Abstract

Apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) is an essential enzyme of the base excision repair (BER) pathway that maintains genome stability. It was identified as a pivotal factor favoring tumor progression, chemoresistance and cancer cell senescence through control of gene expression. APE1 is overexpressed and serum-secreted in hepatocellular carcinoma (HCC), non-small cell lung cancer (NSCLC) and colon cancer (CRC), representing a prognostic and predictive factor, and a promising non-invasive biomarker. Strategies directly targeting APE1 endonuclease activity in DNA repair, partly developed in our laboratories, led to the identification of inhibitors showing a potential therapeutic value, which are in clinical trials. Interestingly, evidence indicates novel roles of APE1 in RNA metabolism still not fully understood, including its activity in processing damaged RNA, including abasic (AP) and oxidized (ox) RNA, in chemoresistant phenotypes. Notably, we and others have shown that APE1 regulates oncomiRs maturation and AP- and ox-RNA decay. Furthermore, our preliminary data point out for a control role of APE1 in the expression and sorting of oncomiRs, within secreted extracellular vesicles (EVs), through interaction with proteins involved in: i) processing and sorting of microRNAs (miRs) (i.e. Drosha, hnRNPA2/B1, NPM1); ii) recognition of oxRNA (i.e. AUF1); iii) decay of nuclear RNA (i.e. MTR4), upon cisplatin (CDDP) and 5-fluorouracil (5FU) treatments. Even if miRs role in chemoresistance and their paracrine function through EVs is established, the mechanisms underlying their sorting and the control of their quality are totally unexplored. As well, information on damaged RNA decay processes are still lacking and could play a crucial part in chemoresistance processes.

Thanks to the experienced collaboration among the research units already focused on APE1, the present proposal aims to:

1. Identify and characterize oncomiRs regulated by APE1 during genotoxic stress and define their consensus binding motif using cellular, molecular and biochemical assays;
2. Identify novel APE1 protein partners able to recognize abasic and oxidized miRs involved in the decay process of damaged miRs through proteomics and cell and molecular assays;

Identify small molecules as potential drugs able to interfere with APE1-miRs, -AP-RNA -oxRNA complexes to sensitize cancer cells to chemotherapeutic agents;

These goals will be pursued using HCC, NSCLC, CRC cancer cell lines and CRC organoids, as promising non-animal models for drug screening, and through a combination of molecular and structural approaches. We will push ahead the application of single gene studies on APE1 by integrating various molecular approaches, multilevel network analyses and human cancer data repositories to develop novel anticancer strategies and innovative diagnostic/biotechnological tools.

Partenariato

• Università degli studi di Udine
• Consiglio Nazionale delle Ricerche
• Università degli Studi di Trento

Importo del progetto

Importo totale del progetto        Euro 85.870,40
Importo del progetto Uniud        Euro 72.891,00
Finanziamento Uniud                Euro 12.979,00

Durata

• Dal 04.02.2025
• Al 03.02.2027

Link

https://prin.mur.gov.it/