secoisolariciresinol-diglucoside and Colonic-Neoplasms

Apoptotic effects of secoisolariciresinol diglucoside (SDG) in 2D and 3D cultures of SW480 cells were investigated. 40-200 μM SDG was used and IC50 values were determined for three different time intervals as 24, 48, or 72 hr for further experiments. BrdU, TUNEL, AIF, and caspase-3 stainings were used. SDG inhibited cell proliferation almost half and half for all time intervals in 2D and 3D cultures and also, induced apoptosis. Apoptotic cell percentages in the control group for 24, 48, and 72 hr were 27.00%, 29.00%, and 28.00%, respectively, while in the SDG treatment group were 59.00%, 61.00%, and 62.00%, respectively. In the spheroid cell culture, apoptotic cell percentages in the control group for 24, 48, and 72 hr were 6.90%, 7.20%, and 7.10%, respectively, while in the SDG treatment group were 19.50%, 19.50%, and 20.70%, respectively. Caspase-3 and AIF antibodies were used to indicate caspase-dependent and -independent apoptotic pathways. Significant increases were seen in both AIF and caspase-3 stainings when compared to the control group but caspase-3 staining results were significantly greater when compared to the AIF staining at all time intervals (p < .05). To prove this, CASP3 gene expression was evaluated by RT-qPCR. Unlike staining results, there was no statistically significant change at 24 hr in 2D and 3D cultures. But, significant upregulation at 48 (2.32-fold in 2D and 2.46-fold in 3D) and 72 hr (5.04-fold in 2D and 6.45-fold in 3D) were seen. PRACTICAL APPLICATIONS: Colon cancer is one of the most prevalent cancer in the developed countries and its etiology is complex. Although the underlying mechanisms are mostly unknown, the link between diet and colon cancer is known and dietary habits can promote cancer or protect against it. In recent years, flaxseed is accepted as a significant functional food ingredient and feeding with it could help in to prevent cancer. Secoisolariciresinol diglucoside is a flaxseed lignan and is metabolized to mammalian lignans by the gut. In the present study, SDG was evaluated for its apoptotic effects in colon carcinoma cell line via monolayer and spheroid cultures using immunohistochemical and gene expression techniques. Findings of this study suggest that SDG may protect against cancers and in particularly against colon cancer and further investigations has to be carried out for detailed underlying mechanisms.

Topics: Animals; Apoptosis; Butylene Glycols; Carcinoma; Caspase 3; Colonic Neoplasms; Glucosides; Humans

There is increased risk of colon cancer in both men and women having diabetes. The objective of the study was to evaluate the role of Secoisolariciresinol diglucoside rich extract(SRE) of L.usissatisimum(flaxseed) in colon cancer associated with type 2 diabetes mellitus.. Diabetes was induced by administering high fat diet with low dose streptozotocin model. After 6 weeks, diabetes was confirmed and 1,2 dimethylhydrazine(25mg/kg, sc) weekly administration was from 6th to 18th weeks. Rats were treated with the SRE(500mg/kg) orally from 6th to 24th week. After 24 weeks, various biochemical and enzymatic parameters were estimated. Animals were sacrificed and colon tissue was separated and subjected to analysis of histopathological, PCNA studies and mRNA expression of CDK4.. Disease control rats depicted hyperglycaemia, hyperinsulinaemia, elevated pro-inflammatory cytokines and cancer biomarker levels, and marked presence of proliferating cells. Treatment with SRE controlled hyperglycaemia, hyperinsulinaemia, reduced pro-inflammatory cytokines and cancer biomarker levels, and decreased no. of proliferating cells. We found that disease control rats depicted over expression of CDK4 mRNA levels which were reduced by SRE treatment.. SRE of L. usitatissimum exhibited chemopreventive effect in colon cancer associated with type 2 diabetes mellitus which might be mediated through inhibition of CDK4.

Topics: Animals; Biomarkers, Tumor; Butylene Glycols; Cell Proliferation; Colonic Neoplasms; Cyclin-Dependent Kinase 4; Cytokines; Diabetes Mellitus, Type 2; Female; Flax; Gene Expression Regulation, Neoplastic; Glucose Tolerance Test; Glucosides; Hyperglycemia; Inflammation Mediators; Male; Phytochemicals; Plant Extracts; Proliferating Cell Nuclear Antigen; Rats, Sprague-Dawley; RNA, Messenger

Our previous study demonstrated that lignan metabolites enterolactone and enterodiol inhibited colonic cancer cell growth by inducing cell cycle arrest and apoptosis. However, the dietary lignans are naturally present as glycoside precursors, such as secoisolariciresinol diglucoside (SDG), which have not been evaluated yet. This study tested the hypothesis that dietary SDG might have a different effect than its metabolites in human colonic SW480 cancer cells. Treatment with SDG at 0 to 40 μmol/L for up to 48 hours resulted in a dose- and time-dependent decrease in cell numbers, which was comparable to enterolactone. The inhibition of cell growth by SDG did not appear to be mediated by cytotoxicity, but by a cytostatic mechanism associated with an increase of cyclin A expression. Furthermore, high-performance liquid chromatography analysis indicated that SDG in the media was much more stable than enterolactone (95% of SDG survival vs 57% of enterolactone after 48-hour treatment). When the cells were treated with either enterolactone or SDG at 40 μmol/L for 48 hours, the intracellular levels of enterolactone, as measured by high-performance liquid chromatography-mass spectrometry/electron spray ionization, were about 8.3 × 10(-8) nmol per cell; but intracellular SDG or potential metabolites were undetectable. Taken together, SDG demonstrated similar effects on cell growth, cytotoxicity, and cell cycle arrest when compared with its metabolite enterolactone. However, the reliable stability and undetectable intracellular SDG in treated cells may suggest that metabolism of SDG, if exposed directly to the colonic cells, could be different from the known degradation by microorganisms in human gut.

Topics: 4-Butyrolactone; Adenocarcinoma; Anticarcinogenic Agents; Butylene Glycols; Cell Cycle; Cell Line, Tumor; Chromatography, High Pressure Liquid; Colonic Neoplasms; Cyclin A; Cytostatic Agents; Dietary Carbohydrates; Dose-Response Relationship, Drug; Glucosides; Glycosides; Humans; Lignans; Mass Spectrometry

Flaxseed, the richest source of mammalian lignan precursors, such as secoisolariciresinol diglycoside (SD), has been shown over the short term to decrease some early markers of colon cancer risk. This study determined whether over the long term flaxseed still exerts a colon cancer protective effect, whether its effect may, in part, be due to its high content of SD and whether any change in beta-glucuronidase activity plays a role in the protective effect. Six groups of male Sprague-Dawley rats were fed for 100 days either a basal high fat (20%) diet (BD), BD supplemented with 2.5 or 5% flaxseed or 2.5 or 5% defatted flaxseed (equivalent to the respective flaxseed diets) or BD with a daily gavage of 1.5 mg SD. All rats were injected with a single dose of azoxymethane (15 mg/kg body wt) 1 week prior to commencing the dietary treatments. Urinary lignan excretion, which is an indicator of mammalian lignan production, was significantly increased in the flaxseed and defatted flaxseed groups. The total activity of cecal beta-glucuronidase was significantly increased in a dose-dependent manner by the flaxseed and defatted flaxseed diet groups. Compared with the control the number of aberrant crypts per focus was significantly reduced in the distal colon of the treated rats. Four microadenomas and two polyps were observed in the control group, but not in the treated groups. The total activity of beta-glucuronidase was positively correlated with total urinary lignan excretion and negatively with the total number of aberrant crypts and the total number of aberrant crypt foci in the distal colon. There were no significant differences between the flaxseed and the corresponding defatted flaxseed groups. It is concluded that flaxseed has a colon cancer protective effect, that it is due, in part, to SD and that the protective effect of flaxseed is associated with increased beta-glucuronidase activity.

Topics: Animals; Anticarcinogenic Agents; Body Weight; Butylene Glycols; Cecum; Colonic Neoplasms; Eating; Fatty Acids; Glucosides; Glucuronidase; Hydrogen-Ion Concentration; Lignans; Male; Organ Size; Plant Extracts; Precancerous Conditions; Rats; Rats, Sprague-Dawley; Seeds