[Efficacy of cryoablation combined with CpG oligonucleotides in the treatment of murine transplanted colon carcinoma].
OBJECTIVE
To investigate the efficacy of cryoablation combined with CpG ODN in the treatment of murine transplanted colon carcinoma.


METHODS
Colon carcinoma model was established by subcutaneously inoculating CT26 cells into the right flank in BALB/c mice. The tumor-bearing mice were randomly divided into 4 groups:the group of PBS injected in peritumoral area, the group of cryoablation, the group of cryoablation combined with CpG ODN, the group of CpG ODN injected in peritumoral area. The tumor size changes were measured. Serum levels of interleukin (IL)-12 and interferon-gamma(IFN-gamma) were assayed by ELISA. The rates of CD3(+)CD4(+)T, CD3(+)CD8(+)T lymphocytes in serum were counted with flow cytometry. Mice in the cryoablation group and the combined group with tumor regression were re-challenged with CT26 cells.


RESULTS
The survival time of cryoablation group and combined therapy group were (80.3 + or - 5.4) days and (83.8 + or - 5.5) days, respectively, longer than (53.7 + or - 3.7) days in PBS group and (51.5 + or - 6.8) days in CpG ODN group(all P<0.05). The suppress rates of tumor cells in cryoablation group and combined therapy group were 83.8% and 86.2% respectively. After 20 days following treatment, CD3(+)CD4(+)T/CD3(+)CD8(+)T ratio and the concentrations of IL-12 and IFN-gamma in mice serum of cryoablation group and combined therapy group were higher than those in PBS group and CpG ODN group(all P<0.05). No significant difference was found in CD3(+)CD4(+)T/CD3(+)CD8(+)T ratio between cryoablation group and combined therapy group(P>0.05). However, the concentrations of IL-12 and IFN-gamma in combined therapy group were higher than those of cryoablation group(all P<0.05). After re-challenging, tumor formation rate in the cryoablation combined with CpG ODN group was 16.7%, significantly lower than that in the cryoablation group(83.8%)(P<0.05).


CONCLUSIONS
Cryoablation combined with CpG ODN can increase antitumor immune response in mice, and therefore can decrease the tumor formation when re-challenged with CT26 cells.
Zou
Ning
N
Oncology Center, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
Lai
Qing-hua
QH
Ding
Wei-min
WM
Li
Xu-feng
XF
Zhang
Ji-ren
JR
D000818:Animals; D003110:Colonic Neoplasms / Q000628:therapy*; D003452:Cryosurgery; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D009838:Oligodeoxyribonucleotides / Q000627:therapeutic use*
C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides