12-Lipoxygenase in A431 cells: Genetic identity, modulation of expression, and intracellular localization

Wolfgang Hagmann, Xiang Gao, Joszef Timar, Yong Q. Chen, Anja Rose Strohmaier, Chris Fahrenkopf, David Kagawa, Miu Lee, Alex Zacharek, Kenneth V. Honn

Research output: Article

28 Citations (Scopus)

Abstract

Human A431 epidermoid carcinoma cells express 12-lipoxygenase enzymatic activity. However, the isoform identity based on cDNA sequence data is not known. Further, the simultaneous characterization of the intracellular distribution of 12-lipoxygenase protein and activity is lacking. Here we report that the cDNA sequence from RT-PCR-amplified 12-lipoxygenase mRNA is identical with the platelet-type 12-lipoxygenase isoform, and the leukocyte- type isoform of 12-lipoxygenase is not expressed in A431 cells. The predominant amount (78%) of 12-lipoxygenase protein resides in the cytosol. In contrast, the predominant (98%) 12-lipoxygenase activity is localized in the membrane fraction. Western blot and immunofluorescence data demonstrate that epidermal growth factor increases total cellular 12-lipoxygenase protein and enhances the association of 12-lipoxygenase protein with perinuclear or nuclear membrane sites. In addition, epidermal growth factor stimulates 12- lipoxygenase activity resulting in generation of 12(S)- hydroxyeicosatetraenoic acid from cellular arachidonate. In contrast, both 12-lipoxygenase protein and activity decrease approximately 80% within 24 h during serum starvation. The recovery of 12-lipoxygenase expression in serum- deprived cells can be induced by readdition of epidermal growth factor or serum. Further, the basal expression of 12-lipoxygenase depends on signal pathways requiring protein tyrosine kinase activity, since genistein, herbimycin A, and tyrphostin 25 reduce the expression of 12-lipoxygenase protein in A431 cells.

Original languageEnglish
Pages (from-to)197-205
Number of pages9
JournalExperimental Cell Research
Volume228
Issue number2
DOIs
Publication statusPublished - nov. 1 1996

ASJC Scopus subject areas

  • Cell Biology

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    Hagmann, W., Gao, X., Timar, J., Chen, Y. Q., Strohmaier, A. R., Fahrenkopf, C., Kagawa, D., Lee, M., Zacharek, A., & Honn, K. V. (1996). 12-Lipoxygenase in A431 cells: Genetic identity, modulation of expression, and intracellular localization. Experimental Cell Research, 228(2), 197-205. https://doi.org/10.1006/excr.1996.0317