The Study On The Malignant Transformation Of Immortalized Rat Alveolar Cells Type Ⅱ RLE-6TN Induced By Yunnan Tin Mine Dust

Objectives:The miner of Yunnan tin mine who were long time exposed to the tin mine dust has a high risk to lung cancer.The main cause is exposure to radon and radon daughters combined with the effects of arsenic-containing ore dust.The aim of this study is to explore the malignant transformation effects of Yunnan tin mine dust on immortalized rat alveolar cells typeⅡ(RLE-6TN)in vitro and observe the change of ultrastructural and PI as so as some oncogene and anti-oncogene protein.Methods:To identify the RLE-6TN cells with transmission electron microscope(TEM) and immunohistochemistry.RLE-6TN cells were reacted with the tin mine dust at the concentration of 200μg/ml and 50μg/ml for 72 hours on every other generation which were stopped in the 10th generation,including a negative control group.The characteristics of the cellular biology and the malignant transformation phenotype of cells were identified through observing the anchorage independent growth.By the TEM detect we observed the ultrastructural change of RLE-6TN cells which were reacted with the tin mine.The change of cell circle and proliferation index(PI)was observed by the flow cytometry(FCM).The SP-B,P53,MDM2 and FHIT were detected by IHC and the SP-C was detected by WB.Results:(1)The typical osmiophilic lamellar bodies were found in the RLE-6TN cells which not reacted with tin mine dust.SP-C was also detected by WB.Plenty of tin mine dust were found in the RLE-6TN cells after 24 hours react by tin mine dust. Degeneration and reduce of osmiophilic lamellar bodies,increase of rough endoplasmic reticulum,swelling of mitochondria and increase of euchromatin were also found.Some RLE-6TN cells were apoptosis.(2)The cell colonies which more than 50 cells in soft agar were found in the high concentration group cells in 25th generation,and the anchorage independent growth was appeared in 30th generation high and low concentration group cells.Cell clone was not found in control groups.High statistically significant difference was found between experimental groups and control group(P＜0.01).No statistically significant difference(P＞0.05)was found among the four experimental groups.(3)The percentage of G2/M + S increased in the 30th generation of high concentration group cells with FCM.The PI of the high concentration group cells were significantly high than that in the control group.However,the low concentration group cells do not has significant difference compared with the control group cells.(4)The results of IHC were SP-B(-),P53(+),MDM2(+),FHIT1(-)in high concentration group cells and SP-B(+),P53(-),MDM(-),FHIT(+)in control group.Conclusions:(1)Yunnan Tin mine dust can induce malignant transformation of RLE-6TN cells in vitro.(2)The malignant transformation of RLE-6TN cells induced by tin mine dust were in 25th generation of the high concentration group cells and in 30th generation of low concentration group cells.(3)The positive expression of P53,MDM2 and negative expression of FHIT were detected in malignant transformation of RLE-6TN cells induced by tin mine dust.