Synthesis and cytotoxicity of a new class of potent decapeptide macrocycles.

Described are the syntheses of five decapeptides that are C-2-symmetrical derivatives of the natural product pentapeptide sansalvamide A. Derivatives were made using a succinct convergent synthesis. These analogues share no structural homology to current cancer drugs, are cytotoxic at levels on par with existing drugs treating cancers, and demonstrate selectivity for drug-resistant pancreatic cancer cell lines over noncancerous cell lines. These molecules are excellent chemotherapeutic leads in the search for new anticancer agents.

Synthesis of second-generation sansalvamide A derivatives: novel templates as potential antitumor agents.

We report the synthesis of 34 second-generation Sansalvamide A derivatives. San A derivatives have unique anticancer properties and target multiple cancers, including colon, pancreatic, breast, prostate, and melanoma. As novel templates, the derivatives described herein explore the role of stereochemistry, amide bond geometry, transannular hydrogen bonding, and polarity on antitumor potency. Testing the chemotherapeutic activity of these derivatives against multiple cancer cell lines will provide clear structural motifs and identify conformational space that is important for cytotoxicity. The 34 compounds presented are divided into six series, where five series involve the insertion of D-amino acids in conjunction with four structural features at each of the five positions of the macrocycle. The sixth series involves comparison between all L- and all D-amino acid derivatives with N-methyls placed at each position around the macrocyclic core. The four structural features explored in conjunction with D-amino acids include N-methyl amino acids, aromatic amino acids, polar amino acids, and hydrophobic alkyl amino acids.

Synthesis of Sansalvamide A derivatives and their cytotoxicity in the MSS colon cancer cell line HT-29.

We report the synthesis of thirty-six Sansalvamide A derivatives, and their biological activity against colon cancer HT-29 cell line, a microsatellite stable (MSS) colon cancer cell-line. The thirty-six compounds can be divided into three subsets, where the first subset of compounds contains L-amino acids, the second subset contains D-amino acids, and the third subset contains both D- and L-amino acids. Five compounds exhibited excellent inhibitory activity (>75% inhibition). The structure-activity relationship (SAR) of the compounds established that a single D-amino acid in position 2 or 3 gave up to a 10-fold improved cytotoxicity over Sansalvamide A peptide. This work highlights the importance of residues 2 and 3 and the role of D-amino acids in the extraordinary SAR for this compound class.

Synthesis and novel structure-activity relationships of potent sansalvamide A derivatives.

Synthesis of twelve Sansalvamide A derivatives and their SAR against colon cancer (HT-29).