Proteoglycans as potential microenvironmental biomarkers for colon cancer

Tissue-specificity of heparan sulfate biosynthetic machinery in cancer

Heparan sulfate (HS) proteoglycans are key components of cell microenvironment and fine structure of their polysaccharide HS chains plays an important role in cell-cell interactions, adhesion, migration and signaling. It is formed on non-template basis, so, structure and functional activity of HS biosynthetic machinery is crucial for correct HS biosynthesis and post-synthetic modification. To reveal cancer-related changes in transcriptional pattern of HS biosynthetic system, the expression of HS metabolism-involved genes (EXT1/2, NDST1/2, GLCE, 3OST1/HS3ST1, SULF1/2, HPSE) in human normal (fibroblasts, PNT2) and cancer (MCF7, LNCaP, PC3, DU145, H157, H647, A549, U2020, U87, HT116, KRC/Y) cell lines and breast, prostate, colon tumors was studied. Real-time RT-PCR and Western-blot analyses revealed specific transcriptional patterns and expression levels of HS biosynthetic system both in different cell lines in vitro and cancers in vivo. Balance between transcriptional activities of elongation- and post-synthetic modification- involved genes was suggested as most informative parameter for HS biosynthetic machinery characterization. Normal human fibroblasts showed elongation-oriented HS biosynthesis, while PNT2 prostate epithelial cells had modification-oriented one. However, cancer epithelial cells demonstrated common tendency to acquire fibroblast-like elongation-oriented mode of HS biosynthetic system. Surprisingly, aggressive metastatic cancer cells (U2020, DU145, KRC/Y) retained modification-oriented HS biosynthesis similar to normal PNT2 cells, possibly enabling the cells to keep like-to-normal cell surface glycosylation pattern to escape antimetastatic control. The obtained results show the cell type-specific changes of HS-biosynthetic machinery in cancer cells in vitro and tissue-specific changes in different cancers in vivo, supporting a close involvement of HS biosynthetic system in carcinogenesis.

Syndecan-1 in Cancer: Implications for Cell Signaling, Differentiation, and Prognostication

Syndecan-1, a cell surface heparan sulfate proteoglycan, is critically involved in the differentiation and prognosis of various tumors. In this review, we highlight the synthesis, cellular interactions, and the signalling pathways regulated by syndecan-1. The basal syndecan-1 level is also crucial for understanding the sequential changes involving malignant transformation, tumor progression, and advanced or disseminated cancer stages. Moreover, we focus on the cellular localization of this proteoglycan as cell membrane anchored and/or shed, soluble syndecan-1 with stromal or nuclear accumulation and how this may carry different, highly tissue specific prognostic information for individual tumor types.

Decorin in Human Colon Cancer: Localization In Vivo and Effect on Cancer Cell Behavior In Vitro

Decorin is generally recognized as a tumor suppressing molecule. Nevertheless, although decorin has been shown to be differentially expressed in malignant tissues, it has often remained unclear whether, in addition to non-malignant stromal cells, cancer cells also express it. Here, we first used two publicly available databases to analyze the current information about decorin expression and immunoreactivity in normal and malignant human colorectal tissue samples. The analyses demonstrated that decorin expression and immunoreactivity may vary in cancer cells of human colorectal tissues. Therefore, we next examined decorin expression in normal, premalignant and malignant human colorectal tissues in more detail using both in situ hybridization and immunohistochemistry for decorin. Our results invariably demonstrate that malignant cells within human colorectal cancer tissues are devoid of both decorin mRNA and immunoreactivity. Identical results were obtained for cells of neuroendocrine tumors of human colon. Using RT-qPCR, we showed that human colon cancer cell lines are also decorin negative, in accordance with the above in vivo results. Finally, we demonstrate that decorin transduction of human colon cancer cell lines causes a significant reduction in their colony forming capability. Thus, strategies to develop decorin-based adjuvant therapies for human colorectal malignancies are highly rational.