Mutation of GDP-mannose-4,6-dehydratase in colorectal cancer metastasis.

Fucosylation is a crucial oligosaccharide modification in cancer. The known function of fucosylation in cancer is to mediate metastasis through selectin ligand-dependent processes. Previously, we found complete loss of fucosylation in the colon cancer cell line HCT116 due to a mutation in the GDP-fucose synthetic enzyme, GDP-mannose-4,6-dehydratase (GMDS). Loss of fucosylation led to escape of cancer cells from tumor immune surveillance followed by tumor progression and metastasis, suggesting a novel function of fucosylation in tumor progression pathway. In the present study, we investigated the frequency of GMDS mutation in a number of clinical colorectal cancer tissue samples: 81 samples of primary colorectal cancer tissue and 39 samples of metastatic lesion including liver and lymph node. Four types of deletion mutation in GMDS were identified in original cancer tissues as well as metastatic lesions. The frequency of GMDS mutation was slightly higher in metastatic lesions (12.8%, 5/39 samples) than in original cancer tissues (8.6%, 7/81 samples). No mutation of the GMDS gene was observed in normal colon tissues surrounding cancer tissues, suggesting that the mutation is somatic rather than in the germline. Immunohistochemical analysis revealed complete loss of fucosylation in three cases of cancer tissue. All three cases had GMDS mutation. In one of three cases, loss of fucosylation was observed in only metastatic lesion, but not its original colon cancer tissue. These data demonstrate involvement of GMDS mutation in the progression of colorectal cancer

Frequency of GMDS mutation in original and metastatic lesions of human colorectal cancer.

<p>Frequency of GMDS mutation in original and metastatic lesions of human colorectal cancer.</p

Clinical parameters of patients in this study.

<p>Clinical parameters of patients in this study.</p

Immunohistochemical analyses of original colorectal cancers and their metastatic lymph nodes.

<p>Thirty-three cases of original colorectal cancer tissues and four cases of their metastatic lymph nodes were stained with anti-GMDS antibody and AAL. (A) Cases 4 and 6, which depict the original colorectal cancer with GMDS mutation, but not case N, which did not have GMDS mutation, showed negative staining for both GMDS and AAL. (B, C) In case L-6, which did harbor GMDS mutation, the metastatic lymph node was not stained for GMDS (B) and AAL (C) despite positive staining for both GMDS and AAL in the original colorectal cancer tissue sample. Case L-4 without GMDS mutation showed positive staining for GMDS and AAL in both the original and metastatic legions. Bar indicates 100 µm. LN, lymph node.</p

Serum Fucosylated Haptoglobin as a Novel Diagnostic Biomarker for Predicting Hepatocyte Ballooning and Nonalcoholic Steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) is a growing medical problem around the world. NAFLD patients with nonalcoholic steatohepatitis (NASH) can develop cirrhosis and hepatocellular carcinoma. The ability to distinguish NASH from simple steatosis would be of great clinical significance. Ballooning hepatocytes are characteristic of typical pathological NASH; here, the polarized secretion of proteins is disrupted due to destruction of the cytoskeleton. We previously reported that fucosylated glycoproteins are secreted into bile, but not into sera in normal liver. Therefore, we hypothesized that the fucosylation-based sorting machinery would be disrupted in ballooning hepatocytes, and serum fucosylated glycoproteins would increase in NASH patients. To confirm our hypothesis, we evaluated serum fucosylated haptoglobin (Fuc-Hpt) levels in biopsy-proven NAFLD patients (n = 126) using a lectin-antibody ELISA kit. Fuc-Hpt levels were significantly increased in NASH patients compared with non-NASH (NAFLD patients without NASH) patients. Interestingly, Fuc-Hpt levels showed a significant stepwise increase with increasing hepatocyte ballooning scores. Multiple logistic regression analysis showed that Fuc-Hpt levels were independent and significant determinants of the presence of ballooning hepatocytes. Moreover, Fuc-Hpt levels were useful in monitoring liver fibrosis staging. Next, to investigate the significance of serum Fuc-Hpt in a larger population, we measured Fuc-Hpt levels in ultrasound-diagnosed NAFLD subjects (n = 870) who received a medical health checkup. To evaluate NAFLD disease severity, we used the FIB-4 index (based on age, serum AST and ALT levels, and platelet counts). Fuc-Hpt levels increased stepwise with increasing FIB-4 index.Measurement of serum Fuc-Hpt levels can distinguish NASH from non-NASH patients, and predict the presence of ballooning hepatocytes in NAFLD patients with sufficient accuracy. These results support the potential usefulness of measuring Fuc-Hpt levels in clinical practice

Correlation between serum Fuc-Hpt levels and liver fibrosis stage in biopsy-proven NAFLD patients.

<p>(A) Serum Fuc-Hpt levels in each stage of liver fibrosis in NAFLD patients. (B) ROC curves for Fuc-Hpt and the M30 antigen for discrimination of advanced liver fibrosis in biopsy-proven NAFLD patients.</p

Clinical and biochemical characteristics of NAFLD subjects in the health check-up study.

<p>Data are presented as the mean ± SD.</p