scholarly journals Protein synthesis inhibitors stimulate MondoA transcriptional activity by driving an accumulation of glucose 6-phosphate

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Blake R. Wilde ◽  
Mohan R. Kaadige ◽  
Katrin P. Guillen ◽  
Andrew Butterfield ◽  
Bryan E. Welm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Synthesis ◽  
Cell Lines ◽  
Cellular Response ◽  
Transcriptional Activity ◽  
Critical Role ◽  
Negative Regulator ◽  
Protein Synthesis Inhibitors ◽  
Voltage Dependent Anion Channel ◽  
Glycolytic Intermediate

Abstract Background Protein synthesis is regulated by the availability of amino acids, the engagement of growth factor signaling pathways, and adenosine triphosphate (ATP) levels sufficient to support translation. Crosstalk between these inputs is extensive, yet other regulatory mechanisms remain to be characterized. For example, the translation initiation inhibitor rocaglamide A (RocA) induces thioredoxin-interacting protein (TXNIP). TXNIP is a negative regulator of glucose uptake; thus, its induction by RocA links translation to the availability of glucose. MondoA is the principal regulator of glucose-induced transcription, and its activity is triggered by the glycolytic intermediate, glucose 6-phosphate (G6P). MondoA responds to G6P generated by cytoplasmic glucose and mitochondrial ATP (mtATP), suggesting a critical role in the cellular response to these energy sources. TXNIP expression is entirely dependent on MondoA; therefore, we investigated how protein synthesis inhibitors impact its transcriptional activity. Methods We investigated how translation regulates MondoA activity using cell line models and loss-of-function approaches. We examined how protein synthesis inhibitors effect gene expression and metabolism using RNA-sequencing and metabolomics, respectively. The biological impact of RocA was evaluated using cell lines and patient-derived xenograft organoid (PDxO) models. Results We discovered that multiple protein synthesis inhibitors, including RocA, increase TXNIP expression in a manner that depends on MondoA, a functional electron transport chain and mtATP synthesis. Furthermore, RocA and cycloheximide increase mtATP and G6P levels, respectively, and TXNIP induction depends on interactions between the voltage-dependent anion channel (VDAC) and hexokinase (HK), which generates G6P. RocA treatment impacts the regulation of ~ 1200 genes, and ~ 250 of those genes are MondoA-dependent. RocA treatment is cytotoxic to triple negative breast cancer (TNBC) cell lines and shows preferential cytotoxicity against estrogen receptor negative (ER−) PDxO breast cancer models. Finally, RocA-driven cytotoxicity is partially dependent on MondoA or TXNIP. Conclusions Our data suggest that protein synthesis inhibitors rewire metabolism, resulting in an increase in mtATP and G6P, the latter driving MondoA-dependent transcriptional activity. Further, MondoA is a critical component of the cellular transcriptional response to RocA. Our functional assays suggest that RocA or similar translation inhibitors may show efficacy against ER− breast tumors and that the levels of MondoA and TXNIP should be considered when exploring these potential treatment options.

scholarly journals Protein synthesis inhibitors stimulate MondoA transcriptional activity by driving an accumulation of glucose 6-phosphate

2020 ◽  
Author(s):  
Blake R Wilde ◽  
Mohan R Kaadige ◽  
Katrin P Guillen ◽  
Andrew Butterfield ◽  
Bryan E Welm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Synthesis ◽  
Cell Lines ◽  
Transcriptional Activity ◽  
Critical Role ◽  
Negative Regulator ◽  
Breast Cancer Cell Lines ◽  
Protein Synthesis Inhibitors ◽  
Voltage Dependent Anion Channel ◽  
Glycolytic Intermediate

Abstract BACKGROUND Protein synthesis is regulated by the availability of amino acids, the engagement of growth factor signaling pathways and ATP levels sufficient to support translation. Crosstalk between these inputs is extensive, yet other regulatory mechanisms remain to be characterized. For example, the translation initiation inhibitor Rocaglamide A (RocA) induces Thioredoxin Interacting Protein (TXNIP). TXNIP is a negative regulator of glucose uptake, thus its induction by RocA links translation to the availability of glucose. MondoA is the principal regulator of glucose-induced transcription and its activity is triggered by the glycolytic intermediate, glucose 6-phosphate (G6P). MondoA responds to G6P generated by cytoplasmic glucose and mitochondrial ATP (mtATP), suggesting a critical role in the cellular response to these energy sources. TXNIP expression is entirely dependent on MondoA, therefore, we investigated how protein synthesis inhibitors impact its transcriptional activity.METHODS We investigated how translation regulates MondoA activity using cell line models and loss-of-function approaches. We examined how protein synthesis inhibitors effect gene expression and metabolism using RNA-sequencing and metabolomics, respectively. The biological impact of RocA was evaluated using cell lines and Patient-Derived xenograft Organoid (PDxO) models. RESULTS We discovered that multiple protein synthesis inhibitors, including RocA, increase TXNIP expression in a manner that depends on MondoA, a functional electron transport chain and mtATP synthesis. Furthermore, RocA increases mtATP and G6P levels and TXNIP induction depends on interactions between the Voltage-Dependent Anion Channel (VDAC) and hexokinase, which generates G6P. RocA treatment impacts the regulation of ~1200 genes and ~250 of those genes are MondoA-dependent. RocA treatment is cytotoxic to Triple Negative Breast Cancer cell lines and shows preferential cytotoxicity against ER- PDxO breast cancer models. Finally, RocA-driven cytotoxicity is partially-dependent on MondoA or TXNIP.CONCLUSIONS Our data suggest that protein synthesis inhibitors rewire metabolism, resulting in an increase in mtATP and G6P, the latter driving MondoA-dependent transcriptional activity. Further, MondoA is a critical component of the cellular transcriptional response to RocA. Our functional assays suggest that RocA or similar translation inhibitors may show efficacy against ER- breast tumors and that the levels of MondoA and TXNIP should be considered when exploring these potential treatment options.

scholarly journals Protein synthesis inhibitors stimulate MondoA transcriptional activity by driving an accumulation of glucose 6-phosphate

2020 ◽  
Author(s):  
Blake R Wilde ◽  
Mohan R Kaadige ◽  
Katrin P Guillen ◽  
Andrew Butterfield ◽  
Bryan E Welm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Synthesis ◽  
Cell Lines ◽  
Transcriptional Activity ◽  
Critical Role ◽  
Negative Regulator ◽  
Breast Cancer Cell Lines ◽  
Protein Synthesis Inhibitors ◽  
Voltage Dependent Anion Channel ◽  
Glycolytic Intermediate

Abstract BACKGROUND Protein synthesis is regulated by the availability of amino acids, the engagement of growth factor signaling pathways and ATP levels sufficient to support translation. Crosstalk between these inputs is extensive, yet other regulatory mechanisms remain to be characterized. For example, the translation initiation inhibitor Rocaglamide A (RocA) induces Thioredoxin Interacting Protein (TXNIP). TXNIP is a negative regulator of glucose uptake, thus its induction by RocA links translation to the availability of glucose. MondoA is the principal regulator of glucose-induced transcription and its activity is triggered by the glycolytic intermediate, glucose 6-phosphate (G6P). MondoA responds to G6P generated by cytoplasmic glucose and mitochondrial ATP (mtATP), suggesting a critical role in the cellular response to these energy sources. TXNIP expression is entirely dependent on MondoA, therefore, we investigated how protein synthesis inhibitors impact its transcriptional activity. METHODS We investigated how translation regulates MondoA activity using cell line models and loss-of-function approaches. We examined how protein synthesis inhibitors effect gene expression and metabolism using RNA-sequencing and metabolomics, respectively. The biological impact of RocA was evaluated using cell lines and Patient-Derived xenograft Organoid (PDxO) models. RESULTS We discovered that multiple protein synthesis inhibitors, including RocA, increase TXNIP expression in a manner that depends on MondoA, a functional electron transport chain and mtATP synthesis. Furthermore, RocA increases mtATP and G6P levels and TXNIP induction depends on interactions between the Voltage-Dependent Anion Channel (VDAC) and hexokinase, which generates G6P. RocA treatment impacts the regulation of ~1200 genes and ~250 of those genes are MondoA-dependent. RocA treatment is cytotoxic to Triple Negative Breast Cancer cell lines and shows preferential cytotoxicity against ER- PDxO breast cancer models. Finally, RocA-driven cytotoxicity is partially-dependent on MondoA or TXNIP. CONCLUSIONS Our data suggest that protein synthesis inhibitors rewire metabolism, resulting in an increase in mtATP and G6P, the latter driving MondoA-dependent transcriptional activity. Further, MondoA is a critical component of the cellular transcriptional response to RocA. Our functional assays suggest that RocA or similar translation inhibitors may show efficacy against ER- breast tumors and that the levels of MondoA and TXNIP should be considered when exploring these potential treatment options.

scholarly journals Long non-coding RNA ARHGAP5-AS1 inhibits migration of breast cancer cell via stabilizing SMAD7 protein

2021 ◽  
Author(s):  
Chen-Long Wang ◽  
Jing-Chi Li ◽  
Ci-Xiang Zhou ◽  
Cheng-Ning Ma ◽  
Di-Fei Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Rho Gtpase ◽  
Critical Role ◽  
Luciferase Reporter ◽  
Breast Cancer Cell Lines ◽  
Smad7 Protein

Abstract Purpose Tumor metastasis is the main cause of death from breast cancer patients and cell migration plays a critical role in cancer metastasis. Recent studies have shown long non-coding RNAs (lncRNAs) play an essential role in the initiation and progression of cancer. In the present study, the role of an LncRNA, Rho GTPase Activating Protein 5- Antisense 1 (ARHGAP5-AS1) in breast cancer was investigated. Methods RNA sequencing was performed to find out dysregulated LncRNAs in MDA-MB-231-LM2 cells. Transwell migration assays and F-actin staining were utilized to estimate cell migration ability. RNA pulldown assays and RNA immunoprecipitation were used to prove the interaction between ARHGAP5-AS1 and SMAD7. Western blot and immunofluorescence imaging were used to examine the protein levels. Dual luciferase reporter assays were performed to evaluate the activation of TGF-β signaling. Results We analyzed the RNA-seq data of MDA-MB-231 and its highly metastatic derivative MDA-MB-231-LM2 cell lines (referred to as LM2) and identified a novel lncRNA (NR_027263) named as ARHGAP5-AS1, which expression was significantly downregulated in LM2 cells. Further functional investigation showed ARHGAP5-AS1 could inhibit cell migration via suppression of stress fibers in breast cancer cell lines. Afterwards, SMAD7 was further identified to interact with ARHGAP5-AS1 by its PY motif and thus its ubiquitination and degradation was blocked due to reduced interaction with E3 ligase SMURF1 and SMURF2. Moreover, ARHGAP5-AS1 could inhibit TGF-β signaling pathway due to its inhibitory role on SMAD7. Conclusion ARHGAP5-AS1 inhibits breast cancer cell migration via stabilization of SMAD7 protein and could serve as a novel biomarker and a potential target for breast cancer in the future.

scholarly journals The Molecular Pharmacology of Pateamine A

2021 ◽  
Author(s):  
◽  
James Henry Matthews
Keyword(s):  
Protein Synthesis ◽  
Cell Lines ◽  
Mammalian Cell ◽  
Mode Of Action ◽  
Protein Synthesis Inhibitors ◽  
Primary Target ◽  
Dead Box ◽  
Mammalian Cell Lines ◽  
Pateamine A

<p>Pateamine A is a cytotoxic terpenoid isolated from the marine sponge Mycale hentscheli that induces apoptosis in mammalian cell lines and is growth inhibitory to yeasts and fungi, yet shows no inhibitory action in prokaryotes. The targets of pateamine in mammalian cell lines were isolated and identified using a combination of affinity chromatography and mass spectrometry, putative targets included the DEAD-Box helicase eIF4A family of proteins, β-tubulin and actin. In vitro assessment of tubulin and actin polymerization showed pateamine was able to affect them only at high micromolar concentrations, whereas the effect on eIF4A in vitro was shown by others to occur at nanomolar concentrations. Additionally, pateamine was shown to inhibit cap-dependent protein synthesis in vivo, suggesting eIF4A as a primary target. The generation of a pateamine resistance-conferring mutation in the yeast eIF4A encoding gene TIF1, suggested further that eIF4A is a primary target in both mammalian and yeast cells, and allows the speculation of the position of the binding site for pateamine on the N-terminal lobe of eIF4A and the proposal of potential covalent interaction between this drug and its target. Given the size of the DEAD-Box helicase family, all of which share considerable homology with the eIF4As, FAL1 especially which is essential for rRNA maturation, a chemogenomic screen was performed in an attempt to establish the breadth of functional interactions of pateamine. The results of hierarchical clustering of these screen results suggest that pateamine has a mode-of-action distinct from other compounds screened previously, despite its effect on protein synthesis it failed to cluster with any other protein synthesis inhibitors regardless of their separate mechanisms, though, as a class, protein synthesis inhibitors were not found to form a discrete cluster in any of the variations of cluster analysis performed. Functional analysis, by GO term enrichment, of the genes whose deletions are hypersensitive to pateamine indicates that deletions of genes involved in numerous aspects of RNA metabolism affect pateamine sensitivity, however clear results regarding the involvement of FAL1 or any other non-eIF4A target in pateamine’s mode-of-action were not found.</p>

scholarly journals Development of Nimesulide Analogues as Dual Tubulin and HSP27 Inhibitor for Treating Female Cancers

2020 ◽  
Author(s):  
Laila Jarragh Alhadad ◽  
Fars Alanazi ◽  
Gamaleldin Harisa
Keyword(s):  
Breast Cancer ◽  
Ovarian Cancer ◽  
Cell Lines ◽  
Biological Activities ◽  
Critical Role ◽  
Biological Evaluation ◽  
Crystallographic Analysis ◽  
Skbr3 Cell ◽  
Chemical Structures ◽  
Ic50 Values

Tubulin and heat shock protein 27 (HSP27) are up-regulated in cancer cells, and play a critical role in cell division, and proliferation. Therefore, they are targets for discovery of anticancer therapy. The objective of this study is to design, characterize, and biologically evaluate the nimesulide analogues to combat female cancer such as ovarian cancer, and breast cancer. Herein, the nimesulide analogues are designed to target both tubulin and HSP27 functions. Ovarian cancer (SKOV3) and breast cancer (SKBR3) cell lines were used as surrogate models to test the nimesulide analogs biological activities using MTT assay. In the present study, four nimesulide analogues were designed, synthesized and the chemical structures were with the biological evaluation were studied. The synthesized agents were characterized by 1H-NMR, 13C-NMR, the molecular weight was confirmed using GC-MS technique, and melting point. Besides, the agent L4 structure was confirmed using X-ray crystallographic analysis. The present data revealed that nimesulide analogs have potent anticancer activity against SKOV3and SKBR3 cell lines. The IC50 values for both SKOV3 and SKBR3 cell lines treated with the agents showed a potent cell growth inhibition range of 0.23-2.02 &micro;M and 0.50-3.73 &micro;M respectively. In conclusion, the designed nimesulide analogues can target both tubulins, and HSP27 concurrently, and they are promising agents as future chemotherapy female cancers.

Effects of mycoplasma contamination on phenotypic expression of mitochondrial mutants in human cells

1981 ◽  
Vol 1 (4) ◽  
pp. 321-329
Author(s):  
C J Doersen ◽  
E J Stanbridge
Keyword(s):  
Protein Synthesis ◽  
Infected Cell ◽  
Cell Lines ◽  
Resistant Strain ◽  
Drug Sensitivity ◽  
Mitochondrial Protein ◽  
Phenotypic Expression ◽  
Mitochondrial Protein Synthesis ◽  
Protein Synthesis Inhibitors

HeLa cells sensitive to the mitochondrial protein synthesis inhibitors erythromycin (ERY) and chloramphenicol (CAP) and HeLa variants resistant to the effects of these drugs were purposefully infected with drug-sensitive and -resistant mycoplasma strains. Mycoplasma hyorhinis and the ERY-resistant strain of Mycoplasma orale, MO-ERYr, did not influence the growth of HeLa and ERY-resistant ERY2301 cells in the presence or absence of ERY. M. hyorhinis also did not affect the growth of HeLa and CAP-resistant Cap-2 cells in the presence or absence of CAP. However, both HeLa and Cap-2 cells infected with the CAP-resistant strain of M. hyorhinis, MH-CAPr, were more sensitive to the cytotoxic effect of CAP. This may be due to the glucose dependence of the cells, which was compromised by the increased utilization of glucose by MH-CAPr in these infected cell cultures. In vitro protein synthesis by isolated mitochondria was significantly altered by mycoplasma infection of the various cell lines. A substantial number of mycoplasmas copurified with the mitochondria, resulting in up to a sevenfold increase in the incorporation of [3H]leucine into the trichloroacetic acid-insoluble material. More importantly, the apparent drug sensitivity or resistance of mitochondrial preparations from mycoplasma-infected cells reflected the drug sensitivity or resistance of the contaminating mycoplasmas. These results illustrate the hazards in interpreting mitochondrial protein synthesis data derived from mycoplasma-infected cell lines, particularly putative mitochondrially encoded mutants resistant to inhibitors of mitochondrial protein synthesis.

scholarly journals Loss of USF transcriptional activity in breast cancer cell lines

Oncogene ◽  
1999 ◽  
Vol 18 (40) ◽  
pp. 5582-5591 ◽  
Author(s):  
Preeti M Ismail ◽  
Tao Lu ◽  
Michèle Sawadogo
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Transcriptional Activity ◽  
Cancer Cell Lines ◽  
Breast Cancer Cell Lines

SOCS-1, a negative regulator of cytokine signaling, is frequently silenced by methylation in multiple myeloma

Blood ◽  
2003 ◽  
Vol 101 (7) ◽  
pp. 2784-2788 ◽  
Author(s):  
Oliver Galm ◽  
Hirohide Yoshikawa ◽  
Manel Esteller ◽  
Rainhardt Osieka ◽  
James G. Herman
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Transcriptional Activation ◽  
Bone Marrow Cells ◽  
Cpg Island ◽  
Critical Role ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Cytokine Signaling ◽  
Normal Peripheral Blood

The suppressor of cytokine signaling (SOCS) family of proteins has been implicated in the negative regulation of several cytokine pathways, particularly the receptor-associated tyrosine kinase/signal transducer and activator of transcription (Jak/STAT) pathways of transcriptional activation. SOCS-1 (also known as JAB and SSI-1) inhibits signaling by many cytokines. Because of the previously observed hypermethylation-associated inactivation of SOCS-1in hepatocellular carcinoma and the critical role of interleukin-6 (IL-6) as a survival factor in multiple myeloma (MM), we examined CpG island methylation of the SOCS-1 gene in MM cell lines and primary MM samples. Aberrant SOCS-1methylation was found in the IL-6–dependent MM cell lines U266 and XG1, which correlated with transcriptional silencing. Treatment of these cell lines with the demethylating agent 5-aza-2′-deoxycytidine (DAC) up-regulated SOCS-1 expression. Methylation-associated inactivation of SOCS-1 in hematopoietic cell lines correlated with greater sensitivity to the chemical JAK inhibitor AG490. Using methylation-specific polymerase chain reaction (MSP), we found that SOCS-1 is hypermethylated in 62.9% (23/35) of MM patient samples. In contrast, methylation analysis of malignant lymphomas of various histologies revealed SOCS-1 hypermethylation in only 3.2% (2/62), and there was no methylation of SOCS-1 in normal peripheral blood leukocytes or bone marrow cells. We conclude thatSOCS-1 is frequently inactivated by hypermethylation in MM patients. Silencing of the SOCS-1 gene may impair negative regulation of the Jak/STAT pathway and therefore result in greater responsiveness to cytokines, thus supporting survival and expansion of MM cells.

scholarly journals Models and mechanisms of acquired antihormone resistance in breast cancer: significant clinical progress despite limitations

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
Elizabeth E. Sweeney ◽  
Russell E. McDaniel ◽  
Philipp Y. Maximov ◽  
Ping Fan ◽  
V. Craig Jordan
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Tumor Regression ◽  
Critical Role ◽  
Evolutionary Process ◽  
Cancer Cell Line ◽  
Treatment And Prevention ◽  
Er Positive ◽  
Mcf 7

AbstractTranslational research for the treatment and prevention of breast cancer depends upon the four Ms: models, molecules, and mechanisms in order to create medicines. The process, to target the estrogen receptor (ER) in estrogen-dependent breast cancer, has yielded significant advances in patient survivorship and the first approved medicines (tamoxifen and raloxifene) to reduce the incidence of any cancer in high- or low-risk women. This review focuses on the critical role of the few ER-positive cell lines (MCF-7, T47D, BT474, ZR-75-1) that continue to advance our understanding of the estrogen-regulated biology of breast cancer. More importantly, the model cell lines have provided an opportunity to document the development and evolution of acquired antihormone resistance. The description of this evolutionary process that occurs in micrometastatic disease during up to a decade of adjuvant therapy would not be possible in the patient. The use of the MCF-7 breast cancer cell line, in particular, has been instrumental in discovering a vulnerability of ER-positive breast cancer exhaustively treated with antihormone therapy. Physiologic estradiol acts as an apoptotic trigger to cause tumor regression. These unanticipated findings in the laboratory have translated to clinical advances in our knowledge of the paradoxical role of estrogen in the life and death of breast cancer.

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