Low calcium diet increases 4T1 mammary tumor carcinoma cell burden and bone pathology in mice

• Published in: PloS one Vol. 12; no. 7; p. e0180886
• Main Authors: Wang, Wendan, Gordon, Jody L., Philbrick, Kenneth A., Yang, Xujuan, Branscum, Adam J., Löhr, Christiane V., Haschek, Wanda M., Turner, Russell T., Iwaniec, Urszula T., Helferich, William G.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.07.2017; Public Library of Science (PLoS)
• Subjects: Animals; Biocompatibility; Biology; Biology and Life Sciences; Bioluminescence; Biomedical materials; Bone (cortical); Bone cancer; Bone growth; Bone Remodeling - drug effects; Bone turnover; Breast cancer; Calcium; Calcium (dietary); Calcium (Nutrient); Calcium, Dietary - pharmacology; Cancellous Bone - diagnostic imaging; Cancellous Bone - drug effects; Cancellous Bone - pathology; Cancer metastasis; Carcinoma; Cell Line, Tumor; Computed tomography; Cortical bone; Development and progression; Diet; Disease Progression; Female; Food science; Gordon, Kenneth; Health care; Histology; Infiltration; Inoculation; Kinases; Laboratory animals; Lesions; Lung cancer; Lungs; Mammary gland; Mammary Neoplasms, Animal - pathology; Medicine and Health Sciences; Metastases; Metastasis; Mice; Mice, Inbred BALB C; Muscles; Neoplasm Metastasis; Nutrient deficiency; Nutrition research; Osteogenesis; Osteolysis; Physiological aspects; Public health; Quality of life; Research and Analysis Methods; Tibia; Tibia - diagnostic imaging; Tibia - drug effects; Tibia - pathology; Tumor Burden - drug effects; Tumor cells; Tumors; Veterinary colleges; Veterinary medicine; X-Ray Microtomography; United States; Oregon; United States > US; Illinois
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0180886

Breast cancer metastasizes to bone in the majority of patients with advanced disease. We investigated the effects of inadequate dietary calcium (Ca) on bone turnover, tumor growth, and bone response to tumor in tibia inoculated with 4T1 mammary carcinoma cells. Nine-month-old female Balb/c mice were placed on an adequate Ca (5 g/kg diet, n = 30) or low Ca (80 mg/kg diet, n = 31) diet for 14 days, then injected intratibially with 1,000 4T1 cells (transfected with luciferase for bioluminescence imaging), and sacrificed at 5, 10, or 21 days post-inoculation (n = 7-10 mice/group). Control mice (n = 6/group) were injected with carrier and sacrificed at 10 days post-inoculation. Tibiae with muscle intact were excised and evaluated by microcomputed tomography and histology. In vivo bioluminescent imaging revealed that 4T1 cells metastasized to lung. Therefore, lungs were removed for quantification of tumor. Mice fed low Ca exhibited higher bone turnover and higher tibial lesion scores than mice fed adequate Ca. Lesion severity, manifested as cortical osteolysis and periosteal woven bone formation, and tumor cell infiltration to muscle, increased with time, irrespective of diet. However, for most skeletal endpoints the rates of increase were greater in mice consuming low Ca compared to mice consuming adequate Ca. Infiltration of tumor cells into adjacent muscle, but not metastasis to lung, was also greater in mice consuming low Ca diet. The findings suggest that high bone turnover due to Ca insufficiency results in greater local mammary tumor cell growth, cortical osteolysis, woven bone formation, and invasion to muscle in mice.