title: Distribution of macrophages, osteoclasts and the B-lymphocyte lineage in osteolytic metastasis of mouse mammary carcinoma.
abstract: The purpose of this study was to examine the localization of macrophages, B-lymphocytes and osteoclasts in tumoral lesions of mammary carcinoma metastasized to bone of non-immunocompromised mice. Mouse mammary carcinoma cells (BALB/c-MC) were injected through the left cardiac ventricle into 5-week-old female wild-type Balb/c mice. The femora and tibiae of mice with metastasized cancer were extracted, and thereafter processed for histochemical analyses. The foci of metastasized tumor cells occupied the metaphyseal area, and the cell death zones could be identified within the tumor mass. Abundant tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were found among the alkaline phosphatase (ALP)-reactive osteoblastic cell layer that covered the bone surface neighboring the metastatic lesion. In contrast, F4/80-positive macrophages/monocytes were localized adjacent to, or invading the metastatic tissue. In addition, some F4/80-positive cells were found in the aforementioned cell death zones. Unlike F4/80-positive cells, CD45R-positive B-lymphocytes did not accumulate at the surfaces of the tumor lesions, nor infiltrate into them, but were found scattered over bone marrow. Interestingly, some CD45R-positive cells were observed close to TRAP-positive osteoclasts in the stromal tissue surrounding the tumor lesion. Our findings suggest that, in the bone metastatic lesions of non-immunocompromised mice, F4/80-positive macrophages/monocytes accumulated on and/or infiltrated into the tumor nests, while CD45R-positive B-lymphocytes were associated with osteoclasts, rather than attacking metastatic tumor cells.
authors.affiliation: Center for Transdisciplinary Research, Niigata University, Niigata, Japan. liminqi@dent.niigata-u.ac.jp
authors.forename: Minqi
authors.initials: M
authors.lastname: Li
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Ono
authors.forename: Paulo Henrique Luiz
authors.initials: PH
authors.lastname: de Freitas
authors.forename: Ubaidus
authors.initials: U
authors.lastname: Sobhan
authors.forename: Taku
authors.initials: T
authors.lastname: Kojima
authors.forename: Junko
authors.initials: J
authors.lastname: Shimomura
authors.forename: Kimimitsu
authors.initials: K
authors.lastname: Oda
authors.forename: Norio
authors.initials: N
authors.lastname: Amizuka
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000473:pathology* / Q000648:ultrastructure; D001859:Bone Neoplasms / Q000473:pathology / Q000556:secondary* / Q000648:ultrastructure; D002277:Carcinoma / Q000276:immunology* / Q000473:pathology* / Q000648:ultrastructure; D019070:Cell Lineage / Q000276:immunology; D005260:Female; D008264:Macrophages / Q000473:pathology* / Q000648:ultrastructure; D008325:Mammary Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology* / Q000648:ultrastructure; D051379:Mice; D008807:Mice, Inbred BALB C; D046529:Microscopy, Electron, Transmission; D010010:Osteoclasts / Q000473:pathology* / Q000648:ultrastructure