Abstract
In the present study, we investigated the mechanisms by which zinc causes growth arrest in colon cancer cells. The results suggest that zinc treatment stabilizes the levels of the wild-type adenomatous polyposis coli (APC) protein at the post-translational level since the APC mRNA levels and the promoter activity of the APC gene were decreased in HCT-116 cells (which express the wild-type APC gene) after treatment with ZnCl2. Increased levels of wild-type but not truncated APC proteins were required for the ZnCl 2-mediated G2/M phase arrest in different colon cancer cell lines. We further tested whether serum-stimulation, which induces cell cycle arrest in the S phase, can relieve ZnCl2-induced G 2/M phase arrest of HCT-116 cells. Results showed that in the HCT-116 cells pretreated with ZnCl2, the serum-stimulation neither changed the distribution of G2/M phase arrested cells nor the increased levels of APC protein. The G2/M phase arrest correlated with retarded growth of HCT-116 cells. To further establish that wild-type APC protein plays a role in ZnCl2-induced G2/M arrest, we treated SW480 colon cancer cells that express truncated APC protein. We found that ZnCl 2 treatment did not induce G2/M phase arrest in SW480 cells; however, the cell growth was retarded due to the loss of E-cadherin and α-tubulin levels. These results suggest that ZnCl2 inhibits the proliferation of colon cancer cells (which carry the wild-type APC gene) through stabilization of the APC protein and cell cycle arrest in the G 2/M phase. On the other hand, ZnCl2 inhibits the proliferation of colon cancer cells (which carry the mutant APC gene) by disrupting cellular attachment and microtubule stability.
Original language | English (US) |
---|---|
Pages (from-to) | 345-357 |
Number of pages | 13 |
Journal | Journal of Cellular Biochemistry |
Volume | 93 |
Issue number | 2 |
DOIs | |
State | Published - 2004 |
Externally published | Yes |
Keywords
- APC
- Cell cycle
- Cellular attachment
- Colon cancer
- Zinc
ASJC Scopus subject areas
- Molecular Biology
- Biochemistry
- Cell Biology