Glucuronidase tumor-activated

In contrast, using enzyme histochemical methods, it was observed that lysosomal (3-glucuronidase was liberated in necrotic tumor areas as functionally active enzyme (75). The cells responsible for the liberation of the enzyme are mainly acute and chronic inflammatory cells, as shown by immunochemistry (74). These observations led to the development of the new concept of prodrug monotherapy (PMT) (74, 75). 

Conchie, S. L., and Bittner, J. J. The effects of mammary tumors on the 111. glucuronidase and esterase activities of a number of mouse strains. 

There are at least three theories as to how the HCN interferes with tumor growth, but all theories relative to the action of nitrilosides recognize the steady low-level supply of HCN as the active agent. The simplest theory postulates that cancer cells do not have rhodanase instead, they are surrounded by another enzyme, beta-glucuronidase, which releases the bound cyanide from the Laetrile at the site of the malignancy. So, Laetrile is believed to attack and destroy only the malignant cells. 

The cliaractcristic ability of malignant tumors to invade adjacent tissues may be related to such factors as tissue pressure, reduced adhesiveness of the cells, and the elaboration of toxic sul>stances, but the demonstration that invasive rather than noninvasivc tumors have raised hyaluronidase, ezo- -A -acetyl-D-hcxosamiiiidas and ezo- -D-glucuronidase activities, suggests that these enzymes could be related to invasiveness (Boyland and McClean, 1935 Carr, 1965). Some supoprt for this comes from a report that specific inhibitors of ezo-j8-A -acetyl-D-hexosaminidase and /3-D-gIucuronidase activities caused regre.ssions of tumors in mice (Conchic and Levvy, 1957 Carr, 1963). 

In normal brain tissue, /3-glucuronidase exists predominantly in the bound or latent form and is distributed with lysosomes and microsomes. Latent activity in 16 human gliomas and metastatic brain tumors is discussed (Dekirmenjian e( al., 1965). 

Homogenates from irradiated mouse mammary tumor showed an increase of total activities of lysosomal enzymes and a shift from sediment le toward unsedimentable activity. These biochemical changes were accompanied by an increase in the value of /S-glucuronidase level in both serum and urine (Watts et d., 1966),... 

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