Different expression of CD44, ICAM-1, and HSP60 on primary tumor and metastases of a human pancreatic carcinoma growing in scid mice.

Surface adhesion molecules play an important, but still not completely clarified, role in tumor metastasization. In this research, FACS analysis was employed to analyze surface expression of CD44H, CD44v5, CD44v6, ICAM-1 and HSP60 in human pancreatic adenocarcinoma cells growing in vitro or collected ex vivo from primary tumors and lung metastases of tumor-engrafted SCID mice. It was found that, in metastatic cells, the standard form of CD44 (CD44H) is down,-regulated, while a large fraction of cells express on membrane the splice variants v5/v6 and, in addition, ICAM-1 and HSP60. It was also apparent that two cell populations are present in lung metastases: a CD44neg population, including cells expressing CD44v5/v6, ICAM-1 and HSP60 and a population of CD44pos, CD44v5/v6neg, ICAM-1neg and HSP60neg cells. These results demonstrate that, in pancreatic adenocarcinomas, metastasization is correlated with expression of the CD44 variants v5 and v6. Moreover, this is the first report demonstrating HSP60 surface expression on metastatic cells.