Malignant Transformation Of 16HBE Cells Research Articles

DNA methylation and gene expression in malignant transformation of human bronchial epithelial cells induced by glycidyl methacrylate

The aim of this study was to elucidate the role of DNA methylation-silenced genes in malignant transformation. We screened DNA methylation-silenced genes during methacrylate (GMA)-induced malignant transformation of human bronchial epithelial cells (16HBE) by DNA methylation microarray analysis. The methylation status of some identified genes was assessed by a polymerase chain reaction and compared with uninduced control cells. A total of 801, 66 and 30 genes were silenced in 10th, 20th and 30th generation cells; 8 genes were silenced in 10th and 20th generation cells but not in 30th generation cells; 14 genes were silenced in 30th and 10th generation cells but not in 20th generation cells; and one gene was silenced in 20th and 30th generation cells but not in 10th generation cells. TRPV1 and SOD2 genes were methylated and their gene expression levels were significantly lower in 30th generation 16HBE cells treated with GMA compared to uninduced control cells (P < 0.05). The expression levels of DNA methylation-silenced genes were altered throughout the GMA-induced malignant transformation of 16HBE cells. Furthermore, TRPV1/SOD2 may represent a specific molecular marker associated with the malignant transformation of GMA-stimulated 16HBE cells.

Strategies for understanding the role of cellular heterogeneity in the pathogenesis of lung cancer: a cell model for chronic exposure to cigarette smoke extract

BackgroundHuman tumors are highly heterogeneous at the cellular, molecular, genetic and functional levels. Tumor heterogeneity has tremendous impact on cancer progression and treatment responses. However, the mechanisms for tumor heterogeneity have been poorly understood due to the lack of experimental models.MethodsThis study provides a novel exploration and analysis of the impacts of cellular and molecular heterogeneity of human lung epithelial cells on their malignant transformation following chronic exposure to cigarette smoke extracts.ResultsThe ability of cigarette smoke extract (CSE) to cause malignant transformation of the human bronchial epithelial cells (16HBE) is dependent on the sizes of the cells. Epithelial-mesenchymal transition (EMT) plays an important role in this process. Mechanistically, CSE-induced malignant transformation of 16HBE cells was closely linked to the reduced relative telomere length of the larger 16HBE cells, thereby up-regulation of the expression of stemness genes.ConclusionsThese findings provide novel insights for understanding the impact of cellular heterogeneity in lung cancer development. The in vitro transformation model described in this study could be extrapolated to studying the pathogenesis of other malignancies, as well as for mechanistic studies that are not feasible in vivo.

LncRNA SNHG11 promotes the malignant transformation of human bronchial epithelial cells induced by beryllium sulfate.

Beryllium and its compounds are carcinogenicity, but the mechanisms through which this occurs have yet to be clarified. Accumulating evidence exists that long noncoding RNAs (lncRNAs) play an important role in occurrence and development of cancer. To explore the carcinogenic mechanism of beryllium, human bronchial epithelial cells (16HBE) were treated with 50 μM beryllium sulfate (BeSO4) for 45 passages (~23weeks). The expression levels of lncRNA SNHG7, SNHG11, SNHG15, MIR22HG, GMPS, and SIK1 were detected at passage 0 (P0), 15 (P15), 25 (P25), 35 (P35), and 45 (P45). The results indicated that enhanced cell proliferation, extensive clones in soft agar, protein expressions of up-regulated matrix metalloproteinase 9 (MMP9), matrix metalloproteinase 2 (MMP2), proliferating cell nuclear antigen (PCNA), cyclin D1, and down-regulated p53 were all observed at the 45th passage in 16HBE cells. Thus, BeSO4-transformed 16HBE cells (T-16HBE) were established. Meanwhile, the study found that the expression of lncRNA SNHG11 was elevated during malignant transformation. Knockdown of SNHG11 in T-16HBE cells blocked cell proliferation, invasion, and migration, and decreased the protein levels of MMP9, MMP2, PCNA, cyclin D1, but increased p53. The studies revealed that SNHG11 acts as an oncogene in the malignant transformation of 16HBE cells induced by BeSO4, which signifies progress in the study of the carcinogenic mechanism of beryllium.

Role of LncRNA CASC11 in the malignant transformation of 16HBE cells induced by glycidyl methacrylate

To investigate the effect of trending up-regulation LncRNA CASC11 which is differentially expressed during the malignant transformation of human bronchial epithelial cells(16 HBE) induced by glycidyl methacrylate(GMA). After 16 HBE cells were repeatedly exposed to low concentration GMA(8 μg/mL), the 10 th, 20 th and 30 th passage cells of the GMA group and the DMSO solvent control group were collected. High throughput LncRNA microarray were used to screen the differentially expressed LncRNAs at different stages. Short Time-series Expression Miner and bioinformatics tool RPISeq were used to screen and predict the potential targets of specific LncRNA. Real-time fluorescent quantitative PCR(qPCR) and Western blot were used to detect the relative expression of specific LncRNA and the content of its target protein respectively. The specific differential expression of LncRNA CASC11 in the process of GMA-induced malignant transformation of 16 HBE cells showed a trend of up-regulation. Compared with the control cells in the same period, the P10, P20 and P30 generation cells were down-regulated by 1.64 times, up-regulated by 2.01 times, and up-regulated by 2.66 times, respectively. Western blot showed that the levels of cyclin-dependent kinase 1(CDK1), cyclinB1 and cyclinB2 in P10, P20 and P30 cells after exposure were lower than those in DMSO control group during the same period, which was consistent with the microarray results. The differential expression of LncRNA CASC11 in the process of GMA-induced 16 HBE cell malignant transformation was up-regulated trendingly. It is speculated that it may block or delay cell cycle progression by inhibiting CDK1.

Involvement of a novel regulatory cascade consisting of SET-H3K18ac/H3K27ac-53BP1 in Cr(VI)-induced malignant transformation of 16HBE cells

Hexavalent chromium (Cr(VI)) is a well-established human carcinogen with DNA damaging effects. Recently we established a Cr(VI)-induced malignant transformation model from a human bronchial epithelial (16HBE) cell line, and in the transformed (16HBE-T) cells reduced levels of 53BP1 (critical for DNA repair) and the acetylated histone H3K18/27 (H3K18/27ac) were observed. In 16HBE-T cells SET (a multifunctional protein) was elevated by Cr(VI) through quantitative proteomics analysis. In the present study, we further explore the involvement of SET in the H3K18/27ac/53BP1 cascade in the 16HBE-T model, primarily by knockdown of SET. Bioinformatic analysis of the differentially expressed proteins indicated enrichment in histone modifications, in which SET was a major regulator. In 16HBE cells SET expression was enhanced by Cr(VI) in a concentration- and exposure duration-dependent manner. In 16HBE-T cells, SET knockdown showed the following effects: reversal of H3K18/27ac and 53BP1 levels, enhanced enrichment H3K18/27ac in 53BP1′s promotor region, increase rate of apoptosis and cell cycle G0/G1 arrest (with or without Cr(VI) treatment), and reduced colony-forming efficiency. Finally, In comparison with benzo(a)pyrene-transformed (malignant, 16HBE-B) cells from 16HBE where no changes in H3K18/27ac, 53BP1 or SET were observed, while the H3K18/27ac/53BP1 cascade was downregulated and SET upregulated in 16HBE-T cells, as compared with the parental 16HBE cells; thus the changes in 16HBE-T might be a specific effect of Cr(VI). In conclusion, our results suggest that SET may be involved in the malignant cell transformation, through inhibiting the H3K18/27ac/53BP1 cascade, at least in the 16HBE cell model.

The expression of LINC00052 during glycidyl methacrylate-induced malignant transformation of 16HBE cells

Objective: To investigate the expression and role of LINC00052 during glycidyl methacrylate (GMA) -induced malignant transformation of 16HBE cells. Methods: Human bronchial epithelial (16HBE) cells were divided into GMA transformation group and corresponding DMSO control group, and the 10th, 20th and 30th generation cells of each group were collected LncRNA microarrays were used to analysis expression of LINC00052 in different stage of malignant transformation. Bioinformatics analysis was applied and the relative expression of LINC00052 and its potentially target genes was detected by real-time quantification PCR (qPCR) . Results: The results of microarray analysis showed that LINC00052 was up-regulated by 1.32-fold, down-regulated by 1.64-fold and down-regulated by 4.92-fold in the malignant transformation early (P10) , middle term (P20) and late (P30) , respectively, The results of qPCR showed that compared with the DMSO control group, the expression of LINC00052 was up-regulated by 1.55 times, down-regulated by 1.20 times and down-regulated by 2.35 times in P10, P20 and P30, respectively, and the difference was statistically significant (P<0.05) . There was a statistically significant difference in the relative expression of NTRK3 between the GMA transformation group of P10 and P30 generations with the corresponding DMSO control group (P<0.05) . Conclusion: LINC00052 is highly expressed in early time of GMA-induced malignant transformation of 16HBE, and down-regulated in the middle and last stage of malignant transformation and may play a protective role in GMA-induced malignant transformation of 16HBE by influencing the expression of its target gene NTRK3.

Inhibition of the Hedgehog Signaling Pathway Depresses the Cigarette Smoke-Induced Malignant Transformation of 16HBE Cells on a Microfluidic Chip.

Background:The hedgehog signaling system (HHS) plays an important role in the regulation of cell proliferation and differentiation during the embryonic phases. However, little is known about the involvement of HHS in the malignant transformation of cells. This study aimed to detect the role of HHS in the malignant transformation of human bronchial epithelial (16HBE) cells.Methods:In this study, two microfluidic chips were designed to investigate cigarette smoke extract (CSE)-induced malignant transformation of cells. Chip A contained a concentration gradient generator, while chip B had four cell chambers with a central channel. The 16HBE cells cultured in chip A were used to determine the optimal concentration of CSE for inducing malignant transformation. The 16HBE cells in chip B were cultured with 12.25% CSE (Group A), 12.25% CSE + 5 μmol/L cyclopamine (Group B), or normal complete medium as control for 8 months (Group C), to establish the in vitro lung inflammatory-cancer transformation model. The transformed cells were inoculated into 20 nude mice as cells alone (Group 1) or cells with cyclopamine (Group 2) for tumorigenesis testing. Expression of HHS proteins was detected by Western blot. Data were expressed as mean ± standard deviation. The t-test was used for paired samples, and the difference among groups was analyzed using a one-way analysis of variance.Results:The optimal concentration of CSE was 12.25%. Expression of HHS proteins increased during the process of malignant transformation (Group B vs. Group A, F = 7.65, P < 0.05). After CSE exposure for 8 months, there were significant changes in cellular morphology, which allowed the transformed cells to grow into tumors in 40 days after being inoculated into nude mice. Cyclopamine could effectively depress the expression of HHS proteins (Group C vs. Group B, F = 6.47, P < 0.05) and prevent tumor growth in nude mice (Group 2 vs. Group 1, t = 31.59, P < 0.01).Conclusions:The activity of HHS is upregulated during the CSE-induced malignant transformation of 16HBE cells. Cyclopamine can effectively depress expression of HHS proteins in vitro and prevent tumor growth of the transformed cells in vivo.

In vitro malignant transformation of human bronchial epithelial cells induced by benzo(a)pyrene

In this study, the human bronchial epithelial cells (16HBE) were treated five times with 10μM benzo(a)pyrene (BaP), followed by 20 passages culture, and the in vitro BaP-induced malignant transformation of 16HBE cells was established. Five colonies in soft agarose were then amplified and donated as T-16HBE-C1∼5 cells, respectively. T-16HBE-C1∼5 cells can form tumors subcutaneously in nude mice. Histopathological changes in the tumors indicated nests growth, high nuclear-cytoplasmic ratios, coarse and clumped chromatin, numerous and distinctly atypical mitoses, cell necrosis and surrounding normal adipose, muscle and connective tissue immersed. In addition, lung metastasis was observed in nude mice in T-16HBE-C1, 3 and 4 groups. In vitro cell migration assay results indicated that T-16HBE-C2∼5 cells showed much lower migration capabilities than 16HBE cells. Western blotting analysis showed that the expressions of p53 and p-Akt (Ser473) in T-16HBE-C1∼5 cells were significant higher than those in 16HBE cells. Our results demonstrated that BaP could induce the malignant transformation of 16HBE cells, and p53 and p-Akt (Ser473) might play crucial roles in BaP-induced carcinogenesis. The five monoclonal cell lines (T-16HBE-C1∼5) with different migration capabilities could be used as research models for further understanding the mechanisms of BaP-induced carcinogenesis and cell migration.

Alterative Expression and Sequence of Human Elongation Factor-1δ during Malignant Transformation of Human Bronchial Epithelial Cells Induced by Cadmium Chloride

To study the alternative expression and sequence of human elongation factor-1 delta (human EF-1 delta p31) during malignant transformation of human bronchial epithelial cells induced by cadmium chloride (CdC12) and its possible mechanism. Total RNA was isolated at different stages of transformed human bronchial epithelial cells (16HBE) induced by CdCl2 at a concentration of 5.0 microM. Special primers and probe for human EF-1 delta p31 were designed and expression of human EF-1 delta mRNA from different cell lines was detected with fluorescent quantitative PCR technique. EF-18 cDNA from different cell lines was purified and cloned into pMD 18-T vector followed by confirming and sequencing analysis. The expressions of human EF-1 beta p31 at different stages of 16HBE cells transformed by CdCl2 was elevated (P < 0.01 or P < 0.05). Compared with their corresponding non-transformed cells, the overexpression level of EF-1 delta p31 was averagely increased 2.9 folds in Cd-pretransformed cells, 4.3 folds in Cd-transformed cells and 7.2 folds in Cd-tumorigenic cells. No change was found n the sequence of overexpressed EF-1beta p31 at different stages of 16HBE cells transformed by CdCl2. Overexpression of human EF-1beta p31 is positively correlated with malignant transformation of 16HBE cells induced by CdC12, but is not correlated with DNA mutations.

Study on malignant transformation of human bronchial epithelial cells induced by glycidyl methacrylate

To study the malignant transformation of human bronchial epithelial cells induced by glycidyl methacrylate (GMA). 16HBE cells were treated multiple times with GMA at concentrations of 1, 2, 4 and 8 microg/ml. Cellular biological characteristics of malignant transformation were identified by the tests of conA, colony forming frequency on soft agar, scanning electron microscope and tumorigenesis in nude mice. Test of immunocytochemical detection was also applied to confirm the derivation of cell and tumor. Groups of solvent control (DMSO) and positive control (MCA) were also performed at the same time. Transformed foci could be observed after the cells were treated by GMA at concentrations from 1 to 8 microg/ml. The number of transformation foci increased with the concentration of GMA. Transforming rate in 8 microg/ml group (8.48 x 10(-6)) was significantly higher (P < 0.01) than that of solvent control group (4.5 x 10(-7)). The transformed cells lost contact inhibition and exhibited a crossover growth in culture dish. They also could grow in semi-solid agar and showed dose-reaction relations with the concentration of GMA. The colony forming frequency in 2, 4 and 8 microg/ml group was 1.20 per thousand, 2.35 per thousand and 5.70 per thousand respectively, which were higher than that of solvent control group (P < 0.01). The transformed cells could be agglutinated by low concentration of conA. Microvilli on the surface of transformed cells increased and became strong and long under scanning electron microscope. The transformed cells could form subcutaneous tumor in nude mice which was diagnosed as squamous cell carcinoma in morphology. Expression of cytokeratin (CK) was detected in both 16HBE cells and tumor formed in nude mice. GMA could induce the malignant transformation of 16HBE cells. This research system might provide a potential tool and lay a foundation for the study of the molecular mechanism of carcinogenesis induced by GMA.

Malignant Transformation and Abnormal Expression of Eukaryotic Initiation Factor in Bronchial Epithelial Cells Induced by Cadmium Chloride

To analyze the relationship between malignant transformation and abnormal expression of eukaryotic initiation factor 3 (eIF3 p36) in human bronchial epithelial (16HBE) cells induced by cadmium chloride (CdCl2). 16HBE cells were treated several times with different concentrations of CdCl2. Tumorigenic potential of transformed cells was identified by assays for anchorage-independent growth in soft agar and for tumorigenicity in nude mice after the 35th passage. Total RNA was isolated from 16HBE cells induced by CdCl2, including non-transformed, Cd-transformed, and Cd-tumorigenic cell lines. Special primers for eIF3 p36 were designed and the expression of eIF3 mRNA in different cell lines was detected with fluorescent quantitative-polymerase chain reaction technique (FQ-PCR). The 35th passage of 16HBE cells transformed by CdCl2 exhibited overlapping growth. Compared with the non-transformed cells, colonies of transformed cell lines in soft agar showed statistically significant increases and dose-dependent effects (P<0.01). All Cd-induced transformed cell lines formed tumors in nude mice within 2 weeks of inoculation, but none of the mice injected with non-transformed cells showed tumors even after 3 weeks. All tumors were pathologically identified as poorly differentiated squamous cell carcinoma. The eIF3 p36 genes in different stages of 16HBE cells transformed by CdCl2 were elevated as compared with the non-transformed control (P<0.01), and the eIF3 expression increased with the degree of cell malignancy. CdCl2 is capable of inducing morphological transformation in 16HBE cells and transformed cells are potentially tumorigenic. Over-expression of eIF3 p36 is positively correlated with malignant transformation of 16HBE cells induced by CdCl2 and may be one of the molecular mechanisms potentially responsible for carcinogenesis due to Cd.

Silencing of N-Ras Gene Expression Using shRNA Decreases Transformation Efficiency and Tumor Growth in Transformed Cells Induced by Anti-BPDE

Anti-benzo[a]pyrene-trans-7,8-diol-9,10-epoxide (anti-BPDE) is the most important metabolite of benzo[a]pyrene which is a ubiquitous environmental pollutant, and may cause human cancer, especially of the lung. Ras genes (H, K, and N) are activated in 40% of human tumors and may contribute to carcinogenesis. Here, we used malignant human bronchial epithelial cells transformed by anti-BPDE (16HBE-T) to help characterize possible molecular mechanisms of carcinogenesis. We compared H-, K-, and N-Ras mRNA and protein expression levels in 16HBE-T cells and untransformed control 16HBE cells (16HBE-N), using reverse transcription-PCR (RT-PCR) and Western blotting. We further used short hairpin RNA to silence N-Ras gene expression in 16HBE-T cells to determine the effects of silencing on the cell cycle, transformation efficiency and tumor growth. We observed overexpression of H-, K-, and N-Ras genes at both mRNA and protein levels in 16HBE-T cells, compared with 16HBE-N cells. Silencing of N-Ras in 16HBE-T cells using stable RNA interference increased the proportion of cells in G(0)/G(1) phase, decreased the proportion in S-phase, decreased transformation efficiency, and inhibited tumor growth. Our findings suggest that overexpression of N-Ras gene plays an important role in malignant transformation of 16HBE cells by anti-BPDE. N-Ras gene may be a useful target for gene therapy.