Malignant transformation and abnormal expression of eukaryotic initiation factor in bronchial epithelial cells induced by cadmium chloride.
OBJECTIVE
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).


METHODS
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).


RESULTS
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.


CONCLUSIONS
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.
Department of Preventive Medicine, Guangzhou Medical College, Guangzhou 510182, Guangdong, China. gz-leizeng@163.com
Yi-Xiong
YX
Lei
Lian
L
Wei
Min
M
Wang
Gen-Rong
GR
Wu
Min
M
Li
D000818:Animals; D001483:Base Sequence; D001980:Bronchi / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019256:Cadmium Chloride / Q000494:pharmacology*; D002471:Cell Transformation, Neoplastic; D017931:DNA Primers; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D016133:Polymerase Chain Reaction
D017931:DNA Primers; D039642:Eukaryotic Initiation Factors; D019256:Cadmium Chloride