Extracellular vesicles in colorectal cancer cells: the unconventional secretion of low molecular weight protein tyrosine phosphatase and action in human fibroblasts

Author(s)

Stefano Piatto Clerici

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2021-09-01

Examining board members

Carmen Veríssima Ferreira; Patricia Xander Batista; Aline Mara dos Santos; Eduardo Galembeck; Gustavo Facchini

• Advisor: Carmen Veríssima Ferreira

Abstract

Colorectal cancer (CRC) was the second type of malignant neoplasm that most affected women and the third most prevalent in men worldwide in 2020. When early detected, CRC has a good prognosis, and the tumor mass is limited to the lumen of the colon or rectum. However, around 15-20% of CRC cases evolve to metastases spreading to other organs thus reducing the efficiency of therapeutic treatments contributing to a low survival rate for patients. Tumor progression is a complex process and in the molecular context, several aspects still need to be clarified. Low molecular weight protein tyrosine phosphatase (LMWPTP) participates in the metastasis process and resistance to chemotherapy in different types of tumors, including solid and hematopoietic. In the context of CRC, LMWPTP is associated with the malignant evolution of the disease and with a less favorable prognosis for patients. Research groups have focused on studying the contribution of extracellular vesicles ("EVs") in the process of tumor education, since EVs have come to be considered important carrier structures for several biomolecules. The main hypothesis of the present work is to evaluate whether LMWPTP is released via CRC-derived EVs and whether these released EVs can interact with human fibroblasts to modulate them. Through classical EVs characterization assays, it was observed that morphologically, in size and specific protein markers, that the EVs secreted by HCT116 and HT29 cells are small extracellular vesicles (sEVs) the concentration is significantly higher in the HT29 cell line that has higher protein levels of LMWPTP and Src kinase compared to HCT116. Furthermore, it was observed that HT29-derived sEVs have protein levels of LMWPTP. In a second moment, it was observed that human fibroblasts can internalize the sEVs secreted by both HCT116 and HT29 cells. HCT116-derived and HT29-derived sEVs can activate normal human fibroblasts into CAFs, represented by a high amount of the ?-SMA marker. In terms of biological function, both HCT116 and HT29-derived sEVS induced migratory capacity in activated fibroblasts in a molecular mechanism signaling dependent on Rho (Ras homolog protein), FAK (fokal adhesion kinase) and Src phosphorylation levels. In conclusion, the data suggested an unconventional way of LMWPTP secretion via HT29-derived sEVs in addition to that, the sEVs secreted by CRC cells can educate normal human fibroblasts to activate them in a state that confers migratory capacity (AU)

• FAPESP's process: 18/03593-6 - Tumor-educated platelets and metastasis: relevance of LMWPTP and extracellular vesicles in Colorectal Cancer
• Grantee: Stefano Piatto Clerici
• Support Opportunities: Scholarships in Brazil - Doctorate