ABSTRACT
Objective Stathmin, a microtubule-destabilizing protein , has high expression in esophageal squamous cell carci-noma(ESCC), while taxol is a common chemotherapy microtubule-targeted drug for esophageal cancer .This study aimed to investigate the impact of stathmin expression and its influence on taxol sensitivity in ESCC . Methods We established 2 cell models with ST-MN1 gene overexpression in KYSE 510 and KYSE 170 cell lines, including KYSE 510-Stathmin, KYSE 170-Stathmin, KYSE 510-Control and KYSE 170-Control.MTT assay and colony formation were applied to compare the taxol sensitivity between experimental group and control group .Flow cytometry was used to measure the apoptosis of KYSE 510-Stathmin and KYSE 510-Control after taxol treatment.Western blot was used to test the changes of related factors to apoptosis and autophagy . Results ①Stathmin protein ex-pressions in KYSE 510-Stathmin and KYSE 170-Stathmin cells were higher than those of control cells (P<0.01).② The percentages of inhibition were significantly decreased in KYSE 510-Stathmin and KYSE 170-Stathmin cells 24 h after 50, 100,250 nmol/L taxol treat-ment compared with KYSE 510-Stathmin cells(P <0.01).③The percentages of inhibition were significantly reduced in KYSE 510-Stathmin and KYSE 170-Stathmin cells after 250 nM taxol treatment for 24, 48, 60 h (P<0.01).④After taxol treatment,the number of colony formation in KYSE 510-Stathmin cells was higher com-pared with KYSE 510-Control cells (P<0.01).⑤The percentage of cell apoptosis in KYSE 510-Stathmin was significantly lower than that of KYSE 510-Control cells by flow cytometry (11.90%±0.78%vs 29.63%±3.26%, P<0.05).Western blot showed the ap-optosis of associated proteins such as the activation of Caspase 8 and Caspas9. Conclusion The result indicates that overexpression of stathmin inhibits taxol sensitivity in ESCC cell lines .
ABSTRACT
Objective To explore the role of ubiquitin-proteasome pathway for the gelsolin protein degradation in pancreatic cancer.Methods Pancreatic cancer cell lines BxPC-3 and PANC-1 were first treated with specific 26s proteasome inhibitor lactacystin.Immunoblots of cell lysates were probed for gelsolin expression.To determine whether gelsolin was conjugated to ubiquitin,proteins extracted from the cells with or without lactacystin were immunoprecipitated with anti-gelsolin antibody,followed by Western blot analysis.Results The expression of gelsolin protein increased obviously after treatment with lactacystin in BxPC-3 cells for 12 h.Using anti-gelsolin antibody to immunoprecipitate gelsolin protein and followed by Western blot using anti-ubiquitin monoclonal antibody,it was found that inhibition of proteasome pathway by lactacystin resulted in accumulation of ubiquitylated forms of gelsolin protein.In PANC-1 cell line,there was no significant changes of gelsolin after treatment with lactacystin.Conclusion Ubiquitin-proteasome dependent degradation may be an important regulatory mechanism for gelsolin down-regulation in pancreatic cancer cells.