A new study has found that the malignancy of lung cancer is determined by micro-RNA.
Professor Dr. Heike Allgayer, head of a Clinical Cooperation Unit of DKFZ and UMM, is an expert for those cellular processes that lead to metastasis in cancer.
In recent years, scientists have discovered that production of many proteins is regulated by what are called micro-RNAs.
These RNA molecules, which consist of only about 23 building blocks, attach specifically to messenger RNAs, which contain the blueprints for proteins. In this way, they block the production of the respective protein.
"We believe that micro-RNAs also play an important role in metastasis and that they program cells in a way that leads to malignant growth," explained Heike Allgayer medical researcher.
In an international collaboration with researchers in Turin, Italy, Allgayer and her team used various cell lines of non-small cell lung cancer to investigate a particularly suspicious candidate called miR-200c and its role in malignant growth.
The research team found out that the less miR-200c is produced by a cell line, the higher its motility and its capacity to invade surrounding tissue.
When the researchers experimentally equipped the cancer cells with additional miR-200c, the amount of tissue-anchoring molecules on their surface increased and their invasive capacity became lower.
In animal experiments, these cells produced less metastasis.
A dreaded characteristic of non-small cell lung cancer is its resistance to chemotherapy and targeted anticancer drugs.
A lack of miR-200c also play a role here-therapy-resistant lung cancer cell lines that were experimentally equipped with miR-200c could subsequently be killed by the chemotherapy drug cisplatin and responded to cetuximab, a drug that block growth signals.
The researchers also discovered how the loss of miR-200c is brought about in cancer cells.
The researchers found that the lower the miR-200c level in the cancer cells, the more frequently metastasis had already begun.
"Our results clearly show a connection between a loss of miR-200c and transition to aggressive, invasive growth, metastasis and chemoresistance," summarized Heike Allgayer.