Nongnit Laytragoon-Lewin

miR-34a Expression, Cell Cycle Arrest and Cell Death of Malignant Mesothelioma Cells upon Treatment with Radiation, Docetaxel or Combination Treatment

Objective: Malignant mesothelioma (MM) is a highly aggressive tumour related to asbestos exposure. Histopathologically, the tumour is classified as epithelial, sarcomatoid or biphasic. To date, MM is still an incurable disease. Methods: To evaluate treatment strategies on MM cells, the effects of radiotherapy, docetaxel or a combination of both on MM cells derived from the sarcomatoid type ZL34 and the epithelial type M28K were investigated. The TP53 gene, micro-RNA expression, cell cycle distribution and cell death were assessed as indicators of treatment effects. Results: Despite the normal TP53 gene sequences in these cell lines, radiation-induced miR-34a expression was detected only in the M28K cells. Increasing G0/G1 cell numbers were detected in irradiated M28K and ZL34 cells. There was more radiation-induced cell death in M28K compared to ZL34 cells. The highest degree of cell cycle arrest at G2 and cell death in both cell types was obtained in the presence of docetaxel. The combination of docetaxel and radiation did not show any additive effects on miR-34a expression, cell cycle arrest or cell death in either the M28K or ZL34 cells. Conclusion: Microtubule formation and other related functions by docetaxel might be the most suitable treatment modulation in both sarcomatoid and epithelial types of MM.

Expression of Cyclins A, E and Topoisomerase II α correlates with centrosome amplification and genomic instability and influences the reliability of cytometric S-phase determination

BackgroundThe progression of normal cells through the cell cycle is meticulously regulated by checkpoints guaranteeing the exact replication of the genome during S-phase and its equal division at mitosis. A prerequisite for this achievement is synchronized DNA-replication and centrosome duplication. In this context the expression of cyclins A and E has been shown to play a principal role.ResultsOur results demonstrated a correlation between centrosome amplification, cell cycle fidelity and the level of mRNA and protein expression of cyclins A and E during the part of the cell cycle defined as G1-phase by means of DNA content based histogram analysis. It is shown that the normal diploid breast cell line HTB-125, the genomically relatively stable aneuploid breast cancer cell line MCF-7, and the genomically unstable aneuploid breast cancer cell line MDA-231 differ remarkably concerning both mRNA and protein expression of the two cyclins during G1-phase. In MDA-231 cells the expression of e.g. cyclin A mRNA was found to be ten times higher than in MCF-7 cells and about 500 times higher than in HTB-125 cells. Topoisomerase II α showed high mRNA expression in MDA compared to MCF-7 cells, but the difference in protein expression was small. Furthermore, we measured centrosome aberrations in 8.4% of the MDA-231 cells, and in only 1.3% of the more stable aneuploid cell line MCF-7. MDA cells showed 27% more incorporation of BrdU than reflected by S-phase determination with flow cytometric DNA content analysis, whereas these values were found to be of the same size in both HTB-125 and MCF-7 cells.ConclusionsOur data indicate that the breast cancer cell lines MCF-7 and MDA-231, although both DNA-aneuploid, differ significantly regarding the degree of cell cycle disturbance and centrosome aberrations, which partly could explain the different genomic stability of the two cell lines. The results also question the reliability of cytometric DNA content based S-phase determination in genomically unstable tumor cell populations.

Significance of phosphotyrosine proteins, Bcl-2 and p53 for apoptosis in resting b-chronic lymphocytic leukemia (CLL) cells

Signal transduction and apoptosis in B‐cell chronic lymphocytic leukemia (CLL) cells with a post‐germinal center (GC) phenotype were studied. Specific activation of the cells was induced by a combination of soluble anti‐CD40 monoclonal antibody and interleukin‐4 (CD40/IL‐4) and nonspecific activation with a combination of phytohemagglutinin, phorbol‐12‐myristate‐13‐acetate and ionomycin (chemical mixture). Less than 5% of these leukemia cells entered the cell cycle after activation, as indicated by the number of cells in G0/G1 phase. The protein tyrosine phosphorylation pattern and expression of the Bcl‐2 protein were specific in ex vivo CLL cells of each individual patient. Expression of the p53 protein was not detectable in these leukemia cells. Cross‐linking of the CD40/IL‐4 receptors on CLL cells significantly upregulated phosphotyrosine proteins and the p53 protein. In the presence of chemical mixture, downregulated phosphotyrosine proteins were detected. Alterations in Bcl‐2 expression were independent of cross‐linking with CD40/IL‐4 or chemical mixture. A high frequency of apoptotic cells was detected in cells that had downregulated phosphotyrosine proteins and Bcl‐2 protein. There was no correlation between induction of apoptosis and expression of p53 protein. Our results suggest that apoptosis in resting leukemia cells could occur prior to the cell cycle progression. Alterations in phosphotyrosine proteins and Bcl‐2 but not p53 might play an important role in the regulation of apoptosis in resting G0/G1 memory post‐GC B‐CLL cells.

The Combined Effects of Single-Nucleotide Polymorphisms, Tobacco Products, and Ethanol on Normal Resting Blood Mononuclear Cells

INTRODUCTION Tobacco and ethanol consumption are crucial factors in the development of various diseases including cancer. In this investigation, we evaluated the combined effects of a number of single nucleotide polymorphisms (SNPs), with ethanol and tobacco products on healthy individuals. METHODS Pure nicotine, cigarette smoke extract, and Swedish snuff (snus) extract were used. The effects were examined by means of in vitro cell cycle progression and cell death of peripheral blood mononuclear cells (PBMCs) obtained from healthy donors. RESULTS After 3 days, in vitro, resting PBMCs entered the S and G2 stage in the presence of 100 µM nicotine. The PBMCs only proceeded to S stage, in the presence of 0.2% ethanol. The nicotine- and ethanol-induced normal cell cycle progression correlated to a number of SNPs in the IL12RB2, Rad 52, XRCC2, P53, CCND3, and ABCA1 genes. Certain SNPs in Caspases 8, IL12RB2, Rad 52, MMP2, and MDM2 genes appeared to significantly influence the effects of EtOH-, snus-, and snus + EtOH-induced cell death. Importantly, the highest degree of cell death was observed in the presence of smoke + EtOH. The amount of cell death under this treatment condition also correlated to specific SNPs, located in the MDM2, ABCA1, or GASC1 genes. CONCLUSIONS Cigarette smoke in combination with ethanol strongly induced massive cell death. Long-term exposure to smoke and ethanol could provoke chronic inflammation, and this could be the initiation of disease including the development of cancer at various sites.

Single-Nucleotide Polymorphisms and Cancer Risk, Tumor Recurrence, or Survival of Head and Neck Cancer Patients

Objective: This paper aims at studying the influence of single-nucleotide polymorphisms (SNPs) on cancer risk, tumor recurrence, and survival in head and neck (H&N) cancer patients. Methods: A total of 45 SNPs in 41 genes were investigated. A total of 174 Caucasian H&N cancer patients and 245 healthy blood donors were enrolled in the study. Results: Ten SNPs were associated with H&N cancer risk, but the identified SNPs differed among males and females. Some of the SNPs were related to immune response genes. The immune response gene SNPs were also related to survival. In particular, we noted that the tumor necrosis factor alpha (TNFα) rs1800629 could have an influence on cancer risk, tumor recurrence as well as survival. Conclusion: Genetic variation of the TNFα rs1800629 might be useful as a biomarker in clinical decision-making since it was found to be related to cancer risk, tumor recurrence, and survival of H&N cancer patients.

Effect of cigarette smoking on circulating plasma miRNA in healthy individuals

Introduction & Aim: Breast cancer is a predominant neoplastic disease among women and regardless of the disease subtypes it has been proposed that genetic mutations and epigenetic alterations caused by environmental factors may affect tumor development and growth. Nitric Oxide (NO), a free radical, is a well-known antioxidant has various roles in normal physiology. However, NO is also an important element in tumor microenvironment and has been linked to tumor growth. NO production is elevated in various human tumors including breast cancer. NO dependent gene regulation and histone methylation has been shown in cancer cells. As NO promoted deamination of 5-meC, it can be hypothesized that NO exposure can induce C-T transition in cancer cells. To exploit this hypothesis, we aimed to evaluate gene promoter methylation of BT-20, T42D and MCF-7 cell lines upon NO treatment.Statement of the Problem: The greatest challenge for anticancer therapy is the tendency of malignant cells to develop multidrug resistance (MDR). This phenomenon is manifested as a decrease in drug uptake, an increase in drug efflux by ABC transporters, and the activation of detoxification systems (phase II metabolism, the glutathione system), among other mechanisms of the MDR phenotype. Recently, a new group of anticancer drugs known as epigenetic agents, histone deacetylase inhibitors (HDACIs), has shown better clinical results. They are more specific and less toxic, and are capable of sensitizing malignant cells to conventional anticancer drugs. However, HDACIs have also proven to induce the MDR phenotype. Since glutathione (GSH) is the main detoxification system present in all tissues, the present study focuses on the relation between treatment with valproic acid (an epigenetic drug) and the expression of GSH-related genes in HeLa cell cultures.

Single nucleotide polymorphisms might influence chemotherapy induced nausea in women with breast cancer

Background Women receiving FEC (5 fluorouracil, epirubicin and cyclophosphamide) chemotherapy (CT) for breast cancer (BC) often experience side effects such as nausea and vomiting. Individual variations of side effects occur in patients despite similar cancer therapy. The purpose of this study was to investigate a possible genetic background as a predictor for individual variations in nausea induced by CT. Methods 114 women were included in the study. All women received adjuvant CT for BC. Self-reported nausea and vomiting was recorded in a structured diary over ten days following treatment. Blood samples were collected before the treatment and used for the detection of 48 single nucleotide polymorphisms (SNPs) in 43 genes. SNPs from each individual woman were analyzed for their relation to the patient-reported frequency and intensity of nausea and vomiting. Results Eighty-four percent (n = 96) of the women reported acute or delayed nausea or combined nausea and vomiting during the ten days following CT. Three out of the forty-eight SNPs in the following genes: FAS/CD95, RB1/LPAR6 and CCL2 were found to be associated with a risk of nausea. Conclusion SNPs in the FAS/CD95, RB1/LPAR6 and CCL2 genes were found to be associated with nausea among women treated with adjuvant FEC for BC. SNPs analysis is fast and cost effective and can be done prior to any cancer therapy. The association between individual SNPs and severe side effects from FEC may contribute to a more personalized care of patients with BC.