RESUMEN
A delicate equilibrium of WNT agonists and antagonists in the intestinal stem cell (ISC) niche is critical to maintaining the ISC compartment, as it accommodates the rapid renewal of the gut lining. Disruption of this balance by mutations in the tumour suppressor gene APC, which are found in approximately 80% of all human colon cancers, leads to unrestrained activation of the WNT pathway1,2. It has previously been established that Apc-mutant cells have a competitive advantage over wild-type ISCs3. Consequently, Apc-mutant ISCs frequently outcompete all wild-type stem cells within a crypt, thereby reaching clonal fixation in the tissue and initiating cancer formation. However, whether the increased relative fitness of Apc-mutant ISCs involves only cell-intrinsic features or whether Apc mutants are actively involved in the elimination of their wild-type neighbours remains unresolved. Here we show that Apc-mutant ISCs function as bona fide supercompetitors by secreting WNT antagonists, thereby inducing differentiation of neighbouring wild-type ISCs. Lithium chloride prevented the expansion of Apc-mutant clones and the formation of adenomas by rendering wild-type ISCs insensitive to WNT antagonists through downstream activation of WNT by inhibition of GSK3ß. Our work suggests that boosting the fitness of healthy cells to limit the expansion of pre-malignant clones may be a powerful strategy to limit the formation of cancers in high-risk individuals.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Competencia Celular , Genes APC , Neoplasias Intestinales/genética , Neoplasias Intestinales/patología , Mutación , Adenoma/genética , Adenoma/metabolismo , Adenoma/patología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Diferenciación Celular/genética , Femenino , Glucógeno Sintasa Quinasa 3 beta/antagonistas & inhibidores , Humanos , Neoplasias Intestinales/metabolismo , Cloruro de Litio/farmacología , Masculino , Ratones , Organoides/citología , Organoides/metabolismo , Organoides/patología , Proteínas Wnt/antagonistas & inhibidores , Proteínas Wnt/metabolismoRESUMEN
Tumor suppressor genes are involved in maintaining genome integrity during reproduction (e.g., meiosis). Thus, deleterious alleles in tumor suppressor-deficient mice would exhibit higher mortality during the perinatal period. A recent aging model proposes that perinatal mortality and age-related deleterious changes might define lifespan. This study aimed to quantitatively understand the relationship between reproduction and lifespan using three established tumor suppressor gene (p53, APC, and RECQL4)-deficient mouse strains with the same C57BL/6 background. Transgenic mice delivered slightly reduced numbers of 1st pups than wild-type mice [ratio: 0.81-0.93 (p = 0.1-0.61)] during a similar delivery period, which suggest that the tumor suppressor gene-deficient mice undergo relatively stable reproduction. However, the transgenic 1st pups died within a few days after birth, resulting in a further reduction in litter size at 3 weeks after delivery compared with that of wild-type mice [ratio: 0.35-0.68 (p = 0.034-0.24)] without sex differences, although the lifespan was variable. Unexpectedly, the significance of reproductive reduction in transgenic mice was decreased at the 2nd or later delivery. Because mice are easily affected by environmental factors, our data underscore the importance of defining reproductive ability through experiments on aging-related reproduction that can reveal a trade-off between fecundity and aging and identify RECQL4 as a novel pleiotropic gene.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Envejecimiento/genética , Fertilidad/genética , RecQ Helicasas/genética , Proteína p53 Supresora de Tumor/genética , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Femenino , Pleiotropía Genética , Masculino , Ratones , Ratones Endogámicos C57BL , RecQ Helicasas/deficiencia , Proteína p53 Supresora de Tumor/deficienciaRESUMEN
COVID-19 (coronavirus disease 2019) patients exhibiting gastrointestinal symptoms are reported to have worse prognosis. Ace2 (angiotensin-converting enzyme 2), the gene encoding the host protein to which SARS-CoV-2 spike proteins bind, is expressed in the gut and therefore may be a target for preventing or reducing severity of COVID-19. Here we test the hypothesis that Ace2 expression in the gastrointestinal and respiratory tracts is modulated by the microbiome. We used quantitative PCR to profile Ace2 expression in germ-free mice, conventional raised specific pathogen-free mice, and gnotobiotic mice colonized with different microbiota. Intestinal Ace2 expression levels were significantly higher in germ-free mice compared to conventional mice. A similar trend was observed in the respiratory tract. Intriguingly, microbiota depletion via antibiotics partially recapitulated the germ-free phenotype, suggesting potential for microbiome-mediated regulation of Ace2 expression. Variability in intestinal Ace2 expression was observed in gnotobiotic mice colonized with different microbiota, partially attributable to differences in microbiome-encoded proteases and peptidases. Together, these data suggest that the microbiome may be one modifiable factor determining COVID-19 infection risk and disease severity.
Asunto(s)
Enzima Convertidora de Angiotensina 2/metabolismo , Colon/enzimología , Microbioma Gastrointestinal , Intestino Delgado/enzimología , Pulmón/enzimología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Enzima Convertidora de Angiotensina 2/genética , Animales , Femenino , Expresión Génica , Interleucina-10/deficiencia , Interleucina-10/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Murine and human invariant natural killer T (iNKT) lymphocytes are activated by α-galactosylceramide (α-GalCer) presented on CD1d. α-GalCer was first described as a lipid that had strong anti-metastatic effects in a mouse melanoma model, and it has subsequently been shown to induce efficient iNKT cell dependent tumor immunity in several tumor models. We have shown that α-GalCer treatment leads to a weak reduction of polyp burden in the autochthonous ApcMin/+ mouse model for human colon cancer, however this treatment resulted in upregulation of the inhibitory receptor PD-1 on iNKT cells. While anti-PD-1 treatment can prevent immune-suppression in other cancer types, human colon cancer is generally resistant to this treatment. Here we have used the ApcMin/+ model to investigate whether a combined treatment with α-GalCer and PD-1 blockade results in improved effects on polyp development. We find that PD-1 expression was high on T cells in polyps and lamina propria (LP) of ApcMin/+ mice compared to polyp free Apc+/+ littermates. Anti-PD-1 treatment alone promoted Tbet expression in iNKT cells and CD4 T cells, but did not significantly reduce polyp numbers. However, the combined treatment with anti-PD-1 and α-GalCer had synergistic effects, resulting in highly significant reduction of polyp numbers in the small and large intestine. Addition of PD-1 blockade to α-GalCer treatment prevented loss of iNKT cells that were skewed towards a TH1-like iNKT1 phenotype specifically in polyps. It also resulted in TH1 skewing and increased granzyme B expression of CD4 T cells. Taken together this demonstrates that a combination of immune stimulation targeting iNKT cells and checkpoint blockade may be a promising approach to develop for improved tumor immunotherapy.
Asunto(s)
Neoplasias del Colon/inmunología , Neoplasias del Colon/prevención & control , Galactosilceramidas/administración & dosificación , Células T Asesinas Naturales/inmunología , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Animales , Anticuerpos Bloqueadores/administración & dosificación , Femenino , Humanos , Mucosa Intestinal/inmunología , Pólipos Intestinales/inmunología , Pólipos Intestinales/prevención & control , Macrófagos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Neoplasias Experimentales/inmunología , Neoplasias Experimentales/prevención & control , Receptor de Muerte Celular Programada 1/inmunología , Linfocitos T Reguladores/inmunología , Células TH1/inmunologíaRESUMEN
Calorie restriction (CR) extends lifespan through several intracellular mechanisms, including increased DNA repair, leading to fewer DNA mutations that cause age-related pathologies. However, it remains unknown how CR acts on mutation retention at the tissue level. Here, we use Cre-mediated DNA recombination of the confetti reporter as proxy for neutral mutations and follow these mutations by intravital microscopy to identify how CR affects retention of mutations in the intestine. We find that CR leads to increased numbers of functional Lgr5+ stem cells that compete for niche occupancy, resulting in slower but stronger stem cell competition. Consequently, stem cells carrying neutral or Apc mutations encounter more wild-type competitors, thus increasing the chance that they get displaced from the niche to get lost over time. Thus, our data show that CR not only affects the acquisition of mutations but also leads to lower retention of mutations in the intestine.
Asunto(s)
Restricción Calórica , Competencia Celular , Intestinos/citología , Mutación/genética , Células Madre/citología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Animales , Recuento de Células , Linaje de la Célula , Femenino , Microscopía Intravital , Masculino , Ratones Endogámicos C57BLRESUMEN
Colorectal cancer initiation and progression result from the accumulation of genetic and epigenetic alterations. Although aberrant gene expression and DNA methylation profiles are considered hallmarks of colorectal cancer development, the precise timing at which these are produced during tumor establishment remains elusive. Here we investigated the early transcriptional and epigenetic changes induced by adenomatous polyposis coli (Apc) inactivation in intestinal crypts. Hyperactivation of the Wnt pathway via Apc inactivation in crypt base columnar intestinal stem cells (ISC) led to their rapid accumulation driven by an impaired molecular commitment to differentiation, which was associated with discrete alterations in DNA methylation. Importantly, inhibiting the enzymes responsible for de novo DNA methylation restored the responsiveness of Apc-deficient intestinal organoids to stimuli regulating the proliferation-to-differentiation transition in ISC. This work reveals that early DNA methylation changes play critical roles in the establishment of the impaired fate decision program consecutive to Apc loss of function. SIGNIFICANCE: This study demonstrates the functional impact of changes in DNA methylation to determine the colorectal cancer cell phenotype following loss of Apc function.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Metilación de ADN , Intestino Delgado/citología , Intestino Delgado/metabolismo , Receptores Acoplados a Proteínas G/biosíntesis , Células Madre/patología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Animales , Diferenciación Celular/fisiología , División Celular/fisiología , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Metilasas de Modificación del ADN/genética , Metilasas de Modificación del ADN/metabolismo , Silenciador del Gen , Intestino Delgado/patología , Ratones , Ratones Endogámicos C57BL , Receptores Acoplados a Proteínas G/genética , Células Madre/metabolismo , Vía de Señalización WntRESUMEN
Sporadic colorectal cancer initiates with mutations in APC or its degradation target ß-catenin, producing TCF-dependent nuclear transcription driving tumorigenesis. The intestinal epithelial receptor, GUCY2C, with its canonical paracrine hormone guanylin, regulates homeostatic signaling along the crypt-surface axis opposing tumorigenesis. Here, we reveal that expression of the guanylin hormone, but not the GUCY2C receptor, is lost at the earliest stages of transformation in APC-dependent tumors in humans and mice. Hormone loss, which silences GUCY2C signaling, reflects transcriptional repression mediated by mutant APC-ß-catenin-TCF programs in the nucleus. These studies support a pathophysiological model of intestinal tumorigenesis in which mutant APC-ß-catenin-TCF transcriptional regulation eliminates guanylin expression at tumor initiation, silencing GUCY2C signaling which, in turn, dysregulates intestinal homeostatic mechanisms contributing to tumor progression. They expand the mechanistic paradigm for colorectal cancer from a disease of irreversible mutations in APC and ß-catenin to one of guanylin hormone loss whose replacement, and reconstitution of GUCY2C signaling, could prevent tumorigenesis.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Neoplasias Colorrectales/patología , Hormonas Gastrointestinales/metabolismo , Mucosa Intestinal/patología , Péptidos Natriuréticos/metabolismo , Receptores de Enterotoxina/metabolismo , Factores de Transcripción TCF/metabolismo , beta Catenina/metabolismo , Proteína de la Poliposis Adenomatosa del Colon/genética , Animales , Línea Celular Tumoral , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Bases de Datos Genéticas/estadística & datos numéricos , Genes Supresores de Tumor , Humanos , Mucosa Intestinal/metabolismo , Ratones , Ratones Noqueados , Comunicación Paracrina , Transducción de SeñalRESUMEN
Loss of the Adenomatous Polyposis Coli (APC) tumor suppressor in colorectal cancer elicits rapid signaling through the Wnt/ß-catenin signaling pathway. In contrast to this well-established role of APC, recent studies from our laboratory demonstrated that APC functions through Wnt-independent pathways to mediate in vitro and in vivo models of breast tumorigenesis. Pancreatic ductal adenocarcinoma (PDAC) has an overall median survival of less than one year with a 5-year survival rate of 7.2%. APC is lost in a subset of pancreatic cancers, but the impact on Wnt signaling or tumor development is unclear. Given the lack of effective treatment strategies for pancreatic cancer, it is important to understand the functional implications of APC loss in pancreatic cancer cell lines. Therefore, the goal of this project is to study how APC loss affects Wnt pathway activation and in vitro tumor phenotypes. Using lentiviral shRNA, we successfully knocked down APC expression in six pancreatic cancer cell lines (AsPC-1, BxPC3, L3.6pl, HPAF-II, Hs 766T, MIA PaCa-2). No changes were observed in localization of ß-catenin or reporter assays to assess ß-catenin/TCF interaction. Despite this lack of Wnt/ß-catenin pathway activation, the majority of APC knockdown cell lines exhibit an increase in cell proliferation. Cell migration assays showed that the BxPC-3 and L3.6pl cells were impacted by APC knockdown, showing faster wound healing in scratch wound assays. Interestingly, APC knockdown had no effect on gemcitabine treatment, which is the standard care for pancreatic cancer. It is important to understand the functional implications of APC loss in pancreatic cancer cells lines, which could be used as a target for therapeutics.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Humanos , Vía de Señalización Wnt/genéticaRESUMEN
Stem cell aging underlies aging-associated disorders, such as steeply increased incidences of tumors and impaired regeneration capacity upon stress. However, whether and how the intestinal stem cells age remains largely unknown. Here we show that intestinal stem cells derived from 24-month-old mice hardly form typical organoids with crypt-villus structures, but rather mainly form big, rounded cysts devoid of differentiated cell types, which mimics the culturing of heterozygous APC-deficient cells from the APCmin mouse line. Further analysis showed that cultured crypts derived from aged mice exhibited reduced expression levels of differentiation genes and higher expression of Wnt target genes. Lowering the concentration of R-spondin-1 in the culture system significantly reduced formation of rounded cysts, accompanied by an increased formation of organoids from crypts derived from old mice. We are the first to uncover that intestinal stem cells derived from old mice harbor significant deficiency in differentiation that can be partially rescued through a reduction in R-spondin-1 exposure. This could be highly relevant to intestinal tumor development and the reduced regeneration potential observed in the aged population. Our study provides the first experimental evidence that an over-responsiveness to Wnt/beta-catenin signaling of aged intestinal stem cells mediates the aging-induced deficiency in differentiation, and could serve as a potential target to ameliorate aging-associated intestinal pathologies.
Asunto(s)
Envejecimiento/metabolismo , Diferenciación Celular , Mucosa Intestinal/metabolismo , Células Madre/metabolismo , Vía de Señalización Wnt , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Envejecimiento/patología , Animales , Mucosa Intestinal/patología , Neoplasias Intestinales/genética , Neoplasias Intestinales/metabolismo , Neoplasias Intestinales/patología , Ratones , Ratones Mutantes , Células Madre/patologíaRESUMEN
Platelets are produced upon profound reorganization of mature megakaryocytes (MK) leading to proplatelet elongation and release into the blood stream, a process termed thrombopoiesis. This highly dynamic process requires microtubules (MT) reorganization by mechanisms that are still incompletely understood. Adenomatous polyposis coli (APC) is a microtubule plus-end tracking protein involved in the regulation of MT in a number of cell systems and its inactivation has been reported to alter hematopoiesis. The aim of our study was to investigate the role of APC in megakaryopoiesis and the final steps of platelet formation. Down-regulation of APC in cultured human MK by RNA interference increased endomitosis and the proportion of cells able to extend proplatelets (68.8% (shAPC1) and 52.5% (shAPC2) vs 28.1% in the control). Similarly an increased ploidy and amplification of the proplatelet network were observed in MK differentiated from Lin- cells of mice with APC-deficiency in the MK lineage. In accordance, these mice exhibited increased platelet counts when compared to wild type mice (1,323 ± 111 vs 919 ± 52 platelets/µL; n = 12 p 0.0033**). Their platelets had a normal size, ultrastructure and number of microtubules coils and their main functions were also preserved. Loss of APC resulted in lower levels of acetylated tubulin and decreased activation of the Wnt signaling pathway. Thus, APC appears as an important regulator of proplatelet formation and overall thrombopoiesis.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Plaquetas/metabolismo , Microtúbulos/metabolismo , Acetilación , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Plaquetas/ultraestructura , Linaje de la Célula , Células Cultivadas , Megacariocitos/citología , Megacariocitos/metabolismo , Megacariocitos/ultraestructura , Ratones Endogámicos C57BL , Ratones Transgénicos , Microtúbulos/ultraestructura , Recuento de Plaquetas , Ploidias , Vía de Señalización WntRESUMEN
High fat diet is implicated in the elevated deoxycholic acid (DCA) in the intestine and correlated with increased colon cancer risk. However, the potential mechanisms of intestinal carcinogenesis by DCA remain unclarified. Here, we investigated the carcinogenic effects and mechanisms of DCA using the intestinal tumour cells and Apcmin/+ mice model. We found that DCA could activate epidermal growth factor receptor (EGFR) and promote the release of EGFR ligand amphiregulin (AREG), but not HB-EGF or TGF-α in intestinal tumour cells. Moreover, ADAM-17 was required in DCA-induced promotion of shedding of AREG and activation of EGFR/Akt signalling pathway. DCA significantly increased the multiplicity of intestinal tumours and accelerated adenoma-carcinoma sequence in Apcmin/+ mice. ADAM-17/EGFR signalling axis was also activated in intestinal tumours of DCA-treated Apcmin/+ mice, whereas no significant change occurred in tumour adjacent tissues after DCA exposure. Conclusively, DCA activated EGFR and promoted intestinal carcinogenesis by ADAM17-dependent ligand release.
Asunto(s)
Proteína ADAM17/genética , Adenoma/genética , Anfirregulina/genética , Ácido Desoxicólico/administración & dosificación , Receptores ErbB/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Intestinales/genética , Proteína ADAM17/metabolismo , Adenoma/inducido químicamente , Adenoma/metabolismo , Adenoma/patología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Anfirregulina/metabolismo , Animales , Carcinogénesis/genética , Carcinogénesis/metabolismo , Carcinogénesis/patología , Línea Celular Tumoral , Células Epiteliales/metabolismo , Células Epiteliales/patología , Receptores ErbB/metabolismo , Células HCT116 , Humanos , Neoplasias Intestinales/inducido químicamente , Neoplasias Intestinales/metabolismo , Neoplasias Intestinales/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Unión Proteica , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de SeñalRESUMEN
Many epithelial stem cell populations follow a pattern of stochastic stem cell divisions called 'neutral drift'. It is hypothesised that neutral competition between stem cells protects against the acquisition of deleterious mutations. Here we use a Porcupine inhibitor to reduce Wnt secretion at a dose where intestinal homoeostasis is maintained despite a reduction of Lgr5+ stem cells. Functionally, there is a marked acceleration in monoclonal conversion, so that crypts become rapidly derived from a single stem cell. Stem cells located further from the base are lost and the pool of competing stem cells is reduced. We tested whether this loss of stem cell competition would modify tumorigenesis. Reduction of Wnt ligand secretion accelerates fixation of Apc-deficient cells within the crypt leading to accelerated tumorigenesis. Therefore, ligand-based Wnt signalling influences the number of stem cells, fixation speed of Apc mutations and the speed and likelihood of adenoma formation.
Asunto(s)
Carcinogénesis/metabolismo , Transformación Celular Neoplásica/metabolismo , Mucosa Intestinal/citología , Mucosa Intestinal/metabolismo , Células Madre/citología , Células Madre/metabolismo , Vía de Señalización Wnt , Aciltransferasas/antagonistas & inhibidores , Adenoma/etiología , Adenoma/metabolismo , Adenoma/patología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Animales , Carcinogénesis/efectos de los fármacos , Transformación Celular Neoplásica/efectos de los fármacos , Neoplasias Colorrectales/etiología , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Inhibidores Enzimáticos/farmacología , Mucosa Intestinal/efectos de los fármacos , Ligandos , Proteínas de la Membrana/antagonistas & inhibidores , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Pirazinas/farmacología , Piridinas/farmacología , Células Madre/efectos de los fármacos , Vía de Señalización Wnt/efectos de los fármacosRESUMEN
Dietary habits that can induce inflammatory bowel disease (IBD) are major colorectal cancer (CRC) risk factors, but mechanisms linking nutrients, IBD, and CRC are unknown. Using human data and mouse models, we show that mTORC1 inactivation-induced chromosomal instability impairs intestinal crypt proliferation and regeneration, CDK4/6 dependently. This triggers interleukin (IL)-6-associated reparative inflammation, inducing crypt hyper-proliferation, wound healing, and CRC. Blocking IL-6 signaling or reactivating mTORC1 reduces inflammation-induced CRC, so mTORC1 activation suppresses tumorigenesis in IBD. Conversely, mTORC1 inactivation is beneficial in APC loss-dependent CRC. Thus, IL-6 blockers or protein-rich-diet-linked mTORC1 activation may prevent IBD-associated CRC. However, abolishing mTORC1 can mitigate CRC in predisposed patients with APC mutations. Our work reveals mTORC1 oncogenic and tumor-suppressive roles in intestinal epithelium and avenues to optimized and personalized therapeutic regimens for CRC.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Carcinogénesis/patología , Colitis/complicaciones , Neoplasias Colorrectales/etiología , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Adenoma/patología , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Carcinogénesis/metabolismo , Proliferación Celular , Inestabilidad Cromosómica , Daño del ADN , Femenino , Células HCT116 , Homeostasis , Humanos , Inflamación/patología , Enfermedades Inflamatorias del Intestino/metabolismo , Enfermedades Inflamatorias del Intestino/patología , Interleucina-6/metabolismo , Intestinos/patología , Masculino , Proteínas Nucleares/metabolismo , Proteínas de Unión al ARN/metabolismo , Regeneración , Transducción de Señal , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Primary aldosteronism (PA) is a common form of endocrine hypertension that is characterized by the excessive production of aldosterone relative to suppressed plasma renin levels. PA is usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations have been identified in several genes that encode ion pumps and channels that may explain the aldosterone excess in over half of aldosterone-producing adenomas, whereas the pathophysiology of bilateral adrenal hyperplasia is largely unknown. A number of mouse models of hyperaldosteronism have been described that recreate some features of the human disorder, although none replicate the genetic basis of human PA. Animal models that reproduce the genotype-phenotype associations of human PA are required to establish the functional mechanisms that underlie the endocrine autonomy and deregulated cell growth of the affected adrenal and for preclinical studies of novel therapeutics. Herein, we discuss the differences in adrenal physiology across species and describe the genetically modified mouse models of PA that have been developed to date.
Asunto(s)
Glándulas Suprarrenales/fisiología , Glándulas Suprarrenales/fisiopatología , Modelos Animales de Enfermedad , Hiperaldosteronismo/fisiopatología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Glándulas Suprarrenales/metabolismo , Animales , Criptocromos/deficiencia , Criptocromos/genética , Humanos , Hiperaldosteronismo/genética , Hiperaldosteronismo/metabolismo , Subunidades alfa de los Canales de Potasio de Gran Conductancia Activados por Calcio/deficiencia , Subunidades alfa de los Canales de Potasio de Gran Conductancia Activados por Calcio/genética , Ratones Noqueados , Ratones Transgénicos , Canales de Potasio/deficiencia , Canales de Potasio/genética , Canales de Potasio de Dominio Poro en Tándem/deficiencia , Canales de Potasio de Dominio Poro en Tándem/genética , Especificidad de la EspecieRESUMEN
Incidences of infection-related cancers are on the rise in developing countries where the prevalence of intestinal nematode worm infections are also high. Trichuris muris (T. muris) is a murine gut-dwelling nematode that is the direct model for human T. trichiura, one of the major soil-transmitted helminth infections of humans. In order to assess whether chronic infection with T. muris does indeed influence the development of cancer hallmarks, both wild type mice and colon cancer model (APC min/+) mice were infected with this parasite. Parasite infection in wild type mice led to the development of neoplastic change similar to that seen in mice that had been treated with the carcinogen azoxymethane. Additionally, both chronic and acute infection in the APCmin/+ mice led to an enhanced tumour development that was distinct to the site of infection suggesting systemic control. By blocking the parasite induced T regulatory response in these mice, the increase in the number of tumours following infection was abrogated. Thus T. muris infection alone causes an increase in gut pathologies that are known to be markers of cancer but also increases the incidence of tumour formation in a colon cancer model. The influence of parasitic worm infection on the development of cancer may therefore be significant.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Carcinogénesis , Neoplasias del Colon/epidemiología , Tricuriasis/complicaciones , Trichuris/patogenicidad , Proteína de la Poliposis Adenomatosa del Colon/genética , Animales , Enfermedad Crónica , Neoplasias del Colon/etiología , Modelos Animales de Enfermedad , Incidencia , RatonesRESUMEN
Osteopontin (OPN) is a secreted phosphoglycoprotein, and is a transcriptional target of aberrant Wnt signaling. OPN is upregulated in human colon cancers, and is suggested to enhance cancer progression. In this study, the effect of deficiency of OPN on intestinal tumor development in Apc-deficient Min mice was investigated. At 16 weeks of age, the number of small intestinal polyps in Min/OPN(+/-) and Min/OPN(-/-) mice was lower than that of Min/OPN(+/+) mice. Colorectal tumor incidences and multiplicities in Min/OPN(+/-) and Min/OPN(-/-) mice were significantly lower than those in Min/OPN(+/+) mice, being 48% and 0.6 ± 0.8, 50% and 0.8 ± 0.9 vs. 80% and 1.6 ± 1.7, respectively. OPN expression in colorectal tumors was strongly upregulated in Min/OPN(+/+) compared to adjacent non-tumor parts, but was decreased in Min/OPN(+/-) and not detected in Min/OPN(-/-). Targets of OPN, matrix metalloproteinases (MMPs)-3, -9, and -13 were lowered by OPN deficiency. Macrophage marker F4/80 in colorectal tumors was also lowered by OPN deficiency. MMP-9 expression was observed in tumor cells and tumor-infiltrating neutrophils. These results indicate that induction of OPN by aberrant Wnt signaling could enhance colorectal tumor development in part by upregulation of MMP-3, -9, and -13 and infiltration of macrophage and neutrophils. Suppression of OPN expression could contribute to tumor prevention, but complete deficiency of OPN may cause some adverse effects.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Proliferación Celular/genética , Neoplasias Intestinales/genética , Osteopontina/genética , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Intestinales/patología , Pólipos Intestinales/genética , Pólipos Intestinales/patología , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/genética , Ratones , Ratones Noqueados , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Osteopontina/deficiencia , Vía de Señalización Wnt/genéticaRESUMEN
Elucidating signaling pathways that regulate cellular metabolism is essential for a better understanding of normal development and tumorigenesis. Recent studies have shown that mitochondrial pyruvate carrier 1 (MPC1), a crucial player in pyruvate metabolism, is downregulated in colon adenocarcinomas. Utilizing zebrafish to examine the genetic relationship between MPC1 and Adenomatous polyposis coli (APC), a key tumor suppressor in colorectal cancer, we found that apc controls the levels of mpc1 and that knock down of mpc1 recapitulates phenotypes of impaired apc function including failed intestinal differentiation. Exogenous human MPC1 RNA rescued failed intestinal differentiation in zebrafish models of apc deficiency. Our data demonstrate a novel role for apc in pyruvate metabolism and that pyruvate metabolism dictates intestinal cell fate and differentiation decisions downstream of apc.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Carcinogénesis , Regulación de la Expresión Génica , Intestinos/fisiología , Proteínas de Transporte de Membrana Mitocondrial/genética , Ácido Pirúvico/metabolismo , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Humanos , Redes y Vías Metabólicas , Modelos Animales , Transportadores de Ácidos Monocarboxílicos , Pez CebraRESUMEN
Inflammation and microbiota are critical components of intestinal tumorigenesis. To dissect how the microbiota contributes to tumor distribution, we generated germ-free (GF) ApcMin/+ and ApcMin/+ ;Il10-/- mice and exposed them to specific-pathogen-free (SPF) or colorectal cancer-associated bacteria. We found that colon tumorigenesis significantly correlated with inflammation in SPF-housed ApcMin/+ ;Il10-/- , but not in ApcMin/+ mice. In contrast, small intestinal neoplasia development significantly correlated with age in both ApcMin/+ ;Il10-/- and ApcMin/+ mice. GF ApcMin/+ ;Il10-/- mice conventionalized by an SPF microbiota had significantly more colon tumors compared with GF mice. Gnotobiotic studies revealed that while Fusobacterium nucleatum clinical isolates with FadA and Fap2 adhesins failed to induce inflammation and tumorigenesis, pks+Escherichia coli promoted tumorigenesis in the ApcMin/+ ;Il10-/- model in a colibactin-dependent manner, suggesting colibactin is a driver of carcinogenesis. Our results suggest a distinct etiology of cancers in different locations of the gut, where colon cancer is primarily driven by inflammation and the microbiome, while age is a driving force for small intestine cancer. Cancer Res; 77(10); 2620-32. ©2017 AACR.
Asunto(s)
Transformación Celular Neoplásica , Neoplasias Colorrectales/etiología , Neoplasias Colorrectales/patología , Microbioma Gastrointestinal , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Bacterias/clasificación , Bacterias/genética , Modelos Animales de Enfermedad , Inflamación/complicaciones , Inflamación/patología , Interleucina-10/deficiencia , Ratones , Ratones Noqueados , Ratones TransgénicosRESUMEN
Obesity is a major risk factor for colorectal cancer and can accelerate Lgr5+ intestinal stem cell (ISC)-derived tumorigenesis after the inactivation of Apc However, whether non-canonical pathways involving PI3K-Akt signaling in ISCs can lead to tumor formation, and if this can be further exacerbated by obesity is unknown. Despite the synergy between Pten and Apc inactivation in epithelial cells on intestinal tumor formation, their combined role in Lgr5+-ISCs, which are the most rapidly dividing ISC population in the intestine, is unknown. Lgr5+-GFP mice were provided low-fat diet (LFD) or high-fat diet (HFD) for 8 months, and the transcriptome was evaluated in Lgr5+-ISCs. For tumor studies, Lgr5+-GFP and Lgr5+-GFP-Ptenflox/flox mice were tamoxifen treated to inactivate Pten in ISCs and provided LFD or HFD until 14-15 months of age. Finally, various combinations of Lgr5+-ISC-specific, Apc- and Pten-deleted mice were generated and evaluated for histopathology and survival. HFD did not overtly alter Akt signaling in ISCs, but did increase other metabolic pathways. Pten deficiency, but not HFD, increased BrdU-positive cells in the small intestine (P < 0.05). However, combining Pten and Apc deficiency synergistically increased proliferative markers, tumor pathology and mortality, in a dose-dependent fashion (P < 0.05). In summary, we show that HFD alone fails to drive Akt signaling in ISCs and that Pten deficiency is dispensable as a tumor suppressor in Lgr5+-ISCs. However, combining Pten and Apc deficiency in ISCs synergistically increases proliferation, tumor formation and mortality. Thus, aberrant Wnt/ß-catenin, rather than PI3K-Akt signaling, is requisite for obesity to drive Lgr5+ ISC-derived tumorigenesis.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Carcinogénesis/genética , Obesidad/genética , Fosfohidrolasa PTEN/genética , Células Madre/patología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Animales , Dieta con Restricción de Grasas , Dieta Alta en Grasa , Tracto Gastrointestinal/citología , Tracto Gastrointestinal/patología , Glucosa/análisis , Proteínas Fluorescentes Verdes/genética , Insulina/sangre , Masculino , Ratones Transgénicos , Obesidad/sangre , Fosfohidrolasa PTEN/deficiencia , Receptores Acoplados a Proteínas G/genéticaRESUMEN
Wnt signaling, named after the secreted proteins that bind to cell surface receptors to activate the pathway, plays critical roles both in embryonic development and the maintenance of homeostasis in many adult tissues. Two particularly important cellular programs orchestrated by Wnt signaling are proliferation and stem cell self-renewal. Constitutive activation of the Wnt pathway resulting from mutation or improper modulation of pathway components contributes to cancer development in various tissues. Colon cancers frequently bear inactivating mutations of the adenomatous polyposis coli (APC) gene, whose product is an important component of the destruction complex that regulates ß-catenin levels. Stabilization and nuclear localization of ß-catenin result in the expression of a panel of Wnt target genes. We previously showed that Mule/Huwe1/Arf-BP1 (Mule) controls murine intestinal stem and progenitor cell proliferation by modulating the Wnt pathway via c-Myc. Here we extend our investigation of Mule's influence on oncogenesis by showing that Mule interacts directly with ß-catenin and targets it for degradation under conditions of hyperactive Wnt signaling. Our findings suggest that Mule uses various mechanisms to fine-tune the Wnt pathway and provides multiple safeguards against tumorigenesis.