RESUMO
Initiation of zygotic transcription in mammals is poorly understood. In mice, zygotic transcription is first detected shortly after pronucleus formation in 1-cell embryos, but the identity of the transcribed loci and mechanisms regulating their expression are not known. Using total RNA-Seq, we have found that transcription in 1-cell embryos is highly promiscuous, such that intergenic regions are extensively expressed and thousands of genes are transcribed at comparably low levels. Striking is that transcription can occur in the absence of defined core-promoter elements. Furthermore, accumulation of translatable zygotic mRNAs is minimal in 1-cell embryos because of inefficient splicing and 3' processing of nascent transcripts. These findings provide novel insights into regulation of gene expression in 1-cell mouse embryos that may confer a protective mechanism against precocious gene expression that is the product of a relaxed chromatin structure present in 1-cell embryos. The results also suggest that the first zygotic transcription itself is an active component of chromatin remodeling in 1-cell embryos.
Assuntos
Regiões 3' não Traduzidas/fisiologia , Embrião de Mamíferos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Splicing de RNA/fisiologia , Transcrição Gênica/fisiologia , Zigoto/metabolismo , Animais , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/fisiologia , Embrião de Mamíferos/citologia , Camundongos , Zigoto/citologiaRESUMO
Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer and significantly associated with poor prognosis and high risk of recurrence. miR-34a has been identified as a potent tumor suppressor whose expression is dramatically downregulated in TNBC. Currently, rectification of miRNA abnormality serves as a novel tumor therapeutic strategy. miR-34a is thus used as powerful antitumor agent for miRNA-based therapy against TNBC. However, miRNA-based antitumor therapy is challenged by effective targeted delivery of miRNA. In the present study, nanodiamond (ND), protamine (PS) and folic acid (FA) were used to construct ND-based layer-by-layer nanohybrids through a self-assembly approach for targeted miR-34a delivery in TNBC cells and xenograft TNBC tumors. We found that the targeted delivery of miR-34a remarkably suppressed cell proliferation, migration and induced the apoptosis of TNBC cells in vitro and inhibited tumor growth in vivo via down-regulating Fra-1 expression. The data suggest a great potential of ND-based nanohybrids for targeted intratumoral delivery of miR-34a for TNBC therapy.
RESUMO
Metastatic relapse is a leading cause of cancer-associated death and one of the major obstacles for effective therapy against triple-negative breast cancer. To address this problem, a miRNA-delivering nanocapsule technology based on hyaluronic acid (HA)/protamine sulfate (PS) interpolyelectrolyte complexes (HP-IPECs) is developed for efficient encapsulation and intracellular delivery microRNA-34a (miR-34a), which is a potent endogenous tumor suppressor of breast cancer. The nanocapsules are successfully generated through a self-assembly approach mediated by an electrostatic interaction. In vitro and in vivo experiments illustrate that miR-34a can be efficiently encapsulated into HP-IPECs and delivered into breast cancer cells or breast cancer tissues. Nanocomplex-assisted delivery of miR-34a induces cell apoptosis and suppresses migration, proliferation, and tumor growth of breast cancer cells via targeting CD44 and a Notch-1-signaling pathway. The obtained results suggest that HP-IPECs have a great potential as a biodegradable vector for microRNA-based therapy against triple-negative breast cancer.
Assuntos
Ácido Hialurônico/química , MicroRNAs/metabolismo , Nanocápsulas/química , Protaminas/química , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Apoptose , Morte Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Eletrólitos , Feminino , Técnicas de Transferência de Genes , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias de Mama Triplo Negativas/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Metastatic relapse, development of drug resistance in cancer cells and adverse side effects of chemotherapeutic agents are the major obstacles for effective chemotherapy against triple-negative breast cancer. To address these problems, miR-34a, a potent endogenous tumor suppressive molecule in breast cancer, was co-encapsulated with doxorubicin (DOX) into hyaluronic acid (HA)-chitosan (CS) nanoparticles (NPs) and simultaneously delivered into breast cancer cells for improved therapeutic effects of drug. DOX-miR-34a co-loaded HA-CS NPs were successfully prepared through ionotropic gelation method in water. In vitro and in vivo experiments showed that miR-34a and DOX can be efficiently encapsulated into HA-CS NPs and delivered into tumor cells or tumor tissues and enhance anti-tumor effects of DOX by suppressing the expression of non-pump resistance and anti-apoptosis proto-oncogene Bcl-2. In addition, intracellular restoration of miR-34a inhibited breast cancer cell migration via targeting Notch-1 signaling. The obtained data suggest that co-delivery of DOX and miR-34a could achieve synergistic effects on tumor suppression and nanosystem-based co-delivery of tumor suppressive miRNAs and chemotherapeutic agents may be a promising combined therapeutic strategy for enhanced anti-tumor therapy.
Assuntos
Quitosana/química , Doxorrubicina/uso terapêutico , Sistemas de Liberação de Medicamentos , Ácido Hialurônico/química , MicroRNAs/metabolismo , Nanopartículas/química , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Sequência de Bases , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Doxorrubicina/farmacologia , Endocitose/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Luz , Camundongos , MicroRNAs/genética , Dados de Sequência Molecular , Nanopartículas/ultraestrutura , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Estabilidade de RNA/efeitos dos fármacos , Espalhamento de Radiação , Solventes , Resultado do Tratamento , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
The expression of miR-203 has been reported to be significantly down-regulated in esophageal cancer. We showed here that overexpression of miR-203 in esophageal cancer cells dramatically increased cell apoptosis and inhibited cell proliferation, migration and invasion as well as tumor growth and down-regulated miR-21 expression. We subsequently identified that small GTPase Ran was a target gene of miR-203. Furthermore, Ran restoration partially counteracted the tumor suppressive effects of miR-203 and increased miR-21 expression. Taken together, our findings suggest that miR-203 may act as novel tumor suppressor in esophageal cancer through down-regulating the expression of Ran and miR-21.
Assuntos
Carcinoma de Células Escamosas/metabolismo , Neoplasias Esofágicas/metabolismo , MicroRNAs/genética , Proteína ran de Ligação ao GTP/genética , Regiões 3' não Traduzidas , Animais , Apoptose , Sequência de Bases , Sítios de Ligação , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Regulação para Baixo , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/metabolismo , Invasividade Neoplásica , Transplante de Neoplasias , Interferência de RNA , Carga Tumoral , Proteína ran de Ligação ao GTP/metabolismoRESUMO
We report an innovative approach for miRNA-203 delivery in esophageal cancer cells using protamine sulphate (PS)-nanodiamond (ND) nanoparticles. The efficient delivery of miR-203 significantly suppressed the proliferation and migration of cancer cells through targeting Ran and ΔNp63, exhibiting a great potential for PS@ND nanoparticles in miRNA-based cancer therapy.