Abstract
We have compared the effectiveness in causing DNA strand breaks of 111In bound to DNA or free in aqueous solution with that of γ rays. Supercoiled DNA from pBR322 plasmid labeled with [3H]thymidine was purified and mixed with 111InCl3 in the absence or presence of diethylenetriaminepentaacetic dianhydride (DTPA), a metal chelator which prevents the binding of indium to DNA. The reaction mixtures were stored at 4°C to accumulate radiation dose from the decay of 111In. The DNA was then resolved by gel electrophoresis into supercoiled, nicked circular and linear forms, representing undamaged DNA, single-strand breaks (SSBs) and double-strand breaks (DSBs), respectively. The D0 values of pBR322 DNA exposed to γ radiation from an external 137Cs source and the decay of 111In dispersed in solution (+DTPA) are 3.1 ± 0.1 and 2.8 ± 0.1 Gy, respectively. In terms of accumulated 111In disintegrations cm-3 of plasmid DNA solution, the D0 value is 15.3 (±0.7) x 1010 disintegrations in the absence of DTPA and 38.2 (±1.1) x 1010 disintegrations in its presence. Since only 14.6 ± 5% of the 111In was bound to DNA in the absence of DTPA, an effective D0 for bound 111In of 3.4 (±1.1) x 1010 disintegrations is obtained. The 11-fold (range 9- to 17-fold) increased effectiveness of this Auger electron emitter when in proximity to DNA appears to be due mainly to the higher yield of SSBs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 193-198 |
| Number of pages | 6 |
| Journal | Radiation Research |
| Volume | 141 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 5 1995 |
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ASJC Scopus subject areas
- Biophysics
- Radiation
- Radiology Nuclear Medicine and imaging
Cite this
The effect of Indium-111 decay on pBR322 DNA. / Sahu, S. K.; Kassis, A. I.; Makrigiorgos, G. M.; Baranowska-Kortylewicz, Janina; Adelstein, S. J.
In: Radiation Research, Vol. 141, No. 2, 05.04.1995, p. 193-198.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The effect of Indium-111 decay on pBR322 DNA
AU - Sahu, S. K.
AU - Kassis, A. I.
AU - Makrigiorgos, G. M.
AU - Baranowska-Kortylewicz, Janina
AU - Adelstein, S. J.
PY - 1995/4/5
Y1 - 1995/4/5
N2 - We have compared the effectiveness in causing DNA strand breaks of 111In bound to DNA or free in aqueous solution with that of γ rays. Supercoiled DNA from pBR322 plasmid labeled with [3H]thymidine was purified and mixed with 111InCl3 in the absence or presence of diethylenetriaminepentaacetic dianhydride (DTPA), a metal chelator which prevents the binding of indium to DNA. The reaction mixtures were stored at 4°C to accumulate radiation dose from the decay of 111In. The DNA was then resolved by gel electrophoresis into supercoiled, nicked circular and linear forms, representing undamaged DNA, single-strand breaks (SSBs) and double-strand breaks (DSBs), respectively. The D0 values of pBR322 DNA exposed to γ radiation from an external 137Cs source and the decay of 111In dispersed in solution (+DTPA) are 3.1 ± 0.1 and 2.8 ± 0.1 Gy, respectively. In terms of accumulated 111In disintegrations cm-3 of plasmid DNA solution, the D0 value is 15.3 (±0.7) x 1010 disintegrations in the absence of DTPA and 38.2 (±1.1) x 1010 disintegrations in its presence. Since only 14.6 ± 5% of the 111In was bound to DNA in the absence of DTPA, an effective D0 for bound 111In of 3.4 (±1.1) x 1010 disintegrations is obtained. The 11-fold (range 9- to 17-fold) increased effectiveness of this Auger electron emitter when in proximity to DNA appears to be due mainly to the higher yield of SSBs.
AB - We have compared the effectiveness in causing DNA strand breaks of 111In bound to DNA or free in aqueous solution with that of γ rays. Supercoiled DNA from pBR322 plasmid labeled with [3H]thymidine was purified and mixed with 111InCl3 in the absence or presence of diethylenetriaminepentaacetic dianhydride (DTPA), a metal chelator which prevents the binding of indium to DNA. The reaction mixtures were stored at 4°C to accumulate radiation dose from the decay of 111In. The DNA was then resolved by gel electrophoresis into supercoiled, nicked circular and linear forms, representing undamaged DNA, single-strand breaks (SSBs) and double-strand breaks (DSBs), respectively. The D0 values of pBR322 DNA exposed to γ radiation from an external 137Cs source and the decay of 111In dispersed in solution (+DTPA) are 3.1 ± 0.1 and 2.8 ± 0.1 Gy, respectively. In terms of accumulated 111In disintegrations cm-3 of plasmid DNA solution, the D0 value is 15.3 (±0.7) x 1010 disintegrations in the absence of DTPA and 38.2 (±1.1) x 1010 disintegrations in its presence. Since only 14.6 ± 5% of the 111In was bound to DNA in the absence of DTPA, an effective D0 for bound 111In of 3.4 (±1.1) x 1010 disintegrations is obtained. The 11-fold (range 9- to 17-fold) increased effectiveness of this Auger electron emitter when in proximity to DNA appears to be due mainly to the higher yield of SSBs.
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U2 - 10.2307/3579047
DO - 10.2307/3579047
M3 - Article
VL - 141
SP - 193
EP - 198
JO - Radiation Research
JF - Radiation Research
SN - 0033-7587
IS - 2
ER -