Molecular mechanism about lymphogenous metastasis of hepatocarcinoma cellsin mice

AIM To investigate the correlation between lymphogenous metastasis and matr ix metalloproteinases (MMPs) activity and the expression of Fas ligand of t umor cells in lymph nodes. METHODES Fifty-six inbred 615-mice were equally divided Into 2 groups and i noculated with Hca-F and Hca-P cells. Their lymph node metastatic rates wer e examined. Growth fraction of lymphocytes in host lymph nodes was detected by flow cytometry. The Hca-F and Hca-P cells were cultured with extract of lymph node, liver or spleen. The quantity of MMPs in these supernatants wa s examined by zymographic, analysis. The expression of Fas ligand, PCNA, Bc l-2 protein of Hca-F and Hca-P cells in the mice were examined by immunohis tochemistry. The apoptosis signals of macrophages in lymph nobles were obse rved with in situ DNA fragmentation. RESULTS On the 28(th) day post- inoculation, the lymph node metastatic rate of Hca-F was 80% (16/ 20), whereas that of Hca-P was 25% (5/ 20). The grow th fraction of lymphocytes was as follows: in the Hca-F cells, the prolifer ating peak of lymphocytes appeared on the 14(th) day post-inaculation and t hen decreased rapidly, while in Hca-P cells, the peak appeared on the 7(th) day post-inoculation and then kept at a high level. With the extract of ly mph node, the quantity of the MMP-9 activity increased (P <0.01) and active MMP-9 and MMP-2 were produced by both Hca-F and Hca-P tumor cells, which d id not produce MMPs without the extract of lymph node or with the extracts of the liver and spleen. The expression of Fas Ligand of Hca-F cells was st ronger than that of Hca-P cells (P <0.01). The expressions of PCNA and Bcl- 2 protein of Hca-F cells in the tumors of inoculated area were the same as that of Hca-P cells. In situ DNA fragmentation showed that the positive sig nals of macrophages were around Hca-F cells. CONCLUSION Secretion of MMPs which was associated with metastatic ability o f Hca-F and Hca-P tumor cells depends on the environment of lymph nodes. Th e increased expression of Fas ligand protein of Hca-F tumor cells with high lymphogenous metastatic potential in lymph nodes may help tumor cells esca pe from being killed by host lymphocytes.