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

Senescence-associated secretory phenotype (SASP) is often a concomitant result of cell senescence, embodied by the enhanced function of secretion. The SASP factors secreted by senescent cells include cytokines, proteases and chemokines, etc, which can exert great influence on local as well as systemic environment and participate in the process of cell senescence, immunoregulation, angiogenesis, cell proliferation and tumor invasion, etc. Relative to the abundance of SASP models in human cells, the in vitro SASP model derived from mouse cells is scarce at present. Therefore, the study aimed to establish a mouse SASP model to facilitate the research in the field. With this objective, we treated the INK4a-deficient mouse NIH-3T3 cells and the wildtype mouse embryonic fibroblasts (MEF) respectively with mitomycin C (MMC), an anticarcinoma drug which could induce DNA damage. The occurring of cell senescence was evaluated by cell morphology, β-gal staining, integration ratio of EdU and Western blot. Quantitative RT-PCR and ELISA were used to detect the expression and secretion of SASP factors, respectively. The results showed that, 8 days after the treatment of NIH-3T3 cells with MMC (1 μg/mL) for 12 h or 24 h, the cells became enlarged and the ratios of β-gal-positive (blue-stained) cells significantly increased, up to 77.4% and 90.4%, respectively. Meanwhile, the expression of P21 protein increased and the integration ratios of EdU significantly decreased (P < 0.01). Quantitative RT-PCR detection showed that the mRNA levels of several SASP genes, including IL-6, TNF-α, IL-1α and IL-1β increased evidently. ELISA detection further observed an enhanced secretion of IL-6 (P < 0.01). On the contrary, although wildtype MEF could also be induced into senescence by MMC treatment for 12 h or 24 h, embodied by the enlarged cell volume, increased ratios of β-gal-positive cells (up to 71.7% and 80.2%, respectively) and enhanced expression of P21 protein, the secretion of IL-6 displayed no significant change. Our study indicated that, although MMC could induce senescence in both mouse NIH-3T3 cells and wildtype MEF, only senescent NIH-3T3 cells displayed the canonical SASP phenomena. Current study suggested that senescent NIH-3T3 cells might be an appropriate in vitro SASP model of mouse cells.
Animals ; Cell Proliferation ; Cellular Senescence ; drug effects ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cytokines ; genetics ; metabolism ; DNA Damage ; Fibroblasts ; drug effects ; Interleukin-6 ; secretion ; Mice ; Mitomycin ; pharmacology ; NIH 3T3 Cells ; Phenotype

OBJECTIVETo explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest.

METHODSProtein expression levels were assessed by western blot in the human uveal melanoma 92-1 cells after treatment with ionizing radiation. Depletion of p21 was carried out by employing the siRNA technique. Cell cycle distribution was determined by flow cytometry combined with histone H3 phosphorylation at Ser28, an M-phase marker. Senescence was assessed by senescence- associated-β-galactosidase (SA-β-gal) staining combined with Ki67 staining, a cell proliferation marker.

RESULTSAccompanying increased p21, the protein levels of G2/M transition genes declined significantly in 92-1 cells irradiated with 5 Gy of X-rays. Furthermore, these irradiated cells were blocked at the G2 phase followed by cellular senescence. Depletion of p21 rescued radiation-induced G2 arrest as demonstrated by the upregulation of G2/M transition kinases, as well as the high expression of histone H3 phosphorylated at Ser28. Knockdown of p21 resulted in entry into mitosis of irradiated 92-1 cells. However, cells with serious DNA damage failed to undergo cytokinesis, leading to the accumulation of multinucleated cells.

CONCLUSIONOur results indicated that p21 was responsible for the downregulation of G2/M transition regulatory proteins and the bypass of mitosis induced by irradiation. Downregulation of p21 by siRNA resulted in G2-arrested cells entering into mitosis with serious DNA damage. This is the first report on elucidating the role of p21 in the bypass of mitosis.

Cell Cycle Checkpoints ; radiation effects ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; DNA Damage ; Down-Regulation ; Fibroblasts ; metabolism ; radiation effects ; Gene Expression Regulation ; radiation effects ; Humans ; Mitosis ; radiation effects ; RNA Interference ; RNA, Small Interfering ; Radiation, Ionizing ; Up-Regulation

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.
Animals ; Animals, Newborn ; Biomarkers ; metabolism ; Cell Proliferation ; genetics ; Cyclin-Dependent Kinase 2 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p57 ; genetics ; metabolism ; Cyclins ; genetics ; metabolism ; Gene Expression Regulation ; Hippocampus ; cytology ; metabolism ; Ki-67 Antigen ; genetics ; metabolism ; Magnetic Fields ; MicroRNAs ; genetics ; metabolism ; Neural Stem Cells ; cytology ; metabolism ; Primary Cell Culture ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

In this study, one immortalized human normal prostatic epithelial cell line (BPH) and four human prostate cancer cell lines (LNCaP, 22Rv1, PC-3, and DU-145) were treated with Ganoderma Lucidum triterpenoids (GLT) at different doses and for different time periods. Cell viability, apoptosis, and cell cycle were analyzed using flow cytometry and chemical assays. Gene expression and binding to DNA were assessed using real-time PCR and Western blotting. It was found that GLT dose-dependently inhibited prostate cancer cell growth through induction of apoptosis and cell cycle arrest at G1 phase. GLT-induced apoptosis was due to activation of Caspases-9 and -3 and turning on the downstream apoptotic events. GLT-induced cell cycle arrest (mainly G1 arrest) was due to up-regulation of p21 expression at the early time and down-regulation of cyclin-dependent kinase 4 (CDK4) and E2F1 expression at the late time. These findings demonstrate that GLT suppresses prostate cancer cell growth by inducing growth arrest and apoptosis, which might suggest that GLT or Ganoderma Lucidum could be used as a potential therapeutic drug for prostate cancer.
Antineoplastic Agents, Phytogenic ; isolation & purification ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Caspase 9 ; genetics ; metabolism ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cyclin D1 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Dose-Response Relationship, Drug ; E2F1 Transcription Factor ; genetics ; metabolism ; G1 Phase Cell Cycle Checkpoints ; drug effects ; genetics ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Nucleosomes ; drug effects ; metabolism ; pathology ; Plant Extracts ; chemistry ; Prostate ; drug effects ; metabolism ; pathology ; Reishi ; chemistry ; Signal Transduction ; Triterpenes ; isolation & purification ; pharmacology

Senescence is an important obstacle to cancer development. Engaging a senescent response may be an effective way to cure acute myeloid leukemia (AML). The aim of this study was to examine the effect of resveratrol-downregulated phosphorylated liver kinase B1 (pLKB1) on the senescence of acute myeloid leukemia (AML) stem cells. The protein expressions of pLKB1 and Sirtuin 1 (SIRT1), a regulator of pLKB1, were measured in CD34(+)CD38(-) KG1a cells treated with resveratrol (40 μmol/L) or not by Western blotting. Senescence-related factors were examined, including p21 mRNA tested by real-time PCR, cell morphology by senescence-associated β-galactosidase (SA-β-gal) staining, cell proliferation by MTT assay and cell cycle by flow cytometry. Besides, apoptosis was flow cytometrically determined. The results showed that pLKB1 was highly expressed in CD34(+)CD38(-) KG1a cells, and resveratrol, which could downregulate pLKB1 through activation of SIRT1, induced senescence and apoptosis of CD34(+)CD38(-) KG1a cells. It was concluded that resveratrol-downregulated pLKB1 is involved in the senescence of AML stem cells.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cellular Senescence ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Leukemia, Myeloid, Acute ; enzymology ; genetics ; pathology ; Neoplastic Stem Cells ; drug effects ; Phosphorylation ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Sirtuin 1 ; genetics ; metabolism ; Stilbenes ; pharmacology

To study the effect of the combined administration of different doses of Glycyrrhizae Radix et Rhizoma and Atractylodis Macrocephalae Rhizoma on the proliferation of DFMO-treated intestinal epithelial cells (IEC-6) and p53, p21 mRNA and protein expressions, in order to define the molecular basis for the effect of the combined administration of different doses of Glycyrrhizae Radix et Rhizoma and Atractylodis Macrocephalae Rhizoma on the cell proliferation. The effect of the drugs on the cell division rate and cell cycle of IEC-6 cells was detected by FCM. Quantitative Real-time PCR (qRT-PCR) was used to analyze the effect of the drugs on mRNA of p2l and p53 related to IEC-6 proliferation. Western blot was used to analyze the effect of the drugs on p2l and p53 protein expressions of IEC-6 cells. Atractylodis Macrocephalae Rhizoma could increase p53, p21 mRNA and proteins expression in DFMO-treated IEC-6 cells. The combined administration of different ratios of Atractylodis Macrocephalae Rhizoma and Glycyrrhizae Radix et Rhizoma could significantly down-regulate Atractylodis Macrocephalae Rhizoma's effect on p53, p21 mRNA and proteins expression in DFMO-treated IEC-6 cells and promote the proliferation of IEC-6 cells. The combined administration of Atractylodis Macrocephalae Rhizoma and Glycyrrhizae Radix et Rhizoma could down-regulate Atractylodis Macrocephalae Rhizoma's effect on DFMO-treated intestinal epithelial cells (IEC-6).
Animals ; Atractylodes ; chemistry ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Epithelial Cells ; drug effects ; metabolism ; Gene Expression ; drug effects ; Glycyrrhiza ; chemistry ; Intestines ; drug effects ; metabolism ; Rats ; Rhizome ; chemistry ; Tumor Suppressor Protein p53 ; genetics ; metabolism

OBJECTIVETo construct a recombinant adenovirus expression vector containing the anti-oncogene PTEN and to investigate the effects of the PTEN gene on the proliferation of prostate cancer PC-3 cells and the expressions of cyclin D1 and p21 in the PC-3 cells.

METHODSThe PTEN gene was amplified from the rat hippocampus by RT-PCR and cloned into the shuttle plasmid pEN-TR2A. The plasmids were constructed and amplified in 293A cells. Prostate cancer PC-3 cells were cultured in vitro and infected with the adenoviral vector carrying the PTEN gene (Ad-PTEN). The up-regulation of the PTEN protein was measured by indirect immuno-fluorescence assay; the expressions of PTEN, cyclin D1 and p21 in the cells infected with Ad-PTEN and Ad-LacZ were determined by

RESULTSThe Western blot; and the effect of PTEN on the cell proliferation was detected by MTT assay and plate colony formation. recombinant adenoviral vector Ad-PTEN was successfully constructed. Western blot showed a significantly increased expression of the PTEN protein in the PC-3 cells infected with Ad-PTIEN (0.215 +/-0.065) as compared with that in the control ([0.052 +/-0.009], t = 4. 30, P <0.05) and the Ad-LacZ group ( [0. 056 +/- 0.008 ] , t =4.21, P <0.05). The expression of cyclin D1 was significantly lower in the Ad-PTEN-infected PC-3 cells (0. 256 +/- 0. 072) than in the control ( [0. 502 +/- 0. 087 ], t = 3.77, P < 0.05) and the Ad-LacZ group ([0.498 +/-0.081] , t =3.87, P <0.05), while the expression of p21 remarkably higher in the Ad-PTEN-infected PC-3 cells (0.589 +/-0. 076) than in the control ([0. 146 +/-0.026] , t = 9.55, P<0. 01) and the Ad-LacZ group ([0. 163 +/-0. 024] , t = 9.26, P <0.01). Ad-PTEN significantly inhibited the growth of the PC-3 cells (21.98%) at 48 h (t = 6.80, P <0.01). The colony formation rate of the PC-3 cells was (37.4 +/-4. 18)% in the Ad-PTEN group, significantly lower than (54.9 +/-4.81)% in the control (t =4.76, P<0.01) and (56.5 +/- 5.42)% in the Ad-LacZ group (t=4.83, P<0.01).

CONCLUSIONThe expression of PTEN induced by Ad-PTEN can significantly inhibit the proliferation of PC-3 cells, down-regulate the expression of cyclin D1, and up-regulate the expression of p21.

Adenoviridae ; genetics ; Animals ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Humans ; Male ; PTEN Phosphohydrolase ; genetics ; Prostatic Neoplasms ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo assess the effect of small interfering RNA (siRNA)-mediated suppression of CDK6 expression on the proliferation and cell cycles of nasopharyngeal carcinoma (NPC) cells in vitro.

METHODSQRT-PCR was used to examine the differential expression of CDK6 in 30 NPC tissues and 18 normal nasopharyngeal tissues. A siRNA targeting CDK6 was transfected in NPC CNE2 cells, and MTT assay and flow cytometry were used to analyze the changes in cell proliferation and cell cycle distribution. Western blotting was used to examine the expressions of the cell cycle-related factors.

RESULTSCompared with normal nasopharyngeal tissues, NPC tissues showed an increased expression of CDK6 mRNA. Knocking down CDK6 expression obviously inhibited tumor cell growth and cell cycle transition from G1 to S phase and caused reduced expressions of CDK4, CCND1, and E2F1 and enhanced expression of the tumor suppressor p21.

CONCLUSIONNPC tissues overexpress CDK6. Knocking down CDK6 expression inhibits the growth and cell cycle transition of NPC cells in vitro by inhibiting the expressions of CDK4, CCND1, and E2F1 and upregulating tumor suppressor p21 expression.

Carcinoma ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Cyclin-Dependent Kinase 6 ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; E2F1 Transcription Factor ; metabolism ; Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; Humans ; Nasopharyngeal Neoplasms ; pathology ; RNA, Messenger ; RNA, Small Interfering ; Transfection ; 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