Validation of CTP:phosphoethanolamine cytidylyltransferase enzyme and ethanolamine transport as new targets for the rational development of new drugs in Non-Small Cell Lung Cancer treatment.

Author(s)

Sarah Fernandes Teixeira

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2020-09-10

Examining board members

Emer Suavinho Ferro; Jacy Gameiro; João Agostinho Machado Neto; Nayara Gusmão Tessarollo

• Advisor: Emer Suavinho Ferro; Adilson Kleber Ferreira

Abstract

The research and development of new drugs has grown for decades, however, the arrival of new drugs in therapy suffers from the barriers of target validation. In this context, therapeutics for critical diseases remain unresolved, including for lung carcinoma (LC). LC is the cancer with the highest morbidity and mortality worldwide, with around eighty percent of cases diagnosed as non-small cell lung cancer (NSCLC). Our group works on the development of new drugs capable of interfering in the production of phosphatidylethanolamine (PE) as an innovative strategy for the treatment of NSCLC. This focus is due to the increase of this phospholipid in NSCLC and its relationship with tumor progression. There are two ways to reduce the production of PE: 1) reduce the activity of the rate-limiting CTP enzyme: phosphoethanolamine-cytidylyl transferase (Pcyt2), and 2) reduce the cellular supply of ethanolamine, which is the substrate of all PE production routes. Thus, this work evaluated in vitro and in vivo importance of Pcyt2 enzyme activity and ethanolamine transport, in NSCLC models. The effect of Pcyt2 inhibition was evaluated both against the meclizine inhibitor and using A549 and LL2/LC1 cells with the deletion of the PCYT2 (KO) gene. Inhibition of ethanolamine transport was assessed using the DL-1-amino-2-propanol inhibitor. Concomitant inhibition of Pcyt2 and ethanolamine transport reduced the viability of A549 cells, by mechanism independent of apoptosis. The meclizine mechanism of action was suggested to be associated with mitochondrial damage. A549 KO cells show decreased cell proliferation, possibly associated with a reduction in phosphorylated Rb protein, resulting from the action of phosphorylated p21 and p53. The transport of PE and ethanolamine were shown to be essential for cell proliferation, only in culture of wild-type A549 cells expressing Pcyt2. LL2/LC1 KO cells demanded longer time for the formation of tumors in mice, corroborating the importance of Pcyt2 for tumor development. Taken together, these data suggested the potential of the Pcyt2 enzyme and ethanolamine transport as targets for cytostatic agents in the treatment of NSCLC. (AU)

• FAPESP's process: 16/09392-7 - Validation of CTP:phosphoethanolamine cytidylyltransferase enzyme and ethanolamine transport as new targets for the rational development of new drugs in Non-Small Cell Lung Cancer treatment
• Grantee: Sarah Fernandes Teixeira
• Support Opportunities: Scholarships in Brazil - Doctorate