Distinct high-performance liquid chromatography pattern of transforming growth factor activity in urine of cancer patients as compared with that of normal individuals

Abstract

Reverse-phase high-performance liquid chromatography (HPLC) performed on urine from cancer patients and normal controls revealed the presence of seven chromatographically distinct peaks of transforming growth factor (TGF) activity, as measured by colony formation of normal rat kidney cells in soft agar. Comparison of urines from normal donors and cancer patients showed no differences in EGF (epidermal growth factor)-dependent beta-TGF-like activity but did reveal distinct patterns of EGF-related, EGF-independent alpha-TGF-like activity. All urine samples contained at least two chromatographically distinguishable forms of EGF-dependent TGF activity, eluting from HPLC as broad peaks with 30 and 43% acetonitrile. The remaining five TGFs eluted as sharp peaks with 32, 34, 35, 37, and 38% acetonitrile, demonstrated EGF-competing activity, and thus were functionally related to EGF. Two of the five EGF-related TGFs were consistently elevated only in the urine of cancer patients and eluted with 32% (TGFA) and 37% (TGFD) acetonitrile Two of the other EGF-related TGFs, eluting with 34% (TGFB) and 35% (TGFC) acetonitrile, were commonly found in both normals and cancer patients. The fifth EGF-related TGF, TGFE, eluting with 38% acetonitrile, was found only in normal donor specimens. TGFA corresponded to the unique Mr 30,000 TGF activity previously identified only in the urine of cancer patients. These observations demonstrate that cancer patients produce high levels of EGF-related TGF activities which can be readily distinguished, using reverse-phase HPLC, from EGF-related TGFs produced by normal individuals. Using a solid-phase competitive radioreceptor binding assay for EGF, we demonstrated that quantitation of EGF-competing activity is as sensitive and effective as the soft-agar colony formation assay for distinguishing HPLC profiles of urinary TGF from cancer patients versus that from normal individuals.