Transformation of blood monocytes to giant cells in vitro from patients with breast cancer

A call for standardization: Evaluating different methodologies to induce in vitro foreign body giant cell formation for biomaterials research and design

Foreign body giant cells (FBGCs) are crucial in the foreign body reaction at the biomaterial-tissue interface, forming through the fusion of cells from the monocyte/macrophage lineage and performing functions such as material degradation and fibrous encapsulation. Yet, their presence and role in biomaterials research is only slowly unveiled. This review analyzed existing FBGC literature identified through a search string and sources from FBGC articles to evaluate the most commonly used methods and highlight the challenges in establishing a standardized protocol. Our findings revealed a fragmented research landscape marked by significant variability in in vitro culture conditions, i.e., cell origin and type, culture media and sera, fusion-inducing factors, seeding density, culture surface, and inconsistencies in the read-outs. This complicates efforts toward standardization and hampers cross-study comparisons. Based on these results, we highlight the need and propose guidelines for standardized culture protocols for FBGC research. Overall, this review aims to underscore the relevance of improving reproducibility and reliability in FBGC research, facilitating effective cross-study comparisons and advancing understanding of FBGC formation and function, ultimately contributing to designing more effective biomaterial-based therapies. STATEMENT OF SIGNIFICANCE: Foreign body giant cells (FBGCs) are crucial in the body's response to implanted biomaterials. Yet, current research addressing their role and impact is highly fragmented. This review comprehensively and systematically examines the diverse methodologies and definitions used in FBGC research and identifies critical gaps and inconsistencies hindering the reproducibility and comparison of findings. By advocating for standardized protocols, we aim to enhance the reliability and equivalence of research, thus providing a stronger foundation for understanding biomaterial-driven FBGC formation and function. Establishing such a framework will impact biomaterial-based therapies, supporting their effectiveness and safety in medical applications, and is thus of relevance for scientists, companies, and clinicians in the biomaterial and medical device communities.

Bilateral Infiltrating Lobular Carcinoma of the Breast with Osteoclast-Like Giant Cells

A case of bilateral infiltrating lobular carcinoma of the breast containing osteoclast-like giant cells is presented. Notable pathologic features include prominent tumor-associated angiogenesis and the presence of osteoclast-like giant cells in axillary lymph node metastases. Immunohistologic and ultrastructural examination support a nonepithelial, histiocytic origin for the giant cells, and results are similar to previous reports of osteoclast-like giant cells associated with breast carcinoma. This is the first report of bilateral pure infiltrating lobular carcinoma of the breast with osteoclast-like giant cells and the first case of pure lobular carcinoma with osteoclast-like giant cells present in lymph node metastases.

Human tumour-associated macrophages are capable of bone resorption

Cellular mechanisms of bone resorption associated with skeletal metastasis are poorly understood. Human tumour-associated macrophages (TAMs) isolated from primary lung carcinomas were incubated on bone slices where they formed resorption lacunae after 14 days co-culture with a mouse marrow-derived stromal cell line (ST2) with added 1 alpha, 25-dihydroxy Vitamin D3 and dexamethasone. These co-cultures were associated with the formation of increased numbers of tartrate resistant acid phosphatase positive mononuclear and multinucleated cells. Similar cocultures of ST2 cells with normal alveolar macrophages did not result in lacunar resorption. Both in the presence and absence of ST2 cells, TAMs and normal alveolar macrophages produced roughening of the bone surface with exposure of mineralised collagen fibres. TAMs are capable of both low-grade surface resorption and high-grade lacunar resorption of bone, and a specific interaction with stromal cells is necessary for the latter to occur. TAMs may thus directly contribute to the bone resorption associated with skeletal metastasis.

An evaluation of the putative human mammary tumour retrovirus associated with peripheral blood monocytes

The primary aims of this study were purification and molecular cloning of a putative retrovirus designated human mammary tumour virus (HMTV). However, our preliminary unpublished data of negative reverse transcriptase (RT) activity in ostensibly 'infected' cells led us to re-examine the evidence for this virus; namely multinucleate giant cell (MNGC) formation and RT activity in cultured blood monocytes from breast cancer patients versus benign breast tumour and normal control subjects. MNGCs from by fusion of monocytes and we estimated the total number of cell fusions which had occurred after 10 days of culture in vitro by counting cells with two, three, four and five or more nuclei (n) and by measuring the density of adherent mononuclear cells for each subject studied. We found no clear-cut difference in MNGC formation between the three subject groups. Moreover, a substantial number of cultures, encompassing the three groups, showed far more MNGCs per 10(5) monocytes than previously reported. Various parametric and nonparametric statistical analyses were performed on the multinucleate cell data and only one parametric test, which utilised the density of monolayers as a co-variate, showed a statistically significant difference at the 5% level between the breast cancer and the normal subject groups. We observed marked subject-to-subject variation in multinucleate cell formation and we suggest that the evidence for a difference between the breast cancer and the normal groups is marginal. Further, MNGC formation by breast cancer monocytes may not be attributed to the presence of a retrovirus since 5'-Azacytidine (AZA), an agent known to stimulate replication of latent retroviruses showed no effect on the MNGC formation. In addition, culture supernatants from the three groups were assayed for RT activity and no test sample gave a significant signal above background. Preliminary transmission electron microscopy analysis failed to identify viral particles in MNGCs.

The origin and nature of stromal osteoclast-like multinucleated giant cells in breast carcinoma: implications for tumour osteolysis and macrophage biology

The origin and nature of osteoclast-like multinucleated giant cells (OMGCs), in extraskeletal neoplasms, is uncertain. The ultrastructure, antigenic phenotype and function of OMGCsm in a breast carcinoma were studied in order to clarify the relationship between OMGCs, osteoclasts and other cells of the mononuclear phagocyte system (MPS). OMGCs resorbed cortical bone in a manner similar to osteoclasts. However, unlike osteoclasts, OMGCs did not possess a ruffled border or clear zone, and expressed HLA-DR and Fc receptors and CD14, CD16, CD18 and CD11 (p150,95) antigens. In addition, OMGCs failed to respond morphologically to calcitonin and were directly stimulated by parathyroid hormone (PTH) to increase bone resorption. These findings suggest that OMGCs are a specific type of macrophage polykaryon distinct from both osteoclasts and other types of inflammatory polykaryon. Occasional smaller (20-25 microns) macrophage-like cells were also associated with resorption pits. Bone resorption by OMGCs isolated from the breast indicates that a cell of the MPS can be transplanted to a new tissue location and perform a highly specialised function appropriate to an MPS cell of that tissue (i.e. the osteoclast). PTH stimulation of bone resorption by OMGCs suggests that PTH or a PTH-like protein, may be involved in the bone resorption and consequent hypercalcaemia associated with metastatic breast cancer.

The effect of tamoxifen and medroxyprogesterone on giant cell formation by monocytes from patients with breast cancer

Incubation of peripheral blood monocytes from patients with breast cancer under agarose for 6 days at 37 degrees C in a 5% CO2 atmosphere resulted in giant cell formation. This phenomenon appeared to be mediated by retroviruses present in these cells. In this study giant cell formation was investigated in patients with primary stage I and II breast cancer before and 3 months after mastectomy with axillary lymph node clearance. Mastectomy had no significant inhibitory effect on giant cell formation. In vitro incubation of monocytes from patients with breast cancer in the presence of tamoxifen (Nolvadex) resulted in significant inhibition of giant cell formation (P less than 0.000003; paired Student's t-test). In vitro addition of medroxyprogesterone (Farlutal) to monocytes from patients with breast cancer also resulted in significant inhibition of giant cell formation (P less than 0.003: paired Student's t-test). Furthermore, incubation of monocytes from patients treated by mastectomy followed by 3 months treatment with adjuvant tamoxifen, resulted in a significant reduction (P less than 0.00007; paired Student's t-test) in the number of giant cells compared to the same samples tested before the commencement of the treatment. Giant cell formation may be used as a simple test to predicte the response of patients with breast cancer to either tamoxifen or medroxyprogesterone.

Particles with properties of retroviruses in monocytes from patients with breast cancer

An agent with the properties of a retrovirus has been detected regularly in monocytes from patients with breast cancer. In 97% of breast cancer patients the cell-free culture medium (CFCM) in which the monocytes had been cultured possessed reverse transcriptase (RT) activity. In contrast, RT activity was detected in the CFCM from only 11% of age and sex matched controls (p less than 0.0001; Wilcoxon rank sum test). The RT activity was associated with particles having a buoyant density of between 1.165 and 1.18 g/ml, similar to that of retroviruses. Treatment of the samples with non-ionic detergent abolished the peaking of the activity in this fraction. Enveloped particles (100-120 nm in diameter) with a fringed surface resembling murine mammary tumour virus were found on negative-stain electron microscopy in CFCM obtained from patients with breast cancer. Retrovirus-like particles were also observed in the cytoplasm of giant cells formed by monocytes from these patients, and also in macrophages in breast cancer tissue; however, no such particles were detected in the tumour cells. These findings strongly suggest the presence of a retrovirus in the monocytes from patients with breast cancer. The importance of these observations in the pathophysiology of carcinoma of the breast remains to be established.