Extracellular matrix does not induce the proliferation, but promotes the differentiation, of Hodgkin's cell line HDLM-1.

Tumor cells from the Hodgkin's cell line HDLM-1 were cultured in extracellular matrix (ECM)-coated flasks. Within 24 hours, the cells underwent rapid differentiation, accompanied by morphologic and phenotypic changes. A slow and less prominent, but similar change was observed in HDLM-1 cells after they had been induced with phorbol ester for 5 days. The ECM-induced cells became HeFi-1-negative and expressed antigens 2H9 and 1E9 on their nuclear membranes. These cells had punctate acid-phosphatase and esterase activities. Approximately 70% of the ECM-induced cells were elongated and had long, blunt cytoplasmic projections. These findings, together with evidence the authors previously presented, indicate that H-RS cells are related to interdigitating reticulum cells. The authors believe that the ECM-induced HDLM-1 cells can be used as an important model for studies of the nature and cell lineage of Hodgkin's disease.