seocalcitol and Adenocarcinoma

Parathyroid hormone-related protein (PTHrP) plays a major role in prostate carcinoma progression and bone metastasis. Once prostate cancers become androgen-independent, treatment options become limited. Vitamin D analogues represent a potentially valuable class of agents in this clinical context. Using the prostate cancer cell line C4-2 as a model, we studied the effects of PTHrP and the noncalcemic vitamin D analogue EB1089 on markers of prostate cancer cell progression in vitro and in vivo. C4-2 is a second-generation androgen-independent LNCaP subline that metastasizes to the lymph nodes and bone when injected into nude mice and produces mixed lytic/blastic lesions, mimicking the in vivo situation. We report that PTHrP increases cell migration and invasion, and that a pathway via which EB1089 inhibits these processes is through down-regulation of PTHrP expression. PTHrP also increases anchorage-independent cell growth in vitro and xenograft growth in vivo; EB1089 reverses these effects. The in vivo PTHrP effects are accompanied by increased tumor cell proliferation and survival. Treatment with EB1089 reverses the proliferative but not the antiapoptotic effects of PTHrP. PTHrP also increases intratumor vessel density and vascular endothelial growth factor expression; EB1089 reverses these effects. Intracardially injected C4-2 cells produce predominantly osteoblastic lesions; PTHrP overexpression decreases the latency, increases the severity and alters the bone lesion profile to predominantly osteolytic. EB1089 largely reverses these PTHrP effects. A direct correlation between PTHrP immunoreactivity and increasing tumor grade is observed in human prostate cancer specimens. Thus, decreasing PTHrP production by treatment with vitamin D analogues may prove therapeutically beneficial for prostate cancer.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Bone Neoplasms; Calcitriol; Cell Line, Tumor; Cell Movement; Cell Proliferation; Humans; Immunoenzyme Techniques; Male; Mice; Mice, Nude; Parathyroid Hormone-Related Protein; Prostate; Prostatic Neoplasms; Xenograft Model Antitumor Assays

Previous research has shown that the retinoid 9-cis retinoic acid (RA) promotes apoptosis in pancreatic cancer cells. The vitamin D analog EB1089 does not. Furthermore, cotreatment of cells with 9-cis RA and EB1089 abrogates apoptosis. To explain this, we studied the regulation of proteins involved in apoptotic signaling pathways in pancreatic cancer cells.. The pancreatic adenocarcinoma cell line T3M4 was used. Cell proliferation was measured using the SRB protein dye assay. Induction of apoptosis was evaluated using an ELISA assay. Caspase activation was detected using a colorimetric assay based on cleavage of a caspase-associated substrate. Regulation of protein levels and posttranslational events were detected using immunoblotting.. We confirm that EB1089 diminishes apoptosis induced by 9-cis RA in T3M4 cells. We extend the study to show that EB1089 abrogates increases, induced by 9-cis RA, in caspase activation, p27Kip1 protein levels, Bim and Bax protein levels and in Bax/Bcl2 ratio. In addition, the CDKI p21Waf1 and CAII, a differentiation marker for pancreatic cancer cells are also differentially regulated.. These results suggest that the inhibitory effects of EB1089 on 9-cis RA-induced apoptosis lie upstream of caspase activation and could be associated with reduction of p27Kip1 protein levels.

Topics: Adenocarcinoma; Alitretinoin; Antineoplastic Agents; Apoptosis; Calcitriol; Caspases; Cell Division; Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor p27; Enzyme-Linked Immunosorbent Assay; Humans; Pancreatic Neoplasms; Tretinoin

To determine the in vitro and in vivo effects of 1,25-dihydroxyvitamin D3 (calcitriol) and two newer less hypercalcaemic analogues, EB1089 and CB1093 (as the use of calcitriol as a therapeutic agent in humans has been limited by hypercalcaemia) in three rodent models of prostate cancer.. The highly metastatic MAT LyLu Dunning prostate model, PAIII tumours in Lobund-Wistar rats and LNCaP xenografts in nude mice were used. Vitamin D receptor (VDR) expression and binding were assessed in all cell lines. The effects of calcitriol, EB1089 and CB1093 on tumour growth, cell cycle and angiogenesis in vitro, and growth and serum calcium levels in vivo, were assessed.. The growth of prostate adenocarcinoma was inhibited by calcitriol, EB1089 and CB1093 in the Dunning prostate model. Although both analogues increased serum calcium levels, the levels were significantly less than in rats treated with calcitriol. Tumour growth was also inhibited in male athymic nu/nu mice with LNCaP tumour xenografts. PAIII cells failed to express functional VDR and were insensitive to calcitriol and its analogues, either in vitro or in vivo. The analogues of calcitriol did not inhibit angiogenesis in a rat aorta assay.. This is the first report comparing the actions of calcitriol and its analogues in different in vivo models. The results suggest that the newer less hypercalcaemic analogues of calcitriol may offer a novel therapeutic option for treating prostate cancer. VDR-dependent growth inhibition and not the inhibition of angiogenesis is the main mechanism of action of these compounds in vivo.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Blotting, Western; Calcitriol; Calcium Channel Agonists; Drug Screening Assays, Antitumor; Hypercalcemia; Male; Mice; Mice, Nude; Prostatic Neoplasms; Rats; Rats, Wistar; Receptors, Calcitriol

The aim of this study is to determine the effects of 1,25(OH)2D3 and its analogues on tumor growth and body weight, changes in plasma ionized calcium, parathyroid hormone-related protein (PTHrP) production, bone resorption, and the distribution of the 1,25(OH)2D3 receptor (VDR) on tumors in nude mice-bearing the canine adenocarcinoma (CAC-8). Thirty-seven nude mice were implanted subcutaneously with CAC-8. Two weeks after implantation, the mice were divided into 5 groups and injected intraperitoneally 3 times/week for 4 weeks with 5 different substrates. Group I (nontumor-bearing mice) were injected with vehicle. Groups II through V were CAC-8-bearing mice injected with the following: Grp. II, vehicle; Grp. III, analog V; Grp. IV, 1,25(OH)2D3; and Grp. V, EB1089. Our results showed that mice body weight (% change) of CAC-8-bearing mice was significantly lower than those of nontumor-bearing mice (p<0.05). CAC-8-bearing mice treated with analog V maintained their body weight better than CAC-8-bearing mice treated with either vehicle, 1,25(OH)2D3, or EB1089. A reduction of tumor growth was observed in CAC-8-bearing mice treated with 1,25(OH)2D3 and its analogues; however, the reduction was not statistically significant compared to the vehicle-treated CAC-8-bearing mice. All CAC-8-bearing mice increased osteoclastic bone resorption and hypercalcemia. Immunohistochemical staining of CAC-8 with VDR antibody demonstrated a positive reaction in nuclei of tumor cells. In conclusion, CAC-8-bearing mice treated with analog V were more active and maintained their body weight better than other CAC-8-bearing groups. Analog V-treated mice also showed no toxic side effects of hypercalcemia despite an increase in plasmaionized calcium comparable to nontumor-bearing mice. Tumor volumes of CAC-8-bearing mice treated with 1,25(OH)2D3 and its analogues were smaller than vehicle-treated CAC-8-bearing mice. This finding suggested an inhibitory effect on tumor cell growth.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Body Weight; Bone and Bones; Bone Resorption; Calcitriol; Calcium; Dogs; Immunoenzyme Techniques; Immunohistochemistry; Mice; Mice, Nude; Neoplasm Transplantation; Parathyroid Hormone-Related Protein; Peptide Hormones; Radioimmunoassay; Receptors, Calcitriol

The beta-catenin signaling pathway is deregulated in nearly all colon cancers. Nonhypercalcemic vitamin D3 (1alpha,25-dehydroxyvitamin D(3)) analogues are candidate drugs to treat this neoplasia. We show that these compounds promote the differentiation of human colon carcinoma SW480 cells expressing vitamin D receptors (VDRs) (SW480-ADH) but not that of a malignant subline (SW480-R) or metastasic derivative (SW620) cells lacking VDR. 1alpha,25(OH)2D(3) induced the expression of E-cadherin and other adhesion proteins (occludin, Zonula occludens [ZO]-1, ZO-2, vinculin) and promoted the translocation of beta-catenin, plakoglobin, and ZO-1 from the nucleus to the plasma membrane. Ligand-activated VDR competed with T cell transcription factor (TCF)-4 for beta-catenin binding. Accordingly, 1alpha,25(OH)2D(3) repressed beta-catenin-TCF-4 transcriptional activity. Moreover, VDR activity was enhanced by ectopic beta-catenin and reduced by TCF-4. Also, 1alpha,25(OH)2D(3) inhibited expression of beta-catenin-TCF-4-responsive genes, c-myc, peroxisome proliferator-activated receptor delta, Tcf-1, and CD44, whereas it induced expression of ZO-1. Our results show that 1alpha,25(OH)2D(3) induces E-cadherin and modulates beta-catenin-TCF-4 target genes in a manner opposite to that of beta-catenin, promoting the differentiation of colon carcinoma cells.

Topics: Active Transport, Cell Nucleus; Adenocarcinoma; Antineoplastic Agents; beta Catenin; Cadherins; Calcitriol; Cell Adhesion Molecules; Cell Differentiation; Cell Membrane; Cholecalciferol; Colonic Neoplasms; Cytoskeletal Proteins; Gene Expression Regulation, Neoplastic; Humans; Ligands; Macromolecular Substances; Phenotype; Protein Binding; Receptors, Calcitriol; RNA, Messenger; Signal Transduction; TCF Transcription Factors; Trans-Activators; Transcription Factor 7-Like 2 Protein; Transcription Factors; Transfection; Tumor Cells, Cultured; Vitamin D

Vitamin D3 is believed to reduce the risk of colon cancer, and serum levels inversely correlate with colorectal cancer incidence. The active metabolite, 1alpha,25-dihydroxyvitamin D3, has previously been shown to inhibit growth and promote differentiation of colon cancer cells. The vitamin D analogue, EB1089, is currently under clinical trial in a variety of cancers because of its growth-inhibitory effects in vitro and reduced hypercalcemic effects in vivo. The mechanism of growth inhibition by EB1089, however, remained to be determined. In this study we examined the effects of alpha,25-dihydroxyvitamin D3 and EB1089 on five colorectal tumor cell lines (two adenoma and three carcinoma) to determine the mechanism of growth inhibition and to ascertain whether premalignant adenoma cells were responsive to these agents. 1alpha,25-Dihydroxyvitamin D3 and EB1089 induced p53-independent apoptosis in adenoma and carcinoma cell lines in a dose-dependent manner between 10(-10) and 10(-6) M. EB1089, as well as inducing apoptosis, increased the proportion of cells in the G1 phase, particularly in the adenoma cell lines. In two of the three carcinoma cell lines (SW620 and PC/JW), levels of apoptosis induced by EB1089 were similar or greater than those induced by 1alpha,25-dihydroxyvitamin D3. Although the carcinoma cell line HT29 was relatively resistant to apoptosis induced by EB1089 compared with 1alpha,25-dihydroxyvitamin D3, EB1089 markedly inhibited cell yields. These observations offer promise for the clinical use of EB1089. To determine whether the induction of apoptosis by 1alpha,25-dihydroxyvitamin D3 and EB1089 was potentially via a differentiation pathway, alkaline phosphatase activity was measured as a marker of differentiation. Induction of alkaline phosphatase was observed in the floating apoptotic cells as well as in the adherent population. A link between the induction of differentiation and apoptosis by 1alpha,25-dihydroxyvitamin D3 and EB1089 is suggested by the occurrence of apoptosis subsequent to the induction of differentiation. To investigate the molecular pathway to apoptosis induction, members of the Bcl-2 family of proteins were examined (Bcl-2, Bcl-x, Bax, and Bak). Decreased Bcl-2 was observed in some cell lines, particularly in response to EB1089, but was not essential for apoptosis. Levels of the proapoptotic protein Bak, however, were consistently increased in all of the five cell lines in association with apoptosis induced by either age

Topics: Adenocarcinoma; Adenoma; Alkaline Phosphatase; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Blotting, Western; Calcitriol; Cell Adhesion; Cell Differentiation; Colorectal Neoplasms; Dose-Response Relationship, Drug; Enzyme Activation; G1 Phase; Genes, p53; Humans; Membrane Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured

The GER human pancreatic carcinoma cell line possesses receptors for 1,25-dihydroxyvitamin D3. We report that the vitamin D analogue EB 1089 inhibits the growth of these cells in vitro and when grown as tumour xenografts in immunodeficient mice. Tumour-bearing mice were given EB 1089 at a dose of 5 microg kg(-1) body weight i.p. thrice weekly for 4-6 weeks. Tumour growth was significantly inhibited in treated animals compared with controls in the absence of hypercalcaemia. These findings may have therapeutic implications in pancreatic cancer.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Calcitriol; Cell Division; Dose-Response Relationship, Drug; Female; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Pancreatic Neoplasms; Receptors, Calcitriol; Transplantation, Heterologous; Tumor Cells, Cultured

The effects of the novel vitamin D analogue, EB1089 alone, or in combination with the retinoid, 9-cis retinoic acid (9-cis RA) on indices of apoptosis in MCF-7 breast cancer cells have been examined. EB1089 was capable of reducing bcl-2 protein, a suppressor of apoptosis, and increasing p53 protein levels in MCF-7 cell cultures following 96h treatment. In the presence of 9-cis RA, EB1089 acted to further enhance the down-regulation and up-regulation of bcl-2 and p53 respectively. Furthermore, EB1089 induces DNA fragmentation in MCF-7 cells, a key feature of apoptosis, alone and in combination with 9-cis RA in situ. The observation that EB1089 and 9-cis RA act in a cooperative manner to enhance induction of apoptosis in these cells may have therapeutic implications.

Topics: Adenocarcinoma; Apoptosis; Breast Neoplasms; Calcitriol; DNA Damage; DNA, Neoplasm; Drug Synergism; Female; Gene Expression Regulation, Neoplastic; Humans; Neoplasm Proteins; Neoplasms, Hormone-Dependent; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Protein p53