Human Cord Blood-Derived Exosomes Enhance Chemosensitivity in Acute Myeloid Leukemia: A Promising Therapeutic...

Acute myeloid leukemia (AML) arises from the aberrant proliferation of white blood cells, red blood cells, or platelets. Various therapy modalities are available for individuals diagnosed with AML. While Cytarabine remains a standard treatment, exosomes, especially those derived from cord blood, have emerged as promising adjuncts. Exosomes are a specific kind of extracellular vesicles that have been identified as candidate biomolecules for the treatment of AML. The current study looked at how cord blood-derived exosomes affect the U937 cell lines compared to Cytarabine as a fundamental component of standard AML treatment.

The first stage involved processing umbilical cord blood and isolating the mononuclear cells, CB-MNCs. The exosomes were isolated and verified using transmission electron microscopy, western blotting, and dynamic light scattering. Subsequently, for 72 hours, the U937 cells were cultivated and exposed to the exosomes, Cytarabine, and a combination of both. Afterward, apoptosis was evaluated using flow cytometry. The activity of Caspase 3/7 was assessed using a special kit. The real-time PCR technique was used to evaluate the gene expression in the proliferation and apoptosis pathways. Finally, the activity of NF-κB and AMPK was assessed using western blotting.

The flowcytometry analysis showed that the apoptosis rate of U937 cells after being exposed to CB-MNC exosomes, Cytarabine, and a mix of them was 19.60 (p < 0.05) %, 44.05 % (P < 0.0001), and 47.45 % (P < 0.0001), respectively. The activity of Caspase 3-7 was 0.32 mU/mL and 0.45 mU/mL (P < 0.001) Cytarabine and Mix groups. The qRT-PCR study revealed a notable upregulation of apoptotic genes and a downregulation of anti-apoptotic gene expression in the Mix group. Western blot analysis revealed a decrease in NF-κB phosphorylation in all treatment groups. In addition, the phosphorylation of AMPK increased in all treatment groups.

The study evaluated the effects of CB-MNC-derived exosomes on U937 cells, both alone and in combination with Cytarabine. Results demonstrated that while exosomes induced moderate apoptosis, their combination with Cytarabine significantly enhanced cell death, increased Caspase 3/7 activity, and altered gene expression in favor of apoptosis. The treatment also inhibited NF-κB and activated AMPK signaling pathways.

In conclusion, our findings indicated that CB-MNCs-derived exosomes together with Cytarabine have a cooperative effect on U937 cells through increasing apoptosis rate and reducing the proliferation rate, and may serve as a promising adjunct in AML therapy.