L. Perissin

Analysis of the HMGI nuclear proteins in mouse neoplastic cells induced by different procedures

Four malignant tumors induced in mouse by different experimental procedures were compared as regards their high-mobility-group (HMG) proteins. All tumors showed the complete set of three HMG proteins which we call HMGI-C, I-D, and I-E. The presence of the three HMGI proteins is a characteristic of the transformed phenotype regardless of whether the tumor was chemically, virally, or spontaneously derived. However, the level of expression of the HMGI proteins is not constant in the four tumors. Using reverse-phase HPLC, the individual HMGI proteins were isolated from the spontaneously derived tumor (Lewis lung carcinoma) and shown by amino acid analysis to be similar to those previously obtained from a tumor grown in nude mice by inoculation of in vitro-transformed cells.

Effects of stress on tumor growth and metastasis in mice bearing lewis lung carcinoma

The progression of Lewis lung carcinoma has been examined in mice under the stress of different housing and experimental conditions. The maintenance of the animals in a low stress environment decreased the weight of spontaneous lung metastases in comparison with conventional housing. The handling of mice in the low stress environment for intraperitoneal saline administration increased metastasis formation, whereas the application of a psychological stressor (spatial disorientation) to these animals increased both primary tumor growth and metastasis formation. These results indicate that psychological and experimental stressors can modulate, presumably via neuroendocrine mechanisms, the hosts antitumor responses which can control metastases and primary tumor independently from each other.

Coordination metal complexes of Rh(I), Ir(I) and Ru(II): recent advances on antimetastatic activity on solid mouse tumors

Abstract Following pioneering observations on the mouse Ehrlich ascites carcinoma, the result of cooperation between the Institutes of Chemistry and Pharmacology of the University of Trieste, more recent studies have characterized some aspects of the antimetastatic properties of coordination metal complexes other than platinum compounds. The compounds examined, rhodium(I) and iridium(I) derivatives of the type [Mchel(LL)] +/o (chel= pyridinalimine (NNR), acetylacetonate; LL= 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene), both with a square-planar structure, and an octahedral ruthenium(II) derivative RuCl 2 (dimethylsulfoxide) 4 were tested using the solid metastasizing tumor of the mouse, Lewis lung carcinoma. The conclusions which can be drawn from the resulting data concern the role of the metal, of the leaving group and of the non-leaving group as well. It was found that the organometallic complexes of Rh(I) are more active than those of Ir(I); within the Rh(I) derivatives of the type [Rh(I)COD(NNR)] + Cl − (RCH 3 , C 2 H 5 , iC 3 H 7 ), the higher the hydrosolubility, the higher is the antitumor and particularly the antimetastatic effect; as far as the diolefinic ligands are concerned, the higher the chelating effect the higher are the antimetastatic properties of the resulting compound. Separate conclusions can be made for the Ru(II) derivative. Comparison of its antimetastatic effects with those of cis -dichlorodiammineplatinum(II) (cisplatin) using three solid mouse tumors, clearly shows a better therapeutic index for the former, suggesting that within this class of compounds it is conceivable to obtain derivatives with an antineoplastic activity comparable to or even higher than that of cisplatin.

Effects of rotational stress on the effectiveness of cyclophosphamide and razoxane in mice bearing Lewis lung carcinoma

The effects of conventional vs protected housing, and those caused by the periodic application of a psychological Stressor (rotational stress, spatial disorientation) on mice kept in a protected housing, with spontaneous tumor metastasis have been determined in mice implanted with Lewis lung carcinoma as a function of tumor inoculum size and response to treatment with cyclophosphamide and razoxane. With a reduced inoculum size, tumor takes do not occur in mice kept in the protected housing, but do occur with spatial disorientation. With a larger inoculum size, tumor takes occur in all untreated mice, and the weight of spontaneous lung metastasis is significantly increased by spatial disorientation. For mice in protected housing, cyclophosphamide results in the absence of macroscopically detectable tumors in all of the treated mice, whereas the use of spatial disorientation abolishes this therapeutic action. The antimetastatic effects of razoxane are also reduced by rotational stress. These results indicate that housing conditions and a psychological stressor can control tumor takes and metastasis formation. They also indicate that hosts antitumor resistance effectors, which are susceptible to neuroendocrine modulation by environmental and psychological Stressors, participate to determine the effectiveness of the treatment with a cytotoxic (cyclophosphamide) and antimetastatic (razoxane) antitumor drug.

A non‐invasive simple method for measurement of urinary excretion of melatonin in undisturbed mice

Abstract: Melatonin is a hormone involved in neuroendocrine responses; its plasma concentrations display a circadian pattern which is modified by stress. Studies for determining the effects of stressors on melatonin levels in laboratory animals present the difficulty that the procedures for blood sampling are by themselves potential stressors capable of influencing the levels of the hormone measured. A simple non‐stressful method for measuring urinary excretion of melatonin has been consequently developed. The method is applicable to single undisturbed mice kept in conventional cages, and consists of urine collection on chromatographic paper followed by extraction and melatonin assay by radioimmunoassay. The use of this method with BD2F1 mice indicates nocturnal excretion of melatonin significantly higher than during the day; nighttime melatonin levels were shown to be suppressed by constant illumination. A significant increase in nocturnal melatonin excretion was caused by the application of rotational stress applied as a mild experimental stressor.

Antimetastatic action of the prostacyclin analog iloprost in the mouse.

The antimetastatic activity of the prostacyclin analog Iloprost has been examined in mice bearing Lewis lung carcinoma. An inhibition of lung colony formation is observed when 100 or 200μg/kg Iloprost are administered i.v. 1h before i.v. injection of tumor cells, which is dependent on the size of tumor inoculum. The effects of 200μg/kg Iloprost persist for 24 h, and are of the same magnitude as those obtained with 10 mg/kg prostacyclin, which last only for 30min. When treatment with Iloprost is followed by surgical removal of primary tumor, spontaneous metastasis formation is reduced, and the survival time of the treated animals is significantly increased over controls treated with surgery only. The antimetastatic effects of Iloprost appear dissociated from drugs effects on the hemostatic system of the host as indicated by the clot retraction assay, performed afterin vivo treatment, using ADP or tumor cells as platelet aggregating agents. Iloprost thus appears to reduce spontaneous metastasis formation and intraoperative tumor cell dissemination, with pharmacological properties more favourable to therapeutic use than those of prostacyclin.

Antimetastatic action of orally administered lysozyme in mice bearing Lewis lung carcinoma

The pharmacological activity of orally administered lysozyme, for the control of the growth of solid tumor metastases, was examined in mice bearing Lewis lung carcinoma. Groups of at least 10 tumor-bearing mice, fed daily for three consecutive weeks from subcutaneous tumor implantation with lysozyme, prepared from hen egg-white, had a pronounced reduction of the weight of their metastatic tumor to 25–50 per cent of controls within a wide range of doses (25–200mg/kg/day). The antimetastatic effect was not related to the length of the treatment schedule employed; a short course of 7 days, given on days 1–7 after tumor implantation, proved equally active. The inhibition of the formation of lung metastases, in mice treated with lysozyme prior to tumor inoculation, lasts for at least 2 weeks after discontinuation of treatment, indicating that the antimetastatic activity observed is not associated with cytotoxic activity of the lysozyme, and is probably mediated by the elicitation of host responses. The examination of the therapeutic potential of the antimetastatic action of lysozyme supplied throught the usual diet indicates that this treatment synergizes with the antitumor effects of cisplatin, given to mice after surgical removal of the primary tumor, causing a statistically significant prolongation of the survival time of the animals as compared with chemotherapy alone.

Morphological analysis of metastatic potential and antimetastatic drug effects in mice bearing two lines of Lewis lung carcinoma.

Two lines of Lewis lung carcinoma with a different potential to metastasize spontaneously to the lungs have been examined for their cytological and histological characteristics. Metastatic potential appears to be related with parenchymal organization of the primary tumours, since large haemorrhagic areas containing detached tumour cells and the absence of endothelialized capillaries are observed only in the line with high metastatic potential. At the same time, the cytological characteristics of the cells of the two tumour lines are similar, and do not seem to be related with metastatic potential. After treatment with the selective antimetastatic drugs ICRF-159 and DM-COOK, and with DTIC, the histological appearance of the line with high metastatic potential becomes similar to that of the line with low metastatic potential. These data seem to indicate that the early phases of tumour spread occurring in the primary tumour are of relevance for metastatic potential and control by antimetastatic drugs, and suggest that for DTIC such antimetastatic action may participate to its clinical antitumour effects.

Effects of antimetastatic antiinvasive and cytotoxic agents on the growth and spread of transplantable leukemias in mice

The effects of cytotoxic (cyclophosphamide, CCNU, GANU), antiinvasive (vincristine, vinblastine) and antimetastatic (ICRF-159, DM-COOK) agents have been compared in mice-bearing P388 and L1210 leukemias, and TLX5 lymphoma. The drugs tested increase the survival time of the treated mice in a manner consistent with a cytotoxic action in the case of cyclophosphamide, CCNU, GANU, vincristine and vinblastine. Leukemic infiltration of the brain after i.p. tumor implantation has been determined by bioassay of this organ, and is reduced by treatment with all of the drugs tested, with the exception of ICRF-159. DM-COOK appears to increase the life-span of the treated animals by the inhibition of leukemic spread rather than by a cytotoxic action. The marked cytotoxicity of vincristine and vinblastine is sufficient to account for failure to detect any antimetastatic effects of these agents. The lack of antidisseminative effect observed for ICRF-159 under the experimental conditions employed might be connected with the observation that the antimetastatic action of this drug on solid tumors is due to its effects on tumor blood vessels.

Effects of an inducer and an inhibitor of hepatic metabolism on the antitumor action of dimethyltriazenes.

SummaryTo investigate the role of monomethyltriazenes as the active metabolites of antitumor dimethyltriazenes, the in vivo simultaneous treatment with an inducer (phenobarbital, PB) or an inhibitor (carbon tetrachloride, CCl4) of hepatic drug metabolism was examined in mice bearing Lewis lung carcinoma. Treatment with PB or CCl4 with the dosage and schedules employed proved to be effective in markedly modifying the N-demethylation of the three dimethyltriazenes tested, as had been determined in vitro. No unambiguous increase by PB, or decrease by CCl4, which might theoretically be expected if metabolic conversion to monomethyltriazenes was involved, was observed for the antitumor and antimetastatic activity of dimethyl-triazenes. At the same time, a difference was noted between the effects on primary tumors and those on metastases. These data support the view that generalizations on the relevance of monomethyltriazenes as the active metabolites responsible for the antitumor and antimetastatic activity of dimethyltriazenes may not be valid.