cholecalciferol and Glioblastoma

Glioma is the most prevalent primary brain tumor in adults among which glioblastoma is the most malignant and lethal subtype. Its common resistance to conventional chemotherapeutics calls for the development of alternative or concomitant treatment. Taking advantage of its endocrine function as a neurosteroid, vitamin D has become a target of interest to be used in conjunction with different chemotherapies. In this article, we review the mechanisms through which vitamin D and its analogs induce anti-tumor activity in glioblastoma, and the practical issues relevant to their potential application based on in vitro and in vivo studies. Vitamin D has largely been reported to promote cell cycle arrest and induce cell death to suppress tumor growth in glioblastoma. Glioblastoma cells treated with vitamin D have also shown reduced migratory and invasive phenotypes, and reduced stemness. It is worth noting that vitamin D analogs are able to produce similar inhibitory actions without causing adverse effects such as hypercalcemia in vivo. Upregulation of vitamin D receptors by vitamin D and its analogs may also play a role in enhancing its anti-tumor activity. Based on current findings and taking into consideration its potential cancer-protective effects, the clinical application of vitamin D in glioblastoma treatment and prevention will be discussed. With some study findings subject to controversy, further investigation is warranted to elucidate the mechanism of action of vitamin D and to evaluate relevant issues regarding its treatment efficacy and potential clinical application.

Topics: Animals; Apoptosis; Brain Neoplasms; Calcitriol; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cholecalciferol; Glioblastoma; Humans; Receptors, Calcitriol; Vitamin D; Vitamins

Glioblastoma is one of the most common malignant brain tumors. Vitamin D, primarily its hormonally active form calcitriol, has been reported to have anti-cancer activity. In the present study, we used patient-derived glioma cell lines to examine the effect of vitamin D3 and calcitriol on glioblastoma. Surprisingly, vitamin D3 showed a more significant inhibitory effect than calcitriol on cell viability and proliferation. Vitamin D receptor (VDR) mediates most of the cellular effects of vitamin D, and thus we examined the expression level and function of VDR via gene silencing and gene knockout experiments. We observed that VDR does not affect the sensitivity of patient-derived glioma cell lines to vitamin D3, and the gene encoding VDR is not essential for growth of patient-derived glioma cell lines. RNA sequencing data analysis and sterolomics analysis revealed that vitamin D3 inhibits cholesterol synthesis and cholesterol homeostasis by inhibiting the expression level of 7-dehydrocholesterol reductase, which leads to the accumulation of 7-dehydrocholesterol and other sterol intermediates. In conclusion, our results suggest that vitamin D3, rather than calcitriol, inhibits growth of patient-derived glioma cell lines via inhibition of the cholesterol homeostasis pathway.

Topics: Calcitriol; Cell Line; Cholecalciferol; Cholesterol; Glioblastoma; Homeostasis; Humans; Vitamin D

A better understanding of the vitamin D(3) metabolism is required to evaluate its potential therapeutic value for cancers. Here, we set out to contribute to the understanding of vitamin D(3) metabolism in glioblastoma multiforme.. We did nested touchdown reverse transcription-PCR (RT-PCR) to identify CYP27B1 splice variants and real-time RT-PCR to quantify the expression of CYP27B1. A cell line was treated with calcitriol to determine the effect on the expression of CYP27B1, 1alpha,25-dihydroxyvitamin D(3)-24-hydroxylase (CYP24), and vitamin D(3) receptor (VDR). We generated three antibodies for the specific detection of CYP27B1 and splice variants. High-performance TLC was done to determine the endogenous CYP27B1 activity and the functionality of CYP27B1 splice variants. Using WST-1 assay, we determined the effect of vitamin D(3) metabolites on proliferation.. We report a total of 16 splice variants of CYP27B1 in glioblastoma multiforme and a different expression of CYP27B1 and variants between glioblastoma multiforme and normal tissues. We found preliminary evidence for enzymatic activity of endogenous CYP27B1 in glioblastoma multiforme cell cultures but not for the functionality of the splice variants. By adding calcitriol, we found a proliferative effect for some cell lines depending on the dose of calcitriol. The administration of calcitriol led to an elevated expression of CYP27B1 and CYP24 but left the expression of the VDR unaltered.. Our findings show that glioblastoma multiforme cell lines metabolize calcidiol. In addition, we show various effects mediated by calcitriol. We found a special vitamin D(3) metabolism and mode of action in glioblastoma multiforme that has to be taken into account in future vitamin D(3)-related therapies.

Topics: 25-Hydroxyvitamin D3 1-alpha-Hydroxylase; Alternative Splicing; Animals; Blotting, Western; Brain Neoplasms; Calcifediol; Calcitriol; Calcium Channel Agonists; Cell Line, Tumor; Cell Proliferation; Cholecalciferol; Chromatography, Thin Layer; Cloning, Molecular; COS Cells; DNA, Complementary; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Plasmids; Rats; Receptors, Calcitriol; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Messenger; Steroid Hydroxylases; Transfection; Vitamin D3 24-Hydroxylase

The aim was to determine the ability of macrophage-activated killer cells (MAK cells) obtained from peripheral blood of normal volunteers to kill glioblastoma multiforme (GBM) cell lines. Another goal was to investigate whether a bispecific antibody (bsAb) MDX-447, recognizing the high-affinity Fc receptor for IgG (FcgammaRI) and epidermal growth factor receptor (EGFR), would enhance MAK cell tumoricidal activity.. Monocytes, from leukapheresis product, were isolated by countercurrent elutriation and differentiated into MAK cells by culture with granulocyte/macrophage-colony-stimulating factor, vitamin D3 and interferon gamma. Cells were checked for sterility, endotoxin and phenotypic markers. MAK cell functional activity was measured by a flow-cytometric phagocytosis assay. Target cells, a carcinoma cell line and two glioma cell lines expressing EGFR, were stained with PKH-26. MAK cells were labeled with fluorescein-conjugated anti-CD14. Combined effectors, targets and bsAb were incubated and the percentage of MAK cells with phagocytosed targets was determined by flow cytometry.. We demonstrate that a large number of highly purified monocytes, isolated from peripheral blood, can be differentiated into MAK cells for use as an adjuvant for cancer treatment. After culture these cells are sterile, endotoxin-free and comprise more than 95% MAK cells. Increased amounts of CD14, CD64 and HLA-DR, which are characteristics of macrophage activation, were expressed. MAK cells were extremely phagocytic in comparison to monocytes, even in the absence of bsAb. Moreover, bsAb enhanced the tumoricidal activity of elutriated MAK cells targeted against GBM cell lines. Therefore, intracavity MAK cells armed with MDX-447 could be an effective adoptive immunotherapy for EGFR-positive GBM.

Topics: Adjuvants, Immunologic; Antibodies; Antibodies, Monoclonal; Cell Differentiation; Cells, Cultured; Cholecalciferol; Dose-Response Relationship, Drug; ErbB Receptors; Flow Cytometry; Glioblastoma; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Immunotherapy; Interferon-gamma; Killer Cells, Natural; Lipopolysaccharide Receptors; Lung Neoplasms; Macrophages; Microscopy, Confocal; Monocytes; Phagocytosis; Phenotype; Receptor, ErbB-2; Receptors, IgG; Tumor Cells, Cultured

1 alpha, 25-dihydroxyvitamin D3 was previously shown to induce cell death in brain tumour cell lines when added to the medium at micromolar concentration. In this paper we show that Cholecalciferol, a poor ligand of the vitamin D receptor, also induces cell death of HU197 human glioblastoma cell line and early passages cultures derived from a recurrent human glioblastoma. This finding suggests that the effects of vitamin D metabolites on brain tumour cells are at least partially independent from the activation of the classic nuclear receptor pathway. Vitamin D metabolites have been shown to activate the sphingomyelin pathway inducing an increase in cellular ceramide concentration. We determined the levels of sphingomyelin ceramide and ganglioside GD3 in Hu197 cells after treatment with cholecalciferol. A significant increase in ceramide concentration and a proportional decrease in sphingomyelin was already present after 6 hours of cholecalciferol treatment when no morphological changes were visible in the cultures. Treatment with ceramides (N-acetylsphingosine or natural ceramide from bovine brain) of the same cells also induces cell death. Similarly, treatment of the same cells with bacterial Sphingomyelinase also results in cell death. The demonstration of an increase in intracellular ceramide after cholecalciferol treatment and the ability of ceramide to induce cell death suggest that the sphingomyelin pathway may be implicated in the effect of vitamin D metabolites on human glioblastoma cells. Inhibition of ceramide biosynthesis by fumonisin B1 treatment did not alter the dose response curve of HU197 cells to cholecalciferol. Insensitivity to fumonisin B1 together with a decrease in sphingomyelin content after cholecalciferol treatment indicate that activation of sphingomyelinase should be responsible for the increase in intracellular ceramide concentration.

Topics: Animals; Brain Neoplasms; Cattle; Cell Death; Ceramides; Cholecalciferol; Enzyme Activation; Glioblastoma; Humans; Signal Transduction; Sphingomyelin Phosphodiesterase; Sphingomyelins; Tumor Cells, Cultured; Vitamin D

The biological significance of vitamin D receptors expressed by glioblastoma and other glial tumours is still unclear. In an effort to clarify this issue we studied the effects of increasing concentrations of 25-dihydroxyvitamin D3 and its metabolite 1 alpha,25-dihydroxyvitamin D3 on two human glioblastoma cell lines. Both substances were capable of inducing a significant (> 50%) reduction in growth of the two glioblastoma cell lines at dosages over 5 microM. When the HU 70 cell line was treated by increasing dilutions of 25-dihydroxyvitamin D3 combined with 1 microM all trans-retinoic acid, significant inhibition was apparent even after addition of 25-dihydroxyvitamin D3 in the nanomolar range. Reduction of growth index was mainly due to induced cell death. Our results provide in vitro evidence that vitamin D metabolites alone or in combination with retinoids may be potentially useful agents in the differentiation therapy of human malignant gliomas.

Topics: Brain Neoplasms; Calcitriol; Cell Line; Cholecalciferol; Dose-Response Relationship, Drug; Drug Synergism; Glioblastoma; Humans; Tretinoin; Tumor Cells, Cultured