Improved radioimmunolocalization of human tumor xenografts following subcutaneous delivery of monoclonal antibodies

The localization of a radiolabeled murine monoclonal antibody reactive with choriocarcinomas to human choriocarcinoma xenografts following intravenous and subcutaneous injection was evaluated by gamma scanning and tissue sampling. Tumor xenografts were established in the popliteal node region of athymic nude mice after repeated innoculations of the hind foot pads with BEWO choriocarcinoma cells. In dual label specific antibody studies, tumor/non tumor uptake ratios following subcutaneous (resulting in considerable intralymphatic uptake) injection of 131 I-5F9.3 were significantly higher than those achieved post simultaneous intravenous injection of 125 I-5F9.3. Double label experiments with 131 I-5F9.3 and a nonspecific antibody, 125 I-UPC-10, following subcutaneous injection, demonstrated that the high localization to popliteal region tumors was largely due to antibody specificity. Gamma scans following subcutaneous antibody administration of specific antibody to tumor bearing animals showed tumors soon after subcutaneous injection, at times earlier than those typically seen following intravenous delivery. Similar subcutaneous injections showed little normal nodal uptake in BALB/c control animals on gamma scans. No correlation was seen between tumor localization by specific antibody between the intravenous and intralymphatic routes, implying a difference in the mechanisms of tumor uptake of antibody by these two routes. The subcutaneous approach to antibody delivery offers advantages over intravenous delivery in tumors of human origin, including higher tumor/non tumor ratios and earlier imaging times. This was true even though these tumors were many times larger than normal lymph nodes. This subcutaneous delivery advantage should be exploitable in imaging nodal metastases of human tumors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46825/1/259_2004_Article_BF00256630.pd

Mutations in TCF8 Cause Posterior Polymorphous Corneal Dystrophy and Ectopic Expression of COL4A3 by Corneal Endothelial Cells

Posterior polymorphous corneal dystrophy (PPCD, also known as PPMD) is a rare disease involving metaplasia and overgrowth of corneal endothelial cells. In patients with PPCD, these cells manifest in an epithelial morphology and gene expression pattern, produce an aberrant basement membrane, and, sometimes, spread over the iris and nearby structures in a way that increases the risk for glaucoma. We previously mapped PPCD to a region (PPCD3) on chromosome 10 containing the gene that encodes the two-handed zinc-finger homeodomain transcription factor TCF8. Here, we report a heterozygous frameshift mutation in TCF8 that segregates with PPCD in the family used to map PPCD3 and four different heterozygous nonsense and frameshift mutations in TCF8 in four other PPCD probands. Family reports of inguinal hernia, hydrocele, and possible bone anomalies in affected individuals suggest that individuals with TCF8 mutations should be examined for nonocular anomalies. We detect transcripts of all three identified PPCD genes (VSX1, COL8A2, and TCF8) in the cornea. We show presence of a complex (core plus secondary) binding site for TCF8 in the promoter of Alport syndrome gene COL4A3, which encodes collagen type IV α3, and we present immunohistochemical evidence of ectopic expression of COL4A3 in corneal endothelium of the proband of the original PPCD3 family. Identification of TCF8 as the PPCD3 gene provides a valuable tool for the study of critical gene regulation events in PPCD pathology and suggests a possible role for TCF8 mutations in altered structure and function of cells lining body cavities other than the anterior chamber of the eye. Thus, this study has identified TCF8 as the gene responsible for approximately half of the cases of PPCD, has implicated TCF8 mutations in developmental abnormalities outside the eye, and has presented the TCF8 regulatory target, COL4A3, as a key, shared molecular component of two different diseases, PPCD and Alport syndrome