Expression of two endoplasmic reticulum stress markers, GRP78 and GADD153, is involved in the mechanism of action of the Amblyomin-X

Abstract

Introduction: A cDNA library of the A. cajennense tick salivary glands was constructed and used to identify a gene encoding a Kunitz-type protease inhibitor. A recombinant protein, named Amblyomin-X was over expressed in E. coli. The expressed protein is able to promote apoptosis in murine renal adenocarcinoma (RENCA), decreased proteasomal activity and increased pool of poly-ubiquitinylated proteins in some tumor cell lines, suggesting an endoplasmic reticulum (ER)-stress. However, the mechanistic effects of this protein are still unclear. Objective: Evaluate the involvement of ER-stress in tumor cells treated or not with Amblyomin-X.

Methods: To evaluate two markers of the ER-stress, GRP78 and GADD153, the genic expression was perfomed by ABI 7500 Real Time PCR System (Life Technologies) using forward and reverse specific genes primers and analysis for Western Blot with specific monoclonal antibodies were performed.

Results: RENCA cells treated with Amblyomin-X showed a modest effect in genes related to ER-stress, but significant differences in protein expression was observed.

Conclusion: The results suggest that ER-stress is involved in this process pro-apoptotic of the Amblyomin-X.