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The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is known to act via VDR (vitamin D receptor), affecting several physiological processes. In addition, PDIA3 (protein disulphide-isomerase A3) has been associated with some of the functions of 1,25-dihydroxyvitamin D3. In the present study we used siRNA-mediated silencing of PDIA3 in osteosarcoma and prostate carcinoma cell lines to examine the role(s) of PDIA3 for 1,25-dihydroxyvitamin D3-dependent responses. PDIA3 silencing affected VDR target genes and significantly altered the 1,25-dihydroxyvitamin D3-dependent induction of CYP24A1, essential for elimination of excess 1,25-dihydroxyvitamin D3. Also, PDIA3 silencing significantly altered migration and proliferation in prostate PC3 cells, independently of 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 increased thermostability of PDIA3 in cellular thermal shift assay, supporting functional interaction between PDIA3 and 1,25-dihydroxyvitamin D3-dependent pathways. In summary, our data link PDIA3 to 1,25-dihydroxyvitamin D3-mediated signalling, underline and extend its role in proliferation and reveal a novel function in maintenance of 1,25-dihydroxyvitamin D3 levels.

It has become clear that lipid rafts functions as signaling hotspots connecting cell surface receptors to intracellular signaling pathways. However, the exact involvement of lipid rafts in receptor tyrosine kinase signaling is still poorly understood. In this study, we have analyzed platelet-derived growth factor (PDGF) receptor beta (PDGFR-beta) signaling in two different cell lines depleted of cholesterol, and as a consequence, disruption of lipid rafts. Cholesterol depletion of BJ-hTERT fibroblasts using methyl-beta-cyclodextrin (M beta CD) did not affect PDGFR-beta activation as measured by its tyrosine phosphorylation. However, we did observe a small reduction in AKT phosphorylation and a more robust decrease of ERK1/2 activation. In contrast, in the osteosarcoma cell line U2OS, we noticed a deficient receptor activation. Interestingly, in U2OS cells, the ERK1/2 pathway was unaffected, but instead AKT and SRC signaling was reduced. These results suggest that cell type specific wiring of signaling pathways can lead to differential sensitivity to cholesterol depletion. Furthermore, M beta CD treatment had a much more pronounced morphological effect on U2OS compared to BJ-hTERT cells. This is consistent with a previous report claiming that cancer cells are more sensitive to cholesterol depletion than normal cells. Our data supports the possibility that cholesterol lowering drugs may impede tumor growth.

It has become clear that lipid rafts functions as signaling hotspots connecting cell surface receptors to intracellular signaling pathways. However, the exact involvement of lipid rafts in receptor tyrosine kinase signaling is still poorly understood. In this study, we have analyzed platelet-derived growth factor (PDGF) receptor beta (PDGFR-beta) signaling in two different cell lines depleted of cholesterol, and as a consequence, disruption of lipid rafts. Cholesterol depletion of BJ-hTERT fibroblasts using methyl-beta-cyclodextrin (M beta CD) did not affect PDGFR-beta activation as measured by its tyrosine phosphorylation. However, we did observe a small reduction in AKT phosphorylation and a more robust decrease of ERK1/2 activation. In contrast, in the osteosarcoma cell line U2OS, we noticed a deficient receptor activation. Interestingly, in U2OS cells, the ERK1/2 pathway was unaffected, but instead AKT and SRC signaling was reduced. These results suggest that cell type specific wiring of signaling pathways can lead to differential sensitivity to cholesterol depletion. Furthermore, M beta CD treatment had a much more pronounced morphological effect on U2OS compared to BJ-hTERT cells. This is consistent with a previous report claiming that cancer cells are more sensitive to cholesterol depletion than normal cells. Our data supports the possibility that cholesterol lowering drugs may impede tumor growth., Correction in: Cellular signalling, vol. 98, article-id 110411.

The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.

It has become clear that lipid rafts functions as signaling hotspots connecting cell surface receptors to intracellular signaling pathways. However, the exact involvement of lipid rafts in receptor tyrosine kinase signaling is still poorly understood. In this study, we have analyzed platelet-derived growth factor (PDGF) receptor beta (PDGFR-beta) signaling in two different cell lines depleted of cholesterol, and as a consequence, disruption of lipid rafts. Cholesterol depletion of BJ-hTERT fibroblasts using methyl-beta-cyclodextrin (M beta CD) did not affect PDGFR-beta activation as measured by its tyrosine phosphorylation. However, we did observe a small reduction in AKT phosphorylation and a more robust decrease of ERK1/2 activation. In contrast, in the osteosarcoma cell line U2OS, we noticed a deficient receptor activation. Interestingly, in U2OS cells, the ERK1/2 pathway was unaffected, but instead AKT and SRC signaling was reduced. These results suggest that cell type specific wiring of signaling pathways can lead to differential sensitivity to cholesterol depletion. Furthermore, M beta CD treatment had a much more pronounced morphological effect on U2OS compared to BJ-hTERT cells. This is consistent with a previous report claiming that cancer cells are more sensitive to cholesterol depletion than normal cells. Our data supports the possibility that cholesterol lowering drugs may impede tumor growth., Correction in: Cellular signalling, vol. 98, article-id 110411.

The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.

The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.

It has become clear that lipid rafts functions as signaling hotspots connecting cell surface receptors to intracellular signaling pathways. However, the exact involvement of lipid rafts in receptor tyrosine kinase signaling is still poorly understood. In this study, we have analyzed platelet-derived growth factor (PDGF) receptor beta (PDGFR-beta) signaling in two different cell lines depleted of cholesterol, and as a consequence, disruption of lipid rafts. Cholesterol depletion of BJ-hTERT fibroblasts using methyl-beta-cyclodextrin (M beta CD) did not affect PDGFR-beta activation as measured by its tyrosine phosphorylation. However, we did observe a small reduction in AKT phosphorylation and a more robust decrease of ERK1/2 activation. In contrast, in the osteosarcoma cell line U2OS, we noticed a deficient receptor activation. Interestingly, in U2OS cells, the ERK1/2 pathway was unaffected, but instead AKT and SRC signaling was reduced. These results suggest that cell type specific wiring of signaling pathways can lead to differential sensitivity to cholesterol depletion. Furthermore, M beta CD treatment had a much more pronounced morphological effect on U2OS compared to BJ-hTERT cells. This is consistent with a previous report claiming that cancer cells are more sensitive to cholesterol depletion than normal cells. Our data supports the possibility that cholesterol lowering drugs may impede tumor growth., Correction in: Cellular signalling, vol. 98, article-id 110411.

It has become clear that lipid rafts functions as signaling hotspots connecting cell surface receptors to intracellular signaling pathways. However, the exact involvement of lipid rafts in receptor tyrosine kinase signaling is still poorly understood. In this study, we have analyzed platelet-derived growth factor (PDGF) receptor beta (PDGFR-beta) signaling in two different cell lines depleted of cholesterol, and as a consequence, disruption of lipid rafts. Cholesterol depletion of BJ-hTERT fibroblasts using methyl-beta-cyclodextrin (M beta CD) did not affect PDGFR-beta activation as measured by its tyrosine phosphorylation. However, we did observe a small reduction in AKT phosphorylation and a more robust decrease of ERK1/2 activation. In contrast, in the osteosarcoma cell line U2OS, we noticed a deficient receptor activation. Interestingly, in U2OS cells, the ERK1/2 pathway was unaffected, but instead AKT and SRC signaling was reduced. These results suggest that cell type specific wiring of signaling pathways can lead to differential sensitivity to cholesterol depletion. Furthermore, M beta CD treatment had a much more pronounced morphological effect on U2OS compared to BJ-hTERT cells. This is consistent with a previous report claiming that cancer cells are more sensitive to cholesterol depletion than normal cells. Our data supports the possibility that cholesterol lowering drugs may impede tumor growth., Correction in: Cellular signalling, vol. 98, article-id 110411.

The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.

The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.