RESUMEN
The clinical management of cancer reflects a balance between treatment efficacy and toxicity. While typically, combination therapy improves response rate and time to progression compared with sequential monotherapy, it causes increased toxicity. Consequently, in cases of advanced cancer, emerging guidelines recommend sequential monotherapy, as a means to enhance quality of life. An alternative approach that could overcome nonspecific toxicity while retaining therapeutic efficacy, involves the combination of chemotherapy with targeted therapy. In the current study, we tested the hypothesis that combination therapy targeting survivin (BIRC5) and low-dose doxorubicin (Dox) will show enhanced therapeutic potential in the treatment of cancer, as compared to monotherapy with Dox. We demonstrate in both in vitro and in vivo models of breast cancer that combination therapy with a low dose of Dox and an anti-survivin siRNA nanodrug (MN-siBIRC5) is superior to mono-therapy with either low- or high-dose Dox alone. Importantly, therapeutic efficacy showed prominent sequence dependence. Induction of apoptosis was observed only when the cells were treated with Dox followed by MN-siBIRC5, whereas the reverse sequence abrogated the benefit of the drug combination. In vivo, confirmation of successful sequence dependent combination therapy was demonstrated in a murine xenograft model of breast cancer. Finally, to determine if the observed effect is not limited to breast cancer, we extended our studies to a murine xenograft model of pancreatic adenocarcinoma and found similar outcomes as shown for breast cancer.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Doxorrubicina/farmacología , Proteínas Inhibidoras de la Apoptosis/genética , Nanopartículas/administración & dosificación , ARN Interferente Pequeño/genética , Adenocarcinoma/genética , Animales , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Línea Celular Tumoral , Terapia Combinada/métodos , Femenino , Humanos , Ratones , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , SurvivinRESUMEN
We describe a technology for the profiling of miRNA expression in intact cells. The technology is based on sensor oligonucleotides that are cleavable, completely complementary to a target miRNA, and dual-labeled with a fluorescent dye and a quencher. Upon entering the cell, the sensor oligonucleotide binds its specific miRNA target through complementary base-pairing. This triggers assembly of the endogenous RNA Induced Silencing Complex (RISC) around the miRNA-sensor duplex and cleavage of the sensor oligonucleotide, resulting in separation between the dye and quencher, and a fluorescence turn-on. In the presented feasibility studies, we focus on a specific miRNA (miR-10b) implicated in breast cancer metastasis. Using a human breast adenocarcinoma cell line, we illustrate the application of this technology for miRNA detection with nanomolar sensitivity in both a cell-free system and intact cells.