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Rationale: Triple-negative breast cancer (TNBC) does not respond to anti-estrogen and anti-HER2 therapies and is commonly treated by chemotherapy. TNBC has a high recurrence rate, particularly within the first 3 years. Thus, there is an urgent clinical need to develop more effective therapies for TNBC. Topoisomerase I (TOP1) inhibitors cause DNA damage, making these drugs desirable for TNBC treatment since DNA repair machinery is defective in this subtype of breast cancer. Among the main molecular subtypes of breast cancer, the TNBC cell lines exhibited the highest TOP1 inhibition sensitivity. However, clinically used TOP1 inhibitors, such as topotecan and irinotecan, have shown limited clinical applications and the reasons remain unclear. Understanding the mechanism of differential responses to TOP1 blockade and identifying the predictive markers for cancer cell sensitivity will help further TOP1-targeted therapy for TNBC treatment and improve the clinical use of TOP1 inhibitors. Methods: Viability assays were used to evaluate breast cancer cell sensitivity to topotecan and other TOP1 inhibitors as well as TOP2 inhibitors. An in vitro-derived topotecan-resistant TNBC cell model and TNBC xenograft models were employed to confirm cancer cell response to TOP1 blockade. RNA-seq was used to identify potential predictive markers for TNBC cell response to TOP1 blockade. Western blotting and qRT-PCR were performed to measure the protein levels and RNA expression. ATAC-seq and luciferase reporter assays were used to examine MYC transcriptional regulations. The effects of MYC and JNK in cancer cell response to TOP1 inhibition were validated via loss-of-function and gain-of-function experiments. Results: We observed two distinct and diverging cancer cell responses - sensitive versus resistant to TOP1 inhibition, which was confirmed by TNBC xenograft mouse models treated by topotecan. TNBC cells exhibited bifurcated temporal patterns of ATR pathway activation upon TOP1 inhibitor treatment. The sensitive TNBC cells showed an "up then down" dynamic pattern of ATR/Chk1 signaling, while the resistant TNBC cells exhibited a "persistently up" profile. On the contrary, opposite temporal patterns of induced expression of MYC, a key regulator and effector of DNA damage, were found in TNBC cells treated by TOP1 inhibitors. Mechanistically, we showed that TOP1-induced JNK signaling upregulated MYC expression. Furthermore, pharmacological inhibition of ATR reversed TNBC cell resistance to topotecan, whereas MYC knockdown and JNK inhibition reduced cancer cell sensitivity. Conclusions: Dynamic temporal profiles of induced ATR/Chk1 and JNK activation as well as MYC expression, may predict cancer cell response to TOP1 inhibitors. JNK activation-mediated constitutive elevation of MYC expression may represent a novel mechanism governing cancer cell sensitivity to TOP1-targeting therapy. Our results may provide implications for identifying TNBC patients who might benefit from the treatment with TOP1 inhibitors.
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DNA Topoisomerases Tipo I , Neoplasias de Mama Triplo Negativas , Animais , Linhagem Celular Tumoral , Proliferação de Células , DNA Topoisomerases Tipo I/metabolismo , DNA Topoisomerases Tipo I/farmacologia , DNA Topoisomerases Tipo I/uso terapêutico , Humanos , Camundongos , Proteínas Proto-Oncogênicas c-myc/genética , Transdução de Sinais/genética , Topotecan/farmacologia , Topotecan/uso terapêutico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismoRESUMO
Carbon dots (CDs) have attracted much attention in theoretical researches and their practical applications due to their excellent optical properties, and many researchers discovered that flurophores play a very important role in synthesis process of CDs and the luminescence of prepared CDs. In this study, two CDs were pyrolysis with citric acid, N-acetyl-l-cysteine and glutathione derivatives as carbon sources. Four intermediate small molecules were separated from the prepared CDs through ultrafiltration and chromatography, and their chemical structures were determined. The formation process of CDs was monitored through identified small molecule intermediates and HPLC. It is speculated that the two CDs have the same formation pathway, including TPA (5-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyridine-3,7-dicarboxylic acid) synthesis, fluorophore polymerization, carbon chain extension, and carbonization. It was also discovered that these two CDs have the same fluorescence properties, thiazolopyridone structure, and nitrogen-sulfur co-doped functional groups are important reasons for the mixed excitation dependence of CDs. This study would provide valuable theoretical basis for the studies on preparation of excellent CDs, raw material selection, and CDs formation mechanism.
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Triple-negative breast cancer (TNBC) has a high propensity for organ-specific metastasis. However, the underlying mechanisms are not well understood. Here we show that the primary TNBC tumor-derived C-X-C motif chemokines 1/2/8 (CXCL1/2/8) stimulate lung-resident fibroblasts to produce the C-C motif chemokines 2/7 (CCL2/7), which, in turn, activate cholesterol synthesis in lung-colonizing TNBC cells and induce angiogenesis at lung metastatic sites. Inhibiting cholesterol synthesis in lung-colonizing breast tumor cells by pulmonary administration of simvastatin-carrying HER3-targeting nanoparticles reduces angiogenesis and growth of lung metastases in a syngeneic TNBC mouse model. Our findings reveal a novel, chemokine-regulated mechanism for the cholesterol synthesis pathway and a critical role of metastatic site-specific cholesterol synthesis in the pulmonary tropism of TNBC metastasis. The study has implications for the unresolved epidemiological observation that use of cholesterol-lowering drugs has no effect on breast cancer incidence but can unexpectedly reduce breast cancer mortality, suggesting interventions of cholesterol synthesis in lung metastases as an effective treatment to improve survival in individuals with TNBC.
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Neoplasias de Mama Triplo Negativas , Animais , Linhagem Celular Tumoral , Quimiocinas , Humanos , Pulmão/metabolismo , Camundongos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/genética , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
Triple-negative breast cancer (TNBC) is associated with a high rate of early recurrence and distant metastasis, frequent development of therapeutic resistance, and a poor prognosis. There is a lack of targeted therapies for this aggressive subtype of breast cancer. Identifying novel effective treatment modalities for TNBC remains an urgent and unmet clinical need. In this study, we investigated the anti-cancer effect of triptonide, a natural compound derived from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, in TNBC. We found that triptonide inhibits human TNBC cell growth in vitro and growth of TNBC xenograft mammary tumors. It induces apoptosis and suppresses stem-like properties as indicated by reduced mammosphere formation and aldehyde dehydrogenase activity in TNBC cells. We show that triptonide downregulates multiple cancer stem cell-associated genes but upregulates SNAI1 gene expression. In support of SNAI1 induction as a negative feedback response to triptonide treatment, in vitro-derived triptonide-resistant HCC1806 cells display a markedly higher expression of SNAI1 compared with parental cells. Mechanistically, the increase of SNAI1 expression is mediated by the activation of JNK signaling, but not by ERK and AKT, two well-established SNAI1 regulators. Furthermore, knockdown of SNAI1 in the triptonide-resistant HCC1806 cells increases sensitivity to triptonide and reduces mammosphere formation. These results indicate that triptonide holds promise as a novel anti-tumor agent for TNBC treatment. Our study also reveals a SNAI1-associated feedback mechanism which may lead to acquired resistance to triptonide.
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Antineoplásicos Fitogênicos/farmacologia , Descoberta de Drogas , Triterpenos/farmacologia , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Estrutura Molecular , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Triterpenos/química , Triterpenos/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cyclin Dependent Kinase 9 (CDK9) associates with Bromodomain and Extra-Terminal Domain (BET) proteins to promote transcriptional elongation by phosphorylation of serine 2 of RNAP II C-terminal domain. We examined the therapeutic potential of selective CDK9 inhibitors (AZD 4573 and MC180295) against human multiple myeloma cells in vitro. Short-hairpin RNA silencing of CDK9 in Multiple Myeloma (MM) cell lines reduced cell viability compared to control cells showing the dependency of MM cells on CDK9. In order to explore synergy with the CDK9 inhibitor, proteolysis targeting chimeric molecule (PROTAC) ARV 825 was added. This latter drug causes ubiquitination of BET proteins resulting in their rapid and efficient degradation. Combination treatment of MM cells with ARV 825 and AZD 4573 markedly reduced their protein expression of BRD 2, BRD 4, MYC and phosphorylated RNA pol II as compared to each single agent alone. Combination treatment synergistically inhibited multiple myeloma cells both in vitro and in vivo with insignificant weight loss. The combination also resulted in marked increase of apoptotic cells at low dose compared to single agent alone. Taken together, our studies show for the first time that the combination of a BET PROTAC (ARV 825) plus AZD 4573 (CDK9 inhibitor) is effective against MM cells.
Assuntos
Quinase 9 Dependente de Ciclina/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas/metabolismo , Proteólise/efeitos dos fármacos , Animais , Azepinas/farmacologia , Azepinas/uso terapêutico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 9 Dependente de Ciclina/genética , Quinase 9 Dependente de Ciclina/metabolismo , Regulação para Baixo/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Camundongos , Camundongos SCID , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/patologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Interferência de RNA , RNA Polimerase II/metabolismo , RNA Interferente Pequeno/metabolismo , Talidomida/análogos & derivados , Talidomida/farmacologia , Talidomida/uso terapêutico , Transplante HeterólogoRESUMO
PURPOSE: Conditional reprogramming methods allow for the inexhaustible in vitro proliferation of primary epithelial cells from human tissue specimens. This methodology has the potential to enhance the utility of primary cell culture as a model for mammary gland research. However, few studies have systematically characterized this method in generating in vitro normal human mammary epithelial cell models. RESULTS: We show that cells derived from fresh normal breast tissues can be propagated and exhibit heterogeneous morphologic features. The cultures are composed of CK18, desmoglein 3, and CK19-positive luminal cells and vimentin, p63, and CK14-positive myoepithelial cells, suggesting the maintenance of in vivo heterogeneity. In addition, the cultures contain subpopulations with different CD49f and EpCAM expression profiles. When grown in 3D conditions, cells self-organize into distinct structures that express either luminal or basal cell markers. Among these structures, CK8-positive cells enclosing a lumen are capable of differentiation into milk-producing cells in the presence of lactogenic stimulus. Furthermore, our short-term cultures retain the expression of ERα, as well as its ability to respond to estrogen stimulation. MATERIALS AND METHODS: We have investigated conditionally reprogrammed normal epithelial cells in terms of cell type heterogeneity, cellular marker expression, and structural arrangement in two-dimensional (2D) and three-dimensional (3D) systems. CONCLUSIONS: The conditional reprogramming methodology allows generation of a heterogeneous culture from normal human mammary tissue in vitro. We believe that this cell culture model will provide a valuable tool to study mammary cell function and malignant transformation.
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Distant metastasis accounts for the vast majority of deaths in patients with cancer. Breast cancer exhibits a distinct metastatic pattern commonly involving bone, liver, lung, and brain. Breast cancer can be divided into different subtypes based on gene expression profiles, and different breast cancer subtypes show preference to distinct organ sites of metastasis. Luminal breast tumors tend to metastasize to bone while basal-like breast cancer (BLBC) displays a lung tropism of metastasis. However, the mechanisms underlying this organ-specific pattern of metastasis still remain to be elucidated. In this review, we will summarize the recent advances regarding the molecular signaling pathways as well as the therapeutic strategies for treating breast cancer lung metastasis.
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Neoplasias da Mama/patologia , Neoplasias Pulmonares/secundário , Biomarcadores , Neoplasias da Mama/etiologia , Neoplasias da Mama/metabolismo , Citocinas/metabolismo , Feminino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , Gradação de Tumores , Estadiamento de Neoplasias , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Transdução de Sinais , Microambiente TumoralRESUMO
Triple-negative breast cancer (TNBC) has high rates of local recurrence and distant metastasis, partially due to its high invasiveness. The Forkhead box C1 (FOXC1) transcription factor has been shown to be specifically overexpressed in TNBC and associated with poor clinical outcome. How TNBC's high invasiveness is driven by FOXC1 and its downstream targets remains poorly understood. In the present study, pathway-specific PCR array assays revealed that WNT5A and matrix metalloproteinase-7 (MMP7) were upregulated by FOXC1 in TNBC cells. Interestingly, WNT5A mediates the upregulation of MMP7 by FOXC1 and the WNT5A-MMP7 axis is essential for FOXC1-induced invasiveness of TNBC cells in vitro. Xenograft models showed that the lung extravasation and metastasis of FOXC1-overexpressing TNBC cells were attenuated by knocking out WNT5A, but could be restored by MMP7 overexpression. Mechanistically, FOXC1 can bind directly to the WNT5A promoter region to activate its expression. Engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP), coupled with mass spectrometry, identified FOXC1-interacting proteins including a group of heterogeneous nuclear ribonucleoproteins involved in WNT5A transcription induction. Finally, we found that WNT5A activates NF-κB signaling to induce MMP7 expression. Collectively, these data demonstrate a FOXC1-elicited non-canonical WNT5A signaling mechanism comprising NF-κB and MMP7 that is essential for TNBC cell invasiveness, thereby providing implications toward developing an effective therapy for TNBC.
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Fatores de Transcrição Forkhead/fisiologia , Metaloproteinase 7 da Matriz/genética , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Proteína Wnt-5a/genética , Animais , Linhagem Celular Tumoral , Feminino , Fatores de Transcrição Forkhead/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Metaloproteinase 7 da Matriz/metabolismo , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transdução de Sinais/genética , Ativação Transcricional , Proteína Wnt-5a/metabolismoRESUMO
Resistance to anti-tumor therapeutics is an important clinical problem. Tumor-targeted therapies currently used in the clinic are derived from antibodies or small molecules that mitigate growth factor activity. These have improved therapeutic efficacy and safety compared to traditional treatment modalities but resistance arises in the majority of clinical cases. Targeting such resistance could improve tumor abatement and patient survival. A growing number of such tumors are characterized by prominent expression of the human epidermal growth factor receptor 3 (HER3) on the cell surface. This study presents a "Trojan-Horse" approach to combating these tumors by using a receptor-targeted biocarrier that exploits the HER3 cell surface protein as a portal to sneak therapeutics into tumor cells by mimicking an essential ligand. The biocarrier used here combines several functions within a single fusion protein for mediating targeted cell penetration and non-covalent self-assembly with therapeutic cargo, forming HER3-homing nanobiologics. Importantly, we demonstrate here that these nanobiologics are therapeutically effective in several scenarios of resistance to clinically approved targeted inhibitors of the human EGF receptor family. We also show that such inhibitors heighten efficacy of our nanobiologics on naïve tumors by augmenting HER3 expression. This approach takes advantage of a current clinical problem (i.e. resistance to growth factor inhibition) and uses it to make tumors more susceptible to HER3 nanobiologic treatment. Moreover, we demonstrate a novel approach in addressing drug resistance by taking inhibitors against which resistance arises and re-introducing these as adjuvants, sensitizing tumors to the HER3 nanobiologics described here.
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Antineoplásicos/administração & dosagem , Produtos Biológicos/administração & dosagem , Portadores de Fármacos/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Nanopartículas/administração & dosagem , Peptídeos/administração & dosagem , Receptor ErbB-3/metabolismo , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Camundongos , Neoplasias/tratamento farmacológicoRESUMO
The forkhead box transcription factor FOXC1 plays a critical role in embryogenesis and the development of many organs. Its mutations and high expression are associated with many human diseases including breast cancer. Although FOXC1 knockout mouse studies showed that it is not required for mammary gland development during puberty, it is not clear whether its overexpression alters normal mammary development in vivo. To address this question, we generated transgenic mice with mammary-specific FOXC1 overexpression. We report that transgenic FOXC1 overexpression suppresses lobuloalveologenesis and lactation in mice. This phenotype is associated with higher percentages of estrogen receptor-, progesterone receptor-, or ki67-positive mammary epithelial cells in the transgenic mice at the lactation stage. We also show that expression of the Elf5 transcription factor, a master regulator of mammary alveologenesis and luminal cell differentiation, is markedly reduced in mammary epithelial cells of transgenic mice. Likewise, levels of activated Stat5, another inducer of alveolar expansion and a known mediator of the Elf5 effect, are also lowered in those cells. In contrast, the cytokeratin 8-positive mammary cell population with progenitor properties is elevated in the transgenic mice at the lactation stage, suggesting inhibition of mammary cell differentiation. These results may implicate FOXC1 as a new important regulator of mammary gland development.
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Fatores de Transcrição Forkhead/fisiologia , Glândulas Mamárias Animais/metabolismo , Animais , Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Células Epiteliais/metabolismo , Feminino , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Queratina-8/metabolismo , Antígeno Ki-67/metabolismo , Glândulas Mamárias Animais/crescimento & desenvolvimento , Glândulas Mamárias Animais/fisiologia , Camundongos , Camundongos Transgênicos , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Fator de Transcrição STAT5/metabolismo , Fatores de Transcrição/metabolismoRESUMO
BACKGROUND: The pathogenesis of human basal-like breast cancer (BLBC) is not well understood and patients with BLBC have a poor prognosis. Expression of the epidermal growth factor receptor (EGFR) and nuclear factor-κB (NF-κB) is well-known to be upregulated in BLBC. The forkhead box C1 (FOXC1) transcription factor, an important prognostic biomarker specific for BLBC, has been shown to be induced by EGF and is critical for EGF effects in breast cancer cells. How FOXC1 is transcriptionally activated in BLBC is not clear. METHODS: Luciferase reporter assays were performed to show that NF-κB-p65 enhances FOXC1 promoter activity in BLBC cells (MDA-MB-468). Electrophoretic mobility shift assay, biotinylated oligonucleotide precipitation assay, and chromatin immunoprecipitation assay were used to show that NF-κB interacts and binds to the promoter region of FOXC1. RESULTS: In this study, we demonstrate that NF-κB is a pivotal mediator of the EGF/EGFR regulation of FOXC1 expression by binding to the FOXC1 promoter to activate FOXC1 transcription. Loss or inhibition of NF-κB diminished FOXC1 expression. CONCLUSION: Collectively, our findings reveal a novel EGFR-NF-κB-FOXC1 signaling axis that is critical for BLBC cell function, supporting the notion that intervention in the FOXC1 pathway may provide potential modalities for BLBC treatment.
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Neoplasias da Mama/patologia , Fator de Crescimento Epidérmico/metabolismo , Fatores de Transcrição Forkhead/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais , Sequência de Bases , Linhagem Celular Tumoral , Fatores de Transcrição Forkhead/genética , Humanos , Regiões Promotoras Genéticas/genéticaRESUMO
Human induced pluripotent stem cells (iPSCs) can give rise to multiple cell types and hold great promise in regenerative medicine and disease-modeling applications. We have developed a reliable two-step protocol to generate human mammary-like organoids from iPSCs. Non-neural ectoderm-cell-containing spheres, referred to as mEBs, were first differentiated and enriched from iPSCs using MammoCult medium. Gene expression profile analysis suggested that mammary gland function-associated signaling pathways were hallmarks of 10-day differentiated mEBs. We then generated mammary-like organoids from 10-day mEBs using 3D floating mixed gel culture and a three-stage differentiation procedure. These organoids expressed common breast tissue, luminal, and basal markers, including estrogen receptor, and could be induced to produce milk protein. These results demonstrate that human iPSCs can be directed in vitro toward mammary lineage differentiation. Our findings provide an iPSC-based model for studying regulation of normal mammary cell fate and function as well as breast disease development.
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Diferenciação Celular , Células-Tronco Pluripotentes Induzidas/citologia , Organoides , Biomarcadores , Técnicas de Cultura de Células , Diferenciação Celular/genética , Ectoderma/citologia , Ectoderma/embriologia , Corpos Embrioides/citologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Imuno-Histoquímica , Células-Tronco Pluripotentes Induzidas/metabolismo , Organoides/citologia , Medicina Regenerativa , TranscriptomaRESUMO
Breast cancers arising in the setting of the hereditary breast cancer genes BRCA1 and BRCA2 are most commonly classified as basal-like breast cancer (BLBC) or luminal breast cancer, respectively. BLBC is an aggressive subtype of breast cancer associated with liver and lung metastases and poorer prognosis than other subtypes and for which chemotherapy is the only systemic therapy. Multiple immunohistochemical markers are used to identify the basal-like subtype, including the absence of estrogen receptor alpha, progesterone receptor, and human epidermal growth factor receptor 2. Forkhead box C1 (FOXC1) has been identified as a specific marker expressed in BLBC in general breast cancer cohorts. We examined an institutional cohort of breast cancer patients with germline BRCA1 (n=46) and BRCA2 (n=35) mutations and found that FOXC1 expression on immunohistochemical staining is associated with BRCA1 vs BRCA2 mutations [30/46 vs. 6/35]. In BRCA1 mutant tumors, FOXC1 was expressed in 28/31 BLBC tumors and 2/13 non-BLBC tumors, In BRCA2 mutant tumors, FOXC1 was expressed in 5/5 BLBC tumors and 1/30 non-BLBC tumors. In cell culture models of BRCA1-mutant breast cancer, FOXC1 is associated with increased proliferation and may serve as a marker for sensitivity to PARP-inhibitor therapy with olaparib.
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Biomarcadores Tumorais , Neoplasias da Mama/genética , Fatores de Transcrição Forkhead/genética , Neoplasia de Células Basais/genética , Adulto , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos , Feminino , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Genes BRCA1 , Genes BRCA2 , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Mutação , Gradação de Tumores , Estadiamento de Neoplasias , Neoplasia de Células Basais/metabolismo , Neoplasia de Células Basais/patologia , Ftalazinas/farmacologia , Piperazinas/farmacologiaRESUMO
The Forkhead box C1 (FOXC1) transcriptional factor is a critical biomarker for basal-like breast cancer (BLBC). We recently reported that FOXC1 promotes cancer stem cell properties in BLBC by activating Smoothened (SMO)-independent Hedgehog (Hh) signaling, suggesting a FOXC1-mediated mechanism for BLBC cell function and anti-Hh therapy resistance.
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The mesoderm- and epithelial-mesenchymal transition-associated transcription factor FOXC1 is specifically overexpressed in basal-like breast cancer (BLBC), but its biochemical function is not understood. Here, we demonstrate that FOXC1 controls cancer stem cell (CSC) properties enriched in BLBC cells via activation of Smoothened (SMO)-independent Hedgehog (Hh) signaling. This non-canonical activation of Hh is specifically mediated by Gli2. Furthermore, we show that the N-terminal domain of FOXC1 (aa 1-68) binds directly to an internal region (aa 898-1168) of Gli2, enhancing the DNA-binding and transcription-activating capacity of Gli2. FOXC1 expression correlates with that of Gli2 and its targets in human breast cancers. Moreover, FOXC1 overexpression reduces sensitivity to anti-Hedgehog (Hh) inhibitors in BLBC cells and xenograft tumors. Together, these findings reveal FOXC1-mediated non-canonical Hh signaling that determines the BLBC stem-like phenotype and anti-Hh sensitivity, supporting inhibition of FOXC1 pathways as potential approaches for improving BLBC treatment.
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Neoplasias da Mama/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , Fatores de Transcrição Kruppel-Like/metabolismo , Proteínas Nucleares/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Sítios de Ligação , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Fatores de Transcrição Forkhead/química , Células HEK293 , Humanos , Fatores de Transcrição Kruppel-Like/química , Proteínas Nucleares/química , Ligação Proteica , Transdução de Sinais , Receptor Smoothened , Proteína Gli2 com Dedos de ZincoRESUMO
BACKGROUND: We investigated the effect of basal protein expression on trastuzamab response in patients with HER2-positive (HER2(+)) breast cancer who received trastuzamab (T) and in HER2(+) breast cancer cell lines. PATIENTS AND METHODS: Expression of cytokeratin (CK) 5/6, CK14, and epidermal growth factor receptor (EGFR) was evaluated after immunohistochemical staining in paraffin-embedded tissue of 97 patients with stage I to III HER2(+) breast cancer treated with chemotherapy/T. Groups with and without basal protein expression were compared with respect to clinicopathologic parameters and survival. We treated 4 cell lines (2 basal-HER2 [HCC1569, HCC1954] and 2 nonbasal HER2 [BT474, SKBR3]) each with vehicle, T 20 µg/mL, paclitaxel 0.01 µM (P), and T with P (T + P). Cell viability was assessed and HER2 pathway suppression was compared between groups using immunoblot analysis. Mammosphere formation was used to assess breast cancer stem cell properties. RESULTS: EGFR expression was significantly associated with cancer-specific survival (CSS) (P = .05). CK5/6 expression strongly correlated with overall and disease-free survival, and CSS (P = .03, P = .04, and P = .03, respectively). Statistical significance was maintained for EGFR and CK5/6 after adjustment for covariates. CK14 was not associated with survival. All cell lines expressed similar levels of HER2. T and P alone inhibited proliferation of nonbasal cell lines; T + P had an additive cytotoxic effect. Basal cells were resistant to T, P inhibited proliferation, but T + P had no additive cytotoxic effect on cell growth in basal cells. Immunoblot analysis showed a significant decrease in phosphorylated Akt levels after treatment with T or T + P in nonbasal cells but not in basal cells. Akt blockade suppressed growth of basal and nonbasal HER2(+) cells. Furthermore, basal HER2 cell lines had increased mammosphere formation, which suggests increased stem cell properties compared with nonbasal HER2 cell lines. CONCLUSION: CK5/6 and EGFR expression are predictive of worse prognosis in HER2(+) breast cancer patients treated with T. Basal HER2 breast cancer cell lines are resistant to trastuzamab, which is mediated through the Akt pathway; AKT inhibition abrogates this resistance. Basal HER2 cell lines also have increased stem cell properties, which might play a role in the resistance pathway.
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Biomarcadores Tumorais/análise , Neoplasias da Mama/patologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Receptores ErbB/biossíntese , Queratinas/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/uso terapêutico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Intervalo Livre de Doença , Receptores ErbB/análise , Feminino , Humanos , Immunoblotting , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Queratinas/análise , Pessoa de Meia-Idade , Invasividade Neoplásica , Fenótipo , Modelos de Riscos Proporcionais , Receptor ErbB-2/antagonistas & inibidores , Trastuzumab/uso terapêutico , Resultado do TratamentoRESUMO
Breast cancer is the most common cancer in women and a leading cause of cancer-related deaths for women worldwide. Various cell models have been developed to study breast cancer tumorigenesis, metastasis, and drug sensitivity. The MCF10A human mammary epithelial cell line is a widely used in vitro model for studying normal breast cell function and transformation. However, there is limited knowledge about whether MCF10A cells reliably represent normal human mammary cells. MCF10A cells were grown in monolayer, suspension (mammosphere culture), three-dimensional (3D) "on-top" Matrigel, 3D "cell-embedded" Matrigel, or mixed Matrigel/collagen I gel. Suspension culture was performed with the MammoCult medium and low-attachment culture plates. Cells grown in 3D culture were fixed and subjected to either immunofluorescence staining or embedding and sectioning followed by immunohistochemistry and immunofluorescence staining. Cells or slides were stained for protein markers commonly used to identify mammary progenitor and epithelial cells. MCF10A cells expressed markers representing luminal, basal, and progenitor phenotypes in two-dimensional (2D) culture. When grown in suspension culture, MCF10A cells showed low mammosphere-forming ability. Cells in mammospheres and 3D culture expressed both luminal and basal markers. Surprisingly, the acinar structure formed by MCF10A cells in 3D culture was positive for both basal markers and the milk proteins ß-casein and α-lactalbumin. MCF10A cells exhibit a unique differentiated phenotype in 3D culture which may not exist or be rare in normal human breast tissue. Our results raise a question as to whether the commonly used MCF10A cell line is a suitable model for human mammary cell studies.
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Mama/citologia , Linhagem Celular/citologia , Células Epiteliais/citologia , Animais , Biomarcadores/análise , Adesão Celular , Técnicas de Cultura de Células , Linhagem Celular/química , Linhagem Celular/efeitos dos fármacos , Forma Celular , Colágeno , Colágeno Tipo I , Meios de Cultura/farmacologia , Combinação de Medicamentos , Células Epiteliais/química , Células Epiteliais/efeitos dos fármacos , Feminino , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Queratinas/análise , Laminina , Proteínas de Membrana/análise , Proteínas do Leite/análise , Fenótipo , Proteoglicanas , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Células-Tronco/química , Células-Tronco/citologia , Vimentina/análiseRESUMO
BACKGROUND: Diagnosis of basal-like breast cancer (BLBC) remains a bottleneck to conducting effective clinical trials for this aggressive subtype. We postulated that elevated expression of Forkhead Box transcription factor C1 (FOXC1) is a simple and accurate diagnostic biomarker for BLBC. METHODS: Accuracy of FOXC1 expression in identifying BLBC was compared with the PAM50 gene expression panel in gene expression microarray (GEM) (n = 1992) and quantitative real-time polymerase chain reaction (qRT-PCR) (n = 349) datasets. A FOXC1-based immunohistochemical (IHC) assay was developed and assessed in 96 archival formalin-fixed, paraffin-embedded (FFPE) breast cancer samples that also underwent PAM50 profiling. All statistical tests were two-sided. RESULTS: A FOXC1-based two-tier assay (IHC +/- qRT-PCR) accurately identified BLBC (AUC = 0.88) in an independent cohort of FFPE samples, validating the accuracy of FOXC1-defined BLBC in GEM (AUC = 0.90) and qRT-PCR (AUC = 0.88) studies, when compared with platform-specific PAM50-defined BLBC. The hazard ratio (HR) for disease-specific survival in patients having FOXC1-defined BLBC was 1.71 (95% CI = 1.31 to 2.23, P < .001), comparable to PAM50 assay-defined BLBC (HR = 1.74, 95% CI = 1.40 to 2.17, P < .001). FOXC1 expression also predicted the development of brain metastasis. Importantly, unlike triple-negative or Core Basal IHC definitions, a FOXC1-based definition is able to identify BLBC in both ER+ and HER2+ patients. CONCLUSION: A FOXC1-based two-tier assay, by virtue of being rapid, simple, accurate, and cost-effective may emerge as the diagnostic assay of choice for BLBC. Such a test could substantially improve clinical trial enrichment of BLBC patients and accelerate the identification of effective chemotherapeutic options for this aggressive disease.
Assuntos
Biomarcadores Tumorais/análise , Neoplasias Encefálicas/diagnóstico , Neoplasias da Mama/química , Neoplasias da Mama/diagnóstico , Fatores de Transcrição Forkhead/análise , Adulto , Idoso , Área Sob a Curva , Neoplasias Encefálicas/química , Neoplasias Encefálicas/secundário , Neoplasias da Mama/patologia , Carcinoma Basocelular/química , Carcinoma Basocelular/diagnóstico , Feminino , Formaldeído , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Inclusão em Parafina , Valor Preditivo dos Testes , Prognóstico , Curva ROC , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fixação de Tecidos/métodos , Regulação para CimaRESUMO
BACKGROUND: Human basal-like breast cancer (BLBC) has a poor prognosis and is often identified by expression of the epidermal growth factor receptor (EGFR). BLBC remains a major clinical challenge because its pathogenesis is not well understood, thus hindering efforts to develop targeted therapies. Recent data implicate the forkhead box C1 (FOXC1) transcription factor as an important prognostic biomarker and functional regulator of BLBC, but its regulatory mechanism and impact on BLBC tumorigenesis remain unclear. METHODS: The association between FOXC1 and EGFR expression in human breast cancer was examined by immunohistochemistry in formalin-fixed tissues and analysis of the TCGA database. The regulation of FOXC1 by EGFR activation was investigated in MDA-MB-468 cells using immunoblotting, qRT-PCR, and luciferase activity assays. This EGFR effect on FOXC1 expression was confirmed using the MDA-MB-468 xenograft model. RESULTS: Both FOXC1 mRNA and protein levels significantly correlated with EGFR expression in human breast tumors. EGFR activation induced FOXC1 transcription through the ERK and Akt pathways in BLBC. EGFR inhibition in vivo reduced FOXC1 expression in xenograft tumors. We also found that FOXC1 knockdown impaired the effects of EGF on BLBC cell proliferation, migration, and invasion. CONCLUSIONS: Our findings uncover a novel EGFR-FOXC1 signaling axis critical for BLBC cell functions, supporting the notion that intervention in the FOXC1 pathway may provide potential modalities for BLBC treatment.
Assuntos
Receptores ErbB/genética , Fatores de Transcrição Forkhead/genética , RNA Mensageiro/análise , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Receptores ErbB/análise , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Fatores de Transcrição Forkhead/análise , Fatores de Transcrição Forkhead/metabolismo , Gefitinibe , Regulação Neoplásica da Expressão Gênica , Sistema de Sinalização das MAP Quinases , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quinazolinas/uso terapêutico , RNA Interferente Pequeno/genética , Transfecção , Neoplasias de Mama Triplo Negativas/química , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Regulação para CimaRESUMO
OBJECTIVE: To determine Claudin-3 expression and its regulatory factors during embryo implantation. DESIGN: Experimental mouse models and cell culture. SETTING: University research laboratory. ANIMAL(S): Sexually mature female CD-1 strain mice. INTERVENTION(S): Ovariectomy and treatments. MAIN OUTCOME MEASURE(S): In situ hybridization and immunohistochemistry for detecting Claudin-3 messenger RNA and protein expression in mouse uterus, respectively; Western blot for detecting protein levels; immunofluorescence for detecting Claudin-3 protein in cultured cells. RESULT(S): Claudin-3 is strongly expressed in the uterine luminal epithelium on days 3 and 4 of pregnancy, and diminished at day 5 implantation sites. Then it is expressed at secondary decidual zone on day 8. Pseudopregnant uteri have a similar expression pattern as pregnant uteri from days 1-5. Claudin-3 expression is down-regulated after delayed implantation is activated by estrogen (E) treatment. Meanwhile Claudin-3 expression is stimulated by artificial decidualization. In ovariectomized mice, P induces Claudin-3 expression in the luminal epithelium, which is abrogated by P receptor antagonist RU486. Heparin-binding-epidermal growth factor (HB-EGF) down-regulates Claudin-3 expression, but enhances transcription factor Snail expression. In human endometrial epithelial ECC-1 cells, both E and P could stimulate Claudin-3 expression, whereas HB-EGF decreases Claudin-3 and increases Snail expression. CONCLUSION(S): Claudin-3 expression in uterine luminal epithelium is stimulated by P and suppressed by HB-EGF in mice and humans.