ABSTRACT
Female mice of inbred strain CBA do not reject syngeneic male skin grafts even though they mount a T-cell response against the male-specific HY antigen. We show that local immunostimulation performed by injecting cytokines and Toll-like receptor ligands in close vicinity to the graft causes rejection. We feel that this approach should be tested in tumor-bearing human patients in combination with antitumor vaccination. Relief of intratumor immunosuppression may increase considerably the fraction of patients who respond to vaccination directed against tumor antigens recognized by T cells.
Subject(s)
Disease Models, Animal , Graft Rejection/chemically induced , Immune Tolerance/immunology , Immunization/methods , Neoplasms/therapy , Adoptive Transfer , Animals , Cytokines/adverse effects , Cytokines/immunology , DNA Primers/genetics , Female , Immunization/adverse effects , Male , Mice , Mice, Inbred CBA , Neoplasms/immunology , Reverse Transcriptase Polymerase Chain Reaction , Sex Factors , Skin Transplantation/methodsABSTRACT
MMTV/neu transgenic mouse line is a well-documented model for studying HER2/neu-related breast cancer. Approximately 80% of these mice develop mammary tumors by 11 months of age, whereas a small percentage appears to have naturally acquired resistance to HER2/neu tumorigenesis. To identify factors responsible for tumor resistance in these transgenic mice, comparative genetic profiling was used to screen alterations in gene expression in the mammary gland. A novel gene, the RAS association domain (RalGDS/AF-6) family 3 (Rassf3), which belongs to a family of RAS effectors and tumor suppressor genes, was identified. Data indicated 1) that Rassf3 is overexpressed in mammary gland of tumor-resistant MMTV/neu mice compared to tumor-susceptible MMTV/neu littermates or non-transgenic mice, and 2) Rassf3 is significantly up-regulated in neu-specific mouse mammary tumors compared to adjacent normal tissues. In vitro overexpression of RASSF3 inhibited cell proliferation in HER2/neu positive human and mouse breast cancer cell lines, possibly through induction of apoptosis. A novel MMTV/Rassf3-neu bi-transgenic mouse line, overexpressing Rassf3 and neu genes in mammary glands, was established. Mammary tumor incidence in bi-transgenic mice was delayed compared to their MMTV/neu+/- littermates. These data suggest that Rassf3 may influence mammary tumor incidence in MMTV/neu transgenic mice.
Subject(s)
Breast Neoplasms/genetics , Genes, erbB-2 , Mammary Neoplasms, Experimental/genetics , Monomeric GTP-Binding Proteins/genetics , Animals , Apoptosis , Base Sequence , Breast Neoplasms/pathology , Cell Survival , DNA Primers , Female , Genes, Tumor Suppressor , Humans , Mammary Neoplasms, Experimental/pathology , Mice , Mice, Transgenic , Molecular Sequence Data , Monomeric GTP-Binding Proteins/physiology , Rats , Reverse Transcriptase Polymerase Chain Reaction , TransfectionABSTRACT
Human prolactin (hPRL) has been implicated to have a pathological role in breast cancer and play a critical role in mammary gland development. The hPRL antagonist, G129R, has been shown to induce breast cancer cell apoptosis. 9,10-Dimethyl-1,2-benzanthracene (DMBA), a potent mammary gland carcinogen, induces hormone responsive mammary tumor formation in rodents. To investigate the effects of hPRL and its counterpart, G129R, on mammary gland development and tumorigenesis, transgenic mice that express hPRL or G129R under the regulation of the metallothionein (Mt) promoter were generated. Mammary glands from virgin female transgenic mice at the ages of 12, 24, and 36 weeks were used to compare the effect of hPRL and G129R in various developmental stages. Mammary gland whole mount comparisons between transgenic mice and their littermates revealed a significant increase in ductal branching and lobular bud formation in hPRL transgenic mice; whereas a drastic decrease in ductal branching and lobular bud formation was observed in the mammary glands of G129R transgenic mice. In addition, total RNA isolated from the mammary glands of transgenic mice at the three different ages was analyzed on Affymetrix GeneChip Mouse Expression 430A chips (MOE430A). Microarray data revealed alteration to the gene expression levels, greatest at 12 and 36 weeks. Furthermore, hPRL and G129R transgenic mice, as well as their littermates, were treated with multiple doses of DMBA and the rate of mammary tumor formation and survival were compared. The tumor rates in the G129R transgenic mice were significantly reduced (18% at 28 weeks) as compared to that of either NTG (39%) or hPRL (40%). On the other hand, the tumor appearance is significantly earlier in the PRL transgenic group as compared to that of controls. Taken together, the data further confirmed the inhibitory effects of G129R in mammary gland development, which translates to a resistance to DMBA-initiated breast tumorigenesis.
Subject(s)
Mammary Glands, Animal/drug effects , Mammary Neoplasms, Animal/physiopathology , Prolactin/pharmacology , 9,10-Dimethyl-1,2-benzanthracene/toxicity , Animals , Apoptosis , Carcinogens/toxicity , Cell Transformation, Neoplastic , Female , Mammary Glands, Animal/growth & development , Metallothionein , Mice , Mice, Transgenic , Prolactin/antagonists & inhibitors , Promoter Regions, GeneticABSTRACT
In the last years, adsorbed collagen was shown to form layers with a supramolecular organization depending on the substrate surface properties and on the preparation procedure. If the concentration of collagen and the duration of adsorption are sufficient, fibrillar collagen structures are formed, corresponding to assemblies of a few molecules. This occurs more readily on hydrophobic compared to hydrophilic surfaces. This study aims at understanding the origin of such fibrillar structures and in particular at determining whether they result from the deposition of fibrils formed in solution or from the building of assemblies at the interface. Therefore, type I collagen solutions with an increasing degree of aggregation were prepared, using the "neutral-start" approach, by ageing pH 5.8 solutions at 37 degrees C for 15 min, 2 or 7 days. The obtained solutions were used to investigate the influence of collagen aggregation in solution on the supramolecular organization of adsorbed collagen layers, which was characterized by X-ray photoelectron spectroscopy and atomic force microscopy. Polystyrene and plasma-oxidized polystyrene were chosen as substrates for the adsorption. The size and the density of collagen fibrils at the interface decreased upon increasing the degree of aggregation of collagen in solution. This is explained by a competitive adsorption process between monomers and aggregates of the solution, turning at the advantage of the monomers. More aggregated solutions, which are thus depleted in free monomers, behave like less concentrated solutions, i.e. lead to a lower adsorbed amount and less fibril formation at the interface. This study shows that the supramolecular fibrils observed in adsorbed collagen layers, especially on hydrophobic substrates, are not formed in the solution, prior to adsorption, but are built at the interface, through the assembly of free segments of adsorbed molecules.
