Effects of exercise training on antitumor efficacy of doxorubicin in MDA-MB-231 breast cancer xenografts.
OBJECTIVE
Exercise is becoming readily accepted as a beneficial adjunct therapy to maintain or enhance quality of life in breast cancer patients undergoing adjuvant chemotherapy. An essential precursor to these studies is to investigate whether exercise modulates the antitumor efficacy of chemotherapeutic agents.


METHODS
Athymic female mice were transplanted with MDA-MB-231 breast xenografts and randomly assigned to one of four groups (n = 21 per group): (a) control, (b) exercise-only, (c) doxorubicin-only, or (d) exercise + doxorubicin. Exercise groups performed progressive treadmill running up to 18 m/min at 0% grade for 45 minutes, 5 d/wk for 8 weeks.


RESULTS
Tumor growth delay was significantly longer in the doxorubicin-only and exercise + doxorubicin groups compared with the control (median 42 versus 25 days, P = 0.0082; 36 versus 25 days, P = 0.029, respectively) and exercise-only groups (median 42 versus 25 days, P = 0.029; 36 versus 25 days, P = 0.080, respectively). There was no significant difference between the doxorubicin-only and exercise + doxorubicin groups (median 42 versus 36 days, P = 0.33), suggesting that moderate intensity exercise does not significantly influence doxorubicin-induced tumor growth delay.


CONCLUSIONS
These studies are essential to fully understand the safety and application of exercise as a supportive intervention in cancer control.
Jones
Lee W
LW
Department of Medicine, Duke University Medical Center, Durham, NC 27705, USA. lee.w.jones@duke.edu
Eves
Neil D
ND
Courneya
Kerry S
KS
Chiu
Brian K
BK
Baracos
Vickie E
VE
Hanson
John
J
Johnson
Lorelei
L
Mackey
John R
JR
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000628:therapy*; D051379:Mice; D008819:Mice, Nude; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D016019:Survival Analysis; D013997:Time Factors; D023041:Xenograft Model Antitumor Assays / Q000379:methods
D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin