RESUMO
PURPOSE: Fyn is a member of the Src family of kinases that we have previously shown to be overexpressed in prostate cancer. This study defines the biological impact of Fyn inhibition in cancer using a PC3 prostate cancer model. EXPERIMENTAL DESIGN: Fyn expression was suppressed in PC3 cells using an shRNA against Fyn (PC3/FYN-). Knockdown cells were characterized using standard growth curves and time-lapse video microscopy of wound assays and Dunn Chamber assays. Tissue microarray analysis was used to verify the physiologic relevance of the HGF/MET axis in human samples. Flank injections of nude mice were performed to assess in vivo growth characteristics. RESULTS: HGF was found to be sufficient to drive Fyn-mediated events. Compared to control transductants (PC3/Ctrl), PC3/FYN- showed a 21% decrease in growth at 4 days (P = 0.05). PC3/FYN- cells were 34% longer than control cells (P = 0.018) with 50% increase in overall surface area (P < 0.001). Furthermore, when placed in a gradient of HGF, PC3/FYN- cells showed impaired directed chemotaxis down an HGF gradient in comparison to PC3/Ctrl (P = 0.001) despite a 41% increase in cellular movement speed. In vivo studies showed 66% difference of PC3/FYN- cell growth at 8 weeks using bidimensional measurements (P = 0.002). CONCLUSIONS: Fyn plays an important role in prostate cancer biology by facilitating cellular growth and by regulating directed chemotaxis-a key component of metastasis. This finding bears particular translational importance when studying the effect of Fyn inhibition in human subjects.
Assuntos
Forma Celular , Fator de Crescimento de Hepatócito/metabolismo , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas c-fyn/fisiologia , Proteínas Proto-Oncogênicas c-met/metabolismo , Receptores de Fatores de Crescimento/metabolismo , Tropismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Forma Celular/efeitos dos fármacos , Forma Celular/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Fator de Crescimento de Hepatócito/genética , Humanos , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-fyn/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-fyn/genética , Proteínas Proto-Oncogênicas c-fyn/metabolismo , Proteínas Proto-Oncogênicas c-met/genética , RNA Interferente Pequeno/farmacologia , Receptores de Fatores de Crescimento/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Tropismo/efeitos dos fármacos , Tropismo/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Intestinal absorption rate constants of amoxicillin, ampicillin, epicillin, cyclacillin and azidocillin, by means of a static in situ intestinal perfusion method has been estimated. Luminal remaining antibiotic concentrations were determined using a standard microbiological technique. In order to establish statistically better absorption kinetics, five dose levels were used, ranging from 10 to 1000 micrograms/ml, and first order, Michaelis-Menten and combined first-order and Michaelis-Menten differential model equations were fitted to experimental data found for each antibiotic. According to the AIC test, the best equation for absorption kinetics was selected. Amoxicillin and ampicillin absorption mechanisms were better described by combined kinetics, while for cyclacillin and epicillin the most probable kinetics was that of Michaelis-Menten. For azidocillin, the only non-aminopenicillin component of this series, first order kinetics should be statistically selected.
