Down-regulation of 14-3-3β exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP–Wnt pathway

Background: Cancer cells are frequently addicted to deregulated oncogenic protein translation that usually arises as a consequence of increased signaling flux from eIF4F activation. The small molecule 4EG-I, a potent inhibitor of translation initiation through disrupting eIF4E/eIF4G interaction, has been shown to exert anticancer effects in animal models of human cancers. Methods: Here, we extensively investigated the anticancer activity of 4EGI-1 in human glioma U87 cells. The anti-cancer effects of 4EGI-1 were measured by cell viability, lactate dehydrogenase (LDH) release, TUNEL staining, flow cytometry and western blot analysis in vitro, and also examined in a U87 xenograft model in vivo. The potential underlying molecular mechanisms were investigated by measuring mitochondrial function and ER stress. Results: We found that 4EGI-1 impaired the assembly of the eIF4F complex and decreased the expression of the eIF4E regulated proteins. The results of TUNEL staining and flow cytometry showed that 4EGI-1 treatment induced apoptotic cell death in a dose-dependent manner. Furthermore, 4EGI-1-induced apoptosis in U87 cells was associated with mitochondrial dysfunction and activation of the intrinsic mitochondrial pathway, which was dependent on the induction of the pro-apoptotic protein Bax. In addition, 4EGI-1 treatment triggered ER stress, which was evidenced by morphological changes of ER lumen and ER calcium release, as well as the dose-dependent increases in the expression of ER stress related proteins. Moreover, knockdown of the ER chaperone GRP-78 through siRNA was shown to partially reverse the 4EGI-1-induced ER stress in U87 cells. In vivo, 4EGI-1 strongly inhibited growth of U87 glioma xenografts without any apparent organ related toxicities. Conclusion: These data indicate that the use of inhibitors that directly target the translation initiation complex eIF4F could represent a potential novel approach for human glioma therapy.

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Anti-Cancer Effect of Metabotropic Glutamate Receptor 1 Inhibition in Human Glioma U87 Cells: Involvement of PI3K/Akt/mTOR Pathway

Cellular Physiology and Biochemistry ◽

10.1159/000369707 ◽

2015 ◽

Vol 35 (2) ◽

pp. 419-432 ◽

Cited By ~ 30

Author(s):

Chi Zhang ◽

Xian-rui Yuan ◽

Hao-yu Li ◽

Zi-jin Zhao ◽

Yi-wei Liao ◽

...

Keyword(s):

Cell Cycle ◽

Cell Viability ◽

Cell Invasion ◽

Human Glioma ◽

Invasion And Migration ◽

Metabotropic Glutamate ◽

Anti Cancer ◽

And Migration ◽

U87 Cells

Background: Metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors that mediate neuronal excitability and synaptic plasticity in the central nervous system, and emerging evidence suggests a role of mGluRs in the biology of cancer. Previous studies showed that mGluR1 was a potential therapeutic target for the treatment of breast cancer and melanoma, but its role in human glioma has not been determined. Methods: In the present study, we investigated the effects of mGluR1 inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA) or selective antagonists Riluzole and BAY36-7620. The anti-cancer effects of mGluR1 inhibition were measured by cell viability, lactate dehydrogenase (LDH) release, TUNEL staining, cell cycle assay, cell invasion and migration assays in vitro, and also examined in a U87 xenograft model in vivo. Results: Inhibition of mGluR1 significantly decreased the cell viability but increased the LDH release in a dose-dependent fashion in U87 cells. These effects were accompanied with the induction of caspase-dependent apoptosis and G0/G1 cell cycle arrest. In addition, the results of Matrigel invasion and cell tracking assays showed that inhibition of mGluR1 apparently attenuated cell invasion and migration in U87 cells. All these anti-cancer effects were ablated by the mGluR1 agonist L-quisqualic acid. The results of western blot analysis showed that mGluR1 inhibition overtly decreased the phosphorylation of PI3K, Akt, mTOR and P70S6K, indicating the mitigated activation of PI3K/Akt/mTOR pathway. Moreover, the anti-tumor activity of mGluR1 inhibition in vivo was also demonstrated in a U87 xenograft glioma model in athymic nude mice. Conclusion: The remarkable efficiency of mGluR1 inhibition to induce cell death in U87 cells may find therapeutic application for the treatment of glioma patients.

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The Wnt Pathway as a Target for Small Synthetic Anti-Cancer Molecules

Current Chemical Biology ◽

10.2174/2212796810701020227 ◽

2007 ◽

Vol 1 (2) ◽

pp. 227-239

Author(s):

Sonja Rohrs ◽

Oliver Muller

Keyword(s):

Wnt Pathway ◽

Anti Cancer

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Down regulation of DJ-1 enhances cell death by oxidative stress, ER stress, and proteasome inhibition

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2003.11.056 ◽

2003 ◽

Vol 312 (4) ◽

pp. 1342-1348 ◽

Cited By ~ 258

Author(s):

Takanori Yokota ◽

Kanako Sugawara ◽

Kaoru Ito ◽

Ryosuke Takahashi ◽

Hiroyoshi Ariga ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Er Stress ◽

Proteasome Inhibition ◽

Down Regulation

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Temozolomide Induces the Acquisition of Invasive Phenotype by O6-Methylguanine-DNA Methyltransferase (MGMT)+ Glioblastoma Cells in a Snail-1/Cx43-Dependent Manner

International Journal of Molecular Sciences ◽

10.3390/ijms22084150 ◽

2021 ◽

Vol 22 (8) ◽

pp. 4150

Author(s):

Paweł Kochanowski ◽

Jessica Catapano ◽

Maciej Pudełek ◽

Tomasz Wróbel ◽

Zbigniew Madeja ◽

...

Keyword(s):

Dna Methyltransferase ◽

Treatment Result ◽

Dependent Manner ◽

Down Regulation ◽

Cx43 Expression ◽

Cell Lineages ◽

Methylguanine Dna Methyltransferase ◽

U87 Cells ◽

Invasive Cell

Glioblastoma multiforme (GBM) recurrences after temozolomide (TMZ) treatment result from the expansion of drug-resistant and potentially invasive GBM cells. This process is facilitated by O6-Methylguanine-DNA Methyltransferase (MGMT), which counteracts alkylating TMZ activity. We traced the expansion of invasive cell lineages under persistent chemotherapeutic stress in MGMTlow (U87) and MGMThigh (T98G) GBM populations to look into the mechanisms of TMZ-induced microevolution of GBM invasiveness. TMZ treatment induced short-term, pro-invasive phenotypic shifts of U87 cells, in the absence of Snail-1 activation. They were illustrated by a transient induction of their motility and followed by the hypertrophy and the signs of senescence in scarce U87 sub-populations that survived long-term TMZ stress. In turn, MGMThigh T98G cells reacted to the long-term TMZ treatment with the permanent induction of invasiveness. Ectopic Snail-1 down-regulation attenuated this effect, whereas its up-regulation augmented T98G invasiveness. MGMTlow and MGMThigh cells both reacted to the long-term TMZ stress with the induction of Cx43 expression. However, only in MGMThigh T98G populations, Cx43 was directly involved in the induction of invasiveness, as manifested by the induction of T98G invasiveness after ectopic Cx43 up-regulation and by the opposite effect after Cx43 down-regulation. Collectively, Snail-1/Cx43-dependent signaling participates in the long-term TMZ-induced microevolution of the invasive GBM front. High MGMT activity remains a prerequisite for this process, even though MGMT-related GBM chemoresistance is not necessary for its initiation.

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Lobetyolin inhibits the proliferation of breast cancer cells via ASCT2 down-regulation-induced apoptosis

Human & Experimental Toxicology ◽

10.1177/09603271211021476 ◽

2021 ◽

pp. 096032712110214

Author(s):

Yansong Chen ◽

Ye Tian ◽

Gongsheng Jin ◽

Zhen Cui ◽

Wei Guo ◽

...

Keyword(s):

Breast Cancer ◽

Mrna Expression ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Glutamine Metabolism ◽

Down Regulation ◽

Anti Cancer ◽

Induced Apoptosis ◽

Glutamine Uptake

This study aimed to investigate the anti-cancer effect of lobetyolin on breast cancer cells. Lobetyolin was incubated with MDA-MB-231 and MDA-MB-468 breast cancer cells for 24 h. Glucose uptake and the mRNA expression of GLUT4 ( SLC2A4), HK2 and PKM2 were detected to assess the effect of lobetyolin on glucose metabolism. Glutamine uptake and the mRNA expression of ASCT2 ( SLC1A5), GLS1, GDH and GLUL were measured to assess the effect of lobetyolin on glutamine metabolism. Annexin V/PI double staining and Hoechst 33342 staining were used to investigate the effect of lobetyolin on cell apoptosis. Immunoblot was employed to estimate the effect of lobetyolin on the expression of proliferation-related markers and apoptosis-related markers. SLC1A5 knockdown with specific siRNA was performed to study the role of ASCT2 played in the anti-cancer effect of lobetyolin on MDA-MB-231 and MDA-MB-468 breast cancer cells. C-MYC knockdown with specific siRNA was performed to study the role of c-Myc played in lobetyolin-induced ASCT2 down-regulation. Myr-AKT overexpression was performed to investigate the role of AKT/GSK3β signaling played in lobetyolin-induced down-regulation of c-Myc and ASCT2. The results showed that lobetyolin inhibited the proliferation of both MDA-MB-231 and MDA-MB-468 breast cancer cells. Lobetyolin disrupted glutamine uptake via down-regulating ASCT2. SLC1A5 knockdown attenuated the anti-cancer effect of lobetyolin. C-MYC knockdown attenuated lobetyolin-caused down-regulation of ASCT2 and Myr-AKT overexpression reversed lobetyolin-caused down-regulation of both c-Myc and ASCT2. In conclusion, the present work suggested that lobetyolin exerted anti-cancer effect via ASCT2 down-regulation-induced apoptosis in breast cancer cells.

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3,3′-Diindolylmethane Suppresses the Growth of Hepatocellular Carcinoma by Regulating Its Invasion, Migration and ER Stress-Mediated Mitochondrial Apoptosis

Cells ◽

10.3390/cells10051178 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1178

Author(s):

Suvesh Munakarmi ◽

Juna Shrestha ◽

Hyun-Beak Shin ◽

Geum-Hwa Lee ◽

Yeon-Jun Jeong

Keyword(s):

Hepatocellular Carcinoma ◽

Er Stress ◽

Hepatoma Cell ◽

Biologically Active ◽

Migration And Invasion ◽

Therapeutic Effects ◽

Dependent Manner ◽

Mesenchymal Transition ◽

Huh7 Cells ◽

Anti Cancer

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide with limited treatment options. Biomarker-based active phenolic flavonoids isolated from medicinal plants might shed some light on potential therapeutics for treating HCC. 3,3′-diindolylmethane (DIM) is a unique biologically active dimer of indole-3-carbinol (I3C), a phytochemical compound derived from Brassica species of cruciferous vegetables—such as broccoli, kale, cabbage, and cauliflower. It has anti-cancer effects on various cancers such as breast cancer, prostate cancer, endometrial cancer, and colon cancer. However, the molecular mechanism of DIM involved in reducing cancer risk and/or enhancing therapy remains unknown. The aim of the present study was to evaluate anti-cancer and therapeutic effects of DIM in human hepatoma cell lines Hep3B and HuhCell proliferation was measured with MTT and trypan blue colony formation assays. Migration, invasion, and apoptosis were measured with Transwell assays and flow cytometry analyses. Reactive oxygen species (ROS) intensity and the loss in mitochondrial membrane potential of Hep3B and Huh7 cells were determined using dihydroethidium (DHE) staining and tetramethylrhodamine ethyl ester dye. Results showed that DIM significantly suppressed HCC cell growth, proliferation, migration, and invasion in a concentration-dependent manner. Furthermore, DIM treatment activated caspase-dependent apoptotic pathway and suppressed epithelial–mesenchymal transition (EMT) via ER stress and unfolded protein response (UPR). Taken together, our results suggest that DIM is a potential anticancer drug for HCC therapy by targeting ER-stress/UPR.

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