Characterization and over‐expression of chaperonin t‐complex proteins in colorectal cancer

Abstract

The chaperonins are key molecular complexes, which are essential in the folding of proteins to produce stable and functionally competent protein conformations. One member of the chaperonin group of proteins is TCP1 (chaperonin containing t-complex polypeptide 1, or CCT), but little is known about this protein in tumours. In this study, we used comparative proteomic analysis to show that t-complex protein subunits TCP1 beta and TCP1 epsilon are over-expressed in colorectal adenocarcinomas. Monoclonal antibodies to these proteins were developed and the expression and cellular localization of these two proteins in colorectal cancer were analysed by immunohistochemistry on a colorectal cancer tissue microarray. In colorectal cancer, TCP1 beta cellular localization was exclusively cytoplasmic, whereas TCP1 epsilon staining was seen in both the nucleus and the cytoplasm. Both cytoplasmic TCP1 beta and cytoplasmic TCP1 epsilon were significantly over-expressed (p < 0.001 for each protein) in primary colorectal cancer and also showed increased expression with advancing Dukes' stage (p = 0.018 for TCP1 beta and p = 0.045 for TCP1 epsilon). A trend was also identified between over-expression of cytoplasmic TCP1 beta and reduced patient survival (p = 0.05). These results show that both TCP1 beta and TCP1 epsilon are over-expressed in colorectal cancer and indicate a role for TCP1 beta and TCP1 epsilon in colorectal cancer progression.

Characterisation and protein expression profiling of annexins in colorectal cancer

“…Two-dimensional gel electrophoresis and matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS) on normal colon and colorectal cancer were performed as previously described (Lawrie et al, 2004;Dundas et al, 2005;Coghlin et al, 2006). Proteins were solubilised from Dukes C adenocarcinoma tissue samples and patient-matched morphologically normal colorectal mucosa (n ¼ 10 pairs of tumour and normal samples).…”

“…Annexin immunohistochemistry was carried out using a Dako autostainer (Dako, Ely, UK) as previously described Coghlin et al, 2006). Sections (4 mm) of the tissue microarray were dewaxed, rehydrated and an antigen retrieval step performed when required.…”

Global loss of DNA methylation uncovers intronic enhancers in genes showing expression changes

“…Analysis of the 1,366 down-regulated genes showed enrichment for chaperonins ( Figure 6B). Chaperonins, which are involved in protein folding, are overexpressed in cancers [22]; our studies suggest reducing global DNA methylation levels may be a suitable option for reducing the levels of these proteins in cancer cells. However, we note that the expression differences of these genes in response to loss of DNA methylation are modest.…”

Stable isotope dimethyl labeling combined with LTQ mass spectrometric detection, a quantitative proteomics technology used in liver cancer research

“…Coghlin et al (26) reported a high expression of TCP1β and TCP1ε in colon cancer and suggested that TCP1β may be associated with the clinical outcome of colon cancer patients via the use of 2D gel electrophoresis based on biomass spectrum. Iijima et al (27) demonstrated that TCP1α is able to prompt cell proliferation.…”