Alternative expression and sequence of human elongation factor-1 delta during malignant transformation of human bronchial epithelial cells induced by cadmium chloride / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Expression and sequence analysis of human MutS homologue 2 during different stages of human bronchial epithelial cells induced by cadmium chloride / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the expression and sequence of human MutS homologue 2 (hMSH2) during different stages of human bronchial epithelial (16HBE) cells induced by cadmium chloride (CdCl2).</p><p><b>METHODS</b>Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining (SP method) were used to measure the hMSH2 mRNA and protein expression in 16HBE cells and its different passage cells treated by CdCl2 (the 5th, 15th, 35th passage, and neoplasm cells from nude mice's tumor tissue). hMSH2 exon 6, hMSH2 exon 7, hMSH2 exon 8, hMSH2 exon 9, hMSH2 exon 12 of the 16HBE cells and neoplasm cells from nude mice's tumor tissue were amplified by polymerase chain reactions (PCR). The amplified DNA strips were purified. Then the exons were detected by DNA analysis.</p><p><b>RESULTS</b>During the passages of 16HBE cells treated with CdCl2, the expression of hMSH2 gene were decreased gradually. The hMSH2 gene mRNA and protein expression levels of the CdCl2 transformed 35th 16HBE cells and tumorigenic cells of nude mice significant decreased compared with non-transformed 16HBE cells (P < 0.01). In the tumorigenic cells of nude mice induced by CdCl2, there were thymine (T) deletion in 1st, 2nd and 7th site of hMSH2 exon 8, there were adenine (A) deletion in 20th and 182th site of hMSH2 exon 9, there were adenine (A) insertion in 241st site of hMSH2 exon 12. All the mutations were frame shift mutation.</p><p><b>CONCLUSION</b>The expression decreased and the mutation of hMSH2 gene may be the possible carcinogenic mechanism for CdCl2.</p>

Study on the ecological association between natural radioactivity and childhood leukemia in Guangdong province / 中华流行病学杂志

Objective This study was undertaken to evaluate the ecological association between terrestrial natural radionuclide,indoor radon concentration,natural radioactivity and leukemia incidence among children under 18 years of age.Methods Data were gathered from the disease surveillance program and literature reading while software SPSS 13.0 was used to calculate the Spearman's correlation.Results The incidence rates of childhood(0-18 year)leukemia showed significant differences in different places with the highest as 3.13/105in Jiangmen area and the lowest as 0.42/105 in Maoming area.The incidence in Jiangmen was 7.45 times higher than that in Maoming.There was a rank correlation between the incidence of childhood leukemia and the mean concentrations of natural radio-nuclides in soll(226Ra and 232Th),with a Positive correlation observed for overall leukemia(rs=0.70,P=0.011;rs=0.66,P=0.02 for226 Raand 232Th respectively)and acute lymphoblastic leukemia(ALL)(rs=0.66,P=0.019;rs=0.64,P=0.025 for 226 Ra and 232Th respectively).Associations between the incidence of childhood leukemia and the indoor γ radiation dose rate,the total annual average effective dose equivalent from natural background radiation were also analyzed(both rs=0.59,P=0.042).Conclusion The natural radioactivity was likely to be a causative factor for childhood leukemia in Guangdong.

Changes of expression and sequence of ERCC1 in cadmium chloride-induced transformed 16HBE cells at different stages / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the expression and sequence of ERCC1 gene in CdCl2-induced transformed human bronchial epithelial 16HBE cells at different stages.</p><p><b>METHODS</b>Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemcial staining (SP method) were used to measure the ERCC1 mRNA and protein expression in 16HBE cells at different passages treated with CdCl2 (the 5th, 15th, 35th passage, and neoplastic cells from tumors formed in nude mice). ERCC1 exon 3,exon 4 of the 16HBE cells and tumor cells from nude mice were amplified by polymerase chain reactions (PCR), the amplified DNA strips were purified,and the exons were detected by DNA analysis.</p><p><b>RESULTS</b>During the passages of 16HBE cells treated with CdCl2, the expression of ERCC1 gene was decreased gradually. The ERCC1 gene mRNA and protein expression levels of the CdCl2-transformed 35th passage 16HBE cells and tumor cells from nude mice were significantly decreased comparing with those in non-transformed 16HBE cells (P < 0.01). In the CdCl2-induced tumorigenic cells in nude mice, there was adenine (A) deletion in 1st site of ERCC1 exon 4. The mutation was frame shift mutation.</p><p><b>CONCLUSION</b>The decreased expression and mutation of ERCC1 gene may be the possible carcinogenic mechanism of CdCl2.</p>

Malignant transformation and abnormal expression of eukaryotic initiation factor in bronchial epithelial cells induced by cadmium chloride / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>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).</p><p><b>METHODS</b>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).</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Abnormal expression of eukaryotic translation factors in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the oncogenic potential of mouse translation initiation factor 3 (TIF3) and elongation factor-1delta (TEF-1delta) in malignant transformed human bronchial epithelial cells induced by crystalline nickel sulfide (NiS).</p><p><b>METHODS</b>Abnormal expressions of human TIF3 and TEF-1delta genes in two kinds of NiS-transformed cells and NiS-tumorigenic cell lines were investigated and analyzed by the reverse transcript polymerase chain reaction (RT-PCR) and fluorescent quantitative polymerase chain reaction (FQ-PCR), respectively.</p><p><b>RESULTS</b>RT-PCR analysis primarily showed that both human TIF3 and TEF-1delta mRNA expressions in two kinds of NiS-transformed cells and NiS-tumorigenic cell lines were increased as compared with controls. FQ-PCR assay showed that the levels of TIF3 expressions in the transformed cells and tumorigenic cells were 3 and 4 times higher respectively, and the elevated expressions of TEF-1delta cDNA copies were 2.7- to 3.5-fold in transformed cells and 4.1- to 5.2-fold in tumorigenic cells when compared with non-transformed cells, indicating that the over-expressions of human TIF3 and TEF-1delta genes were related to malignant degree of the cells induced by nickel.</p><p><b>CONCLUSIONS</b>These findings demonstrate that there are markedly abnormal expressions of TIF3 and TEF-1delta genes during malignant transformation of human bronchial epithelial cell lines induced by crystalline NiS. They seem to be the molecular mechanisms potentially responsible for human carcinogensis due to nickel.</p>

Expression change of TIF3 p36 at different stages of human bronchial epithelial cells transformed and induced by cadmium chloride / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the molecular mechanisms potentially responsible for carcinogenesis due to cadmium by detecting expression change of the translation initiation factor 3 (TIF3 p36) in those malignant transformation of human bronchial epithelial cell lines (16HBE) induced by cadmium chloride (CdCl(2)).</p><p><b>METHODS</b>The expression changes of TIF3 p36 were detected and analyzed at different stages of malignant cells (semi transformed cells, transformed cells and tumorigenic cells) induced by CdCl(2) solution with both reverse transcription PCR technique and sensitive fluorescent quantitative PCR assay.</p><p><b>RESULTS</b>Compared with non-transformed human bronchial epithelial cells, the results of fluorescent quantitative PCR assay showed that the semi-transformed cells, transformed cells and tumorigenic cells all expressed higher levels of TIF3 p36 mRNA (P < 0.01 or P < 0.05). As compared with the control cells, the TIF3 expressions at different stages of malignant transformation were 3.1 times, 5.9 times and 9.9 times higher respectively in the low dosage group of CdCl(2) (5 micromol/L); 7.1 times, 6.8 times and 14.8 times respectively in the middle dosage group of CdCl(2) (10 micromol/L); 3.6 times, 3.0 times and 9.1 times respectively in high of dose of CdCl(2) (15 micromol/L). These results showed that there was the positive correlation between overexpression levels of TIF3 p36 mRNA and the malignant degree of the cells, but they were not related to the dosages of cadmium.</p><p><b>CONCLUSION</b>There is significantly abnormal overexpression of TIF3 gene during malignant transformation of human bronchial epithelial cell line induced by cadmium chloride, and the TIF3 expression is associated with the malignant degree of the cells, which may be one of molecular mechanisms potentially responsible for the carcinogenesis due to cadmium.</p>

Telomerase SiRNA inhibits KB cell growth in human oral squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To test the telomerase SiRNA on telomerase mRNA and on KB cell growth of oral squamous cell carcinoma.</p><p><b>METHODS</b>We synthesized 21-nucleotide SiRNA duplexes with symmetric 2-nucleotide 3' overhangs corresponding to the target sequence (2 657 approximately 2 675 nucleotide downstream of the start codon) of telomerase mRNA. Telomerase activity, cell proliferation, cell cycle and apoptosis were measured after transfection.</p><p><b>RESULTS</b>Twenty one-nucleotide small interfering RNA (SiRNA) duplexes specifically suppressed expression of endogenous telomerase mRNA in human oral squamous carcinoma KB cells. This inhibitory effect lasted only for about 48 h after transfection. Telomerase activity reduction corresponded to the mRNA suppression. Cell proliferation decreased by 30% at 48 h after transfection and lasted for 120 h after treatment. This inhibitory effect resulted from the block of G(1) to S transition. Apoptosis was not involved in this process.</p><p><b>CONCLUSIONS</b>SiRNA is a powerful tool for studying gene function and can be used as gene-specific therapeutics.</p>

Effect of aberrant DNA methylation on the expression of cancer-related genes in Cd-transformed cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study aberrant DNA methylation potentially resulting in changes in the expression of cancer-related genes as a possible epigenetic mechanism for cadmium carcinogenesis.</p><p><b>METHODS</b>Genomic DNA isolated from CdCl(2)-transformed BALB/c-3T3 cells was digested with Mse1 (methylation non-sensitive) alone or with Mse1 and BstU1 (methylation sensitive). The resulting DNA was analyzed for aberrant methylation using PCR-based technique-Methylation-Sensitive Restriction Fingerprinting (MSRF). Several DNA fragments differentially methylated in the transformed cells identified by MSRF were confirmed by Southern hybridization analysis using the aberrantly methylated DNA fragments as the probes.</p><p><b>RESULTS</b>Aberrant DNA methylation was identified in the transformed cells. DNA sequencing and sequence similarity analysis identified one of the aberrantly methylated DNA fragments as the p16 tumor suppressor gene.</p><p><b>CONCLUSION</b>DNA hypermethylation is known to result in gene silencing, it appears that hypermethylation of p16 gene may represent a possible epigenetic mechanism for Cd-induced cell transformation and carcinogenesis.</p>