A Tumor Inhibitor in Lampteromyces japonica. ∗

Abstract

In the fall of 1958, the senior author working in the laboratory of Dr. Ayao Yamamoto, Institute for Infectious Diseases, University of Tokyo, cooperated with Drs. Yamamoto, Ogata, Komatsu and Nakazama in studying the effect of saline extracts of Lampteromyces japonica (L.J.) on Ehrlich mouse tumors and Sarcoma 180. This work included in vivo and in vitro studies with findings of some anti-tumor activity. Lucas et al.(1,2) have demonstrated tumor inhibition by extracts of the fungus genus Calvatia and Holobasidiomycetes.

It seemed desirable to extend these preliminary observations and to determine the effect of fractions of L.J. on the Ehrlich mouse tumor and on human tumor cells growing in tissue culture.

Materials and methods. The tumor-inhibiting original extract was prepared from dried Lampteromyces japonica, the only species of this basidiomycete. The original samples were collected in Japan in 1959.

Ten g of dried material, ground in a 20-mesh Wiley Mill, were extracted with 100 ml of saline (0.85% NaCl) for 24 hours at 5°C with continuous shaking. The saline extract was then spun at 500 g for 20 minutes. The residue was reextracted with 100 ml of saline. Part of the pooled supernatants was dialyzed at 5°C against running tap water for 48 hours and then against distilled water for 3 hours. This saline extract was designated L.J., original extract. To the remainder of the pooled supernatant at a pH of 5.5–6.0, was added cold (5°C) ethanol to a final concentration of 30%. This was kept at 5°C overnight and then centrifuged at 5000 g for 30 minutes in an anglehead centrifuge. The 30% alcohol precipitate was dialyzed and lyophilized. This was designated as fraction No. 2. To the 30% ethanol supernatant, cold ethanol was added to a final concentration of 70%, then kept overnight at 5°C. This material was then centrifuged at 5000 g for 30 minutes and the supernatant was decanted, dialyzed and lyophilized, as was the precipitate.