PDL1 Regulation by p53 via miR-34

• Published in: JNCI : Journal of the National Cancer Institute Vol. 108; no. 1; p. 1
• Main Authors: Cortez, Maria Angelica, Ivan, Cristina, Valdecanas, David, Wang, Xiaohong, Peltier, Heidi J., Ye, Yuping, Araujo, Luiz, Carbone, David P., Shilo, Konstantin, Giri, Dipak K, Kelnar, Kevin, Martin, Desiree, Komaki, Ritsuko, Gomez, Daniel R., Krishnan, Sunil, Calin, George A., Bader, Andreas G., Welsh, James W.
• Format: Journal Article
• Language: English
• Published: United States Oxford Publishing Limited (England) 01.01.2016; Oxford University Press
• Subjects: Adenocarcinoma - metabolism; Adenocarcinoma of Lung; Animals; B7-H1 Antigen - metabolism; Carcinoma, Non-Small-Cell Lung - drug therapy; Carcinoma, Non-Small-Cell Lung - metabolism; Carcinoma, Non-Small-Cell Lung - radiotherapy; CD8 Antigens - metabolism; Cell Line, Tumor; Cell Proliferation; Cells; Clinical trials; Gene Expression Regulation, Neoplastic - drug effects; Gene Expression Regulation, Neoplastic - radiation effects; Liposomes; Lung cancer; Lung Neoplasms - drug therapy; Lung Neoplasms - metabolism; Lung Neoplasms - radiotherapy; Mice; MicroRNAs - administration & dosage; MicroRNAs - metabolism; Neoplasms, Experimental - metabolism; Protein expression; Radiation; Signal transduction; Tumor Suppressor Protein p53 - metabolism
• ISSN: 0027-8874; 1460-2105; 1460-2105
• DOI: 10.1093/jnci/djv303

Although clinical studies have shown promise for targeting PD1/PDL1 signaling in non-small cell lung cancer (NSCLC), the regulation of PDL1 expression is poorly understood. Here, we show that PDL1 is regulated by p53 via miR-34. p53 wild-type and p53-deficient cell lines (p53(-/-) and p53(+/+) HCT116, p53-inducible H1299, and p53-knockdown H460) were used to determine if p53 regulates PDL1 via miR-34. PDL1 and miR-34a expression were analyzed in samples from patients with NSCLC and mutated p53 vs wild-type p53 tumors from The Cancer Genome Atlas for Lung Adenocarcinoma (TCGA LUAD). We confirmed that PDL1 is a direct target of miR-34 with western blotting and luciferase assays and used a p53(R172HΔ)g/+K-ras(LA1/+) syngeneic mouse model (n = 12) to deliver miR-34a-loaded liposomes (MRX34) plus radiotherapy (XRT) and assessed PDL1 expression and tumor-infiltrating lymphocytes (TILs). A two-sided t test was applied to compare the mean between different treatments. We found that p53 regulates PDL1 via miR-34, which directly binds to the PDL1 3' untranslated region in models of NSCLC (fold-change luciferase activity to control group, mean for miR-34a = 0.50, SD = 0.2, P < .001; mean for miR-34b = 0.52, SD = 0.2, P = .006; and mean for miR-34c = 0.59, SD = 0.14, and P = .006). Therapeutic delivery of MRX34, currently the subject of a phase I clinical trial, promoted TILs (mean of CD8 expression percentage of control group = 22.5%, SD = 1.9%; mean of CD8 expression percentage of MRX34 = 30.1%, SD = 3.7%, P = .016, n = 4) and reduced CD8(+)PD1(+) cells in vivo (mean of CD8/PD1 expression percentage of control group = 40.2%, SD = 6.2%; mean of CD8/PD1 expression percentage of MRX34 = 20.3%, SD = 5.1%, P = .001, n = 4). Further, MRX34 plus XRT increased CD8(+) cell numbers more than either therapy alone (mean of CD8 expression percentage of MRX34 plus XRT to control group = 44.2%, SD = 8.7%, P = .004, n = 4). Finally, miR-34a delivery reduced the numbers of radiation-induced macrophages (mean of F4-80 expression percentage of control group = 52.4%, SD = 1.7%; mean of F4-80 expression percentage of MRX34 = 40.1%, SD = 3.5%, P = .008, n = 4) and T-regulatory cells. We identified a novel mechanism by which tumor immune evasion is regulated by p53/miR-34/PDL1 axis. Our results suggest that delivery of miRNAs with standard therapies, such as XRT, may represent a novel therapeutic approach for lung cancer.