Lorcaserin是5-羟色胺2C(5-羟色胺)受体激动剂和非遗传毒性大鼠致癌物,在为期两年的生物测定中,在雄性和雌性大鼠中诱导了乳腺肿瘤。雌性SpragueDawley大鼠每天用0、30或100mg/kg的氯卡色林进行灌胃治疗,复制生物测定给药,但持续时间较短,12或24周。为了表征暴露并消除潜在基因毒性降解产物的可能混淆,lorcaserinandN-nitroso-lorcaserinwerequantifiedindosingsolutions,终端血浆,乳腺和肝脏样品使用超高效液相色谱-电喷雾串联质谱。没有检测到N-亚硝基-lorcaserin,支持将lorcaserin分类为非遗传毒性致癌物。乳腺DNA样品(n=6/剂量/时间点)用于从包含热点癌症驱动突变(CDMs)的基因片段合成PCR产物,即Apc的区域,Braf,Egfr,Hras,Kras,Nfe2l2,Pik3ca,Setbp1、Stk11和Tp53。通过CarcSeq定量扩增子中的突变级分(MF),错误校正的下一代测序方法。考虑到所有恢复的突变体,lorcaserin剂量组之间没有观察到显著差异。然而,在两个时间点均观察到Pik3caH1047R突变的显着剂量反应性增加(ANOVA,p<0.05),与12周相比,在24周观察到更多数量的突变体和具有更大MF的突变体。这些观察结果表明,lorcaserin促进自发发生的Pik3caH1047R突变克隆的生长,从而导致乳腺癌发生。重要的是,这项工作报告了分析克隆扩增的方法,并证明了使用短至3个月的治疗时间检测非基因毒性致癌物质的致癌影响(选择性Pik3caH0147R突变体扩增)。
Lorcaserin is a 5-hydroxytryptamine 2C (serotonin) receptor agonist and a non-genotoxic rat carcinogen, which induced mammary tumors in male and female rats in a two-year bioassay. Female Sprague Dawley rats were treated by gavage daily with 0, 30, or 100 mg/kg lorcaserin, replicating bioassay dosing but for shorter duration, 12 or 24 weeks. To characterize exposure and eliminate possible confounding by a potentially genotoxic degradation product, lorcaserin and N-nitroso-lorcaserin were quantified in dosing solutions, terminal plasma, mammary and liver samples using ultra high-performance liquid chromatography-electrospray tandem mass spectrometry. N-nitroso-lorcaserin was not detected, supporting lorcaserin classification as non-genotoxic carcinogen. Mammary DNA samples (n = 6/dose/timepoint) were used to synthesize PCR products from gene segments encompassing hotspot cancer driver mutations (CDMs), namely regions of Apc, Braf, Egfr, Hras, Kras, Nfe2l2, Pik3ca, Setbp1, Stk11, and Tp53. Mutant fractions (MFs) in the amplicons were quantified by CarcSeq, an error corrected next-generation sequencing approach. Considering all recovered mutants, no significant differences between lorcaserin dose groups were observed. However, significant dose-responsive increases in Pik3ca H1047R mutation were observed at both timepoints (ANOVA, p < 0.05), with greater numbers of mutants and mutants with greater MFs observed at 24 weeks as compared to 12 weeks. These observations suggest lorcaserin promotes outgrowth of spontaneously occurring Pik3ca H1047R mutant clones leading to mammary carcinogenesis. Importantly, this work reports approaches to analyze clonal expansion and demonstrates CarcSeq detection of the carcinogenic impact (selective Pik3ca H0147R mutant expansion) of a non-genotoxic carcinogen using a treatment duration as short as 3 months.