Objective To compare the proteome difference between multiple myeloma cell line U266 cells treated and untreated with PS-341, to investigate the potential drug targets, and to provide theoretical evidence for clinical therapy of multiple myeloma. Methods Two-dimensional gel electrophoresis (2-DE) was performed to separate proteins from treated and untreated U266 cells with proteasome inhibitor PS-341. ImageMaster 2D Platinum software was used to analyze 2-DE image, and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) was used to identify the differentially expressed proteins. The expression levels of differential protein BAG-2 in the 2 groups of U266 cells lines were detected by Western blot. Results The 2-DE reference pattern of treated and untreated U266 cells with PS-341 was established. A total of 31 differential proteins were identified by MALDI-TOF-MS, 27 of which were down-regulated after PS-341 treatment. The differential expression level of BAG-2 in the 2 groups of U266 cells was confirmed by Western blot. Conclusion Some down-regulated proteins may be the potential drug targets of proteasome inhibitor PS-341.

BACKGROUND:Embryonic stem cel s have the capacity of multi-differentiation potential, and have been utilized for the therapy of acute liver injury. However, the migration and proliferation of embryonic stem cel s after transplantation remains not wel characterized.
OBJECTIVE:To track the transplanted embryonic stem cel s in repairing acute liver injury by bioluminescence imaging technology.
METHODS:Murine embryonic stem cel s (D3) were transducted with a construct composed of firefly luciferase, monomeric red fluorescence protein and herpes simplex virus truncated thymidine kinase triple fusion reporter genes by lentivirus system. Stable D3 embryonic stem cel s integrating three report genes were screened. The undifferentiated embryonic stem cel s or differentiated embryonic stem cel s from the 6-day-old embryoid body were transplanted into acute liver injury model of SV129 mouse through spleen, and the transplanted cel s were monitored by bioluminescence imaging technology.
RESULTS AND CONCLUSION:Reverse transcription PCR results showed that the expression level of Oct-4 and Nanog was not affected in embryonic stem cel s transducted with triple fusion reporter gene compared with wild-type embryonic stem cel s. The migration process of transplanted cel s was visualized by bioluminescence imaging technology. Teratomas were found in both triple fusion-embryonic stem cel s treatment group and triple fusion-embryoid body cel s treatment group at liver, and the teratoma formation could be suppressed by ganciclovir administration because ganciclovir can react with herpes simplex virus truncated thymidine kinase and trigger cel necrosis process. Histological analysis showed that teratomas comprised tissues from al three germ layers. These results demonstrate that triple gene fusion does not affect differentiation potential of embryonic stem cel s and it is risky to utilize embryonic stem cel s for cel therapy, because it affects repair of liver injury. The therapy strategy requires further improvement and real-time visualizing of embryonic stem cel s in vivo is absolutely necessary.