A NOVEL HUMAN TUMOR-NECROSIS-FACTOR-ALPHA MUTEIN, F4614, INHIBITS IN-VITRO AND IN-VIVO GROWTH OF MURINE AND HUMAN HEPATOMA - IMPLICATION FOR IMMUNOTHERAPY OF HUMAN HEPATOCELLULAR-CARCINOMA

Although treatment for hepatocellular carcinoma (HCC) has recently imp roved, most patients still relapse and die from this disease. The deve lopment of new therapeutic and preventive strategies for HCC is, there fore, required. 12 novel mutant protein (mutein) of human tumor necros is factor alfa (TNF-alpha mutein F4614, (1)SSSRGDSD... V-29 ... L-155) was developed to decrease several adverse effects of TNF-alpha. F4614 is known to lack hypotensive effects of human TNF-alpha without losin g its anti-tumor effect in mice transplanted with Meth-A sarcoma. Our study investigated the anti-tumor effects of F4614 against hepatoma ce lls in vitro and in vivo. F4614 significantly inhibited growth of all four tumor cells in vitro. A murine hepatoma cell line, MH134, when in cubated in the presence of F4614, exhibited upregulation of surface ma jor histocompatibility complex (MHC) class-I, intercellular adhesion m olecule-1 (ICAM-1) and B7-1 molecules, and a decreased proportion of c ells in the G(2)/M phase of the cell cycle. In addition, F4614 induced apoptosis in a significant number of MH134 cells. TNF-alpha and F4614 (5 mu g/mouse daily for 5 days) showed similar anti-tumor activities in syngeneic MH134-bearing mice and heterogeneic PLC/PRF/5-bearing ath ymic nude mice. Intratumoral injection of F4614 or TNF-alpha was more effective than intravenous injection. Immunohistochemical analysis of the tumors treated by F4614 revealed that tumors were surrounded with a large number of Mac-1(+) cells and a small number of CD4(+) and CD8( +) T cells; that suggests that intratumoral injection of F4614 elicite d host immunoreactions. Thus, F4614 may be a new strategy for immunoth erapy of HCC.