Preparation and characterization of monoclonal antibody conjugates of the calicheamicins: a novel and potent family of antitumor antibiotics.

The calicheamicin family of antitumor antibiotics are capable of producing double-stranded DNA breaks at sub-picomolar concentrations. Their potency suggested that the calicheamicins would be excellent candidates for targeted delivery and a hydrazide prepared from the most potent and abundant of the naturally occurring derivative, gamma 1I, was linked to oxidized sugars on CT-M-01, an internalizing anti-polyepithelial mucin antibody. The conjugates retained the immunoreactivity of the unmodified antibody and were specifically cytotoxic toward antigen positive tumor cells in vitro and in vivo. Hydrazide analogues of less potent calicheamicin derivatives were also prepared and conjugated to CT-M-01. Comparison of the therapeutic efficacy of the conjugates against the MX-1 xenograft tumor implanted s.c. in nude mice showed that conjugates of derivatives missing the rhamnose, a sugar residue that is part of the DNA binding region of the drug, were not as promising as antitumor therapies. However, conjugates of two derivatives, alpha 3I and N-acetyl-gamma 1I, in which the rhamnose residue is present but the amino sugar residue of the parent drug is either missing or modified, significantly inhibited tumor growth over a 4-fold dose range and produced long-term tumor-free survivors. Sterically hindering methyl groups adjacent to the disulfide in the linker further increased the therapeutic window of these potent conjugates.

Potential antiatherosclerotic agents. 4. [(Functionalized-alkyl)amino]benzoic acid analogues of cetaben.

The synthesis of a series of analogues in which the alkyl group of cetaben is substituted with various functional groups or replaced entirely by a functionalized alkanoyl moiety is described. Also reported are the syntheses of branched-chain (alkylamino)benzoic acids in which branching is specifically localized at the terminus of the alkyl chain. Structure-activity relationships of these compounds, both as hypolipidemic agents and as inhibitors of the enzyme fatty acyl-CoA:cholesterol acyltransferase (ACAT), are discussed. Certain compounds were specifically synthesized to test the hypothesis that groups located near the terminus of the alkyl chain of cetaben might retard metabolic degradation of the molecule and, thus, enhance biological activity. Some of these (48-50) were found to be the most active analogues synthesized.

Potential antiatherosclerotic agents. 2. (Aralkylamino)- and (alkylamino) benzoic acid analogues of cetaben.

The syntheses of a series of (aralkylamino)- and (alkylamino)benzoic acids, as well as the corresponding esters and sodium salts, are described. The compounds were evaluated in vivo in rats for serum sterol and triglyceride lowering activity and in vitro for activity in inhibiting the principle cholesterol-esterifying enzyme of the arterial wall, fatty acyl-CoA:cholesterol acyltransferase (ACAT). Based on a combination of these two activities, cataben sodium (150) was selected for development as a hypolipidemic and potential antiatherosclerotic agent.