Synthesis and anticancer properties of novel dolastatin 10 analogs featuring five-membered heterocyclic rings with a linkable group at the C-terminus.

Dolastatin 10 (Dol-10), a natural marine-source pentapeptide, is a powerful antimitotic agent regarded as one of the most potent anticancer compounds found to date. Dol-10 however, lacks chemical conjugation capabilities, which restricts the feasibility of its application in targeted drug therapy. This limitation has spurred the prospect that chemical structure of the parent molecule might allow conjugation of the derivatives to drug carriers such as antibodies. By first employing docking studies, we designed and prepared a series of novel Dol-10 analogs with a modified C-terminus, preserving high potency of the parent compound while enhancing conjugation capability. The modifications involved the introduction of a methyleneamine functionality at position 4 of the 1,3-thiazole ring, along with the substitution of the thiazole ring with a 1,2,3-triazole moiety, furnished with methylenehydroxy, carboxy, methyleneamine, and N(Me)-methyleneamine tethering functionalities at position 4. Among the synthesized pentapeptides, DA-1 exhibited the highest potency in prostate cancer (PC-3) cells, eliciting apoptosis (IC50 0.2 ± 0.1 nm) and cell cycle arrest at the mitotic stage after at least 6 days of culture. This delayed response suggests the accumulation of cellular stress or significant physiological alterations that profoundly impact the cell cycle. We believe that these novel Dol-10 derivates represent a new and straightforward route for the development of C-terminus modified Dol-10-based microtubule inhibitors, thereby advancing targeted anticancer therapy.

Algae-Based Nanoparticles for Oral Drug Delivery Systems.

Drug administration by oral delivery is the preferred route, regardless of some remaining challenges, such as short resident time and toxicity issues. One strategy to overcome these barriers is utilizing mucoadhesive vectors that can increase intestinal resident time and systemic uptake. In this study, biomimetic nanoparticles (NPs) were produced from 14 types of edible algae and evaluated for usage as oral DDSs by measuring their size, surface charge, morphology, encapsulation efficiency, mucoadhesion force, and cellular uptake into Caco-2 cells. The NPs composed of algal materials (aNPs) exhibited a spherical morphology with a size range of 126-606 nm and a surface charge of -9 to -38 mV. The mucoadhesive forces tested ex vivo against mice, pigs, and sheep intestines revealed significant variation between algae and animal models. Notably, Arthospira platensis (i.e., Spirulina) NPs (126 ± 2 nm, -38 ± 3 mV) consistently exhibited the highest mucoadhesive forces (up to 3127 ± 272 µN/mm²). Moreover, a correlation was found between high mucoadhesive force and high cellular uptake into Caco-2 cells, further supporting the potential of aNPs by indicating their ability to facilitate drug absorption into the human intestinal epithelium. The results presented herein serve as a proof of concept for the possibility of aNPs as oral drug delivery vehicles.