Triple negative breast cancer (TNBC) is associated with a poor prognosis and limited response to traditional chemotherapy, necessitating the exploration of novel treatment approaches. Recent researches have highlighted the interconnected roles of the PI3K/AKT pathway and MAPK pathway in TNBC cells, contributing to the efficacy of treatments. Therefore, the concurrent inhibition of both pathways presents a potential new therapeutic strategy for TNBC patients. This study aimed to evaluate the antitumor efficacy of M17, an AKT allosteric inhibitor and a new synthesized shikonin derivative, both alone and in combination with the MEK inhibitor trametinib. We applied various cellular assays and a subcutaneous 4T1 tumor bearing BALB/c mice model were utilized to assess the in vitro and in vivo antitumor effects. Computational docking and Bio-Layer Interferometry (BLI) were employed to investigate the binding of M17 with AKT. Additionally, flow cytometry, transwell assays, western blotting, and tumor xenograft assays were conducted to explore the potential synergistic mechanisms of the combined therapy. The results demonstrated that M17 exhibited moderate antitumor activity against TNBC cells, but significantly enhanced the apoptotic effects and inhibited proliferation and migration when combined with trametinib. Furthermore, the combination of M17 and trametinib showed even more pronounced antitumor activity in vivo . Mechanistically, the dual therapy synergistically suppressed TNBC by targeting the AKT/mTOR and MEK/ERK signaling pathways and inhibiting epithelial-mesenchymal transition. In conclusion, the findings suggested that the combination of M17 and trametinib holds promise as a synergistic treatment option for TNBC patients.
Lignin, with its complex, high-molecular-weight aromatic polymer structure and stable ether or ester bonds, greatly impedes the efficient degradation of lignocellulosic waste. Bacterial laccases have gained attention for their potential in lignocellulosic waste degradation due to their resilience in extreme conditions and ability to be produced in large quantities. In this study, a novel laccase from Geobacillus thermocatenulatus M17 was identified and expressed in E. coli BL21 (DE3). The enzymatic properties of this M17 laccase, including its tolerance to pH, temperature, metal ions, inhibitors, and organic solvents, were thoroughly investigated. The M17 laccase demonstrated optimal activity at pH 3–6 and at temperatures of 50–60 °C, with Co 2+ enhancing its activity over Cu 2+ , and exhibited strong resistance to organic solvents. Further optimization through mutagenesis led to the engineered D217K variant. The efficiency of the engineered laccase was validated with alkali lignin and various sources of plant biomass. The degradation rate of D217K variant for alkali lignin increased significantly, rising from 66.33 % to 83.27 %. Additionally, for high-lignin-content biomass, the degradation rates improved as follows: wheat stover increased from 7.63 % to 10.29 %, switchgrass from 6.02 % to 7.00 %, and corn stalk from 4.51 % to 6.59 %. In conclusion, this study identified a new bacterial laccase and further enhanced its activity through rational engineering, suggesting its promising application in plant biomass degradation.
危险品化学品经营许可证（带存储）