scholarly journals V-ATPase as a mediator of treatment resistance in Glioblastoma Multiforme: an in vitro study to investigate new therapeutic strategies

2021 ◽  
Vol 4 (s1) ◽  
Author(s):  
Eleonora Messuti ◽  
Martina Giambra ◽  
Serena Redaelli ◽  
Andrea Di Cristofori ◽  
Carlo Giussani ◽  
...  
Keyword(s):  
Glioblastoma Multiforme ◽  
Chemotherapeutic Agent ◽  
Combined Treatment ◽  
Primary Cultures ◽  
Treatment Resistance ◽  
Glioma Stem Cell ◽  
Bafilomycin A1 ◽  
Atpase Inhibitor ◽  
In Vitro Effects

Recent evidences suggest the involvement of the Vacuolar H+ ATPase (V-ATPase) in the development and/or progression of Glioblastoma Multiforme (GBM). This proton pump could be a valid therapeutic target but more in-depth studies are necessary. The aim of this study is to better define the in vitro effects on Glioma Stem Cell (GSC) primary cultures viability of single and combined treatment with Bafilomycin-A1 (Baf-A1), a V-ATPase inhibitor, and Temozolomide (TMZ), the chemotherapeutic agent currently used to treat GBM patients. We found out that GSC were resistant to TMZ and more sensitive to treatments with Baf-A1 and that the two drugs exerted a synergistic effect when administered together.

scholarly journals Lomeguatrib Increases the Radiosensitivity of MGMT Unmethylated Human Glioblastoma Multiforme Cell Lines

2021 ◽  
Vol 22 (13) ◽  
pp. 6781
Author(s):  
Anna Kirstein ◽  
Daniela Schilling ◽  
Stephanie E. Combs ◽  
Thomas E. Schmid
Keyword(s):  
Glioblastoma Multiforme ◽  
Cell Lines ◽  
Dna Methyltransferase ◽  
Treatment Options ◽  
Treatment Resistance ◽  
Cell Cycle Distribution ◽  
Human Glioblastoma ◽  
Human Glioblastoma Multiforme ◽  
Mgmt Protein

Background: Treatment resistance of glioblastoma multiforme to chemo- and radiotherapy remains a challenge yet to overcome. In particular, the O6-methylguanine-DNA-methyltransferase (MGMT) promoter unmethylated patients have only little benefit from chemotherapy treatment using temozolomide since MGMT counteracts its therapeutic efficacy. Therefore, new treatment options in radiotherapy need to be developed to inhibit MGMT and increase radiotherapy response. Methods: Lomeguatrib, a highly specific MGMT inhibitor, was used to inactivate MGMT protein in vitro. Radiosensitivity of established human glioblastoma multiforme cell lines in combination with lomeguatrib was investigated using the clonogenic survival assay. Inhibition of MGMT was analyzed using Western Blot. Cell cycle distribution and apoptosis were investigated to determine the effects of lomeguatrib alone as well as in combination with ionizing radiation. Results: Lomeguatrib significantly decreased MGMT protein and reduced radiation-induced G2/M arrest. A radiosensitizing effect of lomeguatrib was observed when administered at 1 µM and increased radioresistance at 20 µM. Conclusion: Low concentrations of lomeguatrib elicit radiosensitization, while high concentrations mediate a radioprotective effect.

Differential in vitro effects of chemotherapeutic agents on primary cultures of human ovarian carcinoma

2004 ◽  
Vol 14 (4) ◽  
pp. 607-615 ◽  
Author(s):  
P. Kornblith ◽  
R. L. Ochs ◽  
A. Wells ◽  
M. J. Gabrin ◽  
J. Piwowar ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cultured Cells ◽  
Primary Cultures ◽  
Human Tumor ◽  
Clinical Results ◽  
Chemotherapeutic Agents ◽  
Primary Ovarian Cancer ◽  
In Vitro Effects ◽  
Therapeutic Decision Making

The treatment of ovarian cancer principally relies on the use of platinum and taxane chemotherapeutic agents. Short-term clinical results have been encouraging, but long-term responses remain limited. In this report, an in vitro assay system that utilizes cells grown from human tumor explants has been used to quantitatively evaluate responses to relevant concentrations of alternative chemotherapeutic agents. The results suggest that there are significant differences in the responses of explant-derived cultured cells to the different agents tested. In an evaluation of 276 primary ovarian cancer specimens, five nonstandard drugs were tested in 51 cases. Of these 51 cases, cyclophosphamide had the highest rate of response at 67%, followed by doxorubicin at 61%, gemcitabine at 49%, etoposide at 48%, and topotecan at 14%. Venn diagrams, representing the in vitro responses to the platins and taxanes, as well as the responses to the nonstandard drugs, illustrate that there clearly are distinct differences among patients in a given population. These data underscore the potential importance of evaluating each patient's response to a number of different drugs to optimize the therapeutic decision-making process.

scholarly journals Prolactin (PRL)-Releasing Peptide Stimulates PRL Secretion from Human Fetal Pituitary Cultures and Growth Hormone Release from Cultured Pituitary Adenomas1

2001 ◽  
Vol 86 (6) ◽  
pp. 2826-2830 ◽  
Author(s):  
Tami Rubinek ◽  
Moshe Hadani ◽  
Gad Barkai ◽  
Shlomo Melmed ◽  
Ilan Shimon
Keyword(s):  
Primary Cultures ◽  
Pituitary Hormones ◽  
Pituitary Cells ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Human Pituitary ◽  
Cell Adenoma ◽  
In Vitro Effects

The hypothalamic peptide PRL-releasing peptide (PrRP) has recently been cloned and identified as a ligand of an orphan pituitary receptor that stimulates in vitro PRL secretion. PrRP also induces PRL release in rats in vivo, especially in normal cycling females. However, no information on the effects of PrRP in the human is available. To elucidate the role of PrRP in regulating human anterior pituitary hormones, we used human PrRP-31 in primary cultures of human pituitary tissues, including fetal (20–27 weeks gestation) and normal adult pituitaries, as well as PRL- and GH-secreting adenomas. PrRP increased PRL secretion from human fetal pituitary cultures in a dose-dependent manner by up to 35% (maximal effect achieved with 10 nm), whereas TRH was slightly more potent for PRL release. Coincubation with estradiol resulted in enhanced fetal PRL response to PrRP, and GH release was only increased in the presence of estradiol. Although PRL secretion from PRL-cell adenomas was not affected by PrRP, PrRP induced PRL release from cultures of a GH-cell adenoma that cosecreted PRL. PrRP enhanced GH release in several GH-secreting adenomas studied by 25–27%, including GH stimulation in a mixed PRL-GH-cell tumor. These results show for the first time direct in vitro effects of PrRP-31 on human pituitary cells. PrRP is less potent than TRH in releasing PRL from human fetal lactotrophs and is unable to release PRL from PRL-cell adenomas in culture, but stimulated GH from several somatotroph adenomas. Thus, PrRP may participate in regulating GH, in addition to PRL, in the human pituitary.

scholarly journals HGG-04. ZINC ENHANCES TEMOZOLOMIDE CYTOTOXICITY IN PEDIATRIC GLIOBLASTOMA MULTIFORME MODEL SYSTEM

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii344-iii345
Author(s):  
Amos Toren ◽  
Michal Yalon ◽  
Aner Dafni ◽  
Ruty Mehrian-Shai
Keyword(s):  
Glioblastoma Multiforme ◽  
Combined Treatment ◽  
Model System ◽  
Growth Fraction ◽  
Mutant P53 ◽  
Viability Analysis ◽  
Number Of Patients ◽  
Pediatric Glioblastoma

Abstract BACKGROUND Temozolomide (TMZ) is an alkylating agent that has become the mainstay treatment of the most malignant brain cancer, glioblastoma multiforme (GBM). Unfortunately only a limited number of patients respond to it positively. We have shown that zinc metal reestablishes chemosensitivity in adult GBM in vitro and also in vivo but this effect has not been tested with pediatric GBM. METHODS Using Human pediatric glioblastoma cell lines- KNS42 (mutant p53/ MGMT [+]) and SF188 (mutant p53/ MGMT [-]), we investigated whether addition of zinc to TMZ enhances its cytotoxicity against GBM. RESULTS In vitro cell viability analysis showed that the cytotoxic activity of TMZ was substantially increased with addition of zinc and this response was accompanied by an elevation of p21, PUMA, BAX and a decrease in growth fraction as manifested by low ki67. Beta gal analysis showed that most of the remaining cells after the combination therapy are in senescence state. In order to eliminate the senescent population created as a result of the combined treatment of TMZ and Zinc, we decided to use a senolytic agent Navitoclax (ABT-263) that was demonstrated to be effective in reducing senescent cells by specific inhibition of Bcl-2, Bcl-XL and Bcl-w. Following the addition of Navitoclax to the combined treatment, SF188 cells, but not KNS42, show a significance reduction in viability compare to the combination treatment. CONCLUSIONS Our results suggest that zinc may serve as a potentiator of TMZ therapy in pediatric GBM patients and using a second hit with senolytic drug in some cases may be even more beneficial.

scholarly journals Nonlytic Exocytosis of Cryptococcus neoformans from Macrophages Occurs In Vivo and Is Influenced by Phagosomal pH

mBio ◽  
2011 ◽  
Vol 2 (4) ◽  
Author(s):  
André Moraes Nicola ◽  
Emma J. Robertson ◽  
Patrícia Albuquerque ◽  
Lorena da Silveira Derengowski ◽  
Arturo Casadevall
Keyword(s):  
Cryptococcus Neoformans ◽  
Ammonium Chloride ◽  
Vacuolar Atpase ◽  
Bafilomycin A1 ◽  
Atpase Inhibitor ◽  
Major Question ◽  
Content Type ◽  
Weak Bases

ABSTRACTA unique aspect of the interaction of the fungusCryptococcus neoformanswith macrophages is the phenomenon of nonlytic exocytosis, also referred to as “vomocytosis” or phagosome extrusion/expulsion, which involves the escape of fungal cells from the phagocyte with the survival of both cell types. This phenomenon has been observed onlyin vitrousing subjective and time-consuming microscopic techniques. In spite of recent advances in our knowledge about its mechanisms, a major question still remaining is whether this phenomenon also occursin vivo. In this study, we describe a novel flow cytometric method that resulted in a substantial gain in throughput for studying phagocytosis and nonlytic exocytosisin vitroand used it to explore the occurrence of this phenomenon in a mouse model of infection. Furthermore, we tested the hypothesis that host cell phagosomal pH affected nonlytic exocytosis. The addition of the weak bases ammonium chloride and chloroquine resulted in a significant increase of nonlytic exocytosis events, whereas the vacuolar ATPase inhibitor bafilomycin A1 had the opposite effect. Although all three agents are known to neutralize phagosomal acidity, their disparate effects suggest that phagosomal pH is an important and complex variable in this process. Our experiments established that nonlytic exocytosis occurredin vivowith a frequency that is possibly much higher than that observedin vitro. These results in turn suggest that nonlytic exocytosis has a potential role in the pathogenesis of cryptococcosis.IMPORTANCECryptococcus neoformanscauses disease in people with immune deficiencies such as AIDS. Upon infection,C. neoformanscells are ingested by macrophage immune cells, which provide a niche for survival and replication. After ingestion, macrophages can expel the fungi without causing harm to either cell type, a process named nonlytic exocytosis. To dissect this phenomenon, we evaluated its dependence on the pH inside the macrophage and addressed its occurrence during infection of mice. We developed new techniques using flow cytometry to measureC. neoformansinternalization by and nonlytic exocytosis from macrophages. Neutralizing the phagosome acidity changed the rate of nonlytic exocytosis: activity increased with the weak bases chloroquine and ammonium chloride, whereas the vacuolar ATPase inhibitor bafilomycin A1 caused it to decrease. Experiments in mice suggested that nonlytic exocytosis occurred during infection withC. neoformans. These results shed new light on the interaction betweenC. neoformansand host macrophages.

Differential in vitro effects of chemotherapeutic agents on primary cultures of human ovarian carcinoma

2004 ◽  
Vol 14 (4) ◽  
pp. 607-615 ◽  
Author(s):  
P. Kornblith ◽  
R. L. Ochs ◽  
A. Wells ◽  
M. J. Gabrin ◽  
J. Piwowar ◽  
...  
Keyword(s):  
Ovarian Carcinoma ◽  
Primary Cultures ◽  
Chemotherapeutic Agents ◽  
Human Ovarian Carcinoma ◽  
In Vitro Effects
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