Interferons antitumour effect

Since plants used as herb medicines contain high amounts of germanium compounds, the latter have been regarded as having immunopotentiation and antitumour activities. At present, organogermanium compounds are mainly used for medical applications. For example, Ge-132 is well known to have not only an antitumour effect, but also to induce interferon (IFN) production in vivo8. 

Mattson K, Niiranen A, Pyrhonen S, Farkkila M, Cantell K. Recombinant interferon gamma treatment in non-small cell lung cancer. Antitumour effect and cardio-toxicity. Acta Oncol 1991 30(5) 607-10. 

Some oligonucleotides do not act by interferon induction but rather by inhibition of proviral DNA synthesis, one of the most active being single stranded poly(A) [32, 33]. In view of the demonstrated activity of the poly(A)—Rh acetate complex in tumour systems [34] and its binding specificity for adenine nucleotides [35] (Section 6.2) the effect of highly specific metal complexes on this type of interaction is of considerable interest. The synthesis of complexes specific for singly stranded DNA, especially those with little antitumour effect, should be significant. 

This purely synthetic polymer was an antitumour agent which was found to stimulate high levels of interferon in animals [127] and in man [128]. Structure (XXIII) for the repeating unit is probably correct being derived from several obviously incorrect descriptions in the literature [129, 130]. Interferon induction could not be demonstrated in vitro with pyran copolymer, but only in intact animals. Similar effects were shown to occur with a large variety of polyanionic polymers based on maleic acid or acrylic acid [129]. Variation of inducing ability with molecular weight of these polymers showed that optimum size was 17000-34000 [131],... 

Two polysaccharides from shiitake can suppress tumours in experimental trials. Lentinan is a high My (1000000) P-1,3 glucan, with no peptide. It has pronounced antitumour activities in animals and is a potent interferon inducer in animals when administered intravenously however, oral administration did not suppress tumour growth in animals. KS-2, containing mannose as the main component and a small amount of peptide, demonstrated effective suppression of tumour growth in vivo by oral or intraperitoneal administration. Studies indicate strong macrophage activation—this is associated with induction of interferon (Fuji et al. 1978). 

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