Up-regulation of tumor interleukin-8 expression by infiltrating macrophages: its correlation with tumor angiogenesis and patient survival in non-small cell lung cancer.
OBJECTIVE
To evaluate the interaction between tumor-infiltrating macrophages and cancer cells and its effect on the expression of a potent angiogenic factor, interleukin-8 (IL-8), tumor angiogenesis, and patient outcome in non-small cell lung cancer (NSCLC).


METHODS
We measured tumor IL-8 mRNA expression (by real-time quantitative reverse transcription-PCR), intratumor microvessel counts, and tumor-infiltrating macrophage density (by immunohistochemical staining) in 35 NSCLC surgical specimens and correlated with the patient's clinical outcome. We then investigated the interaction between macrophages (cell line THP-1) and six different human cancer cell lines (four NSCLCs, one osteosarcoma, and one hepatoma) and its effect on IL-8 mRNA expression using a macrophage/cancer cell coculture system, IL-8 mRNA expression in lung cancer cells, and macrophages being measured separately after coculture in the presence or absence of six anti-inflammatory agents, i.e., pentoxifylline, aspirin, indomethacin, dexamethasone, celecoxib (a selective cyclooxygenase-2 inhibitor), and pyrrolidine dithiocarbamate, a specific nuclear factor kappaB (NF-kappaB) inhibitor. NF-kappaB transcriptional activity and protein levels were measured by reporter gene assay and Western blot.


RESULTS
The tumor-infiltrating macrophage density correlated significantly and positively with tumor IL-8 mRNA expression and intratumor microvessel counts and significantly and negatively with patient survival. In addition, after cell-cell interaction in cancer cell:macrophage cocultures, marked IL-8 mRNA expression was induced in lung cancer cells (approximately 270-fold) and, to a lesser degree, in macrophages (4.5-fold). The increase in IL-8 mRNA expression correlated with the in vitro metastatic potential of the cancer cells. All six anti-inflammatory agents suppressed induction of IL-8 mRNA expression in lung cancer cells by >90%, four (pentoxifylline, celecoxib, pyrrolidine dithiocarbamate, and dexamethasone) having a dose-dependent effect. NF-kappaB transcriptional regulation and protein levels were simultaneously increased in the nuclei of cancer cells in macrophage/cancer cell cocultures, this effect also being suppressed by all six anti-inflammatory agents.


CONCLUSIONS
The interaction between infiltrating macrophages and cancer cells up-regulates IL-8 mRNA expression, especially in the cancer cells; this may contribute greatly to the increased tumor angiogenesis and adverse outcome in NSCLC patients with a high density of tumor-infiltrating macrophages. Anti-inflammatory agents can suppress the induction of IL-8 mRNA expression seen in lung cancer cells after coculture with macrophages, and this suppression is mediated, in part, through the NF-kappaB pathway.
Chen
Jeremy J W
JJ
Institute of Biomedical Sciences and Molecular Biology, National Chung Hsing University, Taichung, Taiwan 402, Republic of China.
Yao
Pei-Li
PL
Yuan
Ang
A
Hong
Tse-Ming
TM
Shun
Chia-Tung
CT
Kuo
Min-Liang
ML
Lee
Yung-Chie
YC
Yang
Pan-Chyr
PC
D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000235:genetics / Q000276:immunology* / Q000401:mortality; D002460:Cell Line; D018920:Coculture Techniques; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000235:genetics*; D008175:Lung Neoplasms / Q000098:blood supply / Q000235:genetics / Q000276:immunology* / Q000401:mortality; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D008297:Male; D008833:Microcirculation / Q000276:immunology / Q000473:pathology; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D016209:Interleukin-8; D012333:RNA, Messenger