ABSTRACT
Objective To develop a probe for photoacoustic imaging and fluorescence imaging targeting integrin αvβ6 . Methods The probe was separated by RP‐HPLC .Molecular weight and the maximum absorption wavelength of the probe were detected by mass spectrum instrument and optical spectrum instrument . Various concentrations of the probe were detected by photoacoustic imaging and fluorescence imaging . The stability of the probe was evaluated when exposed under laser . Targeting of the probe on integrinαvβ6 was evaluated in cell uptake assay with integrinαvβ6 positive and negative cells . The minimum number of cells that could be detected by photoacoustic imaging and fluorescence imaging was also evaluated . Results The probe ICG‐peptide was separated from reaction mixture by RP‐HPLC .The probe had a retention time of 21 .4 minutes and m/z of 4 727 . The labeling ratio of the probe was 1∶1 . The maximum absorption wavelength of the probe was 790 nm . The photoacoustic signal was linearly dependent on the concentration of the probe . The fluorescence signal was linearly dependent on the concentration of the probe when the concentration was smaller than 1 .5 × 10 -5 mol/L . The lowest concentration of the probe that could be detected above the background by photoacoustic imaging and fluorescence imaging was 0 .09 × 10-5 mol/L and 0 .05 × 10-5 mol/L ,respectively . No obvious decrease of the photoacoustic signal was observed after the probe was scanned 20 times ( each time lasted for 1 min) by laser . There existed differences ( P <0 .001) in cell uptake of the probe with various concentrations and reaction time between A431 cells (αvβ6 positive) and 293T cells (αvβ6 negative) . Cell uptake was inhibited by the addition of 5μmol/L unlabeled peptide in A431 cells ( P = 0 .001 ) . The lowest number of the labeled A431 cells detected by photoacoustic imaging and fluorescence imaging was 0 .4 × 106 and 0 .05 × 106 ,respectively . Conclusions The dual functional photoacoustic and fluorescence probe targeting integrin αvβ6 was successfully developed . The targeting and sensitivity of the probe makes it potentially useful in early detection of αvβ6 positive tumors .
ABSTRACT
Objective Few researches are reported on the association of integrinαvβ6 with vaginal mucous infection and de-fense.This study aimed to investigate the effects of IL-6, TGF-β, and IFN-γon the expression of integrinαvβ6 in the vaginal epithelial cell line VK2/E6E7. Methods Immortalized human vaginal epi-thelial cells (VK2/E6E7) were cultured in vitro and treated with gra-dient concentrations of IL-6 (1, 10, 50, and 100 ng/mL), TGF-β(0.1, 1, 10, and 100 ng/mL), and IFN-γ(50, 500, 2500, and 5000 U/L) , respectively.After 48 hours, the cells were collected and total RNA extracted by the Trizol method to be reversely tran-scribed to cDNA. The expressions of integrin αand β6 subunit mRNA were detected by real-time quantitative PCR. Results In the IL-6-treated VK2/E6E7 cells, the integrin αand β6 subunit mRNA expressions were significantly lower in the 1 ng/mL and 10 ng/mL groups but remarkably higher in the 100 ng/mL group (1.14 ±0.12 and 1.37 ±0.25) than in the blank control (1.00 ±0.09) (P<0.05), and only the expression ofβ6 subunit mRNA was elevated in the 50 ng/mL group (P<0.05), with the expressions increased in a concentration-dependent manner.In the TGF-βtreated VK2/E6E7 cells, the expressions of integrinαandβ6 subunit mRNA were significantly lower in the 0.1 ng/mL and 1 ng/mL groups but remarkably higher in the 100 ng/mL group than in the blank control (1.00 ±0.09) (P<0.01), and only the expression ofβ6 subunit mRNA was elevated in the 10 ng/mL group (4.31 ±0.78, P<0.01), with the expressions increased in a concentration-dependent manner.In the IFN-γtreated VK2/E6E7 cells, the expressions of both integrinαandβ6 subunit mRNA were significantly lower in the 50 U/L, 500 U/L, 2500 U/L, and 5000 U/L groups than in the blank control (all P<0.01). Conclusion IL-6 and TGF-βhave an inhibitory effect the expression ofαvβ6 in VK2/E6E7 cells at low concentrations, which gradually diminishes with the increased concentration of inflammatory factors.In the early stage of inflammation, IFN-γcan effectively suppress the expression ofαvβ6 at a high concentration.However, with the progression of inflammation and decrease of its concentration, IFN-γloses its inhibi-tory effect and therefore does not help inflammation control.