Application of self-assembly peptides targeting the mitochondria as a novel treatment for sorafenib-resistant hepatocellular carcinoma cells.

Currently, there is no appropriate treatment option for patients with sorafenib-resistant hepatocellular carcinoma (HCC). Meanwhile, pronounced anticancer activities of newly-developed mitochondria-accumulating self-assembly peptides (Mito-FF) have been demonstrated. This study intended to determine the anticancer effects of Mito-FF against sorafenib-resistant Huh7 (Huh7-R) cells. Compared to sorafenib, Mito-FF led to the generation of relatively higher amounts of mitochondrial reactive oxygen species (ROS) as well as the greater reduction in the expression of antioxidant enzymes (P < 0.05). Mito-FF was found to significantly promote cell apoptosis while inhibiting cell proliferation of Huh7-R cells. Mito-FF also reduces the expression of antioxidant enzymes while significantly increasing mitochondrial ROS in Huh7-R cells. The pro-apoptotic effect of Mito-FFs for Huh7-R cells is possibly caused by their up-regulation of mitochondrial ROS, which is caused by the destruction of the mitochondria of HCC cells.

Bispyrene-Based Self-Assembled Nanomaterials: In Vivo Self-Assembly, Transformation, and Biomedical Effects.

Self-assembled nanomaterials show potential high efficiency as theranostic agents for high-performance imaging and therapy. However, superstructures and properties of preassembled nanomaterials are somewhat compromised under complicated physiological conditions. Given the advantages of the dynamic nature and adaptive behavior of self-assembly systems, we propose an "in vivo self-assembly" strategy for in situ construction of nanomaterials in living objects. For the proof-of-concept study of in vivo self-assembly, we developed a bispyrene (BP) molecule as a multifunctional building block. BP molecules show nonfluorescence in the monomeric state. Quantum-chemical calculations indicate that BP forms twisted intramolecular charge transfer states, which are separated into two orthogonal units, preventing the fluorescence emission. Interestingly, the typical excimeric emission of BP is observed with the formation of J-type aggregates, as confirmed by single-crystal X-ray diffraction. Packing of the BP molecules generates parallel pyrene units that interact with adjacent ones in a slipped face-to-face fashion through intermolecular π-π interactions. BP and/or its amphiphilic derivatives are capable of self-aggregating into nanoparticles (NPs) in aqueous solution because of the hydrophobic and π-π interactions of BP. Upon specific biological stimuli, BP NPs can be transformed into variable self-assembled superstructures. Importantly, the self-assembled BP NPs exhibit turn-on fluorescence signals that can be used to monitor the self-assembly/disassembly process in vitro and in vivo. On the basis of the photophysical properties of BP and its aggregates, we synthesized a series of designed BP derivatives as building blocks for in situ construction of functional nanomaterials for bioimaging and/or therapeutics. We observed several new biomedical effects, e.g., (i) the assembly/aggregation-induced retention (AIR) effect, which shows improved accumulation and retention of bioactive nanomaterials in the regions of interests; (ii) the transformation-induced surface adhesion (TISA) effect, which means the BP NPs transform into nanofibers (NFs) on cell surfaces upon binding with specific receptors, which leads to less uptake of BP NPs by cells via traditional endocytosis pathway; and (iii) transformation of the BP NPs into NFs in the tumor microenvironment, showing high accumulation and long-term retention, revealing the transformation-enhanced accumulation and retention (TEAR) effect. In this Account, we summarize the fluorescence property and emission mechanism of BP building blocks upon aggregation in the biological environment. Moreover, BP-derived compounds used for in vivo self-assembly and transformation are introduced involving modulation strategies. Subsequently, unexpected biomedical effects and applications for theranostics of BP based nanomaterials are discussed. We finally conclude with an outlook toward future developments of BP-based self-assembled nanomaterials.

(1-Pyrenylmethyl)amino alcohols, a new class of antitumor DNA intercalators. Discovery and initial amine side chain structure-activity studies.

In the series of 1-pyrenylmethylamines studied in this work the relationships among structure, interaction with DNA, and murine antitumor activity were examined. Binding studies show that all of these 1-pyrenylmethylamine derivatives bind to some extent to DNA by intercalation. The presence of additional basic amine groups in the side chain enhances DNA binding due to electrostatic interactions. Those compounds containing only a single basic benzylic amine bind similarly to DNA. Only the presence of bulky side chains appears to decrease the DNA interactions in the compounds examined. Although antitumor activity is seen for (1-pyrenylmethyl)amino alcohols, useful antitumor activity in the series is limited to those congeners bearing the 2-amino-1,3-propanediol-type side chain. These derivatives bind moderately to DNA. DNA binding is a necessary but not sufficient criterion for antitumor activity in the series. In addition, the strength of DNA binding does not correlate with the antitumor activity in the group of active compounds. Three related 2-[(arylmethyl)amino]-1,3-propanediol derivatives (AMAPs) [crisnatol (770U82), 773U82, and 502U83] are currently in clinical trials as potential antitumor agents.