Low-molecular-weight heparin (reviparin) diminishes tumor cell adhesion and invasion in vitro, and decreases intraperitoneal growth of colonadeno-carcinoma cells in rats after laparoscopy.

BACKGROUND

Metastases, adhesion and invasion of tumor cells involve a cascade of complex phenomena, which potentially can be affected by glycosaminoglycans. We studied the influence of a low-molecular-weight heparin, reviparin, on the intraabdominal tumor growth in rats undergoing laparoscopy. We also studied cytotoxicity, anti-adhesive, and anti-invasive effects of reviparin in vitro using adenocarcinoma cells CC531.

METHODS

In vitro assays: Adhesion of 1 x 10(5) CC531 adenocarcinoma cells onto microtiter plates coated with 10 microg/ml collagen type I or 10 microg/ml Matrigel was studied in the presence of 0.55; 1.10 and 2.76 mg/ml reviparin, and compared to saline. The cytotoxicity of 1 x 10(4) adenocarcinoma cells was studied in a similar assay. Transwell dual chambers with polycarbonate filters coated with 100 microg/cm2 Matrigel were used to investigate the effect of 0.55; 1.10 and 2.76 mg/ml reviparin on the invasion of 1 x 10(5) adenocarcinoma cells/ml. In vivo experiments: CC531 adenocarcinoma cells (5 x 10(6) cells/ml) were intraperitoneally applied to Wistar Albino Glaxo rats (n=150, Harlan, Germany) with a median weight of 278 g. The rats were divided into 15 groups with 10 animals in each group, underwent laparoscopy, and 1 ml saline containing 0, 0.5, 2.0, 4.0, and 10 mg reviparin per kg b.w. was introduced for intraperitoneal lavage or s.c. After 21 days the animals underwent an autopsy, and the tumor weight was determined.

RESULTS

In vitro experiments: We found a highly significant inhibition of tumor cell adhesion and invasion (p<0.001) by all reviparin concentrations used in the assays. There was no effect of reviparin on the viability of cells in the cytoxicity assay. In vivo experiments: We found that application of 4.0 and 10.0 mg/kg b.w., but not 0.5 or 2.0 mg/kg b.w. significantly (p<0.01) decreased the tumor mass compared to controls, receiving only saline. This effect was most pronounced after the combined i.p. and s.c. application, whereas after a sole i.p. application, only the highest dose of 10 mg/kg b.w. caused a significant inhibition of tumor growth.

CONCLUSION

Low-molecular-weight heparin, reviparin, given in combination of i.p. lavage and s.c. injections, significantly diminishes intraabdominal tumor growth of CC531 adenocarcinoma cells in rats undergoing laparoscopy. This may offer additional therapeutic options for patients undergoing laparoscopic cancer surgery.