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Free Radical Biology & Medicine Aug 2024Despite of yet unknown mechanism, microvascular deposition of oligomeric Tau (oTau) has been implicated in alteration of the Blood-Brain Barrier (BBB) function in...
Despite of yet unknown mechanism, microvascular deposition of oligomeric Tau (oTau) has been implicated in alteration of the Blood-Brain Barrier (BBB) function in Alzheimer's disease (AD) brains. In this study, we employed an in vitro BBB model using primary mouse cerebral endothelial cells (CECs) to investigate the mechanism underlying the effects of oTau on BBB function. We found that exposing CECs to oTau induced oxidative stress through NADPH oxidase, increased oxidative damage to proteins, decreased proteasome activity, and expressions of tight junction (TJ) proteins including occludin, zonula occludens-1 (ZO-1) and claudin-5. These effects were suppressed by the pretreatment with Fasudil, a RhoA/ROCK signaling inhibitor. Consistent with the biochemical alterations, we found that exposing the basolateral side of CECs to oTau in the BBB model disrupted the integrity of the BBB, as indicated by an increase in FITC-dextran transport across the model, and a decrease in trans endothelial electrical resistance (TEER). oTau also increased the transmigration of peripheral blood mononuclear cells (PBMCs) in the BBB model. These functional alterations in the BBB induced by oTau were also suppressed by Fasudil. Taken together, our findings suggest that targeting the RhoA/ROCK pathway can be a potential therapeutic strategy to maintain BBB function in AD.
Topics: Animals; rho-Associated Kinases; Mice; Blood-Brain Barrier; Endothelial Cells; rhoA GTP-Binding Protein; Signal Transduction; Oxidative Stress; 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; tau Proteins; Humans; Alzheimer Disease; Cells, Cultured; Tight Junctions; Zonula Occludens-1 Protein
PubMed: 38815773
DOI: 10.1016/j.freeradbiomed.2024.05.044 -
Acta Biochimica Et Biophysica Sinica May 2024Chikungunya virus (CHIKV) is a neglected arthropod-borne and anthropogenic alphavirus. Over the past two decades, the CHIKV distribution has undergone significant...
Chikungunya virus (CHIKV) is a neglected arthropod-borne and anthropogenic alphavirus. Over the past two decades, the CHIKV distribution has undergone significant changes worldwide, from the original tropics and subtropics regions to temperate regions, which has attracted global attention. However, the interactions between CHIKV and its host remain insufficiently understood, which dampens the need for the development of an anti-CHIKV strategy. In this study, on the basis of the optimal overexpression of non-structural protein 4 (nsP4), we explore host interactions of CHIKV nsP4 using mass spectrometry-based protein-protein interaction approaches. The results reveal that some cellular proteins that interact with nsP4 are enriched in the ubiquitin-proteasome pathway. Specifically, the scaffold protein receptor for activated C kinase 1 (RACK1) is identified as a novel host interactor and regulator of CHIKV nsP4. The inhibition of the interaction between RACK1 and nsP4 by harringtonolide results in the reduction of nsP4, which is caused by the promotion of degradation but not the inhibition of nsP4 translation. Furthermore, the decrease in nsP4 triggered by the RACK1 inhibitor can be reversed by the proteasome inhibitor MG132, suggesting that RACK1 can protect nsP4 from degradation through the ubiquitin-proteasome pathway. This study reveals a novel mechanism by which the host factor RACK1 regulates CHIKV nsP4, which could be a potential target for developing drugs against CHIKV.
PubMed: 38813597
DOI: 10.3724/abbs.2024073 -
Cell Death & Disease May 2024The targeted elimination of radio- or chemotherapy-induced senescent cells by so-called senolytic substances represents a promising approach to reduce tumor relapse as...
The targeted elimination of radio- or chemotherapy-induced senescent cells by so-called senolytic substances represents a promising approach to reduce tumor relapse as well as therapeutic side effects such as fibrosis. We screened an in-house library of 178 substances derived from marine sponges, endophytic fungi, and higher plants, and determined their senolytic activities towards DNA damage-induced senescent HCT116 colon carcinoma cells. The Pan-PI3K-inhibitor wortmannin and its clinical derivative, PX-866, were identified to act as senolytics. PX-866 potently induced apoptotic cell death in senescent HCT116, MCF-7 mammary carcinoma, and A549 lung carcinoma cells, independently of whether senescence was induced by ionizing radiation or by chemotherapeutics, but not in proliferating cells. Other Pan-PI3K inhibitors, such as the FDA-approved drug BAY80-6946 (Copanlisib, Aliqopa®), also efficiently and specifically eliminated senescent cells. Interestingly, only the simultaneous inhibition of both PI3K class I alpha (with BYL-719 (Alpelisib, Piqray®)) and delta (with CAL-101 (Idelalisib, Zydelig®)) isoforms was sufficient to induce senolysis, whereas single application of these inhibitors had no effect. On the molecular level, inhibition of PI3Ks resulted in an increased proteasomal degradation of the CDK inhibitor p21 in all tumor cell lines analyzed. This led to a timely induction of apoptosis in senescent tumor cells. Taken together, the senolytic properties of PI3K-inhibitors reveal a novel dimension of these promising compounds, which holds particular potential when employed alongside DNA damaging agents in combination tumor therapies.
Topics: Humans; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p21; HCT116 Cells; Proteasome Endopeptidase Complex; Apoptosis; Phosphoinositide-3 Kinase Inhibitors; MCF-7 Cells; Proteolysis; A549 Cells; Wortmannin; Senotherapeutics; Class I Phosphatidylinositol 3-Kinases; DNA Damage; Pyrimidines; Quinazolines
PubMed: 38811535
DOI: 10.1038/s41419-024-06755-x -
Frontiers in Immunology 2024In classical Hodgkin lymphoma (cHL), the survival of neoplastic cells is mediated by the activation of NF-κB, JAK/STAT and PI3K/Akt signaling pathways. CK2 is a highly...
INTRODUCTION
In classical Hodgkin lymphoma (cHL), the survival of neoplastic cells is mediated by the activation of NF-κB, JAK/STAT and PI3K/Akt signaling pathways. CK2 is a highly conserved serine/threonine kinase, consisting of two catalytic (α) and two regulatory (β) subunits, which is involved in several cellular processes and both subunits were found overexpressed in solid tumors and hematologic malignancies.
METHODS AND RESULTS
Biochemical analyses and assays showed an impaired expression of CK2 subunits in cHL, with CK2α being overexpressed and a decreased expression of CK2β compared to normal B lymphocytes. Mechanistically, CK2β was found to be ubiquitinated in all HL cell lines and consequently degraded by the proteasome pathway. Furthermore, at basal condition STAT3, NF-kB and AKT are phosphorylated in CK2-related targets, resulting in constitutive pathways activation. The inhibition of CK2 with CX-4945/silmitasertib triggered the de-phosphorylation of NF-κB-S529, STAT3-S727, AKT-S129 and -S473, leading to cHL cell lines apoptosis. Moreover, CX-4945/silmitasertib was able to decrease the expression of the immuno-checkpoint CD274/PD-L1 but not of CD30, and to synergize with monomethyl auristatin E (MMAE), the microtubule inhibitor of brentuximab vedotin.
CONCLUSIONS
Our data point out a pivotal role of CK2 in the survival and the activation of key signaling pathways in cHL. The skewed expression between CK2α and CK2β has never been reported in other lymphomas and might be specific for cHL. The effects of CK2 inhibition on PD-L1 expression and the synergistic combination of CX-4945/silmitasertib with MMAE pinpoints CK2 as a high-impact target for the development of new therapies for cHL.
Topics: Humans; Hodgkin Disease; Casein Kinase II; Signal Transduction; B7-H1 Antigen; Cell Line, Tumor; Phenazines; Naphthyridines; Apoptosis; Gene Expression Regulation, Neoplastic; Phosphorylation
PubMed: 38807597
DOI: 10.3389/fimmu.2024.1393485 -
Journal of Experimental & Clinical... May 2024Ovarian cancer has a high mortality rate mainly due to its resistance to currently used therapies. This resistance has been associated with the presence of cancer stem...
BACKGROUND
Ovarian cancer has a high mortality rate mainly due to its resistance to currently used therapies. This resistance has been associated with the presence of cancer stem cells (CSCs), interactions with the microenvironment, and intratumoral heterogeneity. Therefore, the search for new therapeutic targets, particularly those targeting CSCs, is important for improving patient prognosis. HOOK1 has been found to be transcriptionally altered in a substantial percentage of ovarian tumors, but its role in tumor initiation and development is still not fully understood.
METHODS
The downregulation of HOOK1 was performed in ovarian cancer cell lines using CRISPR/Cas9 technology, followed by growth in vitro and in vivo assays. Subsequently, migration (Boyden chamber), cell death (Western-Blot and flow cytometry) and stemness properties (clonal heterogeneity analysis, tumorspheres assay and flow cytometry) of the downregulated cell lines were analysed. To gain insights into the specific mechanisms of action of HOOK1 in ovarian cancer, a proteomic analysis was performed, followed by Western-blot and cytotoxicity assays to confirm the results found within the mass spectrometry. Immunofluorescence staining, Western-blotting and flow cytometry were also employed to finish uncovering the role of HOOK1 in ovarian cancer.
RESULTS
In this study, we observed that reducing the levels of HOOK1 in ovarian cancer cells reduced in vitro growth and migration and prevented tumor formation in vivo. Furthermore, HOOK1 reduction led to a decrease in stem-like capabilities in these cells, which, however, did not seem related to the expression of genes traditionally associated with this phenotype. A proteome study, along with other analysis, showed that the downregulation of HOOK1 also induced an increase in endoplasmic reticulum stress levels in these cells. Finally, the decrease in stem-like properties observed in cells with downregulated HOOK1 could be explained by an increase in cell death in the CSC population within the culture due to endoplasmic reticulum stress by the unfolded protein response.
CONCLUSION
HOOK1 contributes to maintaining the tumorigenic and stemness properties of ovarian cancer cells by preserving protein homeostasis and could be considered an alternative therapeutic target, especially in combination with inducers of endoplasmic reticulum or proteotoxic stress such as proteasome inhibitors.
Topics: Female; Humans; Ovarian Neoplasms; Mice; Neoplastic Stem Cells; Animals; Autophagy; Cell Line, Tumor; Endoplasmic Reticulum Stress; Proteostasis; Microtubule-Associated Proteins; Cell Proliferation; Cell Movement
PubMed: 38807192
DOI: 10.1186/s13046-024-03071-2 -
Acta Biochimica Et Biophysica Sinica May 2024Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic...
Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic remodeling in multiple myeloma (MM) cells. We have previously demonstrated that GSK126, a specific EZH2 inhibitor, exhibits anti-MM therapeutic efficacy and safety and ; however, its specific mechanism remains unclear. This study shows that GSK126 induces cellular senescence in MM, which is characterized by the accumulation of senescence-associated heterochromatin foci (SAHF) and p21, and increased senescence-associated β galactosidase activity. Furthermore, EZH2 is inhibited in ribonucleotide reductase regulatory subunit M2 (RRM2) overexpression OCI-MY5 and RPMI-8226 cells. RRM2 overexpression inhibits the methyltransferase function of EZH2 and promotes its degradation through the ubiquitin-proteasome pathway, thereby inducing cellular senescence. In this senescence model, Lamin B1, a key component of the nuclear envelope and a marker of senescence, does not decrease but instead undergoes aberrant accumulation. Meanwhile, phosphorylation of extracellular signal-regulated protein kinase (ERK1/2) is significantly increased. The inhibition of ERK1/2 phosphorylation in turn partially restores Lamin B1 level and alleviates senescence. These findings suggest that EZH2 inhibition increases Lamin B1 level and induces senescence by promoting ERK1/2 phosphorylation. These data indicate that EZH2 plays an important role in MM cellular senescence and provide insights into the relationships among Lamin B1, p-ERK1/2, and cellular senescence.
PubMed: 38804044
DOI: 10.3724/abbs.2024077 -
Journal of Biomedical Science May 2024Radioresistance is a key clinical constraint on the efficacy of radiotherapy in lung cancer patients. REV1 DNA directed polymerase (REV1) plays an important role in...
BACKGROUND
Radioresistance is a key clinical constraint on the efficacy of radiotherapy in lung cancer patients. REV1 DNA directed polymerase (REV1) plays an important role in repairing DNA damage and maintaining genomic stability. However, its role in the resistance to radiotherapy in lung cancer is not clear. This study aims to clarify the role of REV1 in lung cancer radioresistance, identify the intrinsic mechanisms involved, and provide a theoretical basis for the clinical translation of this new target for lung cancer treatment.
METHODS
The effect of targeting REV1 on the radiosensitivity was verified by in vivo and in vitro experiments. RNA sequencing (RNA-seq) combined with nontargeted metabolomics analysis was used to explore the downstream targets of REV1. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify the content of specific amino acids. The coimmunoprecipitation (co-IP) and GST pull-down assays were used to validate the interaction between proteins. A ubiquitination library screening system was constructed to investigate the regulatory proteins upstream of REV1.
RESULTS
Targeting REV1 could enhance the radiosensitivity in vivo, while this effect was not obvious in vitro. RNA sequencing combined with nontargeted metabolomics revealed that the difference result was related to metabolism, and that the expression of glycine, serine, and threonine (Gly/Ser/Thr) metabolism signaling pathways was downregulated following REV1 knockdown. LC-MS/MS demonstrated that REV1 knockdown results in reduced levels of these three amino acids and that cystathionine γ-lyase (CTH) was the key to its function. REV1 enhances the interaction of CTH with the E3 ubiquitin ligase Rad18 and promotes ubiquitination degradation of CTH by Rad18. Screening of the ubiquitination compound library revealed that the ubiquitin-specific peptidase 9 X-linked (USP9X) is the upstream regulatory protein of REV1 by the ubiquitin-proteasome system, which remodels the intracellular Gly/Ser/Thr metabolism.
CONCLUSION
USP9X mediates the deubiquitination of REV1, and aberrantly expressed REV1 acts as a scaffolding protein to assist Rad18 in interacting with CTH, promoting the ubiquitination and degradation of CTH and inducing remodeling of the Gly/Ser/Thr metabolism, which leads to radioresistance. A novel inhibitor of REV1, JH-RE-06, was shown to enhance lung cancer cell radiosensitivity, with good prospects for clinical translation.
Topics: Humans; Lung Neoplasms; Ubiquitin-Protein Ligases; Nucleotidyltransferases; Radiation Tolerance; Ubiquitination; DNA-Binding Proteins; Ubiquitin Thiolesterase; Cell Line, Tumor; Mice; Animals; DNA-Directed DNA Polymerase
PubMed: 38802791
DOI: 10.1186/s12929-024-01044-3 -
NPJ Breast Cancer May 2024Triple negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases in the United States. Systemic neoadjuvant chemotherapy (NACT), with or without...
Triple negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases in the United States. Systemic neoadjuvant chemotherapy (NACT), with or without immunotherapy, is the current standard of care for patients with early-stage TNBC. However, up to 70% of TNBC patients have significant residual disease once NACT is completed, which is associated with a high risk of developing recurrence within two to three years of surgical resection. To identify targetable vulnerabilities in chemoresistant TNBC, we generated longitudinal patient-derived xenograft (PDX) models from TNBC tumors before and after patients received NACT. We then compiled transcriptomes and drug response profiles for all models. Transcriptomic analysis identified the enrichment of aberrant protein homeostasis pathways in models from post-NACT tumors relative to pre-NACT tumors. This observation correlated with increased sensitivity in vitro to inhibitors targeting the proteasome, heat shock proteins, and neddylation pathways. Pevonedistat, a drug annotated as a NEDD8-activating enzyme (NAE) inhibitor, was prioritized for validation in vivo and demonstrated efficacy as a single agent in multiple PDX models of TNBC. Pharmacotranscriptomic analysis identified a pathway-level correlation between pevonedistat activity and post-translational modification (PTM) machinery, particularly involving neddylation and sumoylation targets. Elevated levels of both NEDD8 and SUMO1 were observed in models exhibiting a favorable response to pevonedistat compared to those with a less favorable response in vivo. Moreover, a correlation emerged between the expression of neddylation-regulated pathways and tumor response to pevonedistat, indicating that targeting these PTM pathways may prove effective in combating chemoresistant TNBC.
PubMed: 38802426
DOI: 10.1038/s41523-024-00644-4 -
Cureus Apr 2024Introduction Multiple myeloma (MM) is a hematological disorder characterized by aberrant multiplication of malignant plasma cells in the bone marrow. The current...
Real-World Outcomes in Transplant-Ineligible Patients With Newly Diagnosed Multiple Myeloma Treated With Bortezomib/Cyclophosphamide/Dexamethasone and Bortezomib/Lenalidomide/Dexamethasone as Upfront Treatment.
Introduction Multiple myeloma (MM) is a hematological disorder characterized by aberrant multiplication of malignant plasma cells in the bone marrow. The current mainstay of treatment for patients with newly diagnosed MM (NDMM) is a triplet regimen with a proteasome inhibitor, immunomodulatory imide, and dexamethasone. The two most common of these triplet regimens are VLD (bortezomib/lenalidomide/dexamethasone) and VCD (bortezomib/cyclophosphamide/dexamethasone). This study aims to compare the outcomes between these two therapies in transplant-ineligible patients with NDMM. Methods We conducted a retrospective study at the Aga Khan University Hospital in Karachi, Pakistan. All NDMM transplant-ineligible patients either receiving VLD or VCD therapy between January 2015 and December 2022 were included in our study. Hematological parameters before and after treatment were obtained from hospital records. Response to treatment was classified according to the International Myeloma Working Group (IMWG) response criteria as either complete response (CR), very good partial response (VGPR), partial response (PR), minimal response (MR), stable disease (SD), or progressive disease (PD). The response to treatment as well as overall survival (OS) and progression-free survival (PFS) was compared between VCD and VLD therapy. A p-value of 0.05 or less was taken to be statistically significant. Results Twenty (23.8%) patients in the VCD group and 20 (23.0%) in the VLD group underwent complete remission. Seven (8.3%) patients experienced disease progression in the VCD group, while the figure stood at three (3.4%) in the VLD group. There was no statistically significant difference in the overall response rate between the VCD (58; 69.0%) and VLD (70; 80.5%) groups (p=0.086), a difference that was not statistically significant on the Chi-square test. OS was comparable between VCD (69.1 months, 95%CI: 61.3-77.0) and VLD (76.9 months, 95%CI: 69.0-85.0) therapies. Conclusions The study did not identify any statistically significant distinction in the treatment outcomes between the VCD and VLD regimens among NDMM patients ineligible for transplantation. Nevertheless, the study highlights the positive outcomes observed with both treatments in this specific patient cohort. This implies that either regimen could be deemed suitable as a treatment option for patients in low- and middle-income countries. Since both regimens demonstrate comparable effectiveness, assessing the cost-effectiveness of these regimens is crucial. Future research should also explore the economic aspects of the two treatment options.
PubMed: 38800157
DOI: 10.7759/cureus.58999 -
BioRxiv : the Preprint Server For... May 2024Human metapneumovirus (HMPV) is a leading cause of respiratory infections in children, older adults, and those with underlying conditions . HMPV must evade immune...
Human metapneumovirus (HMPV) is a leading cause of respiratory infections in children, older adults, and those with underlying conditions . HMPV must evade immune defenses to replicate successfully; however, the viral proteins used to accomplish this are poorly characterized. The HMPV small hydrophobic (SH) protein has been reported to inhibit signaling through type I and type II interferon (IFN) receptors , in part by preventing STAT1 phosphorylation. HMPV infection also inhibits IL-6 signaling. However, the mechanisms by which SH inhibits signaling, and its involvement in IL-6 signaling inhibition are unknown. Here, we used transfection of SH expression plasmids and SH-deleted virus (ΔSH) to show that SH is the viral factor responsible for inhibition of IL-6 signaling during HMPV infection. Transfection of SH-expression vectors or infection with wildtype, but not ΔSH virus, blocked IL-6 mediated STAT3 activation. Further, JAK1 protein (but not RNA) was significantly reduced in cells infected with wildtype but not ΔSH virus. The SH-mediated reduction of JAK1 was partially restored by addition of proteasome inhibitors, suggesting proteasomal degradation of JAK1. Confocal microscopy indicated that infection relocalized JAK1 to viral replication factories. Co-immunoprecipitation showed that SH interacts with JAK1 and ubiquitin, further linking SH to proteasomal degradation machinery. These data indicate that SH inhibits IL-6 and IFN signaling in infected cells in part by promoting proteasomal degradation of JAK1 and that SH is necessary for IL-6 and IFN signaling inhibition in infection. These findings enhance our understanding of the immune evasion mechanisms of an important respiratory pathogen.
PubMed: 38798421
DOI: 10.1101/2024.05.10.593594