royal jelly-derived exosomes synergizes the cytotoxicity of doxorubicin on hepg2 human hepatocellular carcinoma cells

Liver cancer is the fifth most frequently diagnosed cancer in men and the seventh in women. hepatocellular carcinoma (hcc) has also been noted as the third leading cause of cancer-related mortality1,2. royal jelly (rj), produced by the hypo-pharyngeal and mandibular salivary glands of young nurse honey bees, is a highly nutritious substance. due to its rich composition of bioactive compounds, including polyphenols, proteins, lipids, carbohydrates, and minerals, rj exhibits a wide range of pharmacological properties, such as anti-cancer effects3,4. the anti-cancer effects of royal jelly (rj) on hepg2 cells, with apoptosis induction through multiple pathways identified as the primary mechanism behind its cytotoxicity, have been proven5. doxorubicin (dox) is an effective antitumor drug for treating human liver cancer, but excessive doses can cause significant side effects in clinical use6. on the other hand hcc resists chemotherapy due to the expression of multidrug-resistant (mdr) transporters and while dox is often used for intra-hepatic artery chemotherapy in hcc, its effectiveness is low, showing minimal impact on tumor reduction and overall survival 7. the aim of this study is to investigate the synergistic effects of rj-derived exosomes (rjexo) in combination with doxorubicin (dox) on hepg2 cells. for this purpose, exosomes were isolated from fresh rj obtained from the city of urmia using the precipitation method. in order to quantitatively evaluate exosomes, the total protein content was measured using the bradford method. the cytotoxicity of dox and rjexo at concentrations of 1 mg/ml of total protein for rjexo and 25 µg/ml for dox, both individually and in co-administration, was evaluated on hepg2 cells using the mtt assay. although rjexo and dox at the mentioned concentrations were able to significantly (p < 0.005) reduce cell viability in hepg2, dox showed a greater ability in this regard. interestingly, their co-administration further reduced cell viability, indicating their synergistic effects.