Medroxyprogesterone effects on colony growth, autophagy and mitochondria of C6 glioma cells are augmented with tibolone and temozolomide

Progesterone boosts abiraterone-driven target and NK cell therapies against glioblastoma

INTRODUCTION

Glioblastoma (GBM) poses a significant challenge in oncology, with median survival times barely extending beyond a year due to resistance to standard therapies like temozolomide (TMZ). This study introduces a novel therapeutic strategy combining progesterone (Prog) and abiraterone (Abi) aimed at enhancing GBM treatment efficacy by modulating the tumor microenvironment and augmenting NK cell-mediated immunity.

METHODS

We employed in vitro and in vivo GBM models to assess the effects of Prog and Abi on cell viability, proliferation, apoptosis, and the immune microenvironment. Techniques included cell viability assays, Glo-caspase 3/7 apoptosis assays, RNA-seq and qPCR for gene expression, Seahorse analysis for mitochondrial function, HPLC-MS for metabolomics analysis, and immune analysis by flow cytometry to quantify NK cell infiltration.

RESULTS

Prog significantly reduced the IC50 of Abi in TMZ-resistant GBM cell, suggesting the enhanced cytotoxicity. Treatment induced greater apoptosis than either agent alone, suppressed tumor growth, and prolonged survival in mouse models. Notably, there was an increase in CD3-/CD19-/CD56+/NK1.1+ NK cell infiltration in treated tumors, indicating a shift towards an anti-tumor immune microenvironment. The combination therapy also resulted in a reduction of MGMT expression and a suppression of mitochondrial respiration and glycolysis in GBM cells.

CONCLUSION

The combination of Prog and Abi represents a promising therapeutic approach for GBM, showing potential in suppressing tumor growth, extending survival, and modulating the immune microenvironment. These findings warrant further exploration into the clinical applicability of this strategy to improve outcomes for GBM patients.

Ulipristal-temozolomide-hydroxyurea combination for glioblastoma: in-vitro studies

BACKGROUND

Glioblastoma multiforme (GBM) is a brain malignancy with worst survival. Low dose progesterone stimulates GBM growth, while progesterone receptor (PR)-antagonist mifepristone was shown to reduce growth and to enhance temozolomide sensitivity in GBM cells. Mifepristone is not available in all countries due to ethical reasons and may cause adrenal insufficiency and pelvic infections. Ulipristal is also a PR-antagonist used in treatment of uterine leiomyomas with higher biosafety. Ulipristal is demonstrated to suppress growth of breast cancer, yet it is not tested as yet whether it can also block growth and sensitize to temozolomide in glioblastoma as it was previously shown with mifepristone. Our first aim was to detect whether ulipristal exerts antiproliferative and chemotherapy-sensitizing effects in glioblastoma. Hydroxyurea inhibits DNA replication via blocking ribonucleotide reductase (RR) and it was demonstrated to increase temozolomide antineoplasticity in GBM. Progesterone receptor-activation in the uterus enhances RR transcription. Hence, we have hypothesized that PR-inactivation with ulipristal would further enhance hydroxyurea antineoplasticity by shutting down DNA synthesis mechanisms through further suppression of RR. Lastly, there exists no study as yet whether ulipristal, hydroxyurea and temozolomide could exert ternary antineoplastic efficacy, which was our last aim to define.

METHODS

To reveal interactions between ulipristal, hydroxyurea and temozolomide, we treated human U251 GBM cell line with these agents alone and in combination and measured cell proliferation, total antioxidant capacity (TAC) and total oxidant status (TOS) in conditioned medium and cellular cytokine gene expressions.

RESULTS

All agents significantly reduced cell proliferation significantly, yet the most significant decrease of GBM cells occurred with the triple drug combination at the 96th hour. All agents significantly decreased TAC and increased TOS in culture media, which was mostly relevant for the triple combination at the 96th hour. All these three agents tend to reduce the expression of immunosuppressive and/or GBM-growth stimulating cytokines TGF-β, IL-10 and IL-17 while increasing the expression of GBM-growth suppressing cytokine IL-23.

CONCLUSIONS

Reproposal of these agents in treatment of GBM would be a plausible approach if future studies prove their efficacy.

Deep multilayer brain omics identifies the potential involvement of menopause molecular networks in Gliomas' disease progression

The risk of high-grade gliomas is lower in young females, however, its incidence enhances after menopause, suggesting potential protective roles of female sex hormones. Hormone oscillations after menopause have received attention as a possible risk factor. Little is known about risk factors for adult gliomas. We examined the association of the aging brain after menopause, determining the risk of gliomas with proteomics and the MALDI-MSI experiment. Menopause caused low neurotransmitter levels such as GABA and ACH, high inflammatory factor levels like il-1β, and increased lipid metabolism-related levels like triglycerides in the brain. Upregulated and downregulated proteins after menopause were correlated with differentially expressed glioma genes, such as ACTA2, CAMK2D, FNBPIL, ARL1, HEBP1, CAST, CLIC1, LPCAT4, MAST3, and DOCK9. Furthermore, differential gene expression analysis of monocytes showed that the downregulated gene LPCAT4 could be used as a marker to prevent menopausal gliomas in women. Our findings regarding the association of menopause with the risk of gliomas are consistent with several extensive cohort studies. In view of the available evidence, postmenopausal status is likely to represent a significant risk factor for gliomas.

Crosstalk Between ROS and Autophagy in Tumorigenesis: Understanding the Multifaceted Paradox

Cancer formation is a highly regulated and complex process, largely dependent on its microenvironment. This complexity highlights the need for developing novel target-based therapies depending on cancer phenotype and genotype. Autophagy, a catabolic process, removes damaged and defective cellular materials through lysosomes. It is activated in response to stress conditions such as nutrient deprivation, hypoxia, and oxidative stress. Oxidative stress is induced by excess reactive oxygen species (ROS) that are multifaceted molecules that drive several pathophysiological conditions, including cancer. Moreover, autophagy also plays a dual role, initially inhibiting tumor formation but promoting tumor progression during advanced stages. Mounting evidence has suggested an intricate crosstalk between autophagy and ROS where they can either suppress cancer formation or promote disease etiology. This review highlights the regulatory roles of autophagy and ROS from tumor induction to metastasis. We also discuss the therapeutic strategies that have been devised so far to combat cancer. Based on the review, we finally present some gap areas that could be targeted and may provide a basis for cancer suppression.

The Sex Bias of Cancer

In hormone-dependent organs, sex hormones and dysregulated hormone signaling have well-documented roles in cancers of the breast and female reproductive organs including endometrium and ovary, as well as in prostate and testicular cancers in males. Strikingly, epidemiological data highlight significant differences between the sexes in the incidence of various cancers in nonreproductive organs, where the role of sex hormones has been less well studied. In an era when personalized medicine is gaining recognition, understanding the molecular, cellular, and biological differences between men and women is timely for developing more appropriate therapeutic interventions according to gender. We review evidence that sex hormones also shape many of the dysregulated cellular and molecular pathways that lead to cell proliferation and cancer in nonreproductive organs.

Caprylic (Octanoic) Acid as a Potential Fatty Acid Chemotherapeutic for Glioblastoma

High grade glial tumors (HGGs) including anaplastic astrocytoma (WHO Grade-III) and glioblastoma multiforme (GBM, WHO Grade-IV) are among the most malignant cancers known to man. Due to their defective mitochondria, HGG cells consume glucose via glycolysis even in the presence of oxygen. Overall survival is worse in HGG patients that are hyperglycemic. Unlike normal neural cells, HGG cells cannot efficiently metabolize ketone bodies for energy. Thus, a metabolic treatment based on therapeutic ketosis (reduced glucose with elevated ketone bodies) was proposed to treat GBM and was supoported from preclinical studies. Caprylic (octanoic) acid, a monocarboxylated saturated fatty acid, is among the best producers of ketone bodies and induces necrosis of experimental tumors at high dose. Caprylic acid is enriched in coconut and in goat's milk. It is also a posttranslational modifier of the ghrelin hormone and is produced in trace amounts in human tissues. Caprylic acid is a straight-chain isomer of the antiepileptic valproic acid, which is used in treatment of HGG-associated seizures and which may increase survival in GBM patients according to epidemiological observations. Among the valproic acids analogs tested, caprylic acid is the most potent molecule to block C6 astrocytoma cell growth in vitro and accumulates selectively within glial cells as shown by Positron Emission Tomography in vivo. Caprylic acid blocks glycolysis both in healthy liver and in malignant liver cells, which is more prominent in the latter and also lowers blood glucose. Noteworthy, caprylic acid exerts neuroprotective- and mitochondria-protective effects in several models of neurodegenerative diseases. Boost injections of caprylic acid at non-toxic levels during classical ketogenic metabolic therapy may fortify antitumor actions and reduce systemic toxicity by differential programming of mitochondrial and other metabolic pathways.

Autophagy as a Potential Therapy for Malignant Glioma

Glioma is the most frequent and aggressive type of brain neoplasm, being anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM), its most malignant forms. The survival rate in patients with these neoplasms is 15 months after diagnosis, despite a diversity of treatments, including surgery, radiation, chemotherapy, and immunotherapy. The resistance of GBM to various therapies is due to a highly mutated genome; these genetic changes induce a de-regulation of several signaling pathways and result in higher cell proliferation rates, angiogenesis, invasion, and a marked resistance to apoptosis; this latter trait is a hallmark of highly invasive tumor cells, such as glioma cells. Due to a defective apoptosis in gliomas, induced autophagic death can be an alternative to remove tumor cells. Paradoxically, however, autophagy in cancer can promote either a cell death or survival. Modulating the autophagic pathway as a death mechanism for cancer cells has prompted the use of both inhibitors and autophagy inducers. The autophagic process, either as a cancer suppressing or inducing mechanism in high-grade gliomas is discussed in this review, along with therapeutic approaches to inhibit or induce autophagy in pre-clinical and clinical studies, aiming to increase the efficiency of conventional treatments to remove glioma neoplastic cells.