Multiple biological effects of inhibitors of arachidonic acid metabolism on human keratinocytes.
BACKGROUND
Various compounds that inhibit processing of arachidonic acid (AA) are being intensively tested for their antitumour activity. However, the mechanisms responsible for such activity remain rather elusive. To approach this issue, we examined the effects of several structurally different inhibitors of AA metabolism in the human keratinocyte HaCaT cell line.


METHODS
Several parameters were determined in HaCaT cells exposed to increasing concentrations of the inhibitors for 24 and/or 48 h. These included (1) oxidoreductase activity, total protein mass and cell cycle distribution to assess cell proliferation, (2) degradation of PARP protein to assess apoptosis, and (3) cell morphology, distribution of F-actin and expression of cytokeratins and E-cadherin to evaluate changes in differentiation status.


RESULTS
While eicosatetraynoic acid (ETYA), nordihydroguaiaretic acid (NDGA), esculetin and MK-886 reduced proliferation of HaCaT cells, the cyclooxygenase inhibitors indomethacin and piroxicam had no such effects. Esculetin and NDGA arrested cells in S phase, and ETYA and MK-886 delayed cell progression through G(1) phase. Higher concentrations of NDGA, MK886 and/or ETYA caused cleavage of PARP. No changes in the expression of cytokeratins and E-cadherin were observed upon treatment with any of the inhibitors. However, esculetin induced redistribution of F-actin accompanied by increased cell adhesion and size.


CONCLUSIONS
Our findings indicate that, in addition to their ability to inhibit cell proliferation and to induce apoptosis, lipoxygenase inhibitors and/or ETYA may also elicit other important physiological responses in HaCaT keratinocytes.
Pacherník
Jirí
J
Institute of Biophysics, Academy of Science of the Czech Republic, Brno, Czech Republic.
Hampl
Ales
A
Soucek
Karel
K
Kovaríková
Martina
M
Andrysík
Zdenek
Z
Hofmanová
Jirina
J
Kozubík
Alois
A
D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D016718:Arachidonic Acid / Q000037:antagonists & inhibitors*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D014468:Umbelliferones / Q000494:pharmacology; D002722:Chlorobenzenes
D015117:5,8,11,14-Eicosatetraynoic Acid; D016718:Arachidonic Acid; D016861:Cyclooxygenase Inhibitors; D007211:Indoles; D016859:Lipoxygenase Inhibitors; D014468:Umbelliferones; C060893:MK-886; D002722:Chlorobenzenes; C007628:esculetin