형질전환된 생쥐 NIH/3T3 세포에서 Metallothionein이 Cisplatin의 내성에 미치는 영향
The Effect of Metallothionein on the Resistance to Cisplatin in Transfected Mouse NIH/3T3 Cells
대한암학회지 1997년 29권 4호 p.576 ~ 583
소속 상세정보
손명희/Myung Hee Sohn
곽재용/임창열/손명희/곽재용/임창열/Jae Yong Kwak/Chang Yeol Yim/Myung Hee Sohn/Jae Yong Kwak/Chang Yeol Yim
KMID : 0360319970290040576
Abstract
결론
Cisplatin의 내성발생의 원인으로서 metallothionein의 역할에 많은 논란이 있다. 이제까지
의 연구들은 metallothionein이 증가된 세포를 cadmium과 같은 중금속을 첨가하여 얻었다.
그러나 이런 독성이 강한 중금속들은 세포를 여러 방향으로 변형시킬 수 있다. 따라서 본
연구에서는 cisplatin의 세포내성에 metallothionein함량만의 역할을 규명하기 위해서 세포를
중금속에 노출시키지 않고 metallothionein을 constitutive하게 생성할 수 있도록 plasmid를
조성하여 생쥐 NIH/3T3세포를 형질전환하여 metallothionein의 함량만이 다른 형질전환세포
에서 cisplatin의 독성을 비교하였다.
MT세포에서는 metallothionein의 양은 대조군인 TM과 BPA세포에 비해 약 15배 더 많았
으나 세포수를 반절로 감소시킬 수 있는 cisplatin의 농도인 IC-50은 차이를 보이지 않았다.
결과적으로 세포 내 metallothionein의 함량에는 큰 차이가 있음에도 불구하고 cisplatin의
내성에는 차이를 보이지 않음으로 metallothionein의 증가만으로는 종양세포가 cisplatin에
대한 내성음 유발하기에는 불충분함을 보여 주었다.
#초록#
Purpose: Metallothionein is an intracellular cystein-rich thiol-containing protein.
Increased metallothionein content in tumor cells has been suggested to be a mechanism
of resistance to cisplatin. In most of previous studies evaluating the role of
metallothionein in cisplatin resistance, tumor cells were usually exposed to cadmium to
increase metallothionein content. Therefore, cisplatin resistance of the cells may be
related to cadmium exposure itself, which induces various changes in cell characteristics,
but not to increased metallothionein content. The purpose of this study is to evaluate
the role of metallothionein content alone in cellular resistance to cisplatin without
exposure of cells to cadmium.
Materials and Method: We measured the toxicity of cisplatin in mouse NIH/3T3 cells
that vary in their content of metallothionein as a consequence of transfection with a
plasmid that result in the constitutive expression of metallothionein. MT cells were
derived from NIH/3T3 cells by transfection with a plasmid containing the genome of
bovine papilloma virus and the mouse metallothionein-I, derived by the promoter for the
glucose-regulated protein of 78kD. Control cells were similary transfected with bovine
papilloma virus-based plasmids with the gene for metallothionein inverted and thus
separated from the promoter(TM), or deleted, along with promoter(BPA). The number of
copies of the plasmid were similar in each kind of transfected cells. Expression of
metallothionein required neither selection nor maintenance of cells in the presence of
heavy metals.
Results: Synthesis of metallothionein was 15-fold greater in the MT cells than in the
TM or BPA cells. The concentration of cisplatin sufficient to reduce the cells per well
by one-half(IC-50) was 0.40±0.075 uM in MT cells. In TM and BPA cells, it was 0.36
±0.035 uM and 0.423±0.032 uM. There were no significant differences in IC-50 between
three cell lines.
Conclusion: In spite of large differences between MT and control cells in their cellular
content of metallothionein, no differences in resistance to cisplatin were observed.
키워드
Metallothionein; Cisplatin; Transfection;
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