title: Irradiation of breast cancer cells enhances CXCL16 ligand expression and induces the migration of natural killer cells expressing the CXCR6 receptor.
abstract: Few studies have examined the migration pattern of natural killer (NK) cells, especially after radiation treatment for cancer. We investigated whether irradiation can modulate the expression of chemokines in cancer cells and the migration of NK cells to irradiated tumor cells.
  
  
  
  The expression of chemokine receptors (CXCR3, CXCR4 and CXCR6) on interleukin-2 (IL-2)/IL-15-activated NK cells was assessed using flow cytometry. Related chemokine ligands (CXCL11, CXCL12 and CXCL16) in human breast cancer cell lines (MCF7, SKBR3 and MDA-MB231) irradiated at various doses were assessed using reverse transcription-polymerase chain reaction (RT-PCR), fluorescence-activated cell sorting (FACS) and enzyme-linked immunosorbent assay (ELISA). The cell-free culture supernatant was collected 96 h after irradiation of breast cancer cell lines for migration and blocking assays.
  
  
  
  The activated NK cells expressed CXCR6. Expression of the CXCR6 ligand CXCL16 increased in a time- and dose-dependent manner in all analyzed cancer cell lines. CXCL16 expression was statistically significantly enhanced in all breast cancer cell lines on day 3 after 20 Gy irradiation. Activated NK cells migration correlated with CXCL16 concentration (R2= 0.91; P <0.0001). Significantly enhanced migration of NK cells to irradiated cancer cells was observed for a dose of 20 Gy in MCF7 (P = 0.043) and SKBR3 (P = 0.043) cells, but not in MDA-MB231 (P = 0.225) cells. A blocking assay using a CXCR6 antibody showed a significant decrease in the migration of activated NK cells in all cancer cell lines.
  
  
  
  Our data indicate that irradiation induces CXCL16 chemokine expression in cancer cells and enhances the migration of activated NK cells expressing CXCR6 to irradiated breast cancer cells. These results suggest that radiation would improve the anti-tumor effect of NK cells through enhanced migration of NK cells to tumor site for the treatment of patients with breast cancer.
authors.affiliation: Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Gwangju, South Korea. Electronic address: meesunyoon@jnu.ac.kr.
authors.forename: Mee Sun
authors.initials: MS
authors.lastname: Yoon
authors.affiliation: Research Center for Cancer Immunotherapy, Chonnam National University Hwasun Hospital, Jeollanam-do, South Korea; Center for Creative Biomedical Scientists at Chonnam National University, Gwangju, South Korea.
authors.forename: Chanh Tin
authors.initials: CT
authors.lastname: Pham
authors.affiliation: Research Center for Cancer Immunotherapy, Chonnam National University Hwasun Hospital, Jeollanam-do, South Korea; Center for Creative Biomedical Scientists at Chonnam National University, Gwangju, South Korea.
authors.forename: Minh-Trang Thi
authors.initials: MT
authors.lastname: Phan
authors.affiliation: Research Center for Cancer Immunotherapy, Chonnam National University Hwasun Hospital, Jeollanam-do, South Korea; Department of Companion & Laboratory Animal Science, Kongju National University, Yesan, South Korea.
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Shin
authors.affiliation: Research Center for Cancer Immunotherapy, Chonnam National University Hwasun Hospital, Jeollanam-do, South Korea.
authors.forename: Youn-Young
authors.initials: YY
authors.lastname: Jang
authors.affiliation: Department of Surgery, Chonnam National University Medical School, Gwangju, South Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Park
authors.affiliation: Department of Companion & Laboratory Animal Science, Kongju National University, Yesan, South Korea.
authors.forename: Sang-Ki
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.
authors.forename: Seokho
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; Stem Cell and Regenerative Medicine Institute, Samsung Medical Center, Seoul, South Korea. Electronic address: duck.cho@skku.edu.
authors.forename: Duck
authors.initials: D
authors.lastname: Cho
mesh_terms: D019138:Antibodies, Blocking / Q000494:pharmacology; D001943:Breast Neoplasms / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000528:radiation effects*; D054377:Chemokine CXCL12 / Q000096:biosynthesis; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC / Q000096:biosynthesis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D019409:Interleukin-15 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D061986:MCF-7 Cells; D054367:Receptors, CXCR3 / Q000096:biosynthesis; D019718:Receptors, CXCR4 / Q000096:biosynthesis; D000075744:Receptors, CXCR6; D019707:Receptors, Chemokine / Q000096:biosynthesis* / Q000276:immunology; D051116:Receptors, Scavenger / Q000096:biosynthesis*; D011991:Receptors, Virus / Q000096:biosynthesis* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology
chemical_list: D019138:Antibodies, Blocking; C515255:CXCL12 protein, human; C423727:CXCL16 protein, human; C515187:CXCR3 protein, human; C527276:CXCR4 protein, human; C106330:CXCR6 protein, human; D054377:Chemokine CXCL12; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC; D019409:Interleukin-15; D007376:Interleukin-2; D054367:Receptors, CXCR3; D019718:Receptors, CXCR4; D000075744:Receptors, CXCR6; D019707:Receptors, Chemokine; D051116:Receptors, Scavenger; D011991:Receptors, Virus
keywords: CXCL16; NK cells; immunotherapy; ionizing radiation; migration