Interferons in oncology: current status and future directions

Characterisation and properties of a small cell lung cancer cell line and xenograft WX322 with marked sensitivity to alpha-interferon

Controversy exists as to whether interferons usefully influence the growth of epithelial carcinomas. A small cell lung carcinoma (SCLC) cell line, WX322, has been derived which is greater than 1000-fold more sensitive to alpha-interferon (IFN) when grown in agar than other reported SCLC cell lines. The WX322 line has been characterised to prove its epithelial origin and its chemosensitivity compared with that of the NCI-H69 small cell line. The WX322 cell line expresses neuroendocrine and epithelial markers and possesses a morphology consistent with SCLC origin. A concentration of 5 IU ml-1 of IFN produced 50% inhibition of colony formation in agar in the WX322 line, whereas a concentration of greater than 10(5) IU ml-1 was required to produce a comparable effect with the NCI-H69 cell line. In contrast, WX322, possessed similar sensitivity to NCI-H69 cells when exposed to a range of cytotoxic agents. Analysis of the cell cycle indicated that IFN increased the percentage of cells in the G0/G1 phase for the WX322 cell line but increased the percentage in S phase for the NCI-H69 line. Growth of the xenograft, from which the cell line was derived, was also inhibited by IFN at doses greater than 10(5) IU/mouse/day. The WX322 cell line whether grown in agar or as a xenograft shows an unusually high sensitivity to IFN and provides an interesting model for studying mechanisms of IFN cytotoxicity to epithelial cells.

Effect of germanium on 1,2-dimethylhydrazine-induced intestinal cancer in rats

Through recent research, the trace element, germanium, was found to have an anticancer effect. The purpose of this research was to determine the effect of germanium on 1,2-dimethylhydrazine-induced intestinal cancer in rats. Ninety-six 8-week-old Sprague-Dawley male rats were divided into 4 groups, with 24 rats in each group. All received dimethylhydrazine, 20 mg/kg body weight, subcutaneously, once a week for 20 weeks. Except for one control group, the other three groups were subdivided into six groups and administered three different kinds of germanium (inorganic germanium, organic germanium, and natural organic germanium) one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment, respectively. Twenty-four weeks after carcinogen exposure, all surviving animals were sacrificed and examined for intestinal tumors. The number and location of the tumors were recorded and the pathology examined. The incidence of intestinal cancer in the control group (dimethylhydrazine only) was 91 percent; in groups provided with inorganic germanium one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only, it was 91 and 78 percent; in groups provided with organic germanium one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only, it was 64 and 64 percent; in groups provided with natural organic germanium one month before and during dimethylhydrazine treatment and during dimethylhydrazine treatment only, it was 50 and 45 percent. From these results, the authors conclude that natural organic germanium has the best prevention effect for intestinal cancer in this animal model (P less than 0.01), followed by organic germanium (P less than 0.05). Inorganic germanium has no effect. However, there is no difference in the cancer prevention effect of germanium provided one month before and during dimethylhydrazine treatment, and during dimethylhydrazine treatment only.