Objective: To investigate the role of mitogen activated protein kinase phosphatase-1 (MKP-1) in mediating acquired multidrug resistance in pancreatic adenocarcinoma cell line SW1990/Fu.
Methods: To detect MKP-1 mRNA expression, Northern blot analysis was carried out in well established drug resistant pancreatic adenocarcinoma cell line SW1990/Fu, SW1990 and MiaPaCa-2 cell lines. To further elucidate the exact role of MKP-1, Western blot hybridization was performed in these three cell lines.
Results: Northern blot analysis of total RNA isolated from SW1990/Fu, SW1990 and MiaPaCa-2 cell lines revealed the presence of the 2400 bp MKP-1 transcript 7 at relatively high levels in pancreatic cancer cell lines SW1990 and MiaPaCa-2. In the SW1990/Fu, the MKP-1 transcript was detectable at very low level. Densitometric analysis with normalization to 7S indicated that MKP-1 mRNA expression level was significantly decreased in SW1990/Fu in comparison with the parental and MiaPaCa-2 cell lines. MKP-1 protein expression level in SW1990/Fu detected by Western blot was coincident with mRNA level.
Conclusions: MKP-1 may be involved in acquired multidrug resistance in pancreatic adenocarcinoma, and we could hypothesized that alterations of intra-cellular transduction signal system acts as an important role in multidrug resistance of tumor cells.