Binding of galectin-1 to breast cancer cells MCF7 induces apoptosis and inhibition of proliferation in vitro in a 2D- and 3D- cell culture model.

BACKGROUND: Galectin-1 (gal-1) belongs to the family of ß-galactoside-binding proteins which primarily recognizes the Galß1-4GlcNAc sequences of oligosaccharides associated with several cell surface glycoconjugates. The lectin recognizes correspondent glycoepitopes on human breast cancer cells. Galectin-1 is expressed both in normal and malignant tissues. Lymphatic organs naturally possessing high rates of apoptotic cells, express high levels of Galectin-1. Furthermore galectin-1 can initiate T cell apoptosis. Binding of galectin-1 to trophoblast tumor cells presenting the oncofetal Thomsen-Friedenreich (TF) carbohydrate antigen inhibits tumor cell proliferation. In this study we examined the impact galectin-1 has in vitro on cell proliferation, apoptotic potential and metabolic activity of MCF-7 and T-47D breast cancer cells in dependence to their expression of the Thomsen-Friedenreich (TF) tumor antigen. METHODS: For proliferation and apoptosis assays cells were grown in presence of 10, 30 and 60 µg gal-1/ml medium. Cell proliferation was determined by a BrdU uptake ELISA. Detection of apoptotic cells was done by M30 cyto death staining, in situ nick translation and by a nucleosome ELISA method. Furthermore we studied the impact galectin-1 has on the metabolic activity of MCF-7 and T-47D cells in a homotypic three-dimensional spheroid cell culture model mimicking a micro tumour environment. RESULTS: Gal-1 inhibited proliferation of MCF-7 cells (strong expression of the TF epitope) but did not significantly change proliferation of T-47D cells (weak expression of the TF epitope). The incubation of MCF-7 cells with gal-1 raised number of apoptotic cells significantly. Treating the spheroids with 30 µg/ml galectin-1 in addition to standard chemotherapeutic regimes (FEC, TAC) resulted in further suppression of the metabolic activity in MCF-7 cells whereas T-47D cells were not affected. CONCLUSIONS: Our results demonstrate that galectin-1 can inhibit proliferation und metabolic cell activity and induce apoptosis in breast tumor cell lines with high expression levels of the Thomsen-Friedenreich (TF) antigen in monolayer and spheroid cell culture models.

Cervical conisation and the risk of preterm delivery: a retrospective matched pair analysis of a German cohort.

PURPOSE: Since the routine screening program for cervical dysplasia by Pap smear was established in the early 1970s, the rate of cervical cancer has continually dropped. Even if a high percentage of cervical dysplasia shows spontaneous restitution, the only effective therapy for persisting cervical dysplasia is local ablation or excision which might be associated with an increased risk of preterm delivery in subsequent pregnancies. However, data from German patients are missing, so the aim of this study was to evaluate the risk of preterm delivery and associated risks in a cohort of patients who had undergone cervical conisation previous to their pregnancies. METHODS: A total of 144 patients with conisation and subsequent pregnancy were identified. They were compared regarding week of delivery and preterm birth, fetal birth weight, fetal outcome and birth procedure (spontaneous delivery, vacuum extraction, primary and secondary cesarean section) with their matched partners. RESULTS: 135 patients with singleton pregnancies and their matched partners were evaluated in the final analysis. The mean age was 33.5 years. Comparing the case and control group we reached significant different results for week of delivery, but not preterm birth defined as birth prior to 37 weeks of gestation. CONCLUSIONS: Within this German cohort cervical conisation did not increase the risk for preterm birth, cesarean section or poor fetal outcome. We therefore conclude that cervical conisation is an appropriate method to treat women with cervical dysplasia also at childbearing age when prevention of cervical cancer is needed.

Tumor suppressor KAI1 affects integrin alphavbeta3-mediated ovarian cancer cell adhesion, motility, and proliferation.

The tetraspanin KAI1 had been described as a metastasis suppressor in many different cancer types, a function for which associations of KAI1 with adhesion and signaling receptors of the integrin superfamily likely play a role. In ovarian cancer, integrin alphavbeta3 correlates with tumor progression and its elevation in vitro provoked enhanced cell adhesion accompanied by significant increases in cell motility and proliferation in the presence of its major ligand vitronectin. In the present study, we characterized integrin alphavbeta3-mediated tumor biological effects as a function of cellular KAI1 restoration and proved for the first time that KAI1, besides its already known physical crosstalk with beta1-integrins, also colocalizes with integrin alphavbeta3. Functionally, elevated KAI1 levels drastically increased integrin alphavbeta3/vitronectin-dependent ovarian cancer cell adhesion. Since an intermediate level of cell adhesive strength is required for optimal cell migration, we next studied ovarian cancer cell motility as a function of KAI1 restoration. By time lapse video microscopy, we found impaired integrin alphavbeta3/vitronectin-mediated cell migration most probably due to strongly enhanced cellular immobilization onto the adhesion-supporting matrix. Moreover, KAI1 reexpression significantly diminished cell proliferation. These data strongly indicate that KAI1 may suppress ovarian cancer progression by inhibiting integrin alphavbeta3/vitronectin-provoked tumor cell motility and proliferation as important hallmarks of the oncogenic process.