title: Identification of putative immunologic targets for colon cancer prevention based on conserved gene upregulation from preinvasive to malignant lesions.
abstract: The length of time required for preinvasive adenoma to progress to carcinoma, the immunogenicity of colorectal cancer (CRC), and the identification of high-risk populations make development and testing of a prophylactic vaccine for the prevention of CRC possible. We hypothesized that genes upregulated in adenoma relative to normal tissue, which maintained increased expression in CRC, would encode proteins suitable as putative targets for immunoprevention. We evaluated existing adenoma and CRC microarray datasets and identified 160 genes that were ≥2-fold upregulated in both adenoma and CRC relative to normal colon tissue. We further identified 23 genes that showed protein overexpression in colon adenoma and CRC based on literature review. Silencing the most highly upregulated genes, CDH3, CLDN1, KRT23, and MMP7, in adenoma and CRC cell lines resulted in a significant decrease in viability (P < 0.0001) and proliferation (P < 0.0001) as compared to controls and an increase in cellular apoptosis (P < 0.05 for CDH3, KRT23). Results were duplicated across cell lines representing microsatellite instability, CpG island methylator, and chromosomal instability phenotypes, suggesting immunologic elimination of cells expressing these proteins could impact the progression of all CRC phenotypes. To determine whether these proteins were immunogens, we interrogated sera from early stage CRC patients and controls and found significantly elevated CDH3 (P = 0.006), KRT23 (P = 0.0007), and MMP7 (P < 0.0001) serum immunoglobulin G in cases as compared to controls. These data show a high throughput approach to the identification of biologically relevant putative immunologic targets for CRC and identified three candidates suitable for vaccine development.
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, Seattle, WA 98109, USA. elizabethb@medicine.washington.edu
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Broussard
authors.forename: Rachel
authors.initials: R
authors.lastname: Kim
authors.forename: Jesse C
authors.initials: JC
authors.lastname: Wiley
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Marquez
authors.forename: James E
authors.initials: JE
authors.lastname: Annis
authors.forename: David
authors.initials: D
authors.lastname: Pritchard
authors.forename: Mary L
authors.initials: ML
authors.lastname: Disis
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000378:metabolism / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D015820:Cadherins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D016022:Case-Control Studies; D049109:Cell Proliferation; D062445:Claudin-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000517:prevention & control; D019175:DNA Methylation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053530:Keratins, Type I / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D053842:Microsatellite Instability; D008875:Middle Aged; D009367:Neoplasm Staging; D011230:Precancerous Conditions / Q000175:diagnosis* / Q000378:metabolism / Q000517:prevention & control; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C512197:CDH3 protein, human; C568108:CLDN1 protein, human; D015820:Cadherins; D062445:Claudin-1; C420247:KRT23 protein, human; D053530:Keratins, Type I; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C060932:MMP7 protein, human; D020783:Matrix Metalloproteinase 7