(M0930-01-03) Antiproliferative Effects of Low Level Light-Low Dose Magnetic Nanoparticle Exposure on Human Umbilical Vein Endothelial Cells

Purpose: Inhibiting the proliferation of Human Umbilical Vein Endothelial Cells (HUVECs) plays a crucial role in cancer treatment because endothelial cells are essential for angiogenesis. Additionally, inhibition of HUVEC proliferation can enhance the efficacy of chemotherapy and radiotherapy by restricting the tumor's ability to repair damaged vasculature. However, using current techniques it is extremely difficult to avoid excessive damage to normal endothelial cells in healthy tissues, which could lead to side effects like impaired wound healing or cardiovascular issues. In this work, we have introduced a novel technique by combining low level light exposure in the presence of biocompatible magnetic nanoparticles (MNPs) incurring apoptosis and inhibiting HUVEC proliferation in culture. Acute toxicity of this unique stimulation-material combination, coupled with excellent innate biocompatibility may be extremely relevant to develop anti-angiogenic strategies in oncology.

Methods: Highly water dispersible magnetic colloidal nanocrystal clusters in dextran were synthesized. For proliferation evaluation, primary HUVEC cells were routinely cultured for 72 hours, and then exposed to the MNP suspended (0 – 100 µg/mL) serum reduced culture media for four days. Cells were exposed to low intensity LED irradiation (650 nm, 20 mJ/cm²) for four hours. The treatment was repeated four times for every 24hr. Cultures were fixed in 4.0% paraformaldehyde and 2.0% gluteraldehyde in PBS. Upon fixation, for cell density assessment, bright-field images (4-5 images/condition/experiment) were captured through a 10X objective on a Vee Gee Vanguard 1491 INi inverted microscope. Nuclear morphology was assessed using confocal images captured through a 64X objective from cells labeled with 4’,6-diamidino-2-phenylindole (DAPI, Ex=405 nm, Em=450/35 nm). All cellular experiments were performed in triplicates.

Results: The designed dextran covered MNPs were externally tunable and internalized efficiently by the HUVEC cells. Live/Dead assays indicated that the toxicity was far less than bare or DMSA coated magnetic nanoparticles reported earlier (similar to the positive control conditions) and nuclear morphology was similar to that in cells not exposed to the MNPs. The low intensity LED irradiation did not impact the viability and the proliferation of the HUVECs; however severely affected the viability and the proliferation at a MNP concentration as low as 50µg/mL. The cellular and nuclear morphology indicated induction of apoptosis following the LED-MNP exposure.

Conclusion: We interpret this data to indicate that the designed dextran covered MNPs up to a concentration of 100µg/mL, and the low intensity optical irradiation, acting separately do not adversely affect cellular health of the HUVECs in the culture media. However, this unique stimulation-material combination is capable of producing severe anti-proliferative effects on the same cellular model. Since HUVEC proliferation inhibition helps cancer treatment by disrupting angiogenesis, thereby starving tumors, preventing metastasis, and enhancing the effectiveness of other front-line therapies, this novel approach carries the potential to become a highly effective strategy to suppress tumor angiogenesis, growth, and metastasis.

Acknowledgements: This work was supported by grants from the National Science Foundation (NSF) USA Award Number:2301688 (SG), Southeast Grants and Research Funding Committee (GRFC), Southeast Missouri State University (SG), Missouri, USA.


Primary HUVEC Proliferation Under Different Treatment Conditions: Control, MNP, Optical, and Optical-MNP Combined