RB1 loss triggers dependence on ESRRG in retinoblastoma

Retinoblastoma (Rb) is a deadly childhood eye cancer that is classically initiated by inactivation of the RB1 tumor suppressor. Clinical management continues to rely on nonspecific chemotherapeutic agents that are associated with treatment resistance and toxicity. Here, we analyzed 103 whole exomes, 16 whole transcriptomes, 5 single-cell transcriptomes, and 4 whole genomes from primary Rb tumors to identify novel Rb dependencies. Several recurrent genomic aberrations implicate estrogen-related receptor gamma (ESRRG) in Rb pathogenesis. RB1 directly interacts with and inhibits ESRRG, and RB1 loss uncouples ESRRG from negative regulation. ESRRG regulates genes involved in retinogenesis and oxygen metabolism in Rb cells. ESRRG is preferentially expressed in hypoxic Rb cells in vivo. Depletion or inhibition of ESRRG causes marked Rb cell death which is exacerbated in hypoxia. These findings reveal a novel dependency of Rb cells on ESRRG, and they implicate ESRRG as a potential therapeutic vulnerability in Rb.

Download Full-text

Self-amplification of oxidative stress with tumour microenvironment-activatable iron-doped nanoplatform for targeting hepatocellular carcinoma synergistic cascade therapy and diagnosis

Journal of Nanobiotechnology ◽

10.1186/s12951-021-01102-0 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Qiao-Mei Zhou ◽

Yuan-Fei Lu ◽

Jia-Ping Zhou ◽

Xiao-Yan Yang ◽

Xiao-Jie Wang ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Hepatocellular Carcinoma ◽

Hydrogen Peroxide ◽

Cell Death ◽

Magnetic Resonance ◽

Tumour Microenvironment ◽

Chemotherapeutic Agents ◽

Resonance Imaging

Abstract Background Hepatocellular carcinoma is insensitive to many chemotherapeutic agents. Ferroptosis is a form of programmed cell death with a Fenton reaction mechanism. It converts endogenous hydrogen peroxide into highly toxic hydroxyl radicals, which inhibit hepatocellular carcinoma progression. Methods The morphology, elemental composition, and tumour microenvironment responses of various organic/inorganic nanoplatforms were characterised by different analytical methods. Their in vivo and in vitro tumour-targeting efficacy and imaging capability were analysed by magnetic resonance imaging. Confocal microscopy, flow cytometry, and western blotting were used to investigate the therapeutic efficacy and mechanisms of complementary ferroptosis/apoptosis mediated by the nanoplatforms. Results The nanoplatform consisted of a silica shell doped with iron and disulphide bonds and an etched core loaded with doxorubicin that generates hydrogen peroxide in situ and enhances ferroptosis. It relied upon transferrin for targeted drug delivery and could be activated by the tumour microenvironment. Glutathione-responsive biodegradability could operate synergistically with the therapeutic interaction between doxorubicin and iron and induce tumour cell death through complementary ferroptosis and apoptosis. The nanoplatform also has a superparamagnetic framework that could serve to guide and monitor treatment under T2-weighted magnetic resonance imaging. Conclusion This rationally designed nanoplatform is expected to integrate cancer diagnosis, treatment, and monitoring and provide a novel clinical antitumour therapeutic strategy. Graphical Abstract

Download Full-text

DDIS-06. ANTICANCER EFFECTS OF THE SMALL MOLECULE INHIBITOR SB747651A IN GLIOBLASTOMAS

Neuro-Oncology ◽

10.1093/neuonc/noz175.266 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi66-vi66

Author(s):

Arnon Knudsen ◽

Henning B Boldt ◽

Bjarne Kristensen

Keyword(s):

Cell Death ◽

Cell Cultures ◽

Small Molecule ◽

Treatment Resistance ◽

Small Molecule Inhibitor ◽

In Vivo Studies ◽

Anticancer Effects ◽

Molecule Inhibitor ◽

Dose Dependent

Abstract INTRODUCTION Most glioblastomas harbor several different genetic alterations in major cell signaling pathways, leading to tumor progression and treatment resistance. Single-targeted therapies against these alterations have thus far failed to show major clinical value. The aim of this study was to investigate the anticancer effects of SB747651A, a multi-target small molecule inhibitor, targeting the RAS-MAPK and AKT-PI3K kinases AKT, MSK1/2, RSK1/2 and p70S6K in glioblastomas. METHODS Three patient-derived glioblastoma cultures were grown as free-floating spheroids and treated with 5 or 10 µM SB747651A. Exposed cells were subject to assays investigating cell viability (propidium iodide), apoptosis (Caspase 3/7), spheroid formation capacity, chemo sensitivity (temozolomide), and migration. In vivo studies are currently ongoing. RESULTS Exposed cells showed increased cell death and apoptosis across all three cell cultures in a dose-dependent manner vs. controls (P=0.001). Combination treatment with SB747651A and temozolomide resulted in a significant dose-dependent synergistic effect on cell death in all cell cultures. The fraction of spheroid-initiating cells was significantly reduced in exposed cells (1 in 12 cells) compared to controls (1 in 5 cells; P=0.001), and the growth rate of treated tumor spheroids was reduced by up to 47% (P=0.001). Exposed spheroids showed reduced cell migration in 2 of 3 cell lines, with a maximum reduction of migration distance by 60.4% (P=0.001). CONCLUSION SB747651A treatment has shown promising in vitro results by targeting mechanisms with high relevance for the progression and treatment resistance of glioblastomas. Ongoing in vivo studies are aiming to validate these findings, and to uncover potential use of SB747651A in the clinical setting.

Download Full-text

Mitochondrial metabolic reprogramming controls the induction of immunogenic cell death and efficacy of chemotherapy in bladder cancer

Science Translational Medicine ◽

10.1126/scitranslmed.aba6110 ◽

2021 ◽

Vol 13 (575) ◽

pp. eaba6110

Author(s):

Bianca Oresta ◽

Chiara Pozzi ◽

Daniele Braga ◽

Rodolfo Hurle ◽

Massimo Lazzeri ◽

...

Keyword(s):

Bladder Cancer ◽

Cell Death ◽

Complex I ◽

Dendritic Cell Maturation ◽

Chemotherapeutic Agents ◽

Metabolic Reprogramming ◽

Immunogenic Cell Death ◽

Treatment Schedule ◽

Cancer Management

Although chemotherapeutic agents have been used for decades, the mechanisms of action, mechanisms of resistance, and the best treatment schedule remain elusive. Mitomycin C (MMC) is the gold standard treatment for non–muscle-invasive bladder cancer (NMIBC). However, it is effective only in a subset of patients, suggesting that, aside from cytotoxicity, other mechanisms could be involved in mediating the success of the treatment. Here, we showed that MMC promotes immunogenic cell death (ICD) and in vivo tumor protection. MMC-induced ICD relied on metabolic reprogramming of tumor cells toward increased oxidative phosphorylation. This favored increased mitochondrial permeability leading to the cytoplasmic release of mitochondrial DNA, which activated the inflammasome for efficient IL-1β (interleukin-1β) secretion that promoted dendritic cell maturation. Resistance to ICD was associated with mitochondrial dysfunction related to low abundance of complex I of the respiratory chain. Analysis of complex I in patient tumors indicated that low abundance of this mitochondrial complex was associated with recurrence incidence after chemotherapy in patients with NMIBC. The identification of mitochondria-mediated ICD as a mechanism of action of MMC offers opportunities to optimize bladder cancer management and provides potential markers of treatment efficacy that could be used for patient stratification.

Download Full-text

CircDTL Functions as an Oncogene and Regulates Both Apoptosis and Ferroptosis in Non-small Cell Lung Cancer Cells

Frontiers in Genetics ◽

10.3389/fgene.2021.743505 ◽

2021 ◽

Vol 12 ◽

Author(s):

Wang Shanshan ◽

Ma Hongying ◽

Fang Jingjing ◽

Yu Yiming ◽

Ren Yu ◽

...

Keyword(s):

Lung Cancer ◽

Cell Death ◽

Small Cell Lung Cancer ◽

Cell Lung Cancer ◽

Chemotherapeutic Agents ◽

Small Cell ◽

Migration And Invasion ◽

Circular Rnas ◽

Small Cell Lung

Background: Circular RNAs (circRNA) play an essential role in the tumorigenesis of non-small cell lung cancer (NSCLC). CircDTL is a novel identified circRNA with little information regarding its biological role. However, the role of circDTL in NSCLC has not been investigated yet.Method: In this study, the levels of circDTL in tissues and cells were measured by RT-PCR. Cell viability was measured by the CCK-8 assay. Cell migration and invasion were evaluated using the wound healing assay and transwell assay, respectively. Cell death was measured by the cell death ELISA kit. The levels of Fe2+, ROS, MDA and GSH were measured using the commercial kits. The interactions between miR-1287-5p and circDTL/3′UTR GPX4 were verified by dual-luciferase activity assay. The effects of circDTL on tumor growth were evaluated in vivo.Results: CircDTL was found to be upregulated and acted as an oncogene in NSCLC cells. Knockdown of circDTL promoted both apoptosis and ferroptosis of NSCLC cells. It was identified that circDTL exerts its oncogenic effects via the circDTL/miR-1287-5p/GPX4 axis and GPX4 inhibits both ferroptosis and apoptosis. Finally, this study showed that silencing of circDTL promoted the sensitivity of NSCLC cells to chemotherapeutic agents and inhibited the growth of tumors in vivo.Conclusion: CircDTL acts as an oncogene and exerts its effects via the miR-1287-5p/GPX4 axis in NSCLC, providing a potential therapeutic target for NSCLC cancer therapy.

Download Full-text

Radotinib Enhances Cytarabine (Ara-C)-Induced Acute Myeloid Leukemia Cell Death

10.21203/rs.3.rs-48479/v1 ◽

2020 ◽

Author(s):

Sook-Kyoung Heo ◽

Eui-Kyu Noh ◽

Ho-Min Yu ◽

Do Kyoung Kim ◽

Hye Jin Seo ◽

...

Keyword(s):

Cell Cycle ◽

Cell Death ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Caspase 3 ◽

Annexin V ◽

Chemotherapeutic Agents ◽

Cell Cycle Distribution ◽

Acute Myeloid

Abstract Background: Acute myeloid leukemia (AML) is a heterogeneous disease that frequently relapses after standard chemotherapy. Therefore, there is a need for the development of novel chemotherapeutic agents that could treat AML effectively. Radotinib, an oral BCR-ABL tyrosine kinase inhibitor, was developed as a drug for the treatment of chronic myeloid leukemia. Previously, we reported that radotinib exerts increased cytotoxic effects towards AML cells. However, little is known about the effects of combining radotinib with Ara-C, a conventional chemotherapeutic agent for AML, with respect to cell death and cell cycle distribution in AML cells. Methods: Synergistic anti-cancer effects of radotinib and Ara-C in AML cells including HL60, HEL92.1.7, THP-1 and bone marrow cells from AML patients have been examined. Diverse cell biological assays such as cell viability assay, Annexin V-positive cells, caspase-3 activity, cell cycle distribution, and related signaling pathway have been performed. We also confirmed synergistic effects of radotinib and Ara-C on the xenograft model in vivo. Results: The combination of radotinib and Ara-C was found to induce AML cell apoptosis, which involved the mitochondrial pathway. In brief, combined radotinib and Ara-C significantly induced Annexin V-positive cells, cytosolic cytochrome C, and the pro-apoptotic protein Bax in AML cells including HL60, HEL92.1.7, and THP-1. In addition, mitochondrial membrane potential and Bcl-xl protein were markedly decreased by radotinib and Ara-C. Moreover, this combination induced caspase-3 activity. Cleaved caspase-3, 7, and 9 levels were also increased by combined radotinib and Ara-C. Additionally, radotinib and Ara-C co-treatment induced G0/G1 arrest via the induction of CDKIs such as p21 and p27 and the inhibition of CDK2 and cyclin E. Thus, radotinib/Ara-C induces mitochondrial-dependent apoptosis and G0/G1 arrest via the regulation of the CDKI–CDK–cyclin cascade in AML cells. In addition, our results showed that combined treatment with radotinib and Ara-C inhibits AML cell growth, including tumor volumes and weights in vivo. Also, the combination of radotinib and Ara-C can sensitize cells to chemotherapeutic agents such as daunorubicin or idarubicin in AML cells. Conclusions: Therefore, our results can be concluded that radotinib in combination with Ara-C possesses a strong anti-AML activity.

Download Full-text

Glial cytotoxicity of low doses of cadmium as a model of heavy metal pollution influence on vertebrates

Ecology and Noospherology ◽

10.15421/032001 ◽

2020 ◽

Vol 31 (1) ◽

pp. 3-10

Author(s):

V. S. Nedzvetsky ◽

V. Ya. Gasso ◽

A. M. Hahut ◽

I. A. Hasso

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Programmed Cell Death ◽

Oxidative Damage ◽

Cadmium Chloride ◽

Glioma Cells ◽

Low Doses ◽

Genotoxic Effects ◽

Cadmium Ions

Cadmium is a common transition metal that entails an extremely wide range of toxic effects in humans and animals. The cytotoxicity of cadmium ions and its compounds is due to various genotoxic effects, including both DNA damage and chromosomal aberrations. Some bone diseases, kidney and digestive system diseases are determined as pathologies that are closely associated with cadmium intoxication. In addition, cadmium is included in the list of carcinogens because of its ability to initiate the development of tumors of several forms of cancer under conditions of chronic or acute intoxication. Despite many studies of the effects of cadmium in animal models and cohorts of patients, in which cadmium effects has occurred, its molecular mechanisms of action are not fully understood. The genotoxic effects of cadmium and the induction of programmed cell death have attracted the attention of researchers in the last decade. In recent years, the results obtained for in vivo and in vitro experimental models have shown extremely high cytotoxicity of sublethal concentrations of cadmium and its compounds in various tissues. One of the most studied causes of cadmium cytotoxicity is the development of oxidative stress and associated oxidative damage to macromolecules of lipids, proteins and nucleic acids. Brain cells are most sensitive to oxidative damage and can be a critical target of cadmium cytotoxicity. Thus, oxidative damage caused by cadmium can initiate genotoxicity, programmed cell death and inhibit their viability in the human and animal brains. To test our hypothesis, cadmium cytotoxicity was assessed in vivo in U251 glioma cells through viability determinants and markers of oxidative stress and apoptosis. The result of the cell viability analysis showed the dose-dependent action of cadmium chloride in glioma cells, as well as the generation of oxidative stress (p <0.05). Calculated for 48 hours of exposure, the LD50 was 3.1 μg×ml-1. The rates of apoptotic death of glioma cells also progressively increased depending on the dose of cadmium ions. A high correlation between cadmium concentration and apoptotic response (p <0.01) was found for cells exposed to 3–4 μg×ml-1 cadmium chloride. Moreover, a significant correlation was found between oxidative stress (lipid peroxidation) and induction of apoptosis. The results indicate a strong relationship between the generation of oxidative damage by macromolecules and the initiation of programmed cell death in glial cells under conditions of low doses of cadmium chloride. The presented results show that cadmium ions can induce oxidative damage in brain cells and inhibit their viability through the induction of programmed death. Such effects of cadmium intoxication can be considered as a model of the impact of heavy metal pollution on vertebrates.

Download Full-text