RESUMEN
Irinotecan is a widely used topoisomerase-I-inhibitor with a very narrow therapeutic window because of its severe toxicity. In the current study we have examined the effects of fasting prior to irinotecan treatment on toxicity and anti-tumor activity. FabplCre;Apc(15lox/+) mice, which spontaneously develop intestinal tumors, of 27 weeks of age were randomized into 3-day fasted and ad libitum fed groups, followed by treatment with a flat-fixed high dose of irinotecan or vehicle. Side-effects were recorded until 11 days after the start of the experiment. Tumor size, and markers for cell-cycle activity, proliferation, angiogenesis, and senescence were measured. Fasted mice were protected against the side-effects of irinotecan treatment. Ad libitum fed mice developed visible signs of discomfort including weight loss, lower activity, ruffled coat, hunched-back posture, diarrhea, and leukopenia. Irinotecan reduced tumor size in fasted and ad libitum fed groups similarly compared to untreated controls (2.4 ± 0.67 mm and 2.4 ± 0.82 mm versus 3.0 ± 1.05 mm and 2.8 ± 1.08 mm respectively, P < 0.001). Immunohistochemical analysis showed reduced proliferation, a reduced number of vascular endothelial cells, and increased levels of senescence in tumors of both irinotecan treated groups. In conclusion, 3 days of fasting protects against the toxic side-effects of irinotecan in a clinically relevant mouse model of spontaneously developing colorectal cancer without affecting its anti-tumor activity. These results support fasting as a powerful way to improve treatment of colorectal carcinoma patients.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Camptotecina/análogos & derivados , Ayuno , Inhibidores de Topoisomerasa I/efectos adversos , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Camptotecina/efectos adversos , Camptotecina/uso terapéutico , Camptotecina/toxicidad , Proliferación Celular/efectos de los fármacos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Modelos Animales de Enfermedad , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Irinotecán , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Puntos de Control de la Fase S del Ciclo Celular/efectos de los fármacos , Inhibidores de Topoisomerasa I/uso terapéuticoRESUMEN
The cyclin dependent kinase (CDK) inhibitors p15, p16, p21, and p27 are frequently deleted, silenced, or downregulated in many malignancies. Inactivation of CDK inhibitors predisposes mice to tumor development, showing that these genes function as tumor suppressors. Here, we describe high-throughput murine leukemia virus insertional mutagenesis screens in mice that are deficient for one or two CDK inhibitors. We retrieved 9,117 retroviral insertions from 476 lymphomas to define hundreds of loci that are mutated more frequently than expected by chance. Many of these loci are skewed toward a specific genetic context of predisposing germline and somatic mutations. We also found associations between these loci with gender, age of tumor onset, and lymphocyte lineage (B or T cell). Comparison of retroviral insertion sites with single nucleotide polymorphisms associated with chronic lymphocytic leukemia revealed a significant overlap between the datasets. Together, our findings highlight the importance of genetic context within large-scale mutation detection studies, and they show a novel use for insertional mutagenesis data in prioritizing disease-associated genes that emerge from genome-wide association studies.
Asunto(s)
Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/genética , Mutagénesis Insercional/genética , Neoplasias Experimentales/genética , Animales , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/deficiencia , Inhibidor p15 de las Quinasas Dependientes de la Ciclina/deficiencia , Inhibidor p15 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/deficiencia , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/deficiencia , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/deficiencia , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/genética , Femenino , Virus de la Leucemia Murina/genética , Leucemia Linfocítica Crónica de Células B/genética , Linfoma/genética , Masculino , Ratones , Células 3T3 NIH , Polimorfismo de Nucleótido SimpleRESUMEN
p53 and p19(ARF) are tumor suppressors frequently mutated in human tumors. In a high-throughput screen in mice for mutations collaborating with either p53 or p19(ARF) deficiency, we identified 10,806 retroviral insertion sites, implicating over 300 loci in tumorigenesis. This dataset reveals 20 genes that are specifically mutated in either p19(ARF)-deficient, p53-deficient or wild-type mice (including Flt3, mmu-mir-106a-363, Smg6, and Ccnd3), as well as networks of significant collaborative and mutually exclusive interactions between cancer genes. Furthermore, we found candidate tumor suppressor genes, as well as distinct clusters of insertions within genes like Flt3 and Notch1 that induce mutants with different spectra of genetic interactions. Cross species comparative analysis with aCGH data of human cancer cell lines revealed known and candidate oncogenes (Mmp13, Slamf6, and Rreb1) and tumor suppressors (Wwox and Arfrp2). This dataset should prove to be a rich resource for the study of genetic interactions that underlie tumorigenesis.