Detection and Analysis of Calcitonin Species Produced by Small Cell Lung Cancer

Abstract

The work described in this thesis covers the development of an HPLC method that enables the simultaneous detection of CT, CTG, CTGK, and CTGKK from DMS-53 cell growth medium and cell lysate. This method was used to discover that DMS-53 cells produced the novel glycopeptides gCT and gCTG. Isolation of these compounds enabled analysis using various forms of mass spectroscopy to completely characterise both gCT and gCTG.

The detection method was utilised along with PHM and CPE inhibitors to investigate CT biosynthesis with the intent to limit CT production. It was found that gCT biosynthesis takes place via a parallel biosynthetic pathway that allows for CT to bypass inhibitory effects by altering the regulation between the two pathways. Additionally it was found that, in the face of interrupted CT biosynthesis, the maintenance of intracellular CT is the first priority of DMS-53 cells. Combined, this helps CT remain insulated from the effects of outside regulation. The CPE inhibitor GEMSA was shown to successfully lower extracellular CTG and gCTG levels however dosed samples exhibited an increase in extracellular CT and gCT. Show more