Study of effectiveness of mifepristone for glioma cell line growth suppression

Progesterone at high doses reduces the growth of U87 and A172 glioblastoma cells: Proteomic changes regarding metabolism and immunity

While pregnancy may accelerate glioblastoma multiforme (GBM) growth, parity and progesterone (P4) containing treatments (ie, hormone replacement therapy) reduce the risk of GBM development. In parallel, low and high doses of P4 exert stimulating and inhibitory actions on GBM growth, respectively. The mechanisms behind the high‐dose P4‐suppression of GBM growth is unknown. In the present study, we assessed the changes in growth and proteomic profiles when high‐dose P4 (100 and 300 µM) was administered in human U87 and A172 GBM cell lines. The xCELLigence system was used to examine cell growth when different concentrations of P4 (20, 50, 100, and 300 µM) was administered. The protein profiles were determined by two‐dimensional gel electrophoresis in both cell lines when 100 and 300 µM P4 were administered. Finally, the pathways enriched by the differentially expressed proteins were assessed using bioinformatic tools. Increasing doses of P4 blocked the growth of both GBM cells. We identified 26 and 51 differentially expressed proteins (fc > 2) in A172 and U87 cell lines treated with P4, respectively. Only the pro‐tumorigenic mitochondrial ornithine aminotransferase and anti‐apoptotic mitochondrial 60 kDa heat shock protein were downregulated in A172 cell line and U87 cell line when treated with P4, respectively. Detoxification of reactive oxygen species, cellular response to stress, glucose metabolism, and immunity‐related proteins were altered in P4‐treated GBM cell lines. The paradox on the effect of low and high doses of P4 on GBM growth is gaining attention. The mechanism related to the high dose of P4 on GBM growth can be explained by the alterations in detoxification mechanisms, stress, and immune response and glucose metabolism. P4 suppresses GBM growth and as it is nontoxic in comparison to classical chemotherapeutics, it can be used as a new strategy in GBM treatment in the future.

Effects of progesterone on the cell number of gliomaspheres derived from human glioblastoma cell lines

AIMS

The malignancy of the Glioblastomas (GBM), the most frequent and aggressive brain tumors, have been associated with the presence of glioma stem cells (GSCs) which can form gliomaspheres (GS) in vitro. Progesterone (P) increases the proliferation, migration, and invasion of GBM cell lines through the interaction with its intracellular receptor (PR). However, it is unknown if the PR is expressed and the possible effects of P in the formation/differentiation of GS.

MAIN METHODS

GS were grown from U251 and U87 cell lines by selective culture with serum-free neural stem cell medium. GSCs were identified by the detection of Sox2, Ki67, Nestin, CD133, and CD15 by immunofluorescence. Additionally, the relative expression of PROM1, NES, SOX2, OLIG2, EZH2, BMI1 and PR genes was evaluated by RT-qPCR. The GS were treated with P, and the number of cells was quantified. By RT-PCR the βIII-TUB and GFAP differentiation genes were evaluated.

KEY FINDINGS

GS were maintained until passage four. The expression of all GSCs markers was significantly higher in GS as compared with the basal culture of U251 and U87 cells. We demonstrated for the first time that PR is expressed in GS and this expression was higher as compared with the U251 and U87 cells in basal conditions. Also, we observed that P increased the number of cells derived primary gliomaspheres (GS1) from the U251 line, as well as the expression of the neuronal differentiation marker βIII-TUB.

SIGNIFICANCE

These results suggest the participation of P in the growth of GSCs.

Expression of Progesterone Receptor Membrane Component 1 (PGRMC1), Progestin and AdipoQ Receptor 7 (PAQPR7), and Plasminogen Activator Inhibitor 1 RNA-Binding Protein (PAIRBP1) in Glioma Spheroids In Vitro

Objective. Some effects of progesterone on glioma cells can be explained through the slow, genomic mediated response via nuclear receptors; the other effects suggest potential role of a fast, nongenomic action mediated by membrane-associated progesterone receptors. Methods. The effects of progesterone treatment on the expression levels of progesterone receptor membrane component 1 (PGRMC1), plasminogen activator inhibitor 1 RNA-binding protein (PAIRBP1), and progestin and adipoQ receptor 7 (PAQR7) on both mRNA and protein levels were investigated in spheroids derived from human glioma cell lines U-87 MG and LN-229. Results. The only significant alteration at the transcript level was the decrease in PGRMC1 mRNA observed in LN-229 spheroids treated with 30 ng/mL of progesterone. No visible alterations at the protein levels were observed using immunohistochemical analysis. Stimulation of U-87 MG spheroids resulted in an increase of PGRMC1 but a decrease of PAIRBP1 protein. Double immunofluorescent detection of PGRMC1 and PAIRBP1 identified the two proteins to be partially colocalized in the cells. Western blot analysis revealed the expected bands for PGRMC1 and PAIRBP1, whereas two bands were detected for PAQR7. Conclusion. The progesterone action is supposed to be mediated via membrane-associated progesterone receptors as the nuclear progesterone receptor was absent in tested spheroids.

Anti-tumor effects of progesterone in human glioblastoma multiforme: role of PI3K/Akt/mTOR signaling

Glioblastoma multiforme (GBM) is an aggressive primary brain tumor with a mean patient survival of 13-15 months despite surgical resection, radiation therapy and standard-of-care chemotherapy. We investigated the chemotherapeutic effects of the hormone progesterone (P4) on the growth of human GBM in four genetically different cell lines (U87MG, U87dEGFR, U118MG, LN-229) in vitro and in a U87MG subcutaneous xenograft mouse model. At high concentrations (20, 40, and 80 μM), P4 significantly (P<0.05) decreased tumor cell viability in all cell lines except LN-229. This effect was not blocked by the P4 receptor antagonist RU468. Conversely, at low physiological concentrations (0.1, 1, and 5 μM) P4 showed a proliferative effect in all cell lines which was blocked by RU486. In nude mice, P4 (100 and 200 mg/kg) inhibited tumor growth significantly (P<0.05) over 5 weeks of treatment and extended survival time of tumor-bearing mice by 60% without signs of systemic toxicity. P4 suppressed tumor vascularization as indicated by the expression of CD31, vascular endothelial growth factor and matrix metalloproteinase-9. Apoptosis in tumor tissue was detected by the expression of cleaved caspase-3, BCl-2, BAD and p53 proteins and confirmed by TUNEL assay. P4 treatment also suppressed PI3K/Akt/mTOR signaling, which regulates tumor growth, as demonstrated by the suppression of proliferating cell nuclear antigen. Our data can be interpreted to suggest that P4 suppresses the growth of human GBM cells both in vitro and in vivo and enhances survival time in mice without any demonstrable side effects. This article is part of a Special Issue entitled 'Sex steroids and brain disorders'.

Growth hormone exposure as a risk factor for the development of subsequent neoplasms of the central nervous system: a report from the childhood cancer survivor study

CONTEXT

Cranial radiation therapy (CRT) predisposes to GH deficiency and subsequent neoplasms (SNs) of the central nervous system (CNS). Increased rates of SNs have been reported in GH-treated survivors.

OBJECTIVE

The objective of the study was to evaluate the association between GH treatment and the development of CNS-SNs.

DESIGN

The study was designed with a retrospective cohort with longitudinal follow-up.

SETTING

The setting of the study was multiinstitutional.

PARTICIPANTS

A total of 12 098 5-year pediatric cancer survivors from the Childhood Cancer Survivor Study, diagnosed with cancer prior to age 21 years, of whom 338 self-reported GH treatment, which was verified through medical record review.

INTERVENTIONS

INTERVENTIONS included subject surveys, medical records abstraction, and pathological review.

OUTCOME MEASURES

Incidence of meningioma, glioma, and other CNS-SNs was measured.

RESULTS

Among GH-treated survivors, 16 (4.7%) developed CNS-SN, including 10 with meningioma and six with glioma. Two hundred three survivors without GH treatment (1.7%) developed CNS-SN, including 138 with meningioma, 49 with glioma, and 16 with other CNS-SNs. The adjusted rate ratio in GH-treated compared with untreated survivors for development of any CNS-SN was 1.0 [95% confidence interval (CI) 0.6-1.8, P = .94], for meningiomas, 0.8 (95% CI 0.4-1.7, P = .61), and for gliomas, 1.9 (95% CI 0.7-4.8, P = .21). Factors associated with meningioma development included female gender (P = .001), younger age at primary cancer diagnosis (P < .001), and CRT/longer time since CRT (P < .001). Glioma was associated with CRT/shorter time since CRT (P < .001).

CONCLUSIONS

There was no statistically significant increased overall risk of the occurrence of a CNS-SN associated with GH exposure. Specifically, occurrence of meningiomas and gliomas were not associated with GH treatment.

Progesterone induces the growth and infiltration of human astrocytoma cells implanted in the cerebral cortex of the rat

Progesterone (P4) promotes cell proliferation in several types of cancer, including brain tumors such as astrocytomas, the most common and aggressive primary intracerebral neoplasm in humans. In this work, we studied the effects of P4 and its intracellular receptor antagonist, RU486, on growth and infiltration of U373 cells derived from a human astrocytoma grade III, implanted in the motor cortex of adult male rats, using two treatment schemes. In the first one, fifteen days after cells implantation, rats were daily subcutaneously treated with vehicle (propylene glycol, 160  μ L), P4 (1 mg), RU486 (5 mg), or P4 + RU486 (1 mg and 5 mg, resp.) for 21 days. In the second one, treatments started 8 weeks after cells implantation and lasted for 14 days. In both schemes we found that P4 significantly increased the tumor area as compared with the rest of the treatments, whereas RU486 blocked P4 effects. All rats treated with P4 showed tumor infiltration, while 28.6% and 42.9% of the animals treated with RU486 and P4 + RU486, respectively, presented it. Our data suggest that P4 promotes growth and migration of human astrocytoma cells implanted in the motor cortex of the rat through the interaction with its intracellular receptor.