scholarly journals EXTH-58. INHIBITION OF DNA TOPOISOMERASE 1 AND POLY(ADP-RIBOSE) POLYMERASE SYNERGISTICALLY INDUCES CELL DEATH IN GLIOBLASTOMA WITH PTEN LOSS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi94-vi95
Author(s):  
Madison Butler ◽  
Yu-Ting Su ◽  
Lee Hwang ◽  
Laetitia Marzi ◽  
Mark Gilbert ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Viability ◽  
Combination Treatment ◽  
Dna Supercoiling ◽  
Glioblastoma Cell ◽  
Pten Loss ◽  
Topoisomerase 1

Abstract BACKGROUND Glioblastoma is known for its aggressive behavior and resistance to most available treatments. Topoisomerase 1 (Top1) functions by relaxing DNA supercoiling to facilitate replication. The novel Top1 inhibitor, LMP400, traps the enzyme and prevents its normal function, particularly in highly proliferative cells, resulting in DNA damage. Poly(ADP-ribose) polymerase (PARP) is involved in DNA repair responses triggered by Top1 inhibition. Phosphatase and tensin homolog (PTEN) loss, a frequent occurrence in glioblastoma, promotes DNA damage repair deficiency. We hypothesize that PTEN loss presents a vulnerability to combined induction of DNA damage and inhibition of repair mechanisms. METHODS Human glioblastoma cells were treated with LMP400 and/or Olaparib, a PARP inhibitor. Effects on cell proliferation and cell death were determined using a Beckman Coulter cell viability analyzer and colony formation assays. Synergism was calculated using COMPUSYN software. Cell cycle analysis was performed by FACS with EdU/DAPI staining, and Western blotting of lysate from drug-treated cells was performed to explore mechanisms of cytotoxicity. RESULTS LMP400 inhibited cell proliferation with an EC50 of 8.0 nM in U251 cells, and combination of LMP400 and Olaparib had a synergistic cytotoxic effect. Combination treatment enhanced activation of ATM-Chk2 and ATR-Chk1 pathways involved in DNA damage response signaling and increased S phase arrest. Increased protein expression of gamma-H2AX, cleaved caspase 3, and cleaved PARP was observed in combination-treated cells compared to single agents. Cell viability assays using isogenic glioblastoma cell lines with and without PTEN indicate that PTEN loss increases sensitivity to combination treatment. CONCLUSION Our results suggest that LMP400 and Olaparib combined treatment synergistically induces glioblastoma cell death, partially through inducing DNA damage, cell cycle arrest, and apoptosis. Mechanistic studies to investigate this vulnerability in glioblastoma with PTEN loss are ongoing. These results may lead to an effective personalized therapy for a molecularly defined subset of glioblastoma patients.

Mevalonate pathway inhibitors in the treatment of B-cell chronic lymphocytic leukemia.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 6561-6561
Author(s):  
Ravi Kiran Bobba ◽  
Indira Benakanakere ◽  
Smitha Bearelly ◽  
Monica Arya ◽  
Richard Sleigtholm ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Viability ◽  
B Cell ◽  
Combination Treatment ◽  
Mevalonate Pathway ◽  
Chemotherapeutic Agents ◽  
Lymphocytic Leukemia ◽  
Cell Chronic Lymphocytic Leukemia

6561 Background: B-cell chronic lymphocytic leukemia (CLL) cells are arrested in G0/G1 phase of the cell cycle and are resistant to programmed cell death, hypothesized to contribute to the resistance of CLL cells to standard chemotherapy with curative intent. Methods: Mec-2 cells and Wac-3 cells are CLL cells that have been shown to be resistant to fludarabine and rituximab. We tested a novel enzyme inhibitor’s ability to render CLL cells sensitive to fludarabine and rituximab. Results: BIBB515, a lanosterol synthase inhibitor, at a concentration of 10μM, was able to reduce the cell viability from 82% in controls to 65% after 72 hours. Fludarabine 10μM alone did not reduce the cell viability, 82 % in controls compared to 80%. BIBB515+ fludarabine treatment for 72 hours, at the dose of 10μM each decreased the cell viability to 37%. Cell proliferation by MTT assay was 0.66±0.010 in control compared to 0.37±0.01 in BIBB515+fludarbine and 0.21±0.01 in BIBB515+ fludarabine+ rituximab. There is a 68% down-regulation of cell proliferation using this treatment. There was a two fold induction of CD 20 with combination treatment, and BIBB515 treatment. The mechanism of cell death in the combination treatment of BIBB515 and fludarabine may be due to the up regulation of cell surface marker CD-20. WAC-3 is another CLL cell line that is sensitive to fludarabine, and resistant to rituximab. BIBB515 sensitizes WAC-3 cells to CD 20 antibody rituximab. There is a 68.7% decrease in cell proliferation with combination treatment of BIBB515 and rituximab. Proliferation of Mec-2 cells were inhibited by 60µM and 30µM terbinafine. Ro-48-8071, showed dose-dependent activity, alone or in combination to fludarabine was seen to induce cell death in Mec-2 cells. Fludarabine alone did not have any effect on these cells. Conclusions: Inhibitors of the mevalonate pathway make resistant CLL cells sensitive to current chemotherapeutic agents. Exploiting this mechanism could alter the current treatment regimens, leading to control of the disease in advanced stages by either inducing the leukemic cells to be static or to regress. This strategy may also limit the toxicities involved with chemotherapy.

scholarly journals Equivalent effect of DNA damage-induced apoptotic cell death or long-term cell cycle arrest on colon carcinoma cell proliferation and tumour growth

Oncogene ◽  
2005 ◽  
Vol 25 (2) ◽  
pp. 165-175 ◽  
Author(s):  
M R Bhonde ◽  
M-L Hanski ◽  
M Notter ◽  
B F Gillissen ◽  
P T Daniel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Cell Death ◽  
Tumour Growth ◽  
Carcinoma Cell ◽  
Apoptotic Cell ◽  
Cycle Arrest ◽  
Equivalent Effect

scholarly journals STAU2 protein level is controlled by caspases and the CHK1 pathway and regulates cell cycle progression in the non-transformed hTERT-RPE1 cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lionel Condé ◽  
Yulemi Gonzalez Quesada ◽  
Florence Bonnet-Magnaval ◽  
Rémy Beaujois ◽  
Luc DesGroseillers
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Steady State ◽  
Posttranscriptional Regulation ◽  
Cell Cycle Progression ◽  
Rna Binding ◽  
Regulation Of Gene Expression ◽  
Cycle Progression

AbstractBackgroundStaufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from theSTAU2gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation.ResultsCRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism.ConclusionsThese results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway.

scholarly journals SOG1 transcription factor promotes the onset of endoreduplication under salinity stress in Arabidopsis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kalyan Mahapatra ◽  
Sujit Roy
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Transcription Factor ◽  
Programmed Cell Death ◽  
Salinity Stress ◽  
Crucial Role ◽  
Genome Stability ◽  
Cell Cycle Checkpoint ◽  
Cell Cycle Regulators

AbstractAs like in mammalian system, the DNA damage responsive cell cycle checkpoint functions play crucial role for maintenance of genome stability in plants through repairing of damages in DNA and induction of programmed cell death or endoreduplication by extensive regulation of progression of cell cycle. ATM and ATR (ATAXIA-TELANGIECTASIA-MUTATED and -RAD3-RELATED) function as sensor kinases and play key role in the transmission of DNA damage signals to the downstream components of cell cycle regulatory network. The plant-specific NAC domain family transcription factor SOG1 (SUPPRESSOR OF GAMMA RESPONSE 1) plays crucial role in transducing signals from both ATM and ATR in presence of double strand breaks (DSBs) in the genome and found to play crucial role in the regulation of key genes involved in cell cycle progression, DNA damage repair, endoreduplication and programmed cell death. Here we report that Arabidopsis exposed to high salinity shows generation of oxidative stress induced DSBs along with the concomitant induction of endoreduplication, displaying increased cell size and DNA ploidy level without any change in chromosome number. These responses were significantly prominent in SOG1 overexpression line than wild-type Arabidopsis, while sog1 mutant lines showed much compromised induction of endoreduplication under salinity stress. We have found that both ATM-SOG1 and ATR-SOG1 pathways are involved in the salinity mediated induction of endoreduplication. SOG1was found to promote G2-M phase arrest in Arabidopsis under salinity stress by downregulating the expression of the key cell cycle regulators, including CDKB1;1, CDKB2;1, and CYCB1;1, while upregulating the expression of WEE1 kinase, CCS52A and E2Fa, which act as important regulators for induction of endoreduplication. Our results suggest that Arabidopsis undergoes endoreduplicative cycle in response to salinity induced DSBs, showcasing an adaptive response in plants under salinity stress.

scholarly journals The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2178
Author(s):  
Fabio Morandi ◽  
Veronica Bensa ◽  
Enzo Calarco ◽  
Fabio Pastorino ◽  
Patrizia Perri ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Cell Cycle Progression ◽  
Treatment Strategies ◽  
Annexin V ◽  
Dependent Manner ◽  
Induction Of Apoptosis ◽  
Dose Dependent

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

scholarly journals Differentiating life and death: An inflammatory affair

2018 ◽  
Author(s):  
Dustin Lane
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Differentiation ◽  
Programmed Cell Death ◽  
Signaling Networks ◽  
Inhibitors Of Apoptosis ◽  
Life And Death ◽  
Cell Death Signaling ◽  
Cycle Dependent

Programmed cell death signaling networks are frequently activated to coordinate the process of cell differentiation, and a variety of apoptotic events can mediate the process. This can include the ligation of death receptors, the activation of downstream caspases, and the induction of chromatin fragmentation, and all of these events can occur without downstream induction of death. Importantly, regulators of programmed cell death also have established roles in mediating differentiation. This review will provide an overview of apoptosis and its regulation by Inhibitors of Apoptosis (IAPs) and Bcl-2 family members. It will then outline the cross-talk between NF-ĸB and apoptotic signaling in the regulation of apoptosis before discussing the function of these regulators in the control of cell differentiation. It will end on a discussion of how a DNA damage-directed, cell cycle-dependent differentiation program may be controlled across multiple passages through cell cycle, and will assert that the failure to properly differentiate is the underlying cause of cancer.

scholarly journals RUNX Family Participates in the Regulation of p53-Dependent DNA Damage Response

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Toshinori Ozaki ◽  
Akira Nakagawara ◽  
Hiroki Nagase
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Cycle Arrest ◽  
Dna Damage Response ◽  
Apoptotic Cell ◽  
Genetic Alterations ◽  
Apoptotic Cell Death ◽  
Cycle Arrest ◽  
Damage Response

A proper DNA damage response (DDR), which monitors and maintains the genomic integrity, has been considered to be a critical barrier against genetic alterations to prevent tumor initiation and progression. The representative tumor suppressor p53 plays an important role in the regulation of DNA damage response. When cells receive DNA damage, p53 is quickly activated and induces cell cycle arrest and/or apoptotic cell death through transactivating its target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death such asp21WAF1,BAX, andPUMA. Accumulating evidence strongly suggests that DNA damage-mediated activation as well as induction of p53 is regulated by posttranslational modifications and also by protein-protein interaction. Loss of p53 activity confers growth advantage and ensures survival in cancer cells by inhibiting apoptotic response required for tumor suppression. RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor and is closely involved in a variety of cellular processes including development, differentiation, and/or tumorigenesis. In this review, we describe a background of p53 and a functional collaboration between p53 and RUNX family in response to DNA damage.

scholarly journals SDF-1α/MicroRNA-134 Axis Regulates Nonfunctioning Pituitary Neuroendocrine Tumor Growth via Targeting VEGFA

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiaoyu Wang ◽  
Yuanjian Fang ◽  
Yunxiang Zhou ◽  
Xiaoming Guo ◽  
Ke Xu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Neuroendocrine Tumor ◽  
Tumor Cells ◽  
Tumor Invasion ◽  
Expression Level ◽  
Qrt Pcr ◽  
Proliferation And Invasion

BackgroundNonfunctioning pituitary neuroendocrine tumor (NF-PitNET) is difficult to resect. Except for surgery, there is no effective treatment for NF-PitNET. MicroRNA-134 (miR-134) has been reported to inhibit proliferation and invasion ability of tumor cells. Herein, the mechanism underlying the effect of miR-134 on alleviating NF-PitNET tumor cells growth is explored.MethodsMouse pituitary αT3-1 cells were transfected with miR-134 mimics and inhibitor, followed by treatment with stromal cell-derived factor-1α (SDF-1α) in vitro. MiR-134 expression level: we used quantitative real-time PCR (qRT-PCR) to detect the expression of miR-134. Cell behavior level: cell viability and invasion ability were assessed using a cell counting kit-8 (CCK8) assay and Transwell invasion assay respectively. Cytomolecular level: tumor cell proliferation was evaluated by Ki-67 staining; propidium iodide (PI) staining analyzed the effect of miR-134 on cell cycle arrest; western blot analysis and immunofluorescence staining evaluated tumor migration and invasive ability. Additionally, we collected 27 NF-PitNET tumor specimens and related clinical data. The specimens were subjected to qRT-PCR to obtain the relative miR-134 expression level of each specimen; linear regression analysis was used to analyze the miR-134 expression level in tumor specimens and the age of the NF-PitNET population, gender, tumor invasion, prognosis, and other indicators.ResultsIn vitro experiment, miR-134 was observed to significantly inhibit αT3-1 cells proliferation characterized by inhibited cell viability and expressions of vascular endothelial growth factor A (VEGFA) and cell cycle transition from G1 to S phase (P < 0.01). VEGFA was verified as a target of miR-134. Additionally, miR-134-induced inhibition of αT3-1 cell proliferation and invasion was attenuated by SDF-1α and VEGFA overexpression (P < 0.01). In primary NF-PitNET tumor analysis, miR-134 expression level was negatively correlated with tumor invasion (P = 0.003).ConclusionThe regulation of the SDF-1α/miR-134/VEGFA axis represents a novel mechanism in the pathogenesis of NF-PitNETs and may serve as a potential therapeutic target for the treatment of NF-PitNETs.

scholarly journals AXL and CAV-1 play a role for MTH1 inhibitor TH1579 sensitivity in cutaneous malignant melanoma

2020 ◽  
Vol 27 (7) ◽  
pp. 2081-2098 ◽  
Author(s):  
Ishani Das ◽  
Helge Gad ◽  
Lars Bräutigam ◽  
Linda Pudelko ◽  
Rainer Tuominen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
Cell Death ◽  
Malignant Melanoma ◽  
Braf Inhibitor ◽  
Mitotic Arrest ◽  
Cutaneous Malignant Melanoma ◽  
Clinical Samples

AbstractCutaneous malignant melanoma (CMM) is the deadliest form of skin cancer and clinically challenging due to its propensity to develop therapy resistance. Reactive oxygen species (ROS) can induce DNA damage and play a significant role in CMM. MTH1 protein protects from ROS damage and is often overexpressed in different cancer types including CMM. Herein, we report that MTH1 inhibitor TH1579 induced ROS levels, increased DNA damage responses, caused mitotic arrest and suppressed CMM proliferation leading to cell death both in vitro and in an in vivo xenograft CMM zebrafish disease model. TH1579 was more potent in abrogating cell proliferation and inducing cell death in a heterogeneous co-culture setting when compared with CMM standard treatments, vemurafenib or trametinib, showing its broad anticancer activity. Silencing MTH1 alone exhibited similar cytotoxic effects with concomitant induction of mitotic arrest and ROS induction culminating in cell death in most CMM cell lines tested, further emphasizing the importance of MTH1 in CMM cells. Furthermore, overexpression of receptor tyrosine kinase AXL, previously demonstrated to contribute to BRAF inhibitor resistance, sensitized BRAF mutant and BRAF/NRAS wildtype CMM cells to TH1579. AXL overexpression culminated in increased ROS levels in CMM cells. Moreover, silencing of a protein that has shown opposing effects on cell proliferation, CAV-1, decreased sensitivity to TH1579 in a BRAF inhibitor resistant cell line. AXL-MTH1 and CAV-1-MTH1 mRNA expressions were correlated as seen in CMM clinical samples. Finally, TH1579 in combination with BRAF inhibitor exhibited a more potent cell killing effect in BRAF mutant cells both in vitro and in vivo. In summary, we show that TH1579-mediated efficacy is independent of BRAF/NRAS mutational status but dependent on the expression of AXL and CAV-1.

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