Characterization of gangliosides from Ehrlich ascites tumour cells and their variants

Tissue inhibitor of metalloproteinases-1 (TIMP-1) inhibits tumor growth and angiogenesis in the TIMP-1 transgenic mouse model

The tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) has been recognized as a multifunctional protein. The role of TIMPs in cancer remains the subject of conflicting reports with an antitumor activity or a tumor growth stimulation activity by several mechanisms. The aim of our study is to investigate the effect of ectopic TIMP-1 overexpression on the primary transplanted tumor growth. We employed transgenic mice overexpressing the human TIMP-1 (hTIMP-1) in the liver under control of the albumin promoter/enhancer (TIMP-Tg-mice) and producing high serum levels of TIMP-1. We used the transplantable Ehrlich tumor cells in the current study. The allograft study revealed that the tumor growth in the TIMP-Tg-mice was more significantly inhibited than control (Cont) mice by associated suppression of neovascularization in the tumor. The in vitro studies showed that the recombinant TIMP-1 (rTIMP-1) did not affect the proliferation of the endothelial cells (ECs) and tumor cells, suggesting that the tumor suppressive effect of TIMP-1 was not due to cytotoxicity. TIMP-1 significantly inhibited EC tubular formation in vitro. Furthermore, TIMP-1 treatment did not affect the levels of matrix metalloproteinase (MMP)-2 and MMP-9 mRNA in the Ehrlich tumor cells in vitro, although these expressions in the tumor were markedly suppressed in the TIMP-Tg-mice, compared to the Cont-mice at the end of the experiment. These results suggested that the ectopically overexpressed TIMP-1 inhibited the tumor growth by angiogenesis suppression.

Changes in ganglioside contents, plasma sialic acid and cAMP levels in experimental hepatoma in mice

The present study was designed to assess whether changes in glycolipids and cyclic AMP contents might serve as markers for the diagnosis of malignancy in the liver. The experimental model was a transplantable murine hepatoma. Experimental mice were divided into three groups: (1) a therapeutic group, which had been transplanted with hepatoma and treated with the antimetabolism drug 5-fluorouracil (0.2 mg/day i.p.), (2) a control group, which had been transplanted with hepatoma and treated with 0.2 ml 0.9% NaCl/day and (3) a normal group of mice. The ganglioside and cAMP contents in the hepatoma tissue, plasma cAMP, total- and lipid-bound sialic acid levels and red blood cell membrane sialic acid levels were determined. Results showed that the ganglioside content, total and lipid-bound sialic acid levels in the control group were significantly higher than those in the livers of normal mice (p < 0.01) while these respective values in the therapeutic group were significantly lower than those in the control group (p < 0.01). The cAMP levels of tumor tissues and plasma in the control group were lower than those in normal mice. No significant difference in red blood cell membrane sialic acid content was observed between the therapeutic and control groups though levels for both were higher than those in normal mice. These results indicate that ganglioside content and sialic acid levels in hepatoma tissues were significantly elevated, and cAMP levels in hepatoma tissues were significantly decreased during proliferation and abnormal differentiation.