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Experimental Study Of PSCA Specific MR Molecular Probe And Its In Vivo MRI In Nude Mice Model Grafted With Human PCa At 3.0 T

Posted on:2010-09-08Degree:DoctorType:Dissertation
Country:ChinaCandidate:J RenFull Text:PDF
GTID:1114360275472967Subject:Medical imaging and nuclear medicine
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Objective:1. To cultivate prostate cancer cell lines and to establish the nude mice model grafted with human PCa and to determine the expression of PSCA.2. To construct the PSCA specific MR molecular probe 7F5@GoldMag, and to examine its biochemical characteristics.3. To investigate the feasibility of in vitro and in vivo MRI of 7F5@GoldMag in PCa by using a clinical 3.0 T MR system.Methods:1. Prostate cancer cell lines were cultured and nude mice models were established. The expression of PSCA of prostate cancer cell lines and nude mice model was determined by using indirect immunofluorescence, immunocytochemistry, flow cytometry, western blotting and immunohistochemistry.2. The PSCA specific MR molecular probe 7F5@GoldMag was constructed by conjugating anti-human PSCA mAb 7F5 with GoldMagTM-CS nanoparticles, and the coupling efficiency was calculated. The specific binding capability for 7F5@GoldMag to prostate cancer cells was detected by using laser confocal microscopy, transmission electron microscope and flow cytometry.3. MR scan sequences were established by using a clinical 3.0 T MR scanner. GoldMagTM-CS nanoparticles solution in different concentration was scanned to ascertain the lowest concentration that can be detected by MR system. The feasibility of molecular imaging of PSCA specific MR probe 7F5@GoldMag in vitro and in vivo was investigated. After conventional scan, T2W images were obtained after the probe was injected into nude mice model through caudal vein 6 h, 12 h and 24 h later, respectively. Statistical analyses were performed to assess the statistical differences of tumor signal intensity using one-way ANOVA with SPSS 11.5 software package as parameters were normally distributed. p<0.05 was considered as statistically significant difference.Results:1. The LNCaP, PC-3 and SMMC-7721 cells were injected subcutaneously in nude mice and the tumor incidence rates were LNCaP 12.5% (1/8), PC-3 100% (8/8) and SMMC-7721 100% (8/8), respactively. The results of indirect immunofluorescence, immunocytochemistry, flow cytometry, western blotting and immunohistochemistry showed that PSCA had high level expression on the plasma membrane of LNCaP and PC-3 cells, while no positive findings on the plasma membrane of SMMC-7721 cells.2. The PSCA specific MR molecular probe (7F5@GoldMag) was successfully constructed. The results of laser confocal microscopy, transmission electron microscope and flow cytometry proved that 7F5@GoldMag can specific bind with LNCaP and PC-3 cells.3. The T2WI signal intensity of GoldMagTM-CS was significantly lower than that of agarose gel even if the former was diluted by 640 times. 7F5@GoldMag could specificly decrease T2WI signal intensity of LNCaP and PC-3 cells in vitro.4. After the probe 7F5@GoldMag was injected into nude mice model through caudal vein 6 h, 12 h and 24 h later, T2WI signal intensity of PC-3 tumor was significantly lower than that of conventional scan (ANOVA, F=43.675, p=0.000). After the probe was injected 12 h later, the signal intensity showed further decrease than 6 h later (p=0.001). The tumor signal intensity showed no significant difference between 12 h and 24 h (p=0.145). While the signal intensity of control groups didn't show significant difference after injection of 7F5@GoldMag and non-related IgG@GoldMag, respectively.Conclusion:1. The PSCA specific MR molecular probe (7F5@GoldMag) was successfully constructed by conjugating anti-human PSCA mAb 7F5 with GoldMagTM-CS nanoparticles. It could specificly bind with PSCA positive prostate cancer cells.2. 7F5@GoldMag has target-directed enhancement effect in prostate cancer cell lines in vitro and in nude mice model grafted with PC-3 in vivo using a clinical 3.0 T MR scanner. It may therefore be a new noninvasive specific MR molecular probe in early-stage diagnosis of prostate carcinoma in the future.
Keywords/Search Tags:prostate carcinoma, prostate stem cell antigen, monoclonal antibody, GoldMag nanoparticles, magnetic resonance imaging, molecular imaging
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