IL-12 can target human lung adenocarcinoma cells and normal bronchial epithelial cells surrounding tumor lesions.
BACKGROUND
Non small cell lung cancer (NSCLC) is a leading cause of cancer death. We have shown previously that IL-12rb2 KO mice develop spontaneously lung adenocarcinomas or bronchioalveolar carcinomas. Aim of the study was to investigate i) IL-12Rbeta2 expression in human primary lung adenocarcinomas and in their counterparts, i.e. normal bronchial epithelial cells (NBEC), ii) the direct anti-tumor activity of IL-12 on lung adenocarcinoma cells in vitro and vivo, and the mechanisms involved, and iii) IL-12 activity on NBEC.


RESULTS
Stage I lung adenocarcinomas showed significantly (P = 0.012) higher frequency of IL-12Rbeta2 expressing samples than stage II/III tumors. IL-12 treatment of IL-12R(+) neoplastic cells isolated from primary adenocarcinoma (n = 6) inhibited angiogenesis in vitro through down-regulation of different pro-angiogenic genes (e.g. IL-6, VEGF-C, VEGF-D, and laminin-5), as assessed by chorioallantoic membrane (CAM) assay and PCR array. In order to perform in vivo studies, the Calu6 NSCLC cell line was transfected with the IL-12RB2 containing plasmid (Calu6/beta2). Similar to that observed in primary tumors, IL-12 treatment of Calu6/beta2(+) cells inhibited angiogenesis in vitro. Tumors formed by Calu6/beta2 cells in SCID/NOD mice, inoculated subcutaneously or orthotopically, were significantly smaller following IL-12 vs PBS treatment due to inhibition of angiogenesis, and of IL-6 and VEGF-C production. Explanted tumors were studied by histology, immuno-histochemistry and PCR array. NBEC cells were isolated and cultured from lung specimens of non neoplastic origin. NBEC expressed IL-12R and released constitutively tumor promoting cytokines (e.g. IL-6 and CCL2). Treatment of NBEC with IL-12 down-regulated production of these cytokines.


CONCLUSIONS
This study demonstrates that IL-12 inhibits directly the growth of human lung adenocarcinoma and targets the adjacent NBEC. These novel anti-tumor activities of IL-12 add to the well known immune-modulatory properties of the cytokine and may provide a rational basis for the development of a clinical trial.
Airoldi
Irma
I
AIRC Tumor Immunology Unit, Department of Experimental and Laboratory Medicine, G Gaslini Institute, Genova, Italy. irmaairoldi@ospedale-gaslini.ge.it
Di Carlo
Emma
E
Cocco
Claudia
C
Caci
Emanuela
E
Cilli
Michele
M
Sorrentino
Carlo
C
Sozzi
Gabriella
G
Ferrini
Silvano
S
Rosini
Sandra
S
Bertolini
Giulia
G
Truini
Mauro
M
Grossi
Francesco
F
Galietta
Luis Juan Vicente
LJ
Ribatti
Domenico
D
Pistoia
Vito
V
D000230:Adenocarcinoma / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001980:Bronchi / Q000473:pathology*; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018664:Interleukin-12 / Q000494:pharmacology* / Q000627:therapeutic use; D008175:Lung Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000235:genetics
D018664:Interleukin-12