In collaboration with Shinshu University, the researchers at AIST developed a nanocomposite containing an osteoclast inhibitor. The nanocomposite increased the effect of the inhibitor, and it will contribute to the treatment of metastatic bone tumors.

Healthy bone is maintained through the balanced effects of osteoblasts that make bone and osteoclasts that dissolve and absorb bone (bone resorption). On the other hand, when cancer cells reach the bone and proliferate to form metastatic bone tumors, osteoclasts are activated and bone resorption progresses, causing a substantial decline in the patient’s quality of life, such as bone becoming brittle, resulting in fractures and intense pain. In addition, proteins promoting bone tumors are released from the damaged bones.

In cases of metastatic bone tumor, it is expected that suppressing osteoclast proliferation would improve the quality of life of patients by reducing bone destruction and relieving pain.

In order to increase the effect of ibandronate, an osteoclast inhibitor, the researchers prepared a new osteoclast inhibitor-containing nanocomposite by loading ibandronate onto carbon nanohorn using calcium phosphate as a mediator. The nanocomposite suppressed osteoclast proliferation with a smaller quantity than ibandronate used alone. The researchers believe that the nanocomposite will contribute to the treatment of a metastatic bone tumor.

The researchers are planning to verify the effects with animal studies and optimize the structure and composition of the osteoclast inhibitor-containing nanocomposite, improving it so that it is more efficiently taken up by osteoclasts. The researchers also plan to improve the treatment effect by considering the types of bisphosphonates for clinical applications.