title: COX-2 expression positively correlates with PD-L1 expression in human melanoma cells.
abstract: The resistance to PD-1/PD-L1 inhibitors for the treatment of melanoma have prompted investigators to implement novel clinical trials which combine immunotherapy with different treatment modalities. Moreover is also important to investigate the mechanisms which regulate the dynamic expression of PD-L1 on tumor cells and PD-1 on T cells in order to identify predictive biomarkers of response. COX-2 is currently investigated as a major player of tumor progression in several type of malignancies including melanoma. In the present study we investigated the potential relationship between COX-2 and PD-L1 expression in melanoma.
  
  
  
  Tumor samples obtained from primary melanoma lesions and not matched lymph node metastases were analyzed for both PD-L1 and COX-2 expression by IHC analysis. Status of BRAF and NRAS mutations was analyzed by sequencing and PCR. Co-localization of PD-L1 and COX-2 expression was analyzed by double fluorescence staining. Lastly the BRAFV600EA375 and NRASQ61RSK-MEL-2 melanoma cell lines were used to evaluate the effect of COX-2 inhibition by celecoxib on expression of PD-L1 in vitro.
  
  
  
  BRAFV600E/V600Kand NRASQ61R/Q61Lwere detected in 57.8 and 8.9% of the metastatic lesions, and in 65.9 and 6.8% of the primary tumors, respectively. PD-L1 and COX-2 expression were heterogeneously expressed in both primary melanoma lesions and not matched lymph node metastases. A significantly lower number of PD-L1 negative lesions was found in primary tumors as compared to not matched metastatic lesions (P = 0.002). COX-2 expression significantly correlated with PD-L1 expression in both primary (P = 0.001) and not matched metastatic (P = 0.048) lesions. Furthermore, in melanoma tumors, cancer cells expressing a higher levels of COX-2 also co-expressed a higher level of PD-L1. Lastly, inhibition of COX-2 activity by celecoxib down-regulated the expression of PD-L1 in both BRAFV600EA375 and NRASQ61RSK-MEL-2 melanoma cell lines.
  
  
  
  COX-2 expression correlates with and modulates PD-L1 expression in melanoma cells. These findings have clinical relevance since they provide a rationale to implement novel clinical trials to test COX-2 inhibition as a potential treatment to prevent melanoma progression and immune evasion as well as to enhance the anti-tumor activity of PD-1/PD-L1 based immunotherapy for the treatment of melanoma patients with or without BRAF/NRAS mutations.
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Botti
authors.affiliation: Struttura Complessa di Oncologia Medica e Terapie Innovative, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Fratangelo
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Cerrone
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Liguori
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Cantile
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Anniciello
authors.affiliation: Genomica Funzionale, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Scala
authors.affiliation: Genomica Funzionale, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Crescenzo
authors.initials: C
authors.lastname: D'Alterio
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Trimarco
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", 80131, Naples, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Ianaro
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", 80131, Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cirino
authors.affiliation: Melanoma and Sarcoma Surgery Unit, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Corrado
authors.initials: C
authors.lastname: Caracò
authors.affiliation: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council, 07100, Sassari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Colombino
authors.affiliation: Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council, 07100, Sassari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palmieri
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Baronissi, 84081, Salerno, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pepe
authors.affiliation: Struttura Complessa di Oncologia Medica e Terapie Innovative, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy.
authors.forename: Paolo Antonio
authors.initials: PA
authors.lastname: Ascierto
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Baronissi, 84081, Salerno, Italy. sabbatinof@gmail.com.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sabbatino
authors.affiliation: Dipartimento di Patologia Diagnostica e di Laboratorio: SC di Anatomia Patologica e Citopatologia, Istituto Nazionale Tumori IRCCS Fondazione "G. Pascale", Via Mariano Semmola, 80131, Naples, Italy. giosue.scognamiglio@istitutotumori.it.
authors.forename: Giosuè
authors.initials: G
authors.lastname: Scognamiglio
mesh_terms: D060890:B7-H1 Antigen / Q000378:metabolism*; D000068579:Celecoxib / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D020558:GTP Phosphohydrolases / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000473:pathology; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics; D009154:Mutation / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics
chemical_list: D060890:B7-H1 Antigen; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D048493:Proto-Oncogene Proteins B-raf; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human; D000068579:Celecoxib
keywords: COX-2; Celecoxib; Immune checkpoint molecules; Immunotherapy; Melanoma; PD-L1