Up-regulation of 12(S)-lipoxygenase induces a migratory phenotype in colorectal cancer cells.

12(S)-Lipoxygenase (LOX) and its product 12(S)-hydroxyeicosatetraenic (HETE) acid have been implicated in angiogenesis and tumour invasion in several tumour types while their role in colorectal cancer progression has not yet been studied. We have analysed 12(S)-LOX expression in colorectal tumours and found gene expression up-regulated in colorectal cancer specimens for which the pathology report described involvement of inflammation. Using cell line models exposed to 12(S)-HETE or over-expressing 12(S)-LOX malignant cell growth as well as tumour cell migration was found to be stimulated. Specifically, Caco2 and SW480 cells over-expressing 12(S)-LOX formed fewer colonies from sparse cultures, but migrated better in filter-migration assays. SW480 LOX cells also had higher anchorage-independent growth capacity and a higher tendency to metastasise in vivo. Knock-down or inhibition of 12(S)-LOX inhibited cell migration and anchorage-independent growth in both 12(S)-LOX transfectants and SW620 cells that express high endogenous levels of 12(S)-LOX. On the cell surface E-cadherin and integrin-ß1 expression were down-regulated in a 12(S)-LOX-dependent manner disturbing cell-cell interactions. The results demonstrate that 12(S)-LOX expression in inflammatory areas of colorectal tumours has the capacity to induce an invasive phenotype in colorectal cancer cells and could be targeted for therapy.

Fibroblast growth factor receptor 3-IIIc mediates colorectal cancer growth and migration.

BACKGROUND: Deregulation of fibroblast growth factor receptor 3 (FGFR3) is involved in several malignancies. Its role in colorectal cancer has not been assessed before. METHODS: Expression of FGFR3 in human colorectal tumour specimens was analysed using splice variant-specific real-time reverse transcriptase PCR assays. To analyse the impact of FGFR3-IIIc expression on tumour cell biology, colon cancer cell models overexpressing wild-type (WT-3b and WT3c) or dominant-negative FGFR3 variants (KD3c and KD3b) were generated by either plasmid transfection or adenoviral transduction. RESULTS: Although FGFR3 mRNA expression is downregulated in colorectal cancer, alterations mainly affected the FGFR3-IIIb splice variant, resulting in an increased IIIc/IIIb ratio predominantly in a subgroup of advanced tumours. Overexpression of WT3c increased proliferation, survival and colony formation in all colon cancer cell models tested, whereas WT3b had little activity. In addition, it conferred sensitivity to autocrine FGF18-mediated growth and migration signals in SW480 cells with low endogenous FGFR3-IIIc expression. Disruption of FGFR3-IIIc-dependent signalling by dominant-negative FGFR3-IIIc or small interfering RNA-mediated FGFR3-IIIc knockdown resulted in inhibition of cell growth and induction of apoptosis, which could not be observed when FGFR3-IIIb was blocked. In addition, KD3c expression blocked colony formation and migration and distinctly attenuated tumour growth in SCID mouse xenograft models. CONCLUSION: Our data show that FGFR3-IIIc exerts oncogenic functions by mediating FGF18 effects in colorectal cancer and may constitute a promising new target for therapeutic interventions.

Influence of a probiotic yoghurt on the status of vitamins B(1), B(2) and B(6) in the healthy adult human.

BACKGROUND/AIMS: The main reason for this study was to determine whether yoghurt bacteria, being rich in some water-soluble vitamins, release them or utilize vitamins from their surroundings. Our study was trying to determine for the first time, if the viable bacteria of probiotic yoghurt are able to influence the parameters of the B-vitamin (B(1), B(2), B(6)) status of the healthy adult human. METHODS: The test yoghurt was commercially available probiotic yoghurt prepared with Streptococcus thermophilus and Lactobacillus acidophilus, enriched with Lactobacillus casei GG. Different chemical forms of all investigated B-vitamins were determined by HPLC methods. In order to determine the influence of the yoghurt flora, each of 12 subjects consumed four yoghurt portions 125 g each ( = 500 g) a day, containing thermally inactivated cultures during the first 2-week period and yoghurt without heat treatment during the second 2-week period. RESULTS: The heat treatment of the probiotic yoghurt caused negligible changes in vitamin contents. The plasma levels of thiamin decreased significantly (p < 0.01) after the first 2-week period and kept on decreasing during the second 2-week period. A similar trend was found in the urinary excretion. The plasma levels of the B(2)-vitamers were different. The flavin adenine dinucleotide concentrations increased significantly (p < 0.01) after the consumption of heat-treated yoghurt and decreased significantly (p < 0.05) after the following 2 weeks, in which the subjects received the untreated yoghurt. In contrast, the flavin mononucleotide plasma levels decreased during the first 2-week period and increased during the second part of the study, but the change was not statistically significant. The free riboflavin concentrations in plasma and urine showed a continuous but not significant increase. The concentrations of pyridoxal-5-phosphate in plasma increased after the consumption of yoghurt with the inactivated bacteria and decreased in the second part of the study. However, the differences were not significant. The excretion of thiamin, B(2)- and B(6)-vitamers in the faeces did not significantly change throughout the study period (p>0.05). CONCLUSIONS: Our observations show that the bacterial flora of the examined yoghurt does not influence the vitamin B(1), B(2) and B(6) status of man. It seems likely that even lactobacilli of the 'probiotic' type which are vitamin B consumers can decrease the bioavailability of these vitamins for man. Obviously a thermal death of the cells did not induce a release of physiologically active vitamins.