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Autotaxin, lysophosphatidate and taxol resistance

Authors: Samadi, Nasser;

Autotaxin, lysophosphatidate and taxol resistance

Abstract

First-line treatment of breast and other cancers with Taxol is compromised by resistance in up to 40% of patients. To improve chemotherapy, it is vital to understand how Taxol resistance develops and to overcome this. Autotaxin (ATX) promotes cancer cell survival, growth, migration, invasion and metastasis. ATX converts extracellular lysophosphatidylcholine (LPC) into lysophosphatidate (LPA). As these lipids have been reported to affect cell signaling through their own G-protein-coupled receptors, ATX could modify the balance of this signaling. Also, ATX affects cell adhesion independently of its catalytic activity, We first investigated the interactions of ATX, LPC and LPA on the apoptotic effects of Taxol, which is commonly used in breast cancer treatment. LPC had no significant effect on Taxol-induced apoptosis in MCF-7 breast cancer cells, which do not secrete significant ATX. Addition of incubation medium from MDA-MB-435 melanoma cells, which secrete ATX, or recombinant ATX enabled LPC to inhibit Taxol-induced apoptosis of MCF-7 cells. Inhibiting ATX activity blocked this protection against apoptosis. We conclude that LPC has no significant effect in protecting MCF-7 cells against Taxol treatment unless it is converted to LPA by ATX. LPA strongly antagonized Taxol-induced apoptosis through stimulating phosphatidylinositol 3-kinase and inhibiting ceramide formation. LPA also partially reversed the Taxol-induced arrest in the G2/M phase of the cell cycle. Then, we described a novel action of LPA, which by activating phosphatidylinositol 3-kinase increases the expression of glycogen synthase kinase-3ß and survivin. Survivin is an anti-apoptotic protein, which also increases the dynamicity of microtubules. Survivin decreased the effectiveness of Taxol in stabilizing microtubules and enabled MCF-7 breast cancer cells to escape from Taxol-induced arrest in G2/M and consequent cell death. Our work showed that inhibiting ATX activity and LPA-mediated signaling can reverse the resistance to Taxol-induced cell death. Our results support the hypothesis that therapeutic inhibition of ATX activity, which results in less LPA production, or inhibition of LPA signalling could improve the efficacy of Taxol as a chemotherapeutic agent for cancer treatment.

Country
Canada
Related Organizations
Keywords

Lysophosphatidate, Autotaxin, Taxol, Chemoresistance

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
Average
Related to Research communities
Cancer Research
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