Biomedical subjects

Boban M Erovic

Publications and source records attributed to Boban M Erovic.

13 recordsLinked to original sources

PubMed2006

Effects of epidermal growth factor and keratinocyte growth factor on the growth of oropharyngeal keratinocytes in coculture with autologous fibroblasts in a three-dimensional matrix.

Tissue engineering of oropharyngeal mucosa is rendered complex by the fact that oropharyngeal keratinocytes are difficult to culture in the long term and do not grow well after several subcultivations. Three populations of oropharyngeal keratinocytes were isolated by a method based on different levels of beta(1)-integrin expression. In particular, keratinocytes were isolated between cell fractions that adhere rapidly on collagen-IV-coated culture dishes (RAC-IV) and populations that are less adherent (RAC-IV-D). The total fraction of both subpopulations served as a control (RAC-IV-T). The epidermal growth factor (EGF) and the keratinocyte growth factor (KGF) were examined with regard to their effects on the growth of the three populations. Growth curves of all three cell fractions grown with or without EGF were generated, and different concentrations of EGF and KGF were tested. EGF did not change any growth characteristics of the cells, with the exception of the speed of growth. Best growth was achieved with a physiologic EGF concentration of 0.15-1.5 ng/ml and a KGF concentration of 15 ng/ml. Finally, we cocultured oropharyngeal keratinocytes and their autologous fibroblasts in a three-dimensional matrix using Matrigeltrade mark. Oropharyngeal keratinocytes grown in coculture formed larger colonies than keratinocytes grown without fibroblasts. In conclusion, we were able to optimize the supplement of EGF and KGF in standard medium for the long-term culture of primary oropharyngeal keratinocytes. The use of Matrigel as a scaffold for three-dimensional cocultures of oropharyngeal keratinocytes and fibroblasts might signify a step forward in the development of a transplantable mucosa construct.

Biocompatible Materials↗

PubMed2005

Mcl-1, vascular endothelial growth factor-R2, and 14-3-3sigma expression might predict primary response against radiotherapy and chemotherapy in patients with locally advanced squamous cell carcinomas of the head and neck.

PURPOSE: This study was done to explore whether the expression of a selected set of proteins could predict primary response to radiotherapy or concomitant radiotherapy and chemotherapy in patients with advanced head and neck cancer. EXPERIMENTAL DESIGN: Forty-three pretreatment tumor biopsies were taken during diagnostic panendoscopy and examined for Mcl-1, vascular endothelial growth factor (VEGF)-R2, CD9, and 14-3-3sigma expression by immunohistochemistry. Forty-three patients underwent primary radiotherapy, of which, 29 patients received concomitant chemotherapy (low dose daily cisplatin, mitomycin C bolus). The primary end-point was locoregional tumor control 6 months after completion of radiotherapy. Mcl-1, VEGF-R2, CD9, and 14-3-3sigma expression were correlated with patients' primary response to radiotherapy and chemotherapy and with established clinicopathologic variables. RESULTS: Thirty complete and 13 partial responses were observed in our patient group. High expression levels of Mcl-1 (P=0.021), VEGF-R2 (P=0.032), and 14-3-3sigma (P=0.013), but not of CD9, in tumor biopsies was correlated with complete response. Overexpression of at least two of the three aforementioned proteins in pretreatment biopsies predicted-with a likelihood of 80%-whether a patient would achieve complete response to radiotherapy and chemotherapy. However, if only one of these proteins is overexpressed, there is a likelihood of 84.6% that this patient would not completely respond to therapy. CONCLUSION: Determining the expression levels of Mcl-1, VEGF-R2, and 14-3-3sigma may be helpful in predicting the early clinical response in head and neck tumor patients receiving primary radiotherapy and chemotherapy and may further allow a pretherapeutic selection of patients.

14-3-3 Proteins↗

PubMed2005

The effect of nimesulide, a selective cyclooxygenase-2 inhibitor, on Ets-1 and Ets-2 expression in head and neck cancer cell lines.

BACKGROUND: The protooncogenes Ets-1 and Ets-2 are involved in carcinogenesis of different tumors. Nimesulide, a selective cyclooxygenase-2 (COX-2) inhibitor, has antiproliferative effects on tumor cells. The question arises whether nimesulide influences Ets-1 and Ets-2 synthesis in head and neck tumors. METHODS: Expression of Ets-1 and Ets-2 was analyzed in tumor tissues by immunohistochemistry. The influence of nimesulide and an extracellular signal-regulated kinase (ERK) inhibitor on cell proliferation of two head and neck cancer cell lines and Ets-1 and Ets-2 expression was determined by automated cell counting and Western blotting, respectively. RESULTS: Immunohistochemistry showed a high expression of Ets-1 and Ets-2 in tumor tissues. In both cell lines, Ets-1 and Ets-2 expression were reduced after 24 and 48 hours by nimesulide. CONCLUSION: Both Ets-1 and Ets-2 are overexpressed in head and neck cancer specimens. Inhibition of Ets-1 and Ets-2 expression in head and neck cancer cell lines by nimesulide might explain the proapoptotic property of this COX-2 inhibitor.

Blotting, Western↗

PubMed2005

Changes in Mcl-1 expression in rectal cancer in relation to neo-adjuvant radiotherapy.

BACKGROUND: Expression of the antiapoptotic protein myeloid cell leukemia-1 (Mcl-1) may be disordered in malignancies of the rectum. High levels of Mcl-1 may correlate with unfavourable clinical outcome. AIM OF THE STUDY: The aim of the study was to determine the biologic significance and the prognostic value of the protein Mcl-1 in a group of patients with rectal cancer using immunohistochemical staining in archival specimens. PATIENTS AND METHODS: Expression of the Bcl-2 family member Mcl-1 was determined in 23 rectal malignancies. Half of the patients with rectal cancer were treated with preoperative short-term radiation therapy of 25 Gy followed by radical surgery; the other patients were treated just with radical surgery. Differences in Mcl-1 expression between irradiated and non-irradiated rectal cancer cells were analysed immunohistochemically, and Mcl-1 expression was correlated with overall survival. Induction of Mcl-1 expression by irradiation versus control in colorectal cancer cells was detected using Western blot. RESULTS: Mcl-1 was expressed at high levels in 35% of all specimens. Significantly stronger expression was detected in specimens of irradiated rectal cancer compared with non-irradiated tissues (p-value: 0.005). No association was seen between marker expression patterns and clinicopathological data of the respective patients. CONCLUSION: Our findings indicate that irradiated rectal cancer produces significantly higher levels of the antiapoptotic protein Mcl-1 than non-irradiated rectal carcinoma. The data also suggest that the high level of Mcl-1 was induced by the radiotherapy. As Mcl-1 is an antiapoptotic regulator, its over-expression in irradiated rectal cancer could constitute a detrimental development antagonizing the potential benefit of adjuvant radiotherapy. Further evaluation of the correlation between Mcl-1 expression and overall survival seems warranted.

Adenocarcinoma↗

PubMed2005

Quantitation of microvessel density in squamous cell carcinoma of the head and neck by computer-aided image analysis.

OBJECTIVE: Angiogenesis is the formation of new blood vessels from a preexisting vascular network. In healthy individuals it is normally suppressed and observed only transiently during development, reproduction and wound healing. However, growth, invasion, and metastasis of most solid tumors are dependent on angiogenesis. Without formation of new blood vessels, also termed as neovascularization, tumors cannot exceed a size of about 1 mm3. Therefore, neovascularization is a basic requirement for nutrition and oxygenation of tumor cells. Numerous studies in different solid as well as non-solid tumors have evaluated the prognostic value of tumor neovascularization. In solid tumors the increased microvessel density, the pathological correlate to tumor neovascularization, has been linked to a worse prognosis of the disease. The aim of the current study was to assess the prognostic value of tumor neovascularization for recurrences in squamous cell carcinoma of the head and neck by determining microvessel density. Data was collected using an automated-computerized method and as well as a manual counting method. BASIC RESEARCH DESIGN: Immunohistochemistry was performed to detect intratumoral microvessels in tumor samples of 50 patients with squamous cell carcinoma of the head and neck. We used a monoclonal mouse antibody directed against the CD34 antigen. After immunostaining, the entire tumor section was scanned microscopically at low power (x 40) to identify hot spots, which are the areas of highest neovascularization. Individual tumor microvessels were then counted under high power (x 200) to obtain a vessel count in a defined area, and the average vessel count in 4 hot spots was taken as the microvessel density. Microvessel counting was performed twice by computerized method, as well as manually by two independent investigators without any previous knowledge of patients' pertinent clinical data. Subsequently, both counting techniques were statistically compared with each other. RESULTS: On computer-aided image analysis an increased microvessel density was significantly correlated with recurrence of disease (p = 0.02). Repetitive computer counts yielded similar results (p = 0.08), whereas repeated manual counts by two investigators varied significantly (p = 0.04). However, no further statistical correlations between microvessel density and patients clinical data i.e. tumor status, lymph node status, overall survival, or disease free interval could be found. Furthermore, estimation of overall survival of patients with an increased microvessel density by Kaplan-Meier curves revealed non-significant results. CONCLUSION: There is mounting evidence that suggests, that assessment of tumor neovascularization might provide a novel approach of prognostication in patients with squamous cell carcinomas of the head and neck. In particular, in the present study, the degree of angiogenesis of a tumor, as assessed by microvessel density, was found to be correlated with recurrent disease in squamous cell carcinoma of the head and neck. Computer aided image analysis, an automated technique, constitutes a time-efficient and reproducible technique for quantification of tumor vascularization. We suggest that this computerized microvessel determination could be used as a reliable method for microvessel counts, which, furthermore, seems to be superior to manual counting. However, for a reliable and reproducible assessment of tumor neovascularization, validation procedures and quality control protocols are mandatory.

Adult↗

PubMed2005

Expression levels of Akt in nimesulide-treated squamous carcinoma cell lines of the head and neck.

Nimesulide, a selective cyclooxygenase-2 (COX-2) inhibitor, is known to induce apoptosis in various cell lines. So far, the molecular targets that account for this effect are unknown. Akt and extracellular-signal regulated kinase (ERK) are both important signaling molecules, which promote survival in different types of cancer, including head and neck cancer. The aim of our study was to describe the effect of treatment with nimesulide and ERK inhibitor PD 98059 on the expression patterns of Akt within the head and neck cancer cell lines SCC 9 and SCC 25. SCC 9 and SCC 25 cells were cultured in RPMI and treated with nimesulide and PD 98059. Protein expression levels were semi-quantified by Western blot analysis. Apoptosis was examined using the M30 antibody that binds to a caspase cleaved cytoskeletal protein for detection of early apoptosis in immunofluorescence studies. In both cell lines, nimesulide treatment induced apoptosis and resulted in a decrease of Akt expression. ERK inhibition had no effect on Akt expression, and combined application of both agents had the same effect as treatment with nimesulide alone. In conclusion, nimesulide induces apoptosis and promotes down-regulation of Akt-expression in squamous cell carcinoma cells, independently of ERK activity.

Antineoplastic Agents↗

PubMed2005

Combination of betulinic acid with cisplatin--different cytotoxic effects in two head and neck cancer cell lines.

Betulinic acid (BetA), a new experimental cytotoxic compound that is active against human melanoma cells and neuroectodermal tumor cells, has recently been shown to be also effective against head and neck squamous carcinoma cells (HNSCC). In this study we investigated BetA in combination with cisplatin in squamous cell carcinoma cell lines of the tongue. SCC25 and SCC9 were treated with BetA and/or cisplatin. Cells were counted with an automated analyzing system. Caspase activation was determined using the M30 Cyto-Death ELISA, expression of the anti-apoptotic protein Mcl-1 by Western blot analysis. Visualization of apoptotic cells was achieved by immunohistochemistry. Synergistic cytotoxic effect and the induction of apoptosis under combined treatment was observed in SCC25 cells only after 24 or 48 h, whereas treatment of SCC25 cells for 72 h with BetA and cisplatin showed antagonism or subadditive effects. In SCC9 cells, antagonism occurred over an increase of dose and time during treatment. Furthermore, we could not demonstrate a significant alteration in the expression of the anti-apoptotic protein, Mcl-1. Our in vitro data demonstrate that BetA seems to be an unlikely candidate for combination with cisplatin in the treatment of head and neck cancer.

Antineoplastic Agents↗

PubMed2005

Inhibition of cytotoxicity of cisplatin by cyclooxygenase-2 inhibitor nimesulide in head and neck cancer cell lines.

Although head and neck cancer is a common malignancy, investigations have not yet improved the poor prognosis of patients. Therefore, it is important to find new cancer treatment modalities. Recent studies showed that cyclooxygenase, especially its isoform cyclooxygenase-2, is involved in tumorigenesis, tumor growth and metastasis. Inhibition of this enzyme by cyclooxygenase inhibitors has been shown to be antiproliferative in numerous cancer cell lines. The aim of this study was to investigate if the selective cyclooxygenase-2 inhibitor nimesulide could enhance cytotoxicity of the standard chemotherapeutic agent cisplatin. Head and neck squamous cell cancer cells were incubated with nimesulide and/or cisplatin, and counted after 24, 48 and 72 h treatment. Visualization of apoptotic cells was done by immunohistochemistry. We demonstrated that nimesulide inhibits the cytotoxic effect of cisplatin in HNSCC cells. Therefore, COX-2 inhibitor nimesulide may not be a good partner for cisplatin in combination therapy for cancer.

Antineoplastic Agents↗

PubMed2004

CD9 expression is not a prognostic factor in human osteosarcoma.

CD 9, also known as Motility-Related Protein-1 (MRP-1), is a member of the transmembrane four superfamily and plays a crucial role in cell adhesion, motility and signalling events. Downregulation of CD 9 has been reported to be associated with tumour progression, metastasis and clinical outcome in various kinds of solid tumours. Although prognosis of osteosarcoma has been improved by chemotherapy during the last decades, the problem of non-responders remains. At the present time prognostic factors at diagnosis have not been clearly identified. Furthermore, there is a need for markers that predict the response to chemotherapy at the time of biopsy, allowing stratification of osteosarcoma patients. In this study we investigated the effect of CD9 expression on the response to chemotherapy and survival in osteosarcoma. The expression of CD9 was examined immunohistochemically in 52 patients with high grade osteosarcoma and the results were correlated with histologic response to chemotherapy, 5 year disease free and 5 year overall survival. In patients with osteosarcoma 22 of 52 cases (42%) were positive for CD 9 expression, the rest were negative. CD 9 expression status showed no statistically significant correlation with response to chemotherapy; 41% had a poor response and 59% a good response in the CD9 positive group. In the CD9 negative group 57% had a good and 47% had a bad response. No significant difference was found when comparing disease free survival (58.9% in CD9 positive- versus 69.3% in CD9 negative tumours; P = 0.99) and overall survival of patients (54.0% in CD9 positive- versus 58.1% in CD9 negative tumours; P = 0.90) with CD9 expressing tumours to those with reduced CD9 expression. In conclusion our findings suggest that in contrast to solid tumours, CD9 is unlikely to provide any additional prognostic information for clinical purposes in osteosarcoma patients.

Adult↗

PubMed2003

Motility-related protein-1/CD9 expression in head and neck squamous cell carcinoma.

INTRODUCTION: Motility-related protein (MRP)-1/CD9 is implicated in cell adhesion and motility and was shown to be clearly involved in tumor prognosis and angiogenesis. Elevated MRP-1/CD9 expression on tumor cells has been linked to a favorable prognosis in breast cancer, colon cancer, lung cancer, and HNSCC. Because MRP-1/CD9 is associated with angiogenesis, it might play a role in tumor angiogenesis as well. METHODS: We analyzed MRP-1/CD9 expression in HNSCC specimens and cell lines by real-time RT-PCR and in HNSCC biopsy specimens and stromal vessels by immunohistochemistry. Kruskal Wallis and Chi2 test, univariate and multivariate Cox regression, and Kaplan-Meier methods were used for statistical analysis. RESULTS: Real-time and PCR RT showed elevated expression of MRP-1/CD9 in one (SCC25) of four HNSCC cell lines and two of six HNSCC patients, whereas two cell lines (SCC9 and JPPA) and one HNSCC patient had lower MRP-1/CD9 levels compared with other specimens. Immunohistochemistry demonstrated strong MRP-1/CD9 IR expression on tumor cells in 13 patients (39%), whereas 21 patients (61%) had less to medium MRP-1/CD9 IR expression. Increased MRP-1/CD9 expression on tumor cells was correlated with prolonged patient survival (p =.02) and a longer disease-free interval (p =.004), a diminished recurrence rate (p =.02), and lower stages of neck lymph nodes (p =.04). MRP-1/CD9 IR was also found in a subpopulation of vessels that seem to be less in tumor specimens than in normal mucosa (p <.0001). MRP-1/CD9+ vessels are podoplanin+ and are therefore regarded as lymphatic vessels. CONCLUSIONS: Our results revealed that elevated MRP-1/CD9 expression on HNSCC is linked to a favorable clinical outcome and confirmed reports of MRP-1/CD9 expression in other carcinomas. MRP-1/CD9+ vessels were found to be lymphatic in nature. The number and staining intensity of these vessels is decreased in tumor tissue, which suggests a stabilizing role for this protein in lymphangiogenesis.

Adult↗

PubMed2003

Pharmacodynamics of piperacillin in severely ill patients evaluated by using a PK/PD model.

Penetration of antiinfective drugs into soft tissues is essential for antimicrobial killing at the target site, but is substantially lower in severely ill patients compared with healthy subjects. The present study was conducted to assess the antimicrobial effect of piperacillin in severely ill patients. Strains of Staphylococcus aureus and Pseudomonas aeruginosa were exposed in vitro to concentrations of piperacillin, simulating the pharmacokinetic profiles measured in soft tissue of patients and healthy subjects. The simulation for patients resulted in effective killing, whereas bacterial regrowth was detected for healthy subjects. Our in vitro simulation showed that bacterial killing may be effective in severely ill patients despite relatively low concentrations of piperacillin at the target site. This finding is due to impaired renal function and subsequently prolonged tissue and plasma half-lives of piperacillin in intensive care patients.

Colony Count, Microbial↗

PubMed2003

Differential expression pattern of cyclooxygenase-1 and -2 in head and neck squamous cell carcinoma.

OBJECTIVE: The enzyme cyclooxygenase catalyzes the first step of the synthesis of prostanoids Cyclooxygenase has been shown to exist in two distinct isoforms: cyclooxygenase-1 is constitutively expressed as a housekeeping enzyme in most tissues whereas the inducible cyclooxygenase-2 has been reported to be involved in inflammatory processes and in the carcinogenesis of squamous cell carcinoma. The aim of this study was to investigate the distribution patterns of cyclooxygenase-1 and -2 in peritumoral lymphocytic infiltrates and tumor cells of head and neck carcinoma. MATERIAL AND METHODS: Immunohistochemical analysis was performed using paraffin-embedded tumor specimens from 24 patients suffering from oropharyngeal, hypopharyngeal and oral squamous cell carcinomas. RESULTS: We observed that cyclooxygenase-2 immunoreactivity, compared to that of cyclooxygenase-1, was significantly increased in peritumoral lymphocytic infiltrates as well as in tumor cells. CONCLUSION: The expression of cyclooxygenase-2 in both tumor specimens and the surrounding peritumoral lymphocytic infiltrates supports the hypothesis that cyclooxygenase may be one of several important links between chronic inflammation and carcinogenesis.

Carcinoma, Squamous Cell↗

PubMed2003

CD9 expression on lymphatic vessels in head and neck mucosa.

CD9, a member of the transmembrane 4 superfamily, is involved in cell adhesion, migration, and tumor metastasis. Little is known about its vascular expression pattern. In this study, we investigated CD9 expression on endothelial cells in the mucosa of the head and neck and compared it with vascular tumors. Using immunohistochemistry, expression of CD9 was studied in 17 samples of head and neck mucosa and skin (laryngeal mucosa: n = 2, oral: n = 6, and epidermis: n = 9) and a variety of vascular tumors (lymphangiomas: n = 9, juvenile nasopharyngeal angiofibromas: n = 4, hemangiomas: n = 7, angiosarcomas: n = 5, and Kaposi's sarcomas: n = 7) and compared with the expression of CD34 and PAL-E (blood vessel markers) and the lymphatic marker podoplanin. Regular lymphatic endothelium and lymphangiomas were strongly positive for CD9 and podoplanin but were mostly negative for PAL-E and CD34. By contrast, blood vessel endothelium and hemangiomas were strongly positive for PAL-E and CD34 but were mostly negative for CD9 and podoplanin. Weak to moderate CD9 reactivity was also observed on EC of juvenile nasopharyngeal angiofibromas, angiosarcomas, and Kaposi's sarcomas. Expression of CD9 by lymphatic EC was confirmed by reverse-transcriptase PCR and Western blot analyses. CD9 may be useful as a marker for lymphatic EC. It could promote the adherence of inflammatory and tumor cells to lymphatic EC and participate in the growth and maintenance of the lymphatic capillary net.

Antibodies, Monoclonal↗