RESUMO
Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.
Assuntos
Proteína BRCA2 , Neoplasias da Mama , Glicólise , Aldeído Pirúvico , Animais , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Camundongos , Humanos , Feminino , Aldeído Pirúvico/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Haploinsuficiência , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Mutação , Dano ao DNA , Reparo do DNA , Linhagem Celular TumoralRESUMO
The nuclear hormone receptor estrogen receptor alpha (ERα) is a well-known transcription factor present in many breast cancers, where it promotes cancer progression. In this issue of Cell, Xu et al. report that ERα is also an RNA-binding protein and that its post-transcriptional activity enables cancer cell fitness and survival.
Assuntos
Neoplasias da Mama , Receptores de Estrogênio , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Proliferação de Células , Receptor alfa de Estrogênio/genética , Feminino , Humanos , RNA/genética , Receptores de Estrogênio/genéticaRESUMO
Mary-Claire King's approach to genetics has had a major impact on breast and ovarian cancer and, more recently, mental illnesses including schizophrenia. Science writer Kendall Morgan talked with Mary-Claire, recipient of a 2021 Canada Gairdner International Award, about her life, her lengthy quest to discover the genetic basis of susceptibility to breast cancer, the struggles for women in science, and much more. An edited version of this conversation is presented below.
Assuntos
Neoplasias da Mama/patologia , Neoplasias Ovarianas/patologia , Distinções e Prêmios , Neoplasias da Mama/genética , Feminino , Genética , Humanos , Transtornos Mentais/genética , Transtornos Mentais/patologia , Neoplasias Ovarianas/genética , Esquizofrenia/genética , Esquizofrenia/patologiaRESUMO
Metastasis has been considered as the terminal step of tumor progression. However, recent genomic studies suggest that many metastases are initiated by further spread of other metastases. Nevertheless, the corresponding pre-clinical models are lacking, and underlying mechanisms are elusive. Using several approaches, including parabiosis and an evolving barcode system, we demonstrated that the bone microenvironment facilitates breast and prostate cancer cells to further metastasize and establish multi-organ secondary metastases. We uncovered that this metastasis-promoting effect is driven by epigenetic reprogramming that confers stem cell-like properties on cancer cells disseminated from bone lesions. Furthermore, we discovered that enhanced EZH2 activity mediates the increased stemness and metastasis capacity. The same findings also apply to single cell-derived populations, indicating mechanisms distinct from clonal selection. Taken together, our work revealed an unappreciated role of the bone microenvironment in metastasis evolution and elucidated an epigenomic reprogramming process driving terminal-stage, multi-organ metastases.
Assuntos
Neoplasias Ósseas/secundário , Neoplasias da Mama/patologia , Metástase Neoplásica , Neoplasias da Próstata/patologia , Microambiente Tumoral , Animais , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Proliferação de Células , Progressão da Doença , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Nus , Camundongos SCID , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Estrogen receptor α (ERα) is a hormone receptor and key driver for over 70% of breast cancers that has been studied for decades as a transcription factor. Unexpectedly, we discover that ERα is a potent non-canonical RNA-binding protein. We show that ERα RNA binding function is uncoupled from its activity to bind DNA and critical for breast cancer progression. Employing genome-wide cross-linking immunoprecipitation (CLIP) sequencing and a functional CRISPRi screen, we find that ERα-associated mRNAs sustain cancer cell fitness and elicit cellular responses to stress. Mechanistically, ERα controls different steps of RNA metabolism. In particular, we demonstrate that ERα RNA binding mediates alternative splicing of XBP1 and translation of the eIF4G2 and MCL1 mRNAs, which facilitates survival upon stress conditions and sustains tamoxifen resistance of cancer cells. ERα is therefore a multifaceted RNA-binding protein, and this activity transforms our knowledge of post-transcriptional regulation underlying cancer development and drug response.
Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Resistencia a Medicamentos Antineoplásicos , Receptor alfa de Estrogênio/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Sequência de Bases , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Receptor alfa de Estrogênio/química , Fator de Iniciação Eucariótico 4G/genética , Fator de Iniciação Eucariótico 4G/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genômica , Humanos , Camundongos Endogâmicos NOD , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Oncogenes , Ligação Proteica/efeitos dos fármacos , Domínios Proteicos , Splicing de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Tamoxifeno/farmacologia , Proteína 1 de Ligação a X-Box/metabolismoRESUMO
The integration of mass spectrometry-based proteomics with next-generation DNA and RNA sequencing profiles tumors more comprehensively. Here this "proteogenomics" approach was applied to 122 treatment-naive primary breast cancers accrued to preserve post-translational modifications, including protein phosphorylation and acetylation. Proteogenomics challenged standard breast cancer diagnoses, provided detailed analysis of the ERBB2 amplicon, defined tumor subsets that could benefit from immune checkpoint therapy, and allowed more accurate assessment of Rb status for prediction of CDK4/6 inhibitor responsiveness. Phosphoproteomics profiles uncovered novel associations between tumor suppressor loss and targetable kinases. Acetylproteome analysis highlighted acetylation on key nuclear proteins involved in the DNA damage response and revealed cross-talk between cytoplasmic and mitochondrial acetylation and metabolism. Our results underscore the potential of proteogenomics for clinical investigation of breast cancer through more accurate annotation of targetable pathways and biological features of this remarkably heterogeneous malignancy.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carcinogênese/genética , Carcinogênese/patologia , Terapia de Alvo Molecular , Proteogenômica , Desaminases APOBEC/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/imunologia , Neoplasias da Mama/terapia , Estudos de Coortes , Dano ao DNA , Reparo do DNA , Feminino , Humanos , Imunoterapia , Metabolômica , Pessoa de Meia-Idade , Mutagênese/genética , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/metabolismo , Receptor ErbB-2/metabolismo , Proteína do Retinoblastoma/metabolismo , Microambiente Tumoral/imunologiaRESUMO
Mutations in the BRCA1 and BRCA2 genes predispose afflicted individuals to breast, ovarian, and other cancers. The BRCA-encoded products form complexes with other tumor suppressor proteins and with the recombinase enzyme RAD51 to mediate chromosome damage repair by homologous recombination and also to protect stressed DNA replication forks against spurious nucleolytic attrition. Understanding how the BRCA tumor suppressor network executes its biological functions would provide the foundation for developing targeted cancer therapeutics, but progress in this area has been greatly hampered by the challenge of obtaining purified BRCA complexes for mechanistic studies. In this article, we review how recent effort begins to overcome this technical challenge, leading to functional and structural insights into the biochemical attributes of these complexes and the multifaceted roles that they fulfill in genome maintenance. We also highlight the major mechanistic questions that remain.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Redes Reguladoras de Genes , Rad51 Recombinase/genética , Reparo de DNA por Recombinação , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Proteína BRCA1/química , Proteína BRCA1/metabolismo , Proteína BRCA2/química , Proteína BRCA2/metabolismo , Sítios de Ligação , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , DNA/química , DNA/genética , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Replicação do DNA , Feminino , Genoma Humano , Instabilidade Genômica , Humanos , Modelos Moleculares , Ligação Proteica , Estrutura Secundária de Proteína , Rad51 Recombinase/química , Rad51 Recombinase/metabolismo , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Malignancy can be suppressed by the immune system. However, the classes of immunosurveillance responses and their mode of tumor sensing remain incompletely understood. Here, we show that although clear cell renal cell carcinoma (ccRCC) was infiltrated by exhaustion-phenotype CD8+ T cells that negatively correlated with patient prognosis, chromophobe RCC (chRCC) had abundant infiltration of granzyme A-expressing intraepithelial type 1 innate lymphoid cells (ILC1s) that positively associated with patient survival. Interleukin-15 (IL-15) promoted ILC1 granzyme A expression and cytotoxicity, and IL-15 expression in chRCC tumor tissue positively tracked with the ILC1 response. An ILC1 gene signature also predicted survival of a subset of breast cancer patients in association with IL-15 expression. Notably, ILC1s directly interacted with cancer cells, and IL-15 produced by cancer cells supported the expansion and anti-tumor function of ILC1s in a murine breast cancer model. Thus, ILC1 sensing of cancer cell IL-15 defines an immunosurveillance mechanism of epithelial malignancies.
Assuntos
Neoplasias da Mama , Interleucina-15/metabolismo , Animais , Neoplasias da Mama/genética , Linfócitos T CD8-Positivos , Feminino , Granzimas , Humanos , Imunidade Inata , Linfócitos , CamundongosRESUMO
Cancer stem cells (CSCs) are a subpopulation of cancer cells endowed with high tumorigenic, chemoresistant and metastatic potential. Nongenetic mechanisms of acquired resistance are increasingly being discovered, but molecular insights into the evolutionary process of CSCs are limited. Here, we show that type I interferons (IFNs-I) function as molecular hubs of resistance during immunogenic chemotherapy, triggering the epigenetic regulator demethylase 1B (KDM1B) to promote an adaptive, yet reversible, transcriptional rewiring of cancer cells towards stemness and immune escape. Accordingly, KDM1B inhibition prevents the appearance of IFN-I-induced CSCs, both in vitro and in vivo. Notably, IFN-I-induced CSCs are heterogeneous in terms of multidrug resistance, plasticity, invasiveness and immunogenicity. Moreover, in breast cancer (BC) patients receiving anthracycline-based chemotherapy, KDM1B positively correlated with CSC signatures. Our study identifies an IFN-I â KDM1B axis as a potent engine of cancer cell reprogramming, supporting KDM1B targeting as an attractive adjunctive to immunogenic drugs to prevent CSC expansion and increase the long-term benefit of therapy.
Assuntos
Neoplasias da Mama , Epigênese Genética , Histona Desmetilases , Interferon Tipo I , Antraciclinas/metabolismo , Antraciclinas/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Feminino , Histona Desmetilases/metabolismo , Humanos , Interferon Tipo I/metabolismo , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologiaRESUMO
The ability of circulating tumor cells (CTCs) to form clusters has been linked to increased metastatic potential. Yet biological features and vulnerabilities of CTC clusters remain largely unknown. Here, we profile the DNA methylation landscape of single CTCs and CTC clusters from breast cancer patients and mouse models on a genome-wide scale. We find that binding sites for stemness- and proliferation-associated transcription factors are specifically hypomethylated in CTC clusters, including binding sites for OCT4, NANOG, SOX2, and SIN3A, paralleling embryonic stem cell biology. Among 2,486 FDA-approved compounds, we identify Na+/K+ ATPase inhibitors that enable the dissociation of CTC clusters into single cells, leading to DNA methylation remodeling at critical sites and metastasis suppression. Thus, our results link CTC clustering to specific changes in DNA methylation that promote stemness and metastasis and point to cluster-targeting compounds to suppress the spread of cancer.
Assuntos
Neoplasias da Mama/genética , Metástase Neoplásica/genética , Células Neoplásicas Circulantes/patologia , Animais , Neoplasias da Mama/patologia , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Metilação de DNA/fisiologia , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Camundongos Endogâmicos NOD , Proteína Homeobox Nanog/metabolismo , Metástase Neoplásica/fisiopatologia , Células Neoplásicas Circulantes/metabolismo , Fator 3 de Transcrição de Octâmero/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Complexo Correpressor Histona Desacetilase e Sin3RESUMO
Loss of BRCA1 p220 function often results in basal-like breast cancer (BLBC), but the underlying disease mechanism is largely opaque. In mammary epithelial cells (MECs), BRCA1 interacts with multiple proteins, including NUMB and HES1, to form complexes that participate in interstrand crosslink (ICL) DNA repair and MEC differentiation control. Unrepaired ICL damage results in aberrant transdifferentiation to a mesenchymal state of cultured, human basal-like MECs and to a basal/mesenchymal state in primary mouse luminal MECs. Loss of BRCA1, NUMB, or HES1 or chemically induced ICL damage in primary murine luminal MECs results in persistent DNA damage that triggers luminal to basal/mesenchymal transdifferentiation. In vivo single-cell analysis revealed a time-dependent evolution from normal luminal MECs to luminal progenitor-like tumor cells with basal/mesenchymal transdifferentiation during murine BRCA1 BLBC development. Growing DNA damage accompanied this malignant transformation.
Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Transdiferenciação Celular/genética , Dano ao DNA/genética , Reparo do DNA/genética , Glândulas Mamárias Animais/patologia , Animais , Proteína BRCA1/metabolismo , Neoplasias da Mama/induzido quimicamente , Neoplasias da Mama/patologia , Diferenciação Celular/genética , Transformação Celular Neoplásica , Modelos Animais de Doenças , Células Epiteliais/metabolismo , Feminino , Células HEK293 , Humanos , Células MCF-7 , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/metabolismo , Fatores de Transcrição HES-1/metabolismo , TransfecçãoRESUMO
Ductal carcinoma in situ (DCIS) is an early-stage breast cancer that infrequently progresses to invasive ductal carcinoma (IDC). Genomic evolution has been difficult to delineate during invasion due to intratumor heterogeneity and the low number of tumor cells in the ducts. To overcome these challenges, we developed Topographic Single Cell Sequencing (TSCS) to measure genomic copy number profiles of single tumor cells while preserving their spatial context in tissue sections. We applied TSCS to 1,293 single cells from 10 synchronous patients with both DCIS and IDC regions in addition to exome sequencing. Our data reveal a direct genomic lineage between in situ and invasive tumor subpopulations and further show that most mutations and copy number aberrations evolved within the ducts prior to invasion. These results support a multiclonal invasion model, in which one or more clones escape the ducts and migrate into the adjacent tissues to establish the invasive carcinomas.
Assuntos
Neoplasias da Mama/genética , Carcinoma Ductal de Mama/genética , Evolução Clonal , Adulto , Idoso , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Movimento Celular , Exoma , Feminino , Humanos , Pessoa de Meia-Idade , Mutação , Invasividade Neoplásica , Análise de Sequência de DNA , Análise de Célula ÚnicaRESUMO
Breast cancer (BC) comprises multiple distinct subtypes that differ genetically, pathologically, and clinically. Here, we describe a robust protocol for long-term culturing of human mammary epithelial organoids. Using this protocol, >100 primary and metastatic BC organoid lines were generated, broadly recapitulating the diversity of the disease. BC organoid morphologies typically matched the histopathology, hormone receptor status, and HER2 status of the original tumor. DNA copy number variations as well as sequence changes were consistent within tumor-organoid pairs and largely retained even after extended passaging. BC organoids furthermore populated all major gene-expression-based classification groups and allowed in vitro drug screens that were consistent with in vivo xeno-transplantations and patient response. This study describes a representative collection of well-characterized BC organoids available for cancer research and drug development, as well as a strategy to assess in vitro drug response in a personalized fashion.
Assuntos
Neoplasias da Mama/patologia , Heterogeneidade Genética , Organoides/patologia , Bancos de Tecidos , Animais , Antineoplásicos/farmacologia , Neoplasias da Mama/genética , Células Cultivadas , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Feminino , Humanos , Camundongos , Camundongos Nus , Organoides/efeitos dos fármacos , Medicina de Precisão/métodosRESUMO
Noncoding mutations in cancer genomes are frequent but challenging to interpret. PVT1 encodes an oncogenic lncRNA, but recurrent translocations and deletions in human cancers suggest alternative mechanisms. Here, we show that the PVT1 promoter has a tumor-suppressor function that is independent of PVT1 lncRNA. CRISPR interference of PVT1 promoter enhances breast cancer cell competition and growth in vivo. The promoters of the PVT1 and the MYC oncogenes, located 55 kb apart on chromosome 8q24, compete for engagement with four intragenic enhancers in the PVT1 locus, thereby allowing the PVT1 promoter to regulate pause release of MYC transcription. PVT1 undergoes developmentally regulated monoallelic expression, and the PVT1 promoter inhibits MYC expression only from the same chromosome via promoter competition. Cancer genome sequencing identifies recurrent mutations encompassing the human PVT1 promoter, and genome editing verified that PVT1 promoter mutation promotes cancer cell growth. These results highlight regulatory sequences of lncRNA genes as potential disease-associated DNA elements.
Assuntos
Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica , Genes myc , RNA Longo não Codificante/genética , Animais , Neoplasias da Mama/metabolismo , Sistemas CRISPR-Cas , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células , Transformação Celular Neoplásica , Cromatina , DNA de Neoplasias/genética , Elementos Facilitadores Genéticos , Feminino , Perfilação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Mutação , Transplante de Neoplasias , Regiões Promotoras Genéticas , RNA Longo não Codificante/metabolismo , Transcrição GênicaRESUMO
Autophagy supports both cellular and organismal homeostasis. However, whether autophagy should be inhibited or activated for cancer therapy remains unclear. Deletion of essential autophagy genes increased the sensitivity of mouse mammary carcinoma cells to radiation therapy in vitro and in vivo (in immunocompetent syngeneic hosts). Autophagy-deficient cells secreted increased amounts of type I interferon (IFN), which could be limited by CGAS or STING knockdown, mitochondrial DNA depletion or mitochondrial outer membrane permeabilization blockage via BCL2 overexpression or BAX deletion. In vivo, irradiated autophagy-incompetent mammary tumors elicited robust immunity, leading to improved control of distant nonirradiated lesions via systemic type I IFN signaling. Finally, a genetic signature of autophagy had negative prognostic value in patients with breast cancer, inversely correlating with mitochondrial abundance, type I IFN signaling and effector immunity. As clinically useful autophagy inhibitors are elusive, our findings suggest that mitochondrial outer membrane permeabilization may represent a valid target for boosting radiation therapy immunogenicity in patients with breast cancer.
Assuntos
Proteína 5 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/genética , Autofagia/genética , Neoplasias da Mama/radioterapia , DNA Mitocondrial/genética , Neoplasias Mamárias Animais/radioterapia , Mitocôndrias/metabolismo , Adulto , Idoso , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Linhagem Celular Tumoral , Citotoxicidade Imunológica , Feminino , Humanos , Interferon Tipo I/metabolismo , Neoplasias Mamárias Animais/genética , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Prognóstico , Tolerância a Radiação , Transdução de Sinais , Análise de SobrevidaRESUMO
The tumour suppressor breast cancer type 1 susceptibility protein (BRCA1) promotes DNA double-strand break (DSB) repair by homologous recombination and protects DNA replication forks from attrition. BRCA1 partners with BRCA1-associated RING domain protein 1 (BARD1) and other tumour suppressor proteins to mediate the initial nucleolytic resection of DNA lesions and the recruitment and regulation of the recombinase RAD51. The discovery of the opposing functions of BRCA1 and the p53-binding protein 1 (53BP1)-associated complex in DNA resection sheds light on how BRCA1 influences the choice of homologous recombination over non-homologous end joining and potentially other mutagenic pathways of DSB repair. Understanding the functional crosstalk between BRCA1-BARD1 and its cofactors and antagonists will illuminate the molecular basis of cancers that arise from a deficiency or misregulation of chromosome damage repair and replication fork maintenance. Such knowledge will also be valuable for understanding acquired tumour resistance to poly(ADP-ribose) polymerase (PARP) inhibitors and other therapeutics and for the development of new treatments. In this Review, we discuss recent advances in elucidating the mechanisms by which BRCA1-BARD1 functions in DNA repair, replication fork maintenance and tumour suppression, and its therapeutic relevance.
Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Proteínas Supressoras de Tumor/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Ubiquitina-Proteína Ligases/genética , Neoplasias da Mama/patologia , Reparo do DNA por Junção de Extremidades/genética , Replicação do DNA/genética , Feminino , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/genética , Ligação Proteica/genética , Reparo de DNA por Recombinação/genéticaRESUMO
Humans with inherited heterozygous BRCA2 mutations have an increased risk of developing cancer; however, what triggers carcinogenesis in these individuals is unclear. Tan et al. find that environmental and metabolic aldehydes pose a threat to these individuals by promoting degradation of wild-type BRCA2 protein, thereby predisposing them to genomic instability and perhaps to cancer.
Assuntos
Aldeídos , Mutação , Proteína BRCA2/genética , Neoplasias da Mama/genética , Genes BRCA1 , Instabilidade Genômica , Mutação em Linhagem Germinativa , Heterozigoto , HumanosRESUMO
Transfer RNAs (tRNAs) are primarily viewed as static contributors to gene expression. By developing a high-throughput tRNA profiling method, we find that specific tRNAs are upregulated in human breast cancer cells as they gain metastatic activity. Through loss-of-function, gain-of-function, and clinical-association studies, we implicate tRNAGluUUC and tRNAArgCCG as promoters of breast cancer metastasis. Upregulation of these tRNAs enhances stability and ribosome occupancy of transcripts enriched for their cognate codons. Specifically, tRNAGluUUC promotes metastatic progression by directly enhancing EXOSC2 expression and enhancing GRIPAP1-constituting an "inducible" pathway driven by a tRNA. The cellular proteomic shift toward a pro-metastatic state mirrors global tRNA shifts, allowing for cell-state and cell-type transgene expression optimization through codon content quantification. TRNA modulation represents a mechanism by which cells achieve altered expression of specific transcripts and proteins. TRNAs are thus dynamic regulators of gene expression and the tRNA codon landscape can causally and specifically impact disease progression.
Assuntos
Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica , RNA de Transferência/metabolismo , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Códon , Progressão da Doença , Complexo Multienzimático de Ribonucleases do Exossomo/genética , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Pulmão/patologia , Camundongos , Invasividade Neoplásica/genética , Micrometástase de Neoplasia/genética , Proteínas de Neoplasias/biossíntese , Proteínas de Ligação a RNA/genética , Sequências Reguladoras de Ácido Ribonucleico , Ribossomos/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Large-scale genomic studies have identified multiple somatic aberrations in breast cancer, including copy number alterations and point mutations. Still, identifying causal variants and emergent vulnerabilities that arise as a consequence of genetic alterations remain major challenges. We performed whole-genome small hairpin RNA (shRNA) "dropout screens" on 77 breast cancer cell lines. Using a hierarchical linear regression algorithm to score our screen results and integrate them with accompanying detailed genetic and proteomic information, we identify vulnerabilities in breast cancer, including candidate "drivers," and reveal general functional genomic properties of cancer cells. Comparisons of gene essentiality with drug sensitivity data suggest potential resistance mechanisms, effects of existing anti-cancer drugs, and opportunities for combination therapy. Finally, we demonstrate the utility of this large dataset by identifying BRD4 as a potential target in luminal breast cancer and PIK3CA mutations as a resistance determinant for BET-inhibitors.
Assuntos
Algoritmos , Neoplasias da Mama/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Classe I de Fosfatidilinositol 3-Quinases , Análise por Conglomerados , Resistencia a Medicamentos Antineoplásicos , Dosagem de Genes , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Humanos , Modelos Lineares , Proteínas Nucleares/genética , Fosfatidilinositol 3-Quinases , Fatores de Transcrição/genéticaRESUMO
The inter- and intra-tumor heterogeneity of breast cancer needs to be adequately captured in pre-clinical models. We have created a large collection of breast cancer patient-derived tumor xenografts (PDTXs), in which the morphological and molecular characteristics of the originating tumor are preserved through passaging in the mouse. An integrated platform combining in vivo maintenance of these PDTXs along with short-term cultures of PDTX-derived tumor cells (PDTCs) was optimized. Remarkably, the intra-tumor genomic clonal architecture present in the originating breast cancers was mostly preserved upon serial passaging in xenografts and in short-term cultured PDTCs. We assessed drug responses in PDTCs on a high-throughput platform and validated several ex vivo responses in vivo. The biobank represents a powerful resource for pre-clinical breast cancer pharmacogenomic studies (http://caldaslab.cruk.cam.ac.uk/bcape), including identification of biomarkers of response or resistance.