Biochemical characterization and molecular docking analysis of novel esterases from Sphingobium chungbukense DJ77

Targeted blocking of EGFR and GLUT1 by compound H reveals a new strategy for treatment of triple-negative breast cancer and nasopharyngeal carcinoma

BACKGROUND

Cytoplasmic epidermal growth factor receptor (EGFR) is overexpressed in both nasopharyngeal carcinoma (NPC) and triple-negative breast cancer (TNBC), while clinical outcome and prognosis vary greatly among patients treated with gefitinib, and all patients eventually develop resistance to this agent. Therefore, we propose a new concept for synthesizing multitarget compounds and reveal new therapeutic strategies for NPC and TNBC expressing EGFR.

METHODS

Compound H was synthesized in our previous study. Molecular docking, and cell thermal shift assays (CETSAs) and drug affinity responsive target stability(DARTS) were used to confirm the binding of compound H to EGFR and GLUT1. Methylthiazolyldiphenyl-tetrazolium bromide(MTT), annexin V-PE assays, mitochondrial membrane potential (MMP) assays, and animal models were used to evaluate the inhibitory effect of compound H on TNBC cell lines. Energy metabolism tests, Western blotting, and immunofluorescence staining were performed to evaluate the synergistic effects on EGFR- and glucose transporter type 1(GLUT1)-mediated energy metabolism.

RESULTS

Compound H can simultaneously act on the EGFR tyrosine kinase ATP-binding site and inhibit GLUT1-mediated energy metabolism, resulting in reductions in ATP, MMP, intra-cellular lactic acid, and EGFR nuclear transfer. The anti-tumor activity of compound H is significantly superior to the combination of GLUT1 inhibitor BAY876 and EGFR inhibitor gefitinib. Compound H has remarkable anti-proliferative effects on TNBC MDA-MB231 cells, and importantly, no obvious toxicity effects of compound H were found in vivo.

CONCLUSIONS

Synergistic effects of inhibition of EGFR- and GLUT1-mediated energy metabolism by compound H may present a new strategy for the treatment of TNBC and NPC.

Engineered Geobacillus lipolytic enzymes - Attractive polyesterases that degrade polycaprolactones and simultaneously produce esters

Plastic pollution is one of the biggest environmental problems plaguing the modern world. Polyester-based plastics contribute significantly to this ecological safety concern. In this study, lipolytic biocatalysts GD-95RM and GDEst-lip developed based on lipase/esterase produced by Geobacillus sp. 95 strain were applied for the degradation of polycaprolactone films (Mn 45.000 (PCL45000) and Mn 80.000 (PCL80000)). The degradation efficiency was significantly enhanced by the addition of short chain alcohols. Lipase GD-95RM (1 mg) can depolymerize 264.0 mg and 280.7 mg of PCL45000 and PCL80000, films respectively, in a 24 h period at 30 °C, while the fused enzyme GDEst-lip (1 mg) is capable of degrading 145.5 mg PCL45000 and 134.0 mg of PCL80000 films in 24 h. The addition of ethanol (25 %) improves the degradation efficiency ~2.5 fold in the case of GD-95RM. In the case of GDEst-lip, 50 % methanol was found to be the optimal alcohol solution and the degradation efficiency was increased by ~3.25 times. The addition of alcohols not only increased degradation speeds but also allowed for simultaneous synthesis of industrially valuable 6-hydroxyhexonic acid esters. The suggested system is an attractive approach for removing of plastic waste and supports the principles of bioeconomics.

Biodegradation of polyurethanes by Serratia liquefaciens L135 and its polyurethanase: In silico and in vitro analyses

Polyurethanes (PUs) are found in many everyday products and their disposal leads to environmental accumulation. Therefore, there is an urgent need to develop ecologically sustainable techniques to biodegrade and recycle this recalcitrant polymer and replace traditional methods that form harmful by-products. Serratia liquefaciens L135 secretes a polyurethanase with lipase activity, and this study explores the biodegradation of PUs by this bacterium and its enzyme through in silico and in vitro analyses. PUs monomers and tetramers were constructed in silico and tested with modeled and validated structure of the polyurethanase from S. liquefaciens. The molecular docking showed that all PUs monomers presented favorable interactions with polyurethanase (values of binding energy between -84.75 and -121.71 kcal mol-1), including PU poly[4,4'-methylenebis (phenyl isocyanate)-alt-1,4-butanediol/di (propylene glycol)/polycaprolactone] (PCLMDI). Due to repulsive steric interactions, tetramers showed less favorable interactions (values between 24.26 and -45.50 kcal mol-1). In vitro analyses evaluated the biodegradation of PUs: Impranil® and PCLMDI; this latter showed high binding energy with this polyurethanase in silico. The biodegradation of Impranil® by S. liquefaciens and its partially purified polyurethanase was confirmed in agar by forming a transparent halo. Impranil® disks inoculated with S. liquefaciens and incubated at 30 °C for six days showed rupture of the PU structure, possibly due to the formation of cracks visualized by scanning electron microscopy (SEM). PCLMDI films were also biodegraded by S. liquefaciens after 60 days of incubation, with the formation of pores and cracks visualized by SEM. The biodegradation may have occurred due to the action of polyurethanase produced by this bacterium. This work provides essential information on the potential of S. liquefaciens to biodegrade PUs through in silico analyses combined with in vitro analyses.

Fabrication, Characterization, and Emulsifying Properties of Complex Based on Pea Protein Isolate / Pectin for the Encapsulation of Pterostilbene

In this study, pectin (PEC) and pea protein isolate(PPI) was successfully used to create complexes as a novel delivery system for pterostilbene (PT). When the mass ratio of PEC to PPI was 0.5, the particle size and ζ-potential of PPI-PEC-PT were 119.41 ± 5.68 nm and -23.26 ± 0.61 mV, respectively, and the encapsulation efficiency (EE) of PT was 90.92 ± 2.08%. The photochemical stability of PT was enhanced after encapsulation. The results of the molecular docking and multispectral analysis demonstrated that the PPI and PT binding was spontaneous and mostly fueled by hydrophobic interactions. The hydrophobicity of PPI was significantly decreased and the emulsification activity and emulsion stability were significantly improved after production with PEC and PT. The best emulsification impact was demonstrated by the PPI-PEC-PT complex. PPI-PEC is an effective PT delivery material, and the PPI-PEC-PT complex is a new functional emulsification material with significant potential in liquid and semi-liquid food and health products.

Cold-Active Lipases and Esterases: A Review on Recombinant Overexpression and Other Essential Issues

Cold environments characterised by diverse temperatures close to or below the water freezing point dominate about 80% of the Earth's biosphere. One of the survival strategies adopted by microorganisms living in cold environments is their expression of cold-active enzymes that enable them to perform an efficient metabolic flux at low temperatures necessary to thrive and reproduce under those constraints. Cold-active enzymes are ideal biocatalysts that can reduce the need for heating procedures and improve industrial processes' quality, sustainability, and cost-effectiveness. Despite their wide applications, their industrial usage is still limited, and the major contributing factor is the lack of complete understanding of their structure and cold adaptation mechanisms. The current review looked at the recombinant overexpression, purification, and recent mechanism of cold adaptation, various approaches for purification, and three-dimensional (3D) crystal structure elucidation of cold-active lipases and esterase.

Combining in silico and in vitro approaches to identify endogenous hypoglycemic peptides from human milk

Potential endogenous hypoglycemic peptides derived from breast milk were screened by in silico approaches against intestinal glucose absorption- and metabolism-related membrane proteins (i.e., SGLT1, ATPase, and GPR40), and their inhibitory...