Intraosseous injection of RM1 murine prostate cancer cells promotes rapid osteolysis and periosteal bone deposition

Abstract

The molecular mechanisms associated with prostate cancer (PCa) progression within bone remain a topic of intense investigation. With the availability of transgenic mouse strains, a model of PCa for use in immune competent/transgenic mice would be highly beneficial. This study was designed to explore the utility of RM1 mouse PCa cells in investigations of tumor:bone interactions. The efficacies of several implantation techniques were examined for reliably producing intra-bone RM1 tumor growth and bone lesion formation in immune competent mice. Longitudinal monitoring of bone remodeling and lesion phenotypes was conducted by microcomputed tomography (μCT) and histological analyses. Our results indicate that direct intrabone injections of RM1 cells are necessary for tumor growth within bone and direct implantation promotes the rapid development of osteolytic bone lesions with periosteal bone deposition post-cortical breach. In vitro, RM1 cells promote the proliferation of osteoblast (MC3T3-E1) and osteoclast (Raw264.7) progenitors in a dose dependent manner. Conditioned culture media from RM1 cells appears to promote earlier expression of genes/ proteins associated with osteoblastic differentiation. While clearly stimulating osteoclast function in vivo, RM1 cells had little effect on differentiation and tartate resistant acid phosphatase (TRAP) expression by Raw264.7 cells. These data, coupled with in vivo μCT images, indicate the ability of RM1 cells to induce mixed, yet predominentally osteolytic, responses in bone and illustrate the potential of RM1 cells as a model of investigating prostate tumor:stroma interactions in immune competent/transgenic mice on a C57BL/6 background.

Apoptosis-induced CXCL5 accelerates inflammation and growth of prostate tumor metastases in bone

“…Figure 1C indicates that these cytokines were transcriptionally upregulated in macrophages interacting with apoptotic cancer cells in contrast with noncancer cells, which correlates with the cytokine array results. Since prosmodel for investigations of prostate cancer interactions with bone marrow stroma as they promote osteolytic lesions accompanied by periosteal bone deposition in immunocompetent C57BL/6J mice (9,15). Human PC3 cancer cells, originally isolated from prostate cancer bone metastasis (16), have been used extensively for their ability to metastasize to the bone when injected in immunocompromised mice via intracardiac inoculation (17).…”

Interleukin-27 Gene Delivery for Modifying Malignant Interactions Between Prostate Tumor and Bone

“…TRAMP-C2 cells were transduced with a lentivirus expressing activated H-ras G12V (Lv-Hras) at a multiplicity of infection of 1 and a lentivirus expressing mouse androgen receptor at a multiplicity of infection of 1, resulting in TC2R. The RM1 murine prostate cancer cell line (McCabe et al, 2008) has the ability to aggressively grow in the bone microenvironment upon intratibial implantation. Prostate cancer cells were cultured in DMEM:F12 (Cellgro) with 10% FBS (GeneMate) and 1% PS (Invitrogen), and regularly passaged by trypsinization (0.05% [v/v] trypsin, 0.53 mM EDTA; Cellgro).…”

“…The cell line we have developed (TC2R) can form bone lesions representative of the human disease, including osteoblastic and osteolytic reactions in vivo after intratibial implantation into syngeneic C57/BL6 mice. TC2R allows us to explore the full effects of immune therapies for skeletal metastasis of prostate cancer and might be better suited for testing immunotherapy efficacy compared with other available immunecompetent models (RM1, RM1.BM), which are predominantly osteolytic (McCabe et al, 2008;Hung et al, 2011). Also, TC2R may be useful for testing prostate cancer therapies targeting the androgen receptor via drugs or transcriptional-targeted gene therapy (Figueiredo et al, 2007).…”

MicroCT: An Essential Tool in Bone Metastasis Research

“…Metastatic tumors in mice are largely osteolytic or a combination of osteoblastic and osteolytic (Singh & Figg, 2005). Using microCT, intratibial injections of prostate cancer cells was shown to result in extensive osteolysis of the trabeculae, followed by periosteal bone deposition (McCabe et al, 2008). By scanning the same region of bone over time, the rate of osteolysis can be measured and used to approximate the kinetics of tumor growth.…”

“…Although alterations in bone remodelling in patients with distant, primary cancers have been described, the mechanisms behind this pre-metastatic bone turnover have not been elucidated. Having previously established that intratibial injection of prostate cancer cells stimulates osteolysis (McCabe et al, 2008;McCabe et al, 2011), we wanted to determine the effects of primary tumor growth on the bone microenvironment. We used subcutaneous injections of prostate cancer cells to simulate a primary tumor and performed microCT scanning to assess changes in the bone structure.…”