Involvement of TNF-α changes in human cancer development, prevention and palliative care

Abstract

Cancer development and ageing are complex sciences. From the study on the process of rodent carcinogenesis, we identified tumor necrosis factor-α (TNF-α) as an important mediator of cancer development. This paper presents three clinical examples of TNF-α up-regulation: by cord factors of Mycobacterium tuberculosis, such as trehalose 6-monomycolate, as an activator of protein kinase C and by a cord factor like fraction of Microsporum canis obtained in the air inside houses in Thailand, both of which are risk factors in human lung cancer development, and by Helicobacter pylori gene product, H. pylori membrane protein 1 (HP-MP1) in relation to human stomach cancer. The second part of this paper deals with down-regulation of TNF-α by a wide variety of cancer preventive agents. Among the various agents, (−)-epigallocatechin gallate (EGCG) and green tea polyphenols inhibited TNF-α gene expression in the cells induced by tumor promoter, mediated through inhibition of NF-κB activation. Studying growth inhibition of human cancer cell lines by morphine, we found that morphine and the new morphine derivatives KT-90 and KT-87 have anticancer activity mediated through induction of apoptosis, in addition to analgesic action. We conclude that environmental and endogenous factors induce NF-κB activation mediated through expression of inflammatory cytokine genes, such as TNF-α, and that the expression pattern of the genes operates similarly in the aging process.