During the preclinical development of small molecule inhibitors, compounds or compound libraries are typically first screened using purified target enzymes in vitro to select candidates with high potency. In the later stages of the development, however, functional cell-based assays may provide biologically more relevant data. In this chapter, we describe a detailed protocol for determining the potency of inhibitors targeting human histone deacetylase 6 in complex cellular environments. Cells are first treated with a dilution series of tested compounds, cell lysates separated by SDS-PAGE, and electrotransferred to a blotting membrane. The inhibitor potency is then determined indirectly by quantifying the levels of acetylated tubulin as a surrogate readout.

• MeSH
• acetylace MeSH
• histondeacetylasa 6 metabolismus   MeSH
• inhibitory histondeacetylas * farmakologie   MeSH
• lidé MeSH
• tubulin * metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

In-cell profiling enables the evaluation of receptor tyrosine activity in a complex environment of regulatory networks that affect signal initiation, propagation and feedback. We used FGF-receptor signaling to identifyEGR1as a locus that strongly responds to the activation of a majority of the recognized protein kinase oncogenes, including 30 receptor tyrosine kinases and 154 of their disease-associated mutants. TheEGR1promoter was engineered to enhancetrans-activation capacity and optimized for simple screening assays with luciferase or fluorescent reporters. The efficacy of the developed, fully synthetic reporters was demonstrated by the identification of novel targets for two clinically used tyrosine kinase inhibitors, nilotinib and osimertinib. A universal reporter system for in-cell protein kinase profiling will facilitate repurposing of existing anti-cancer drugs and identification of novel inhibitors in high-throughput screening studies.

• MeSH
• buněčné linie MeSH
• cytologické techniky metody   MeSH
• intravitální mikroskopie MeSH
• lidé MeSH
• myši MeSH
• onkogenní proteiny analýza   MeSH
• optické zobrazování MeSH
• proteinkinasy analýza   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Activating mutations in the fibroblast growth factor receptor 3 (FGFR3) cause the most common genetic form of human dwarfism, achondroplasia (ACH). Small chemical inhibitors of FGFR tyrosine kinase activity are considered to be viable option for treating ACH, but little experimental evidence supports this claim. We evaluated five FGFR tyrosine kinase inhibitors (TKIs) (SU5402, PD173074, AZD1480, AZD4547 and BGJ398) for their activity against FGFR signaling in chondrocytes. All five TKIs strongly inhibited FGFR activation in cultured chondrocytes and limb rudiment cultures, completely relieving FGFR-mediated inhibition of chondrocyte proliferation and maturation. In contrast, TKI treatment of newborn mice did not improve skeletal growth and had lethal toxic effects on the liver, lungs and kidneys. In cell-free kinase assays as well as in vitro and in vivo cell assays, none of the tested TKIs demonstrated selectivity for FGFR3 over three other FGFR tyrosine kinases. In addition, the TKIs exhibited significant off-target activity when screened against a panel of 14 unrelated tyrosine kinases. This was most extensive in SU5402 and AZD1480, which inhibited DDR2, IGF1R, FLT3, TRKA, FLT4, ABL and JAK3 with efficiencies similar to or greater than those for FGFR. Low target specificity and toxicity of FGFR TKIs thus compromise their use for treatment of ACH. Conceptually, different avenues of therapeutic FGFR3 targeting should be investigated.

• MeSH
• achondroplazie farmakoterapie   MeSH
• benzamidy farmakologie   MeSH
• chondrocyty metabolismus   MeSH
• chrupavka účinky léků   metabolismus   MeSH
• fenylmočovinové sloučeniny farmakologie   MeSH
• katalýza účinky léků   MeSH
• kultivované buňky MeSH
• kuřecí embryo MeSH
• lidé MeSH
• myši MeSH
• piperaziny farmakologie   MeSH
• pyrazoly farmakologie   MeSH
• pyrimidiny farmakologie   MeSH
• pyrroly farmakologie   MeSH
• receptory fibroblastových růstových faktorů antagonisté a inhibitory   MeSH
• signální transdukce účinky léků   MeSH
• syndrom MeSH
• tyrosinkinasové receptory antagonisté a inhibitory   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The short rib polydactyly syndromes (SRPS) are a group of recessively inherited, perinatal-lethal skeletal disorders primarily characterized by short ribs, shortened long bones, varying types of polydactyly and concomitant visceral abnormalities. Mutations in several genes affecting cilia function cause SRPS, revealing a role for cilia function in skeletal development. To identify additional SRPS genes and discover novel ciliary molecules required for normal skeletogenesis, we performed exome sequencing in a cohort of patients and identified homozygosity for a missense mutation, p.E80K, in Intestinal Cell Kinase, ICK, in one SRPS family. The p.E80K mutation abolished serine/threonine kinase activity, resulting in altered ICK subcellular and ciliary localization, increased cilia length, aberrant cartilage growth plate structure, defective Hedgehog and altered ERK signalling. These data identify ICK as an SRPS-associated gene and reveal that abnormalities in signalling pathways contribute to defective skeletogenesis.

• MeSH
• cilie genetika   patologie   MeSH
• exom genetika   MeSH
• kojenec MeSH
• kostra abnormality   růst a vývoj   MeSH
• lidé MeSH
• MAP kinasový signální systém MeSH
• mnohočetné abnormality genetika   patofyziologie   MeSH
• protein-serin-threoninkinasy genetika   MeSH
• proteiny hedgehog genetika   MeSH
• rodokmen MeSH
• sekvenční analýza DNA MeSH
• signální transdukce MeSH
• syndrom krátkého žebra a polydaktylie genetika   patologie   MeSH
• těhotenství MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Despite recent advances in targeted therapeutics, administration of 5-fluorouracil (5-FU) remains a common clinical strategy for post-surgical treatment of solid tumors. Although it has been proposed that RNA metabolism is disturbed by 5-FU treatment, the key cytotoxic response is believed to be enzymatic inhibition of thymidylate synthase resulting in nucleotide pool disproportions. An operating p53 tumor suppressor signaling network is in many cases essential for the efficiency of chemotherapy, and malfunctions within this system remain a clinical obstacle. Since the fate of chemotherapy-insensitive tumor cells is rarely described, we performed a comparative analysis of 5-FU toxicity in p53-deficient cells and conclude that p53 acts as a facilitator rather than a gatekeeper of cell death. Although p53 can act as a regulator of several cellular stress responses, no rerouting of cell death mode was observed in absence of the tumor suppressor. Thus, the final death outcome of 5-FU-treated p53-/- cells is demonstrated to be caspase-dependent, but due to a slow pace, accumulation of mitochondrial reactive oxygen species contributes to necrotic characteristics. The oligomerization status of the p53 target gene DR5 is determined as a significant limiting factor for the initiation of caspase activity in an intracellular TRAIL-dependent manner. Using several experimental approaches, we further conclude that RNA-rather than DNA-related stress follows by caspase activation irrespectively of p53 status. A distinct 5-FU-induced stress mechanism is thereby functionally connected to a successive and discrete cell death signaling pathway. Finally, we provide evidence that silencing of PARP-1 function may be an approach to specifically target p53-deficient cells in 5-FU combinatorial treatment strategies. Together, our results disclose details of impaired cell death signaling engaged as a consequence of 5-FU chemotherapy. Obtained data will contribute to the comprehension of factors restraining 5-FU efficiency, and by excluding DNA as the main stress target in some cell types they propose alternatives to currently used and suggested synergistic treatment regimens.

• MeSH
• antimetabolity antitumorózní farmakologie   MeSH
• apoptóza účinky léků   MeSH
• fluorescenční protilátková technika MeSH
• fluorouracil farmakologie   MeSH
• imunoblotting MeSH
• imunoprecipitace MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• polymerázová řetězová reakce MeSH
• protein TRAIL metabolismus   MeSH
• RNA účinky léků   MeSH
• signální transdukce účinky léků   fyziologie   MeSH
• transdukce genetická MeSH
• transmisní elektronová mikroskopie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Aberrant fibroblast growth factor (FGF) signaling disturbs chondrocyte differentiation in skeletal dysplasia, but the mechanisms underlying this process remain unclear. Recently, FGF was found to activate canonical WNT/β-catenin pathway in chondrocytes via Erk MAP kinase-mediated phosphorylation of WNT co-receptor Lrp6. Here, we explore the cellular consequences of such a signaling interaction. WNT enhanced the FGF-mediated suppression of chondrocyte differentiation in mouse limb bud micromass and limb organ cultures, leading to inhibition of cartilage nodule formation in micromass cultures, and suppression of growth in cultured limbs. Simultaneous activation of the FGF and WNT/β-catenin pathways resulted in loss of chondrocyte extracellular matrix, expression of genes typical for mineralized tissues and alteration of cellular shape. WNT enhanced the FGF-mediated downregulation of chondrocyte proteoglycan and collagen extracellular matrix via inhibition of matrix synthesis and induction of proteinases involved in matrix degradation. Expression of genes regulating RhoA GTPase pathway was induced by FGF in cooperation with WNT, and inhibition of the RhoA signaling rescued the FGF/WNT-mediated changes in chondrocyte cellular shape. Our results suggest that aberrant FGF signaling cooperates with WNT/β-catenin in suppression of chondrocyte differentiation.

• MeSH
• beta-katenin genetika   metabolismus   MeSH
• biologické modely MeSH
• buněčná diferenciace účinky léků   genetika   MeSH
• chondrocyty účinky léků   metabolismus   MeSH
• chrupavka cytologie   účinky léků   metabolismus   MeSH
• fibroblastové růstové faktory farmakologie   MeSH
• fibroblastový růstový faktor 2 farmakologie   MeSH
• HEK293 buňky MeSH
• končetinové pupeny účinky léků   embryologie   metabolismus   MeSH
• konfokální mikroskopie MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• LDL receptor related protein 6 genetika   metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein Wnt3A farmakologie   MeSH
• proteiny Wnt genetika   metabolismus   farmakologie   MeSH
• receptory fibroblastových růstových faktorů genetika   metabolismus   MeSH
• signální transdukce účinky léků   genetika   MeSH
• synergismus léků MeSH
• transkriptom účinky léků   genetika   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid present in fish oil, may exert cytotoxic and/or cytostatic effects on colon cancer cells when applied individually or in combination with some anticancer drugs. Here we demonstrate a selective ability of subtoxic doses of DHA to enhance antiproliferative and apoptotic effects of clinically useful cytokine TRAIL (tumor necrosis factor-related apoptosis inducing ligand) in cancer but not normal human colon cells. DHA-mediated stimulation of TRAIL-induced apoptosis was associated with extensive engagement of mitochondrial pathway (Bax/Bak activation, drop of mitochondrial membrane potential, cytochrome c release), activation of endoplasmic reticulum stress response (CHOP upregulation, changes in PERK level), decrease of cellular inhibitor of apoptosis protein (XIAP, cIAP1) levels and significant changes in sphingolipid metabolism (intracellular levels of ceramides, hexosyl ceramides, sphingomyelines, sphingosines; HPLC/MS/MS). Interestingly, we found significant differences in representation of various classes of ceramides (especially C16:0, C24:1) between the cancer and normal colon cells treated with DHA and TRAIL, and suggested their potential role in the regulation of the cell response to the drug combination. These study outcomes highlight the potential of DHA for a new combination therapy with TRAIL for selective elimination of colon cancer cells via simultaneous targeting of multiple steps in apoptotic pathways.

• MeSH
• adenokarcinom genetika   metabolismus   patologie   MeSH
• apoptóza účinky léků   genetika   MeSH
• cytochromy c sekrece   MeSH
• inhibitory apoptózy MeSH
• kinasa eIF-2 genetika   metabolismus   MeSH
• kyseliny dokosahexaenové farmakologie   MeSH
• lidé MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádory tračníku genetika   metabolismus   patologie   MeSH
• protein Bak genetika   metabolismus   MeSH
• protein TRAIL farmakologie   MeSH
• protein X asociovaný s bcl-2 genetika   metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• sfingolipidy chemie   klasifikace   metabolismus   MeSH
• signální transdukce MeSH
• stres endoplazmatického retikula účinky léků   MeSH
• synergismus léků MeSH
• transkripční faktor CHOP genetika   metabolismus   MeSH
• X-vázaný inhibitor apoptózy genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In search for novel strategies in colon cancer treatment, we investigated the unique ability of platinum(IV) complex LA-12 to efficiently enhance the killing effects of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), and compared it with the sensitizing action of cisplatin. We provide the first evidence that LA-12 primes human colon cancer cells for TRAIL-induced cytotoxicity by p53-independent activation of the mitochondrial apoptotic pathway. The cooperative action of LA-12 and TRAIL was associated with stimulation of Bax/Bak activation, drop of mitochondrial membrane potential, caspase-9 activation, and a shift of the balance among Bcl-2 family proteins in favor of the pro-apoptotic members. In contrast to cisplatin, LA-12 was a potent inducer of ERK-mediated Noxa and BimL protein upregulation, and more effectively enhanced TRAIL-induced apoptosis in the absence of Bax. The cooperative action of LA-12 and TRAIL was augmented following the siRNA-mediated silencing of Mcl-1 in both Bax proficient/deficient cells. We newly demonstrated that LA-12 induced ERK-mediated c-Myc upregulation, and proved that c-Myc silencing inhibited the mitochondrial activation and apoptosis in colon cancer cells treated with LA-12 and TRAIL. The LA-12-mediated sensitization to TRAIL-induced apoptosis was demonstrated in several colon cancer cell lines, further underscoring the general relevance of our findings. The selective action of LA-12 was documented by preferential priming of cancer but not normal colon cancer cells to TRAIL killing effects. Our work highlights the promising potential of LA-12 over cisplatin to enhance the colon cancer cell sensitivity to TRAIL-induced apoptosis, and provides new mechanistic insights into their cooperative action.

• MeSH
• amantadin analogy a deriváty   farmakologie   MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza účinky léků   genetika   MeSH
• cisplatina farmakologie   MeSH
• geny p53 MeSH
• HCT116 buňky účinky léků   MeSH
• lidé MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• nádorové buňky kultivované MeSH
• nádory tračníku farmakoterapie   metabolismus   patologie   MeSH
• organoplatinové sloučeniny farmakologie   MeSH
• protein Bak metabolismus   MeSH
• protein TRAIL metabolismus   farmakologie   MeSH
• protein X asociovaný s bcl-2 genetika   metabolismus   MeSH
• protoonkogenní proteiny c-bcl-2 metabolismus   MeSH
• protoonkogenní proteiny c-myc genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tumour necrosis factor (TNF) related apoptosis inducing ligand (TRAIL), a membrane-bound ligand from the TNF family, has attracted significant attention due to its rather specific and effective ability to induce apoptotic death in various types of cancer cells via binding to and activating its pro-apoptotic death receptors. However, a significant number of primary cancer cells often develop resistance to TRAIL treatment, and the signalling platform behind this phenomenon is not fully understood. Upon blocking endosomal acidification by the vacuolar ATPase (V-ATPase) inhibitors bafilomycin A1 (BafA1) or concanamycin A, we observed a significantly reduced initial sensitivity of several, mainly colorectal, tumour cell lines to TRAIL-induced apoptosis. In cells pretreated with these inhibitors, the TRAIL-induced processing of caspase-8 and the aggregation and trafficking of the TRAIL receptor complexes were temporarily attenuated. Nuclear factor κB or mitogen activated protein/stress kinase signalling from the activated TRAIL receptors remained unchanged, and neither possible lysosomal permeabilization nor acid sphingomyelinase was involved in this process. The cell surface expression of TRAIL receptors and their TRAIL-induced internalization were not affected by V-ATPase inhibitors. The inhibitory effect of BafA1, however, was blunted by knockdown of the caspase-8 inhibitor cFLIP. Altogether, the data obtained provide the first evidence that endosomal acidification could represent an important regulatory node in the proximal part of TRAIL-induced pro-apoptotic signalling.

• MeSH
• aktivace enzymů MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza MeSH
• down regulace MeSH
• endozomy metabolismus   MeSH
• FLIP (buněčný) metabolismus   MeSH
• kaspasa 8 metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• makrolidy farmakologie   MeSH
• nádorové buněčné linie MeSH
• protein TRAIL farmakologie   MeSH
• sfingolipidy fyziologie   MeSH
• sfingomyelinfosfodiesterasa metabolismus   MeSH
• signální adaptorové proteiny receptorové domény smrti metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• TRAIL receptory metabolismus   MeSH
• transport proteinů MeSH
• vakuolární protonové ATPasy antagonisté a inhibitory   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH