Gene therapy with tumor vaccine increases the survival of hepatoma-bearing mice.
BACKGROUND
Tumor vaccines combined with cytokine gene therapy and Bacillus Calmette-Guérin (BCG) were tested for prevention and therapeutic effects in the H6 mouse hepatoma model.


METHODS
Plasmid DNA of expression vectors carrying cDNA of mouse interleukin (IL)-2 and mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) were used for transfection to obtain H6 mouse hepatoma cells that secreted IL-2 (H6/IL-2) or GM-CSF (H6/GM-CSF). For tumor prevention, groups of mice were immunized twice with irradiated tumor cells with untransduced H6, H6/IL-2, H6/GM-CSF, or an equal mixture of H6/IL-2 and H6/GM-CSF. Three weeks later, these mice were inoculated subcutaneously with live H6 hepatoma cells, and tumor growth was measured. For therapeutic studies, mice first inoculated with live H6 cells were treated three days later with various irradiated tumor cell vaccines alone or in combination with BCG. Subsequent tumor growth was measured.


RESULTS
In tumor prevention studies, significant protection from tumor growth has been observed in animals vaccinated with irradiated cytokine-secreting H6 cells compared with those immunized with irradiated parental H6 cells. In tumor therapy studies, subsequent administration of irradiated H6/GM-CSF cells in combination with BCG impeded the tumorigenicity of preinoculated live H6 hepatoma cells.


CONCLUSIONS
These results suggest that cytokine-secreting tumor vaccines have a prophylactic effect and BCG, in combination with irradiated H6/GM-CSF cells, shows a synergistic effect on delaying the growth of H6 mouse hepatomas.
Chao
Y
Y
Cancer Center, Taipei Veterans General Hospital, Taiwan, ROC.
Shih
Y L
YL
Cheng
H J
HJ
Wei
S J
SJ
Chi
K H
KH
Yeh
S H
SH
Lee
S D
SD
Yang
W K
WK
D000818:Animals; D001500:BCG Vaccine / Q000627:therapeutic use; D019496:Cancer Vaccines / Q000627:therapeutic use*; D005260:Female; D015316:Genetic Therapy; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics*; D007376:Interleukin-2 / Q000235:genetics*; D008114:Liver Neoplasms, Experimental / Q000401:mortality / Q000628:therapy*; D051379:Mice
D001500:BCG Vaccine; D019496:Cancer Vaccines; D007376:Interleukin-2; D016178:Granulocyte-Macrophage Colony-Stimulating Factor