Cancer biology tumor viruses

IL-2 has been approved for the heatment of renal cell carcinoma and also has shown good activity in malignant melanoma. Both of these tumors are refractory to chemotherapy. IL-2 has also been used invesdgationally, both alone and in combinadon with LAK cells, with chemotherapy and with other biological response modifier s (BRM s) to d eat a variety of different cancers (e.g., head and neck carcinoma, colorectal cancer, cend al nervous system cancer etc). In addidon to cancer therapy, IL-2 has been used to d eat padents infected with human immunodeficiency virus and it has been used ex vivo to generate antiviral T cells which were reinfused into padents (Lewko and Oldham, 2003 Dorr, 1993). 

The tumors may arise sporadically or in patients with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome.Current experience is too limited to determine their biologic behavior and prognosis however, in one study, the patients were found to have an improved survival rate relative to those with DAs. ° Immunohistochemically, the epithelioid cells are labeled by antibodies to cytokeratins whereas trypsin, chymotrypsin, lipase, chromogranin, and synaptophysin are usually negative. CD3 antibody highlights the presence of numerous intratumoral T lymphocytes. Rare examples also contain Epstein-Barr virus RNA. ... 

Tetradecanoylphorbol 13-acetate (TPA) and other diterpene esters from the plant family Euphorbiaceae are well-known as tumor-promotion agents [85]. Thus, inhibition of the biological effects induced by TPA has been considered as a promising strategy [68]. To date, two short-term cell-based in vitro bioassays using TPA as a tumor-promoter have been developed to evaluate the potential cancer chemopreventive activities of several lignans isolated from Hernandia species, namely, inhibition of Epstein-Barr virus early antigen activation [6] and the inhibition of the transformation of JB6 mouse epidermal cells [7]. 

Ascorbate and Cyclic Nucleotides. Many biological activities are potentiated by hormonal actions that utilize cyclic 3 5 -AMP and cyclic 3 5 -GMP as "second messengers." Lewin (195) has reviewed extensive evidence showing that ascorbate potentiates the formation of cyclic 3 5 -AMP and is concerned in the inhibition of processes that reduce the concentration of both cyclic 3 5 -AMP and cyclic 3 5 -GMP by hydrolyzing them to 5 -AMP and 5 -GMP, respectively. The role of these cyclic nucleotides in cancer is uncertain, but diminished adenyl cyclase activity has been noted in polyoma virus-transformed cells (45), and cyclic 3 5 -AMP has been shown to inhibit cell multiplication in vitro (195) and tumor growth in vivo (130). 

We recently reported the synthesis of polymeric platinum II derivatives of cis-dichlorodiamineplatinum II, cis-DDP (2 1,2). These polyamines (2) exhibit good inhibition towards a wide range of tumor cells including L929, WISH and HeLa cell lines with good cell differentiation. Some extend the life of (induced) terminally ill cancerous mice by 50%. Further the polyamines exhibit activity towards virus at concentration levels where the cells are unaffected. Recent biological studies are aimed at evaluation of certain polyamines on inhibiting select tumors and viruses for specific disease control. 

A second type of biological hazard involves research with viruses which have the capability of inducing the formation of tumors or cancers in the host organism they may infect. These viruses, called oncogenic viruses, are not included in the class of etiological agents because they differ from the latter in the following ways ... 

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