Epigenetic regulation of pluripotent genes mediates stem cell features in human hepatocellular carcinoma and cancer cell lines.

Activation of the stem cell transcriptional circuitry is an important event in cancer development. Although cancer cells demonstrate a stem cell-like gene expression signature, the epigenetic regulation of pluripotency-associated genes in cancers remains poorly understood. In this study, we characterized the epigenetic regulation of the pluripotency-associated genes NANOG, OCT4, c-MYC, KLF4, and SOX2 in a variety of cancer cell lines and in primary tumor samples, and investigated the re-activation of pluripotency regulatory circuits in cancer progression. Differential patterns of DNA methylation, histone modifications, and gene expression of pluripotent genes were demonstrated in different types of cancers, which may reflect their tissue origins. NANOG promoter hypomethylation and gene upregulation were found in metastatic human liver cancer cells and human hepatocellular carcinoma (HCC) primary tumor tissues. The upregulation of NANOG, together with p53 depletion, was significantly associated with clinical late stage of HCC. A pro-metastatic role of NANOG in colon cancer cells was also demonstrated, using a NANOG-overexpressing orthotopic tumor implantation mouse model. Demethylation of NANOG promoter was observed in CD133+(high) cancer cells. In accordance, overexpression of NANOG resulted in an increase in the population of CD133+(high) cells. In addition, we demonstrated a cross-regulation between OCT4 and NANOG in cancer cells via reprogramming of promoter methylation. Taken together, epigenetic reprogramming of NANOG can lead to the acquisition of stem cell-like properties. These results underscore the restoration of pluripotency circuits in cancer cells as a potential mechanism for cancer progression.

Aquaporin-4 autoantibodies in neuromyelitis optica spectrum disorders: comparison between tissue-based and cell-based indirect immunofluorescence assays.

BACKGROUND: Neuromyelitis optica spectrum disorders (NMOSD) are severe central nervous system inflammatory demyelinating disorders (CNS IDD) characterized by monophasic or relapsing, longitudinally extensive transverse myelitis (LETM) and/or optic neuritis (ON). A significant proportion of NMOSD patients are seropositive for aquaporin-4 (AQP4) autoantibodies. We compared the AQP4 autoantibody detection rates of tissue-based indirect immunofluorescence assay (IIFA) and cell-based IIFA. METHODS: Serum of Chinese CNS IDD patients were assayed for AQP4 autoantibodies by tissue-based IIFA using monkey cerebellum and cell-based IIFA using transfected HEK293 cells which express human AQP4 on their cell membranes. RESULTS: In total, 128 CNS IDD patients were studied. We found that 78% of NMO patients were seropositive for AQP4 autoantibodies by cell-based IIFA versus 61% by tissue-based IFA (p = 0.250), 75% of patients having relapsing myelitis (RM) with LETM were seropositive by cell-based IIFA versus 50% by tissue-based IIFA (p = 0.250), and 33% of relapsing ON patients were seropositive by cell-based IIFA versus 22% by tissue-based IIFA (p = 1.000); however the differences were not statistically significant. All patients seropositive by tissue-based IIFA were also seropositive for AQP4 autoantibodies by cell-based IIFA. Among 29 NMOSD patients seropositive for AQP4 autoantibodies by cell-based IIFA, 20 (69%) were seropositive by tissue-based IIFA. The 9 patients seropositive by cell-based IIFA while seronegative by tissue-based IIFA had NMO (3), RM with LETM (3), a single attack of LETM (1), relapsing ON (1) and a single ON attack (1). Among 23 NMO or RM patients seropositive for AQP4 autoantibodies by cell-based IIFA, comparison between those seropositive (n = 17) and seronegative (n = 6) by tissue-based IIFA revealed no differences in clinical and neuroradiological characteristics between the two groups. CONCLUSION: Cell-based IIFA is slightly more sensitive than tissue-based IIFA in detection of AQP4 autoantibodies, which are highly specific for NMOSD.

A subpopulation of CD26+ cancer stem cells with metastatic capacity in human colorectal cancer.

Recent evidence suggests that a subpopulation of cancer cells, cancer stem cells (CSCs), is responsible for tumor growth in colorectal cancer. However, the role of CSCs in colorectal cancer metastasis is unclear. Here, we identified a subpopulation of CD26(+) cells uniformly present in both the primary and metastatic tumors in colorectal cancer patients with liver metastasis. Furthermore, in patients without distant metastasis at the time of presentation, the presence of CD26(+) cells in their primary tumors predicted distant metastasis on follow-up. Isolated CD26(+) cells, but not CD26(-) cells, led to development of distant metastasis when injected into the mouse cecal wall. CD26(+) cells were also associated with enhanced invasiveness and chemoresistance. Our findings have uncovered a critical role of CSCs in metastatic progression of cancer. Furthermore, the ability to predict metastasis based on analysis of CSC subsets in the primary tumor may have important clinical implication as a selection criterion for adjuvant therapy.

Clinical phenotypes of a large Chinese multigenerational kindred with autosomal dominant familial ALS due to Ile149Thr SOD1 gene mutation.

About 10% of amyotrophic lateral sclerosis (ALS) cases are familial. We identified a five-generation Chinese family with autosomal dominant familial ALS (FALS). We performed a detailed family study, clinical and electromyographic validation, and SOD1, VEGF and CNTF mutation analyses. Forty-five living members (16 affected) were studied and DNA samples collected. Genealogical data were collected for deceased members. Based on the duration between symptom onset to ventilator dependence, they were divided into rapidly progressive (range 1-18 months, mean (SD) duration = 12.08 (+/-6.10) months, mean (SD) age of symptom onset = 39.75 (+/-9.84) years) and slowly progressive groups (>18 months; mean (SD) age of onset = 37.25 (+/-5.32) years old). We identified a heterozygous mutation of ATT to ACT of SOD1 gene at codon 149 in exon 5 resulting in substitution of isoleucine to threonine. It co-segregated with all affected members and 11 non-symptomatic members. We report a large multigenerational Chinese FALS kindred with I149T mutation in SOD1. No polymorphisms or mutations were found to date in two known modifier genes, namely, VEGF and CNTF, which were associated with heterogeneity in the phenotype within this kindred. Follow-up of the family will be helpful to explore any potential disease markers.