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Project description:Interferon-gamma (IFNg) exerts potent growth inhibitory (antiproliferative/pro-apoptotic) effects on a wide range of tumors, including melanoma. While several terminal effectors of cell cycle arrest and apoptosis have been identified, a definitive account of the signaling pathway leading to these events is lacking. We set up a chemical genomics screen and a whole genome targeting CRISPR/Cas9 screen in a growth inhibition (GI)-sensitive patient-derived melanoma (PDM) cell line. Drug screening revealed that treatment with RAF and ERK inhibitors disrupted IFNg GI in PDM cells. For the CRISPR screen, the gene-level analysis showed that the magnitude of enrichment for guide RNAs targeting ERK2 in IFNg-treated cells was comparable to core IFNg signaling proteins like IFNGR2, JAK1, JAK2, and STAT1. We validated the involvement of ERK by detecting a sustained increase in phospho-ERK1/2 (p-ERK) levels following IFNg treatment. In live imaging experiments, we found that an ERK inhibitor (ERKi) blocks the induction of cell death in 17 of 23 (~74%) IFNg-sensitive PDM lines covering all the MAPK mutant and triple wildtype molecular subtypes. Through gene expression analysis, we found that IFNg-ERK signaling triggered the expression of stress response genes and subsequent upregulation of DR5 and NOXA, which were both critical for the induction of cell death. In summary, the IFNg-ERK signaling axis mediates cell death downstream of IFNg treatment in melanoma cells. Our results provide a new understanding of the IFNg-mediated GI pathway that will also be crucial to define mechanisms of GI resistance in tumor cells.
2023-10-06 | GSE235235 | GEO
Project description:Interferon-gamma (IFNg) exerts potent growth inhibitory (antiproliferative/pro-apoptotic) effects on a wide range of tumors, including melanoma. While several terminal effectors of cell cycle arrest and apoptosis have been identified, a definitive account of the signaling pathway leading to these events is lacking. We set up a chemical genomics screen and a whole genome targeting CRISPR/Cas9 screen in a growth inhibition (GI)-sensitive patient-derived melanoma (PDM) cell line. Drug screening revealed that treatment with RAF and ERK inhibitors disrupted IFNg GI in PDM cells. For the CRISPR screen, the gene-level analysis showed that the magnitude of enrichment for guide RNAs targeting ERK2 in IFNg-treated cells was comparable to core IFNg signaling proteins like IFNGR2, JAK1, JAK2, and STAT1. We validated the involvement of ERK by detecting a sustained increase in phospho-ERK1/2 (p-ERK) levels following IFNg treatment. In live imaging experiments, we found that an ERK inhibitor (ERKi) blocks the induction of cell death in 17 of 23 (~74%) IFNg-sensitive PDM lines covering all the MAPK mutant and triple wildtype molecular subtypes. Through gene expression analysis, we found that IFNg-ERK signaling triggered the expression of stress response genes and subsequent upregulation of DR5 and NOXA, which were both critical for the induction of cell death. In summary, the IFNg-ERK signaling axis mediates cell death downstream of IFNg treatment in melanoma cells. Our results provide a new understanding of the IFNg-mediated GI pathway that will also be crucial to define mechanisms of GI resistance in tumor cells.
2023-10-06 | GSE235237 | GEO
Project description:ERK signaling plays an essential role in the IFNg-mediated apoptosis of melanoma cells.
| PRJNA985589 | ENA
Project description:ERK signaling plays an essential role in the IFNg-mediated apoptosis of melanoma cells. [RNAseq]
| PRJNA985598 | ENA
Project description:ERK signaling plays an essential role in the IFNg-mediated apoptosis of melanoma cells. [CRISPR screen]
| PRJNA985597 | ENA
Project description:Survivin was initially described as an inhibitor of apoptosis and attracted growing attention as one of the most tumor-specific genes in the human genome and a promising target for cancer therapy. Lately, it has been shown that survivin is a multifunctional protein that takes part in several crucial cell processes. At first, it was supposed that survivin functions only as a homodimer, but now data indicate that many processes require monomeric survivin. Moreover, recent studies reveal a special mechanism regulating the balance between monomeric and dimeric forms of the protein. In this paper we studied the mutant form of survivin that was unable to dimerize and investigated its role in apoptosis. We showed that survivin monomer interacts with Smac/DIABLO and X-linked inhibitor of apoptosis protein (XIAP) both in vitro and in vivo. Due to this feature, it protects cells from caspase-dependent apoptosis even more efficiently than the wild-type survivin. We also identified that mutant monomeric survivin prevents apoptosis-inducing factor release from the mitochondrial intermembrane space, protecting human fibrosarcoma HT1080 cells from caspase-independent apoptosis. On the other hand, our results indicate that only wild-type survivin, but not the monomer mutant form, enhances tubulin stability in cells. These findings suggest that survivin partly performs its functions as a monomer and partly as a dimer. The mechanism of dimer-monomer balance regulation may also work as a "switcher" between survivin functions and thereby explain remarkable functional diversities of this protein.
| S-EPMC3123095 | biostudies-literature
Project description:Methamphetamine (METH) is an extremely addictive stimulant drug that is widely used with high potential of abuse. Previous studies have shown that METH exposure damages the nervous system, especially dopaminergic neurons. However, the exact molecular mechanisms of METH-induced neurotoxicity remain unclear. We hypothesized that caspase-11 is involved in METH-induced neuronal apoptosis. We tested our hypothesis by examining the change of caspase-11 protein expression in dopaminergic neurons (PC12 and SH-SY5Y) and in the midbrain of rats exposed to METH with Western blotting. We also determined the effects of blocking caspase-11 expression with wedelolactone (a specific inhibitor of caspase-11) or siRNA on METH-induced apoptosis in PC12 cells and SH-SY5Y cells using Annexin V and TUNEL staining. Furthermore, we observed the protein expression changes of the apoptotic markers, cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase 1 (PARP), after silencing the caspase-11 expression in rat midbrain by injecting LV-shcasp11 lentivirus using a stereotaxic positioning system. Results showed that METH exposure increased caspase-11 expression both in vitro and in vivo, with the effects in vitro being dose- and time-dependent. Inhibition of caspase-11 expression with either wedelolactone or siRNAs reduced the number of METH-induced apoptotic cells. In addition, blocking caspase-11 expression inhibited METH-induced activation of caspase-3 and PARP in vitro and in vivo, suggesting that caspase-11/caspase-3 signal pathway is involved in METH-induced neurotoxicity. These results indicate that caspase-11 plays an essential role in METH-induced neuronal apoptosis and may be a potential gene target for therapeutics in METH-caused neurotoxicity.
| S-EPMC4833032 | biostudies-literature
Project description:BackgroundThe severe unfavorable effects of doxorubicin on the heart restrict its clinical usage. Numerous investigations document that cyclic GMP-AMP synthase (cGAS) activator of interferon genes (STING) cascade influences inflammation along with the immune response in a variety of diseases. The pathophysiological function of the cGAS-STING cascade in Doxorubicin-induced cardiomyopathy (DIC) is, nevertheless, unknown.MethodsIn vivo, cardiotoxicity was triggered by a single dose of intra-peritoneal inoculation of doxorubicin (15 mg/kg) in wild-type C57BL/6J mice and STING knockdown animals. Adeno-associated virus 9 (AAV9) was utilized to silence STING. qPCR along with Western blotting were adopted to assess alterations in the cGAS/STING cascade. To assess cardiac function, we employed echocardiography coupled with histology, as well as molecular phenotyping. In vitro, HL-1 cardiomyocytes were introduced as test models.ResultsIn wild type mice, doxorubicin stimulation significantly activated the cGAS/STING pathway. STING silencing increased rate of survival along with heart function in mice, as well as diminished myocardial inflammatory cytokines along with apoptosis. These observations were also confirmed by utilizing siRNA of STING in vitro studies.ConclusionThis research premise established that STING inhibition could alleviate Dox-triggered cardiotoxicity in mice. As a result, preventing DIC by repressing STING in cardiomyocytes might be a possible treatment approach.
| S-EPMC10037834 | biostudies-literature
Project description:Angiogenesis is a precise process mediated by a variety of signals and the environmental niche. Although the essential trace element zinc and its homeostasis are essential for maintaining proper cellular functions, whether zinc plays a role in angiogenesis is currently unknown. Using zebrafish embryos as a model system, we found that zinc treatment significantly increased the expression of the slc39a5 gene, which encodes the zinc transporter Slc39a5. Moreover, knocking down slc39a5 expression using either a morpholino or CRISPR/Cas9-mediated gene editing led to cardiac ischaemia and an accumulation of red blood cells in the caudal vein plexus (CVP), as well as delayed venous sprouting and fewer vascular loops in the CVP region during early development. Further analysis revealed significantly reduced proliferation and delayed cell migration in the caudal vein of slc39a5 morphants. At the mechanistic level, we found increased levels of systemic zinc in slc39a5-deficient embryos, and chelating zinc restored CVP development. In addition, we found that zinc overload in wild-type embryos leads to impaired CVP formation. Taken together, these results indicate that Slc39a5 plays a critical role in endothelial sprouting and migration in venous angiogenesis by regulating zinc homeostasis.
| S-EPMC7653363 | biostudies-literature
Project description:Constitutive activation of MEK-ERK signaling is often found in melanomas. Here, we identify a mechanism that links ERK with JNK signaling in human melanoma. Constitutively active ERK increases c-Jun transcription and stability, which are mediated by CREB and GSK3, respectively. Subsequently, c-Jun increases transcription of target genes, including RACK1, an adaptor protein that enables PKC to phosphorylate and enhance JNK activity, enforcing a feed-forward mechanism of the JNK-Jun pathway. Activated c-Jun is also responsible for elevated cyclin D1 expression, which is frequently overexpressed in human melanoma. Our data reveal that, in human melanoma, the rewired ERK signaling pathway upregulates JNK and activates the c-Jun oncogene and its downstream targets, including RACK1 and cyclin D1.
| S-EPMC1978100 | biostudies-literature