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Controlled release of TGF-beta1 impedes rat colon carcinogenesis in vivo
R Mikhailowski1, B Shpitz, S Polak-Charcon
1Gastroenterology Department, Soroka Medical Center, Beer Sheva, Israel.
Abstract:
Transforming growth factor beta1 (TGF-beta1) is a cytokine known to play a key role in the control of cell growth. TGF-beta1 potently inhibits the proliferation of human and rodent-derived epithelial cells. Colonic precancerous and moderately differentiated cancer cells are responsive to TGF-beta1, whereas malignant colon cancer cells are resistant to the inhibitory action of the cytokine. These observations have been derived exclusively from in vitro studies. Therefore, the main aim of our study was to determine whether TGF-beta1 exerts a growth-restraining action on colon carcinogenesis in vivo. TGF-beta1 was sequestered into ethylene acetate copolymer matrices and "loaded" preparations were implanted intraperitoneally (i.p.) in rats. One week later, the animals were treated with dimethylhydrazine (DMH), a colon procarcinogen. Empty matrices devoid of TGF-beta1 but containing bovine serum albumin (BSA) carrier served as the appropriate control preparations. The number of aberrant crypt foci (ACF), considered to be preneoplastic lesions of the colon, was scored. Tumor formation and size were assessed at the appropriate times. TGF-beta1 released in a sustained manner from copolymer matrices: (i) markedly inhibited colonic ACF formation and the number of aberrant crypts and (ii) significantly reduced colonic tumor formation and size.
Insights
Transforming growth factor beta1 (TGF-beta1) effectively inhibited colon cancer growth in rats. Sustained release of TGF-beta1 reduced preneoplastic lesions and tumor development, demonstrating its in vivo anti-cancer potential.
Area of Science:
- Oncology
- Cell Biology
- Biochemistry
Background:
- Transforming growth factor beta1 (TGF-beta1) is a cytokine that inhibits epithelial cell proliferation.
- In vitro studies show TGF-beta1 inhibits precancerous and moderately differentiated colon cells, but not malignant ones.
- The in vivo efficacy of TGF-beta1 in colon carcinogenesis remains largely uninvestigated.
Purpose of the Study:
- To investigate the in vivo effect of sustained-release TGF-beta1 on colon carcinogenesis in a rat model.
- To determine if TGF-beta1 can inhibit the formation and growth of preneoplastic lesions and tumors in the colon.
Main Methods:
- Sustained release of TGF-beta1 was achieved using ethylene acetate copolymer matrices implanted intraperitoneally in rats.
- Rats were treated with dimethylhydrazine (DMH), a colon procarcinogen, one week post-implantation.
- Control groups received empty matrices with bovine serum albumin (BSA) carrier.
- Aberrant crypt foci (ACF) and tumor formation/size were assessed.
Main Results:
- Sustained release of TGF-beta1 significantly inhibited the formation of colonic ACF and reduced the number of aberrant crypts.
- TGF-beta1 treatment markedly reduced the incidence and size of colon tumors.
- These findings confirm the in vivo growth-restraining action of TGF-beta1 on colon carcinogenesis.
Conclusions:
- Sustained delivery of TGF-beta1 via copolymer matrices is an effective strategy to suppress colon carcinogenesis in vivo.
- TGF-beta1 demonstrates significant potential as a therapeutic agent for preventing or treating colon cancer.
- Further research into TGF-beta1-based therapies for colon cancer is warranted.