Synthesis of Prostate-Specific Membrane Antigen-Targeted Bimodal Conjugates of Cytotoxic Agents and Antiandrogens and Their Comparative Assessment with Monoconjugates.

Prostate cancer is the second most common cancer among men. We designed and synthesized new ligands targeting prostate-specific membrane antigen and suitable for bimodal conjugates with diagnostic and therapeutic agents. In vitro studies of the affinity of the synthesized compounds to the protein target have been carried out. Based on these ligands, a series of bimodal conjugates with a combination of different mitosis inhibitors and antiandrogenic drugs were synthesized. The cytotoxicity of the compounds obtained in vitro was investigated on three different cell lines. The efficacy of the two obtained conjugates was evaluated in vivo in xenograft models of prostate cancer. These compounds have been shown to be highly effective in inhibiting the growth of PSMA-expressing tumors.

Synthesis and initial in vitro evaluation of PSMA-targeting ligands with a modified aromatic moiety at the lysine ε-nitrogen atom.

We report an improved series of ligands targeting prostate specific membrane antigen (PSMA). The new compounds were designed by the introduction of changes in the structure of the aromatic fragment at ε-nitrogen atom of lysine that resulted in improved biological parameters. Some of them demonstrated high selectivity and nanomolar IC50 values. We synthesized and tested two conjugates with a fluorescent label Sulfo-Cy5 as an example of the use of the obtained PSMA inhibitors as a basis for the creation of diagnostic preparations.

Thiourea Modified Doxorubicin: A Perspective pH-Sensitive Prodrug.

A novel approach to the synthesis of pH-sensitive prodrugs has been proposed: thiourea drug modification. Resulting prodrugs can release the cytotoxic agent and the biologically active 2-thiohydantoin in the acidic environment of tumor cells. The concept of acid-catalyzed cyclization of thioureas to 2-thiohydantoins has been proven using a FRET model. Dual prodrugs of model azidothymidine, cytotoxic doxorubicin, and 2-thiohydantoin albutoin were obtained, which release the corresponding drugs in the acidic environment. The resulting doxorubicin prodrug was tested on prostate cancer cells and showed that the thiourea-modified prodrug is less cytotoxic (average IC50 ranging from 0.5584 to 0.9885 µM) than doxorubicin (IC50 ranging from 0.01258 to 0.02559 µM) in neutral pH 7.6 and has similar toxicity (average IC50 ranging from 0.4970 to 0.7994 µM) to doxorubicin (IC50 ranging from 0.2303 to 0.8110 µM) under mildly acidic conditions of cancer cells. Cellular and nuclear accumulation in PC3 tumor cells of Dox prodrug is much higher than accumulation of free doxorubicin.