BackgroundSignificant biochemical changes are observed in glycosaminoglycans in squamous cell laryngeal carcinoma. The most characteristics are in chondroitin/dermatan sulfate fine structure and proportion, which might be due to differential expression of the enzymes involved in their biosynthesis. The aim of the present work was the investigation in expressional and epigenetic level of the enzymes involved in chondroitin/dermatan sulfate biosynthesis in laryngeal cancer.MethodsTissues subjected to total RNA and DNA isolation, and protein extraction. The techniques used in this study were RT-PCR analysis, western blotting and methylation specific PCR.ResultsWe identified that many enzymes were expressed in the cancerous specimens intensively. Dermatan sulfate epimerase was expressed exclusively in the cancerous parts and in minor amounts in healthy tissues; in the macroscopically normal samples it was not detected. Furthermore, chondroitin synthase I and chondroitin polymerizing factor were strongly expressed in the cancerous parts compared to the corresponding normal tissues. Sulfotransferases, like chondroitin 6 sulfotransferase 3, were highly expressed mainly in healthy specimens.ConclusionsThe study of the various chondroitin/dermatan synthesizing enzymes revealed that they were differentially expressed in cancer, in human laryngeal cartilage, leading to specific chondroitin/dermatan structures which contributed to proteoglycan formation with specific features. The expression of the examined enzymes correlated with the glycosaminoglycan profile observed in previous studies.

Abstract. Glycosaminoglycans undergo significant structural alterations in cancer, namely in terms of their sulfation pattern and hydrodynamic size. Numerous studies have focused on this issue, and have demonstrated that glycosaminoglycans play a crucial role in cancer growth and invasion. However, the majority of the enzymes involved in glycosaminoglycan alterations have yet to be examined in detail. The present study focused on the expression of chondroitin-synthesizing enzymes in colorectal cancer. Specimens from healthy controls and cancer patients were subjected to RT-PCR analysis after RNA isolation, and to Western blotting after sequential extraction. The results indicated that chondroitin polymerizing factor and glucuronyltransferase gradually increased with cancer stage, and were expressed at much higher levels in adenomas compared to adjacent normal tissue. The opposite profile was obtained for chondroitin synthase I. Chondroitin synthase III was present at low levels in all the samples examined; however, its expression was higher in the samples from the cancer patients than in those from the healthy controls. It can therefore be concluded that, among the various factors regulating the structure of glycosaminoglycans in cancer, the differential expression of chondroitin-synthesizing enzymes is of the most significance.

Abstract.The glycosaminoglycans are implicated in many processes important in the growth and progression of malignant tumors. In the present study glycosaminoglycans were purified from healthy, macroscopically normal and cancerous specimens of different anatomic sites and different stages of cancer and analyzed by FACE after chondroitinases and sulfatases digestion. The cancerous samples contained increased levels of 6-sulfated unsaturated disaccharides compared to macroscopically normal and healthy samples, the increase being stage-related. The differences in sulfation were found to be related to the anatomic site and the stage of cancer. RT-PCR analysis of 4-sulfotransferase mRNA revealed its presence in decreasing amounts as the stage of the cancer increased. Furthermore, the percent content of hyaluronan disaccharides was elevated in macroscopically normal samples compared to the cancerous, and in addition, it was much more elevated than that of healthy samples. Haluronan levels increase with stage in cancerous tissues. Therefore, it could be concluded that the glycosaminoglycans in colorectal cancer are biosynthetically directed to contribute in different ways depending on the cancer stage and anatomical site.