RODRIGO ESAKI TAMURA
Projetos de Pesquisa
Unidades Organizacionais
LIM/24 - Laboratório de Oncologia Experimental, Hospital das Clínicas, Faculdade de Medicina
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
- S6Ks isoforms contribute to viability, migration, docetaxel resistance and tumor formation of prostate cancer cells(2016) AMARAL, Camila L.; FREITAS, Lidia B.; TAMURA, Rodrigo E.; TAVARES, Mariana R.; PAVAN, Isadora C. B.; BAJGELMAN, Marcio C.; SIMABUCO, Fernando M.Background: The S6 Kinase (S6K) proteins are some of the main downstream effectors of the mammalian Target Of Rapamycin (mTOR) and act as key regulators of protein synthesis and cell growth. S6K is overexpressed in a variety of human tumors and is correlated to poor prognosis in prostate cancer. Due to the current urgency to identify factors involved in prostate cancer progression, we aimed to reveal the cellular functions of three S6K isoforms-p70-S6K1, p85-S6K1 and p54-S6K2-in prostate cancer, as well as their potential as therapeutic targets. Methods: In this study we performed S6K knockdown and overexpression and investigated its role in prostate cancer cell proliferation, colony formation, viability, migration and resistance to docetaxel treatment. In addition, we measured tumor growth in Nude mice injected with PC3 cells overexpressing S6K isoforms and tested the efficacy of a new available S6K1 inhibitor in vitro. Results: S6Ks overexpression enhanced PC3-luc cell line viability, migration, resistance to docetaxel and tumor formation in Nude mice. Only S6K2 knockdown rendered prostate cancer cells more sensitive to docetaxel. S6K1 inhibitor PF-4708671 was particularly effective for reducing migration and proliferation of PC3 cell line. Conclusions: These findings demonstrate that S6Ks play an important role in prostate cancer progression, enhancing cell viability, migration and chemotherapy resistance, and place both S6K1 and S6K2 as a potential targets in advanced prostate cancer. We also provide evidence that S6K1 inhibitor PF-4708671 may be considered as a potential drug for prostate cancer treatment.
- Transcriptional effects of 1,25 dihydroxyvitamin D-3 physiological and supra-physiological concentrations in breast cancer organotypic culture(2013) MILANI, Cintia; KATAYAMA, Maria Lucia Hirata; LYRA, Eduardo Carneiro de; WELSH, JoEllen; CAMPOS, Laura Tojeiro; BRENTANI, M. Mitzi; MACIEL, Maria do Socorro; ROELA, Rosimeire Aparecida; VALLE, Paulo Roberto del; GOES, Joao Carlos Guedes Sampaio; NONOGAKI, Suely; TAMURA, Rodrigo Esaki; FOLGUEIRA, Maria Aparecida Azevedo KoikeBackground: Vitamin D transcriptional effects were linked to tumor growth control, however, the hormone targets were determined in cell cultures exposed to supra physiological concentrations of 1,25(OH)(2)D-3 (50-100nM). Our aim was to evaluate the transcriptional effects of 1,25(OH)(2)D-3 in a more physiological model of breast cancer, consisting of fresh tumor slices exposed to 1,25(OH)(2)D-3 at concentrations that can be attained in vivo. Methods: Tumor samples from post-menopausal breast cancer patients were sliced and cultured for 24 hours with or without 1,25(OH)(2)D-3 0.5nM or 100nM. Gene expression was analyzed by microarray (SAM paired analysis, FDR <= 0.1) or RT-qPCR (p <= 0.05, Friedman/Wilcoxon test). Expression of candidate genes was then evaluated in mammary epithelial/breast cancer lineages and cancer associated fibroblasts (CAFs), exposed or not to 1,25(OH)(2)D-3 0.5nM, using RT-qPCR, western blot or immunocytochemistry. Results: 1,25(OH)(2)D-3 0.5nM or 100nM effects were evaluated in five tumor samples by microarray and seven and 136 genes, respectively, were up-regulated. There was an enrichment of genes containing transcription factor binding sites for the vitamin D receptor (VDR) in samples exposed to 1,25(OH)(2)D-3 near physiological concentration. Genes up-modulated by both 1,25(OH)(2)D-3 concentrations were CYP24A1, DPP4, CA2, EFTUD1, TKTL1, KCNK3. Expression of candidate genes was subsequently evaluated in another 16 samples by RT-qPCR and up-regulation of CYP24A1, DPP4 and CA2 by 1,25(OH)(2)D-3 was confirmed. To evaluate whether the transcripitonal targets of 1,25(OH)(2)D-3 0.5nM were restricted to the epithelial or stromal compartments, gene expression was examined in HB4A, C5.4, SKBR3, MDA-MB231, MCF-7 lineages and CAFs, using RT-qPCR. In epithelial cells, there was a clear induction of CYP24A1, CA2, CD14 and IL1RL1. In fibroblasts, in addition to CYP24A1 induction, there was a trend towards up-regulation of CA2, IL1RL1, and DPP4. A higher protein expression of CD14 in epithelial cells and CA2 and DPP4 in CAFs exposed to 1,25(OH)(2)D-3 0.5nM was detected. (Continued on next page) (Continued from previous page) Conclusions: In breast cancer specimens a short period of 1,25(OH)(2)D-3 exposure at near physiological concentration modestly activates the hormone transcriptional pathway. Induction of CYP24A1, CA2, DPP4, IL1RL1 expression appears to reflect 1,25(OH)(2)D-3 effects in epithelial as well as stromal cells, however, induction of CD14 expression is likely restricted to the epithelial compartment.