Synthesis, characterization, toxicity, cytogenetic and in vivo antitumor studies of 1,1-dithiolate Cu(II) complexes with di-, tri-, tetra- amines and 1,3-thiazoles. Structure-activity correlation.

A series of new mixed-ligand neutral copper(II) complexes of the general type [Cu(amine)(i-MNT)] and [Cu(tz)(i-MNT)] was prepared and characterized by elemental, spectroscopic methods, mu(eff), Lambda(mu) measurements and molecular modeling studies. The acute toxicity, the cytogenetic and the in vivo antitumor activity of the new complexes, is related to their chemical and physicochemical properties. Among the Cu(II) compounds tested the complex with 2-amino-5-methyl thiazole increases significantly the life span of leukemia P388 bearing mice in vivo.

Synergistic antitumor activity of oxaliplatin in combination with gemcitabine in pancreatic tumor-bearing mice.

Oxaliplatin (OX) and gemcitabine (GEM) are both drugs with proven clinical activity in various tumor types, have no overlapping toxic side effects and are different with respect to cellular metabolism. Therefore, we performed an in vivo study to determine the efficacy of the combination of these two drugs to optimize the scheduling of both substances using pancreatic ductal adenocarcinoma PAN-02, subcutaneously growing in C57Bl mice. A total of 164 mice were used for cytotoxicity and antitumor studies. The combination therapy resulted in better results than those observed when the drugs were administered individually. GEM (58 mg/kg) and OX (1.0 mg/kg) achieved a 52% reduction in tumor size on day 28 after transplantation and a T/C value of 168% when the intermittent treatment schedule on days 1, 4 and 7 after inoculation was used. This treatment schedule was superior to other therapeutic schedules, producing a synergistic antitumor effect much higher than the one expected by the simple addition of the effects by OX and GEM acting independently.

In vivo anticancer, anti-inflammatory, and toxicity studies of mixed-ligand Cu(II) complexes of dien and its Schiff dibases with heterocyclic aldehydes and 2-amino-2-thiazoline. Crystal structure of [Cu(dien)(Br)(2a-2tzn)](Br)(H(2)O).

A new series of complexes of the type [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], where dien=diethylenetriamine and dienXX=Schiff dibase of diethylenetriamine formed with 2-furaldehyde (dienOO), 2-thiophenecarboxaldehyde (dienSS), or pyrrol-2-carboxaldehyde (dienNN); Y=Cl, Br or NO(3); and 2a-2tzn=2-amino-2-thiazoline, were synthesized and their structure established by C, H, N and Cu analysis; IR and electronic spectra; magnetic susceptibility; and molar conductivity. The isolated complexes are monomers, paramagnetic, and electrolytes of types 1:1 or 1:2. In both types of solid state complexes, [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], dien and its Schiff dibases are bonded to Cu(II) in a tridentate fashion through 3N atoms. The coordination sphere is completed by the endocyclic nitrogen of the thiazoline moiety and by two Cl, Br, or NO(3) groups with distorted octahedral geometry. The proposed structure of these compounds was supported by X-ray analysis of [Cu(dien)(Br)(2a-2tzn)](Br)(H(2)O). The coordination polyhedron around the copper atom can be described as a distorted square pyramid [Cu(dien)(Br)(2a-2tzn)](+). Its basal plane is occupied by the four nitrogen atoms of the dien and thiazoline ligands with Cu-N distances ranging between 1.996(6) and 2.032(3)A, and the axial position is occupied by one of the two bromine atoms (Br1) with a Cu1-Br1 bond distance of 2.782(1)A. The second bromine atom (Br2) is 4.694(2)A from the copper atom, which exists as a discrete anion and is responsible for the cationic nature of the complex. Results regarding toxicity, antitumor, and anti-inflammatory activities of the investigated compounds are promising and allow the selection of a lead compound for further biological studies.

Octreotide neutralizes dexamethasone antitumor actions on P388 murine lymphocytic leukemia in vivo.

PURPOSE: A wide variety of human malignancies, including lymphoproliferative neoplasms, express somatistatin (SS) receptors (SS-R). SS induces apoptosis and exerts pronounced antiproliferative effects on various human tumors cell lines, human xenografts, and animal tumors including P388 lymphocytic leukemia. In patients with thymoma the combination of octreotide (OCT) with corticosteroids improves the overall response rate. It has been reported that SS can increase glucocorticoid activity. Hereby, we studied the in vitro and in vivo activity of the SS analogue OCT and of the glucocorticoid dexamethasone (DEX) alone or in combination against the murine P388 lymphocytic leukemia. MATERIALS AND METHODS: Cultures of P388 lymphocytic leukemia and BDF(1) male mice implanted with P388 cells where used for the in vitro an in vivo evaluation of the antileukemic activity of SS and DEX. RESULTS: OCT induced a moderate and DEX a satisfactory cytostatic effect in vitro. OCT produced borderline antileukemic effect when administered on days 1-5 while DEX was effective in all schemes and routes of administration. However, none of the combination schemes exerted any anti-leukemic activity both in vitro and in vivo. CONCLUSION: Since both SS and glucocorticoids exert direct (via receptors) and indirect antitumor actions (regulation of growth factor activity) on several cell lines, in vitro and in vivo, it becomes obvious that further in vitro studies shall provide the molecular evidence for the signal transduction pathways which are involved in the interactions of such important anticancer drugs. Based on the results of the present study, the simultaneous use of these drugs in clinical practice should be carefully considered.

A comparative study on cytogenetic and antineoplastic effects induced by two modified steroidal alkylating agents.

We investigated the effects of two newly synthesized steroidal derivatives of nitrogen mustard on sister chromatid exchange rates and on human lymphocyte proliferation kinetics. The compound 33-hydroxy-5alpha,22alpha-spirostan- 12-one-p-(N,N-bis(2-chloroethyl)amino)phenylacetate(1) was, on a molar basis, less effective in inducing sister chromatid exchange and suppressing cell proliferation rate indices than compound 3beta-hydroxy-12alpha-aza-C-homo-5alpha,22alpha-spirostan-12-one-p-(N,N-bis(2-chloroethyl)amino)phenylacetate(2). A correlation was observed between the magnitude of the sister chromatid exchange response and the depression of cell proliferation index. We also studied the effects of the aforementioned compounds on Lewis lung carcinoma. The order of the percent inhibition of tumor growth achieved by the compounds coincides with the order of the cytogenetic effects they induce.

Effect of navelbine on inhibition of tumor growth, cellular differentiation and estrogen receptor status on Lewis lung carcinoma.

We studied the antitumor activity of Navelbine (NVB) together with its ability to induce cellular differentiation and to influence estrogen receptor status of Lewis lung carcinoma (LLC). A total of 32 C(57)B1 mice divided into 5 groups were used for transplantation of LLC. Four groups of mice were treated with 5.0, 2.5 and 1.25 mg/kg/day from day 1 to 9 and 1.25 mg/kg on days 1, 7 and 13. Eight mice were controls. The dose of 1.25 mg/kg/day was the most effective and produced 72.7% inhibition of tumor growth. Ultrastructurally, on day 1 the cells showed poor differentiation. On day 14, in the case of 72.7% inhibition of tumor growth the study revealed a significant restoration of the morphology of the cells. Estrogen receptors gave a positive value in contrast to the initial measurement which was negative. The present study demonstrated good antitumor activity of NVB on LLC. NVB may also induce cellular differentiation and influence the estrogen receptor status.