RESUMEN
The phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway is frequently hyper-activated upon vemurafenib treatment of melanoma. We have here investigated the relationship between SRY-box 10 (SOX10), forkhead box 3 (FOXD3) and microphthalmia-associated transcription factor (MITF) in the regulation of the receptor tyrosine-protein kinase ERBB3, and its cognate ligand neuregulin 1-beta (NRG1-beta). We found that both NRG1-beta and ERBB3 mRNA levels were elevated as a consequence of MITF depletion, induced by either vemurafenib or MITF small interfering RNA (siRNA) treatment. Elevation of ERBB3 receptor expression after MITF depletion caused increased activation of the PI3K pathway in the presence of NRG1-beta ligand. Together, our results suggest that MITF may play a role in the development of acquired drug resistance through hyper-activation of the PI3K pathway.
Asunto(s)
Melanoma/tratamiento farmacológico , Factor de Transcripción Asociado a Microftalmía/fisiología , Neurregulina-1/análisis , Receptor ErbB-3/análisis , Línea Celular Tumoral , Factores de Transcripción Forkhead/análisis , Humanos , Indoles/farmacología , Indoles/uso terapéutico , Melanoma/metabolismo , Factor de Transcripción Asociado a Microftalmía/análisis , Fosfatidilinositol 3-Quinasas/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factores de Transcripción SOXE/análisis , Transducción de Señal/fisiología , Sulfonamidas/farmacología , Sulfonamidas/uso terapéutico , VemurafenibRESUMEN
Photochemical internalization (PCI) is a technology based on a photosensitizer that photochemically destabilizes endosomal membranes after illumination, resulting in the release of endocytosed material into the cytosol. In this study, we investigated the potential of using polyethylenimine (PEI) for light-controlled delivery of small interfering RNA (siRNA) molecules via the endocytic pathway. PEI formulations with different molecular weights (MW) and chemical forms (linear [L]/branched [B]) were investigated for their capacity to deliver siRNA molecules with or without PCI at variable nitrogen/phosphorus (N/P) ratios and illumination doses. By targeting the S100A4 gene in an osteosarcoma cell model system, potent gene silencing was observed in samples treated with PCI compared with samples not treated with PCI. The effect of light-controlled gene silencing was dependent on several factors, including light-doses and MW, chemical form, as well as on the N/P ratio of the PEI formulations. This study demonstrates the first success in using PEI formulations as siRNA carriers for light-controlled gene silencing with the objective of future use in in vivo applications.
