The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Shou-li Wang - One of the best experts on this subject based on the ideXlab platform.
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Effects of transforming growth factor beta 1 on the growth of Rhabdomyosarcoma Cell Line RD.
Chinese medical journal, 2005Co-Authors: Hong-ying Zhang, Hua Wang, Guang-hua Yang, Li Zhang, Shou-li WangAbstract:BACKGROUND: Transforming growth factor-beta (TGF-beta) can inhibit the growth of most epithelial and endothelial Cells. The growth regulative role of TGF-beta on soft tissue sarcoma was seldom reported. Here we examined TGF-beta1 effects on the growth of human Rhabdomyosarcoma Cell RD and searched the relative molecular mechanism. METHODS: The viability of RD was examined by [(3)H]-thymidine incorporation and [3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyl tetrazolium bromide] (MTT) assay. RD Cell cycle was analysed by flow cytometry. The protein and mRNA of Cell cycle regulative factors in RD were detected by Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The kinase activity of cdk2 or cdk4 was examined by immunoprecipitation and kinase assay. Immunofluorescent staining was used to detect the location of Cell cycle regulative factors in RD by laser scanning confocal microscope. RESULTS: TGF-beta1 inhibits RD proliferation by G1-arrest in Cell cycle progression. TGF-beta1 can prominently up-regulate P27 of RD, then augment P27 to bind cycLine-cdk2 complexes, which effectively suppress cdk2 kinase activity. P21 increased and c-myc decreased in RD due to TGF-beta1. Both P15 and cdk4 have not been involved in the growth inhibitory event. TGF-beta1 treatment induced P27 to congregate around nucleus. P21 pervaded from nucleus to both nucleus and cytoplasm by TGF-beta1 treatment. CONCLUSION: TGF-beta1 inhibits the proliferation of human Rhabdomyosarcoma Cell Line RD and induces RD G1-arrest. This course is accomplished by TGF-beta1 up-regulating P27 to suppress cdk2 kinase activity. The induction of P21 and down-regulation of C-myc might participate in the growth-arrest event.
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Systematic analysis of the TGF-β/Smad signalling pathway in the Rhabdomyosarcoma Cell Line RD
International journal of experimental pathology, 2003Co-Authors: Hua Wang, Guang-hua Yang, Qiao Zhou, Li-xin Guo, Shou-li WangAbstract:Transforming growth factor-β (TGF-β) is a multifunctional regulator of Cell growth and differentiation, whose actions are highly Cell type specific. To study the role of the TGF-β1 autocrine loop in regulating growth and myogenic differentiation in the human Rhabdomyosarcoma Cell Line, RD, an attempt was made to establish a framework for the expression of several components of TGF-β1/Smad signalling pathway at the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis in RD Cells compared with the normal myoblasts. Higher exogenous concentration of TGF-β1 was necessary to reach a growth-inhibition effect, whereas TGF-β1 downregulated the expression of myosin heavy-chain mRNA at lower concentrations than that was required for growth inhibition. Treatment with TGF-β1 significantly decreased the number of sarcomeric actin and myosin-expressing Cells. In this study, we have shown that RD Cells displayed higher expression of TβRI, TβRII, Smad2 and Smad4 at both the mRNA and protein levels than myoblasts. Smad3 and Smad7 mRNA were expressed at higher level in RD Cells than in myoblasts. The staining patterns of TβR and Smads suggest that they may transduce different TGF-β1 signalling in RD Cells than in myoblasts. TGF-β1 signalling induced a rapid relocation of Smad2 to the nucleus; in contrast, Smad4 remained localized to the cytoplasm unless it was coexpressed with Smad2. These studies suggest that signalling from the Cell surface to the nucleus through Smad proteins is a required component of TGF-β1-induced Cell response in RD Cells. The RD Cell Line is a suitable model to study the TGF-β autocrine loop involved in growth and differentiation of RMS.
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systematic analysis of the tgf β smad signalling pathway in the Rhabdomyosarcoma Cell Line rd
International Journal of Experimental Pathology, 2003Co-Authors: Hua Wang, Guang-hua Yang, Qiao Zhou, Li-xin Guo, Shou-li WangAbstract:Transforming growth factor-β (TGF-β) is a multifunctional regulator of Cell growth and differentiation, whose actions are highly Cell type specific. To study the role of the TGF-β1 autocrine loop in regulating growth and myogenic differentiation in the human Rhabdomyosarcoma Cell Line, RD, an attempt was made to establish a framework for the expression of several components of TGF-β1/Smad signalling pathway at the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis in RD Cells compared with the normal myoblasts. Higher exogenous concentration of TGF-β1 was necessary to reach a growth-inhibition effect, whereas TGF-β1 downregulated the expression of myosin heavy-chain mRNA at lower concentrations than that was required for growth inhibition. Treatment with TGF-β1 significantly decreased the number of sarcomeric actin and myosin-expressing Cells. In this study, we have shown that RD Cells displayed higher expression of TβRI, TβRII, Smad2 and Smad4 at both the mRNA and protein levels than myoblasts. Smad3 and Smad7 mRNA were expressed at higher level in RD Cells than in myoblasts. The staining patterns of TβR and Smads suggest that they may transduce different TGF-β1 signalling in RD Cells than in myoblasts. TGF-β1 signalling induced a rapid relocation of Smad2 to the nucleus; in contrast, Smad4 remained localized to the cytoplasm unless it was coexpressed with Smad2. These studies suggest that signalling from the Cell surface to the nucleus through Smad proteins is a required component of TGF-β1-induced Cell response in RD Cells. The RD Cell Line is a suitable model to study the TGF-β autocrine loop involved in growth and differentiation of RMS.
Antonia Aránega - One of the best experts on this subject based on the ideXlab platform.
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Multidrug resistance phenotype in the RMS-GR human Rhabdomyosarcoma Cell Line obtained after polychemotherapy.
Japanese journal of cancer research : Gann, 1999Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS), the most common soft tissue malignacy in children, is often accompanied by significant morbidity and poor response. Chemotherapy may induce multidrug resistance (MDR) associated with the expression of P-glycoprotein, a drug efflux pump which modifies the sensitivity of tumoral Cells to drugs. To analyze MDR in RMS we used the RMS-GR Cell Line, obtained from an embryonal Rhabdomyosarcoma treated in vivo with polychemotherapy. The RMS-GR Cells showed cross-resistance to vincristine, doxorubicin and actinomycin D, the drugs of choice in the conventional treatment of RMS. Polymerase chain reaction (PCR) analysis showed that these RMS Cells overexpressed mdr1/P-glycoprotein. The pattern of resistance and the level of P-glycoprotein expression were similar to those found in the resistant RMS TE.32.7.DAC Cell Line obtained in vitro. Southern blot analysis showed that mdr1 overexpression was not due to amplification of the gene. Our results showed that the in vivo treatment of embryonal RMS may induce an MDR phenotype mediated by mdr1/P-glycoprotein in RMS Cells.
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Therapeutic differentiation in a human Rhabdomyosarcoma Cell Line selected for resistance to actinomycin D
International journal of cancer, 1998Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS) is accompanied often by significant morbidity and poor response. The use of cytotoxic agents may induce a multidrug resistance phenotype, which plays an important role in the sensitivity of tumoral Cells to drugs. Using actinomycin D, a drug of choice in the treatment of RMS, we induced resistance in the TE.32.7 human RMS Cell Line. The TE.32.7-DAC-resistant Cell Line exhibited cross-resistance to vincristine and doxorubicin and showed mdr1/P-glycoprotein over-expression, suggesting that this mechanism was involved in the reduction in intraCellular drug concentration and may be responsible for the failure of treatment of RMS with classical cycles of cytotoxics. Furthermore, this resistant Cell Line showed increased expression of the muscle differentiation markers desmin and α-actinin and ultrastructural changes which clearly indicated myogenic differentiation. Our findings suggest that, although this tumor is probably arrested along the normal myogenic pathway to maturation, induction of Cell differentiation with anti-neoplastic drugs may be an alternative therapeutic approach. However, the failure of TE.32.7-DAC Cells to completely re-enter the program of myogenic differentiation supports the hypothesis that multidrug resistance is a major obstacle in differentiation therapy for RMS. Int. J. Cancer 75:379–383, 1998. © 1998 Wiley-Liss, Inc.
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Characterization of a new human embryonal Rhabdomyosarcoma Cell Line, RMS-GR.
Japanese journal of cancer research : Gann, 1998Co-Authors: Juan Fernández, Consolación Melguizo, Jose Prados, Luis Alvarez, Nicola Arena, Fabio Malavasi, Antonia AránegaAbstract:A human tumor Cell Line designated RMS-GR was established from an embryonal Rhabdomyosarcoma. The monolayer Cells were polygonal, round or spindle-shaped. The RMS-GR Cell Line became stable with a doubling time of 42 h. Tumorigenicity of the Cells was confirmed by heterotransplantion into nude mice. Electron microscopic images showed typical cytoplasmic inclusion of aggregated intermediate filaments and myofibril-like thin filaments. The expression of desmin, vimentin, actin and human myoglobin was recognized by cytofluorometric analyses, and a large fraction of CK-MM and small fractions of CK-BB and MCK-1 isoenzymes were found. Chromosomal analysis showed that the modal chromosome number was consistently near triploid with structural abnormalities mostly involving chromosomes 1, 3 and 8, and additional unidentified markers. No alteration of chromosome 2 was observed. The RMS-GR Cell Line may provide a system to identify genes which are involved in the pathogenic mechanism of Rhabdomyosarcomas, and to investigate the modulation of myogenic differentiation.
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Inverse expression of mdr 1 and c-myc genes in a Rhabdomyosarcoma Cell Line resistant to actinomycin d.
The Journal of pathology, 1996Co-Authors: Jose Prados, Consolación Melguizo, Antonia Aránega, Luis Alvarez, Alberto Fernández, Antonia AránegaAbstract:Cytotoxic agents used in cancer therapy may induce differentiation in tumour Cells with no proliferative potential. However, chemotherapy can also induce multidrug resistance, a formidable obstacle to the successful treatment of tumours. Both events were recently shown to occur in a Rhabdomyosarcoma Cell Line (RD-DAC) resistant to actinomycin D, a drug of choice in the treatment of these tumours. To analyse this connection, Cell Line RD cultures were investigated with progressive concentrations of actinomycin D and it was shown that a minimum dose (1.2 x 10 -6 mM) of the drug was necessary to increase mdr 1 mRNA in RD-DAC. The mechanism of mdr 1 overexpression was an increase in the number of copies of the mdr 1 gene, although the mRNA levels were not correlated with mdr 1 amplification. Drug resistance mediated by mdr 1 overexpression coincided with the development of myogenic differentiation in RD-DAC and with a decrease in c-myc mRNA levels, whereas levels of N-myc mRNA showed no modulation. These findings suggest that factors implicated in Cell proliferation and differentiation, such as c-myc, may be responsible for the control of genes related to the development of multidrug resistance in Rhabdomyosarcomas. Modulation of these factors may determine the sensitivity of Rhabdomyosarcoma Cells to drugs and may play an important role in triggering the differentiation programme found in these resistant Rhabdomyosarcoma Cells.
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Low sample volume causes differentiation in human Rhabdomyosarcoma Cell Line RD subjected to electroporation.
Cellular and molecular biology (Noisy-le-Grand France), 1996Co-Authors: Antonia Aránega, Consolación Melguizo, Jose Prados, Juan Fernández, Celia Vélez, Antonia Aránega, Juan A. Marchal, N. Arena, Luis AlvarezAbstract:Gene transfection has been accomplished with a variety of techniques such as DEAE dextran, calcium phosphate coprecipitation, protoplast fusion, liposomes, microinjection and recombinant bacteriophages. However, transfection by electroporation, consisting of the reversible permeabilization of Cell membranes after exposure to a pulsed electric field, has been shown to be the most rapid, simple and efficient method for the stable incorporation of genes in different Cell Lines. We studied Rhabdomyosarcoma Cells subjected to electroporation in two different vol. [400 microliters (group 1) and 150 microliters (group 2] of 140 mM NaCl/15 mM Hepes buffer, pH 7.2) and evaluated the effects of electroporation volume on growth and differentiation. Low sample volumes induced a terminal process of morphological and ultrastructural myogenic differentiation in Rhabdomyosarcoma Cells, which concluded with Cell death. Our results suggest that in electroporation low sample vol. of Rhabdomyosarcoma Cells induced morphological and phenotypic differentiation, with increased expression of desmin, alpha-actinin and tropomyosin.
Jose Prados - One of the best experts on this subject based on the ideXlab platform.
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Multidrug resistance phenotype in the RMS-GR human Rhabdomyosarcoma Cell Line obtained after polychemotherapy.
Japanese journal of cancer research : Gann, 1999Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS), the most common soft tissue malignacy in children, is often accompanied by significant morbidity and poor response. Chemotherapy may induce multidrug resistance (MDR) associated with the expression of P-glycoprotein, a drug efflux pump which modifies the sensitivity of tumoral Cells to drugs. To analyze MDR in RMS we used the RMS-GR Cell Line, obtained from an embryonal Rhabdomyosarcoma treated in vivo with polychemotherapy. The RMS-GR Cells showed cross-resistance to vincristine, doxorubicin and actinomycin D, the drugs of choice in the conventional treatment of RMS. Polymerase chain reaction (PCR) analysis showed that these RMS Cells overexpressed mdr1/P-glycoprotein. The pattern of resistance and the level of P-glycoprotein expression were similar to those found in the resistant RMS TE.32.7.DAC Cell Line obtained in vitro. Southern blot analysis showed that mdr1 overexpression was not due to amplification of the gene. Our results showed that the in vivo treatment of embryonal RMS may induce an MDR phenotype mediated by mdr1/P-glycoprotein in RMS Cells.
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Therapeutic differentiation in a human Rhabdomyosarcoma Cell Line selected for resistance to actinomycin D
International journal of cancer, 1998Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS) is accompanied often by significant morbidity and poor response. The use of cytotoxic agents may induce a multidrug resistance phenotype, which plays an important role in the sensitivity of tumoral Cells to drugs. Using actinomycin D, a drug of choice in the treatment of RMS, we induced resistance in the TE.32.7 human RMS Cell Line. The TE.32.7-DAC-resistant Cell Line exhibited cross-resistance to vincristine and doxorubicin and showed mdr1/P-glycoprotein over-expression, suggesting that this mechanism was involved in the reduction in intraCellular drug concentration and may be responsible for the failure of treatment of RMS with classical cycles of cytotoxics. Furthermore, this resistant Cell Line showed increased expression of the muscle differentiation markers desmin and α-actinin and ultrastructural changes which clearly indicated myogenic differentiation. Our findings suggest that, although this tumor is probably arrested along the normal myogenic pathway to maturation, induction of Cell differentiation with anti-neoplastic drugs may be an alternative therapeutic approach. However, the failure of TE.32.7-DAC Cells to completely re-enter the program of myogenic differentiation supports the hypothesis that multidrug resistance is a major obstacle in differentiation therapy for RMS. Int. J. Cancer 75:379–383, 1998. © 1998 Wiley-Liss, Inc.
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Characterization of a new human embryonal Rhabdomyosarcoma Cell Line, RMS-GR.
Japanese journal of cancer research : Gann, 1998Co-Authors: Juan Fernández, Consolación Melguizo, Jose Prados, Luis Alvarez, Nicola Arena, Fabio Malavasi, Antonia AránegaAbstract:A human tumor Cell Line designated RMS-GR was established from an embryonal Rhabdomyosarcoma. The monolayer Cells were polygonal, round or spindle-shaped. The RMS-GR Cell Line became stable with a doubling time of 42 h. Tumorigenicity of the Cells was confirmed by heterotransplantion into nude mice. Electron microscopic images showed typical cytoplasmic inclusion of aggregated intermediate filaments and myofibril-like thin filaments. The expression of desmin, vimentin, actin and human myoglobin was recognized by cytofluorometric analyses, and a large fraction of CK-MM and small fractions of CK-BB and MCK-1 isoenzymes were found. Chromosomal analysis showed that the modal chromosome number was consistently near triploid with structural abnormalities mostly involving chromosomes 1, 3 and 8, and additional unidentified markers. No alteration of chromosome 2 was observed. The RMS-GR Cell Line may provide a system to identify genes which are involved in the pathogenic mechanism of Rhabdomyosarcomas, and to investigate the modulation of myogenic differentiation.
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Low concentrations of actinomycin D potentially cause therapeutic differentiation in human Rhabdomyosarcoma Cell Line RD.
Pathology research and practice, 1996Co-Authors: Consolación Melguizo, Jose Prados, Antonia Aránega, Juan A. Marchal, Luis AlvarezAbstract:Neoplastic transformation may be an alteration in the process of Cell maturation that leads to an infinite capacity for proliferation. Because the cytodestruction caused by most drugs available for cancer chemotherapy is often accompanied by significant morbidity and poor response, the induction of differentiation has been proposed as an alternative approach to conventional anticancer therapy. We used human Rhabdomyosarcoma Cell Line RD to analyze the differentiation process induced by actinomycin D, a drug of choice in the conventional treatment of Rhabdomyosarcomas. Low concentrations of actinomycin D induced a terminal process of morphological and ultrastructural myogenic differentiation in Rhabdomyosarcoma Cells, which concluded with Cell death. However, this potential therapeutic effect cannot be considered complete because of the presence of tumoral Cells that are heterogeneous with respect to actinomycin D chemosensitivity. This heterogeneity led to the appearance of foci of resistant Cells which, despite their greater degree of differentiation in comparison with the parental Cell Line, escaped from terminal myogenic differentiation. This subgroup of tumoral Cells may be responsible for the failure of cytotoxic treatment.
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Inverse expression of mdr 1 and c-myc genes in a Rhabdomyosarcoma Cell Line resistant to actinomycin d.
The Journal of pathology, 1996Co-Authors: Jose Prados, Consolación Melguizo, Antonia Aránega, Luis Alvarez, Alberto Fernández, Antonia AránegaAbstract:Cytotoxic agents used in cancer therapy may induce differentiation in tumour Cells with no proliferative potential. However, chemotherapy can also induce multidrug resistance, a formidable obstacle to the successful treatment of tumours. Both events were recently shown to occur in a Rhabdomyosarcoma Cell Line (RD-DAC) resistant to actinomycin D, a drug of choice in the treatment of these tumours. To analyse this connection, Cell Line RD cultures were investigated with progressive concentrations of actinomycin D and it was shown that a minimum dose (1.2 x 10 -6 mM) of the drug was necessary to increase mdr 1 mRNA in RD-DAC. The mechanism of mdr 1 overexpression was an increase in the number of copies of the mdr 1 gene, although the mRNA levels were not correlated with mdr 1 amplification. Drug resistance mediated by mdr 1 overexpression coincided with the development of myogenic differentiation in RD-DAC and with a decrease in c-myc mRNA levels, whereas levels of N-myc mRNA showed no modulation. These findings suggest that factors implicated in Cell proliferation and differentiation, such as c-myc, may be responsible for the control of genes related to the development of multidrug resistance in Rhabdomyosarcomas. Modulation of these factors may determine the sensitivity of Rhabdomyosarcoma Cells to drugs and may play an important role in triggering the differentiation programme found in these resistant Rhabdomyosarcoma Cells.
Consolación Melguizo - One of the best experts on this subject based on the ideXlab platform.
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Multidrug resistance phenotype in the RMS-GR human Rhabdomyosarcoma Cell Line obtained after polychemotherapy.
Japanese journal of cancer research : Gann, 1999Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS), the most common soft tissue malignacy in children, is often accompanied by significant morbidity and poor response. Chemotherapy may induce multidrug resistance (MDR) associated with the expression of P-glycoprotein, a drug efflux pump which modifies the sensitivity of tumoral Cells to drugs. To analyze MDR in RMS we used the RMS-GR Cell Line, obtained from an embryonal Rhabdomyosarcoma treated in vivo with polychemotherapy. The RMS-GR Cells showed cross-resistance to vincristine, doxorubicin and actinomycin D, the drugs of choice in the conventional treatment of RMS. Polymerase chain reaction (PCR) analysis showed that these RMS Cells overexpressed mdr1/P-glycoprotein. The pattern of resistance and the level of P-glycoprotein expression were similar to those found in the resistant RMS TE.32.7.DAC Cell Line obtained in vitro. Southern blot analysis showed that mdr1 overexpression was not due to amplification of the gene. Our results showed that the in vivo treatment of embryonal RMS may induce an MDR phenotype mediated by mdr1/P-glycoprotein in RMS Cells.
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Therapeutic differentiation in a human Rhabdomyosarcoma Cell Line selected for resistance to actinomycin D
International journal of cancer, 1998Co-Authors: Jose Prados, Consolación Melguizo, Celia Vélez, Juan A. Marchal, Luis Alvarez, Antonia AránegaAbstract:Classical cytotoxic treatment of Rhabdomyosarcoma (RMS) is accompanied often by significant morbidity and poor response. The use of cytotoxic agents may induce a multidrug resistance phenotype, which plays an important role in the sensitivity of tumoral Cells to drugs. Using actinomycin D, a drug of choice in the treatment of RMS, we induced resistance in the TE.32.7 human RMS Cell Line. The TE.32.7-DAC-resistant Cell Line exhibited cross-resistance to vincristine and doxorubicin and showed mdr1/P-glycoprotein over-expression, suggesting that this mechanism was involved in the reduction in intraCellular drug concentration and may be responsible for the failure of treatment of RMS with classical cycles of cytotoxics. Furthermore, this resistant Cell Line showed increased expression of the muscle differentiation markers desmin and α-actinin and ultrastructural changes which clearly indicated myogenic differentiation. Our findings suggest that, although this tumor is probably arrested along the normal myogenic pathway to maturation, induction of Cell differentiation with anti-neoplastic drugs may be an alternative therapeutic approach. However, the failure of TE.32.7-DAC Cells to completely re-enter the program of myogenic differentiation supports the hypothesis that multidrug resistance is a major obstacle in differentiation therapy for RMS. Int. J. Cancer 75:379–383, 1998. © 1998 Wiley-Liss, Inc.
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Characterization of a new human embryonal Rhabdomyosarcoma Cell Line, RMS-GR.
Japanese journal of cancer research : Gann, 1998Co-Authors: Juan Fernández, Consolación Melguizo, Jose Prados, Luis Alvarez, Nicola Arena, Fabio Malavasi, Antonia AránegaAbstract:A human tumor Cell Line designated RMS-GR was established from an embryonal Rhabdomyosarcoma. The monolayer Cells were polygonal, round or spindle-shaped. The RMS-GR Cell Line became stable with a doubling time of 42 h. Tumorigenicity of the Cells was confirmed by heterotransplantion into nude mice. Electron microscopic images showed typical cytoplasmic inclusion of aggregated intermediate filaments and myofibril-like thin filaments. The expression of desmin, vimentin, actin and human myoglobin was recognized by cytofluorometric analyses, and a large fraction of CK-MM and small fractions of CK-BB and MCK-1 isoenzymes were found. Chromosomal analysis showed that the modal chromosome number was consistently near triploid with structural abnormalities mostly involving chromosomes 1, 3 and 8, and additional unidentified markers. No alteration of chromosome 2 was observed. The RMS-GR Cell Line may provide a system to identify genes which are involved in the pathogenic mechanism of Rhabdomyosarcomas, and to investigate the modulation of myogenic differentiation.
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Low concentrations of actinomycin D potentially cause therapeutic differentiation in human Rhabdomyosarcoma Cell Line RD.
Pathology research and practice, 1996Co-Authors: Consolación Melguizo, Jose Prados, Antonia Aránega, Juan A. Marchal, Luis AlvarezAbstract:Neoplastic transformation may be an alteration in the process of Cell maturation that leads to an infinite capacity for proliferation. Because the cytodestruction caused by most drugs available for cancer chemotherapy is often accompanied by significant morbidity and poor response, the induction of differentiation has been proposed as an alternative approach to conventional anticancer therapy. We used human Rhabdomyosarcoma Cell Line RD to analyze the differentiation process induced by actinomycin D, a drug of choice in the conventional treatment of Rhabdomyosarcomas. Low concentrations of actinomycin D induced a terminal process of morphological and ultrastructural myogenic differentiation in Rhabdomyosarcoma Cells, which concluded with Cell death. However, this potential therapeutic effect cannot be considered complete because of the presence of tumoral Cells that are heterogeneous with respect to actinomycin D chemosensitivity. This heterogeneity led to the appearance of foci of resistant Cells which, despite their greater degree of differentiation in comparison with the parental Cell Line, escaped from terminal myogenic differentiation. This subgroup of tumoral Cells may be responsible for the failure of cytotoxic treatment.
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Inverse expression of mdr 1 and c-myc genes in a Rhabdomyosarcoma Cell Line resistant to actinomycin d.
The Journal of pathology, 1996Co-Authors: Jose Prados, Consolación Melguizo, Antonia Aránega, Luis Alvarez, Alberto Fernández, Antonia AránegaAbstract:Cytotoxic agents used in cancer therapy may induce differentiation in tumour Cells with no proliferative potential. However, chemotherapy can also induce multidrug resistance, a formidable obstacle to the successful treatment of tumours. Both events were recently shown to occur in a Rhabdomyosarcoma Cell Line (RD-DAC) resistant to actinomycin D, a drug of choice in the treatment of these tumours. To analyse this connection, Cell Line RD cultures were investigated with progressive concentrations of actinomycin D and it was shown that a minimum dose (1.2 x 10 -6 mM) of the drug was necessary to increase mdr 1 mRNA in RD-DAC. The mechanism of mdr 1 overexpression was an increase in the number of copies of the mdr 1 gene, although the mRNA levels were not correlated with mdr 1 amplification. Drug resistance mediated by mdr 1 overexpression coincided with the development of myogenic differentiation in RD-DAC and with a decrease in c-myc mRNA levels, whereas levels of N-myc mRNA showed no modulation. These findings suggest that factors implicated in Cell proliferation and differentiation, such as c-myc, may be responsible for the control of genes related to the development of multidrug resistance in Rhabdomyosarcomas. Modulation of these factors may determine the sensitivity of Rhabdomyosarcoma Cells to drugs and may play an important role in triggering the differentiation programme found in these resistant Rhabdomyosarcoma Cells.
Hua Wang - One of the best experts on this subject based on the ideXlab platform.
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Effects of transforming growth factor beta 1 on the growth of Rhabdomyosarcoma Cell Line RD.
Chinese medical journal, 2005Co-Authors: Hong-ying Zhang, Hua Wang, Guang-hua Yang, Li Zhang, Shou-li WangAbstract:BACKGROUND: Transforming growth factor-beta (TGF-beta) can inhibit the growth of most epithelial and endothelial Cells. The growth regulative role of TGF-beta on soft tissue sarcoma was seldom reported. Here we examined TGF-beta1 effects on the growth of human Rhabdomyosarcoma Cell RD and searched the relative molecular mechanism. METHODS: The viability of RD was examined by [(3)H]-thymidine incorporation and [3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyl tetrazolium bromide] (MTT) assay. RD Cell cycle was analysed by flow cytometry. The protein and mRNA of Cell cycle regulative factors in RD were detected by Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The kinase activity of cdk2 or cdk4 was examined by immunoprecipitation and kinase assay. Immunofluorescent staining was used to detect the location of Cell cycle regulative factors in RD by laser scanning confocal microscope. RESULTS: TGF-beta1 inhibits RD proliferation by G1-arrest in Cell cycle progression. TGF-beta1 can prominently up-regulate P27 of RD, then augment P27 to bind cycLine-cdk2 complexes, which effectively suppress cdk2 kinase activity. P21 increased and c-myc decreased in RD due to TGF-beta1. Both P15 and cdk4 have not been involved in the growth inhibitory event. TGF-beta1 treatment induced P27 to congregate around nucleus. P21 pervaded from nucleus to both nucleus and cytoplasm by TGF-beta1 treatment. CONCLUSION: TGF-beta1 inhibits the proliferation of human Rhabdomyosarcoma Cell Line RD and induces RD G1-arrest. This course is accomplished by TGF-beta1 up-regulating P27 to suppress cdk2 kinase activity. The induction of P21 and down-regulation of C-myc might participate in the growth-arrest event.
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Systematic analysis of the TGF-β/Smad signalling pathway in the Rhabdomyosarcoma Cell Line RD
International journal of experimental pathology, 2003Co-Authors: Hua Wang, Guang-hua Yang, Qiao Zhou, Li-xin Guo, Shou-li WangAbstract:Transforming growth factor-β (TGF-β) is a multifunctional regulator of Cell growth and differentiation, whose actions are highly Cell type specific. To study the role of the TGF-β1 autocrine loop in regulating growth and myogenic differentiation in the human Rhabdomyosarcoma Cell Line, RD, an attempt was made to establish a framework for the expression of several components of TGF-β1/Smad signalling pathway at the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis in RD Cells compared with the normal myoblasts. Higher exogenous concentration of TGF-β1 was necessary to reach a growth-inhibition effect, whereas TGF-β1 downregulated the expression of myosin heavy-chain mRNA at lower concentrations than that was required for growth inhibition. Treatment with TGF-β1 significantly decreased the number of sarcomeric actin and myosin-expressing Cells. In this study, we have shown that RD Cells displayed higher expression of TβRI, TβRII, Smad2 and Smad4 at both the mRNA and protein levels than myoblasts. Smad3 and Smad7 mRNA were expressed at higher level in RD Cells than in myoblasts. The staining patterns of TβR and Smads suggest that they may transduce different TGF-β1 signalling in RD Cells than in myoblasts. TGF-β1 signalling induced a rapid relocation of Smad2 to the nucleus; in contrast, Smad4 remained localized to the cytoplasm unless it was coexpressed with Smad2. These studies suggest that signalling from the Cell surface to the nucleus through Smad proteins is a required component of TGF-β1-induced Cell response in RD Cells. The RD Cell Line is a suitable model to study the TGF-β autocrine loop involved in growth and differentiation of RMS.
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systematic analysis of the tgf β smad signalling pathway in the Rhabdomyosarcoma Cell Line rd
International Journal of Experimental Pathology, 2003Co-Authors: Hua Wang, Guang-hua Yang, Qiao Zhou, Li-xin Guo, Shou-li WangAbstract:Transforming growth factor-β (TGF-β) is a multifunctional regulator of Cell growth and differentiation, whose actions are highly Cell type specific. To study the role of the TGF-β1 autocrine loop in regulating growth and myogenic differentiation in the human Rhabdomyosarcoma Cell Line, RD, an attempt was made to establish a framework for the expression of several components of TGF-β1/Smad signalling pathway at the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis in RD Cells compared with the normal myoblasts. Higher exogenous concentration of TGF-β1 was necessary to reach a growth-inhibition effect, whereas TGF-β1 downregulated the expression of myosin heavy-chain mRNA at lower concentrations than that was required for growth inhibition. Treatment with TGF-β1 significantly decreased the number of sarcomeric actin and myosin-expressing Cells. In this study, we have shown that RD Cells displayed higher expression of TβRI, TβRII, Smad2 and Smad4 at both the mRNA and protein levels than myoblasts. Smad3 and Smad7 mRNA were expressed at higher level in RD Cells than in myoblasts. The staining patterns of TβR and Smads suggest that they may transduce different TGF-β1 signalling in RD Cells than in myoblasts. TGF-β1 signalling induced a rapid relocation of Smad2 to the nucleus; in contrast, Smad4 remained localized to the cytoplasm unless it was coexpressed with Smad2. These studies suggest that signalling from the Cell surface to the nucleus through Smad proteins is a required component of TGF-β1-induced Cell response in RD Cells. The RD Cell Line is a suitable model to study the TGF-β autocrine loop involved in growth and differentiation of RMS.