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Objective@#To explore new multidrug resistant genes of pancreatic cancer by establishment and characterization of chemo-resistant cell lines.@*Methods@#The cisplatin-resistant cell line JF305/CDDP and the gemcitabine-resistant cell line PANC-1/GEM were induced by high-dose intermittent treatment. CCK-8 assay was used to detect the 50% inhibiting concentration (IC50), drug resistance index (R), cross-resistance, and growth difference of different cells. The changes of cell cycle and migration ability of drug-resistant cells were determined by flow cytometry and transwell assay, respectively. And then real-time fluorescence quantitative PCR was used to detect the expression of multidrug resistance-related genes.@*Results@#The drug resistance indexes of JF305/CDDP and PANC-1/GEM were 15.3 and 27.31, respectively, and there was cross-resistance. Compared with the parental cells, the proliferation rate of JF305/CDDP was decreased by 40% on the fourth day (P<0.05); the proportion of S phase was decreased from (45±2)% to (30±2)% (P<0.05), and the migration ability was enhanced from (32 ±1) cells per field to (158±5) cells per field (P<0.01). The expression of multidrug resistance-related genes MRP2, MDR1, LRP and MSX2 was increased in JF305/CDDP cells (P<0.05). Knockdown of MSX2 in JF305 cells reduced the expression of MRP2, whereas overexpression of MSX2 in PANC-1 cells upregulated MRP2 level (P<0.05).@*Conclusions@#Two stable multidrug resistant cell lines of pancreatic cancer, JF305/CDDP and PANC-1/GEM, were successfully established. MSX2 might be a new drug resistance related gene in pancreatic cancer cells by up-regulation of MRP2 expression.
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TNF-alpha, a proinflammatory cytokine, inhibits osteoblast differentiation under diverse inflammatory conditions; however, the underlying mechanisms in terms of the TNF-alpha signaling pathway remain unclear. In this study, we examined the role of Msx2 in TNF-alpha-mediated inhibition of alkaline phosphatase (ALP) expression and the signaling pathways involved. TNF-alpha down-regulated ALP expression induced by bone morphogenetic protein 2 (BMP2) in C2C12 and Runx2-/- calvarial cells. Over-expression of Msx2 suppressed BMP2-induced ALP expression. Furthermore, TNF-alpha induced Msx2 expression, and the knockdown of Msx2 by small interfering RNAs rescued ALP expression, which was inhibited by TNF-alpha. TNF-alpha activated the NF-kappaB and the JNK pathways. Inhibition of NF-kappaB or JNK activation reduced the inhibitory effect of TNF-alpha on ALP expression, whereas TNF-alpha-induced Msx2 expression was only suppressed by the inhibition of the NF-kappaB pathway. Taken together, these results indicate that Msx2 mediates the inhibitory action of TNF-alpha on BMP2-regulated osteoblast differentiation and that the TNF-alpha-activated NF-kappaB pathway is responsible for Msx2 induction.
Asunto(s)
Animales , Ratones , Fosfatasa Alcalina/genética , Animales Recién Nacidos , Proteína Morfogenética Ósea 2/farmacología , Técnicas de Cultivo de Célula , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Regulación hacia Abajo/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas de Homeodominio/antagonistas & inhibidores , Ratones Endogámicos ICR , Ratones Transgénicos , Osteoblastos/efectos de los fármacos , ARN Interferente Pequeño/farmacología , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Objective To investigate the expression of homeobox gene MSX-2 during cranial suture fusion of SD rats and discuss its significance. Methods SD rats aged 1, 2, 5, 8, 12, 15, 18, 22, 30 and 45 days were selected, and immunohistochemistry and Real-time PCR were employed to localize and quantify the expression of MSX-2 in different regions of cranial sutures. Results MSX-2 expressed in calvarial suture tissues including the extreme ends of the osteogenic fronts and the underlying dura mater. The expression of MSX-2 was low in posterior frontal suture (PF) and sagittal suture (SAG) from postnatal day 1 to day 8 before the initiation of suture fusion, while it was higher in PF than in SAG from postnatal day 12 to day 22 after the initiation of PF suture fusion. The expression of MSX-2 significantly declined in PF and was moderately higher than that in SAG from postnatal day 30 to day 45 after the initiation of suture fusion. Conclusion There is different expression of MSX-2 in PF and SAG during different suture fusion periods, which suggests the expression of MSX-2 may participate in the regulation of cranial bone development and the fusion of cranial sutures.