Antiproliferative effects of the biologically active metabolite of vitamin D3 (1,25 [OH]2 D3) on head and neck squamous cell carcinoma cell lines

Vitamin D in Head and Neck Cancer: a Systematic Review

PURPOSE OF REVIEW

Observational studies have shown that serum 25-OH vitamin D [25(OH)D] is inversely associated with overall cancer risk in many malignancies. We performed a systematic literature review to determine whether vitamin D deficiency is related to head and neck cancer (HNC) etiology and outcome.

RECENT FINDINGS

The search yielded five prospective studies reporting 25(OH)D levels prior to cancer diagnosis and their effect on the risk of HNC. Eight studies were cross-sectional or case-control studies, in which 25(OH)D levels were only measured after cancer diagnosis. Two studies found an inverse association between 25(OH)D level and HNC risk, while two other prospective cohort studies demonstrated no connection between 25(OH)D and HNC risk. Several studies reported cancer patients to have significantly lower 25(OH)D levels than controls. Associations between 25(OH)D and prognosis and mortality were variable. The link between vitamin D and HNC has so far only been investigated in a few observational, prospective, and case-control studies. Vitamin D deficiency may be more common in HNC patients than in the healthy population. There is no evidence for a causal relationship. Further studies are needed to evaluate whether low 25(OH)D concentrations play a role in the development or outcome of HNCs.

Regulation of the Immune Balance During Allogeneic Hematopoietic Stem Cell Transplantation by Vitamin D

One of the most promising therapeutic approaches for numerous hematological malignancies represents the allogeneic hematopoietic stem cell transplantation (allo-HSCT). One major complication is the development of the life-threatening graft-vs.-host disease (GvHD) which limits beneficial effects of graft-vs.-leukemia (GvL) responses during allo-HSCT. Strengthening GvL effects without induction of severe GvHD is essential to decrease the relapse rate after allo-HSCT. An interesting player in this context is vitamin D₃ since it has modulatory capacity in both preventing GvHD and boosting GvL responses. Current studies claim that vitamin D₃ induces an immunosuppressive environment by dendritic cell (DC)-dependent generation of regulatory T cells (Tregs). Since vitamin D₃ is known to support the antimicrobial defense by re-establishing the physical barrier as well as releasing defensins and antimicrobial peptides, it might also improve graft-vs.-infection (GvI) effects in patients. Beyond that, alloreactive T cells might be attenuated by vitamin D₃-mediated inhibition of proliferation and activation. Despite the inhibitory effects of vitamin D₃ on T cells, anti-tumor responses of GvL might be reinforced by vitamin D₃-triggered phagocytic activity and antibody-based immunotherapy. Therefore, vitamin D₃ treatment does not only lead to a shift from a pro-inflammatory toward a tolerogenic state but also promotes tumoricidal activity of immune cells. In this review we focus on vitamin D₃ and its immunomodulatory effects by enhancing anti-tumor activity while alleviating harmful allogeneic responses in order to restore the immune balance.

Role of vitamin D and vitamin D receptor (VDR) in oral cancer

Oral cancer is known as one of the most common cancers, with a poor prognosis, related to delayed clinical diagnosis, either due to the lack of particular biomarkers related to the disease or costly therapeutic alternatives. Vitamin D executes its functions by interacting with the vitamin D receptor (VDR), both in healthy and diseased individuals, including oral cancer. This review discusses the role of vitamin D and VDR on tumorigenesis, emphasizing on oral cancer. Furthermore, regulation of VDR expression, mechanisms of anticancer effects of calcitriol, oral cancer chemoresistance and its relation with VDR and polymorphisms of VDR gene will be discussed. The manuscript is prepared mainly using the information collected from PubMed and MEDLINE.

Expression of vitamin D receptor and vitamin D status in patients with oral neoplasms and effect of vitamin D supplementation on quality of life in advanced cancer treatment

AIM OF THE STUDY

Vitamin D receptor (VDR) expression and serum vitamin D scores in oral premalignant lesions and oral cancer have not been widely analyzed. The role of vitamin D supplementation in advanced oral cancer for improving quality of life (QOL) is also a matter of research.

MATERIAL AND METHODS

Vitamin D receptor expression and vitamin D scores were analyzed in normal oral mucosa (n = 95), leukoplakia (n = 23) and oral cancer (n = 87). 45 patients with advanced oral cancer subjected to chemoradiation were evaluated for the effect of vitamin D supplementation on most observable QOL parameters such as oral mucositis, swallowing performance and overall QOL.

RESULTS

Vitamin D receptor expression was increased in oral neoplastic lesions. Vitamin D scores were significantly lower in cases compared to healthy controls (p = 0.002). Vitamin D supplementation significantly reduced the therapy-related toxicities in advanced cancer, thus reducing morbidity and improving QOL.

CONCLUSIONS

Vitamin D receptor expression is increased in premalignant lesions and oral cancer. Vitamin D insufficiency and deficiency are prevalent in patients with oral neoplastic lesions. Vitamin D supplementation has a role in reducing treatment-related toxicities, especially in advanced cancer.

Chemotherapy-induced alopecia management: Clinical experience and practical advice

BACKGROUND

Chemotherapy-induced alopecia (CIA) is probably one of the most shocking aspects for oncological patients and underestimated by physicians. Among hair loss risk factors, there are treatment-related aspects such as drug dose, administration regimen, and exposure to X-rays, but also patient-related characteristics. To the best of our knowledge, no guidelines are available about CIA management.

AIMS AND METHODS

With this study, based on literature background and our clinical experience, we would like to propose a list of actions in order to estimate the risk of hair loss before starting chemotherapy and to manage this condition before, during, and after drug administration and to create a sort of practical guide for dermatologists and oncologists.

RESULTS AND CONCLUSION

There is an urgent need for prospective studies to clarify the mechanistic basis of alopecia associated with these drugs and consequently to design evidence-based management strategies.

Serum vitamin D levels of patients with oral squamous cell carcinoma (OSCC) and expression of vitamin D receptor in oral precancerous lesions and OSCC

Background: Resistance to programmed cell death (apoptosis) is a crucial factor for the carcinogenesis of oral squamous cell carcinoma (OSCC). Vitamin D (calcitriol) may overcome apoptosis resistance in tumor cells of OSCC. Vitamin D receptor (VDR) expression in oral precancerous lesions of OSCC has not been analyzed and serum vitamin D level seems to be a predictor of cancer development. Material and Methods: Expression of VDR was analyzed in normal oral mucosa (n=5), oral precursor lesions (simple hyperplasia, n=11; squamous intraepithelial neoplasia, SIN I-III, n=35), and OSCC specimen (n=42) by immunohistochemistry (IHC). Moreover, serum vitamin D levels were measured by 25(OH)D3 (calcidiol) in patients with OSCC (n=42) and correlated with IHC results. Results: Expression of VDR was significantly increased in precancerous and OSCC compared with normal tissue. Compared with SIN I-III lesions VDR expression significantly decreased in OSCC. Severe vitamin D deficiency was detected in our OSCC patient cohort but there was no significant correlation analyzed between serum vitamin D levels and corresponding immunohistochemically detected VDR expression in OSCC. Conclusions: Our survey provides the first evidence of VDR expression in precancerous lesions of OSCC. Apoptosis induction of VDR+ cells in oral precancerous lesions and OSCC by natural vitamin D or synthetic vitamin D compounds could be useful for chemoprevention. Moreover, systemically and/or locally applied, these compounds may act as sensitizers for apoptosis mediated by radio-, and chemotherapy treatment in OSCC.

Key words:Oral cancer, oral precancer, lichen planus, leukoplakia, apoptosis, serum 25(OH)D3, vitamin D receptor, chemoprevention, multistep carcinogenesis.

Vitamin D receptor, CYP27B1 and CYP24A1 genes polymorphisms association with oral cancer risk and survival

BACKGROUND

Genetic polymorphisms of vitamin D receptor gene (VDR) and genes involved in vitamin D metabolism pathway, CYP27B1 and CYP24B1, may affect individual susceptibility to oral squamous cell carcinoma. The purpose of this study was to evaluate the associations between VDR, CYP27B1 and CYP24A1 gene polymorphisms with oral cancer risk and survival.

METHODS

Study cohort consisted of 110 patients with oral cancer and 122 healthy controls. The genotypes of the analysed genes were determined by PCR-RFLP or real-time PCR method.

RESULTS

The significant decrease of oral cancer risk was observed in individuals with heterozygote genotype of CYP24A1 gene (rs2296241) (odds ratio 0.281, P = 0.000) in comparison with wild type. Patients with VDR FokI ff wild type genotype had significantly worse overall survival (P = 0.012, log rank) compared with heterozygous and mutated genotype combined. A stratified analysis by the lymph node involvement and tumour stage showed that ff is associated with poor survival in groups with and without lymph node involvement (P = 0.025, P = 0.040, respectively) and in stage III tumours (P = 0.026). Multivariate Cox's regression analysis revealed that VDR FokI could be considered an independent prognostic factor.

CONCLUSION

Our findings indicate that CYP24A1 gene polymorphism might have an influence on the susceptibility to oral cancer. VDR FokI polymorphism was associated with worse survival and could be considered as an independent prognostic marker.

Vitamin D deficiency promotes human breast cancer growth in a murine model of bone metastasis

Vitamin D exerts antiproliferative, prodifferentiation, and proapoptotic effects on nonclassic target tissues such as breast. Blood levels of 25-hydroxyvitamin D [25(OH)D], the most sensitive indicator of vitamin D status, are inversely correlated with breast cancer risk; however, a causal relationship between vitamin D deficiency and breast cancer growth in bone has not been assessed. We examined the effect of vitamin D deficiency on the intraskeletal growth of the human breast cancer cell line MDA-MB-231-TxSA in a murine model of malignant bone lesions. Subsets of mice were treated concurrently with osteoprotegerin (OPG) to abrogate bone resorption. Outcomes were assessed by repeated radiographic and end-point micro-computed tomography and histologic analyses. Mice weaned onto a vitamin D-free diet developed vitamin D deficiency within 4 weeks [mean +/- SE serum 25(OH)D: 11.5 +/- 0.5 nmol/L], which was sustained throughout the study and was associated with secondary hyperparathyroidism and accelerated bone turnover. Osteolytic lesions appeared earlier and were significantly larger in vitamin D-deficient than in vitamin D-sufficient mice after 2 weeks (radiographic osteolysis: +121.5%; histologic tumor area: +314%; P < 0.05). Although OPG treatment reduced the size of radiographic osteolyses and tumor area in both groups, tumors remained larger in OPG-treated vitamin D-deficient compared with OPG-treated vitamin D-sufficient mice (0.53 +/- 0.05 mm(2) versus 0.19 +/- 0.05 mm2; P < 0.05). We conclude that vitamin D deficiency promotes the growth of human breast cancer cells in the bones of nude mice. These effects are partly mediated through secondary changes in the bone microenvironment, along with direct effects of vitamin D on tumor growth.

The calcitriol analogue EB1089 impairs alveolarization and induces localized regions of increased fibroblast density in neonatal rat lung

The active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3, or calcitriol), is a potent mitogen for fibroblasts cultured from rat lungs at postnatal day 4 (P4), during the peak of septation (P3 to P7). In light of the key role of fibroblasts in alveolar septation, the authors conducted studies to measure the extent to which 1,25-(OH)2D3 affects lung maturation in vivo, as well as its ability to influence the stimulatory activity of all-trans retinoic acid (RA). To identify a calcitriol analogue with maximal mitogenic activity and low systemic toxicity, two compounds with reduced calcemic activity (EB1089 and CB1093) and a superagonist (MC1288) were evaluated in neonatal rat lung fibroblast cultures. All 3 analogues were more potent mitogens than 1,25-(OH)(2)D3 itself (MC1288 approximately CB1093 > EB1089 > 1,25-(OH)2D3). In addition, each was more effective than 1,25-(OH)2D3(EB1089 > CB1093 > MC1288 > 1,25-(OH)2D3) in the activation of a vitamin D response element from the platelet-derived growth factor (PDGF)-A gene, whose expression is essential for normal alveolarization. Daily administration of EB1089 to rats 4 to 12 days of age caused an increase in mean alveolar chord length (P < .0001), and also elicited prominent regions of fibroblast hypercellularity, as defined in terms of a vimentin-positive, factor VIII-negative phenotype. EB1089 and RA each induced the expression of 2 important lung structural proteins, collagen and elastin. Regions of fibroblast hypercellularity induced by EB1089 were strongly positive for expression of the alveolarization-relevant growth factors, PDGF-AA and vascular endothelial growth factor (VEGF). These studies demonstrate that 1,25-(OH)2D3 disrupts the overall alveolarization process in the neonatal lung, although it stimulates expression of some proteins associated with lung morphogenesis.

Studies of the effects of 1,25-dihydroxyvitamin D on skeletal and calcium homeostasis and on inhibition of tumor cell growth

Vitamin D, parathyroid hormone (PTH), and parathyroid hormone-related peptide (PTHrP) are major regulators of calcium metabolism and vitamin D can also reduce the growth of normal cells and tumor cells. PTHrP and PTH act via a common membrane receptor (PTHR). The mouse PTHR is regulated by a kidney-selective upstream promoter P(1) and ubiquitous downstream promoter P(2). In vitro and in vivo 1,25(OH)(2)D can inhibit PTHR expression in bone but not cartilage by downregulating transcription via P(2). Gene transcription of PTHrP per se can also be downregulated by 1,25(OH)(2)D and by low calcemic vitamin D analogs. This inhibitory effect may reduce the hypercalcemia caused by overproduction of PTHrP by tumor cells. In a malignant keratinoctye cell line, phosphorylation of the retinoid X receptor alpha occurs through the activated Ras-MAP kinase pathway and results in attenuated trans-activation by the vitamin D receptor, its heterodimeric partner. This decreases the growth-inhibitory efficacy of 1,25(OH)(2)D. Studies of the capacity of vitamin D to alter PTHrP production and action and of its anti-proliferative effects can, therefore, shed important light on basic mechanisms controlling these events, and may also have major implications for clinical medicine and therapeutics.

Altered response of a human squamous cell carcinoma cell line to 1, 25-dihydroxyvitamin D(3) after transfer of a normal chromosome 11

Previous work in our laboratory using functional assays for tumorigenicity identified a tumor suppressor element on human chromosome 11q for the cutaneous squamous cell carcinoma cell line A388.6TG.c2. In this report, we screened a variety of agents for differential effects on A388.6TG.c2 compared to a growth-suppressed chromosome 11 microcell hybrid of A388.6TG.c2. One of the agents, 1, 25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3); calcitriol), exerted a growth-altering effect on A388.6TG.c2, which formed rounded cell clusters across the surface of the raft by Day 6 of treatment. In contrast, full-length chromosome 11 hybrids of A388.6TG.c2, as well as two other squamous cell carcinoma cell lines (FaDu and A431), when treated with 1,25(OH)(2)D(3), failed to demonstrate this cell-clumping phenotype. To pursue the hypothesis that the growth suppressor element is involved in altering the response to 1, 25(OH)(2)D(3), we tested microcell hybrids carrying t(X;11) chromosomes lacking large portions of 11q. Although these hybrids, like the parent A388.6TG.c2 cells, demonstrated extensive growth in organotypic cultures, they failed to form cell clusters with 1, 25(OH)(2)D(3) treatment. These results suggest that the chromosome 11 element that alters the response to 1,25(OH)(2)D(3) is distinct from the growth-suppressing element. An examination of differentiation marker expression revealed identical patterns of basal and suprabasal markers for A388.6TG.c2 and for a chromosome 11 hybrid with or without treatment with 1,25(OH)(2)D(3). Finally, characterization of candidate tumor suppressor gene PPP2R1B, which encodes for a subunit of protein phosphatase 2A (PP2A), showed seemingly insignificant alterations by cDNA sequence analysis. Collectively, the data suggest that human chromosome 11 contains two different tumor suppressor elements that may account for the two areas of loss of heterozygosity observed on the long arm of this chromosome.

Mitogen-activated protein kinase inhibits 1,25-dihydroxyvitamin D3-dependent signal transduction by phosphorylating human retinoid X receptor alpha

Human retinoid X receptor alpha (hRXR alpha) is a member of the nuclear receptor family of transcriptional regulators. It regulates transcription through its association with several heterodimeric partners, including the vitamin D3 receptor (VDR). Signaling through the VDR is essential for normal calcium homeostasis and has been shown to inhibit the proliferation of cancer cells derived from a number of tissues. Here we show that phosphorylation of hRXR alpha in ras-transformed human keratinocytes through the activated Ras-Raf-mitogen-activated protein kinase (Ras-Raf-MAP kinase) pathway results in attenuated transactivation by the VDR and resistance to the growth inhibitory action of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] and RXR-specific agonist LG1069 (4-[1-(5,6,7, 8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphthalenyl) ethenyl]-benzoic acid). Phosphorylation of hRXR alpha occurs at serine 260, a consensus MAP kinase site. Inhibition of MAP kinase activity or point mutagenesis of serine 260 of hRXR alpha reverses the observed resistance to 1,25(OH)2D3 and LG1069. Thus, hRXR alpha is a downstream target of MAP kinase, and its phosphorylation may play an important role in malignant transformation.

Low glutamine concentrations induce phenotypical and functional differentiation of U937 myelomonocytic cells

L-Glutamine is the most abundant free amino acid of the human body and is essential for the culture of many cell types. Clinically, reduction of glutamine by administration of glutaminase or the use of glutamine analogs is a common therapy for patients with acute lymphocytic leukemia. In the current study, we investigated the influence of glutamine concentrations on the human myelomonocytic cell line U937. Decreasing the glutamine concentration evoked a reduction in DNA synthesis (R2 = 0.9885, P < 0.0001), increased cell volume (P < 0.01) and the cytoplasm/nuclear ratio, and enhanced the development of vacuoles but did not influence cell viability. Culturing cells in reduced concentrations of glutamine augmented the percentage of cells expressing CD64 (Fc receptor for IgG/FcgammaRI, P < 0.01), CD11b (complement receptor type 3/CR3, P < 0.001) and CD71 (transferrin receptor, P < 0.05). The percentage of U937 cells expressing CD23 (low affinity receptor for IgE/FcepsilonRII) was increased at low concentrations of glutamine at both the protein (P < 0.01) and mRNA levels. The percentage of U937 cells phagocytizing opsonized E. coli (P < 0.001) or latex particles (P < 0.001) was enhanced by lowering the glutamine concentration. In conclusion, reducing glutamine concentration causes differentiation of the cell line U937 along the monocytic pathway. These effects may indicate a mechanistic basis for prior published evidence that glutaminase and glutamine antagonists are effective anti-tumor agents.