GLCE rs3865014 (Val597Ile) polymorphism is associated with breast cancer susceptibility and triple-negative breast cancer in Siberian population.

d-Glucuronyl C5-epimerase (GLCE) is one of key enzymes in heparan sulfate biosynthesis and possesses tumour-suppressor function in breast carcinogenesis. Here, we investigated a potential involvement of GLCE polymorphism(s) in breast cancer development in Siberian women population. Comprehensive analysis of SNP databases revealed GLCE rs3865014 (Val597Ile) missense polymorphism as the main significantly present in human populations. According the TaqMan-based SNP assay, allele distributions for the rs3865014 (A>G) were similar in healthy Siberian women (n=136) and cancer patients (n=129) (A0,73:G0,27) and intermediate between the European and Asian populations, while genotype distributions were different, with the increase of AG rate in breast cancer patients (OR=1.76; 95% CI=1.04-1.90; P(Y)=0.035 χ2=4.44). Heterozygous AG genotype was associated with tumour size (OR=3.67, P(Y)=0.004), ER-negative tumours (OR=3.25, P(Y)=0.0028), triple-negative tumours (OR=4.94, P(Y)=0.015) but not menopausal status, PR and HER-2 status, local or distant metastasis. Homozygous GLCE genotypes (AA/GG) were more common for ER+PR+ luminal A breast cancer (OR=0.25, P(Y)=0.031). Loss-of-heterozigosity was identified in 5 of 51 breast tumours and the loss of G allele was associated with the decreased GLCE expression. Epidemiologic data for the GLCE SNP in different racial/ethnic groups demonstrated high AG genotype rates as a risk factor not for breast cancer incidence but for poor prognosis of the disease. The obtained data suggest an involvement of GLCE rs3865014 in breast cancer development. Heterozygous AG genotype might be a risk factor for breast cancer susceptibility in Siberian women and is associated with aggressive ER-negative and triple-negative cancer subtypes.

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.