In esophageal squamous cell carcinoma, genetic activation of NRF2 increases resistance to chemotherapy and radiotherapy, which results in a significantly worse prognosis for patients. Therefore NRF2-activated cancers create an urgent clinical need to identify new therapeutic options. In this context, we previously identified the geldanamycin family of HSP90 inhibitors, which includes 17DMAG, to be synthetic lethal with NRF2 activity. As the first-generation of geldanamycin-derivative drugs were withdrawn from clinical trials due to hepatotoxicity, we designed second-generation compounds with C19-substituted structures in order to inhibit glutathione conjugation-mediated hepatotoxicity. In this study, using a variety of in vitro and in vivo cancer models, we found that C19-substituted 17DMAG compounds maintain their enhanced toxicity profile and synthetic lethal interaction with NRF2-NQO1-activated cancer cells. Importantly, using a xenograft mouse tumor model, we found that C19-substituted 17DMAG displayed significant anticancer efficacy against NRF2-NQO1-activated cancer cells without causing hepatotoxicity. These results clearly demonstrate the improved clinical potential for this new class of HSP90 inhibitor anticancer drugs, and suggest that patients with NRF2-NQO1-activated esophageal carcinoma may benefit from this novel therapeutic approach.

• Klíčová slova
• C19-position substituted geldanamycin derivatives, ESCC, HSP90, NQO1, NRF2-NQO1-activated cancer,
• MeSH
• antitumorózní látky farmakologie   chemie   MeSH
• benzochinony * farmakologie   chemie   MeSH
• faktor 2 související s NF-E2 * metabolismus   genetika   MeSH
• lidé MeSH
• makrocyklické laktamy * farmakologie   chemie   terapeutické užití   MeSH
• myši nahé MeSH
• myši MeSH
• NAD(P)H dehydrogenasa (chinon) * metabolismus   genetika   MeSH
• nádorové buněčné linie MeSH
• nádory jícnu * farmakoterapie   metabolismus   genetika   MeSH
• proteiny tepelného šoku HSP90 antagonisté a inhibitory   metabolismus   MeSH
• skvamózní karcinom jícnu * farmakoterapie   genetika   metabolismus   MeSH
• xenogenní modely - testy antitumorózní aktivity * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• benzochinony * MeSH
• faktor 2 související s NF-E2 * MeSH
• geldanamycin MeSH Prohlížeč
• makrocyklické laktamy * MeSH
• NAD(P)H dehydrogenasa (chinon) * MeSH
• NFE2L2 protein, human MeSH Prohlížeč
• NQO1 protein, human MeSH Prohlížeč
• proteiny tepelného šoku HSP90 MeSH

In the complex network of cellular physiology, the maintenance of cellular proteostasis emerges as a critical factor for cell survival, particularly under stress conditions. This homeostasis is largely governed by a sophisticated network of molecular chaperones and co-chaperones, among which Bcl-2-associated athanogene 3 (BAG3), able to interact with the ATPase domain of Heat Shock Protein 70 (HSP70), plays a pivotal role. The BAG3-HSP70 functional module is not only essential for cellular homeostasis but is also involved in the pathogenesis of various diseases, including cancer, neurodegenerative disorders, and cardiac dysfunction, making it an attractive target for therapeutic intervention. Inspired by our continuous interest in the development of new chemical platforms able to interfere with BAG3 protein, herein we report the discovery of compound 16, the first-in-class BAG3/HSP70 dual modulator, obtained by combining the multicomponent Ugi reaction with the alkyne-azide Huisgen procedure in a sequential tandem reaction approach. Through a combination of biophysical analysis, biochemical assays, and cell-based studies, we elucidated the mechanism of action of this inhibitor and assessed its potential as a therapeutic agent. Hence, this study can open new avenues for the development of novel anticancer strategies that leverage the simultaneous disruption of multiple chaperone pathways.

• Klíčová slova
• Anticancer agent, BAG3, Dual modulator, HSP70, Ugi-Huisgen tandem approach,
• MeSH
• adaptorové proteiny signální transdukční * metabolismus   antagonisté a inhibitory   MeSH
• antitumorózní látky * farmakologie   chemie   chemická syntéza   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• molekulární chaperony metabolismus   antagonisté a inhibitory   chemie   MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• proliferace buněk účinky léků   MeSH
• proteiny regulující apoptózu * metabolismus   antagonisté a inhibitory   MeSH
• proteiny tepelného šoku HSP70 * antagonisté a inhibitory   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adaptorové proteiny signální transdukční * MeSH
• antitumorózní látky * MeSH
• BAG3 protein, human MeSH Prohlížeč
• molekulární chaperony MeSH
• proteiny regulující apoptózu * MeSH
• proteiny tepelného šoku HSP70 * MeSH

Pollen germination and pollen tube (PT) growth are extremely sensitive to high temperatures. During heat stress (HS), global translation shuts down and favors the maintenance of the essential cellular proteome for cell viability and protection against protein misfolding. Here, we demonstrate that under normal conditions, the Arabidopsis (Arabidopsis thaliana) eukaryotic translation initiation factor subunit eif3m1/eif3m2 double mutant exhibits poor pollen germination, loss of PT integrity and an increased rate of aborted seeds. Surprisingly, under HS at 37 °C, eif3m1 pollen germination outperformed wild-type Col-0, showing enhanced PT integrity. We established that the improved thermotolerance of the eif3m1 PT was due to increased expression of its putative paralog eIF3M2, which in turn upregulated Heat Shock protein 70 (HSP70) mRNA and protein levels. Indeed, eIF3M2 overexpression upregulated HSP70 expression, whereas eif3m2 knockdown showed reduced HSP70.1 promoter activity and increased in PT burst under HS conditions. Moreover, we show that eIF3M2 coimmunoprecipitates with HSP70 in PTs and directly interacts with cytoplasmic HSP70.1/2/4 and eIF4G in Nicotiana benthamiana pavement cells. Collectively, our data revealed that plants employ the eIF3M2-HSP70 module as a regulator of thermotolerance to maintain PT membrane integrity and improve fertilization and seed set adaptation under high temperatures.

• MeSH
• Arabidopsis * genetika   metabolismus   fyziologie   MeSH
• buněčná membrána metabolismus   MeSH
• eukaryotický iniciační faktor 3 metabolismus   genetika   MeSH
• klíčení genetika   MeSH
• proteiny huseníčku * metabolismus   genetika   MeSH
• proteiny tepelného šoku HSP70 * metabolismus   genetika   MeSH
• pylová láčka * růst a vývoj   genetika   metabolismus   MeSH
• reakce na tepelný šok * genetika   MeSH
• regulace genové exprese u rostlin MeSH
• upregulace genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• eukaryotický iniciační faktor 3 MeSH
• proteiny huseníčku * MeSH
• proteiny tepelného šoku HSP70 * MeSH

Protein folding is an extremely complicated process, which has been extensively tackled during the last decades. In vivo, a certain molecular machinery is responsible for assisting the correct folding of proteins and maintaining protein homeostasis: the members of this machinery are the heat shock proteins (HSPs), which belong among molecular chaperones. Mutations in HSPs are associated with several inherited diseases, and members of this group were also proved to be involved in neurodegenerative pathologies (e.g., Alzheimer and Parkinson diseases), cancer, viral infections, and antibiotic resistance of bacteria. Therefore, it is critical to understand the principles of HSP functioning and their exact role in human physiology and pathology. This review attempts to briefly describe the main chaperone families and the interplay between individual chaperones, as well as their general and specific functions in the context of cell physiology and human diseases.

• Klíčová slova
• HSP, aggregation, cancer, chaperone, neurodegenerative disease, protein folding,
• MeSH
• lidé MeSH
• neurodegenerativní nemoci metabolismus   genetika   MeSH
• proteiny tepelného šoku * metabolismus   genetika   MeSH
• sbalování proteinů * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• proteiny tepelného šoku * MeSH

Stress responses play a vital role in cellular survival against environmental challenges, often exploited by cancer cells to proliferate, counteract genomic instability, and resist therapeutic stress. Heat shock factor protein 1 (HSF1), a central transcription factor in stress response pathways, exhibits markedly elevated activity in cancer. Despite extensive research into the transcriptional role of HSF1, the mechanisms underlying its activation remain elusive. Upon exposure to conditions that induce protein damage, monomeric HSF1 undergoes rapid conformational changes and assembles into trimers, a key step for DNA binding and transactivation of target genes. This study investigates the role of HSF1 as a sensor of proteotoxic stress conditions. Our findings reveal that purified HSF1 maintains a stable monomeric conformation independent of molecular chaperones in vitro. Moreover, while it is known that heat stress triggers HSF1 trimerization, a notable increase in trimerization and DNA binding was observed in the presence of protein-based crowders. Conditions inducing protein misfolding and increased protein crowding in cells directly trigger HSF1 trimerization. In contrast, proteosynthesis inhibition, by reducing denatured proteins in the cell, prevents HSF1 activation. Surprisingly, HSF1 remains activated under proteotoxic stress conditions even when bound to Hsp70 and Hsp90. This finding suggests that the negative feedback regulation between HSF1 and chaperones is not directly driven by their interaction but is realized indirectly through chaperone-mediated restoration of cytoplasmic proteostasis. In summary, our study suggests that HSF1 serves as a molecular crowding sensor, trimerizing to initiate protective responses that enhance chaperone activities to restore homeostasis.

• MeSH
• DNA vazebné proteiny metabolismus   chemie   genetika   MeSH
• lidé MeSH
• multimerizace proteinu MeSH
• proteiny tepelného šoku HSP70 metabolismus   chemie   MeSH
• reakce na tepelný šok MeSH
• sbalování proteinů * MeSH
• transkripční faktory tepelného šoku * metabolismus   genetika   chemie   MeSH
• transkripční faktory metabolismus   chemie   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• HSF1 protein, human MeSH Prohlížeč
• proteiny tepelného šoku HSP70 MeSH
• transkripční faktory tepelného šoku * MeSH
• transkripční faktory MeSH

Genome stability is significantly influenced by the precise coordination of chromatin complexes that facilitate the loading and eviction of histones from chromatin during replication, transcription, and DNA repair processes. In this study, we investigate the role of the Arabidopsis H3 histone chaperones ANTI-SILENCING FUNCTION 1 (ASF1) and HISTONE REGULATOR A (HIRA) in the maintenance of telomeres and 45S rDNA loci, genomic sites that are particularly susceptible to changes in the chromatin structure. We find that both ASF1 and HIRA are essential for telomere length regulation, as telomeres are significantly shorter in asf1a1b and hira mutants. However, these shorter telomeres remain localized around the nucleolus and exhibit a comparable relative H3 occupancy to the wild type. In addition to regulating telomere length, ASF1 and HIRA contribute to silencing 45S rRNA genes and affect their copy number. Besides, ASF1 supports global heterochromatin maintenance. Our findings also indicate that ASF1 transiently binds to the TELOMERE REPEAT BINDING 1 protein and the N terminus of telomerase in vivo, suggesting a physical link between the ASF1 histone chaperone and the telomere maintenance machinery.

• Klíčová slova
• 45S rDNA, ASF1, Arabidopsis thaliana, HIRA, chromatin, histone chaperones, telomeres,
• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• heterochromatin metabolismus   genetika   MeSH
• histonové chaperony * metabolismus   genetika   MeSH
• histony metabolismus   genetika   MeSH
• homeostáza telomer MeSH
• molekulární chaperony metabolismus   genetika   MeSH
• proteiny buněčného cyklu metabolismus   genetika   MeSH
• proteiny huseníčku * metabolismus   genetika   MeSH
• ribozomální DNA * genetika   metabolismus   MeSH
• RNA ribozomální genetika   metabolismus   MeSH
• sestřihové faktory MeSH
• telomerasa genetika   metabolismus   MeSH
• telomery * metabolismus   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• At2g20020 protein, Arabidopsis MeSH Prohlížeč
• heterochromatin MeSH
• histonové chaperony * MeSH
• histony MeSH
• molekulární chaperony MeSH
• proteiny buněčného cyklu MeSH
• proteiny huseníčku * MeSH
• ribozomální DNA * MeSH
• RNA ribozomální MeSH
• RNA, ribosomal, 45S MeSH Prohlížeč
• sestřihové faktory MeSH
• telomerasa MeSH

Geldanamycin remains a driver in the medicinal chemistry of heat shock protein 90 (Hsp90) inhibition, even half a century after its original isolation from nature. This Perspective focuses on the properties of the benzoquinone ring of the natural product that enable a range of functionalization reactions to take place. Therefore, inherent reactivity at C-17, where the methoxy group serves as a vinylogous ester, and at C-19 that demonstrates nucleophilic, enamide-type character toward electrophiles, and also as a conjugate acceptor to react with nucleophiles, has facilitated the synthesis of semisynthetic derivatives. Thus, a range of C-17-substituted amine derivatives has been investigated in oncology applications, with a number of compounds in this series reaching clinical trials. In contrast, the 19-position of geldanamycin has received less attention, although 19-substituted derivatives offer promise with markedly reduced toxicity compared to geldanamycin itself, while retaining Hsp90 inhibitory activity albeit with diminished potency in cellular studies.

• MeSH
• antitumorózní látky farmakologie   chemie   chemická syntéza   MeSH
• benzochinony * chemie   farmakologie   chemická syntéza   MeSH
• chemie farmaceutická metody   MeSH
• lidé MeSH
• makrocyklické laktamy * chemie   farmakologie   chemická syntéza   MeSH
• proteiny tepelného šoku HSP90 * antagonisté a inhibitory   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• benzochinony * MeSH
• geldanamycin MeSH Prohlížeč
• makrocyklické laktamy * MeSH
• proteiny tepelného šoku HSP90 * MeSH

The ATP-independent chaperone SurA protects unfolded outer membrane proteins (OMPs) from aggregation in the periplasm of Gram-negative bacteria, and delivers them to the β-barrel assembly machinery (BAM) for folding into the outer membrane (OM). Precisely how SurA recognises and binds its different OMP clients remains unclear. Escherichia coli SurA comprises three domains: a core and two PPIase domains (P1 and P2). Here, by combining methyl-TROSY NMR, single-molecule Förster resonance energy transfer (smFRET), and bioinformatics analyses we show that SurA client binding is mediated by two binding hotspots in the core and P1 domains. These interactions are driven by aromatic-rich motifs in the client proteins, leading to SurA core/P1 domain rearrangements and expansion of clients from collapsed, non-native states. We demonstrate that the core domain is key to OMP expansion by SurA, and uncover a role for SurA PPIase domains in limiting the extent of expansion. The results reveal insights into SurA-OMP recognition and the mechanism of activation for an ATP-independent chaperone, and suggest a route to targeting the functions of a chaperone key to bacterial virulence and OM integrity.

• MeSH
• ABC transportéry metabolismus   chemie   genetika   MeSH
• adenosintrifosfát metabolismus   MeSH
• Escherichia coli * metabolismus   genetika   MeSH
• molekulární chaperony * metabolismus   MeSH
• molekulární modely MeSH
• peptidylprolylisomerasa * metabolismus   genetika   MeSH
• proteinové domény MeSH
• proteiny vnější bakteriální membrány metabolismus   genetika   chemie   MeSH
• proteiny z Escherichia coli * metabolismus   genetika   chemie   MeSH
• rezonanční přenos fluorescenční energie MeSH
• sbalování proteinů MeSH
• transportní proteiny * metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportéry MeSH
• adenosintrifosfát MeSH
• molekulární chaperony * MeSH
• peptidylprolylisomerasa * MeSH
• proteiny vnější bakteriální membrány MeSH
• proteiny z Escherichia coli * MeSH
• SurA protein, E coli MeSH Prohlížeč
• transportní proteiny * MeSH

AIMS: Endoplasmic reticulum stress followed by the unfolded protein response is one of the cellular mechanisms contributing to the progression of α-synuclein pathology in Parkinson's disease and other Lewy body diseases. We aimed to investigate the activation of endoplasmic reticulum stress and its correlation with α-synuclein pathology in human post-mortem brain tissue. METHODS: We analysed brain tissue from 45 subjects-14 symptomatic patients with Lewy body disease, 19 subjects with incidental Lewy body disease, and 12 healthy controls. The analysed brain regions included the medulla, pons, midbrain, striatum, amygdala and entorhinal, temporal, frontal and occipital cortex. We analysed activation of endoplasmic reticulum stress via levels of the unfolded protein response-related proteins (Grp78, eIF2α) and endoplasmic reticulum stress-regulating neurotrophic factors (MANF, CDNF). RESULTS: We showed that regional levels of two endoplasmic reticulum-localised neurotrophic factors, MANF and CDNF, did not change in response to accumulating α-synuclein pathology. The concentration of MANF negatively correlated with age in specific regions. eIF2α was upregulated in the striatum of Lewy body disease patients and correlated with increased α-synuclein levels. We found the upregulation of chaperone Grp78 in the amygdala and nigral dopaminergic neurons of Lewy body disease patients. Grp78 levels in the amygdala strongly correlated with soluble α-synuclein levels. CONCLUSIONS: Our data suggest a strong but regionally specific change in Grp78 and eIF2α levels, which positively correlates with soluble α-synuclein levels. Additionally, MANF levels decreased in dopaminergic neurons in the substantia nigra. Our research suggests that endoplasmic reticulum stress activation is not associated with Lewy pathology but rather with soluble α-synuclein concentration and disease progression.

• Klíčová slova
• ER stress, Lewy body disease, Parkinson's disease, alpha‐synuclein, unfolded protein response,
• MeSH
• alfa-synuklein * metabolismus   MeSH
• biologické markery metabolismus   MeSH
• chaperon endoplazmatického retikula BiP * metabolismus   MeSH
• demence s Lewyho tělísky * patologie   metabolismus   MeSH
• eukaryotický iniciační faktor 2 * metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mozek metabolismus   patologie   MeSH
• neurotrofní faktory metabolismus   MeSH
• proteiny tepelného šoku * metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• signální dráha UPR * fyziologie   MeSH
• stres endoplazmatického retikula fyziologie   MeSH
• upregulace * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alfa-synuklein * MeSH
• biologické markery MeSH
• chaperon endoplazmatického retikula BiP * MeSH
• EIF2S1 protein, human MeSH Prohlížeč
• eukaryotický iniciační faktor 2 * MeSH
• HSPA5 protein, human MeSH Prohlížeč
• MANF protein, human MeSH Prohlížeč
• neurotrofní faktory MeSH
• proteiny tepelného šoku * MeSH
• SNCA protein, human MeSH Prohlížeč

Activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) is driven by aberrant activation of the B-cell receptor (BCR) and the TLR/MyD88 signaling pathways. The heat-shock protein HSP110 is a candidate for their regulation as it stabilizes MyD88. However, its role in overall BCR signaling remains unknown. Here, we used first-in-class HSP110 inhibitors to address this question. HSP110 inhibitors decreased the survival of several ABC-DLBCL cell lines in vitro and in vivo, and reduced the phosphorylation of BCR signaling kinases, including BTK and SYK. We identified an interaction between HSP110 and SYK and demonstrated that HSP110 promotes SYK phosphorylation. Finally, the combination of the HSP110 inhibitor with the PI3K inhibitor copanlisib decreases SYK/BTK and AKT phosphorylation synergistically, leading to suppression of tumor growth in cell line xenografts and strong reduction in patient-derived xenografts. In conclusion, by regulating the BCR/TLR signaling pathway, HSP110 inhibitors are potential drug candidates for ABC-DLBCL patients.

• MeSH
• chinazoliny MeSH
• difúzní velkobuněčný B-lymfom * farmakoterapie   metabolismus   patologie   MeSH
• fosforylace účinky léků   MeSH
• kinasa Syk * antagonisté a inhibitory   metabolismus   MeSH
• lidé MeSH
• myši SCID MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové buňky kultivované MeSH
• proteiny tepelného šoku HSP110 * metabolismus   MeSH
• pyrimidiny farmakologie   MeSH
• receptory antigenů B-buněk * metabolismus   MeSH
• signální transdukce * účinky léků   MeSH
• xenogenní modely - testy antitumorózní aktivity * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chinazoliny MeSH
• copanlisib MeSH Prohlížeč
• kinasa Syk * MeSH
• proteiny tepelného šoku HSP110 * MeSH
• pyrimidiny MeSH
• receptory antigenů B-buněk * MeSH
• SYK protein, human MeSH Prohlížeč