A single-chain variable fragment-anticancer lytic peptide (scFv-ACLP) fusion protein for targeted cancer treatment.

Antibody-directed drugs for targeted cancer treatment have become a hot topic in new anticancer drug development; however, antibody-fused therapeutic peptides were rarely documented. Herein, we designed a fusion protein with a cetuximab-derived single-chain variable fragment targeting epidermal growth factor receptor (anti-EGFR scFv) and the anticancer lytic peptide (ACLP) ZXR2, connected by a linker (G4 S)3 and MMP2 cleavage site. The anti-EGFR scFv-ZXR2 recombinant protein showed specific anticancer activity on EGFR-overexpressed cancer cell lines in a concentration- and time-dependent manner, as it can bind to EGFR on cancer cell surfaces. This fusion protein caused cell membrane lysis as ZXR2, and showed improved stability in serum compared with ZXR2. These results suggest that scFv-ACLP fusion proteins may be potential anticancer drug candidates for targeted cancer treatment, which also provide a feasible idea for targeted drug design.

Phase separation of p53 induced by its unstructured basic region and prevented by oncogenic mutations in tetramerization domain.

Liquid-liquid phase separation (LLPS) drives the formation of extensive membrane-less compartments to regulate various cellular biological activities both physiologically and pathologically. It has been widely accepted that LLPS is closely related to amyloid diseases and increasing reports have linked this phenomenon to cancers. Mutations of tumor suppressor protein p53 exist in more than half of malignant tumors, making the protein vitally important in cancer research. Recently, p53 was reported to undergo phase separation, which may regulate the function of p53. The molecular mechanism of p53 phase separation and how this process relates to cancer remains largely unclear. Herein, we find that the disordered unstructured basic region (UBR) plays a crucial role in p53 LLPS, driven by electrostatic and hydrophobic interactions. Mutations in the tetramerization domain (TD) disrupt p53 phase separation by preventing the tetramer formation. Furthermore, our results have revealed that, in response to DNA damage in cell, the wild type (WT) p53 undergoes LLPS, while LLPS in oncogenic mutations is diminished or eliminated. The expression of the target gene of p53 decreased significantly with the mutations and cell survival increased with the mutations. Thus, we propose a novel mechanism of p53 carcinogenesis, whereby oncogenic mutations in TD impair the formation of p53 condensates, decreasing the activation of target genes and promoting cancer progression. This study helps to understand the behavior and function of p53 in a different aspect and may provide insights into cancer therapies targeting p53.

Computer-Aided Design of Lasso-like Self-Assembling Anticancer Peptides with Multiple Functions for Targeted Self-Delivery and Cancer Treatments.

Anticancer peptides are promising drug candidates for cancer treatment, but the short circulation time and low delivery efficiency limit their clinical applications. Herein, we designed several lasso-like self-assembling anticancer peptides (LASAPs) integrated with multiple functions by a computer-aided approach. Among these LASAPs, LASAP1 (CRGDKGPDCGKAFRRFLGALFKALSHLL, 1-9 disulfide bond) was determined to be superior to the others because it can self-assemble into homogeneous nanoparticles and exhibits improved stability in serum. Thus, LASAP1 was chosen for proving the design idea. LASAP1 can self-assemble into nanoparticles displaying iRGD on the surface because of its amphiphilic structure and accumulate to the tumor site after injection because of the EPR effect and iRGD targeting to αVß3 integrin. The nanoparticles could disassemble in the acidic microenvironment of the solid tumor, and cleaved by the overexpressed hK2, which was secreted by prostate tumor cells, to release the effector peptide PTP-7b (FLGALFKALSHLL), which was further activated by the acidic pH. Therefore, LASAP1 could target the orthotopic prostate tumor in the model mice after intraperitoneal injection and specifically inhibit tumor growth, with low systematic toxicity. Combining the multiple targeting functions, LASAP1 represents a promising design of self-delivery of peptide drugs for targeted cancer treatments.

The SGYS motif of TAF15 prion-like domain is critical to amyloid fibril formation.

Misfolding of TATA-box binding protein-associated factor 15 (TAF15) may cause neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS). Some mutations of prion-like domain (PrLD) have been detected in patients with sporadic ALS, suggesting the importance of TAF15-PrLD in ALS pathogenesis. Herein, combining experiments and molecular dynamics (MD) simulations, we investigated the influences of several TAF15-PrLD mutations on the amyloid fibril formation of TAF15-PrLD-extracted peptide segments, and identified an essential ß-amyloid-forming segment from TAF15-PrLD. A pathogenic mutation T2 E71G resulted in significantly enhanced aggregation of the TAF15-PrLD segment T2 (Y56GQSQSGYSQSYGGYENQ73). In addition, the peptide T2 with a strong ß-amyloid-forming tendency was able to induce the liquid to solid phase transition of TAF15-PrLD protein. Further study identified the SGYS motif as a critical segment that promoted the formation of amyloid fibrils, which maintained a stable ß-sheet structure through intermolecular hydrogen bonds and π-π stacking interaction. This work provides a clue to elucidate the molecular pathogenic mechanism of TAF15-associated neurodegenerative diseases, and will direct drug development targeting TAF15.