Membrane Protein Alterations Associated with Anticancer Drug Resistance in Mouse Lymphoblastic Leukemia L1210 Cells

항암제에 내성인 생쥐의 백혈병세포 L1210의 세포막 단백질의 변환

Multidrug resistance(MDR) phenotype is frequently observed in animal and human cancer cell lines selected for in vitro resistance to a single chemotherapeutic agent. It is characterized by the diminished drug accumulation and is related to the drug efflux mechanism in resistant cells. In the present study, adriamycin resistant cells(L1210-$AdR_6$ : $10^{-6}M$ adriamycin, $-AdR_5$ : $10^{-5}M$) and vincristine resistant cells (L1210-$VcR_7$ : $10^{-7}M$ vincristine, $-VcR_6$ : $10^{-6}M$) were produced from mouse lymphoblastic leukemia cell line L1210. Growth profiles of survived cells were observed for 5 days with MTT(thiazolyl blue) assay and resistance was compared with $IC_{50}$(drug concentration of 50% survival reduction in absorbance). Resistant cells proliferated more slowly than sensitive cell. Doubling times were 29.7hr in L1210, 68.7hr in L1210-$AdR_5$ and 58.2hr in $-VcR_6$. MDRs expressed as resistance factor were as follows, L1210-$AdR_5$ was 76.4 times for vincristine, L1210-$VcR_6$ was 96.4 times for adriamycin. The cell membrane proteins with three different M.W. were recognized to be related resistance, 220, 158, and 88 kd in L1210-$AdR_5$, 158, 140 and 88 kd in L1210-$VcR_6$ by SDS-PAG electrophoresis. Cell surface membrane proteins were identified by radio-iodination and autoradiogram, their molecular weights were 158, 72.8, and 42.4 Kd in L1210-$VcR_6$.

Adriamycin과 vincristine 각각에 내성인 생쥐의 림프아세포성 백혈병세포 L1210세포의 특성과 내성관계 단백질을 찾아내고 항암제의 세포내 분포를 관찰하였다. 항암제의 내성생성은 adriamycin이 $10^{-5}M$과 $10^{-6}M$에서 자란 세포를 L1210-$AdR_5$와 $-AdR_6$로 하고 vincristine은 $10^{-6}M$과 $10^{-7}M$에서 자란 세포를 L1210-$VcR_6$와 $-VcR_7$로 하였다. 감수성세포는 L1210으로 하였다. 내성세포의 성장속도는 감수성세포에 비해 느렸으며 doubling time은 L1210가 29.7시간, L1210-$AdR_5$가 68.7시간 $-VdR_6$가 58.2시간이었다. 복합내성은 내성인자로 표기되었고 L1210-$AdR_5$는 vincristine에 대해 76.4배, $-VcR_6$는 adriamycin에 대해 98.6배로 나타냈다. 감수성세포와 내성세포의 세포막 단백질을 비교한 결과 L1210-$AdR_5$에서는 220, 158, 88 Kd의 내성관계단백질이 나타났고 $-VcR_6$에서는 158, 140 및 88Kd의 내성관계단백질이 관찰되었다. 세포막 표면단백질을 $^{125}I$로 결합시켜 자가방사선상으로 분석하였다. 세포막 표면단백질에 결합되는 $^{125}I$의 정도는 L1210에 0.95% L1210-$AdR_5$에 5.4%, $-VcR_6$에 1.7%였다. 세포막표면단백질은 L1210-$AdR_5$에서는 158, 72.8 및 42.4 Kd의 단백질, $-VcR_6$에서는 300, 158, 72.8 및 42.4 Kd의 단백질이 관찰되었다.