Role of the low molecular weight protein tyrosine phosphatase in the biogenesis of exosomes secreted by colon rectal cells

Abstract

In 2012 there were more than 14 million new cases of cancer worldwide with approximately 8.2 million deaths. In Brazil, it was estimated for the year 2015, 576 thousand new cases of this disease and from them, 33,000 cases would affect the colon and rectum. This tumor originates from any portion of the colon and rectum, and in 75% of cases it is confined to the colon wall and is curable by chemotherapy associated with surgery. However, around 15-20% of cases develop metastasis to other organs, and consequently, reducing the efficiency of current treatment protocols and patient survival. Recently, research groups have focused on the study of the mechanisms of chemotherapeutic resistance acquisition via vesicular structures called exosomes. Exosomes are no longer considered as reservoirs for unwanted proteins and came to be pointed out as important carriers of various biomolecules such as lipids, proteins and oncogenic factors. In addition, it has been proved that exosomes are important for cell-cell communication. Protein phosphatases, especially tyrosine phosphatase family, are presented as tumor suppressors, but the low molecular weight protein tyrosine phosphatase (LMWPTP) has been defined as oncogenic and involved in tumor aggressiveness and resistance to anticancer drugs. Thus, the general objective of this project is to examine if the level of LMWPTP expression is related to the biogenesis of exosomes in different colorectal cancer cell lines. Besides, we will evaluate if the LMWPTP can be one of the components carried by the exosomes.