Mechanism and functional consequences of loss of FOXO1 expression in endometrioid endometrial cancer cells.

The forkhead transcription factor FOXO1, a downstream target of phosphatidylinositol-3-kinase/Akt signalling pathway, regulates cyclic differentiation and apoptosis in normal endometrium, but its role in endometrial carcinogenesis is unknown. Screening of endometrial cancer cell lines demonstrated that FOXO1 is expressed in HEC-1B cells, but not in Ishikawa cells, which in turn highly express the FOXO1 targeting E3-ubiquitin ligase Skp2. FOXO1 transcript levels were also lower in Ishikawa cells and treatment with the proteasomal inhibitor was insufficient to restore expression. Lack of FOXO1 expression in Ishikawa cells was not accounted for by differential promoter methylation or activity, but correlated with increased messenger RNA (mRNA) turnover. Comparative analysis demonstrated that HEC-1B cells proliferate slower, but are more resistant to paclitaxel-mediated cell death than Ishikawa cells, which were partially reversed upon silencing of FOXO1 in HEC-1B cells or its re-expression in Ishikawa cells. We further show that FOXO1 is required for the expression of the growth arrest- and DNA-damage-inducible gene GADD45alpha. Analysis of biopsy samples demonstrated a marked loss of FOXO1 and GADD45alpha mRNA and protein expression in endometrioid endometrial cancer compared to normal endometrium. Together, these observations suggest that loss of FOXO1 perturbs endometrial homeostasis, promotes uncontrolled cell proliferation and increases susceptibility to genotoxic insults.

Malignant melanoma and fibrothecoma--an ovarian mixed tumor.

There are only a few cases of primary ovarian melanoma described in the literature. Here, we report a rare case of ovarian mixed neoplasm with parts of malignant melanoma and fibrothecoma in a 76-year-old female who was hospitalized for a cataract operation. To our knowledge, cases of a combination of malignant melanoma and fibrothecoma in the ovary have not been described. In this study, new markers for malignant melanoma (S-100, tyrosinase mRNA) were also tested.

An animal model for anaplastic large cell lymphoma in the immunocompetent syngeneic C57Bl/6 mouse.

We report on the analysis of a murine anaplastic lymphoid cell line TS1G6, established recently by interleukin (IL)-9 transfection. TS1G6 revealed a highly characteristic pattern of large anaplastic cells with mononuclear, binuclear, or multinuclear cells resembling Hodgkin (H) or Sternberg-Reed (SR) cells. This cell line is tumorigenous after injection of as few as 10(4) lymphoma cells into nude or immunocompetent C57Bl/6 mice and leads to death from progressive disease of all treated animals within a few weeks. The histological analysis of these tumors revealed a diffuse large cell malignant lymphoma that is morphologically almost identical to human anaplastic large cell lymphoma (ALCL). The lymphoma cells did not show overexpression of the anaplastic lymphoma kinase (ALK) gene, which is found in about 50% of the cases of human ALCL. Thus, this model may be an animal model for an important subset of human ALCL. The cytokine profile, which is of the T helper 2 type, showed strong parallels to the human lymphoma counterpart. Mice suffering from such lymphomas could not be cured with a regimen using high dose cyclophosphamide similar to many ALCL patients. Such an animal model for ALCL has not yet been recognized, but may provide the basis for investigating new antitumor immunotherapies in a fully immunocompetent host.

[New immunotherapeutic approaches for the treatment of anaplastic large cell lymphoma in a mouse model]. / Neue immuntherapeutische Ansätze des grosszelligen anaplastischen Lymphoms in einem Maus-Modell.

As there is still a high mortality of the large cell anaplastic non Hodgkin lymphoma (ALCL) (between 40-70%, depending on prognostic factors) there is a need for new therapeutic approaches. Therefore, we studied different strategies for cancer immunotherapy in an immunogenic ALCL tumor model system: A murine IL-9 dependent T cell line was transfected with IL-9 cDNA, resulting in an autonomous growing T cell line designated G6BB, which had a high tumor incidence after injecting of as few as 10(4) cells subcutaneously into syngeneic C57Bl/6 mice. Tumor growth, dissemination, histology, and immunohistochemistry were similar to human ALCL. This mouse model provides an immunogenic in vivo system to investigate antitumor immunotherapies. In order to increase antigen recognition by T cells and T cell activation, we administered tumor bearing mice cell-based cancer vaccines with irradiated tumor cells alone or in combination with immunostimulating CpG-Oligonucleotides, a combination of Th1 cytokines and Th2 cytokine antibodies (IL-12, IFN-gamma, GM-CSF, Anti-IL-10) (after detecting a Th2 cytokine profile in G6BB), or the recall antigens diphtheria, pertussis, and tetanus.