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Choline kinase inhibitors as a novel approach for antiproliferative drug design
R Hernández-Alcoceba1, L Saniger, J Campos
1Instituto de Investigaciones Biomédicas, CSIC, Madrid, Spain.
Abstract:
Recent progress in deciphering the molecular basis of carcinogenesis is of utmost importance to the development of new anticancer strategies. To this end, it is essential to understand the regulation of both normal cell proliferation and its alterations in cancer cells. We have previously demonstrated that in ras-transformed cells there is an increased level of phosphorylcholine (PCho) resulting from a constitutive activation on choiline kinase (ChoK). The importance of ChoK for the regulation of cell proliferation has also been proposed since an inhibitor for this enzyme, hemicholinium-3 (HC-3), drastically reduces entry into the S phase after stimulation with growth factors. Here we report the synthesis of several new compounds which are highly specific inhibitors for ChoK, with up to 1000-fold or 600-fold increased inhibitory activity, compared to HC-3 under ex vivo or in vitro conditions respectively. These novel compounds also drastically reduce entry into the S phase after stimulation with specific growth factors. A more profound inhibition of cell proliferation was observed in ras-, src- and mos-transformed cells in the presence of ChoK inhibitors, compared to their parental, untransformed NIH3T3 cells. By contrast, this effect was not observed in fos-transformed cells. While ras, src and mos transformation is associated with elevated levels of ChoK activity, fos-induced transformation does not affect ChoK activity. The inhibitory effect on proliferation of the new compounds correlates with their ability to inhibit the production of phosphorylcholine in whole cells, a proposed novel second messenger for cell proliferation. These results strongly support a critical role of choline kinase in the regulation of cell growth and makes this enzyme a novel target for the design of new antiproliferative and anticancer drugs.
Insights
New choline kinase (ChoK) inhibitors show potent anticancer activity by blocking cell proliferation. These compounds target elevated phosphorylcholine production in cancer cells, offering a promising new strategy for drug development.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Understanding cancer cell proliferation is crucial for developing new anticancer strategies.
- Choline kinase (ChoK) activity and phosphorylcholine (PCho) levels are elevated in ras-transformed cells.
- Previous studies suggest ChoK regulates cell proliferation, as inhibitors like hemicholinium-3 (HC-3) reduce S phase entry.
Purpose of the Study:
- To synthesize and characterize novel, highly specific inhibitors of choline kinase (ChoK).
- To evaluate the efficacy of these new inhibitors in blocking cancer cell proliferation.
- To investigate the role of ChoK and PCho in different types of oncogenic transformation.
Main Methods:
- Synthesis of novel, specific ChoK inhibitors with significantly enhanced activity compared to HC-3.
- Assessment of inhibitor effects on cell proliferation, specifically S phase entry, after growth factor stimulation.
- Comparison of inhibitor efficacy in ras-, src-, mos-, and fos-transformed cells versus parental NIH3T3 cells.
- Measurement of PCho production in whole cells.
Main Results:
- Novel compounds exhibited 1000-fold (ex vivo) and 600-fold (in vitro) greater ChoK inhibitory activity than HC-3.
- These inhibitors significantly reduced S phase entry upon growth factor stimulation.
- Profound inhibition of proliferation was observed in ras-, src-, and mos-transformed cells, but not fos-transformed cells.
- Elevated ChoK activity correlated with ras, src, and mos transformation, but not fos transformation.
- Inhibitor efficacy correlated with reduced PCho production, suggesting PCho's role as a second messenger.
Conclusions:
- Choline kinase (ChoK) plays a critical role in regulating cell growth and proliferation.
- Novel, potent ChoK inhibitors effectively reduce cancer cell proliferation by inhibiting PCho production.
- ChoK represents a promising novel molecular target for the development of new antiproliferative and anticancer drugs.