W19 - WHI HT Proteomic Pilot Study

Investigator Names and Contact Information

Introduction/Intent

Serum from 200 women from the HT trials who did not experience any major trial outcome during WHI follow-up will be studied to identify proteins that change concentration following HT, to identify proteins that change differentially between E and E+P, and to assess the reproducibility of findings between and within proteomic platforms.

Proteomic technologies have great potential to elucidate intervention effects, and to identify early detection and disease risk markers. In 2003 a proteomic colorectal cancer case-control study was proposed but there was concern about lack of preliminary data to show reliability of the protein/peptide measurement platform. In 2004 discussions were held with investigators at NCI (Carl Barrett and others) who expressed interest in a collaborative project. A small-scale proteomic ‘pilot’ study to assess the reliability of proteomic measurements from key platforms, while also providing information of potential value for the interpretation of observed HT effects was formulated. Experience in this initial study may facilitate WHI involvement in larger-scale disease-oriented proteomic studies under BAA or other funding sources

For reasons of cost and study duration, serum samples will be analyzed in pair-marched pools of size 10 (10 randomly selected placebo samples pooled, with corresponding intervention group pool formed from specimens from the corresponding 10 pair-matched women). Two proteomic platforms will be evaluated and compared using the results of the pooled sample analyses as follows:

1. Within platform reliability -- Proteins identified at baseline and at AV1, and their concentrations, will be contrasted for placebo group women, toward assessing reproducibility in a context within which major systematic changes are not expected.

2. Between platform reliability -- Protein concentrations that change differentially from baseline to AV1 between active and placebo groups will be identified for both platforms, and contrasted. Proteins identified will also be contrasted between E+P and E.

Proteomic strategies demonstrating internal reproducibility can be expected to provide many useful leads as to potential mechanistic pathways for the various observed effects of E+P and E, as well as leads for observed differences in effects between E+P and E. After excluding proteins that are deemed biologically implausible, the remainder can be considered as candidate proteins in case-control studies of specific outcomes.

Dual analysis from each serum pool, one on intact proteins (e.g. Wang et al, 2005) that are fractionated and quantitated based on Cy dye labeling, and another based on isotope labeling and shotgun peptide analysis of the same fractions analyzed for intact proteins. These approaches can be expected to rigorously quantify a large number of proteins across a considerable dynamic range.

Results/Findings

See Publications: 843; 921. WHI publications by study lists published WHI papers that have been generated by ancillary studies. A complete list of WHI papers is available in the Papers of this website.

References

Wang H, Clouthier SG, Galchev V, etc, Hanash S. Intact-protein-based high-resolution three-dimensional quantitative analysis system for proteome profiling of biological fluids. Molecular & Cellular Proteomics 2005; 4:618-625.