Related Experiment Videos
Transforming growth factor-beta 1 induces apoptosis in gastric cancer cells through a p53-independent pathway
M Yamamoto1, Y Maehara, Y Sakaguchi
1Cancer Center of Kyushu University Hospital, Fukuoka, Japan.
Background:
Apoptosis is induced by various anticancer agents or radiation through the tumor suppressor gene p53-dependent pathway and is also induced by other factors, including transforming growth factor-beta 1 (TGF-beta 1). In this study, the authors investigated whether TGF-beta 1 would induce apoptosis in gastrointestinal cancer cells, and its relation to the status of the p53 gene.
Methods:
The induction of apoptosis by TGF-beta 1 was determined in 12 gastrointestinal cancer cell lines using DNA ladder formation. Status of the p53 gene was examined by sequencing of cDNA from p53 mRNA and expressions of TGF-beta 1 mRNA and TGF receptors I and II mRNAs were determined by Northern blot analysis and the reverse transcriptase-polymerase chain reaction analysis, respectively.
Results:
Of 12 cell lines, wild-type p53 was present in 3 lines, point mutation was detected in 7 lines, and p53 mRNA was absent in 2 lines. TGF-beta 1 was expressed in all 12 lines, but both TGF receptors I and II were expressed in only 6 lines. Addition of TGF-beta 1 induced DNA ladder formation only in KATOIII cells, with deleted p53 mRNA, but expressed TGF receptors I and II.
Conclusions:
These findings show that TGF-beta 1 induces apoptosis in gastric cancer cells through TGF-beta receptors I and II and a p53-independent pathway.
Insights
Transforming growth factor-beta 1 (TGF-beta 1) induces apoptosis in gastric cancer cells. This process occurs independently of the p53 gene status, highlighting a novel therapeutic target.
Area of Science:
- Gastrointestinal Oncology
- Molecular Biology
- Cancer Research
Background:
- Apoptosis, programmed cell death, is crucial in cancer therapy.
- The tumor suppressor gene p53 pathway is a common target for anticancer agents.
- Transforming growth factor-beta 1 (TGF-beta 1) is another factor known to induce apoptosis.
Purpose of the Study:
- To investigate if TGF-beta 1 induces apoptosis in gastrointestinal cancer cells.
- To determine the relationship between TGF-beta 1-induced apoptosis and the p53 gene status.
Main Methods:
- Assessed apoptosis induction via DNA ladder formation in 12 gastrointestinal cancer cell lines.
- Analyzed p53 gene status through cDNA sequencing of p53 mRNA.
- Quantified TGF-beta 1, TGF receptor I, and TGF receptor II mRNA expression using Northern blot and RT-PCR.
Main Results:
- p53 gene status varied: 3 wild-type, 7 point mutations, 2 absent p53 mRNA.
- TGF-beta 1 was universally expressed, but TGF receptors I and II were present in only 6 cell lines.
- TGF-beta 1 induced apoptosis (DNA ladder formation) exclusively in KATOIII cells, which lacked p53 mRNA but expressed TGF receptors.
Conclusions:
- TGF-beta 1 effectively induces apoptosis in gastric cancer cells.
- The mechanism involves TGF-beta receptors I and II.
- This apoptotic pathway is independent of the p53 gene status.