Lethal Effects of Radiation and Platinum Analogues on Multicellular Spheroids of HeLa Cells

• 발행기관: 대한방사선종양학회
• 저자명: 홍성언(Seong Eon Hong)
• 간행물 정보: 『대한방사선종양학회지』제7권 제2호, 149~156쪽, 전체 8쪽
• 주제분류: 의약학 > 종양학
• 파일형태: PDF
• 발행일자: 1989.12.30

국문 초록

HeLa 세포의 Spheroid를 배양시켜 cis-platinum과 carboplatin으로 처리한 후 그 반응을 세포의 생존분획으로 분석하였다. 체외실험 model인 spheroid를 사용하여 platinum 유사체의 약효와 방사선 감수성을 평가하고 약제에 대한 단층 세포와 spheroid의 감수성 차이를 세포-생존곡선에서 규명하기 위하여 본 실험을 시행하였다. Cis-platinum 농도-곡선에서 spheroid의 Cq=3.4μM이고 Co=1.2μM이었다. 이것은 단충세포에 비하여 Co는 큰 변화가 없으나 Cq가 증가되어 cis-platinum이 저산소층 세포보다 활동적으로 분화하는 표면세포에 주로 작용하였으며, 반대로 carboplatin의 효과는 spheroid에 대한 (Co=15.0μM) 감수성이 단층세포 (Co=32.5μM)에 비하여 크게 증가되어, spheroid의 심층세포에 주로 작용하였다. 방사선과 carboplation의 병용효과를 세표 생존분획이 0.01 수준에서 isobologram으로 분석한 결과 상호작용으로 supra-additive 효과를 나타내었다. 따라서, carboplatin은 cis-platinum에 비하여 신장과 위장에 대한 독성작용이 적고, 방사선과 병용함으로써 더욱 효과적인 종양 치료에 중요한 역할을 할 것으로 기대한다.

영문 초록

Multicellular tumor spheroids of HeLa cells have been grown in a stare culture system. Samples of spheroids were exposed for 2 h to graded concentration of cis-platinum and its analogue, carboplatin. and then response assayed by survival of clonogenic cells. The purpose of present experiment is to clarify the effectiveness of these platinum compounds and to evaluate intrinsic radiosensitivity of cells using spheroids of HeLa cells as an experimental in vitro model. Variations of the drug sensitivity of monolayers as well as spheroids were also evaluated in cell-survival curves. In cis-platinum concentration-survival curve, there was a large shoulder extending as far as Cq=3.4 μM, after which there was exponential decrease in survival curve having a Co Value of 1.2 μM in spheroids. While the Co for the spheroids was essentially no significant change, but Cq value was larger than that of monolayers. This suggest that the effect of cis-platinum is greater in the monolayer with actively proliferaing cells than hypoxic one. In the corboplatin concentration-survival curves, the Co value of spheroids was 15.0 μM and the ratio with the Co from monolayer cell (32.5 μM) was 0.46, thus indicating that the spheroids had a greater sensitivity to carboplatin than monolayers. Therefore, 'the effect of carboplatin is mainly on the deeper layers of spheroids acting as hypoxic cell sensitizer. The enhanced effect was obtained for monolayer cells using combined X-ray and carboplatin treatment 2 hours before irradiation. The result shown in isobologram analysis for the level of surviving fraction at 0.01 indicated that the effect of two agents was truely supra-additive. From this experimental data, carboplatin has excited much recent interest as one of the most promising, since it is almost without nephrotoxicity and causes less gastrointestinal toxicity than cis-platinurn. Interaction between carboplatin and radiation might play an important role for more effective local tumor control.

키워드

Platinum analogues-radiation interaction Spheroid. HeLa cells Additive response