New York: A virus can be used to kill triple-negative breast cancer cells and tumours grown from these cells in mice, finds a new research.

Understanding how the virus kills cancer cells may lead to new treatments for breast cancer, according to Penn State College of Medicine researchers.

Adeno-associated virus type 2 (AAV2) infects humans, but is not known to cause sickness.

'Treatment of breast cancer remains difficult because there are multiple signalling pathways that promote tumour growth and develop resistance to treatment,' said Craig Meyers, professor of microbiology and immunology at Pennsylvania State University in the US.

In prior studies, the researchers tested the virus on a variety of breast cancers that represent degrees of aggressiveness on human papillomavirus-positive cervical cancer cells.

The virus initiated apoptosis - natural cell death - in cancer cells without affecting healthy cells.

Treatment of breast cancer differs from patient to patient due to differences in tumours.

A triple-negative breast cancer is typically aggressive.

'There is an urgent and ongoing need for the development of novel therapies which efficiently target triple-negative breast cancers,' Meyers said.

In the current study, the researchers tested AAV2 on a cell-line representative of triple-negative breast cancer.

The AAV2 killed 100 percent of the cells in the laboratory by activating proteins called caspases, which are essential for the cell's natural death.

AAV2 mediated cell killing of multiple breast cancer cell lines representing both low and high grades of cancer and targeted the cancer cells independent of hormone or growth factor classification.

'These results are significant, since tumour death in response to therapy is also used as the measure of an effective chemotherapeutic,' Meyers said.

The findings appeared in the journal Cancer Biology & Therapy.