Immunological response to renal cryoablation in an in vivo orthotopic renal cell carcinoma murine model.
OBJECTIVE
The immunological consequences of cryoablation for renal cell carcinoma are largely unknown. Cryoablation is an attractive therapeutic option for tumors due to its minimally invasive nature. Cryoablation is also potentially immunogenic. We describe the development of an animal model to deliver in vivo renal cryotherapy to orthotopically implanted renal cell carcinoma and the results of multiple immunological interrogations after cryoablation.


METHODS
Four to 6-week-old female Balb/c mice (Jackson Laboratories, Bar Harbor, Maine) underwent renal subcapsular implantation of the syngeneic murine renal cell carcinoma Renca. Two weeks later contact cryoablation was done in tumor bearing kidneys. Another group of animals underwent cryoablation of normal kidneys. Animals were sacrificed 2 weeks after tumor injection or 1 and 2 weeks after cryoablation, respectively. Kidneys, spleens and draining lymph nodes were harvested. Evaluation consisted of immunohistochemistry, immunofluorescence and gene expression profiling using reverse-transcriptase polymerase chain reaction.


RESULTS
Subcapsular tumor implantation was successful in all cases and confirmed histologically. No significant lymphocytic infiltrate was seen in tumor only animals but those treated with cryoablation (tumor and nontumor bearing) had a significant inflammatory response primarily in sublethal tissue injury and perivascular areas. After cryoablation most infiltrating cells were neutrophils, macrophages and T cells. Polymerase chain reaction showed increased interferon-gamma production in kidneys after cryoablation.


CONCLUSIONS
This study shows the potential feasibility of this animal model for studying cryo-immunology. We confirm the absence of any significant immune cell infiltration in tumor bearing kidneys and report a significant inflammatory infiltrate after cryoablation, consisting primarily of neutrophils, macrophages, and CD4+ and CD8+ T cells with an increase in the T helper type 1/2 ratio. This orthotopic murine model can form the basis of future studies of additional immunological aspects of renal cryoablation.
Matin
Surena F
SF
Department of Urology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
Sharma
Padmanee
P
Gill
Inderbir S
IS
Tannenbaum
Charles
C
Hobart
Michael G
MG
Novick
Andrew C
AC
Finke
James H
JH
D000818:Animals; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000601:surgery*; D003452:Cryosurgery; D004195:Disease Models, Animal; D005240:Feasibility Studies; D005260:Female; D007680:Kidney Neoplasms / Q000276:immunology* / Q000601:surgery*; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D009392:Nephrectomy / Q000379:methods*