Exosomes, biogenic nano-vesicles, are renowned for their ability to encapsulate diverse payloads, however the systematic development and validation of exosomal formulation with significant biological implications have been overlooked. Herein, we developed and validated Exo-DTX, a QbD-driven optimized RAW 264.7 cell derived exosomal anti-cancer formulation of docetaxel (DTX) and evaluate its anti-metastatic and apoptotic efficacy in TNBC 4T1 cells. RAW264.7-derived exosomes were having particle size (112.5 +/- 21.48 nm) and zeta-potential (-10.268 +/- 3.66 mV) with polydispersity (PDI:0.256 +/- 0.03). The statistical optimization of exosomes (200 mu g) with Exo: DTX ratio 4:1 confirmed encapsulation of 23.60 +/- 1.54 ng DTX/ mu g exosomes. Exo-DTX (-189 nm, -11.03 mV) with 100 ng/ml DTX as payload exhibited -5 folds' improvement in IC50 of DTX and distinct cytoskeletal deformation in TNBC 4T1 cells. It also has shown enormous Filamentous actin (F-actin) degradation and triggered apoptosis explained Exo-DTX's effective anti-migratory impact with just 2.6 +/- 6.33 % wound closure and 4.56 +/- 1.38 % invasion. The western blot confirmed that Exo-DTX downregulated migratory protein EGFR and beta 1-integrin but raised cleaved caspase 3/caspase 3 (CC3/C3) ratio and BAX/BCL-2 ratio by about 2.70 and 4.04 folds respectively. The naive RAW 264.7 exosomes also contributed positively towards the effect of ExoDTX formulation by suppressing beta 1-integrin expression and increasing the CC3/C3 ratio in TNBC 4T1 cells as well. Additionally, significant improvement in PK parameters of Exo-DTX was observed in comparison to Taxotere, 6-folds and 3.04-folds improved t1/2 and Vd, proving the translational value of Exo-DTX formulation. Thus, the Exo-DTX so formulated proved beneficial in controlling the aggressiveness of TNBC wherein, naive exosomes also demonstrated beneficial synergistic anti-proliferative effect in 4T1.

A novel core–shell nanocarrier system has been designed for co-delivery of a small anticancer drug, docetaxel (DTX) and tumor suppressor (TS) miR-34a named as Exo(PAN34a+DTX). The core is formed by pH dependent polyamine salt aggregates (PSA) containing both the payloads and the shell is formed by RAW 264.7 cell derived exosomal fragments. Herein, phosphate driven polyallylamine hydrochloride (PAH, MW:17,500 Da) PSA was formed in presence of miR-34a and DTX to form PAN34a+DTX. The formulation exhibited pH dependent DTX release with only 33.55 ± 2.12% DTX release at pH 7.2 and 75.21 ± 1.8% DTX release till 144 h at pH 5.5. At 1.21 molar ratio of phosphate to the amine (known as R value), efficient complexation of miR-34a (3.6 μM) in the PAN particles was obtained. PAN34a+DTX demonstrated particle size (163.86 ± 12.89 nm) and zeta-potential value of 17.53 ± 5.10 mV which upon exosomal fragment layering changed to − 7.23 ± 2.75 mV which is similar to the zeta-potential of the exosomal fragments, i.e., − 8.40 ± 1.79 mV. The final formulation Exo(PAN34a+DTX), loaded with 40 ng/mL DTX and 50 nM miR-34a exhibited 48.20 ± 4.59% cytotoxicity in triple negative breast cancer (TNBC) cells, 4T1. Co-localization of CM-DiI (red fluorescence) stained exosomal fragments and FAM-siRNA (green fluorescence) in the cytoplasm of 4T1 cells after 6 h of Exo(PANFAM) treatment confirmed the efficiency of the designed system to co-deliver two actives. Exo(PAN34a+DTX) also reduced BCL-2 expression (target gene for miR-34a) by 8.98 folds in comparison to free DTX confirming promising co-delivery and apoptosis inducing effect of Exo(PAN34a+DTX) in 4T1.

Aim: Exosomes, as a nanocarrier for the co-delivery of biologicals and small anticancer molecules is yet in its infancy. Herein, we investigated hUCBMSC derived exosomes as a biogenic nanocarrier for the co-delivery of tumor suppressor miR-125a and microtubule destabilizing Docetaxel (DTX) to target the proliferative and migratory aggressiveness of the murine TNBC 4T1 cells. Main methods: In this study, hUCBMSCs from the human umbilical cord blood cells (hUCB) were successfully transfected with miR-125a. Thereafter, DTX was encapsulated into both non-transfected and transfected exosomes by optimized mild sonication-incubation technique. The anticancer efficiency of hUCBMSC Exo-DTX and miR-125a Exo-DTX was compared by MTT and morphometric assay. The prominent anti-metastatic behaviour of the latter was confirmed by in-vitro wound healing and transwell invasion assay. Further, the synergistic effect of miR-125a and DTX was confirmed by F-actin and nuclear degradation by confocal and FESEM assay. Key findings: hUCBMSC exosomes exhibited DTX payload of 8.86 & PLUSMN; 1.97 ng DTX/ & mu;g exosomes and miRNA retention capacity equivalent to 12.31 & PLUSMN; 5.73 %. The co-loaded formulation (miR-125a Exo-DTX) exhibited IC50 at 192.8 ng/ml in 4T1 cells, which is almost 2.36 folds' lower than the free DTX IC50 (472.8 ng/ml). Additionally, miR-125a Exo-DTX treatment caused wound broadening upto 6.14 & PLUSMN;0.38 % while treatment with free DTX and miR-125a exosomes alone caused 18.71 & PLUSMN;4.5 % and 77.36 & PLUSMN;10.4 % of wound closure respectively in 36 h. miR125a Exo-DTX treatment further exhibited significantly reduced invasiveness of 4T1 cells (by 3.5 & PLUSMN; 1.8 %) along with prominent cytoskeletal degradation and nuclear deformation as compared to the miR-125a exosomes treated group. The miR-125a expressing DTX loaded exosomal formulation clearly demonstrated the synergistic apoptotic and anti-migratory efficiency of the miR-125a Exo-DTX. Significance: The synergistic anticancer and anti-metastatic effect of miR-125a Exo-DTX was observed due to presence of both DTX and miR-125a as the cargo of hUCBMSC derived exosomes.

"Cancer" is a dreadful immune-pathological condition that is characterized by anti-inflammatory and tumorigenic responses, elicited by the infiltrating immune cells in the vicinity of an uncontrollably proliferative tumor in the tumor microenvironment (TME). The TME offers a conducive microenvironment that supports cancer cell survival by modulating the host immune defense. Recent advancement in exosomal research has shown exosomes, originating from immune cells as well as the cancer cells, have immense potential for suppressing cancer progression and survival in the TME. Additionally, exosomes, irrespective of their diverse sources, have been reported to be efficient nanocarriers for cancer therapeutics with the ability for targeted delivery due to their biogenic nature, ease of cellular uptake, and scope for functionalization with biomolecules like peptides, aptamers, targeting ligands, etc. Immune cell-derived exosomes per se have been found efficacious against cancer owing to their immune-stimulant properties (in either naive or antigen primed form) even without loading any of cancer therapeutics or targeting ligand conjugation. Nevertheless, exosomes are being primarily explored as nanovesicular carriers for therapeutic molecules with different loading and targeting strategies, and the synergism between immunotherapeutic behavior of exosomes and the anticancer effect of the therapeutic molecules is yet to be explored. Hence, this review focuses specifically on the possible strategies to modulate the immunological nature of the source immune cells to obtain immune stimulant exosomes and bring these into the spotlight as chemo-immunotherapeutic nanovesicles, that can easily target and modulate the TME.

Exosomes are natural nanovesicles excreted by many cells for intercellular communication and for transfer of materials including proteins, nucleic acids and even synthetic therapeutic agents. Surface modification of exosomes imparts additional functionality to the exosomes to enable site specific drug delivery and in vivo imaging and tracking and is an emerging area in drug delivery research. The present review focuses upon these modifications on the exosomal surface, the chemistry involved and their impact on targeted drug delivery for the treatment of brain, breast, lung, liver, colon tumors and, heart diseases and for understanding their in vivo fate including their uptake mechanisms, pharmacokinetics and biodistribution. The specific exosomal membrane proteins such as tetraspanins (CD63, CD81, CD9), lactadherin (LA), lysosome associated membrane protein-2b (Lamp-2b) and, glycosyl-phosphatidyl-inositol (GPI) involved in functionalization of exosome surface have also been discussed along with different strategies of surface modification like genetic engineering, covalent modification (click chemistry and metabolic engineering of parent cells of exosomes) and non-covalent modification (multivalent electrostatic interactions, ligand-receptor interaction, hydrophobic interaction, aptamer based modification and modification by anchoring CP05 peptide) along with optical (fluorescent and bioluminescent) and radioactive isotope labelling techniques of exosomes for imaging purpose.

The study summarizes the development of an orally active nanoformulation of a potent but one of the least explored molecules, lisofylline (LSF), in type 1 diabetes (T1D). LSF undergoes rapid metabolism, resulting in poor oral bioavailability and short half-life. In this work, to improve its pharmacokinetic (PK) properties, LSF was encapsulated in the form of its ester prodrug [LSF-linoleic acid (LA) prodrug] into biodegradable self-assembling polymeric micelles [LSF-LA PLM, size: 149.3 nm; polydispersity index: 0.209; critical micelle concentration (cmc); 5.95 μg/mL and Nagg: 14.82 at 10 cmc] of methoxypoly(ethylene glycol)-b-poly(carbonate-co-l-lactide) (mPEG-b-P(CB-co-LA)) block copolymer. LSF-LA PLM was found to be equally effective as the LSF-LA prodrug in cell culture studies in insulin-secreting MIN6 cells and showed excellent stability in simulating biological fluids and plasma. PK of LSF-LA PLM (10 mg/kg dose) revealed a significant improvement in oral bioavailability of LSF (74.86%; 3.3-fold increase in comparison to free LSF) and drastic reduction in the drug metabolism. Further, LSF-LA PLM showed a significant reduction in fasting glucose levels and increase in insulin levels by intraperitoneal as well oral routes in a streptozotocin (STZ)-induced T1D rat model. Production of inflammatory cytokines (TNF-α and IFN-γ) and different biochemical markers for liver and kidney functions were much reduced in diabetic animals after treatment with LSF-LA PLM. LSF-LA PLM-treated pancreatic sections showed minimal infiltration of CD4+ and CD8+ T-cells as indicated by hematoxylin/eosin staining and immunohistochemical analysis.