Lung cancer is the leading cause of cancer death for men and women in the United States, primarily because of late stage diagnosis of non-small cell lung cancer (NSCLC) where there is no curative therapy. Currently there are no reliable biomarkers able to identify early stage disease. We propose to use glycomics, the comprehensive study of all glycans expressed in biological systems, to discover and validate serum-based early detection biomarkers. Glycosylation of tumor proteins is known to change in lung cancer, but it has been difficult to detect these changes in patient samples. Aberrant glycosylated proteins (tumor antigens) are secreted or shed from tumor cells directly into the circulation via tumor vascularization. Recently, methods to profile the serum glycome have been vastly improved due to the emergence of new analytical capabilities of mass spectrometry. Our UC Davis team has pioneered the use of mass spectrometry for analysis of glycans and was among the first to apply its use to profiling glycans isolated from cancer serum samples. The use of these improved methods will make it possible to determine the glycan composition of early and late stage NSCLC in serum samples. Our hypothesis is that sera of NSCLC patients have distinct glycan compositional profiles that can be used to identify potential serum glycan biomarkers of NSCLC. These glycan biomarkers can then be tested and evaluated for use as diagnostic markers of early and late stage NSCLC. We intend to perform glycomic analysis of N-linked oligosaccharides (glycans) isolated from serum samples of patients with NCLCL and compared with those of healthy controls (non-smokers and smokers) using high resolution MALDI FT-ICR mass spectrometry for global analysis of N-linked glycans. A complementary glycomic analysis of the same samples will be performed using nanoLC qTOF tandem mass spectrometry to obtain isomeric, structural and compositional analysis of the N-linked glycans. In addition to the global analysis, two separation techniques will be used to explore deeper into the cancer serum glycome. The serum samples will be depleted of IgG by Protein G affinity chromatography and glycan analysis will be performed on the depleted sera and on the removed IgG. The second separation technique is lectin affinity chromatography to enrich selection of N-linked or O-linked glycosylated proteins for further glycan analysis by MALDI FTICR MS and nanoLC qTOF tandem MS-MS. Then in an expanded clinical study we will determine if glycan profiling can be used to distinguish between patients with early or late stage NSCLC from those with chronic bronchitis or emphysema, conditions of chronic obstructive pulmonary disease (COPD) that have been associated with high risk for NSCLC. Results from this exploratory discovery study can then be used to identify glycan biomarkers for the purpose of developing suitable clinical serum tests for early detection and diagnosis of NSCLC.
Glycomic methods will be developed that are able to molecularly characterize glycoproteins of lung cancer patient samples. Glycan profiles will be produced from sera of individuals with early and late stage lung cancer, COPD, smokers and never smokers, that when compared will identify relevant glycan biomarkers of early stage lung cancer that are distinguishable from late stage and other lung cancer diseases. These glycan profiles can then be used to identify biomarkers of early lung cancer and ultimately be used for early detection of this disease.
| Ruhaak, L Renee; Stroble, Carol; Dai, Jianliang et al. (2016) Serum Glycans as Risk Markers for Non-Small Cell Lung Cancer. Cancer Prev Res (Phila) 9:317-23 |
| Ruhaak, L Renee; Taylor, Sandra L; Miyamoto, Suzanne et al. (2013) Chip-based nLC-TOF-MS is a highly stable technology for large-scale high-throughput analyses. Anal Bioanal Chem 405:4953-8 |
| Ruhaak, L Renee; Nguyen, Uyen Thao; Stroble, Carol et al. (2013) Enrichment strategies in glycomics-based lung cancer biomarker development. Proteomics Clin Appl 7:664-76 |
| Ruhaak, L Renee; Miyamoto, Suzanne; Kelly, Karen et al. (2012) N-Glycan profiling of dried blood spots. Anal Chem 84:396-402 |
| Ruhaak, L Renee; Lebrilla, Carlito B (2012) Advances in analysis of human milk oligosaccharides. Adv Nutr 3:406S-14S |
