Osteolytic Skeletal Metastases Research Articles

Osteoclast Signal Transduction During Bone Metastasis Formation.

Osteoclasts are myeloid lineage-derived bone-resorbing cells of hematopoietic origin. They differentiate from myeloid precursors through a complex regulation process where the differentiation of preosteoclasts is followed by intercellular fusion to generate large multinucleated cells. Under physiological conditions, osteoclastogenesis is primarily directed by interactions between CSF-1R and macrophage colony-stimulating factor (M-CSF, CSF-1), receptor activator of nuclear factor NF-κB (RANK) and RANK ligand (RANKL), as well as adhesion receptors (e.g., integrins) and their ligands. Osteoclasts play a central role in physiological and pathological bone resorption and are also required for excessive bone loss during osteoporosis, inflammatory bone and joint diseases (such as rheumatoid arthritis) and cancer cell-induced osteolysis. Due to the major role of osteoclasts in these diseases the better understanding of their intracellular signaling pathways can lead to the identification of potential novel therapeutic targets. Non-receptor tyrosine kinases and lipid kinases play major roles in osteoclasts and small-molecule kinase inhibitors are emerging new therapeutics in diseases with pathological bone loss. During the last few years, we and others have shown that certain lipid (such as phosphoinositide 3-kinases PI3Kβ and PI3Kδ) and tyrosine (Src−family and Syk) kinases play a critical role in osteoclast differentiation and function in humans and mice. Some of these signaling pathways shows similarity to immunoreceptor-like receptor signaling and involves important other enzymes (e.g., PLCγ2) and adapter proteins (such as the ITAM−bearing adapters DAP12 and the Fc-receptor γ-chain). Here, we review recently identified osteoclast signaling pathways and their role in osteoclast differentiation and function as well as pathological bone loss associated with osteolytic tumors of the bone. A better understanding of osteoclast signaling may facilitate the design of novel and more efficient therapies for pathological bone resorption and osteolytic skeletal metastasis formation.

Skeletal metastasis of carcinoid tumors: Two case reports and review of the literature.

Carcinoid tumors are neuroendocrine neoplasms derived from enterochromaffin cells. Skeletal metastases from carcinoid tumors are considered to be extremely rare. In this study, we present two cases of carcinoid tumors that metastasized to the bone. Furthermore, we review 50 published case reports and reveal the features of skeletal metastasis of carcinoid tumors. The first case involved a 59-year-old man with a history of multiple metastases of a lung carcinoid tumor. The patient complained of back pain and numbness in the lower limbs. Magnetic resonance imaging revealed metastases in the thoracic spine. A spinal decompression was performed and the symptoms were resolved. The second case involved a 74-year-old man had been diagnosed with a lung carcinoid tumor 15 years previously and complained of left thigh pain. A radiograph showed osteolytic lesions in the shaft of the left femur. We repaired the femur using an intramedullary nail following curettage of the tumor. A radiograph of the femur revealed a callus on the pathological fracture. The patient was able to walk using a crutch 3 months after surgery. We reviewed 50 cases that described skeletal metastasis from carcinoid tumors. The average age of the patients was 54.9 years and 33 patients (66%) were male. The most common site of skeletal metastasis was the spine. We also investigated the survival rate of patients who developed skeletal metastasis from carcinoid tumors. The findings showed that survival of patients who developed osteolytic skeletal metastasis was worse than that of patients who developed osteosclerotic skeletal metastasis.

Metastatic Lymph Node and Osteolytic Skeletal Metastasis Detected by FDG-PET in an Endoscopy-Diagnosed Early-Stage Esophageal Cancer

A 50-year-old man who had chronic peptic ulcer disease with an early-stage squamous cell carcinoma in the lower third of the esophagus. The primary tumor was not visualized on an FDG-PET study. However, a paraaortic lymphnode metastasis in the upper abdomen was demonstrated in this initial staging. The patient underwent an operation at another hospital. The postoperative staging was classified as stage I (T1N0M0: tumor invasion limited to submucosa, no regional lymph node metastasis 0/47, no distant metastais). One year later, a protruding firm mass developed over the sternum. Follow-up FDG-PET showed foci with intense activity in the sternal and epigastric regions. Although conventional MDP bone scan did not clearly show the lesion, an osteolytic skeletal metastasis to the sternum and progressive enlargement of the metastatic paraaortic lymph node were identified by PET.

Establishment of a Transplantable Rat Pulmonary Carcinoma-Derived Cell Line (IP-B12) as a New Model of Humoral Hypercalcemia of Malignancy and Bone Metastasis

A cloned cell line (IP-B12) derived from a transplantable rat pulmonary carcinoma (IP), of which neoplastic cells produce parathyroid hormone-related protein (PTHrP), was established. Tumors induced in syngeneic F344 rats by intraperitoneal injection of IP-B12 cells had features of pulmonary adenocarcinomas, consisting of neoplastic cells immunopositive to PTHrP. The IP-B12 tumor-bearing rats developed severe emaciation and hypercalcemia, with a marked elevation of plasma PTHrP level; there was an increase in osteoclastic areas of the femur and calcium depositions in systemic organs, indicating progression to humoral hypercalcemia of malignancy (HHM) in the tumor-bearing rats. In addition, the injection of IP-B12 cells into the left cardiac ventricle of syngeneic rats resulted in osteolytic skeletal metastases in the long bones and vertebrae. In the metastatic lesions, histologically, neoplastic cells showed an immunopositive reaction to PTHrP, and a prominent osteoclastic activity was seen; bone lesions, including osteolysis, fracture, and nerve compression as well as replacement of bone marrow cells by proliferated tumor cells were similar to those reported in human cancer patients with bone metastases. IP-B12 is a new animal model for HHM and osteolytic bone metastases, and will become a useful tool for studies on the pathogenesis and therapeutic strategies for such conditions.

The Role of Bisphosphonates in Breast Cancer Management: Review Article

SummaryBone metastases are a common problem in the management of breast cancer and are associated with considerable morbidity. Bone pain, hypercalcaemia, fractures and cord compression all occur requiring interventions such as analgesia, radiotherapy and surgery. Bisphosphonates are drugs that are active in the bone microenvironment. Their effects on osteoclasts are well described: they potently inhibit osteoclast mediated bone resorption by delaying the maturation of immature osteoclasts and by directly inducing osteoclast apoptosis. It has been known for some time that bisphosphonates, in combination with intravenous rehydration, effectively treat hypercalcaemia associated with solid malignancies. It has now been demonstrated in clinical trials in breast cancer patients that regular bisphosphonate administration reduces the morbidity associated with osteolytic skeletal metastases. There is an emerging suggestion from clinical trial work that bisphosphonates may be able to reduce or delay the development of skeletal metastases although this remains controversial as the three published trials present conflicting results. The more potent third-generation bisphosphonates, such as zoledronate, are now being tested for each of these indications with promising results and may replace other bisphosphonates in the future. Laboratory studies have recently demonstrated that bisphosphonates have direct cytotoxic effects against breast cancer cells in vitro, inducing apoptosis and preventing adhesion to bone. This adds support to the hypothesis that bisphosphonates may have a genuine beneficial effect in the adjuvant setting.

Over‐production of parathyroid hormone–related peptide results in increased osteolytic skeletal metastasis by prostate cancer cells In vivo

Prostate carcinoma is one of the most common malignancies affecting males, resulting in a high rate of morbidity and mortality. This hormone-dependent malignancy is characteristically associated with a high incidence of osteoblastic skeletal lesions. However, osteolytic lesions invariably accompany blastic ones. In the current study, we assessed the role of parathyroid hormone–related peptide (PTHRP), a potent bone-resorbing agent, in contributing to bone breakdown and prostatic skeletal metastasis using a syngeneic rat prostate cancer model. The full-length cDNA encoding rat PTHRP was subcloned as a Hind III insert in the sense orientation into the mammalian expression vector pRc-CMV to generate the expression vector pRc-PTHRP-S. Both control and experimental plasmids were stably transfected into low PTHRP-producing Dunning R3227, Mat Ly Lu rat prostate cancer cells. Following antibiotic selection, monoclonal cell lines expressing the highest amount of PTHRP mRNA and immunoreactive PTHRP were selected as experimental tumor cells for further analysis. Increased PTHRP production by these cells had no significant effect in vitro on the invasive capacity of these cells. Control and experimental cells were inoculated s.c. into the right flank or by the intracardiac (i.c.) route into the left ventricle of inbred male Copenhagen rats. No skeletal metastases occurred after s.c. injection with either cells. In contrast, i.c. inoculation led to lumbar vertebra metastasis and consequent hind-limb paralysis. Furthermore, histological examination of skeletal metastases in experimental animals showed a marked increase in osteoclastic activity. Our results demonstrate that PTHRP can increase osteoclastic osteolysis in the presence of focal osseous prostate cancer metastases and may contribute to the lytic lesions which generally accompany osteoblastic lesions in prostate cancer. Int. J. Cancer 80:257–264, 1999. © 1999 Wiley-Liss, Inc.

Over-production of parathyroid hormone-related peptide results in increased osteolytic skeletal metastasis by prostate cancer cellsIn vivo

Prostate carcinoma is one of the most common malignancies affecting males, resulting in a high rate of morbidity and mortality. This hormone-dependent malignancy is characteristically associated with a high incidence of osteoblastic skeletal lesions. However, osteolytic lesions invariably accompany blastic ones. In the current study, we assessed the role of parathyroid hormone-related peptide (PTHRP), a potent bone-resorbing agent, in contributing to bone breakdown and prostatic skeletal metastasis using a syngeneic rat prostate cancer model. The full-length cDNA encoding rat PTHRP was subcloned as a Hind III insert in the sense orientation into the mammalian expression vector pRc-CMV to generate the expression vector pRc-PTHRP-S. Both control and experimental plasmids were stably transfected into low PTHRP-producing Dunning R3227, Mat Ly Lu rat prostate cancer cells. Following antibiotic selection, monoclonal cell lines expressing the highest amount of PTHRP mRNA and immunoreactive PTHRP were selected as experimental tumor cells for further analysis. Increased PTHRP production by these cells had no significant effect in vitro on the invasive capacity of these cells. Control and experimental cells were inoculated s.c. into the right flank or by the intracardiac (i.c.) route into the left ventricle of inbred male Copenhagen rats. No skeletal metastases occurred after s.c. injection with either cells. In contrast, i.c. inoculation led to lumbar vertebra metastasis and consequent hind-limb paralysis. Furthermore, histological examination of skeletal metastases in experimental animals showed a marked increase in osteoclastic activity. Our results demonstrate that PTHRP can increase osteoclastic osteolysis in the presence of focal osseous prostate cancer metastases and may contribute to the lytic lesions which generally accompany osteoblastic lesions in prostate cancer.

The effect of temperature on MR relaxation times and signal intensities for human tissues

T1 andT2 relaxation times were measured on human tissue samples of adipose tissue, muscle, bone marrow and osteolytic skeletal metastases at temperatures ranging from +37°C to −10°C. Relative signal intensities forT1, proton density andT2-weighted imaging sequences were also calculated.T1 andT2 of adipose tissue decreased almost linearly with decreasing temperature while for muscle, bone marrow and metastasesT1 andT2 decreased slightly to moderately, with temperature reduction to about −5 °C at which temperature a sudden marked decrease occurred. Calculated signal intensities showed a decrease in image contrast with temperature reduction and reversal of contrast between adipose tissue and the other tested tissues with all imaging sequences at temperatures around 0°C.

A 16-Year-Old Girl with Invasive Carcinoma of the Vulva

We present a 16-year-old girl with vulvar squamous cell carcinoma. The patient initially received a radical treatment because of lymph-node dissemination. However, recurrent disease erupted a little more than one year after the initial treatment, with metastases in the right lung and multiple osteolytic skeletal metastases. Despite aggressive treatments with chemotherapy the patient died about 2 years after the initial diagnosis. An aggressive radical treatment must be chosen for cases of invasive vulvar carcinoma, irrespective of the patient's age.