Expression of VEGFxxxb, the inhibitory isoforms of VEGF, in malignant melanoma

Malignant melanoma is the most lethal of the skin cancers and the UK incidence is rising faster than that of any other cancer. Angiogenesis – the growth of new vessels from preexisting vasculature – is an absolute requirement for tumour survival and progression beyond a few hundred microns in diameter. We previously described a class of anti-angiogenic isoforms of VEGF, VEGFxxxb, that inhibit tumour growth in animal models, and are downregulated in some cancers, but have not been investigated in melanoma. To determine whether VEGFxxxb expression was altered in melanoma, PCR and immunohistochemistry of archived human tumour samples were used. In normal epidermis and in a proportion of melanoma samples, VEGFxxxb staining was seen. Some melanomas had much weaker staining. Subsequent examination revealed that expression was significantly reduced in primary melanoma samples (both horizontal and vertical growth phases) from patients who subsequently developed tumour metastasis compared with those who did not (analysis of variance (ANOVA) P<0.001 metastatic vs nonmetastatic), irrespective of tumour thickness, while the surrounding epidermis showed no difference in expression. Staining for total VEGF expression showed staining in metastatic and nonmetastatic melanomas, and normal epidermis. An absence of VEGFxxxb expression appears to predict metastatic spread in patients with primary melanoma. These results suggest that there is a switch in splicing as part of the metastatic process, from anti-angiogenic to pro-angiogenic VEGF isoforms. This may form part of a wider metastatic splicing phenotype

Structural and optical properties of SbxSey thin films obtained by chemical molecular beam deposition method from Sb and Se precursors

SbxSey thin-films were obtained by chemical-molecular beam deposition (CMBD) on soda-lime glass from Sb and Se precursors. By the precise control of the Sb/Se ratio, Sb2Se3 thin films with stoichiometric composition were successfully obtained. The elemental and phase composition, as well as the crystal structure of SbxSey thin-films, were studied by energy-dispersive X-ray microanalysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The optical bandgap of the films was determined from the absorption spectra acquired by a spectrophotometer. The physical properties of SbxSey thin films with different compositions were investigated

Structural and optical properties of {SbxSey} thin films obtained by chemical molecular beam deposition method from Sb and Se precursors

SbxSey thin-films were obtained by chemical-molecular beam deposition (CMBD) on soda-lime glass from Sb and Se precursors. By the precise control of the Sb/Se ratio, Sb2Se3 thin films with stoichiometric composition were successfully obtained. The elemental and phase composition, as well as the crystal structure of SbxSey thin-films, were studied by energy-dispersive X-ray microanalysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The optical bandgap of the films was determined from the absorption spectra acquired by a spectrophotometer. The physical properties of SbxSey thin films with different compositions were investigated

Interruption of tumor dormancy by a transient angiogenic burst within the tumor microenvironment

Tumor growth is currently viewed as a phenomenon associated with neovascularization and sustained production of angiogenic factors, but whether a transient angiogenic switch may trigger tumor growth remains unclear. Here, we report that leukemia cells (MOLT-3) were poorly angiogenic and remained dormant when injected s.c. into immunodeficient mice. However, progressive growth of lymphoid tumors was invariably recorded when irradiated angiogenic cells from Kaposi’s sarcoma (KS-IMM) were locally coinjected with MOLT-3 cells or administered later. The persistence of KS-IMM cells in vivo was tracked by flow cytometry and real-time PCR analysis, and it was limited to a few days, during which angiogenesis was induced and preceded tumor growth. The engraftment of other types of poorly tumorigenic cancer cells was also greatly improved by irradiated KS-IMM cells. Moreover, short-term treatment with angiogenic factors, including basic FGF or VEGF, either given as recombinant factors or delivered by retroviral vectors, also accelerated tumor growth. These findings may emphasize that tumor angiogenesis is a process requiring a higher amount of angiogenic factors for its induction than maintenance