Altered gene expression profiles define pathways in colorectal cancer cell lines affected by celecoxib

It is well established that celecoxib, a selective inhibitor of cyclooxygenase-2 (COX-2) and a tested chemopreventive agent, has several COX-2-independent activities. In an attempt to better understand COX-2-independent molecular mechanisms underlying the chemopreventive activity of celecoxib, we did global transcription profiling of celecoxib-treated COX-2-positive and COX-2-deficient colorectal cancer cell lines. Celecoxib treatment resulted in significantly altered expression levels of over 1,000 to 3,000 transcripts in these cell lines, respectively. A pathway/functional analysis of celecoxib-affected transcripts, using Gene Ontology and Biocarta Pathways and exploring biological association networks, revealed that celecoxib modulates expression of numerous genes involved in a variety of cellular processes, including metabolism, cell proliferation, apoptotic signaling, cell cycle check points, lymphocyte activation, and signaling pathways. Among these processes, cell proliferation and apoptotic signaling consistently ranked as the highest-scoring Gene Ontology terms and Biocarta Pathways in both COX-2 expresser and nonexpresser cell lines. Altered expression of many of the genes by celecoxib was confirmed by quantitative PCR and at the protein level by Western blotting. Many novel genes emerged from our analysis of global transcription patterns that were not previously reported to be affected by celecoxib. In the future, in-depth work on selected genes will determine if these genes may serve as potential molecular targets for more effective chemopreventive strategies

Plasma Proteomic Profiling: Search for Lung Cancer Diagnostic and Early Detection Markers

Environmental and occupational exposure to asbestos is among the established risk factors for lung cancer, the leading cause of cancer-related deaths in the United States. This link between exposure to asbestos and the excessive death rate from lung cancer was evident in a study of former workers of an asbestos pipe insulation manufacturing plant in Tyler, TX. We performed comparative proteomic profiling of plasma samples that were collected from nine patients within 12 months before death and their age-, race- and exposure-matched disease-free controls on strong anion exchange chips using surface-enhanced laser desorption ionization time-of-flight mass spectrometry. A distance-dependent K-nearest neighbor (KNN) classification algorithm identified spectral features of m/z values 7558.9 and 15103.0 that were able to distinguish lung cancer patients from disease-free individuals with high sensitivity and specificity. The high correlation between the intensities of these two peaks (r=0.987) strongly suggests that they are the doubly and singly charged ions of the same protein product. Examination of these proteomic markers in the plasma samples of subjects from \u3e5 years before death from lung cancer suggested that they are related to the early development of lung cancer. Validation of these biomarkers would have significant implications for the early detection of lung cancer and better management of high-risk patients

Protective effect of Cox-2 allelic variants on risk of colorectal adenoma development in African Americans

BACKGROUND: Recent evidence indicates that single nucleotide polymorphisms (SNPs) in the Cox-2 gene may modulate the risk of colorectal adenoma development. PATIENTS AND METHODS: We explored possible associations between Cox-2 polymorphisms and risk of adenoma development in an African American case-control study comprising 72 cases of advanced adenomas and 146 polyp-free controls. An exhaustive approach of genotyping 13 haplotype-tagging SNPs (ht SNPs) distributed over the entire COX-2 gene was used. RESULTS: Statistically significant inverse associations were observed between the heterozygous genotypes at the 5229 G\u3eT polymorphism in intron 5 [odds ratio (OR)=0.42; confidence interval (CI)=0.19-0.92; p=0.03] and at the 10935 A\u3eG polymorphism in the 3\u27 flanking region downstream from the poly A signals (OR=0.39; CI=0.18-0.83;p=0.01) and the risk for colorectal adenoma development. CONCLUSION: The data from our pilot study suggest that allelic variants of the COX-2 gene significantly influence the risk of adenoma development in the African American population