No abstract

Although some breast cancer patients die due to tumor metastasis rather than from the primary tumor, the molecular mechanism of metastasis remains unclear. Therefore, it is necessary to inhibit breast cancer metastasis during cancer treatment. In this case, after designing and synthesizing CTI-2, we found that CTI-2 treatment significantly reduced breast cancer cell metastasis in vivo and in vitro. Notably, with the treatment of CTI-2 in breast cancer cells, the expression level of E-cadherin increased, while the expression level of N-cadherin and vimentin decreased. In addition, after CTI-2 treatment, those outflow levels for p-ERK, p-p38, and p-JNK diminished, while no significant changes in the expression levels of ERK, JNK, or p38 were observed. Our conclusion suggested that CTI-2 inhibits the epithelial-mesenchymal transition (EMT) of breast carcinoma cells by inhibiting the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, thereby inhibiting the metastasis of breast tumor cells. Therefore, we believe that CTI-2 is another candidate for breast tumor medication.

The treatment of breast cancer mainly relies on chemotherapy drugs, which present significant side effects.

No abstract

In recent years, cyclic peptides have attracted much attention due to their chemical and enzymatic stability, low toxicity, and easy modification. In general, the self-assembled nanostructures of cyclic peptides tend to form nanotubes in a cyclic stacking manner through hydrogen bonding. However, studies exploring other assembly strategies are scarce. In this context, we proposed a new assembly strategy based on cyclic peptides with covalent self-assembly. Here, cyclic peptide-(DPDPDP) was rationally designed and used as a building block to construct new assemblies. With cyclo-(DP)3 as the structural unit and 2,2′-diamino-N-methyldiethylamine as the linker, positively charged nanospheres ((CP)6NS) based on cyclo-(DP)3 were successfully constructed by covalent self-assembly. We assessed their size and morphology by scanning electron microscopy (SEM), TEM, and DLS. (CP)6NS were found to have a strong positive charge, so they could bind to siRNA through electrostatic interactions. Confocal microscopy analysis and cell viability assays showed that (CP)6NS had high cellular internalization efficiency and low cytotoxicity. More importantly, real-time polymerase chain reaction (PCR) and flow cytometry analyses indicated that (CP)6NS-siRNA complexes potently inhibited gene expression and promoted tumor cell apoptosis. These results suggest that (CP)6NS may be a potential siRNA carrier for gene therapy.