A central role for tumor-derived monocyte chemoattractant protein-1 in malignant pleural effusion.
BACKGROUND
Tumor cells in malignant pleural effusions (MPEs) are an important source of monocyte chemoattractant protein (MCP)-1. However, the role of tumor-derived MCP-1 in the pathogenesis and progression of MPE has not been determined.


METHODS
B16 mouse skin melanoma cells, which are deficient in MCP-1 expression, and mouse Lewis lung cancer (LLC) cells, which express high levels of MCP-1, were engineered to stably express MCP-1 and short hairpin RNAs (shRNAs) targeting the MCP-1 transcript, respectively. Cells were injected into the pleural cavities of syngeneic immunocompetent mice, and MPE volume and pleural tumors were quantified at necropsy (day 14). MCP-1 and other mediators were determined by cytometric bead array and enzyme-linked immunosorbent assay, and mononuclear and endothelial cells were identified by immunolabeling of F4/80 and factor VIII-related antigen respectively. Mouse survival was assessed using Kaplan-Meier analysis. Vascular permeability in mice with MPE was assessed using albumin-binding Evans blue. Statistical tests were two-sided.


RESULTS
LLC cells expressing shRNA against MCP-1 elaborated less than 5% of the MCP-1 level in cells expressing nonspecific shRNA (control cells), and intrapleural delivery of these cells resulted in less MPE (mean MPE volume = 86 and 585 muL, respectively; difference = 499 muL; 95% confidence interval [CI] = 331 to 669 muL; P < .001), reduced MCP-1 levels in the pleural fluid, and lower mortality than when control cells were delivered. Overexpression of MCP-1 in intrapleurally injected B16 melanoma cells led to increased MPE and reduced survival. In mice with MPE, MCP-1 was a potent inducer of vascular permeability, mononuclear recruitment, and, in pleural tumors, of angiogenesis.


CONCLUSIONS
MCP-1 produced by tumor cells is an important determinant of their capacity to induce the formation of MPE and may be a useful target for the treatment of malignant pleural disease.
Applied Biomedical Research and Training Center Marianthi Simou, Department of Critical Care and Pulmonary Services, General Hospital Evangelismos, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece. gstathop@med.uoa.gr
Georgios T
GT
Stathopoulos
Ioannis
I
Psallidas
Ardiana
A
Moustaki
Charalampos
C
Moschos
Androniki
A
Kollintza
Sophia
S
Karabela
Ilias
I
Porfyridis
Spyridoula
S
Vassiliou
Marilena
M
Karatza
Zongmin
Z
Zhou
Myungsoo
M
Joo
Timothy S
TS
Blackwell
Charis
C
Roussos
Daniel
D
Graf
Ioannis
I
Kalomenidis
D000818:Animals; D002199:Capillary Permeability; D018827:Carcinoma, Lewis Lung / Q000098:blood supply / Q000235:genetics / Q000276:immunology / Q000473:pathology; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D008297:Male; D008546:Melanoma, Experimental / Q000098:blood supply / Q000235:genetics / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000098:blood supply / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000276:immunology / Q000473:pathology; D010957:Plasmids / Q000235:genetics; D016066:Pleural Effusion, Malignant / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics; D012878:Skin Neoplasms / Q000098:blood supply / Q000235:genetics / Q000276:immunology / Q000473:pathology; D014162:Transfection
D018932:Chemokine CCL2; D034741:RNA, Small Interfering