Using a glycomic technique, has allowed the iden tification of a quantity of tum

These findings indicate that DHA induced some kind of protective, pro survival autophagy increasing the resistance of the cancer cells against DHA therapy. The induction of autophagy was independent on Atg5. This increase in cell death via au tophagy inhibition would lead to the inhibition of tumor growth. Treatment with DHA activates 17-AAG 臨床試験 JNK and beclin 1 in pancreatic cancer cells DHA activates mitogen activated protein kinase signaling pathways in a number of cell types. To study the MAPKJNK signaling pathway in DHA induced autophagy, we first measured JNK ac tivation by DHA. DHA stimulated JNK phosphoryl ation in a dose and time dependent manner in the two cell lines. The induction of autophagy by DHA was con firmed previously. To determine if DHA upregulated Beclin 1 expression in BxPC 3 and PANC 1 cells, Beclin 1 protein expression was measured.

Immuno blotting revealed dose and time dependent increases in Beclin 1 expression in cells exposed to DHA. These findings demonstrated that treat ment with DHA activates JNK and Beclin 1 in both pancreatic cancer cell lines in a dose and time dependent manner. Up regulation of JNK expression following 17-DMAG 溶解度 DHA treatment depends on ROS JNK pathway over activation is crucial to many pro cesses leading to cell death, including chronic and acute was decreased in the cells pretreated with NAC, and this decreased JNK activation was related to the inhib ition of ROS formation. These results indicate that JNK ex pression following DHA treatment depends on ROS.

Inhibition of JNK expression down regulates beclin 1 and reduces autophagy A66 構造 To further assess the role of JNK in DHA induced au tophagy, cells were pretreated with SP600125 for 1 h, and were then exposed to DHA. In contrast to DHA alone, SP600125 pretreatment blocked the increase in LC3 II induced by DHA. Furthermore, SP600125 treatment decreased the punctate foci of LC3 in the cytoplasm. To determine if JNK activation is required for Beclin 1 expression in the context of DHA induced autophagy, JNK expression was knocked down using a siRNA di rected against JNK12. siRNA transient transfection down regulated JNK. More importantly, siRNA mediated JNK down regulation prevented the DHA induced up regulation of Beclin 1 protein in addition to efficiently inhibiting the level of JNK phos phorylation in pancreatic cancer cells.

These findings suggest that JNK could be directly involved in the DHA induced increased Beclin 1 expression. oxidative stress. Although ROS can increase JNK signal ing via the activation of upstream kinases or the inacti vation of phosphatases, other unknown mechanisms are likely to contribute to ROS induced JNK increases in pancreatic cancer cells. To exclude the possibility that other mechanisms were responsible for our observa tions, we measured ROS levels in response to DHA. ROS were increased after DHA treatment and did not differ between the two tested cell lines. To further determine whether DHA treatment requires JNK activation to generate ROS, we pre treated BxPC 3 cells with SP600125 for 1 h, be fore exposing them to DHA. In contrast to DHA treatment alone, SP600125 pretreatment prevented alterations in ROS levels.