Osteoclast-mediated osteolysis in bone metastasis from renal cell carcinoma

Cancer Metastases to the Hand: A Systematic Review and Meta-analysis

BACKGROUND

Metastatic lesions to the hand or wrist are rare and can mimic inflammatory and benign processes such as gout and infections. This often leads to misdiagnosis, underreporting, and delays in treatment. The purpose of this study was to examine all known cases of metastasis to the hand or wrist available in the literature and to analyze demographic trends, metastasis characteristics, and clinical course, and provide recommendations for management.

METHODS

An online systematic review of MEDLINE, Embase, PubMed, and the Cochrane Library from inception to January 7, 2022, was completed. Studies outlining the care of a patient with acrometastases of the hand were included. Data extracted included age, sex, site of primary tumor and metastasis, presence of other metastases, time from primary diagnosis to acrometastasis diagnosis, misdiagnosis, treatment, and survival.

RESULTS

Between 1889 and present, 871 lesions were described in 676 patients who met the inclusion criteria. There was no predilection for hand dominance or site of previous trauma. The mean age among patients was 59.5 (1.5-91) years, and male sex was more common (64.6%). The most common primary cancer source was the lung (39.2%), followed by the kidney (10.8%). The distal phalanx was the most frequently cited tumor location (33.7%). Mean survival after diagnosis of acrometastasis was 6.3 months (0.25-50) ± 11.5 months.

CONCLUSION

Acrometastasis remains an uncommon presentation of metastatic disease with poor prognosis. Treatment currently focuses on pain management and optimizing functional outcomes. Our review led to the development of 7 treatment recommendations when managing these patients.

An interdisciplinary consensus on the management of bone metastases from renal cell carcinoma

Bone is a major site of haematogenous tumour cell spread in renal cell carcinoma (RCC), and most patients with RCC will develop painful and functionally disabling bone metastases at advanced disease stages. The prognosis of these patients is generally poor and the treatment is, therefore, aimed at palliation. However, RCC-associated bone metastases can be curable in select patients. Current data support a multimodal management strategy that includes wide resection of lesions, radiotherapy, systemic therapy, and other local treatment options, which can improve quality of life and survival. Nevertheless, the optimal approach for metastatic bone disease in RCC has not yet been defined and practical recommendations are rare. To improve the management and outcomes of patients with RCC and bone metastases, the International Kidney Cancer Coalition and the interdisciplinary working group on renal tumours of the German Cancer Society convened a meeting of experts with a global perspective to perform an unstructured review and elaborate on current treatment strategies on the basis of published data and expertise. The panel formulated recommendations for the diagnosis and treatment of patients with RCC and metastasis to the bone. Furthermore, the experts summarized current challenges and unmet patient needs that should be addressed in the future.

In this Expert Consensus, Grünwald et al. summarize their recommendations for the diagnosis and treatment of patients with renal cell carcinoma and metastasis to the bone. They also outline current challenges and unmet patient needs that should be addressed in the future.

Bone-specific poly(ethylene sodium phosphate)-bearing biodegradable nanoparticles

Chemotherapy is the most reliable treatment for osteoporosis and osseous metastases. To facilitate better drug delivery for bone treatments, a novel preparation of polymeric nanoparticles with high affinity to bone has been prepared. Two-step synthesis of cholesteryl-functionalized poly(ethylene sodium phosphate) (Ch-PEP_n·Na) was performed via ring-opening polymerization of cyclic phosphoesters and the demethylation. The molecular weight of Ch-PEP_n·Na could be well controlled by changing the ratio of cholesterol and cyclic phosphoesters. Because Ch-PEP_n·Na exhibits an amphiphilic nature in aqueous media, Ch-PEP_n·Na-bearing nanoparticles (PEP_n·Na NPs) were prepared by a solvent evaporation technique. The size of the nanoparticles investigated in the current study is approximately 100nm, which was determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Due to the presence of highly water-soluble polymer chains, dispersion of PEP_n·Na NPs in aqueous media was stable for at least 1 week. Hemolytic activity of PEP_n·Na NPs was found to be low and PEP_n·Na NPs did not disintegrate mammalian cell membranes. Additionally, cytotoxicity of PEP_n·Na NPs was not observed at concentrations below 100μg/mL. The adsorption of PEP_n·Na NPs on hydroxyapatite (HAp) microparticles was studied in comparison with poly(ethylene glycol) nanoparticles (PEG NPs). Both PEP_n·Na NPs and PEG NPs adsorbed well onto HAp microparticles in distilled water with binding equilibrium constants (K_HAp) for PEP_n·Na NPs and PEG NPs of 3.6×10⁶ and 7.9×10⁶, respectively. In contrast, only PEP_n·Na NPs adsorbed onto HAp microparticles in a saline phosphate buffer. Moreover, the adsorption of PEP_n·Na NPs onto HAp microparticles occurred even in the presence of 1.2mM calcium ions or low-pH media. The affinity of the nanoparticles to bovine bone slices was also studied, with the result that large quantities of adsorbed PEP_n·Na NPs were observed on the slices by scanning electron microscope.

Combination with third-generation bisphosphonate (YM529) and interferon-alpha can inhibit the progression of established bone renal cell carcinoma

The aim of this study was to investigate whether the third-generation nitrogen-containing bisphosphonate (YM529) can inhibit the progression of established bone renal cell carcinoma (RCC) and to elucidate its mechanism. Antiproliferative effect and apoptosis induction of RCC cells and mouse osteoclasts by YM529 and/or interferon-alpha (IFN-α) were evaluated in vitro using cell counting and in vivo using soft X-ray, the TUNEL method and tartrate-resistant acid phosphatase stain. For the in vivo study, male athymic BALB/cA Jc1-nu nude mice bearing human RCC cell line RBM1-IT4 cells were treated with YM529 and/or IFN-α. The biological activity of osteoclasts was evaluated using the pit formation assay. The antiangiogenetic effect by YM529 and/or IFN-α was analyzed using micro-vessel density and in situ mRNA hybridization. Osteoclast number in bone tumors was decreased in YM529-treated mouse. YM529 also inhibited osteoclast activity and proliferation in vitro, whereas basic fibroblast growth factor expressions and micro-vessel density within tumors were inhibited by IFN-α. Neither YM529 nor IFN-α alone significantly inhibited the growth of established bone metastatic tumors. Combined treatment with YM529 and IFN-α may be beneficial in patients with human RCC bone metastasis. Their effects are mediated by osteoclast recruitment inhibition and inactivation by YM529 and antiangiogenesis by IFN-α.

Oral squamous carcinoma cells secrete RANKL directly supporting osteolytic bone loss

OBJECTIVE

Local invasion of bone is a frequent complication of oral squamous cell carcinoma (OSCC). Development of these osteolytic lesions is mediated by osteoclasts. Receptor activation of NF-κB ligand (RANKL) signaling, counteracted by osteoprotegerin (OPG), regulates osteoclastogenesis. Previous studies in rodent models have demonstrated that inhibition of RANKL decreases tumor growth and lesions within bone. However, the contributory role of OSCC cells to this disease process has yet to be defined.

METHODS

RANKL expression was assessed in a panel of OSCC cell lines by qPCR, flow cytometry, and ELISA. Induction of osteoclastogenesis was assessed by co-culture with macrophages or with OSCC-derived conditioned medium. In an animal model of bone invasion, nude mice were injected intratibially with UMSCC-11B cells expressing a RANKL luciferase promoter to detect tumor-derived RANKL activity. Osteolytic lesions were analyzed by X-ray, micro-CT, and histological methods. RANKL expression was assessed in human OSCC tissues by immunohistochemistry.

RESULTS

We demonstrated that OSCCs express varied levels of all RANKL isoforms, both membrane-bound and soluble RANKL. Both co-culture and treatment with OSCC-conditioned media induced osteoclastogenesis. In mice, we demonstrated human RANKL promoter activity during bone invasion. Over the course of the experiment, animals suffered osteolytic lesions as RANKL-driven luciferase expression increased with time. After 8weeks, human-derived RANKL was detected in areas of bone resorption by immunohistochemistry. Similar epithelial RANKL expression was detected in human OSCC tissues.

CONCLUSION

These data demonstrate the ability of OSCCs to produce RANKL, directly altering the tumor microenvironment to increase osteoclastogenesis and mediate local bone invasion.

An orthotopic and osteolytic model with a newly established oral squamous cell carcinoma cell line

OBJECTIVE

Despite the availability of advanced clinical diagnostic systems, the overall 5-year survival rate for patients with oral squamous cell carcinoma (OSCC) has remained relatively poor over the past 2 decades. Appropriate animal models need to be developed according to the specific purpose of cancer research. However, most of the currently available oral cancer cell lines do not precisely reflect the characteristics of bone-invasive OSCC and cannot serve as suitable tools in the development of new therapeutic reagents against bone-invasive OSCC. Here, we assessed the orthotopic and osteolytic mouse model with newly established OSCC cell line.

DESIGN

We assessed the orthotopic and osteolytic mouse model using the newly established OSCC cells. In addition, the incidences of tumorigenesis and histopathological results were determined.

RESULTS

The newly established YD-39 cell line grows in a monolayer sheet and has highly invasive. The transplanted YD-39 cells developed stable tumours in the tongues and calvaria region of the nude mice. The tumours in nude mice grafted with YD-39 cells had a high incidence of transplantability in both mouse models tested and a similar morphology to their respective original tumour. Therefore, both animal models might be feasible animal models to assess the efficacy of anti-cancer drugs.

CONCLUSIONS

This type of animal model approach might be has the added advantage of potentially accelerating the biological discovery process.

Secretion of IL-6 and IL-8 from lysophosphatidic acid-stimulated oral squamous cell carcinoma promotes osteoclastogenesis and bone resorption

Lysophosphatidic acid (LPA) is a bioactive lipid with a growth factor-like activity on a large range of cell types. Several pieces of evidence raise the possibility that LPA may play an important role in bone metastasis. Bone is a frequent metastatic site for oral cancer. However, the role of LPA in the progression of oral cancer metastasis to the bone is poorly understood. Here, we provide evidence for the role of LPA in the progression of oral cancer bone metastases and its regulatory mechanism. LPA induced the secretion of IL-6 and IL-8 in oral squamous cell carcinoma (OSCC). LPA-stimulated secretion of IL-6 and IL-8 is partly dependent on the LPA and EGF receptor (EGFR) pathways. ERK1/2 and Akt-mediated NF-κB and AP-1 were responsible for the LPA-induced IL-6 and IL-8 secretion. Moreover, conditioned medium (CM) derived from the LPA-stimulated OSCC supported osteoclast formation in bone marrow-derived macrophages (BMMs). Neutralization against both human IL-6 and IL-8 suppressed osteoclast formation induced by CM derived from the LPA-stimulated OSCC. Direct treatment with recombinant IL-6 (rIL-6) and/or soluble IL-6 receptor (sIL-6R), or IL-8 (rIL-8) reproduced the effect of the CM derived from the LPA-stimulated OSCC on osteoclast formation. In addition, CM derived from the LPA-stimulated OSCC induced receptor activator of nuclear factor (NF)-κB ligand (RANKL) expression in human osteoblasts and direct treatment with rIL-6 and/or sIL-6R or rIL-8 mimicked the effect of the CM derived from the LPA-stimulated OSCC for RANKL expression. Taken together, LPA may be a potent inducer of osteolytic factor IL-6 and IL-8 in OSCC. LPA-induced IL-6 and IL-8 exerted propound effects on RANKL expression in osteoblast and thereby promoted osteoclast formation from osteoclast precursors.

Bone-derived SDF-1 stimulates IL-6 release via CXCR4, ERK and NF-kappaB pathways and promotes osteoclastogenesis in human oral cancer cells

Oral squamous cell carcinoma (SCC) has a striking tendency to invade to bone. The chemokine stromal cell-derived factor-1 (SDF-1) is constitutively secreted by osteoblasts and plays a key role in homing of hematopoietic cells to the bone marrow. Interleukin (IL)-6 plays an important role in osteoclastogenesis. Herein, we found that SDF-1α increased the secretion of IL-6 in cultured human SCC cells, as shown by reverse transcriptase–polymerase chain reaction and enzyme-linked immunosorbent assay. SDF-1α also increased the surface expression of chemokine receptor 4 (CXCR4) in SCC cells. CXCR4-neutralizing antibody, CXCR4-specific inhibitor (AMD3100) or small interfering RNA against CXCR4 inhibited SDF-1α-induced increase IL-6 production. The transcriptional regulation of IL-6 by SDF-1α was mediated by phosphorylation of extracellular signal-regulated kinases (ERKs) and activation of the nuclear factor-kappa B (NF-κB) components p65 and p50. The binding of p65 and p50 to the NF-κB element on the IL-6 promoter was enhanced by SDF-1α. In addition, IL-6 antibody antagonized the SCC-conditioned medium-increased osteoclastogenesis. These results suggested that SDF-1α from osteoblasts could induce release of IL-6 in human SCC cells via activation of CXCR4, ERK and NF-κB pathway and thereby promote osteoclastogenesis.

Distribution of macrophages, osteoclasts and the B-lymphocyte lineage in osteolytic metastasis of mouse mammary carcinoma

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.

Endoprosthetic elbow replacement in patients with solitary metastasis resulting from renal cell carcinoma

Renal cell carcinoma is one of the most common cancers, and solitary metastasis to bone occurs in 2.5% of these patients. Localization of solitary metastasis to the elbow joint is rarer still, and data about these patients are limited. Because, in these cases, metastasis presents with osteolytic bone destruction, radical removal of solitary lesions should be considered. The aim of this treatment is to control the tumor locally, to reduce pain, and to restore function. We describe 4 patients with a solitary metastasis to the elbow from renal cell carcinoma who had the tumor resected and were then fitted with a custom-made elbow prosthesis. After surgical reconstruction, all patients reported markedly reduced pain and had a good functional outcome. The literature and our experience indicate that the prognosis for patients with just a solitary metastasis is sufficiently encouraging to warrant the use of all surgical and oncologic treatment options, especially if the interval between the diagnosis of the primary tumor and the development of the metastasis is lengthy.

Characterization of bone metastases in patients with renal cell cancer

OBJECTIVE

To characterize the clinical features of bone metastases in patients with renal cell carcinoma (RCC) treated with interleukin-2 therapy. Bone lesions contribute to significant morbidity and mortality, and although present in up to half of patients with RCC, their behaviour and response to therapy have not been well characterized.

PATIENTS AND METHODS

We evaluated skeletal metastases in 19 patients with bone lesions who received either moderate- or high-dose interleukin-2 therapy. Data on bone disease, including location and number of bone lesions, need for bone-specific therapies and use of pain medications, were noted. The response of bone lesions to interleukin-2 was compared with the response of other systemic metastatic sites.

RESULTS

Skeletal metastases resulted in significant morbidity by causing pain (75%) and other complications requiring surgical and/or radiotherapeutic intervention (94%) before beginning interleukin-2 therapy. In most patients the response of bone lesions to interleukin-2 was similar to that in their other systemic sites. Treatment with interleukin-2 had no significant effect on the requirement for pain medication for bone pain. However, it may have prevented skeletal complications requiring surgery or radiotherapy. None of the patients had hypercalcaemia; there was no significant association between bone metastases and elevated alkaline phosphatase levels.

CONCLUSIONS

Skeletal metastases are a significant contributor to morbidity among patients with RCC. Bone lesions respond similarly to interleukin-2 therapy as other systemic sites. Bisphosphonates appear promising for these predominantly osteolytic lesions.

Targeted etanercept for treatment-refractory pain due to bone metastasis: two case reports

BACKGROUND

Parallel bodies of research suggest both a central role for osteoclasts in tumor-induced destruction of bone and the ability of biologic tumor necrosis factor-alpha (TNF-alpha) antagonists to attenuate the osteoclast-mediated bone destruction that accompanies a variety of nonmalignant disorders. Additional studies have implicated TNF-alpha in the promotion of osteoclast-mediated malignant osteolysis and the pathogenesis of neuropathic pain. TNF-alpha antagonists have the potential to interfere in both processes.

OBJECTIVE

This article reviews the cases of 2 patients with treatment-refractory pain due to cancer metastases to bone who were given targeted injections of the biologic anti-TNF agent etanercept based on its potential to interfere directly with both malignant activation of osteoclasts and neuropathic pain.

METHODS

One patient had a diagnosis of non-small cell lung cancer and the other had a diagnosis of breast cancer. Both presented with treatment-refractory pain due to bone metastases. The 2 patients received etanercept 25 mg by targeted SC injection in anatomic proximity to the site of spinal metastasis for relief of their treatment-refractory pain.

RESULTS

Both patients experienced rapid, substantial, and sustained relief of chronic refractory pain at the treatment site after targeted administration of etanercept. Symptomatic improvement was correlated with objective measures of improvement, including weight gain in 1 patient and decreased uptake of radioactive tracer at the targeted site on positron emission tomography in the other.

CONCLUSIONS

Etanercept delivered by targeted SC injection may be of clinical benefit in selected patients with treatment-refractory pain caused by bone metastases. Clinical trials are needed to define the potential benefit of biologic TNF-alpha antagonists in the treatment and prevention of malignant osteolysis.

Osteoclasts are required for bone tumors to grow and destroy bone

It has been hypothesized that bone resorption during tumor osteolysis is performed by osteoclasts. Data supporting this hypothesis have been provided from analysis of human biopsy specimens obtained from sites of tumor osteolysis, as well as from experimentation with in vivo animal models. Experiments in this report take this concept one step further by testing the hypothesis that osteoclasts are required for bone tumors to grow and destroy bone. To test this hypothesis, the influence of an osteolytic sarcoma tumor, NCTC clone 2472 (2472), on bone was studied in animals that are osteoclast deficient (microphthalmic, strain B6C3Fe-a/a-Mitf(mi)) but whose osteoclast deficiency can be reversed following bone marrow transplantation. Femora of these mice and unaffected wild-type siblings were injected with 10(5) 2472 cells, and after 14 days the femora were analyzed by radiographic and histomorphometric analysis. Macroscopic tumor, tumor-induced osteolysis, and increased osteoclast number were noted in femora of normal mice but not in femora of osteoclast-deficient mice (p < 0.001). Bone marrow transplantation converted osteoclast-deficient mice to mice with femora that contained osteoclasts in 4 weeks. Femora of these mice were then injected with 10(5) 2472 tumor cells; after 14 days, in contrast to the findings in the original osteoclast-deficient mice, macroscopic tumor was present, tumor-induced osteolysis was noted on roentgenograms, and osteoclast number was increased when tumor-bearing limbs were compared with sham-injected limbs (p < 0.001). These data prove the hypothesis that osteoclasts are required for 2472 tumor-induced osteolysis, and they introduce the exciting possibility that osteoclasts are also required for tumors to grow in bone.

Histomorphometric analysis of osteoclastic resorption in bone directly invaded by gingival squamous cell carcinoma

Whole frontal sections of the mandibular bone from 18 patients with gingival squamous cell carcinoma showing direct bone invasion were prepared for histometrical analysis by a non-decalcified grinding method. The osteoclast cytoplasmic area in tumor sites was larger and its relative frequency distribution was broader than that of osteoclasts in non-tumor sites. The index of bone resorption was significantly increased, while that of bone formation was decreased, in the tumor sites compared to the non-tumor sites (P < 0.01). In the tumor sites, the indices of bone resorption and formation in the group showing greatest chemotherapy and radiation therapy effects (CRE) were significantly different from those in the group with low CRE (P < 0.01). A history of irradiation therapy was associated with significantly decreased bone resorption (P < 0.05).

Human breast cancer induces osteoclast activation and increases the number of osteoclasts at sites of tumor osteolysis

The cellular mechanism through which osseous breast cancer metastases induce the focal destruction of bone (tumor osteolysis) is unknown. An athymic mouse model designed for the study of tumor osteolysis was developed and the influence of two human breast cancer tumors on bone was studied. Tumor-induced osteolysis occurred between 7 and 10 weeks after inoculation of mouse femora with MDA-MB-231 or MDA-MB-435s breast cancer cells. An increase in osteoclast number and an increase in osteoclast size (area) were detected when tumor-bearing and sham-injected limbs were compared. In vitro analysis of the influence of the tumor-conditioned medium on osteoclast-mediated bone resorption revealed that this conditioned medium stimulated the resorption by increasing both the number of osteoclasts bound to bone and the number of bone resorption pits formed per osteoclast. In addition, in vitro analysis of the influence of breast cancer tumor cells on osteoclast formation or survival, or both, demonstrated that breast cancer cells induced a dramatic increase in the number of osteoclasts detected in culture. Taken in total these findings suggest that human breast cancer tumors induce osteolysis by enhancing osteoclast adherence to bone, stimulating osteoclast-mediated bone resorption and either prolonging the survival of osteoclasts or increasing osteoclast formation.

Localized, tumor-associated osteolysis involves the recruitment and activation of osteoclasts

The cellular and biochemical mechanisms that direct destruction of bone at the site of tumor osteolysis are unknown. In order to understand this process better, a murine model designed for the study of tumor osteolysis was developed and the influence of osteolytic and nonosteolytic tumors on bone was investigated. Tumors developed following femoral intramedullary injection of sarcoma (2472) and melanoma (G3.26) cell lines; however, only tumors from the 2472 cell line caused osteolysis. It was determined that 2472 tumor-induced osteolysis commenced 6 days after the femora had been inoculated with 2472 cells. There were more osteoclasts per millimeter of bone surface in 2472 tumor-bearing limbs (16.7 +/- 5.0) than in sham-injected limbs (3.8 +/- 0.9) (p < 0.015). In addition, an increase in the osteoclast size (area) was detected in 2472 tumor-bearing limbs: 412 +/- 65 micron2 compared with 187 +/- 17 micron2 (p < 0.01). In vitro bone resorption experiments indicated that 2472 tumor cells had a limited ability to destroy bone in comparison with macrophages and osteoclasts. Taken in total, these findings define a model that is useful for the study of tumor osteolysis, and the data from analyses of the model demonstrate that the cellular mechanisms responsible for 2472 tumor-induced osteolysis include both an increase in the number of osteoclasts and activation of mature osteoclasts.