ScienceDaily (Mar. 24, 2009) — Infection with human cytomegalovirus (HCMV) triggers expression of the telomerase reverse transcriptase (hTERT) gene in both normal human cells and tumor cells grown in culture.

HCMV has been suspected of causing or promoting cancer, but the mechanism by which the virus acts has been unclear. Several other cancer-related viruses stimulate telomerase activity, which promotes cell proliferation and immortalization.

To learn whether HCMV induces telomerase activity, Dawei Xu, M.D., Ph.D., of the Karolinska Institute in Stockholm, Sweden, and colleagues infected normal diploid fibroblasts and malignant glioma cells with HCMV or introduced a copy of the viral immediate early antigen 72 (IE-72) gene into the cells.

Infection with HCMV induced telomerase expression in both normal and malignant human cells. Introduction of the viral IE-72 gene also induced telomerase activity in both cell types.

"In this study, we reveal a novel mechanism through which HCMV may be linked to or modulate oncogenesis by demonstrating that HCMV stimulates hTERT transcription, thereby activating telomerase, which is essential for the immortalization and transformation of human cells," the authors write.

In an accompanying editorial, Jindrich Cinatl Jr., Ph.D., of the Universität Frankfurt in Germany and colleagues note that they hypothesized previously that HCMV may increase tumor malignancy rather than instigate malignancy. The results by Xu and colleagues may provide important mechanistic insight as to how such a modulatory role could occur.

"…HCMV-induced telomerase activation represents a mechanism that is of possible relevance for both (initiation of) malignant trans¬formation and oncomodulation by HCMV infection," the editorialists write.

The research is published in the March 24 online issue of the Journal of the National Cancer Institute.

Story Source:

Adapted from materials provided by Journal of the National Cancer Institute, via EurekAlert!, a service of AAAS.

Journal Reference:

1. Klas Strååt, Cheng Liu, Afsar Rahbar, Qingjun Zhu, Li Liu, Nina Wolmer-Solberg, Fenglan Lou, Zhaoxu Liu, Jie Shen, Jihui Jia, Satoru Kyo, Magnus Björkholm, Jan Sjöberg, Cecilia Söderberg-Nauclér, and Dawei Xu. Activation of Telomerase by Human Cytomegalovirus. Journal of the National Cancer Institute, 2009; DOI: 0.1093/jnci/djp031

Related Stories

Tissue Engineering Technique Does Not Cause Tumor Growth (Mar. 7, 2006) — A gene therapy approach used in creating new arteries for older patients does not appear to cause cancer, according to a pilot study by Yale School of Medicine researchers reported in the Proceedings ...  > read more

Researchers Find Way To Make Tumor Cells Easier To Destroy (May 7, 2008) — Radiation oncology researchers found that tumors have a built-in mechanism that protects them from heat damage and most likely decreases the benefit of hyperthermia and radiation as a combined ...  > read more

Mechanism That Explains How Cancer Enzyme Winds Up On Ends Of Chromosomes Found (July 13, 2008) — Researchers have shown a mechanism that explains how two essential components of human telomerase -- normally active only in early prenatal development but turned back on during cancer growth -- are ...  > read more

New Target For Cancer Therapy Identified (Sep. 21, 2006) — A new target for cancer therapy has been identified by Monash University scientists investigating the cell signalling pathways that turn on a gene involved in cancer ...  > read more

Search ScienceDaily

Unraveling Brain Tumors