Fig. 6. Increased drug bioavailability and enhanced anti-cancer effects.

(A) Antiproliferative activity of drug-loaded milk exosomes versus free drugs [withaferin A (WFA) and paclitaxel (PAC)] in human lung cancer A549 cells. For Exo-drug treatments, exosomal protein concentration was maintained constant (50 μg/ml). (B) Anti-proliferative activity of milk exosomes per se against human lung (A549 and H1299), and breast (T47D and MDA-MB-231) cancer cells. Cells were treated with 50 μg/ml exosomal protein for 72 h. The percent cell survival was analyzed by MTT assay. Data represent average ± SD (n=3). (C) Anti-proliferative activity of milk exosomes per se at concentrations 0- 50 μg/ml for 72 h against human normal lung Beas-2b and lung cancer (A549) cells. Data represent average ± SD (n=3). (D) Following inoculation with human lung cancer A549 cells (2.5 × 10⁶ cells), when tumor xenografts grew to over 80 mm³, animals were treated i.p. three times a week with Exo-WFA (4 mg/kg WFA and 25 mg/kg b. wt.). Two other groups were treated i.p. with Exo alone (25 mg/kg b. wt.) or WFA (4 mg/kg). Data represent average ± SE (n = 6–8); SE is not shown in WFA alone for clarity. Statistical analysis was done using student's t-test; *, p < 0.05; **, p < 0.005. (E) Animals bearing A549 xenografts were treated with oral gavage three times a week with FA-Exo-WFA (8 mg/kg WFA and 25 mg/kg b. wt. exo protein) to achieve tumor targeting. Two other groups were treated with Exo alone (25 mg/kg b. wt.) or vehicle. Data represent average ± SE (n = 8–10). Statistical analysis was done using student's t-test; *, p < 0.05; **, p < 0.005.