Effect of HPSC-CM on pancreatic tumor cell phenotype. CM from HPSCs (μg/μL) was added to BxPC3 or Panc1 pancreatic tumor cells. A, tumor cell proliferation was measured by MTS assay at 48 h. B, tumor cell invasion was evaluated at 48 h using a modified Boyden chamber assay. C, the ability of tumor cells to form colonies in soft agar was determined at 15 d after addition of HPSC-CM. D, tumor cell proliferation was measured in the presence of conditioned media from nonimmortalized HPSCs. Columns, mean of three experiments. *, P < 0.05 and **, P < 0.005 versus serum-free media (SFM) control. #, P < 0.0005 versus HPSC-CM 1.0 μg/μL.