Structure‐function relationship of new anthralin derivatives assayed for growth inhibition and cytotoxicity in human keratinocyte cultures

Abstract

HaCaT keratinocyte cultures were exposed to twelve hydrophilic anthralin derivatives 1 to 12 with substituents at C-l and C-8 of the anthrone skeleton, of one H at C-10 and of both H's at C-10 by lacton rings ( fig. 1). After 3 uM treatment growth was determined by cellular protein content, ^-thymidineand 14 C-amino-acid-uptake and cytotoxicity by the release of cytoplasmic LDH into the culture medium.-In comparison to acetone control (100%) anthralin suppressed mean protein content, as well as DNA-and protein-synthesis to 33, 28, and 21%, respectively, and the drug revealed an enzyme release of 660%. In relation to the parent drug we found similar cell growth inhibitory effects of compounds 4, 6, 8, 9, 10, and 12. Deriv. 4, 8, and 10 were, however, to some extent less cytotoxic than anthralin, whereas deriv. 6, 9, and 12 were in the same range. An extreme suppression of growth parameters which differed from the anthralin effect by a factor 0.5-0.8 was caused by deriv. 11, showing the same cytotoxicity. Deriv. 1, 2, 3,5, and 7 did not demonstrate any cytotoxicity. Concerning growth parameters, deriv. 2 induced a slight stimulation, deriv. 3 and 7 were completely ineffective, deriv. 1 and 5 induced slightly to moderately inhibited proliferation but both being much less effective than anthralin. These data indicate that the "minimum structure" concept by Krebs and Schaltegger -claiming l-hydroxy-9-anthrone as a precondition for clinical antipsoriatic potency -is not valid at least in cell-biological tests and point toward possible usefulness of some experimental model compounds as alternative antipsoriatics.

Effect of Fumaric Acid, Its Dimethylester, and Topical Antipsoriatic Drugs on Epidermal Differentiation in the Mouse Tail Model

“…It has to be considered, however, that the molecular concentration of the C4-lactone ointment was distinctly lower than that of the dithranol ointment (16 versus 22 mM). In a previous comparative study of dithranol and various derivatives of dithranol on HaCaT keratinocytes were found that C4-lactone, an anthrone substituted at C-10 by a lactone ring, gave the most favorable results concerning high antiproliferative activity and low cytotoxicity [13]. The present study con firms that C4-lactone is relatively effective on epidermal differentiation at equal concentra tions of dithranol, but possibly less toxic or irritative, as indicated by the lack in increase of epidermal thickness.…”

“…In previous studies in vitro we demonstrated that of the fumaric acid deriva tives, the fumaric acid dimethylester and of the dithranol compounds, C4-lactone were the most effective on kératinocyte prolifera tion at subtoxic concentrations [13,14], Therefore, in the present study we compare the effects of fumaric acid, fumaric acid di methylester, and C4-lactone with that of clas sic topical antipsoriatics on kératinocyte mat uration in vivo.…”

Dithranol and Dimethylfumarate Suppress the Interferon-γ-Induced Up-Regulation of Cytokeratin 17 as a Putative Psoriasis Autoantigen in vitro

“…We used dithranol at a rather low concentration of 0.3 ÌM, which in our previous experiments had been found to act in an antiproliferative manner without any direct cytotoxicity [24,30,31]. At this concentration a 2-hour preincubation with dithranol significantly reduced the above-mentioned up-regu- Bonnekoh/Böckelmann/Ambach/ Gollnick lation of K17 by subsequent incubation with 25 U IFN-Á/ml for 72 h. Thus, there is evidence to suggest that part of dithranol's antipsoriatic activity could derive from an at least partial shutdown of the expression of K17 containing a presumptive psoriasis-relevant autoantigen structure.…”

Optimized Visualization and PCR Reamplification of Differentially Displayed cDNA Bands Detected by Silver Staining in Polyacrylamide Gels as Established in the Model of Dithranol-Treated Keratinocytes

“…In the present study, we used hyperproliferative human HaCaT keratinocytes, representing an in vitro model for disturbed epidermopoiesis in psoriasis [19], treated by the antipsoriatic drug dithranol [20] as a test system to establish an optimized non-radioactive RT-PCR/DD. In this context, as modifications from known procedures, we now describe (1) a highly sensitive silver staining for cDNA separated by PAGE and (2) a compatible, highly efficient procedure to elute cDNA from silver-stained gels for subsequent PCR reamplification.…”