Clinicopathological significance of expression and amplification of P21-activated kinase 1 gene in colorectal carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the clinicopathological value of the expression and amplification of P21-activated kinase 1 gene (PAK1) in colorectal carcinoma(CRC).</p><p><b>METHODS</b>Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling(TUNEL) methods were used to examine the protein expression, amplification of PAK1 and cell apoptosis in 80 cases of CRC and 30 cases of colorectal adenoma by tissue microarray.</p><p><b>RESULTS</b>IHC showed an overexpression of PAK1 protein in 26% of colorectal adenomas and 62% of CRCs. Significant association was found between expression of PAK1 and tumor histological grade as well as tumor clinical stage(P<0.05). In poor-differentiated(G(3)) CRCs, PAK1 expression in 90% carcinoma was up-regulated, which was significantly higher than that in tumors of G(1/2)(51%). Overexpression of PAK1 was detected in 78% of CRCs in later clinical stages (Dukes C, D), which was significantly higher than that in early clinical stages (Dukes A,B, 53%). In addition, negative correlation between PAK1 overexpression and cell apoptosis was observed in these CRC cohorts(P<0.05). FISH revealed that amplification of PAK1 gene was examined in only 3% CRCs.</p><p><b>CONCLUSIONS</b>Overexpression of PAK1 protein may play an important role in development and progression of colorectal neoplasms and it is closely associated with the malignant histological and invasive phenotype of CRCs. The expression of PAK1 in CRC may be used as one of the new molecular markers in predicting tumors malignant potential and progression.</p>

Screening peptides binding specifically to large intestinal cancer LoVo cells from phage random peptide library / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen the polypeptides specifically binding to human large intestinal cancer LoVo cells from a phage-displayed peptide library for potential use as targeting vectors for large intestinal cancer therapy.</p><p><b>METHODS</b>With the LoVo cells as the target cells and human normal large intestinal mucosal epithelial cells as the absorber cells for subtraction biopanning from a c7c phage-display peptide library, the positive phage clones were identified by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence detection. The amino acid sequences of the identified peptides were deduced by DNA sequencing.</p><p><b>RESULTS</b>After 3 rounds of screening, 5 positive phage clones showing specific binding to LoVo cells and containing conserved motif RPMP were obtained from the 20 randomly selected clones.</p><p><b>CONCLUSION</b>Specific peptide against large intestinal cancer cells can be obtained from a phage-display peptide library for use as potential vectors for targeting therapy of large intestinal cancer.</p>

Expression and amplification of steroid receptor coactivator-3 gene in colorectal carcinoma and its clinicopathological significance / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the expression and amplification of steroid receptor coactivator- 3(SRC- 3) gene in colorectal carcinoma (CRC) and its clinicopathological significance.</p><p><b>METHODS</b>Immunohistochemistry and fluorescence in situ hybridization (FISH) were used to detect the expression and amplification of SRC- 3 gene in CRC, and its association with patient's clinical pathological features was analyzed.</p><p><b>RESULTS</b>A total of 60 patients with CRC were studied. SAR- 3 proteins were overexpressed in 23 cases (38% ). There was a significant association between SAR- 3 overexpression and neoplasm staging (P< 0.01). SRC- 3 protein was overexpressed in 62% of patients with Dukes C or D stage, whereas SRC- 3 protein was normally expressed in 74% of patients with Dukes A or B stage. As for FISH study, 47 cases were informative. High- level amplification of SRC- 3 gene was detected in 6 cases(13% ) and all showed overexpression of SRC- 3 protein. Low- level amplification of SRC- 3 was observed in 9 cases (19% ). Overexpression of SRC- 3 was detected in 6 cases. The remaining 9 of 32 patients(28% ) without amplification of SRC- 3 gene were observed with overexpression of SRC- 3 protein. In addition, 91% patients with CRC were found overexpression of SRC- 3 as well as overexpression of P53.</p><p><b>CONCLUSION</b>The abnormal expression of SRC- 3 gene might impact on the function of P53 and development of CRC. There might exist some unknown mechanisms other than gene amplification of SRC- 3 to regulate its encoded protein expression in CRC.</p>