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Effects of long-chain fatty amines on the growth of ras-transformed NIH 3T3 cells
R Kothapalli1, E M Lui, N Guthrie
1Department of Biochemistry, University of Western Ontario, London, Canada.
Abstract:
A number of aliphatic primary amines were tested for their effects on the growth of ras-transformed NIH 3T3 cells (PAP2 cells), as measured by incorporation of tritiated thymidine into DNA. Long-chain, saturated amines (C12 to C18) were growth inhibitory, whereas short-chain amines (C6, C8) were not. Farnesylamine, a branched-chain, unsaturated amine (C15), had an IC50 of 6.9 microM compared to IC50 values of 13.1 to 45.8 microM for straight-chain, saturated amines. Oleylamine, with an IC50 of 0.1 microM, was the most potent inhibitor. The long-chain amines, but not the short-chain amines, were also effective inhibitors of protein kinase C, assayed in vitro in a cell-free system. In addition, studies with indo-1-loaded PAP2 cells showed that long-chain amines induced a reversible rise in intracellular free Ca2+ concentration. Growth inhibition by the amines was positively correlated with this effect, suggesting that factors other than protein kinase C may be involved in the inhibition of growth of PAP2 cells by long-chain amines.
Insights
Long-chain aliphatic amines inhibit ras-transformed cell growth by affecting intracellular calcium levels. Shorter amines and protein kinase C inhibition were not significantly correlated with this growth effect.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Ras-transformed cells, such as PAP2 cells, exhibit uncontrolled proliferation.
- Aliphatic primary amines represent a class of compounds with potential biological activities.
- Understanding the mechanisms of growth inhibition in cancer cells is crucial for therapeutic development.
Purpose of the Study:
- To investigate the effects of various aliphatic primary amines on the growth of ras-transformed NIH 3T3 cells (PAP2 cells).
- To explore the potential mechanisms underlying amine-induced growth inhibition, including effects on protein kinase C and intracellular calcium levels.
Main Methods:
- Cell growth was assessed by measuring tritiated thymidine incorporation into DNA.
- Inhibition of protein kinase C was assayed in vitro using a cell-free system.
- Intracellular free Ca2+ concentration was measured in indo-1-loaded PAP2 cells.
Main Results:
- Long-chain, saturated aliphatic amines (C12-C18) exhibited significant growth inhibitory effects on PAP2 cells.
- Short-chain amines (C6, C8) did not inhibit cell growth.
- Farnesylamine (C15, branched, unsaturated) and oleylamine (most potent) showed significant IC50 values, with oleylamine being the most effective inhibitor.
- Long-chain amines inhibited protein kinase C in vitro and induced a reversible rise in intracellular free Ca2+ concentration.
- Growth inhibition correlated positively with the rise in intracellular Ca2+.
Conclusions:
- Long-chain aliphatic amines are potent inhibitors of ras-transformed cell growth.
- The growth inhibitory effects are associated with an increase in intracellular free Ca2+ concentration.
- While long-chain amines inhibit protein kinase C, the Ca2+ flux appears to be a more direct correlate of growth inhibition, suggesting additional or alternative mechanisms may be involved.