Characterization of insulinlike growth factor I receptors in human colon cancer

摘要: Abstract A possible role of insulinlike growth factor I (IGF-I) and IGF-I receptors in the proliferation human colon cancer has, to best authors' knowledge, not been examined as yet. To determine a cancer, several cell lines cancers were screened for specific binding 125I-IGF-I. Almost all cells variably positive specifically half showed significant response 6.6 nmol/L IGF-I. Dose-dependent effects exogenously added (0.05-3.3 nmol/L) shown representative line (Colo-205). if sites on similar or different from that described other cells, affinity, specificity, molecular size characterized (HCT-116 Colo-205). The optimal assay conditions measuring maximum number 125I-IGF-I vitro, determined found be cells. Scatchard analysis data presence single class high-affinity [disassociation constant (Kd) = approximately 1.0-2.0 nmol/L], with capacity x 10(5) per cell. weight membranes was by gel electrophoresis affinity cross-linked proteins, followed autoradiography. band proteins mass 300 kilodaltons evident under nonreducing separated out into two bands 240 130 reducing conditions. 130-kilodalton represents alpha subunit receptors, 240-kilodalton may represent aggregates receptor subunits reduced completely. widespread existence established freshly resected proliferative effect lines, reflect an important endocrine/paracrine/autocrine regulation situ. (Gastroenterology 1992 Apr;102(4 Pt 1):1101-8)