Methods: L-Maurocalcine (L-MCa), a peptide derived from scorpion venom was radiolabeled with 125I using the lactoperoxidase method. We achieved a specific activity of 45Mbq/nmole. In vitro studies with 125I-L-MCa in DAOY cells (human medulloblastoma) were studied in order to analyze the uptake of the peptide. 125I-L-MCa was injected intravenously in mice through tail vein and bio-distribution was studied using single photon emission tomography/computed tomography (SPECT/CT).
Results: The cellular uptake of the 125I-L-MCa in DAOY cells was time and dose dependent suggesting that the radiolabeled peptide retains the biological property after radiolabeling. We have observed no loss of cell viability upon uptake of 125I-L-MCa, favoring that this peptide has potential for use in in vivo studies. The distribution of the 125I-L-MCa in mice revealed its uptake in the liver, kidney and stomach. Interestingly the 125I-L-MCa was cleared from the circulation 24h post injection, thus providing another advantage for its use in in vivo studies.
Conclusions: In the present study we have shown the uptake of 125I-L-MCa in DAOY cells. Further, the 125I-L-MCa when injected in mice localized to the liver, kidney and stomach as revealed by SPECT/CT. Cells labeled with 125I-L-MCa can possibly be tracked to their target site.