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

OBJECTIVEFanconi anemia (FA) is characterized by bone marrow failure, congenital abnormalities and predisposition to neoplasia. Hypersensitivity of FA cells to the clastogenic effect of mitomycin C (MMC) provides a unique marker for the diagnosis before the beginning of hematological manifestations. The aim of this study was to evaluate the relationship between Single-Cell Gel Electrophoresis (SCGE) and mitomycin C-induced chromosomal breakage in children with FA.

METHODBetween January 2007 and June 2011, 248 children (< 15 years) with hypocytosis were included. Chromosomal breakage was induced by MMC 0 ng/ml, 40 ng/ml, and 80 ng/ml. SCGE was performed at the same time. We analyzed the results of the two methods and compared with each other. The receiver operating characteristic (ROC) curve was used to evaluate the parameters in SCGE.

RESULTSeventeen patients were diagnosed as FA and 231 as non-FA. Chromosomal breakage was found to be significantly higher in FA patients [(32.2 ± 4.8)%] than non-FA [(19.9 ± 3.0)%] and controls[(21.6 ± 4.8)%] when induced by MMC 80 ng/ml. The parameters of SCGE were significantly different between FA patients and non-FA or controls. All the parameters were rectilinearly correlated with MMC (P = 0.000). The most closely correlated parameter was the rate of comet cell (r = 0.848, P = 0.000). The results of ROC curves suggested the comet cell rate (0.999) was more important.

CONCLUSIONSCGE might be used to discriminate between FA and non-FA individuals. The relationship between SCGE and MMC-induced chromosomal breakage was significant. The rate of comet cell was the important parameter.

Adolescent ; Anemia, Aplastic ; diagnosis ; Case-Control Studies ; Child ; Child, Preschool ; Chromosomal Instability ; Chromosome Breakage ; drug effects ; Comet Assay ; methods ; DNA Damage ; Diagnosis, Differential ; Fanconi Anemia ; diagnosis ; genetics ; Female ; Humans ; Infant ; Male ; Mitomycin ; pharmacology ; Mosaicism ; Pancytopenia ; diagnosis ; genetics ; ROC Curve

OBJECTIVETo compare morphological differences of three drug-resistant hepatocellular carcinoma (HCC) cell subclones (Huh-7/ADM, Huh-7/CBP, Huh-7/MMC) and their parental Huh-7 cell line, to analyze differential microRNA (miRNA) expression profiles in these cells and, finally to screen for the abnormal expressed miRNAs in drug-resistant HCC cells.

METHODSCellular morphology was observed by histology and transmission electron microscopy. MiRNA microarray was used to analyze the differential miRNA expression profiles in these cells (Huh-7, Huh-7/ADM, Huh-7/CBP, Huh-7/MMC) followed by real time quantitative PCR validation.

RESULTSThe drug-resistant cells had more intracytoplasmic organelles and were larger in size along with increased cytological pleomorphism than the parental Huh-7 cells. Compared with the parental Huh-7 cells, 32 simultaneously up-regulated and 22 down-regulated miRNAs were found in three drug-resistant cells. Up-regulation of miR-15a, miR-16, miR-27b, miR-30b, miR-146a, miR-146b-5p, miR-181a, miR-181d and miR-194 was verified by RT-qPCR.

CONCLUSIONDrug-resistant HCC cells have abnormal expressed miRNAs, which may be explored to further investigate the association of miRNA expressions with multidrugs resistance in HCC.

Antineoplastic Agents ; pharmacology ; Carboplatin ; pharmacology ; Carcinoma, Hepatocellular ; genetics ; pathology ; ultrastructure ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Gene Expression Profiling ; Humans ; Liver Neoplasms ; genetics ; pathology ; ultrastructure ; MicroRNAs ; genetics ; metabolism ; Mitomycin ; pharmacology ; Oligonucleotide Array Sequence Analysis

OBJECTIVETo study the effect of the sphingosine kinase 1 (SphK1) inhibitor N,N-dimethylsphingosine (DMS) in combination with chemotherapeutic drugs (DDP, 5-Fu, MMC) on the proliferation of gastric cancer cells (SGC7901) in vitro, and to evaluate whether SphK1 inhibitors could be used as synergetic agents in chemotherapy.

METHODSSGC7901 cells were incubated in vitro with DMS (1 micromol/L) and 5-Fu, DDP, MMC at different concentrations in combination or separately for 24 h. The effects on the growth and survival of SGC7901 cells were determined by MTT assay. The inhibition rates were assessed by response surface analysis and the interactive relationships between the combined drugs were evaluated on the basis of positive/negative values of the cross product coefficients in the response surface equation.

RESULTSThe growth inhibition rate of the gastric cancer cells by treatment with DMS (1 micromol/L) was (10.23 +/- 0.74)%. The growth inhibition rates of the gastric cancer cells treated with 5-Fu (1, 5 and 25 microg/ml) for 24 h were (9.95 +/- 3.24)%, (21.04 +/- 2.19)%, and (45.49 +/- 3.60)%, respectively. The growth inhibition rates of the gastric cancer cells treated with DDP (0.5, 2.5 and 12.5 microg/ml) for 24 h were (9.38 +/- 0.79)%, (19.61 +/- 0.90)%, and (29.83 +/- 0.54)%, respectively. The growth inhibition rates of the gastric cancer cells treated with MMC (0.1, 0.5 and 2.5 microg/ml) for 24 h were (15.35 +/- 0.77)%, (24.72 +/- 0.83)%, and (30.68 +/- 0.28)%, respectively. There were significant differences among the inhibition rates caused by different concentrations of the drugs (P < 0.05). When 1 micromol/L DMS was used in combination with 5-Fu (1, 5, and 25 microg/ml) for 24 h, the growth inhibition rates of the cancer cells were (16.76 +/- 0.41)%, (27.28 +/- 0.29)% and (52.56 +/- 3.60)%, respectively. When 1 micromol/L DMS was used in combination with DDP (0.5, 2.5, and 12.5 microg/ml) for 24 h, the growth inhibition rates of the cancer cells were (15.35 +/- 0.86)%, (25.57 +/- 0.27)%, (36.37 +/- 0.51)%, respectively. When 1 micromol/L DMS was used in combination with MMC (0.1, 0.5, and 2.5 microg/ml) for 24 h, the growth inhibition rates of the cancer cells were (21.02 +/- 0.28)%, (32.10 +/- 0.27)%, (36.36 +/- 0.28)%, respectively. There were also significant differences among the growth inhibition rates caused by different concentrations of the drugs alone and in combination groups (P < 0.05).

CONCLUSIONSDMS can suppress the proliferation of SGC7901 cells in vitro, and there are evident synergetic effects when it is used in combination with chemotherapeutic drugs. The results of this study indicate that SphK1 inhibitors may become novel and promising chemotherapeutic sensitizers.

Antibiotics, Antineoplastic ; pharmacology ; Antimetabolites, Antineoplastic ; pharmacology ; Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cisplatin ; pharmacology ; Drug Synergism ; Enzyme Inhibitors ; pharmacology ; Fluorouracil ; pharmacology ; Humans ; Mitomycin ; pharmacology ; Phosphotransferases (Alcohol Group Acceptor) ; antagonists & inhibitors ; Sphingosine ; analogs & derivatives ; pharmacology ; Stomach Neoplasms ; pathology

BACKGROUNDPrevious studies showed that anti MHC-II monoclone antibody (MAb) only had partial inhibiting effect of alloreactive mixed lymphocyte reaction (MLR) in vitro and it was unsteady and non-persistent. The aim of this research was to determine whether radioactive isotope (188)Re marked MHC-II antibody could benefit the allograft acceptance in transplantation as compared to normal MHC-II antibody.

METHODS188Re was incorporated to 2E9/13F (ab')(2) which is against swine MHC class II antigen (MAb-(188)Re). Porcine peripheral blood mononuclear (PBMC) cells were examined for proliferation and cytokine mRNA expression after stimulation with MHC-II MAb or MAb-(188)Re.

RESULTSThe proliferative response of recipient PBMCs in mixed lymphocyte reaction (MLR) to donor alloantigen showed that the stimulation index of MAb-(188)Re group was significantly lower than the MHC-II MAb group and control (P < 0.05). mRNA expression of interleukin 2, interferon Υ and tumor necrosis factor α (type 1 cytokines) was lower in MAb-(188)Re group than the MHC-II MAb group, while interleukin 10 (type 2 cytokines) was higher in MAb-(188)Re group in the first 24 hours.

CONCLUSIONMAb-(188)Re could help the graft acceptance by inhibiting T cell proliferation, lowering the expression of type 1 cytokines and elevating the type 2 cytokines produced by PBMC.

Animals ; Antibodies, Monoclonal ; chemistry ; pharmacology ; Cell Proliferation ; drug effects ; Interleukin-10 ; genetics ; Interleukin-2 ; genetics ; Isoantigens ; immunology ; Leukocytes, Mononuclear ; drug effects ; radiation effects ; Lymphocyte Culture Test, Mixed ; Mitomycin ; pharmacology ; Radioisotopes ; Reverse Transcriptase Polymerase Chain Reaction ; Rhenium ; Swine ; Tumor Necrosis Factor-alpha ; genetics

The defect or block of apoptosis is an important factor involved in the drug resistance of tumor cells. Blm gene plays a great role in DNA damage and repair. This study was aimed to explore the relationship of blm gene expression with cell cycle and apoptosis after Jurkat DNA damage. The apoptosis rate and change of cell cycle were detected by flow cytometry, the expression level of blm mRNA in Jurkat cells was determined by semi-quantitative RT-PCR. The results indicated that after induction with 0.4 g/L of mitomycin C (MMC) for 24 hours the apoptosis rate of Jurkat cells were (11.42±0.013)%, and (66.08±1.60)% Jurkat cells were arrested in G2/M phase. After induction for 48 hours, the apoptosis rate of Jurkat cells declined from (11.42±0.013)% to (8.08±0.27)%, and cell count of Jurkat cells arrested in G2/M phase decreased from (66.08±1.60)% to (33.96±1.05)%. When induced with 0.4 g/L of MMC for 24 hours, the apoptosis rate of fibroblasts and the percentage of fibroblasts in G2/M, G0-G1 and S phase all showed no significant change until 48 hours. The range of apoptosis rate and the change of cell percentage in three phases were significantly different between Jurkat cells and fibroblasts (p<0.01). Expression level of blm mRNA in Jurkat cells was remarkably higher than that in normal fibroblasts (p<0.01), at 48 hours expression level of blm mRNA was remarkably higher than that at 24 hours. The 2 groups showed clear difference of blm mRNA expression after treated by MMC (p<0.01). It is concluded that the blm gene may play a significant role in repair of DNA damage of Jurkat cells after MMC induction. Abnormal expression of blm is correlated to the drug resistance of leukemia cells.
Apoptosis ; Cell Cycle ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; Humans ; Jurkat Cells ; Mitomycin ; pharmacology ; RecQ Helicases ; genetics

BACKGROUNDRapamycin (RAPA) is a relatively new immunosuppressant drug that functions as a serine/threonine kinase inhibitor to prevent rejection in organ transplantation. RAPA blocks activation of T-effector (Teff) cells by inhibiting the response to interleukin-2. Recently, RAPA was also shown to selectively expand the T-regulator (Treg) cell population. To date, no studies have examined the mechanism by which RAPA converts Teff cells to Treg cells.

METHODSPeripheral CD4(+)CD25(-) naive T cells were cultivated with RAPA and B cells as antigen-presenting cells (APCs) in vitro. CD4(+)CD25(-) T cells were harvested after 6 days and analyzed for expression of forkhead box protein 3 (Foxp3) using flow cytometry. CD4(+)CD25(+)CD127(-) subsets as the converted Tregs were isolated from the mixed lymphocyte reactions (MLR) with CD127 negative selection, followed by CD4 and CD25 positive selection using microbeads and magnetic separation column (MSC). Moreover, mRNA was extracted from converted Tregs and C57BL/6 naive CD4(+)CD25(+) T cells and Foxp3 levels were examined by quantitative real-time polymerase chain reaction (rt-PCR). A total of 1 x 10(5) carboxyfluorescein succinimidyl ester (CFSE)-labeled naive CD4(+)CD25(-) T cells/well from C57BL/6 mice were cocultured with DBA/2 or C3H maturation of dendritic cells (mDCs) (0.25 x 10(5)/well) in 96-well round-bottom plates for 6 days. Then 1 x 10(5) or 0.25 x 10(5) converted Treg cells were added to every well as regulatory cells. Cells were harvested after 6 days of culture and analyzed for proliferation of CFSE-labeled naive CD4(+)CD25(-) T cells using flow cytometry. Data were analyzed using CellQuest software.

RESULTSWe found that RAPA can convert peripheral CD4(+)CD25(-) naive T Cells to CD4(+)Foxp3(+) Treg cells using B cells as APCs, and this subtype of Treg can potently suppress Teff proliferation and maintain antigenic specificity.

CONCLUSIONOur findings provide evidence that RAPA induces Treg cell conversion from Teff cells and uncovers an additional mechanism for tolerance induction by RAPA.

Animals ; Antibiotics, Antineoplastic ; pharmacology ; Antigen-Presenting Cells ; drug effects ; immunology ; metabolism ; B-Lymphocytes ; drug effects ; immunology ; metabolism ; CD4-Positive T-Lymphocytes ; drug effects ; immunology ; metabolism ; Cell Proliferation ; drug effects ; Dendritic Cells ; drug effects ; immunology ; metabolism ; Forkhead Transcription Factors ; metabolism ; Interleukin-2 Receptor alpha Subunit ; metabolism ; Interleukin-7 Receptor alpha Subunit ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred DBA ; Mitomycin ; pharmacology ; Polymerase Chain Reaction ; Sirolimus ; pharmacology ; T-Lymphocytes, Regulatory ; drug effects ; immunology ; metabolism

BACKGROUNDThe antitumor role of Ras association domain family 1A (RASSF1A) gene and its potential molecular mechanisms are not well understood. The objective of this study was to observe the antitumor ability of RASSF1A in hepatocellular carcinoma, and study the mechanisms of cell apoptosis induced by RASSF1A.

METHODSAfter stably transfecting a RASSF1A (wild-type or mutant) expression vector into the BEL-7402 hepatocellular carcinoma cell line, RT-PCR and Western blotting was used to detect the RASSF1A expression levels in recombinant cells. The effects of wild-type RASSF1A on cell growth were observed in vitro by analyzing cell proliferation rate, cell colony formation, and in vivo by analyzing tumorigenesis in nude mice. In addition, the effect of RASSF1A gene expression on the chemosensitivity of human hepatocellular carcinoma cells to antitumor drugs was examined by inhibition of cell proliferation and the percentage of apoptotic cells.

RESULTSWild-type RASSF1A, not the mutant, suppressed cell growth in vitro and in vivo. Re-expression of wild-type RASSF1A could enhance the inhibition of cell proliferation and the percentage of apoptotic cells following cell treatment with mitomycin, but had no significant effect when combined with adriamycin, etoposide, 5-fluorouracil and cisplatin treatment.

CONCLUSIONWild-type RASSF1A inhibits cell growth and enhances cell chemosensitivity to mitomycin in hepatocellular carcinoma, suggesting that RASSF1A may serve as a new target for gene therapy in hepatocellular carcinoma patients.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; genetics ; Blotting, Western ; Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Genetic Therapy ; methods ; Humans ; Mitomycin ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Suppressor Proteins ; genetics ; metabolism ; physiology

OBJECTIVETo establish a simple and efficient method for establishing a mouse model of orthotopic superficial bladder cancer.

METHODSC57BL/6 mice were anesthetized with sodium pentobarbital and catheterized with modified IV catheter (24 G). The mice were intravesically pretreated with HCl and then with NaOH, and after washing the bladders with phosphate-buffered saline (PBS), 100 microl (1 x 10(7)) MB49 cells were infused and allowed to incubate in the bladder for 2 h followed intravesical mitomycin C (MMC) administration. The tumor formation rate, survival, gross hematuria, and bladder weight were determined as the outcome variables, and the pathology of the bladders was observed.

RESULTSInstillation of MB49 tumor cells resulted in a tumor formation rates of 100% in all the pretreated groups while 0% in the control group without pretreatment. MMC significantly reduced the bladder weight as compared to PBS.

CONCLUSIONWe have successfully established a stable, reproducible, and reliable orthotopic bladder cancer model in mice.

Animals ; Cell Line, Tumor ; Cell Transformation, Neoplastic ; Disease Models, Animal ; Female ; Mice ; Mice, Inbred C57BL ; Mitomycin ; pharmacology ; Organ Size ; drug effects ; Urinary Bladder ; drug effects ; pathology ; Urinary Bladder Neoplasms ; pathology

OBJECTIVETo investigate survivin mRNA and protein expressions in mitomycin (MMC)-treated hepatoma carcinoma Hepa1-6 cells in vitro.

METHODSHepa1-6 cells were cultured in vitro in the presence of MMC at the concentrations of 1.0, 3.0 and 9.0 microg/ml, respectively, and 1 day and 3 days after the culture, the cell growth inhibition was assessed using MTT assay and the expressions of survivin were detected by RT-PCR and Western blotting.

RESULTSMMC at the concentration of 9.0 microg/ml resulted in significantly greater growth inhibition of the Hepa-6 cells than MMC at 1.0 and 3.0 microg/ml, and at the latter two concentrations, MMC treatment for 3 days did not produce obvious cell growth inhibition. Survivin expressions at both the mRNA and protein levels in Hepa1-6 cells were significantly decreased 1 day after MMC treatment at the 3 concentrations, and after 3-day MMC treatment at 1.0 and 3 microg/ml, survivin expressions increased to exceed the control level, whereas survivin maintained the low expression levels in cells treated with 9 microg/ml MMC for 3 days.

CONCLUSIONSurvivin expression in Hepa1-6 cells increases in response to MMC treatment at low doses, which might be one of the reasons for chemotherapeutic drug resistance.

Carcinoma, Hepatocellular ; metabolism ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Humans ; Inhibitor of Apoptosis Proteins ; Liver Neoplasms ; metabolism ; Microtubule-Associated Proteins ; metabolism ; Mitomycin ; pharmacology ; RNA, Messenger ; metabolism