RÉSUMÉ
The majority of EGFR mutant lung adenocarcinomas respond well to EGFR tyrosine kinase inhibitors (TKI). However, most of these responses are partial, with drug-tolerant residual disease remaining even at the time of maximal response. This residual disease can ultimately lead to relapses, which eventually develop in most patients. To investigate the cellular and molecular properties of residual tumor cells in vivo, we leveraged patient-derived xenograft (PDX) models of EGFR mutant lung cancer. Subcutaneous EGFR mutant PDXs were treated with the third-generation TKI osimertinib until maximal tumor regression. Residual tissue inevitably harbored tumor cells that were transcriptionally distinct from bulk pretreatment tumor. Single-cell transcriptional profiling provided evidence of cells matching the profiles of drug-tolerant cells present in the pretreatment tumor. In one of the PDXs analyzed, osimertinib treatment caused dramatic transcriptomic changes that featured upregulation of the neuroendocrine lineage transcription factor ASCL1. Mechanistically, ASCL1 conferred drug tolerance by initiating an epithelial-to-mesenchymal gene-expression program in permissive cellular contexts. This study reveals fundamental insights into the biology of drug tolerance, the plasticity of cells through TKI treatment, and why specific phenotypes are observed only in certain tumors. SIGNIFICANCE: Analysis of residual disease following tyrosine kinase inhibitor treatment identified heterogeneous and context-specific mechanisms of drug tolerance in lung cancer that could lead to the development of strategies to forestall drug resistance. See related commentary by Rumde and Burns, p. 1188.
Sujet(s)
Acrylamides , Carcinome pulmonaire non à petites cellules , Indoles , Tumeurs du poumon , Pyrimidines , Humains , Tumeurs du poumon/traitement médicamenteux , Tumeurs du poumon/génétique , Tumeurs du poumon/anatomopathologie , Carcinome pulmonaire non à petites cellules/traitement médicamenteux , Carcinome pulmonaire non à petites cellules/génétique , Carcinome pulmonaire non à petites cellules/anatomopathologie , Récepteurs ErbB/génétique , Résistance aux médicaments antinéoplasiques/génétique , Récidive tumorale locale/traitement médicamenteux , Dérivés de l'aniline/pharmacologie , Dérivés de l'aniline/usage thérapeutique , Inhibiteurs de protéines kinases/pharmacologie , Inhibiteurs de protéines kinases/usage thérapeutique , Mutation , Facteurs de transcription à motif basique hélice-boucle-hélice/génétiqueRÉSUMÉ
Metastatic breast cancer remains a major cause of cancer-related deaths in women, and there are few effective therapies against this advanced disease. Emerging evidence suggests that key steps of tumor progression and metastasis are controlled by reversible epigenetic mechanisms. Using an in vivo genetic screen, we identified WDR5 as an actionable epigenetic regulator that is required for metastatic progression in models of triple-negative breast cancer. We found that knockdown of WDR5 in breast cancer cells independently impaired their tumorigenic as well as metastatic capabilities. Mechanistically, WDR5 promotes cell growth by increasing ribosomal gene expression and translation efficiency in a KMT2-independent manner. Consistently, pharmacological inhibition or degradation of WDR5 impedes cellular translation rate and the clonogenic ability of breast cancer cells. Furthermore, a combination of WDR5 targeting with mTOR inhibitors leads to potent suppression of translation and proliferation of breast cancer cells. These results reveal novel therapeutic strategies to treat metastatic breast cancer.
Sujet(s)
Tumeurs du sein , Humains , Femelle , Tumeurs du sein/génétique , Tumeurs du sein/anatomopathologie , Histone-lysine N-methyltransferase/métabolisme , Lignée cellulaire tumorale , Protéines et peptides de signalisation intracellulaire/génétique , Prolifération cellulaireRÉSUMÉ
Metastasis is the major cause of cancer-related deaths due to the lack of effective therapies. Emerging evidence suggests that certain epigenetic and transcriptional regulators drive cancer metastasis and could be targeted for metastasis treatment. To identify epigenetic regulators of breast cancer metastasis, we profiled the transcriptomes of matched pairs of primary breast tumors and metastases from human patients. We found that distant metastases are more immune inert with increased M2 macrophages compared to their matched primary tumors. The acetyl-lysine reader, cat eye syndrome chromosome region candidate 2 (CECR2), was the top up-regulated epigenetic regulator in metastases associated with an increased abundance of M2 macrophages and worse metastasis-free survival. CECR2 was required for breast cancer metastasis in multiple mouse models, with more profound effect in the immunocompetent setting. Mechanistically, the nuclear factor κB (NF-κB) family member v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA) recruits CECR2 to increase chromatin accessibility and activate the expression of their target genes. These target genes include multiple metastasis-promoting genes, such as TNC, MMP2, and VEGFA, and cytokine genes CSF1 and CXCL1, which are critical for immunosuppression at metastatic sites. Consistent with these results, pharmacological inhibition of CECR2 bromodomain impeded NF-κB-mediated immune suppression by macrophages and inhibited breast cancer metastasis. These results reveal that targeting CECR2 may be a strategy to treat metastatic breast cancer.
Sujet(s)
Tumeurs du sein , Facteur de transcription NF-kappa B , Animaux , Tumeurs du sein/anatomopathologie , Lignée cellulaire tumorale , Femelle , Humains , Immunosuppression thérapeutique , Macrophages/métabolisme , Souris , Facteur de transcription NF-kappa B/métabolisme , Métastase tumorale/anatomopathologie , Facteur de transcription RelA/métabolisme , Facteurs de transcriptionRÉSUMÉ
Tumours use various strategies to evade immune surveillance1,2. Immunotherapies targeting tumour immune evasion such as immune checkpoint blockade have shown considerable efficacy on multiple cancers3,4 but are ineffective for most patients due to primary or acquired resistance5-7. Recent studies showed that some epigenetic regulators suppress anti-tumour immunity2,8-12, suggesting that epigenetic therapies could boost anti-tumour immune responses and overcome resistance to current immunotherapies. Here we show that, in mouse melanoma models, depletion of KDM5B-an H3K4 demethylase that is critical for melanoma maintenance and drug resistance13-15-induces robust adaptive immune responses and enhances responses to immune checkpoint blockade. Mechanistically, KDM5B recruits the H3K9 methyltransferase SETDB1 to repress endogenous retroelements such as MMVL30 in a demethylase-independent manner. Derepression of these retroelements activates cytosolic RNA-sensing and DNA-sensing pathways and the subsequent type-I interferon response, leading to tumour rejection and induction of immune memory. Our results demonstrate that KDM5B suppresses anti-tumour immunity by epigenetic silencing of retroelements. We therefore reveal roles of KDM5B in heterochromatin regulation and immune evasion in melanoma, opening new paths for the development of KDM5B-targeting and SETDB1-targeting therapies to enhance tumour immunogenicity and overcome immunotherapy resistance.
Sujet(s)
Protéines de liaison à l'ADN/métabolisme , Extinction de l'expression des gènes , Histone-lysine N-methyltransferase/métabolisme , Jumonji Domain-Containing Histone Demethylases/métabolisme , Mélanome/immunologie , Rétroéléments , Échappement de la tumeur à la surveillance immunitaire , Animaux , Lignée cellulaire tumorale , Épigenèse génétique , Hétérochromatine , Humains , Interféron de type I/immunologie , Mâle , Souris , Souris de lignée C57BL , Souris knockout , Protéines nucléaires , Protéines de répressionRÉSUMÉ
Autophagy is a critical survival factor for cancer cells, whereby it maintains cellular homeostasis by degrading damaged organelles and unwanted proteins and supports cellular biosynthesis in response to stress. Cancer cells, including hepatocellular carcinoma (HCC), are often situated in a hypoxic, nutrient-deprived and stressful microenvironment where tumor cells are yet still able to adapt and survive. However, the mechanism underlying this adaptation and survival is not well-defined. We report deficiency of the post-translational modification enzyme protein arginine N-methyltransferase 6 (PRMT6) in HCC to promote the induction of autophagy under oxygen/nutrient-derived and sorafenib drug-induced stress conditions. Enhanced autophagic flux in HCC cells negatively correlated with PRMT6 expression, with the catalytic domain of PRMT6 critically important in mediating these autophagic activities. Mechanistically, PRMT6 physically interacts and methylates BAG5 to enhance the degradation of its interacting partner HSC70, a well-known autophagy player. The therapeutic potential of targeting BAG5 using genetic approach to reverse tumorigenicity and sorafenib resistance mediated by PRMT6 deficiency in HCC is also demonstrated in an in vivo model. The clinical implications of these findings are highlighted by the inverse correlative expressions of PRMT6 and HSC70 in HCC tissues. Collectively, deficiency of PRMT6 induces autophagy to promote tumorigenicity and cell survival in hostile microenvironments of HCC tumors by regulating BAG5-associated HSC70 stability through post-translational methylation of BAG5. Targeting BAG5 may therefore be an attractive strategy in HCC treatment by suppressing autophagy and inducing HCC cell sensitivity to sorafenib for treatment.
Sujet(s)
Protéines adaptatrices de la transduction du signal/métabolisme , Carcinome hépatocellulaire/anatomopathologie , Résistance aux médicaments antinéoplasiques , Protéines du choc thermique HSC70/composition chimique , Tumeurs du foie/anatomopathologie , Protéines nucléaires/composition chimique , Protéines nucléaires/métabolisme , Protein-arginine N-methyltransferases/composition chimique , Protein-arginine N-methyltransferases/métabolisme , Protéines adaptatrices de la transduction du signal/composition chimique , Protéines adaptatrices de la transduction du signal/génétique , Animaux , Autophagie , Carcinome hépatocellulaire/génétique , Carcinome hépatocellulaire/métabolisme , Lignée cellulaire tumorale , Cellules HepG2 , Humains , Tumeurs du foie/génétique , Tumeurs du foie/métabolisme , Mâle , Méthylation , Souris , Transplantation tumorale , Stabilité protéique , Génétique inverse , Sorafénib/pharmacologieRÉSUMÉ
BACKGROUND AND AIMS: Most tumor cells use aerobic glycolysis (the Warburg effect) to support anabolic growth and promote tumorigenicity and drug resistance. Intriguingly, the molecular mechanisms underlying this phenomenon are not well understood. In this work, using gain-of-function and loss-of-function in vitro studies in patient-derived organoid and cell cultures as well as in vivo positron emission tomography-magnetic resonance imaging animal models, we showed that protein arginine N-methyltransferase 6 (PRMT6) regulates aerobic glycolysis in human hepatocellular carcinoma (HCC) through nuclear relocalization of pyruvate kinase M2 isoform (PKM2), a key regulator of the Warburg effect. APPROACH AND RESULTS: We found PRMT6 to methylate CRAF at arginine 100, interfering with its RAS/RAF binding potential, and therefore altering extracellular signal-regulated kinase (ERK)-mediated PKM2 translocation into the nucleus. This altered PRMT6-ERK-PKM2 signaling axis was further confirmed in both a HCC mouse model with endogenous knockout of PRMT6 as well as in HCC clinical samples. We also identified PRMT6 as a target of hypoxia through the transcriptional repressor element 1-silencing transcription factor, linking PRMT6 with hypoxia in driving glycolytic events. Finally, we showed as a proof of concept the therapeutic potential of using 2-deoxyglucose, a glycolysis inhibitor, to reverse tumorigenicity and sorafenib resistance mediated by PRMT6 deficiency in HCC. CONCLUSIONS: Our findings indicate that the PRMT6-ERK-PKM2 regulatory axis is an important determinant of the Warburg effect in tumor cells, and provide a mechanistic link among tumorigenicity, sorafenib resistance, and glucose metabolism.
Sujet(s)
Carcinogenèse , Carcinome hépatocellulaire/métabolisme , Carcinome hépatocellulaire/anatomopathologie , Tumeurs du foie/métabolisme , Tumeurs du foie/anatomopathologie , Protéines nucléaires/métabolisme , Protein-arginine N-methyltransferases/métabolisme , Protéines proto-oncogènes c-raf/métabolisme , Effet Warburg en oncologie , Transport nucléaire actif , Noyau de la cellule/enzymologie , Extracellular Signal-Regulated MAP Kinases/métabolisme , Cellules HepG2 , Humains , Méthylation , Pyruvate kinase/métabolismeRÉSUMÉ
Arginine methylation is a post-translational modification that plays pivotal roles in signal transduction and gene transcription during cell fate determination. We found protein methyltransferase 6 (PRMT6) to be frequently downregulated in hepatocellular carcinoma (HCC) and its expression to negatively correlate with aggressive cancer features in HCC patients. Silencing of PRMT6 promoted the tumor-initiating, metastasis, and therapy resistance potential of HCC cell lines and patient-derived organoids. Consistently, loss of PRMT6 expression aggravated liver tumorigenesis in a chemical-induced HCC PRMT6 knockout (PRMT6-/-) mouse model. Integrated transcriptome and protein-protein interaction studies revealed an enrichment of genes implicated in RAS signaling and showed that PRMT6 interacted with CRAF on arginine 100, which decreased its RAS binding potential and altered its downstream MEK/ERK signaling. Our work describes a critical repressive function for PRMT6 in maintenance of HCC cells by regulating RAS binding and MEK/ERK signaling via methylation of CRAF on arginine 100.
Sujet(s)
Carcinome hépatocellulaire/anatomopathologie , Méthylation de l'ADN , Régulation de l'expression des gènes tumoraux , Cellules souches tumorales/anatomopathologie , Protéines nucléaires/métabolisme , Protein-arginine N-methyltransferases/métabolisme , Facteur-3 associé aux récepteurs de TNF/génétique , Animaux , Apoptose , Carcinome hépatocellulaire/génétique , Carcinome hépatocellulaire/métabolisme , Prolifération cellulaire , Humains , Tumeurs du foie/génétique , Tumeurs du foie/métabolisme , Tumeurs du foie/anatomopathologie , MAP Kinase Kinase 1/génétique , MAP Kinase Kinase 1/métabolisme , Système de signalisation des MAP kinases , Mâle , Souris , Souris de lignée BALB C , Souris de lignée NOD , Souris knockout , Souris nude , Souris SCID , Cellules souches tumorales/métabolisme , Protéines nucléaires/génétique , Protein-arginine N-methyltransferases/génétique , Protein-arginine N-methyltransferases/physiologie , Cellules cancéreuses en culture , Tests d'activité antitumorale sur modèle de xénogreffe , Kinases raf/génétique , Kinases raf/métabolisme , Protéines G ras/génétique , Protéines G ras/métabolismeRÉSUMÉ
BACKGROUND: We aimed to evaluate a novel method of atrial fibrillation (AF) screening using an iPhone camera to detect and analyze photoplethysmographic signals from the face without physical contact by extracting subtle beat-to-beat variations of skin color that reflect the cardiac pulsatile signal. METHODS AND RESULTS: Patients admitted to the cardiology ward of the hospital for clinical reasons were recruited. Simultaneous facial and fingertip photoplethysmographic measurements were obtained from 217 hospital inpatients (mean age, 70.3±13.9 years; 71.4% men) facing the front camera and with an index finger covering the back camera of 2 independent iPhones before a 12-lead ECG was recorded. Backdrop and background light intensity was monitored during signal acquisition. Three successive 20-second (total, 60 seconds) recordings were acquired per patient and analyzed for heart rate regularity by Cardiio Rhythm (Cardiio Inc, Cambridge, MA) smartphone application. Pulse irregularity in ≥1 photoplethysmographic readings or 3 uninterpretable photoplethysmographic readings were considered a positive AF screening result. AF was present on 12-lead ECG in 34.6% (n=75/217) patients. The Cardiio Rhythm facial photoplethysmographic application demonstrated high sensitivity (95%; 95% confidence interval, 87%-98%) and specificity (96%; 95% confidence interval, 91%-98%) in discriminating AF from sinus rhythm compared with 12-lead ECG. The positive and negative predictive values were 92% (95% confidence interval, 84%-96%) and 97% (95% confidence interval, 93%-99%), respectively. CONCLUSIONS: Detection of a facial photoplethysmographic signal to determine pulse irregularity attributable to AF is feasible. The Cardiio Rhythm smartphone application showed high sensitivity and specificity, with low negative likelihood ratio for AF from facial photoplethysmographic signals. The convenience of a contact-free approach is attractive for community screening and has the potential to be useful for distant AF screening.
Sujet(s)
Algorithmes , Fibrillation auriculaire/diagnostic , Face/physiopathologie , Rythme cardiaque/physiologie , Dépistage de masse/méthodes , Photopléthysmographie/méthodes , Ordiphone , Sujet âgé , Fibrillation auriculaire/physiopathologie , Électrocardiographie , Conception d'appareillage , Femelle , Humains , Mâle , Applications mobiles , Valeur prédictive des tests , Reproductibilité des résultats , Études rétrospectivesRÉSUMÉ
Identifying critical factors involved in the metastatic progression of hepatocellular carcinoma (HCC) may offer important therapeutic opportunities. Here, we report that the proapoptotic stress response factor TP53INP1 is often selectively downregulated in advanced stage IV and metastatic human HCC tumors. Mechanistic investigations revealed that TP53INP1 downregulation in early-stage HCC cells promoted metastasis via DUSP10 phosphatase-mediated activation of the ERK pathway. The DUSP10 promoter included putative binding sites for p73 directly implicated in modulation by TP53INP1. Overall, our findings show how TP53INP1 plays a critical role in limiting the progression of early-stage HCC, with implications for developing new therapeutic strategies to attack metastatic HCC. Cancer Res; 77(17); 4602-12. ©2017 AACR.
Sujet(s)
Carcinome hépatocellulaire/anatomopathologie , Protéines de transport/métabolisme , Dual-specificity phosphatases/métabolisme , Protéines du choc thermique/métabolisme , Tumeurs du poumon/secondaire , Mitogen-Activated Protein Kinase 1/métabolisme , Mitogen-Activated Protein Kinase 3/métabolisme , Mitogen-Activated Protein Kinase Phosphatases/métabolisme , Protéine tumorale p73/métabolisme , Animaux , Carcinome hépatocellulaire/génétique , Carcinome hépatocellulaire/métabolisme , Protéines de transport/génétique , Dual-specificity phosphatases/génétique , Analyse de profil d'expression de gènes , Protéines du choc thermique/génétique , Humains , Tumeurs du foie/génétique , Tumeurs du foie/métabolisme , Tumeurs du foie/anatomopathologie , Tumeurs du poumon/génétique , Tumeurs du poumon/métabolisme , Souris , Souris de lignée BALB C , Souris nude , Mitogen-Activated Protein Kinase 1/génétique , Mitogen-Activated Protein Kinase 3/génétique , Mitogen-Activated Protein Kinase Phosphatases/génétique , Métastase tumorale , Pronostic , Analyse par réseau de protéines , Transduction du signal , Cellules cancéreuses en culture , Protéine tumorale p73/génétique , Tests d'activité antitumorale sur modèle de xénogreffeRÉSUMÉ
Hepatocellular carcinoma (HCC), a highly malignant disease and the third leading cause of all cancer mortalities worldwide, often responses poorly to current treatments and results in dismal outcomes due to frequent chemoresistance and tumor relapse. The heterogeneity of HCC is an important attribute of the disease. It is the outcome of many factors, including the cross-talk between tumor cells within the tumor microenvironment and the acquisition and accumulation of genetic and epigenetic alterations in tumor cells. In addition, there is accumulating evidence in recent years to show that the malignancy of HCC can be attributed partly to the presence of cancer stem cell (CSC). CSCs are capable to self-renew, differentiate and initiate tumor formation. The regulation of the stem cell-like properties by several important signaling pathways have been found to endow the tumor cells with an increased level of tumorigenicity, chemoresistance, and metastatic ability. In this review, we will discuss the recent findings on hepatic CSCs, with special emphasis on their putative origins, relationship with hepatitis viruses, regulatory signaling networks, tumor microenvironment, and how these factors control the stemness of hepatic CSCs. We will also discuss some novel therapeutic strategies targeted at hepatic CSCs for combating HCC and perspectives of future investigation.