Project description
Blocking DNA repair triggers anti-cancer immunity
The DNA mismatch repair (MMR) is a conserved biological pathway with a key role in maintaining genomic integrity by detecting and correcting errors that emerge during DNA replication. Intriguingly, cancers deficient in MMR respond well to immunotherapy and have an overall favourable outcome. The EU-funded TARGET project believes that the basis for this observation is that these types of cancer accumulate mutations, secreting neoantigens which trigger immunosurveillance. The consortium will test whether blocking MMR with drugs can provoke an anti-cancer immune response and halt tumour growth. Results will provide fundamental knowledge on anti-cancer immunity and will lay the foundation for the development of a new class of anti-cancer drugs
Objective
This project will test for the first time the hypothesis that therapeutic inactivation of DNA repair pathways in cancer cells can be exploited for patient benefit by reawakening an anti-tumor immune response.
Genomic instability and molecular heterogeneity, which occur in cancer cells with DNA repair deficiencies, fuel tumour progression and are associated with poor outcome. An exception is represented by Mismatch repair (MMR) deficient cancers as these tumours are exceedingly genetically heterogeneous but show favourable prognosis and remarkable response to immunotherapy.
The molecular basis for the clinical outcome of MMR deficient cancers has long remained a mystery. Only recently it has become apparent that their biological properties are associated with increased levels of mutations, which unleash adaptive immunity and trigger immunosurveillance.
We have reported that when MMR is impaired, cancers cells grow in immune-deficient mice but are unable to do so in immune competent animals. MMR inactivation increased the mutational burden and led to dynamic mutational profiles, resulting in persistent renewal of neoantigens and engagements of antigen-specific T cells.
These data suggest an unprecedented high risk-high gain approach: the pharmacological blockade of proteins involved in DNA-repair as an anticancer therapy. This unconventional strategy builds on the concept that the immune system can identify and selectively target tumor cells carrying DNA alterations.
Using in vitro and in vivo functional assays we will systematically assess whether and how inactivation of DNA repair genes provokes an immune response and restrict cancer growth. Notably, TARGET will discover and develop inhibitors of MMR and other DNA repair proteins that induce tumor immunity.
The identification of DNA repair pathways which, when disabled, reawaken the immune system will provide transformative knowledge and could lead to the development of an entirely new class of anticancer drugs.
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Funding Scheme
ERC-ADG - Advanced GrantHost institution
10124 Torino
Italy