ABSTRACT
Objective:To screen the key exosomal long non-coding RNAs (lncRNAs) molecules that cause nasopharyngeal carcinoma cells to develop chemoradiotherapy resistance.Methods:In vitro, a model of concurrent chemoradiotherapy for human nasopharyngeal carcinoma cells was constructed, and the continuous shock method of high-dose concurrent chemoradiotherapy was used to induce the establishment of chemoradiotherapy-resistant nasopharyngeal carcinoma cell lines, and its resistance formation was verified. Exosomes produced by chemoradiotherapy-resistant cell lines and respective mother cell lines for nasopharyngeal carcinoma were extracted and identified. Finally, biochip technology was used to detect the differential expression levels of exosomal lncRNAs. Results:After 10 repeated treatments of concurrent chemoradiotherapy, CNE-1 CRR and CNE-2 CRR were successfully obtained. Compared with the mother cell lines, CNE-1 CRR and CNE-2 CRR had a tendency to transform from epithelial to interstitial morphology, and the number of cell clones was higher, and the values of average lethal dose (D 0), quasi-threshould dose (D q), survival fraction after 2 Gy irradiation (SF 2) and cell survival rate were higher. Nasopharyngeal carcinoma cells were detected by PCR chip of exosomal lncRNAs. Compared with their respective mother cell lines, 18 lncRNAs in CNE-1 CRR exosomes were significantly up-regulated and 31 lncRNAs were significantly down-regulated, and 15 lncRNAs were significantly up-regulated and 38 lncRNAs were significantly down-regulated in CNE-2 CRR exosomes. CNE-1 CRR also had similar expression profiles to CNE-2 CRR. Conclusion:There are significantly up-regulated and down-regulated lncRNAs in the exosomes of CNE-1 CRR and CNE-2 CRR.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the application of mismatch repair (MMR) genes proteins expression to screen for Lynch syndrome in colorectal cancer patients.</p><p><b>METHODS</b>One hundred consecutive colorectal cancers cases collected from 2012 to 2013 were tested immunohistochemically for the protein expression of MLH1, MSH2, MSH6 and PMS2, and also by the ARMS method for the mutation status of BRAF genes in those cases lacking protein expression for MLH1.</p><p><b>RESULTS</b>The result of MMR immunocytochemistry showed that nine of 100 cases lacked MMR protein expression, including three cases each that were MLH1-/PMS2- and MSH2-/MSH6- respectively, two cases were MLH6- and one case was PMS2-; overall, the majority of these cases lacked protein expression of MLH1 and MSH2. The BRAF genes mutation test showed one case of mutation, indicating that the patient might have MLH1 gene methylation as a result of the mutation of BRAF genes, and that was a sporadic case. The age of onset for patients lacking MMR protein expression was lower than patients with sporadic colorectal cancer (P = 0.011). Colorectal cancers associated with the lack of MMR protein expression mostly occurred in the right colon (P = 0.001), and histomorphologically were often accompanied by mucinous adenocarcinoma (P = 0.010) and tumor lymphocytic infiltration.</p><p><b>CONCLUSION</b>Immunohistochemical staining for MMR proteins in patients with colorectal cancer, accompanied by testing for BRAF genes mutation, may be an effective approach to screen for Lynch syndrome.</p>