A new DNA vaccine inhibited malignant melanoma, a deadly form of skin cancer, in mice by eliciting antibodies that target a gastrin-releasing peptide which is known to play a key role in cancer development. The researchers from China and the U.S. report their findings in the July 2009 issue of the journal Clinical and Vaccine Immunology.
Gastrin-releasing peptide (GRP) is an important human peptide that regulates gastric acid secretion and motor function as well as elicits gastrin release. Previous research has shown that GRP plays a significant role in human cancers through atypical expression of the GRP receptor and GRP binding that activates cellular signaling and results in increased cell production and tumor formation. Anti-GRP antibodies have displayed promising antitumoral activity and DNA vaccines targeting GRP are a hopeful therapeutic approach.
In the study researchers developed a novel anti-GRP DNA vaccine including various immunoadjuvants (substances to improve the immune response) and monitored anti-GRP antibody levels in vaccinated mice. Intramuscular injections induced high levels of specific antibodies against GRP as well as suppressed the growth of melanoma cells. Additionally, researchers intravenously injected cells in the lungs and found that cells were highly diminished indicating that the vaccine may also inhibit cancer from spreading.
"In conclusion, we have demonstrated for the first time that immune responses which are elicited by a novel anti-GRP DNA vaccine suppress the proliferation and growth of melanoma tumors in mice," say the researchers. "The antiangiogenesis and antimetastastic activities of this DNA vaccine suggest a novel approach against various cancers, especially malignant melanoma."
(J. Fang, Y. Lu, K. Ouyang, G. Wu, H. Zhang, Y. Liu, Y. Chen, M. Lin, H. Wang, L. Jin, R. Cao, R.S. Roque, L. Zong, J. Liu, T. Li. 2009. Specific antibodies elicited by a novel DNA vaccine targeting gastrin-releasing peptide inhibit murine melanoma growth in vitro. Clinical and Vaccine Immunology, 16. 7: 1033-1039.)