RESUMO
Alterations of the tumor suppressor TP53, one of the most common events in cancer, alone are insufficient for tumor development but serve as drivers of transformation. We sought to identify cooperating events through genomic analyses of a somatic Trp53R245W mouse model (equivalent to the TP53R248W hot spot mutation in human cancers) that recapitulates metastatic breast-cancer development. We identified cooperating lesions similar to those found in human breast cancers. Moreover, we identified activation of the Pi3k/Akt/mTOR pathway in most tumors via mutations in Pten, Erbb2, Kras, and/or a recurrent Pip5k1c mutation that stabilizes the Pip5k1c protein and activates Pi3k/Akt/mTOR signaling. Another PIP5K1C family member, PIP5K1A, is coamplified with PI4KB in 18% of human breast cancer patients; both encode kinases that are responsible for production of the PI3K substrate, phosphatidylinositol 4,5-bisphosphate. Thus, the TP53R248W mutation and PI3K/AKT/mTOR signaling are major cooperative events driving breast-cancer development. Additionally, a combination of two US Food and Drug Administration (FDA)-approved drugs, tigecycline and metformin, which target oxidative phosphorylation downstream of PI3K signaling, inhibited tumor cell growth and may be repurposed for breast-cancer treatment. These findings advance our understanding of how mutant p53 drives breast-tumor development and pinpoint the importance of PI3K/AKT/mTOR signaling, expanding combination therapies for breast-cancer treatment.
Assuntos
Neoplasias da Mama , Fosfatidilinositol 3-Quinases , Animais , Feminino , Humanos , Camundongos , Neoplasias da Mama/patologia , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
TP53 is the most frequently mutated gene in human cancer. Many mutant p53 proteins exert oncogenic gain-of-function (GOF) properties that contribute to metastasis, but the mechanisms mediating these functions remain poorly defined in vivo. To elucidate how mutant p53 GOF drives metastasis, we developed a traceable somatic osteosarcoma mouse model that is initiated with either a single p53 mutation (p53R172H) or p53 loss in osteoblasts. Our study confirmed that p53 mutant mice developed osteosarcomas with increased metastasis as compared with p53-null mice. Comprehensive transcriptome RNA sequencing (RNA-seq) analysis of 16 tumors identified a cluster of small nucleolar RNAs (snoRNAs) that are highly up-regulated in p53 mutant tumors. Regulatory element analysis of these deregulated snoRNA genes identified strong enrichment of a common Ets2 transcription factor-binding site. Homozygous deletion of Ets2 in p53 mutant mice resulted in strong down-regulation of snoRNAs and reversed the prometastatic phenotype of mutant p53 but had no effect on osteosarcoma development, which remained 100% penetrant. In summary, our studies identify Ets2 inhibition as a potential therapeutic vulnerability in p53 mutant osteosarcomas.
Assuntos
Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Regulação Neoplásica da Expressão Gênica , Osteossarcoma/genética , Osteossarcoma/secundário , Proteína Proto-Oncogênica c-ets-2/genética , RNA Nucleolar Pequeno/genética , Proteína Supressora de Tumor p53/genética , Animais , Regulação para Baixo , Perfilação da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Camundongos , Camundongos Knockout , Mutação , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Osteoblastos/metabolismo , Osteoblastos/patologia , Regulação para CimaRESUMO
Gastrointestinal (GI) syndrome is a serious side effect and dose-limiting toxicity observed in patients undergoing lower-abdominal radiotherapy. Previous mouse studies show that p53 gene dosage determines susceptibility to GI syndrome development. However, the translational relevance of p53 activity has not been addressed. Here, we used a knock-in mouse in which the p53-Mdm2 negative feedback loop is genetically disrupted. These mice retain biallelic p53 and thus, normal basal p53 levels and activity. However, due to the lack of p53-mediated Mdm2 transcription, irradiated Mdm2P2/P2 mice exhibit enhanced acute p53 activity, which protects them from GI failure. Intestinal crypt cells residing in the +4 and higher positions exhibit decreased apoptosis, increased p21 expression, and hyperproliferation to reinstate intestinal integrity. Correspondingly, pharmacological augmentation of p53 activity in wild-type mice with an Mdm2 inhibitor protects against GI toxicity without affecting therapeutic outcome. Our results suggest that transient disruption of the p53-Mdm2 interaction to enhance p53 activity could be a viable prophylactic strategy for alleviating GI syndrome in patients undergoing radiotherapy.
Assuntos
Gastroenteropatias/etiologia , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/efeitos da radiação , Lesões por Radiação/metabolismo , Radiação Ionizante , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Gastroenteropatias/metabolismo , Gastroenteropatias/mortalidade , Gastroenteropatias/patologia , Trato Gastrointestinal/patologia , Humanos , Camundongos , Camundongos Knockout , Modelos Biológicos , Lesões por Radiação/genética , Lesões por Radiação/mortalidade , Lesões por Radiação/patologia , Lesões Experimentais por Radiação , Proteína Supressora de Tumor p53/genética , Proteínas ras/genética , Proteínas ras/metabolismoRESUMO
The p53-Mdm2 feedback loop is perceived to be critical for regulating stress-induced p53 activity and levels. However, this has never been tested in vivo. Using a genetically engineered mouse with mutated p53 response elements in the Mdm2 P2 promoter, we show that feedback loop-deficient Mdm2(P2/P2) mice are viable and aphenotypic and age normally. p53 degradation kinetics after DNA damage in radiosensitive tissues remains similar to wild-type controls. Nonetheless, DNA damage response is elevated in Mdm2(P2/P2) mice. Enhanced p53-dependent apoptosis sensitizes hematopoietic stem cells (HSCs), causing drastic myeloablation and lethality. These results suggest that while basal Mdm2 levels are sufficient to regulate p53 in most tissues under homeostatic conditions, the p53-Mdm2 feedback loop is critical for regulating p53 activity and sustaining HSC function after DNA damage. Therefore, transient disruption of p53-Mdm2 interaction could be explored as a potential adjuvant/therapeutic strategy for targeting stem cells in hematological malignancies.
Assuntos
Dano ao DNA/genética , Retroalimentação Fisiológica , Longevidade/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/genética , Dano ao DNA/efeitos da radiação , Técnicas de Introdução de Genes , Células-Tronco Hematopoéticas/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Mutação/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica/genética , Desnaturação Proteica/efeitos da radiação , Estabilidade Proteica/efeitos da radiação , Tolerância a Radiação/genética , Radiação Ionizante , Raios UltravioletaRESUMO
BACKGROUND: The purpose of the present study was to characterize the prevalence, associated factors, and to construct a nomogram for predicting bone metastasis (BM) with different histological types of lung cancer. PATIENTS AND METHODS: This study was a descriptive study that basing on the invasive lung cancer patients diagnosed between 2010 and 2014 in Surveillance, Epidemiology, and End Results program. A total of 125,652 adult patients were retrieved. Logistic regression analysis was conducted to investigate homogeneous and heterogeneous factors for BM occurrence. Nomogram was constructed to predict the risk for developing BM and the performance was evaluated by the receiver operating characteristics curve (ROC) and the calibration curve. The overall survival of the patients with BM was analyzed using the Kaplan-Meier method and the survival differences were tested by the log-rank test. RESULTS: A total of 25,645 (20.9%) were reported to have BM, and the prevalence in adenocarcinoma, squamous cell carcinoma, small cell lung cancer (SCLC), large cell lung cancer (LCLC), and non-small cell lung cancer/not otherwise specified lung cancer (NSCLC/NOS) were 24.4, 12.5, 24.7, 19.5 and 19.4%, respectively, with significant difference (P < 0.001). Male gender, more metastatic sites and lymphatic metastasis were positively associated with BM in all lung cancer subtypes. Larger tumor size was positively associated with BM in all the lung cancer subtypes except for NSCLC/NOS. Poorly differentiated histology was positively associated with adenocarcinoma, squamous cell carcinoma and NSCLC/NOS. The calibration curve and ROC curve exhibited good performance for predicting BM. The median survival of the bone metastatic lung cancer patients was 4.00 (95%CI: 3.89-4.11) months. With the increased number of the other metastatic sites (brain, lung and liver metastasis), the survival significantly decreased (p < 0.001). CONCLUSION: Different lung cancer histological subtypes exhibited distinct prevalence and homogeneity and heterogeneity associated factors for BM. The nomogram has good calibration and discrimination for predicting BM of lung cancer.
Assuntos
Neoplasias Ósseas/epidemiologia , Neoplasias Ósseas/secundário , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/patologia , Nomogramas , Adulto , Idoso , Carcinoma de Células Grandes/epidemiologia , Carcinoma de Células Grandes/patologia , Carcinoma Pulmonar de Células não Pequenas/epidemiologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Modelos Logísticos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Programa de SEER , Fatores Sexuais , Carcinoma de Pequenas Células do Pulmão/epidemiologia , Carcinoma de Pequenas Células do Pulmão/patologia , Análise de Sobrevida , Carga Tumoral , Estados Unidos/epidemiologiaRESUMO
BACKGROUND The objective of the present research was to explore the prevalence, risk, and prognostic factors associated with bone metastases (BM) in newly diagnosed hepatocellular carcinoma (HCC) patients. MATERIAL AND METHODS From 36 507 HCC patients who were registered in Surveillance, Epidemiology, and End Results (SEER) database, we enrolled 1263 with BM at the initial diagnosis of HCC from 2010 to 2014. Kaplan-Meier curves and log-rank tests were used to estimate overall survival for different subgroups. Univariate and multivariate logistic and Cox regression analyses were performed to identify risk factors and independent prognostic factors for BM. RESULTS A total of 1567 (4.29%) HCC patients were detected with BM at initial diagnosis. Male sex, unmarried status, higher T stage, lymph node involvement, intrahepatic metastases, and extrahepatic metastases (lung or brain) were positively associated with BM. The median survival of the patients was 3.00 months (95% CI: 2.77-3.24 months). Marital status and primary tumor surgery were independently associated with the better survival. CONCLUSIONS A list of factors associated with BM occurrence and the prognosis of the advanced HCC patients with BM were found. These associated factors may provide a reference for BM screening in HCC and guide prophylactic treatment in clinical settings.
Assuntos
Neoplasias Ósseas/mortalidade , Carcinoma Hepatocelular/mortalidade , Metástase Neoplásica/fisiopatologia , Adulto , Idoso , Biomarcadores Tumorais , Neoplasias Ósseas/fisiopatologia , Osso e Ossos/fisiopatologia , Carcinoma Hepatocelular/fisiopatologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Prevalência , Prognóstico , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Programa de SEERRESUMO
BACKGROUND/AIMS: Gain-of-function of mutant p53 is associated with a high rate of lung metastasis in osteosarcoma. To investigate the mechanism of mutant p53-induced osteosarcoma metastasis, expression array analysis was performed, comparing non-metastatic osteosarcomas from p53+/- mice with metastatic osteosarcomas from p53R172H/+ mice. Onzin (Plac8) was identified as one of the genes upregulated in p53R172H/+ mouse metastatic osteosarcomas. Accordingly, we investigated the role of ONZIN in human osteosarcoma metastasis. METHODS: ONZIN function and its downstream targets were examined in osteosarcoma cell lines. Assays related to tumorigenesis and metastasis, including cell migration, invasion, clonogenic survival, and soft agar colony formation, were performed in osteosarcoma cells. Additionally, mouse xenograft models were used to examine the role of ONZIN overpression in tumorigenesis in vivo. Lastly, 87 osteosarcoma patients were recruited to investigate the clinical relevance of ONZIN overexpression in metastasis and prognosis. RESULTS: ONZIN overexpression enhanced osteosarcoma cell proliferation, clonogenic survival, migration, and invasion independent of p53 status. Furthermore, ONZIN overexpression induced CXCL5 upregulation and resulted in increased ERK phosphorylation, which contributed to more aggressive osteosarcoma metastatic phenotypes. More importantly, overexpression of ONZIN in human osteosarcoma patients was closely associated with lung metastasis, poor prognoses, and survival. CONCLUSIONS: Overexpression of ONZIN promotes osteosarcoma progression and metastasis, and can serve as a clinical biomarker for osteosarcoma metastasis and prognosis.
Assuntos
Quimiocina CXCL5/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Adulto , Animais , Carcinogênese , Linhagem Celular Tumoral , Proliferação de Células , Quimiocina CXCL5/antagonistas & inibidores , Quimiocina CXCL5/genética , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Proteínas/antagonistas & inibidores , Proteínas/genética , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Transplante Heterólogo , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/genéticaRESUMO
The p53 inhibitor Mdm4 is present at high levels in multiple human cancers. Overexpression of Mdm4 in mice drives the spontaneous development of mostly lymphomas and sarcomas. In this study, we explored the ability of Mdm4 to cooperate with lesions in tumour development. The Mdm4 transgene contributed to mammary tumour development in a BALB/cJ background. High levels of Mdm4 enhanced tumour development in a mutant p53R172H heterozygous background, and reduced the need to lose the wild-type p53 allele, as compared with mice heterozygous only for the p53R172H mutation. Additionally, high levels of Mdm4 cooperated with an oncogenic K-ras mutation to drive lung tumourigenesis in vivo. Finally, we examined p53-independent functions of Mdm4 by studying the contribution of Mdm4 to tumour development in the absence of p53. Whereas the overall survival times of p53-null mice with and without the Mdm4 transgene were similar, male mice with both alterations showed significantly shorter survival than p53-null male mice, and showed differences in tumour spectrum, demonstrating a p53-independent function of Mdm4 in tumourigenesis. Furthermore, p53-null mice with the highest level of Mdm4 tended to have multiple tumours. Thus, a detailed analysis of Mdm4 transgenic mice in various genetic backgrounds shows synergy in tumour development in vivo. Mdm4 may thus serve as a therapeutic target in cancers. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Assuntos
Carcinogênese/genética , Linfoma/genética , Proteínas Proto-Oncogênicas/genética , Sarcoma/genética , Proteína Supressora de Tumor p53/genética , Animais , Regulação Neoplásica da Expressão Gênica , Humanos , Perda de Heterozigosidade , Linfoma/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Mutação , Proteínas Proto-Oncogênicas/metabolismo , Sarcoma/patologia , Transgenes , Proteína Supressora de Tumor p53/metabolismoRESUMO
5-Fluorouracil (5-FU) is one of the most commonly used chemotherapeutic agents in colon cancer treatment, but has a narrow therapeutic index limited by its toxicity. Melatonin exerts antitumor activity in various cancers, but it has never been combined with 5-FU as an anticolon cancer treatment to improve the chemotherapeutic effect of 5-FU. In this study, we assessed such combinational use in colon cancer and investigated whether melatonin could synergize the antitumor effect of 5-FU. We found that melatonin significantly enhanced the 5-FU-mediated inhibition of cell proliferation, colony formation, cell migration and invasion in colon cancer cells. We also found that melatonin synergized with 5-FU to promote the activation of the caspase/PARP-dependent apoptosis pathway and induce cell cycle arrest. Further mechanism study demonstrated that melatonin synergized the antitumor effect of 5-FU by targeting the PI3K/AKT and NF-κB/inducible nitric oxide synthase (iNOS) signaling. Melatonin in combination with 5-FU markedly suppressed the phosphorylation of PI3K, AKT, IKKα, IκBα, and p65 proteins, promoted the translocation of NF-κB p50/p65 from the nuclei to cytoplasm, abrogated their binding to the iNOS promoter, and thereby enhanced the inhibition of iNOS signaling. In addition, pretreatment with a PI3K- or iNOS-specific inhibitor synergized the antitumor effects of 5-FU and melatonin. Finally, we verified in a xenograft mouse model that melatonin and 5-FU exerted synergistic antitumor effect by inhibiting the AKT and iNOS signaling pathways. Collectively, our study demonstrated that melatonin synergized the chemotherapeutic effect of 5-FU in colon cancer through simultaneous suppression of multiple signaling pathways.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias do Colo/patologia , Fluoruracila/farmacologia , Melatonina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Imunoprecipitação da Cromatina , Sinergismo Farmacológico , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Nus , Microscopia Confocal , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
p53(R172H/+) mice inherit a p53 mutation found in Li-Fraumeni syndrome and develop metastatic tumors at much higher frequency than p53(+/-) mice. To explore the mutant p53 metastatic phenotype, we used expression arrays to compare primary osteosarcomas from p53(R172H/+) mice with metastasis to osteosarcomas from p53(+/-) mice lacking metastasis. For this study, 213 genes were differentially expressed with a P value <0.05. Of particular interest, Pla2g16, which encodes a phospholipase that catalyzes phosphatidic acid into lysophosphatidic acid and free fatty acid (both implicated in metastasis), was increased in p53(R172H/+) osteosarcomas. Functional analyses showed that Pla2g16 knockdown decreased migration and invasion in mutant p53-expressing cells, and vice versa: overexpression of Pla2g16 increased the invasion of p53-null cells. Furthermore, Pla2g16 levels were increased upon expression of mutant p53 in both mouse and human osteosarcoma cell lines, indicating that Pla2g16 is a downstream target of the mutant p53 protein. ChIP analysis revealed that several mutant p53 proteins bind the Pla2g16 promoter at E26 transformation-specific (ETS) binding motifs and knockdown of ETS2 suppressed mutant p53 induction of Pla2g16. Thus, our study identifies a phospholipase as a transcriptional target of mutant p53 that is required for metastasis.
Assuntos
Neoplasias Ósseas/metabolismo , Síndrome de Li-Fraumeni/metabolismo , Mutação , Osteossarcoma/metabolismo , Fosfolipases A2 Independentes de Cálcio/biossíntese , Proteínas Supressoras de Tumor/biossíntese , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Humanos , Síndrome de Li-Fraumeni/genética , Síndrome de Li-Fraumeni/patologia , Camundongos , Camundongos Mutantes , Invasividade Neoplásica , Osteossarcoma/genética , Osteossarcoma/patologia , Fosfolipases A2 Independentes de Cálcio/genética , Elementos de Resposta , Proteínas Supressoras de Tumor/genéticaRESUMO
Osteosarcoma is a highly aggressive bone disease with a tendency to metastasize to the lung. The 5-year survival of patients with metastatic osteosarcoma is only 20 %. Many studies have demonstrated SDF-1/CXCR4 and MMP9 play important roles in the metastasis of malignant tumors, including osteosarcoma. The aim of this study was to investigate the association of CXCR4 and MMP9 expression with clinicopathological features and pulmonary metastasis in osteosarcoma. Using tumor tissue microarrays, we analyzed the expression of CXCR4 and MMP9 among 34 primary osteosarcomas with pulmonary metastasis and 62 primary osteosarcomas without metastasis. A median time of 57.5 months (range: 6 to 171 months) follow-up was performed to evaluate tumor metastasis and the patient survival. The prognostic values were determined by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. The accuracy of oncologic outcome prediction was evaluated by receiver-operating characteristics (ROC) curves (AUC). The expression of CXCR4 and MMP9 was significantly correlated in tumor tissues (P = 0.026). Both CXCR4 and MMP9 were independent predictors for overall survival and metastasis-free survival by Cox multivariate analysis, and high expression for both CXCR4 and MMP9 were even more significant and better biomarkers for osteosarcoma metastasis and survival. The combination of CXCR4 and MMP9 high expression is very likely to be a valuable independent predictor of lung metastasis and survival in osteosarcoma patients.
Assuntos
Biomarcadores Tumorais/biossíntese , Neoplasias Pulmonares/cirurgia , Metaloproteinase 9 da Matriz/biossíntese , Osteossarcoma/cirurgia , Receptores CXCR4/biossíntese , Adulto , Biomarcadores Tumorais/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Masculino , Metaloproteinase 9 da Matriz/genética , Pessoa de Meia-Idade , Osteossarcoma/genética , Osteossarcoma/patologia , Prognóstico , Modelos de Riscos Proporcionais , Receptores CXCR4/genética , Análise Serial de TecidosRESUMO
Mdm2, an E3 ubiquitin ligase, negatively regulates the tumour suppressor p53. In this study we utilized a conditional Mdm2 allele, Mdm2(FM) , and a CAG-CreER tamoxifen-inducible recombination system to examine the effects of global Mdm2 loss in adult mice. Two different tamoxifen injection regimens caused 100% lethality of Mdm2(FM) (/-) ;CAG-CreER mice; both radio-sensitive and radio-insensitive tissues were impaired. Strikingly, a large number of radio-insensitive tissues, including the kidney, liver, heart, retina and hippocampus, exhibited various pathological defects. Similar tamoxifen injections in older (16-18 month-old) Mdm2(FM) (/-) ;CAG-CreER mice yielded abnormalities only in the kidney. In addition, transcriptional activation of Cdkn1a (p21), Bbc3 (Puma) and multiple senescence markers in young (2-4 month-old) mice following loss of Mdm2 was dampened in older mice. All phenotypes were p53-dependent, as Mdm2(FM) (/-) ;Trp53(-/-) ;CAG-CreER mice subjected to the same tamoxifen regimens were normal. Our findings implicate numerous possible toxicities in many normal tissues upon use of cancer therapies that aim to inhibit Mdm2 in tumours with wild-type p53.
Assuntos
Envelhecimento/patologia , Rim/patologia , Fígado/patologia , Miocárdio/patologia , Proteínas Proto-Oncogênicas c-mdm2/deficiência , Proteínas Proto-Oncogênicas c-mdm2/fisiologia , Proteína Supressora de Tumor p53/fisiologia , Envelhecimento/efeitos dos fármacos , Alelos , Animais , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Injeções , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Camundongos , Camundongos Knockout , Modelos Animais , Fenótipo , Proteínas Proto-Oncogênicas c-mdm2/genética , Retina/efeitos dos fármacos , Retina/patologia , Tamoxifeno/administração & dosagem , Tamoxifeno/farmacologiaRESUMO
Deregulation of cell polarity proteins has been linked to the processes of invasion and metastasis. TRIM62 is a regulator of cell polarity and a tumour suppressor in breast cancer. Here, we demonstrate that human non-small cell lung cancer lesions show a step-wise loss of TRIM62 levels during disease progression, which was associated with poor clinical outcomes. To directly examine the role of Trim62 in development of lung cancer, we deleted Trim62 in a mutant K-Ras mouse model of lung cancer. In this context, haploinsufficiency of Trim62 synergized with a K-RasG12D mutation to promote invasiveness and disrupt three-dimensional morphogenesis, both of which are associated with epithelial-mesenchymal transitions. Re-expression of Trim62 reverted these phenotypes in tumour cell lines. Thus, Trim62 loss cooperates with K-Ras mutation in tumourigenesis and metastasis in vivo, indicating that decreased levels of TRIM62 may play an important role in the evolution of lung cancer.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Regulação Neoplásica da Expressão Gênica , Genes ras/genética , Neoplasias Pulmonares/genética , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Animais , Carcinoma Pulmonar de Células não Pequenas/patologia , Transformação Celular Neoplásica , Transição Epitelial-Mesenquimal , Feminino , Humanos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mutação , Receptores de Angiotensina/genética , Receptores de Angiotensina/metabolismo , Receptores de Endotelina/genética , Receptores de Endotelina/metabolismo , Proteínas com Motivo Tripartido , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Mdm2 and Mdm4 are homologous RING domain-containing proteins that negatively regulate the tumor suppressor p53 under physiological and stress conditions. The RING domain of Mdm2 encodes an E3-ubiquitin ligase that promotes p53 degradation. In addition, Mdm2 and Mdm4 interact through their respective RING domains. The in vivo significance of Mdm2-Mdm4 heterodimerization in regulation of p53 function is unknown. In this study, we generated an Mdm4 conditional allele lacking the RING domain to investigate its role in Mdm2 and p53 regulation. Our results demonstrate that homozygous deletion of the Mdm4 RING domain results in prenatal lethality. Mechanistically, Mdm2-Mdm4 heterodimerization is critical for inhibiting lethal p53 activation during early embryogenesis. However, Mdm2-Mdm4 interaction is dispensable for regulating p53 activity as well as the stability of Mdm2 and p53 at later stages of development. We propose that Mdm4 is a key cofactor of Mdm2 that inhibits p53 activity primarily during early embryogenesis but is dispensable for regulating p53 and Mdm2 stability in the adult mouse.
Assuntos
Desenvolvimento Embrionário/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/genética , Multimerização Proteica/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Southern Blotting , Radioisótopos de Césio , Primers do DNA/genética , Desenvolvimento Embrionário/genética , Genótipo , Camundongos , Camundongos Transgênicos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ubiquitina-Proteína Ligases/genética , UbiquitinaçãoRESUMO
The TP53 tumor suppressor gene is mutated early in most of the patients with triple-negative breast cancer (TNBC). The most frequent TP53 alterations are missense mutations that contribute to tumor aggressiveness. Here, we used an autochthonous somatic TNBC mouse model, in which mutant p53 can be toggled on and off genetically while leaving the tumor microenvironment intact and wild-type for p53 to identify physiological dependencies on mutant p53. In TNBCs that develop in this model, deletion of two different hotspot p53R172H and p53R245W mutants triggers ferroptosis in vivo, a cell death mechanism involving iron-dependent lipid peroxidation. Mutant p53 protects cells from ferroptosis inducers, and ferroptosis inhibitors reverse the effects of mutant p53 loss in vivo. Single-cell transcriptomic data revealed that mutant p53 protects cells from undergoing ferroptosis through NRF2-dependent regulation of Mgst3 and Prdx6, which encode two glutathione-dependent peroxidases that detoxify lipid peroxides. Thus, mutant p53 protects TNBCs from ferroptotic death.
Assuntos
Adenocarcinoma , Ferroptose , Neoplasias de Mama Triplo Negativas , Animais , Humanos , Camundongos , Linhagem Celular Tumoral , Ferroptose/genética , Neoplasias de Mama Triplo Negativas/patologia , Microambiente Tumoral , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Aggressive breast cancers harbor TP53 missense mutations. Tumor cells with TP53 missense mutations exhibit enhanced growth and survival through transcriptional rewiring. To delineate how TP53 mutations in breast cancer contribute to tumorigenesis and progression in vivo, we created a somatic mouse model driven by mammary epithelial cell-specific expression of Trp53 mutations. Mice developed primary mammary tumors reflecting the human molecular subtypes of luminal A, luminal B, HER2-enriched, and triple-negative breast cancer with metastases. Transcriptomic analyses comparing MaPR172H/- or MaPR245W/- mammary tumors to MaP-/- tumors revealed (1) differences in cancer-associated pathways activated in both p53 mutants and (2) Nr5a2 as a novel transcriptional mediator of distinct pathways in p53 mutants. Meta-analyses of human breast tumors corroborated these results. In vitro assays demonstrate mutant p53 upregulates specific target genes that are enriched for Nr5a2 response elements in their promoters. Co-immunoprecipitation studies revealed p53R172H and p53R245W interact with Nr5a2. These findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer. SIGNIFICANCE: Our findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer. NR5A2 may be an important therapeutic target in hard-to-treat breast cancers such as endocrine-resistant tumors and metastatic triple-negative breast cancers harboring TP53 missense mutations.
Assuntos
Neoplasias Mamárias Experimentais , Transcriptoma , Proteína Supressora de Tumor p53 , Animais , Feminino , Humanos , Camundongos , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/patologia , Neoplasias Mamárias Animais/metabolismo , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/metabolismo , Mutação , Mutação de Sentido Incorreto , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53. Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models. The tissue-specific deletion of Mdm2 induces p53-dependent apoptosis, whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest. Compared to Mdm4 deletion, Mdm2 deletion causes more severe phenotypic defects. Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53, suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis. Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis, which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes. Studies from these mouse models strongly suggest that blocking Mdm2- and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.
Assuntos
Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Apoptose , Pontos de Checagem do Ciclo Celular , Camundongos , Camundongos Knockout , Modelos Animais , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/genética , Ubiquitina-Proteína Ligases/genéticaRESUMO
Whether p53, either wild type (WT) or mutant, plays cell-specific or uniform role remains controversial. Using The Cancer Genome Atlas, we examined p53 in the lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), two lung cancers with different cellular origins and frequent p53 mutation (52% and 83%, respectively). Mutant p53 more strongly correlates with different genomic alteration and protein expression profiles in LUAD than in LUSC. p53 mutation in LUAD and LUSC is associated with multiple exacerbated clinical outcomes. Although the presence of p53 mutation does not change the survival of LUAD patients, LUSC patients containing p53 mutation exhibit surprisingly prolonged survivals. Ingenuity Pathway Analyses with genes co-expressed with WT or mutant p53 in both LUAD and LUSC show that mutant p53 in these two cancers are correlated with different signaling. Additionally, WT p53 in LUAD are largely associated with activation of tumor suppressive pathways and suppression of the tumor promotive ones, a pattern different from what is observed for WT p53 in LUSC. Furthermore, pathway analyses of genes differentially expressed between cancers with mutant and WT p53 for both LUAD and LUSC revealed different pathway fashions for these two cancers. Our study indicates that both WT and mutant p53 may have cell-specific functions, which needs to be validated with future experimental investigations.
RESUMO
Cancer-related alterations of the p53 tetramerization domain (TD) abrogate wild-type (WT) p53 function. They result in a protein that preferentially forms monomers or dimers, which are also normal p53 states under basal cellular conditions. However, their physiologic relevance is not well understood. We have established in vivo models for monomeric and dimeric p53, which model Li-Fraumeni syndrome patients with germline p53 TD alterations. p53 monomers are inactive forms of the protein. Unexpectedly, p53 dimers conferred some tumor suppression that is not mediated by canonical WT p53 activities. p53 dimers upregulate the PPAR pathway. These activities are associated with lower prevalence of thymic lymphomas and increased CD8+ T-cell differentiation. Lymphomas derived from dimeric p53 mice show cooperating alterations in the PPAR pathway, further implicating a role for these activities in tumor suppression. Our data reveal novel functions for p53 dimers and support the exploration of PPAR agonists as therapies. SIGNIFICANCE: New mouse models with TP53R342P (monomer) or TP53A347D (dimer) mutations mimic Li-Fraumeni syndrome. Although p53 monomers lack function, p53 dimers conferred noncanonical tumor-suppressive activities. We describe novel activities for p53 dimers facilitated by PPARs and propose these are "basal" p53 activities. See related commentary by Stieg et al., p. 1046. See related article by Choe et al., p. 1250. This article is highlighted in the In This Issue feature, p. 1027.
Assuntos
Síndrome de Li-Fraumeni , Animais , Camundongos , Síndrome de Li-Fraumeni/genética , Síndrome de Li-Fraumeni/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ativação Transcricional , Receptores Ativados por Proliferador de Peroxissomo/genética , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Morte CelularRESUMO
Murine double minute 2 (Mdm2) is the principal E3-ubiquitin ligase for p53 and contains a C2H2C4 type RING domain wherein the last cysteine residue is followed by an evolutionarily conserved 13 amino acid C-terminal tail. Previous studies have indicated that integrity of the C-terminal tail is critical for Mdm2 function. Recently, a mutation extending the MDM2 length by five amino acids was identified and associated with enhanced p53 response in fibroblasts and premature aging in a human patient. To investigate the importance of the conserved Mdm2 C-terminal length on p53 regulatory function in vivo, we engineered three novel mouse alleles using CRISPR-Cas9 technology. Genetic studies with these murine models showed that curtailing Mdm2 C-terminal length by even a single amino acid leads to p53-dependent embryonic lethality. Extension of the Mdm2 C-terminal length by five amino acids (QLTCL) yielded viable mice that are smaller in size, exhibit fertility problems, and have a shortened life span. Analysis of early passage mouse embryonic fibroblasts indicated impaired Mdm2 function correlates with enhanced p53 activity under stress conditions. Furthermore, analysis in mice showed tissue-specific alterations in p53 target gene expression and enhanced radiosensitivity. These results confirm the physiological importance of the evolutionarily conserved Mdm2 C-terminus in regulating p53 functions. SIGNIFICANCE: This in vivo study highlights that alterations to the C-terminus of Mdm2 perturb its regulation of the tumor suppressor p53.