H. Morinaga et al., AN IN-VIVO STUDY OF HEPATIC AND SPLENIC INTERLEUKIN-1-BETA MESSENGER-RNA EXPRESSION FOLLOWING ORAL PSK OR LEM ADMINISTRATION, Japanese journal of cancer research, 85(12), 1994, pp. 1298-1303
The effects of orally administered biological response modifiers (BRMs
) in preventing postoperative micro liver metastasis of primary colore
ctal cancer were examined in experimental animals. The two BRMs tested
were Krestin (PSK) and Lentinus edodes mycelia (LEM). In previous exp
eriments, we found that oral administration of PSK or LEM suppressed l
iver metastasis and prolonged the survival period. We also found that
these agents elevated the liver natural killer (NK) and liver macropha
ge activities. In the present study in vivo, using reverse transcripta
se-polymerase chain reaction (RT-PCR), we examined whether or not the
liver and spleen have cytokines which would induce NK cells and macrop
hages, and whether or not the liver and spleen have cytokines induced
by NK cells or macrophages. We placed emphasis on the examination of i
nterleukin (IL)-1 beta expression in the liver and spleen in vivo. Two
to six hours after oral administration of PSK or LEM (1 g/kg) to mice
, IL-1 beta levels in the liver and spleen rose, and they returned to
their baseline levels 24 h later. These findings suggest two possibili
ties: (1) hepatic IL-1 beta is potentiated by these agents soon after
administration, resulting in activation of liver NIC cells or macropha
ges, or (2) these agents stimulate IL-1 beta production by liver macro
phages, and the produced IL-1 beta activates liver NK cells or liver m
acrophages (Kupffer cells). The results of this in vivo study suggest
that the potentiation of hepatic and splenic IL-1 beta by PSK and LEM
is involved in the early phases of suppression of micro liver metastas
es of colorectal cancer.