-Cell Lymphoma

CD300a is a type I transmembrane receptor protein which has shown inhibitory effect on B-cell receptor mediated signals. In an analysis of publicly available data on diffuse large B-cell lymphoma (DLBCL), however, we found that the expression levels of CD300A mRNA were inversely correlated with the overall survival of DLBCL patients. When analyzing the transcript levels of CD300a in human tissues, we found that CD300a mRNA levels were significantly greater in DLBCL tissues than benign lymphoid tissues (P<0.05). To decipher the role of CD300a in DLBCL, we used shRNA system to knock-down the expression levels of CD300a in DLBCL cell lines, and found that decreased levels of CD300a significantly inhibited cell proliferation of OCI-Ly1 cells, but not of VAL, OCI-Ly10 or SUDHL-8 cells. Mechanistically, reduced expression of CD300a resulted in a marked attenuation of Akt phosphorylation in OCI-Ly1 cells. Pharmacologic inhibition of PI3K by LY294002 displayed a similar inhibitory effect on cell proliferation, indicating the possible involvement of PI3K/Akt signaling pathway in CD300a’s effect. Furthermore, using a xenograft animal model, we found that decreasing expression levels of CD300a in OCI-Ly1 cells significantly inhibited tumor formation of these cells in vivo. Collectively, our results suggested a stimulatory role of CD300a in DLBCL which could serve as a potential biomarker and therapeutic target for this malignance.