Discovering a Racemate Polycyclic Prenylated Acylphloroglucinol with Unprecedented Skeleton by an ESI-LCMS Analytical Approach

By an ESI-LC/MS analytical method, a racemate 1 consisting of a pair of unprecedented phloroglucinol enantiomers with a 5/6/5/5/6 fused ring system, (−)-garcinielliptone HG [((−)-1a] and (+)-garcinielliptone HH [(+)-1b], was obtained from the isolates of a CH2Cl2 extract of Garcinia subelliptica (heartwood). The gross structure of 1 was elucidated by spectroscopic methods and X-ray single-crystal diffraction data. The absolute configurations of 1a and 1b were unequivocally assigned by analysis on the calculated and experimental circular dichroism spectra and X-ray single-crystal diffraction data

Glucose Transporter 1‑Mediated Transcytosis of Glucosamine-Labeled Liposomal Ceramide Targets Hypoxia Niches and Cancer Stem Cells to Enhance Therapeutic Efficacy

Tumour hypoxia plays an important role in modulating tumorigenesis, angiogenesis, invasion, immunosuppression, resistance to treatment, and even maintenance of the stemness of cancer stem cells (CSCs). Moreover, the targeting and treatment of hypoxic cancer cells and CSCs to reduce the influence of tumor hypoxia on cancer therapy remains an imperative clinical problem that needs to be addressed. Since cancer cells upregulate the expression of glucose transporter 1 (GLUT1) through the Warburg effect, we considered the possibility of GLUT1-mediated transcytosis in cancer cells and developed a tumor hypoxia-targeting nanomedicine. Our experimental results indicate that glucosamine-labeled liposomal ceramide can be efficiently transported between cancer cells by GLUT1 transporters and substantially accumulated in the hypoxic area in in vitro CSC spheroids and in vivo tumor xenografts. We also verified the effects of exogenous ceramide on tumor hypoxia, including important bioactivities such as upregulation of p53 and retinoblastoma protein (RB), downregulation of hypoxia-inducible factor-1 alpha (HIF-1α) expression, disruption of the OCT4-SOX2 network of stemness, and inhibition of CD47 and PD-L1 expression. To achieve an ideal therapeutic outcome, we combined treatment of glucosamine-labeled liposomal ceramide with paclitaxel and carboplatin, and we found an excellent synergistic effect, with tumor clearance being noted in three-fourths of the mice. Overall, our findings provide a potential therapeutic strategy for the treatment of cancer