Lung cancer is diagnosed late, has a 5 year survival of only 15%, and kills more people than colorectal, breast and prostate cancer combined. Less than 30% of lung cancers are resected and the majority of patients are treated with cisplatin and ionizing radiation (IR). We show that inhibition of DNA damage signaling by ATR kinase during treatment with cisplatin and IR is well-tolerated and leads to durable responses in mouse xenograft and genetic models of lung cancer. Quite unexpectedly, we show that in addition to potentiating DNA damage, two clinical ATR kinase inhibitors (ATRi?s), with unrelated structures, block expression of the immune checkpoint protein PD-L1 and increase presentation of MHC class I antigens in lung cancer cells after IR. Our finding that crosstalk exists between DNA damage signaling and immune checkpoints has not been described previously and is the focus of this proposal. Immune-inhibitory pathways, termed immune checkpoints, are coopted by tumor cells to evade cytotoxic immune cells. PD-1 is expressed on cytotoxic T cells and its ligand PD-L1 is upregulated in lung cancers. PD-L1 binding by PD-1 prevents the activation of cytotoxic T cells. Immune checkpoint blockade using anti-PD-L1 and anti-PD-1 antibodies restores anti-tumor immune responses and is emerging as an exciting lung cancer therapy. We propose that ATRi?s inhibit DNA repair and cell cycle checkpoints potentiating the DNA damage induced by cisplatin and IR while concurrently inhibiting PD-L1 expression and restoring anti-tumor immune responses. Our objective in this proposal is to define the mechanisms that connect DNA damage signaling and immune checkpoints. This objective will be accomplished by the following Specific Aims.
Aim 1 : To determine how ATRi?s inhibit PD-L1 expression in lung cancer cells after IR.
This aim will define the contribution of ATR, ATM, IRF-1, NF-?B and p53 to PD-L1 expression after IR.
Aim 2 : To determine how ATRi?s increase MHC class I expression on lung cancer cells after IR.
This aim will identify ATR, ATM, and p53 signaling that inhibits protein synthesis and MHC class I presentation after IR.
Aim 3 : To identify ATRi-induced PDL-1/PD-1 immune checkpoint blockade in lung cancer after IR.
This aim will identify ATRi-induced immune checkpoint blockade in lung cancer after IR. The outcomes of these Aims will identify mechanisms that connect DNA damage signaling to immune self- tolerance. This will define a novel therapeutic opportunity to use ATRi?s to potentiate the DNA damage induced by cisplatin and IR while concurrently inducing immune checkpoint blockade.

Public Health Relevance

Lung cancer acquires resistance mechanisms to therapies that target either DNA or activating mutations in a key signaling pathway and this inevitably leads to disease progression. We have discovered that ATRi?s block the expression of the immune checkpoint protein PD-L1 and increase presentation of MHC class I antigens. We propose that ATRi?s may combine and increase the efficacy of three treatment approaches. ATRi?s may potentiate the DNA damage induced by cisplatin and IR, which is standard of care for the majority of NSCLC patients, target cancer cells with increased ATR kinase signaling that is associated with replication stress, and concurrently induce immune checkpoint blockade. Successful completion of the experiments proposed in this application will determine whether ATR kinase inhibitors can deliver durable responses and a curative therapy to >4,350 people who die from lung cancer every day.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA204173-01A1
Application #
9236622
Study Section
Basic Mechanisms of Cancer Therapeutics Study Section (BMCT)
Program Officer
Ahmed, Mansoor M
Project Start
2017-01-01
Project End
2021-12-31
Budget Start
2017-01-01
Budget End
2017-12-31
Support Year
1
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Kiesel, Brian F; Scemama, Jonas; Parise, Robert A et al. (2017) LC-MS/MS assay for the quantitation of the ATR kinase inhibitor VX-970 in human plasma. J Pharm Biomed Anal 146:244-250
Zhang, Yaping; Hu, Kaiqiang; Beumer, Jan H et al. (2017) RAD-ADAPT: Software for modelling clonogenic assay data in radiation biology. DNA Repair (Amst) 52:24-30
Kiesel, Brian F; Shogan, Jeffrey C; Rachid, Madani et al. (2017) LC-MS/MS assay for the simultaneous quantitation of the ATM inhibitor AZ31 and the ATR inhibitor AZD6738 in mouse plasma. J Pharm Biomed Anal 138:158-165
Moiseeva, Tatiana; Hood, Brian; Schamus, Sandy et al. (2017) ATR kinase inhibition induces unscheduled origin firing through a Cdc7-dependent association between GINS and And-1. Nat Commun 8:1392