Background: Proanthocyanidins (PACs) from black soybean seed coat have antioxidant and anti-tumorigenic properties. We investigated the anti-tumor properties and mechanisms of action of PACs on colorectal cancer (CRC). Methods: We fed the APCmin/+mice, which are highly susceptible to spontaneous intestinal adenoma formation, diets supplemented with or without PACs for 7 weeks and assessed adverse effects, the number and size of intestinal polyps, and the expression of pro- and anti-proliferative proteins in the intestine. The mouse gut microbiome composition was analyzed, and the concentrations of gut short-chain fatty acids (SCFAs) were quantified. We also compared CRC incidence in Tamba in Japan, where black soybean is consumed frequently, with that in the rest of Japan. Results: The number and size of intestinal polyps notably decreased in the PAC-fed mice. Compared with control mice, the PAC-fed mice showed lower expression of proliferation markers proliferating cell nuclear antigen and β catenin and a higher expression of the anti-inflammatory protein oligomeric mucus gel-forming. PAC supplementation increased the prevalence and concentrations of beneficial gut microbes and SCFAs, respectively. Conclusions: Diet supplemented with black soybean-derived PACs could prevent CRC development in mice through gut microbiome remodeling. Regions consuming black soybeans have low CRC incidence. Notably, the incidence of CRC, breast cancer, and liver cancer was significantly lower in Tamba than in the rest of Hyogo Prefecture or Japan. Future studies should delineate the mechanisms underlying the CRC-protective effects of PACs. Nevertheless, our results demonstrate the potential of including PACs in dietary recommendations for cancer prevention.
背景：黑豆种皮中的原花青素具有抗氧化和抗肿瘤特性。本研究旨在探讨原花青素对结直肠癌的抗肿瘤作用及其机制。方法：我们给易自发形成肠道腺瘤的APCmin/+小鼠分别饲喂添加或不添加原花青素的饲料，持续7周，评估其不良反应、肠道息肉的数量和大小，以及肠道内促增殖和抗增殖蛋白的表达。分析小鼠肠道微生物组成，并量化肠道短链脂肪酸浓度。同时，我们比较了日本丹波地区（黑豆消费频繁）与日本其他地区的结直肠癌发病率。结果：饲喂原花青素的小鼠肠道息肉的数量和大小显著减少。与对照组相比，原花青素组小鼠的增殖标志物增殖细胞核抗原和β-连环蛋白表达降低，抗炎蛋白寡聚黏液凝胶形成蛋白表达升高。补充原花青素分别增加了有益肠道微生物的丰度和短链脂肪酸的浓度。结论：添加黑豆来源原花青素的饮食可通过重塑肠道微生物群预防小鼠结直肠癌的发生。黑豆消费地区的结直肠癌发病率较低。值得注意的是，丹波地区的结直肠癌、乳腺癌和肝癌发病率显著低于兵库县其他地区或日本全国。未来研究应阐明原花青素保护作用的具体机制。尽管如此，我们的结果证明了将原花青素纳入饮食建议以预防癌症的潜力。
肿瘤(癌症)患者之家