Novel vitamin D analogues; cytotoxic and anti-proliferative activity against a diffuse large B-cell lymphoma cell line and B-cells from healthy donors

The Impact of Exosomes/Microvesicles Derived from Myeloid Dendritic Cells Cultured in the Presence of Calcitriol and Tacalcitol on Acute B-Cell Precursor Cell Lines with MLL Fusion Gene

Vitamin D analogs (VDAs) may directly inhibit the growth of normal and malignant (derived from acute lymphoblastic leukemia (ALL)) B cells, as both types of cells express vitamin D receptor (VDR). We performed anti-proliferative, morphology tests and phenotyping to evaluate the sensitivity of monocytes and iDCs (immature myeloid-derived dendritic cells) on calcitriol and tacalcitol treatment, phenotyping, morphology, and size distribution measurement to determine the characteristics of microvesicles (MVs) and exosomes (EXs) derived from them and, finally, phenotyping and Elisa test to determine the effects of VDAs on modulation of the phenotype of B cells through extracellular vesicles (EVs) released by iDCs. Our results confirmed that both SC cells and iDCs were sensitive to the VDAs and showed altered surface expression of markers associated with monocyte differentiation, which was resulting in the phenotypic changes in EVs derived from them. We also showed that obtained EVs could change the morphology and phenotype of ALL-B-derived precursor cells in a different way, depending on their origin. The differential effect of VDAs on ALL-B cells, which was associated with increased or decreased expression of CD27, CD24, CD38, and CD23 expression, was observed. Hence, further studies to explain the modulation in the composition of EVs by VDAs are required.

Bioavailable 25(OH)D level is associated with clinical outcomes of patients with diffuse large B-cell lymphoma: An exploratory study

BACKGROUNDS & AIMS

Vitamin D insufficiency is associated with worse clinical outcomes in multiple cancer types; however, its roles in diffuse large B-cell lymphoma (DLBCL) patients are still unclear. Here, we aimed to determine the prognostic values of circulating total 25(OH)D and bioavailable 25(OH)D levels in DLBCL patients.

METHODS

A total of 332 newly diagnosed DLBCL patients were recruited. The plasma total 25(OH)D and bioavailable 25(OH)D levels at diagnosis were determined, and their associations with the clinical characteristics and the prognosis of patients were evaluated. The predictive values of clinical characteristics and 25(OH)D levels in the responses to R-CHOP treatments in DLBCL patients were also assessed.

RESULTS

Of the patients, 92.8% had insufficient vitamin D status (<30 ng/mL). Patients with higher plasma bioavailable 25(OH)D were associated with better progression-free survival (PFS, multivariate adjusted-HR = 0.72, 95% CI = 0.38-1.35, P = 0.301, Tertile 2 vs. 1; multivariate adjusted-HR = 0.39, 95% CI = 0.20-0.79, P = 0.009, Tertile 3 vs. 1) and overall survival (OS, multivariate adjusted-HR = 0.89, 95% CI = 0.39-2.02, P = 0.777, Tertile 2 vs. 1; multivariate adjusted-HR = 0.21, 95% CI = 0.07-0.65, P = 0.007, Tertile 3 vs. 1). Meanwhile, higher plasma total 25(OH)D level was significantly associated with better PFS but not OS in DLBCL patients. Besides, DLBCL patients with higher total or bioavailable 25(OH)D levels were more sensitive to the R-CHOP regimen treatments.

CONCLUSION

The bioavailable 25(OH)D level may serve as a novel prognostic biomarker in DLBCL patients.

To D or not to D: vitamin D in hematopoietic cell transplantation

Vitamin D plays an essential role in bone health, immune tolerance, and immune modulation. Autologous and allogeneic hematopoietic cell transplantation (HCT) recipients are at increased risk of vitamin D deficiency, which may increase risks of bone loss and fracture, graft-versus-host disease (GVHD), and relapse, and can delay hematologic and immune recovery following HCT. Growing evidence indicates that vitamin D may have a role as an immunomodulator, and supplementation during HCT may decrease the risk of GVHD, infection, relapse, and mortality. In this paper, we review the role of vitamin D and its association with HCT outcomes and discuss prevention and treatment of vitamin D deficiency after HCT in adult recipients. We review the role of monitoring of vitamin D levels pre- and post-HCT and its supplementation in appropriate patients. We also review the use of bone densitometry prior to HCT and in long-term follow-up and the treatment of osteoporosis in this high-risk population.

Signal Pathways and Therapeutic Prospects of Diffuse Large B Cell Lymphoma

BACKGROUND

Diffuse Large B Cell Lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma which is heterogeneous both clinically and morphologically. Over the past decades, significant advances have been made in the understanding of the molecular genesis, leading to the identification of multiple pathways and molecules that can be targeted for clinical benefit.

OBJECTIVE

The current review aims to present a brief overview of signal pathways of DLBCL, which mainly focus on B-cell antigen Receptor (BCR), Nuclear Factor-κB (NF-κB), Phosphatidylinositol-3-Kinase (PI3K) - protein kinase B (Akt) - mammalian Target of Rapamycin (mTOR), Janus Kinase (JAK) - Signal Transducer and Activator (STAT), Wnt/β-catenin, and P53 pathways.

METHODS

Activation of signal pathways may contribute to the generation, development, chemotherapy sensitivity of DLBCL, and expression of pathway molecules is associated with the prognosis of DLBCL. Some agents targeting these pathways have been proved effective and relevant clinical trials are in progress. These agents used single or combined with chemotherapy/each other might raise the possibility of improving clinical outcomes in DLBCL.

CONCLUSION

This review presents several signal pathways of DLBCL and targeted agents had a tendency to improve the curative effect, especially in high-risk or relapsed/refractory DLBCL.

Antitumor effects and mechanisms of 1,25(OH)2D3 in the Pfeiffer diffuse large B lymphoma cell line

Diffuse large B cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkin lymphoma in China. 1,25-Dihydroxyvitamin D₃ [1,25(OH)₂D₃] has been shown to possess significant antitumor potential and is degraded by 25-hydroxyvitamin D-24-hydroxylase (CYP24A1). In the present study, the role of CYP24A1 and autophagy, and their underlying mechanisms in the anticancer effects of 1,25(OH)₂D₃ in DLBCL cells, were investigated. It was found that the levels of CYP24A1 in DLBCL lymph node tissues were higher than in hyperplasia lymphadenitis tissue. Moreover, the expression of CYP24A1 was positively associated with the Ann Arbor stage and the International Prognostic Index in patients with DLBCL, and negatively associated with the clinical response to treatment. Patients >60 years of age were found to have a higher level of CYP24A1. 1,25(OH)₂D₃ inhibited the proliferation of the Pfeiffer DLBCL cell line and increased the G1 phase population of Pfeiffer cells. Rapamycin (RAPA) in combination with 1,25(OH)₂D₃ increased the G1 phase distribution of Pfeiffer cells. Furthermore, RAPA blocked the increase of CYP24A1 and vitamin D receptor (VDR) expression induced by 1,25(OH)₂D₃. 1,25(OH)₂D₃ induced the formation of autophagosomes, increased the expression of autophagy related protein light chain (LC)3II/LC3I and reduced the expression of the ubiquitin binding protein P62. In addition, 1,25(OH)₂D₃ decreased the phosphorylation of AKT and mammalian target of RAPA (mTOR), and downstream targets eukaryotic translation imitation factor 4E-binding protein 1 and ribosomal protein S6 kinase β-1 in Pfeiffer cells. The results from the present study suggested that CYP24A1 may be a novel prognostic indicator for DLBCL. 1,25(OH)₂D₃ inhibited proliferation and induced autophagy of Pfeiffer cells. In addition, 1,25(OH)₂D₃ increased the G1 phase population of Pfeiffer cells. These effects may be mediated by inhibition of the AKT/mTOR/PI3K signaling pathway. RAPA increased the cell cycle arrest induced by 1,25(OH)₂D₃ by blocking the upregulated expression of CYP24A1 and VDR.

Differential response of lung cancer cell lines to vitamin D derivatives depending on EGFR, KRAS, p53 mutation status and VDR polymorphism

Vitamin D reveals antiproliferative activity against many types of cancer cells. Calcitriol (1,25D3), the most active form of vitamin D3, acts mainly through the vitamin D receptor, regulating the expression of target genes. Cells with reasonable expression of VDR are considered to be sensitive to antiproliferative activity of 1,25D3. However, a few alleles of the VDR gene are correlated with higher or lower response to 1,25D3 treatment. The goal of our study was to establish if cells differing in EGFR, KRAS, p53 mutation status and VDR polymorphism were sensitive to antiproliferative activity of selected vitamin D derivatives (VDDs). In our search for the lead VDD against human lung cancer cells, we selected, for this study, low calcemic analogs of active forms of vitamin D2 and D3 that had previously shown anticancer potential. The selected cell lines revealed differential response to VDDs. The highest proliferation inhibition was observed for EGFR mutant cells while a weaker response was observed for KRAS and/or p53 mutant cells. 24,24-Dihomo-1,25D3 (PRI-1890) showed the highest activity on the VDD-sensitive cell lines (A549, HCC827, NCI-H1299, and NCI-H1703). Therefore, PRI-1890 was selected as the lead VDD for further structure optimization. None of the VDDs used in this study showed antiproliferative activity against A-427 and Calu-3. VDR polymorphisms correlated inversely with sensitivity to the antiproliferative activity of VDDs since we observed less transcriptionally active form of VDR in HCC827 cells sensitive to VDD, while more transcriptionally active form was observed in NCI-H358 cells that were stimulated by VDDs to proliferate. Lack of KRAS and p53 mutations in HCC827 cells may be, therefore, responsible for the higher antiproliferative activity of VDDs, while the presence of KRAS and/or p53 mutations in other cell lines might prevent antiproliferative activity even though the VDDs were transcriptionally active as assessed on increased CYP24A1 expression. VDR gene polymorphism is not directly responsible for the sensitivity of tested cells to VDDs.

Effects of vitamin D3 and its chemical analogs on the growth of Hodgkin's lymphoma, in vitro

Objective

Vitamin D receptor (VDR) activities have been noted for a number of B cell malignancies which showed varying sensitivities to vitamin D3 (1,25-dihydroxyvitamin D3, VD3, calcitriol) and its synthetic analogs. The objective of this study was to address the potential effects of VD3 and vitamin D3 analogs (VDAs) on the growth of Hodgkin’s lymphoma (HL), a malignant pathology of B cell origin, in vitro.

Results

Immunofluorescence staining showed the expression of VDR by primary Hodgkin’s (H) and Reed–Sternberg (RS)—HRS-tumor cells in HL histological sections. Western blot analyses revealed expression of VDR in the HL cell lines Hs445, HDLM2, KMH2, and L428. One-way analysis of variance (ANOVA) on data obtained from water-soluble tetrazolium 1 (WST-1) cell proliferation assay showed decreased cell growth in HDLM2 and L428, 72 h after treatment with 10 µM of either VD3 of VDAs. Western blot analyses showed that treatment of L428 cells with the VDAs (calcipotriol and EB1089) resulted in modest increases in nuclear accumulation of VDR (nuVDR) compared to either dimethyl sulfoxide (DMSO) or VD3 treatments. nuVDR for DMSO control and VD3 was comparable. These results suggest that VD3 or VDAs may affect growth of HL.

Calcitriol and Calcidiol Can Sensitize Melanoma Cells to Low⁻LET Proton Beam Irradiation

Proton beam irradiation promises therapeutic utility in the management of uveal melanoma. Calcitriol (1,25(OH)₂D₃)—the biologically active metabolite of vitamin D₃—and its precursor, calcidiol (25(OH)D₃), exert pleiotropic effects on melanoma cells. The aim of the study was to evaluate the effect of both calcitriol and calcidiol on melanoma cell proliferation and their response to proton beam irradiation. Three melanoma cell lines (human SKMEL-188 and hamster BHM Ma and BHM Ab), pre-treated with 1,25(OH)₂D₃ or 25(OH)D₃ at graded concentrations (0, 10, 100 nM), were irradiated with 0–5 Gy and then cultured in vitro. Growth curves were determined by counting the cell number every 24 h up to 120 h, which was used to calculate surviving fractions. The obtained survival curves were analysed using two standard models: linear-quadratic and multi-target single hit. Calcitriol inhibited human melanoma proliferation at 10 nM, while only calcidiol inhibited proliferation of hamster lines at 10 and 100 nM doses. Treatment with either 1,25(OH)₂D₃ or 25(OH)D₃ radio sensitized melanoma cells to low doses of proton beam radiation. The strength of the effect increased with the concentration of vitamin D₃. Our data suggest that vitamin D₃ may be an adjuvant that modifies proton beam efficiency during melanoma therapy.

Primary diffuse large B-cell lymphoma in the maxilla: A case report

RATIONALE

Lymphomas are the second most common non-epithelial malignant tumors in the oral and maxillofacial region. Non-Hodgkin's lymphoma (NHL) develops at extranodal sites, and cases involving the maxilla account for less than 1% of all NHLs. We describe a case of diffuse large B-cell lymphoma (DLBCL) in the maxilla, and highlight the clinical signs, symptoms, differential diagnosis, and appropriate treatment of DLBCL in the oral cavity and maxillofacial region.

PATIENT CONCERNS

A 67-year-old woman was admitted to our surgical department with pain and swelling in her right upper posterior teeth for about six months. She was previously misdiagnosed with periodontal disease and had a history of tooth extraction.

DIAGNOSES

Computed tomography (CT) scan revealed extensive osteolysis in the right posterior part of the maxilla with enhanced neoplasm. A solid mass was found upon incisional biopsy, and immunohistochemistry confirmed the diagnosis of DLBCL.

INTERVENTIONS

The patient was treated with six courses of rituximab, cyclophosphamide, pirarubicin, vincristine, and prednisolone (R-CHOP), followed by external irradiation treatment.

OUTCOMES

The treatment was well tolerated, and the patient is presently alive after two years of follow-up.

LESSONS

Non-specific symptoms, such as unclear primary dental pain and unresolved periapical swelling, can make an accurate diagnosis of DLBCL difficult, which frequently lead to delayed diagnosis. A CT or cone beam computed tomography (CBCT) scan of the maxilla and immunohistochemical staining of the biopsy specimen is recommended. Combination therapy including radiotherapy and chemotherapy is the optimal treatment for NHL.

Health Risks of Hypovitaminosis D: A Review of New Molecular Insights

Hypovitaminosis D has become a pandemic, being observed in all ethnicities and age groups worldwide. Environmental factors, such as increased air pollution and reduced ultraviolet B (UVB) irradiation, as well as lifestyle factors, i.e., decreased outdoor activities and/or poor intake of vitamin D-rich food, are likely involved in the etiology of a dramatic reduction of vitamin D circulating levels. The insufficiency/deficiency of vitamin D has long been known for its association with osteoporosis and rickets. However, in the last few decades it has become a serious public health concern since it has been shown to be independently associated with various chronic pathological conditions such as cancer, coronary heart disease, neurological diseases, type II diabetes, autoimmune diseases, depression, with various inflammatory disorders, and with increased risk for all-cause mortality in the general population. Prevention strategies for these disorders have recently involved supplementation with either vitamin D2 or vitamin D3 or their analogs at required daily doses and tolerable upper-limit levels. This review will focus on the emerging evidence about non-classical biological functions of vitamin D in various disorders.

Vitamin D Receptor Expression in Plasmablastic Lymphoma and Myeloma Cells Confers Susceptibility to Vitamin D

Plasmablastic B-cell malignancies include plasmablastic lymphoma and subsets of multiple myeloma and diffuse large B-cell lymphomaDLBCL. These diseases can be difficult to diagnose and treat, and they lack well-characterized cell line models. Here, immunophenotyping and FOXP1 expression profiling identified plasmablastic characteristics in DLBCL cell lines HLY-1 and SU-DHL-9, associated with CTNNAL1, HPGD, RORA, IGF1, and/or vitamin D receptor (VDR) transcription. We demonstrated VDR protein expression in primary plasmablastic tumor cells and confirmed in cell lines expression of both VDR and the metabolic enzyme CYP27B1, which catalyzes active vitamin D3 production. Although Vdr and Cyp27b1 transcription in normal B cells were activated by interleukin 4 (IL-4) and CD40 signaling, respectively, unstimulated malignant plasmablastic cells lacking IL-4 expressed both VDR and CYP27B1. Positive autoregulation evidenced intact VDR function in all plasmablastic lines, and inhibition of growth by active vitamin D3 was both dependent on MYC protein inhibition and could be enhanced by cotreatment with a synthetic ROR ligand SR-1078. Furthermore, a VDR polymorphism, FOK1, was associated with greater vitamin D3-dependent growth inhibition. In summary, HLY-1 provides an important model of strongly plasmablastic lymphoma, and disruption of VDR pathway activity may be of therapeutic benefit in both plasmablastic lymphoma and myeloma.

Vitamin D in hematological disorders and malignancies

Commonly known for its critical role in calcium homeostasis and bone mineralization, more recently vitamin D has been implicated in hematological cancer pathogenesis and shows promise as an anti-cancer therapy. Serum levels of 25(OH)D₃ , the precursor to the active form of vitamin D, calcitriol, are frequently lower in patients with hematological disease compared to healthy individuals. This often correlates with worse disease outcome. Furthermore, diseased cells typically highly express the vitamin D receptor, which is required for many of the anti-cancer effects observed in multiple in vivo and in vitro cancer models. In abnormal hematological cells, vitamin D supplementation promotes apoptosis, induces differentiation, inhibits proliferation, sensitizes tumor cells to other anti-cancer therapies, and reduces the production of pro-inflammatory cytokines. Although the dosage of vitamin D required to achieve these effects may induce hypercalcemia in humans, analogs and combinatorial treatments have been developed to circumvent this side effect. Vitamin D and its analogs are well tolerated in clinical trials, and thus, further investigation into the use of these agents in the clinic is warranted. Here, we review the current literature in this field.