Mining serum for a lipolysis factor

Abstract

Cancer cachexia provides a unique model to identify blood‐borne factors that promote lipolysis. Using the MCA‐induced sarcoma model to study cancer‐related cachexia, we have shown that known lipolytic molecules cannot account for the major loss of lipid observed. Our goal is to isolate this factor biochemically from serum of tumor‐bearing rats using the lipid release activity from 3T3‐L1 adipocytes. Initial characterization studies have established that the factor is a protein with a molecular weight > 30 kDa. The current purification strategy includes: 1) bulk anion exchange chromatography on DEAE cellulose with a step gradient to remove highly abundant serum proteins; 2) analytical high performance anion exchange chromatography on MonoQ; and 3) analytical high performance size fractionation on Superdex 200. Results of the development of this purification protocol, progress toward identification of the novel lipolysis factor, and properties of the active species will be reported. This scheme shows that the lipolytic factor we seek is stable and can be identified via multiple chromatographic steps. Supported by a grant from: American Institute for Cancer Research