Mechanistic Insights into Xanthohumol-induced Apoptosis and Cytokine Modulation in Multiple Myeloma with a Focus on Nanoparticle Targeting Strategies
Date of Award
5-2024
Degree Type
Thesis
Degree Name
Master of Science in Biomedical Sciences
First Advisor
Xinyu (Eric) Wang, Ph.D.
Second Advisor
Shu Zhu, MD, Ph.D.
Third Advisor
Yujin Kim, PharmD, Ph.D.
Fourth Advisor
Yuancheng Li, Ph.D.,
Abstract
Multiple myeloma (MM) is characterized by a malignancy of terminally differentiated B lymphocytes within the bone marrow microenvironment (BME). The BME fosters the proliferation of MM cells and enhances their resistance to standard treatments, notably by releasing the soluble factors Interleukin-6 (IL-6) and vascular endothelial growth factor. The mechanism by which Xanthohumol (XN), a prenylated flavonoid found in hops (Humulus Lupulus), exerts pro-apoptotic and cytokine-inhibitory activity in MM cells has yet to be elucidated. Cytotoxic activity of XN was evaluated within the cell culture of MM cell line RPMI 8226 via presto blue assay. The pro-apoptotic effects of XN were examined by western blot analysis of RPMI 8226 cell lysates. Additionally, the inhibitory effect of XN on the activity of cytokines secreted by Human Stromal Cells (HS5) and MM cells (RPMI 8226) was investigated using a transwell model, with the cytokine levels in the culture media quantified by ELISA. XN induced dose- and time-dependent decrease of cell viability in RPMI 8226 cells with an IC50 of 32.9 µM at 48 hours and 11.1 µM at 72 hours, respectively. Western blot analysis of cell lysates after 24 hours of treatment with XN indicated a dose-dependent increase in pro-apoptotic protein cleaved Caspase3 as well as downstream cleavage of PARP1. Lastly, ELISA analysis of IL-6 within cell media indicated a dose-dependent decrease of IL-6 with an IC50 of 8.67 µM. Our findings support the proposed anti-myeloma potential of XN by showcasing its dual function as a pro-apoptotic agent as well as its ability to reduce cytokine release within a simulated in vitro BME. The significant reduction in IL-6 levels suggests XN's capability to disrupt the cytokine interaction within the BME, which is crucial for MM progression. In addition, we prepared RGD-conjugated ultrafine iron oxide nanoparticles (RGD-µIONPs) loaded with XN for targeted MM therapy. The RGD motif, a tripeptide consisting of arginine-glycine-aspartic acid, was employed to facilitate the specific binding of nanoparticles to αvβ3 integrins overexpressed on MM cells. To characterize the nanoparticle delivery system, we assessed the hydrodynamic size measured by dynamic light scattering (DLS), zeta potential, and the morphology through transmission electron microscopy (TEM). Our results indicate that XN was successfully loaded into the RGD-µIONPs. Further investigation will be conducted to evaluate the effects of RGD- µIONP/XN on MM cell growth and cytokine inhibition compared to those of XN alone.
Recommended Citation
Pruner, Joshua, "Mechanistic Insights into Xanthohumol-induced Apoptosis and Cytokine Modulation in Multiple Myeloma with a Focus on Nanoparticle Targeting Strategies" (2024). PCOM Biomedical Studies Student Scholarship. 234.
https://digitalcommons.pcom.edu/biomed/234