TY - JOUR A1 - Boulos, Joelle C. A1 - Saeed, Mohamed E. M. A1 - Chatterjee, Manik A1 - Bülbül, Yagmur A1 - Crudo, Francesco A1 - Marko, Doris A1 - Munder, Markus A1 - Klauck, Sabine M. A1 - Efferth, Thomas T1 - Repurposing of the ALK inhibitor crizotinib for acute leukemia and multiple myeloma cells JF - Pharmaceuticals N2 - Crizotinib was a first generation of ALK tyrosine kinase inhibitor approved for the treatment of ALK-positive non-small-cell lung carcinoma (NSCLC) patients. COMPARE and cluster analyses of transcriptomic data of the NCI cell line panel indicated that genes with different cellular functions regulated the sensitivity or resistance of cancer cells to crizotinib. Transcription factor binding motif analyses in gene promoters divulged two transcription factors possibly regulating the expression of these genes, i.e., RXRA and GATA1, which are important for leukemia and erythroid development, respectively. COMPARE analyses also implied that cell lines of various cancer types displayed varying degrees of sensitivity to crizotinib. Unexpectedly, leukemia but not lung cancer cells were the most sensitive cells among the different types of NCI cancer cell lines. Re-examining this result in another panel of cell lines indeed revealed that crizotinib exhibited potent cytotoxicity towards acute myeloid leukemia and multiple myeloma cells. P-glycoprotein-overexpressing CEM/ADR5000 leukemia cells were cross-resistant to crizotinib. NCI-H929 multiple myeloma cells were the most sensitive cells. Hence, we evaluated the mode of action of crizotinib on these cells. Although crizotinib is a TKI, it showed highest correlation rates with DNA topoisomerase II inhibitors and tubulin inhibitors. The altered gene expression profiles after crizotinib treatment predicted several networks, where TOP2A and genes related to cell cycle were downregulated. Cell cycle analyses showed that cells incubated with crizotinib for 24 h accumulated in the G\(_2\)M phase. Crizotinib also increased the number of p-H3(Ser10)-positive NCI-H929 cells illustrating crizotinib's ability to prevent mitotic exit. However, cells accumulated in the sub-G\(_0\)G\(_1\) fraction with longer incubation periods, indicating apoptosis induction. Additionally, crizotinib disassembled the tubulin network of U2OS cells expressing an α-tubulin-GFP fusion protein, preventing migration of cancer cells. This result was verified by in vitro tubulin polymerization assays. In silico molecular docking also revealed a strong binding affinity of crizotinib to the colchicine and Vinca alkaloid binding sites. Taken together, these results demonstrate that crizotinib destabilized microtubules. Additionally, the decatenation assay showed that crizotinib partwise inhibited the catalytic activity of DNA topoisomerase II. In conclusion, crizotinib exerted kinase-independent cytotoxic effects through the dual inhibition of tubulin polymerization and topoisomerase II and might be used to treat not only NSCLC but also multiple myeloma. KW - acute myeloid leukemia KW - drug repurposing KW - multiple myeloma KW - network pharmacology KW - transcriptomics KW - tyrosine kinase inhibitors Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250258 SN - 1424-8247 VL - 14 IS - 11 ER - TY - JOUR A1 - Guth, Sabine A1 - Hüser, Stephanie A1 - Roth, Angelika A1 - Degen, Gisela A1 - Diel, Patrick A1 - Edlund, Karolina A1 - Eisenbrand, Gerhard A1 - Engel, Karl-Heinz A1 - Epe, Bernd A1 - Grune, Tilman A1 - Heinz, Volker A1 - Henle, Thomas A1 - Humpf, Hans-Ulrich A1 - Jäger, Henry A1 - Joost, Hans-Georg A1 - Kulling, Sabine E. A1 - Lampen, Alfonso A1 - Mally, Angela A1 - Marchan, Rosemarie A1 - Marko, Doris A1 - Mühle, Eva A1 - Nitsche, Michael A. A1 - Röhrdanz, Elke A1 - Stadler, Richard A1 - van Thriel, Christoph A1 - Vieths, Stefan A1 - Vogel, Rudi F. A1 - Wascher, Edmund A1 - Watzl, Carsten A1 - Nöthlings, Ute A1 - Hengstler, Jan G. T1 - Contribution to the ongoing discussion on fluoride toxicity JF - Archives of Toxicology N2 - Since the addition of fluoride to drinking water in the 1940s, there have been frequent and sometimes heated discussions regarding its benefits and risks. In a recently published review, we addressed the question if current exposure levels in Europe represent a risk to human health. This review was discussed in an editorial asking why we did not calculate benchmark doses (BMD) of fluoride neurotoxicity for humans. Here, we address the question, why it is problematic to calculate BMDs based on the currently available data. Briefly, the conclusions of the available studies are not homogeneous, reporting negative as well as positive results; moreover, the positive studies lack control of confounding factors such as the influence of well-known neurotoxicants. We also discuss the limitations of several further epidemiological studies that did not meet the inclusion criteria of our review. Finally, it is important to not only focus on epidemiological studies. Rather, risk analysis should consider all available data, including epidemiological, animal, as well as in vitro studies. Despite remaining uncertainties, the totality of evidence does not support the notion that fluoride should be considered a human developmental neurotoxicant at current exposure levels in European countries. KW - pharmacology/toxicology KW - occupational medicine/industrial medicine KW - environmental health KW - biomedicine, general Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-307161 SN - 0340-5761 SN - 1432-0738 VL - 95 IS - 7 ER - TY - JOUR A1 - Rychlik, Michael A1 - Humpf, Hans-Ulrich A1 - Marko, Doris A1 - Dänicke, Sven A1 - Mally, Angela A1 - Berthiller, Franz A1 - Klaffke, Horst A1 - Lorenz, Nicole T1 - Proposal of a comprehensive definition of modified and other forms of mycotoxins including “masked” mycotoxins JF - Mycotoxin Research N2 - As the term "masked mycotoxins" encompasses only conjugated mycotoxins generated by plants and no other possible forms of mycotoxins and their modifications, we hereby propose for all these forms a systematic definition consisting of four hierarchic levels. The highest level differentiates the free and unmodified forms of mycotoxins from those being matrix-associated and from those being modified in their chemical structure. The following lower levels further differentiate, in particular, "modified mycotoxins" into "biologically modified" and "chemically modified" with all variations of metabolites of the former and dividing the latter into "thermally formed" and "non-thermally formed" ones. To harmonize future scientific wording and subsequent legislation, we suggest that the term "modified mycotoxins" should be used in the future and the term "masked mycotoxins" to be kept for the fraction of biologically modified mycotoxins that were conjugated by plants. KW - definition KW - mycotoxins KW - masked mycotoxins KW - modified mycotoxins KW - hidden mycotoxins KW - mycotoxin derivates KW - mycotoxin metabolites KW - conjugated mycotoxins Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121240 VL - 30 IS - 4 ER -