Objective: To explore the effect of CD99 overexpression on the morphology and differentiation-related phenotypes of classical Hodgkin's lymphoma cell line L428 and investigate the role of CD99 gene in Hodgkin/Reed-Sternberg (HRS) cell generation and transformation.
Methods: The effect of CD99 overexpression on the cell morphology was detected by HE staining and phalloidin staining. Differentiation-related protein expressions were detected by immunocytochemistry and flow cytometry after stable transfection of CD99 gene in L428 cells.
Results: CD99 overexpression caused a decrease of the cell size and reorganization of the actin cytoskeleton in L428 cells. Upregulation of CD99 led to the loss of classical Hodgkin's lymphoma diagnosis marker CD30 and CD15 and the restoration of the B-cell makers of PAX5, CD19, CD79α, BCL-6, and CD10.
Conclusion: CD99 overexpression leads to redifferentiation of L428 cells towards B cells, suggesting that the loss of B-cell phenotype in classical Hodgkin's lymphoma is very likely a result of down-regulated CD99 expression.