Sensitization of HER2 Positive Breast Cancer Cells to Lapatinib Using Plants-Derived Isothiocyanates.

Nearly 25% of all breast cancer is characterized by overexpression of HER2 (human epidermal growth factor receptor 2) which leads to overactivation of prosurvival signal transduction pathways, especially through Akt-mTOR-S6K kinases, and results in enhanced proliferation, migration, induction of angiogenesis, and apoptosis inhibition. Anti-HER2 targeted therapies, such as specific monoclonal antibodies or small-molecule tyrosine kinase inhibitors, even in combination, still seem to be insufficient due to incidence of primary or acquired resistance and prevalence of serious side-effects of these drugs. We assumed that combination of compounds that target different levels of the above-mentioned signal transduction pathway might be more effective in eradication of breast cancer cells. In our in vitro research we used a commercially available drug, lapatinib, acting at the level of the receptor in combination with 1 of the plant-derived isothiocyanates: sulforaphane, erucin, or sulforaphene, as it has been shown previously that sulforaphane inhibits Akt-mTOR-S6K1 pathway in breast cancer cells. We used 2 HER2 overexpressing breast cancer cell lines, SKBR-3 and BT-474. Combinations of the drug and isothiocyanates considerably decreased their viability. This action was synergistic and was accompanied by a decrease in phosphorylation of HER2, Akt, and S6. Combined treatment induced apoptosis more efficiently than either agent alone; however the most effective was a combination of lapatinib with erucin. These findings might support the optimization of therapy based on lapatinib treatment.

Retrospective Evaluation of Thromboembolism Risk in Ovarian Cancer Patients Treated with Bevacizumab.

BACKGROUND: Bevacizumab is used in addition to standard, platinum-based chemotherapy to treat advanced-stage ovarian cancer patients. Thrombosis is a well-documented adverse effect of bevacizumab. OBJECTIVE: The aim of this study was to identify predictive parameters for thromboembolic events in ovarian cancer patients and to explain how bevacizumab increases the risk of these events. PATIENTS AND METHODS: Fifty-seven FIGO stage III ovarian cancer patients who underwent cytoreductive surgery and chemotherapy were identified and included in this retrospective study. Twenty-six patients were treated with carboplatin and paclitaxel (CP) only (control group), and 31 patients received CP with bevacizumab (study group). The two groups were compared with regard to thrombosis risk factors and laboratory parameters (total leukocytes, platelet count, hemoglobin, APTT, prothrombin time, INR, fibrinogen levels, D-dimer concentration) before treatment, after each course of chemotherapy, and during thromboembolic events. RESULTS: Only patients in the group receiving bevacizumab experienced venous thromboembolism (VTE) (p=0.03, χ² test). VTE occurred on average at the 13th cycle of chemotherapy. Patients who experienced VTE had increased BMI before chemotherapy as compared to patients with no thromboembolic event (27.2 vs. 23.3, p=0.005, Mann-Whitney test). D-dimer concentration before treatment was also elevated more in patients affected by VTE (3132.5) than in the non-VTE group (956.43) (p=0.0007, Mann-Whitney test). During the first four administrations of chemotherapy in patients with future VTE, there was a reduction in D-dimer concentration and an extension of APTT. A D-Dimer level higher than 485 ng/mL prior to first chemotherapy indicates for a risk of VTE with 94% sensitivity and 36% specificity. CONCLUSIONS: An elevated D-dimer level and high BMI before chemotherapy are risk factors for VTE in ovarian cancer patients receiving bevacizumab. Bevacizumab possibly increases the risk for VTE.

Rhinanthus serotinus (Schönheit) Oborny (Scrophulariaceae): immunohistochemical and ultrastructural studies of endosperm chalazal haustorium development.

Chalazal endosperm haustorium in Rhinanthus serotinus consists of a single large binucleate cell. It originates from the primary endosperm cell dividing transversely into two unequal cells: a smaller micropylar cell and a larger chalazal cell. The chalazal cell undergoes a single mitotic division, then lengthens significantly during development and functions as a chalazal endosperm haustorium. In this paper, immunofluorescent techniques, rhodamine phalloidin assay, and electron microscopy were used to examine the actin and tubulin cytoskeleton during the development of the chalazal haustorium. During the differentiation stage, numerous longitudinally oriented bundles of microfilaments ran along the axis of transvacuolar strands in haustorium. Microtubules formed intensely fluorescent areas near the nuclear envelope and also formed radial perinuclear microtubule arrays. In the fully differentiated haustorium cell, the actin cytoskeleton formed dense clusters of microfilaments on the chalazal and micropylar poles of the haustorium. Numerous microfilament bundles occurred near wall ingrowths on the chalazal wall. There were numerous clusters of microfilaments and microtubules around the huge lobed polytenic haustorial nuclei. The microfilaments were oriented longitudinally to the long axis of the haustorium cell and surrounded both nuclei. The microtubules formed radial perinuclear systems which were appeared to radiate from the surface of the nuclear envelope. The early stage of degeneration of the chalazal haustorium was accompanied by the degradation of microtubules and disruption of the parallel orientation of microtubules in the chalazal area of the cell. The degree of vacuolization increased, autophagous vacuoles appeared and the number of vesicles decreased.

Embryogenesis in Sedum acre L.: structural and immunocytochemical aspects of suspensor development.

The changes in the formation of both the actin and the microtubular cytoskeleton during the differentiation of the embryo-suspensor in Sedum acre were studied in comparison with the development of the embryo-proper. The presence and distribution of the cytoskeletal elements were examined ultrastructurally and with the light microscope using immunolabelling and rhodamine-phalloidin staining. At the globular stage of embryo development extensive array of actin filaments is present in the cytoplasm of basal cell, the microfilament bundles generally run parallel to the long axis of basal cell and pass in close to the nucleus. Microtubules form irregular bundles in the cytoplasm of the basal cell. A strongly fluorescent densely packed microtubules are present in the cytoplasmic layer adjacent to the wall separating the basal cell from the first layer of the chalazal suspensor cells. At the heart-stage of embryo development, in the basal cell, extremely dense arrays of actin materials are located near the micropylar and chalazal end of the cell. At this stage of basal cell formation, numerous actin filaments congregate around the nucleus. In the fully differentiated basal cell and micropylar haustorium, the tubulin cytoskeleton forms a dense prominent network composed of numerous cross-linked filaments. In the distal region of the basal cell, a distinct microtubular cytoskeleton with numerous microtubules is observed in the cytoplasmic layer adjacent to the wall, separating the basal cell from the first layer of the chalazal suspensor cells. The role of cytoskeleton during the development of the suspensor in S. acre is discussed.

Are extracellular matrix surface network components involved in signalling and protective function?

Endosperm is an interesting model for in vitro experiments, because of its unique origin, development and ploidy level. Here we used Actinidia deliciosa endosperm-derived callus to investigate morphology, histology and chemistry of extracellular matrix (ECM) structures in morphogenically stable tissue from long-term culture. SEM and TEM analysis showed that ECM is a heterogenous layer which consists of amorphous, dark-staining material, osmiophilic granules and reticulated fibres outside the outer callus cell wall. This structure may serve as a structural marker of morphogenic competence in endosperm-derived callus, because of its presence on the surface of callus forming morphogenic domains and its disappearance during organ growth. Based on immunolabelling, histochemistry, solvent and enzyme treatments, we suggest that pectins and lipids are components of the ECM layer. These results might indicate protective, water retention and/or cell communication functions for this ECM layer.

Distribution of pectin and arabinogalactan protein epitopes during organogenesis from androgenic callus of wheat.

The distribution of several arabinogalactan protein and pectic epitopes were studied during organogenesis in androgenic callus of wheat. In cell wall of mature and degenerating parenchyma cells, the arabinogalactan epitopes JIM4, JIM14, JIM16 or LM2 were expressed differently according to the cells location. LM2 was observed also in meristematic cells of regenerated shoot buds and leaves. Anti-pectin JIM7 labelled the wall of meristematic cells but fluorescence was strongest in outer walls of surface cells of callus and shoot buds coated by extracellular matrix surface network (ECMSN). During leaves growth the ECMSN disappeared, and JIM7 fluorescence decreased. JIM5 epitope was abundant in the cell walls lining the intercellular spaces of callus parenchyma and in tricellular junctions within regenerated buds and leaves.