Enhanced chemoresistance and tumor sphere formation as a laboratory model for peritoneal micrometastasis in epithelial ovarian cancer.

BACKGROUND AND PURPOSE: Ovarian cancers are composed of heterogeneous cell populations, including highly proliferative immature precursors and differentiated cells that may belong to different lineages. The main reason why epithelial ovarian cancer is difficult to treat is the unusual mechanism of dissemination that involves local invasion of pelvic and abdominal organs. But, unlike many other carcinomas, initial dissemination rarely requires blood or lymph vessels. Because it has been proven that aggregates of malignant cells within the ascites of patients diagnosed with ovarian cancer represent an impediment to cure such cancers, in the present study we adopted suspension culture combined with anti-cancer regimens as a laboratory strategy for research of the initial process of peritoneal micrometastasis. EXPERIMENTAL DESIGN: MLS human ovarian cancer cells were cultured in serum-free medium. Cells of passage eight were treated in combination with the anticancer agent doxorubicin at different peak plasma concentrations for 24 hours, and then maintained under suspension culture. The acquired increased aggressiveness properties was confirmed by multidrug resistance assays and by their ability to grow in an anchorage-independent manner in vitro as tumor spheroids. RESULTS: Cells selected after chemotherapy had a increased proliferative potential, eliminated Rhodamine 123 in culture and also formed spheroids in suspension. CONCLUSIONS: Here we present direct evidence that the metastasis of human ovarian cancer may be a result of transformation and dysfunction of immature precursor cells in the ovary. Also, spheroid formation may represent a key component of chemotherapy recurrence and a better understanding of these 3D structures can contribute to the development of new treatments for metastatic carcinoma.

Effects of 60Co gamma-rays on human osteoprogenitor cells.

BACKGROUND: Radiation therapy is one of the most efficient treatments of neoplastic diseases used worldwide. However, patients who undergo radiotherapy may develop side effects that can be life threatening because tissue complications caused by radiation-induced stem cell depletion may result in structural and functional alterations of the surrounding matrix. This treatment also damages the osteogenic activity of human bone marrow by suppressing osteoblasts, leading to post-irradiation sequelae. Even if widely used in oncology, there is still little information on the fate and potential therapeutic efficacy of electromagnetic rays. MATERIAL AND METHODS: We addressed this question using both human mesenchymal stem cells and osteoblasts. Monoclonal antibody characterization identified specific surface markers for stem cells (SSEA-4, CD29, CD105, Oct 3, Nanog and SOX2) and osteoblasts (Osteopontin and Osteonectin). The technique of anti-alkaline phosphatase FITC-staining demonstrated the presence of this specific ectoenzyme. Cells were cultured in complex osteogenic medium (DMEM, 15% fetal calf serum, non-essential amino acids, L-glutamine, dexametazone, ascorbic acid, insulin, TGF-beta, BMP-2 and beta-glycero-phosphate) after being irradiated at 0.5 Gy, 1 Gy, 2 Gy and 4 Gy using a Theratron 1000 60Co source. The viability of irradiated cells was assessed using Trypan Blue staining. The comparison between cell lineages after culture in osteogenic media regarding phenotypical characterization and the intensity of the mineralization process included histology stainings (Alizarin Red S, Alcian Blue and von Kossa), and the MTT-based proliferation assay. RESULTS: After irradiation, the proliferation and differentiation of osteoprogenitor cells is dose-dependent. CONCLUSIONS: This study is one among the first papers investigating the biophysics of low-dose gamma-irradiation on stem cell culture, focusing on the potential applications in radiation oncology and various palliative treatments.

Seroprevalence of Bartonella species, Coxiella burnetii and Toxoplasma gondii among patients with hematological malignancies: A pilot study in Romania.

Patients receiving immunosuppressive cancer treatments in settings where there is a high degree of human-animal interaction may be at increased risk for opportunistic zoonotic infections or reactivation of latent infections. We sought to determine the seroprevalence of selected zoonotic pathogens among patients diagnosed with haematologic malignancies and undergoing chemotherapeutic treatments in Romania, where much of the general population lives and/or works in contact with livestock. A convenience sample of 51 patients with haematologic cancer undergoing chemotherapy at a referral clinic in Cluj-Napoca, Romania, was surveyed regarding animal exposures. Blood samples were obtained and tested for evidence of infection with Bartonella species, Coxiella burnetii and Toxoplasma gondii, which are important opportunistic zoonotic agents in immunocompromised individuals. 58.8% of participants reported living or working on a farm, and living or working on a farm was associated with contact with livestock and other animals. 37.5% of participants were IgG seroreactive against one or more of five Bartonella antigens, and seroreactivity was statistically associated with living on farms. Farm dwellers were 3.6 times more likely to test IgG seroreactive to Bartonella antibodies than non-farm dwellers. 47.1% of the participants tested T. gondii IgG positive and 13.7% tested C. burnetii IgG positive, indicating past or latent infection. C. burnetii IgM antibodies were detected in four participants (7.8%), indicating possible recent infection. These results indicate that a large proportion of patients with haematologic cancer in Romania may be at risk for zoonotic infections or for reactivation of latent zoonotic infections, particularly with respect to Bartonella species. Special attention should be paid to cancer patients' exposure to livestock and companion animals in areas where much of the population lives in rural settings.