RESUMO
Therapy of BRAF-mutant melanoma with selective inhibitors of BRAF (BRAFi) and MEK (MEKi) represents a major clinical advance but acquired resistance to therapy has emerged as a key obstacle. To date, no clinical approaches successfully resensitize to BRAF/MEK inhibition. Here, we develop a therapeutic strategy for melanoma using bromosporine, a bromodomain inhibitor. Bromosporine (bromo) monotherapy produced significant anti-tumor effects against established melanoma cell lines and patient-derived xenografts (PDXs). Combinatorial therapy involving bromosporine and cobimetinib (bromo/cobi) showed synergistic anti-tumor effects in multiple BRAFi-resistant PDX models. The bromo/cobi combination was superior in vivo to standard BRAFi/MEKi therapy in the treatment-naive BRAF-mutant setting and to MEKi alone in the setting of immunotherapy-resistant NRAS- and NF1-mutant melanoma. RNA sequencing of xenografts treated with bromo/cobi revealed profound down-regulation of genes critical to cell division and mitotic progression. Bromo/cobi treatment resulted in marked DNA damage and cell-cycle arrest, resulting in induction of apoptosis. These studies introduce bromodomain inhibition, alone or combined with agents targeting the mitogen activated protein kinase pathway, as a rational therapeutic approach for melanoma refractory to standard targeted or immunotherapeutic approaches.
Assuntos
Melanoma , Proteínas Proto-Oncogênicas B-raf , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/patologia , Quinases de Proteína Quinase Ativadas por Mitógeno , Proteínas Nucleares , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/metabolismo , Fatores de TranscriçãoRESUMO
BACKGROUND: While melanomas commonly harbor losses of 9p21, on which CDKN2A resides, the presence of additional tumor suppressor elements at this locus is incompletely characterized. Here we assess the expression levels and functional role of microRNA-876-3p (miR-876), whose gene also maps to 9p21. METHODS: Expression of miR-876 was assessed in human tissues and cell lines using quantitative miRNA reverse transcriptase polymerase chain reaction (qRT-PCR). MIR876 copy number was determined in The Cancer Genome Atlas (TCGA) melanoma cohort. The consequences of regulation of miR-876 expression were assessed on melanoma cell colony formation, migration, invasion, apoptosis, cell cycle progression, and drug sensitivity in culture, and on in vivo tumor growth in a xenograft model. Genome-wide transcriptomic changes induced by miR-876 overexpression were determined using RNA sequencing (RNA-Seq). RESULTS: miR-876 expression was significantly decreased in primary melanoma samples when compared with nevi, and in human melanoma cell lines when compared with human melanocytes. Analysis of the TCGA cohort revealed deletions in MIR876 in > 50% of melanomas. miR-876 overexpression resulted in decreased melanoma cell colony formation, migration, and invasion, which was accompanied by cell cycle arrest and increased apoptosis. Intra-tumoral injections of miR-876 significantly suppressed melanoma growth in vivo. RNA-Seq analysis of miR-876-treated tumors revealed downregulation of several growth-promoting genes, along with upregulation of tumor suppressor genes, which was confirmed by qRT-PCR analysis. Computational analyses identified MAPK1 (or ERK2) as a possible target of miR-876 action. Overexpression of miR-876 significantly suppressed luciferase expression driven by the MAPK1/ERK2 3' UTR, and resulted in decreased ERK protein expression in melanoma cells. MAPK1/ERK2 cDNA overexpression rescued the effects of miR-876 on melanoma colony formation. miR-876 overexpression sensitized melanoma cells to treatment with the BRAF inhibitor vemurafenib. CONCLUSIONS: These studies identify miR-876 as a distinct tumor suppressor on 9p21 that is inactivated in melanoma and suggest miR-876 loss as an additional mechanism to activate ERK and the mitogen activated protein kinase (MAPK) pathway in melanoma. In addition, they suggest the therapeutic potential of combining miR-876 overexpression with BRAF inhibition as a rational therapeutic strategy for melanoma.
Assuntos
Cromossomos Humanos Par 9 , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Melanoma , MicroRNAs , Humanos , Melanoma/genética , Melanoma/patologia , MicroRNAs/genética , MicroRNAs/metabolismo , Linhagem Celular Tumoral , Animais , Cromossomos Humanos Par 9/genética , Movimento Celular/genética , Apoptose/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proliferação de Células/genética , Sequência de Bases , Invasividade NeoplásicaRESUMO
The invasive behavior of glioblastoma is essential to its aggressive potential. Here, we show that pleckstrin homology domain interacting protein (PHIP), acting through effects on the force transduction layer of the focal adhesion complex, drives glioblastoma motility and invasion. Immunofluorescence analysis localized PHIP to the leading edge of glioblastoma cells, together with several focal adhesion proteins: vinculin (VCL), talin 1 (TLN1), integrin beta 1 (ITGB1), as well as phosphorylated forms of paxillin (pPXN) and focal adhesion kinase (pFAK). Confocal microscopy specifically localized PHIP to the force transduction layer, together with TLN1 and VCL. Immunoprecipitation revealed a physical interaction between PHIP and VCL. Targeted suppression of PHIP resulted in significant down-regulation of these focal adhesion proteins, along with zyxin (ZYX), and produced profoundly disorganized stress fibers. Live-cell imaging of glioblastoma cells overexpressing a ZYX-GFP construct demonstrated a role for PHIP in regulating focal adhesion dynamics. PHIP silencing significantly suppressed the migratory and invasive capacity of glioblastoma cells, partially restored following TLN1 or ZYX cDNA overexpression. PHIP knockdown produced substantial suppression of tumor growth upon intracranial implantation, as well as significantly reduced microvessel density and secreted VEGF levels. PHIP copy number was elevated in the classical glioblastoma subtype and correlated with elevated EGFR levels. These results demonstrate PHIP's role in regulating the actin cytoskeleton, focal adhesion dynamics, and tumor cell motility, and identify PHIP as a key driver of glioblastoma migration and invasion.
Assuntos
Neoplasias Encefálicas/patologia , Adesões Focais/patologia , Glioblastoma/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neovascularização Patológica/patologia , Citoesqueleto de Actina/metabolismo , Animais , Encéfalo/patologia , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/genética , Adesão Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Estudos de Coortes , Progressão da Doença , Feminino , Dosagem de Genes , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioblastoma/irrigação sanguínea , Glioblastoma/genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Microscopia Intravital , Camundongos , Microscopia Confocal , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Neovascularização Patológica/genética , Imagem com Lapso de Tempo , Vinculina/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND AND AIMS: Cholangiocarcinoma (CCA) is a devastating disease often detected at advanced stages when surgery cannot be performed. Conventional and targeted systemic therapies perform poorly, and therefore effective drugs are urgently needed. Different epigenetic modifications occur in CCA and contribute to malignancy. Targeting epigenetic mechanisms may thus open therapeutic opportunities. However, modifications such as DNA and histone methylation often coexist and cooperate in carcinogenesis. We tested the therapeutic efficacy and mechanism of action of a class of dual G9a histone-methyltransferase and DNA-methyltransferase 1 (DNMT1) inhibitors. APPROACH AND RESULTS: Expression of G9a, DNMT1, and their molecular adaptor, ubiquitin-like with PHD and RING finger domains-1 (UHRF1), was determined in human CCA. We evaluated the effect of individual and combined pharmacological inhibition of G9a and DNMT1 on CCA cell growth. Our lead G9a/DNMT1 inhibitor, CM272, was tested in human CCA cells, patient-derived tumoroids and xenograft, and a mouse model of cholangiocarcinogenesis with hepatocellular deletion of c-Jun-N-terminal-kinase (Jnk)-1/2 and diethyl-nitrosamine (DEN) plus CCl4 treatment (JnkΔhepa + DEN + CCl4 mice). We found an increased and correlative expression of G9a, DNMT1, and UHRF1 in CCAs. Cotreatment with independent pharmacological inhibitors G9a and DNMT1 synergistically inhibited CCA cell growth. CM272 markedly reduced CCA cell proliferation and synergized with Cisplatin and the ERBB-targeted inhibitor, Lapatinib. CM272 inhibited CCA tumoroids and xenograft growth and significantly antagonized CCA progression in JnkΔhepa + DEN + CCl4 mice without apparent toxicity. Mechanistically, CM272 reprogrammed the tumoral metabolic transcriptome and phenotype toward a differentiated and quiescent status. CONCLUSIONS: Dual targeting of G9a and DNMT1 with epigenetic small molecule inhibitors such as CM272 is a potential strategy to treat CCA and/or enhance the efficacy of other systemic therapies.
Assuntos
Neoplasias dos Ductos Biliares , Proliferação de Células/efeitos dos fármacos , Colangiocarcinoma , DNA (Citosina-5-)-Metiltransferase 1 , Inibidores Enzimáticos/farmacologia , Antígenos de Histocompatibilidade , Histona-Lisina N-Metiltransferase , Animais , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Linhagem Celular Tumoral , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/antagonistas & inibidores , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Metilação de DNA/efeitos dos fármacos , Metilação de DNA/fisiologia , Epigênese Genética/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Antígenos de Histocompatibilidade/metabolismo , Código das Histonas/efeitos dos fármacos , Código das Histonas/fisiologia , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Camundongos , Resultado do Tratamento , Ubiquitina-Proteína Ligases/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
The identification and targeting of key molecular drivers of melanoma and breast and lung cancer have substantially improved their therapy. However, subtypes of each of these three common, lethal solid tumors lack identified molecular drivers, and are thus not amenable to targeted therapies. Here we show that pleckstrin homology domain-interacting protein (PHIP) promotes the progression of these "driver-negative" tumors. Suppression of PHIP expression significantly inhibited both tumor cell proliferation and invasion, coordinately suppressing phosphorylated AKT, cyclin D1, and talin1 expression in all three tumor types. Furthermore, PHIP's targetable bromodomain is functional, as it specifically binds the histone modification H4K91ac. Analysis of TCGA profiling efforts revealed PHIP overexpression in triple-negative and basal-like breast cancer, as well as in the bronchioid subtype of nonsmall cell lung cancer. These results identify a role for PHIP in the progression of melanoma and breast and lung cancer subtypes lacking identified targeted therapies. The use of selective, anti-PHIP bromodomain inhibitors may thus yield a broad-based, molecularly targeted therapy against currently nontargetable tumors.
Assuntos
Mama/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Pulmonares/metabolismo , Melanoma/metabolismo , Domínios de Homologia à Plecstrina/fisiologia , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Ciclina D1/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
BACKGROUND: Patient-derived xenograft (PDX) mouse tumour models can predict response to therapy in patients. Predictions made from PDX cultures (PDXC) would allow for more rapid and comprehensive evaluation of potential treatment options for patients, including drug combinations. METHODS: We developed a PDX library of BRAF-mutant metastatic melanoma, and a high-throughput drug-screening (HTDS) platform utilising clinically relevant drug exposures. We then evaluated 34 antitumor agents across eight melanoma PDXCs, compared drug response to BRAF and MEK inhibitors alone or in combination with PDXC and the corresponding PDX, and investigated novel drug combinations targeting BRAF inhibitor-resistant melanoma. RESULTS: The concordance of cancer-driving mutations across patient, matched PDX and subsequent PDX generations increases as variant allele frequency (VAF) increases. There was a high correlation in the magnitude of response to BRAF and MEK inhibitors between PDXCs and corresponding PDXs. PDXCs and corresponding PDXs from metastatic melanoma patients that progressed on standard-of-care therapy demonstrated similar resistance patterns to BRAF and MEK inhibitor therapy. Importantly, HTDS identified novel drug combinations to target BRAF-resistant melanoma. CONCLUSIONS: The biological consistency observed between PDXCs and PDXs suggests that PDXCs may allow for a rapid and comprehensive identification of treatments for aggressive cancers, including combination therapies.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Melanoma/tratamento farmacológico , Animais , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , MAP Quinase Quinase Quinases/antagonistas & inibidores , Melanoma/enzimologia , Melanoma/genética , Melanoma/patologia , Camundongos , Mutação , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/genética , Distribuição Aleatória , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Microphthalmia-associated transcription factor (MITF) plays a critical and complex role in melanocyte transformation. Although several downstream targets of MITF action have been identified, the precise mechanisms by which MITF promotes melanocytic tumor progression are incompletely understood. Recent studies identified an oncogenic role for the bromodomain plant homeodomain finger transcription factor (BPTF) gene in melanoma progression, in part through activation of BCL2, a canonical target of MITF signaling. Analysis of the BPTF promoter identified a putative MITF-binding site, suggesting that MITF may regulate BPTF expression. Overexpression of MITF resulted in up-regulation of BPTF in a panel of melanoma and melanocyte cell lines. shRNA-mediated down-regulation of MITF in melanoma cells was accompanied by down-regulation of BPTF and BPTF-regulated genes (including BCL2) and resulted in reduced proliferative capacity of melanoma cells. The suppression of cell growth mediated by MITF silencing was rescued by overexpression of BPTF cDNA. Binding of MITF to the BPTF promoter was demonstrated using ChIP analysis. MITF overexpression resulted in direct transcriptional activation of BPTF, as evidenced by increased luciferase activity driven by the BPTF promoter. These results indicate that BPTF transduces key prosurvival signals driven by MITF, further supporting its important role in promoting melanoma cell survival and progression.
Assuntos
Antígenos Nucleares/metabolismo , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Melanócitos/citologia , Melanoma/patologia , Fator de Transcrição Associado à Microftalmia/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fatores de Transcrição/metabolismo , Antígenos Nucleares/genética , Apoptose , Sítios de Ligação , Western Blotting , Células Cultivadas , Imunoprecipitação da Cromatina , Imunofluorescência , Humanos , Luciferases/metabolismo , Melanócitos/metabolismo , Melanoma/genética , Melanoma/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Proteínas do Tecido Nervoso/genética , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fatores de Transcrição/genética , Ativação TranscricionalRESUMO
MicroRNAs (miRNAs) play a key role in cancer progression by coordinately repressing target genes involved in cell proliferation, migration, and invasion. miRNAs regulate gene expression by repressing translation or directing sequence-specific degradation of complementary mRNA. Here, we report that expression of miR-1280 is significantly suppressed in human melanoma specimens when compared with nevi, and in human melanoma cell lines when compared with cultured normal human melanocytes. The proto-oncogene Src was identified as a target of miR-1280 action. Levels of Src expression were significantly higher in melanoma samples and cell lines than in nevi and normal melanocytes. miR-1280 overexpression significantly suppressed the luciferase activity of reporter plasmids containing the full-length 3' untranslated region of Src. miR-1280-mediated suppression of Src led to substantial decreases in melanoma cell proliferation, cell cycle progression, invasion, as well as induced melanoma cell apoptosis. The effects of miR-1280 overexpression on melanoma cell proliferation and growth were reversed by Src overexpression. Intratumoral delivery of miR-1280 significantly suppressed melanoma cell growth in vivo. Our results demonstrate a novel role for miR-1280 as a tumor suppressor in melanoma, identify the Src signaling pathway as a target of miR-1280 action, and suggest a potential therapeutic role for miR-1280 in melanoma.
Assuntos
Regulação Neoplásica da Expressão Gênica , Melanoma/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas pp60(c-src)/genética , Neoplasias Cutâneas/genética , Regiões 3' não Traduzidas , Animais , Apoptose , Sequência de Bases , Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Genes Reporter , Humanos , Luciferases/genética , Luciferases/metabolismo , Melanoma/metabolismo , Melanoma/patologia , Camundongos , Camundongos Nus , MicroRNAs/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas pp60(c-src)/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Although melanomas with mutant v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) can now be effectively targeted, there is no molecular target for most melanomas expressing wild-type BRAF. Here, we show that the activation of Pleckstrin homology domain-interacting protein (PHIP), promotes melanoma metastasis, can be used to classify a subset of primary melanomas, and is a prognostic biomarker for melanoma. Systemic, plasmid-based shRNA targeting of Phip inhibited the metastatic progression of melanoma, whereas stable suppression of Phip in melanoma cell lines suppressed metastatic potential and prolonged the survival of tumor-bearing mice. The human PHIP gene resides on 6q14.1, and although 6q loss has been observed in melanoma, the PHIP locus was preserved in melanoma cell lines and patient samples, and its overexpression was an independent adverse predictor of survival in melanoma patients. In addition, a high proportion of PHIP-overexpressing melanomas harbored increased PHIP copy number. PHIP-overexpressing melanomas include tumors with wild-type BRAF, neuroblastoma RAS viral (v-ras) oncogene homolog, and phosphatase and tensin homolog, demonstrating PHIP activation in triple-negative melanoma. These results describe previously unreported roles for PHIP in predicting and promoting melanoma metastasis, and in the molecular classification of melanoma.
Assuntos
Biomarcadores Tumorais/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/secundário , Melanoma/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Sequência de Bases , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/genética , Melanoma/genética , Melanoma/secundário , Melanoma Experimental/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/genética , RNA Interferente Pequeno/genética , Transdução de SinaisRESUMO
As a result of tumor heterogeneity and solid cancers harboring multiple molecular defects, precision medicine platforms in oncology are most effective when both genetic and pharmacologic determinants of a tumor are evaluated. Expandable patient-derived xenograft (PDX) mouse tumor and corresponding PDX culture (PDXC) models recapitulate many of the biological and genetic characteristics of the original patient tumor, allowing for a comprehensive pharmacogenomic analysis. Here, the somatic mutations of 23 matched patient tumor and PDX samples encompassing four cancers were first evaluated using next-generation sequencing (NGS). 19 antitumor agents were evaluated across 78 patient-derived tumor cultures using clinically relevant drug exposures. A binarization threshold sensitivity classification determined in culture (PDXC) was used to identify tumors that best respond to drug in vivo (PDX). Using this sensitivity classification, logic models of DNA mutations were developed for 19 antitumor agents to predict drug response. We determined that the concordance of somatic mutations across patient and corresponding PDX samples increased as variant allele frequency increased. Notable individual PDXC responses to specific drugs, as well as lineage-specific drug responses were identified. Robust responses identified in PDXC were recapitulated in vivo in PDX-bearing mice and logic modeling determined somatic gene mutation(s) defining response to specific antitumor agents. In conclusion, combining NGS of primary patient tumors, high-throughput drug screen using clinically relevant doses, and logic modeling, can provide a platform for understanding response to therapeutic drugs targeting cancer.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Animais , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto , Testes Farmacogenômicos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Antineoplásicos/farmacologia , MutaçãoRESUMO
MicroRNAs (miRNAs) regulate gene expression by repressing translation or directing sequence-specific degradation of complementary mRNA. Here, we report that expression of miR-205 is significantly suppressed in melanoma specimens when compared with nevi and is correlated inversely with melanoma progression. miRNA target databases predicted E2F1 and E2F5 as putative targets. The expression levels of E2F1 and E2F5 were correlated inversely with that of miR-205 in melanoma cell lines. miR-205 significantly suppressed the luciferase activity of reporter plasmids containing the 3'-UTR sequences complementary to either E2F1 or E2F5. Overexpression of miR-205 in melanoma cells reduced E2F1 and E2F5 protein levels. The proliferative capacity of melanoma cells was suppressed by miR-205 and mediated by E2F-regulated AKT phosphorylation. miR-205 overexpression resulted in induction of apoptosis, as evidenced by increased cleaved caspase-3, poly-(ADP-ribose) polymerase, and cytochrome c release. Stable overexpression of miR-205 suppressed melanoma cell proliferation, colony formation, and tumor cell growth in vivo and induced a senescence phenotype accompanied by elevated expression of p16INK4A and other markers for senescence. E2F1 overexpression in miR-205-expressing cells partially reversed the effects on melanoma cell growth and senescence. These results demonstrate a novel role for miR-205 as a tumor suppressor in melanoma.
Assuntos
Fator de Transcrição E2F1/metabolismo , Regulação Neoplásica da Expressão Gênica , Melanoma/metabolismo , MicroRNAs/metabolismo , Neoplasias Cutâneas/metabolismo , Regiões 3' não Traduzidas , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Senescência Celular , Fator de Transcrição E2F5/metabolismo , Humanos , Modelos Biológicos , Poli(ADP-Ribose) Polimerases/metabolismoRESUMO
Purpose: To assess the biomarker and functional role of the chromatin remodeling factor, bromodomain PHD finger transcription factor (BPTF), in breast cancer progression. Methods: BPTF copy number was assessed using fluorescence in situ hybridization. BPTF expression was regulated in breast cancer cells by shRNA/siRNA-mediated gene silencing and BPTF cDNA overexpression. The effects of regulating BPTF expression were examined on key oncogenic signaling pathways and on breast cancer cell proliferation, apoptosis, and cell cycle progression, as well as in xenograft models. The consequences of pharmacological bromodomain inhibition, alone or in combination with other targeted agents, on breast cancer progression were assessed in culture and in xenograft models. Results: BPTF copy number was gained in 34.1% and separately amplified in 8.2% of a breast cancer tissue cohort. Elevated BPTF copy number was significantly associated with increasing patient age and tumor grade and observed in both ER-positive and triple-negative breast cancer (TNBC) subtypes. BPTF copy number gain and amplification were also observed in The Cancer Genome Atlas (TCGA) breast cancer cohort. Stable shRNA-mediated silencing of BPTF significantly inhibited cell proliferation and induced apoptosis in TNBC and ER-positive human breast cancer cell lines. BPTF knockdown suppressed signaling through the phosphoinositide 3 kinase (PI3K) pathway, including reduced expression of phosphorylated AKT (Ser473), phosphorylated GSK-ß (Ser9), and CCND1. These findings were confirmed following transient BPTF knockdown by a distinct siRNA in TNBC and ER-positive breast cancer cells. Stable suppression of BPTF expression significantly inhibited the in vivo growth of TNBC cells. Conversely, BPTF cDNA overexpression in TNBC and ER-positive breast cancer cells enhanced breast cancer cell proliferation and reduced apoptosis. BPTF targeting with the bromodomain inhibitor bromosporine, alone or in combination with the PI3K pathway inhibitor gedatolisib, produced significant anti-tumor effects against TNBC cells in vitro and in vivo. Conclusion: These studies demonstrate BPTF activation in distinct breast cancer subtypes, identify pathways by which BPTF promotes breast cancer progression, and suggest BPTF as a rational target for breast cancer therapy.
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We describe our institutional experience of developing a liquid biopsy approach using circulating tumor DNA (ctDNA) analysis for personalized medicine in cancer patients, focusing on the hurdles encountered during the multistep process in order to benefit other investigators wishing to set up this type of study in their institution. Blood samples were collected at the time of cancer surgery from 209 patients with one of nine different cancer types. Extracted tumor DNA and circulating cell-free DNA were sequenced using cancer-specific panels and the Illumina MiSeq machine. Almost half of the pairs investigated were uninformative, mostly because there was no trackable pathogenic mutation detected in the original tumor. The pairs with interpretable data corresponded to 107 patients. Analysis of 48 gene sequences common to both panels was performed and revealed that about 40% of these pairs contained at least one driver mutation detected in the DNA extracted from plasma. Here, we describe the choice of our overall approach, the selection of the cancer panels, and the difficulties encountered during the multistep process, including the use of several tumor types and in the data analysis. We also describe some case reports using longitudinal samples, illustrating the potential advantages and rewards in performing ctDNA sequencing to monitor tumor burden or guide treatment for cancer patients.
RESUMO
Cholangiocarcinoma (CCA) is the second most common hepatobiliary cancer, an aggressive malignancy with limited therapeutic options. PARP (poly (ADP-ribose) polymerase) 1 and 2 are important for deoxyribonucleotide acid (DNA) repair and maintenance of genomic stability. PARP inhibitors (PARPi) such as niraparib have been approved for different malignancies with genomic alteration in germline BRCA and DNA damage response (DDR) pathway genes. Genomic alterations were analyzed in DDR genes in CCA samples employing The Cancer Genome Atlas (TCGA) database. Mutations were observed in various DDR genes, and 35.8% cases had alterations in at least one of three genes (ARID1A, BAP1 and ATM), suggesting their susceptibility to PARPi. Niraparib treatment suppressed cancer cell viability and survival, and also caused G2/M cell cycle arrest in patient-derived xenograft cells lines (PDXC) and established CCA cells harboring DDR gene mutations. PARPi treatment also induced apoptosis and caspase3/7 activity in PDXC and CCA cell lines, and substantially reduced expression of BCL2, BCL-XL and MCL1 proteins. Niraparib caused a significant increase in oxidative stress, and induced activation of DNA damage markers, phosphorylation of CHK2 and replication fork stalling. Importantly, niraparib, in combination with gemcitabine, produced sustained and robust inhibition of tumor growth in vivo in a patient-derived xenograft (PDX) model more effectively than either treatment alone. Furthermore, tissue samples from mice treated with niraparib and gemcitabine display significantly lower expression levels of pHH3 and Ki-67, which are a mitotic and proliferative marker, respectively. Taken together, our results indicate niraparib as a novel therapeutic agent alone or in combination with gemcitabine for CCA.
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Melanoma occurs as a consequence of inherited susceptibility to the disease and exposure to UV radiation (UVR) and is characterized by uncontrolled cellular proliferation and a high mutational load. The precise mechanisms by which UVR contributes to the development of melanoma remain poorly understood. Here we show that activation of nuclear receptor coactivator 3 (NCOA3) promotes melanomagenesis through regulation of UVR sensitivity, cell-cycle progression, and circumvention of the DNA damage response (DDR). Downregulation of NCOA3 expression, either by genetic silencing or small-molecule inhibition, significantly suppressed melanoma proliferation in melanoma cell lines and patient-derived xenografts. NCOA3 silencing suppressed expression of xeroderma pigmentosum C and increased melanoma cell sensitivity to UVR. Suppression of NCOA3 expression led to activation of DDR effectors and reduced expression of cyclin B1, resulting in G2-M arrest and mitotic catastrophe. A SNP in NCOA3 (T960T) reduced NCOA3 protein expression and was associated with decreased melanoma risk, given a significantly lower prevalence in a familial melanoma cohort than in a control cohort without cancer. Overexpression of wild-type NCOA3 promoted melanocyte survival following UVR and was accompanied by increased levels of UVR-induced DNA damage, both of which were attenuated by overexpression of NCOA3 (T960T). These results describe NCOA3-regulated pathways by which melanoma can develop, with germline NCOA3 polymorphisms enabling enhanced melanocyte survival in the setting of UVR exposure, despite an increased mutational burden. They also identify NCOA3 as a novel therapeutic target for melanoma. SIGNIFICANCE: This study explores NCOA3 as a regulator of the DDR and a therapeutic target in melanoma, where activation of NCOA3 contributes to melanoma development following exposure to ultraviolet light.
Assuntos
Biomarcadores Tumorais/metabolismo , Dano ao DNA , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Melanoma/patologia , Coativador 3 de Receptor Nuclear/metabolismo , Lesões por Radiação/patologia , Raios Ultravioleta/efeitos adversos , Animais , Apoptose , Biomarcadores Tumorais/genética , Proliferação de Células , Feminino , Humanos , Melanoma/etiologia , Melanoma/metabolismo , Camundongos , Camundongos Nus , Mutação , Coativador 3 de Receptor Nuclear/genética , Lesões por Radiação/etiologia , Lesões por Radiação/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Homologous recombination DNA damage repair (HR-DDR) deficient patients with various solid tumors have been treated with PARP inhibitors. However, the clinical characteristics of patients with melanoma who have HR-DDR gene mutations and the consequences of PARP inhibition are poorly understood. We compared the commercially available next-generation sequencing data from 84 patients with melanomas from our institution with a dataset of 1,986 patients as well as 1,088 patients profiled in cBioportal. In total, 21.4% of patients had ≥1 functional HR-DDR mutation, most commonly involving BRCA1, ARID1A, ATM, ATR, and FANCA. Concurrent NF1, BRAF, and NRAS mutations were found in 39%, 39%, and 22% of cases, respectively. HR-DDR gene mutation was associated with high tumor mutational burden and clinical response to checkpoint blockade. A higher prevalence of HR-DDR mutations was observed in the datasets from Foundation Medicine (Cambridge, CA) and those from the Cancer Genome Atlas. Treatment of HR-DDRâmutated patient-derived xenograft models of melanoma with PARP inhibitor produced significant antitumor activity in vivo and was associated with increased apoptotic activity. RNA sequencing analysis of PARP inhibitor-treated tumors indicated alterations in the pathways involving extracellular matrix remodeling, cell adhesion, and cell-cycle progression. Melanomas with HR-DDR mutations represent a unique subset, which is more likely to benefit from checkpoint blockade and may be targeted with PARP inhibitor.
Assuntos
Biomarcadores Tumorais/genética , Melanoma/genética , Reparo de DNA por Recombinação/genética , Neoplasias Cutâneas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/metabolismo , Dano ao DNA/efeitos dos fármacos , Análise Mutacional de DNA/estatística & dados numéricos , Feminino , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Masculino , Melanoma/tratamento farmacológico , Melanoma/epidemiologia , Camundongos , Pessoa de Meia-Idade , Epidemiologia Molecular , Mutação , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Prevalência , Intervalo Livre de Progressão , RNA-Seq , Reparo de DNA por Recombinação/efeitos dos fármacos , Estudos Retrospectivos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/epidemiologia , Ensaios Antitumorais Modelo de Xenoenxerto , Adulto JovemRESUMO
IkappaBgamma is one member of a family of proteins that can inhibit the nuclear localization of nuclear factor-kappaB. However, the other specific functions of IkappaBgamma are still poorly understood, and its effects on tumor metastasis have not yet been characterized. We examined the consequences of targeting IkappaBgamma in melanoma cells using a hammerhead ribozyme. We developed stable transformant B16-F10 melanoma cell lines that express a ribozyme that targets mouse IkappaBgamma (IkappaBgamma-144-Rz). Tail-vein injection of B16-F10 cells that stably express IkappaBgamma-144-Rz into mice resulted in a significant reduction of the metastatic potential of these cells. IkappaBgamma-144-Rz-expressing B16 cells were shown to have increased transcriptional activity of nuclear factor-kappaB. We then showed that IkappaBgamma-144-Rz-expressing cells demonstrated both reduced invasion and increased apoptosis, suggesting the existence of pathways through which IkappaBgamma promotes melanoma metastasis. Using gene expression profiling, we identified a differentially expressed gene set that is regulated by the stable suppression of IkappaBgamma that may participate in mediating its anti-metastatic effects; we also confirmed the altered expression levels of several of these genes by quantitative real time polymerase chain reaction. Plasmid-mediated expression of IkappaBgamma-144-Rz produced a significant inhibition of the metastatic progression of B16-F10 cells to the lung and resulted in significant anti-invasive and pro-apoptotic effects on murine Lewis lung carcinoma cells. Our results suggest a novel role for IkappaBgamma in promoting the metastatic progression of melanoma.
Assuntos
Melanoma Experimental/genética , Melanoma Experimental/patologia , Subunidade p50 de NF-kappa B/genética , NF-kappa B/genética , Invasividade Neoplásica/prevenção & controle , Metástase Neoplásica/prevenção & controle , RNA Catalítico/genética , Animais , Clonagem Molecular , Citometria de Fluxo , Camundongos , NF-kappa B/antagonistas & inibidores , Invasividade Neoplásica/patologia , Metástase Neoplásica/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , RNA Neoplásico/genética , Transcrição Gênica , Células Tumorais CultivadasRESUMO
Cholangiocarcinoma (CCA) is a highly invasive cancer, diagnosed at an advanced stage, and refractory to surgical intervention and chemotherapy. Cyclin-dependent kinases (CDKs) regulate cell cycle progression and transcriptional processes, and are considered potential therapeutic targets for cancer. Dinaciclib is a small molecule multi-CDK inhibitor targeting CDK 2/5/9. In this study, the therapeutic efficacy of dinaciclib was assessed using patient-derived xenograft cells (PDXC) and CCA cell lines. Treatment with dinaciclib significantly suppressed cell proliferation, induced caspase 3/7 levels and apoptotic activity in PDXC and CCA cell lines. Dinaciclib suppressed expression of its molecular targets CDK2/5/9, and anti-apoptotic BCL-XL and BCL2 proteins. Despite the presence of cyclin D1 amplification in the PDXC line, palbociclib treatment had no effect on cell proliferation, cell cycle or apoptosis in the PDXC as well as other CCA cell lines. Importantly, dinaciclib, in combination with gemcitabine, produced a robust and sustained inhibition of tumor progression in vivo in a PDX mouse model, greater than either of the treatments alone. Expression levels of two proliferative markers, phospho-histone H3 and Ki-67, were substantially suppressed in samples treated with the combination regimen. Our results identify dinaciclib as a novel and potent therapeutic agent alone or in combination with gemcitabine for the treatment of CCA.
Assuntos
Neoplasias dos Ductos Biliares/tratamento farmacológico , Colangiocarcinoma/tratamento farmacológico , Óxidos N-Cíclicos/farmacologia , Quinase 2 Dependente de Ciclina/metabolismo , Quinase 5 Dependente de Ciclina/metabolismo , Quinase 9 Dependente de Ciclina/metabolismo , Neoplasias Gastrointestinais/tratamento farmacológico , Indolizinas/farmacologia , Compostos de Piridínio/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Histonas/metabolismo , Humanos , Concentração Inibidora 50 , Antígeno Ki-67 , Masculino , Camundongos , Camundongos Endogâmicos NOD , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína bcl-X/metabolismo , GencitabinaRESUMO
BTG3/ANA/APRO4 has been reported to be a tumor suppressor gene in some malignancies. It constitutes important negative regulatory mechanism for Src-mediated signaling, a negative regulator of the cell cycle and inhibits transcription factor E2F1. We report that BTG3 is downregulated in renal cancer and that the mechanism of inactivation is through promoter hypermethylation. Quantitative real-time polymerase chain reaction (PCR) showed that BTG3 was downregulated in cancer tissues and cells. Genistein and 5-aza-2'-deoxycytidine (5Aza-C) induced BTG3 messenger RNA (mRNA) expression in A498, ACHN and HEK-293 renal cell carcinoma (RCC) cell lines. Bisulfite-modified PCR and DNA sequencing results showed complete methylation of BTG3 promoter in tumor samples and cancer cell lines. Genistein and 5Aza-C treatment significantly decreased promoter methylation, reactivating BTG3 expression. Chromatin immunoprecipitation assay revealed that genistein and 5Aza-C increased levels of acetylated histones 3, 4, 2H3K4, 3H3K4 and RNA polymerase II at the BTG3 promoter indicative of active histone modifications. Enzymatic assays showed genistein and 5Aza-C decreased DNA Methyltransferase, methyl-CpG-binding domain 2 activity and increased HAT activity. Cell cycle and 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide cell proliferation assays showed that genistein has antiproliferative effect on cancer cell growth through induction of cell cycle arrest. This is the first report to show that BTG3 is epigenetically silenced in RCC and can be reactivated by genistein-induced promoter demethylation and active histone modification. Genistein had similar effects to that of 5Aza-C, which is a potent demethylating agent with high toxicity and instability. Genistein being a natural, non-toxic, dietary isoflavone is effective in retarding the growth of RCC cells, making it a promising candidate for epigenetic therapy in renal carcinoma.
Assuntos
Ciclo Celular/efeitos dos fármacos , Metilação de DNA , Genisteína/farmacologia , Histonas/metabolismo , Neoplasias Renais/genética , Regiões Promotoras Genéticas/genética , Proteínas/genética , Anticarcinógenos/farmacologia , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Proteínas de Ciclo Celular , Sobrevivência Celular/efeitos dos fármacos , Cromatina/genética , Imunoprecipitação da Cromatina , Metilases de Modificação do DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Decitabina , Inibidores Enzimáticos/farmacologia , Genes Supressores de Tumor , Humanos , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais CultivadasRESUMO
PURPOSE: We have investigated the role of t-DARPP in trastuzumab resistance in ERBB2-amplified and overexpressed breast cancer cell lines. EXPERIMENTAL DESIGN: We have used the HR-5 and HR-6 trastuzumab-resistant cells that were established from tumors that recurred in the presence of trastuzumab therapy following xenografts of BT-474 cells in nude mice. In addition, SKBR-3 cells, engineered for stable expression of t-DARPP, and HCC-1569 cells, which have constitutive expression of t-DARPP and are de novo resistant to trastuzumab, were used. RESULTS: We reported > or =15-fold up-regulation of mRNA and protein levels of t-DARPP in HR-5 and HR-6 cells compared with their progenitor BT-474 trastuzumab-sensitive cells. The t-DARPP expression was not regulated by changes in its promoter DNA methylation levels. The SKBR-3 cells stably expressing t-DARPP developed resistance to trastuzumab compared with their parental cells and empty vector controls (P < 0.01). The trastuzumab-resistant cell lines showed a significant increase in pAKT (Ser(473)) and BCL2 protein levels. The small interfering RNA knockdown of t-DARPP in all trastuzumab-resistant cells led to a significant reduction in ERBB2, pAKT (Ser(473)), and BCL2 protein levels with a significant decrease in cell viability (P < or = 0.001) and an increase in cleaved caspase-3 levels, indicating the progression of these cells toward apoptosis. The t-DARPP protein was associated with both heat shock protein 90 and ERBB2 forming a potential protein complex. This association may play a role in regulating ERBB2 protein in trastuzumab-resistant cells. CONCLUSION: We conclude that t-DARPP is a novel molecular target that can mediate the therapeutic resistance to trastuzumab in breast cancer cells.