Immunotherapy of neuroblastoma by an Interleukin-21-secreting cell vaccine involves survivin as antigen.
OBJECTIVE
IL-21 is the most recently identified member of the IL-2 cytokine family. Here we studied the therapeutic efficacy of IL-21-gene-modified cells (Neuro2a/IL-21) in a syngeneic metastatic neuroblastoma (NB) model.


METHODS
Neuro2a/IL-21 cells were tested as subcutaneous (sc) vaccine both in prophylactic and therapeutic settings. Depletion studies, cytotoxicity assay and immunohistochemical analyses were carried out to evaluate the mechanisms involved in tumor rejection.


RESULTS
When injected sc in syngeneic A/J mice viable Neuro2a/IL-21 cells were rejected and induced resistance to a subsequent iv challenge with Neuro2a parental cells (Neuro2a/pc), suggesting the involvement of an immune response. More importantly, in mice bearing Neuro2a/pc micrometastases, a single sc injection of Neuro2a/IL-21 cells significantly increased the mean tumor-free survival of treated animals (43 vs. 22 days) and cured 14% of them. The administration of two or three doses of Neuro2a/IL-21 cell vaccine further increased the mean survival time to 54 and 75 days, and the cure rate to 27 and 33%, respectively, whereas the use of unmodified Neuro2a or mock-transfected cells had no effect. In vivo cell subset depletion and a Winn-assay indicated the involvement of CD8 + CTLs. Immunohistochemical analysis indicated a reduction of CD31+ and VEGFR2+ microvessels in late metastases from therapeutically vaccinated mice. A role of survivin as antigen was suggested by in vitro assays using survivin-synthetic CTL-epitopes.


CONCLUSIONS
Our present data indicate that IL-21-secreting NB cells are effective as therapeutic vaccine in mice bearing metastatic NB, through a specific CTL response involving survivin as antigen, and suggest a potential interest for IL-21 in NB immuno-gene therapy.
Croce
Michela
M
Laboratory of Immunological Therapy, Istituto Nazionale per la Ricerca sul Cancro, Largo Benzi 10, 16132 Genoa, Italy.
Meazza
Raffaella
R
Orengo
Anna M
AM
Fabbi
Marina
M
Borghi
Martina
M
Ribatti
Domenico
D
Nico
Beatrice
B
Carlini
Barbara
B
Pistoia
Vito
V
Corrias
Maria Valeria
MV
Ferrini
Silvano
S
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D019496:Cancer Vaccines / Q000627:therapeutic use*; D005260:Female; D015316:Genetic Therapy; D006801:Humans; D007167:Immunotherapy; D051034:Inhibitor of Apoptosis Proteins; D007371:Interferon-gamma / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism*; D051379:Mice; D008805:Mice, Inbred A; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008869:Microtubule-Associated Proteins / Q000276:immunology / Q000378:metabolism*; D009447:Neuroblastoma / Q000276:immunology / Q000628:therapy*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D000077022:Survivin; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D014611:Vaccination; D000098546:Interleukin-21
C117749:Birc5 protein, mouse; D019496:Cancer Vaccines; D051034:Inhibitor of Apoptosis Proteins; D007378:Interleukins; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D000077022:Survivin; D007371:Interferon-gamma; D014446:Tyrosine 3-Monooxygenase; D000098546:Interleukin-21