Diesel exhaust particulate matter dispersed in a phospholipid surfactant induces chromosomal aberrations and micronuclei but not 6-thioguanine-resistant gene mutation in V79 cells.

Diesel exhaust particulate material (DPM) was assayed for induction of chromosomal aberrations (CA), micronucleus (MN) formation, and 6-thioguanine-resistant (TG9 gene mutation in V79 cells as a dispersion in dipalmitoyl phosphatidylcholine (DPPC) in physiological saline, a simulated pulmonary surfactant. Filter-collected automobile DPM provided for the study was not organic solvent extracted, but was directly mixed into DPPC in saline dispersion as a model of pulmonary surfactant conditioning of a soot particle depositing in a lung alveolus. A statistically significant difference was found between treated and control groups at all concentrations tested in a CA assay.

In vitro genotoxicity of exhaust emissions of diesel and gasoline engine vehicles operated on a unified driving cycle.

Acetone extracts of engine exhaust particulate matter (PM) and of vapor-phase semi-volatile organic compounds (SVOCs) collected from a set of 1998-2000 model year normal emitter diesel engine automobile or light trucks and from a set of 1982-1996 normal emitter gasoline engine automobiles or light trucks operated on the California Unified Driving Cycle at 22 [degree]C were assayed for in vitro genotoxic activities. Gasoline and diesel PM were comparably positive mutagens for Salmonella typhimurium strains YG1024 and YG1029 on a mass of PM extract basis with diesel higher on a mileage basis; gasoline SVOC was more active than diesel on an extracted-mass basis, with diesel SVOC more active on a mileage basis. For chromosomal damage indicated by micronucleus induction in Chinese hamster lung fibroblasts (V79 cells), diesel PM expressed about one-tenth that of gasoline PM on a mass of extract basis, but was comparably active on a mileage basis; diesel SVOC was inactive.

[Establishment and identification of stable transfection of CHO and COS7 cells with TIF3cDNA].

Objective: To establish and identify CHO and COS7 cell lines transfected with TIF3cDNA.

Methods: CHO and COS7 cell lines transfected with TIF3cDNA were established with plasmid (pcDNA3.1/V5-His-TOPO) as the vector, using calcium phosphate inductive transfection techniques and G418 cell selection protocols.

Expression profile of eukaryotic translation factors in human cancer tissues and cell lines.

Several studies have demonstrated the overexpression of certain eukaryotic translation factors in human cancer cell lines and in malignant tissues. In this study, with human cancer cell lines derived from lungs, breast, prostate, and skin, we have examined the expression profile of 36 translation factors consisting of 27 initiation factors, 8 elongation factors, and 1 termination factor. Translation initiation factors 2C2 and 4E1 and translation elongation factors 1A2 and 1delta were found overexpressed (2- to 2000-fold) in many of the cancer cell lines compared to their corresponding normal cell lines.

Up-regulation of expression of translation factors--a novel molecular mechanism for cadmium carcinogenesis.

The molecular mechanisms potentially responsible for cadmium carcinogenesis were investigated by differential gene expression analysis of Balb/c-3T3 cells morphologically transformed with cadmium chloride. Differential display analysis of gene expression revealed overexpression of mouse Translation Initiation Factor 3 (TIF3; GenBank Accession Number AF 271072) and Translation Elongation Factor-1delta (TEF-1delta; GenBank Accession Number AF 304351) in the transformed cells compared with the control cells. The full length cDNAs for TIF3 and TEF-1delta were cloned and sequenced.

[Effect of aberrant DNA methylation on the expression of cancer-related genes in Cd-transformed cells].

Objective: To study aberrant DNA methylation potentially resulting in changes in the expression of cancer-related genes as a possible epigenetic mechanism for cadmium carcinogenesis.

Methods: 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).

[Antisense TIF3 reverses the oncogenic potential of CdCl2-transformed BALB/c-3T3 cells].

TIF3 (GenBank Accession Number AF 271072) is identified as a novel cadmium- responsive proto-oncogene. In order to determine whether the antisense TIF3 reverses the oncogenic potential of Cd-transformed BALB/c-3T3 cells or not, a stable expression system of CdCl2-transformed BALB/c-3T3 cells with the expression vector containing TIF3 cDNA in the antisense orientation using calcium phosphate and G418 selection protocols is firstly established. Then, the reversal of the oncogenic potential of these cells is tested by soft agar and nude mouse tumorigenicity assay.

Antisense inhibition of translation initiation factor 3 reverses its oncogenic potential.

Recently we have identified, cloned, and characterized the mouse Translation Initiation Factor 3 (TIF3, GenBank Accession Number AF 271072) as a novel cadmium-responsive proto-oncogene. Presently, additional studies regarding the oncogenic potential of TIF3 have been carried out. Transfection of NIH3T3 cells with the pcDNA3.

Molecular cloning and functional analysis of a novel cadmium-responsive proto-oncogene.

The molecular mechanisms potentially responsible for cell transformation and tumorigenesis induced by cadmium, a human carcinogen, were investigated by differential gene expression analysis of BALB/c-3T3 cells transformed with cadmium chloride (CdCl(2)). Differential display analysis of gene expression revealed consistent overexpression of mouse translation initiation factor 3 (TIF3; GenBank accession number AF271072) in the cells transformed with CdCl(2) when compared with nontransformed cells. The predicted protein encoded by TIF3 cDNA exhibited 99% similarity to human eukaryotic initiation factor 3 p36 protein.

Oncogenic potential of mouse translation elongation factor-1 delta, a novel cadmium-responsive proto-oncogene.

The molecular mechanisms potentially responsible for cadmium-induced cell transformation and tumorigenesis were investigated using Balb/c-3T3 cells transformed with cadmium chloride. Differential display analysis of gene expression revealed consistent and reproducible overexpression of a transcript in the transformed cells compared with the nontransformed cells. The full-length cDNA corresponding to the differentially expressed transcript was cloned and was identified as mouse translation elongation factor-1 delta subunit (TEF-1 delta; GenBank accession number ).