RESUMEN
Primary cilia are antenna-like organelles which sense extracellular cues and act as signalling hubs. Cilia dysfunction causes a heterogeneous group of disorders known as ciliopathy syndromes affecting most organs. Cilia disassembly, the process by which cells lose their cilium, is poorly understood but frequently observed in disease and upon cell transformation. Here, we uncover a role for the PI3Kα signalling enzyme in cilia disassembly. Genetic PI3Kα-hyperactivation, as observed in PIK3CA-related overgrowth spectrum (PROS) and cancer, induced a ciliopathy-like phenotype during mouse development. Mechanistically, PI3Kα and PI3Kß produce the PIP3 lipid at the cilia transition zone upon disassembly stimulation. PI3Kα activation initiates cilia disassembly through a kinase signalling axis via the PDK1/PKCι kinases, the CEP170 centrosomal protein and the KIF2A microtubule-depolymerising kinesin. Our data suggest diseases caused by PI3Kα-activation may be considered 'Disorders with Ciliary Contributions', a recently-defined subset of ciliopathies in which some, but not all, of the clinical manifestations result from cilia dysfunction.
Asunto(s)
Cilios , Fosfatidilinositol 3-Quinasa Clase I , Transducción de Señal , Cilios/metabolismo , Animales , Ratones , Humanos , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Fosfatidilinositol 3-Quinasa Clase I/genética , Ciliopatías/metabolismo , Ciliopatías/genética , Ciliopatías/patología , Cinesinas/metabolismo , Cinesinas/genéticaRESUMEN
RATIONALE: Delivering optimal patient health care requires interdisciplinary clinician communication. A single communication tool across multiple pre-hospital and hospital settings, and between hospital departments is a novel solution to current systems. Fit-for-purpose, secure smartphone applications allow clinical information to be shared quickly between health providers. Little is known as to what underpins their successful implementation in an emergency care context. AIMS: To identify (a) whether implementing a single, digital health communication application across multiple health care organisations and hospital departments is feasible; (b) the barriers and facilitators to implementation; and (c) which factors are associated with clinicians' intentions to use the technology. METHODS: We used a multimethod design, evaluating the implementation of a secure, digital communication application (Pulsara™). The technology was trialled in two Australian regional hospitals and 25 Ambulance Victoria branches (AV). Post-training, clinicians involved in treating patients with suspected stroke or cardiac events were administered surveys measuring perceived organisational readiness (Organisational Readiness for Implementing Change), clinicians' intentions (Unified Theory of Acceptance and Use of Technology) and internal motivations (Self-Determination Theory) to use Pulsara™, and the perceived benefits and barriers of use. Quantitative data were descriptively summarised with multivariable associations between factors and intentions to use Pulsara™ examined with linear regression. Qualitative data responses were subjected to directed content analysis (two coders). RESULTS: Participants were paramedics (n = 82, median 44 years) or hospital-based clinicians (n = 90, median 37 years), with organisations perceived to be similarly ready. Regression results (F(11, 136) = 21.28, p = <0.001, Adj R2 = 0.60) indicated Habit, Effort Expectancy, Perceived Organisational Readiness, Performance Expectancy and Organisation membership (AV) as predictors of intending to use Pulsara™. Themes relating to benefits (95% coder agreement) included improved communication, procedural efficiencies and faster patient care. Barriers (92% coder agreement) included network accessibility and remembering passwords. PulsaraTM was initiated 562 times. CONCLUSION: Implementing multiorganisational, digital health communication applications is feasible, and facilitated when organisations are change-ready for an easy-to-use, effective solution. Developing habitual use is key, supported through implementation strategies (e.g., hands-on training). Benefits should be emphasised (e.g., during education sessions), including streamlining communication and patient flow, and barriers addressed (e.g., identify champions and local technical support) at project commencement.
Asunto(s)
Servicios Médicos de Urgencia , Comunicación Interdisciplinaria , Humanos , Salud Digital , Australia , Atención a la SaludRESUMEN
PTEN is one of the most commonly inactivated tumour suppressor genes in sporadic cancer. Germline heterozygous PTEN gene alterations also underlie PTEN hamartoma tumour syndrome (PHTS), a rare human cancer-predisposition condition. A key feature of systemic PTEN deregulation is the inability to adequately dampen PI3-kinase (PI3K)/mTORC1 signalling. PI3K/mTORC1 pathway inhibitors such as rapamycin are therefore expected to neutralise the impact of PTEN loss, rendering this a more druggable context compared with those of other tumour suppressor pathways such as loss of TP53. However, this has not been explored in cancer prevention in a model of germline cancer predisposition, such as PHTS. Clinical trials of short-term treatment with rapamycin have recently been initiated for PHTS, focusing on cognition and colon polyposis. Here, we administered a low dose of rapamycin from the age of 6 weeks onwards to mice with heterozygous germline Pten loss, a mouse model that recapitulates most characteristics of human PHTS. Rapamycin was well tolerated and led to a highly significant improvement of survival in both male and female mice. This was accompanied by a delay in, but not full blockade of, the development of a range of proliferative lesions, including gastro-intestinal and thyroid tumours and endometrial hyperplasia, with no impact on mammary and prostate tumours, and no effect on brain overgrowth. Our data indicate that rapamycin may have cancer prevention potential in human PHTS. This might also be the case for sporadic cancers in which genetic PI3K pathway activation is an early event in tumour development, such as endometrial cancer and some breast cancers. To the best of our knowledge, this is the first report of a long-term treatment of a germline cancer predisposition model with a PI3K/mTOR pathway inhibitor. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Asunto(s)
Síndrome de Hamartoma Múltiple , Neoplasias de la Tiroides , Ratones , Animales , Masculino , Femenino , Humanos , Lactante , Sirolimus/farmacología , Sirolimus/uso terapéutico , Fosfatidilinositol 3-Quinasas/genética , Longevidad , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Síndrome de Hamartoma Múltiple/tratamiento farmacológico , Síndrome de Hamartoma Múltiple/genética , Síndrome de Hamartoma Múltiple/patología , Fosfatidilinositol 3-Quinasa/genética , Inhibidores de las Quinasa Fosfoinosítidos-3 , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Células Germinativas/metabolismo , Mutación de Línea GerminalRESUMEN
OBJECTIVES: To determine if a digital communication app improves care timelines for patients with suspected acute stroke/ST-elevation myocardial infarction (STEMI). DESIGN: Real-world feasibility study, quasi-experimental design. SETTING: Prehospital (25 Ambulance Victoria branches) and within-hospital (2 hospitals) in regional Victoria, Australia. PARTICIPANTS: Paramedics or emergency department (ED) clinicians identified patients with suspected acute stroke (onset <4.5 hours; n=604) or STEMI (n=247). INTERVENTION: The Pulsara communication app provides secure, two-way, real-time communication. Assessment and treatment times were recorded for 12 months (May 2017-April 2018), with timelines compared between 'Pulsara initiated' (Pulsara) and 'not initiated' (no Pulsara). PRIMARY OUTCOME MEASURE: Door-to-treatment (needle for stroke, balloon for STEMI) Secondary outcome measures: ambulance and hospital processes. RESULTS: Stroke (no Pulsara n=215, Pulsara n=389) and STEMI (no Pulsara n=76, Pulsara n=171) groups were of similar age and sex (stroke: 76 vs 75 years; both groups 50% male; STEMI: 66 vs 63 years; 68% and 72% male). When Pulsara was used, patients were off ambulance stretcher faster for stroke (11(7, 17) vs 19(11, 29); p=0.0001) and STEMI (14(7, 23) vs 19(10, 32); p=0.0014). ED door-to-first medical review was faster (6(2, 14) vs 23(8, 67); p=0.0001) for stroke but only by 1 min for STEMI (3 (0, 7) vs 4 (0, 14); p=0.25). Door-to-CT times were 44 min faster (27(18, 44) vs 71(43, 147); p=0.0001) for stroke, and percutaneous intervention door-to-balloon times improved by 17 min, but non-significant (56 (34, 88) vs 73 (49, 110); p=0.41) for STEMI. There were improvements in the proportions of patients treated within 60 min for stroke (12%-26%, p=0.15) and 90 min for STEMI (50%-78%, p=0.20). CONCLUSIONS: In this Australian-first study, uptake of the digital communication app was strong, patient-centred care timelines improved, although door-to-treatment times remained similar.
Asunto(s)
Servicios Médicos de Urgencia , Aplicaciones Móviles , Infarto del Miocardio , Infarto del Miocardio con Elevación del ST , Accidente Cerebrovascular , Ambulancias , Arritmias Cardíacas , Comunicación , Electrocardiografía , Estudios de Factibilidad , Femenino , Humanos , Masculino , Infarto del Miocardio/terapia , Infarto del Miocardio con Elevación del ST/terapia , Accidente Cerebrovascular/terapia , Factores de Tiempo , Resultado del Tratamiento , VictoriaRESUMEN
Nasopharyngeal cancer (NPC), endemic in Southeast Asia, lacks effective diagnostic and therapeutic strategies. Even in high-income countries the 5-year survival rate for stage IV NPC is less than 40%. Here we report high somatostatin receptor 2 (SSTR2) expression in multiple clinical cohorts comprising 402 primary, locally recurrent and metastatic NPCs. We show that SSTR2 expression is induced by the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) via the NF-κB pathway. Using cell-based and preclinical rodent models, we demonstrate the therapeutic potential of SSTR2 targeting using a cytotoxic drug conjugate, PEN-221, which is found to be superior to FDA-approved SSTR2-binding cytostatic agents. Furthermore, we reveal significant correlation of SSTR expression with increased rates of survival and report in vivo uptake of the SSTR2-binding 68Ga-DOTA-peptide radioconjugate in PET-CT scanning in a clinical trial of NPC patients (NCT03670342). These findings reveal a key role in EBV-associated NPC for SSTR2 in infection, imaging, targeted therapy and survival.
Asunto(s)
Infecciones por Virus de Epstein-Barr , Regulación Neoplásica de la Expresión Génica , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas , Recurrencia Local de Neoplasia , Receptores de Somatostatina , Proteínas de la Matriz Viral , Animales , Femenino , Humanos , Masculino , Ratones , Antineoplásicos/farmacología , Línea Celular Tumoral , Infecciones por Virus de Epstein-Barr/tratamiento farmacológico , Infecciones por Virus de Epstein-Barr/genética , Infecciones por Virus de Epstein-Barr/mortalidad , Infecciones por Virus de Epstein-Barr/virología , Herpesvirus Humano 4/efectos de los fármacos , Herpesvirus Humano 4/crecimiento & desarrollo , Herpesvirus Humano 4/patogenicidad , Interacciones Huésped-Patógeno/genética , Metástasis Linfática , Ratones Desnudos , Terapia Molecular Dirigida , Carcinoma Nasofaríngeo/tratamiento farmacológico , Carcinoma Nasofaríngeo/genética , Carcinoma Nasofaríngeo/mortalidad , Carcinoma Nasofaríngeo/virología , Neoplasias Nasofaríngeas/tratamiento farmacológico , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/mortalidad , Neoplasias Nasofaríngeas/virología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/virología , FN-kappa B/genética , FN-kappa B/metabolismo , Octreótido/farmacología , Tomografía Computarizada por Tomografía de Emisión de Positrones , Receptores de Somatostatina/antagonistas & inhibidores , Receptores de Somatostatina/genética , Receptores de Somatostatina/metabolismo , Transducción de Señal , Análisis de Supervivencia , Proteínas de la Matriz Viral/antagonistas & inhibidores , Proteínas de la Matriz Viral/genética , Proteínas de la Matriz Viral/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The PIK3CA gene, which encodes the p110α catalytic subunit of PI3 kinase (PI3K), is mutationally activated in cancer and in overgrowth disorders known as PIK3CA-related overgrowth spectrum (PROS). To determine the consequences of genetic PIK3CA activation in a developmental context of relevance to both PROS and cancer, we engineered isogenic human induced pluripotent stem cells (iPSCs) with heterozygous or homozygous knockin of PIK3CAH1047R While heterozygous iPSCs remained largely similar to wild-type cells, homozygosity for PIK3CAH1047R caused widespread, cancer-like transcriptional remodeling, partial loss of epithelial morphology, up-regulation of stemness markers, and impaired differentiation to all three germ layers in vitro and in vivo. Genetic analysis of PIK3CA-associated cancers revealed that 64% had multiple oncogenic PIK3CA copies (39%) or additional PI3K signaling pathway-activating "hits" (25%). This contrasts with the prevailing view that PIK3CA mutations occur heterozygously in cancer. Our findings suggest that a PI3K activity threshold determines pathological consequences of oncogenic PIK3CA activation and provide insight into the specific role of this pathway in human pluripotent stem cells.
Asunto(s)
Fosfatidilinositol 3-Quinasa Clase I , Células Madre Pluripotentes Inducidas , Neoplasias , Adolescente , Línea Celular Tumoral , Fosfatidilinositol 3-Quinasa Clase I/genética , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Fosfatidilinositol 3-Quinasa Clase I/fisiología , Femenino , Edición Génica , Regulación Neoplásica de la Expresión Génica/genética , Técnicas de Sustitución del Gen , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/fisiología , Masculino , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Transducción de Señal/genéticaRESUMEN
Vps34 PI3K is thought to be the main producer of phosphatidylinositol-3-monophosphate, a lipid that controls intracellular vesicular trafficking. The organismal impact of systemic inhibition of Vps34 kinase activity is not completely understood. Here we show that heterozygous Vps34 kinase-dead mice are healthy and display a robustly enhanced insulin sensitivity and glucose tolerance, phenotypes mimicked by a selective Vps34 inhibitor in wild-type mice. The underlying mechanism of insulin sensitization is multifactorial and not through the canonical insulin/Akt pathway. Vps34 inhibition alters cellular energy metabolism, activating the AMPK pathway in liver and muscle. In liver, Vps34 inactivation mildly dampens autophagy, limiting substrate availability for mitochondrial respiration and reducing gluconeogenesis. In muscle, Vps34 inactivation triggers a metabolic switch from oxidative phosphorylation towards glycolysis and enhanced glucose uptake. Our study identifies Vps34 as a new drug target for insulin resistance in Type-2 diabetes, in which the unmet therapeutic need remains substantial.
Asunto(s)
Resistencia a la Insulina , Mitocondrias/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Transducción de Señal/fisiología , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , Autofagia/fisiología , Línea Celular Tumoral , Fosfatidilinositol 3-Quinasas Clase III , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Técnicas de Sustitución del Gen , Glucosa/análisis , Glucosa/metabolismo , Prueba de Tolerancia a la Glucosa , Glucólisis/fisiología , Hepatocitos , Heterocigoto , Humanos , Insulina/metabolismo , Hígado/citología , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Animales , Músculo Esquelético/citología , Músculo Esquelético/metabolismo , Mioblastos , Fosfatidilinositol 3-Quinasas/genética , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación , Cultivo Primario de CélulasRESUMEN
Mutations in PIK3CA are very frequent in cancer and lead to sustained PI3K pathway activation. The impact of acute expression of mutant PIK3CA during early stages of malignancy is unknown. Using a mouse model to activate the Pik3ca H1047R hotspot mutation in the heterozygous state from its endogenous locus, we here report that mutant Pik3ca induces centrosome amplification in cultured cells (through a pathway involving AKT, ROCK and CDK2/Cyclin E-nucleophosmin) and in mouse tissues, and increased in vitro cellular tolerance to spontaneous genome doubling. We also present evidence that the majority of PIK3CA H1047R mutations in the TCGA breast cancer cohort precede genome doubling. These previously unappreciated roles of PIK3CA mutation show that PI3K signalling can contribute to the generation of irreversible genomic changes in cancer. While this can limit the impact of PI3K-targeted therapies, these findings also open the opportunity for therapeutic approaches aimed at limiting tumour heterogeneity and evolution.
Asunto(s)
Neoplasias de la Mama/enzimología , Neoplasias de la Mama/genética , Centrosoma/metabolismo , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Amplificación de Genes , Genoma , Fosfatidilinositol 3-Quinasas/metabolismo , Animales , Fosfatidilinositol 3-Quinasa Clase I/genética , Estudios de Cohortes , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Mutación , Oncogenes , Fosfatidilinositol 3-Quinasas/genéticaRESUMEN
AIMS/HYPOTHESIS: While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2ß and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2ß increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. METHODS: We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). RESULTS: While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. CONCLUSIONS/INTERPRETATION: Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. ACCESS TO RESEARCH MATERIALS: All reagents are available upon request.
Asunto(s)
Resistencia a la Insulina/fisiología , Leptina/metabolismo , Obesidad/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Adipocitos/metabolismo , Animales , Western Blotting , Línea Celular , Ingestión de Alimentos/genética , Ingestión de Alimentos/fisiología , Glucosa/metabolismo , Homeostasis/genética , Homeostasis/fisiología , Hipotálamo/metabolismo , Insulina/metabolismo , Resistencia a la Insulina/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad/genética , Fosfatidilinositol 3-Quinasas/genética , Transducción de Señal/genética , Transducción de Señal/fisiologíaRESUMEN
Venous malformations (VMs) are painful and deforming vascular lesions composed of dilated vascular channels, which are present from birth. Mutations in the TEK gene, encoding the tyrosine kinase receptor TIE2, are found in about half of sporadic (nonfamilial) VMs, and the causes of the remaining cases are unknown. Sclerotherapy, widely accepted as first-line treatment, is not fully efficient, and targeted therapy for this disease remains underexplored. We have generated a mouse model that faithfully mirrors human VM through mosaic expression of Pik3ca(H1047R), a constitutively active mutant of the p110α isoform of phosphatidylinositol 3-kinase (PI3K), in the embryonic mesoderm. Endothelial expression of Pik3ca(H1047R)resulted in endothelial cell (EC) hyperproliferation, reduction in pericyte coverage of blood vessels, and decreased expression of arteriovenous specification markers. PI3K pathway inhibition with rapamycin normalized EC hyperproliferation and pericyte coverage in postnatal retinas and stimulated VM regression in vivo. In line with the mouse data, we also report the presence of activating PIK3CA mutations in human VMs, mutually exclusive with TEK mutations. Our data demonstrate a causal relationship between activating Pik3ca mutations and the genesis of VMs, provide a genetic model that faithfully mirrors the normal etiology and development of this human disease, and establish the basis for the use of PI3K-targeted therapies in VMs.
Asunto(s)
Mutación/genética , Fosfatidilinositol 3-Quinasas/genética , Malformaciones Vasculares/enzimología , Malformaciones Vasculares/genética , Animales , Proliferación Celular/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I , Células Endoteliales/efectos de los fármacos , Células Endoteliales/patología , Humanos , Mesodermo/efectos de los fármacos , Mesodermo/embriología , Mesodermo/patología , Ratones Endogámicos C57BL , Mosaicismo/efectos de los fármacos , Pericitos/efectos de los fármacos , Pericitos/patología , Receptor TIE-2/metabolismo , Sirolimus/farmacologíaRESUMEN
In contrast to the class I phosphoinositide 3-kinases (PI3Ks), the organismal roles of the kinase activity of the class II PI3Ks are less clear. Here, we report that class II PI3K-C2ß kinase-dead mice are viable and healthy but display an unanticipated enhanced insulin sensitivity and glucose tolerance, as well as protection against high-fat-diet-induced liver steatosis. Despite having a broad tissue distribution, systemic PI3K-C2ß inhibition selectively enhances insulin signaling only in metabolic tissues. In a primary hepatocyte model, basal PI3P lipid levels are reduced by 60% upon PI3K-C2ß inhibition. This results in an expansion of the very early APPL1-positive endosomal compartment and altered insulin receptor trafficking, correlating with an amplification of insulin-induced, class I PI3K-dependent Akt signaling, without impacting MAPK activity. These data reveal PI3K-C2ß as a critical regulator of endosomal trafficking, specifically in insulin signaling, and identify PI3K-C2ß as a potential drug target for insulin sensitization.
Asunto(s)
Fosfatidilinositol 3-Quinasas Clase II/metabolismo , Insulina/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Autofagia , Glucemia/análisis , Células Cultivadas , Fosfatidilinositol 3-Quinasas Clase II/genética , Dieta Alta en Grasa , Endosomas/metabolismo , Hígado Graso/metabolismo , Hígado Graso/patología , Técnicas de Sustitución del Gen , Hepatocitos/citología , Hepatocitos/metabolismo , Insulina/sangre , Hígado/patología , Ratones , Ratones Endogámicos C57BL , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de SeñalRESUMEN
The organismal roles of the ubiquitously expressed class I PI3K isoform p110ß remain largely unknown. Using a new kinase-dead knockin mouse model that mimics constitutive pharmacological inactivation of p110ß, we document that full inactivation of p110ß leads to embryonic lethality in a substantial fraction of mice. Interestingly, the homozygous p110ß kinase-dead mice that survive into adulthood (maximum ~26% on a mixed genetic background) have no apparent phenotypes, other than subfertility in females and complete infertility in males. Systemic inhibition of p110ß results in a highly specific blockade in the maturation of spermatogonia to spermatocytes. p110ß was previously suggested to signal downstream of the c-kit tyrosine kinase receptor in germ cells to regulate their proliferation and survival. We now report that p110ß also plays a germ cell-extrinsic role in the Sertoli cells (SCs) that support the developing sperm, with p110ß inactivation dampening expression of the SC-specific Androgen Receptor (AR) target gene Rhox5, a homeobox gene critical for spermatogenesis. All extragonadal androgen-dependent functions remain unaffected by global p110ß inactivation. In line with a crucial role for p110ß in SCs, selective inactivation of p110ß in these cells results in male infertility. Our study is the first documentation of the involvement of a signalling enzyme, PI3K, in the regulation of AR activity during spermatogenesis. This developmental pathway may become active in prostate cancer where p110ß and AR have previously been reported to functionally interact.
Asunto(s)
Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Fertilidad/fisiología , Infertilidad Masculina/genética , Receptores Androgénicos/metabolismo , Células de Sertoli/metabolismo , Animales , Blastocisto/citología , Células Cultivadas , Fosfatidilinositol 3-Quinasa Clase I/antagonistas & inhibidores , Fosfatidilinositol 3-Quinasa Clase I/genética , Femenino , Proteínas de Homeodominio/genética , Infertilidad Femenina/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mórula/citología , Receptores Androgénicos/genética , Transducción de Señal/genética , Espermatogénesis/genética , Factores de Transcripción/genética , Transcripción Genética/genéticaRESUMEN
Inhibitors against the p110δ isoform of phosphoinositide-3-OH kinase (PI(3)K) have shown remarkable therapeutic efficacy in some human leukaemias. As p110δ is primarily expressed in leukocytes, drugs against p110δ have not been considered for the treatment of solid tumours. Here we report that p110δ inactivation in mice protects against a broad range of cancers, including non-haematological solid tumours. We demonstrate that p110δ inactivation in regulatory T cells unleashes CD8(+) cytotoxic T cells and induces tumour regression. Thus, p110δ inhibitors can break tumour-induced immune tolerance and should be considered for wider use in oncology.
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Inhibidores Enzimáticos/farmacología , Tolerancia Inmunológica/efectos de los fármacos , Neoplasias/enzimología , Neoplasias/inmunología , Fosfatidilinositol 3-Quinasas/metabolismo , Linfocitos T Reguladores/efectos de los fármacos , Animales , Antineoplásicos/farmacología , Activación Enzimática/efectos de los fármacos , Tolerancia Inmunológica/inmunología , Ratones , Linfocitos T Reguladores/enzimología , Linfocitos T Reguladores/inmunologíaRESUMEN
Understanding the direct, tumor cell-intrinsic effects of PI 3-kinase (PI3K) has been a key focus of research to date. Here, we report that cancer cell-extrinsic PI3K activity, mediated by the p110α isoform of PI3K, contributes in an unexpected way to tumor angiogenesis. In syngeneic mouse models, inactivation of stromal p110α led to increased vascular density, reduced vessel size, and altered pericyte coverage. This increased vascularity lacked functionality, correlating with enhanced tumor hypoxia and necrosis, and reduced tumor growth. The role of p110α in tumor angiogenesis is multifactorial, and includes regulation of proliferation and DLL4 expression in endothelial cells. p110α in the tumor stroma is thus a regulator of vessel formation, with p110α inactivation giving rise to nonfunctional angiogenesis, which can stunt tumor growth. This type of vascular aberration differs from vascular endothelial growth factor-centered antiangiogenesis therapies, which mainly lead to vascular pruning. Inhibition of p110α may thus offer a new antiangiogenic therapeutic opportunity in cancer.
Asunto(s)
Fosfatidilinositol 3-Quinasa Clase Ia/metabolismo , Neoplasias/metabolismo , Neoplasias/patología , Neovascularización Patológica/metabolismo , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Melanoma Experimental , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Neoplasias/genética , Neovascularización Patológica/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Células del Estroma/efectos de los fármacos , Células del Estroma/metabolismoRESUMEN
The insulin/insulin-like growth factor-1 signalling (IIS) pathway regulates cellular and organismal metabolism and controls the rate of aging. Gain-of-function mutations in p110α, the principal mammalian IIS-responsive isoform of PI 3-kinase (PI3K), promote cancer. In contrast, loss-of-function mutations in p110α impair insulin signalling and cause insulin resistance, inducing a pre-diabetic state. It remains unknown if long-term p110α inactivation induces further metabolic deterioration over time, leading to overt unsustainable pathology. Surprisingly, we find that chronic p110α partial inactivation in mice protects from age-related reduction in insulin sensitivity, glucose tolerance and fat accumulation, and extends the lifespan of male mice. This beneficial effect of p110α inactivation derives in part from a suppressed down-regulation of insulin receptor substrate (IRS) protein levels induced by age-related hyperinsulinemia, and correlates with enhanced insulin-induced Akt signalling in aged p110α-deficient mice. This temporal metabolic plasticity upon p110α inactivation indicates that prolonged PI3K inhibition, as intended in human cancer treatment, might not negatively impact on organismal metabolism.
Asunto(s)
Fosfatidilinositol 3-Quinasa Clase I/genética , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Enfermedades Metabólicas/enzimología , Animales , Grasas/metabolismo , Femenino , Silenciador del Gen , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Masculino , Enfermedades Metabólicas/genética , Enfermedades Metabólicas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de TiempoRESUMEN
PI3K (phosphoinositide 3-kinase) signalling pathways regulate a large array of cell biological functions in normal and cancer cells. In the present study we investigated the involvement of PI3K in modulating small molecule metabolism. A LC (liquid chromatography)-MS screen in colorectal cancer cell lines isogenic for oncogenic PIK3CA mutations revealed an association between PI3K activation and the levels of polyamine pathway metabolites, including 5-methylthioadenosine, putrescine and spermidine. Pharmacological inhibition confirmed that the PI3K pathway controls polyamine production. Despite inducing a decrease in PKB (protein kinase B)/Akt phosphorylation, spermidine promoted cell survival and opposed the anti-proliferative effects of PI3K inhibitors. Conversely, polyamine depletion by an ornithine decarboxylase inhibitor enhanced PKB/Akt phosphorylation, but suppressed cell survival. These results suggest that spermidine mediates cell proliferation and survival downstream of PI3K/Akt and indicate that these two biochemical pathways control each other's activities, highlighting a mechanism by which small molecule metabolism feeds back to regulate kinase signalling. Consistent with this feedback loop having a functional role in these cell models, pharmacological inhibitors of PI3K and ornithine decarboxylase potentiated each other in inhibiting tumour growth in a xenograft model. The results of the present study support the notion that the modulation of spermidine concentrations may be a previously unrecognized mechanism by which PI3K sustains chronic proliferation of cancer cells.
Asunto(s)
Proliferación Celular , Neoplasias/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Poliaminas/metabolismo , Animales , Cromatografía Liquida , Femenino , Humanos , Espectrometría de Masas , Metaboloma , Ratones , Ratones SCID , Trasplante de Neoplasias , Neoplasias/metabolismo , Fosfatidilinositol 3-Quinasas/fisiología , Transducción de Señal/fisiología , Trasplante Heterólogo , Células Tumorales CultivadasRESUMEN
Lipopolysaccharide activates plasma-membrane signaling and endosomal signaling by Toll-like receptor 4 (TLR4) through the TIRAP-MyD88 and TRAM-TRIF adaptor complexes, respectively, but it is unclear how the signaling switch between these cell compartments is coordinated. In dendritic cells, we found that the p110δ isoform of phosphatidylinositol-3-OH kinase (PI(3)K) induced internalization of TLR4 and dissociation of TIRAP from the plasma membrane, followed by calpain-mediated degradation of TIRAP. Accordingly, inactivation of p110δ prolonged TIRAP-mediated signaling from the plasma membrane, which augmented proinflammatory cytokine production while decreasing TRAM-dependent endosomal signaling that generated anti-inflammatory cytokines (interleukin 10 and interferon-ß). In line with that altered signaling output, p110δ-deficient mice showed enhanced endotoxin-induced death. Thus, by controlling the 'topology' of TLR4 signaling complexes, p110δ balances overall homeostasis in the TLR4 pathway.
Asunto(s)
Fosfatidilinositol 3-Quinasa Clase Ia/inmunología , Células Dendríticas/inmunología , Transducción de Señal/inmunología , Receptor Toll-Like 4/inmunología , Animales , Calpaína/farmacología , Compartimento Celular/inmunología , Membrana Celular/efectos de los fármacos , Membrana Celular/genética , Membrana Celular/inmunología , Células Cultivadas , Fosfatidilinositol 3-Quinasa Clase Ia/genética , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Endosomas/efectos de los fármacos , Endosomas/genética , Endosomas/inmunología , Expresión Génica/efectos de los fármacos , Expresión Génica/inmunología , Interferón beta/biosíntesis , Interferón beta/inmunología , Interleucina-10/biosíntesis , Interleucina-10/inmunología , Isoenzimas/genética , Isoenzimas/inmunología , Lipopolisacáridos/farmacología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Noqueados , Receptores de Interleucina/genética , Receptores de Interleucina/inmunología , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/inmunología , Choque Séptico/genética , Choque Séptico/inmunología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Receptor Toll-Like 4/genéticaRESUMEN
The PI3K (phosphoinositide 3-kinase) pathway is commonly activated in cancer as a consequence of inactivation of the tumour suppressor PTEN (phosphatase and tensin homologue deleted on chromosome 10), a major negative regulator of PI3K signalling. In line with this important role of PTEN, mice that are heterozygous for a PTEN-null allele (PTEN+/− mice) spontaneously develop a variety of tumours in multiple organs. PTEN is a phosphatase with selectivity for PtdIns(3,4,5)P3, which is produced by the class I isoforms of PI3K (p110α, p110ß, p110γ and p110δ). Previous studies indicated that PTEN-deficient cancer cell lines mainly depend on p110ß, and that p110ß, but not p110α, controls mouse prostate cancer development driven by PTEN loss. In the present study, we investigated whether the ubiquitously expressed p110α can also functionally interact with PTEN in cancer. Using genetic mouse models that mimic systemic administration of p110α- or p110ß-selective inhibitors, we confirm that inactivation of p110ß, but not p110α, inhibits prostate cancer development in PTEN+/− mice, but also find that p110α inactivation protects from glomerulonephritis, pheochromocytoma and thyroid cancer induced by PTEN loss. This indicates that p110α can modulate the impact of PTEN loss in disease and tumourigenesis. In primary and immortalized mouse fibroblast cell lines, both p110α and p110ß controlled steady-state PtdIns(3,4,5)P3 levels and Akt signalling induced by heterozygous PTEN loss. In contrast, no correlation was found in primary mouse tissues between PtdIns(3,4,5)P3 levels, PI3K/PTEN genotype and cancer development. Taken together, our results from the present study show that inactivation of either p110α or p110ß can counteract the impact of PTEN inactivation. The potential implications of these findings for PI3K-targeted therapy of cancer are discussed.