Tumor cells polysaccharides

Belkin et al. 29> were first to examine various polysaccharide fractions from higher plants for their antitumor activity. They could demonstrate that many of these fractions produced haemorrhagic necrosis in different tumor types. In most cases, the polysaccharides were injected intraperitoneally into mice carrying Sarkoma 37 ascites tumor. The result was a progressive increase in cell volume and in cytoplasmic vacuolization. Osswald 30) found that tragacanth, gum arabic, and CMC reduced tumor cells in Ehrlich ascites carcinoma in female NMRE mice. The effect depended upon the dose, the route of injection, and the molecular size of the polysaccharides administered. 

The most likely effect of polysaccharides upon tumor cells might be related to the immune response. 

Polymeric prodrugs are currently one of the most investigated topics. This research has resulted in breakthrough therapeutics, and many compounds are under clinical development (Table 3.7). Other examples of polymeric prodrug applications include the use of polysaccharides such as dextran, mannan, and pullulan to enable active targeting to tumor cells.117... 

Polysaccharides and generally carbohydrates represent the main carbon sink in the plant cell. Polysaccharides commonly serve nutritional (e.g., starch) and structural (e.g., cellulose) functions in plants. Some polysaccharides are cytotoxic against certain types of cancer, such as mouse skin cancer, or tumor lines in vitro (e.g., mouse Sarcoma-180). However, most polysaccharides exert their action through stimulation of the immune system (cancer immunotherapy). Plants containing polysaccharides with anticancer properties include the following ... 

The nature of the antitumor action of a polysaccharide is not entirely clear, but certain bacterial polysaccharides may directly attack tumors, as evidenced by the resulting intratumoral hemorrhage and necrosis. On the other hand, most of the polysaccharides from other botanical sources cannot be shown to exert any direct action on tumor cells. Their antitumor action must, therefore, be considered to be dependent upon the reaction of the host that is, their effect is host-mediated. It is possible that, in some instances, these two types of action may be interwoven. The discussion in this Section covers only those polysaccharides that effect a host-mediated reaction. 

Several workers have reported that bacterial, antitumor agents cannot have a direct effect on tumor cells, as the bacterial polysaccharide-preparations that produced hemorrhage and necrosis in solid tumors had no effect on tumor cells in vitro208 or in tissue culture.209,210 Seligman and coworkers211 found that only a small propor-... 

The polysaccharide molecules, or some portion of them, could stimulate an organ or organ system (for example, the adrenal, liver, or reticuloendothelial system), which then secretes a substance, probably very much different from the polysaccharide, which acts on the tumor cells. However, Belkin and coworkers29 found that the polysaccharides from golden rod, hydrangea, or clover do not stimulate the reticuloendothelial system. 

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