scholarly journals Gemcitabine radiosensitization primes irradiated malignant meningioma cells for senolytic elimination by navitoclax

2021 ◽  
Author(s):  
Masahiro Yamamoto ◽  
Tomomi Sanomachi ◽  
Shuhei Suzuki ◽  
Keita Togashi ◽  
Asuka Sugai ◽  
...  
Keyword(s):  
Apoptotic Cell ◽  
Oxygen Species ◽  
Malignant Meningioma ◽  
Highly Sensitive ◽  
Meningioma Cell ◽  
Aggressive Tumor ◽  
Cell Growth Suppression ◽  
Underlying Mechanisms

Abstract Background Malignant meningioma is an aggressive tumor that requires adjuvant radiotherapy after surgery, yet there has been no standard systemic therapy established so far. We recently reported that malignant meningioma cells are highly sensitive to gemcitabine; however, it remains unknown whether or how gemcitabine interacts with ionizing radiation (IR) in malignant meningioma cells. Methods We examined radiosensitization effects of gemcitabine using malignant meningioma cell lines and xenografts and explored the underlying mechanisms. Results Gemcitabine sensitized malignant meningioma cells to IR through the induction of senescence both in vitro and in vivo. Gemcitabine augmented the intracellular production of reactive oxygen species (ROS) by IR, which, together with cell growth suppression/senescence induced by this combination, was inhibited by N-acetyl-cysteine, suggesting a pivotal role for ROS in these combinatorial effects. Navitoclax, a senolytic drug that inhibits Bcl-2 proteins, further enhanced the effects of the combination of gemcitabine and IR by strongly inducing apoptotic cell death in senescent cells. Conclusion These results not only indicate the potential of gemcitabine as a candidate radiosensitizer for malignant meningioma, but also reveal a novel role for gemcitabine radiosensitization as a means to create a therapeutic vulnerability of senescent meningioma cells to senolytics.

scholarly journals ET-6 Gemcitabine radiosensitization primes irradiated malignant meningioma cells for senolytic elimination by navitoclax

2021 ◽  
Vol 3 (Supplement_6) ◽  
pp. vi4-vi5
Author(s):  
Masahiro Yamamoto ◽  
Chifumi Kitanaka
Keyword(s):  
Intracellular Transport ◽  
Apoptotic Cell ◽  
Single Agent ◽  
Case Series ◽  
Malignant Meningioma ◽  
Phase 2 Clinical Trial ◽  
Cell Growth Suppression ◽  
Underlying Mechanisms

Abstract BACKGROUND: Malignant meningioma is an aggressive tumor that requires adjuvant radiotherapy after surgery, yet there has been no standard systemic therapy established so far. We have demonstrated that malignant meningioma cells are exquisitely sensitive to gemcitabine due to their increased expression of hENT1 and dCK, which play critical roles in the intracellular transport and activation of gemcitabine, respectively (Takeda et al. Oncotarget 8:90996, 2017; Yamamoto et al., Neuro-Oncol 23:945, 2021). Significantly, in support of our findings, the efficacy and safety of gemcitabine have recently been documented in a small case series of patients with recurrent meningiomas, which has further led to a phase 2 clinical trial to evaluate the efficacy of gemcitabine in recurrent high-grade meningiomas (Khaddar et al., South Asian J Cancer 9:261, 2020). Besides its efficacy as a single agent, gemcitabine reportedly has a radiosensitizing effect in pancreatic cancer. However, it remains unknown whether or how gemcitabine interacts with ionizing radiation (IR) in malignant meningioma cells. METHODS: We examined radiosensitization effects of gemcitabine using malignant meningioma cell lines and xenografts (s.c. and i.c.) and explored the underlying mechanisms. RESULTS: Gemcitabine sensitized malignant meningioma cells remarkably to IR through the induction of senescence both in vitro and in vivo. Gemcitabine augmented the intracellular production of reactive oxygen species (ROS) by IR, which, together with cell growth suppression/senescence induced by this combination, was inhibited by N-acetyl-cysteine, suggesting a pivotal role for ROS in these combinatorial effects. Navitoclax, a senolytic drug, further enhanced the effects of the combination of gemcitabine and IR in vitro and in vivo by strongly inducing apoptotic cell death in senescent cells. CONCLUSION: These results suggest that gemcitabine is not only a promising radiosensitizer for malignant meningioma but also creates in combination with IR a therapeutic vulnerability of senescent meningioma cells to senolytics. (submitted for publication)

Irinotecan: a potential new chemotherapeutic agent for atypical or malignant meningiomas

2007 ◽  
Vol 106 (3) ◽  
pp. 455-462 ◽  
Author(s):  
Vinay Gupta ◽  
Yuzhuang S. Su ◽  
Christian G. Samuelson ◽  
Leonard F. Liebes ◽  
Marc C. Chamberlain ◽  
...  
Keyword(s):  
Cell Line ◽  
Topoisomerase I ◽  
Cellular Proliferation ◽  
Apoptotic Cell ◽  
Tumor Model ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Malignant Meningioma ◽  
Meningioma Cell

Object There is currently no effective chemotherapy for meningiomas. Although most meningiomas are treated surgically, atypical or malignant meningiomas and surgically inaccessible meningiomas may not be removed completely. The authors have investigated the effects of the topoisomerase I inhibitor irinotecan (CPT-11) on primary meningioma cultures and a malignant meningioma cell line in vitro and in vivo. Methods The effects of irinotecan on cellular proliferation in primary meningioma cultures and the IOMM-Lee malignant meningioma cell line were measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay and flow cytometry. Apoptosis following drug treatment was evaluated by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and the DNA laddering assays. The effects of irinotecan in vivo on a meningioma model were determined with a subcutaneous murine tumor model using the IOMM-Lee cell line. Irinotecan induced a dose-dependent antiproliferative effect with subsequent apoptosis in the primary meningioma cultures (at doses up to 100 μM) as well as in the IOMM-Lee human malignant meningioma cell line (at doses up to 20 μM) irinotecan. In the animal model, irinotecan treatment led to a statistically significant decrease in tumor growth that was accompanied by a decrease in Bcl-2 and survivin levels and an increase in apoptotic cell death. Conclusions Irinotecan demonstrated growth-inhibitory effects in meningiomas both in vitro and in vivo. Irinotecan was much more effective against the malignant meningioma cell line than against primary meningioma cultures. Therefore, this drug may have an important therapeutic role in the treatment of atypical or malignant meningiomas and should be evaluated further for this purpose.

scholarly journals Preventive Effect of Dihydromyricetin against Cisplatin-Induced NephrotoxicityIn VitroandIn Vivo

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Fei Wu ◽  
Yi Li ◽  
Haibo Song ◽  
Yuan Zhang ◽  
Yuzhu Zhang ◽  
...  
Keyword(s):  
Structural Damage ◽  
Apoptotic Cell ◽  
Severe Side Effect ◽  
Preventive Effect ◽  
Chemotherapy Drugs ◽  
Antioxidative Effects ◽  
Underlying Mechanisms ◽  
Ampelopsis Grossedentata

Nephrotoxicity is a frequent severe side effect of cisplatin chemotherapy, limiting its clinical use despite being one of the most potent chemotherapy drugs. Dihydromyricetin is a highly abundant compound purified from the leaves ofAmpelopsis grossedentata. Previous studies have demonstrated the anti-inflammatory and antioxidative effects of Dihydromyricetin bothin vitroandin vivo, but little is known about the effects of Dihydromyricetin on cisplatin-induced nephrotoxicity and its underlying mechanisms. In the present study, we investigated its potential renoprotective effect and found that Dihydromyricetin ameliorated the renal functional impairment and structural damage caused by cisplatin. Moreover, Dihydromyricetin markedly attenuated cisplatin-induced oxidative stress, as well as protecting against cisplatin-induced inflammation and apoptotic cell death in mouse kidney tissues. These results collectively highlight the potential of DMY as a rational renoprotective agent against cisplatin.

scholarly journals In vitro effect of N-acetylcysteine on hepatocyte injury caused by dichlorodiphenyltrichloroethane and its metabolites

2013 ◽  
Vol 33 (1) ◽  
pp. 41-53 ◽  
Author(s):  
J J van Tonder ◽  
M Gulumian ◽  
A D Cromarty ◽  
V Steenkamp
Keyword(s):  
Apoptotic Cell ◽  
Ros Generation ◽  
Oxygen Species ◽  
Cellular Viability ◽  
Cytotoxic Effects ◽  
Hepatocyte Injury ◽  
Intracellular Changes ◽  
Vitro Effect

The organochlorine pesticide, dichlorodiphenyltrichloroethane (DDT), is still used to combat the spread of malaria in several developing countries despite its accumulation and known hepatotoxic effects that have been demonstrated both in vitro and in vivo. N-Acetylcysteine (NAC) is a recognized hepatoprotective agent that has been reported to reduce hepatotoxicity initiated by many different compounds. The aim of this study was to determine whether NAC could counter in vitro hepatocyte injury induced by DDT or its two major metabolites, dichlorodiphenyldichloroethylene and dichlorodiphenyldichloroethane. HepG2 cell cultures were used to assess the following parameters of toxicity: cellular viability, intracellular levels of reactive oxygen species (ROS), mitochondrial membrane potential and initiation of apoptosis. None of the three test compounds induced ROS generation, yet exposure to any of the three compounds produced mitochondrial hyperpolarization, which was countered by NAC pretreatment. All three test compounds also induced apoptotic cell death, which was inhibited by NAC. Despite NAC counteracting some adverse intracellular changes due to organochlorine exposure, it appeared to aggravate the cytotoxic effects of the organochlorine compounds at low test concentrations. As the same outcome may also occur in vivo, results from the present study raise concern about the use of NAC as treatment for DDT-induced hepatotoxicity.

Hyperlipidemia Impairs Osseointegration via the ROS/Wnt/β-Catenin Pathway

2021 ◽  
pp. 002203452098324
Author(s):  
Y.N. Wang ◽  
T.T. Jia ◽  
Y. Feng ◽  
S.Y. Liu ◽  
W.J. Zhang ◽  
...  
Keyword(s):  
Titanium Surface ◽  
Titanium Implant ◽  
Titanium Implants ◽  
Oxygen Species ◽  
High Fat ◽  
Promising Therapeutic Target ◽  
Novel Drugs ◽  
Underlying Mechanisms

The influence of hyperlipidemia on titanium implant osseointegration and the underlying mechanisms is not well understood. This study investigates the changes in osseointegration and explores the potential mechanisms in hyperlipidemia conditions. In vivo, specialized titanium implants were implanted in the femurs of diet-induced or genetic hyperlipidemia mice. In vitro, primary murine osteoblasts were cultured on the titanium surface in high-fat medium. Results showed that hyperlipidemia led to poor osseointegration in both types of mice in vivo, and high-fat medium impaired the osteogenic differentiation of primary osteoblasts on the titanium surface in vitro. In addition, high-fat medium caused significant overproduction of reactive oxygen species (ROS) and inhibition of the Wnt/β-catenin pathway in osteoblasts. Both N-acetyl-L-cysteine (NAC, an ROS antagonist) and Wnt3a (an activator of the Wnt/β-catenin pathway) attenuated the poor osteogenic ability of osteoblasts. In addition, NAC reactivated the Wnt/β-catenin pathway in osteoblasts under high-fat stimulation. These results demonstrate that hyperlipidemia impairs osseointegration via the ROS/Wnt/β-catenin pathway and provide support for the ROS or Wnt/β-catenin pathway as a promising therapeutic target for the development of novel drugs or implant materials to improve the osseointegration of implants in hyperlipidemic patients.

Anti-Angiongenic Effects of mTOR-Inhibitors Is Regulated by AKT Activity in Multiple Myeloma Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3406-3406
Author(s):  
Patrick Frost ◽  
Bao Hoang ◽  
Yijiang Shi ◽  
Huajun Yan ◽  
Alan Lichtenstein
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Apoptotic Cell ◽  
Mammalian Target Of Rapamycin ◽  
Hypoxia Inducible Factor ◽  
Mtor Inhibitors ◽  
Underlying Mechanisms ◽  
Salvage Pathways

Abstract Inhibitors of the mammalian target of rapamycin (mTOR), such as rapamycin (RAPA) and CCI-779 (CCI), have potential as anti-tumor agents against multiple myeloma (MM). Since other tumor models have demonstrated that heightened AKT activity induces hypersensitivity to mTOR inhibitors, we stably transfected U266 human MM cells with a constitutively activated AKT allele (U266-AKT) or empty vector control (U266-EV) in order to further explore the underlying mechanisms of this phenomena. Analysis of cell death demonstrated that U266-AKT were significantly more sensitive to RAPA in vitro, with an ED50 of 0.01 nM versus an ED50 of >100 nM for U266-EV control cells. A similar alteration of sensitivity to CCI was demonstrated in U266 isogenic tumors grown in NOD/SCID mice and treated with CCI in vivo. Analysis of the excised tumor nodules demonstrated a >5 fold inclease in apoptotic nuclei in U266-AKT tumors treated with CCI compared to isogenic control tumors, despite previous reports that mTOR inhibitors do not induce apoptosis in MM cells in vitro. One potential explanation for this is that AKT regulates the ability of CCI to inhibit angiogenesis, which is only relevent in vivo, and thereby indirectly induces apoptotic cell death. In support of this hypothesis, we demonstrated that CCI significantly decreased angiogenesis (measued by in situ staining of excised tumor nodules with CD34, a marker for endothelial cells) by 80% in U266-AKT, and only by 67% in isogenic controls. Since previous studies demonstrated that AKT/mTOR regulates the expression of vascular endothelial growth factor (VEGF) and hypoxia inducible factor 1a (HIF1a), we hypothesized that MM cells with heightened AKT activity may be more sensitive to the CCI-mediated inhibition of these critical angiogenic factors. In vitro, RAPA was markedly more effective at inhibiting HIF-1a and VEGF expression from U266-AKT compared to U266-EV control cells. One possible explanation for the regulatory role of AKT in the RAPA/CCI response is that MM cells with hyperactive AKT function depend upon mTOR-mediated (i.e. cap-dependent) translational pathway to express critical proteins like VEGF and HIF-1a, while “low-AKT” MM cells may be able to utilize non-mTOR dependent (i.e. cap-independent) salvage pathways to express these critical proteins and are thereby resistant to mTOR inhibitors.

Phytosomal Curcumin Elicits Anti-tumor Properties Through Suppression of Angiogenesis, Cell Proliferation and Induction of Oxidative Stress in Colorectal Cancer

2019 ◽  
Vol 24 (39) ◽  
pp. 4626-4638 ◽  
Author(s):  
Reyhaneh Moradi-Marjaneh ◽  
Seyed M. Hassanian ◽  
Farzad Rahmani ◽  
Seyed H. Aghaee-Bakhtiari ◽  
Amir Avan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Colorectal Cancer ◽  
Therapeutic Potential ◽  
Vegf Signaling ◽  
Anticancer Effects ◽  
Inhibition Of Angiogenesis ◽  
Underlying Mechanisms ◽  
Apoptotic Activity

Background: Colorectal cancer (CRC) is one of the most common causes of cancer-associated mortality in the world. Anti-tumor effect of curcumin has been shown in different cancers; however, the therapeutic potential of novel phytosomal curcumin, as well as the underlying molecular mechanism in CRC, has not yet been explored. Methods: The anti-proliferative, anti-migratory and apoptotic activity of phytosomal curcumin in CT26 cells was assessed by MTT assay, wound healing assay and Flow cytometry, respectively. Phytosomal curcumin was also tested for its in-vivo activity in a xenograft mouse model of CRC. In addition, oxidant/antioxidant activity was examined by DCFH-DA assay in vitro, measurement of malondialdehyde (MDA), Thiol and superoxidedismutase (SOD) and catalase (CAT) activity and also evaluation of expression levels of Nrf2 and GCLM by qRT-PCR in tumor tissues. In addition, the effect of phytosomal curcumin on angiogenesis was assessed by the measurement of VEGF-A and VEGFR-1 and VEGF signaling regulatory microRNAs (miRNAs) in tumor tissue. Results: Phytosomal curcumin exerts anti-proliferative, anti-migratory and apoptotic activity in-vitro. It also decreases tumor growth and augmented 5-fluorouracil (5-FU) anti-tumor effect in-vivo. In addition, our data showed that induction of oxidative stress and inhibition of angiogenesis through modulation of VEGF signaling regulatory miRNAs might be underlying mechanisms by which phytosomal curcumin exerted its antitumor effect. Conclusion: Our data confirmed this notion that phytosomal curcumin administrates anticancer effects and can be used as a complementary treatment in clinical settings.

Novel Findings of Anti-cancer Property of Propofol

2018 ◽  
Vol 18 (2) ◽  
pp. 156-165 ◽  
Author(s):  
Jiaqiang Wang ◽  
Chien-shan Cheng ◽  
Yan Lu ◽  
Xiaowei Ding ◽  
Minmin Zhu ◽  
...  
Keyword(s):  
General Anesthesia ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Intravenous Anesthetic ◽  
The Past ◽  
Anti Cancer ◽  
Underlying Mechanisms ◽  
Recent Attention

Background: Propofol, a widely used intravenous anesthetic agent, is traditionally applied for sedation and general anesthesia. Explanation: Recent attention has been drawn to explore the effect and mechanisms of propofol against cancer progression in vitro and in vivo. Specifically, the proliferation-inhibiting and apoptosis-inducing properties of propofol in cancer have been studied. However, the underlying mechanisms remain unclear. Conclusion: This review focused on the findings within the past ten years and aimed to provide a general overview of propofol's malignance-modulating properties and the potential molecular mechanisms.

Studies on the mechanism of acute inhibition of thyroglobulin hydrolysis by iodine

1985 ◽  
Vol 108 (4) ◽  
pp. 511-517 ◽  
Author(s):  
Nandalal Bagchi ◽  
Birdie Shivers ◽  
Thomas R. Brown
Keyword(s):  
Time Course ◽  
Period 2 ◽  
Iodotyrosine Deiodinase ◽  
Rate Of Hydrolysis ◽  
Underlying Mechanisms ◽  
Excess Iodide ◽  
Sites Of Action ◽  
Hydrolysis Of

Abstract. Iodine in excess is known to acutely inhibit thyroidal secretion. In the present study we have characterized the time course of the iodine effect in vitro and investigated the underlying mechanisms. Labelled thyroid glands were cultured in vitro in medium containing mononitrotyrosine, an inhibitor of iodotyrosine deiodinase. The rate of hydrolysis of labelled thyroglobulin was measured as the proportion of labelled iodotyrosines and iodothyronines recovered at the end of culture and was used as an index of thyroidal secretion. Thyrotrophin (TSH) administered in vivo acutely stimulated the rate of thyroglobulin hydrolysis. Addition of Nal to the culture medium acutely inhibited both basal and TSH-stimulated thyroglobulin hydrolysis. The effect of iodide was demonstrable after 2 h, maximal after 6 h and was not reversible upon removal of iodide. Iodide abolished the dibutyryl cAMP induced stimulation of thyroglobulin hydrolysis. Iodide required organic binding of iodine for its effect but new protein or RNA synthesis was not necessary. The inhibitory effects of iodide and lysosomotrophic agents such as NH4C1 and chloroquin on thyroglobulin hydrolysis were additive suggesting different sites of action. Iodide added in vitro altered the distribution of label in prelabelled thyroglobulin in a way that suggested increased coupling in the thyroglobulin molecule. These data indicate that 1) the iodide effect occurs progressively over a 6 h period, 2) continued presence of iodide is not necessary once the inhibition is established, 3) iodide exerts its action primarily at a post cAMP, prelysosomal site and 4) the effect requires organic binding of iodine, but not new RNA or protein synthesis. Our data are consistent with the hypothesis that excess iodide acutely inhibits thyroglobulin hydrolysis by increasing the resistance of thyroglobulin to proteolytic degradation through increased iodination and coupling.

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