CONCLUSIONS: This new animal cell line may be a useful model to study the effect of growth factors on malignant cell proliferation and differentiation in both in vivo and in vitro systems. METHODS: We established a new pancreatic cancer cell line from pancreatic cancer in the hamster (HPC) induced by N-nitrosobis(2-oxopropyl)amine (BOP) and characterized its morphological, pathological, and biological patterns. RESULTS: Cells grew rapidly, with a doubling time of 22.5 h. Chromosome number ranged from 33 to 144, and flow cytometric analysis showed two peaks of DNA distribution as a proliferative pattern. Ultrastructural analyses using transmission and scanning electron microscopy of HPC cells revealed desmosomes and loose interdigitation, with pseudopods and microvilli on the cell surface. The overexpression of epidermal growth factor (EGF) receptors on HPC cells was shown by immunohistochemistry. Binding characteristics and biological activity of EGF and type alpha transforming growth factor (TGF-alpha) were studied. TGF-alpha stimulated DNA synthesis in a dose-dependent manner, whereas EGF was without effect. Scatchard analysis of 125I-EGF binding data at pH 7.4 indicated the presence of two orders of binding sites, where that of 125I-TGF-alpha showed only a single order. Regarding the effect of pH on 125I-EGF or 125I-TGF-alpha dissociation, one-half maximal dissociation of 125I-EGF or 125I-TGF-alpha occurred at pH 6.0 or 6.5, respectively. Characteristics of the EGF receptor are similar to those of cultured human pancreatic cancer cells.
CONCLUSIONS: This new animal cell line may be a useful model to study the effect of growth factors on malignant cell proliferation and differentiation in both in vivo and in vitro systems. METHODS: We established a new pancreatic cancer cell line from pancreatic cancer in the hamster (HPC) induced by N-nitrosobis(2-oxopropyl)amine (BOP) and characterized its morphological, pathological, and biological patterns. RESULTS: Cells grew rapidly, with a doubling time of 22.5 h. Chromosome number ranged from 33 to 144, and flow cytometric analysis showed two peaks of DNA distribution as a proliferative pattern. Ultrastructural analyses using transmission and scanning electron microscopy of HPC cells revealed desmosomes and loose interdigitation, with pseudopods and microvilli on the cell surface. The overexpression of epidermal growth factor (EGF) receptors on HPC cells was shown by immunohistochemistry. Binding characteristics and biological activity of EGF and type alpha transforming growth factor (TGF-alpha) were studied. TGF-alpha stimulated DNA synthesis in a dose-dependent manner, whereas EGF was without effect. Scatchard analysis of 125I-EGF binding data at pH 7.4 indicated the presence of two orders of binding sites, where that of 125I-TGF-alpha showed only a single order. Regarding the effect of pH on 125I-EGF or 125I-TGF-alpha dissociation, one-half maximal dissociation of 125I-EGF or 125I-TGF-alpha occurred at pH 6.0 or 6.5, respectively. Characteristics of the EGF receptor are similar to those of cultured humanpancreatic cancer cells.