Modified Stem Cells Bring Anti-Cancer Drugs Directly to Malignant Tissues

One of the key difficulties in the treatment of cancer is the fact of its evolution being parallel to our own. This makes developing effective drugs a complex and on-going process.

Another challenge faced by researchers is the effective delivery of drugs directly to malignant cells without damaging healthy organs and tissues.

In recent years, a popular way of accomplishing that was through mesenchymal stem cells (MSCs), known for their ability to find and target tumour cells in the body.

Unfortunately, a number of pilot studies have eventually shown that MSCs have a limited drug loading capacity and tend to lose their ability to target malignant cells upon loading.

Engineered mesenchymal stem cells are capable of delivering anti-cancer drugs directly to malignant tumours. Image: Nick Youngson via, CC BY-SA 3.0

Now, as detailed in a study published in the Journal of Controlled Release, a group of researchers from Tokyo University of Science may have found a way to bypass this issue, transforming MSCs into potent vessels for drug delivery.

“We wondered if the answer to our dilemma of modifying mesenchymal stem cells with an anti-cancer drug was to exploit the property of mesenchymal stem cells to accumulate in tumor tissues,” said co-author Dr Kosuke Kusamori.

In the study, Kusamori and colleagues employed the widely used “avidin-biotin-complex” (ABC) method to load liposomes with the anti-cancer drug doxorubicin (DOX) and have them carry it to the surface of specific mouse MSCs.

Results showed that MSCs containing the drug-infused liposomes (named “DOX-Lips” in the study) were able to carry a significant amount of the drug directly inside mouse colon cancer cells grown in artificial lab cultures.

Once applied in a mouse model with skin and lung cancer, the method turned out to be just as effective, leading the researchers to conclude that modified MSCs could fully suppress tumour growth in mice.

“We have succeeded in developing a new targeted cancer therapy,” said co-author Makiya Nishikawa. “Mesenchymal stem cells can migrate to brain tumors and minute cancer lesions that are otherwise inaccessible to conventional drug delivery systems. Our method may thus be effective against intractable cancers”.