A murine model of experimental metastasis to bone and bone marrow

Bone is a common site of metastasis in human cancer. A major impediment to understanding the pathogenesis of bone metastasis has been the lack of an appropriate animal model. In this paper, we describe an animal model in which B16 melanoma cells injected in the left cardiac ventricle reproducibly colonize specific sites of the skeletal system of mice. Injection of 10(5) cells resulted in melanotic tumor colonies in most organs, including the skeletal system. Injection of 10(4) or fewer cells resulted in experimental metastasis almost entirely restricted to the skeletal system and ovary. In contrast, i.v. injection of 10(5) cells resulted in tumor colonies in the lung only. Left cardiac injection of 10(2) cells caused bone colonization, but the same number of cells injected i.v. did not colonize the lung. The number of bones with tumor colonies increased with increasing number of cells injected. Melanotic tumor colonies in the bone were characteristically distributed in the metaphysis of long bones and in the periphery of flat bones. Most animals developed paraplegia due to spinal cord compression by bony metastasis to the spine. Tumor colonization of bone occurred only in regions of bone containing hematopoietic bone marrow. This suggests that the injected tumor cells lodge, survive in the hematopoietic bone marrow environment, and grow to destroy adjacent bone. This experimental model of metastasis to bone will facilitate future studies of the pathophysiology and treatment of bone and bone marrow metastasis.     

Genes associate with abnormal bone cell activity in bone metastasis

Bone is one of the most frequent sites of metastasis in patients with malignancies. Up to 90?% of patients with multiple myeloma, and 60?% to 75?% patients with prostate cancer and breast cancer develop bone metastasis at the later stages of their diseases. Bone metastases are responsible for tremendous morbidity in patients with cancer, including severe bone pain, pathologic fractures, spinal cord and nerve compression syndromes, life-threatening hypercalcemia, and increased mortality. Multiple factors produced by tumor cells or produced by the bone marrow microenvironment in response to tumor cells play important roles in activation of osteoclastic bone resorption and modulation of osteoblastic activity in patients with bone metastasis. In this chapter, we will review the genes that play important roles in bone destruction, tumor growth, and osteoblast activity in bone metastasis and discuss the potential therapies targeting the products of these genes to block both bone destruction and tumor growth.     

Spinal cord compression produced by osteomyelitis mimicking spinal epidural metastasis.

Spinal cord compression is a common neurological emergency. The causes of spinal cord compression may include primary or (more frequently) metastatic tumor, infections, trauma, and vertebral or intervertebral disc disease. In most instances the underlying etiology is known or easily ascertained. We present here three recent cases in which patients presented with spinal cord compression and lytic bone lesions suggesting metastatic cancer. In these cases, vertebral osteomyelitis was found to be the cause.     

Renal cell carcinoma bone metastasis—elucidating the molecular targets

The development of bone metastasis from renal cell carcinoma (RCC) signals a transition to a terminal state for the patient with previously isolated disease. These patients may suffer the morbidity of severe, persistent pain, pathologic fractures, and spinal compression from vertebral metastasis before they succumb to their cancer. Although recent advancements have been made in the understanding of breast and prostate bone metastasis, there has been less knowledge in the area of metastatic RCC to the skeleton. This particular cancer in bone remains relatively resistant to standard forms of treatment such as radiation and chemotherapy. A better understanding of the biology of RCC bone metastasis is critically needed in order to improve treatment. Bone-derived cell lines and an experimental animal model have been developed in order to explore the relevant mechanisms of how RCC cells survive within and destroy the bone. This review will focus on the growth factor signaling pathways most important for the RCC-stimulated osteoclast-mediated bone destruction, namely the epidermal growth factor receptor (EGF-R) and transforming growth factor-β receptor (TGF-βR) pathways. By inhibiting these receptors, growth of RCC within the bone is decreased which, directly or indirectly, decreases bone destruction.     

Responsiveness of human prostate carcinoma bone tumors to interleukin-2 therapy in a mouse xenograft tumor model.

We have tested an immunotherapy approach for the treatment of metastatic prostate carcinoma using a bone tumor model. Human PC-3 prostate carcinoma tumor cells were heterotransplanted into the femur cavity of athymic Balb/c nude mice. Tumor cells replaced marrow cells in the bone cavity, invaded adjacent bone and muscle tissues, and formed a palpable tumor at the hip joint. PC-3/IF cell lines, generated from bone tumors by serial in vivo passages, grew with faster kinetics in the femur and metastasized to inguinal lymph nodes. Established tumors were treated with systemic interleukin-2 (IL-2) injections. IL-2 significantly inhibited the formation of palpable tumors and prolonged mouse survival at nontoxic low doses. Histologically IL-2 caused vascular damage and infiltration of polymorphonuclear cells and lymphocytes in the tumor as well as necrotic areas with apoptotic cells. These findings suggest destruction of tumor cells by systemic IL-2 therapy and IL-2 responsiveness of prostate carcinoma bone tumors.     

Management of metastatic spinal cord compression

Metastatic spinal cord compression, diagnosed in 3-7% of cancer patients, is one of the most dreaded complications of metastatic cancer. It is an oncologic emergency, which must be diagnosed early and treated promptly to achieve the best results and avoid progressive pain, paralysis, sensory loss and sphincter incontinence. Patients who are ambulatory at the time of the diagnosis have a higher probability of obtaining good response to treatment and a longer survival. In clinical practice, back pain accompanies metastatic spinal cord compression in most cases, even in patients with no neurologic deficits. Magnetic resonance imaging is the best tool for diagnosing metastatic spinal cord compression and is able to identify spinal cord compression in 32-35% patients with back pain, bone metastases and normal neurologic examination. Moreover, magnetic resonance imaging gives the extension of the lesion, can diagnose other unsuspected clinical metastatic spinal cord compression sites, and is useful for the radiation oncologist in defining the target volume. Radiotherapy is the treatment of choice in most cases, whereas surgery is advised only in selected patients (ie, if stabilization is necessary, if radiotherapy has already been given in the same area, when vertebral body collapse causes bone impingement on the cord or nerve roots, when there are diagnostic doubts, or when computed tomography-guided percutaneous vertebral biopsy cannot be performed). Laminectomy should be abandoned in favor of more aggressive surgery (ie, posterior, anterior, and/or lateral approach, tumor mass resection, and stabilization of the spine). Generally, radiotherapy must be administered 7-10 days after surgery. The optimal radiation schedule has not been defined. However, as recently suggested by some clinical trials, even the hypofractionated radiotherapy regimens are effective and can be used without increasing radiation-induced myelopathy. Moderate doses of dexamethasone should be used in the early phases of therapy. After radiotherapy, spinal recurrence is generally found in sites different from the first compression area. A close post-treatment follow-up is suggested using clinical parameters (pain, motor and sphincter function), and magnetic resonance imaging should be performed only when a second metastatic spinal cord compression and/or myelopathy are clinically suspected.     

Site-specific experimental metastasis patterns of two human breast cancer cell lines in nude rats.

Animal models for breast cancer metastasis are valuable tools for studying mechanisms of metastasis and for preclinical testing of anti-metastatic therapy regimens. Using MA-11 and MT-1, two oestrogen and progesterone receptor-negative human breast cancer cell lines, we developed new models in nude rats with patterns of experimental metastasis resembling those frequently observed in humans. MA-11 cells showed a clear preference for growth in the CNS. Fourteen of 15 animals injected with MA-11 cells into the left ventricle of the heart developed hind-leg paralysis, and tumours were observed in the spinal cord. MT-1 cells consistently exhibited bone/bone marrow metastases after intracardial injection, in addition to tumours in the brain and spinal cord. When injected into the cisterna magna, both cell lines gave rise to leptomeningeal neoplastic disease. Injection of MA-11 cells into the tibial bone marrow resulted in tumours in only 2 of 13 rats, whereas all animals injected with MT-1 cells developed tumours. Only 2 of 6 rats injected i.v. with MA-11 cells developed lung colonies compared with all 9 animals injected with MT-1 cells. Cell-surface expression of the following was examined: EGP2; MUC1; EGFr; E- and N-cadherin; the alpha2, alpha3, alpha5, beta1 and beta4 integrins; c-erb-B2; and N-CAM. c-erb-B2 was expressed in a higher percentage of the bone-metastasizing MT-1 cells than the MA-11 cells, whereas E-cadherin was expressed in MA-11 but not MT-1 cells. In animals injected with MA-11 and MT-1 cells in the left cardiac ventricle, treatment with cisplatin and doxorubicin did not improve survival. In summary, these clinically relevant animal models may be used for studies related to site-specific growth and metastasis and for assessing effects of experimental therapy against human breast cancer.     

应用Pyramesh钛网融合器植骨加Orion钛板内固定治疗颈椎椎体肿瘤

目的：探讨经颈前路切除颈椎椎体肿瘤后，利用Pyramesh钛网融合器（简称钛网）植骨修复骨缺损，Orion钛板内固定的方法治疗颈椎肿瘤的临床价值。方法：对9例颈椎肿瘤患行经颈前路椎体肿瘤切除，骨缺损处置入钛网支撑、植骨融合，椎前Orion钛板内固定。结果：9例患经过6-24个月的随访，无内固定物断裂、松动、脱出，植骨融合满意，无严重颈肩痛及颈椎不稳，无因肿瘤复发造成继发的颈椎骨折及脊髓压迫等并发症。结论：钛网植骨加Orion钛板内固定治疗颈椎椎体肿瘤，可充分保证固定节段的稳定性，植骨融合好，并可防止因肿瘤复发造成继发的颈椎骨折及脊髓压迫。     

Two autopsy cases of intramedullary spinal cord metastasis

Two autopsy cases of intramedullary metastasis to the spinal cord from small cell lung cancer and seminoma of the testis are reported and a review of the literature is presented. Rather than lung cancer, the most common primary tumor of this rare intramedullary spinal cord metastasis is seminoma of the testis. In our case, we posit the occurrence of hematogenous spread via arterial and vertebral venous system.     

Prevalence of Prostate Cancer Metastases after Intravenous Inoculation Provides Clues into the Molecular Basis of Dormancy in the Bone Marrow Microenvironment

Bone is the preferred metastasis site of advanced prostate cancer (PCa). Using an in vivo murine model of human PCa cell metastasis to bone, we noted that the majority of animals that develop skeletal metastasis have either spinal lesions or lesions in the bones of the hindlimb. Much less frequently, lesions develop in the bones of the forelimb. We therefore speculated whether the environment of the forelimb bones is not permissive for the growth of PCa. Consequently, data on tumor prevalence were normalized to account for the number of PCa cells arriving after intravascular injection, marrow cellularity, and number of hematopoietic stem cell niches. None of these factors were able to account for the observed differences in tumor prevalence. An analysis of differential gene and protein levels identified that growth arrest specific-6 (GAS6) levels were significantly greater in the forelimb versus hindlimb bone marrow. When murine RM1 cells were implanted into subcutaneous spaces in immune competent animals, tumor growth in the GAS6^-/- animals was greater than in GAS6^+/+ wild-type animals. In an osseous environment, the human PC3 cell line grew significantly better in vertebral body transplants (vossicles) derived from GAS6^-/- animals than in vossicles derived from GAS6^+/+ animals. Together, these data suggest that the differences in tumor prevalence after intravascular inoculation are a useful model to study the molecular basis of tumor dormancy. Importantly, these data suggest that therapeutic manipulation of GAS6 levels may prove useful as a therapy for metastatic disease.     

Myeloma appearance after local external beam radiotherapy jet: Is it a new entity?

Multiple myeloma, also known as Kahler's disease, is a cancer of plasma cells that abnormally accumulate in bone marrow. Radiation therapy may be indicated in multiple myeloma to relieve pain, alleviate spinal cord compression or reduce tumor mass. We report the case of a patient presenting a multiple myeloma, treated with radiation therapy for a spinal cord compression, who developed, eleven months later, an in-field subcutaneous relapse. We called this phenomenon myeloma appearance after local external beam radiotherapy jet (MAALEJ). A review of literature was performed trying to explain this uncommon relapse feature.     

An efficient method for establishing murine tumor cell lines

Tumor cells were cultured in RPMI1640 medium with 16% fetal calf serum and 5% conditioned medium of PHA-stimulated murine spleen cells. After cloning, the tumor cells were reinoculated into normal susceptible mouse. When tumor developed, they grew easily in subsequent cultures in vitro, thus establishing tumor cell lines. By this method, 5 leukemia cell lines and 2 tumor cell lines have been established.     

Giant cell tumor in Paget's disease of bone: familial and geographic clustering.

Four patients with benign giant cell tumor and one patient with probable benign giant cell tumor associated with Paget's disease of bone are reported. The familial and geographic clustering of these cases is unique in that three patients were related and all patients traced ancestral roots to the same area of southern Italy. Tumors arose from the cranial or facial bones in three patients and from vertebral bodies in two patients. All caused symptoms by local compression, and treatment by curettage or radiotherapy was successful in all patients. Three separate tumors in one patient shrank dramatically in response to treatment with high doses of dexamethasone, and one patient whose tumor caused spinal cord compression showed marked improvement in neurologic function on therapy with dexamathasone.     

Model system for removing neuroblastoma cells from bone marrow using monoclonal antibodies and magnetic immunobeads

Variables effecting removal of neuroblastoma cells from bone marrow using monoclonal antibodies and magnetic immunobeads were studied. Human neuroblastoma cell lines were labeled with the supravital DNA stain Hoechst 33342, seeded into normal bone marrow, incubated with monoclonal antibodies recognizing neuroblastoma cell surface antigens (HSAN 1.2, antibody 459, antibody 390, BA-1, and Leu-7), and then mixed with magnetic microspheres coated with goat anti-mouse immunoglobulin. Tumor cells that attached to the magnetic immunobeads were then removed from the marrow with magnets. The efficacy of tumor cell removal depended on the amount of monoclonal antibody bound to tumor cells and the immunobead/tumor cell ratio. In addition, two cycles of purging with both monoclonal antibodies and immunobeads was superior to one cycle. Using a cocktail of the five antibodies, 3 to 4 logs of tumor cells could be depleted from marrow with good recovery of viable hematopoietic cells.     

Spinal Epidural Involvement in Haematological Tumors: Clinical Features and Therapeutic Options

Haematological malignancies that may cause epidural spinal cord compression (SCC) include plasma cell dyscrasias, lymphomas and infrequently leukemias. Bone lesions are the major clinicopathologic manifestations in plasma cell dyscrasias but are evident in less than 30% of patients with SCC due to lymphomas. The incidence of SCC in solitary plasmacytomas is between 43 to 71%, in contrast to 7.4 to 16% in multiple myeloma where vertebral involvement is always present. The incidence of SCC in Hodgkin's disease and in non-Hodgkin's lymphomas is about 4 and 2.5% respectively. Spinal computed tomography, myelography and magnetic resonance imaging serve for establishing a definite diagnosis, assessment of tumor location within the spinal canal, delineation of the involved spinal levels, evaluation of spinal stability and for detection of extraosseous paravertebral extension. Treatment planning is based on the information obtained above, combined with clinical considerations. The primary modalities of therapy are radio- and chemotherapy. Surgery is reserved for those cases presenting with SCC when tissue diagnosis is unavailable, recurrence of SCC after previous irradiation and for spinal instability or compression of the neural elements by impinging bone fragments.     

Spinal epidural involvement in haematological tumors: clinical features and therapeutic options

Haematological malignancies that may cause epidural spinal cord compression (SCC) include plasma cell dyscrasias, lymphomas and infrequently leukemias. Bone lesions are the major clinicopathologic manifestations in plasma cell dyscrasias but are evident in less than 30% of patients with SCC due to lymphomas. The incidence of SCC in solitary plasmacytomas is between 43 to 71%, in contrast to 7.4 to 16% in multiple myeloma where vertebral involvement is always present. The incidence of SCC in Hodgkin's disease and in non-Hodgkin's lymphomas is about 4 and 2.5% respectively. Spinal computed tomography, myelography and magnetic resonance imaging serve for establishing a definite diagnosis, assessment of tumor location within the spinal canal, delineation of the involved spinal levels, evaluation of spinal stability and for detection of extraosseous paravertebral extension. Treatment planning is based on the information obtained above, combined with clinical considerations. The primary modalities of therapy are radio- and chemotherapy. Surgery is reserved for those cases presenting with SCC when tissue diagnosis is unavailable, recurrence of SCC after previous irradiation and for spinal instability or compression of the neural elements by impinging bone fragments.     

Giant cell tumors of synovium (Pigmented villonodular synovitis) involving the vertebral column

Giant cell tumors of synovium (pigmented villonodular synovitis) involving the vertebral column recently have been seen in two women: the third and fourth cases to be reported in the English-language literature. Unlike the previously reported cases, both these tumors grew outside the dura and produced symptoms of spinal cord compression. The first case involved lumbar vertebrae 5 and 6; the second, lumbar vertebrae 2 and 3. Even though initial resection of both tumors was incomplete, the patients improved postoperatively. One tumor was known to be unresectable at the time of surgery. In the other patient, a recurrence of symptoms required second and third resections 4 and 8 months after the first, respectively. Although synovial giant cell tumors rarely metastasize, the rate of local recurrence is high, especially if excision is incomplete. For this reason, close follow-up of patients with lesions in the spinal column is indicated. Increased physician awareness that synovial giant cell tumors can occur in the spine will help to ensure that these tumors are not misdiagnosed in this location.     

Anterior approach to the second thoracic vertebral body for surgical treatment (vertebrectomy, bone grafting, and titanium alloy plate fixation)

The surgical approach to the second thoracic vertebral body is difficult from the anterior side. A 38-year-old woman suffering from plasmacytoma in the second thoracic vertebra showed paraplegia for 2 weeks prior to surgery. X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) examinations indicated breakdown of the second thoracic vertebral body and arch, associated with spinal cord compression. A ^99mTc bone scintigram showed accumulation only in the second thoracic vertebra. After one course of chemotherapy with cyclophosphamide and prednisone (CP protocol), surgery was carried out. The incision was made on the right side of the anterior of the neck, from the middle half of the sternocleidomastoideus along the anterior edge to the jugular notch of the sternum. After cutting the platysma, severing the sternohyoideus, splitting the sternothyroid muscle, and forming a compartment between the esophagus and vagina carotica, we extended the incision to the sternum. Without wedging the sternum, we separated tissue from the posterior of the sternum to the second and third thoracic vertebrae, excised the second thoracic vertebra to expose the hard spinal meninges, and removed the tumor in the vertebral canal to release the compression on the spinal cord. An autogeneous bone graft, taken from the right ilium (1.5 × 1.5 × 3 cm in size), was implanted between the first and third thoracic vertebrae, and a spinal titanium alloy plate was used to increase fixation between the first and third thoracic vertebrae from the front. During the surgery, 800 ml of blood was transfused. On the fifth postsurgical day, the patient could walk normally with a neck collar, and the paraplegia was completely alleviated, with no complications. Received: October 4, 2000 / Accepted: May 25, 2001     

Spinal cord compression in widely metastatic Wilms' tumor. Paraplegia in two children with anaplastic Wilms' tumor.

Spinal cord compression in Wilms' tumor is a rare event, generally caused by invasion of the canal by paraspinal lesions or metastatically involved vertebral bodies. This case report reviews the clinical presentation, radiologic evaluation, and emergent therapy in two cases of spinal cord compromise involving patients with widely metastatic Wilms' tumor. One of these is the only known report of intradural metastasis in a child with this malignancy. Both cases illustrate the importance of anticipating and rapidly responding to neurologic complications that may arise in patients with aggressively metastatic Wilms' tumor.