oxazolone and Melanoma

The gray, short-tailed opossum, Monodelphis domestica, has been used for photobiologic studies since 1984. The presence of a light-activated DNA repair pathway in the tissues of Monodelphis has been used to identify pyrimidine dimers in DNA as initiating events for a number of ultraviolet radiation (UVR)-induced pathologies of the skin and cornea. Furthermore, Monodelphis, unlike common laboratory rodents, is susceptible to the induction of melanoma by UVR alone.

Topics: Animals; Cornea; Dermatitis, Contact; Dinitrofluorobenzene; Disease Models, Animal; DNA Repair; Eye Neoplasms; Melanoma; Mice; Mice, Nude; Opossums; Oxazolone; Photobiology; Pyrimidine Dimers; Skin; Skin Neoplasms; Ultraviolet Rays; Urocanic Acid

The hyaluronan receptor LYVE-1 is expressed abundantly on the surfaces of lymphatic vessels and lymph node sinus endothelial cells from early development, where it has been suggested to function both in cell adhesion/transmigration and as a scavenger for hyaluronan turnover. To investigate the physiological role(s) of LYVE-1, we generated mice in which the gene for the receptor was inactivated by replacement with a beta-galactosidase reporter. LYVE-1(-/-) mice displayed an apparently normal phenotype, with no obvious alteration in lymphatic vessel ultrastructure or function and no apparent change in secondary lymphoid tissue structure or cellularity. In addition, the levels of hyaluronan in tissue and blood were unchanged. LYVE-1(-/-) mice also displayed normal trafficking of cutaneous CD11c(+) dendritic cells to draining lymph nodes via afferent lymphatics and normal resolution of oxazolone-induced skin inflammation. Finally, LYVE-1(-/-) mice supported normal growth of transplanted B16F10 melanomas and Lewis lung carcinomas. These results indicate that LYVE-1 is not obligatory for normal lymphatic development and function and suggest either the existence of compensatory receptors or a role more specific than that previously envisaged.

Topics: Animals; beta-Galactosidase; Carcinoma, Lewis Lung; CD11c Antigen; Cell Movement; Dendritic Cells; Dermatitis, Contact; Glycoproteins; Hyaluronic Acid; Inflammation; Lymph Nodes; Lymphatic Vessels; Melanoma; Membrane Transport Proteins; Mice; Mice, Knockout; Neoplasm Transplantation; Oxazolone

Artificial recombinant receptors may be useful for selectively targeting imaging and therapeutic agents to sites of gene expression. To evaluate this approach, we developed transgenes to express highly on cells a single-chain antibody (scFv) against the hapten 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one (phOx). A phOx enzyme conjugate was created by covalently attaching phOx molecules to polyethylene glycol (PEG)-modified beta-glucuronidase. Cells expressing phOx scFv but not control scFv receptors were selectively killed after exposure to ss-glucuronidase derivatized with phOx and PEG (phOx-beta G-PEG) and a glucuronide prodrug (p-hydroxy aniline mustard beta-D-glucuronide, HAMG) of p-hydroxyaniline mustard. Targeted activation of HAMG produced bystander killing of receptor-negative cells in mixed populations containing as few as 10% phOx-receptor-positive cells. Functional phOx scFv receptors were stably expressed on B16-F1 melanoma tumors in vivo. Treatment of mice bearing established phOx-receptor-positive tumors with phOx-beta G-PEG and HAMG significantly (P< or =.0005) suppressed tumor growth as compared with treatment with beta G-PEG and HAMG or prodrug alone. phOx was unstable in the serum, suggesting alternative haptens may be more suitable for in vivo applications. Our results show that therapeutic agents can be targeted to artificial hapten receptors in vitro and in vivo. The expression of artificial receptors on target cells may allow preferential delivery of therapeutic or imaging molecules to sites of transgene expression.

Topics: Aniline Mustard; Animals; Antibodies, Monoclonal; Cell Line, Tumor; Drug Delivery Systems; Gene Expression; Haptens; Immunotherapy; Injections, Intravenous; Melanoma; Mice; Neoplasms, Experimental; Oxazoles; Polyethylene Glycols; Prodrugs; Receptors, Cell Surface; Recombinant Proteins

A murine model of immune responsiveness had been adapted to study anergic conditions associated with neoplasia. Marked anergy observed in mice bearing L1210 leukemia and P-388 lymphoma is contrasted to the minimal immune depression associated with B-16 melanotic melanoma and Sarcoma 180J. The ability of N,N-bis(2-chloroethyl)-N-nitrosourea chemotherapy to reduce tumor burden without prolonged suppression of delayed cutaneous hypersensitivity is compared to the profound suppression of the cutaneous response observed with Adriamycin cytoreductive therapy. The applications of our model are discussed in relation to tumor-associated anergy, new approaches to the evaluation of pharmaceuticals, and studies of combined chemoimmunotherapy regimens.

Topics: Animals; Carmustine; Doxorubicin; Female; Hypersensitivity, Delayed; Leukemia, Experimental; Leukemia, Lymphoid; Melanoma; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Oxazoles; Oxazolone; Sarcoma 180; Skin