Latest Publications

@article{drapela_chk1_2020,

title = {The CHK1 inhibitor MU380 significantly increases the sensitivity of human docetaxel-resistant prostate cancer cells to gemcitabine through the induction of mitotic catastrophe.},

author = {Stanislav Drápela and Prashant Khirsariya and Wytske M. Weerden and Radek Fedr and Tereza Suchánková and Diana Búzová and Jan Červený and Aleš Hampl and Martin Puhr and William R. Watson and Zoran Culig and Lumír Krejčí and Kamil Paruch and Karel Souček},

doi = {10.1002/1878-0261.12756},

issn = {1878-0261 1574-7891},

year  = {2020},

date = {2020-10-01},

journal = {Molecular oncology},

volume = {14},

number = {10},

pages = {2487–2503},

abstract = {As treatment options for patients with incurable metastatic castration-resistant prostate cancer (mCRPC) are considerably limited, novel effective therapeutic options are needed. Checkpoint kinase 1 (CHK1) is a highly conserved protein kinase implicated in the DNA damage response (DDR) pathway that prevents the accumulation of DNA damage and controls regular genome duplication. CHK1 has been associated with prostate cancer (PCa) induction, progression, and lethality; hence, CHK1 inhibitors SCH900776 (also known as MK-8776) and the more effective SCH900776 analog MU380 may have clinical applications in the therapy of PCa. Synergistic induction of DNA damage with CHK1 inhibition represents a promising therapeutic approach that has been tested in many types of malignancies, but not in chemoresistant mCRPC. Here, we report that such therapeutic approach may be exploited using the synergistic action of the antimetabolite gemcitabine (GEM) and CHK1 inhibitors SCH900776 and MU380 in docetaxel-resistant (DR) mCRPC. Given the results, both CHK1 inhibitors significantly potentiated the sensitivity to GEM in a panel of chemo-naïve and matched DR PCa cell lines under 2D conditions. MU380 exhibited a stronger synergistic effect with GEM than clinical candidate SCH900776. MU380 alone or in combination with GEM significantly reduced spheroid size and increased apoptosis in all patient-derived xenograft 3D cultures, with a higher impact in DR models. Combined treatment induced premature mitosis from G1 phase resulting in the mitotic catastrophe as a prestage of apoptosis. Finally, treatment by MU380 alone, or in combination with GEM, significantly inhibited tumor growth of both PC339-DOC and PC346C-DOC xenograft models in mice. Taken together, our data suggest that metabolically robust and selective CHK1 inhibitor MU380 can bypass docetaxel resistance and improve the effectiveness of GEM in DR mCRPC models. This approach might allow for dose reduction of GEM and thereby minimize undesired toxicity and may represent a therapeutic option for patients with incurable DR mCRPC.},

note = {Place: United States},

keywords = {*Mitosis/drug effects, Animals, castration-resistant prostate cancer, Cell Death/drug effects, Cell Line, Cell Proliferation/drug effects, Checkpoint Kinase 1, Checkpoint Kinase 1/*antagonists & inhibitors/metabolism, Deoxycytidine/*analogs & derivatives/pharmacology, Docetaxel resistance, Docetaxel/*pharmacology, Drug resistance, gemcitabine, Humans, Male, Mice, mitotic catastrophe, MU380, Neoplasm/*drug effects, Piperidines/chemistry/*pharmacology, Prostatic Neoplasms/*pathology, Pyrazoles/chemistry/*pharmacology, Pyrimidines/chemistry/*pharmacology, S Phase/drug effects, SCID, Tumor, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}

@article{boudny_novel_2019,

title = {Novel CHK1 inhibitor MU380 exhibits significant single-agent activity in TP53-mutated chronic lymphocytic leukemia cells.},

author = {Miroslav Boudny and Jana Zemanova and Prashant Khirsariya and Marek Borsky and Jan Verner and Jana Cerna and Alexandra Oltova and Vaclav Seda and Marek Mraz and Josef Jaros and Zuzana Jaskova and Michaela Spunarova and Yvona Brychtova and Karel Soucek and Stanislav Drapela and Marie Kasparkova and Jiri Mayer and Kamil Paruch and Martin Trbusek},

doi = {10.3324/haematol.2018.203430},

issn = {1592-8721 0390-6078},

year  = {2019},

date = {2019-12-01},

journal = {Haematologica},

volume = {104},

number = {12},

pages = {2443–2455},

abstract = {Introduction of small-molecule inhibitors of B-cell receptor signaling and BCL2 protein significantly improves therapeutic options in chronic lymphocytic leukemia. However, some patients suffer from adverse effects mandating treatment discontinuation, and cases with TP53 defects more frequently experience early progression of the disease. Development of alternative therapeutic approaches is, therefore, of critical importance. Here we report details of the anti-chronic lymphocytic leukemia single-agent activity of MU380, our recently identified potent, selective, and metabolically robust inhibitor of checkpoint kinase 1. We also describe a newly developed enantioselective synthesis of MU380, which allows preparation of gram quantities of the substance. Checkpoint kinase 1 is a master regulator of replication operating primarily in intra-S and G(2)/M cell cycle checkpoints. Initially tested in leukemia and lymphoma cell lines, MU380 significantly potentiated efficacy of gemcitabine, a clinically used inducer of replication stress. Moreover, MU380 manifested substantial single-agent activity in both TP53-wild type and TP53-mutated leukemia and lymphoma cell lines. In chronic lymphocytic leukemia-derived cell lines MEC-1, MEC-2 (both TP53-mut), and OSU-CLL (TP53-wt) the inhibitor impaired cell cycle progression and induced apoptosis. In primary clinical samples, MU380 used as a single-agent noticeably reduced the viability of unstimulated chronic lymphocytic leukemia cells as well as those induced to proliferate by anti-CD40/IL-4 stimuli. In both cases, effects were comparable in samples harboring p53 pathway dysfunction (TP53 mutations or ATM mutations) and TP53-wt/ATM-wt cells. Lastly, MU380 also exhibited significant in vivo activity in a xenotransplant mouse model (immunodeficient strain NOD-scid IL2Rγ(null) ) where it efficiently suppressed growth of subcutaneous tumors generated from MEC-1 cells.},

note = {Place: Italy},

keywords = {*Drug Synergism, *Mutation, Animals, Antimetabolites, Antineoplastic/pharmacology, Apoptosis, B-Cell/*drug therapy/genetics/pathology, Biomarkers, Cell Cycle, Cell Proliferation, Checkpoint Kinase 1/*antagonists & inhibitors, Chronic, Cultured, Deoxycytidine/analogs & derivatives/pharmacology, Drug resistance, Female, gemcitabine, Gene Expression Regulation, Humans, Inbred NOD, Leukemia, Lymphocytic, Mice, Neoplasm/drug effects, Neoplastic/*drug effects, Piperidines/*pharmacology, Protein Kinase Inhibitors/pharmacology, Pyrazoles/*pharmacology, Pyrimidines/*pharmacology, SCID, Tumor Cells, Tumor Suppressor Protein p53/*genetics, Tumor/genetics, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}

@article{vargova_hypericin_2018,

title = {Hypericin affects cancer side populations via competitive inhibition of BCRP.},

author = {Jana Vargová and Jaromír Mikeš and Rastislav Jendželovský and Lucia Mikešová and Barbora Kuchárová and Ľubomír Čulka and Radek Fedr and Ján Remšík and Karel Souček and Alois Kozubík and Peter Fedoročko},

doi = {10.1016/j.biopha.2018.01.074},

issn = {1950-6007 0753-3322},

year  = {2018},

date = {2018-03-01},

journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie},

volume = {99},

pages = {511–522},

abstract = {OBJECTIVE: Cancer stem-like cells (CSLCs) are considered a root of tumorigenicity and resistance. However, their identification remains challenging. The use of the side population (SP) assay as a credible marker of CSLCs remains controversial. The SP assay relies on the elevated activity of ABC transporters that, in turn, can be modulated by hypericin (HYP), a photosensitizer and bioactive compound of St. John's Wort (Hypericum perforatum), a popular over-the-counter antidepressant. Here we aimed to comprehensively characterize the SP phenotype of cancer cells and to determine the impact of HYP on these cells. METHODS: Flow cytometry and sorting-based assays were employed, including CD24-, CD44-, CD133-, and ALDH-positivity, clonogenicity, 3D-forming ability, ABC transporter expression and activity, and intracellular accumulation of HYP/Hoechst 33342. The tumorigenic ability of SP, nonSP, and HYP-treated cells was verified by xenotransplantation into immunodeficient mice. RESULTS: The SP phenotype was associated with elevated expression of several investigated transporters and more intensive growth in non-adherent conditions but not with higher clonogenicity, tumorigenicity or ALDH-positivity. Despite stimulated BCRP level and MRP1 activity, HYP reversibly decreased the SP proportion, presumably via competitive inhibition of BCRP. HYP-selected SP cells acquired additional traits of resistance and extensively eliminated HYP. CONCLUSIONS: Our results suggest that SP is not an unequivocal CSLC-marker. However, SP could play an important role in modulating HYP-treatment and serve as a negative predictive tool for HYP-based therapies. Moreover, the use of supplements containing HYP by cancer patients should be carefully considered, due to its proposed effect on drug efflux and complex impact on tumor cells, which have not yet been sufficiently characterized.},

note = {Place: France},

keywords = {ABC transporters, Aldehyde Dehydrogenase/metabolism, Animals, Anthracenes, ATP Binding Cassette Transporter, Biomarkers, Cancer stem-like cells, Carcinogenesis/drug effects/metabolism/pathology, Cell Line, Cellular/drug effects/metabolism/pathology, Clone Cells, Drug resistance, Humans, Hypericin, Member 1/metabolism, Member 2/*metabolism, Mice, Neoplasm Proteins/*metabolism, Neoplasms/*metabolism/*pathology, Neoplastic Stem Cells/drug effects/metabolism/pathology, Perylene/*analogs & derivatives/pharmacology, Phenotype, SCID, Side population, Side-Population Cells/drug effects/*pathology, Spheroids, St. John’s wort, Subfamily B, Subfamily G, Substrate Specificity/drug effects, Survival Analysis, Tumor, Tumor/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{kratochvilova_tumor_2015,

title = {Tumor suppressor candidate 3 (TUSC3) prevents the epithelial-to-mesenchymal transition and inhibits tumor growth by modulating the endoplasmic reticulum stress response in ovarian cancer cells.},

author = {Kateřina Kratochvílová and Peter Horak and Milan Ešner and Karel Souček and Dietmar Pils and Mariam Anees and Erwin Tomasich and František Dráfi and Veronika Jurtíková and Aleš Hampl and Michael Krainer and Petr Vaňhara},

doi = {10.1002/ijc.29502},

issn = {1097-0215 0020-7136},

year  = {2015},

date = {2015-09-01},

journal = {International journal of cancer},

volume = {137},

number = {6},

pages = {1330–1340},

abstract = {Ovarian cancer is one of the most common malignancies in women and contributes greatly to cancer-related deaths. Tumor suppressor candidate 3 (TUSC3) is a putative tumor suppressor gene located at chromosomal region 8p22, which is often lost in epithelial cancers. Epigenetic silencing of TUSC3 has been associated with poor prognosis, and hypermethylation of its promoter provides an independent biomarker of overall and disease-free survival in ovarian cancer patients. TUSC3 is localized to the endoplasmic reticulum in an oligosaccharyl tranferase complex responsible for the N-glycosylation of proteins. However, the precise molecular role of TUSC3 in ovarian cancer remains unclear. In this study, we establish TUSC3 as a novel ovarian cancer tumor suppressor using a xenograft mouse model and demonstrate that loss of TUSC3 alters the molecular response to endoplasmic reticulum stress and induces hallmarks of the epithelial-to-mesenchymal transition in ovarian cancer cells. In summary, we have confirmed the tumor-suppressive function of TUSC3 and identified the possible mechanism driving TUSC3-deficient ovarian cancer cells toward a malignant phenotype.},

note = {Place: United States},

keywords = {Animals, Cell Line, Endoplasmic Reticulum Stress, Endoplasmic Reticulum Stress/*genetics, Epithelial-Mesenchymal Transition/*genetics, epithelial-to-mesenchymal transition, Female, Genes, Heterografts, Humans, Inbred NOD, Membrane Proteins/*genetics, Mice, N33, ovarian cancer, Ovarian Neoplasms/*genetics, SCID, Tumor, Tumor Suppressor, Tumor Suppressor Proteins/*genetics, Tumor Suppressor/physiology, TUSC3},

pubstate = {published},

tppubtype = {article}

}

@article{soucek_fetal_2010,

title = {Fetal colon cell line FHC exhibits tumorigenic phenotype, complex karyotype, and TP53 gene mutation.},

author = {Karel Soucek and Pavla Gajdusková and Marie Brázdová and Martina Hýzd'alová and Lenka Kocí and David Vydra and Radek Trojanec and Zuzana Pernicová and Lenka Lentvorská and Marián Hajdúch and Jirina Hofmanová and Alois Kozubík},

doi = {10.1016/j.cancergencyto.2009.11.009},

issn = {1873-4456 0165-4608},

year  = {2010},

date = {2010-03-01},

journal = {Cancer genetics and cytogenetics},

volume = {197},

number = {2},

pages = {107–116},

abstract = {Stable cell lines obtained by spontaneous immortalization might represent early stages of malignant transformation and be useful experimental models for studies of mechanisms of cancer development. The FHC (fetal human cells) cell line has been established from normal fetal colonic mucosa. Detailed characterization of this cell line and mechanism of spontaneously acquired immortality have not been described yet. Therefore, we characterized the FHC cell line in terms of its tumorigenicity, cytogenetics, and TP53 gene mutation analysis. FHC cells displayed capability for anchorage-independent growth in semisolid media in vitro and formed solid tumors after transplantation into SCID (severe combined immunodeficiency) mice. This tumorigenic phenotype was associated with hypotriploidy and chromosome number ranging from 66 to 69. Results of comparative genetic hybridization arrays showed that most chromosomes included regions of copy number gains or losses. Region 8q23 approximately 8q24.3 (containing, e.g., MYC proto-oncogene) was present in more than 20 copies per nucleus. Moreover, we identified mutation of TP53 gene in codon 273; triplet CGT coding Arg was changed to CAG coding His. Expression of Pro codon 72 polymorphic variant of p53 was also detected. Mutation of TP53 gene was associated with abolished induction of p21(Waf1/Cip1) and MDM-2 proteins and resistance to apoptosis after genotoxic treatment. Because of their origin from normal fetal colon and their relative resistance to the induction of apoptosis, FHC cells can be considered a valuable experimental model for various studies.},

note = {Place: United States},

keywords = {*Genes, Animals, Apoptosis/physiology, Carcinoembryonic Antigen/metabolism, Cell Adhesion/physiology, Cell Growth Processes/physiology, Cell Line, Cell Transformation, Colon/cytology/metabolism/*physiology, Colonic Neoplasms/*genetics/*pathology, Comparative Genomic Hybridization, Cytogenetic Analysis/methods, DNA Damage, DNA Mutational Analysis/methods, Female, Fetus/cytology, Fluorescence, HCT116 Cells, Humans, In Situ Hybridization, Karyotyping, Keratins/metabolism, Mice, Neoplasm Transplantation, Neoplastic/genetics/pathology, p53, Phenotype, Proto-Oncogene Mas, SCID, Signal Transduction, Transformed},

pubstate = {published},

tppubtype = {article}

}