Stalled Replication Fork Protection Defects as a Predictor of Therapeutic Response
Abstract
The major goals of this award are to study prevalence and mechanisms of stalled replication fork protection defects in high grade serous ovarian cancer (HGSC) using patient derived organoid models. The goals of the three Aims included generating and characterizing the organoids, profiling the DNA damage repair capacity of the organoids, and determining if there is synergy between DNA damage repair defect therapies and immune therapies. Thus far we have generated 50 HGSC organoid cultures and validated them as being matches to their parent tumors. We profiled the DNA damage repair capacity of these cultures, demonstrated that the majority were proficient in homologous recombination and some deficient in stalled replication fork protection, and that these fork protection defects correlated with sensitivity to specific DNA damage repair therapies. We have tested for activation of the replication stress response in various tumors after single or combination DNA damage repair therapies. We have not identified a common mechanism within ATR signaling which is an overarching signaling pathway in replication stress. We have identified the bromodomain containing protein BRD1 as possibly being important in the replication stress response in HGSC. We continue to work up the mechanism of action of BRD1 and have now found it to be critical in the HGSC replication stress response. It is a relevant therapeutic target. We immune profiled multiple parent tumors and matched organoid/immune cell co-cultures by flow cytometry and one also by single cell RNA sequencing and demonstrated that the organoid co-cultures are accurate models of the parent tumors. We performed flow cytometry and ELISA functional analyses on these co-cultures and found that immunotherapies do induce an immune response in these cultures and were able to determine that BRD1 depletion by some of these immune therapies is the mechanism by which these therapies bring intra-tumoral immune cells back from exhaustion.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2023
- Accession Number
- AD1208916
Entities
People
- Sarah Hill
Organizations
- Dana–Farber Cancer Institute