Novel nanomedicine could keep cancer cells dormant

Researchers have developed a novel therapeutic approach that could lead to nanomedicines tailored to maintain cancer cells in a dormant state.

In the study published in the journal ACS Nano, the researchers used mice to create model pairs of osteosarcoma tumour tissues (part "silent" cancer, part "progressive" cancer) and observed their different characteristics.

Regarded as one of the most aggressive cancers, osteosarcoma develops in the bones of children and adolescents.

"We wanted to examine what was different, because we knew that if we could understand their genesis, then we could understand what kept the tumour tissue dormant," said one of the researchers Ronit Satchi-Fainaro from Tel Aviv University in Israel.

The researchers sequenced microRNAs in the tissue and found three microRNAs that were expressed in low levels in the aggressive tumour tissue and in high levels in the dormant tumour tissue.

They then inserted the microRNA into the tumour tissues in a petri dish and observed a reduced malignant potential, demonstrated by decreased ability of the cancer cells to communicate with the normal cells present in the microenvironment.

"We saw that the osteosarcoma cells treated with the selected microRNAs were unable to recruit blood vessels to feed their growth," Satchi-Fainaro said.

"In order to keep these microRNAs stable in the blood, we needed to encapsulate them in a nanoparticle that circulates in healthy blood vessels, but that disembark and deliver the drug therapy at the leaky blood vessels that exist at tumour sites," Satchi-Fainaro explained.

The researchers designed a nanomedicine that would have a special activation method at the tumour site in the target cell.

"The mice treated with the nanomedicine lived for six months, which is the equivalent of 25-odd human years," Satchi-Fainaro reported.

"This makes us very optimistic. If we cannot teach tumour cells to be normal, we can teach them to be dormant," she said.

The researchers believe that the findings would apply to other tumour types as a universal approach to treating cancer.