CORELATION BETWEEN HEPATIC SINUSOIDAL ENDOTHELIAL CELLS AND HUMAN COLORECTAL CARCINOMA CELLS IN LIVER METASTASIS

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 09671218
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General surgery
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: SUGIHARA Kenichi Tokyo Medical and Dental University, 2nd Dept. of Surg., Professor, 医学部, 教授 (10171167)
• Co-Investigator(Kenkyū-buntansha): YOSHINAGA Keigo Tokyo Medical and Dental University, 2nd Dept. of Surg., assistant Professor, 医学部, 講師 (80240745)
• Project Period (FY): 1997 – 1999
• Keywords: LIVER / METASTASIS / CARCINOMA

Research Abstract

The liver is the major site for metastasis by colorectal carcinoma (CRC) and may have different mechanisms that inhibit CRC growth. We have used a tumor cell-sinusoidal endothelial cell (SEC) coculture system to evaluate whether SEC are cytotoxic to weakly or highly metastatic CRC cells. SEC were isolated from the livers of normal Swiss mice by a portal vein enzymatic infusion method and established as monolayers in 96 well microtiter plates. Confluent SEC monolayers contained 93% endothelial cells (by low density lipoprotein (LDL) receptor staining) and 7% Kupffer cells. When CRC cells were prelabeled with the vital fluorescent dyes rhodamine-dextran and calcein AM and then cocultured with confluent SEC monolayers to assess viability, the % metabolic activity of Clone A cells, a weakly metastatic CRC, was significantly lower than that of CX-1 cells, a highly metastatic CRC, after 4 hrs of coculture (p<0.05). Pretreatment of SEC gadolinium chloride (GaClィイD23ィエD2), an inhibitor of Kupffer cell function, did not block the effect of SEC on Clone A cell. After 24 hrs of coculture with Clone A, SEC produced 114±5.0 nM nitrite vs 123±5.0 and 8±2.0 for SEC and Clone A cells cultured alone, respectively. Furthermore, when 10ィイD1-6ィエD1 to 1 mM NィイD1GィエD1-methyl-L-arginine (NMMA) was added to SEC and Clone A cocultures, toxicity to Clone A cells was blocked as nitrite production was inhibited by dose greater than 10ィイD1-2ィエD1 mM. Unstimulated murine SEC are more toxic to the weakly metastatic Clone A cells than highly metastatic CX-1 cells. Thus, hepatic SEC may be a major host effector cell population that eliminates weakly metastatic CRC through the production of nitric oxide.