Felix Major

Asymmetric synthesis and biological evaluation of glycosidic prodrugs for a selective cancer therapy.

A severe limitation in cancer therapy is the often insufficient differentiation between malign and benign tissue using known chemotherapeutics. One approach to decrease side effects is antibody‐directed enzyme prodrug therapy (ADEPT). We have developed new glycosidic prodrugs such as (−)‐(1S)‐26 b based on the antibiotic (+)‐duocarmycin SA ((+)‐1) with a QIC50 value of 3500 (QIC50=IC50 of prodrug/IC50 of prodrug+enzyme) and an IC50 value for the corresponding drug (prodrug+enzyme) of 16 pM. The asymmetric synthesis of the precursor (−)‐(1S)‐19 was performed by arylation of the enantiomerically pure epoxide (+)‐(S)‐29 (≥98 % ee).

CD-Spectroscopy As a Powerful Tool for Investigating the Mode of Action of Unmodified Drugs in Live Cells

Circular dichroism (CD) spectroscopy is a well-known method for the analysis of chiral chemical compounds and is often used for studying the structure and interaction of proteins, DNA and bioactive compounds in solution. Here we demonstrate that CD spectroscopy is also a powerful tool for investigating the cellular uptake and mode of action of drugs in live cells. By means of CD spectroscopy, we identified DNA as the cellular target of several novel anticancer agents based on the highly cytotoxic natural antibiotic CC-1065. Furthermore, time-dependent changes in the CD spectra of drug-treated cells enabled us to rationalize differences in drug cytotoxicity. The anticancer agents rapidly penetrate the cell membrane and bind to cellular DNA as their intracellular target. Thereby, the formation of a reversible noncovalent complex with the DNA is followed by a covalent binding of the drugs to the DNA and the more toxic compounds show a higher stability and a lower alkylation rate. Since no drug manipulation is necessary for this kind of investigation and achiral compounds bound to chiral biomolecules may also show induced CD signals, CD spectroscopy of live cells is not limited to the study of analogues of CC-1065. Thus, it constitutes a general approach for studying the mode of action of bioactive compounds on the cellular and molecular level.

Approaches Targeting KV10.1 Open a Novel Window for Cancer Diagnosis and Therapy

Kv10.1 has recently become generally accepted as a promising cancer target, as it is ectopically expressed in the majority of solid tumors. Due to its cell-surface accessibility, Kv10.1 has a strong potential for tumor treatment and diagnosis. Given that its mode of action is likely independent of conventional cancer pathways such as tyrosine kinases, KV10.1 opens a novel window for treating cancer. In this review we will give an overview of the current status of data linking Kv10.1 to cancer, and propose techniques that could exploit Kv10.1s properties for the management of cancer

Synthesis of a Novel Pentagastrin‐Drug Conjugate for a Targeted Tumor Therapy

The synthesis of the novel pentagastrin seco-CBI conjugate 3, which is based on the highly cytotoxic antitumor antibiotic (+)-duocarmycin SA (1), is reported. A key step in the synthesis is the palladium-catalyzed carbonylation of aryl bromide 7 to give the benzyl ester 16, which is transformed into the new seco-CBI derivative 21 bearing a carboxylic acid ester moiety. Subsequent transformation of 21 into an activated ester followed by the introduction of beta-alanine and tetragastrin led to the new pentagastrin drug 3 that contains a peptide moiety for targeting cancer cells expressing CCK-B/gastrin receptors.

Efficient synthesis of an enantiopure thiasteroid by a double Heck reaction

The thiaestrane 7 was synthesized by two sequential Heck reactions starting from the thiophene derivatives 8a–8c, which contain a (Z)-halogenovinyl group, and the enantiopure hydrindene 2a. The first intermolecular Pd-catalyzed reaction leads to 11a and 11b in a highly regio- and diastereoselective manner. A subsequent intramolecular Heck reaction catalyzed by the palladacycle 4 then gave the thiasteroid 7 with an unusual cis-junction of the rings B and C.

Synthesis and Biological Evaluation of a Novel Pentagastrin- Toxin Conjugate Designed for a Targeted Prodrug Mono- therapy of Cancer

A novel carbamate prodrug 2 containing a pentagastrin moiety was synthesized. 2 was designed as a detoxified analogue of the highly cytotoxic natural antibiotic duocarmycin SA (1) for the use in a targeted prodrug monotherapy of cancers expressing cholecystokinin (CCK-B)/gastrin receptors. The synthesis of prodrug 2 was performed using a palladium-catalyzed carbonylation of bromide 6, followed by a radical cyclisation to give the pharmacophoric unit 10, coupling of 10 to the DNA-binding subunit 15 and transformation of the resulting seco-drug 3b into the carbamate 2 via addition of a pentagastrin moiety.