[Interleukin-12 gene transfection into murine B16 melanoma cells suppresses tumorigenicity and decreases metastatic potential].
OBJECTIVE
To study the tumorigenicity and metastasis of poorly immunogenic murine B16 melanoma cells transfected with murine interleukin-12 (IL-12) gene.


METHODS
Two recombinant vectors containing the full length cDNA of p40 or p35 subunit of IL-12 were constructed. They were cotransfected into B16 melanoma cells by LipofectAMIN method. The expressions of p40 and p35 mRNAs were analyzed by means of reverse transcription polymerase chain reaction (RT-PCR). The secretion of bioactive IL-12 was detected by bioassay (measuring the proliferative response of PMA-activated murine splenocytes). To determine the effects of IL-12 secreted by genetically engineered B16 cells (B16T-IL12) on tumorigenesis and metastasis, the cells were inoculated s.c. or i.v. into C57BL/6 mice.


RESULTS
B16T-IL12 cells expressed both p40 and p35 mRNAs, also produced bioactive IL-12. Only 70% of the mice injected with B16T-IL12 cells developed palpable tumors. The emergence of palpable tumors in the mice inoculated with B16T-IL12 cells was significantly delayed (P < 0.01), the growth rate of the tumors was obviously decreased (P < 0.01), and the survival time of tumor-bearing mice was prolonged substantially (P < 0.01), compared with the control B16 or B16Tneo cells. The incidence of experimental pulmonary metastasis of B16T-IL12 cells was inhibited, and the number of pulmonary metastases was reduced markedly, in contrast to the i.v. inoculation of B16 cells (P < 0.01).


CONCLUSIONS
Transfection of IL-12 gene into B16 cells results in the inhibition of tumorigenesis and in the suppression of experimental pulmonary metastasis.
Fu
J
J
Department of Pathology, Beijing Medical University.
Zheng
J
J
Fang
W
W
D000818:Animals; D005260:Female; D018014:Gene Transfer Techniques; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics*; D008175:Lung Neoplasms / Q000517:prevention & control / Q000556:secondary; D008297:Male; D008546:Melanoma, Experimental / Q000235:genetics* / Q000517:prevention & control; D051379:Mice; D008810:Mice, Inbred C57BL; D014162:Transfection
D018664:Interleukin-12