RESUMEN
Preclinical models that display spontaneous metastasis are necessary to improve the therapeutic options for hormone receptor-positive breast cancers. Within this study, detailed cellular and molecular characterization was conducted on MCa-P1362, a newly established mouse model of metastatic breast cancer that is syngeneic in BALB/c mice. MCa-P1362 cancer cells express estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2. MCa-P1362 cancer cells proliferate in vitro and in vivo in response to estrogen, yet do not depend on steroid hormones for growth and tumor progression. Analysis of MCa-P1362 tumor explants revealed the tumors contained a mixture of cancer cells and mesenchymal stromal cells. Through transcriptomic and functional analyses of both cancer and stromal cells, stem cells were detected within both populations. Functional studies demonstrated that MCa-P1362 cancer stem cells drove tumor initiation, whereas stromal cells from these tumors contributed to drug resistance. MCa-P1362 may serve as a useful preclinical model to investigate the cellular and molecular basis of breast tumor progression and therapeutic resistance.
Asunto(s)
Adenocarcinoma , Células Madre Mesenquimatosas , Ratones Endogámicos BALB C , Receptor ErbB-2 , Receptores de Estrógenos , Animales , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/patología , Femenino , Humanos , Receptor ErbB-2/metabolismo , Ratones , Receptores de Estrógenos/metabolismo , Adenocarcinoma/patología , Adenocarcinoma/metabolismo , Receptores de Progesterona/metabolismo , Neoplasias de la Mama/patología , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/genética , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Línea Celular Tumoral , Neoplasias Mamarias Experimentales/patología , Neoplasias Mamarias Experimentales/metabolismoRESUMEN
Breast cancer (BC) accounts for significant morbidity and mortality among women worldwide. About one in three patients with breast cancer present with lymph node (LN) metastasis and LN status is one of the most important prognostic predictors in patients with BC. In addition to their prognostic value, LNs initiate adaptive immunity against BC. Yet, BC cells often avoid immune-mediated destruction in LNs. This review provides an overview of the ways by which BC cells modulate LN stromal and hematopoietic cells to promote metastasis and immune evasion.
Asunto(s)
Neoplasias de la Mama/inmunología , Neoplasias de la Mama/patología , Metástasis Linfática/inmunología , Metástasis Linfática/patología , Escape del Tumor/inmunología , Femenino , HumanosRESUMEN
Tumor cells promote immune evasion through upregulation of programmed death-ligand 1 (PD-L1) that binds with programmed cell death protein 1 (PD1) on cytotoxic T cells and promote dysfunction. Though therapeutic efficacy of anti-PD1 antibody has remarkable effects on different type of cancers it is less effective in breast cancer (BC). Hence, more details understanding of PD-L1-mediated immune evasion is necessary. Here, we report BC cells secrete extracellular vesicles in form of exosomes carry PD-L1 and are highly immunosuppressive. Transforming growth factor beta (TGF-ß) present in tumor microenvironment orchestrates BC cell secreted exosomal PD-L1 load. Circulating exosomal PD-L1 content is highly correlated with tumor TGF-ß level. The later also found to be significantly associated with CD8+CD39+, CD8+PD1+ T-cell phenotype. Recombinant TGF-ß1 dose dependently induces PD-L1 expression in Texos in vitro and blocking of TGF-ß dimmed exosomal PD-L1 level. PD-L1 knocked down exosomes failed to suppress effector activity of activated CD8 T cells like tumor exosomes. While understanding its effect on T-cell receptor signaling, we found siPD-L1 exosomes failed to block phosphorylation of src family proteins, linker for activation of T cells and phosphoinositide phospholipase Cγ of CD8 T cells more than PD-L1 exosomes. In vivo inhibition of exosome release and TGF-ß synergistically attenuates tumor burden by promoting Granzyme and interferon gamma release in tumor tissue depicting rejuvenation of exhausted T cells. Thus, we establish TGF-ß as a promoter of exosomal PD-L1 and unveil a mechanism that tumor cells follow to promote CD8 T-cell dysfunction.
Asunto(s)
Antígeno B7-H1/metabolismo , Neoplasias de la Mama/inmunología , Linfocitos T CD8-positivos/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Compuestos de Anilina/administración & dosificación , Animales , Antígeno B7-H1/sangre , Antígeno B7-H1/genética , Benzamidas/administración & dosificación , Compuestos de Bencilideno/administración & dosificación , Mama/patología , Neoplasias de la Mama/sangre , Neoplasias de la Mama/patología , Linfocitos T CD8-positivos/metabolismo , Carcinoma de Ehrlich/inmunología , Carcinoma de Ehrlich/patología , Línea Celular Tumoral , Dioxoles/administración & dosificación , Exosomas/efectos de los fármacos , Exosomas/metabolismo , Femenino , Técnicas de Inactivación de Genes , Granzimas/metabolismo , Voluntarios Sanos , Humanos , Interferón gamma/metabolismo , Ratones , Persona de Mediana Edad , Fosforilación/efectos de los fármacos , Fosforilación/inmunología , Cultivo Primario de Células , Receptor Tipo I de Factor de Crecimiento Transformador beta/antagonistas & inhibidores , Receptor Tipo I de Factor de Crecimiento Transformador beta/metabolismo , Proteínas Recombinantes/metabolismo , Transducción de Señal/inmunología , Escape del Tumor/efectos de los fármacos , Escape del Tumor/inmunología , Microambiente Tumoral/inmunologíaRESUMEN
BACKGROUND: Cancer-associated fibroblasts (CAFs) are known to impact on tumour behaviour, but the mechanisms controlling this are poorly understood. METHODS: Breast normal fibroblasts (NFs) or CAFs were isolated from cancers by laser microdissection or were cultured. Fibroblasts were transfected to manipulate miR-222 or Lamin B receptor (LBR). The fibroblast-conditioned medium was collected and used to treat epithelial BC lines MDA-MB-231 and MDA-MB-157. Migration, invasion, proliferation or senescence was assessed using transwell, MTT or X-gal assays, respectively. RESULTS: MiR-222 was upregulated in CAFs as compared with NFs. Ectopic miR-222 expression in NFs induced CAF-like expression profiles, while miR-222 knockdown in CAFs inhibited CAF phenotypes. LBR was identified as a direct miR-222 target, and was functionally relevant since LBR knockdown phenocopied miR-222 overexpression and LBR overexpression phenocopied miR-222 knockdown. MiR-222 overexpression, or LBR knockdown, was sufficient to induce NFs to show the CAF characteristics of enhanced migration, invasion and senescence, and furthermore, the conditioned medium from these fibroblasts induced increased BC cell migration and invasion. The reverse manipulations in CAFs inhibited these behaviours in fibroblasts, and inhibited paracrine influences on BC cells. CONCLUSION: MiR-222/LBR have key roles in controlling pro-progression influences of CAFs in BC. This pathway may present therapeutic opportunities to inhibit CAF-induced cancer progression.
Asunto(s)
Neoplasias de la Mama/genética , Fibroblastos Asociados al Cáncer/metabolismo , Carcinoma/genética , MicroARNs/genética , Receptores Citoplasmáticos y Nucleares/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Carcinoma/metabolismo , Carcinoma/patología , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Técnicas de Reprogramación Celular , Senescencia Celular , Medios de Cultivo Condicionados , Femenino , Fibroblastos/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Captura por Microdisección con Láser , Invasividad Neoplásica , Metástasis de la Neoplasia , Receptor de Lamina BRESUMEN
Breast cancer is the most deadly cancer among women and the second leading cause of cancer death worldwide. Treatment effectiveness is complicated with tumor invasiveness/drug resistance. To tailor treatments more effectively to individual patients, it is important to define tumor growth and metastasis at molecular levels. SDCBP is highly overexpressed and associated with a strikingly poor prognosis in breast cancer. However the post transcriptional regulation of SDCBP overexpression remains to be an unexplored area. Our study reveals that miR-216b directly regulates SDCBP expression by binding to its 3'UTR region. miR-216b is a tumor suppressive miRNA and it is underexpressed during metastatic breast cancer. Consequently, overexpression of miR-216b resulted in decreased proliferation, migration and invasion in BC cell lines by modulating the expression of SDCBP. Inhibition of miR-216b divergent the tumor suppressive role by inducing the growth proliferation, migration and invasion in vitro. There is therefore a negative correlation between the expression of miR-216b and its target gene SDCBP in the BC tissue samples as well as cell lines. Simultaneous expression of miR-216b and SDCBP rescued the growth, migration and invasion effect suggesting that tumor suppressive action of miR-216b may be directly mediated by SDCBP. In summary, the study identifies miR-216b as a regulator of SDCBP expression in breast cancer which can potentially be targeted for developing newer therapies for the effective treatment of this killer disease.
Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/secundario , Proliferación Celular/genética , Genes Supresores de Tumor , MicroARNs/metabolismo , Sinteninas/genética , Neoplasias de la Mama/patología , Femenino , Humanos , Células Tumorales CultivadasRESUMEN
Organometallic metal(arene) anticancer agents require ligand exchange for their anticancer activity and this is generally believed to confer low selectivity for potential cellular targets. However, using an integrated proteomics-based target-response profiling approach as a potent hypothesis-generating procedure, we found an unexpected target selectivity of a ruthenium(arene) pyridinecarbothioamide (plecstatin) for plectin, a scaffold protein and cytolinker, which was validated in a plectin knock-out model inâ vitro. Plectin targeting shows potential as a strategy to inhibit tumor invasiveness as shown in cultured tumor spheroids while oral administration of plecstatin-1 to mice reduces tumor growth more efficiently in the invasive B16â melanoma than in the CT26â colon tumor model.
Asunto(s)
Antineoplásicos/farmacología , Compuestos Organometálicos/farmacología , Plectina/efectos de los fármacos , Compuestos de Rutenio/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Técnicas de Inactivación de Genes , Ontología de Genes , Humanos , Ratones , Neoplasias Experimentales/patología , Compuestos Organometálicos/química , Plectina/genética , Compuestos de Rutenio/químicaRESUMEN
We investigated the expression of -CXC chemokine ligand 13 (CXCL13) and its receptor -CXC chemokine receptor 5 (CXCR5) in 98 breast cancer (BC) patients with infiltrating duct carcinoma, out of which 56 were found lymph node metastasis (LNM) positive. Interestingly, co-expression of CXCL13 and CXCR5 showed a significant correlation with LNM. Since, epithelial to mesenchymal transition (EMT) is highly associated with metastasis we investigated EMT-inducing potential of CXCL13 in BC cell lines. In CXCL13-stimulated BC cells, expression of various mesenchymal markers (Vimentin, N-cadherin), EMT regulators (Snail, Slug), and matrix metalloproteinase-9 (MMP9) was increased, whereas the expression of epithelial marker E-cadherin was found to be decreased. In addition, expression of receptor activator of nuclear factor kappa-B ligand (RANKL), which is known to regulate MMP9 expression via Src activation, was also significantly increased after CXCL13 stimulation. Using specific protein kinase inhibitors, we confirmed that CXCL13 stimulated EMT and MMP9 expression via RANKL-Src axis in BC cell lines. To further validate this observation, we examined gene expression patterns in primary breast tumors and detected significantly higher expression of various mesenchymal markers and regulators in CXCL13-CXCR5 co-expressing patients. Therefore, this study showed the EMT-inducing potential of CXCL13 as well as demonstrated the prognostic value of CXCL13-CXCR5 co-expression in primary BC. Moreover, CXCL13-CXCR5-RANKL-Src axis may present a therapeutic target in LNM positive BC patients.
Asunto(s)
Neoplasias de la Mama/patología , Quimiocina CXCL13/metabolismo , Transición Epitelial-Mesenquimal , Metástasis Linfática/patología , Receptores CXCR5/metabolismo , Adulto , Anciano , Antígenos CD/biosíntesis , Biomarcadores de Tumor/metabolismo , Cadherinas/biosíntesis , Línea Celular Tumoral , Movimiento Celular , Quimiocina CXCL13/antagonistas & inhibidores , Quimiocina CXCL13/biosíntesis , Femenino , Furanos/farmacología , Humanos , Indoles/farmacología , Metaloproteinasa 9 de la Matriz/biosíntesis , Persona de Mediana Edad , Inhibidores de las Quinasa Fosfoinosítidos-3 , Piridinas/farmacología , Pirimidinas/farmacología , Ligando RANK/biosíntesis , Ligando RANK/genética , ARN Mensajero/biosíntesis , Receptores CXCR5/antagonistas & inhibidores , Receptores CXCR5/biosíntesis , Transducción de Señal , Factores de Transcripción de la Familia Snail , Sulfonamidas/farmacología , Factores de Transcripción/biosíntesis , Vimentina/biosíntesis , Familia-src Quinasas/antagonistas & inhibidoresRESUMEN
Preclinical models that display spontaneous metastasis are necessary to improve therapeutic options for hormone receptor positive breast cancers. In this study, we conducted a detailed cellular and molecular characterization of MCa-P1362, a novel syngeneic Balb/c mouse model of metastatic breast cancer. MCa-P1362 cancer cells expressed estrogen receptors (ER), progesterone receptors (PR), and HER-2 receptors. MCa-P1362 cells proliferate in vitro and in vivo in response to estrogen, yet do not depend on steroid hormones for tumor progression. Further characterization of MCa-P1362 tumor explants shows that they contain a mixture of epithelial cancer cells and stromal cells. Based on transcriptomic and functional analyses of cancer and stromal cells, stem cells are present in both populations. Functional studies demonstrate that crosstalk between cancer and stromal cells promotes tumor growth, metastasis, and drug resistance. MCa-P1362 may serve as a useful preclinical model to investigate the cellular and molecular basis of hormone receptor positive tumor progression and therapeutic resistance.
RESUMEN
SRY-related high-mobility group box 9 (SOX9) is an indispensable transcription factor that regulates multiple developmental pathways related to stemness, differentiation, and progenitor development. Previous studies have demonstrated that the SOX9 protein directs pathways involved in tumor initiation, proliferation, migration, chemoresistance, and stem cell maintenance, thereby regulating tumorigenesis as an oncogene. SOX9 overexpression is a frequent event in breast cancer (BC) subtypes. Of note, the molecular mechanisms and functional regulation underlying SOX9 upregulation during BC progression are still being uncovered. The focus of this review is to appraise recent advances regarding the involvement of SOX9 in BC pathogenesis. First, we provide a general overview of SOX9 structure and function, as well as its involvement in various kinds of cancer. Next, we discuss pathways of SOX9 regulation, particularly its miRNA-mediated regulation, in BC. Finally, we describe the involvement of SOX9 in BC pathogenesis via its regulation of pathways involved in regulating cancer hallmarks, as well as its clinical and therapeutic importance. In general, this review article aims to serve as an ample source of knowledge on the involvement of SOX9 in BC progression. Targeting SOX9 activity may improve therapeutic strategies to treat BC, but precisely inhibiting SOX9 using drugs and/or small peptides remains a huge challenge for forthcoming cancer research.
Asunto(s)
Apoptosis , Neoplasias de la Mama/metabolismo , Proliferación Celular , Células Madre Neoplásicas , Neovascularización Patológica/metabolismo , Factor de Transcripción SOX9/metabolismo , Apoptosis/genética , Neoplasias de la Mama/irrigación sanguínea , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Proliferación Celular/genética , Progresión de la Enfermedad , Resistencia a Antineoplásicos/genética , Epigénesis Genética , Femenino , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Neovascularización Patológica/genética , Procesamiento Postranscripcional del ARN , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Factor de Transcripción SOX9/química , Factor de Transcripción SOX9/genéticaRESUMEN
Reports on the association of TGF-ß1 polymorphisms with breast cancer (BC) have been conflicting, inconsistent, inconclusive, and controversial. PubMed, EMBASE, and Google Scholar were used to identify studies on TGF-ß1 polymorphisms and BC risk. Data were extracted independently, and of the initial 3043 studies, 39 case-control studies were eligible for inclusion in the meta-analysis. Information from these studies was extracted, and the overall associations of three TGF-ß1 polymorphisms (TGF-ß1 29>T/C, TGF-ß1-509 C/T, and TGF-ß1*6A) with BC risk were analyzed using overall allele, homozygous, heterozygous, recessive, and dominant models. None of the three TGF-ß1 polymorphisms studied had a significant influence on the development of BC. However, stratified analysis revealed a positive correlation between the TGF-ß1 29T>C polymorphism and BC risk according to a heterozygous model of the Asian population (odds ratio (OR) = 1.115, 95% confidence interval (CI) = 1.006-1.237, p = 0.039). Interestingly, this polymorphism was associated with lower odds of BC according to a heterozygous model of the Middle Eastern population (OR = 0.602, 95% CI = 0.375-0.966, p = 0.035). Thus, our analysis of large datasets indicates that the TGF-ß1 29T>C polymorphism is significantly associated with BC risk in the Asian population. In contrast, the TGF-ß1*6A and TGF-ß1-509 C/T polymorphisms failed to show an association with BC.
RESUMEN
MicroRNAs (miRNAs/or miR) are a type of small, non-coding RNAs that regulate gene expression by binding to 3'-UTRs of the target genes. miRNAs can serve as oncogenes or tumor suppressors, and have prognostic and therapeutic values that may be directly applicable in the clinic. miR-216b is located on chromosome 2p16.1. Accumulating evidence suggests that it acts as a tumor suppressor and its downregulation may play a significant role in cancer biology through the dysregulation of various oncogenes and signaling pathways related to cancer cell proliferation, cell cycle progression, migration, invasion, apoptosis, and chemoresistance. In this review, we discuss the aberrant expression of miR-216b in cancer and its role in tumor pathogenesis, which will offer novel insights into its clinical applications.
Asunto(s)
Biomarcadores de Tumor/genética , Regulación Neoplásica de la Expresión Génica , Genes Supresores de Tumor , MicroARNs/genética , Neoplasias/genética , Apoptosis/genética , Proliferación Celular/genética , Humanos , Neoplasias/clasificación , Neoplasias/terapia , Pronóstico , Transducción de Señal/genéticaRESUMEN
The Notch signaling pathway, which is highly conserved from sea urchins to humans, plays an important role in cell-differentiation, survival, proliferation, stem-cell renewal, and determining cell fate during development and morphogenesis. It is well established that signaling pathways are dysregulated in a wide-range of diseases, including human malignancies. Studies suggest that the dysregulation of the Notch pathway contributes to carcinogenesis, cancer stem cell renewal, angiogenesis, and chemo-resistance. Elevated levels of Notch receptors and ligands have been associated with cancer-progression and poor survival. Furthermore, the Notch signaling pathway regulates the transcriptional activity of key target genes through crosstalk with several other signaling pathways. Indeed, increasing evidence suggests that the Notch signaling pathway may serve as a therapeutic target for the treatment of several cancers, including breast cancer. Researchers have demonstrated the anti-tumor properties of Notch inhibitors in various cancer types. Currently, Notch inhibitors are being evaluated for anticancer efficacy in a number of clinical-trials. However, because there are multiple Notch receptors that can exhibit either oncogenic or tumor-suppressing roles in various cells, it is important that the Notch inhibitors are specific to particular receptors that are tumorigenic in nature. This review critically evaluates existing Notch inhibitory drugs and strategies and summarizes the previous discoveries, current understandings, and recent developments in support of Notch receptors as therapeutic targets in breast cancer.
Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Terapia Molecular Dirigida , Neovascularización Patológica/tratamiento farmacológico , Oncogenes , Receptores Notch/antagonistas & inhibidores , Animales , Neoplasias de la Mama/metabolismo , Femenino , Humanos , Neovascularización Patológica/metabolismo , Receptores Notch/metabolismo , Transducción de SeñalRESUMEN
MicroRNAs and RNA-binding proteins exert regulation on >60% of coding genes, yet interplay between them is little studied. Canonical microRNA binding occurs by base-pairing of microRNA 3'-ends to complementary "seed regions" in mRNA 3'UTRs, resulting in translational repression. Similarly, regulatory RNA-binding proteins bind to mRNAs, modifying stability or translation. We investigated post-transcriptional regulation acting on the xenobiotic pump ABCB1/P-glycoprotein, which is implicated in cancer therapy resistance. We characterised the ABCB1 UTRs in primary breast cancer cells and identified UTR sequences that responded to miR-19b despite lacking a canonical binding site. Sequences did, however, contain consensus sites for the RNA-binding protein HuR. We demonstrated that a tripartite complex of HuR, miR-19b and UTR directs repression of ABCB1/P-glycoprotein expression, with HuR essential for non-canonical miR-19b binding thereby controlling chemosensitivity of breast cancer cells. This exemplifies a new cooperative model between RNA-binding proteins and microRNAs to expand the repertoire of mRNAs that can be regulated. This study suggests a novel therapeutic target to impair P-glycoprotein mediated drug efflux, and also indicates that current microRNA binding predictions that rely on seed regions alone may be too conservative.
Asunto(s)
Neoplasias de la Mama/metabolismo , Proteína 1 Similar a ELAV/metabolismo , MicroARNs/metabolismo , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Antibióticos Antineoplásicos/farmacología , Mama/metabolismo , Línea Celular , Doxorrubicina/farmacología , Resistencia a Antineoplásicos , Femenino , Humanos , ARN Mensajero/metabolismoRESUMEN
In late stages of cancer, TGF-ß promotes the metastasis process by enhancing the invasiveness of cancer cells and inducing the epithelial-to-mesenchymal transition (EMT), a process that is concomitantly associated with breast cancer metastasis. Metastasis comprises of multiple steps with the regulation of complex network of signaling. Metastasis is associated with both the EMT and cell proliferation, but yet it has not been clearly distinguished how the balance between the cell proliferation and EMT is maintained together. Recently, it has been accounted that a transcription factor, NFAT has an important role for switching tumor suppressive to progressive effect of TGF-ß and NFAT has a role in TGF-ß mediated EMT by regulating N-cadherin. CDC 25A phosphatase, an important cell cycle regulator is overexpressed in breast cancer. Our results demonstrate that TGF-ß regulating the CDC 25A in a Smad2 dependent way, translocates NFAT to nucleus and NFAT in co-operation with Smad2 promotes the tumor progression by upregulating the CDK2, CDK4, and cyclin E. This result signifies that TGF-ß by regulating NFAT in different ways maintains the balance between EMT and cell proliferation mechanism concurrently during the late stage of breast cancer.
Asunto(s)
Factores de Transcripción NFATC/metabolismo , Proteína Smad2/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Fosfatasas cdc25/metabolismo , Apoptosis , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Cadherinas/metabolismo , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ciclina D1/genética , Ciclina D1/metabolismo , Ciclina E/genética , Ciclina E/metabolismo , Quinasa 2 Dependiente de la Ciclina/genética , Quinasa 2 Dependiente de la Ciclina/metabolismo , Quinasa 4 Dependiente de la Ciclina/genética , Quinasa 4 Dependiente de la Ciclina/metabolismo , Transición Epitelial-Mesenquimal/efectos de los fármacos , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Factores de Transcripción NFATC/antagonistas & inhibidores , Factores de Transcripción NFATC/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal/efectos de los fármacos , Proteína Smad2/antagonistas & inhibidores , Proteína Smad2/genética , Proteína Smad2/farmacología , Factor de Crecimiento Transformador beta/farmacología , Fosfatasas cdc25/antagonistas & inhibidores , Fosfatasas cdc25/genéticaRESUMEN
Epithelial to mesenchymal transition (EMT) is a secondary phenomenon concomitantly associated with the tumor progression. The regulatory signals and mechanistic details of EMT are not fully elucidated. Here, we shared a TGF-ß mediated mechanism of EMT in breast cancer (MDA-MB 231) cells. Initial exposure of TGF-ß for 48 h, enhanced the rate of cell proliferation and associated with EMT of MDA-MB 231 cells. The EMT was characterized by observing the increased N-cadherin, fibronectin, Snail expression and associated with the morphological change with a reduced E-cadherin expression. NFAT, a transcription factor, alters tumor suppressive function of TGF-ß towards tumor progression. Up regulation of NFAT, coupled with a foremost translocation of one oncogenic protein SnoN from cytoplasm to nucleus was noticed during this TGF-ß mediated EMT. Silencing of NFAT also showed the inhibition of TGF-ß mediated EMT characterized by down regulation of N-cadherin and associated with reduced expression of SnoN. In addition, it was also observed that NFAT sequestering the Smad3 prevents the proteasome mediated degradation of SnoN and this SnoN has a role on the regulation of MMP-2, MMP-9 activity. Increased Smad3-SnoN interaction and proteasome mediated degradation of SnoN were detected after silencing of NFAT with a reduced MMP-2, MMP-9 activity. All of these observations provide a fresh mechanism in which by a twofold involvement of NFAT and SnoN plays a crucial role in TGF-ß mediated EMT by recruiting the effector molecules N-cadherin and MMP-2, MMP-9.