Activation of Myosin Phosphatase by Epigallocatechin-Gallate Sensitizes THP-1 Leukemic Cells to Daunorubicin

2020 ◽  
Vol 20 ◽  
Author(s):  
Emese Tóth ◽  
Ferenc Erdődi ◽  
Andrea Kiss
Keyword(s):  
Tumor Suppressor ◽  
Cell Viability ◽  
Combined Treatment ◽  
Epigallocatechin Gallate ◽  
Chemotherapeutic Agents ◽  
Leukemic Cells ◽  
Regulatory Subunit ◽  
Regulatory Function ◽  
Myosin Phosphatase ◽  
Tumor Suppressor Proteins

Background: The Myosin Phosphatase (MP) holoenzyme is composed of a Protein Phosphatase type 1 (PP1) catalytic subunit and a regulatory subunit termed Myosin Phosphatase Target subunit 1 (MYPT1). Besides dephosphorylation of myosin, MP has been implicated in the control of cell proliferation via dephosphorylation and activation of the tumor suppressor gene products, retinoblastoma protein (pRb) and merlin. Inhibition of MP was shown to attenuate the drug-induced cell death of leukemic cells by chemotherapeutic agents, while activation of MP might have a sensitizing effect. Objective: Recently, Epigallocatechin-Gallate (EGCG), a major component of green tea, was shown to activate MP by inducing the dephosphorylation of MYPT1 at phospho-Thr696 (MYPT1pT696), which might confer enhanced chemosensitivity to cancer cells. Methods: THP-1 leukemic cells were treated with EGCG and Daunorubicin (DNR) and cell viability was analyzed. Phosphorylation of tumor suppressor proteins was detected by Western blotting. Results: EGCG or DNR (at sub-lethal doses) alone had moderate effects on cell viability, while the combined treatment caused a significant decrease in the number of viable cells by enhancing apoptosis and decreasing proliferation. EGCG plus DNR decreased the phosphorylation level of MYPT1pT696, which was accompanied by prominent dephosphorylation of pRb. In addition, significant dephosphorylation of merlin was observed when EGCG and DNR were applied together. Conclusion: Our results suggest that EGCG-induced activation of MP might have a regulatory function in mediating the chemosensitivity of leukemic cells via dephosphorylation of tumor suppressor proteins.

Prelinical Evaluation of Lyn Kinase Inhibition for the Treatment of B Cell Chronic Lymphocytic Leukemia (B-CLL).

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3447-3447
Author(s):  
Vamsidhar Velcheti ◽  
Li Li ◽  
Joseph Philips ◽  
Jyotsna Fuloria ◽  
Francis R Rodwig ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Viability ◽  
B Cell ◽  
Combined Treatment ◽  
Chemotherapeutic Agents ◽  
Negative Regulator ◽  
Cell Leukemia ◽  
Lyn Kinase ◽  
Control Peptide ◽  
Inhibitor Peptide

Abstract Abstract 3447 Poster Board III-335 B-CLL is characterized by the accumulation of mature B lymphocytes incapable of undergoing apoptosis. Although several mechanisms have been implicated in the apoptotic defects in B-CLL cells, the signal transduction pathways underlying these defects remain unresolved. Lyn kinase is known to be a negative regulator of apoptosis, and is linked to chemo-resistance. Our preliminary study indicated that Lyn activity was 4- to 7-fold higher in primary B cells from six randomly-selected B-CLL patients than in normal B cells from healthy donors. Treatment of the B-CLL cells for 4 h with 10 μM concentration of a Lyn-specific inhibitor peptide targeting a unique interaction site within Lyn (Cancer Res. 2004;64:1058) resulted in 40 to 50% inhibition of Lyn kinase activity compared to negligible inhibition with control peptide. Further, treatment of the B-CLL cells for 16 to 20 h with the Lyn inhibitor peptide at 5 μM and 10 μM concentrations, decreased the cell viability by ∼25% and ∼50%, respectively, compared with no peptide or the control peptide. Fludarabine is one of the key chemotherapeutic agents for B-CLL and is known to induce cell death by apoptosis. The combined treatment with Lyn inhibitor peptide (5 μM) and fludarabine (2 μg/ml), decreased cell viability by ∼50% compared to ∼25% decrease with fludarabine or Lyn inhibitor peptide alone. In addition, the combined treatment showed ∼75% increase in caspase-3/7 activity compared to ∼25% increase with the Lyn inhibitor peptide or fludarabine alone. Because, overexpression of antiapoptotic proteins is correlated with apoptotic resistance of B-CLL cells, we examined the effect of Lyn inhibitor peptide on the changes in the expression of antiapoptotic genes, myeloid cell leukemia-1 (Mcl-1), x-linked inhibitor of apoptosis (XIAP), and B-cell leukemia/lymphoma-2 (Bcl-2). Treatment of B-CLL cells with 10 μM Lyn inhibitor peptide for 16 to 20 h resulted in more than 50% decreases in the expression of all the three antiapoptotic genes. Further, the Lyn inhibitor peptide markedly inhibited NF-κB activation (∼60%) and VEGF production (∼80%), both strongly implicated in the apoptotic resistance of B-CLL cells. Collectively, our results suggest that targeting Lyn kinase pathway with a clinically relevant Lyn kinase inhibitor may have a therapeutic potential for B-CLL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Enhancing Radiotherapy Using Ultrasound And Microbubbles With Gold Nanoparticles

2021 ◽  
Author(s):  
Amanda T.L. Tran
Keyword(s):  
Gold Nanoparticles ◽  
Cell Death ◽  
Radiation Dose ◽  
Cell Viability ◽  
Therapeutic Effect ◽  
Combined Treatment ◽  
Genetic Material ◽  
Chemotherapeutic Agents ◽  
Enhanced Permeability And Retention ◽  
Local Radiation

Gold nanoparticles (AuNPs) have been shown to enhance the local radiation dose in tumour mice models. Although AuNPs can be delivered to tumours through enhanced permeability and retention (EPR) effect, delivering of AuNP for therapeutic effect has been proven to be challenging. The application of ultrasound and microbubbles (USMB) has been shown to increase the delivery of genetic material, macromolecules, and chemotherapeutic agents. The hypothesis driving this research is that ultrasound and microbubbles can increase uptake of AuNPs in cells. The results suggest that AuNPs, and USMB aid in its delivery to increase cell death upon irradiation. An improvement of ~ 22 fold was observed with the combined treatment compared to radiation only, implying synergism. In addition, USMB and radiation exhibited an increase in cell death. Cell viability was ~3-4% and is dependent on AuNP concentration, shape and location. Further investigation of this concept was done

scholarly journals Chemotherapeutic Effect of SR9009, a REV-ERB Agonist, on the Human Glioblastoma T98G Cells

ASN NEURO ◽  
2019 ◽  
Vol 11 ◽  
pp. 175909141989271 ◽  
Author(s):  
Paula M. Wagner ◽  
Natalia M. Monjes ◽  
Mario E. Guido
Keyword(s):  
Glioblastoma Multiforme ◽  
Cell Viability ◽  
Circadian Clock ◽  
Cell Cycle Progression ◽  
Synergistic Effects ◽  
Cell Metabolism ◽  
Combined Treatment ◽  
Chemotherapeutic Agents ◽  
Pharmacological Modulation

Glioblastoma multiforme is the most aggressive brain tumor, and human T98G cells constitute a useful glioblastoma multiforme model to evaluate the chemotherapeutic agents. Modern life (shiftwork, jetlag, etc.) may cause circadian disorganization promoting higher cancer risk and metabolic disorders. Although little is known about the tumor-intrinsic circadian clock function, pharmacological modulation of circadian components may offer selective anticancer strategies. REV-ERBs are heme-binding circadian clock components acting as repressors of processes involved in tumorigenesis such as metabolism, proliferation, and inflammation. A synthetic pyrrole derivative (SR9009) that acts as REV-ERBs-specific agonists exhibits potent in vivo activity on metabolism and tumor cell viability. Here, we investigated SR9009 effects on T98G cell viability, differential chemotherapy time responses, and underlying metabolic processes (reactive oxygen species [ROS] and lipid droplets [LDs]) and compared it with the proteasome inhibitor Bortezomib treatment. SR9009-treated cells exhibited significant reduction in cell viability with consequences on cell cycle progression. Dexamethasone synchronized cells displayed differential time responses to SR9009 treatment with highest responses 18 to 30 h after synchronization. SR9009 treatment decreased ROS levels while Bortezomib increased them. However, both treatments significantly increased LD levels, whereas the combined treatment showed additive or synergistic effects between both drugs. In addition, we extended these studies to HepG2 cells which also showed a significant decrease in cell viability and ROS levels and the increase in LD levels after SR9009 treatment. Our results suggest that the pharmacological modulation of the tumor-intrinsic clock by REV-ERB agonists severely affects cell metabolism and promotes cytotoxic effects on cancer cells.

Applications of magnetoliposomes with encapsulated doxorubicin for integrated chemotherapy and hyperthermia of rat C6 glioma

2018 ◽  
Vol 73 (7-8) ◽  
pp. 265-271 ◽  
Author(s):  
Natália Babincová ◽  
Paul Sourivong ◽  
Peter Babinec ◽  
Christian Bergemann ◽  
Melánia Babincová ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cell Viability ◽  
Targeted Delivery ◽  
Combined Treatment ◽  
Chemotherapeutic Agents ◽  
Alternating Magnetic Field ◽  
Magnetic Drug Targeting ◽  
Complete Regression

Abstract There is substantial evidence regarding enhanced antitumor cytotoxicity of selected chemotherapeutic agents by appropriate heat exposure (40–44°C). Based upon these results, the integration of hyperthermia as an additional treatment modality given simultaneously with systemic chemotherapy is currently of considerable interest. Hyperthermia can be induced by alternating magnetic field and magnetic nanoparticles. Thus, we have used thermosensitive magnetoliposomes that contained superparamagnetic iron oxide nanoparticles and doxorubicin for in vitro and in vivo therapy of rat glioma C6. The results showed that magnetoliposomes can be specifically heated to 43°C (phase transition temperature of a used lipid composition) in a few minutes, and during this, the encapsulated doxorubicin is released in a controllable manner. The in vitro experiments showed that the cell viability decreased to 79.2% after heat treatment alone and to 47.4% for doxorubicin-loaded magnetoliposomes without application of alternating magnetic field, while the combined treatment resulted in 17.3% cell viability. Also, in vivo results demonstrated that magnetic drug targeting has a strong antiglioma effect with a tumor volume growth inhibition and complete regression. Such targeted delivery and controlled release of anticancer agents would provide clinical advantages compared with currently available methods.

scholarly journals Enhancing Radiotherapy Using Ultrasound And Microbubbles With Gold Nanoparticles

2021 ◽  
Author(s):  
Amanda T.L. Tran
Keyword(s):  
Gold Nanoparticles ◽  
Cell Death ◽  
Radiation Dose ◽  
Cell Viability ◽  
Therapeutic Effect ◽  
Combined Treatment ◽  
Genetic Material ◽  
Chemotherapeutic Agents ◽  
Enhanced Permeability And Retention ◽  
Local Radiation

Gold nanoparticles (AuNPs) have been shown to enhance the local radiation dose in tumour mice models. Although AuNPs can be delivered to tumours through enhanced permeability and retention (EPR) effect, delivering of AuNP for therapeutic effect has been proven to be challenging. The application of ultrasound and microbubbles (USMB) has been shown to increase the delivery of genetic material, macromolecules, and chemotherapeutic agents. The hypothesis driving this research is that ultrasound and microbubbles can increase uptake of AuNPs in cells. The results suggest that AuNPs, and USMB aid in its delivery to increase cell death upon irradiation. An improvement of ~ 22 fold was observed with the combined treatment compared to radiation only, implying synergism. In addition, USMB and radiation exhibited an increase in cell death. Cell viability was ~3-4% and is dependent on AuNP concentration, shape and location. Further investigation of this concept was done

scholarly journals CDK5RAP3 Participates in Autophagy Regulation and Is Downregulated in Renal Cancer

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Jun Li ◽  
Xinyi Hu ◽  
Ming Su ◽  
Hongliang Shen ◽  
Wei Qiu ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Cell Viability ◽  
Cancer Cells ◽  
Renal Cancer ◽  
Significant Inhibition ◽  
Regulatory Subunit ◽  
Putative Tumor Suppressor ◽  
Cancer Tissues ◽  
P Cells ◽  
Urological Tumors

Renal cancer is one of the most common malignant urological tumors; however, its diagnosis and treatment are not well established. In the present study, we identified that CDK5 regulatory subunit-associated protein 3 (CDK5RAP3), a putative tumor suppressor in many cancers, was downregulated in renal cancer tissues. Through loss- and gain-of-function experiments, we observed that the action of CDK5RAP3 in renal cancer cells was different in Caki-1 and 769-P cell lines. Knockdown of endogenous CDK5RAP3 in Caki-1 slightly increased cell viability, whereas overexpression of CDK5RAP3 in 769-P cells inhibited cell viability. In addition, we observed that CDK5RAP3 participated in the regulation of autophagy in renal cancer. Knockdown of CDK5RAP3 induced significant inhibition of autophagy in Caki-1 cells but not in 769-P cells. In contrast, overexpression of CDK5RAP3 significantly activated autophagy in 769-P cells, as evidenced by increased LC3-II levels. However, the LC3-II could not be altered by CDK5RAP3 overexpression in Caki-1 cells. These findings demonstrated that CDK5RAP3 is downregulated in renal cancer and may be associated with autophagy.

iTSP-PseAAC: Identify Tumor Suppressor Proteins by Using Fully Connected Neural Network and PseAAC

2021 ◽  
Vol 15 ◽  
Author(s):  
Muhammad Awais ◽  
Waqar Hussain ◽  
Nouman Rasool ◽  
Yaser Daanial Khan
Keyword(s):  
Tumor Suppressor ◽  
Cross Validation ◽  
Control Cell ◽  
Normal Function ◽  
In Vivo Studies ◽  
Tumor Suppressor Proteins ◽  
Proposed Model ◽  
Self Consistency

Background: The uncontrolled growth due to accumulation of genetic and epigenetic changes as a result of loss or reduction in the normal function of Tumor Suppressor Genes (TSGs) and Pro-oncogenes is known as cancer. TSGs control cell division and growth by repairing of DNA mistakes during replication and restrict the unwanted proliferation of a cell or activities, those are the part of tumor production. Objectives: This study aims to propose a novel, accurate, user-friendly model to predict tumor suppressor proteins, which would be freely available to experimental molecular biologists to assist them using in vitro and in vivo studies. Methods: The predictor model has used the input feature vector (IFV) calculated from the physicochemical properties of proteins based on FCNN to compute the accuracy, sensitivity, specificity, and MCC. The proposed model was validated against different exhaustive validation techniques i.e. self-consistency and cross-validation. Results: Using self-consistency, the accuracy is 99%, for cross-validation and independent testing has 99.80% and 100% accuracy respectively. The overall accuracy of the proposed model is 99%, sensitivity value 98% and specificity 99% and F1-score was 0.99. Conclusion: It concludes, the proposed model for prediction of the tumor suppressor proteins can predict the tumor suppressor proteins efficiently, but it still has space for improvements in computational ways as the protein sequences may rapidly increase, day by day.

scholarly journals Anthracycline-induced cytotoxicity in the GL261 glioma model system

2021 ◽  
Author(s):  
Amber M. Tavener ◽  
Megan C. Phelps ◽  
Richard L. Daniels
Keyword(s):  
Cell Viability ◽  
Tumor Cells ◽  
Flow Cytometric Analysis ◽  
Annexin V ◽  
Chemotherapeutic Agents ◽  
Cytotoxic Effects ◽  
High Concentrations ◽  
Induced Apoptosis ◽  
Dose Dependent ◽  
Gl261 Glioma

AbstractGlioblastoma (GBM) is a lethal astrocyte-derived tumor that is currently treated with a multi-modal approach of surgical resection, radiotherapy, and temozolomide-based chemotherapy. Alternatives to current therapies are urgently needed as its prognosis remains poor. Anthracyclines are a class of compounds that show great potential as GBM chemotherapeutic agents and are widely used to treat solid tumors outside the central nervous system. Here we investigate the cytotoxic effects of doxorubicin and other anthracyclines on GL261 glioma tumor cells in anticipation of novel anthracycline-based CNS therapies. Three methods were used to quantify dose-dependent effects of anthracyclines on adherent GL261 tumor cells, a murine cell-based model of GBM. MTT assays quantified anthracycline effects on cell viability, comet assays examined doxorubicin genotoxicity, and flow cytometry with Annexin V/PI staining characterized doxorubicin-induced apoptosis and necrosis. Dose-dependent reductions in GL261 cell viability were found in cells treated with doxorubicin (EC50 = 4.9 μM), epirubicin (EC50 = 5.9 μM), and idarubicin (EC50 = 4.4 μM). Comet assays showed DNA damage following doxorubicin treatments, peaking at concentrations of 1.0 μM and declining after 25 μM. Lastly, flow cytometric analysis of doxorubicin-treated cells showed dose-dependent induction of apoptosis (EC50 = 5.2 μM). Together, these results characterized the cytotoxic effects of anthracyclines on GL261 glioma cells. We found dose-dependent apoptotic induction; however at high concentrations we find that cell death is likely necrotic. Our results support the continued exploration of anthracyclines as compounds with significant potential for improved GBM treatments.

scholarly journals Differential Effects of Combined ATR/WEE1 Inhibition in Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3790
Author(s):  
Gro Elise Rødland ◽  
Sissel Hauge ◽  
Grete Hasvold ◽  
Lilli T. E. Bay ◽  
Tine T. H. Raabe ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Viability ◽  
Cancer Treatment ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Combined Treatment ◽  
Cancer Cell Lines ◽  
Variable Extent ◽  
Synergistic Induction

Inhibitors of WEE1 and ATR kinases are considered promising for cancer treatment, either as monotherapy or in combination with chemo- or radiotherapy. Here, we addressed whether simultaneous inhibition of WEE1 and ATR might be advantageous. Effects of the WEE1 inhibitor MK1775 and ATR inhibitor VE822 were investigated in U2OS osteosarcoma cells and in four lung cancer cell lines, H460, A549, H1975, and SW900, with different sensitivities to the WEE1 inhibitor. Despite the differences in cytotoxic effects, the WEE1 inhibitor reduced the inhibitory phosphorylation of CDK, leading to increased CDK activity accompanied by ATR activation in all cell lines. However, combining ATR inhibition with WEE1 inhibition could not fully compensate for cell resistance to the WEE1 inhibitor and reduced cell viability to a variable extent. The decreased cell viability upon the combined treatment correlated with a synergistic induction of DNA damage in S-phase in U2OS cells but not in the lung cancer cells. Moreover, less synergy was found between ATR and WEE1 inhibitors upon co-treatment with radiation, suggesting that single inhibitors may be preferable together with radiotherapy. Altogether, our results support that combining WEE1 and ATR inhibitors may be beneficial for cancer treatment in some cases, but also highlight that the effects vary between cancer cell lines.

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