Up-regulation of mitochondrial chaperone TRAP1 in ulcerative colitis associated colorectal cancer

AIM:To characterize tumor necrosis factor receptorassociated protein 1(TRAP1)expression in the progression of ulcerative colitis(UC)-associated colorectal cancer.METHODS:Chronic UC is an inflammatory bowel disease that predisposes to colorectal cancer.Immunohistochemical analysis was used to evaluate TRAP1expression on tissue microarrays containing colonic tissues from 42 UC progressors(patients with cancer or dysplasia)and 38 non-progressors(dysplasia/cancer free patients).Statistical analyses of the TRAP1immunohistochemistry staining were performed using Graph Pad Prism.Differences in the TRAP1 level between non-progressors and progressors were tested for statistical significance using the Mann-Whitney test.Receiver operating characteristic curve method was used to quantify marker performance in distinguishing diseased cases from controls.RESULTS:TRAP1 was up-regulated in the colon tissues from UC progressors,but not in the colon tissues from UC non-progressors.Moreover,up-regulation of TRAP1 preceded the neoplastic changes:it was present in both the dysplastic and non-dysplastic tissues of UC progressors.When TRAP1 staining in rectal tissue was used as a diagnostic marker,it could distinguish progressors from non-progressors with 59%sensitivity and 80%specificity.Our study further showed that the increase of TRAP1 expression positively correlated with the degree of inflammation in the colorectal cancer tissues,which could be related to the increased oxidation present in the colonic mucosa from UC progressors.We then investigated the cellular proteome changes underlying oxidative stress,and found that oxidative stress could induce up-regulation of TRAP1 along with several other negative modulators of apoptosis.CONCLUSION:These results suggest that oxidative stress in long standing UC could lead to the increase of cytoprotective protein TRAP1,which in turn could promote cancer progression by preventing or protecting the oxidative damaged epithelial cells from undergoing apoptosis.TRAP1 could be a potential diagnostic marker for UC associated colorectal cancer.

Glycoproteins and glycoproteomics in pancreatic cancer

Aberrations in protein glycosylation and polysaccharides play a pivotal role in pancreatic tumorigenesis, influencing cancer progression, metastasis, immunoresponse and chemoresistance. Abnormal expression in sugar moieties can impact the function of various glycoproteins, including mucins, surface receptors, adhesive proteins, proteoglycans, as well as their effectors and binding ligands, resulting in an increase in pancreatic cancer invasiveness and a cancerfavored microenvironment. Recent advance in glycoproteomics, glycomics and other chemical biology techniques have been employed to better understand the complex mechanism of glycosylation events and how they orchestrate molecular activities in genomics, proteomics and metabolomics implicated in pancreatic adenocarcinoma. A variety of strategies have been demonstrated targeting protein glycosylation and polysaccharides for diagnostic and therapeutic development.

Biomarkers for colitis-associated colorectal cancer

Patients with extensive ulcerative colitis(UC) of more than eight years duration have an increased risk of colorectal cancer. Molecular biomarkers for dysplasia and cancer could have a great clinical value in managing cancer risk in these UC patients. Using a wide range of molecular techniques- including cutting-edge OMICS technologies- recent studies have identified clinically relevant biomarker candidates from a variety of biosamples, including colonic biopsies, blood, stool, and urine. While the challenge remains to validate these candidate biomarkers in multi-center studies and with larger patient cohorts, it is certain that accurate biomarkers of colitis-associated neoplasia would improve clinical management of neoplastic risk in UC patients. This review highlights the ongoing avenues of research in biomarker development for colitis-associated colorectal cancer.