Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis

Lidija Klampfer, Laurie Anne Swaby, Jie Huang, Takehiko Sasazuki, Senji Shirasawa, Leonard Augenlicht

Research output: Contribution to journalArticle

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Abstract

Despite the fact that objective response rates to 5-FU are as low as 20%, 5-FU remains the most commonly used drug for the treatment of colorectal cancer. The lack of understanding of resistance to 5-FU, therefore, remains a significant impediment in maximizing its efficacy. We used intestinal epithelial cells with an inducible K-RasV12 to demonstrate that expression of oncogenic Ras promotes cell death upon 5-FU treatment. Accordingly, transient expression of the mutant RasV12, but not the WT Ras, enhanced 5-FU-induced apoptosis in 293T cells. Consistent with these data, we showed that targeted deletion of the mutant Ras allele in the HCT116 colon cancer cell line protected cells from 5-FU-induced apoptosis. Using isogenic colon cancer cell lines that differ only by the presence of the mutant Ras allele, HCT116 and Hke-3 cells, we demonstrated that signaling by oncogenic Ras promotes both accumulation of p53 and its phosphorylation on serine15 in response to 5-FU, a situation that favors apoptosis over growth arrest. However, despite the differential induction of p53 in HCT116 and Hke-3 cells, the expression of Puma, a gene with an important role in p53-dependent apoptosis, was not affected by Ras signaling. In contrast, we showed that Ras interferes with 5-FU-induced expression of gelsolin, a protein with known antiapoptotic activity. We ascertained the role of gelsolin in 5-FU-induced apoptosis by demonstrating that silencing of gelsolin expression through RNAi sensitized cells to 5-FU-induced apoptosis and that re-expression of gelsolin in cells harboring mutant Ras protected cells from 5-FU-induced apoptosis. These data therefore demonstrate that Ras mutations increase sensitivity to 5-FU-induced apoptosis at least in part through the negative regulation of gelsolin expression. Our data indicate that Ras mutations promote apoptosis in response to 5-FU treatment and imply that tumors with Ras mutations and/or reduced expression of gelsolin may show enhanced apoptosis in response to 5-FU also in vivo.

Original languageEnglish
Pages (from-to)3932-3941
Number of pages10
JournalOncogene
Volume24
Issue number24
DOIs
Publication statusPublished - Jun 2 2005
Externally publishedYes

Fingerprint

Fluorouracil
Colonic Neoplasms
Apoptosis
Gelsolin
Mutation
Puma
Alleles
Cell Line
HEK293 Cells
RNA Interference
Colorectal Neoplasms
Cell Death
Epithelial Cells
Phosphorylation

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Genetics
  • Cancer Research

Cite this

Klampfer, L., Swaby, L. A., Huang, J., Sasazuki, T., Shirasawa, S., & Augenlicht, L. (2005). Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis. Oncogene, 24(24), 3932-3941. https://doi.org/10.1038/sj.onc.1208552

Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis. / Klampfer, Lidija; Swaby, Laurie Anne; Huang, Jie; Sasazuki, Takehiko; Shirasawa, Senji; Augenlicht, Leonard.

In: Oncogene, Vol. 24, No. 24, 02.06.2005, p. 3932-3941.

Research output: Contribution to journalArticle

Klampfer, L, Swaby, LA, Huang, J, Sasazuki, T, Shirasawa, S & Augenlicht, L 2005, 'Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis', Oncogene, vol. 24, no. 24, pp. 3932-3941. https://doi.org/10.1038/sj.onc.1208552
Klampfer L, Swaby LA, Huang J, Sasazuki T, Shirasawa S, Augenlicht L. Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis. Oncogene. 2005 Jun 2;24(24):3932-3941. https://doi.org/10.1038/sj.onc.1208552
Klampfer, Lidija ; Swaby, Laurie Anne ; Huang, Jie ; Sasazuki, Takehiko ; Shirasawa, Senji ; Augenlicht, Leonard. / Oncogenic Ras increases sensitivity of colon cancer cells to 5-FU-induced apoptosis. In: Oncogene. 2005 ; Vol. 24, No. 24. pp. 3932-3941.
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