Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity

Introduction: Overexpression of the apoptosis-related protein clusterin is associated with breast cancer development and tumor progression. We describe the use of clusterin-specific antisense oligonucleotides and antibodies to sensitize breast carcinoma cells to anticancer drugs routinely used in breast cancer therapy. Methods: MCF-7 and MDA-MB-231 cells were treated with the oligonucleotide or antibody, chemotherapeutic agents (doxorubicin or paclitaxel), tamoxifen, or with combinations of these. Results: Treatments that include antisense clusterin oligonucleotide or antibody to clusterin have been shown to reduce the number of viable cells more effectively than treatment with the drugs alone. We also demonstrate that dexamethasone pretreatment of breast cancer cell lines inhibits chemotherapy-induced cytotoxicity and is associated with the transcriptional induction of clusterin. However, anticlusterin treatment increases chemotherapy-induced cytotoxicity, even in the presence of glucocorticoids, suggesting a possible role for these proteins in glucocorticoid-mediated survival. Conclusion: These data suggest that combined treatment with antibodies to clusterin or antisense clusterin oligodeoxynucleotides and paclitaxel, doxorubicin, or tamoxifen could be a novel and attractive strategy to inhibit the progression of breast carcinoma by regulation of the clusterin function. Moreover, glucocorticoid activation in breast cancer cells regulates survival signaling by the direct transactivation of genes like clusterin which encode proteins that decrease susceptibility to apoptosis. Given the widespread clinical administration of dexamethasone before chemotherapy, understanding glucocorticoid-induced survival mechanisms is essential for achieving optimal therapeutic responses

Evaluación mineral de los componentes del sistema silvopastoril intensivo con Leucaena leucocephala en tres épocas del año

A mineral evaluation of the components of the intensive silvopastoral system, soil, drinking water, forage (Leucaena leucocephala, Megathyrsus maximus) and blood serum of calves and dairy cows was performed. Three samplings were carried out in the cold, dry and rainy seasons. Cu, Fe, Zn, Ca, Mg, K, Na and P were determined and analyzed. Elevated levels of Fe, Ca, K and Mg were found in the soil, while minerals from drinking water remained within adequate ranges, with the exception of Fe (0.61 and 0.57 mg kg-1) at the ranches El Vivero and Los Huarinches, respectively. The concentration of Ca, Mg, K and Na was higher in Leucaena leucocephala than in Megathyrsus maximus, while the content of Cu (6.16 and 5.66 mg kg-1), Zn (17.9 and 24.4) and P (2,584.5 and 2,682.8 mg kg-1) in both ranches do not meet the requirements of the cows, which could generate low levels of these elements in blood serum, in both cows and calves:  Cu (0.64 and 0.54 mg kg-1),  Zn (0.74 and 0.60 mg kg-1) and P (49.24 and 39.43 mg kg-1), respectively.Se realizó evaluación mineral de los componentes del sistema silvopastoril intensivo, suelo, agua de bebida, forraje (Leucaena leucocephala, Megathyrsus máximus) y suero sanguíneo de becerros y vacas lecheras. Se realizaron tres muestreos, en las épocas de frío, secas y lluvias. Se determinaron y analizaron Cu, Fe, Zn, Ca, Mg, K, Na y P. Se encontraron niveles elevados de Fe, Ca, K y Mg en suelo, mientras que los minerales del agua de bebida permanecieron dentro de los rangos adecuados, con excepción del Fe (0.61 y 0.57 mg kg-1) en los ranchos El Vivero y Los Huarinches, respectivamente. La concentración de Ca, Mg, K y Na fue mayor en Leucaena leucocephala que en Megathyrsus máximus, mientras que el contenido de Cu (6.16 y 5.66 mg kg-1), Zn (17.9 y 24.4) y P (2,584.5 y 2,682.8 mg kg-1) en ambos ranchos no satisfacen los requerimientos de las vacas, lo que pudo generar niveles bajos de estos elementos en suero sanguíneo, tanto en las vacas como en las crías: Cu (0.64 y 0.54 mg kg-1), Zn (0.74 y 0.60 mg kg-1) y P (49.24 y 39.43 mg kg-1), respectivamente

Effects of combined treatment with anticlusterin antibody and paclitaxel or doxorubicin on cytotoxicity of the MDA-MB-231 and MCF-7 cell lines

<p><b>Copyright information:</b></p><p>Taken from "Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity"</p><p>http://breast-cancer-research.com/content/9/6/R86</p><p>Breast Cancer Research : BCR 2007;9(6):R86-R86.</p><p>Published online 13 Dec 2007</p><p>PMCID:PMC2246189.</p><p></p> Cells were treated with the antibody for 1 day (30 μg/mL). After antibody treatment, the medium was replaced in some wells with medium containing 10M paclitaxel or doxorubicin for 1 day. Cell viability was determined by trypan blue exclusion test. Each data point represents the mean percentages of at least three independent experiments ± standard error of the mean. **< 0.01. Differences were calculated comparing the combined treatment with anticlusterin antibody or chemotherapeutic agent alone. D, doxorubicin; P, paclitaxel

Effects of antisense clusterin oligonucleotide (ODNclu) on cytotoxicity of breast tumor cell lines

<p><b>Copyright information:</b></p><p>Taken from "Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity"</p><p>http://breast-cancer-research.com/content/9/6/R86</p><p>Breast Cancer Research : BCR 2007;9(6):R86-R86.</p><p>Published online 13 Dec 2007</p><p>PMCID:PMC2246189.</p><p></p> Cells were treated daily with 100 or 500 nM antisense ODNclu or clusterin mismatch control ODN (ODNc) for 2 days. Cell viability was determined by trypan blue exclusion test. Each data point represents the mean percentages of at least three independent experiments ± standard error of the mean. *< 0.05; **< 0.01

Effects of combined treatment with antisense clusterin oligonucleotide (ODNclu) and paclitaxel or doxorubicin on cytotoxicity of the MDA-MB-231 and MCF-7 cell lines

<p><b>Copyright information:</b></p><p>Taken from "Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity"</p><p>http://breast-cancer-research.com/content/9/6/R86</p><p>Breast Cancer Research : BCR 2007;9(6):R86-R86.</p><p>Published online 13 Dec 2007</p><p>PMCID:PMC2246189.</p><p></p> Cells were treated daily with 100 nM antisense ODNclu or clusterin mismatch control ODN (ODNc) for 2 days. After ODN treatment, the medium was replaced with medium containing 10and 10M paclitaxel or doxorubicin. Cell viability was determined by trypan blue exclusion test. Each data point represents the mean percentages of at least three independent experiments ± standard error of the mean. D, doxorubicin; P, paclitaxel. *< 0.05; **< 0.01; ***< 0.001

Reverse transcription-polymerase chain reaction analysis showing a strong decrease in clusterin RNA after treatment with antisense oligodeoxynucleotides to clusterin (ODNclu) in the MDA-MB-231 and MCF-7 cell lines

<p><b>Copyright information:</b></p><p>Taken from "Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity"</p><p>http://breast-cancer-research.com/content/9/6/R86</p><p>Breast Cancer Research : BCR 2007;9(6):R86-R86.</p><p>Published online 13 Dec 2007</p><p>PMCID:PMC2246189.</p><p></p> C, basal expression; MW, molecular weight; ODNc, control oligonucleotide

Effects of combined treatment with antisense clusterin oligonucleotide (ODNclu) (at 100 and 500 nM) and tamoxifen (10M) on cytotoxicity of the MCF-7 cell line

<p><b>Copyright information:</b></p><p>Taken from "Anticlusterin treatment of breast cancer cells increases the sensitivities of chemotherapy and tamoxifen and counteracts the inhibitory action of dexamethasone on chemotherapy-induced cytotoxicity"</p><p>Breast Cancer Research : BCR 2007;9(6):R86-R86.</p><p>Published online 13 Dec 2007</p><p>PMCID:PMC2246189.</p><p></p> The same treatment schedule described in figure 3 was followed. **< 0.01; ***< 0.001. ODNc, control oligonucleotide