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Anticancer Research Jul 2024Pulsed electromagnetic field (PEMF) stimulation enhances the efficacy of several anticancer drugs. Doxorubicin is an anticancer drug used to treat various types of...
BACKGROUND/AIM
Pulsed electromagnetic field (PEMF) stimulation enhances the efficacy of several anticancer drugs. Doxorubicin is an anticancer drug used to treat various types of cancer, including breast cancer. However, the effect of PEMF stimulation on the efficacy of doxorubicin and the underlying mechanisms remain unclear. Thus, this study aimed to investigate the effect of PEMF stimulation on the anticancer activity of doxorubicin in MDA-MB-231 human breast cancer cells.
MATERIALS AND METHODS
MDA-MB-231 cells were seeded and allowed to incubate for 48 h. The cells were treated with doxorubicin, cisplatin, 5-fluorouracil, or paclitaxel for 48 h. Subsequently, the cells were stimulated with a 60-min PEMF session thrice a day (with an interval of 4 h between each session) for 24 or 48 h. Cell viability was assessed by trypan blue dye exclusion assay and cell-cycle analysis was analyzed by flow cytometry. Molecular mechanisms involved in late G arrest were confirmed by a western blot assay and confocal microscopy.
RESULTS
MDA-MB-231 cells treated with a combination of doxorubicin and PEMF had remarkably lower viability than those treated with doxorubicin alone. PEMF stimulation increased doxorubicin-induced cell-cycle arrest in the late G phase by suppressing cyclin-dependent kinase 1 (CDK1) activity through the enhancement of myelin transcription factor 1 (MYT1) expression, cell division cycle 25C (CDC25C) phosphorylation, and stratifin (14-3-3σ) expression. PEMF also increased doxorubicin-induced DNA damage by inhibiting DNA topoisomerase II alpha (TOP2A).
CONCLUSION
These findings support the use of PEMF stimulation as an adjuvant to strengthen the antiproliferative effect of doxorubicin on breast cancer cells.
Topics: Humans; Doxorubicin; Breast Neoplasms; Female; Cell Line, Tumor; Cell Survival; G2 Phase Cell Cycle Checkpoints; Electromagnetic Fields; DNA Topoisomerases, Type II; Cell Proliferation; Paclitaxel; Fluorouracil; Poly-ADP-Ribose Binding Proteins; cdc25 Phosphatases; Cyclin-Dependent Kinase 2
PubMed: 38925852
DOI: 10.21873/anticanres.17096 -
Cells Jun 2024Resveratrol is a polyphenol known to have metabolic as well as circadian effects. However, there is little information regarding the metabolic and circadian effect of...
Resveratrol is a polyphenol known to have metabolic as well as circadian effects. However, there is little information regarding the metabolic and circadian effect of resveratrol on muscle cells. We sought to investigate the metabolic impact of resveratrol throughout the circadian cycle to clarify the associated signaling pathways. C2C12 myotubes were incubated with resveratrol in the presence of increasing concentrations of glucose, and metabolic and clock proteins were measured for 24 h. Resveratrol led to SIRT1, AMPK and PP2A activation. Myotubes treated with increasing glucose concentrations showed higher activation of the mTOR signaling pathway. However, resveratrol did not activate the mTOR signaling pathway, except for P70S6K and S6. In accordance with the reduced mTOR activity, resveratrol led to advanced circadian rhythms and reduced levels of pBMAL1 and CRY1. Resveratrol increased myogenin expression and advanced its rhythms. In conclusion, resveratrol activates the SIRT1-AMPK-PP2A axis, advances circadian rhythms and induces muscle development.
Topics: Resveratrol; Sirtuin 1; Animals; Mice; Muscle Fibers, Skeletal; Protein Phosphatase 2; AMP-Activated Protein Kinases; Circadian Rhythm; Signal Transduction; Cell Line; Glucose; Muscle Development; TOR Serine-Threonine Kinases
PubMed: 38920697
DOI: 10.3390/cells13121069 -
Nature Communications Jun 2024SDS22 forms an inactive complex with nascent protein phosphatase PP1 and Inhibitor-3. SDS22:PP1:Inhibitor-3 is a substrate for the ATPase p97/VCP, which liberates PP1...
SDS22 forms an inactive complex with nascent protein phosphatase PP1 and Inhibitor-3. SDS22:PP1:Inhibitor-3 is a substrate for the ATPase p97/VCP, which liberates PP1 for binding to canonical regulatory subunits. The exact role of SDS22 in PP1-holoenzyme assembly remains elusive. Here, we show that SDS22 stabilizes nascent PP1. In the absence of SDS22, PP1 is gradually lost, resulting in substrate hyperphosphorylation and a proliferation arrest. Similarly, we identify a female individual with a severe neurodevelopmental disorder bearing an unstable SDS22 mutant, associated with decreased PP1 levels. We furthermore find that SDS22 directly binds to Inhibitor-3 and that this is essential for the stable assembly of SDS22:PP1: Inhibitor-3, the recruitment of p97/VCP, and the extraction of SDS22 during holoenzyme assembly. SDS22 with a disabled Inhibitor-3 binding site co-transfers with PP1 to canonical regulatory subunits, thereby forming non-functional holoenzymes. Our data show that SDS22, through simultaneous interaction with PP1 and Inhibitor-3, integrates the major steps of PP1 holoenzyme assembly.
Topics: Protein Phosphatase 1; Humans; Holoenzymes; Female; Phosphorylation; Protein Binding; HEK293 Cells; Valosin Containing Protein
PubMed: 38918402
DOI: 10.1038/s41467-024-49746-4 -
Drug Design, Development and Therapy 2024Nepetoidin B (NB) has been reported to possess anti-inflammatory, antibacterial, and antioxidant properties. However, its effects on liver ischemia/reperfusion (I/R)...
BACKGROUND
Nepetoidin B (NB) has been reported to possess anti-inflammatory, antibacterial, and antioxidant properties. However, its effects on liver ischemia/reperfusion (I/R) injury remain unclear.
METHODS
In this study, a mouse liver I/R injury model and a mouse AML12 cell hypoxia reoxygenation (H/R) injury model were used to investigate the potential role of NB. Serum transaminase levels, liver necrotic area, cell viability, oxidative stress, inflammatory response, and apoptosis were evaluated to assess the effects of NB on liver I/R and cell H/R injury. Quantitative polymerase chain reaction (qPCR) and Western blotting were used to measure mRNA and protein expression levels, respectively. Molecular docking was used to predict the binding capacity of NB and mitogen-activated protein kinase phosphatase 5 (MKP5).
RESULTS
The results showed that NB significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver necrosis, oxidative stress, reactive oxygen species (ROS) content, inflammatory cytokine content and expression, inflammatory cell infiltration, and apoptosis after liver I/R and AML12 cells H/R injury. Additionally, NB inhibited the JUN protein amino-terminal kinase (JNK)/P38 pathway. Molecular docking results showed good binding between NB and MKP5 proteins, and Western blotting results showed that NB increased the protein expression of MKP5. MKP5 knockout (KO) significantly diminished the protective effects of NB against liver injury and its inhibitory effects on the JNK/P38 pathway.
CONCLUSION
NB exerts hepatoprotective effects against liver I/R injury by regulating the MKP5-mediated P38/JNK signaling pathway.
Topics: Animals; Reperfusion Injury; Mice; Male; Mice, Inbred C57BL; p38 Mitogen-Activated Protein Kinases; Liver; Molecular Docking Simulation; Dual-Specificity Phosphatases; Dose-Response Relationship, Drug; MAP Kinase Signaling System; Structure-Activity Relationship; Disease Models, Animal; Molecular Structure; Oxidative Stress
PubMed: 38911032
DOI: 10.2147/DDDT.S457130 -
European Journal of Dermatology : EJD Apr 2024Previous studies reveal that psoriatic arthritis (PsA) and ankylosing spondylitis (AS) share susceptibility genes, such as HLA-B27, demonstrating a degree of genetic...
Previous studies reveal that psoriatic arthritis (PsA) and ankylosing spondylitis (AS) share susceptibility genes, such as HLA-B27, demonstrating a degree of genetic overlap between these diseases. Recent studies have identified a number of novel AS and PsA genetic susceptibility loci, but data on these loci in Chinese PsA patients are limited. To identify candidate genes that confer susceptibility to PsA in Chinese patients with PsA, psoriasis vulgaris (PsV), and healthy controls. Sixteen susceptibility loci, reported in a genome-wide association study of AS, and nine susceptibility loci, reported in candidate gene studies of PsA, were examined. Single-nucleotide polymorphisms (SNPs) were genotyped in 503 patients with PsA, 496 patients with PsV, and 979 healthy controls using the SNPscanTM multiplex SNP genotyping platform. PLINK software and logistic regression analysis were used to estimate the statistical significance of associations. PPP2R3C (rs8006884) was shown to significantly associate with PsA+PsV (p = 1.92×10-3, OR = 1.28) and was suggested to associate with PsV (p = 0.03, OR = 1.19). A suggestive association was also observed between IL-23R (rs12141575) and PsA as well as with axial PsA based on subtype analysis, KIF3A (rs2897442) and PsV, and ERN1 (rs196941) or IFIH1 (rs984971) and axial PsA. Our results suggest that PPP2R3C confers susceptibility to PsA and PsV, and that this gene may be related to the pathogenesis of psoriatic lesions and arthritis. Moreover, our results indicate a possible association between IL-23R, ERN1, or IFIH1 and subtypes of PsA, and between KIF3A and PsV.
Topics: Humans; Arthritis, Psoriatic; Spondylitis, Ankylosing; Male; Polymorphism, Single Nucleotide; Female; Genetic Predisposition to Disease; Asian People; Adult; Middle Aged; Case-Control Studies; China; Receptors, Interleukin; Protein Phosphatase 2; Genotype; Genome-Wide Association Study; Psoriasis; East Asian People
PubMed: 38907550
DOI: 10.1684/ejd.2024.4641 -
Nature Communications Jun 2024Chemoresistance is a main reason for treatment failure in patients with nasopharyngeal carcinoma, but the exact regulatory mechanism underlying chemoresistance in...
Chemoresistance is a main reason for treatment failure in patients with nasopharyngeal carcinoma, but the exact regulatory mechanism underlying chemoresistance in nasopharyngeal carcinoma remains to be elucidated. Here, we identify PJA1 as a key E3 ubiquitin ligase involved in nasopharyngeal carcinoma chemoresistance that is highly expressed in nasopharyngeal carcinoma patients with nonresponse to docetaxel-cisplatin-5-fluorouracil induction chemotherapy. We find that PJA1 facilitates docetaxel resistance by inhibiting GSDME-mediated pyroptosis in nasopharyngeal carcinoma cells. Mechanistically, PJA1 promotes the degradation of the mitochondrial protein PGAM5 by increasing its K48-linked ubiquitination at K88, which further facilitates DRP1 phosphorylation at S637 and reduced mitochondrial reactive oxygen species production, resulting in suppression of GSDME-mediated pyroptosis and the antitumour immune response. PGAM5 knockdown fully restores the docetaxel sensitization effect of PJA1 knockdown. Moreover, pharmacological targeting of PJA1 with the small molecule inhibitor RTA402 enhances the docetaxel sensitivity of nasopharyngeal carcinoma in vitro and in vivo. Clinically, high PJA1 expression indicates inferior survival and poor clinical efficacy of TPF IC in nasopharyngeal carcinoma patients. Our study emphasizes the essential role of E3 ligases in regulating chemoresistance and provides therapeutic strategies for nasopharyngeal carcinoma based on targeting the ubiquitin-proteasome system.
Topics: Humans; Docetaxel; Drug Resistance, Neoplasm; Nasopharyngeal Carcinoma; Cell Line, Tumor; Nasopharyngeal Neoplasms; Pyroptosis; Ubiquitination; Animals; Ubiquitin-Protein Ligases; Mice; Mice, Nude; Female; Dynamins; Reactive Oxygen Species; Phosphoprotein Phosphatases; Male; Xenograft Model Antitumor Assays; Mice, Inbred BALB C; Antineoplastic Agents; Phosphorylation; Mitochondrial Proteins; Fluorouracil; Gene Expression Regulation, Neoplastic; Mitochondria; Cisplatin; Middle Aged; Gasdermins
PubMed: 38906860
DOI: 10.1038/s41467-024-49675-2 -
Progress in Neuro-psychopharmacology &... Jun 2024DARPP-32 (dopamine and cAMP-regulated phosphoprotein Mr. 32 kDa) is a phosphoprotein that is modulated by multiple receptors integrating intracellular pathways and...
DARPP-32 (dopamine and cAMP-regulated phosphoprotein Mr. 32 kDa) is a phosphoprotein that is modulated by multiple receptors integrating intracellular pathways and playing roles in various physiological functions. It is regulated by dopaminergic receptors through the cAMP/protein kinase A (PKA) pathway, which modulates the phosphorylation of threonine 34 (Thr34). When phosphorylated at Thr34, DARPP-32 becomes a potent protein phosphatase-1 (PP1) inhibitor. Since dopamine is involved in the development of GABAergic neurons and DARPP-32 is expressed in the developing brain, it is possible that DARPP-32 has a role in GABAergic neuronal development. We cloned the zebrafish darpp-32 gene (ppp1r1b) gene and observed that it is evolutionarily conserved in its inhibitory domain (Thr34 and surrounding residues) and the docking motif (residues 7-11 (KKIQF)). We also characterized darpp-32 protein expression throughout the 5 days post-fertilization (dpf) zebrafish larval brain by immunofluorescence and demonstrated that darpp-32 is mainly expressed in regions that receive dopaminergic projections (pallium, subpallium, preoptic region, and hypothalamus). We demonstrated that dopamine acutely suppressed darpp-32 activity by reducing the levels of p-darpp-32 in the 5dpf zebrafish larval brain. In addition, the knockdown of darpp-32 resulted in a decrease in the number of GABAergic neurons in the subpallium of the 5dpf larval brain, with a concomitant increase in the number of DAergic neurons. Finally, we demonstrated that darpp-32 downregulation during development reduced the motor behavior of 5dpf zebrafish larvae. Thus, our observations suggest that darpp-32 is an evolutionarily conserved regulator of dopamine receptor signaling and is required for the formation of GABAergic neurons in the developing telencephalon.
PubMed: 38906412
DOI: 10.1016/j.pnpbp.2024.111060 -
ELife Jun 2024The DNA damage response is critical for maintaining genome integrity and is commonly disrupted in the development of cancer. PPM1D (protein phosphatase Mg/Mn-dependent...
The DNA damage response is critical for maintaining genome integrity and is commonly disrupted in the development of cancer. PPM1D (protein phosphatase Mg/Mn-dependent 1D) is a master negative regulator of the response; gain-of-function mutations and amplifications of are found across several human cancers making it a relevant pharmacological target. Here, we used CRISPR/Cas9 screening to identify synthetic-lethal dependencies of uncovering superoxide dismutase-1 (SOD1) as a potential target for -mutant cells. We revealed a dysregulated redox landscape characterized by elevated levels of reactive oxygen species and a compromised response to oxidative stress in -mutant cells. Altogether, our results demonstrate a role for SOD1 in the survival of -mutant leukemia cells and highlight a new potential therapeutic strategy against -mutant cancers.
Topics: Protein Phosphatase 2C; Humans; Superoxide Dismutase-1; Cell Line, Tumor; Leukemia; CRISPR-Cas Systems; Oxidative Stress; Reactive Oxygen Species; Synthetic Lethal Mutations; Mutation
PubMed: 38896450
DOI: 10.7554/eLife.91611 -
Open Biology Jun 2024The transition from oocyte to embryo requires translation of maternally provided transcripts that in is activated by Pan Gu kinase to release a rapid succession of 13...
The transition from oocyte to embryo requires translation of maternally provided transcripts that in is activated by Pan Gu kinase to release a rapid succession of 13 mitotic cycles. Mitotic entry is promoted by several protein kinases that include Greatwall/Mastl, whose Endosulfine substrates antagonize Protein Phosphatase 2A (PP2A), facilitating mitotic Cyclin-dependent kinase 1/Cyclin B kinase activity. Here we show that hyperactive can not only be suppressed by mutants in its Endos substrate but also by mutants in Pan Gu kinase subunits. Conversely, mutants in or which encode a complex that represses hundreds of maternal mRNAs, enhance . Me31B and Trailer Hitch proteins, known substrates of Pan Gu kinase, copurify with Endos. This echoes findings that budding yeast Dhh1, orthologue of Me31B, associates with Igo1/2, orthologues of Endos and substrates of the Rim15, orthologue of Greatwall. derived mutant embryos show reduced Me31B and elevated transcripts for the mitotic activators Cyclin B, Polo and Twine/Cdc25. Together, our findings demonstrate a previously unappreciated conservation of the Greatwall-Endosulfine pathway in regulating translational repressors and its interactions with the Pan Gu kinase pathway to regulate translation and/or stability of maternal mRNAs upon egg activation.
Topics: Animals; Drosophila Proteins; Oocytes; Protein Phosphatase 2; Gene Expression Regulation, Developmental; Protein Biosynthesis; Drosophila melanogaster; Mutation; Female; Protein Serine-Threonine Kinases; Embryo, Nonmammalian; RNA Stability; RNA, Messenger, Stored; DEAD-box RNA Helicases
PubMed: 38896085
DOI: 10.1098/rsob.240065 -
Cell Death & Disease Jun 2024Tauopathies are characterised by the pathological accumulation of misfolded tau. The emerging view is that toxic tau species drive synaptic dysfunction and potentially...
Tauopathies are characterised by the pathological accumulation of misfolded tau. The emerging view is that toxic tau species drive synaptic dysfunction and potentially tau propagation before measurable neurodegeneration is evident, but the underlying molecular events are not well defined. Human non-mutated 0N4R tau (tau) and P301L mutant 0N4R tau (tau) were expressed in mouse primary cortical neurons using adeno-associated viruses to monitor early molecular changes and synaptic function before the onset of neuronal loss. In this model tau was differentially phosphorylated relative to tau with a notable increase in phosphorylation at ser262. Affinity purification - mass spectrometry combined with tandem mass tagging was used to quantitatively compare the tau and tau interactomes. This revealed an enrichment of tau with ribosomal proteins but a decreased interaction with the proteasome core complex and reduced tau degradation. Differences in the interaction of tau with members of a key synaptic calcium-calmodulin signalling pathway were also identified, most notably, increased association with CaMKII but reduced association with calcineurin and the candidate AD biomarker neurogranin. Decreased association of neurogranin to tau corresponded with the appearance of enhanced levels of extracellular neurogranin suggestive of potential release or leakage from synapses. Finally, analysis of neuronal network activity using micro-electrode arrays showed that overexpression of tau promoted basal hyperexcitability coincident with these changes in the tau interactome and implicating tau in specific early alterations in synaptic function.
Topics: Animals; tau Proteins; Humans; Mice; Neurons; Phosphorylation; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Tauopathies; Synapses; Neurogranin; Calcineurin
PubMed: 38890273
DOI: 10.1038/s41419-024-06815-2