4B). This finding was mirrored in BHKCFTR cells (Fig. 4C, D). This observation was not an artifact induced by CS exposure, such as CS interfering with CFTR-antibody binding, since www.selleckchem.com/products/Gemcitabine-Hydrochloride(Gemzar).html CFTR was detected equally well after CS exposure at 4��C and following exposure to plasma membrane vesicles containing CFTR (Fig. 4G, H). The apparent reduction in CFTR solubility was not affected by inhibition of CFTR internalization (MG132) or by proteosomal inhibition (ALLN and MG132; Fig. 4E, F), and CFTR did not appear to associate with lysosomes (Fig. 5). We also observed a significant decrease in detergent solubility of CFTR following CS exposure, with a high concentration of SDS being required for CFTR solubilization in both BHKCFTR cells and CALU3 airway epithelia, (Fig. 6).
Interestingly, prelabeled CFTR internalized to a perinuclear compartment post-CS exposure, where it remained for 24 h (Fig. 7). CFTR appeared to closely associate with vimentin, an intermediate filament protein that has previously been shown to play a role in, and be an indicator of, aggresome formation (19). After acute CS exposure, the inhibition of CFTR waned with time, and new CFTR was identified in the plasma membrane within ~60 min after CS exposure (Fig. 3E). To investigate the source of this recovered CFTR, we pretreated cells with the protein trafficking inhibitor brefeldin A. This compound prevented the recovery of plasma membrane CFTR after a single CS exposure (Fig. 3). Since CS-internalized CFTR remained in the perinuclear
Pancreatic cancer is one of the most difficult cancers to treat although it accounts for only 3% of all cancers.
Despite multiple clinical trials with new chemotherapeutic agents, over the past 25 years the 5-year survival rate of 5%, and median survival of 6 months has largely remained unchanged. The median survival is about 6 months [1], [2]. One reason for the poor survival of pancreatic cancer is the insensitivity to most conventional therapies including chemotherapy and radiotherapy [3]. Thus, novel and efficacious therapeutic agents or regimens are urgently needed for treatment of pancreatic cancer. Apoptosis is an essential part of mechanisms that maintain normal tissue homeostasis [4]. Deregulation of the apoptosis machinery and evasion of apoptosis is a general mechanism in cancer. Most chemotherapies act by the induction of apoptosis.
Therefore, evasion of apoptosis is mainly responsible for the insufficiency of current therapies [2], [5]. It is well known that cells can die of apoptosis primarily through the extrinsic death receptor-induced pathway and/or the intrinsic mitochondria-mediated pathway [6]. The activation of the extrinsic death receptor-mediated apoptotic pathway involves ligation of a death ligand (e.g., tumor necrosis factor-related apoptosis-inducing GSK-3 ligand; TRAIL) with its corresponding cell surface death receptor(s) or aggregation (e.g.