scholarly journals Regulation of CHK1 inhibitor resistance by a c-Rel and USP1 dependent pathway

2021 ◽  
Author(s):  
Jill E Hunter ◽  
Amy E Campbell ◽  
Nicola L Hannaway ◽  
Scott Kerridge ◽  
Saimir Luli ◽  
...  
Keyword(s):  
Akt Pathway ◽  
Therapeutic Resistance ◽  
Potential Mechanism ◽  
Wild Type ◽  
Osteosarcoma Cells ◽  
Chk1 Inhibitor ◽  
Inhibitor Resistance ◽  
Dependent Pathway ◽  
Major Defect

We previously discovered that deletion of c-Rel in the Eμ-Myc mouse model of lymphoma results in earlier onset of disease, a finding that contrasted with the expected function of this NF-κB subunit in B-cell malignancies. Here we report that c-rel -/- Eμ-Myc cells have an unexpected and major defect in the CHK1 pathway, with almost undetectable levels of CHK1 and CLSPN protein leading to therapeutic resistance to the highly specific CHK1 inhibitor (CHK1i) CCT244747. Similar downregulation of CHK1 levels was also seen in CCT244747 resistant U2OS osteosarcoma cells. Further investigation revealed that downregulation of the deubiquitinase USP1 is responsible, at least in part, for these effects. Importantly, we demonstrate that c-rel -/- Eμ-Myc lymphoma cells survive though upregulation of compensatory PI3K/AKT pathway activity. Moreover, targeting this pathway with Pictilisib (GDC-0941) effectively killed c-rel -/- Eμ-Myc in vivo, while having no effect on wild type Eμ-Myc cells. This data reveals an NF-κB regulated pathway controlling CHK1 activity in cancer cells and identifies a potential mechanism for both acquiring and overcoming CHK1i resistance in cancer patients.

scholarly journals MyD88-Dependent Signaling Affects the Development of Meningococcal Sepsis by Nonlipooligosaccharide Ligands

2006 ◽  
Vol 74 (6) ◽  
pp. 3538-3546 ◽  
Author(s):  
Laura Plant ◽  
Hong Wan ◽  
Ann-Beth Jonsson
Keyword(s):  
Inflammatory Responses ◽  
Innate Immune ◽  
Meningococcal Sepsis ◽  
Wild Type ◽  
Microbial Infections ◽  
In The Wild ◽  
Myeloid Differentiation Factor ◽  
Dependent Pathway ◽  
Meningococcal Strain

ABSTRACT The Toll-like receptors (TLRs) and the adaptor myeloid differentiation factor 88 (MyD88) are important in the innate immune defenses of the host to microbial infections. Meningococcal ligands signaling via TLRs control inflammatory responses, and stimulation can result in fulminant meningococcal sepsis. In this study, we show that the responses to nonlipooligosaccharide (non-LOS) ligands of meningococci are MyD88 dependent. An isogenic LOS-deficient mutant of the serogroup C meningococcal strain FAM20 caused fatal disease in wild type C57BL/6 mice that was not observed in MyD88−/− mice. Fatality correlated with high proinflammatory cytokine and C5a levels in serum, high neutrophil numbers in blood, and increased bacteremia at 24 h postinfection in the wild-type mice. Infection with the parent strain FAM20 resulted in fatality in 100% of the wild-type mice and 50% of the MyD88−/− mice. We conclude that both LOS and another neisserial ligand cause meningococcal sepsis in an in vivo mouse model and confirm that meningococcal LOS can act via both the MyD88- dependent and -independent pathways, while the non-LOS meningococcal ligand(s) acts only via the MyD88-dependent pathway.

LncRNA GAS5 suppresses the proliferation and invasion of osteosarcoma cells via the miR-23a-3p/PTEN/PI3K/AKT pathway

2020 ◽  
Author(s):  
Jianmin Liu ◽  
Ming Chen ◽  
Longyang Ma ◽  
Xingbo Dang ◽  
Gongliang Du
Keyword(s):  
Tumor Suppressor ◽  
Tumor Growth ◽  
Akt Pathway ◽  
Osteosarcoma Cell ◽  
Osteosarcoma Cells ◽  
Cell Behaviors ◽  
Human Osteosarcoma ◽  
Proliferation And Invasion

Abstract Background: Accumulating evidence has shown that lncRNA growth arrest special 5 (GAS5) is a well‑known tumor suppressor in the pathogenesis of a variety of human cancers. However, the detailed role of GAS5 in osteosarcoma is largely unclear. Here, we explore the role of GAS5 in progression of osteosarcoma. Methods: The expression level of GAS5 was detected in human osteosarcoma tissues and matched adjacent tissues, as well as osteosarcoma cell lines and non-malignant osteoblast cells. Then, in vitro gain- and loss-of-function experiments, with the pcDNA-GAS5 expression vector and GAS5-siRNA, were performed in U2OS and HOS cells to determine the effect of GAS5 on osteosarcoma cell proliferation and invasion. Subsequently, we searched potential miRNA targets with bioinformatics analysis and confirmed their interaction by using luciferase reporter gene and RNA pull-down assays. The function and mechanism of miR-23a-3p in proliferation and invasion was also investigated in U2OS and HOS cells. Furthermore, rescue experiments were performed to verify the involvement of miR-23a-3p and its target gene in GAS5-mediated cell behaviors. Finally, a xenograft nude mouse model was established by subcutaneous injection with U2OS cells overexpressing GAS5 or not, and the effect of GAS5 on tumor growth in vivo was evaluated. Results: GAS5 was downregulated in human osteosarcoma tissues and cell lines. Overexpression of GAS5 could significantly suppress, and downregulation of GAS5 promoted, proliferation and invasion of osteosarcoma cells. GAS5 could directly bind with and downregulated miR-23a-3p that post-transcriptionally downregulated the tumor suppressor PTEN and positively regulated proliferation and invasion of osteosarcoma cells. Rescue experiments confirmed the involvement of miR-23a-3p and PTEN in GAS5-mediated cell behaviors by modifying the phosphatidylinositol-3-kinases/protein-serine-threonine kinase (PI3K/AKT) pathway. GAS5 could inhibit tumor growth in vivo . Conclusion: GAS5 functions as a competing endogenous RNA , sponging miR-23a-3p, to promote PTEN expression and suppress cell growth and invasion in osteosarcoma by regulating the PI3K/AKT pathway.

scholarly journals LncRNA GAS5 suppresses the proliferation and invasion of osteosarcoma cells via the miR-23a-3p/PTEN/PI3K/AKT axis

2020 ◽  
Author(s):  
Jianmin Liu ◽  
Ming Chen ◽  
Longyang Ma ◽  
Xingbo Dang ◽  
Gongliang Du
Keyword(s):  
Tumor Suppressor ◽  
Tumor Growth ◽  
Akt Pathway ◽  
Osteosarcoma Cell ◽  
Osteosarcoma Cells ◽  
Cell Behaviors ◽  
Human Osteosarcoma ◽  
Proliferation And Invasion

Abstract Background: Accumulating evidence has shown that lncRNA growth arrest special 5 (GAS5) is a well‑known tumor suppressor in the pathogenesis of a variety of human cancers. However, the detailed role of GAS5 in osteosarcoma is largely unclear. Here, we explore the role of GAS5 in progression of osteosarcoma. Methods: The expression level of GAS5 was detected in human osteosarcoma tissues and matched adjacent tissues, as well as osteosarcoma cell lines and nonmalignant osteoblast cells. Then, in vitro gain- and loss-of-function experiments, with the pcDNA-GAS5 expression vector and GAS5-siRNA, were performed in U2OS and HOS cells to determine the effect of GAS5 on osteosarcoma cell proliferation and invasion. Subsequently, we searched potential miRNA targets with bioinformatics analysis and confirmed their interaction by using luciferase reporter gene and RNA pull-down assays. The function and mechanism of miR-23a-3p in proliferation and invasion was also investigated in U2OS and HOS cells. Furthermore, rescue experiments were performed to verify the involvement of miR-23a-3p and its target gene in GAS5-mediated cell behaviors. Finally, a xenograft nude mouse model was established by subcutaneous injection with U2OS cells overexpressing GAS5 or not, and the effect of GAS5 on tumor growth in vivo was evaluated. Results: GAS5 was downregulated in human osteosarcoma tissues and cell lines. Overexpression of GAS5 could significantly suppress, and downregulation of GAS5 promoted, proliferation and invasion of osteosarcoma cells. GAS5 could directly bind with and upregulated miR-23a-3p, which post-transcriptionally downregulated the tumor suppressor PTEN and positively regulated proliferation and invasion of osteosarcoma cells. Rescue experiments confirmed the involvement of miR-23a-3p and PTEN in GAS5-mediated cell behaviors by modifying the phosphatidylinositol-3-kinases/protein-serine-threonine kinase (PI3K/AKT) pathway. GAS5 could inhibit tumor growth in vivo. Conclusion: GAS5 functions as a competing endogenous RNA, sponging miR-23a-3p, to promote PTEN expression and suppress cell growth and invasion in osteosarcoma by regulating the PI3K/AKT pathway.

HER4 promotes the growth and metastasis of osteosarcoma via the PI3K/AKT pathway

2020 ◽  
Vol 52 (4) ◽  
pp. 345-362 ◽  
Author(s):  
Xiaodong Li ◽  
Qingshan Huang ◽  
Shenglin Wang ◽  
Zhen Huang ◽  
Fengqiang Yu ◽  
...  
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Akt Pathway ◽  
Migration And Invasion ◽  
Osteosarcoma Cells ◽  
Her4 Protein

Abstract Osteosarcoma is the most common primary malignant bone tumor, which occurs in adolescents. As reported by our previous studies, HER4 indicates a poor prognosis of primary osteosarcoma. However, its mechanisms in the pathogenesis of osteosarcoma have not yet been studied. The purpose of this study was to investigate the role of HER4 in osteosarcoma and whether the PI3K/AKT pathway is involved. In this study, western blot analysis was used to investigate the expression of HER4 protein in osteosarcoma tissues and cell lines. CCK8 and transwell assays were used to detect the effects of HER4 on the proliferation, migration, and invasion of osteosarcoma cells in vitro. The effects of HER4 on the growth and metastasis of osteosarcoma in vivo were detected by tumor formation and immunofluorescence in nude mice. The role of the PI3K/AKT pathway in HER4 regulation of the growth and metastasis of osteosarcoma was examined by western blot analysis and immunofluorescence assay. We found that HER4 protein was highly expressed in clinical osteosarcoma specimens and osteosarcoma cells. HER4 markedly promoted the proliferation, migration, and invasion of osteosarcoma cells in vitro as well as the growth and metastasis of osteosarcoma in vivo. HER4 overexpression upregulated the expression of phosphorylated protein kinase B (pAKT), proliferation marker antigen Ki67, and metastasis cell marker matrix metalloproteinase 9 (MMP9). Notably, PI3K/AKT inhibitor LY294002 significantly inhibited the effects of HER4 via the downregulation of pAKT, Ki67, and MMP9. Moreover, LY294002 markedly blocked the effects of HER4-induced upregulation of tumor malignancy. The present study suggests that HER4 may promote the growth and metastasis of osteosarcoma via the PI3K/AKT pathway. The HER4/PI3K/AKT pathway could serve as a potential target for the treatment of osteosarcoma.

scholarly journals TRIP13 Activates the PI3K/AKT Signal Pathway to Promote Melanoma Progression by Interacting With FLNA

2022 ◽  
Author(s):  
Wang Lu ◽  
Zhu Mengxuan ◽  
Zhang Yong ◽  
Ren Ming ◽  
Gao Zixu ◽  
...  
Keyword(s):  
Thyroid Hormone Receptor ◽  
Tumor Development ◽  
Signal Pathway ◽  
Akt Pathway ◽  
Potential Mechanism ◽  
Skin Melanoma ◽  
The Poor ◽  
Melanoma Patients

Abstract Background: Skin melanoma is a malignant tumor originated from skin melanocytes. It is highly malignant and easy to relapse and metastasis. Finding new diagnostic and therapeutic targets has become a hot issue. Accumulating evidence now indicates that thyroid hormone receptor interactor 13 (TRIP13) plays important roles in tumor development. However, its role in melanoma remains unclear.Methods: Bioinformatic analyses were employed to excavate crucial genes in melanoma using several public databases. The expression of TRIP13 was detected by immunohistochemistry. MV3 cell and A2058 cell were steadily transfected with TRIP13 knock-down or overexpression lentiviruses, then the function and potential mechanism of TRIP13 were studied in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrum were employed to screen out the interacting molecule of TRIP13.Results: Our results showed that TRIP13 was generally upregulated in melanoma tissues and was related to the poor prognosis of melanoma patients. The overexpression of TRIP13 promotes the invasion, migration and EMT transformation of melanoma cells in vitro, and promotes lung metastasis in vivo. Mechanismly, TRIP13 interacts with FLNA, and activates the PI3K/AKT pathway, and then induces melanoma migration, invasion and EMT transformation.Conclusion: Elevated TRIP13 drives tumor progression via the FLNA/PI3K/AKT axis, and TRIP13 is a innovative prognostic molecule and potential target of targeted therapy in melanoma.

[18F]-florbetaben PET/CT Imaging in the Alzheimer’s Disease Mouse Model APPswe/PS1dE9

2018 ◽  
Vol 16 (1) ◽  
pp. 49-55 ◽  
Author(s):  
J. Stenzel ◽  
C. Rühlmann ◽  
T. Lindner ◽  
S. Polei ◽  
S. Teipel ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
New Drugs ◽  
Imaging Data ◽  
Wild Type ◽  
Preclinical Research ◽  
Standardized Uptake Values ◽  
Pet Ct

Background: Positron-emission-tomography (PET) using 18F labeled florbetaben allows noninvasive in vivo-assessment of amyloid-beta (Aβ), a pathological hallmark of Alzheimer’s disease (AD). In preclinical research, [<sup>18</sup>F]-florbetaben-PET has already been used to test the amyloid-lowering potential of new drugs, both in humans and in transgenic models of cerebral amyloidosis. The aim of this study was to characterize the spatial pattern of cerebral uptake of [<sup>18</sup>F]-florbetaben in the APPswe/ PS1dE9 mouse model of AD in comparison to histologically determined number and size of cerebral Aβ plaques. Methods: Both, APPswe/PS1dE9 and wild type mice at an age of 12 months were investigated by smallanimal PET/CT after intravenous injection of [<sup>18</sup>F]-florbetaben. High-resolution magnetic resonance imaging data were used for quantification of the PET data by volume of interest analysis. The standardized uptake values (SUVs) of [<sup>18</sup>F]-florbetaben in vivo as well as post mortem cerebral Aβ plaque load in cortex, hippocampus and cerebellum were analyzed. Results: Visual inspection and SUVs revealed an increased cerebral uptake of [<sup>18</sup>F]-florbetaben in APPswe/ PS1dE9 mice compared with wild type mice especially in the cortex, the hippocampus and the cerebellum. However, SUV ratios (SUVRs) relative to cerebellum revealed only significant differences in the hippocampus between the APPswe/PS1dE9 and wild type mice but not in cortex; this differential effect may reflect the lower plaque area in the cortex than in the hippocampus as found in the histological analysis. Conclusion: The findings suggest that histopathological characteristics of Aβ plaque size and spatial distribution can be depicted in vivo using [<sup>18</sup>F]-florbetaben in the APPswe/PS1dE9 mouse model.

scholarly journals Transcriptional Activation in Yeast Cells Lacking Transcription Factor IIA

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1573-1581 ◽  
Author(s):  
Susanna Chou ◽  
Sukalyan Chatterjee ◽  
Mark Lee ◽  
Kevin Struhl
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Large Subunit ◽  
Yeast Cells ◽  
Specific Cell ◽  
Wild Type ◽  
Activation Domains ◽  
Cycle Arrest ◽  
General Transcription Factor

Abstract The general transcription factor IIA (TFIIA) forms a complex with TFIID at the TATA promoter element, and it inhibits the function of several negative regulators of the TATA-binding protein (TBP) subunit of TFIID. Biochemical experiments suggest that TFIIA is important in the response to transcriptional activators because activation domains can interact with TFIIA, increase recruitment of TFIID and TFIIA to the promoter, and promote isomerization of the TFIID-TFIIA-TATA complex. Here, we describe a double-shut-off approach to deplete yeast cells of Toa1, the large subunit of TFIIA, to &lt;1% of the wild-type level. Interestingly, such TFIIA-depleted cells are essentially unaffected for activation by heat shock factor, Ace1, and Gal4-VP16. However, depletion of TFIIA causes a general two- to threefold decrease of transcription from most yeast promoters and a specific cell-cycle arrest at the G2-M boundary. These results indicate that transcriptional activation in vivo can occur in the absence of TFIIA.

scholarly journals Arabidopsis Disulfide Reductase, Trx-h2, Functions as an RNA Chaperone under Cold Stress

2021 ◽  
Vol 11 (15) ◽  
pp. 6865
Author(s):  
Eun Seon Lee ◽  
Joung Hun Park ◽  
Seong Dong Wi ◽  
Ho Byoung Chae ◽  
Seol Ki Paeng ◽  
...  
Keyword(s):  
Cold Stress ◽  
Wild Type ◽  
Rna Chaperone ◽  
E Coli ◽  
Cold Sensitive ◽  
Thioredoxin H ◽  
Functional Rnas

The thioredoxin-h (Trx-h) family of Arabidopsis thaliana comprises cytosolic disulfide reductases. However, the physiological function of Trx-h2, which contains an additional 19 amino acids at its N-terminus, remains unclear. In this study, we investigated the molecular function of Trx-h2 both in vitro and in vivo and found that Arabidopsis Trx-h2 overexpression (Trx-h2OE) lines showed significantly longer roots than wild-type plants under cold stress. Therefore, we further investigated the role of Trx-h2 under cold stress. Our results revealed that Trx-h2 functions as an RNA chaperone by melting misfolded and non-functional RNAs, and by facilitating their correct folding into active forms with native conformation. We showed that Trx-h2 binds to and efficiently melts nucleic acids (ssDNA, dsDNA, and RNA), and facilitates the export of mRNAs from the nucleus to the cytoplasm under cold stress. Moreover, overexpression of Trx-h2 increased the survival rate of the cold-sensitive E. coli BX04 cells under low temperature. Thus, our data show that Trx-h2 performs function as an RNA chaperone under cold stress, thus increasing plant cold tolerance.

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