Researchers at Yale University and Asuragen, Inc say that a small RNA molecule, known as let-7 microRNA (miRNA) may play a direct role in stopping cancer progression after finding that it can considerably reduce cancer growth in multiple mouse models of lung cancer.
Lung cancer is the most common and deadly form of cancer worldwide. This study led by Frank Slack, associate professor of molecular, cellular and developmental biology at Yale, introduces a new theory of using miRNAs as effective therapeutic agents to treat human cancer.
"We believe this is the first report of a miRNA being used to a beneficial effect on any cancer, let alone lung cancers, the deadliest of all cancers worldwide," said Slack.
Firstly, the researchers located the let-7 miRNA in C. elegans, a tiny worm used as a model system for studying how organisms develop, grow and age. Later they demonstrated that in humans, let-7 negatively regulates a well-known determinant of human lung cancers, the RAS oncogene.
The Slack lab in collaboration with scientists at Asuragen, studied the tumour suppressor activity of this small RNA and found that let-7 is usually present at substantially reduced levels in lung tumours, and that these reduced levels likely contribute to tumour development.
The researches also demonstrated that let-7 can be used as an intranasal drug for reducing tumour formation in a RAS mouse model lung cancer.
"We believe that our studies provide the first direct evidence in mammals, that let-7 functions as a tumour suppressor gene. Because multiple cell lines and mouse models of lung cancer were used, it appears that therapeutic application of let-7 may provide benefits to a broad group of lung cancer patients," said Slack.
He added: "This has been a very productive industry-academic collaboration between Yale and Asuragen scientists" commented Matt Winkler CEO of Asuragen. This work provides further evidence of the importance of miRNAs in the development of cancer and provides additional support for miRNA replacement therapy as an important component of effective cancer treatment regimens of the future."
The study is published in the journal Cell Cycle.