Xenobiotic metabolism, cancer chemoprevention and cancer biomarkers

圣约翰草（SJW）通过抑制炎症信号减轻小鼠结肠直肠癌的发生：SJW是一种广泛使用的非处方膳食补充剂。金丝桃提取物的成分，如金丝桃素和金丝桃素被发现能减弱神经递质受体，这是其作为非处方抗抑郁药使用的主要卖点。hyperperin还会引发肺癌和结肠癌细胞系的凋亡，而食用SJW提取物与降低患结肠直肠癌的风险有关。然而，这种保护的潜在机制尚未确定。考虑到SJW成分和/或提取物被证明会增加新陈代谢并损害包括抗癌药物在内的药物的功效，这一点尤为重要。采用aom诱导的结直肠癌模型，研究SJW提取物对结直肠癌的预防作用。以小鼠为实验对象，研究了日粮中添加SJW提取物对aom诱导的结直肠癌的影响。小鼠在AOM治疗前分别饲喂AIN-93G（对照）饲粮或SJW提取物补充饲粮（SJW饲粮）。研究发现，SJW日粮显著提高了aom处理小鼠的总体存活率。SJW饮食预处理显著降低了与aom诱导的结直肠肿瘤发生相关的体重减轻以及血清白蛋白和胆固醇水平。SJW饮食喂养小鼠显示肿瘤多样性显著降低，大肿瘤发生率降低，肿瘤总体积呈剂量依赖性降低趋势。一项短期研究检测了SJW在直肠出血前的作用，也显示SJW饮食喂养的小鼠结肠息肉减少。NF-kB和细胞外信号调节激酶（erk1 /2）通路被SJW减弱。在短期和长期治疗方案下，SJW提取物导致SJW饮食喂养小鼠结肠上皮中这些通路的早期和持续衰减。综上所述，本研究证明了SJW提取物通过抑制促炎过程对结直肠癌的化学预防潜力。香料肉豆蔻对结肠癌的调节作用：肉豆蔻是肉豆蔻属植物肉豆蔻的种子，对胃肠道疾病有治疗作用，在中国被广泛用于治疗胃病。已知肉豆蔻对变形菌门具有抗菌活性，特别是对幽门螺杆菌和大肠杆菌。肉豆蔻对硫酸葡聚糖钠诱导的小鼠结肠炎有保护作用。这些观察结果表明，肉豆蔻可能通过调节炎症、氧化剂和肠道微生物群来预防结肠癌。基于uplc - esi - qtofms的代谢组学研究揭示了四种尿毒症毒素（甲酚硫酸酯、甲酚葡萄糖醛酸酯、硫酸吲哚酚和硫酸苯酯）在携带腺瘤性大肠息肉病（APC）基因突变诱导的结肠癌小鼠血清中的积累。这些尿毒症毒素可能来自肠道微生物群，与促炎细胞因子IL-6的表达增加和脂质代谢紊乱有关。在Apcmin/+小鼠中，肉豆蔻具有抗菌活性，可以降低尿毒症毒素的水平，减少肠道肿瘤的发生。肉豆粕处理的Apcmin/+小鼠IL-6水平降低，脂质代谢失调正常化，表明尿毒症毒素是肿瘤发生过程中代谢紊乱的部分原因。这些研究表明肠道微生物代谢、炎症和代谢紊乱之间存在潜在的生化联系，并提示通过饮食干预或药物调节肠道微生物群和脂质代谢可能是有效的结肠癌化学预防策略。n -甲基烟酰胺和烟酰胺n -甲基转移酶与microrna -1291改变的胰腺癌细胞代谢组和抑制肿瘤发生有关：细胞代谢组包含丰富的信息，可以预测细胞在细胞增殖和转移的不同阶段对表观遗传或遗传变化的反应。一项基于无偏超高效液相色谱-质谱的代谢组学研究显示，在异种移植肿瘤小鼠模型中，具有功能获得性非编码microRNA-1291 （miR-1291）的人胰腺癌PANC-1细胞的代谢组学发生了显著改变，导致其迁移和侵袭能力降低，并抑制了肿瘤的发生。在表达mir -1291的PANC-1中，参与烟酰胺代谢的n -甲基烟酰胺和参与脂肪酸代谢的左旋肉碱、异丁基左旋肉碱和异戊基左旋肉碱等多种代谢物均升高。值得注意的是，n -甲基烟酰胺在表达mir -1291的PANC-1细胞中最大程度地升高，这与烟酰胺n -甲基转移酶（NNMT） mRNA水平的急剧增加有关。此外，在异种移植小鼠模型中，NNMT mRNA的表达与胰腺肿瘤大小呈负相关。这些结果表明，mir -1291改变的PANC-1细胞功能与n -甲基烟酰胺水平和NNMT表达的增加有关，反过来，NNMT可能指示胰腺癌发生的程度。吡喹酮对映体的代谢谱分析：吡喹酮（PZQ）是一种外消旋混合物，是最容易获得的治疗血吸虫病的药物。本研究采用超高效液相色谱-电喷雾电离四极杆飞行时间质谱（UPLC-ESI-QTOFMS）为基础的代谢组学方法，分析了PZQ的代谢途径和对端选择性代谢差异。给药24小时后，在小鼠的尿液和粪便样本中发现了许多I期代谢物和4种新的II期代谢物，表明主要代谢反应包括氧化、脱氢和葡萄糖醛酸化。在(R)-PZQ和(S)-PZQ之间观察到所有这些代谢物的形成差异。在体外I期培养体系中，CYP3A、CYP2C9和CYP2C19主要参与PZQ的代谢，CYP3A、CYP2C9和CYP2C19对PZQ对映体表现出不同的催化活性。CYP2C9和CYP3A4对三种单氧化代谢物的催化生成Km和Vmax存在明显差异，进一步支持了PZQ对映体的代谢差异。分子对接表明，手性导致底物位置和构象的差异，这可能是代谢差异的原因。总之，硅、体外和体内方法揭示了吡喹酮的对映选择性代谢谱。

St. John's wort (SJW) attenuates colorectal carcinogenesis in mice through suppression of inflammatory signaling: SJW is a widely used dietary supplement available over the counter. Components of SJW extract, such as, hypericin and hyperforin were found to attenuate neurotransmitters receptors which the main marketing point for the its use as an over-the-counter antidepressant. Hyperforin also triggers apoptosis of lung and the colon cancer cell lines, and consumption of SJW extract was associated with reduced risk of developing colorectal cancer. However, the underlying mechanism of this protection has not been determined. This is particularly important given the fact that SJW constituents and/or extracts were shown to increase the metabolism and compromise the efficacy of drugs including anti-cancer agents. The prophylactic effect of SJW extract on colorectal carcinogenesis was examined using the AOM-induced colorectal carcinogenesis mode. The impact of dietary supplementation of SJW extract on AOM-induced colorectal carcinogenesis was evaluated in mice. Mice were fed with either AIN-93G (control) diet or SJW extract-supplemented diet (SJW diet) prior to AOM treatment. SJW diet was found to significantly improve the overall survival of AOM-treated mice. Pre-treatment with the SJW diet significantly reduced body weight loss as well as decrease of serum albumin and cholesterol levels associated with AOM-induced colorectal tumorigenesis. SJW diet-fed mice showed a significant decrease in tumor multiplicity along with a decrease in incidence of large tumors and a trend towards decreased total tumor volume in a dose-dependent manner. A short-term study, which examined the effect of SJW prior to rectal bleeding, also showed a decrease in colorectal polyps in SJW diet-fed mice. NF-kB and extracellular signal-regulated kinase (ERK 1/2) pathways were attenuated by SJW administration. SJW extract resulted in early and continuous attenuation of these pathways in the colon epithelium of SJW diet-fed mice under both short term and long term treatment regimens. In conclusion, this study demonstrated the chemopreventive potential of SJW extract against colorectal cancer through attenuation of pro-inflammatory processes. Modulation of Colon Cancer by the Spice Nutmeg: Nutmeg, the seed of the fruit of Myristica fragrans, shows therapeutic efficacy in gastrointestinal disorders, and is a widely used agent for the treatment of stomach ailments in China. Nutmeg is known to exhibit antimicrobial activity against the phylum Proteobacteria, especially in Helicobacter pylori and Escherichia coli. Nutmeg can protect against dextran sulfate sodium-induced colitis in mice. These observations suggested that nutmeg might prevent colon cancer via the modulation of inflammation, oxidants and gut microbiota. By UPLC-ESI-QTOFMS-based metabolomics, this study revealed the accumulation of four uremic toxins (cresol sulfate, cresol glucuronide, indoxyl sulfate, and phenyl sulfate) in the serum of mice harboring adenomatous polyposis coli (APC) gene mutation-induced colon cancer. These uremic toxins, likely generated from the gut microbiota, were associated with increased expression of the proinflammatory cytokine IL-6 and a disorder of lipid metabolism. Nutmeg, that exhibits antimicrobial activity, attenuated the levels of uremic toxins and decreased intestinal tumorigenesis in Apcmin/+ mice. Nutmeg-treated Apcmin/+ mice had decreased IL-6 levels and normalized dysregulated lipid metabolism, suggesting that uremic toxins are responsible in part for the metabolic disorders that occur during tumorigenesis. These studies demonstrate a potential biochemical link between gut microbial metabolism, inflammation and metabolic disorders, and suggest that modulation of the gut microbiota and lipid metabolism using dietary intervention or drugs may be effective colon cancer chemoprevention strategies. N-methylnicotinamide and nicotinamide N-methyltransferase are associated with microRNA-1291-altered pancreatic carcinoma cell metabolome and suppressed tumorigenesis: The cell metabolome comprises abundant information that may be predictive of cell functions in response to epigenetic or genetic changes at different stages of cell proliferation and metastasis. An unbiased ultra-performance liquid chromatography-mass spectrometry-based metabolomics study revealed a significantly altered metabolome for human pancreatic carcinoma PANC-1 cells with gain-of-function non-coding microRNA-1291 (miR-1291), which led to a lower migration and invasion capacity as well as suppressed tumorigenesis in a xenograft tumor mouse model. A number of metabolites, including N-methylnicotinamide, involved in nicotinamide metabolism, and l-carnitine, isobutyryl-carnitine and isovaleryl-carnitine, involved in fatty acid metabolism, were elevated in miR-1291-expressing PANC-1. Notably, N-methylnicotinamide was elevated to the greatest extent, and this was associated with a sharp increase in nicotinamide N-methyltransferase (NNMT) mRNA level in miR-1291-expressing PANC-1 cells. In addition, expression of NNMT mRNA was inversely correlated with pancreatic tumor size in the xenograft mouse model. These results indicate that miR-1291-altered PANC-1 cell function is associated with the increase in N-methylnicotinamide level and NNMT expression, and in turn NNMT may be indicative of the extent of pancreatic carcinogenesis. Metabolic profiling of praziquantel enantiomers: Praziquantel (PZQ), prescribed as a racemic mixture, is the most readily available drug to treat schistosomiasis. In the present study, ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) based metabolomics was employed to decipher the metabolic pathways and enantioselective metabolic differences of PZQ. Many phase I and four new phase II metabolites were found in urine and feces samples of mice 24h after dosing, indicating that the major metabolic reactions encompassed oxidation, dehydrogenation, and glucuronidation. Differences in the formation of all these metabolites were observed between (R)-PZQ and (S)-PZQ. In an in vitro phase I incubation system, the major involvement of CYP3A, CYP2C9, and CYP2C19 in the metabolism of PZQ, and CYP3A, CYP2C9, and CYP2C19 exhibited different catalytic activity toward the PZQ enantiomers. Apparent Km and Vmax differences were observed in the catalytic formation of three mono-oxidized metabolites by CYP2C9 and CYP3A4 further supporting the metabolic differences for PZQ enantiomers. Molecular docking showed that chirality resulted in differences in substrate location and conformation, which likely accounts for the metabolic differences. In conclusion, in silico, in vitro, and in vivo methods revealed the enantioselective metabolic profile of praziquantel.