Breast cancer cells (right) spread toward the hindlimb bone (left), using the host's own bone-destroying cells (osteoclasts) to continue their advance
Breast cancer cells (right) spread toward the hindlimb bone (left), using the host's own bone-destroying cells (osteoclasts) to continue their advance © Yibin Kang, Princetown University

Small bits of genetic material fight cancer’s spread

A class of molecules called microRNAs may offer cancer patients two ways to combat their disease.

Researchers at Princeton University, New Jersey in the United States, have found that microRNAs (small bits of genetic material capable of repressing the expression of certain genes) may serve as both therapeutic targets and predictors of metastasis, or a cancer’s spread from its initial site to other parts of the body.

MicroRNAs are specifically useful for tackling bone metastasis, which occurs in about 70% of patients with late-stage cancer, said senior author Yibin Kang. During bone metastasis, tumours invade the bone and take over the cells known as osteoclasts that normally break down old bone material as new material grows. These cells then go into overdrive and dissolve the bone far more quickly than they would during normal bone turnover, which leads to bone lesions, bone fracture, nerve compression and extreme pain.

MicroRNAs can reduce that forced labour by inhibiting osteoclast proteins and thus limiting the number of osteoclasts present. The study observed that bones exhibiting metastasis developed significantly fewer lesions when injected with microRNAs. Their findings suggest that microRNAs could be effective treatment targets for tackling bone metastasis and also may help doctors detect the cancer’s spread to the bone, Kang said. Samples collected from human patients revealed a strong correlation between elevated levels of another group of microRNAs and the occurrence of bone metastasis, the researchers found.

Kang said he ultimately hopes to extend mice experimentation to clinical trials. “In the end, we want to help the patients,” he said.

The research was part-funded by the European Research Council and published in the journal Cancer Cell.