Rosetta Genomics has reported in-vivo efficacy data for a systemic microRNA-based cancer therapeutic for human hepato-cellular carcinoma (HCC or liver cancer).

Rosetta’s scientists first identified miR-191, a microRNA that is abnormally over-expressed in human liver cancer cells. When microRNA is inhibited effectively, cell proliferation is reduced and and cell-death of liver tumor cells is promoted.

The scientists then used an in-vivo model called Orthotopic Xenograft, in which an artificial tumor fragment derived from a human liver cancer cell line is transplanted into livers of mice, in order to evaluate the efficacy of systemic microRNA-based treatment in these mice.

Chemically modified antisense oligos (ASOs) were delivered systemically, targeting the over-expressed microRNA. Using this animal model, the scientists have shown that the targeted microRNA was markedly decreased in mice livers and was practically undetectable within the tumor itself, and that the tumor mass was significantly reduced two-fold, within 40 days of treatment.

“We view this study as a landmark event in the development of microRNA based cancer therapeutics,” said Amir Avniel, President and CEO of Rosetta Genomics.

Liver cancer is the third cause of cancer death globally, affecting more than 19,000 patients annually in the US alone. Prognosis is extremely grim, with nine out of 10 patients dying within five years.

Sorafenib (Nexavar), the only oral anti-cancer drug currently approved for systemic therapy for HCC, extends survival by approximately three months. Interestingly, the researchers showed that Dioxin, one of the most toxic substance ever identified and a known liver cancer carcinogen, markedly increases the expression of the targeted microRNA.

The data was presented last week in Canada at the Keystone Symposium for Therapeutic Modulation of RNA Using Oligonucleotides.