Interferon-γ (IFN-γ) has been used to control cancers in clinical treatment. However, an increasing number of reports have suggested that in some cases effectiveness declines after a long treatment period, the reason being unclear. We have reported previously that long-term IFN-γ treatment induces malignant transformation of healthy lactating bovine mammary epithelial cells (BMECs) in vitro. In this study, we investigated the mechanisms underlying the malignant proliferation of BMECs under IFN-γ treatment. The primary BMECs used in this study were stimulated by IFN-γ (10 ng/mL) for a long term to promote malignancy. We observed that IFN-γ could promote malignant cell proliferation, increase the expression of cyclin D1/cyclin-dependent kinase 4 (CDK4), decrease the expression of p21, and upregulate the expression of cellular-abelsongene (c-Abl) and histone deacetylase 2 (HDAC2). The HDAC2 inhibitor, valproate (VPA) and the c-Abl inhibitor, imatinib, lowered the expression level of cyclin D1/CDK4, and increased the expression level of p21, leading to an inhibitory effect on IFN-γ-induced malignant cell growth. When c-Abl was downregulated, the HDAC2 level was also decreased by promoted proteasome degradation. These data suggest that IFN-γ promotes the growth of malignant BMECs through the c-Abl/HDAC2 signaling pathway. Our findings suggest that long-term application of IFN-γ may be closely associated with the promotion of cell growth and even the carcinogenesis of breast cancer.
Animals ; Carcinogenesis/pathology* ; Cattle ; Cell Cycle Proteins/metabolism* ; Cell Proliferation/drug effects* ; Cell Transformation, Neoplastic/pathology* ; Cells, Cultured ; Epithelial Cells/pathology* ; Female ; Histone Deacetylase 2/metabolism* ; Imatinib Mesylate/pharmacology* ; Interferon-gamma/pharmacology* ; Mammary Glands, Animal/pathology* ; Mammary Neoplasms, Experimental/pathology* ; Proto-Oncogene Proteins c-abl/metabolism* ; Signal Transduction ; Valproic Acid/pharmacology*

OBJECTIVETo analyze the opioid binding protein/cell adhesion molecule-like (OPCML) methylation status at different stages of malignant transformation of human bronchial epithelial (16HBE) cells induced by Glycidyl Methacrylate (GMA) and to explore the effect of OPCML methylation in the process of malignant transformation.

METHODSCells were harvested at different stages (the 10th generation, the 20th generation and the 30th generation). To verify the Methylation chip result of OPCML methylation status in the process of malignant transformation, we detected it by methylation-specific-PCR (MSP); Real-time fluorescence Quantitative PCR (qPCR) were applied to measure the gene expression levels of OPCML at different transformed stage, and compared with the control groups (treated with DMSO).

RESULTSBased on the result of methylation chip, the gene of OPCML methylation occurred in all stages, which was consistent to the result of MSP; qPCR showed that the levels of gene expression decreased in the 20th generation and 30th generation.

CONCLUSIONMethylation status of OPCML gene promoter could be considered as a stable and specific biomarker in the transformation process.

Cell Adhesion Molecules ; metabolism ; Cell Transformation, Neoplastic ; chemically induced ; Cells, Cultured ; DNA Methylation ; Epithelial Cells ; cytology ; drug effects ; Epoxy Compounds ; adverse effects ; GPI-Linked Proteins ; metabolism ; Genes, Tumor Suppressor ; Humans ; Methacrylates ; adverse effects ; Promoter Regions, Genetic

OBJECTIVETo characterize the role of tumor necrosis factor-α (TNF-α) and NF-κB play a role in macrophage-like THP-1 cells promoting coal tar pitch extract (CTPE)-induced tumorigenic transformation of human bronchial epithelial cells (BEAS-2B).

METHODSFrom passage 10, CTPE-induced BEAS-2B cells cocultured with THP-1 cells were treated with NF-κB inhibitor-Pyrrolidine dithiocarbamate (PDTC) every 3 passages and TNF-α antibody every passage. Alterations of cell cycle, karyotype and colony formation in soft agar of BEAS-2B cells at passages 20, indicative of tumorigenicity, were determined, respectively. In addition, mRNA and protein levels of TNF receptor associated factor2 (TRAF2) and Cyclin D1 in BEAS-2B cells were measured with Real Time-PCR and Western blot, respectively.

RESULTSThe percentages of S-phase BEAS-2B cells at passage 20 in PDTC group and TNF-α antibody group were (33.97±2.16)% and (34.29±2.04)% respectively, which were less than that in Co-culture+CTPE group of 20th passage [(44.46±0.83)%], P < 0.05; The number of cells with aneuploidy in 100 cells in 20th passage PDTC group and TNF-α antibody group were 40 and 37, and there were significantly different when comparing to that of 20th passage Co-culture+CTPE group (75); The number of colony formation and the rate of colony formation of BEAS-2B cells in soft agar at passage 20 in PDTC group were (15.17±2.48) and (1.51‰±0.25‰), (13.33±2.58)and (1.33‰±0.26‰) in TNF-α antibody group, which were less that those in 20th passage Co-culture+CTPE group [(172.33±12.09) and (17.23‰±1.20‰)], P < 0.05; at the same time, the mRNA and protein levels of TRAF2 and Cyclin D1 in BEAS-2B cells were decreased after PDTC and TNF-α antibody treatment.

CONCLUSIONTNF-α and NF-κB could play an important role in THP-1 cells promoting coal tar pitch extract-induced tumorigenic transformation of BEAS-2B cells by influencing the expression of TRAF2 and Cyclin D1.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; drug effects ; Coal Tar ; toxicity ; Cyclin D1 ; metabolism ; Epithelial Cells ; cytology ; Humans ; Macrophages ; cytology ; NF-kappa B ; metabolism ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

Human mesenchymal stem cells (MSCs) have emerged as attractive cellular vehicles to deliver therapeutic genes for ex-vivo therapy of diverse diseases; this is, in part, because they have the capability to migrate into tumor or lesion sites. Previously, we showed that MSCs could be utilized to deliver a bacterial cytosine deaminase (CD) suicide gene to brain tumors. Here we assessed whether transduction with a retroviral vector encoding CD gene altered the stem cell property of MSCs. MSCs were transduced at passage 1 and cultivated up to passage 11. We found that proliferation and differentiation potentials, chromosomal stability and surface antigenicity of MSCs were not altered by retroviral transduction. The results indicate that retroviral vectors can be safely utilized for delivery of suicide genes to MSCs for ex-vivo therapy. We also found that a single retroviral transduction was sufficient for sustainable expression up to passage 10. The persistent expression of the transduced gene indicates that transduced MSCs provide a tractable and manageable approach for potential use in allogeneic transplantation.
Adolescent ; Animals ; Cell Death/drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Transformation, Neoplastic/drug effects/pathology ; Child ; Cytosine Deaminase/*genetics/therapeutic use ; Fluorouracil/pharmacology ; Genetic Therapy ; Genomic Instability/drug effects ; Humans ; Karyotype ; Mesenchymal Stromal Cells/*cytology/drug effects/metabolism ; Mice ; Multipotent Stem Cells/cytology/drug effects/metabolism ; Neoplasms/therapy ; Retroviridae/*metabolism ; Time Factors ; *Transduction, Genetic

Basal autophagy plays a critical role in maintaining cellular homeostasis and genomic integrity by degrading aged or malfunctioning organelles and damaged or misfolded proteins. However, autophagy also plays a complicated role in tumorigenesis and treatment responsiveness. It can be tumor-suppressing during the early stages of tumorigenesis (i.e., it is an anti-tumor mechanism), as reduced autophagy is found in tumor cells and may be associated with malignant transformation. In this case, induction of autophagy would seem to be beneficial for cancer prevention. In established tumors, however, autophagy can be tumor-promoting (i.e., it is a pro-tumor mechanism), and cancer cells can use enhanced autophagy to survive under metabolic and therapeutic stress. The pharmacological and/or genetic inhibition of autophagy was recently shown to sensitize cancer cells to the lethal effects of various cancer therapies, including chemotherapy, radiotherapy and targeted therapies, suggesting that suppression of the autophagic pathway may represent a valuable sensitizing strategy for cancer treatments. In contrast, excessive stimulation of autophagy may also provide a therapeutic strategy for treating resistant cancer cells having high apoptotic thresholds. In order for us to develop successful autophagy-modulating strategies against cancer, we need to better understand how the roles of autophagy differ depending on the tumor stage, cell type and/or genetic factors, and we need to determine how specific pathways of autophagy are activated or inhibited by the various anti-cancer therapies.
Anticarcinogenic Agents/therapeutic use ; Autophagy/*physiology ; Cell Transformation, Neoplastic/drug effects ; Humans ; Neoplasms/*drug therapy/metabolism/*pathology

To investigate the effect of monoamine oxidase inhibitor tranylcypromine (TCP) on the differentiation of human U251 glioma cells, we treated U251 cells with TCP and/or 100 nmol/L histone deacetylase inhibitor trychostatin A (TSA). The differentiation of U251 cells was observed with inverted microscopy. The cell proliferation and cell cycle distribution were determined by MTT assay and flow cytometry, respectively. Apoptosis was observed by Hoechst 33258 staining. The levels of differentiation-related genes were assessed by real-time PCR and Western blotting. TCP-induced differentiation was characterized by typical morphological changes, inhibition of cellular proliferation, accumulation of cells in the G1 phase of the cell cycle, decreased expression of the pluripotency transcription factors Oct4 and Sox2, and increased expression of glial fibrillary acid protein (GFAP). The combination of TCP and TSA treatment also triggered an over-expression of GFAP. These findings suggest that TCP may induce differentiation of U251 glioma cells, and the differentiation process may be promoted by histone deacetylase inhibitor TSA.
Brain Neoplasms ; pathology ; Cell Line, Tumor ; Cell Transformation, Neoplastic ; drug effects ; Glioma ; pathology ; Histone Deacetylase Inhibitors ; pharmacology ; Humans ; Hydroxamic Acids ; pharmacology ; Monoamine Oxidase Inhibitors ; pharmacology ; Tranylcypromine ; pharmacology

OBJECTIVETo study the effects of monocyte-macrophages (THP-1) in malignant transformation of human bronchial epithelial cells (BEAS-2B) cells induced by coal tar pitch (CTP) and the expression of TNF-α in the process of the cell malignant transformation.

METHODSBEAS-2B cells and THP-1 Cells were divided into four groups: coal tar pitch (CTP) group, benzo(a)pyrene [B(a)P] group, dimethyl sulfoxide (DMSO) group, BEAS-2B and THP-1 co-culture (co-culture group) group. Carcinogenesis model was established. The soft agar colony formation, chromosome aberrations and cell cycle tests were used to detect the cellular malignant transformation. The ELISA assay was utilized to measure the levels of TNF-α in the supernatant of CTP group and co-culture group.

RESULTSThe chromosome number abnormalities could be observed in early stage of the experiment (the 10th generation cells), which showed the increased ratio of aneuploid to polyploid, and the decreased number of diploid. The colony formation rate of co-culture group (the 20th generation cells) was 17.63‰ ± 0.97‰, which was significantly higher than that (13.94‰ ± 0.84‰) of CTP group and that (12.96‰ ± 1.62‰) of B(a)P group (P < 0.05). The proportion of S phase cells in the co-culture group was 44.49% ± 0.68%, which was significantly higher than that (38.19% ± 1.26%) of CTP group and that (36.41% ± 1.19%) of B(a)P group (P < 0.05). The TNF-α level in the co-culture group was significantly higher than that in CTP group (P = 0.001).

CONCLUSIONMonocyte-Macrophages can accelerate the malignant transformation of BEAS-2B cells induced by CTP and increase the expression level of TNF-α.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; chemically induced ; Coal Tar ; toxicity ; Coculture Techniques ; Epithelial Cells ; cytology ; drug effects ; pathology ; Humans ; Macrophages ; cytology ; Monocytes ; cytology ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUNDZengshengping (ZSP) tablets had inhibitory effects on oral precancerous lesions by reducing the incidence of oral cancer. However, the severe liver toxicity caused by systemic administration of ZSP limits the long-term use of this anti-cancer drug. The purpose of this study was to evaluate the tumor inhibitory effects due to the topical application of extracts from ZSP, a Chinese herbal drug, on 7, 12-dimethlbenz(a)anthracene (DMBA) induced oral tumors in hamsters. The study also investigated the anti-cancer mechanisms of the ZSP extracts on oral carcinogenesis.

METHODSDMBA (0.5%) was applied topically to the buccal pouches of Syrian golden hamsters (6 - 8 weeks old) three times per week for six weeks in order to induce the development of oral tumors. Different fractions of ZSP were either applied topically to the oral tumor lesions or fed orally at varying dosages to animals with oral tumors for 18 weeks. Tumor volume was measured by histopathological examination. Tumor cell proliferation was evaluated by counting BrdU labeled cells and by Western blotting for mitogen-activated protein kinase (MAPK) protein levels. The protein levels of apoptosis marker Caspase-3 and regulator Bcl-2 protein were also measured by Western blotting.

RESULTSTopical application of DMBA to the left pouch of hamsters induced oral tumor formation. Animals treated with DMBA showed a loss in body weight while animals treated with ZSP maintained normal body weights. Both the ZSP n-butanol fraction and water fraction significantly reduced tumor volume by 32.6% (P < 0.01) and 22.9% (P < 0.01) respectively. Topical application of ZSP also markedly decreased the BrdU-positive cell numbers in oral tumor lesions and reduced the expression level of MAPK. In addition, ZSP promoted tumor cell apoptosis by increasing Caspase-3 expression but decreasing Bcl-2 protein production.

CONCLUSIONThe n-butanol and water fractions of ZSP are effective at inhibiting tumor cell proliferation and stimulating apoptosis in oral cancer suggesting that these fractions have chemopreventive effects on DMBA induced oral carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene ; toxicity ; Animals ; Antineoplastic Agents ; therapeutic use ; Cell Transformation, Neoplastic ; drug effects ; Cricetinae ; Drugs, Chinese Herbal ; therapeutic use ; Male ; Mesocricetus ; Mouth Neoplasms ; chemically induced ; drug therapy ; prevention & control

OBJECTIVETo analyze the methylation status of P16 gene at the different stages of malignant transformation of human bronchial epithelial cells (16HBE) induced by glycidyl methacrylate (GMA) and to explore the DNA methylation mechanisms.

METHODSThe cells exposed to GMA were harvested at the end of exposure (early stage), the 10th generation (protophase) and the 30th generation (anaphase), respectively. The methylation status of P16 promotor was detected by Methylation-specific PCR (MSP). The transformed 16HBE cells were compared with the normal 16HBE cells and the cells exposed to DMSO for methylation status.

RESULTSAt the early stage and protophase stage, the non-methylation status in P16 gene promotor of the normal 16HBE cells and the cells exposed to DMSO appeared, the methylation status in P16 gene promotor of the 16HBE cells exposed to GMA was detected to some extension. At the anaphase stage, the methylation status in P16 gene promotor of the 16HBE cells exposed to GMA or DMSO was detected to some extension.

CONCLUSIONMethylation status of P16 gene promoter was specific at the early stage and protophase stage of malignant transforming in 16HBE cells induced by GMA, which can serve as an early sensitive biological indicator for malignant transforming in 16HBE cells induced by GMA.

Bronchi ; cytology ; drug effects ; pathology ; Cell Transformation, Neoplastic ; genetics ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; Epithelial Cells ; drug effects ; pathology ; Epoxy Compounds ; toxicity ; Humans ; Methacrylates ; toxicity ; Promoter Regions, Genetic

OBJECTIVETo explore the pathogenesis of tumors by blocking the normal differentiation process of stem cells.

METHODSBone marrow mesenchymal stem cells (BMSCs) from rats were isolated, cultured and purified by whole bone marrow adherence method. The rat BMSCs were induced to differentiate into adipocytes with dexamethasone, insulin and indomethacin. Blockage of the differentiation process was induced by 3-methylcholanthrene (3-MC).

RESULTSThe differentiation experiment showed that at 30 days after the induction, oil red O staining-positive cells occurred with increased intracytolasmic lipid droplets, characteristic for adipocytes. The differentiation blockage experiment showed that at 30 days after induction, the deposits of oil red O staining-cytoplasmic lipid droplets was significantly reduced, indicating that the blocked cells were adipocytes, but not fully differentiated. Morphological identification showed that cell contact inhibition disappeared, abnormal cell nuclei, increased number of micronucleus aberration and karyotype abnormalities, indicating that malignant transformation of the stem cells occurred after the differentiation blockage.

CONCLUSIONSThe results of this study show a blockage of the differentiation of that stem cells at the intermediate phase, and a tendency of malignant transformation of the stem cells. The results of our study provide new evidence that cancer stem cells may be originated by suppression of stem cell differentiation.

Adipocytes ; cytology ; Animals ; Bone Marrow Cells ; cytology ; drug effects ; Cell Differentiation ; drug effects ; Cell Transformation, Neoplastic ; Cells, Cultured ; Dexamethasone ; pharmacology ; Drug Combinations ; Female ; Indomethacin ; pharmacology ; Insulin ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Methylcholanthrene ; pharmacology ; Rats ; Rats, Wistar