title: LHRH-conjugated magnetic iron oxide nanoparticles for detection of breast cancer metastases.
abstract: Targeted delivery of superparamagnetic iron oxide nanoparticles (SPIONs) could facilitate their accumulation in metastatic cancer cells in peripheral tissues, lymph nodes and bones and enhance the sensitivity of magnetic resonance imaging (MRI). The specificities of luteinizing hormone releasing hormone (LHRH) and luteinizing hormone/chorionic gonadotropin (LH/CG)- bound SPIONs were tested in human breast cancer cells in vitro and were found to be dependent on the receptor expression of the target cells, the time of incubation and showed saturation kinetics. In incubations with MDA-MB-435S.luc cells, the highest iron accumulation was 452.6 pg Fe/cell with LHRH-SPIONs, 203.6 pg Fe/cell with beta-CG-SPIONs and 51.3 pg Fe/cell with SPIONs. Incubations at 4 degrees C resulted in 1.1 pg Fe/cell. Co-incubation with the same ligands (betaCG or LHRH) decreased the iron accumulation in each case. LHRH-SPIONs were poorly incorporated by macrophages. Tumors and metastatic cells from breast cancer xenografts were targeted in vivo in a nude mouse model. LHRH-SPION specifically accumulated in cells of human breast cancer xenografts. The amount of LHRH-SPION in the lungs was directly dependent on the number of metastatic cells and amounted to 77.8 pg Fe/metastastic cell. In contrast, unconjugated SPIONs accumulated in the liver, showed poor affinity to the tumor, and were not detectable in metastatic lesions in the lungs. LHRH-SPION accumulated in the cytosolic compartment of the target cells and formed clusters. LHRH-SPIONs did not accumulate in livers of normal mice. In conclusion, LHRH conjugated SPIONs may serve as a contrast agent for MR imaging in vivo and increase the sensitivity for the detection of metastases and disseminated cells in lymph nodes, bones and peripheral organs.
authors.affiliation: Pennington Biomedical Research Center, LSU System, Baton Rouge, LA 70808, USA. Leuschc@pbrc.edu
authors.forename: Carola
authors.initials: C
authors.lastname: Leuschner
authors.forename: Challa S S R
authors.initials: CS
authors.lastname: Kumar
authors.forename: William
authors.initials: W
authors.lastname: Hansel
authors.forename: Wole
authors.initials: W
authors.lastname: Soboyejo
authors.forename: Jikou
authors.initials: J
authors.lastname: Zhou
authors.forename: Josef
authors.initials: J
authors.lastname: Hormes
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D016466:CHO Cells / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000494:pharmacology; D003287:Contrast Media; D006224:Cricetinae; D003412:Cricetulus; D004195:Disease Models, Animal; D005260:Female; D052203:Ferrosoferric Oxide / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000556:secondary*; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008264:Macrophages / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles; D011966:Receptors, LHRH / Q000378:metabolism; D012680:Sensitivity and Specificity; D012708:Sertoli Cells / Q000378:metabolism; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D002352:Carrier Proteins; D018997:Chorionic Gonadotropin, beta Subunit, Human; D003287:Contrast Media; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D052203:Ferrosoferric Oxide