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Manfred Schmitt

Publications and source records attributed to Manfred Schmitt.

72 records · Page 4Linked to original sources
PubMed2003

Considerations on development, validation, application, and quality control of immuno(metric) biomarker assays in clinical cancer research: an EORTC-NCI working group report.

A major dilemma associated with immuno(metric) assays for biomarkers is that various kits employing antibodies with differing specificities and binding affinities may generate non-equivalent test results. Also, variation in sample processing and the use of different standards (reference material) may result in discordant test results. Therefore, assays and procedures should be standardized and the quality of biomarker assay results should be monitored by continuous between-laboratory proficiency testing of performance. External quality control requires an established network of expert laboratories in which the investigators interact freely and where technical issues are discussed. Although such networking is more often praised than practiced, we strongly endorse and advocate between-laboratory exchange of experience and information. The present study discusses analytical aspects of immuno(metric) biomarker assays and presents recommendations of the Receptor and Biomarker Group of the EORTC (European Organisation for Research and Treatment of Cancer) how such tests should be validated for first time and day to day use. Moreover, a model for an appropriate quality assurance program is presented.

Biomarkers, Tumor↗
PubMed2002

Synthesis, solution structure, and biological evaluation of urokinase type plasminogen activator (uPA)-derived receptor binding domain mimetics.

Tumor cell migration and metastasis in cancer are facilitated by interaction of the serine protease urokinase type plasminogen activator (uPA) with its receptor uPAR (CD 87). Overexpression of uPA and uPAR in cancer tissues is associated with a high incidence of disease recurrence and early death. In agreement with these findings, disruption of the protein-protein interaction between uPAR present on tumor cells and its ligand uPA evolved as an attractive intervention strategy to impair tumor growth and metastasis. For this, the uPAR antagonist cyclo[19,31][D-Cys(19)]-uPA(19)(-)(31) was optimized to efficiently interrupt binding of uPA to cellular uPAR. First, the disulfide bridge of this lead compound was shifted and then the modified peptide was shortened from the amino and carboxy terminus to generate cyclo[21,29][Cys(21,29)]-uPA(21)(-)(30). Next, cyclo[21,29][D-Cys(21)Cys(29)]-uPA(21)(-)(30) was yielded by changing the chirality of Cys(21) to D-Cys(21). For analysis of uPAR binding activity, we employed competitive flow cytofluorometric receptor binding assays, using FITC-uPA as the ligand and U937 promyeloid leukemia cells as the cellular source of uPAR. As demonstrated for cyclo[21,29][D-Cys(21)Cys(29)]-uPA(21)(-)(30), the achieved peptide modifications maintained receptor binding activity (IC(50) = 0.04 microM), which is close in order to that of the parent protein ligand, uPA (IC(50) = 0.01 microM). A detailed NMR analysis with restrained and free molecular dynamics calculations in explicit H(2)O exhibits a well-defined structure with characteristic features such as an omega-loop with two betaI-turns about Lys(3), Tyr(4), Ser(6), and Asn(7). Hydrophobic clustering of the side chains of Tyr(4), Phe(5), Ile(8), and Trp(10) is observed. Side chain mobility is analyzed with time-dependent distance restraints. The NMR structure of cyclo[21,29][D-Cys(21)Cys(29)]-uPA(21)(-)(30) is very similar to the previously reported structure of the amino terminal fragment of uPA. Systematic point mutations led to cyclo[21,29][D-Cys(21)Nle(23)Cys(29)]-uPA(21)(-)(30), which still binds to uPAR but is resistant to proteolytic cleavage, e.g., by the tumor-associated serine proteases uPA and plasmin, and is stable in blood serum or plasma. In conclusion, small cyclic peptides were created, which mimic the structure and activity of the binding epitope of uPA to uPAR and which may serve as novel therapeutic agents in cancer metastasis.

Antineoplastic Agents↗
PubMed2002

High-affinity urokinase-derived cyclic peptides inhibiting urokinase/urokinase receptor-interaction: effects on tumor growth and spread.

Urokinase-type plasminogen activator (uPA) binds with high affinity to its specific cell surface receptor (uPAR) (CD87) via a well-defined sequence within the N-terminal region of uPA (uPA(19-31)). Since this uPA/uPAR-interaction plays a significant role in tumor cell invasion and metastasis, it has become an attractive therapeutic target. Two small peptidic cyclic competitive antagonists of uPA/uPAR-interaction have been developed, based on the uPAR binding site in uPA: WX-360 (cyclo(21,29)[D-Cys21]-uPA(21-30)[S21C;H29C]) and its norleucine (Nle) derivative WX-360-Nle (cyclo(21,29)[D-Cys21]-uPA(21-30)[S21C;K23Nle;H29C]). These peptides display an only five to 10-fold lower affinity to uPAR as compared to the naturally occurring uPAR-ligand uPA. In this study, WX-360 and WX-360-Nle were tested in nude mice for their potency to inhibit tumor growth and intraperitoneal spread of lacZ-tagged human ovarian cancer cells. Intraperitoneal administration of either cyclic peptide (20 mg peptide/kg; 1x daily for 37 days) into the tumor-bearing nude mice resulted in a significant reduction of tumor weight and spread within the peritoneum as compared to the untreated control group. This is the first report demonstrating effective reduction of tumor growth and spread of human ovarian cancer cells in vivo by small synthetic uPA-derived cyclic peptides competitively interfering with uPA/uPAR-interaction. Thus, both WX-360 and WX-360-Nle are promising novel compounds to reduce dissemination of human ovarian carcinoma.

Animals↗
PubMed2002

Enhanced benefit from adjuvant chemotherapy in breast cancer patients classified high-risk according to urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (n = 3424).

Risk assessment and prediction of response to treatment are prerequisites for individualized adjuvant therapy decisions in breast cancer. The strong prognostic impact of the two invasion factors urokinase-type plasminogen activator (uPA) and its inhibitor, plasminogen activator inhibitor type 1 (PAI-1), in breast cancer has recently been validated at level-I evidence. This article considers the predictive impact of uPA/PAI-1 on response to adjuvant chemo- and endocrine therapy in 3424 primary breast cancer patients from two different data sets. uPA and PAI-1 antigen levels were measured by ELISA in primary tumor tissue extracts. After a median follow-up of 83 months, uPA/PAI-1 has a significant impact on disease-free survival in Cox multivariate analysis (P < 0.001; hazard ratio, 2.0; 95% confidence interval, 1.8-2.3). Patients with high uPA/PAI-1 levels benefit more strongly from adjuvant chemotherapy than those with low levels. This effect is seen as a significant interaction between chemotherapy and uPA/PAI-1 for the entire collective (P < 0.003; hazard ratio, 0.68; 95% confidence interval, 0.53-0.88) and separately within nodal subgroups. This enhanced benefit in the high uPA/PAI-1 patients occurs over and above the significant impact of both therapies in all patients. We find no corresponding significant interaction between endocrine therapy and uPA/PAI-1; i.e., no significant difference in benefit between patients with high and low uPA/PAI-1. In conclusion, uPA and PAI-1 levels in primary tumor tissue provide clinically relevant information on relapse risk and treatment response that will help to tailor adjuvant therapy concepts in breast cancer, accounting for individual biological tumor characteristics.

Adult↗
PubMed2002

Clinical relevance of invasion factors urokinase-type plasminogen activator and plasminogen activator inhibitor type 1 for individualized therapy decisions in primary breast cancer is greatest when used in combination.

PURPOSE: A strong prognostic impact of urokinase-type plasminogen activator (uPA) and its inhibitor and plasminogen activator inhibitor type 1 (PAI-1) as individual factors is well established in breast cancer. The improvement in clinical risk assessment gained by combining these factors is evaluated here. PATIENTS AND METHODS: uPA and PAI-1 levels were prospectively measured by enzyme-linked immunosorbent assay in tumor tissue extracts of 761 patients with primary breast cancer. RESULTS: In the clinically important subgroup of node-negative patients without adjuvant systemic therapy (n = 269; median follow-up, 60 months), the clinical value of testing both uPA and PAI-1 is demonstrated. The criterion either or both high identifies with high sensitivity the patients at high relapse risk while keeping more than half in the low-risk group. uPA/PAI-1 is the strongest predictor of disease-free survival and overall survival; patients with high uPA/PAI-1 have an increased relapse risk (P <.001; relative risk, 4.8; 95% confidence interval [CI], 2.5 to 9.1), in particular for early relapse. Even within risk groups stratified by established criteria (nodal or menopausal status, tumor size, grade, or steroid hormone receptors), uPA/PAI-1 provides significant risk group discrimination. In the whole collective, the significant interaction between uPA/PAI-1 and adjuvant systemic therapy suggests a benefit from adjuvant therapy in high-risk patients as defined by uPA/PAI-1. CONCLUSION: The clinical relevance of the two tumor-invasion factors uPA and PAI-1 is greatest when they are used in combination. The particular combination of uPA and PAI-1 (both low v either or both high) is superior to either factor alone and supports risk-adapted individualized therapy decisions.

Adult↗
PubMed2002

Cancer progression and tumor cell motility are associated with the FGFR4 Arg(388) allele.

Expression analysis of genes encoding components of the phosphotyrosine signaling system by cDNA array hybridization revealed elevated levels of FGFR4 transcripts in several mammary carcinoma cell lines. In the FGFR4 gene transcript from MDA-MB-453 mammary carcinoma cells, a G to A conversion was discovered that results in the substitution of glycine by arginine at position 388 in the transmembrane domain of the receptor. The Arg(388) allele was also found in cell lines derived from a variety of other tumor types as well as in the germ-line of cancer patients and healthy individuals. Analysis of three geographically separated groups indicated that it occurs in approximately 50% of the human population. Investigation of the clinical data of 84 breast cancer patients revealed that homo- or heterozygous carriers of the Arg(388) allele had a significantly reduced disease-free survival time (P = 0.01) within a median follow-up of 62 months. Moreover, the FGFR4 Arg(388) allele was associated with early lymph node metastasis and advanced tumor-node-metastasis (TNM) stage in 82 colon cancer patients. Consistent with this finding, MDA-MB-231 mammary tumor cells expressing FGFR4 Arg(388) exhibited increased motility relative to cells expressing the FGFR4 Gly(388) isotype. Our results support the conclusion that the FGFR4 Arg(388) allele represents a determinant that is innocuous in healthy individuals but predisposes cancer patients for significantly accelerated disease progression.

Alleles↗
PubMed2002

Y-box factor YB-1 predicts drug resistance and patient outcome in breast cancer independent of clinically relevant tumor biologic factors HER2, uPA and PAI-1.

Intrinsic or acquired resistance to chemotherapy is responsible for failure of current treatment regimens in breast cancer patients. The Y-box protein YB-1 regulates expression of the P-glycoprotein gene mdr1, which plays a major role in the development of a multidrug-resistant tumor phenotype. In human breast cancer, overexpression and nuclear localization of YB-1 is associated with upregulation of P-glycoprotein. In our pilot study, we analyzed the clinical relevance of YB-1 expression in breast cancer (n = 83) after a median follow-up of 61 months and compared it with tumor-biologic factors already used for clinical risk-group discrimination, i.e., HER2, urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1). High YB-1 expression in tumor tissue and surrounding benign breast epithelial cells was significantly associated with poor patient outcome. In patients who received postoperative chemotherapy, the 5-year relapse rate was 66% in patients with high YB-1 expression. In contrast, in patients with low YB-1 expressions, no relapse has been observed so far. YB-1 expression thus indicates clinical drug resistance in breast cancer. Moreover, YB-1 correlates with breast cancer aggressiveness: in patients not treated with postoperative chemotherapy, those with low YB-1 expression are still free of disease, whereas the 5-year relapse rate in those with high YB-1 was 30%. There was no significant correlation between YB-1 expression and either HER2 expression or uPA and PAI-1 levels. Risk-group assessment achieved by YB-1 differed significantly from that by HER2 or uPA/PAI-1. In conclusion, YB-1 demonstrated prognostic and predictive significance in breast cancer by identifying high-risk patients in both the presence and absence of postoperative chemotherapy, independent of tumor-biologic factors currently available for clinical decision making.

Adult↗
PubMed2002

Pooled analysis of prognostic impact of urokinase-type plasminogen activator and its inhibitor PAI-1 in 8377 breast cancer patients.

BACKGROUND: Urokinase-type plasminogen activator (uPA) and its inhibitor (PAI-1) play essential roles in tumor invasion and metastasis. High levels of both uPA and PAI-1 are associated with poor prognosis in breast cancer patients. To confirm the prognostic value of uPA and PAI-1 in primary breast cancer, we reanalyzed individual patient data provided by members of the European Organization for Research and Treatment of Cancer-Receptor and Biomarker Group (EORTC-RBG). METHODS: The study included 18 datasets involving 8377 breast cancer patients. During follow-up (median 79 months), 35% of the patients relapsed and 27% died. Levels of uPA and PAI-1 in tumor tissue extracts were determined by different immunoassays; values were ranked within each dataset and divided by the number of patients in that dataset to produce fractional ranks that could be compared directly across datasets. Associations of ranks of uPA and PAI-1 levels with relapse-free survival (RFS) and overall survival (OS) were analyzed by Cox multivariable regression analysis stratified by dataset, including the following traditional prognostic variables: age, menopausal status, lymph node status, tumor size, histologic grade, and steroid hormone-receptor status. All P values were two-sided. RESULTS: Apart from lymph node status, high levels of uPA and PAI-1 were the strongest predictors of both poor RFS and poor OS in the analyses of all patients. Moreover, in both lymph node-positive and lymph node-negative patients, higher uPA and PAI-1 values were independently associated with poor RFS and poor OS. For (untreated) lymph node-negative patients in particular, uPA and PAI-1 included together showed strong prognostic ability (all P<.001). CONCLUSIONS: This pooled analysis of the EORTC-RBG datasets confirmed the strong and independent prognostic value of uPA and PAI-1 in primary breast cancer. For patients with lymph node-negative breast cancer, uPA and PAI-1 measurements in primary tumors may be especially useful for designing individualized treatment strategies.

Adult↗
PubMed2002

Interaction of plasminogen activator inhibitor type-1 (PAI-1) with vitronectin.

The serpin plasminogen activator inhibitor type 1 (PAI-1) plays an important role in physiological processes such as thrombolysis and fibrinolysis, as well as pathophysiological processes such as thrombosis, tumor invasion and metastasis. In addition to inhibiting serine proteases, mainly tissue-type (tPA) and urokinase-type (uPA) plasminogen activators, PAI-1 interacts with different components of the extracellular matrix, i.e. fibrin, heparin (Hep) and vitronectin (Vn). PAI-1 binding to Vn facilitates migration and invasion of tumor cells. The most important determinants of the Vn-binding site of PAI-1 appear to reside between amino acids 110-147, which includes alpha helix E (hE, amino acids 109-118). Ten different PAI-1 variants (mostly harboring modifications in hE) as well as wild-type PAI-1, the previously described PAI-1 mutant Q123K, and another serpin, PAI-2, were recombinantly produced in Escherichia coli containing a His(6) tag and purified by affinity chromatography. As shown in microtiter plate-based binding assays, surface plasmon resonance and thrombin inhibition experiments, all of the newly generated mutants which retained inhibitory activity against uPA still bound to Vn. Mutant A114-118, in which all amino-acids at positions 114-118 of PAI-1 were exchanged for alanine, displayed a reduced affinity to Vn as compared to wild-type PAI-1. Mutants lacking inhibitory activity towards uPA did not bind to Vn. Q123K, which inhibits uPA but does not bind to Vn, served as a control. In contrast to other active PAI-1 mutants, the inhibitory properties of A114-118 towards thrombin as well as uPA were significantly reduced in the presence of Hep. Our results demonstrate that the wild-type sequence of the region around hE in PAI-1 is not a prerequisite for binding to Vn.

Heparin↗
PubMed2002

uPA-silica-Particles (SP-uPA): a novel analytical system to investigate uPA-uPAR interaction and to test synthetic uPAR antagonists as potential cancer therapeutics.

The urokinase-type plasminogen activation system, including the serine protease uPA (urokinase-type plasminogen activator) and its cell surface receptor (uPAR, CD87), are important key molecules in tumor invasion and metastasis. Besides its proteolytic function, binding of uPA to uPAR on tumor cells exerts various cell responses such as migration, adhesion, proliferation, and differentiation. Hence, the uPA/uPAR system is a potential target for tumor therapy. We have designed a new generation of uPA-derived synthetic cyclic peptides suited to interfere with the binding of uPA to uPAR and present a new technology involving micro silica particles coated with uPA (SP-uPA) and reacting with recombinant soluble uPAR (suPAR), to rapidly assess the antagonistic potential of uPA-peptides by flow cytofluorometry (FACS). For this, we used silica particles of 10 microm in diameter to which HMW-uPA is coupled using the EDC/NHS method. Soluble, recombinant suPAR was added and the interaction of SP-uPA with suPAR verified by reaction with monoclonal antibody HD13.1 directed to uPAR, followed by a cyan dye (cy5)-labeled antibody directed against mouse IgG. Thereby it was possible to test naturally occurring ligands of uPAR (HMW-uPA, ATF) as well as highly effective, synthetic cyclic uPA-derived peptides (cyclo21,29[D-Cys21Cys29]-UPA21-30, cyclo21,29[D-Cys21Nle28Cys29]-uPA21-30, cyclo21,29[D-Cys(21)2-Nal24Cys29]-uPA21-30, and cyclo21,29[D-Cys21Orn23Thi24Thi25Cys29]-uPA21-30. The results obtained with the noncellular SP-uPA/uPAR system are highly comparable to those obtained with a cellular system involving FITC-uPA and the promyeloid cell line U937 as the source of uPAR.

Antibodies, Monoclonal↗
PubMed2002

Clinical utility of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 determination in primary breast cancer tissue for individualized therapy concepts.

Invasion factors urokinase-type plasminogen activator (uPA) and its plasminogen activator inhibitor (PAI-1) are the only novel tumor biological prognostic factors validated at the highest level of evidence with regard to their clinical utility in breast cancer. Antigen levels of both factors present in extracts of primary tumor tissue are determined by standardized, quality-assured enzyme-linked immunosorbent assays. Numerous studies showed that patients with low levels of uPA and PAI-1 have a significantly better survival than patients with high levels of either factor. Recently, these data have been validated by a European Organization for Research and Treatment of Cancer pooled analysis comprising more than 8000 breast cancer patients. The particular combination of both factors, uPA/PAI-1 (both low vs. either or both factors high), outperforms the single factors as well as other traditional prognostic factors with regard to risk group assessment, particularly in node-negative breast cancer. Node-negative breast cancer patients with low levels of uPA and PAI-1 have a very good prognosis and, as such, may be candidates for being spared the burden of adjuvant chemotherapy. In contrast, node-negative patients with high uPA/PAI-1 are at a substantially increased risk of relapse, comparable to that of patients with > or = 3 involved axillary lymph nodes. First results from a multicenter prospective randomized therapy trial in node-negative breast cancer (Chemo N(0)) as well as recent retrospective analyses indicate that these high-risk patients benefit from adjuvant chemotherapy. Thus, combined determination of the invasion factors uPA and PAI-1 supports risk-adapted individualized therapeutic strategies in patients with primary breast cancer, particularly in those with node-negative breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Immunofluorometric quantification of human kallikrein 5 expression in ovarian cancer cytosols and its association with unfavorable patient prognosis.

Human kallikrein 5 (hK5; encoded by the KLK5 gene) is a secreted serine protease expressed in hormonally regulated tissues, including the breast and ovary. We have previously reported regulation of the KLK5 gene by estrogens and progestins and its clinical value as a marker of poor prognosis in breast and ovarian cancers. We thus hypothesized that hK5 may represent a potential biomarker for ovarian carcinomas, at the protein level. Using a newly developed ELISA, hK5 levels were quantified (nanograms per milligram of total protein) in 22 low malignant potential (LMP) and 132 epithelial ovarian tumors and correlated with various clinicopathological variables and outcome [progression-free survival (PFS), overall survival (OS)]. hK5 concentration in LMP tumors ranged from 0 to 2.3 ng/mg (mean = 0.24) and from 0 to 220 ng/mg (mean = 3.35) in ovarian tumor cytosols (p = 0.002). Using a cutoff value of 0.15 ng/mg, 60% of ovarian tumors were categorized as hK5 positive. We found a strong correlation between patients with hK5-positive tumors and disease stages III/IV and grade 3 tumors (all p < 0.05). Univariate survival analysis revealed that hK5-positive patients had a significantly shorter PFS and OS (p < 0.05). Kaplan-Meier survival curves further confirmed an increased risk of relapse and death in women with hK5-positive tumors (p = 0.015 and p = 0.019, respectively). Multivariate analysis indicated that the prognostic value of hK5 was not independent from other parameters in the entire group of patients. When stratified by tumor grade (G1/2 vs. G3) and debulking success (optimal vs. suboptimal), univariate and multivariate analyses demonstrated that hK5 was an independent indicator of poor prognosis for patients with grade 3 tumors and with optimal debulking (p < 0.05). In patients with disease stage I/II versus III/IV, hK5 positivity was independently associated with a shorter PFS (p = 0.046) and marginally decreased OS (p = 0.08), in multivariate analysis. Lastly, we observed a fairly weak, positive, but statistically significant correlation between the expression levels of tissue hK5 and tissue CA125 (r(s) = 0.297; p < 0.001). Our findings provide evidence for an association between hK5 and more aggressive forms of epithelial ovarian cancer.

Adult↗
PubMedDate not supplied

Interaction of plasminogen activator inhibitor type-1 (PAI-1) with vitronectin (Vn): mapping the binding sites on PAI-1 and Vn.

The serpin plasminogen activator inhibitor type-1 (PAI-1), as the primary physiological inhibitor of both urokinase-type (uPA) and tissue-type (tPA) plasminogen activator, plays an important role in the regulation of the fibrinolytic system as well as in extracellular remodeling in both physiological and pathophysiological processes. In plasma as well as in the extracellular matrix PAI-1 binds to vitronectin (Vn), an interaction that affects the function of both proteins. As PAl-1/Vn interaction has a significant regulatory function in fibrinolysis, thrombolysis, and cell adhesion in cancer spread, there is a strong interest in defining the binding sites on PAI-1 and Vn as the basis of a rational design of novel drugs that may modulate PAI-1/Vn-mediated effects. In this minireview, we give an overview on the approaches to define the Vn binding site of PAI-1 and vice versa. Although in the case of PAI-1 the region around alpha-helix E and alpha-helix F of PAI-1 has been demonstrated to be important for its interaction with Vn, the precise location of the Vn-binding region has not completely been resolved. The major high-affinity PAI-1 binding region of Vn is localized within the N-terminal somatomedin B (SMB) domain of Vn. There are indications for at least one other low-affinity PAI-1 binding site in the C-terminal region of Vn, which seems to be involved in the formation of larger PAI-1/Vn complexes.

Binding Sites↗
PubMedDate not supplied

Induction of tumor cell death by high hydrostatic pressure as a novel supporting technique in orthopedic surgery.

As vegetative forms of microorganisms are impaired by high hydrostatic pressure (HHP) in the range of 400-600 MPa, the non-thermal inactivation of vegetative bacteria, yeasts, and moulds present in foods such as jams, fruit juices, and dressings by HHP is now well-established. Eukaryotic cells, when subjected to HHP are also damaged. In the present study, the effect of HHP on cell viability of human osteoblasts (HOB), human fibroblasts (HFB), and different tumor cell lines such as osteosarcoma cells SAOS-2, human histiocytic leukemia cells U-937, and the ovarian cancer cell line OV-MZ-6 was investigated. Therefore the different cell lines were subjected to pressures between 50 and 400 MPa and tested for viability. At HHP of 100 MPa (10 min) about 80% of the various cell lines were still alive. At 350 MPa all of the cells were damaged and dead. The three tumor cell lines investigated were slightly more resistant to HHP (50% dead at 170-193 MPa) than HOB and HFB (50% dead at 130-145 MPa). The present study demonstrates that both normal cells and tumor cells are rapidly inactivated by HHP treatment.

Apoptosis↗
PubMedDate not supplied

High hydrostatic pressure-induced cell death in human chondrocytes and chondrosarcoma cells.

BACKGROUND: In orthopedic surgery, sterilization of bone used for reconstruction of osteoarticular defects caused by malignant tumors is carried out in different ways. At present, to devitalize tumor-bearing osteochondral segments, extracorporal irradiation or autoclaving is mainly used, although both methods have substantial disadvantages, e.g. loss of biomechanical and/or biological integrity of the bone and destabilization of the articular surface. In this regard, high hydrostatic pressure (HHP) treatment of bone is a new, advancing technology, now being used in preclinical testing to inactivate tumor cells. To find out if this technique is also suited for extracorporal inactivation of chondrocytes and chondral tumor cells, the effect of HHP on cell viability and morphology of human chondrocytes / chondrosarcoma cells was investigated in the present study. MATERIALS AND METHODS: SW1353 chondrosarcoma cells and chondrocytes were subjected to HHP in the range of 50 to 350 MPa (10 min, 37 degrees C) and, subsequently, cell viability and cell morphology assessed. RESULTS: After exposure at 350 MPa, all HHP-treated chondral cells showed explicit morphological changes, evident by membrane ruffling and bleb formation; chondrosarcoma cells treated this way were irreversibly damaged and not alive. CONCLUSION: We anticipate that, in orthopedic surgery, HHP eventually can serve as a novel, promising technical approach for cell inactivation (including tumor cells) and allow subsequent reimplantation of the osteoarticular autograft.

Aged↗
PubMedDate not supplied

Effect of extracorporeal high hydrostatic pressure on cellular outgrowth from tumor-afflicted bone.

At present, in orthopedic surgery, the reconstruction of bone defects following resection of malignant tumors is effected by several methods. The irradiation and autoclaving of bone segments are the 2 methods of choice to extracorporeally devitalize the resected tumor-bearing bone segments. An alternative, gentle method of devitalizing bone-associated cells by exposing normal and tumor cells to extracorporeal high hydrostatic pressure (HHP) has been introduced. The aim of this study was to examine the ex vivo effect of HHP on the cell growth of normal and tumor-afflicted freshly-resected small human bone segments. For this, tumor-afflicted human bone segments of 5 x 5 x 5 mm in size, obtained during surgery from 14 patients suffering from chondrosarcoma or osteosarcoma, in comparison to bone segments obtained from 36 patients with normal bone, disease were exposed to HHP levels of 0, 150 and 300 MPa for 10 min at 37 degrees C. Following HHP-treatment, the specimens were placed into cell culture and observed for cell outgrowth up to 50 days. In control samples (0 MPa), rapid outgrowth of cells was observed. HHP-treatment of 150 MPa however, resulted in reduced outgrowth of cells from these bone specimens; at 300 MPa, no outgrowth of cells was detected. Light microscopy and standard histological examination showed morphological changes between control samples (0 MPa) and 150 MPa. Our results suggest that the treatment of tumor-afflicted bone and the associated cartilage by HHP leads to the devitalization of bone cells concomitant with complete impairment of cellular outgrowth, a precondition for re-implantation of the HHP-treated bone.

Bone Neoplasms↗