[Role of cyclin D1 in carcinogenesis of human cells induced by quartz].
OBJECTIVE
To study the role of cyclin D1 in malignant transformation of human embryonic lung diploid fibroblasts (HELF) induced by quartz.


METHODS
pXJ41-cyclin D1 expressing sense and antisense cyclin D1 RNA were transinfected into malignant transformed HELF induced by quartz with DNA recombination and gene transduction. The expression of cyclin D1 was detected with hybridization in situ and immunohistochemistry methods to analyze changes in cell growth, double multiplication time, distribution of cell cycles, colony forming ability on soft agar, etc., before and after cyclin D1 transduction.


RESULTS
During the process of malignant transformation of HELF induced by quartz, cyclin D1 gene was overexpressed. Antisense pXJ41-cyclin D1 RNA could suppress the growth and proliferation of malignant transformed cells induced by quartz. Growth speed of antisense pXJ41-cyclin D1 transinfected cells decreased by 58.69% on the 8th day in culture, as compared to malignant transformed cells induced by quartz, and its double multiplication time prolonged from 21.0 h to 31.4 h. Antisense cyclin D1 RNA led to cell cycle arrest, resulting in lengthened G1 phase (proportion of cells in phase G1 increased to 52.7% from 45.1% and that of cells in phase S decreased to 33.1% from 40.3%). Colony forming rate reduced significantly and size of colony became smaller.


CONCLUSIONS
Abnormal expression of cyclin D1 in cells related to their malignant transformation induced by quartz. Highly expressed cyclin D1 could play an important role in maintaining the transformed phenotype of malignant cells.
Yan
Ke-xia
KX
National Institute of Occupational Health and Poisons Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
Liu
Bing-ci
BC
Shi
Xiang-lin
XL
You
Bao-rong
BR
Xu
Ming
M
Kang
Ning
N
Zhao
Chao-ying
CY
D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000096:biosynthesis* / Q000235:genetics; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D008168:Lung / Q000166:cytology*; D011791:Quartz / Q000633:toxicity*
D019938:Cyclin D1; D011791:Quartz