SKOV-3 cell imaging by paramagnetic particles labeled with hairpin cell-penetrating peptides / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>The hairpin cell-penetrating peptides (hCPPs) demonstrate an interesting characteristic of conditioned activation by molecules. We hypothesized that hCPPs have the potential to selectively deliver a paramagnetic gadolinium probe into the matrix metalloproteinase 2 (MMP-2) positive human ovary adenocarcinoma cell lines, SKOV-3.</p><p><b>METHODS</b>hCPPs were synthesized and labeled with 1,4,7,10-tetraazacyclododecane-N,N',N'',N''' tetraacetic acid gadolinium (III) (Gd-DOTA) and fluorescein isothiocyanate (FITC) by f-moc strategy using a standard solid phase peptide synthesis protocol. MMP-2 expression and activity were demonstrated by reverse transcriptase polymerase chain reaction (RT-PCR) and zymography. Internalization and location of hCPPs in SKOV-3 cells were observed by fluorescein imaging and flow cytometery. Selective delivery of Gd-DOTA in SKOV-3 cells was observed by magnetic resonance imaging (MRI) and transmission electron microscopy (TEM).</p><p><b>RESULTS</b>The uptake of hCPPs by SKOV-3 cells depended on the activity of MMP-2. T1WI signals of SKOV-3 cells treated with Gd-DOTA-hCPPs suggested the uptake of Gd-DOTA-hCPPs increased in a time- (r = 0.990, P < 0.01) and concentration-dependent manner (r = 0.964, P < 0.001), but was inhibited by a MMP-2 inhibitor. Electron-dense particles observed in the cytoplasm and nucleus by transmission electron microscopy proved the intracellular penetration of gadolinium.</p><p><b>CONCLUSIONS</b>hCPPs can be used as an effective vector for an MRI molecular probe to assess the activity of MMP-2.</p>