Shikonin inhibited glycolysis and sensitized cisplatin treatment in non-small cell lung cancer cells via the exosomal pyruvate kinase M2 pathway.

The active ingredient of the traditional Chinese medicine comfrey is shikonin, a naphthoquinone compound. The focus of this study was to investigate the effect of shikonin on the proliferation, invasion, migration, and chemoresistance of non-small cell lung cancer (NSCLC) cells, and to explore its underlying molecular biological mechanisms. The results show that shikonin inhibited the viability, proliferation, invasion, and migration of NSCLC cells A549 and PC9, and induced apoptosis. As the inhibitor of pyruvate kinase M2 (PKM2), a key enzyme in glycolysis, shikonin inhibited glucose uptake and the production of lactate, the final metabolite of aerobic glycolysis. In vivo chemotherapeutic assay showed that shikonin reduced the tumor volume and weight in NSCLC mice model and increased the sensitivity to cisplatin chemotherapy. Histoimmunology experiments showed the combination of shikonin and cisplatin downregulated the expression of PKM2 and its transcriptionally regulated downstream gene glucose transporter 1 (Glut1) in tumor tissue. In an assessment of glucose metabolism, micro-PET/CT data showed a combination of shikonin and cisplatin inhibited the fluorodeoxy glucose (18F-FDG) uptake into tumor. Since exosomal PKM2 affected the sensitivity to cisplatin in NSCLC cells, we also demonstrated shikonin could inhibit exosome secretion and exosomal PKM2 through the administration of exosomal inhibitor GW4869. Furthermore, shikonin sensitized cisplatin treatment by reducing the extracellular secretion of exosomal PKM2. In conclusion, we suggest that shikonin not only inhibits PKM2 intracellularly but also reduces glycolytic flux and increases cisplatin sensitivity through the exosomal pathway.

Corosolic acid reduces A549 and PC9 cell proliferation, invasion, and chemoresistance in NSCLC via inducing mitochondrial and liposomal oxidative stress.

Corosolic acid is a pentacyclic triterpenoid isolated from Lagerstroemia speciosa, which is known to inhibit cancer cell proliferations. Whereas, the role of this compound on non-small cell lung cancer (NSCLC) cells still largely unclear. So, the aim of this study was to reveal the regulatory mechanism of corosolic acid to NSCLC. Here, we cultured A549 and PC9 cells in increasing corosolic acid concentrations, as well as treated mice with a physiologically relevant concentration of the compound, and used metabolomics analysis and high-throughput sequencing to examine its influences on cell invasion and proliferation, chemoresistance, and metastasis. We found that corosolic acid inhibited cell invasion and proliferation in vivo and in vitro, as well as increase the chemosensitivity of both cell types to cisplatin. Furthermore, we found that corosolic acid destabilized the glutathione peroxidase 2-mediated redox system, which increased mitochondrial and liposomal oxidative stress. Corosolic acid also decreased the targeting protein for TPX2 level, which inhibited PI3K/AKT signaling and induced apoptosis. In addition, the accumulation of reactive oxygen species dissociated the CCNB1/CDK1 complex and induced G2/M cell cycle arrest. Taken collectively, the data indicate that corosolic acid reduces NSCLC cell invasion and proliferation, as well as chemoresistance, by inducing mitochondrial and liposomal oxidative stress.

In Situ Surface Modification of Microfluidic Blood-Brain-Barriers for Improved Screening of Small Molecules and Nanoparticles.

Here, we have developed and evaluated a microfluidic-based human blood-brain-barrier (µBBB) platform that models and predicts brain tissue uptake of small molecule drugs and nanoparticles (NPs) targeting the central nervous system. By using a photocrosslinkable copolymer that was prepared from monomers containing benzophenone and N-hydroxysuccinimide ester functional groups, we were able to evenly coat and functionalize µBBB chip channels in situ, providing a covalently attached homogenous layer of extracellular matrix proteins. This novel approach allowed the coculture of human endothelial cells, pericytes, and astrocytes and resulted in the formation of a mimic of cerebral endothelium expressing tight junction markers and efflux proteins, resembling the native BBB. The permeability coefficients of a number of compounds, including caffeine, nitrofurantoin, dextran, sucrose, glucose, and alanine, were measured on our µBBB platform and were found to agree with reported values. In addition, we successfully visualized the receptor-mediated uptake and transcytosis of transferrin-functionalized NPs. The BBB-penetrating NPs were able to target glioma cells cultured in 3D in the brain compartment of our µBBB. In conclusion, our µBBB was able to accurately predict the BBB permeability of both small molecule pharmaceuticals and nanovectors and allowed time-resolved visualization of transcytosis. Our versatile chip design accommodates different brain disease models and is expected to be exploited in further BBB studies, aiming at replacing animal experiments.