Osteocyte-Osteoclast Interactions Post-Radiation: A Co-Culture Model to Investigate Bone Loss Mechanisms

Presenter: Gessica Bonheur

Faculty Sponsor: Stacyann Bailey

School: UMass Amherst

Research Area: Engineering

Session: Poster Session 6, 4:15 PM - 5:00 PM, Auditorium, A43

ABSTRACT

Radiation therapy (RT) is a frequently used treatment for many cancers, delivering high doses of local radiation to kill cancer cells and other highly proliferative cells. Due to continuous bone turnover, bone cells—including osteocytes, osteoclasts, and osteoblasts—are highly susceptible to radiation damage. Bone remodeling is maintained through coordinated signaling between these cells, balancing bone resorption and formation. Osteoclasts resorb bone enzymatically via cathepsin K secretion, while osteocytes regulate osteoclast activity by secreting osteoprotegerin (OPG) or receptor activator of nuclear factor kappa beta ligand  (RANKL) to inhibit or stimulate resorption, respectively. RT is suspected of disrupting this signaling pathway, leaving bones fragile and prone to fracture. 

To observe the impact of RT on osteoclast differentiation and activity, a direct co-culture was established. RAW 264.7 monocyte/macrophage-like cells were seeded. OCY-454 osteocyte-like cells were irradiated at 5, 10, and 15 Gy and seeded at a 2:1 ratio. Culture media was supplemented with 50 ng/mL RANKL. Irradiated OCY-454 monocultures were established to explore the effect of RT on osteocytes alone. Non-irradiated OCY-454 co-cultures and monocultures were established to serve as a control. Cultures were maintained and monitored via imaging and supernatant collection for seven days. Gene expression was assessed via qPCR, demonstrating downregulated OPG and an increased RANKL: OPG ratio, indicating less regulation of osteoclast differentiation. This culture will be performed again to generate biological replicates, quantify osteocyte death, and assess a comprehensive gene and protein expression profile. Ultimately, RT is expected to increase osteoclast activity and thus, bone resorption.

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