Lapatinib loaded exosomes as a drug delivery system in breast cancer

Nanocarriers and nanoparticles in the drug delivery systems increase the drug & rsquo;s effectiveness due to their permeability and retention properties to tumor tissues. Exosomes are small extracellular natural vesicles released from the plasma membrane and they promise drug delivery vehicles to be used in anti-cancer therapy. The prominent features of exosomes as nanocarriers are biocompatibility, their natural form, high stability, and low toxicity. These features also distinguish the exosome from synthetic nanoparticles. Exosomes were isolated from healthy epithelial breast cells (MCF10 A) using an aqueous two-phase system (ATPS). Isolated exosomes were characterized with NTA (Nanoparticle Tracking Analysis), Zeta sizer, AFM (Atomic Force Microscopy), and flow cytometry. Lapatinib chemotherapeutic drug was loaded into isolated exosomes with the electroporation method. The loaded drug was characterized and measured using high-performance liquid chromatography (HPLC). The cytotoxicity of free lapatinib (Lap), lapatinib encapsulated exosome (LapExo), and empty exosome (Exo) were determined in HER2 positive breast cancer SKBR 3 and healthy breast MCF10 A cells. Lapatinib-loaded exosomes significantly reduced cellular proliferation of SKBR 3 cells at lower doses compared to free Lap treatment. Apoptosis analysis showed that LapExo treatment led to a high apoptotic rate in comparison to free Lap treatment on SKBR 3 cells. Lapatinib targeting mechanisms through the downstream components of HER2 and EGFR signaling pathway were evaluated post Lap and LapExo treatment on breast cancer SKBR-3 and healthy MCF10 A cells. LapExo treatment showed similar effect on mRNA expression and protein levels as Lap treatment. This indicates that exosomal loading and delivery of chemotherapeutic drugs did not interfere the acting mechanism of drug. In the present study, we successfully loaded lapatinib chemotherapeutic drugs in exosomes that derived from non-cancerous epithelial breast cells. The lapatinib-loaded exosomes allowed us to use the lower dose concentration of the drug for breast cancer treatment. They increased the effectiveness of drug compared to lapatinib alone. Overall, this study revealed that using of exosome natural vesicles in drug delivery approaches enable cancer therapy to be more effective and could enhance the therapeutic index of chemo-therapeutic drugs.