CDK4 expression in chordoma: A potential therapeutic target.

Chordomas are rare bone tumors and treatment is commonly based on a combination of surgery and radiotherapy. There is no standard chemotherapy treatment for chordoma. The aim of this study was to determine the expression of cyclin-dependent kinase 4 (CDK4) in chordoma and its therapeutic implications. We evaluated CDK4 expression both in chordoma cell lines and in chordoma tissues. Also, we investigated the functional roles of CDK4 in chordoma cell growth and proliferation. Furthermore, the therapeutic implications of targeting CDK4 in chordoma were evaluated. We found CDK4 highly expressed in chordoma cell lines and in a majority (97.7%) of chordoma tissues. Higher CDK4 expression correlated with metastasis and recurrence of chordoma. Treatment of chordoma cells using CDK4 inhibitor palbociclib could efficiently inhibit chordoma cells growth and proliferation. These data demonstrate that targeting CDK4 may be useful as a novel strategy in the treatment of chordoma. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1581-1589, 2018.

Pharmacokinetics and tolerability of NSC23925b, a novel P-glycoprotein inhibitor: preclinical study in mice and rats.

Overexpression of P-glycoprotein (Pgp) increases multidrug resistance (MDR) in cancer, which greatly impedes satisfactory clinical treatment and outcomes of cancer patients. Due to unknown pharmacokinetics, the use of Pgp inhibitors to overcome MDR in the clinical setting remains elusive despite promising in vitro results. The purpose of our current preclinical study is to investigate the pharmacokinetics and tolerability of NSC23925b, a novel and potent P-glycoprotein inhibitor, in rodents. Plasma pharmacokinetic studies of single-dose NSC23925b alone or in combination with paclitaxel or doxorubicin were conducted in male BALB/c mice and Sprague-Dawley rats. Additionally, inhibition of human cytochrome P450 (CYP450) by NSC23925b was examined in vitro. Finally, the maximum tolerated dose (MTD) of NSC23925b was determined. NSC23925b displayed favorable pharmacokinetic profiles after intraperitoneal/intravenous (I.P./I.V.) injection alone or combined with chemotherapeutic drugs. The plasma pharmacokinetic characteristics of the chemotherapy drugs were not affected when co-administered with NSC23925b. All the animals tolerated the I.P./I.V. administration of NSC23925b. Moreover, the enzymatic activity of human CYP450 was not inhibited by NSC23925b. Our results demonstrated that Pgp inhibitor NSC23925b exhibits encouraging preclinical pharmacokinetic characteristics and limited toxicity in vivo. NSC23925b has the potential to treat cancer patients with MDR in the future.

Targeting EZH2-mediated methylation of H3K27 inhibits proliferation and migration of Synovial Sarcoma in vitro.

Synovial sarcoma is an aggressive soft tissue sarcoma genetically defined by the fusion oncogene SS18-SSX. It is hypothesized that either SS18-SSX disrupts SWI/SNF complex inhibition of the polycomb complex 2 (PRC2) methyltransferase Enhancer of Zeste Homologue 2 (EZH2), or that SS18-SSX is able to directly recruit PRC2 to aberrantly silence target genes. This is of potential therapeutic value as several EZH2 small molecule inhibitors are entering early phase clinical trials. In this study, we first confirmed EZH2 expression in the 76% of human synovial sarcoma samples. We subsequently investigated EZH2 as a therapeutic target in synovial sarcoma in vitro. Knockdown of EZH2 by shRNA or siRNA resulted in inhibition of cell growth and migration across a series of synovial sarcoma cell lines. The EZH2 selective small-molecule inhibitor EPZ005687 similarly suppressed cell proliferation and migration. These data support the hypothesis that targeting EZH2 may be a promising therapeutic strategy in the treatment of synovial sarcoma; clinical trials are initiating enrollment currently.

Evaluation of P-glycoprotein (Pgp) expression in human osteosarcoma by high-throughput tissue microarray.

Survival of osteosarcoma patients is currently limited by the development of metastases and multidrug resistance (MDR). A well-established cause of MDR involves overexpression of P-glycoprotein (Pgp) in tumor cells. However, some discrepancies still exist as to the clinical significance of Pgp in osteosarcoma. We sought to elucidate further whether the Pgp expression correlated with clinical behavior in a series of patients with osteosarcoma via high-throughput tissue microarray (TMA) analysis. Immunohistochemical analysis of Pgp expression in a TMA of 114 specimens with a retrospective review of 70 osteosarcoma patients admitted to the Massachusetts General Hospital (MGH) was performed. High Pgp expression was correlated with metastasis development and poor response to pre-operative chemotherapy in osteosarcoma patients. Eighteen of the fifty-seven patients initially admitted with primary osteosarcoma showed high Pgp expression. Among these 18 patients with high Pgp expression, 13 of 18 (72%) patients eventually developed metastases. There was no significant clinical relevance between Pgp expression and osteosarcoma survival. These results support that high expression of Pgp is important, but cannot be assigned as, an individual predictor in the development of human osteosarcoma. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1606-1612, 2016.

Rhabdomyosarcoma: Advances in Molecular and Cellular Biology.

Rhabdomyosarcoma (RMS) is the most common soft tissue malignancy in childhood and adolescence. The two major histological subtypes of RMS are alveolar RMS, driven by the fusion protein PAX3-FKHR or PAX7-FKHR, and embryonic RMS, which is usually genetically heterogeneous. The prognosis of RMS has improved in the past several decades due to multidisciplinary care. However, in recent years, the treatment of patients with metastatic or refractory RMS has reached a plateau. Thus, to improve the survival rate of RMS patients and their overall well-being, further understanding of the molecular and cellular biology of RMS and identification of novel therapeutic targets are imperative. In this review, we describe the most recent discoveries in the molecular and cellular biology of RMS, including alterations in oncogenic pathways, miRNA (miR), in vivo models, stem cells, and important signal transduction cascades implicated in the development and progression of RMS. Furthermore, we discuss novel potential targeted therapies that may improve the current treatment of RMS.

CD44 is a direct target of miR-199a-3p and contributes to aggressive progression in osteosarcoma.

Osteosarcoma is the most common primary bone malignancy in children and adolescents. Herein, we investigated the role of cluster of differentiation 44 (CD44), a cell-surface glycoprotein involved in cell-cell interactions, cell adhesion, and migration in osteosarcoma. We constructed a human osteosarcoma tissue microarray with 114 patient tumor specimens, including tumor tissues from primary, metastatic, and recurrent stages, and determined the expression of CD44 by immunohistochemistry. Results showed that CD44 was overexpressed in metastatic and recurrent osteosarcoma as compared with primary tumors. Higher expression of CD44 was found in both patients with shorter survival and patients who exhibited unfavorable response to chemotherapy before surgical resection. Additionally, the 3'-untranslated region of CD44 mRNA was the direct target of microRNA-199a-3p (miR-199a-3p). Overexpression of miR-199a-3p significantly inhibited CD44 expression in osteosarcoma cells. miR-199a-3p is one of the most dramatically decreased miRs in osteosarcoma cells and tumor tissues as compared with normal osteoblast cells. Transfection of miR-199a-3p significantly increased the drug sensitivity through down-regulation of CD44 in osteosarcoma cells. Taken together, these results suggest that the CD44-miR-199a-3p axis plays an important role in the development of metastasis, recurrence, and drug resistance of osteosarcoma. Developing strategies to target CD44 may improve the clinical outcome of osteosarcoma.

Up-regulation of CD44 in the development of metastasis, recurrence and drug resistance of ovarian cancer.

The clinical significance of Cluster of Differentiation 44 (CD44) remains controversial in human ovarian cancer. The aim of this study is to evaluate the clinical significance of CD44 expression by using a unique tissue microarray, and then to determine the biological functions of CD44 in ovarian cancer. In this study, a unique ovarian cancer tissue microarray (TMA) was constructed with paired primary, metastatic, and recurrent tumor tissues from 26 individual patients. CD44 expression in TMA was assessed by immunohistochemistry. Both the metastatic and recurrent ovarian cancer tissues expressed higher level of CD44 than the patient-matched primary tumor. A significant association has been shown between CD44 expression and both the disease free survival and overall survival. A strong increase of CD44 was found in the tumor recurrence of mouse model. Finally, when CD44 was knocked down, proliferation, migration/invasion activity, and spheroid formation were significantly suppressed, while drug sensitivity was enhanced. Thus, up-regulation of CD44 represents a crucial event in the development of metastasis, recurrence, and drug resistance to current treatments in ovarian cancer. Developing strategies to target CD44 may prevent metastasis, recurrence, and drug resistance in ovarian cancer.

MicroRNA-155 expression is independently predictive of outcome in chordoma.

BACKGROUND: Chordoma pathogenesis remains poorly understood. In this study, we aimed to evaluate the relationships between microRNA-155 (miR-155) expression and the clinicopathological features of chordoma patients, and to evaluate the functional role of miR-155 in chordoma. METHODS: The miRNA expression profiles were analyzed using miRNA microarray assays. Regulatory activity of miR-155 was assessed using bioinformatic tools. miR-155 expression levels were validated by reverse transcription-polymerase chain reaction. The relationships between miR-155 expression and the clinicopathological features of chordoma patients were analyzed. Proliferative, migratory and invasive activities were assessed by MTT, wound healing, and Matrigel invasion assays, respectively. RESULTS: The miRNA microarray assay revealed miR-155 to be highly expressed and biologically active in chordoma. miR-155 expression in chordoma tissues was significantly elevated, and this expression correlated significantly with disease stage (p = 0.036) and the presence of metastasis (p = 0.035). miR-155 expression also correlated significantly with poor outcomes for chordoma patients (hazard ratio, 5.32; p = 0.045). Inhibition of miR-155 expression suppressed proliferation, and the migratory and invasive activities of chordoma cells. CONCLUSIONS: We have shown miR-155 expression to independently affect prognosis in chordoma. These results collectively indicate that miR-155 expression may serve not only as a prognostic marker, but also as a potential therapeutic target in chordoma.

Targeting CDK11 in osteosarcoma cells using the CRISPR-Cas9 system.

Osteosarcoma is the most common type primary malignant tumor of bone. Patients with regional osteosarcoma are routinely treated with surgery and chemotherapy. In addition, many patients with metastatic or recurrent osteosarcoma show poor prognosis with current chemotherapy agents. Therefore, it is important to improve the general condition and the overall survival rate of patients with osteosarcoma by identifying novel therapeutic strategies. Recent studies have revealed that CDK11 is essential in osteosarcoma cell growth and survival by inhibiting CDK11 mRNA expression with RNAi. Here, we apply the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 system, a robust and highly efficient novel genome editing tool, to determine the effect of targeting endogenous CDK11 gene at the DNA level in osteosarcoma cell lines. We show that CDK11 can be efficiently silenced by CRISPR-Cas9. Inhibition of CDK11 is associated with decreased cell proliferation and viability, and induces cell death in osteosarcoma cell lines KHOS and U-2OS. Furthermore, the migration and invasion activities are also markedly reduced by CDK11 knockout. These results demonstrate that CRISPR-Cas9 system is a useful tool for the modification of endogenous CDK11 gene expression, and CRISPR-Cas9 targeted CDK11 knockout may be a promising therapeutic regimen for the treatment of osteosarcoma.

MicroRNA-1 (miR-1) inhibits chordoma cell migration and invasion by targeting slug.

Recent studies have revealed that expression of miRNA-1 (miR-1) is frequently down-regulated in several cancer types including chordoma. Identifying and validating novel targets of miR-1 is useful for understanding the roles of miR-1 in chordoma. We aimed to further investigate the functions of miR-1 in chordoma. Specifically, we assessed whether restoration of miR-1 affects cell migration and invasion in chordoma, and focused on the miR-1 potential target Slug gene. Migratory and invasive activities were assessed by wound healing and Matrigel invasion assays, respectively. Cell proliferation was determined by MTT assay. Slug expression was evaluated by Western blot, immunofluorescence, and immunohistochemistry. Restoration of miR-1 expression suppressed the migratory and invasive activities of chordoma cells. Transfection of miR-1 inhibited cell proliferation both time- and dose-dependently in chordoma. MiR-1 transfected cells showed inhibited Slug expression. Slug was over-expressed in chordoma cell lines and advanced chordoma tissues. In conclusion, we have shown that miR-1 directly targets the Slug gene in chordoma. Restoration of miR-1 suppressed not only proliferation, but also migratory and invasive activities, and reduced the Slug expression in chordoma cells. These results collectively indicate that miR-1/Slug pathway is a potential therapeutic target because of its crucial roles in chordoma cell growth and migration.

Malignant lymphoma of bone: a review of 119 patients.

BACKGROUND: Lymphoma of bone is uncommon. As a result of this, many aspects of primary lymphoma of bone (PLB) are controversial: the definition, treatment strategies, response criteria, and prognostic factors. QUESTIONS/PURPOSES: We sought to determine the following in an analysis from a single center over a four-decade period: (1) 5-year disease-free survival of patients with PLB as well as those with systemic lymphoma with bone involvement; and (2) whether prognostic factors (sex, site of tumor, age) were associated with 5-year survival. METHODS: A total of 119 patients with lymphoma involving the musculoskeletal system were retrospectively evaluated. Among these, 94 patients who had a minimum followup of 6 months (mean, 67 months; range, 6 months to 34 years) were further analyzed for the skeletal site of involvement, the orthopaedic intervention(s) needed, and survival. The overall median age was 45 years (range, 7-87 years). The female-to-male ratio was 1:1.53. There were 70 (65 unifocal, five multifocal) patients with PLB. The femur was the most frequent site involved. Appendicular skeleton involvement was substantially higher in patients with PLB. Thirty-four (36%) patients had at least one surgical intervention. Fourteen patients (41%) needed more than one major surgical intervention. RESULTS: The disease-free 5-year survival for patients with PLB was 81% and for the patients with systemic lymphoma with bone involvement, it was 44%. The disease-free 5-year survival of the patients with PLB younger than 60 years old and 60 years old or older was 90% and 62%, respectively. Age was the only prognostic factor on survival of patients with PLB. CONCLUSIONS: Orthopaedic intervention was usually needed for pathologic fractures, avascular necrosis, spinal cord compression, or for the lesions of the weightbearing bones compromising stability or joint motion. The potential for long-term survival suggests the use of implants and techniques that have the best chance of long-term success.

Giant cell tumor of bone.

Giant cell tumor (GCT) of bone is one type of giant cell-rich lesion of bone. This benign mesenchymal tumor has characteristic multinuclear giant cells. Mononuclear stromal cells are the physiologically active and diagnostic cell type. Most GCTs are located in the epiphyseal regions of long bones. The axial skeleton-primarily the sacrum-is a secondary site of involvement. Most patients present with pain, swelling, joint effusion, and disability in the third and fourth decades of life. Imaging studies are important for tumor staging and radiographic grading. Typically, these clinically active but slow-growing tumors are confined to bone, with relatively well-defined radiographic borders. Monostotic disease is most common. Metastatic spread to the lungs is rare. Extended intralesional curettage with or without adjuvant therapy is the primary treatment choice. Local recurrence is seen in ≤ 20% of cases, and a second local intralesional procedure is typically sufficient in cases that are detected early. Medical therapies include diphosphonates and denosumab. Denosumab has been approved for use in osteoporosis as well as breast and prostate cancer metastatic to bone. Medical therapy and radiotherapy can alter the management of GCT of bone, especially in multifocal disease, local recurrences, and bulky central/axial disease.

Establishment and characterization of a novel chordoma cell line: CH22.

Chordoma is a rare primary malignant bone tumor and there exist only a few established human chordoma cell lines. The scarcity of robust chordoma cell lines has limited the ability to study this tumor. In this report, we describe the establishment of a novel chordoma cell line and characterize its in vitro and in vivo behaviors. The tumor tissue was isolated from a patient with recurrent chordoma of the sacrum. After 6 months in culture, the chordoma cell line, referred here as CH22, was established. Microscopic analysis of two-dimensional culture confirmed that the CH22 cells exhibited a typical vacuolated cytoplasm similar to the well-established chordoma cell line U-CH1. Electron microscopy showed cohesive cells with numerous surface filopodia, pockets of glycogen and aggregates of intermediate tonofilaments in cytoplasm. Three-dimensional culture revealed that the CH22 cells could grow and form clusters by day 8. The MTT assays demonstrated that, compared with sensitive osteosarcoma cell lines, CH22 cells were relatively resistant to conventional chemotherapeutic drugs. Western blotting and immunofluorescence analysis confirmed that the CH22 cells expressed brachyury, vimentin, and cytokeratin. Finally, histological analysis of CH22 xenograft tumor tissues demonstrated the appearance of physaliphorous cells and positive staining of brachyury, cytokeratin, and S100. By CT and MRI, imaging xenografts showed the typical appearances seen in human chordomas. These findings suggest that the established novel human chordoma cell line CH22 and its tumorigenecity in SCID nude mice may serve as an important model for studying chordoma cell biology and the development of new therapeutic modalities.

Chondrosarcoma of the mobile spine: a review of 21 cases treated at a single center.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To determine the effect of modern surgical and aggressive radiation techniques on outcome in patients with spinal chondrosarcoma. SUMMARY OF BACKGROUND DATA: Chondrosarcoma of the spine presents a difficult surgical challenge. Surgical excision is considered the standard of care, yet complete excision is not always feasible, and rates of local control and survival are inferior to those reported for the extremities. METHODS: We performed a retrospective review of cases of chondrosarcoma involving the spine above the sacrum treated surgically at our institution between 1984 and 2006. Medical charts, radiology reports, pathology reports, and operative notes were reviewed for all patients. Available imaging studies were also reviewed. The Student t test and Fisher exact test were used to compare baseline differences between groups. Survivorship analysis was performed using Kaplan-Meier methodology. Overall survival was calculated on the basis of en bloc resection, margins, local recurrence, and metastasis. RESULTS: Twenty-one patients were treated surgically for chondrosarcoma of the mobile spine. Twenty of the 21 patients were also treated with radiation with a mean dose of 71 Gy (range, 53-83). The average overall survival for all patients in our series was 120.5 months (SE = 32.9; range, 8.5-298.9 months). The 1- and 5-year survival rates for all patients were 90% and 61%, respectively. Patients treated with en bloc resection had a better overall survival (198 months: SE = 24.5; range, 24-224.7 months) than those who underwent intralesional excision (77 months: SE = 27.3; range, 8.5-298.9 months) (P = 0.05). Five (24%) patients developed local recurrence and 9 (43%) developed metastasis. All recurrences occurred in patients who underwent intralesional resection. Metastasis, high-grade tumor, and positive surgical margins were associated with worse overall survival (P < 0.001, 0.02, and 0.04, respectively). CONCLUSION: In this series, en bloc resection, the absence of metastasis, low-grade tumors, and negative margins were associated with improved overall survival. The aggressive use of sophisticated surgical and radiation techniques appears to confer an advantage to patients, decreasing local recurrence and increasing overall survival, even following incomplete surgical resection.

Hand and foot abnormalities associated with genetic diseases.

INTRODUCTION: The small bones and soft tissues of the hands and feet can be affected by systemic disorders, and frequently, the findings are quite unique and virtually diagnostic for some genetic or metabolic disorders. MATERIALS AND METHODS: Photographs and imaging studies for the hands and feet are available in a digitized system, which has been approved by our hospital institutional review board. Examination of these and their description can establish a relationship with some degree of certainty to a series of highly variable and uncommon clinical disorders. RESULTS: Description of the clinical, physiologic and genetic characteristics, and illustrations of hand and foot abnormalities are provided for an array of diseases, including Ellis-van Creveld syndrome, fibrodysplasia ossificans progressiva, achondroplasia, Kniest dysplasia, pseudo- and pseudo-pseudohypoparathyroidism, acromegaly, nail-patella syndrome, Marfan's disease, cartilage-hair hypoplasia, and several forms of mucopolysaccharidosis. CONCLUSIONS: The findings support the concept that many genetic disorders can often be diagnosed by clinical and imaging examination of the patient's hands and feet.

Osteosarcoma of the spine: experience in 26 patients treated at the Massachusetts General Hospital.

BACKGROUND CONTEXT: Because of the low incidence, treatment recommendations for spinal osteosarcoma are guided by the results of small series and case reports. Many include patients who presented for treatment over the course of three to four decades. PURPOSE: The goal of this investigation was to report the treatments, results, and overall survivorship of 26 patients treated for osteosarcoma of the spine at a single institution. STUDY DESIGN: Retrospective prognostic series (Level III evidence). PATIENT SAMPLE: Twenty-six patients treated at a single center for osteosarcoma of the spine over a 26-year period. OUTCOME MEASURES: Estimation of patient survival, local recurrence, and the presence of metastatic disease. METHODS: We performed a retrospective review of cases of osteosarcoma involving the spine treated at our institution between 1982 and 2008. Medical charts, radiology reports, pathology reports, and operative notes were reviewed for all patients. Available imaging studies were also reviewed. The log-rank test was used to compare baseline differences between groups. Survivorship analysis was performed using Kaplan-Meier methodology. The effect of Paget osteosarcoma, type of resection, presence of local recurrence, tumor size, surgical margins, and metastases on overall survival were also investigated using the log-rank test. RESULTS: Twenty-six patients were included for review in this study. Twenty individuals were treated surgically, and 24 were treated with radiation with a mean dose of 62.2 Gy (range 20-84.7 Gy). Twenty-five patients received chemotherapy. Of those treated surgically, seven received en bloc resection. The median overall survival for all patients in our series was 29.5 months (standard error 14.7, 95% confidence interval 0.6-58). Local recurrence developed in 7 patients (27%), and metastasis occurred in 16 individuals (62%). Patients with Paget osteosarcoma had worse overall survival (p<.001). CONCLUSIONS: Results presented here confirm a poor prognosis for patients with spinal osteosarcoma. Although combination therapies, including surgery, chemotherapy, and high-dose radiation, achieve adequate short-term survival, the 5-year mortality rate remains high.

Oleanane triterpenoid CDDO-Me induces apoptosis in multidrug resistant osteosarcoma cells through inhibition of Stat3 pathway.

BACKGROUND: The activation of signal transducer and activator of transcription 3 (Stat3) pathway correlates with tumor growth, survival, drug resistance and poor prognosis in osteosarcoma. To explore the potential therapeutic values of this pathway, we assessed both the expression and the activation of Stat3 pathway in several pairs of multidrug resistant (MDR) osteosarcoma cell lines, and tissues. To explore the potential therapeutic values of this pathway, we analyzed the ability of the synthetic oleanane triterpenoid, C-28 methyl ester of 2-cyano-3,12-dioxoolen-1,9-dien-28-oic acid (CDDO-Me), to inhibit Stat3 expression and activation as well as its effects on doxorubicin sensitivity in osteosarcoma cells. METHODS: Expression of Stat3, phosphorylated Stat3 (pStat3) and Stat3 targeted proteins, including Bcl-XL, Survivin and MCL-1 were determined in drug sensitive and MDR osteosarcoma cell lines and tissues by Western blot analysis. The effect of CDDO-Me on osteosarcoma cell growth was evaluated by MTT and apoptosis by PARP cleavage assay and caspase-3/7 activity. RESULTS: Stat3 pathway was activated in osteosarcoma tissues and in MDR cell lines. CDDO-Me inhibited growth and induced apoptosis in osteosarcoma cell lines. Treatment with CDDO-Me significantly decreased the level of nuclear translocation and phosphorylation of Stat3. The inhibition of Stat3 pathway correlated with the suppression of the anti-apoptotic Stat3 targeted genes Bcl-XL, survivin, and MCL-1. Furthermore, CDDO-Me increased the cytotoxic effects of doxorubicin in the MDR osteosarcoma cell lines. CONCLUSIONS: Stat3 pathway is overexpressed in MDR osteosarcoma cells. CDDO-Me significantly inhibited Stat3 phosphorylation, Stat3 nuclear translocation and induced apoptosis in osteosarcoma. This study provides the framework for the clinical evaluation of CDDO-Me, either as monotherapy or perhaps even more effectively in combination with doxorubicin to treat osteosarcoma and overcome drug resistance.