Browsing by Subject "suolistosyöpä"

Background and aim: Colorectal cancers (CRC) are the third most common type of cancer in men and the second most common in women worldwide. The risk for CRC is influenced by lifestyle factors, especially diet. The effect of diet on CRC risk is thought to be mediated by the liquid phase of the feces called fecal water (FW); the components in food or produced from food by the microbiome must be in soluble form to have an effect on the colon epithelial cells, especially on the proliferating cells at the bottom of the colonic crypts, and consequently on CRC risk. In this study, we examined how viability of cells from human colon cancer cell line HCA-7 was affected, when the cells were exposed to FW extracted from fecal samples from study participants eating diets with emphasis on either animal or plant protein sources. Additionally we tested, whether body mass index (BMI), pH of the FW, amount of N-nitroso compounds in feces (NOC), or intake of fiber, protein, calcium or energy correlate with viability. Materials and methods: 146 healthy voluteers (age 20–69, BMI 18,5–35) were randomly assigned to three intervention diet groups for 12 weeks. Protein content of the diets (target 17 E%) came from animal and plant sources in proportion of 70/30 % (ANIMAL-group, n=46), 50/50 % (50/50-group, n=44) and 30/70 % (PLANT-group, n=44). Food consumption was assessed using 4-day food records kept by the participants before and at the end of the intervention period. Fecal samples were collected from the same time periods. Fecal samples were diluted with water in ratio of 1:1 and homogenized, homogenate was ultracentrifuged, pH of the supernatant i.e. FW was measured and finally the FW was filtered sterile using a 0,22 μm filter. HCA-7-cells were first incubated roughly 24 h on 96-well cell culture plate in growth medium so that the cells were attached to the plate. Then three parallel FW samples in three different dilution (10 vol-%, 20 vol-% and 30 vol-%) from each study participant were added on to the plate, and the plate was further incubated exactly 24 h. After that, the amount of living cells was measured colorimetrically using WST-8-reagent. Viability (%) was determined by calculating the proportion of living cells in sample containing wells compared to the living cells in the control wells. Statistical significance of the differences of viability between the diet groups was tested by analysis of covariance (ANCOVA) using the viability at the baseline as covariate. Correlations were analyzed using Pearson’s correlation test. Results: FW samples were obtained from134 study participants. There was a statistically significant difference in viability between the groups’ means in samples with FW content of 30 vol-% (ANCOVA p=0,005). Viability (%) was smallest in the PLANT-group (co-variate adjusted mean 30,0 ± 1,9), and in the reciprocal comparison it differed from both the ANIMAL-group (37,8 ± 1,8; p = 0,011, Bonferroni correction) and the 50/50-group (37,1 ± 1,8; p = 0,021). At the end of the study, there were statistically significant correlation (p < 0,05) between viability and BMI in all of the FW contents (10 vol-%: Pearson correlation coefficient R = 0,210; 20 vol-%: R = 0,366; 30 vol-%: R = 0,319), pH of the FW in the FW contents of 20 vol-% (R = 0,204) and 30 vol-% (R = 0,249). The intake of protein (g/d) correlated in contents of 10 vol-% (R = 0,199) and 30 vol-% (R = 0,181). Also, the intake of protein in proportion to energy intake (E%) correlated in contents of 10 vol-% (R = 0,179) and 30 vol-% (R = 0,236). The intake of fiber, calcium and the amount of NOC:s in feces did not correlate with viability. Conclusions: In this study, the FW from the PLANT group reduced the viability of HCA-7 cells in vitro compared to the FW of the 50/50 ja the ANIMAL groups. This could indicate that increasing the consumption of plant-based protein sources and decreasing that of animal proteins may decrease the risk of CRC. To strengthen the current results, the exposure experiments should be replicated also using different colon cancer cell lines and a normal-like control cell line.

Ulosteen immunokemialliseen veritestiin (FIT) perustuvan kolorektaalisyövän seulontaohjelman pilottivaihe käynnistyi yhdeksässä Suomen kunnassa huhtikuussa 2019. Seulonnalla pyrittiin mahdollisimman hyvin vähentämään molempien sukupuolten taustariskiin suhteutettua syöpäkuolleisuutta. FIT-testin kynnysarvo asetettiin miehillä korkeammaksi kuin naisilla, ja molempien sukupuolten kynnysarvoja laskettiin vuoden 2020 alussa. Tutkielmassa tarkastellaan seulonnan toimivuutta ja erilaisten FIT-testin kynnysarvojen vaikutusta seulonnan tuloksiin vuosina 2019 ja 2020. Aineistossa käytettiin Suomen Syöpärekisterin tietoja seulonta-aktiivisuudesta, testituloksista ja edenneiden kasvainten osuuksista. Sukupuolittain erilaisten kynnysarvojen ja niiden muutosten vaikutusta tarkasteltiin binomiaalisella regressiolla. Suolistosyövän seulontaan osallistuttiin aktiivisesti. Miesten edenneiden kasvainten löydösosuudet olivat suuremmat kuin naisten. Kynnysarvon pienentäminen vuonna 2020 lisäsi molempien sukupuolten positiivisten testitulosten osuutta ja erityisesti naisten edenneiden kasvainten löydösosuutta. Löydettyjen kasvainten määrät suhteessa positiivisiin FIT-testeihin ja tehtyihin kolonoskopioihin pysyivät ennallaan kynnysarvoja laskettaessa. Kahden seurantavuoden aikana tutkimukseen osallistuneissa kunnissa löydettiin yhteensä 290 edennyttä adenoomaa ja 84 pahanlaatuista kasvainta. Kolorektaalisyövän seulonta toteutui ensimmäisten vuosien aikana hyvin. Kynnysarvon pienentäminen vuonna 2020 vaikutti toivotusti: edenneiden kasvainten löydösosuudet paranivat ja positiiviset ennustearvot säilyivät ennallaan.

Background Protein called ?-catenin has the key role in the Wnt signaling pathway which induces cell division and growth. The disruption of the ?-catenin degradation can lead to uncontrolled cell division and development of colon cancer due to ?-catenin´s ability to enhance the expression of the proto-oncogenes in Wnt singaling pathway. Cells control ?-catenin by degradation and phosphorylation. Phosphorylated ?-catenin at serine675 and serine552 residues increases proto-oncogene expression, and thereby promotes colon cancer formation. At present, only few research articles have addressed whether diet can affect the phosphorylation status of ?-catenin in the intestinal mucosa. Objective The objective of the master´s thesis was to develop fluorescence-based western blotting method to analyze phosphorylated ?-catenin forms from colon cancer cell and intestinal mucosa tissue samples. Optimized method was used to analyze phospho-Ser675- and phospho-Ser552-?-catenin from samples derived from two dietary studies conducted with ApcMin mice. The aim of this was to determine whether dietary components have effect on phosphorylation of ?-catenin in the intestinal mucosa tissue and whether phosphorylated ?-catenin correlated with intestinal adenoma number and size. Materials and methods Fluorescence-based western blotting method was developed to analyze all the ?-catenin phosphorylation forms that can be detected by using commercially available antibodies (Ser33/37/Thr41, Thr41/Ser45, Ser552, Ser675 and Tyr654). Phospho-?-catenin was measured from samples obtained from colon cancer cells lines and intestinal mucosa tissue of ApcMin mice (a model of colon cancer). Optimized method was used to analyze ?-catenin, phospho-Ser675- and phospho-Ser552-?-catenin levels from normal intestinal mucosa samples of ApcMin mice originated from two dietary studies. In the first study mice were fed 0,8 % plant stanol diet and in the second study mice were fed western type diet which contained high levels of fat and saturated fat and low levels of calcium and vitamin D3. The aim of the two studies was to determine whether plant stanol and western type diet have effect on tumor formation. Statistical analyses were made by using Mann-Whitney U test and Spearman correlation (PASW Statistics 18.0 software). Results By using fluorescence-based western blotting method phospho-Ser675- and phospho-Ser552-?-catenin were detected in cell and mouse samples as well as phospho-Ser33/37/Thr41-?-catenin in cell samples. The method could not be optimized for the detection of phospho-Tyr654- and phospho-Thr41/Ser45-?-catenin in cell and mouse samples and phospho-Ser33/37/Thr41-?-catenin in mouse samples. However, phospho-Thr41/Ser45-?-catenin was detected in cell samples but not in mouse samples by using the chemiluminescence-based western blotting method. The adenoma number was significantly higher in mice fed plant stanol diet than in control mice (p=0,002). Plant stanol diet resulted in significantly higher levels of ?-catenin (p=0,043) and phospho-Ser675-?-catenin (p=0,027) compared with control diet. Although, phospho-Ser552-?-catenin followed the same trend as phospho-Ser675-?-catenin, the levels of phospho-Ser552-?-catenin did not reach statistical significance between plant stanol and control group (p=0,077). Mice consumed western type diet had significantly higher number of adenomas than control mice (p=0,002). The levels of ?-catenin and phosphorylated ?-catenin (Ser552 and Ser675) were consistently higher in western type diet mice than control mice but there were no significant differences between the groups (p=0,165, p=0,198, p=0,440). Conclusions Fluorescence-based western blotting method is more reliable for analyzing ?-catenin phosphorylation forms than chemiluminescence-based western blotting method: unlike chemiluminescence-based western blotting method, fluorescence-based western blotting method can allow the detection ?-catenin and phospho-?-catenin at the same time. Based on results, diet can affect ?-catenin phosphorylation. Especially plant stanol diet increased ?-catenin fosforylation at residues serine675 as well as serine552 but less significantly in the intestinal mucosa. Phosphorylation of serine675 residue inhibits ?-catenin degradation which seems to have increased the cytosolic level of ?-catenin. Phosphorylation of serine552 residue has probably induced ?-catenin to translocate from the cytoplasm to the nucleus. Inside the nucleus ?-catenin may have promoted tumor formation by increasing the expression of proto-oncogenes.

Background Endogenous formation of possibly carcinogenic N-nitroso compounds may partly explain the association between red and processed meat and colorectal cancer. The aim of this study was to examine the effects of partial replacement of red and processed meat with legumes on the fecal total and heme-originated N-nitroso compounds (NOC) in healthy working-aged Finnish men. Methods The study was a 6-wk parallel design randomized clinical trial with two groups following either a diet supplemented with red and processed meat or a diet supplemented with legumes and red and processed meat. Total and heme-originated NOCs were analyzed from fecal homogenates using Ecomedics CLD 88. Statistical analyses were conducted using IBM SPSS Statistics 27. Independent samples t-test and Chi-Square test were used to assess the differences between the intervention groups at the baseline. Differences in total and heme-originated NOCs between the intervention groups at the endpoint were analyzed using ANCOVA (adjusted for baseline values). For correlations, Pearson correlation was used. Results 102 men completed the study. No significant differences between the groups were reported at the baseline. At the endpoint, fecal concentrations of total NOC (p < 0.0001) and heme-originated NOC (p < 0.0001) were lower in the legume and red meat group than in the red meat group. A moderate negative correlation between stool volume and NOC concentrations was observed. Conclusions The results indicate that even a partial replacement of red and processed meat with legume products can significantly reduce the total and heme-originated NOC concentrations in feces and potentially reduce the risk for the development of CRC.