Antisense oligonucleotide specific for transforming growth factor-beta 1 inhibit both in vitro and in vivo growth of MBT-2 murine bladder cancer.
OBJECTIVE
TGF-beta is a potent immunosuppressive cytokine produced by many tumor cells. Secretion of TGF-beta by malignant cells may be a mechanism by which tumor cells escape destruction by tumor-specific T lymphocytes. In this study, we used a TGF-beta producing C3H/He-MBT-2 murine bladder tumor model to investigate the feasibility of antisense oligonucleotide (ODN) gene therapy strategy to block the production of TGF-beta from tumor cells and evaluate its influence on both in vitro tumor growth and in vivo tumor formation.


METHODS
Using a plasmid, pRUFCD, we constructed a recombinant plasmid pRUFCD/TGF-beta 1(-) containing antisense TGF-beta ODN and then transfected in into MBT-2 cells by electroporation. Three transfectant clones were successfully obtained by their resistance to 5-fluorouracil and cytosine.


RESULTS
The secretion of TGF-beta from the three obtained TGF-beta antisense-blocked MBT-2 cell clones, as assessed by ELISA, were all decreased. Moreover, they all exhibited smaller colony size in the in vitro anchorage-independent soft agar colony forming assay. Tumor growths in mice injected with these three clones were all inhibited compared with those injected with parental tumor cells.


CONCLUSIONS
This study demonstrates that after reducing the secretion of TGF-beta 1 on tumor cells by TGF-beta 1 antisense, ODN can inhibit their in vitro growth and in vivo tumor formation suggesting that this approach can be a potentially useful strategy to abolish the adverse immunosuppression effect of TGF-beta 1 producing autologous tumor vaccine and therefore to enhance host antitumor immune response.
Tzai
T S
TS
Department of Urology, National Cheng Kung University, Tainan, Taiwan, Republic of China.
Lin
C I
CI
Shiau
A L
AL
Wu
C L
CL
D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D005260:Female; D015316:Genetic Therapy / Q000379:methods; D051379:Mice; D008809:Mice, Inbred C3H; D016376:Oligonucleotides, Antisense / Q000627:therapeutic use* / Q000633:toxicity*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics*; D001749:Urinary Bladder Neoplasms / Q000473:pathology* / Q000628:therapy*
D016376:Oligonucleotides, Antisense; D016212:Transforming Growth Factor beta