Vitamin D receptor in SH-SY5Y human neuroblastoma cells and effect of 1,25-dihydroxyvitamin D3 on cellular proliferation

Vitamin D Status in Children With High-risk Neuroblastoma

BACKGROUND

Vitamin D deficiency has become a matter of concern in pediatric cancer patients. A relationship between neuroblastoma and Vitamin D signaling pathways has been revealed with interest in the antiproliferative and antiinvasive properties of vitamin D. Our aim is to describe the prevalence of Vitamin D deficiency among children with high-risk neuroblastoma (HR-NB) and to explore its association with disease status.

MATERIALS AND METHODS

In all, 182 patients with HR-NB were managed at our center from 2017 to 2021. Serum 25(OH)D levels were tested at the first blood analysis performed and correlated with clinical data and disease status.

RESULTS

One hundred forty-eight (81.4%) had low 25(OH)D levels (48.4% categorized as deficiency (25(OH)D below 20 ng/mL) and 33.0% as insufficiency (25(OH)D 20 to 30 ng/mL). Median Vitamin D level was 20.2 ng/mL. Vitamin D levels were not associated with race or sex. Although malnourished patients had lower median 25(OH)D levels(11.1 ng/mL), no statistical association was observed with Vitamin D deficiency. There was no association between Vitamin D levels and disease status. An inverse correlation was found between age and vitamin D levels ( P =0.0040).

CONCLUSION

A concerning high prevalence of low Vitamin D levels affects more than two-thirds of patients with HR-NB in our cohort, regardless of the disease status at the time of evaluation. Older children are at a higher risk for deficient levels of vitamin D.

Could VGF and/or its derived peptide act as biomarkers for the diagnosis of neurodegenerative diseases: A systematic review

BACKGROUND

The increasing ageing population has led to an increase in the prevalence of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). However, as yet, there are no simple biomarkers to predict the onset of such diseases. Recently, VGF and its peptides have been highlighted in neurodegenerative diseases. VGF (non-acronymic) is a polypeptide induced in PC12 cells by neurotrophic factors.

OBJECTIVE

This systematic review aimed to determine whether VGF and/or its derived peptides can be used as biomarkers for the diagnosis of ALS, PD, and AD with specific attention to (1) the levels of VGF and/or its derived peptides, (2) amyloid-beta, (3) dopamine, and (4) cognitive score.

METHODOLOGY

A search was undertaken in the Ovid EMBASE, Cochrane Library, PubMed, Scopus, and Web of Science for observational studies. Publications that assessed the level of VGF and/or its derived peptides among people with neurodegenerative diseases and compared them with healthy people were included. The quality of the included studies was assessed using the National Heart, Lung, and Blood Institute Quality Assessment Tool.

RESULT

A search of the databases yielded 834 studies, of which, eight observational studies met the inclusion criteria with a total of 673 participants (51.7% males) aged >18 years. Seven studies showed significant decreases in VGF and its derived peptides in adults with AD, PD, and ALS compared to healthy controls (p<0.05). However, one study showed that there was no significant difference in VGF in AD compared to healthy control(p>0.05). Furthermore, only one study reported that VGF levels were positively correlated with those of tissue dopamine but not with Aβ1-42, and low levels of VGF were associated to cognitive deficits.

CONCLUSION

The use of VGF and its derivatives for the diagnosis of PD, ALS, AD remains unclear, so further investigation of the role of VGF in neurodegenerative diseases and pathophysiology is needed to provide new insights.

1,25(OH)2D3 Alleviates Aβ(25-35)-Induced Tau Hyperphosphorylation, Excessive Reactive Oxygen Species, and Apoptosis Through Interplay with Glial Cell Line-Derived Neurotrophic Factor Signaling in SH-SY5Y Cells

Amyloid beta (Aβ) accumulation in the brain is one of the major pathological features of Alzheimer's disease. The active form of vitamin D (1,25(OH)₂D₃), which acts via its nuclear hormone receptor, vitamin D receptor (VDR), has been implicated in the treatment of Aβ pathology, and is thus considered as a neuroprotective agent. However, its underlying molecular mechanisms of action are not yet fully understood. Here, we aim to investigate whether the molecular mechanisms of 1,25(OH)₂D₃ in ameliorating Aβ toxicity involve an interplay of glial cell line-derived neurotrophic factor (GDNF)-signaling in SH-SY5Y cells. Cells were treated with Aβ(25-35) as the source of toxicity, followed by the addition of 1,25(OH)₂D₃ with or without the GDNF inhibitor, heparinase III. The results show that 1,25(OH)₂D₃ modulated Aβ-induced reactive oxygen species, apoptosis, and tau protein hyperphosphorylation in SH-SY5Y cells. Additionally, 1,25(OH)₂D₃ restored the decreasing GDNF and the inhibited phosphorylation of the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) protein expressions. In the presence of heparinase III, these damaging effects evoked by Aβ were not abolished by 1,25(OH)₂D_3. It appears 1,25(OH)₂D₃ is beneficial for the alleviation of Aβ neurotoxicity, and it might elicit its neuroprotection against Aβ neurotoxicity through an interplay with GDNF-signaling.

1α,25-Dihydroxyvitamin D3 up-regulates IL-34 expression in SH-SY5Y neural cells

Vitamin D supplementation is regarded as a novel approach to treat Alzheimer’s disease, but the underlying mechanism remains elusive. The cytokine IL-34 provides strong neuroprotective and survival signals in brain injury and neurodegeneration and could be an immunological mediator for the vitamin D-induced protection. The aim of this study was to investigate whether human IL-34 is up-regulated in neuronal cells by the hormonally active form of vitamin D, 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3]. We found that IL-34 was detectable in a variety of cell lines and its expression was strongly induced in SH-SY5Y neural cells in a dose- and time-dependent manner by 1α,25(OH)2D3 through the vitamin D receptor (VDR). Furthermore, we identified the core promoter of IL-34 gene and a VDR binding site (CGCCCT) that was required for 1α,25(OH)2D3-induced IL-34 expression. These findings suggest that the induction of IL-34 expression by 1α,25(OH)2D3 may constitute a mechanism that explains the protective function of vitamin D in Alzheimer’s disease.

Crosstalk between sphingolipids and vitamin D3: potential role in the nervous system

Sphingolipids are both structural and bioactive compounds. In particular, ceramide and sphingosine 1-phosphate regulate cell fate, inflammation and excitability. 1-α,25-dihydroxyvitamin D3 (1,25(OH)₂ D₃ ) is known to play an important physiological role in growth and differentiation in a variety of cell types, including neural cells, through genomic actions mediated by its specific receptor, and non-genomic effects that result in the activation of specific signalling pathways. 1,25(OH)₂ D₃ and sphingolipids, in particular sphingosine 1-phosphate, share many common effectors, including calcium regulation, growth factors and inflammatory cytokines, but it is still not known whether they can act synergistically. Alterations in the signalling and concentrations of sphingolipids and 1,25(OH)₂ D₃ have been found in neurodegenerative diseases and fingolimod, a structural analogue of sphingosine, has been approved for the treatment of multiple sclerosis. This review, after a brief description of the role of sphingolipids and 1,25(OH)₂ D₃ , will focus on the potential crosstalk between sphingolipids and 1,25(OH)₂ D₃ in neural cells.

Thyroid hormone and vitamin D regulate VGF expression and promoter activity

The Siberian hamster (Phodopus sungorus) survives winter by decreasing food intake and catabolizing abdominal fat reserves, resulting in a sustained, profound loss of body weight. Hypothalamic tanycytes are pivotal for this process. In these cells, short-winter photoperiods upregulate deiodinase 3, an enzyme that regulates thyroid hormone availability, and downregulate genes encoding components of retinoic acid (RA) uptake and signaling. The aim of the current studies was to identify mechanisms by which seasonal changes in thyroid hormone and RA signaling from tanycytes might ultimately regulate appetite and energy expenditure. proVGF is one of the most abundant peptides in the mammalian brain, and studies have suggested a role for VGF-derived peptides in the photoperiodic regulation of body weight in the Siberian hamster. In silico studies identified possible thyroid and vitamin D response elements in the VGF promoter. Using the human neuroblastoma SH-SY5Y cell line, we demonstrate that RA increases endogenous VGF expression (P<0.05) and VGF promoter activity (P<0.0001). Similarly, treatment with 1,25-dihydroxyvitamin D3 increased endogenous VGF mRNA expression (P<0.05) and VGF promoter activity (P<0.0001), whereas triiodothyronine (T3) decreased both (P<0.01 and P<0.0001). Finally, intra-hypothalamic administration of T3 blocked the short day-induced increase in VGF expression in the dorsomedial posterior arcuate nucleus of Siberian hamsters. Thus, we conclude that VGF expression is a likely target of photoperiod-induced changes in tanycyte-derived signals and is potentially a regulator of seasonal changes in appetite and energy expenditure.

Ganglioneuroblastoma-associated vitamin D deficiency rickets

Vitamin D deficiency is the most common cause of rickets mainly in breast-fed dark-skinned, African or Asian children receiving inadequate sunlight exposure. We report a case of a 1.5 year-old Afro-Italian male infant living in South Italy who came to our observation with the typical clinical picture of vitamin D deficiency rickets. The child was exclusively breast-fed for 8 months without vitamin D supplements. Owing to the rarity of vitamin D deficiency rickets in the South of Italy he underwent several investigations, which demonstrated the association with an abdominal ganglioneuroblastoma. To our knowledge, ganglioneuroblastoma has never been reported in association with vitamin D deficiency rickets. Although the association between these 2 rare conditions may be coincidental, the protective action of vitamin D against cancer suggests that vitamin D deficiency might have contributed to the development of ganglioneuroblastoma in our patient.

1 alpha-Hydroxyvitamin D2 inhibits growth of human neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in childhood. The poor outcomes of patients with high-risk neuroblastoma have encouraged the search for new therapies. In the current study, the effect of the vitamin D analog 1alpha-hydroxyvitamin D2 (1alpha-OH-D2, doxercalciferol) was assessed in a mouse xenograft model of human neuroblastoma. Vitamin D receptor (VDR) expression levels in seven neuroblastoma cell lines were compared using real-time PCR. SK-N-AS cells, which express relatively high levels of VDR, were injected into the flanks of 60 mice. The mice were treated daily via oral gavage for 5 weeks with vehicle (control), 0.15 microg, or 0.3 microg of 1alpha-OH-D2. The animals were then euthanized, and tumors, sera, and kidneys were collected and analyzed. End tumor volumes were significantly smaller in both the 0.15 microg group (712.07 mm3, P = 0.0121) and 0.3 microg group (772.97 mm3, P = 0.0209) when compared to controls (1,681.75 mm3). In terms of toxicity, serum calcium levels were increased but mortality was minimal in both treatment groups. These results were similar to those previously described in the transgenic (LHbeta-Tag) and human xenograft (Y-79) models of retinoblastoma, a related tumor. In vitro cell viability studies of SK-N-AS and NGP cells, which represent two major human neuroblastoma subtypes that differ in their genetic abnormalities as well as their VDR expression levels, show that both are sensitive to calcitriol, the active metabolite of vitamin D3. In conclusion, the present study shows that 1alpha-OH-D2 can inhibit human neuroblastoma growth in vivo with relatively low toxicity. The safety of 1alpha-OH-D2 has been extensively studied; the drug is FDA-approved for the treatment of adult kidney patients, and Phase I/II trials have been conducted in adult oncology patients. There should not be major obstacles to starting Phase I and II clinical trials with this drug in pediatric patients with high-risk neuroblastoma.

Calcitriol in cancer treatment: From the lab to the clinic

1,25-Dihydroxyvitamin D (calcitriol), the most active metabolite of vitamin D, has significant antineoplastic activity in preclinical models. Several mechanisms of activity have been proposed. These include inhibition of proliferation associated with cell cycle arrest and, in some models, differentiation, reduction in invasiveness and angiogenesis, and induction of apoptosis. Proposed mechanisms differ between tumor models and experimental conditions, and no unifying hypothesis about the mechanism of antineoplastic activity has emerged. Synergistic and/or additive effects with cytotoxic chemotherapy, radiation, and other cancer drugs have been reported. Significantly supraphysiological concentrations of calcitriol are required for antineoplastic effects. Such concentrations are not achievable in patients when calcitriol is dosed daily due to predictable hypercalcemia and hypercalcuria; however, phase I trials have demonstrated that intermittent dosing allows substantial dose escalation and has produced potentially therapeutic peak calcitriol concentrations. Recently, a phase II study reported encouraging levels of activity for the combination of high-dose calcitriol and docetaxel administered on a weekly schedule in patients with androgen-independent prostate cancer. This regimen is now under study in a placebo-controlled randomized trial in androgen-independent prostate cancer and in phase II studies in several other tumor types. Further work is needed to elucidate the molecular mechanisms of antineoplastic activity and optimal clinical applications of calcitriol in cancer.

Vitamin D receptor binding to DNA is altered without the change in its expression in human renal clear cell cancer

Vitamin D co-regulates cell proliferation, differentiation and apoptosis, the processes that are disturbed in cancer tissues. It acts through the vitamin D nuclear receptor (VDR) that binds to DNA in the regulatory sequences of the target genes. As the kidney is one of the key organs for vitamin D metabolism and action, we analyzed VDR expression and its DNA binding activity in human renal clear cell cancer. 24 tumors, 24 controls that were excised from the opposite pole of the same kidney and 7 controls originating from kidneys without cancer were examined. Independently of tumor grading neither Northern blots nor immunoblotting demonstrated statistically significant differences of the mean VDR mRNA and protein amounts, respectively, in the cancer as compared to both control types. In contrast, the amount of VDR-DNA complexes was lower in 52.2% of the tumors in comparison to their corresponding controls. After normalization against VDR receptor protein amount in 34.8% of the tumors VDR-DNA binding was at least 3-4 times weaker than in the controls. However, the expression of vitamin D-dependent P21 gene on the mRNA level was not decreased in these cancers. It remains to be elucidated if altered VDR function due to its impaired binding to DNA contributes to the process of tumorigenesis, and what potential vitamin D-dependent mechanisms are involved in this process.

Effects of vitamin D on the growth of normal and malignant B-cell progenitors

As the effects of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25-(OH)2-D3) (VD, calcitriol) on the proliferation and differentiation potential of normal and leukaemic cells in vitro of myeloid lineage are known, we investigated the response to VD on the growth of both normal and malignant lymphoid progenitors. Effects of vitamin D on normal human lymphoid progenitors and B lineage acute lymphoblastic leukaemia (ALL) progenitors were assessed by using an in vitro cell colony assay specific for either B or T cell lineages. The expression of VDR on B untreated malignant progenitors at diagnosis was investigated by RT-PCR analysis. VD induced a significant inhibition of normal lymphoid cell progenitors growth of both T and B lineage. VD inhibited significantly also the growth of malignant B cell lineage lymphoid progenitors, without inducing cytotoxic effect. As it has been reported that VD effects on activated lymphocytes are mediated by 1,25-(OH)2-D3 nuclear receptor (VDR), we investigated VDR expression on malignant B cell progenitors. We did not detect VDR expression on these cells examined at diagnosis. We demonstrated that VD inhibited in vitro the clonogenic growth of both normal and malignant lymphoid B cell progenitors and that this inhibitory effect on malignant B cell progenitors was not related to VDR. Our work contributes to understanding of the mechanism of action of this hormone in promoting cellular inhibition of clonal growth of malignant lymphoid B cell progenitors, suggesting that the regulation of some critical growth and differentiation factor receptors could be a key physiological role of this hormone.

Synergistic anti-proliferative effects of vitamin D derivatives and 9-cis retinoic acid in SH-SY5Y human neuroblastoma cells

This study examines the effect of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], two vitamin D analogues (KH 1060 and EB 1089, which are 20-epi-22-oxa and 22,24-diene-analogues, respectively), 9-cis retinoic acid and all-trans retinoic acid on proliferation of SH-SY5Y human neuroblastoma cells, after treatment for 7 days. Cell number did not change when the cells were incubated with 1, 10 or 100 nM 1,25(OH)(2)D(3) or its derivatives, but significantly decreased in the presence of the two retinoids (0.001--10 microM final concentration). A synergistic inhibition was observed, when SH-SY5Y cells were treated combining 0.1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060, and 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM EB 1089. Acetylcholinesterase activity showed a significant increase, in comparison with controls, after treatment of the cells for 7 days with 0.1 or 1 microM 9-cis retinoic acid, alone or combined with 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060 or 10 nM EB 1089. This increase was synergistic, combining 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or EB 1089. The levels of the c-myc encoded protein remarkably decreased after treatment of SH-SY5Y cells for 1, 3, 7 days with 0.1 and 1 microM 9-cis retinoic acid, alone or combined with 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060 or 10 nM EB 1089. In particular, the association of 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM EB 1089 resulted in a synergistic c-myc inhibition, in comparison with that obtained in the presence of the retinoid alone. These findings may have therapeutic implications in human neuroblastoma.