Preparation and in vitro evaluation of 131I-BmK CT as a glioma-targeted agent.
OBJECTIVE
Buthus martensi Karsch (BmK) CT, a kind of scorpion toxin peptide, was found to inhibit glioma cell proliferation in previous researches. (131)I-BmK CT may have more inhibition effect and could be used as a glioma cell-targeted therapy and imaging agent. The purpose of this study was to investigate whether (131)I-BmK CT could specifically conjugate with C6 glioma cell and induce glioma cell inhibition in vitro.


METHODS
After cloning, expression, and purification, BmK CT was labeled with (131)I by indirect labeling (Bolton-Hunter method). The cell conjugation experiment was performed to investigate the connection between the reciprocal of cell conjugation rate and the reciprocal of cell count. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) method and flow cytometry were used to detect the inhibition effect of BmK CT and (131)I-BmK CT on glioma cell proliferation.


RESULTS
(131)I-BmK CT was successfully prepared with the overall yield of 34.5%. The cell conjugation experiment indicated that (131)I-BmK CT could specifically conjugate with C6 cells. MTT tests indicated that both BmK CT and (131)I-BmK CT could inhibit C6 growth. The ability of (131)I-BmK CT to inhibit cell growth is superior to that of BmK CT. The inhibitory rate (IR) of glioma cells was 60.5% (p < 0.01) at the concentration of 2 microg/mL with BmK CT. And the IR was 71.2% (p < 0.01) at the radioactivity concentration of 50 microCi/mL (concentration was much lower than 2 microg/mL) with (131)I-BmK CT. BmK CT could block the C6 glioma cell cycle in the G0/G1 stage. (131)I-BmK CT blocked the cell cycle in the S stage (the proportions of C6 in the S, G0/G1, and G2/M phases were 24.5% +/- 0.4% vs. 44.0% +/- 2.3%, 63.9% +/- 0.6% vs. 51.8% +/- 1.6%, and 11.6% +/- 1.0% vs. 4.3 +/- 0.7% [p < 0.05], respectively, at an initial radioactivity concentration of 50 microCi/mL).


CONCLUSIONS
On the basis of cytology experiments, it was found that (131)I-BmK CT could specifically conjugate with C6 glioma cell and inhibit cell growth. Hence, it may be used as a glioma-targeted agent.
Zhao
Jinhua
J
Department of Nuclear Medicine, The First People's Hospital, Shanghai Jiaotong University, Shanghai, People's Republic of China. zjh1963@gmail.com
Qiao
Wenli
W
Zhang
Yuna
Y
Shao
Xiaoxia
X
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005434:Flow Cytometry; D018316:Gliosarcoma / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007553:Isotope Labeling; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D012604:Scorpion Venoms / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
C516430:BmK CTa protein, Buthus martensii; D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D012604:Scorpion Venoms