-
Molecular Biology Reports Jun 2024MG132, a proteasome inhibitor, is widely used to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity by proteasome-mediated...
BACKGROUND
MG132, a proteasome inhibitor, is widely used to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity by proteasome-mediated degradation of IκB. It has been marketed as a specific, reversible, cell-permeable and low-cost inhibitor. However, adverse effects of the compound have been reported in the literature. We recently discovered and characterised a point mutation in the acute phase protein serum amyloid A (SAA) in chickens, by overexpressing the protein in chicken hepatocellular carcinoma (LMH) cells. This serine to arginine exchange at amino acid position 90 (SAA.R90S) leads to intra- and extracellular accumulation of SAA, which is surprisingly counteracted by MG132 treatment, independent of SAA's intrinsic promoter.
METHODS AND RESULTS
To test, whether low proteasomal degradation of SAA.R90S is responsible for the observed intra- and extracellular SAA accumulation, we intended to inhibit the proteasome in SAA wild type (SAA.WT) overexpressing cells with MG132. However, we observed an unexpected drastic decrease in SAA protein expression at the transcript level. NF-κB gene expression was unchanged by MG132 at the measured time point.
CONCLUSIONS
The observed results demonstrate that MG132 inhibits SAA expression at the transcript level, independent of its endogenous promoter. Further, the data might indicate that NF-κB is not involved in the observed MG132-induced inhibition of SAA expression. We, consequently, question in this brief report whether MG132 should truly be categorised as a specific ubiquitin proteasome inhibitor and recommend the usage of alternative compounds.
Topics: Animals; Leupeptins; Chickens; Carcinoma, Hepatocellular; Cell Line, Tumor; Liver Neoplasms; Promoter Regions, Genetic; Serum Amyloid A Protein; NF-kappa B; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Gene Expression Regulation, Neoplastic
PubMed: 38896168
DOI: 10.1007/s11033-024-09726-9 -
Cancers Jun 2024Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL),...
Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL), represents a different biology and has a poor prognosis. In this retrospective analysis, we evaluated patients with primary (pPCL, n = 35) or secondary (sPCL, n = 49), with ≥5% CPCs and a smaller subset with lower CPCs of 1-4% (n = 20). The median age was 61 years; 45% were men and 54% were Black. High-risk cytogenetics were found in 87% and extramedullary disease in 47%. For the entire cohort, 75% received a proteasome inhibitor, 70% chemotherapy, 54% an immunomodulatory drug, 24% a daratumumab-based regimen and 26% an autologous stem cell transplant (ASCT). The treatments marginally improved the overall survival (OS) for pPCL vs. sPCL (13 vs. 3.5 months = 0.002). However, the 5-year survival for the whole cohort was dismal at 11%. High-risk cytogenetics, low platelets, extramedullary disease and high LDH were independently associated with poor outcomes. Further research is urgently needed to expand the treatment options and improve the outcomes in PCL.
PubMed: 38893268
DOI: 10.3390/cancers16112149 -
Cancers Jun 2024High expression of the receptor tyrosine kinase (RTK) insulin-like growth factor-1 receptor () and RTK mutations are associated with high-risk/worse prognosis in...
High expression of the receptor tyrosine kinase (RTK) insulin-like growth factor-1 receptor () and RTK mutations are associated with high-risk/worse prognosis in multiple myeloma (MM). Combining the pIGF1R/pINSR inhibitor linsitinib with the proteasome inhibitor (PI) bortezomib seemed promising in a clinical trial, but IGF1R expression was not associated with therapy response. Because the oncogenic impact of mutations is so far unknown, we investigated the functional impact of mutations on survival signaling, viability/proliferation and survival response to therapy. We transfected four human myeloma cell lines (HMCLs) with , and (Sleeping Beauty), generated CRISPR-Cas9 knockouts in the HMCLs U-266 (IGF1R) and L-363 (IGF1R) and tested the anti-MM activity of linsitinib alone and in combination with the second-generation PI carfilzomib in seven HMCLs. knockout entailed reduced proliferation. Upon IGF1R overexpression, survival signaling was moderately increased in all HCMLs and slightly affected by in one HMCL, whereby the viability remained unaffected. Expression of IGF1R reduced pIGF1R-Y1135, especially under serum reduction, but did not impact downstream signaling. Linsitinib and carfilzomib showed enhanced anti-myeloma activity in six out of seven HMCL irrespective of the mutation status. In conclusion, mutations can impact IGF1R activation and/or downstream signaling, and a combination of linsitinib with carfilzomib might be a suitable therapeutic approach for MM patients potentially responsive to IGF1R blockade.
PubMed: 38893258
DOI: 10.3390/cancers16112139 -
Cells Jun 2024Over the past few decades, the worldwide incidence of cutaneous melanoma, a malignant neoplasm arising from melanocytes, has been increasing markedly, leading to the...
Over the past few decades, the worldwide incidence of cutaneous melanoma, a malignant neoplasm arising from melanocytes, has been increasing markedly, leading to the highest rate of skin cancer-related deaths. While localized tumors are easily removed by excision surgery, late-stage metastatic melanomas are refractory to treatment and exhibit a poor prognosis. Consequently, unraveling the molecular mechanisms underlying melanoma tumorigenesis and metastasis is crucial for developing novel targeted therapies. We found that the multiple endocrine neoplasia type 1 (MEN1) gene product Menin is required for the transforming growth factor beta (TGFβ) signaling pathway to induce cell growth arrest and apoptosis in vitro and prevent tumorigenesis in vivo in preclinical xenograft models of melanoma. We further identified point mutations in two MEN1 family members affected by melanoma that led to proteasomal degradation of the MEN1 gene product and to a loss of TGFβ signaling. Interestingly, blocking the proteasome degradation pathway using an FDA-approved drug and RNAi targeting could efficiently restore MEN1 expression and TGFβ transcriptional responses. Together, these results provide new potential therapeutic strategies and patient stratification for the treatment of cutaneous melanoma.
Topics: Melanoma; Humans; Transforming Growth Factor beta; Animals; Cell Line, Tumor; Signal Transduction; Mice; Neoplasm Metastasis; Proto-Oncogene Proteins; Apoptosis; Carcinogenesis; Skin Neoplasms; Proteasome Endopeptidase Complex; Cell Proliferation; Gene Expression Regulation, Neoplastic
PubMed: 38891107
DOI: 10.3390/cells13110973 -
Molecular Diagnosis & Therapy Jul 2024Zevorcabtagene autoleucel () is a fully humanised B cell maturation antigen (BCMA)-targeting specific chimeric antigen receptor (CAR) T-cell therapy being developed by... (Review)
Review
Zevorcabtagene autoleucel () is a fully humanised B cell maturation antigen (BCMA)-targeting specific chimeric antigen receptor (CAR) T-cell therapy being developed by CARsgen for the treatment of multiple myeloma. Zevorcabtagene autoleucel is an autologous CAR T cell comprising a fully human BCMA-specific scFv (25C2), a CD8α hinge region and transmembrane domain, a 4-1BB costimulatory domain and a CD3-ζ T cell activation domain. Zevorcabtagene autoleucel recognizes and induces selective toxicity against BCMA-expressing tumour cells leading to their elimination. In February 2024, zevorcabtagene autoleucel received its first approval in China for the treatment of adults with relapsed or refractory multiple myeloma who have progressed after ≥ 3 prior lines of therapy (including ≥ 1 proteasome inhibitor and an immunomodulatory agent). Clinical studies of zevorcabtagene autoleucel are underway in Canada and the US. This article summarizes the milestones in the development of zevorcabtagene autoleucel leading to this first approval for relapsed or refractory multiple myeloma.
Topics: Humans; Multiple Myeloma; B-Cell Maturation Antigen; Immunotherapy, Adoptive; Receptors, Chimeric Antigen; Clinical Trials as Topic; Drug Approval; Treatment Outcome
PubMed: 38888762
DOI: 10.1007/s40291-024-00723-z -
Investigative Ophthalmology & Visual... Jun 2024Ubiquitination serves as a fundamental post-translational modification in numerous cellular events. Yet, its role in regulating corneal epithelial wound healing (CEWH)...
PURPOSE
Ubiquitination serves as a fundamental post-translational modification in numerous cellular events. Yet, its role in regulating corneal epithelial wound healing (CEWH) remains elusive. This study endeavored to determine the function and mechanism of ubiquitination in CEWH.
METHODS
Western blot and immunoprecipitation were used to discern ubiquitination alterations during CEWH in mice. Interventions, including neuronally expressed developmentally downregulated 4 (Nedd4) siRNA and proteasome/lysosome inhibitor, assessed their impact on CEWH. In vitro analyses, such as the scratch wound assay, MTS assay, and EdU staining, were conducted to gauge cell migration and proliferation in human corneal epithelial cells (HCECs). Moreover, transfection of miR-30/200 coupled with a luciferase activity assay ascertained their regulatory mechanism on Nedd4.
RESULTS
Global ubiquitination levels were markedly increased during the mouse CEWH. Importantly, the application of either proteasomal or lysosomal inhibitors notably impeded the healing process both in vivo and in vitro. Furthermore, Nedd4 was identified as an essential E3 ligase for CEWH. Nedd4 expression was significantly upregulated during CEWH. In vivo studies revealed that downregulation of Nedd4 substantially delayed CEWH, whereas further investigations underscored its role in regulating cell proliferation and migration, through the Stat3 pathway by targeting phosphatase and tensin homolog (PTEN). Notably, our findings pinpointed miR-30/200 family members as direct regulators of Nedd4.
CONCLUSIONS
Ubiquitination holds pivotal significance in orchestrating CEWH. The critical E3 ligase Nedd4, under the regulatory purview of miR-30 and miR-200, facilitates CEWH through PTEN-mediated Stat3 signaling. This revelation sheds light on a prospective therapeutic target within the realm of CEWH.
Topics: Nedd4 Ubiquitin Protein Ligases; Animals; Ubiquitination; Mice; Cell Movement; Cell Proliferation; Wound Healing; PTEN Phosphohydrolase; Epithelium, Corneal; Ubiquitin-Protein Ligases; Humans; Mice, Inbred C57BL; Endosomal Sorting Complexes Required for Transport; Blotting, Western; STAT3 Transcription Factor; Cells, Cultured; Disease Models, Animal; MicroRNAs; Immunoprecipitation; Male; Gene Expression Regulation
PubMed: 38888282
DOI: 10.1167/iovs.65.6.29 -
The Journal of Pathology Jun 2024The evolution of cancer treatment has provided increasingly targeted strategies both in the upfront and relapsed disease settings. Small-molecule inhibitors and... (Review)
Review
The evolution of cancer treatment has provided increasingly targeted strategies both in the upfront and relapsed disease settings. Small-molecule inhibitors and immunotherapy have risen to prominence with chimeric antigen receptor T-cells, checkpoint inhibitors, kinase inhibitors, and monoclonal antibody therapies being deployed across a range of solid organ and haematological malignancies. However, novel approaches are required to target transcription factors and oncogenic fusion proteins that are central to cancer biology and have generally eluded successful drug development. Thalidomide analogues causing protein degradation have been a cornerstone of treatment in multiple myeloma, but a lack of in-depth mechanistic understanding initially limited progress in the field. When the protein cereblon (CRBN) was found to mediate thalidomide analogues' action and CRBN's neo-targets were identified, existing and novel drug development accelerated, with applications outside multiple myeloma, including non-Hodgkin's lymphoma, myelodysplastic syndrome, and acute leukaemias. Critically, transcription factors were the first canonical targets described. In addition to broadening the application of protein-degrading drugs, resistance mechanisms are being overcome and targeted protein degradation is widening the scope of druggable proteins against which existing approaches have been ineffective. Examples of targeted protein degraders include molecular glues and proteolysis targeting chimeras (PROTACs): heterobifunctional molecules that bind to proteins of interest and cause proximity-induced ubiquitination and proteasomal degradation via a linked E3 ligase. Twenty years since their inception, PROTACs have begun progressing through clinical trials, with early success in targeting the oestrogen receptor and androgen receptor in breast and prostate cancer respectively. This review explores important developments in targeted protein degradation to both treat and study cancer. It also considers the potential advantages and challenges in the translational aspects of developing new treatments. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
PubMed: 38886898
DOI: 10.1002/path.6301 -
Biology Direct Jun 2024Long noncoding RNAs (lncRNAs) are implicated in the initiation and progression of diffuse large B-cell lymphoma (DLBCL). Small nucleolar RNA host gene 20 (SNHG20) has...
BACKGROUND
Long noncoding RNAs (lncRNAs) are implicated in the initiation and progression of diffuse large B-cell lymphoma (DLBCL). Small nucleolar RNA host gene 20 (SNHG20) has been recognized as a critical lncRNA in multiple human cancers. However, the role of SNHG20 and its underlying mechanism in DLBCL are still unclear.
METHODS
The expression levels of SNHG20, c-MYC, β-catenin, and ubiquitin-specific peptidase 14 (USP14) were measured by reverse transcription-quantitative polymerase chain reaction (RT‒qPCR) and immunoblotting. Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) incorporation, and flow cytometry assays were used to assess the proliferation and apoptosis of DLBCL cells. The transcriptional regulation of SNHG20 by c-MYC was confirmed by a luciferase reporter assay and RNA immunoprecipitation. The interaction between USP14 and β-catenin was demonstrated using coimmunoprecipitation. A subcutaneous xenograft model was constructed to determine the role of SNHG20 in vivo.
RESULTS
In the present study, we found that SNHG20 expression was upregulated in DLBCL cell lines and tissues compared to their normal counterparts. SNHG20 knockdown prominently reduced the proliferation and induced the apoptosis of U2932 and OCI-LY3 cells. However, SNHG20 overexpression increased the proliferation and apoptosis resistance of DLBCL cells. Mechanistically, the expression of SNHG20 was positively regulated by c-MYC in DLBCL cells. C-MYC directly bound to the promoter of SNHG20 to activate its transcription. SNHG20 was expressed mainly in the cytosol in DLBCL cells. SNHG20 silencing did not impact USP14 expression but markedly decreased the level of β-catenin, the substrate of USP14, in DLBCL cells. USP14 overexpression increased the β-catenin level, and this increase was attenuated by SNHG20 knockdown. Treatment with the proteasome inhibitor MG132 abolished SNHG20 knockdown-induced β-catenin downregulation. Moreover, SNHG20 silencing reduced the half-life but increased the ubiquitination of β-catenin in DLBCL cells. SNHG20 knockdown weakened the interaction between both endogenous and exogenous USP14 and β-catenin. In turn, SNHG20 overexpression increased the c-MYC level, and this increase was attenuated by β-catenin knockdown. Importantly, β-catenin knockdown attenuated the SNHG20-mediated increase in DLBCL cell proliferation in vitro and tumour growth in vivo.
CONCLUSIONS
Taken together, our results suggested that c-MYC-activated SNHG20 accelerated the proliferation and increased the apoptosis resistance of DLBCL cells via USP14-mediated deubiquitination of β-catenin. The c-MYC/SNHG20 positive feedback loop may be a new target for anti-DLBCL treatment.
Topics: RNA, Long Noncoding; Humans; beta Catenin; Cell Proliferation; Lymphoma, Large B-Cell, Diffuse; Proto-Oncogene Proteins c-myc; Cell Line, Tumor; Animals; Mice; Ubiquitination; Ubiquitin Thiolesterase; Gene Expression Regulation, Neoplastic; Apoptosis; Mice, Nude
PubMed: 38886753
DOI: 10.1186/s13062-024-00488-9 -
The Journal of Veterinary Medical... Jun 2024The African pygmy hedgehog (Atelerix albiventris) is known to have a high incidence of tumor. However, investigating the tumors of this species has been constrained by...
The African pygmy hedgehog (Atelerix albiventris) is known to have a high incidence of tumor. However, investigating the tumors of this species has been constrained by the limited availability of research materials such as cell lines and genome information. In this study, we successfully established a novel cell line from a histiocytic sarcoma (HS) of an African pygmy hedgehog, allowing us to conduct a drug screening. We investigated using FDA-approved drug library screening to determine which anticancer drug this tumor cell line is sensitive to, and as a result of apoptosis experiments, bortezomib among the three proteasome inhibitors was found to induce cell death of cancer cells by significantly increasing caspase-3 cleavage (P<0.01). Thus, we elucidated that the proteasome inhibitors, particularly bortezomib, exhibit anti-tumor effects on a cell line derived from an HS in an African pygmy hedgehog through a mechanism comparable to that described in human tumors. This study reports the first characterized cell line from the African pygmy hedgehog and also highlights the potential utility of bortezomib as an anti-tumor treatment for HS in this species.
PubMed: 38880614
DOI: 10.1292/jvms.23-0426 -
European Journal of Pharmacology Aug 2024The transcription factor nuclear factor κB (NF-κB) is activated by proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and Toll-like receptor (TLR)...
Porphyrin derivatives inhibit tumor necrosis factor α-induced gene expression and reduce the expression and increase the cross-linked forms of cellular components of the nuclear factor κB signaling pathway.
The transcription factor nuclear factor κB (NF-κB) is activated by proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and Toll-like receptor (TLR) ligands. Screening of NPDepo chemical libraries identified porphyrin derivatives as anti-inflammatory compounds that strongly inhibited the up-regulation of intercellular adhesion molecule-1 (ICAM-1) expression induced by TNF-α, interleukin-1α, the TLR3 ligand, and TLR4 ligand in human umbilical vein endothelial cells. In the present study, the mechanisms of action of porphyrin derivatives were further elucidated using human lung adenocarcinoma A549 cells. Porphyrin derivatives, i.e., dimethyl-2,7,12,18-tetramethyl-3,8-di(1-methoxyethyl)-21H,23H-porphine-13,17-dipropionate (1) and pheophorbide a (2), inhibited TNF-α-induced ICAM-1 expression and decreased the TNF-α-induced transcription of ICAM-1, vascular cell adhesion molecule-1, and E-selectin genes. 1 and 2 reduced the expression of the NF-κB subunit RelA protein for 1 h, which was not rescued by the inhibition of proteasome- and lysosome-dependent protein degradation. In addition, 1 and 2 decreased the expression of multiple components of the TNF receptor 1 complex, and this was accompanied by the appearance of their cross-linked forms. As common components of the NF-κB signaling pathway, 1 and 2 also cross-linked the α, β, and γ subunits of the inhibitor of NF-κB kinase complex and the NF-κB subunits RelA and p50. Cellular protein synthesis was prevented by 2, but not by 1. Therefore, the present results indicate that porphyrin derivative 1 reduced the expression and increased the cross-linked forms of cellular components required for the NF-κB signaling pathway without affecting global protein synthesis.
Topics: Humans; Signal Transduction; Tumor Necrosis Factor-alpha; Intercellular Adhesion Molecule-1; NF-kappa B; Porphyrins; A549 Cells; E-Selectin; Gene Expression Regulation
PubMed: 38880218
DOI: 10.1016/j.ejphar.2024.176747