title: EML4-ALK enhances programmed cell death-ligand 1 expression in pulmonary adenocarcinoma via hypoxia-inducible factor (HIF)-1α and STAT3.
abstract: Programmed cell death (PD)-1/PD-1 ligand-1 (PD-L1)-targeted therapy has emerged as a promising therapeutic strategy for lung cancer. However, whether EML4-ALK regulates PD-L1 expression in lung cancer remains unknown. A total of 532 pulmonary adenocarcinomas (pADCs), including 58ALK-translocated tumors, were immunohistochemically evaluated for PD-L1 and PD-1. H23 (EGFRWild-typeEML4-ALK-PD-L1Low) and H2228 (EGFRWild-typeEML4-ALK+PD-L1High) cells were transfected withEML4-ALKor ALK short interfering RNAs and used to investigate the alterations in PD-L1 expression. PD-L1 expression was detected in 81% ofALK-translocated pADCs; this value was significantly higher than those of pADCs withEGFRmutation,KRASmutation or lackingALK, EGFRorKRASmutation (p<0.005 for all). Moreover,ALK-translocated pADC with PD-L1 expression showed significantly higher numbers of tumor-infiltrating PD-1+cells. ALK knockdown or inhibition (crizotinib treatment) in H2228 cells downregulated PD-L1 expression. Transfection of H23 cells withEML4-ALKenhanced PD-L1 expression, which was compromised by crizotinib treatment. This ALK-dependent upregulation of PD-L1 expression was mediated by STAT3 and hypoxia-inducible factor (HIF)-1α under normoxia and hypoxia. Furthermore, EML4-ALK enhanced HIF-1α expression through increasing transcription and decreasing ubiquitination of HIF-1α. InALK-translocated pADC tissues, significant positive correlations between PD-L1 and nuclear HIF-1α (p< 0.05) or pSTAT3 expression levels (p<0.005) were observed. Among patients withALK-translocated pADC, strong PD-L1 expression was significantly associated with shorter progression-free (p= 0.001) and overall survival (p= 0.002) after crizotinib treatment. Collectively, our findings demonstrate thatALK-derived pADCs increase PD-L1 expression via HIF-1α and/or STAT3, thus providing a rationale for PD-1/PD-L1 pathway-targeted therapy inALK-translocated lung cancer.
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jaemoon
authors.initials: J
authors.lastname: Koh
authors.affiliation: Tumor Immunity Medical Research Center, Cancer Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea; Tumor Microenvironment Global Core Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine , Seoul, Republic of Korea.
authors.forename: Bhumsuk
authors.initials: B
authors.lastname: Keam
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine , Seoul, Republic of Korea.
authors.forename: Sehui
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine , Seoul, Republic of Korea.
authors.forename: Moon-Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine , Seoul, Republic of Korea.
authors.forename: Heounjeong
authors.initials: H
authors.lastname: Go
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine , Seoul, Republic of Korea.
authors.forename: Tae Min
authors.initials: TM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine , Seoul, Republic of Korea.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea; Tumor Immunity Medical Research Center, Cancer Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea; Tumor Microenvironment Global Core Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Chul-Woo
authors.initials: CW
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea; Tumor Immunity Medical Research Center, Cancer Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yoon Kyung
authors.initials: YK
authors.lastname: Jeon
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; Ischemic/Hypoxia Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Doo Hyun
authors.initials: DH
authors.lastname: Chung
keywords: Adenocarcinoma; anaplastic lymphoma kinase; cancer immunotherapy; hypoxia-inducible factor-1; immune checkpoint; programmed cell death-1; programmed cell death-ligand 1