Study stating the application of hydroxyapatite nanoparticles; in tumor associating the bone segmental defect. Materials scientists widely incorporate hydroxyapatite for bone repair in bone tissue engineering due to its superior biocompatibility as a natural component of human bones and teeth. Study highlighting the proliferation suppressive effect of HA nanoparticles against a variety of cancer cells by combining the translational value of n-HA as a bone-regenerating material and an anti tumor agent.
Based on the results, the study verifying the ability of the n-HA releasing scaffold to suppress tumor growth and osteolytic lesion while promoting bone regeneration. The research findings provide a strong rationale to use n-HA to regenerate tumor-associated bone segmental defects. Approximately 2,500 new cases of primary bone cancer are diagnosed annually with approximately half the patients exhibiting bone metastasis.
Application of hydroxyapatite nanoparticles
During standard clinical treatment of bone cancers, the surgical approach includes resection and reconstruction of the affected bone, followed by adjuvant radiation or chemotherapy. Although load-bearing artificial implants are currently adopted in clinical practice, poor implant bone osseointegration and the difficulty of new bone formation in a tumor environment remain major challenges for orthopedic surgeons. Incomplete surgical resection of the affecting tissue can also risk the spread of tumor cells to result in 8% recurrence or metastases.
Notable research studies have shown the capacity of n-HA to inhibit cancer cell; proliferation and induce apoptosis, including osteosarcoma cells, breast cancer cells; colon cancer cells and liver cancer cells, while sparing normal cells. The scientists harvested the tumor samples at week 4 to confirm the antitumor ability of n-HA; using histological staining at the interface of the tumor and muscle tissue. They noted diverse immune cells surrounding the n-HA particles; such immune diversity was not observing surrounding µ-HA and n-TiO2 coated scaffolds.
Prevention of metastasis
Using TEM observations, Zhang et al. showing both n-HA and n-TiO2 internalized within tumor cells. Histological findings at week 4 indicating the prevention of metastasis to the lung with n-HA animal groups; although similar observations were not recording with µ-HA or n-TiO2. Metastasis elimination in rabbits treated with n-HA led to longer survival rates; and lower rates of tumor positive cells compared to those treated with other materials.
The scientists then completed wound healing assays; to identify if secretory inflammatory cytokines such as TNFα (Tumor Necrosis Factor Alpha) were releasing from the macrophages; as a result of n-HA stimulation to inhibit tumor cell migration. They confirmed that cytokine secretion by macrophages upon stimulation with n-HA could decrease tumor cell migration.