Heat induced expression of CD95 and its correlation with the activation of apoptosis upon heat shock in rat histiocytic tumor cells

The heat shock response is a universal phenomenon and is among the most highly conserved cellular responses. However, BC-8, a rat histiocytoma, fails to mount a heat shock response unlike all other eukaryotic cells. In the absence of induction of heat shock proteins, apoptotic cell death is activated in BC-8 tumor cells upon heat shock. We demonstrate here that stable transformants of BC-8 tumor cells transfected with hsp70 cDNA constitutively express hsp70 protein and are transiently protected from heat induced apoptosis for 6-8 h. In addition heat stress induces CD95 gene expression in these tumor cells. There is a delay in CD95 expression in hsp70 transfected cells suggesting a correlation between the cell surface expression of CD95 and the time of induction of apoptosis in this tumor cell line. Also expression of CD95 antigen appears to inhibit the interaction between heat shock factors and heat shock elements in these cells resulting in the lack of heat shock response.     

Production of antiviral and antitumor proteins MAP30 and GAP31 in cucurbits using the plant virus vector ZYMV-AGII

ZYMV-AGII (zucchini yellow mosaic virus-AGII) is a recombinant nonpathogenic potyvirus-based vector system for the expression of foreign genes in cucurbit plants and their edible fruits, including squash, cucumber, melon, watermelon, and pumpkin. MAP30 (Momordica anti-HIV protein, 30 kDa) and GAP31 (Gelonium anti-HIV protein 31 kDa) are multifunctional plant proteins with activity against HIV-1 virus. These proteins are also effective against other viruses, tumor cells, and microbes. We report here the production and characterization of biologically active MAP30 and GAP31 in squash plant by expression of their genes using the ZYMV-AGII vector. Recombinant expressed MAP30 and GAP31 exhibit comparable antiviral, antitumor, and antimicrobial activities as their counterparts from their original plant sources, with EC(50)s in the ranges of 0.2-0.3 nM for HIV-1. These results demonstrate for the first time the amplification and production of therapeutic proteins, MAP30 and GAP31, in common vegetables. This provides valuable alternative food sources of these antiviral, antitumor, and antimicrobial agents for therapeutic applications.