Gene inactivation of the cyclin-dependent kinase inhibitors p16INK4a, p15INK4b and p21WAF is frequently mediated by promoter gene methylation, whereas histone deacetylases (HDACs) control gene expression through their ability to deacetylate proteins. The effect of suberohydroxamic acid (SBHA) and 5-Aza-2'-deoxycytidine (Decitabine) (DAC) treatments on the transcription of CDKN2A, CDKN2B and CDKN1A genes, and their effects on molecular biological behavior were examined in two myeloma cell lines, RPMI8226 and U266, which differ in p53-functionality and IL-6 expression. In both tested myeloma cell lines, a non-methylated state of the CDKN2B gene promoter region was detected with normal gene expression, and the same level of p15INK4b protein was detected by immunocytochemical staining. Furthermore, in myeloma cells treated with SBHA and DAC alone, the expression of both p15INK4b and p21WAF was significantly upregulated in RPMI8226 cells (p53-functional, without IL-6 expression), whereas in the U266 cell line (p53 deleted, expressing IL-6) only p21WAF expression was significantly increased. Moreover, the analysis revealed that treatment with DAC induced DNMT3B enhancement in U266 cells. In conclusion, in myeloma cells with IL-6 expression, significantly increased DNMT3B expression indicated the tumorigenic consequences of 5-Aza-2'deoxycytidine treatment, which requires careful use in diseases involving epigenetic dysregulation, such as multiple myeloma (MM).

• MeSH
• decitabin * farmakologie   MeSH
• DNA-(cytosin-5-)methyltransferasa * genetika   metabolismus   MeSH
• epigeneze genetická * MeSH
• inhibitor p15 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• inhibitor p16 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• interleukin-6 genetika   metabolismus   MeSH
• lidé MeSH
• metylace DNA MeSH
• mnohočetný myelom * genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• proteiny buněčného cyklu genetika   metabolismus   MeSH
• umlčování genů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Despite several approved therapeutic modalities, multiple myeloma (MM) remains an incurable blood malignancy and only a small fraction of patients achieves prolonged disease control. The common anti-MM treatment targets proteasome with specific inhibitors (PI). The resulting interference with protein degradation is particularly toxic to MM cells as they typically accumulate large amounts of toxic proteins. However, MM cells often acquire resistance to PIs through aberrant expression or mutations of proteasome subunits such as PSMB5, resulting in disease recurrence and further treatment failure. Here we propose CuET-a proteasome-like inhibitor agent that is spontaneously formed in-vivo and in-vitro from the approved alcohol-abuse drug disulfiram (DSF), as a readily available treatment effective against diverse resistant forms of MM. We show that CuET efficiently kills also resistant MM cells adapted to proliferate under exposure to common anti-myeloma drugs such as bortezomib and carfilzomib used as the first-line therapy, as well as to other experimental drugs targeting protein degradation upstream of the proteasome. Furthermore, CuET can overcome also the adaptation mechanism based on reduced proteasome load, another clinically relevant form of treatment resistance. Data obtained from experimental treatment-resistant cellular models of human MM are further corroborated using rather unique advanced cytotoxicity experiments on myeloma and normal blood cells obtained from fresh patient biopsies including newly diagnosed as well as relapsed and treatment-resistant MM. Overall our findings suggest that disulfiram repurposing particularly if combined with copper supplementation may offer a promising and readily available treatment option for patients suffering from relapsed and/or therapy-resistant multiple myeloma.

• MeSH
• antitumorózní látky * farmakologie   terapeutické užití   MeSH
• bortezomib farmakologie   terapeutické užití   MeSH
• chemorezistence MeSH
• disulfiram farmakologie   MeSH
• inhibitory proteasomu farmakologie   terapeutické užití   MeSH
• lidé MeSH
• lokální recidiva nádoru farmakoterapie   MeSH
• mnohočetný myelom * patologie   MeSH
• nádorové buněčné linie MeSH
• přehodnocení terapeutických indikací léčivého přípravku MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Molecular pathophysiology of Diamond-Blackfan anemia (DBA) involves disrupted erythroid-lineage proliferation, differentiation and apoptosis; with the activation of p53 considered as a key component. Recently, oxidative stress was proposed to play an important role in DBA pathophysiology as well. CRISPR/Cas9-created Rpl5- and Rps19-deficient murine erythroleukemia (MEL) cells and DBA patients' samples were used to evaluate proinflammatory cytokines, oxidative stress, DNA damage and DNA damage response. We demonstrated that the antioxidant defense capacity of Rp-mutant cells is insufficient to meet the greater reactive oxygen species (ROS) production which leads to oxidative DNA damage, cellular senescence and activation of DNA damage response signaling in the developing erythroblasts and altered characteristics of mature erythrocytes. We also showed that the disturbed balance between ROS formation and antioxidant defense is accompanied by the upregulation of proinflammatory cytokines. Finally, the alterations detected in the membrane of DBA erythrocytes may cause their enhanced recognition and destruction by reticuloendothelial macrophages, especially during infections. We propose that the extent of oxidative stress and the ability to activate antioxidant defense systems may contribute to high heterogeneity of clinical symptoms and response to therapy observed in DBA patients.

• MeSH
• Diamondova-Blackfanova anemie imunologie   metabolismus   patologie   MeSH
• dítě MeSH
• dospělí MeSH
• erytrocyty metabolismus   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mediátory zánětu metabolismus   MeSH
• mladý dospělý MeSH
• myši MeSH
• následné studie MeSH
• oxidační stres * MeSH
• poškození DNA * MeSH
• prognóza MeSH
• studie případů a kontrol MeSH
• zánět imunologie   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND/AIM: Multiple myeloma is a highly heterogeneous disease of clonal plasma cells. Histone deacetylase (HDAC) inhibitors are promising anticancer drugs but their precise mechanisms of actions are not well understood. MATERIALS AND METHODS: Cell-cycle regulation and pro-apoptotic effects of two histone deacetylase inhibitors, suberohydroxamic acid (SAHA) and suberoylanilide hydroxamic acid (SBHA), were analyzed in multiple myeloma cell lines RPMI8226 and U266 with differing TP53 status using gene-expression analysis. RESULTS: Enhanced expression of cyclin-dependent kinase inhibitor 1A (CDKN1A/p21WAF/CIP1) detected in the TP53-deleted U266 cell line after SAHA treatment indicates the P53-independent mode of transcriptional activation of CDKN1A gene. In contrast, CDKN1A gene expression was significantly increased by both SBHA and SAHA treatment of TP53-mutated RPMI8226 cells. CONCLUSION: SAHA appears to be a potentially effective pro-apoptotic and anticancer drug with universal application in the treatment of heterogeneous populations of multiple myeloma cells.

• MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza účinky léků   MeSH
• inhibitor p21 cyklin-dependentní kinasy antagonisté a inhibitory   genetika   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• kontrolní body buněčného cyklu účinky léků   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• mnohočetný myelom farmakoterapie   genetika   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

Inflammatory and oncogenic signaling, both known to challenge genome stability, are key drivers of BCR-ABL-positive chronic myeloid leukemia (CML) and JAK2 V617F-positive chronic myeloproliferative neoplasms (MPNs). Despite similarities in chronic inflammation and oncogene signaling, major differences in disease course exist. Although BCR-ABL has robust transformation potential, JAK2 V617F-positive polycythemia vera (PV) is characterized by a long and stable latent phase. These differences reflect increased genomic instability of BCR-ABL-positive CML, compared to genome-stable PV with rare cytogenetic abnormalities. Recent studies have implicated BCR-ABL in the development of a "mutator" phenotype fueled by high oxidative damage, deficiencies of DNA repair, and defective ATR-Chk1-dependent genome surveillance, providing a fertile ground for variants compromising the ATM-Chk2-p53 axis protecting chronic phase CML from blast crisis. Conversely, PV cells possess multiple JAK2 V617F-dependent protective mechanisms, which ameliorate replication stress, inflammation-mediated oxidative stress and stress-activated protein kinase signaling, all through up-regulation of RECQL5 helicase, reactive oxygen species buffering system, and DUSP1 actions. These attenuators of genome instability then protect myeloproliferative progenitors from DNA damage and create a barrier preventing cellular stress-associated myelofibrosis. Therefore, a better understanding of BCR-ABL and JAK2 V617F roles in the DNA damage response and disease pathophysiology can help to identify potential dependencies exploitable for therapeutic interventions.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: Castration-resistant prostate cancer (PCa) represents a serious health challenge. Based on mechanistically-supported rationale we explored new therapeutic options based on clinically available drugs with anticancer effects, including inhibitors of PARP1 enzyme (PARPi), and histone deacetylases (vorinostat), respectively, and disulfiram (DSF, known as alcohol-abuse drug Antabuse) and its copper-chelating metabolite CuET that inhibit protein turnover. METHODS: Drugs and their combination with ionizing radiation (IR) were tested in various cytotoxicity assays in three human PCa cell lines including radio-resistant stem-cell like derived cells. Mechanistically, DNA damage repair, heat shock and unfolded protein response (UPR) pathways were assessed by immunofluorescence and immunoblotting. RESULTS: We observed enhanced sensitivity to PARPi/IR in PC3 cells consistent with lower homologous recombination (HR) repair. Vorinostat sensitized DU145 cells to PARPi/IR and decreased mutant p53. Vorinostat also impaired HR-mediated DNA repair, as determined by Rad51 foci formation and downregulation of TOPBP1 protein, and overcame radio-resistance of stem-cell like DU145-derived cells. All PCa models responded well to CuET or DSF combined with copper. We demonstrated that DSF interacts with copper in the culture media and forms adequate levels of CuET indicating that DSF/copper and CuET may be considered as comparable treatments. Both DSF/copper and CuET evoked hallmarks of UPR in PCa cells, documented by upregulation of ATF4, CHOP and phospho-eIF2α, with ensuing heat shock response encompassing activation of HSF1 and HSP70. Further enhancing the cytotoxicity of CuET, combination with an inhibitor of the anti-apoptotic protein survivin (YM155, currently undergoing clinical trials) promoted the UPR-induced toxicity, yielding synergistic effects of CuET and YM155. CONCLUSIONS: We propose that targeting genotoxic and proteotoxic stress responses by combinations of available drugs could inspire innovative strategies to treat castration-resistant PCa.

• MeSH
• buňky PC-3 MeSH
• cílená molekulární terapie metody   MeSH
• disulfiram terapeutické užití   MeSH
• fosfohydroláza PTEN genetika   MeSH
• fyziologický stres účinky léků   genetika   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nádory prostaty farmakoterapie   MeSH
• oprava DNA účinky léků   MeSH
• PARP inhibitory terapeutické užití   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• rekombinační oprava DNA účinky léků   MeSH
• tolerance záření MeSH
• vorinostat terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Aldehyde dehydrogenase (ALDH) is a proposed biomarker and possible target to eradicate cancer stem cells. ALDH inhibition as a treatment approach is supported by anti-cancer effects of the alcohol-abuse drug disulfiram (DSF, Antabuse). Given that metabolic products of DSF, rather than DSF itself inhibit ALDH in vivo, and that DSF's anti-cancer activity is potentiated by copper led us to investigate the relevance of ALDH as the suggested molecular cancer-relevant target of DSF. Here we show that DSF does not directly inhibit ALDH activity in diverse human cell types, while DSF's in vivo metabolite, S-methyl-N,N-diethylthiocarbamate-sulfoxide inhibits ALDH activity yet does not impair cancer cell viability. Our data indicate that the anti-cancer activity of DSF does not involve ALDH inhibition, and rather reflects the impact of DSF's copper-containing metabolite (CuET), that forms spontaneously in vivo and in cell culture media, and kills cells through aggregation of NPL4, a subunit of the p97/VCP segregase. We also show that the CuET-mediated, rather than any ALDH-inhibitory activity of DSF underlies the preferential cytotoxicity of DSF towards BRCA1- and BRCA2-deficient cells. These findings provide evidence clarifying the confusing literature about the anti-cancer mechanism of DSF, a drug currently tested in clinical trials for repositioning in oncology.

• MeSH
• aldehyddehydrogenasa antagonisté a inhibitory   MeSH
• antitumorózní látky metabolismus   farmakologie   MeSH
• buňky A549 MeSH
• buňky K562 MeSH
• disulfiram metabolismus   farmakologie   MeSH
• inhibitory acetaldehyd dehydrogenasy metabolismus   farmakologie   MeSH
• jaderné proteiny metabolismus   MeSH
• kultivační média MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The advanced-stage colon cancer spreads from primary tumor site to distant organs where the colon-unassociated stromal population provides a favorable niche for the growth of tumor cells. The heterocellular interactions between colon cancer cells and colon-unassociated fibroblasts at distant metastatic sites are important, yet these cell-cell interactions for therapeutic strategies for metastatic colon cancer remain underestimated. Recent studies have shown the therapeutic potential of DNA-demethylating epi-drugs 5-azacytidine (AZA) and 5-aza-2'-deoxycytidine (DAC) for the treatment of solid tumors. While the effects of these epi-drugs alone or in combination with other anticancer therapies are well described, the influence of stromal cells and their secretome on cancer cell response to these agents remain elusive. In this study, we determined the effect of normal and senescent colon-unassociated fibroblasts and their conditioned medium on colorectal cancer (CRC) cell response to AZA and DAC using a cell-based DNA demethylation reporter system. Our data show that fibroblasts accelerate cell proliferation and differentially regulate the expression of DNA methylation-regulating enzymes, enhancing DAC-induced demethylation in CRC cells. In contrast, the conditioned medium from senescent fibroblasts that upregulated NF-κB activity altered deoxycytidine kinase levels in drug-untreated CRC cells and abrogated DAC effect on degradation of DNA methyltransferase 1. Similar to 2D cultures, senescent fibroblasts increased DNA demethylation of CRC cells in coculture spheroids, in addition to increasing the stemness of CRC cells. This study presents the first evidence of the effect of normal and senescent stromal cells and their conditioned medium on DNA demethylation by DAC. The data show an increased activity of DAC in high stromal cell cocultures and suggest the potential of the tumor-stroma ratio in predicting the outcome of DNA-demethylating epigenetic cancer therapy.

• Publikační typ
• časopisecké články MeSH

Cancer incidence is rising and this global challenge is further exacerbated by tumour resistance to available medicines. A promising approach to meet the need for improved cancer treatment is drug repurposing. Here we highlight the potential for repurposing disulfiram (also known by the trade name Antabuse), an old alcohol-aversion drug that has been shown to be effective against diverse cancer types in preclinical studies. Our nationwide epidemiological study reveals that patients who continuously used disulfiram have a lower risk of death from cancer compared to those who stopped using the drug at their diagnosis. Moreover, we identify the ditiocarb-copper complex as the metabolite of disulfiram that is responsible for its anti-cancer effects, and provide methods to detect preferential accumulation of the complex in tumours and candidate biomarkers to analyse its effect on cells and tissues. Finally, our functional and biophysical analyses reveal the molecular target of disulfiram's tumour-suppressing effects as NPL4, an adaptor of p97 (also known as VCP) segregase, which is essential for the turnover of proteins involved in multiple regulatory and stress-response pathways in cells.

• MeSH
• alkoholismus farmakoterapie   epidemiologie   MeSH
• antitumorózní látky * farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie MeSH
• disulfiram chemie   farmakologie   terapeutické užití   MeSH
• dospělí MeSH
• jaderné proteiny chemie   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• měď chemie   MeSH
• myši MeSH
• nádory farmakoterapie   metabolismus   mortalita   patologie   MeSH
• odvykací prostředky alkoholu * farmakologie   terapeutické užití   MeSH
• přehodnocení terapeutických indikací léčivého přípravku * MeSH
• proteinové agregáty MeSH
• proteolýza účinky léků   MeSH
• reakce na tepelný šok účinky léků   MeSH
• vazba proteinů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Dánsko epidemiologie   MeSH

Replication stress (RS) fuels genomic instability and cancer development and may contribute to aging, raising the need to identify factors involved in cellular responses to such stress. Here, we present a strategy for identification of factors affecting the maintenance of common fragile sites (CFSs), which are genomic loci that are particularly sensitive to RS and suffer from increased breakage and rearrangements in tumors. A DNA probe designed to match the high flexibility island sequence typical for the commonly expressed CFS (FRA16D) was used as specific DNA affinity bait. Proteins significantly enriched at the FRA16D fragment under normal and replication stress conditions were identified using stable isotope labeling of amino acids in cell culture-based quantitative mass spectrometry. The identified proteins interacting with the FRA16D fragment included some known CFS stabilizers, thereby validating this screening approach. Among the hits from our screen so far not implicated in CFS maintenance, we chose Xeroderma pigmentosum protein group C (XPC) for further characterization. XPC is a key factor in the DNA repair pathway known as global genomic nucleotide excision repair (GG-NER), a mechanism whose several components were enriched at the FRA16D fragment in our screen. Functional experiments revealed defective checkpoint signaling and escape of DNA replication intermediates into mitosis and the next generation of XPC-depleted cells exposed to RS. Overall, our results provide insights into an unexpected biological role of XPC in response to replication stress and document the power of proteomics-based screening strategies to elucidate mechanisms of pathophysiological significance.

• MeSH
• chromatografie afinitní MeSH
• DNA vazebné proteiny fyziologie   MeSH
• fragilní místa na chromozomu MeSH
• kontrolní body buněčného cyklu MeSH
• lidé MeSH
• oprava DNA fyziologie   MeSH
• proteomika metody   MeSH
• replikace DNA fyziologie   MeSH
• xeroderma pigmentosum MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH