RESUMEN
Mutations in PIK3CA, the gene encoding the p110α catalytic subunit of PI3K, are among the most common mutations found in human cancer and have also recently been implicated in a range of overgrowth syndromes in humans. We have used a novel inducible "exon-switch" approach to knock in the constitutively active Pik3ca(H1047R) mutation into the endogenous Pik3ca gene of the mouse. Ubiquitous expression of the Pik3ca(H1047R) mutation throughout the body resulted in a dramatic increase in body weight within 3 weeks of induction (mutant 150 ± 5%; wild-type 117 ± 3%, mean ± sem), which was associated with increased organ size rather than adiposity. Severe metabolic effects, including a reduction in blood glucose levels to 59 ± 4% of baseline (11 days postinduction) and undetectable insulin levels, were also observed. Pik3ca(H1047R) mutant mice died earlier (median survival 46.5 d post-mutation induction) than wild-type control mice (100% survival > 250 days). Although deletion of Akt2 increased median survival by 44%, neither organ overgrowth, nor hypoglycemia were rescued, indicating that both the growth and metabolic functions of constitutive PI3K activity can be Akt2 independent. This mouse model demonstrates the critical role of PI3K in the regulation of both organ size and glucose metabolism at the whole animal level.
Asunto(s)
Hipoglucemia/enzimología , Hipoglucemia/genética , Insulina/sangre , Mutación , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Sustitución de Aminoácidos , Animales , Fosfatidilinositol 3-Quinasa Clase I , Femenino , Expresión Génica , Técnicas de Sustitución del Gen , Glucosa/metabolismo , Humanos , Hipoglucemia/metabolismo , Ratones , Ratones Noqueados , Ratones Mutantes , Ratones Transgénicos , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Tamaño de los Órganos/genética , Tamaño de los Órganos/fisiología , Proteínas Proto-Oncogénicas c-akt/deficiencia , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Aumento de PesoRESUMEN
PIK3CA, the gene encoding the p110α catalytic subunit of PI3K (phosphoinositide 3-kinase), is mutated in approximately 20% of sporadic CRCs (colorectal cancers), but the role of these mutations in the pathogenesis of CRC remains unclear. In the present study we used a novel mouse model to investigate the role of the Pik3caH1047R mutation, the most common PIK3CA mutation in CRC, during the development and progression of intestinal cancer. Our results demonstrate that Pik3caH1047R, when expressed at physiological levels, is insufficient to initiate intestinal tumorigenesis; however, in the context of Apc (adenomatous polyposis coli) loss, which is observed in 80% of CRCs and by itself results in benign intestinal adenomas, the Pik3caH1047R mutation promotes the development of highly aggressive and invasive adenocarcinomas in both the small and large intestines. The results of the present study show that an activating Pik3ca mutation can act in tandem with Apc loss to drive the progression of gastrointestinal cancer and thus this disease may be susceptible to therapeutic targeting using PI3K pathway inhibitors.
Asunto(s)
Adenocarcinoma/genética , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Regulación Neoplásica de la Expresión Génica , Neoplasias Intestinales/genética , Mutación/genética , Invasividad Neoplásica , Fosfatidilinositol 3-Quinasas/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Proteína de la Poliposis Adenomatosa del Colon/genética , Animales , Fosfatidilinositol 3-Quinasa Clase I , Progresión de la Enfermedad , Femenino , Técnicas de Sustitución del Gen , Neoplasias Intestinales/metabolismo , Neoplasias Intestinales/patología , Masculino , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Fosfatidilinositol 3-Quinasas/biosíntesisRESUMEN
Background: ZFTA-RELA (formerly known as c11orf-RELA) fused supratentorial ependymoma (ZFTAfus ST-EPN) has been recognized as a novel entity in the 2016 WHO classification of CNS tumors and further defined in the recent 2021 edition. ZFTAfus ST-EPN was reported to portend poorer prognosis when compared to its counterpart, YAP1 ST-EPN in some previously published series. The aim of this study was to determine the treatment outcome of molecularly confirmed and conventionally treated ZFTAfus ST-EPN patients treated in multiple institutions. Methods: We conducted a retrospective analysis of all pediatric patients with molecularly confirmed ZFTAfus ST-EPN patients treated in multiple institutions in 5 different countries (Australia, Canada, Germany, Switzerland, and Czechia). Survival outcomes were analyzed and correlated with clinical characteristics and treatment approaches. Results: A total of 108 patients were collated from multiple institutions in 5 different countries across three continents. We found across the entire cohort that the 5- and 10-year PFS were 65% and 63%, respectively. The 5- and 10-year OS of this cohort of patients were 87% and 73%. The rates of gross total resection (GTR) were high with 84 out of 108 (77.8%) patients achieving GTR. The vast majority of patients also received post-operative radiotherapy, 98 out of 108 (90.7%). Chemotherapy did not appear to provide any survival benefit in our patient cohort. Conclusion: This is the largest study to date of contemporaneously treated molecularly confirmed ZFTAfus ST-EPN patients which identified markedly improved survival outcomes compared to previously published series. This study also re-emphasizes the importance of maximal surgical resection in achieving optimal outcomes in pediatric patients with supratentorial ependymoma.
RESUMEN
DNA methylation array profiling for classifying pediatric central nervous system (CNS) tumors is a valuable adjunct to histopathology. However, unbiased prospective and interlaboratory validation studies have been lacking. The AIM BRAIN diagnostic trial involving 11 pediatric cancer centers in Australia and New Zealand was designed to test the feasibility of routine clinical testing and ran in parallel with the Molecular Neuropathology 2.0 (MNP2.0) study at Deutsches Krebsforschungszentrum (German Cancer Research Center). CNS tumors from 269 pediatric patients were prospectively tested on Illumina EPIC arrays, including 104 cases co-enrolled on MNP2.0. Using MNP classifier versions 11b4 and 12.5, we report classifications with a probability score ≥0.90 in 176 of 265 (66.4%) and 213 of 269 (79.2%) cases, respectively. Significant diagnostic information was obtained in 130 of 176 (74%) for 11b4, and 12 of 174 (7%) classifications were discordant with histopathology. Cases prospectively co-enrolled on MNP2.0 gave concordant classifications (99%) and score thresholds (93%), demonstrating excellent test reproducibility and sensitivity. Overall, DNA methylation profiling is a robust single workflow technique with an acceptable diagnostic yield that is considerably enhanced by the extensive subgroup and copy number profile information generated by the platform. The platform has excellent test reproducibility and sensitivity and contributes significantly to CNS tumor diagnosis.
Asunto(s)
Neoplasias del Sistema Nervioso Central , Metilación de ADN , Niño , Humanos , Australia , Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/genética , Metilación de ADN/genética , Nueva Zelanda , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
UNLABELLED: Deregulated glucose metabolism fulfills the energetic and biosynthetic requirements for tumor growth driven by oncogenes. Because inhibition of oncogenic BRAF causes profound reductions in glucose uptake and a strong clinical benefit in BRAF-mutant melanoma, we examined the role of energy metabolism in responses to BRAF inhibition. We observed pronounced and consistent decreases in glycolytic activity in BRAF-mutant melanoma cells. Moreover, we identified a network of BRAF-regulated transcription factors that control glycolysis in melanoma cells. Remarkably, this network of transcription factors, including hypoxia-inducible factor-1α, MYC, and MONDOA (MLXIP), drives glycolysis downstream of BRAF(V600), is critical for responses to BRAF inhibition, and is modulated by BRAF inhibition in clinical melanoma specimens. Furthermore, we show that concurrent inhibition of BRAF and glycolysis induces cell death in BRAF inhibitor (BRAFi)-resistant melanoma cells. Thus, we provide a proof-of-principle for treatment of melanoma with combinations of BRAFis and glycolysis inhibitors. SIGNIFICANCE: BRAF is suppress glycolysis and provide strong clinical benefi t in BRAF V600 melanoma. We show that BRAF inhibition suppresses glycolysis via a network of transcription factors that are critical for complete BRAFi responses. Furthermore, we provide evidence for the clinical potential of therapies that combine BRAFis with glycolysis inhibitors.
Asunto(s)
Glucólisis/efectos de los fármacos , Melanoma/genética , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , Línea Celular Tumoral , Resistencia a Antineoplásicos/efectos de los fármacos , Células HEK293 , Humanos , Indoles/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Melanoma/patología , Piperazinas/farmacología , Piridinas/farmacología , Sulfonamidas/farmacología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , VemurafenibRESUMEN
BACKGROUND: Ovarian cancer is the major cause of death from gynaecological malignancy with a 5year survival of only â¼30% due to resistance to platinum and paclitaxel-based first line therapy. Dysregulation of the phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) and RAS/extracellular signal-regulated kinase (ERK) pathways is common in ovarian cancer, providing potential new targets for 2nd line therapy. METHODS: We determined the inhibition of proliferation of an extensive panel of ovarian cancer cell lines, encompassing all the major histotypes, by the dual PI3K/mTOR inhibitor PF-04691502 and a MEK inhibitor, PD-0325901. In addition, we analysed global gene expression, mutation status of key PI3K/mTOR and RAS/ERK pathway members and pathway activation to identify predictors of drug response. RESULTS: PF-04691502 inhibits proliferation of the majority of cell lines with potencies that correlate with the extent of pathway inhibition. Resistant cell lines were characterised by activation of the RAS/ERK pathway as indicated by differential gene expression profiles and pathway activity analysis. PD-0325901 suppressed growth of a subset of cell lines that were characterised by high basal RAS/ERK signalling. Strikingly, using PF-04691502 and PD-0325901 in combination resulted in synergistic growth inhibition in 5/6 of PF-04691502 resistant cell lines and two cell lines resistant to both single agents showed robust synergistic growth arrest. Xenograft studies confirm the utility of combination therapy to synergistically inhibit tumour growth of PF-04691502-resistant tumours in vivo. CONCLUSIONS: These studies identify dual targeted inhibitors of PI3K/mTOR in combination with inhibitors of RAS/ERK signalling as a potentially effective new approach to treating ovarian cancer.
Asunto(s)
Benzamidas/farmacología , Proliferación Celular/efectos de los fármacos , Difenilamina/análogos & derivados , Neoplasias Ováricas/tratamiento farmacológico , Piridonas/farmacología , Pirimidinas/farmacología , Transducción de Señal/efectos de los fármacos , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Benzamidas/administración & dosificación , Línea Celular Tumoral , Difenilamina/administración & dosificación , Difenilamina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Sinergismo Farmacológico , Quinasas MAP Reguladas por Señal Extracelular/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Immunoblotting , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 1/genética , MAP Quinasa Quinasa 1/metabolismo , MAP Quinasa Quinasa 2/antagonistas & inhibidores , MAP Quinasa Quinasa 2/genética , MAP Quinasa Quinasa 2/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Piridonas/administración & dosificación , Pirimidinas/administración & dosificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/genética , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas ras/genética , Proteínas ras/metabolismoRESUMEN
UNLABELLED: MYC deregulation is common in human cancer. IG-MYC translocations that are modeled in Eµ-Myc mice occur in almost all cases of Burkitt lymphoma as well as in other B-cell lymphoproliferative disorders. Deregulated expression of MYC results in increased mTOR complex 1 (mTORC1) signaling. As tumors with mTORC1 activation are sensitive to mTORC1 inhibition, we used everolimus, a potent and specific mTORC1 inhibitor, to test the requirement for mTORC1 in the initiation and maintenance of Eµ-Myc lymphoma. Everolimus selectively cleared premalignant B cells from the bone marrow and spleen, restored a normal pattern of B-cell differentiation, and strongly protected against lymphoma development. Established Eµ-Myc lymphoma also regressed after everolimus therapy. Therapeutic response correlated with a cellular senescence phenotype and induction of p53 activity. Therefore, mTORC1-dependent evasion of senescence is critical for cellular transformation and tumor maintenance by MYC in B lymphocytes. SIGNIFICANCE: This work provides novel insights into the requirements for MYC-induced oncogenesis by showing that mTORC1 activity is necessary to bypass senescence during transformation of B lymphocytes. Furthermore, tumor eradication through senescence elicited by targeted inhibition of mTORC1 identifies a previously uncharacterized mechanism responsible for significant anticancer activity of rapamycin analogues and serves as proof-of-concept that senescence can be harnessed for therapeutic benefit
Asunto(s)
Antineoplásicos/uso terapéutico , Linfoma/tratamiento farmacológico , Proteínas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/metabolismo , Sirolimus/análogos & derivados , Animales , Linfocitos B/citología , Linfocitos B/fisiología , Diferenciación Celular/efectos de los fármacos , Senescencia Celular , Everolimus , Linfoma/metabolismo , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Ratones Transgénicos , Complejos Multiproteicos , Sirolimus/uso terapéutico , Serina-Treonina Quinasas TORRESUMEN
The phosphatidylinositol 3 kinase (PI3K) pathway is one of the major pathways modulating cell growth, proliferation, metabolism, survival, and angiogenesis. Hyperactivation of this pathway is one of the most frequent occurrences in human cancer and is thus an obvious target for treatment of this disease. Currently there are 26 novel compounds targeting the PI3K pathway being assessed in more than 150 cancer-related clinical trials. Although this pathway is involved in many vital biologic functions, data emanating from these clinical trials indicate that these drugs are well tolerated. This review outlines the interaction of the PI3K pathway with other signaling cascades, highlights mechanisms involved in hyperactivation, discusses current therapeutics in cancer-related clinical trials that target this pathway, and, based on preclinical data, discusses possible leads on patient selection and combinational therapy, including targeting multiple components of the associated signaling network.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Terapia Molecular Dirigida/métodos , Neoplasias/tratamiento farmacológico , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Animales , Retroalimentación Fisiológica/efectos de los fármacos , Retroalimentación Fisiológica/fisiología , Humanos , Modelos Biológicos , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositol 3-Quinasas/fisiología , Inhibidores de Proteínas Quinasas/administración & dosificación , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-akt/fisiología , Receptor Cross-Talk/efectos de los fármacos , Receptor Cross-Talk/fisiología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismo , Serina-Treonina Quinasas TOR/fisiologíaRESUMEN
Mutations in the gene encoding the p110α subunit of PI3K (PIK3CA) that result in enhanced PI3K activity are frequently observed in human cancers. To better understand the role of mutant PIK3CA in the initiation or progression of tumorigenesis, we generated mice in which a PIK3CA mutation commonly detected in human cancers (the H1047R mutation) could be conditionally knocked into the endogenous Pik3ca locus. Activation of this mutation in the mouse ovary revealed that alone, Pik3caH1047R induced premalignant hyperplasia of the ovarian surface epithelium but no tumors. Concomitantly, we analyzed several human ovarian cancers and found PIK3CA mutations coexistent with KRAS and/or PTEN mutations, raising the possibility that a secondary defect in a co-regulator of PI3K activity may be required for mutant PIK3CA to promote transformation. Consistent with this notion, we found that Pik3caH1047R mutation plus Pten deletion in the mouse ovary led to the development of ovarian serous adenocarcinomas and granulosa cell tumors. Both mutational events were required for early, robust Akt activation. Pharmacological inhibition of PI3K/mTOR in these mice delayed tumor growth and prolonged survival. These results demonstrate that the Pik3caH1047R mutation with loss of Pten is enough to promote ovarian cell transformation and that we have developed a model system for studying possible therapies.
Asunto(s)
Transformación Celular Neoplásica/genética , Mutación , Neoplasias Ováricas/genética , Fosfohidrolasa PTEN/deficiencia , Fosfatidilinositol 3-Quinasas/genética , Animales , Fosfatidilinositol 3-Quinasa Clase I , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neoplasias Ováricas/patología , Ovario/anatomía & histología , Ovario/patología , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Tasa de SupervivenciaRESUMEN
The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is commonly dysregulated in human cancer, making it an attractive target for novel anticancer therapeutics. We have used a mouse model of ovarian cancer generated by Kras(G12D) activation and Pten deletion in the ovarian surface epithelium for the preclinical assessment of a novel PI3K/mTOR inhibitor PF-04691502. To enable higher throughput studies, we developed an orthotopic primary transplant model from these mice and evaluated therapeutic response to PF-04691502 using small-animal ultrasound and FDG-PET imaging. PF-04691502 inhibited tumor growth at 7 days by 72% ± 9. FDG-PET imaging revealed that PF-04691502 reduced glucose metabolism dramatically, suggesting FDG-PET may be exploited as an imaging biomarker of target inhibition by PF-04691502. Tissue biomarkers of PI3K/mTOR pathway activity, p-AKT (S473), and p-RPS6 (S240/244), were also dramatically inhibited following PF-04691502 treatment. However, as a single agent, PF-04691502 did not induce tumor regression and the long-term efficacy was limited, with tumor proliferation continuing in the presence of drug treatment. We hypothesized that tumor progression was because of concomitant activation of the mitogen-activated protein kinase pathway downstream of Kras(G12D) expression promoting cell survival and that the therapeutic effect of PF-04691502 would be enhanced by combinatory inhibition of MEK using PD-0325901. This combination induced striking tumor regression, apoptosis associated with upregulation of Bim and downregulation of Mcl-1, and greatly improved duration of survival. These data suggest that contemporaneous MEK inhibition enhances the cytotoxicity associated with abrogation of PI3K/mTOR signaling, converting tumor growth inhibition to tumor regression in a mouse model of ovarian cancer driven by PTEN loss and mutant K-Ras.
Asunto(s)
Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Fosfohidrolasa PTEN/genética , Inhibidores de las Quinasa Fosfoinosítidos-3 , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Proteínas ras/genética , Animales , Metabolismo de los Hidratos de Carbono/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Femenino , Glucosa/metabolismo , Humanos , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones Transgénicos , Neoplasias Ováricas/patología , Inhibidores de Proteínas Quinasas/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Carga Tumoral/efectos de los fármacosRESUMEN
The E2F proteins are major regulators of the transcriptional program required to coordinate cell cycle progression and exit. In particular, E2f4 has been proposed to be the principal family member responsible for the regulation of cell cycle exit chiefly through its transcriptional repressive properties. We have previously shown that E2f4(-/-) mice display a marked macrocytic anemia implicating E2f4 in the regulation of erythropoiesis. However, these studies could not distinguish whether E2f4 was required for differentiation, survival, or proliferation control. Here, we describe a novel function for E2f4 in the promotion of erythroid proliferation. We show that loss of E2f4 results in an impaired expansion of the fetal erythroid compartment in vivo that is associated with impaired cell cycle progression and decreased erythroid proliferation. Consistent with these observations, cDNA microarray analysis reveals cell cycle control genes as one of the major class of genes down-regulated in E2f4(-/-) FLs, and we provide evidence that E2f4 may directly regulate the transcriptional expression of a number of these genes. We conclude that the macrocytic anemia of E2f4(-/-) mice results primarily from impaired cellular proliferation and that the major role of E2f4 in fetal erythropoiesis is to promote cell cycle progression and cellular proliferation.