Immune response to racotumomab in a child with relapsed neuroblastoma.

Immunotherapy targeting ganglioside antigens is a powerful tool for the treatment of high risk neuroblastoma. However, only treatment with anti-GD2 antibodies has been used in clinical practice and other options may be pursued. We report the use of racotumomab, an anti-idiotype vaccine against N-glycolyl neuraminic acid (NeuGc)- containing gangliosides, eliciting an immune response in a child with relapsed neuroblastoma expressing the NeuGcGM3 ganglioside.

Role of tumor-derived granulocyte-macrophage colony-stimulating factor in mice bearing a highly invasive and metastatic mammary carcinoma.

We have examined the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in tumor-bearing BALB/c mice using the syngeneic F3II mammary carcinoma. In the present model, progression of subcutaneous tumors induced massive myelopoiesis in bone marrow and spleen due to GM-CSF secretion by tumor cells. In vitro, the addition of recombinant mouse GM-CSF (5- 25 ng/ml) caused a significant increase in F3II cell growth, either in the presence or absence of serum. Zymographic analysis of conditioned media from F3II monolayers showed that GM-CSF exerted a dose-dependent enhancement in the metalloproteinases MMP-9 (105 kD) and MMP-2 (70 kD), key enzymes in mammary tumor cell invasion. Our data suggest that ectopic GM-CSF production stimulates myelopoiesis and may also play an important role in tumor progression and metastasis formation.

Histopathological findings in a highly invasive mouse mammary carcinoma transfected with human tissue inhibitor of metalloproteinases-1.

We have transfected a full-lenght cDNA-encoding human tissue inhibitor of metalloproteinases-1 (TIMP-1) by lipofection in highly invasive F3II mouse mammary sarcomatoid carcinoma cells. In vitro, overexpression of TIMP-1 was associated with abrogation of metalloproteinase activity, extended doubling time, and a more flattened, epithelioid polyhedric morphology. Female Balb/c mice inoculated subcutaneously with TIMP-1 transfectant exhibited a prolonged tumor latency and tumor burden was significantly lower in early stages of tumor growth. Control F3II cells grew by invading the muscular and adipose layers of the subcutis, dermis, and dermal papillae. On the contrary, mammary carcinoma cells transfected with TIMP-1 grew without signs of active invasion of dermis. Tumors also revealed a decreased amount of necrosis and host inflammatory cell infiltrates. However, histological analysis did not demonstrate any change in vascular density. Animals bearing F3II tumors overexpressing TIMP-1 showed a significant reduction in the size of metastatic lung nodules. These data suggested that TIMP-1 overexpression may reduce local invasion and delay the progression of the metastatic disease in the present mammary tumor model.