[Expression and sequence analysis of human MutS homologue 2 during different stages of human bronchial epithelial cells induced by cadmium chloride].
OBJECTIVE
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).


METHODS
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.


RESULTS
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.


CONCLUSIONS
The expression decreased and the mutation of hMSH2 gene may be the possible carcinogenic mechanism for CdCl2.
Zhou
Zhi-heng
ZH
School of Public Health and General Medicine, Guangzhou Medical College, Guangzhou 510182, China.
Lei
Yi-xiong
YX
Wang
Cai-xia
CX
Wang
Min
M
Wei
Lian
L
Ji
Wei-dong
WD