title: Chronic mild stress facilitates melanoma tumor growth in mouse lines selected for high and low stress-induced analgesia.
abstract: Both chronic stress conditions and hyperergic reaction to environmental stress are known to enhance cancer susceptibility. We described two mouse lines that displayed high (HA) and low (LA) swim stress-induced analgesia (SSIA) to investigate the relationship between inherited differences in sensitivity to stress and proneness to an increased growth rate of subcutaneously inoculated melanoma. These lines display several genetic and physiological differences, among which distinct sensitivity to mutagens and susceptibility to cancer are especially noticeable. High analgesic mice display high proneness both to stress and a rapid local spread of B16F0 melanoma. However, stress-resistant LA mice do not develop melanoma tumors after inoculation, or if so, tumors regress spontaneously. We found that the chronic mild stress (CMS) procedure leads to enhanced interlinear differences in melanoma susceptibility. Tumors developed faster in stress conditions in both lines. However, LA mice still displayed a tendency for spontaneous regression, and 50% of LA mice did not develop a tumor, even under stressed conditions. Moreover, we showed that chronic stress, but not tumor progression, induces depressive behavior, which may be an important clue in cancer therapy. Our results clearly indicate how the interaction between genetic susceptibility to stress and environmental stress determine the risk and progression of melanoma. To our knowledge, HA/LA mouse lines are the first animal models of distinct melanoma progression mediated by inherited differences in stress reactivity.
authors.affiliation: Department of Molecular Cytogenetics, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Postepu 1 Str., 05-552 Magdalenka, Poland.
authors.forename: Agnieszka R
authors.initials: AR
authors.lastname: Ragan
authors.forename: Anna
authors.initials: A
authors.lastname: Lesniak
authors.forename: Marta
authors.initials: M
authors.lastname: Bochynska-Czyz
authors.forename: Anna
authors.initials: A
authors.lastname: Kosson
authors.forename: Hanna
authors.initials: H
authors.lastname: Szymanska
authors.forename: Kazimiera
authors.initials: K
authors.lastname: Pysniak
authors.forename: Marta
authors.initials: M
authors.lastname: Gajewska
authors.forename: Andrzej W
authors.initials: AW
authors.lastname: Lipkowski
authors.forename: Mariusz
authors.initials: M
authors.lastname: Sacharczuk
mesh_terms: D000698:Analgesia; D000818:Animals; D001835:Body Weight; D003863:Depression / Q000209:etiology; D018450:Disease Progression; D004435:Eating; D020022:Genetic Predisposition to Disease; D019417:Hindlimb Suspension; D006930:Hyperalgesia / Q000503:physiopathology*; D008297:Male; D008546:Melanoma, Experimental / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008892:Milk; D009368:Neoplasm Transplantation; D059225:Nociception / Q000502:physiology; D010146:Pain / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics*; D013550:Swimming