Binding with serum components favorably affects cellular uptake of 111In-oligonucleotide in a leukemia cell line.
OBJECTIVE
The influence of serum components on the intracellular uptake of an 111In-oligonucleotide (ODN) against mdr1 mRNA was investigated in the murine leukemia cell line, P388/S, and its mdr1-overexpressed P388/R.


METHODS
111In-ODNs naked and vectorized with lipids were analyzed for binding with serum components using high-performance liquid chromatography (HPLC). 111In-ODN was incubated in albumin and transferrin solutions. 111In-DTPA and 111In-mononucleotide were incubated in serum. Degradation of naked 111In-ODN was detected in phosphate buffered saline (PBS) and serum containing endonuclease S1. Cellular uptakes of naked and vectorized 111In-ODN in the above cells were examined with and without fetal calf serum (FCS).


RESULTS
Time-dependent binding of naked and vectorized 111In- ODN with serum components was observed throughout 24 hours. Transchelation of 111In to transferrin was not detected. HPLC profiles of 111In-DTPA and 111In-mononucleotide did not change in serum. Degradation of 111In-ODN by S1 was less remarkable in serum than in PBS. Specific accumulation of vectorized 111In-ODN in P388/R cells was achieved in culture with and without 10% FCS.


CONCLUSIONS
This study verified the intense binding of ODN with serum components, leading to no inhibition on ODN intracellular specific uptake. Binding with serum components protects 111In-ODN from degradation by endonuclease and thus may facilitate ODN transmembrane delivery.
Department of Biotracer Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan. bjingming@mail.goo.ne.jp
Jingming
J
Bai
Seigo
S
Kinuya
Kazuhiro
K
Shiba
Takatoshi
T
Michigishi
Norihisa
N
Tonami
D000818:Animals; D001692:Biological Transport; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000633:toxicity; D019008:Drug Resistance, Neoplasm; D006801:Humans; D007205:Indium Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use; D007700:Kinetics; D007941:Leukemia P388 / Q000378:metabolism* / Q000532:radiotherapy; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use
D007205:Indium Radioisotopes; D009838:Oligodeoxyribonucleotides; D004317:Doxorubicin