A new immunization and treatment strategy for mouse mammary tumor virus (MMTV) associated cancers

Mouse Mammary Tumor Virus (MMTV) causes mammary carcinoma or lymphoma in mice. An increasing body of evidence in recent years supports its involvement also in human sporadic breast cancer. It is thus of importance to develop new strategies to impair the development, growth and metastasis of MMTV-associated cancers. The signal peptide of the envelope precursor protein of this virus: MMTV-p14 (p14) is an excellent target for such strategies, due to unique characteristics distinct from its regular endoplasmic reticulum targeting function. These include cell surface expression in: Murine cancer cells that harbor the virus, human breast cancer (MCF-7) cells that ectopically express p14, as well as cultured human cells derived from an invasive ductal breast carcinoma positive for MMTV sequences. These findings support its use in signal peptide-based immune targeting. Indeed, priming and boosting mice with p14 elicits a specific anti-signal peptide immune response sufficient for protective vaccination against MMTV-associated tumors. Furthermore, passive immunization using a combination of anti-p14 monoclonal antibodies or the transfer of T-cells from immunized mice (Adoptive Cell Transfer) is also therapeutically effective. With reports demonstrating involvement of MMTV in human breast cancer, we propose the immune-mediated targeting of p14 as a strategy for prevention, treatment and diagnosis of MMTV-associated cancers

Cranberry Juice Constituents Impair Lymphoma Growth and Augment the Generation of Antilymphoma Antibodies in Syngeneic Mice

In addition to its nutritional value, cranberry juice has been effective in treating urinary tract infections. Various reports have also demonstrated its potential for inhibiting in vitro growth of transformed cell lines. Here we show that a fraction [nondialyzable material (NDM) of a molecular weight range 12,000-30,000 (NDM 12-30K)] derived from cranberry juice impairs in vitro growth and invasion through extracellular matrix of Rev-2-T-6 murine lymphoma cells. Furthermore, intraperitoneal injection of this fraction at nontoxic doses both inhibits the growth of Rev-2-T-6 tumors in vivo and enhances the generation of antilymphoma antibodies. These findings demonstrate the in vivo efficacy of cranberry components against malignant lymphoma in immune competent hosts

Identification of Dormancy-Associated MicroRNAs for the Design of Osteosarcoma-Targeted Dendritic Polyglycerol Nanopolyplexes

The presence of dormant, microscopic cancerous lesions poses a major obstacle for the treatment of metastatic and recurrent cancers. While it is well-established that microRNAs play a major role in tumorigenesis, their involvement in tumor dormancy has yet to be fully elucidated. We established and comprehensively characterized pairs of dormant and fast-growing human osteosarcoma models. Using these pairs of mouse tumor models, we identified three novel regulators of osteosarcoma dormancy: miR-34a, miR-93, and miR-200c. This report shows that loss of these microRNAs occurs during the switch from dormant avascular into fast-growing angiogenic phenotype. We validated their downregulation in patients’ tumor samples compared to normal bone, making them attractive candidates for osteosarcoma therapy. Successful delivery of miRNAs is a challenge; hence, we synthesized an aminated polyglycerol dendritic nanocarrier, dPG-NH₂, and designed dPG-NH₂-microRNA polyplexes to target cancer. Reconstitution of these microRNAs using dPG-NH₂ polyplexes into Saos-2 and MG-63 cells, which generate fast-growing osteosarcomas, reduced the levels of their target genes, MET proto-oncogene, hypoxia-inducible factor 1α, and moesin, critical to cancer angiogenesis and cancer cells’ migration. We further demonstrate that these microRNAs attenuate the angiogenic capabilities of fast-growing osteosarcomas <i>in vitro</i> and <i>in vivo</i>. Treatment with each of these microRNAs using dPG-NH₂ significantly prolonged the dormancy period of fast-growing osteosarcomas <i>in vivo</i>. Taken together, these findings suggest that nanocarrier-mediated delivery of microRNAs involved in osteosarcoma tumor–host interactions can induce a dormant-like state