Treatment of mice bearing a Krebs ascitic tumor by means of a protocol based on radioactive copper (64Cu). I. The "cancer animal": a new concept leading to an effective antitumoral treatment.

Previous experiments have shown that 64Cu transmutation was inefficient to cure mice which had been injected 6 days earlier with 5 x 10(5) Krebs ascitic cells. The experiments were repeated with 64CuCl2 administered only 1 day after the injection of 5 x 10(5) Krebs ascitic cells when no developing tumor existed. The results reported showed that, even in this case, only a delay in death could be observed. These negative results revealed that malignant cells injected 24 hours previously in a mouse (in vivo conditions) differ from a malignant cell suspension in a tube (in vitro conditions) where the lethal effect of 64Cu transmutation was clearly evidenced. We concluded that some kind of collaboration was established between the few accepted malignant cells and the host. Based on this collaboration we introduced a new concept, "the cancer mouse", in which in addition to the malignant cells some cells in the host, even though non - malignant, nonetheless feature a slightly modified functioning: "the cancer functioning". In this view, an efficient antitumor treatment must act at the same time and in a coordinated manner on the malignant cells and on the host cells which now feature "the cancer functioning". In the efficient treatment described (Anticancer Res 9: 947-954, 1989) some compounds (64Cu and thioproline) act against the malignant genomes, and other components (metal ions, amino acids, vitamin D2, thyroxine and chelating substances) act against the functioning of the host cells by taking into account certain characteristics of living systems. This treatment was efficient in curing mice injected 1 or 6 days previously with 5 x 10(5) Krebs ascitic cells.

Treatment of mice bearing a Krebs ascitic tumor by means of a protocol based on radioactive copper (64Cu). III. Efficiency of the anticancer treatment according to the stage of tumor development.

The treatment described previously (Anticancer Res 9:947-954,1989) was efficient when applied on day 1 or 6 after the injection of 5 x 10(5) Krebs ascitic cells in mice. Under our experimental conditions, all the untreated mice died within 12 to 25 days. The experiments described show that the treatment developed, is efficient when applied on day 11 but not on day 16. To understand the difference in the treatment efficiency between these two days, we tested the 64Cu incorporation inside the ascitic cells. It was observed that 64Cu incorporation exists on day 11 but no longer on day 16. On day 16, the inefficiency of the treatment must be correlated with the non-incorporation of 64Cu inside the ascitic cells. As the tumor growth is also arrested on day 16, an irreversible stage is reached. A model was developed to explain the results obtained. In this model, cancer develops in 3 successive stages. In the first stage, the cellular functioning is under the control of the malignant tumor cells and the number of cells with the "cancer functioning" is increasing with time, but decreasing after removal of the malignant tumor; in the second stage, tumor and cancer both develop independently, meaning that the number of cells with the "cancer functioning" will continue to increase after the removal of the malignant tumor; in the third stage, each cell of the organism has the "cancer functioning" and the characteristics of malignancy will by retroaction.

Treatment of mice bearing a Krebs ascitic tumor by means of a protocol based on radioactive copper (64Cu). II. Analysis of the treatment.

A new treatment is proposed for mice bearing a Krebs ascitic tumor targeting on both the malignant cells and the host cells having the "cancer functioning" (cancer cells) (Anticancer Res 9: 941-946 1989). It is shown that the treatment (a) injure specifically via 64Cu transmutation the DNA of the malignant cells and further perform (with thioproline or spermine) a "reverse transformation" on the damage DNA; (b) restore a "noncancer functioning" in the host cells which had become "cancer cells"; this restoration was performed using, at physiological concentrations, natural compounds already present in all cell types such as metal ions, amino acids, vitamin D2, thyroxine and chelating substances. To decrease the damage induced in the organism by the radiation emitted by 64Cu, a radioprotector, glycerol, was used. Two different strains of mice were used (Swiss or CBA). For each of them, the same treatment was efficient on condition that thioproline or spermine was used for Swiss or CBA mice respectively.

[Application of the lethal effect of electron capture decay: attempt to control the growth of an ascitic krebs tumor in mice using 64cu]. / Application de l'effet létal de la capture électronique: essai de contrôle par 64cu de la croissance de la tumeur ascitique de Krebs chez la souris.

We have recently demonstrated the existence of a lethal effect due to the transmutation of 64Cu atoms associated with the DNA of in vitro cultured cells: normal monkey cells (kidney) and malignant human cells (alveolar lung carcinoma). The lethal efficiency per decay is high and even higher for the malignant cells. From these results, we have tried to bring about a regression of an ascitic tumor developing in the mouse. The experiments we described show that it is possible to clearly delay (5 X 10(5) ascitic cells injected at t = 0), even to stop for a given number of animals (1 to 2 X 10(4) ascitic cells injected at t = 0), the growth of the tumor owing to some injections of 64Cu totalling about 3 mCi and carried out from the 6th day following inoculation of the malignant cells.