[The current situation of occupational burnout and its influencing factors among orphan child care workers in Nanjing]

Objective: To explore the status of job burnout of nurses for orphans and disabled children in Nanjing and its influencing factors, so as to provide reference for promoting the mental health of nurses for orphans and disabled children. Methods: From February to May, 2017, a cross-sectional survey was conducted among 236 nurses working in social welfare institutions for orphans and disabled children in Nanjing, using Occupational Stress Indicator (OSI) and Maslach Burnout Inventory (MBI) . It investigated the status of job burnout among nurses of orphans and disabled children, logistic regression analysis was used to explore the effect of occupational stress on the incidence of job burnout of nurses for orphans and disabled children. Results: The results showed that the incidence of job burnout was 67.37% (159/236) , the incidence of job burnout was negatively correlated with behavioral characteristics and family support, the incidence of emotional exhaustion was positively correlated with task control and job monotony (P<0.05) , and negatively correlated with role ambiguity and job satisfaction (P<0.05) . The incidence of depersonalization was negatively correlated with job monotony and peer support (P<0.05) . Conclusion: The nurses of orphans and disabled children have serious job burnout. Occupational stress factors, personality characteristics and relieving factors have influence on the incidence of job burnout.

[Study on occupational stress response of orphans and disabled children care workers in Nanjing]

Objective: To explore the status quo of occupational stress and its influencing factors of nursing staff for orphaned and disabled children in Nanjing, and to put forward measures for adverse reactions to occupational stress, so as to ensure the psychological health of this occupational population. Methods: From February to May 2017, 236 nursing assistants for orphans and disabled children in Nanjing social welfare home were selected by cluster sampling method. The occupational stress index(occupational stress indictor, OSI) was used to investigate occupational stress response and occupational stress factors. Partial correlation and multiple linear regression were used for statistical analysis. Results: The scores of job satisfaction, mental health and depressive symptoms in occupational stress reaction were (43. 99±6. 83) , (36. 09±4. 59) and (17. 31±2. 44) re- spectively. In terms of job satisfaction, work monotony, logic and compound change were the contributing fac- tors (P<0. 05) , task strategy and task control were negative factors (P<0. 05) ; on mental health, opportunities were raised and participation in decision-making Self-esteem, technology utilization, environmental control, time management, task strategy and support of colleagues as contributing factors (P<0. 05) , ambition and role conflicts as negative factors (P<0. 05) ; on depression, work input, participation Decision-making, promotion opportunities and behavioral characteristics were protective factors (P<0. 05 ) . Conclusion: Occupational stress among caregivers of orphans and disabled children cannot be ignored. Occupational stress reaction is serious. Occupational stress factors should be reduced and individual stress coping ability should be enhanced.

[Analysis of occupational stress and occupational exhaustion of primary caregivers]

Objective: To investigate the occupation stress and job burnout of orphan child care workers in Nanjing and nursing staff in Yangzhong primary hospital, to compare the differences of occupational stress and job burnout between the two social service workers. Methods: From February to May 2017, a cross- sectional survey was conducted. Cluster sampling method was used to investigate the occupation stress and job burnout of orphan child care workers in Nanjing and nursing staff in Yangzhong primary hospital, totally 403 people, by a combination of the Internet of things assessment system of occupational stress and traditional questionnaire. Results: There were statistically significant differences of occupational stress and job burnout scores of both social service workers (P<0.05). Orphan child care workers in job control, technology utilization, job routinization, work risk, role ambiguity and participation decision-making, anxiety state, body complain, life attitude, behavior characteristics, ambition, anxiety trait, social support, logic, family-work relationship and depersonalization were higher than those of Yangzhong primary nurses (P<0.05); Primary nurses in Yangzhong in quantitative load and change, workload, role conflict, job prospects, promotion, depressive symptom, daily stress, self-esteem, task strategy, time management, work input, and personal accomplishment reduction scored higher than those of Orphan child care workers (P<0.05). The logistic regression analysis of the occupational depletion positive rate of the two social service personnel showed that the protective factors of the nursing staff of the orphans and disabled children had behavioral characteristics and family support(OR=0.877, P=0.044; OR=0.691, P=0.001) . The contributing factors of the primary nursing staff in Yangzhong were task control, workload, work psychological control source (OR=1.110, P=0.019; OR=1.128, P<0.001;OR=1.066, P=0.032) . The protection factors were technical utilization, opportunities for improvement, and mental health (OR=0.775, P=0.005; OR=0.765, P=0.006; OR=0.914, P=0.002) . Conclusion: The work content, the service object and the nature of the unit of primary caregivers influence the state of occupational stress and job burnout. The influencing factors of occupational stress and job burnout are not identical, Different social service personnel show occupational stress and occupational exhaustion in different aspects, and it is necessary to propose mitigation measures for two kinds of social service personnel.

[The influence of demographic characteristics on occupational stress of orphan child care workers]

Objective: To investigate the occupation stress of orphan child care workers in Nanjing, to explore the influence of different demographic characteristics on occupational stress of orphan child care workers and propose measures. Methods: Cluster sampling method was used to investigate the occupation stress of 236 people of orphan child care workers in Nanjing by a combination of the Internet of things assessment system of occupational stress and traditional questionnaire. Results: The scores of workload, job prospects, participation decision-making, anxiety and logical in different age groups among orphan child care workers were statistically different (P<0.05) ; The scores of organizational loyalty in different education groups among orphan child care workers were statistically different (P<0.05) ; The scores of task control, resource control, workload, job prospects, job satisfaction, mental health, anxiety and ambition were statistically different among orphan child care workers with different job titles (P<0.05) ; The scores of role conflict, role ambiguity, job satisfaction, mental health, anxiety, self-esteem, colleague support, family support and task strategy were statistically different orphan child care workers in different classes (P<0.05) . Conclusion: Different demographic characteristics will have certain influence on occupational stress of orphan child care workers.

CdS nanoparticles of different lengths induce differential responses in some of the liver functions of mice

Cadmium sulfide nanoparticles (CdS NPs) are one of important nanoparticle materials which are widely used in photoelectric production, but their potential health hazard to the liver is not clear. This study is aimed at exploring the possible mechanisms of liver injury induced by CdS NPs. Male mice were treated with nanoparticles of 110-130 nm and 80-100 nm cadmium sulfide. The main methods were based on detecting the vigor of superoxide dismutase (SOD) and glutathione (GSH), and content of malondialdehyde (MDA) in both blood and liver tissues as well as on observing the pathological changes in liver tissue. CdS NPs suppressed the activity of SOD and GSH, and increased the serum MDA content (p < 0.05); both effects were observed together in liver tissues of 80-100 nm group (p < 0.05) and were accompanied by an obviously inflammatory response. CdS NPs induced oxidative damage and inflammatory response in liver tissue, which may be an underlying mechanism for its pulmonary toxicity. Additionally, the toxicity of CdS NPs was closely related to the size of nanoparticles. Pathological results showed that the hepatotoxicity of shorter CdS NPs is greater than that of longer CdS NPs (Tab. 6, Fig. 3, Ref. 20).

[Impacts of EGFR 19 exon mutations on brain metastases in treatment-naïve patients with lung adenocarcinoma]

Objective: To investigate the relationship between the status of epidermal growth factor receptor (EGFR) mutations and brain metastases in patients with lung adenocarcinoma. Methods: From August 2010 to May 2015, a total of 1 063 lung adenocarcinoma patients with identified status of EGFR mutations in Shanxi Cancer Hospital were enrolled, of which 456 patients had EGFR mutations. Multivariate Logistic regression model was used to analyze the correlation between EGFR mutation status and brain metastases in patients with lung adenocarcinoma. Results: In 125 patients with brain metastases before initial treatment, 65 patients had EGFR mutations, including 36 patients with deletion mutations in exon 19. The frequency of EGFR 19 exon mutation was 28.8% (36/125). Among 456 patients with EGFR mutations, 65(14.3%) patients were with brain metastases, in which 36(55.0%) had deletion mutations in exon 19. The multivariate analysis showed that age, Eastern Cooperative Oncology Group (ECOG) score, EGFR mutations and N staging were associated with brain metastases(P<0.05). Further subgroup multivariate analyses showed that age, ECOG score, mutation status in exon 19 and N staging were associated with brain metastases (P<0.05). Conclusions: EGFR mutation status is related to brain metastases. Mutations in EGFR exon 19 is an independent risk factor for brain metastases.

Targeting Lyn inhibits tumor growth and metastasis in Ewing's sarcoma

Src family tyrosine kinases (SFK) play an important role in growth and metastasis of many types of human malignancies. However, their significance in Ewing's sarcoma remains to be elucidated. The purpose of this study was to evaluate the role of Lyn, one member of the SFK, in Ewing's sarcoma growth and metastasis and to determine whether a SFK inhibitor can induce Ewing's tumor regression. Lyn was expressed and activated in TC71, A4573, and SK-ES human Ewing's sarcoma cells. Lyn expression was seen in 13 of 15 patient tumor samples, 6 of which showed Lyn activation. Specific inhibition of Lyn using small interfering RNA significantly decreased primary tumor growth and lytic activity, and also reduced lung metastases in vivo. Down-regulation of Lyn resulted in decreased invasive capacity of tumor cells in vitro. AP23994, a small-molecule SFK inhibitor, decreased Lyn kinase activity and suppressed TC71 cell growth in vitro in a dose-dependent manner. Furthermore, treatment of mice bearing s.c. TC71 tumors with AP23994 or with polyethylenimine/Lyn-small interfering RNA gene therapy resulted in reduced Lyn kinase activity and significant tumor growth suppression. EWS/FLI-1, which is translocation fusion protein associated with Ewing's sarcoma, regulated Lyn gene expression and kinase activity. These data suggest that targeting Lyn may be a new therapeutic approach in treatment of Ewing's sarcoma.

Bone marrow subsets differentiate into endothelial cells and pericytes contributing to Ewing's tumor vessels

Hematopoietic progenitor cells arising from bone marrow (BM) are known to contribute to the formation and expansion of tumor vasculature. However, whether different subsets of these cells have different roles in this process is unclear. To investigate the roles of BM-derived progenitor cell subpopulations in the formation of tumor vasculature in a Ewing's sarcoma model, we used a functional assay based on endothelial cell and pericyte differentiation in vivo. Fluorescence-activated cell sorting of human cord blood/BM or mouse BM from green fluorescent protein transgenic mice was used to isolate human CD34+/CD38(-), CD34+/CD45+, and CD34(-)/CD45+ cells and mouse Sca1+/Gr1+, Sca1(-)/Gr1+, VEGFR1+, and VEGFR2+ cells. Each of these progenitor subpopulations was separately injected intravenously into nude mice bearing Ewing's sarcoma tumors. Tumors were resected 1 week later and analyzed using immunohistochemistry and confocal microscopy for the presence of migrated progenitor cells expressing endothelial, pericyte, or inflammatory cell surface markers. We showed two distinct patterns of stem cell infiltration. Human CD34+/CD45+ and CD34+/CD38(-) and murine VEGFR2+ and Sca1+/Gr1+ cells migrated to Ewing's tumors, colocalized with the tumor vascular network, and differentiated into cells expressing either endothelial markers (mouse CD31 or human vascular endothelial cadherin) or the pericyte markers desmin and alpha-smooth muscle actin. By contrast, human CD34(-)/CD45+ and mouse Sca1(-)/Gr1+ cells migrated predominantly to sites outside of the tumor vasculature and differentiated into monocytes/macrophages expressing F4/80 or CD14. Our data indicate that only specific BM stem/progenitor subpopulations participate in Ewing's sarcoma tumor vasculogenesis.

Stromal cell-derived factor-1 stimulates vasculogenesis and enhances Ewing's sarcoma tumor growth in the absence of vascular endothelial growth factor

Stromal cell-derived Factor-1alpha (SDF-1alpha) stimulates the migration of bone marrow (BM) cells, similar to vascular endothelial growth factor (VEGF). We previously demonstrated that inhibition of VEGF(165) by small interfering RNA inhibited Ewing's sarcoma tumor growth, tumor vessel formation and recruitment of BM cells to the tumor. To determine the importance of BM cells in tumor vessel development, we investigated the effects of SDF-1alpha on VEGF-inhibited TC/siVEGF(7-1) Ewing's tumor neovasculature formation and growth. The effect of SDF-1alpha on CD34(+) progenitor cell chemotaxis was determined in vivo. Using a BM transplantation model with GFP(+) transgenic mice as BM donors and nude mice as recipients, we evaluated the effect of SDF-1alpha on the recruitment of BM-derived cells to VEGF(165)-inhibited TC/siVEGF(7-1) tumors, as well as its effect on neovasculature development, vessel morphology and tumor growth. SDF-1alpha stimulated the migration of CD34(+) progenitor cells to Matrigel plugs in vivo and promoted the retainment of BM-derived pericytes in close association with perfused, functional tumor vessels. Intratumor inoculation of Ad-SDF-1alpha into TC/siVEGF(7-1) tumors resulted in increased SDF-1 and PDGF-BB expression, augmented tumor growth, an increase in the number of large, lumen-bearing vascular structures, and enhanced vessel pericyte coverage, with no change in VEGF(165). SDF-1alpha stimulates BM cell chemotaxis and the association of these cells with functional tumor vessels. Furthermore, SDF-1alpha enhances tumor neovascularization and growth with no alteration in VEGF(165). Our work suggests that SDF-1-mediated vasculogenesis may represent an alternate pathway that could potentially be utilized by tumors to sustain growth and neovasculature expansion after anti-VEGF therapy.

The osterix transcription factor down-regulates interleukin-1 alpha expression in mouse osteosarcoma cells

K7M2 mouse osteosarcoma cells form lytic tumors and are deficient in osterix (Osx), a zinc finger-containing transcription factor required for osteoblast differentiation and bone formation. Our previous studies showed that replacement of Osx suppresses lytic bone destruction. Cytokines, including interleukin (IL)-1alpha, IL-6, IL-11, and prostaglandin E2, have been shown to stimulate osteoclast activity. We showed that IL-1alpha production by K7M2 cells was significantly suppressed following Osx transfection through a transcription-mediated mechanism. Osx had no effect on IL-6, IL-11, or prostaglandin E2. Site-directed mutagenesis and chromatin immunoprecipitation indicated that Osx down-regulated IL-1alpha through an Sp1-binding site on the IL-1alpha promoter. Inhibiting Osx by small interfering RNA in two cell lines (Dunn and DLM8) that expressed high levels of Osx led to enhanced IL-1alpha promoter activity and protein production and altered the phenotype from blastic to lytic. These data suggest that Osx down-regulates IL-1alpha expression in mouse osteosarcoma cells via transcriptional repression of IL-1alpha and this may in turn affect the lytic activity of the tumor cells.

VEGF165 expression in the tumor microenvironment influences the differentiation of bone marrow-derived pericytes that contribute to the Ewing's sarcoma vasculature

We previously demonstrated that bone marrow (BM) cells migrate to Ewing's tumors and differentiate into endothelial cells within the tumor vasculature. Recent evidence suggests that the roles of BM cells in tumors are more diverse. We investigated whether non-endothelial cell types critical for tumor vessel development are also derived from migrated BM cells. We utilized BM transplantation with GFP(+) transgenic mice as BM donors and nude mice as recipients to track the fate of migrated BM cells. After engraftment, we injected recipient mice either subcutaneously or intramuscularly with Ewing's sarcoma cells. We labeled functional tumor vessels using intravascular perfusion staining with tomato lectin. We assessed BM cell recruitment/differentiation within the tumor microenvironment using immunohistochemistry. Ewing's tumors contained BM-derived cells that had differentiated into endothelial cells lining perfused tumor vessels. A substantial fraction of recruited BM cells also resided in the vessel vicinity and expressed desmin and PDGFR-beta, indicating smooth muscle cell differentiation. In order to further characterize the role of stem/progenitor cells in Ewing's sarcoma, we sorted Tie2(-) BM cells from Tie2-GFP transgenic mice and then injected them intravenously into Ewing's tumor-bearing mice. Tie2(-) BM progenitors migrated to Ewing's tumors and differentiated into Tie2(+) cells occupying a perivascular residence and expressing alpha-smooth muscle actin, desmin and PDGFR-beta, as well as VEGFR-2. We did not observe differentiation of Tie2(-) cells into Tie2(+) perivascular cells in VEGF(165)-inhibited TC/siVEGF(7-1) tumors. The differentiation of Tie2(-) BM cells into Tie2(+) cells in parental but not VEGF(165)-inhibited tumors indicates that the tumor microenvironment may influence the differentiation pathway.

VEGF165 is necessary to the metastatic potential of Fas(-) osteosarcoma cells but will not rescue the Fas(+) cells

Our previous studies showed that Fas expression correlates inversely with the metastatic potential of osteosarcoma (OS) cells and that the manipulation of Fas expression alters the lung metastatic phenotype. However, the role of VEGF in the growth and metastases of OS is unclear. The purpose of this study was to determine whether altering VEGF expression affects lung metastatic potential. LM7 metastatic OS cells were transfected with a small interfering RNA targeting human VEGF165 (LM7/siVEGF165) or a pcDNA4 plasmid expressing human VEGF165 (LM7/VEGF). We confirmed that VEGF165 expression was decreased in LM7/siVEGF165 cells and was increased in LM7/VEGF clones compared with control transfected clones. Fas expression was not altered in these transfected clones. We also transfected LM7 cells with Fas (LM7/Fas) or Fas together with VEGF165 (LM7/Fas/VEGF) to determine whether the overexpression of VEGF165 could enhance the metastatic potential of LM7 OS cells with high Fas expression (Fas(+)). LM7/siVEGF165 and LM7/Fas cells showed decreased lung metastatic potential. In addition, the overexpression of VEGF had no effect on the ability of LM7/Fas cells to form lung metastases. We therefore concluded that VEGF165 is critical to lung metastatic potential but is not sufficient to allow Fas(+) OS cells to survive in the Fas ligand lung microenvironment.

Corruption of the Fas pathway delays the pulmonary clearance of murine osteosarcoma cells, enhances their metastatic potential, and reduces the effect of aerosol gemcitabine

PURPOSE

Pulmonary metastases continue to be a significant problem in osteosarcoma. Apoptosis dysfunction is known to influence tumor development. Fas (CD95, APO-1)/FasL is one of the most extensively studied apoptotic pathways. Because FasL is constitutively expressed in the lung, cells that express Fas should be eliminated by lung endothelium. Cells with low or no cell surface Fas expression may be able to evade this innate defense mechanism. The purpose of these studies was to evaluate Fas expression in osteosarcoma lung metastases and the effect of gemcitabine on Fas expression and tumor growth.

EXPERIMENTAL DESIGN AND RESULTS

Using the K7M2 murine osteosarcoma model, Fas expression was quantified using immunohistochemistry. High levels of Fas were present in primary tumors, but no Fas expression was present in actively growing lung metastases. Blocking the Fas pathway using Fas-associated death domain dominant-negative delayed tumor cell clearance from the lung and increased metastatic potential. Treatment of mice with aerosol gemcitabine resulted in increased Fas expression and subsequent tumor regression.

CONCLUSIONS

We conclude that corruption of the Fas pathway is critical to the ability of osteosarcoma cells to grow in the lung. Agents such as gemcitabine that up-regulate cell surface Fas expression may therefore be effective in treating osteosarcoma lung metastases. These data also suggest that an additional mechanism by which gemcitabine induces regression of osteosarcoma lung metastases is mediated by enhancing the sensitivity of the tumor cells to the constitutive FasL in the lung.

Intranasal interleukin-12 gene therapy enhanced the activity of ifosfamide against osteosarcoma lung metastases

BACKGROUND

Cyclophosphamide (CTX) and ifosfamide (IFX) are alkylating agents used to treat osteosarcoma (OS). It was previously demonstrated that the sensitivity of OS cells to 4-hydroperoxycyclophosphamide (4-HC, the active metabolite of CTX) is augmented by interleukin (IL)-12 in vitro through a mechanism involving the Fas/FasL pathway. The purpose of these studies was to determine whether this synergistic effect is operational in vivo.

METHODS

Mice were injected intravenously with human LM7 osteosarcoma cells. Treatment was initiated with IFX (2.5 mg/kg intraperitoneally) with or without intranasal polyethylenimine (PEI):IL-12 gene therapy given twice weekly for 6 weeks.

RESULTS

Expression of IL-12 protein in the lung was demonstrated in all mice receiving intranasal PEI:IL-12 but not in control mice or those treated with IFX alone. Increased expression of FasL was detected in lungs of all mice receiving IFX. Both IFX and PEI:IL-12 alone significantly inhibited lung metastasis when compared with control groups (P < 0.05). However, the most significant tumor effect was observed in mice receiving IFX+PEI:IL-12 (P < 0.01). Immunohistochemical staining for CD31 and basic fibroblast growth factor (bFGF) and the number of proliferating cells as quantified by proliferating cell nuclear antigen (PCNA) staining were also most significantly decreased in mice receiving combination therapy.

CONCLUSIONS

These data indicate that combining IFX and IL-12 may have therapeutic potential and that this increased efficacy may be mediated through a mechanism involving the Fas/FasL pathway.

Association of alphavbeta3 integrin expression with the metastatic potential and migratory and chemotactic ability of human osteosarcoma cells

INTRODUCTION

Expression of adhesion molecules such as alphavbeta3 integrin has been associated with the metastatic potential of tumor cells. The purpose of this study was to determine whether alphavbeta3 expression correlated with the metastatic potential of human osteosarcoma cells.

MATERIALS AND METHODS

We developed a series of sublines (LM2-LM7) from human osteosarcoma SAOS parental cells, with progressively increasing potential to form lung metastases in nude mice after intravenous injection. SAOS parental and LM2 cells were poorly metastatic, but LM7 cells resulted in visible metastatic lung nodules by 6-8 weeks. We quantified alphavbeta3 integrin expression using flow cytometry.

RESULTS

alphavbeta3 expression correlated with the metastatic potential of the cells, with LM7 cells showing the highest expression. LM7 cell adhesion to vitronectin decreased after treatment with echistatin, a RGD-containing peptide antagonist of alphavbeta3. LM7 cells demonstrated higher chemotactic activity than SAOS cells to a homogenate made from lung tissue. This chemotactic activity was also inhibited by echistatin. These data indicated that alphavbeta3 was critical for the migration of LM7 cells to the lung homogenate. Chemotaxis to a liver homogenate was the same for LM7 and SAOS cells. Migration of LM7 cells through lung endothelial cells was higher than that through liver endothelial cells, and echistatin again inhibited this migration.

CONCLUSIONS

alphavbeta3 integrin expression may play a role in the metastatic potential of osteosarcoma cells by enhancing the ability of the cells to migrate specifically to the lung. Alphavbeta3 integrin may therefore be a potential new target for osteosarcoma.

Increased Fas expression reduces the metastatic potential of human osteosarcoma cells

PURPOSE

The process of metastasis requires the single tumor cell that seeds the metastatic clone to complete a complex series of steps. Identifying factors responsible for these steps is essential in developing and improving targeted therapy for metastasis. Resistance to receptor-mediated cell death, such as the Fas/Fas ligand pathway, is one mechanism commonly exploited by metastatic cell populations.

EXPERIMENTAL DESIGN AND RESULTS

LM7, a subline of the SAOS human osteosarcoma cell line with low Fas expression, was selected for its high metastatic potential in an experimental nude mouse model. When transfected with the full-length Fas gene (LM7-Fas), these cells expressed higher levels of Fas than the parental LM7 cells or LM7-neo control-transfected cells. These cells were also more sensitive to Fas-induced cell death than controls. When injected intravenously into nude mice, the LM7-Fas cell line produced a significantly lower incidence of tumor nodules than control cell lines. Lung weight and tumor nodule size were also decreased in those mice injected with LM7-Fas. Levels of Fas were quantified in osteosarcoma lung nodules from 17 patients. Eight samples were Fas negative, whereas the remaining 9 were only weakly positive compared with normal human liver (positive control).

CONCLUSIONS

Our results demonstrate that altering Fas expression can impact the metastatic potential of osteosarcoma cells. We conclude that the increase of Fas on the surface of the LM7 osteosarcoma cells increased their sensitivity to Fas-induced cell death in the microenvironment of the lung, where Fas ligand is constitutively expressed. Thus, loss of Fas expression is one mechanism by which osteosarcoma cells may evade host resistance mechanisms in the lung, increasing metastatic potential. Fas may therefore be a new therapeutic target for osteosarcoma.

A Small Interfering RNA Targeting Vascular Endothelial Growth Factor Inhibits Ewing's Sarcoma Growth in a Xenograft Mouse Model

Angiogenesis plays an essential role in tumor growth and metastasis and is a promising therapeutic target for cancer. Vascular endothelial growth factor (VEGF) is a key regulator in vasculogenesis as well as in angiogenesis. TC71 human Ewing's sarcoma cells overexpress VEGF, with a shift in isoform production from membrane-bound VEGF189 to the more soluble VEGF165. Transfection of TC71 cells with a vector-based VEGF targeted small interfering RNA expression system (VEGFsi) inhibited VEGF165 expression by 80% and VEGF165 protein production by 98%, with no alteration in VEGF189 expression. Human microvascular endothelial cell proliferation and migration induced by conditioned medium from VEGFsi-transfected TC71 cells was significantly less than that induced by conditioned medium from TC71 cells and control vector-transfected TC71 cells. Furthermore, after s.c. injection into athymic nu/nu mice, the tumor growth of VEGFsi-expressing TC71 cells was significantly less than that of parental or control vector-transfected cells. Vessel density as assessed by CD31 immunohistochemical analysis and VEGF165 expression as assessed by Northern blotting were also decreased. Intratumor gene therapy with polyethylenimine/VEGFsi also resulted in tumor growth suppression. When inoculated into the tibias of nude mice, VEGFsi-expressing TC71 cells induced osteolytic bone lesions that were less severe than those induced by control groups. These data suggest that targeting VEGF165 may provide a therapeutic option for Ewing's sarcoma.

Herceptin Down-Regulates HER-2/neuand Vascular Endothelial Growth Factor Expression and Enhances Taxol-Induced Cytotoxicity of Human Ewing's Sarcoma CellsIn vitroandIn vivo

We have previously shown that high levels of HER-2/neu protein were overexpressed in human Ewing's sarcoma cells (TC71, SK-ES1) relative to normal human osteoblasts. The purpose of this study was to determine whether herceptin alone or in combination with chemotherapeutic agents could inhibit the growth of Ewing's sarcoma in vitro and in vivo. Western blot analysis showed that the protein levels of HER-2/neu were decreased following herceptin treatment. Cell growth was also inhibited by herceptin in a dose-dependent manner with an IC(50) of 4 mg/mL in TC71 and SK-ES1 cell line, whereas human immunoglobin had no effect. Northern blot and ELISA showed the RNA expression and protein levels of vascular endothelial growth factor were also inhibited by herceptin treatment with no alteration in HIF-1alpha protein and topoisomerase IIalpha expression. Furthermore, Ewing's sarcoma tumor growth was significantly delayed by 100 mg/kg herceptin treatment in our Ewing's sarcoma xenograft mouse model. Combining taxol with herceptin resulted in additive cytotoxicity, whereas herceptin-etoposide, doxorubicin, and 9-nitrocamptothecin combinations did not. Taxol-herceptin enhanced growth inhibition in TC71 cells in vitro compared with either agent alone. Ewing's sarcoma growth was also delayed in vivo and mean tumor size was significantly lower in mice treated with herceptin plus taxol than in those receiving taxol or herceptin alone. These data suggest that herceptin in combination with taxol may be a therapeutic option in the treatment of Ewing's sarcoma.

Osterix, a Transcription Factor for Osteoblast Differentiation, Mediates Antitumor Activity in Murine Osteosarcoma

Osterix is a novel zinc finger-containing transcription factor that is essential for osteoblast differentiation and bone formation. We hypothesized that osterix might have a role in osteosarcoma tumor growth and metastasis. Northern blot analysis showed that the mRNA level of osterix was decreased in two mouse osteosarcoma cell lines compared with its level in normal mouse osteoblasts. Osterix expression was also decreased in three human osteosarcoma cell lines. Transfection of the osx gene into the mouse osteosarcoma cells inhibited tumor cell growth in vitro and in vivo and significantly reduced tumor incidence, tumor volume, and lung metastasis following intratibial injection. Osterix expression was also associated with decreased osteolysis. Using an in vitro migration assay, osterix suppressed the migration of tumor cells to lung extracts. These results suggest that osterix expression may play a role in osteosarcoma tumor growth and metastasis.

Interleukin-12 Enhances the Sensitivity of Human Osteosarcoma Cells to 4-Hydroperoxycyclophosphamide by a Mechanism Involving the Fas/Fas-Ligand Pathway

Cyclophosphamide (CY) and its derivative ifosfamide are alkylating agents used to treat osteosarcoma (OS). The purpose of these studies was to determine whether alkylating agents affect the expression of Fas ligand (FasL) and whether interleukin 12 enhances the sensitivity of human OS cells to alkylating agents. 4-Hydroperoxycyclophosphamide (4-HC), the preactivated CY compound, and 4-hydroperoxydidechlorocloclophosphamide (4-HDC), its nonalkylating analogue, human OS LM6 cells, and a clone of cells derived by transfection with the interleukin 12 gene (LM6-#6) were used for these studies. Incubation of LM6 and LM6-#6 with 10 micro M 4-HC increased the expression of FasL mRNA (2.5- and 3.0-fold, respectively). By contrast, 4-HDC, Adriamycin (ADR), cisplatin (CDP), and methotrexate (MTX) had no effect on FasL mRNA expression. Increased FasL expression after treatment with 4-HC was also demonstrated by immunohistochemistry and flow cytometry. Drug-induced FasL was functional and mediated cell death. We examined the effect of FasL up-regulation by 4-HC on LM6 and LM6-#6 cells. Flow cytometry showed that LM6-#6 cells expressed 2.2-fold more Fas than LM6 cells. Cytotoxicity of 4-HC, 4-HDC, ADR, CDP, and MTX on LM6, LM6-neo, and LM6-#6 were quantified. Colony-forming assay revealed an IC(50) of 2.10 micro M for 4-HC in LM6-neo cells compared with 0.41 micro M in LM6-#6 cells. The IC(50) for 4-HDC, ADR, CDP, and MTX were not significantly different between the two cell lines. We concluded that the increased expression of Fas enhanced LM6-#6 sensitivity to 4-HC. These data indicate that Fas/FasL may be involved in the cytotoxic pathway of CY. Combining biological agents with chemotherapeutic agents that have complementary Fas/FasL pathway actions may offer new therapeutic alternatives.

Aerosol gene therapy with PEI: IL-12 eradicates osteosarcoma lung metastases

PURPOSE

We determined whether polyethylenimine (PEI), a polycationic DNA carrier, can be used to deliver the interleukin (IL) 12 gene by aerosol to treat established osteosarcoma (OS) lung metastases in a nude mouse model.

EXPERIMENTAL DESIGN

Tumor response was assessed using our OS lung metastases model. Treatment with aerosolized PEI containing the murine IL-12 gene (PEI:IL-12; 600 microl PEI and 2 mg IL-12) was given twice weekly for 5-6 weeks.

RESULTS

Aerosol therapy for 2 weeks resulted in high expression of both the p35 and p40 subunits of IL-12 in the lungs but not in the livers of mice. Peak IL-12 mRNA expression was seen 24 h after a single aerosol PEI:IL-12 treatment. This expression gradually decreased with continued detection for up to 7 days. IL-12 protein was not detectable in plasma even after 6 weeks of aerosol therapy. The number of lung metastases in mice treated with aerosol PEI:IL-12 was decreased significantly (median, 0; range, 0-33) compared with mice that received PEI alone (median, 37.5; range, 11-125; P = 0.002). Nodule size was also significantly smaller in the aerosol PEI:IL-12 group with 87% of the nodules measuring <or=0.5 mm in diameter compared with 65% in the aerosol PEI group. Mice that received aerosol PEI alone had numerous large lung nodules (3-5 mm). In the aerosol PEI:IL-12 group, no nodules were >1 mm. Weekly aerosol PEI:IL-12 therapy was as effective as twice weekly therapy.

CONCLUSIONS

Aerosol therapy resulted in selective gene expression and protein production in the tumor area. Aerosol PEI:IL-12 may avoid the systemic toxicities described previously in patients treated with i.v. IL-12. Because OS metastasizes almost exclusively to the lung, aerosol PEI:IL-12 therapy may provide a therapeutic option, which may be especially valuable.

Fas expression inversely correlates with metastatic potential in osteosarcoma cells

A complex series of steps must take place to allow for a single cell to metastasize. Identifying factors responsible for these steps is essential in developing targeted therapy. We developed series of osteosarcoma cell lines with differing metastatic potentials. We used them to investigate mechanisms of metastasis and possible therapeutic targets for osteosarcoma metastasis to the lung in a nude mouse model. No correlation was found between epidermal growth factor receptor (EGFR), insulin-like growth factor receptor inhibitor (IGF-I-R), gelatinase, p53, metalloproteinase 9 (MMP 9), platelet derived growth factor receptor (PDGF-R), vascular endothelial growth factor (VEGF) and c-met expression and metastatic potential as measured by Northern analysis. By contrast, Fas expression inversely correlated with metastatic potential, and manipulation of Fas expression altered the metastatic phenotype of the cell. Our data indicate that fas gene expression may offer a new therapeutic target for the treatment of metastatic osteosarcoma in the lung.

Adenovirus-E1A gene therapy enhances the in vivo sensitivity of Ewing's sarcoma to VP-16

This study determined the effect of Ad-E1A gene therapy in vivo. TC71 cells (2 x 10(6)) injected subcutaneously into nude mice resulted in tumor development (1-3 mm) 6 days later. Animals were then treated with Ad-E1A or Ad-beta-gal (5 x 10(9) plaque-forming units) by intratumoral injection twice weekly for 2 weeks. Animals received 8 mg/kg VP-16 given by intraperitoneal injection daily for 5 days following the first week of treatment with Ad-E1A or Ad-beta-gal. Control animals received no therapy or VP-16 only after tumor cells were injected. When tumors exceeded 2 x 2 cm, the mice were sacrificed and the tumors underwent histologic and immunohistochemical analysis. Tumors from mice treated with Ad-E1A plus VP-16 were 9.6-fold smaller than those treated with VP-16 alone and 6.3-fold smaller than those treated with Ad-E1A alone. HER2/neu p185 protein expression decreased in all tumors that received Ad-E1A therapy. TUNEL fluorescence staining revealed more apoptosis in the tumors from animals treated with Ad-E1A plus VP-16 than in those from animals treated with Ad-E1A alone, Ad-beta-gal plus VP-16, or VP-16 alone. These data demonstrated that Ad-E1A gene therapy down-regulated HER2/neu expression, increased tumor cell apoptosis induced by VP-16, and enhanced tumor cell sensitivity to VP-16. Ad-E1A may have potential in the treatment of relapsed drug-resistant Ewing's sarcoma.

Eradication of osteosarcoma lung metastases following intranasal interleukin-12 gene therapy using a nonviral polyethylenimine vector

The use of adenoviral vectors for therapeutic delivery of genes via pulmonary application poses several problems in terms of immune responses. The purpose of this study was to determine whether polyethylenimine (PEI), a polycationic DNA carrier, can be used to deliver the IL-12 gene into the lungs of mice having microscopic osteosarcoma (OS) lung metastases. Incubation of SAOS-LM6 cells in vitro with PEI containing the murine IL-12 (mIL-12) gene (PEI:IL-12) resulted in expression of both the p35 and p40 subunits of IL-12 mRNA and production of mIL-12 protein. Using our newly developed OS nude mouse model, we demonstrated that treatment of mice using intranasal PEI:IL-12 resulted in significant IL-12 mRNA expression in the lung but not the liver. Furthermore, plasma IL-12 was undetectable after up to 4 weeks of intranasal PEI:IL-12 therapy given twice weekly. No IL-12 expression was seen following intranasal PEI therapy alone. The number of lung metastases in animals that received intranasal PEI:IL-12 twice weekly for 4 weeks starting 6 weeks after tumor inoculation was significantly decreased (median, 11; range, 0-47) compared with those that received PEI alone (median, 89; range, 2 to >200; P=.012). Also, the size of the nodules was significantly smaller in the PEI:IL-12-treated animals, with 90% measuring < or =0.5 mm in diameter compared with 56% in the PEI-alone group. Animals that received PEI alone also had numerous large nodules (3-6 mm) throughout the lungs. Intranasal therapy is a noninvasive way to administer agents and has the advantage of targeting the pulmonary region, resulting in higher concentrations in the tumor area. Additionally, delivery of IL-12 to the lung via the airway using PEI may avoid systemic toxicity. Because OS metastasizes almost exclusively to the lung, this may be a novel approach to the treatment of pulmonary OS metastases.

Eradication of osteosarcoma lung metastasis using intranasal gemcitabine

We sought to determine whether gemcitabine, a new pyrimidine antimetabolite, could inhibit the growth of human osteosarcoma cells (OS) in vitro and in vivo. Four human OS cell lines (MG-63, TE-85, SAOS-2 and SAOS-LM7) were used to assess the activity of the drug in vitro. Gemcitabine caused growth inhibition and cell death in all four cell lines as measured using the MTT and colony-forming assays (IC(50) = 6.5 nM-9 microM and 7-14 nM, respectively). Using our newly developed human SAOS-LM7 OS lung metastasis mouse model, we assessed the in vivo activity of gemcitabine given i.p. and intranasally (i.n.). Mice were treated twice weekly for 3 weeks and then once weekly for 3 weeks using either i.p. or i.n. gemcitabine starting 4 weeks after tumor cell injection. The i.p. injection, at 120 mg/kg, resulted in a decrease in lung weights and the size of the nodules. However, no significant reduction in the number of metastatic nodules was seen (control median: >200 versus gemcitabine median: 150, p = 0.084). In contrast, the number of lung metastases was significantly decreased in mice that received i.n. gemcitabine at 15 (median: 1; range: 0-115, p<0.005) and 12 mg/kg (median: 41; range: 7-163, p = 0.005) when compared with control mice (median: >200). Intranasal therapy is a non-invasive method of drug delivery and has the advantage of targeting the lung, resulting in a higher drug concentration in the tumor area. In our study, i.n. instillation of gemcitabine inhibited the growth of lung metastases at an 8- to 10-fold lower dose than that used i.p. and appeared to be more effective in eradicating OS lung nodules. Because the lung is the most common site of OS metastasis, our data suggest that i.n. gemcitabine may be a novel therapeutic approach in the treatment of OS lung metastases.

Interleukin-1 alpha increases the cytotoxic activity of etoposide against human osteosarcoma cells

The recurrence of pulmonary metastases resistant to salvage chemotherapy continues to be a major problem in osteosarcoma patients. Our goal is to identify novel combinations of biologic response modifiers plus chemotherapeutic agents that can be translated into clinical trials. Response rates of relapsed osteosarcoma patients to etoposide have been extremely low. The present investigation demonstrated that IL-1 alpha dramatically increased the sensitivity of MG-63, SAOS-2, and TE-85 osteosarcoma cells to etoposide when the two agents were used simultaneously. The cytostatic activity of 1 microM etoposide was increased from 35 to 70%, 30 to 65%, and 4 to 90%, respectively, by 5.0 U/ml IL-1 alpha. Analysis using the colony-forming assay to quantify cytotoxicity showed that the percentage of cell survival following exposure to etoposide decreased from 0.81 to 0.56, 0.55 to 0.2, and 0.4 to 0.05 when the combination treatment was used. Increased sensitivity was not seen when etoposide treatment preceded IL-1 alpha treatment. IL-1 alpha also increased the sensitivity of these cells to doxorubicin but not to cisplatin or topotecan. The mechanism of this enhanced activity is independent of p-glycoprotein, drug-uptake, or effects on topoisomerase II.

Growth suppression of established human osteosarcoma lung metastases in mice by aerosol gene therapy with PEI-p53 complexes

Lung metastases are a frequent complication of osteosarcoma and a treatment that would reduce the severity of this complication would be of great benefit to patients. We have used a formulation consisting of polyethyleneimine (PEI) and a p53 gene administered in aerosol to treat established lung micrometastases as a model of human osteosarcoma in nude mice. The SAOS-LM6 cell line, a metastatic derivative of the p53 null SAOS-2 line, expresses high levels of p53 protein after in vitro transfection with PEI-p53 complexes as determined by ELISA, and transfection with both p53wt and the p53 variant, p53-CD(1-366) in vitro, results in a marked inhibition of SAOS-LM6 cell proliferation. Aerosol delivery of plasmid DNA containing either the p53 gene or a p53-CD(1-366) variant gene formulated with PEI to mice resulted in highly significant reductions in the numbers and size of tumors (P<.001), the total number of tumor foci in the lungs (P<.001) and the size of individual tumor nodules in treated animals compared to untreated, PEI only-treated and PEI-CAT-treated control animals. The different tissues examined did not reveal any signs of toxicity or inflammation after repeated exposure to PEI-DNA. The aerosol delivery of PEI-based formulations of p53 or synthetic p53 variant genes represents a promising new strategy for the treatment of established human osteosarcoma lung metastases. The noninvasive nature of aerosol delivery coupled with low toxicity also make this therapeutic approach potentially appropriate for combination therapy with either radio- or chemotherapy.

Interleukin (IL)-12 and IL-12 gene transfer up-regulate Fas expression in human osteosarcoma and breast cancer cells

Expression of Fas (CD95, APO-1), a cell surface receptor capable of inducing ligand-mediated apoptosis, is involved in tissue homeostasis and elimination of targeted cells by natural killer and T cells. Corruption of this pathway, such as reduced Fas expression, can allow tumor cells to escape elimination and promote metastatic potential. In this study, the status of Fas expression has been examined in the parental SAOS human osteosarcoma cells that do not metastasize and in selected variants that cause lung metastases in 16 weeks (LM2) or 8 weeks (LM6) after i.v. injection into nude mice. Fas expression correlated with the metastatic potentials of the three cell lines. Northern and fluorescence-activated cell-sorting analyses indicated that LM6 cells expressed Fas at a lower level than seen in the parental cells. Infection of the LM6 cells with an adenoviral vector containing the murine interleukin (IL)-12 gene (AD:mIL-12) or treatment with recombinant murine IL-12 resulted in a dose-dependent up-regulation of FAS: The up-regulation of Fas by IL-12 was also demonstrated in human etoposide-resistant MDA-MB-231 breast cancer cells. [(3)H]Thymidine growth inhibition studies indicated that the cell surface Fas induced after IL-12 exposure was functional and able to mediate cell death on cross-linking with anti-FAS: We also demonstrate that this effect is independent of IFN-gamma. Whereas these cell lines are sensitive to IFN-gamma, incubation with IFN-gamma does not increase susceptibility to Fas-mediated cell death, nor do these cells produce IFN-gamma with or without IL-12 treatment. We hypothesize that expression of Fas may play a role in the elimination of metastatic tumor cells in the lung, an organ in which Fas ligand is expressed. The antitumor activity of IL-12 may be secondary in part to its ability to up-regulate Fas expression on tumor cells, which subsequently increases immune-mediated destruction of osteosarcoma cells.

E1A sensitizes HER2/neu-overexpressing Ewing's sarcoma cells to topoisomerase II-targeting anticancer drugs

Overexpression of the HER2/neu oncogene is associated with tumorigenicity and drug resistance in many types of cancer. Three different human Ewing's sarcoma cell lines (TC71, RD, and A4573) were found to express high levels of the HER2/neu protein. Transduction of TC71 cells with the E1A gene using an adenoviral vector (Ad-E1A) down-regulated HER2/neu overexpression in those cells and increased cytostasis. E1A-induced apoptosis was demonstrated by both flow cytometric analysis and Western blot analysis using a poly(ADP-ribose) polymerase antibody. After transduction of the E1A gene into these cells, the sensitivity of these cells to VP-16 (etoposide) was enhanced 18-fold and to Adriamycin 5-fold. However, no change was seen in cisplatin sensitivity. E1A also significantly increased topoisomerase IIalpha protein expression, indicating that the up-regulation of topoisomerase IIalpha may be one of the mechanisms by which E1A enhanced the sensitivity to topoisomerase II-targeting anticancer drugs, such as VP-16 and Adriamycin, but not cisplatin. In summary, these studies demonstrated that Ad-E1A can down-regulate HER2/neu overexpression and up-regulate topoisomerase IIalpha expression in human Ewing's sarcoma cells, increasing their apoptosis rate and enhancing their sensitivity to VP-16 and ADRIAMYCIN:

Intranasal therapy with an adenoviral vector containing the murine interleukin-12 gene eradicates osteosarcoma lung metastases

The purpose of these studies was to determine the effect of adenovirus-mediated interleukin-12 (IL-12) gene transfer on the growth and development of osteosarcoma (OS) lung metastases in nude mice. A nude mouse model was produced by repetitive cycling of human SAOS OS cells through the lung. The resultant SAOS-LM6 cell line produced microscopic lung metastases by 5-6 weeks after i.v. injection of the tumor cells, with visible lung metastases present 8 weeks after injection. Transfection of SAOS-LM6 cells with a plasmid containing the murine IL-12 gene resulted in a decrease in metastatic potential. Animals injected with IL-12-transfected clones had fewer metastases compared with mice injected with SAOS-LM6 cells transfected with a control plasmid. Furthermore, nasal delivery of an adenoviral vector containing the murine IL-12 gene resulted in the inhibition of pulmonary metastases. Together, these data indicate that IL-12 may be an effective agent against OS and that nasal delivery may offer a unique way to deliver the gene to the local tumor environment, potentially decreasing systemic toxic effects.

9-Nitrocamptothecin liposome aerosol treatment of melanoma and osteosarcoma lung metastases in mice

The response rates of relapsed osteosarcoma and melanoma pulmonary metastases to traditional i.v. chemotherapeutic regimens have been disappointing. Direct drug delivery of chemotherapy to the lungs could increase the drug concentration in the tumor area and may offer a new therapeutic approach for these patients. Previous studies demonstrated that drugs delivered to the respiratory tract in liposomal formulation resulted in high pulmonary drug concentration, reduced systemic toxicity, and reduced dosage requirements compared with parenteral and oral administration. To determine whether this approach has utility against pulmonary metastases, the efficacy of aerosol therapy with liposome-encapsulated 9-nitrocamptothecin (L-9NC) was determined using two different experimental lung metastasis models. C57BL/6 mice were treated the day after the i.v. injection of B16 melanoma cells with aerosol L-9NC for 1 h (153 microg 9-nitrocamptothecin/kg) for 5 days per week for up to 3 weeks. Aerosol L-9NC treatment resulted in a reduction in lung weights (P = 0.005) and number of tumor foci (P < 0.001). Visible tumor nodules were fewer and smaller in the 9-nitrocamptothecin-treated group than in untreated control mice (P < 0.001). Using a newly developed human osteosarcoma experimental metastasis model in nude mice, we demonstrated that aerosol L-9NC was also effective against established lung metastases. Aerosol therapy initiated on the ninth week after i.v. tumor injection and continued for 8 or 10 weeks produced highly significant reductions in the number of animals with both visible and microscopic disease (P < 0.02), the total number of tumor foci in the lungs (P < 0.005), and the size of the individual tumor nodules (P < 0.02). These data suggest that L-9NC aerosol therapy may offer significant advantage over existing methods in the treatment of melanoma and osteosarcoma pulmonary metastases.

A nude mouse model of human osteosarcoma lung metastases for evaluating new therapeutic strategies

The purpose of these studies was to develop a metastatic osteosarcoma nude mouse model to evaluate the in vivo efficacy of new therapeutic compounds. Human SAOS-2 osteosarcoma cells (10(6) cells) were injected i.v. into nude mice. Cells isolated from a rare pulmonary metastases 6 months later were established (SAOS-LM1) in culture and re-injected. This procedure was repeated 5 additional times to produce the SAOS-LM6 cell line. Visible pulmonary nodules were present 8 weeks following i.v. injection of 10(6) SAOS-LM6 cells as compared to 17 weeks using SAOS-LM2 cells. Microscopic SAOS-LM6 pulmonary metastases were demonstrated at 6 weeks. Administration of adriamycin on week 9 resulted in regression of macroscopic SAOS-LM6 lung tumors. The ability of the model to be used to evaluate the effectiveness of a biologic agent against microscopic disease was also verified. It was concluded that this model can assess therapeutic efficacy and therefore, may have a role in investigating the potential of novel approaches aimed at eliminating pulmonary metastatic osteosarcoma.

ImmTher, a lipophilic disaccharide derivative of muramyl dipeptide, up-regulates specific monocyte cytokine genes and activates monocyte-mediated tumoricidal activity

ImmTher, a liposome-encapsulated lipophilic disaccharide tripeptide derivative of muramyl dipeptide, previously showed activity against liver and lung colorectal metastases in a phase I trial. The purpose of the current studies was to investigate whether ImmTher could up-regulate specific cytokine gene expression and protein production, as well as activate the tumoricidal or cytostatic activity of human monocytes. ImmTher induced the expression and production of interleukin(IL)-1alpha IL-1beta, IL-6, IL-8, IL-12, macrophage chemotactic and activating factor, and tumor necrosis factor alpha but not IL-2 or IL-10. Cytostatic or cytotoxic monocyte activity was stimulated against human Ewing's sarcoma, osteosarcoma, and melanoma cells but not breast cancer cells. Production and secretion of these cytokine proteins may play a role in the antitumor activity of ImmTher.

Interferon-alpha enhances the sensitivity of human osteosarcoma cells to etoposide

The purpose of these studies was to determine whether interferon-alpha (IFN-alpha) could enhance the sensitivity of human osteosarcoma cells to the cytotoxic actions of etoposide (VP-16). Cytostasis was determined using a [3H]thymidine incorporation assay, whereas cytotoxicity was quantified by a colony-formation assay. Low concentrations (0.1-5 U/ml) of IFN-alpha enhanced the cytostatic activity of VP-16 against MG-63, SAOS-2, and TE-85 osteosarcoma cells. The cytostatic activity of 1 microM VP-16 rose from 11% to 64%, 9% to 31%, and 10% to 71%, respectively, in the three cell lines when IFN-alpha was present. Survival fraction was also decreased when the osteosarcoma cells were treated with VP-16 + IFN-alpha as compared to either agent alone. The interaction between these two agents was determined to be synergistic rather than additive by interaction index analysis. Similar effects on cytostasis and cytotoxicity were observed when IFN-alpha was combined with Adriamycin but not cisplatin, actinomycin D, vinblastine, or amsacrine. VP-16 uptake was enhanced 12-fold in the presence of IFN-alpha, but this did not appear to translate into an increase in topoisomerase-II (topo-II)-DNA complex formation as quantified by the sodium dodecyl sulfate-KCl precipitation assay. We also could not detect alterations in topo-II expression, topo-II protein production, or cell cycle kinetics that have been shown to correlate with increased VP-16 cell sensitivity. Therefore, at this time the mechanism of enhanced cell sensitivity to the combination treatment remains unclear.

Phase II study of recombinant interleukin 1alpha and etoposide in patients with relapsed osteosarcoma

A Phase II trial using interleukin 1alpha (IL-1alpha) and etoposide for patients with relapsed osteosarcoma (OS) was undertaken to assess the feasibility and tolerability of combination therapy with biotherapy and chemotherapy. Nine patients with histologically proven relapsed OS were treated with IL-1alpha immediately followed by etoposide daily for 5 days every 3 weeks. Surgical resection of lung metastasis or peripheral tumor was performed after two or three cycles. We observed three partial responses; disease was stable in another case. One case could not be evaluated. The side effects associated with combination therapy were as predicted from known side effects of the individual agents; however, more profound neutropenia was observed. Four patients exhibited clinical signs of capillary leak syndrome, i.e., hypotension, edema, and weight gain. The etiology of the capillary leak was unclear, because serum IL-1alpha, IL-2, tumor necrosis factor, and nitric oxide levels could not be used to predict which patients would develop capillary leak. Histological analysis of tumor specimens obtained after two or more courses of therapy showed changes consistent with a response to a biological response modifier: peripheral fibrosis surrounded the metastasis with infiltration of chronic and acute inflammatory cells. Because the response of relapsed OS to any type of salvage regimen has been poor, we interpret the clinical response of this therapy as good. However, the significant side effects associated with this therapy must also be taken into consideration before deciding to use this combination therapy. It is unfortunate that the study was stopped early due to halted production of IL-1alpha. If this agent is again manufactured for clinical use, we conclude that additional evaluation in patients with relapsed OS is warranted.

Altered monocyte chemotactic and activating factor gene expression in human glioblastoma cell lines increased their susceptibility to cytotoxicity

A cDNA encoding for human monocyte chemotactic and activating factor (MCAF) was ligated into the retroviral vector pLXSN. These pMCAF-LXSN and antisense p-antiMCAF-LXSN vectors were transfected into HBT20 and HBT28 human brain tumor cells. HBT28 cells constitutively express high amounts of MCAF, whereas HBT20 cells express much less MCAF. HBT20 cells transfected with pMCAF-LXSN (HBT20-MCAF) showed significantly higher MCAF mRNA expression and MCAF protein production than the HBT20-parent or HBT20 cells transfected with control vector (HBT20-LXSN). In contrast, supernatant from HBT28 cells transfected with p-antiMCAF-LXSN (HBT28-antiMCAF) contained less MCAF than HBT28-parent, HBT28-LXSN, and HBT28-MCAF cells. Activated human monocytes killed HBT20-MCAF cells more efficiently compared with HBT20-parent, HBT20-LXSN, and HBT20-antiMCAF cells (P< 0.02), whereas HBT28-antiMCAF cells were killed more efficiently by activated monocytes compared with HBT28-parent, HBT28-LXSN, and HBT28-MCAF cells (P< 0.05). Cultured supernatants from activated monocytes plus HBT20-MCAF cells or from activated monocytes plus HBT28-antiMCAF cells inhibited the growth of HBT20 and HBT28 cells, respectively. Altered MCAF expression can therefore enhance the ability of activated monocytes to kill brain tumor cells. This increased cytotoxicity is partially dependent upon the basal state of MCAF in the individual tumor cells.

Phase Ia/Ib trial of anti-GD2 chimeric monoclonal antibody 14.18 (ch14.18) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in metastatic melanoma

We performed a phase Ia/Ib trial of chimeric anti-GD2 monoclonal antibody 14.18 (ch14.18) in combination with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) to determine the maximum tolerated dose as well as immunologic and biologic responses to the regimen. Sixteen patients with metastatic malignant melanoma received escalating doses of ch14.18 (15-60 mg/m2) administered intravenously for 4 h on day 1. Twenty-four hours later, subcutaneous injections of rhGM-CSF were administered daily for a total of 14 days. Significant side effects were related to ch14.18 infusion and consisted of moderate to severe abdominal and/or extremity pain, blood pressure changes, headache, nausea, diarrhea, peripheral nerve dysesthesias, myalgias, and weakness. Dose-limiting toxicity was observed at 60 mg/m2 and consisted of severe hypertension, hypotension, and atrial fibrillation in one patient each, respectively. Significant increases in white blood cell count, granulocyte count, eosinophil count, and monocyte count occurred after rhGM-CSF treatment. Significant enhancement of in vitro and in vivo monocyte and neutrophil tumoricidal activity and antibody-dependent cellular cytotoxicity along with significant elevations in C-reactive protein and neopterin were observed. Despite these immunological and biological changes, no antitumor activity was seen. In short, the combination of ch14.18 and rhGM-CSF resulted in toxicity similar to that observed with ch14.18 alone without improvement in tumor response.

Combination therapy with ifosfamide and liposome-encapsulated muramyl tripeptide: tolerability, toxicity, and immune stimulation

A phase IIb trial using liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) in combination with ifosfamide (IFX) for patients with relapsed osteosarcoma was undertaken to determine (a) the tolerability of the combination therapy, (b) if L-MTP-PE increased the toxicity of IFX, and (c) whether IFX altered or suppressed the in vivo immune response to L-MTP-PE. Patients had histologically proven osteosarcoma and pulmonary metastases that either developed during adjuvant chemotherapy or were present at diagnosis, persisted despite chemotherapy, and recurred following surgical excision. Stratum A patients were rendered clinically free of disease within 4 weeks of study entry prior to receiving combination therapy. IFX was administered at 1.8 g/m2 for 5 days every 21 days for up to eight cycles. L-MTP-PE was administered twice weekly for 12 weeks, then once weekly for 12 weeks. Once cycle of combination therapy was defined as 5 days of IFX and 3 weeks of L-MTP-PE therapy. Stratum B patients had measurable disease at study entry that was judged to be amenable to surgical resection. Stratum B patients received three cycles of combination therapy prior to surgery to judge clinical and histologic response. Postoperatively, patients received an additional five cycles. A total of nine patients were entered into the protocol: six on stratum A and three on stratum B. Serial blood samples were collected and assayed for cytokine levels (tumor necrosis factor-alpha [TNF alpha], interleukin-6 [IL-6], IL-8, neopterin, C-reactive protein). In addition, peripheral blood monocyte tumoricidal activity was evaluated pre- and post-combination therapy. Complete blood counts with differential and platelet counts were followed weekly. No increase in the toxic side effects of IFX was demonstrated when administered with L-MTP-PE nor were delays in IFX administration due to neutropenia experienced. The toxic side effects of L-MTP-PE were also not increased. Elevations of serum C-reactive protein, plasma neopterin, IL-6, IL-8, and TNF alpha following combination therapy were similar to those observed in patients treated with L-MTP-PE alone. Monocyte-mediated tumoricidal activity was elevated 24 and 72 h following L-MTP-PE and IFX therapy, similar to what has been reported following L-MTP-PE alone. Tumor specimens obtained from stratum B patients showed the histologic characteristics consistent with a "chemotherapy effect," i.e., dead, amorphous, acellular osteoid with cell drop-out.(ABSTRACT TRUNCATED AT 400 WORDS)

Phase II study of liposomal muramyl tripeptide in osteosarcoma: the cytokine cascade and monocyte activation following administration

PURPOSE

A phase II trial that uses liposome-encapsulated muramyl tripeptide phosphatidylethanolamine (L-MTP-PE) in patients with relapsed osteosarcoma is underway. To determine if in vivo cytokine induction plays a role in the mechanism of action of L-MTP-PE, we investigated the circulating cytokine levels of 16 patients who were undergoing therapy.

PATIENTS AND METHODS

Patients had histologically proven osteosarcoma and pulmonary metastases that developed either during adjuvant chemotherapy or that were present at diagnosis and persisted despite chemotherapy. Patients were rendered disease-free by surgery. The major goal of the study was to improve the disease-free interval in this high-risk group. L-MTP-PE 2 mg/m2 was infused during a 1-hour period twice a week for 12 weeks, then once a week for 12 weeks. Serial blood samples were collected after L-MTP-PE administration and were assayed for cytokine levels (tumor necrosis factor-alpha [TNF alpha] interleukin-1 alpha [IL-1 alpha], IL-1 beta, IL-6, interferon-gamma [IFN-gamma], neopterin, C-reactive protein).

RESULTS

After the infusion of L-MTP-PE, there was rapid induction of circulating TNF alpha and IL-6. TNF alpha levels peaked 1 to 2 hours after infusion in 10 of 16 patients, whereas peak IL-6 levels were detected at 2 to 3 hours in all patients. Induction of circulating TNF alpha and IL-6 was evident only after the first dose of L-MTP-PE. Neither IL-1 alpha nor IL-1 beta was detected in the plasma. Neopterin levels increased at 24 hours postinfusion, which indicated macrophage activation, and were not related to the induction of circulating IFN-gamma. C-reactive protein was elevated in all patients at 24 hours and decreased by 72 hours. Unlike circulating TNF alpha and IL-6, elevations in C-reactive protein and neopterin could be detected throughout the treatment course.

CONCLUSION

It is concluded that L-MTP-PE has specific biologic effects in patients with osteosarcoma that may be important to the drug's immunostimulatory capacity and its effectiveness as an antitumor agent.

Antitumor activity of TNF-alpha, IL-1, and IFN-gamma against three human osteosarcoma cell lines

Osteosarcoma is the most common primary malignant bone tumor. The peak incidence is in adolescence and the prognosis is very poor. Even after amputation and chemotherapy, many patients who suffer from osteosarcoma die of lung metastases within 2 years. This report documents a study of the in vitro antitumor activity of cytokines against three human osteosarcoma cell lines. The cell lines MG-63, SAOS-2, and TE-85 were incubated with TNF-alpha, IL-1, or IFN-gamma alone or in combination. TNF-alpha, IL-1, and IFN-gamma had antiproliferative activity against all three cell lines. TNF-alpha and IFN-gamma were the most effective against SAOS-2; MG-63 cells were the most sensitive to IL-1, and TE-85 cells were resistant to TNF-alpha and IL-1 but sensitive to IFN-gamma. The synergistic antitumor effect of TNF-alpha plus IFN-gamma, IL-1 alpha, or IL-1 beta or of IFN-gamma plus IL-1 alpha or IL-1 beta was higher than that obtained when the cytokines were employed alone.