Bevacizumab, an anti-vascular endothelial growth factor (VEGF-A) antibody, is used in metastatic colorectal carcinoma (CRC) treatment, but responses are unpredictable. Vascular endothelial growth factor is alternatively spliced to form proangiogenic VEGF 165 and antiangiogenic VEGF 165 b. Using isoform-specific enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, we found that over 90% of the VEGF in normal colonic tissue was VEGF xxx b, but there was a variable upregulation of VEGF xxx and downregulation of VEGF xxx b in paired human CRC samples. Furthermore, cultured colonic adenoma cells expressed predominantly VEGF xxx b, whereas colonic carcinoma cells expressed predominantly VEGF xxx . However, adenoma cells exposed to hypoxia switched their expression from predominantly VEGF xxx b to predominantly VEGF xxx . VEGF 165 b overexpression in LS174t colon cancer cells inhibited colon carcinoma growth in mouse xenograft models. Western blotting and surface plasmon resonance showed that VEGF 165 b bound to bevacizumab with similar affinity as VEGF 165 . However, although bevacizumab effectively inhibited the rapid growth of colon carcinomas expressing VEGF 165 , it did not affect the slower growth of tumours from colonic carcinoma cells expressing VEGF 165 b. Both bevacizumab and anti-VEGF 165 b-specific antibodies were cytotoxic to colonic epithelial cells, but less so to colonic carcinoma cells. These results show that the balance of antiangiogenic to proangiogenic isoforms switches to a variable extent in CRC, regulates tumour growth rates and affects the sensitivity of tumours to bevacizumab by competitive binding. Together with the identification of an autocrine cytoprotective role for VEGF 165 b in colonic epithelial cells, these results indicate that bevacizumab treatment of human CRC may depend upon this balance of VEGF isoforms.

Abstract. In situ hybridization is used to survey the tissue-specific and developmental expression of the cloned mouse gene Sparc, coding for a protein homologous to the bovine Ca++-binding protein, osteonectin. High levels of SPARC RNA are found in osteoblasts and odontoblasts. In addition, high grain counts are associated with a variety of other cell types in the embryo and newborn mouse, including parietal endoderm, deciduum, whisker follicles (connective tissue sheath), peripheral nerve trunk, skin (dermis), and stomach (submucosa). Spatially restricted but high levels of SPARC mRNA are also seen in the adult adrenal glands, testis, and ovary. This pattern of differential gene expression demands a reassessment of the function originally proposed for osteonectin, and predicts a much wider role for the protein in a variety of biological processes.

Malignant melanoma (MM), the most common cause of skin cancer deaths, metastasises to regional lymph nodes. In animal models of other cancers, lymphatic growth is associated with metastasis. To assess if lymphatic density (LD) was increased in human MM, and its association with metastasis, we measured LD inside and around archival MM samples (MM, n ¼ 21), and compared them with normal dermis (n ¼ 11), basal cell carcinoma (BCC, n ¼ 6) and Merkel cell carcinoma (MCC), a skin tumour thought to metastasise through a vascular route (MCC, n ¼ 6). Lymphatic capillary density (mm À2 ), as determined by immunohistochemical staining with the lymphatic specific marker LYVE-1, was significantly increased around MM (10.072.5 mm À2 ) compared with normal dermis (2.470.9 mm À2 ), BCC (3.070.9 mm À2 ) and MCC (2.471.4 mm À2 ) (Po0.0001). There was a small decrease in LD inside MM (1.170.7 mm À2 ) compared with normal dermis, but a highly significant decrease in BCC (0.1470.13) and MCC (0.1272.4) (Po0.01 Kruskal -Wallis). Astonishingly, LD discriminated between melanomas that subsequently metastasised (12.871.6 mm À2 ) and those that did not (5.471.1 mm À2 , Po0.01, Mann -Whitney). Lymphatic invasion by tumour cells was seen mainly in MM that metastasised (70% compared with 12% not metastasising, Po0.05 Fisher's Exact test). The results show that LD was increased around MMs, and that LD and tumour cell invasion of lymphatics may help to predict metastasis. To this end, a prognostic index was calculated using LD, lymphatic invasion and thickness that clearly discriminated metastatic from nonmetastatic tumours.

Systemic treatment of diabetic rats with a novel human growth factor, vascular endothelial growth factor (VEGF)-A165b, reversed neuropathic pain and peripheral nerve damage.

These results indicate that changes in the bioavailability of VEGF-A sourced from ATII cells, namely the ratio of VEGF-Aa to VEGF-Ab, are critical in development of pulmonary fibrosis and may be a paradigm for the regulation of tissue repair.