Heparan sulfate proteoglycans undergo differential expression alterations in left sided colorectal cancer, depending on their metastatic character

Abstract

BackgroundHeparan sulfate proteoglycans (HSPGs) are complex molecules which play a role in the invasion and growth and metastatic properties of cancerous cells. In this work we analyze changes in the patterns of expression of HSPGs in left sided colorectal cancer (LSCRC), both metastatic and non-metastatic, and the results are also compared with those previously obtained for right sided tumors (RSCRCs).MethodsEighteen LSCRCs were studied using qPCR to analyze the expression of both the proteoglycan core proteins and the enzymes involved in heparan sulfate chain biosynthesis. Certain HSPGs also carry chondroitin sulfate chains and so we also studied the genes involved in its biosynthesis. The expression of certain genes that showed significant expression differences were also analysed using immunohistochemical techniques.ResultsChanges in proteoglycan core proteins were dependent on their location, and the main differences between metastatic and non-metastatic tumors affected cell-surface glypicans, while other molecules were quite similar. Glypicans were also responsible for the main differences between RS- and LS- malignances. Regarding the biosynthesis of heparan sulfate chains, differential alterations in transcription depending on the presence or not of metastasis affected genes involved in the modification of uronic acid (epimerization and 2-O sulfation), and some isoforms responsible for sulfation of glucosamine (NDST1, HS6ST1). Moreover, in RSCRCs differences were preferentially found in the expression of genes involved in C6 and C3 sulfation of glucosamine, but not in NDSTs or SULFs. Finally, synthesis of chondroitin sulfate showed some alterations, which affected various steps, including polimerization and the modification of chains, but the main variations dependent on the presence of metastases were epimerization and 6C sulfation; however, when compared with RSCRCs, the essential divergences affected polymerization of the chains and the 6C sulfation of the galactosamine residue.ConclusionsWe evidenced alterations in the expression of HSPGs, including the expression of cell surface core proteins, many glycosiltransferases and some enzymes that modify the GAG chains in LSCRCs, but this was dependent on the metastatic nature of the tumor. Some of these alterations are shared with RSCRCs, while others, focused on specific gene groups, are dependent on tumor localization.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-4597-x) contains supplementary material, which is available to authorized users.

Heparan Sulfate Proteoglycan Signaling in Tumor Microenvironment

“…The alterations in the expression levels of HSPGs depend on their location and may represent a hallmark of the metastatic or non-metastatic nature of the tumor. For example, while SDC1 results in being overexpressed in left-sided colorectal tumors independently from the presence of metastasis, it results in being upregulated only in metastatic right-sided colorectal cancers [31,105]. However, a significant reduction of cell surface tethered SDC1 and an increase of shed SDC1 in the ECM has been observed as a function of tumor progression and aggressiveness, suggesting the involvement of post-transcriptional mechanisms in SDC1 expression in this type of tumor.…”

“…Altered expression and structural variability of HSPGs have been associated with an extensive remodeling of tumor microenvironment where HSPGs not only contribute to the formation of a structural framework for tumor growth but are also involved in the regulation of cell-matrix and cell-cell interactions, and cell signaling [29][30][31][32][33][34][35]. They are able to modulate cancer cell phenotype, the development of drug resistance, and tumor stroma angiogenesis [36][37][38][39][40][41].…”

“…The genetic loss of NDST4, a member of the N-deacetylase/N-sulfotransferase (NDST) family, correlates with an advanced pathological stage and poor survival in colorectal carcinomas [46]. Interestingly, depending on the metastatic nature of the tumor and its localization, differential expression in the transcription of genes involved in the epimerization and sulfation of uronic acid, and glucosamine sulfation were detected in left-and right-sided colorectal cancers [31]. Defective HS-3-O-sulfation due to methylation-associated repression of HS glucosamine 3-O-sulfotransferase gene (3-OST) results in being associated with chondrosarcoma progression [47], whereas hypermethylation of the 3-OST gene is associated with poor survival in non-small cell lung cancer [48].…”

“…While CPG3 results in being overexpressed in liver cancer, lung squamous cell carcinoma, neuroblastoma, ovarian cancer, testicular germ cell tumor, thyroid cancer, yolk sac tumor and other cancers, reduced levels of GPC3 have been found in breast cancer, colorectal cancer, mesothelioma, non-small-cell lung cancer, neuroblastoma, and renal cell carcinoma [35,105,[125][126][127][128][129][130]. Overexpression of GPC4 mRNA has been detected in metastatic colorectal cancer, where GPC1, GPC3 and GPC6, perlecan, and collagen type VIII result in being downregulated [31,35,105]. While GPC5 expression is downregulated in breast cancer, glioma, hepatocellular carcinoma, lung cancer, pancreatic cancer, prostate cancer, it results in being upregulated in rhabdomyosarcoma [35,[134][135][136][137][138].…”

Syndecan-1-Dependent Regulation of Heparanase Affects Invasiveness, Stem Cell Properties, and Therapeutic Resistance of Caco2 Colon Cancer Cells

“…For example, in colon cancer progression, there is a gradual increase in the expression of HPSE (9) and a decrease in Sdc-1 (10) expression during progression from well-differentiated to poorly differentiated colon carcinoma. Differences in the mRNA and protein expression of Sdc-1 have been noted, as Sdc-1 mRNA was strongly overexpressed in metastatic colon tumors, whereas using immunohistochemistry, metastatic tumors showed a dramatic decrease in staining, while labeling was still strong in the adjacent normal mucosa (11,12). Moreover, in metastatic tumors HPSE mRNA levels were reduced in 40% of patients, whereas overexpression was observed in 20% of patients, indicating considerable heterogeneity (11).…”