Captopril, an angiotensin-converting enzyme inhibitor, promotes growth of immunogenic tumors in mice.
OBJECTIVE
Antitumor potential of angiotensin-converting enzyme inhibitors has been shown in different preclinical settings, which always involved immunocompromised organisms or nonimmunogenic tumor models. In our study, we wanted to evaluate the effect of captopril on growth of immunogenic tumors in immunocompetent animals.


METHODS
We used different murine tumor models to evaluate the effect of captopril on tumor take and survival of tumor-bearing immunocompetent and immunocompromised mice. We used an orthotopic renal cell cancer model and highly immunogenic tumor model, which were based on kidney subcapsular injection of RenCa cells or s.c. injection of MethA cells, respectively. To show the influence of captopril on antigen-specific immune responses, we have used two model antigens (green fluorescent protein and beta-galactosidase).


RESULTS
Captopril decreased survival of RenCa-bearing, immunocompetent mice in a dose-dependent manner and in adjuvant setting. In nephrectomized mice, captopril shortened their survival. Captopril promoted formation of immunogenic MethA sarcoma tumors but had no effect on nonimmunogenic melanoma cells (B78-H1). Treatment of immunocompromised mice bearing MethA tumors or RenCa kidney tumors with captopril did not affect tumor formation nor survival, respectively. Captopril-treated mice immunized with AdLacZ or AdGFP vectors did not generate or generated decreased numbers of antigen-specific CD8+ T cells, respectively. However, they showed B-cell responses represented by infiltration of MethA tumors with activated B cells and dramatically increased serum level of beta-galactosidase-specific antibodies.


CONCLUSIONS
Our results show a novel role of captopril in tumor biology and the tumor-promoting properties of captopril seem to be associated with its immunomodulatory potential.
Wysocki
Piotr J
PJ
Department of Cancer Immunology, University of Medical Sciences at GreatPoland Cancer Center, Poznan, Poland. pwysocki@plusnet.pl
Kwiatkowska
Eliza P
EP
Kazimierczak
Urszula
U
Suchorska
Wiktoria
W
Kowalczyk
Dariusz W
DW
Mackiewicz
Andrzej
A
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002216:Captopril / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D012513:Sarcoma, Experimental / Q000276:immunology / Q000473:pathology*; D014183:Transplantation, Heterologous; D023041:Xenograft Model Antitumor Assays
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril