| Summary: | 碩士 === 國立臺灣大學 === 醫學檢驗暨生物技術學研究所 === 106 === In previous loss of heterozygosity (LOH) study, we explore N-deacetylase/N-sulfotransferase 4 (NDST4) as a novel tumor suppressor gene (TSG) at chromosome 4q25-q28.2 in colorectal cancer (CRC). NDST4 is one of the pivotal enzymes responsible for heparan sulfate biosynthesis on a core protein to form heparan sulfate proteoglycans (HSPGs), which play important roles in development、 inflammation and tumorigenesis. We have proposed that loss of NDST4 function might impair the biosynthesis of specific HSPGs leading to tumor-promoting inflammation and tumor progression. In the study, we further aimed to investigate NDST4-mediated modulation of macrophage polarization and angiogenesis in CRC. First, macrophage differentiation model were established with THP-1 and U937 cells. Macrophage subtype were determined by morphological change and surface marker expression measured by qRT-PCR and flow cytometry. CRC cells with inducible NDST4 expression, including a single stable clone (HCT116/NDST4-C5) and a mixed line (HCT116/NDST4-Mix), were established in previous study. CRC cells expressing NDST4 and the conditioned media harvested could promte M0 cells differentiation into M1-polarized macrophages. Meanwhile, previously established xenogrft tumor tissue sections were used to perform immunohistochemistry staining of CD68 (M0). The results revealed larger numbers of tumor-associated macrophage in NDST4 expressing xenograft tumor. In the second part, NDST4 expression in CRC cells decrease the gene expression and protein secretion of urokinase-type plasminogen activator (uPA). In addition, uPA upregulation was observed in 51 primary tumor collected when compared to their matched normal mucosa. By using 4 public CRC datasets, the uPA expression is signigicantly higher in the tumors of high risk group than that in the tumors of low risk group. In contrast, the NDST4 expression is significantly lower in the tumors of high risk group.
The conditioned medium from CRC cells expressing NDST4 exhibited a decreased level of Serpin E1、MIF、IL-8、CXCL12 and CXCL1 by cytokine array analysis. Taken together, NDST4 expression in CRC cells might decrease the synthesis and/or secretion of the mediators, and these modulate macrophage differentiation and tumor angiogenesis in tumor microenvironment.
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