One-step simultaneous liquid phase exfoliation-induced chirality in graphene and their chirality-mediated microRNA delivery

Graphene (G) has established itself as an exciting prospect for a broad range of applications owing to its remarkable properties. Recent innovations in chiral nanosystems have led to sensors, drug delivery, catalysis, etc. owing to the stereospecific interactions between various nanosystems and enantiomers. As the molecular structure of G itself is achiral introducing chirality in G by simple attachment of a functional group (a chiral ligand) on the G nanosheet may result in more diverse applications. Herein, we demonstrate direct liquid phase exfoliation and chiral induction in G nanosheets abbreviated as L-graphene and D-graphene in the presence of chiral L-tyrosine and D-tyrosine and by applying high-temperature sonication. The obtained exfoliated nanosheets demonstrated stable chirality confirmed by circular dichroism. Fourier transform infrared (FTIR) spectra, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC) showed functional, structural, morphological, surface, and thermal characteristics of L-graphene and D-graphene. The hemo-compatibility of these chiral graphenes was evaluated for the very first time utilizing human red blood cells. Lastly, for the very first time, an attempt was made to explore enantiomeric binding between chiral L-graphene and D-graphene with microRNA (miR-205) and their possibility towards chirality-mediated gene delivery in prostate cancerous cells

Piperlongumine nanoformulation attenuates pancreatic tumor desmoplasia and alter tumor immune responses

Pancreatic cancer (PanCa) is characterized by lack of early diagnosis, poor response to available therapeutic modalities and chemoresistance. Gemcitabine (GEM) is currently considered the most effective therapy for PanCa; however, it shows only a marginal survival benefit of 6 months. This poor drug response has been attributed to desmoplasia, causes suboptimal drug delivery, alters tumor microenvironment (TME), which includes tumor surrounding blood vessels, fibroblasts, immune cells, extracellular matrix, and other signaling molecules and induces chemo-resistance in tumors. To overcome these existing issues associated with chemotherapy, identification and development of novel therapeutic modalities are a pressing need. Piperlongumine (PL) is a natural alkaloid isolated from the long pepper, Piper longum L., and has shown substantial cancer-preventive and therapeutic efficacy against a variety of cancers. However, delivering its effective concentration in pancreatic tumors has been challenging. We have recently engineered a multi-layered Pluronic F127 and polyvinyl alcohol stabilized, and poly-L-lysine coated piperlongumine loaded poly(lactic-co-glycolic acid) nanoparticle formulation (PLGA-PL), which effectively inhibits the growth of PanCa cells. In this study, we demonstrate that PLGA-PL effectively sensitizes tumor cells to GEM via decreased desmoplasia, altered TME, SHH/CXCL12/CXCR4 and immune surveillance. Our finding show that PLGA-PL synergizes with GEM in inhibiting PanCa cell (HPAF-II and Panc-1) growth, migration, and invasion compared to free PL. Mechanistically, PLGA-PL targets the TME via inhibition of sonic hedgehog (SHH) pathway and oncogenic CXCR4/CXCL12 signaling axis that inhibits bidirectional tumor-stromal cells interaction. We have also found that PLGA-PL alone and in combination with GEM targets cancer stem cells by inhibiting pluripotency maintaining stemness factors (Nanog, Sox2, c-Myc, CD133, and Oct-4) as determined by qRT-PCR, Western blotting, and immunofluorescence analysis, and further confirmed by restricting tumor sphere formation. Furthermore, PLGA-PL also effectively targets tumor-associated macrophages (TAM) by repolarizing M2 into M1 phenotype via inhibiting expression of M2 markers and an increase in M1 markers in mouse macrophage cell line RAW264.7. M2 polarization of RAW264.7 cells were induced by culture with IL-4 (20 ng/mL) in presence of PLGA-PL or vehicle control. In addition, PLGA-PL effectively increases phagocytic capacity in murine macrophages as determined by phagocytosis assay (Vybrant Phagocytosis Assay Kit). In conclusion, we observed that PLGA-PL effectively targets TME, facilitates GEM uptake by inhibiting the activation of CXCR4/CXCL12/SHH signaling, and reprograming the tumor immune surveillance. This study suggests that PLGA-PL has great potential for future clinical use in management of PanCa