Engineered oncolytic herpes virus inhibits ovarian and breast cancer metastases

Past decades have witnessed significant progress in the ability to treat numerous cancers by means of surgery, chemo- and radio-therapy, or combinations thereof. However, many treatments prolong life for a short time only, or are associated with a poor quality of life.

Lead investigator Gabriella Campadelli-Fiume and colleagues re-engineered the entry apparatus of a candidate oncolytic herpesvirus. The reprogrammed virus no longer infects the cells usually targeted by the wild-type virus, nor does it cause herpes-related pathologies. Rather, it acts as a specific weapon against tumor cells that express the HER-2 oncogene.

"Numerous laboratories worldwide are using viruses as more specific weapons against cancer cells, called oncolytic viruses," says Campadelli-Fiume, Professor of Microbiology and Virology. "Safety concerns prevailed so far, and all oncolytic herpesviruses now in clinical trials are debilitated viruses, effective only against a fraction of tumors. We were the first to obtain a herpes virus reprogrammed to enter HER-2-positive tumor cells, unable to infect any other cell, yet preserves the full-blown killing capacity of the wild-type HSV."

Additionally, the laboratory of Pier-Luigi Lollini, Patrizia Nanni and Carla De Giovanni in collaboration with researchers at the Rizzoli Institute, established the new model of human cancer metastases in mice that was used to demonstrate the therapeutic efficacy of the reprogrammed virus.

The positive results obtained in the treatment of experimental metastasis hold the promise that the newly retargeted oncolytic HSV described in PLOS Pathogens is a good candidate to become a novel type of cancer treatment, and represents a key step forward in the path to clinical trials for late stage human breast and ovarian cancers.