calcitriol and Lung-Neoplasms

In the alpha-Tocopherol, beta-Carotene Cancer Prevention (ATBC) study, a large randomized placebo-controlled trial designed to test the cancer prevention effects of alpha-tocopherol (50 mg/day) and beta-carotene (20 mg/day), participants receiving supplemental beta-carotene had significantly higher rates of lung cancer than those not receiving beta-carotene. It has been hypothesized that the supplemental beta-carotene may have interfered with the synthesis of vitamin D and that the resulting lower concentrations of vitamin D contributed to the elevated cancer incidence. We evaluated whether supplementation with beta-carotene altered the serum concentrations of either 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D in the ATBC Study, by comparing on-study changes between baseline and follow-up serum samples among 20 randomly selected matched pairs of subjects from the beta-carotene and placebo groups. In a matched-pair analysis, the difference between the changes in both 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in the beta-carotene supplement and placebo groups were small and statistically nonsignificant. These results provide no evidence that beta-carotene supplementation interferes with the endogenous production of 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D and suggest that it is unlikely that an interaction between supplemental beta-carotene and vitamin D metabolites contributed to the modest increase in lung cancer incidence observed in the ATBC Study.

Topics: Age Factors; Antioxidants; beta Carotene; Drug Interactions; Follow-Up Studies; Humans; Incidence; Lung Neoplasms; Matched-Pair Analysis; Placebos; Seasons; Statistics, Nonparametric; Time Factors; Vitamin D

Vitamin D deficiency is associated with poor cancer outcome in humans, and administration of vitamin D or its analogs decreases tumor progression and metastasis in animal models. Using the mouse mammary tumor virus-polyoma middle T antigen (MMTV-PyMT) model of mammary cancer, we previously demonstrated a significant acceleration of carcinogenesis in animals on a low vitamin D diet and a reduction in spontaneous lung metastases when mice received vitamin D through perfusion. We investigate here the action mechanism for vitamin D in lung metastasis in the same non-immunodeficient model and demonstrate that it involves the control of epithelial to mesenchymal transition as well as interactions between chemokine C-X-C motif chemokine 12 (CXCL12) and its receptor C-X-C chemokine receptor type 4 (CXCR4). In vitro, 10-9M vitamin D treatment modifies the phenotype of MMTV-PyMT primary mammary tumor cells and significantly decreases their invasiveness and mammosphere formation capacity by 40% and 50%, respectively. Vitamin D treatment also inhibits phospho-signal transducer and activator of transcription 3 (p-STAT3), zinc finger E-box-binding homeobox 1 (Zeb1), and vimentin by 52%, 75%, and 77%, respectively, and increases E-cadherin by 87%. In vivo, dietary vitamin D deficiency maintains high levels of Zeb1 and p-STAT3 in cells from primary mammary tumors and increases CXCL12 expression in lung stroma by 64%. In lung metastases, vitamin D deficiency increases CXCL12/CXCR4 co-localization by a factor of 2.5. These findings indicate an involvement of vitamin D in mammary cancer "seed" (primary tumor cell) and "soil" (metastatic site) and link vitamin D deficiency to epithelial-to-mesenchymal transition (EMT), CXCL12/CXCR4 signaling, and accelerated metastasis, suggesting vitamin D repleteness in breast cancer patients could enhance the efficacy of co-administered therapies in preventing spread to distant organs.

Topics: Animals; Cell Line, Tumor; Chemokine CXCL12; Epithelial-Mesenchymal Transition; Female; Lung Neoplasms; Mammary Neoplasms, Experimental; Mice; Neoplasm Invasiveness; Receptors, CXCR4; Signal Transduction; Vitamin D; Vitamin D Deficiency

Seminomas have been rarely associated with malignant hypercalcemia. The responsible mechanism of hypercalcemia in this setting has been described to be secondary to 1,25-dihydroxyvitamin D secretion. The relationship with PTHrP has not been determined or studied.The aim of this study is to describe and discuss the case and the pathophysiological mechanisms involved in a malignant hypercalcemia mediated by 1,25-dihydroxyvitamin D and PTHrP cosecretion in a patient with seminoma.. A 35-year-old man was consulted for assessment and management of severe hypercalcemia related to an abdominal mass. Nausea, polyuria, polydipsia, lethargy and confusion led him to the emergency department. An abdominal and pelvic enhanced CT confirmed a calcified pelvic mass, along with multiple retroperitoneal lymphadenopathy. Chest x-ray revealed "cannon ball" pulmonary metastases. The histopathology result was consistent with a seminoma. Serum calcium was 14.7 mg/dl, PTH was undetectable, 25-dihydroxyvitamin D was within normal values and PTHrP and 1,25-dihydroxyvitamin were elevated (35.0 pg/ml, and 212 pg/ml, respectively). After the first cycle of chemotherapy with bleomycin, etoposide and cisplatin, normocalcemia was restored. Both PTHrP and 1,25-dihydroxyvitamin D, dropped dramatically to 9.0 pg/ml and 8.0 pg/ml, respectively.. The association of seminoma and malignant hypercalcemia is extremely rare. We describe a case of a patient with a seminoma and malignant hypercalcemia related to paraneoplastic cosecretion of 1,25-dihydroxyvitamin D and PTHrP. After successful chemotherapy, calcium, PTHrP and 1,25-Dihydroxyvitamin D returned to normal values.

Topics: Adult; Humans; Hypercalcemia; Lung Neoplasms; Male; Paraneoplastic Syndromes; Parathyroid Hormone; Parathyroid Hormone-Related Protein; Prognosis; Seminoma; Testicular Neoplasms; Vitamin D

1α,25-Dihydroxyvitamin D3 (1,25-D3) is antiproliferative in preclinical models of lung cancer, but in tumor tissues, its efficacy may be limited by CYP24A1 expression. CYP24A1 is the rate limiting catabolic enzyme for 1,25-D3 and is overexpressed in human lung adenocarcinoma (AC) by unknown mechanisms.. The DNA methylation status of CYP24A1 was determined by bisulfite DNA pyrosequencing in a panel of 30 lung cell lines and 90 surgically resected lung AC. The level of CYP24A1 methylation was correlated with CYP24A1 expression in lung AC cell lines and tumors. In addition, histone modifications were assessed by quantitative chromatin immunoprecipitation-polymerase chain reaction (ChIP-qPCR) in A549, NCI-H460, and SK-LU-1.. Bisulfite DNA pyrosequencing analysis revealed that CYP24A1 gene was heterogeneously methylated in lung AC. Expression of CYP24A1 was inversely correlated with promoter DNA methylation in lung AC cell lines and tumors. Treatment with 5-aza-2'-deoxycytidine (5-Aza) and trichostatin A (TSA) increased CYP24A1 expression in lung AC. We observed that CYP24A1 promoter hypermethylation decreased CYP24A1 enzyme activity in vitro, whereas treatment with 5-Aza and/or TSA increased CYP24A1 enzyme affinity for its substrate 1,25-D3. In addition, ChIP-qPCR analysis revealed specific histone modifications within the CYP24A1 promoter region. Treatment with TSA increased H3K4me2 and H3K9ac and simultaneously decreased H3K9me2 at the CYP24A1 promoter and treatment with 5-Aza and/or TSA increased the recruitment of vitamin D receptor (VDR) to vitamin D response elements (VDRE) of the CYP24A1 promoter.. The expression of CYP24A1 gene in human lung AC is in part epigenetically regulated by promoter DNA methylation and repressive histone modifications. These findings should be taken into consideration when targeting CYP24A1 to optimize antiproliferative effects of 1,25-D3 in lung AC.

Topics: Adenocarcinoma; Aged; Blotting, Western; Chromatin Immunoprecipitation; DNA Methylation; Enzyme-Linked Immunosorbent Assay; Epigenesis, Genetic; Female; Flow Cytometry; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Male; Neoplasm Recurrence, Local; Neoplasm Staging; Prognosis; Promoter Regions, Genetic; Real-Time Polymerase Chain Reaction; Receptors, Calcitriol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Survival Rate; Tumor Cells, Cultured; Vitamin D; Vitamin D3 24-Hydroxylase

The vitamin D(3) catabolizing enzyme, CYP24, is frequently over-expressed in tumors, where it may support proliferation by eliminating the growth suppressive effects of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)). However, the impact of CYP24 expression in tumors or consequence of CYP24 inhibition on tumor levels of 1,25(OH)(2)D(3)in vivo has not been studied due to the lack of a suitable quantitative method. To address this need, an LC-MS/MS assay that permits absolute quantitation of 1,25(OH)(2)D(3) in plasma and tumor was developed. We applied this assay to the H292 lung tumor xenograft model: H292 cells eliminate 1,25(OH)(2)D(3) by a CYP24-dependent process in vitro, and 1,25(OH)(2)D(3) rapidly induces CYP24 expression in H292 cells in vivo. In tumor-bearing mice, plasma and tumor concentrations of 1,25(OH)(2)D(3) reached a maximum of 21.6 and 1.70ng/mL, respectively, following intraperitoneal dosing (20μg/kg 1,25(OH)(2)D(3)). When co-administered with the CYP24 selective inhibitor CTA091 (250μg/kg), 1,25(OH)(2)D(3) plasma levels increased 1.6-fold, and tumor levels increased 2.6-fold. The tumor/plasma ratio of 1,25(OH)(2)D(3) AUC was increased 1.7-fold by CTA091, suggesting that the inhibitor increased the tumor concentrations of 1,25(OH)(2)D(3) independent of its effects on plasma disposition. Compartmental modeling of 1,25(OH)(2)D(3) concentration versus time data confirmed that: 1,25(OH)(2)D(3) was eliminated from plasma and tumor; CTA091 reduced the elimination from both compartments; and that the effect of CTA091 on tumor exposure was greater than its effect on plasma. These results provide evidence that CYP24-expressing lung tumors eliminate 1,25(OH)(2)D(3) by a CYP24-dependent process in vivo and that CTA091 administration represents a feasible approach to increase tumor exposure to 1,25(OH)(2)D(3).

Topics: Animals; Area Under Curve; Cell Line, Tumor; Chromatography, Liquid; Enzyme Inhibitors; Feasibility Studies; Female; Gene Expression Regulation, Enzymologic; Humans; Lung Neoplasms; Mass Spectrometry; Mice; Mice, Nude; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Steroid Hydroxylases; Vitamin D; Vitamin D3 24-Hydroxylase; Vitamins; Xenograft Model Antitumor Assays

1alpha,25-Dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], the major regulator of calcium homeostasis, has potent antiproliferative and anti-invasive properties in vitro in cancer cells. Studies in vivo demonstrated that 1alpha,25(OH)(2)D(3) slows the progression of breast, prostate and other carcinomas. A key question is whether 1alpha,25(OH)(2)D(3) exerts its anticarcinogenic effects in vivo by a mechanism that is dependent on its capacity to limit the proliferation and invasiveness of cancer cells in vitro. It has not been clear whether the calcemic activity and regulation of the host defenses by 1alpha,25(OH)(2)D(3) contribute to the effect on cancer cells. In this study we have focused on the influence of 1alpha,25(OH)(2)D(3) on the metastasis of lung cancer, without involvement of the calcemic activity and other effects of 1alpha,25(OH)(2)D(3) in the host. We used metastatic Lewis lung carcinoma cells expressing green fluorescent protein (LLC-GFP cells) and examined metastatic activity in vitamin D receptor (VDR) null mutant (VDR(-/-)) mice and their wild-type counterparts (VDR(+/+) mice). VDR(-/-) mice exhibit hypocalcemia and extremely high serum levels of 1alpha,25(OH)(2)D(3). We expected that serum 1alpha,25(OH)(2)D(3) would act in vivo to directly inhibit the metastatic growth of VDR-positive LLC-GFP cells in VDR(-/-) mice. The metastatic activities of LLC-GFP cells were remarkably reduced in VDR(-/-) mice compared with VDR(+/+) mice. To test the hypothesis that serum 1alpha,25(OH)(2)D(3) is an intrinsic factor that inhibits metastatic growth of lung cancer cells, we corrected hypocalcemia and/or hypervitaminosis D in VDR(-/-) mice by dietary manipulation. The metastatic growth of LLC-GFP cells was remarkably reduced in response to serum levels of 1alpha,25(OH)(2)D(3), but not to serum calcium levels. Furthermore, we found that VDR(+/+) mice fed the manipulated diets displayed an apparent inverse relationship between the physiological levels of serum 1alpha,25(OH)(2)D(3) (8-15 pg/ml) and tumorigenesis. Here we show that 1alpha,25(OH)(2)D(3) inhibits the metastatic growth of lung cancer cells in a defined animal model.

Topics: Animals; Calcium; Cell Proliferation; Diet; Green Fluorescent Proteins; Hypocalcemia; Lung Neoplasms; Mice; Mice, Knockout; Receptors, Calcitriol; Tumor Cells, Cultured; Vitamin D