scholarly journals EXTH-35. SYNERGISTIC EFFECT OF TARGETING THIOREDOXIN REDUCTASE (TRX1) AND DEPLETION OF GLUTATHIONE SYSTEM (GSH) IN GLIOBLASTOMA STEM CELLS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii94-ii94
Author(s):  
Fatemeh Jamali ◽  
Paul Daniel ◽  
Kevin Petrecca ◽  
Bassam Abdulkarim ◽  
Siham Sabri
Keyword(s):  
Stem Cells ◽  
Dna Methyltransferase ◽  
Thioredoxin Reductase ◽  
Redox System ◽  
Redox Balance ◽  
Suppressor Gene ◽  
Irreversible Inhibitor ◽  
Drug Induced ◽  
Cytotoxic Effects

Abstract Glioblastoma (GBM), the most common and advanced malignant primary brain tumor in adults remains incurable. GBM tumor recurrence occurs within a short time reflecting the failure to eradicate chemo-radioresistant GBM stem cells (GSCs). GSCs alter the redox system including Thioredoxin (Trx) and glutathione (GSH) systems to counteract increased reactive oxygen species (ROS). We previously showed the role of O6-methylguanine-DNA methyltransferase (MGMT) in response to PRIMAMET, a drug that targets the TP53 tumor suppressor gene and decrease Thioredoxin reductase1 (TRxR1) levels and further identified a positive relationship between MGMT and TrxR1 in established GBM cell lines isogenic for MGMT. Auranofin (Au), an orally available ROS-inducing FDA-approved drug is a potent irreversible inhibitor of TrxR1. The effect of Au on GSCs and the potential relationship between TrXR1, MGMT and p53 specifically in GSCs remain unknown. We hypothesized that increased ROS levels in GSCs might affect their drug resistant phenotype. we investigated the cytotoxic effects of Au on GSCs with known MGMT and P53 status and the mechanisms underlying these effects. Our results suggest that Au exerts strong cytotoxic effects in GSCs within a micromolar range. These effects were associated with increased ROS levels, decreased TrXR1, MGMT, phosphorylation of ERk1/2, activation of p53 and increased apoptosis, we also used a knockdown strategy to assess the role of p53 and showed that increased sensitivity to Au for p53-knockdown. We showed the role of ROS in response to Au using ROS inducer L-Buthionine Sulfoxamine (L-BSO), a GSH inhibitor, and ROS scavenger N-Acetylcysteine (NAc). L-BSO combined with Au drastically decreased the IC50 within a nanomolar range suggesting the crucial role of both Trx and GSH systems in GSCs redox balance. Increased ROS with concomitant GSH depletion using L-BSO might circumvent drug-induced oxidative stress and overcome drug resistance in MGMT-positive and negative GSCs

scholarly journals The Effects of Lycopene on the Methylation of the GSTP1 Promoter and Global Methylation in Prostatic Cancer Cell Lines PC3 and LNCaP

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Li-Juan Fu ◽  
Yu-Bin Ding ◽  
Lan-Xiang Wu ◽  
Chun-Jie Wen ◽  
Qiang Qu ◽  
...  
Keyword(s):  
Cell Line ◽  
Dna Methyltransferase ◽  
Suppressor Gene ◽  
In Vivo Studies ◽  
Global Methylation ◽  
Protein Levels ◽  
Long Interspersed Element ◽  
Androgen Independent

DNA (cytosine-5-) methylation silencing of GSTP1 function occurs in prostate adenocarcinoma (PCa). Previous studies have shown that there is an inverse relationship between dietary lycopene intake and the risk of PCa. However, it is unknown whether lycopene reactivates the tumor suppressor gene glutathioneS-transferase-π(GSTP1) by demethylation of the hypermethylated CpGs that act to silence the GSTP1 promoter. Here, we demonstrated that lycopene treatment significantly decreased the methylation levels of the GSTP1 promoter and increased the mRNA and protein levels of GSTP1 in an androgen-independent PC-3 cell line. In contrast, lycopene treatment did not demethylate the GSTP1 promoter or increase GSTP1 expression in the androgen-dependent LNCaP cell line. DNA methyltransferase (DNMT) 3A protein levels were downregulated in PC-3 cells following lycopene treatment; however, DNMT1 and DNMT3B levels were unchanged. Furthermore, the long interspersed element (LINE-1) and short interspersed element ALU were not demethylated when treated by lycopene. In LNCaP cells, lycopene treatment did not affect any detected DNMT protein expression, and the methylation levels of LINE-1 and ALU were decreased. These results indicated that the protective effect of lycopene on the prostate is different between androgen-dependent and androgen-independent derived PCa cells. Further, in vivo studies should be conducted to confirm these promising results and to evaluate the potential role of lycopene in the protection of the prostate.

scholarly journals Potential Role of GST-π in Lung Cancer Stem Cell Cisplatin Resistance

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenjun Wang ◽  
Jianping Wei ◽  
Xiaoyun Tu ◽  
Xiaoqun Ye
Keyword(s):  
Lung Cancer ◽  
Stem Cells ◽  
Protein Expression ◽  
A549 Cell ◽  
Potential Role ◽  
Redox Balance ◽  
Adherent Cells ◽  
Cellular Redox ◽  
Intracellular Ros

Background. Cancer stem cells (CSCs) are responsible for tumorigenesis, chemoresistance, and metastasis. Chemoresistance is a major challenge in the management of lung cancer. Glutathione-sulphur-transferase-π (GST-π) plays an important role in the origin and development of various types of cancer by regulating the cellular redox balance. Recent investigations have demonstrated that GST-π is associated with the chemoresistance of lung CSCs (LCSCs). However, the mechanism of GST-π in lung cancer, particularly in LCSCs, remains unclear. The present study is aimed at exploring the potential role of GST-π in stemness and cisplatin (DDP) resistance of LCSCs. Materials and methods. In the present study, lung cancer cell spheres were established using the A549 cell line, which according to our previous research, was confirmed to exhibit characteristics of stem cells. Next, GST-π protein expression, apoptosis percentage, and intracellular reactive oxygen species (ROS) concentration in A549 adherent cells and A549 cell spheres were analyzed by western blotting and flow cytometry, respectively. Finally, DDP resistance, ROS concentration, and GST-π expression in LCSCs were analyzed following the interference with GST-π using DL-buthionine-(S,R)-sulphoximine and N-acetylcysteine. Results. The results revealed that GST-π was highly expressed in A549 cell spheres compared with A549 adherent cells and was associated with a decreased intracellular ROS concentration (both P < 0.05 ). Regulating GST-π protein expression could alter DDP resistance of LCSCs by influencing ROS. Conclusion. These results suggested that GST-π may be important for LCSC drug resistance by downregulating ROS levels. These findings may contribute to the development of new adjuvant therapeutic strategies for lung cancer.

Stroma cells and Monocytes make Multiple Myeloma Cells Active In Bone Marrow Microenviroment

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5333-5333
Author(s):  
Hiroshi Ikeda ◽  
Tadao Ishida ◽  
Toshiaki Hayashi ◽  
Yuka Aoki ◽  
Yasuhisa Shinomura
Keyword(s):  
Stem Cells ◽  
Multiple Myeloma ◽  
Bone Marrow ◽  
Cell Lines ◽  
Stromal Cells ◽  
Conflicts Of Interest ◽  
Cell Contact ◽  
Drug Induced ◽  
Myeloma Cells

Abstract The Bone marrow (BM) microenvironment plays crucial role in pathogenesis of multiple myeloma　(MM). Paracrine secretion of cytokines in BM stromal cells promotes multiple myeloma cell proliferation and protects against drug-induced cytotoxicity. In current study, monocytes, component of BM cells, can directly promote mesenchymal stem cells osteogenic differentiation through cell contact interactions. Down-regulation of inhibitors such as DKK1 drives the differentiation of mesechymal stem cells into osteoblasts. In this study, we examined the role of monocytes as a potential niche component that supports myeloma cells. We investigated the proliferation of MM cell lines cultured alone or co-cultured with BM stromal cells, monocytes, or a combination of BM stromal cells and monocytes. Consistently, we observed increased proliferation of MM cell lines in the presence of either BM stromal cells or monocytes compared to cell line-only control. Furthermore, the co-culture of BM stromal cells plus monocytes induced the greatest degree of proliferation of myeloma cells. In addition to increased proliferation, BMSCs and monocytes decreased the rate of apoptosis of myeloma cells. Our results therefore suggest that highlights the role of monocyte as an important component of the BM microenvironment. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Thymoquinone and Difluoromethylornithine (DFMO) Synergistically Induce Apoptosis of Human Acute T Lymphoblastic Leukemia Jurkat Cells Through the Modulation of Epigenetic Pathways

2020 ◽  
Vol 19 ◽  
pp. 153303382094748
Author(s):  
Mahmoud Alhosin ◽  
Syed Shoeb I. Razvi ◽  
Ryan A. Sheikh ◽  
Jalaluddin A. Khan ◽  
Mazin A. Zamzami ◽  
...  
Keyword(s):  
Cell Viability ◽  
Dna Methyltransferase ◽  
Synergistic Effects ◽  
Lymphoblastic Leukemia ◽  
Ring Finger ◽  
Jurkat Cells ◽  
Irreversible Inhibitor ◽  
Cytotoxic Effects ◽  
Histone Deacetylase 1 ◽  
Underlying Mechanisms

Thymoquinone (TQ), a natural anticancer agent exerts cytotoxic effects on several tumors by targeting multiple pathways, including apoptosis. Difluoromethylornithine (DFMO), an irreversible inhibitor of the ornithine decarboxylase (ODC) enzyme, has shown promising inhibitory activities in many cancers including leukemia by decreasing the biosynthesis of the intracellular polyamines. The present study aimed to investigate the combinatorial cytotoxic effects of TQ and DFMO on human acute T lymphoblastic leukemia Jurkat cells and to determine the underlying mechanisms. Here, we show that the combination of DFMO and TQ significantly reduced cell viability and resulted in significant synergistic effects on apoptosis when compared to either DFMO or TQ alone. RNA-sequencing showed that many key epigenetic players including Ubiquitin-like containing PHD and Ring finger 1 (UHRF1) and its 2 partners DNA methyltransferase 1 (DNMT1) and histone deacetylase 1 (HDAC1) were down-regulated in DFMO-treated Jurkat cells. The combination of DFMO and TQ dramatically decreased the expression of UHRF1, DNMT1 and HDAC1 genes compared to either DFMO or TQ alone. UHRF1 knockdown led to a decrease in Jurkat cell viability. In conclusion, these results suggest that the combination of DFMO and TQ could be a promising new strategy for the treatment of human acute T lymphoblastic leukemia by targeting the epigenetic code.

scholarly journals miRNA-mediated loss of m6A increases nascent translation in glioblastoma

2020 ◽  
Author(s):  
John P. Zepecki ◽  
David Karambizi ◽  
J. Eduardo Fajardo ◽  
Kristin M. Snyder ◽  
Charlotte Guetta-Terrier ◽  
...  
Keyword(s):  
Stem Cells ◽  
Critical Role ◽  
Ectopic Expression ◽  
Stem Cell Differentiation ◽  
Protein Translation ◽  
Suppressor Gene ◽  
Ribosome Profiling ◽  
Human Glioblastoma ◽  
Glioblastoma Stem Cell

AbstractWithin the glioblastoma cellular niche, glioma stem cells (GSCs) can give rise to differentiated glioma cells (DGCs) and, when necessary, DGCs can reciprocally give rise to GSCs to maintain the cellular equilibrium necessary for optimal tumor growth. Here, using ribosome profiling, transcriptome and m6A RNA sequencing, we show that GSCs from patients with different subtypes of glioblastoma share a set of transcripts, which exhibit a pattern of m6A loss and increased protein translation during differentiation. The target sequences of a group of miRNAs overlap the canonical RRACH m6A motifs of these transcripts, many of which confer a survival advantage in glioblastoma. Ectopic expression of the RRACH-binding miR-145 induces loss of m6A, formation of FTO/AGO1/ILF3/miR-145 complexes on a clinically relevant tumor suppressor gene (CLIP3) and significant increase in its nascent translation. Inhibition of miR-145 maintains RRACH m6A levels of CLIP3 and inhibits its nascent translation. This study highlights a critical role of miRNAs in assembling complexes for m6A demethylation and induction of protein translation during GSC state transition.Author SummaryCellular plasticity and epigenetic adaptation of human glioblastoma stem cells to the tumor microenvironment is a hallmark of this devastating disease. With our present work, we discover the relationship between miRNAs and the RNA methylation machinery in human glioblastoma and show how miRNA-induced loss of m6A results in increase in protein translation of clinically important transcripts during glioblastoma stem cell differentiation. Leveraging the dynamic functions of these miRNAs can be important in the design of optimal therapeutics targeted at cancer cell plasticity.

scholarly journals The biologic properties of leukemias arising from BCR/ABL-mediated transformation vary as a function of developmental origin and activity of the p19ARF gene

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4184-4192 ◽  
Author(s):  
Pin-Yi Wang ◽  
Fay Young ◽  
Chun-Yu Chen ◽  
Brett M. Stevens ◽  
Sarah J. Neering ◽  
...  
Keyword(s):  
Stem Cells ◽  
Lymphoblastic Leukemia ◽  
Suppressor Gene ◽  
Functional Difference ◽  
Tumor Initiating Cells ◽  
Hematopoietic Stem ◽  
Oncogenic Mutations ◽  
Background Expression ◽  
Unique Mechanism

Abstract Recent reports have shown that upon expression of appropriate oncogenes, both stem cells and more differentiated progenitor populations can serve as leukemia-initiating cells. These studies suggest that oncogenic mutations subvert normal development and induce reacquisition of stem-like features. However, no study has described how specific mutations influence the ability of differentiating cell subsets to serve as leukemia-initiating cells and if varying such cellular origins confers a functional difference. We have examined the role of the tumor suppressor gene p19ARF in a murine model of acute lymphoblastic leukemia and found that loss of p19ARF changes the spectrum of cells capable of tumor initiation. With intact p19ARF, only hematopoietic stem cells (HSCs) can be directly transformed by BCR/ABL expression. In a p19ARF-null genetic background expression of the BCR/ABL fusion protein renders functionally defined HSCs, common lymphoid progenitors (CLP), and precursor B-lymphocytes competent to generate leukemia stem cells. Furthermore, we show that leukemias arising from p19ARF-null HSC versus pro-B cells differ biologically, including relative response to drug insult. Our observations elucidate a unique mechanism by which heterogeneity arises in tumor populations harboring identical genetic lesions and show that activity of p19ARF profoundly influences the nature of tumor-initiating cells during BCR/ABL-mediated leukemogenesis.

scholarly journals Intracellular Redox-Balance Involvement in Temozolomide Resistance-Related Molecular Mechanisms in Glioblastoma

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1315 ◽  
Author(s):  
Alessia Lo Dico ◽  
Daniela Salvatore ◽  
Cristina Martelli ◽  
Dario Ronchi ◽  
Cecilia Diceglie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanisms ◽  
Redox Balance ◽  
Oxygen Species ◽  
Cytotoxic Effects ◽  
Mitochondrial Ros ◽  
Resistance Fluctuations ◽  
First Time ◽  
Chaperone Mediated Autophagy

Glioblastoma (GBM) is the most common astrocytic-derived brain tumor in adults, characterized by a poor prognosis mainly due to the resistance to the available therapy. The study of mitochondria-derived oxidative stress, and of the biological events that orbit around it, might help in the comprehension of the molecular mechanisms at the base of GBM responsiveness to Temozolomide (TMZ). Sensitive and resistant GBM cells were used to test the role of mitochondrial ROS release in TMZ-resistance. Chaperone-Mediated Autophagy (CMA) activation in relation to reactive oxygen species (ROS) release has been measured by monitoring the expression of specific genes. Treatments with H2O2 were used to test their potential in reverting resistance. Fluctuations of cytoplasmic ROS levels were accountable for CMA induction and cytotoxic effects observed in TMZ sensitive cells after treatment. On the other hand, in resistant cells, TMZ failed in producing an increase in cytoplasmic ROS levels and CMA activation, preventing GBM cell toxicity. By increasing oxidative stress, CMA activation was recovered, as also cell cytotoxicity, especially in combination with TMZ treatment. Herein, for the first time, it is shown the relation between mitochondrial ROS release, CMA activation and TMZ-responsiveness in GBM.

scholarly journals EXTH-50. THIOREDOXIN REDUCTASE1 AND MGMT SYNTHETIC LETHALITY ENHANCES CYTOTOXICITY OF PRIMA-1MET(APR-246) AND AURANOFIN IN GLIOBLASTOMA

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi93-vi93
Author(s):  
Rehka Raveendrakumar ◽  
Bassam Abdulkarim ◽  
Monisha Bagchi ◽  
Paul Daniel ◽  
Aymane Deri ◽  
...  
Keyword(s):  
Cell Lines ◽  
Dna Methyltransferase ◽  
Synthetic Lethality ◽  
Buthionine Sulfoximine ◽  
Redox Balance ◽  
Redox Status ◽  
Inhibitory Effects ◽  
Cytotoxic Effects ◽  
Growth Inhibitory ◽  
Low Levels

Abstract Glioblastoma multiforme (GBM), the most common and advanced primary brain malignancy in adults remains an incurable disease, despite aggressive treatment with surgery, radiation therapy and chemoradiation using the alkylating agent, Temozolomide (TMZ). PRIMA-1MET (APR-246), a small molecule designed to restore mutant (mut)p53 function has been shown to affect cellular redox status through targeting thioredoxin reductase 1 (TrxR1) in wild-type (wt)p53 cancer cells. We have recently shown that PRIMA-1MET exerts cytotoxic effects status preferentially in GBM cell lines expressing low levels of the DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT), known for its role in resistance to TMZ. We hypothesized that PRIMA-1MET mediates its growth inhibitory effects by modulating the redox balance and investigated the potential relationship between MGMT, redox balance and TrxR1. We show that PRIMA-1MET decreased TrxR1 expression levels preferentially in MGMT-low expressing isogenic GBM cell lines. Using pharmacological agents that modulate reactive oxygen species (ROS) levels i.e., ROS scavenger, N-acetylcysteine and ROS inducer, L-Buthionine-Sulfoximine, we show that PRIMA-1MET exerts its growth-inhibitory effects through increased ROS. Strikingly, we identified a novel positive relationship between MGMT and TrxR1, wherein high MGMT expression is associated with high expression of TrxR1 and low levels of ROS. Treatment with the MGMT inhibitor, O6-Benzylguanine, or the TrxR1-targeting FDA-approved drug Auranofin validated our findings. Interestingly, the latter exerted significantly more pronounced cytotoxic effects compared to PRIMA-1MET in GBM cell lines. Additional studies are warranted to assess PRIMA-1MET in combination with TrxR1-targeting therapies and propose repurposing of Auranofin as a novel strategy to improve the dismal outcome of patients with GBM.

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