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Suppression of pancreatic cancer by the dominant negative ras mutant, N116Y
T Shichinohe1, N Senmaru, K Furuuchi
1Laboratory of Gene Regulation, Cancer Institute, Hokkaido University School of Medicine, Sapporo, Japan.
Abstract:
N116Y, H-ras mutant, possesses dominant negative activity to Ras function. The aim of this study is to assess whether N116Y can inhibit the proliferation of pancreatic cancer cell lines carrying K-ras mutations and cause reversion of the malignant phenotype. We transfected an expression vector of N116Y, pZIP-N116Y, into eight human pancreatic cancer cell lines with K-ras mutations (PCI 10, 19, 24, 35, 43, 55, 64, and 66) by using a lipofection procedure. The growth inhibition activity of N116Y was evaluated by the colony-forming efficiency in selection medium. In order to examine the effect of N116Y on the neoplastic phenotype, we established N116Y-expressing clones and analyzed their growth ability in soft agar and tumorigenicity in nude mice. The growth of the eight pancreatic cancer cell lines was strongly inhibited by the transfection of pZIP-N116Y. Moreover, the N116Y-expressing clones became less spread and lost their anchorage-independent growth ability. Furthermore, they were nontumorigenic in vivo. N116Y significantly inhibits the growth of pancreatic cancer cell lines and causes reversion of the malignant phenotypes. These results suggest that N116Y may be a candidate gene for use in the gene therapy of pancreatic cancer.
Insights
The N116Y mutant Ras protein inhibits pancreatic cancer cell growth and reverses malignant phenotypes. This suggests N116Y holds potential for pancreatic cancer gene therapy.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Genetics
Background:
- Ras proteins are critical regulators of cell signaling.
- Mutations in Ras genes, particularly K-ras, are common drivers in pancreatic ductal adenocarcinoma.
- Dominant-negative Ras mutants offer a potential therapeutic strategy.
Purpose of the Study:
- To investigate the efficacy of N116Y, a dominant-negative H-ras mutant, in inhibiting pancreatic cancer cell proliferation.
- To determine if N116Y can reverse the malignant phenotype of pancreatic cancer cell lines with K-ras mutations.
Main Methods:
- Transfection of the N116Y expression vector (pZIP-N116Y) into eight human pancreatic cancer cell lines harboring K-ras mutations.
- Assessment of growth inhibition using colony-forming efficiency assays.
- Analysis of phenotypic reversion by evaluating soft agar colony formation and in vivo tumorigenicity in nude mice.
Main Results:
- Transfection with pZIP-N116Y significantly inhibited the growth of all eight K-ras-mutated pancreatic cancer cell lines.
- N116Y-expressing clones exhibited reduced cellular spreading and lost anchorage-independent growth.
- N116Y-expressing clones were non-tumorigenic in nude mouse models.
Conclusions:
- N116Y demonstrates potent inhibition of pancreatic cancer cell growth.
- N116Y effectively reverses key malignant phenotypes associated with pancreatic cancer.
- N116Y represents a promising candidate gene for pancreatic cancer gene therapy.