An electron-microscope study of the effects of lysolecithin on BP8 ascites-tumour cells and phagocytes of mice, compared with the effects of a specific anti-tumour serum plus complement

Hexadecylphosphocholine: preclinical and the first clinical results of a new antitumor drug

Dose-response studies on cytotoxic alkyl lysophospholipids with various chemical structures revealed that a long alkyl chain and a polar group are essential for antitumor activity. The combination of both the long alkyl chain and a phosphocholine group thus results in alkyl phosphocholines. Preclinical studies with hexadecylphosphocholine (He-PC) as a representative compound indicate distinct antineoplastic activity on leukemia cells of human origin. He-PC is highly effective in inhibiting the growth of chemically induced rat mammary carcinomas. Even more striking is the fact that a high percentage of the tumors regressed completely. In a clinical phase I trial on breast cancer patients with local recurrences, topically applied He-PC resulted in regression of skin metastases. A phase II trial for topical treatment and a phase I trial for orally applied He-PC have been initiated to further evaluate the antitumoral activity of this new compound.

Membrane damage in leukemic cells induced by ether and ester lipids: an electron microscopic study

This paper reports a scanning electron microscopy (SEM) study of different leukemic cell lines exposed to 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OMe). This is an ether lipid analog of platelet activating factor (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine) which inhibits neoplastic cell growth in vitro and in vivo and is believed to exert its action through an interaction with the plasma membrane. In this paper evidence of the morphological alteration of leukemic cell membranes due to the exposure to varying concentrations of ET-18-OMe in vitro and in vivo is presented. This membrane damage consists of formation of blebs and holes, and the severity of these two phenomena correlate with the degree of cell viability loss. These alterations were analyzed in comparison to those induced by the known and structurally related permeabilizing agent, lysophosphatidylcholine, an ester lipid.

The effect of withaferin A, a natural steroidal lactone, on the fine structure of S-180 tumor cells

Mouse sarcoma 180 (S-180) solid and ascites tumor cells were treated in vivo and in vitro with withaferin A and observed with the electron microscope. The compound was found to effect this spindle microtubules of cells in metaphase. An interesting finding was the double membranes surrounding the chromosomes in the treated cells; probably the nuclei were reconstructed directly from the metaphase stage in the in vivo withaferin A-treated cells. In addition the membranes of the cells in interphase were affected by in vivo or in vitro treatment with the compound.

The effect of withaferin A on human peripheral blood lymphocytes. An electron-microscope study

Cultures of normal human peripheral blood lymphocytes stimulated by phytohaemagglutinin (PHA) were treated with withaferin A and examined by an electron microscope. The compound was found to affect the spindle microtubules of cells in metaphase. There were no intact pole-to-pole microtubules or pole-to-kinetochore microtubules found in the treated cells; the centrioles were located in the center. Furthermore, cells at interphase were also affected, the membrane system of the cells being damaged.