Bernard F. Spielvogel

The antineoplastic activity of trimethylamine carboxyboranes and related esters and amides in murine and human tumor cell lines.

Trimethylamine carboxyboranes including their esters and amides were shown to have antineoplastic activity in vivo against Ehrlich ascites carcinoma growth. The derivatization to the ester or amide did not necessarily improve activity. Cytotoxicity of the derivatives was observed against the growth of murine and human tumor cells. Selectivity was demonstrated by the boron derivatives in the human solid tumor screens. Almost all the compounds demonstrated cytotoxicity against single-cell suspension growths, eg Tmolt3, L1210, HeLa-S3. Selection of two compounds to examine their mode of action in L1210 lymphoid leukemia cells showed that the agents perferentially inhibited DNA synthesis followed by protein and RNA synthesis. The d(TTP) pools were markedly reduced because of inhibition of nucleotide kinase activity. The agents also inhibited regulatory enzymes in the de novo purine pathway and afforded DNA strand scission. These effects by the agents were probably additive to bring about tumor cell death.

Boronated Dipeptide Borotrimethylglycylphenylalanine as a Potential Boron Carrier in Boron Neutron Capture Therapy for Malignant Brain Tumors

Abstract Takagaki, M., Ono, K., Masunaga, S-I., Kinashi, Y., Oda, Y., Miyatake, S-I., Hashimoto, N., Powell, W., Sood, A. and Spielvogel, B. F. Boronated Dipeptide Borotrimethylglycylphenylalanine as a Potential Boron Carrier in Boron Neutron Capture Therapy for Malignant Brain Tumors. Radiat. Res. 156, 118–122 (2001). A boronated dipeptide, borotrimethylglycylphenylalanine (BGPA), was synthesized as a possible boron carrier for boron neutron capture therapy (BNCT) for malignant brain tumors. In vitro, at equal concentrations of 10B in the extracellular medium, BGPA had the same effect in BNCT as p-boronophenylalanine (BPA). Boron analysis was carried out using prompt γ-ray spectrometry and track-etch autoradiography. The tumor:blood and tumor:normal brain 10B concentration ratios were 8.9 ± 2.1 and 3.0 ± 1.2, respectively, in rats bearing intracranial C6 gliosarcomas using α-particle track autoradiography. The IC50, i.e. the dose capable of inhibiting the growth of C6 gliosarcoma cells by 50% after 3 days of incubation, was 5.9 × 10–3 M BGPA, which is similar to that of 6.4 × 10–3 M for BPA. The amide bond of BGPA is free from enzymatic attack, since it is protected from hydrolysis by the presence of a boron atom at the α-carbon position of glycine. These results suggest promise for the use of this agent for BNCT of malignant brain tumors. Further preclinical studies of BGPA are warranted, since BGPA has advantages over both BPA and BSH.

SYNTHESES OF NOVEL SUBSTITUTED-BORANOPHOSPHATE NUCLEOSIDES

ABSTRACT A number of substituted (borano) nucleic acids, 3′-[diethylphosphite-(cyano, carboxy, or carbamoyl) borano] deoxynucleosides (3a–4c) and 5′-[diethylphosphite(cyano or carboxy) borano] deoxynucleosides (6a–7d) were prepared by a variety of synthetic procedures. The syntheses of the pyrophosphates (2a–2c), as precursors for 3a–4c, are also described.

The Effects of Amine-Carboxyborane Related Derivatives on UMR-106 Bone Metabolism.

The amine-carboxyboranes and related derivatives have been shown to be potent anti-inflammatory and anti-osteoporosis agents. Their action in part appears to be mediated by the modulation of cytokines, e.g. TNFα or IL-1. Previous studies have demonstrated that LPS induced macrophages release of TNFα maximally at 60 to 90 min. and IL-1 from 5 to 8 hr. The amine-carboxyboranes reduced significantly the release of these cytokines but also blocked TNFα high affinity binding to UMR-106 receptor at 90 min. at 10 μM, and IL-1 high affinity binding at 5 hr. at 12.5 μM. In addition, the agents suppressed IL-8 binding to CHO K1 high affinity receptor at 24 hr. at 50 μM and IL-2 binding to HuT-8 receptors at 25 μM at 90 min. and 5 hr. Correlation of metabolic events associated with osteoporosis showed that at 90 min., when TNFα receptor binding was reduced by the agents, calcium uptake into UMR-106 cells was reduced at 10 μM as well as the acid and alkaline phosphatases, and the prostaglandin cyclo-oxygenase activities and adhesion of leukocytes and macrophages to UMR-106 cell monolayers. At 5hr. when the agents reduced IL-1 binding to UMR-106 receptors, calcitonin and 1,25-dihydrovitamin D3 binding was reduced by the agents as was acid and alkaline phosphatase, and 5′-lipoxygenase activities and white blood cell adhesion. At this time calcium uptake and proline incorporation was increased significantly by the agents. At later times e.g. 18-48 hr. calcium uptake was still increased, and NAG activity was inhibited in the presence of the agents. These effects may be related more to the inhibition of other cytokine receptor binding, e.g. IL-8. Thus, many of the observed metabolic effects of amine-carboxyboranes as antiosteoporosis agents can be correlated with their inhibition of cytokine high affinity binding to target cell receptors.

DNA interaction with metal complexes and salts of substituted boranes and hydroborates in murine and human tumor cell lines.

A series of metal complexes and sodium salts of substituted boranes and hydroborates was shown to have cytotoxicity in murine and human tumor screens. Most of these agents were active against the growth of L-1210, Tmolt3 and Hela-S3. Selected agents demonstrated activity against the growth of monolayer human cell lines derived from solid tumors. Interestingly, many of the compounds demonstrated even lower ED50 values in the solid tumor than the L-1210 leukemic screen. Four compounds, Cu2(m-CH3)3NBH2CO2)4.2(CH3)NBH2COOH (I), [Fe3O((CH3)3NBH2CO2)6(CH3OH)3]NO3.CH3CN (II), cis-[Co(en)2((CH3)3N.BH2CO2)2]Cl.2.5 H2O.0.5 CH3OH (V), and Na(CH3)3NBH2CO2.0.25 CH3OH (IX) were shown preferentially to inhibit DNA synthesis of L-1210 cells with only moderate inhibition of RNA and protein synthesis. In preliminary studies these agents effectively inhibited the activities of regulatory enzymes involved in the purine pathway and nucleoside kinases resulting in the suppression of d(NTP) pool levels. The boron derivatives also caused L-1210 DNA strand scission. These drugs may act together to inhibit DNA synthesis and induce cytotoxicity.

CRYSTAL STRUCTURE OF AN ANTI-NEOPLASTIC AGENT, O-TOLUIDINECYANOBORANE, C8H11BN2

Figure 1. Molecu la r s t ructure ( 5 0 % d i sp lacemen t e l l ipso ids ) of CSHMBNI. T h e selected bond d i s t ances and ang les are: B C 1.584(4) , B N ( l ) 1.593(4), C N 1.147(3), N ( l ) C ( l ) 1 .466(3) , C ( l ) C ( 6 ) 1 .390(3) , C ( l ) C ( 2 ) 1.380(3) , C ( 2 ) C ( 3 ) 1.398(4) , C ( 2 ) C ( 2 1 ) 1.502(4), C(3) -C(4) 1.375(4) A ; C B N ( l ) 111.7(2) , N C B 174.0(3) , C ( l ) N ( l ) B 117.1(2) , C ( 6 ) C ( l ) C ( 2 ) 122.2(2) , C ( 6 ) C ( l ) N ( l ) 117.5(2) , C ( 2 ) C ( l ) N ( l ) 120.4(2) , C ( l ) C ( 2 ) C(3 ) 116.9(2) , C ( l ) C ( 2 ) C ( 2 1 ) 122.5(2), C(3) -C(2) -C(21) 120.6(2) , C (4 ) -C(3 ) -C(2 ) 121.6(2) , C(5 ) -C(4) -C(3) 120.1(3)°.

Boronated pyrimidines and purines as cytotoxic, hypolipidemic and anti-inflammatory agents.

The simple boronated bases, e.g. cytosine, adenine and guanine, containing no sugar residues retained good pharmacological activity as hypolipidemic, anti-neoplastic and anti-inflammatory agents in mice at 8 mg/kg. Their activities were generally identical to their respective nucleoside derivatives. Interestingly the boronated acyclovir derivative was a very potent hypolipidemic agent achieving better activity than clofibrate and lovastatin. The boronated adenine derivatives appeared to have the best anti-inflammatory activity in reducing local edema and analgesic effects. The agents were active against the growth of murine and human leukemias and human HeLa-S3 suspended uterine carcinoma. Only the boronated adenine derivatives were effective in blocking the growth of human SW480 adenocarcinoma and the KB nasopharynx.

Synthesis and crystal structure of hexakis(ammonia–cyanoborane)- sodium iodide

The preparation of the crystalline complex [Na{NH3·BH2(CN)}6]I from NMe3·BH2I and NaCN in liquid NH3 is described. Structural details have been obtained by single-crystal X-ray analysis of therhombohedral crystals which belong to space group R, with a=b=c= 8.506(4)A, α=β=γ= 82.54(4)°, and Z= 1. The structure has been solved by the heavy-atom method from 1 293 unique reflections measured by diffractometer and refined by full-matrix least-squares calculations to R 0.063. The NH3·BH2(CN) units are arranged in a regular octahedral manner about both the Na+ and I– ions with Na+⋯ N(cyano) 2.487(4)A and Na+⋯ N–C 134.2(4)°; evidence for a linear correlation between such distances and angles in related complexes is presented. The B–N, B–C, and CN distances are 1.581(8), 1.579(8), and 1.152(7)A, respectively.

The Hypolipidemic and Anti-Inflammatory Activity of BoronatedAromatic Amino Acids in CF1 Male Mice

The boronated aromatic amino acids were shown to be potent hypolipidemic agents in mice lowering both serum cholesterol and triglycerides after 16 days. Selective compounds were as effective as the clinical standards. Furthermore, the compounds were effective anti-inflammatory agents reducing local and central pain as well as suppressing LPS induced endotoxic shock in mice. These agents inhibited lysosomal and proteolytic enzymes of the liver and macrophages as a part of their mechanism of action.

Synthesis of Trimethylamine-[14C]carboxyborane and Trimethylamine-[14C]carboxymethoxyborane and L1210 Leukemia Cell Uptake

The anti-neoplastic agents trimethylamine-carboxyborane and its corresponding methyl ester have successfully been radiolabeled with carbon-14 in the carboxyl group. Using the radiolabeled agents we have shown that their L1210 leukemia cell uptake appeared to be by a passive process and binding of the agents to DNA, RNA and protein over 24 h was minimal.