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{simeckova_high_2019,

title = {High Skp2 expression is associated with a mesenchymal phenotype and increased tumorigenic potential of prostate cancer cells.},

author = {Šárka Šimečková and Zuzana Kahounová and Radek Fedr and Ján Remšík and Eva Slabáková and Tereza Suchánková and Jiřina Procházková and Jan Bouchal and Gvantsa Kharaishvili and Milan Král and Petr Beneš and Karel Souček},

doi = {10.1038/s41598-019-42131-y},

issn = {2045-2322},

year  = {2019},

date = {2019-04-01},

journal = {Scientific reports},

volume = {9},

number = {1},

pages = {5695},

abstract = {Skp2 is a crucial component of SCF(Skp2) E3 ubiquitin ligase and is often overexpressed in various types of cancer, including prostate cancer (PCa). The epithelial-to-mesenchymal transition (EMT) is involved in PCa progression. The acquisition of a mesenchymal phenotype that results in a cancer stem cell (CSC) phenotype in PCa was described. Therefore, we aimed to investigate the expression and localization of Skp2 in clinical samples from patients with PCa, the association of Skp2 with EMT status, and the role of Skp2 in prostate CSC. We found that nuclear expression of Skp2 was increased in patients with PCa compared to those with benign hyperplasia, and correlated with high Gleason score in PCa patients. Increased Skp2 expression was observed in PCa cell lines with mesenchymal and CSC-like phenotype compared to their epithelial counterparts. Conversely, the CSC-like phenotype was diminished in cells in which SKP2 expression was silenced. Furthermore, we observed that Skp2 downregulation led to the decrease in subpopulation of CD44(+)CD24(-) cancer stem-like cells. Finally, we showed that high expression levels of both CD24 and CD44 were associated with favorable recurrence-free survival for PCa patients. This study uncovered the Skp2-mediated CSC-like phenotype with oncogenic functions in PCa.},

note = {Place: England},

keywords = {*Epithelial-Mesenchymal Transition, *Gene Expression Regulation, Animals, CD24 Antigen/genetics, Cell Line, Humans, Hyaluronan Receptors/genetics, Male, Mice, Neoplasm Grading, Neoplastic, Neoplastic Stem Cells/metabolism/*physiology, Nude, PC-3 Cells, Prostatic Neoplasms/*genetics/metabolism/physiopathology, S-Phase Kinase-Associated Proteins/*genetics, Tumor, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}

@article{remsik_trop-2_2018,

title = {Trop-2 plasticity is controlled by epithelial-to-mesenchymal transition.},

author = {Ján Remšík and Lucia Binó and Zuzana Kahounová and Gvantsa Kharaishvili and Šárka Šimecková and Radek Fedr and Tereza Kucírková and Sára Lenárt and Ximena Maria Muresan and Eva Slabáková and Lucia Knopfová and Jan Bouchal and Milan Král and Petr Beneš and Karel Soucek},

doi = {10.1093/carcin/bgy095},

issn = {1460-2180 0143-3334},

year  = {2018},

date = {2018-12-01},

journal = {Carcinogenesis},

volume = {39},

number = {11},

pages = {1411–1418},

abstract = {The cell surface glycoprotein Trop-2 is commonly overexpressed in carcinomas and represents an exceptional antigen for targeted therapy. Here, we provide evidence that surface Trop-2 expression is functionally connected with an epithelial phenotype in breast and prostate cell lines and in patient tumor samples. We further show that Trop-2 expression is suppressed epigenetically or through the action of epithelial-to-mesenchymal transition transcription factors and that deregulation of Trop-2 expression is linked with cancer progression and poor patient prognosis. Moreover, our data suggest that the cancer plasticity-driven intratumoral heterogeneity in Trop-2 expression may significantly contribute to response and resistance to therapies targeting Trop-2-expressing cells.},

note = {Place: England},

keywords = {Animals, Antigens, Breast Neoplasms/mortality/*pathology, Cadherins/biosynthesis, Carcinoma/*pathology, CD/biosynthesis, Cell Adhesion Molecules/genetics/*metabolism, Cell Line, Disease Progression, DNA Methylation/genetics, Epithelial Cells/*metabolism, Epithelial-Mesenchymal Transition/physiology, Female, Humans, Inbred BALB C, Male, Mice, Neoplasm/genetics/*metabolism, Prostatic Neoplasms/mortality/*pathology, Tumor, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}

@article{paculova_brca1_2017,

title = {BRCA1 or CDK12 loss sensitizes cells to CHK1 inhibitors.},

author = {Hana Paculová and Juraj Kramara and Šárka Šimečková and Radek Fedr and Karel Souček and Ondřej Hylse and Kamil Paruch and Marek Svoboda and Martin Mistrík and Jiří Kohoutek},

doi = {10.1177/1010428317727479},

issn = {1423-0380 1010-4283},

year  = {2017},

date = {2017-10-01},

journal = {Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine},

volume = {39},

number = {10},

pages = {1010428317727479},

abstract = {A broad spectrum of tumors develop resistance to classic chemotherapy, necessitating the discovery of new therapies. One successful strategy exploits the synthetic lethality between poly(ADP-ribose) polymerase 1/2 proteins and DNA damage response genes, including BRCA1, a factor involved in homologous recombination-mediated DNA repair, and CDK12, a transcriptional kinase known to regulate the expression of DDR genes. CHK1 inhibitors have been shown to enhance the anti-cancer effect of DNA-damaging compounds. Since loss of BRCA1 increases replication stress and leads to DNA damage, we tested a hypothesis that CDK12- or BRCA1-depleted cells rely extensively on S-phase-related CHK1 functions for survival. The silencing of BRCA1 or CDK12 sensitized tumor cells to CHK1 inhibitors in vitro and in vivo. BRCA1 downregulation combined with CHK1 inhibition induced excessive amounts of DNA damage, resulting in an inability to complete the S-phase. Therefore, we suggest CHK1 inhibition as a strategy for targeting BRCA1- or CDK12-deficient tumors.},

note = {Place: Netherlands},

keywords = {Animals, BRCA1, BRCA1 Protein/antagonists & inhibitors/*genetics, CDK12, Checkpoint Kinase 1/*genetics, CHK1 inhibitor, Colorectal Neoplasms/drug therapy/*genetics/pathology, Cyclin-Dependent Kinases/antagonists & inhibitors/*genetics, DNA damage response, DNA Damage/drug effects, Drug resistance, Gene Expression Regulation, Gene Silencing, HCT116 Cells, Humans, Mice, Neoplasm/genetics, Neoplastic/drug effects, Poly (ADP-Ribose) Polymerase-1/genetics, Pyrazoles/administration & dosage, Pyrimidines/administration & dosage, Transcription, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}

@article{samadder_synthesis_2017,

title = {Synthesis and Profiling of a Novel Potent Selective Inhibitor of CHK1 Kinase Possessing Unusual N-trifluoromethylpyrazole Pharmacophore Resistant to Metabolic N-dealkylation.},

author = {Pounami Samadder and Tereza Suchánková and Ondřej Hylse and Prashant Khirsariya and Fedor Nikulenkov and Stanislav Drápela and Nicol Straková and Petr Vaňhara and Kateřina Vašíčková and Hana Kolářová and Lucia Binó and Miroslava Bittová and Petra Ovesná and Peter Kollár and Radek Fedr and Milan Ešner and Josef Jaroš and Aleš Hampl and Lumír Krejčí and Kamil Paruch and Karel Souček},

doi = {10.1158/1535-7163.MCT-17-0018},

issn = {1538-8514 1535-7163},

year  = {2017},

date = {2017-09-01},

journal = {Molecular cancer therapeutics},

volume = {16},

number = {9},

pages = {1831–1842},

abstract = {Checkpoint-mediated dependency of tumor cells can be deployed to selectively kill them without substantial toxicity to normal cells. Specifically, loss of CHK1, a serine threonine kinase involved in the surveillance of the G(2)-M checkpoint in the presence of replication stress inflicted by DNA-damaging drugs, has been reported to dramatically influence the viability of tumor cells. CHK1's pivotal role in maintaining genomic stability offers attractive opportunity for increasing the selectivity, effectivity, and reduced toxicity of chemotherapy. Some recently identified CHK1 inhibitors entered clinical trials in combination with DNA antimetabolites. Herein, we report synthesis and profiling of MU380, a nontrivial analogue of clinically profiled compound SCH900776 possessing the highly unusual N-trifluoromethylpyrazole motif, which was envisioned not to undergo metabolic oxidative dealkylation and thereby provide greater robustness to the compound. MU380 is a selective and potent inhibitor of CHK1 which sensitizes a variety of tumor cell lines to hydroxyurea or gemcitabine up to 10 times. MU380 shows extended inhibitory effects in cells, and unlike SCH900776, does not undergo in vivo N-dealkylation to the significantly less selective metabolite. Compared with SCH900776, MU380 in combination with GEM causes higher accumulation of DNA damage in tumor cells and subsequent enhanced cell death, and is more efficacious in the A2780 xenograft mouse model. Overall, MU380 represents a novel state-of-the-art CHK1 inhibitor with high potency, selectivity, and improved metabolic robustness to oxidative N-dealkylation. Mol Cancer Ther; 16(9); 1831-42. ©2017 AACR.},

note = {Place: United States},

keywords = {Animal, Animals, Antineoplastic Agents/*chemical synthesis/*pharmacology, Apoptosis/drug effects, Biomarkers, Cell Cycle Checkpoints/drug effects, Cell Cycle/drug effects, Cell Line, Checkpoint Kinase 1/*antagonists & inhibitors, Dealkylation/drug effects, Disease Models, Dose-Response Relationship, Drug, Drug resistance, Humans, Methylation, Mice, Molecular Structure, Neoplasm/*drug effects, Protein Kinase Inhibitors/*chemical synthesis/*pharmacology, Pyrazoles/pharmacology, Pyrimidines/pharmacology, Tumor, Xenograft Model Antitumor Assays},

pubstate = {published},

tppubtype = {article}

}