Topological data analysis of protein structure and inter/intra-molecular interaction changes attributable to amino acid mutations

The combination of Curcumin and Doxorubicin on targeting PI3K/AKT/mTOR signaling pathway: an in vitro and molecular docking study for inhibiting the survival of MDA-MB-231

The process of tumorigenesis is highly associated with the disruption of cell-cycle regulators and derangement of various signaling pathways, which end up with the inhibition of apoptosis and hyper-activation of survival pathways. The PI3K medicated AKT/mTOR pathway is the widely explained mechanism for cancer cell survival which causes the overexpression of MDM2 and downregulates the p53-BAX mediated apoptotic pathway. Curcumin (CUR), the phyto-compound, derived from Curcuma longa is currently being focused on for its anticancer activities against breast cancer cells, MDA-MB-231, not only because of its minimal cytotoxicity against healthy cells (HEK293) but also because it synergistically sensitizes the activity of Doxorubicin (DOXO) in lower doses, which can be a promising source for complementary drug development. This study aims to investigate the combinatorial effect of CUR and DOXO on PI3K/AKT/mTOR pathway proteins by sequential molecular docking analysis and MD simulation studies. The lower binding affinity of the sequentially docked protein-ligand complex proves the increasing binding affinity of CUR and DOXO in the combinatorial dose. The mRNA expressions of different genes of this pathway are observed and quantified using rt-qPCR, where the decreasing fold change (2-∆∆Ct) indicates the suppression of the AKT/mTOR pathway after co-treatment of CUR and DOXO against MDA-MB-231 cells. These in silico and in vitro findings can be a new horizon for further in vitro and clinical trials of breast cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00231-2.

Plectasin: from evolution to truncation, expression, and better druggability

Non-computational classical evolution analysis of plectasin and its functional relatives can especially contribute tool value during access to meet requirements for their better druggability in clinical use. Staphylococcus aureus is a zoonotic pathogen that can infect the skin, blood, and other tissues of humans and animals. The impact of pathogens on humans is exacerbated by the crisis of drug resistance caused by the misuse of antibiotics. In this study, we analyzed the evolution of anti-Staphylococcus target functional sequences, designed a series of plectasin derivatives by truncation, and recombinantly expressed them in Pichia pastoris X-33, from which the best recombinant Ple-AB was selected for the druggability study. The amount of total protein reached 2.9 g/L following 120 h of high-density expression in a 5-L fermenter. Ple-AB was found to have good bactericidal activity against gram-positive bacteria, with minimum inhibitory concentration (MIC) values ranging between 2 and 16 μg/mL. It showed good stability and maintained its bactericidal activity during high temperatures, strong acid and alkali environments. Notably, Ple-AB exhibited better druggability, including excellent trypsin resistance, and still possessed approximately 50% of its initial activity following exposure to simulated intestinal fluids for 1 h. In vitro safety testing of Ple-AB revealed low hemolytic activity against mouse erythrocytes and cytotoxicity against murine-derived macrophages. This study successfully realized the high expression of a new antimicrobial peptide (AMP), Ple-AB, in P. pastoris and the establishment of its oral administration as an additive form with high trypsin resistance; the study also revealed its antibacterial properties, indicating that truncation design is a valuable tool for improving druggability and that the candidate Ple-AB may be a novel promising antimicrobial agent.