In the October 2013 issue of Biochemical and Biophysical Research Communications, Ni Hou and colleagues from the Xi’an Jiaotong University School of Medicine, Xi’an, Shaanxi, China, demonstrated that a novel form of sound stress induced a T helper (Th)2 shift and that this is related to colon cancer progression in mice.
Numerous epidemiological reports indicate a connection between stress and cancer.
T helper (Th)1 immunity is considered a major defense mechanism in immunosurveillance related to tumor development. A profound Th2 shift linked to a deficiency of IL-12, and overproduction of IL-10 and TGF-β seems to play an inappropriate immunosuppressive role, allowing increased tumor growth (Chouaib, S et al., Immunol. Today, 1997, 18:493).
Animal models have been often used to study these interactions.
In fact, two reports in Science magazine, using mice subjected to inescapable shock were perhaps the first to document a link between experimental stress and tumor growth (Sklar LS & Anisman H, Science, 1979, 205:513; Visintainer MA et al., Science. 1982, 216:437).
In the Biochemical and Biophysical Research Communications study, Ni Hou et al. report that mice exposed to a chronic scream sound stress (frequencies from 0.5 kHz to 4 kHz; 6 h daily for 2 weeks), when compared to control animals, had enlarged adrenal cortex zona fasciculata, and increased serum concentrations of norepinephrine (noradrenaline) and corticosterone.
These mice also had lower microarray intensities of serum TNF-α and IL-2 (Th1 cytokines), higher intensities of serum IL-4, IL-5, IL-6, IL-10, and IL-13 (Th2 cytokines), and decreased IFN-γ/IL-4 ratio in tumor infiltrated lymphocytes and tumor microenvironment.
All these neurohormonal-immune changes were associated with morphological alterations indicating colon cancer progression.
These results may suggest that further studies investigating the impact of chronic stress on colon cancer progression are warranted.