title: Comparative cytotoxicity of chelidonine and homochelidonine, the dimethoxy analogues isolated from Chelidonium majus L. (Papaveraceae), against human leukemic and lung carcinoma cells.
abstract: BACKGROUND
  The search for new anticancer compounds is a crucial element of natural products research.
  
  
  OBJECTIVE
  In this study the effects of naturally occurring homochelidonine in comparison to chelidonine on cell cycle progression and cell death in leukemic T-cells with different p53 status are described.
  
  
  METHODS
  The mechanism of cytotoxic, antiproliferative, apoptosis-inducing effects and the effect on expressions of cell cycle regulatory proteins was investigated using XTT assay, Trypan blue exclusion assay, flow cytometry, Western blot analysis, xCELLigence, epi-fluorescence and 3D super resolution microscopy. A549 cells were used for xCELLigence, clonogenic assay and for monitoring microtubule stability.
  
  
  RESULTS
  We found that homochelidonine and chelidonine displayed significant cytotoxicity in examined blood cancer cells with the exception of HEL 92.1.7 and U-937 exposed to homochelidonine. Unexpectedly, homochelidonine and chelidonine-induced cytotoxicity was more pronounced in Jurkat cells contrary to MOLT-4 cells. Homochelidonine showed an antiproliferative effect on A549 cells but it was less effective compared to chelidonine. Biphasic dose-depended G1 and G2/M cell cycle arrest along with the population of sub-G1 was found after treatment with homochelidonine in MOLT-4 cells. In variance thereto, an increase in G2/M cells was detected after treatment with homochelidonine in Jurkat cells. Treatment with chelidonine induced cell cycle arrest in the G2/M cell cycle in both MOLT-4 and Jurkat cells. MOLT-4 and Jurkat cells treated with homochelidonine and chelidonine showed features of apoptosis such as phosphatidylserine exposure, a loss of mitochondrial membrane potential and an increase in the caspases -3/7, -8 and -9. Western blots indicate that homochelidonine and chelidonine exposure activates Chk1 and Chk2. Studies conducted with fluorescence microscopy demonstrated that chelidonine and homochelidonine inhibit tubulin polymerization in A549 cells.
  
  
  CONCLUSIONS
  Collectively, the data indicate that chelidonine and homochelidonine are potent inducers of cell death in cancer cell lines, highlighting their potential relevance in leukemic cells.
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10, Czech Republic. Electronic address: radim.havelek@upce.cz.
authors.forename: Radim
authors.initials: R
authors.lastname: Havelek
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Simkova 870, Hradec Kralove 500 38, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Seifrtova
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Kralovec
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10, Czech Republic.
authors.forename: Eliska
authors.initials: E
authors.lastname: Krocova
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Tejkalova
authors.affiliation: Flow Cytometry and Light Microscopy, Institute of Molecular Genetics of the ASCR, Videnska 1083, Prague 142 20, Czech Republic.
authors.forename: Ivan
authors.initials: I
authors.lastname: Novotny
authors.affiliation: ADINACO Research group, Department of Pharmaceutical Botany and Ecology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 500 05, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Cahlikova
authors.affiliation: ADINACO Research group, Department of Pharmaceutical Botany and Ecology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 500 05, Czech Republic.
authors.forename: Marcela
authors.initials: M
authors.lastname: Safratova
authors.affiliation: ADINACO Research group, Department of Pharmaceutical Botany and Ecology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 500 05, Czech Republic.
authors.forename: Lubomir
authors.initials: L
authors.lastname: Opletal
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Bilkova
authors.affiliation: Department of Radiobiology, Faculty of Military Health Sciences, University of Defence in Brno, Trebesska 1575, Hradec Kralove 500 01, Czech Republic.
authors.forename: Jirina
authors.initials: J
authors.lastname: Vavrova
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Simkova 870, Hradec Kralove 500 38, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Rezacova
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053119:Benzophenanthridines / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects; D028281:Chelidonium / Q000737:chemistry*; D006801:Humans; D019169:Jurkat Cells; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects
chemical_list: D053119:Benzophenanthridines; D001600:Berberine Alkaloids; C062047:chelidonine; D020169:Caspases; C517745:homochelidonine
keywords: Apoptosis; Biphasic cell cycle arrest; Homochelidonine; Mitotic block