OBJECTIVE: To study the effect of knocking down fascin on cervical cancer cell proliferation and tumorigenicity in nude mice. METHODS: Cervical cancer CaSki cells were infected with a lentiviral vector carrying fascin siRNA or with a negative control lentivirus, and fascin mRNA and protein expressions in the cells were detected using qRT-PCR and Western blotting. MTT assay was used to determine the proliferation of CaSki cells with fascin knockdown. CaSki cells transfected with fascin siRNA or the control lentiviral vector and non-transfected CaSki cells were inoculated subcutaneously in nude mice, and the volume and weight of the transplanted tumor were measured; Western blotting was used to detect the expressions of proliferating cell nuclear antigen (PCNA), survivin, cyclin dependent kinase 4 (CDK4) and p21 proteins in the tumor xenograft. RESULTS: Infection with the lentiviral vector carrying fascin siRNA, but not the negative control vector, caused significant reductions in the expression levels of fascin mRNA and protein in CaSki cells ( < 0.05). Fascin knockdown resulted in significantly reduced proliferation of CaSki cells ( < 0.05). The nude mice inoculated with CaSki cells with fascin knockdown showed reduced tumor volume and weight, lowered levels of PCNA, survivin and CDK4, and increased expression of p21 protein in the tumor xenograft compared with the control mice. The negative control lentivirus did not affect the proliferation or tumorigenicity of CaSki cells in nude mice or the expression levels of PCNA, survivin, CDK4 or p21 proteins in the xenografts. CONCLUSIONS Knocking down fascin can inhibit the growth and tumorigenicity of cervical cancer cells in nude mice.
Animals ; Apoptosis ; Carrier Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Cyclin-Dependent Kinase 4 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Female ; Gene Knockdown Techniques ; Genetic Vectors ; Humans ; Mice ; Mice, Nude ; Microfilament Proteins ; genetics ; metabolism ; Proliferating Cell Nuclear Antigen ; metabolism ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; Survivin ; metabolism ; Transfection ; Tumor Burden ; Uterine Cervical Neoplasms ; etiology ; pathology

OBJECTIVETo evaluate the effect of Foxo3a gene over-expression on the development of rat ovarian granulosa cells and in prevention of cisplatin-induced ovarian damage in rats.

METHODSRat ovarian granulose cells released mechanically from the ovaries were cultured in vitro and identified with HE staining and immunohistochemical staining for FSHR. A recombinant adenovirus carrying Foxo3a gene was constructed for infecting the granulose cells, and the cell growth and expressions of cyclin D1, p27, Bax, and Bim were detected; the cell apoptosis and cell cycle changes were detected using Hoechst/PI 33342 staining and flow cytometry, respectively. The transfected cells were challenged with cisplatin and the cell apoptosis was detected with flow cytometry.

RESULTSOver 90% of the cultured cells survived and contained more than 95% ovarian granulose cells. Infection of the cells with the recombinant adenovirus resulted in over-expressions of Foxo3a at the mRNA and protein levels at 36 h and 48 h after the infection, respectively. The infected cells showed suppressed proliferation, increased apoptotic rate and cell cycle arrest in G1 phase with increased expressions of Bim, p27, and cyclin D1 but without significant changes in Bax expression. Cisplatin exposure caused a significantly higher apoptosis rate in the infected cells than in the control cells.

CONCLUSIONOver-expression of Foxo3a gene can promote granulose cell apoptosis by increasing Bim expression and cause cell cycle arrest in G1 phase by increasing cyclin D1 and p27 expressions, but can not prevent the toxic effects of cisplatin on ovarian granulosa cells.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Bcl-2-Like Protein 11 ; Cell Cycle Checkpoints ; Cell Proliferation ; Cells, Cultured ; Cisplatin ; adverse effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Female ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression ; Granulosa Cells ; cytology ; drug effects ; Membrane Proteins ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Rats ; Transfection ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo explore the effect of downregulation of Tiam1 by siRNA on the esophageal squamous cell carcinoma (ESCC) EC9706 cells, and provide theoretical basis for gene therapy of ESCC using Tiam1 as a molecular target.

METHODSTiam1 siRNA was transfected into EC9706 cells, and expression changes of Tiam1 mRNA and protein after transfection were detected by quantitative real-time PCR and Western blotting. Cell proliferation was analyzed using CCK-8 kit. Cell cycle and apoptosis of the EC9706 cells were assessed by flow cytometry. Cell cycle-related proteins and cell apoptosis-associated proteins were analyzed by Western blotting.

RESULTSCompared with the untreated group and control siRNA group, the relative expression levels of Tiam1 mRNA (1.00 and 0.11 ± 0.02) were not significantly different (P > 0.05). The relative expression levels of Tiam1 mRNA in the Tiam1 siRNA group at 24, 48 and 72 h after transfection were 0.30 ± 0.04, 0.09 ± 0.01 and 0.09 ± 0.006, respectively, significantly lower than that of the untreated group (P < 0.05 for all). The expression level of Tiam1 protein at 24 h after Tiam1 siRNA transfection in the EC9706 cells was 0.11 ± 0.02, significantly lower than that in the un-treated group (0.44 ± 0.05) and control siRNA group (0.44 ± 0.04, P < 0.05 for all). The percentages of G0/G1 cells in the Tiam1 siRNA group, untreated group and control siRNA group were (54.48 ± 2.14)%, (40.69 ± 1.85)% and (41.78 ± 1.31)%, respectively (P < 0.01). The percentages of S phase cells in the Tiam1 siRNA group, untreated group and control siRNA group were (27.18 ± 1.65)%, (32.32 ± 1.15)% and (30.35 ± 1.09)%, respectively (P < 0.01). The expression levels of cyclin D1 protein in the untreated group, control siRNA group and Tiam1 siRNA group were 0.43 ± 0.02, 0.41 ± 0.01 and 0.11 ± 0.02, respectively (P < 0.05). The expression levels of p27 protein in the untreated group, control siRNA group and Tiam1 siRNA group were 0.10 ± 0.01, 0.09 ± 0.02 and 0.20 ± 0.02, respectively (P < 0.05). The ratios of early apoptotic cells in the untreated group, control siRNA group and Tiam1 siRNA group were (10 ± 0.9)%, (10 ± 0.5)% and (27 ± 0.7)%, respectively (P < 0.01). The expression levels of Mcl-1 protein in EC9706 cells of untreated group, control siRNA group and Tiam1 siRNA group were 0.47 ± 0.12, 0.48 ± 0.13 and 0.16 ± 0.02, respectively (P < 0.05). The expression levels of Bcl-2 protein in EC9706 cells of the untreated group, control siRNA group and Tiam1 siRNA group were 0.49 ± 0.08, 0.50 ± 0.05 and 0.04 ± 0.03, respectively (P < 0.05). The caspase-3 activities in the untreated group, control siRNA group and Tiam1 siRNA group were 2.3 ± 0.09, 2.3 ± 0.10 and 16.0 ± 1.50, respectively; and that of caspase-9 were 2.3 ± 0.08, 2.3 ± 0.11 and 14.5 ± 0.9, respectively (P < 0.05 for all).

CONCLUSIONSTiam1 siRNA can significantly inhibit the proliferation of esophageal cancer EC9706 cells, induce cell cycle arrest and cell apoptosis. These effects are related to the regulation of the expressions of cell cycle-related genes (cyclin D1 and p27) and cell apoptosis-related genes (Mcl-1, Bcl-1, caspase-3 and caspase-9) by Tiam1 siRNA.

Apoptosis ; Carcinoma, Squamous Cell ; genetics ; metabolism ; pathology ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Cycle Checkpoints ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Down-Regulation ; Esophageal Neoplasms ; genetics ; metabolism ; pathology ; Guanine Nucleotide Exchange Factors ; genetics ; metabolism ; Humans ; Myeloid Cell Leukemia Sequence 1 Protein ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; T-Lymphoma Invasion and Metastasis-inducing Protein 1 ; Transfection

OBJECTIVETo verify the existence and significance of calcium/calmodulin dependent serine protein kinase/inhibitors of differentiation 1 (CASK/Id1) pathway in fibroblasts of human keloid.

METHODSImmunofluorescence laser was used to confirm CASK and Id1 protein expression and localization in fibroblasts of the keloid and normal skin. RT-PCR and Western-blot were adopted to analysis the CASK and Id1 expression and differences between keloid and normal skin fibroblasts. The natural combination of CASK and Id1 protein of keloid fibroblasts was tested by immunoprecipitation.

RESULTSCASK and Id1 protein expression were both found in fibroblast cells of keloid and normal skin under normal circumstances. Most of CASK and Id1 were distributed in the cytoplasm and nucleus of fibroblasts. The results of RT-PCR showed that the expression of CASK mRNA in the keloid group was 0.658 +/- 0.024, which was lower than that in the normal control group (1.076 +/- 0.008, t = 11.159, P < 0.05). The expression of Id1 mRNA was 0.497 +/- 0.014, which was higher than that in the normal control group (0.307 +/- 0.017, t = 15.148, P < 0.05). The results of Western-blot showed that the expression level for CASK protein in the keloid group was 0.057 +/- 0.006, which was lower than that in the normal control group (0.168 +/- 0.012, t = 13.524, P < 0.05); the expression of Id1 protein was 0.812 +/- 0.035, which was higher than that in the normal control group (0.368 +/- 0.031, t = 16.356, P < 0.05). The results of immunoprecipitation showed that Id1 could be detected in the CASK precipitate, while CASK also could be detected in the Id1 precipitate. There was a natural binding of CASK and Id1 in keloid fibroblasts.

CONCLUSIONCASK/Id1 signal pathway may be existed and involved in the proliferation of keloid fibroblasts, which is related with the occurrence of keloid.

Cell Proliferation ; genetics ; Cyclin-Dependent Kinase Inhibitor Proteins ; genetics ; metabolism ; Fibroblasts ; metabolism ; Humans ; Inhibitor of Differentiation Protein 1 ; genetics ; metabolism ; Keloid ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Signal Transduction

Histone deacetylases are involved in many biological processes and have roles in regulating cell behaviors such as cell cycle entry, cell proliferation and apoptosis. However, the effect of histone deacetylases on the development of hair cells (HCs) has not been fully elucidated. In this study, we examined the influence of histone deacetylases on the early development of neuromasts in the lateral line of zebrafish. Hair cell development was evaluated by fluorescent immunostaining in the absence or presence of histone deacetylase inhibitors. Our results suggested that pharmacological inhibition of histone deacetylases with inhibitors, including trichostatin A, valproic acid and MS-275, reduced the numbers of both HCs and supporting cells in neuromasts. We also found that the treatment of zebrafish larvae with inhibitors caused accumulation of histone acetylation and suppressed proliferation of neuromast cells. Real-time PCR results showed that the expression of both p21 and p27 mRNA was increased following trichostatin A treatment and the increase in p53 mRNA was modest under the same conditions. However, the expression of p53 mRNA was significantly increased by treatment with a high concentration of trichostatin A. A high concentration of trichostatin A also led to increased cell death in neuromasts as detected in a TUNEL assay. Moreover, the nuclei of most of these pyknotic cells were immunohistochemically positive for cleaved caspase-3. These results suggest that histone deacetylase activity is involved in lateral line development in the zebrafish and might have a role in neuromast formation by altering cell proliferation through the expression of cell cycle regulatory proteins.
Animals ; Apoptosis ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor Proteins/genetics/metabolism ; Histone Deacetylase Inhibitors/*pharmacology ; Histone Deacetylases/*metabolism ; Histones/metabolism ; Larva/growth & development/metabolism ; Lateral Line System/cytology/*growth & development/metabolism ; Mechanoreceptors/drug effects/*metabolism/physiology ; RNA, Messenger/genetics/metabolism ; Zebrafish ; Zebrafish Proteins/*metabolism

Although it has been suggested that kinesin family member 14 (KIF14) has oncogenic potential in various cancers, including hepatocellular carcinoma (HCC), the molecular mechanism of this potential remains unknown. We aimed to elucidate the role of KIF14 in hepatocarcinogenesis by knocking down KIF14 in HCC cells that overexpressed KIF14. After KIF14 knockdown, changes in tumor cell growth, cell cycle and cytokinesis were examined. We also examined cell cycle regulatory molecules and upstream Skp1/Cul1/F-box (SCF) complex molecules. Knockdown of KIF14 resulted in suppression of cell proliferation and failure of cytokinesis, whereas KIF14 overexpression increased cell proliferation. In KIF14-silenced cells, the levels of cyclins E1, D1 and B1 were profoundly decreased compared with control cells. Of the cyclin-dependent kinase inhibitors, the p27Kip1 protein level specifically increased after KIF14 knockdown. The increase in p27Kip1 was not due to elevation of its mRNA level, but was due to inhibition of the proteasome-dependent degradation pathway. To explore the pathway upstream of this event, we measured the levels of SCF complex molecules, including Skp1, Skp2, Cul1, Roc1 and Cks1. The levels of Skp2 and its cofactor Cks1 decreased in the KIF14 knockdown cells where p27Kip1 accumulated. Overexpression of Skp2 in the KIF14 knockdown cells attenuated the failure of cytokinesis. On the basis of these results, we postulate that KIF14 knockdown downregulates the expression of Skp2 and Cks1, which target p27Kip1 for degradation by the 26S proteasome, leading to accumulation of p27Kip1. The downregulation of Skp2 and Cks1 also resulted in cytokinesis failure, which may inhibit tumor growth. To the best of our knowledge, this is the first report that has identified the molecular target and oncogenic effect of KIF14 in HCC.
Carcinoma, Hepatocellular/*metabolism ; Cyclin-Dependent Kinase Inhibitor p27/genetics/*metabolism ; Cyclins/genetics/metabolism ; *Cytokinesis ; Gene Silencing ; Hep G2 Cells ; Humans ; Kinesin/genetics/*metabolism ; Liver Neoplasms/*metabolism ; Oncogene Proteins/genetics/*metabolism ; Proteasome Endopeptidase Complex/metabolism ; RNA, Messenger/genetics/metabolism ; S-Phase Kinase-Associated Proteins/genetics/metabolism ; *Ubiquitination

OBJECTIVETo investigate the mechanisms by which retinoic acid-induced gene G (RIG-G) protein regulates p21 gene expression.

METHODSWestern blot was used to detect the effects of RIG-G protein overexpression on p21 protein expression level in leukemia cell line NB4 cells and the phosphorylation of both c-Jun and JNK in U937 cells. The c-Jun expression plasmid and p21 gene promoter-containing reporter plasmid were co-transfected into 293T cells, to explore the regulatory effect of c-Jun protein on p21 gene expression by luciferase reporter assay.

RESULTSWestern blot showed that the overexpression of RIG-G protein significantly upregulated p21 protein level in the NB4 cells, and the level of p21 protein largely increased along with the induction of endogenous RIG-G protein during the differentiation of NB4 cells treated by all-trans retinoic acid (ATRA). Moreover, the phosphorylation of both c-Jun and JNK decreased in RIG-G-overexpressing U937 cells while total c-Jun and JNK proteins remained unchanged. After using the JNK inhibitor SP600125 to block JNK phosphorylation, the level of c-Jun phosphorylation was still dramatically reduced in the RIG-G-overexpressing U937T-RIG-G cells, compared with the control U937T-pTRE cells. These results indicated that the inhibitory effect of Rig-G protein on c-Jun phosphorylation could not only be through the JNK pathway, but also via some JNK-independent pathways. Luciferase reporter assay showed that when 0.1, 0.5, 1.0 and 2.0 µg c-Jun-expressing plasmids were respectively transfected into 293T cells, compared with the empty vector-transfected group, the relative luciferase activities were (83.0 ± 1.7)%, (73.7 ± 0.7)%, (68.9 ± 0.9)% and (64.1 ± 0.9)%, indicating that the transcriptional activity of p21 gene could be inhibited by c-Jun protein.

CONCLUSIONSRIG-G protein may suppress the phosphorylation of c-Jun protein through different signal pathways, thereby increasing the expression of p21 gene, arresting the cell cycle and inhibiting the cell growth in U937 cells.

Cell Cycle ; Cell Differentiation ; Cell Line ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; GTP-Binding Proteins ; genetics ; metabolism ; Genes, Reporter ; Phosphorylation ; Signal Transduction ; Transfection ; Tretinoin ; metabolism ; Up-Regulation

BACKGROUND/AIMS: 5'-Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that monitors intracellular AMP/adenosine triphosphate (ATP) ratios and is a key regulator of the proliferation and survival of diverse malignant cell types. In the present study, we investigated the effect of activating AMPK by 5-aminoimidazole-4-carboxamide-ribonucleotide (AICAR) in thyroid cancer cells. METHODS: We used FRO thyroid cancer cells harboring the BRAF(V600E) mutation to examine the effect of AICAR on cell proliferation and cell survival. We also evaluated the involvement of mitogen-activated protein kinase (MAPK) pathways in this effect. RESULTS: We found that AICAR treatment promoted AMPK activation and suppressed cell proliferation and survival by inducing p21 accumulation and activating caspase-3. AICAR significantly induced activation of p38 MAPK, and pretreatment with SB203580, a specific inhibitor of the p38 MAPK pathway, partially but significantly rescued cell survival. Furthermore, small interfering RNA targeting AMPK-alpha1 abolished AICAR-induced activation of p38 MAPK, p21 accumulation, and activation of caspase-3. CONCLUSIONS: Our findings demonstrate that AMPK activation using AICAR inhibited cell proliferation and survival by activating p38 MAPK and proapoptotic molecules in FRO thyroid cancer cells. These results suggest that the AMPK and p38 MAPK signaling pathways may be useful therapeutic targets to treat thyroid cancer.
AMP-Activated Protein Kinases/genetics/metabolism ; Aminoimidazole Carboxamide/*analogs & derivatives/pharmacology ; Antineoplastic Agents/*pharmacology ; Caspase 3/metabolism ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Cyclin-Dependent Kinase Inhibitor p21/metabolism ; Dose-Response Relationship, Drug ; Enzyme Activation ; Enzyme Activators/pharmacology ; Humans ; Mutation ; Protein Kinase Inhibitors/pharmacology ; Proto-Oncogene Proteins B-raf/genetics ; RNA Interference ; Ribonucleotides/*pharmacology ; Signal Transduction/*drug effects ; Thyroid Neoplasms/*enzymology/genetics/pathology ; Time Factors ; Transfection ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism

Ataxia telangiectasia mutated (ATM) kinase plays an essential role in the maintenance of genomic stability. ATM-deficient (ATM(-/-)) mice exhibit hematopoietic stem cell (HSC) dysfunction and a high incidence of lymphoma. Gadd45a controls cell cycle arrest, apoptosis and DNA repair, and is involved in the ATM-p53 mediated DNA damage response. However, the role of Gadd45a in regulating the functionality of ATM(-/-) HSCs is unknown. Here we report that Gadd45a deletion did not rescue the defects of T-cells and B-cells development in ATM(-/-) mice. Instead, ATM and Gadd45a double knockout (ATM(-/-) Gadd45a(-/-)) HSCs exhibited an aggravated defect in long-term self-renewal capacity compared to ATM(-/-) HSCs in HSC transplantation experiments. Further experiments revealed that the aggravated defect of ATM(-/-) Gadd45a(-/-) HSCs was due to a reduction of cell proliferation, associated with an accumulation of DNA damage and subsequent activation of DNA damage response including an up-regulation of p53-p21 signaling pathway. Additionally, ATM(-/-) Gadd45a(-/-) mice showed an increased incidence of hematopoietic malignancies, as well as an increased rate of metastasis than ATM(-/-) mice. In conclusion, Gadd45a deletion aggravated the DNA damage accumulation, which subsequently resulted in a further impaired self-renewal capacity and an increased malignant transformation in ATM(-/-) HSCs.
Animals ; Ataxia Telangiectasia Mutated Proteins ; genetics ; B-Lymphocytes ; pathology ; Cell Cycle Proteins ; genetics ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; DNA Damage ; Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells ; metabolism ; pathology ; Leukemia ; genetics ; pathology ; Lymphoma ; genetics ; pathology ; Mice, Knockout ; Neoplasm Metastasis ; Nuclear Proteins ; genetics ; T-Lymphocytes ; pathology ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo screen the differentially expressed genes in human renal clear-cell carcinoma (RCC) cells using suppression subtractive hybridization (SSH), and to explore their biological function and underlying mechanism in RCC cells.

METHODSTotal RNAs were extracted from human renal clear-cell carcinoma cell line RLC-310 and human normal renal cell line HK-2 cells, and SSH technology was used to construct a RCC cell library of differential expression genes and to screen the most differentially expressed genes. RNA interference vector was constructed to silence the expression of the differentially expressed gene SIPL1 in human renal cell lines RLC-310 and GRC-1. Proliferation index was estimated by cell counting, MTT and tumor xenograft assay. Cell cycle analysis was performed using fluorescence activated cell sorting. Drug resistance potential to adriamycin was assessed by MTT.

RESULTSA subtractive cDNA library of highly expressed genes in the RCC cells was constructed and 12 differentially expressed genes were screened from the subtractive library, in which SIPL1 was the most differently expressed gene in the RCC cell line. SIPL1 overexpression in the RCC cells and clinical samples was confirmed by RT-PCR and Western blot analyses. The shRNA expression plasmid targeting to SIPL1 gene was constructed and transfected into RLC-310 and GRC-1 cells, resulting in downregulation of SIPL1. SIPL1 knockdown inhibited the cell proliferation (P < 0.05) and tumorgenesis. The tumor weights formed by RLC-310 cells transfected with SIPL1 shRNA was (0.22 ± 0.07)g and that of negative control vector was (0.85 ± 0.06)g. The tumor weight formed by GRC-1 cells was (0.32 ± 0.07)g and that of control vectors was (1.21 ± 0.11)g (P < 0.05). SIPL1 shRNA-transfected RLC-310 cells showed that more cells were arrested at G0/G1 phase [(71.13 ± 4.58)%] than that in the negative control RLC-310 cells [(53.27 ± 3.34)%, P < 0.05]. The proportion of G0/G1 phase in the SIPL1 shRNA transfected GRC-1 cells was (73.83 ± 3.97)%, significantly higher than that of (59.33 ± 3.03)% in the negative control GRC-1 cells (P < 0.05), and enhanced their sensitivity to adriamycin (P < 0.05). Silence of SIPL1 caused inactivation of AKT signaling and up-regulated expression of P27(Kip1) and P21(Cip1) proteins.

CONCLUSIONSA differentially expressed gene SIPL1 in the renal clear-cell carcinoma is successfully screened using SSH technology. SIPL1 functions as an oncogene in RCC, and may become a novel molecular target for RCC diagnosis and therapy.

Adenocarcinoma ; metabolism ; pathology ; Adult ; Aged ; Animals ; Antibiotics, Antineoplastic ; pharmacology ; Carcinoma, Renal Cell ; metabolism ; pathology ; Carrier Proteins ; genetics ; metabolism ; Cell Cycle ; Cell Line ; Cell Line, Tumor ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; Female ; Humans ; Kidney ; cytology ; Kidney Neoplasms ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Middle Aged ; Neoplasm Transplantation ; Nucleic Acid Hybridization ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Transfection ; Tumor Burden