| Cancer has become the biggest cause of death in the world.Breast cancer,one of the most common cancer in women,occurs in the epithelial tissues.Millions of women around the world are suffering from breast cancer.Comprehensive molecular analysis of breast cancer shows that breast cancer is a collection of molecularly distinct neoplastic diseases of the breast.Breast cancers are heterogeneous,both in their pathology and in their molecular profiles.Different molecular subtypes of breast cancer,its clinical manifestations,prognosis and treatment are different.Triple negative breast cancer(TNBC)is a molecularly heterogeneous disease,characterized by a low expression of the estrogen receptor(ER),progesterone receptor(PR),and human epidermal growth factor receptor 2(HER-2).The significant growth and metastasis of TNBC tumors,coupled with fewer treatment options and a lack of recognized molecular targets for therapy,have resulted in relatively poorer outcome and higher mortality rates for patients with TNBC relative to those with other breast cancer subtypes.ICAM-1 plays an important role in breast cancer progression and metastasis.ICAM-1 overexpressed in human triple negative breast cancer(TNBC)cell lines and tissues is a potential molecular target and biomarker for TNBC therapy and diagnosis.The aim of this study was to prepare a novel TNBC-targeted probe.Physical and chemical properties of probe were determined and a series of biological evaluation in vivo and in vitro were also done to examine the prospects of TNBC diagnosis and treatment.In the second chapter,breast cancer cells ICAM-1 surface protein expression was evaluated by flow cytometry.The results showed that ICAM-1 was negative expression on non-TNBC cells(BT474 and MCF-7),the positive rates of TNBC cells(MDA-MB-231 and MDA-MB-453)were significantly higher than non-TNBC cells(BT474 and MCF-7)(Fig.1).TNBC cells exhibited about 6 to 11-fold higher ICAM-1 surface protein levels than non-TNBC cells.Immunohistochemical staining of MDA-MB-231 and MCF-7 xenografts was consistent with the flow cytometry result.In the third chapter,we investigate the radioiodination labeling method of anti-ICAM-1 antibody,and successfully prepared the stable 131I-aICAM1 probe.A series of evaluation of the probe were determined.131I-aICAM1 radiolabeling yield>90%,radiochemical purity>99%.In vitro stability of 131I-aICAM1 in PBS and fetal bovine serum at room temperature was determined,the radiochemical purity>80%after 2 d.indicating the 131I-aICAM1 had a good stability in vitro.Cell saturation experiments,cellular immunofluorescence and tissue autoradiography were used to evaluate the probe.The probe has good immunological activity and specificity,and can specifically bind to ICAM-1 on MDA-MB-231 cells with high affinity(Kd = 2.71 ± 0.20 nM).In the fourth chapter,the dose-escalation study showed that 125I-aICAM1 efficiently targeted MDA-MB-231 xenografts at antibody protein doses up to 10 ?g.From the results of SPECT imaging study,MDA-MB-231 tumor could be visualized clearly using 125I-aICAM1 at 48 h after injection,and the tumor accumulation increased over time with the uptake of 3.09 ± 0.09%ID/g,7.02 ± 0.99%ID/g,8.87 ± 0.92%ID/g,11.79 ± 2.15%ID/g and 15.10 ± 1.40%ID/g at 1,24,48,72 and 96 h after injection,respectively.The tumor-to-heart,tumor-to-liver and tumor-to-muscle ratios were 3.66± 0.34,5.36±0.50 and 29.70 ± 2.76,respectively,at 96 h after injection.While for 125I-mIgG,almost no MDA-MB-231 tumor uptake was observed at all time-points after injection.In the fifth chapter,we conducted radioimmunotherapy studies,131I-aICAM1 can significantly inhibit the growth of MDA-MB-231 tumors.125I-aICAM1 is a new potent tracer to detect ICAM-1 expression in vivo using SPECT.The probe is expected to provide information on the molecular typing of breast cancer.The feasibility of SPECT imaging with 125I-aICAM1 for noninvasively TNBC identification and corresponding image-guided tumor radiotherapy with 131I-aICAM1 will be demonstrated in the future. |
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