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Lovastatin inhibits pancreatic cancer growth regardless of RAS mutation
S Sumi1, R D Beauchamp, C M Townsend
1Department of Surgery, University of Texas Medical Branch, Galveston 77555-0533.
Abstract:
Lovastatin, an inhibitor of the rate-limiting enzyme of cholesterol synthesis, inhibits growth of pancreatic cancer cells. A possible mechanism of this inhibition is that lovastatin inhibits the activity of RAS protein by depleting farnesyl (an intermediate of cholesterol synthesis). The K-ras gene is frequently mutated in pancreatic cancers and RAS protein requires farnesyl to be bound to the cell membrane and thereby activated. To investigate whether lovastatin inhibition of cell growth depends upon the presence of ras mutation, codons 12/13 and 61 of ras genes were examined by the dideoxynucleotide chain-terminating method in five pancreatic cell lines (human CAPAN2, CAV, MIA Paca2, PANCi, and hamster H2T) on which lovastatin exerted a growth-inhibitory effect. These codons play a major role in tumorigenic mutation of ras genes. Lovastatin inhibited cell growth by 99% (MIA), 97% (H2T), 78% (CAV), 41% (CAPAN2), and 23% (PANC1), respectively, when cells were treated with 2.5 micrograms/ml lovastatin for 6 days. Activating point mutations were found in codon 12 of the K-ras gene (wild type:GGT) in MIA (GTT), H2T (GAT), CAPAN2 (TGT), and PANC1 (GAT) but not in CAV. In addition, the CAV cell line did not have a mutation in either H- or N-ras genes. Lovastatin inhibited the growth of CAV cells even though this cell line did not have ras mutation, suggesting that lovastatin inhibition of pancreatic cancer cell growth is not directly dependent on the presence of ras mutation.
Insights
Lovastatin, a cholesterol synthesis inhibitor, reduces pancreatic cancer cell growth. This study found lovastatin inhibits cancer cell proliferation regardless of ras gene mutations, suggesting a broader therapeutic potential.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Lovastatin inhibits cholesterol synthesis and pancreatic cancer cell growth.
- RAS proteins, crucial for cell signaling, require farnesyl for activation, a cholesterol synthesis intermediate.
- K-ras gene mutations are common in pancreatic cancers.
Purpose of the Study:
- To investigate if lovastatin's growth inhibition of pancreatic cancer cells depends on ras gene mutations.
- To determine the role of RAS protein activation in lovastatin's anti-cancer effects.
Main Methods:
- Examined codons 12/13 and 61 of ras genes in five pancreatic cell lines using dideoxynucleotide chain-terminating sequencing.
- Assessed lovastatin's growth-inhibitory effects on these cell lines at a concentration of 2.5 micrograms/ml over 6 days.
Main Results:
- Lovastatin significantly inhibited growth in MIA (99%), H2T (97%), CAV (78%), CAPAN2 (41%), and PANC1 (23%) cell lines.
- Activating K-ras mutations were identified in MIA, H2T, CAPAN2, and PANC1 cell lines, but not in CAV.
- Lovastatin inhibited growth in the CAV cell line, which lacked ras mutations, indicating the effect is not solely dependent on ras mutation status.
Conclusions:
- Lovastatin inhibits pancreatic cancer cell growth through mechanisms potentially independent of ras gene mutations.
- These findings suggest lovastatin may have therapeutic applications in a broader range of pancreatic cancers, including those without specific ras mutations.