RESUMEN
In diffuse large B-cell lymphoma (DLBCL), activation of the B-cell receptor (BCR) promotes multiple oncogenic signals, which are essential for tumor proliferation. Inhibition of the Bruton's tyrosine kinase (BTK), a BCR downstream target, is therapeutically effective only in a subgroup of patients with DLBCL. Here, we used lymphoma cells isolated from patients with DLBCL to measure the effects of targeted therapies on BCR signaling and to anticipate response. In lymphomas resistant to BTK inhibition, we show that blocking BTK activity enhanced tumor dependencies from alternative oncogenic signals downstream of the BCR, converging on MYC upregulation. To completely ablate the activity of the BCR, we genetically and pharmacologically repressed the activity of the SRC kinases LYN, FYN, and BLK, which are responsible for the propagation of the BCR signal. Inhibition of these kinases strongly reduced tumor growth in xenografts and cell lines derived from patients with DLBCL independent of their molecular subtype, advancing the possibility to be relevant therapeutic targets in broad and diverse groups of DLBCL patients.
Asunto(s)
Linfoma no Hodgkin/etiología , Linfoma no Hodgkin/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Receptores de Antígenos de Linfocitos B/metabolismo , Transducción de Señal/efectos de los fármacos , Familia-src Quinasas/antagonistas & inhibidores , Adenina/análogos & derivados , Animales , Línea Celular Tumoral , Transformación Celular Neoplásica/metabolismo , Modelos Animales de Enfermedad , Resistencia a Antineoplásicos/genética , Expresión Génica , Genes myc , Humanos , Linfoma no Hodgkin/tratamiento farmacológico , Linfoma no Hodgkin/patología , Ratones , Ratones Noqueados , Piperidinas , Pirazoles/farmacología , Pirimidinas/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Molecular drivers underlying bone metastases in human cancer are not well understood, in part due to constraints in bone tissue sampling. Here, RNA sequencing was performed of circulating tumor cells (CTC) isolated from blood samples of women with metastatic estrogen receptor (ER)+ breast cancer, comparing cases with progression in bone versus visceral organs. Among the activated cellular pathways in CTCs from bone-predominant breast cancer is androgen receptor (AR) signaling. AR gene expression is evident, as is its constitutively active splice variant AR-v7. AR expression within CTCs is correlated with the duration of treatment with aromatase inhibitors, suggesting that it contributes to acquired resistance to endocrine therapy. In an established breast cancer xenograft model, a bone-tropic derivative displays increased AR expression, whose genetic or pharmacologic suppression reduces metastases to bone but not to lungs. Together, these observations identify AR signaling in CTCs from women with bone-predominant ER+ breast cancer, and provide a rationale for testing androgen inhibitors in this subset of patients.Implications: This study highlights a role for the AR in breast cancer bone metastasis, and suggests that therapeutic targeting of the AR may benefit patients with metastatic breast cancer. Mol Cancer Res; 16(4); 720-7. ©2018 AACR.
Asunto(s)
Neoplasias Óseas/secundario , Neoplasias de la Mama/genética , Células Neoplásicas Circulantes/química , Receptores Androgénicos/genética , Neoplasias Abdominales/secundario , Empalme Alternativo , Animales , Antineoplásicos Hormonales/uso terapéutico , Biomarcadores de Tumor/genética , Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/genética , Neoplasias de la Mama/tratamiento farmacológico , Resistencia a Antineoplásicos , Femenino , Humanos , Ratones , Análisis de Secuencia de ARN , Análisis de la Célula IndividualRESUMEN
SESTRIN1 is a tumor suppressor in follicular lymphoma that controls mTORC1 activity and it is inactivated by chromosomal deletions or epigenetically silenced by mutant EZH2Y641X. Pharmacological inhibition of EZH2 promotes SESTRIN1 re-expression and it restores its tumor suppressive activity, suggesting the possibility to epigenetically control mTORC1 activity.
RESUMEN
Cancer cells metastasize through the bloodstream either as single migratory circulating tumor cells (CTCs) or as multicellular groupings (CTC clusters). Existing technologies for CTC enrichment are designed to isolate single CTCs, and although CTC clusters are detectable in some cases, their true prevalence and significance remain to be determined. Here we developed a microchip technology (the Cluster-Chip) to capture CTC clusters independently of tumor-specific markers from unprocessed blood. CTC clusters are isolated through specialized bifurcating traps under low-shear stress conditions that preserve their integrity, and even two-cell clusters are captured efficiently. Using the Cluster-Chip, we identified CTC clusters in 30-40% of patients with metastatic breast or prostate cancer or with melanoma. RNA sequencing of CTC clusters confirmed their tumor origin and identified tissue-derived macrophages within the clusters. Efficient capture of CTC clusters will enable the detailed characterization of their biological properties and role in metastasis.
Asunto(s)
Técnicas Analíticas Microfluídicas , Células Neoplásicas Circulantes , Neoplasias de la Mama/patología , Línea Celular Tumoral , Femenino , Humanos , Inmunohistoquímica , Masculino , Neoplasias de la Próstata/patología , Análisis de Secuencia de ARNRESUMEN
Circulating tumor cell clusters (CTC clusters) are present in the blood of patients with cancer but their contribution to metastasis is not well defined. Using mouse models with tagged mammary tumors, we demonstrate that CTC clusters arise from oligoclonal tumor cell groupings and not from intravascular aggregation events. Although rare in the circulation compared with single CTCs, CTC clusters have 23- to 50-fold increased metastatic potential. In patients with breast cancer, single-cell resolution RNA sequencing of CTC clusters and single CTCs, matched within individual blood samples, identifies the cell junction component plakoglobin as highly differentially expressed. In mouse models, knockdown of plakoglobin abrogates CTC cluster formation and suppresses lung metastases. In breast cancer patients, both abundance of CTC clusters and high tumor plakoglobin levels denote adverse outcomes. Thus, CTC clusters are derived from multicellular groupings of primary tumor cells held together through plakoglobin-dependent intercellular adhesion, and though rare, they greatly contribute to the metastatic spread of cancer.
Asunto(s)
Neoplasias de la Mama/patología , Metástasis de la Neoplasia/patología , Células Neoplásicas Circulantes/patología , Animales , Neoplasias de la Mama/fisiopatología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/fisiopatología , Análisis de Secuencia de ARN , Análisis de la Célula Individual , gamma Catenina/metabolismoRESUMEN
Circulating tumor cells (CTCs) are present at low concentrations in the peripheral blood of patients with solid tumors. It has been proposed that the isolation, ex vivo culture, and characterization of CTCs may provide an opportunity to noninvasively monitor the changing patterns of drug susceptibility in individual patients as their tumors acquire new mutations. In a proof-of-concept study, we established CTC cultures from six patients with estrogen receptor-positive breast cancer. Three of five CTC lines tested were tumorigenic in mice. Genome sequencing of the CTC lines revealed preexisting mutations in the PIK3CA gene and newly acquired mutations in the estrogen receptor gene (ESR1), PIK3CA gene, and fibroblast growth factor receptor gene (FGFR2), among others. Drug sensitivity testing of CTC lines with multiple mutations revealed potential new therapeutic targets. With optimization of CTC culture conditions, this strategy may help identify the best therapies for individual cancer patients over the course of their disease.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Resistencia a Antineoplásicos/genética , Terapia Molecular Dirigida , Células Neoplásicas Circulantes/efectos de los fármacos , Animales , Antineoplásicos/uso terapéutico , Neoplasias de la Mama/genética , Técnicas de Cultivo de Célula , Separación Celular , Fosfatidilinositol 3-Quinasa Clase I , Cultura , Ensayos de Selección de Medicamentos Antitumorales/métodos , Receptor alfa de Estrógeno/genética , Femenino , Frecuencia de los Genes , Humanos , Ratones , Microfluídica/métodos , Mutación , Células Neoplásicas Circulantes/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Análisis de Secuencia de ADN , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Epithelial-mesenchymal transition (EMT) of adherent epithelial cells to a migratory mesenchymal state has been implicated in tumor metastasis in preclinical models. To investigate its role in human cancer, we characterized EMT in circulating tumor cells (CTCs) from breast cancer patients. Rare primary tumor cells simultaneously expressed mesenchymal and epithelial markers, but mesenchymal cells were highly enriched in CTCs. Serial CTC monitoring in 11 patients suggested an association of mesenchymal CTCs with disease progression. In an index patient, reversible shifts between these cell fates accompanied each cycle of response to therapy and disease progression. Mesenchymal CTCs occurred as both single cells and multicellular clusters, expressing known EMT regulators, including transforming growth factor (TGF)-ß pathway components and the FOXC1 transcription factor. These data support a role for EMT in the blood-borne dissemination of human breast cancer.