I. Fichtner - Academia.edu (original) (raw)

Papers by I. Fichtner

European Journal of Cancer

European Journal of Cancer Supplements, 2009

Background: Cyclooxygenase-2 (COX-2)-expression may be predictive for the effect of celecoxib in ... more Background: Cyclooxygenase-2 (COX-2)-expression may be predictive for the effect of celecoxib in patients with advanced non-small cell lung cancer (NSCLC). In previous studies, COX-2-expression has almost exclusively been evaluated with immunohistochemical methods performed on histology sections of tissue biopsies. However, in clinical practice, lung cancer is often diagnosed with cytological techniques only. Methodology and results from analysis of COX-2-expression in cytological material from lung cancer patients by immunocytochemistry have, to our knowledge, not been described previously. Material and Methods: Fifty-three patients with lung cancer were prospectively examined. Material was obtained from routine diagnostic transbronchial fine-needle aspirations or transthoracic needle aspiration. Slides with obvious tumour cells were selected, fixed in 4% paraformaldehyde and immunostained with monoclonal antibody mouse-anti-human COX-2. An experienced cytopathologist evaluated the slides as well as routinely stained parallel slides. Percentage stained tumour cells (<1%, 1−10%, 11−50%, >50%) and intensity of staining (none, weak, strong) were estimated. Clinical data were collected from patient records. Results: There were 32 men and 21 women with median age 68 years (range 43−87). Eighty-nine percent had NSCLC. Preparation and staining with the methods established at our laboratory were easy to perform. Quality and readability of the slides were generally good. Tumour cells, singly and in clusters, were easily discriminated from benign cells. The percentage COX-2-stained cells and the intensity of staining varied widely between and within the different cases. The proportion of positively stained tumour cells was as follows: <1%: 20 pts., 1−10%: 7 pts., 11−50%: 17 pts., more than 50%: 9 pts. In 17 cases, groups of cells with different intensity of COX-2-staining were found in the same slide. There were no significant differences in survival when grouping the cases according to percentage of COX-2-expression. Conclusions: Immunocytochemical analysis of COX-2-expression is technically easy to perform with routine diagnostic procedures resulting in easily readable, high quality slides. There is a great variation in the proportion of COX-2-positive cells from case to case as well as in the intensity of staining between individual cells in many single cases.

European Journal of Cancer and Clinical Oncology, 1991

European Journal of Cancer

The Laboratory Research Division (LRD) of the EORTC currently consists of five Groups with expert... more The Laboratory Research Division (LRD) of the EORTC currently consists of five Groups with expertise that includes pre-clinical drug development, all aspects of cancer pharmacology, clinically-relevant receptor and biomarker studies, functional imaging and contemporary pathology. The LRD provides a Europewide resource for cancer clinical trials with particular expertise in the evolving field of translational research. In the development of therapies designed to exploit the molecular and cellular pathology of cancer, it is essential that translational research is included at all stages and the EORTC, through the LRD, has access to such expertise. In addition to providing support for drug development and clinical trials, the LRD represents a unique forum for the development of contemporary translational research expertise, the establishment of quality standards and the education of young laboratory and clinical scientists embarking on careers in oncology.

European Journal of Cancer, 2014

Nanotechnology

Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aq... more Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO–PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO–PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (−33 mV). As a prerequisite for in vivo testing, the PEO–PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO–PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and 111In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist®) as a reference nanoscaled MRI co...

British Journal of Cancer, 1996

Incidence and mortality of human malignant melanoma has risen rapidly over recent decades. Althou... more Incidence and mortality of human malignant melanoma has risen rapidly over recent decades. Although the notorious resistance to treatment is characteristic for metastatic malignant melanoma, only a few experimental models have been established to study the metastatic cascade or to test new alternative treatment modalities. Thus, new human models are wanted. Here, we describe the metastatic behaviour of seven human melanoma cell lines derived from two primary cutaneous melanomas (WM 98-1, WM 1341) and five metastases established from liver (UKRV-Mel-4), skin (M7, M13), pleural effusion (UKRV-Mel-2) and lymph node (MV3). All cell lines were analysed for their capacity to grow in nude mice after s.c. and i.v. administration. M13 cells developed liver metastases spontaneously after s.c. injection, and subsequent passages of M13 and M7 melanoma cells caused liver metastases after i.v. injection, whereas MV3 and WM98-1 gave rise to lung metastases, using the same inoculation route. In contrast, WM 1341, UKRV-Mel-2 and UKRV-Mel-4 grew only very slowly in nude mice after s.c. injection and did not cause any metastases after i.v. or s.c. administration. The pattern of metastases or growth kinetics did not correlate with the interleukin 8 or tumour necrosis factor secretion of cell lines. Adhesion molecules and growth factor receptor expression on the cell lines differed widely, as determined by flow cytometry, with the low metastatic cell lines (UKRV-Mel-2, UKRV-Mel-4 and WM 1341) demonstrating a marked reduction in VLA-1 and VLA-5 expression compared with the metastatic lines (M7, M13, MV3 and WM 98-1). Expression of pigment-related proteins such as tyrosinase, TRP-1, TRP-2, Melan-A/MART-1, gplOO, MAGEI or MAGE-3 was not associated with growth and metastatic characteristics of the melanoma cell lines analysed. In conclusion, the established human melanoma cell lines exhibited diverse growth behaviour in nude mice in congruence with some early established prognostic markers such as VLA-1 and VLA-5. The xenografts provide good models for further study of metastatic processes as well as for evaluation of alternative treatment modalities including new pharmaceutical drugs and gene therapeutic targeting using tissue-specific gene regulatory elements for gene targeting.

European Journal of Cancer Supplements, 2010

Oncogenesis, 2015

We have previously described novel histone acetyltransferase (HAT) inhibitors that block neurobla... more We have previously described novel histone acetyltransferase (HAT) inhibitors that block neuroblastoma cell growth in vitro. Here we show that two selected pyridoisothiazolone HAT inhibitors, PU139 and PU141, induce cellular histone hypoacetylation and inhibit growth of several neoplastic cell lines originating from different tissues. Broader in vitro selectivity profiling shows that PU139 blocks the HATs Gcn5, p300/CBP-associated factor (PCAF), CREB (cAMP response element-binding) protein (CBP) and p300, whereas PU141 is selective toward CBP and p300. The pan-inhibitor PU139 triggers caspase-independent cell death in cell culture. Both inhibitors block growth of SK-N-SH neuroblastoma xenografts in mice and the PU139 was shown to synergize with doxorubicin in vivo. The latter also reduces histone lysine acetylation in vivo at concentrations that block neoplastic xenograft growth. This is one of the very few reports on hypoacetylating agents with in vivo anticancer activity.

Journal of stem cells & regenerative medicine, 2007

Gene Therapy of Cancer, 2009

The main challenges for application of gene therapy to patients are poor selectivity in vector ta... more The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, jet-injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The jet-injection technology is based on jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The jet-injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of jet-injection gene transfer have recently been investigated in a phase I clinical trial.

Anticancer research

A new series of imidazothioxanthones has recently been synthesized as potential anticancer agents... more A new series of imidazothioxanthones has recently been synthesized as potential anticancer agents with the aim of overcoming drug resistance. The route of synthesis and DNA-binding properties of the compounds were reported previously. This paper describes the general structure-activity relationships for the class of imidazothioxanthones in panels of human and murine tumor cell lines in vitro, and the in vivo activity against human and murine solid tumors of the most potent compound, N-[3-(Dimethylamino)propylo]-11-oxo-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide (10a). In addition, the interaction between compound 10a and DNA is also considered in terms of molecular mechanics methods and flexible docking techniques. The cytotoxicity of compounds 10a, 11-oxo-N-[2-(pyrrolidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide, 11-oxo-N-[2-(piperidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carbo...

Haematologica, 2001

The aim of this study was the development of a fast and reliable polymerase chain reaction (PCR) ... more The aim of this study was the development of a fast and reliable polymerase chain reaction (PCR) assay which quantifies the proportion of human cells in immunodeficient chimeric mice, for example transplanted with human hematopoietic stem cells. We developed a TaqMan chemistry-based, real-time duplex PCR assay to quantify human and murine DNA in a single-tube reaction in parallel (HUmu PCR). Two independent sets of primers and exonuclease probes, located in the tumor necrosis factor-a gene of both species, were selected to amplify specifically human and murine genomic DNA. Serial dilutions of defined numbers of human cells in mouse cells served to construct calibration curves. The test was applied to NOD/SCID mice transplanted with CD34(+) cells isolated from human cord blood and compared to FACS analysis. Analysis of DNA from human cells diluted stepwise into a fixed number of murine cells - and vice versa - led to calibration curves with good correlation for human and murine cells...

Clinical cancer research : an official journal of the American Association for Cancer Research, 1999

We have established new human sarcoma lines and examined their sensitivity to common antitumor dr... more We have established new human sarcoma lines and examined their sensitivity to common antitumor drugs and expression of putative multidrug resistance (MDR) proteins. Eighty-two sarcoma samples were transplanted in nude mice. Fourteen of these sarcomas were established as tumor cell lines. We determined a chemosensitivity profile to antitumor drugs (MDR drugs = doxorubicin, mitoxantrone, and vincristine; non-MDR drugs = cisplatin, ifosfamide, and bleomycin) for each tumor line in vivo. Response to chemotherapy with doxorubicin and ifosfamide was observed in 30-50% of these tumor lines. Our results obtained with xenotransplants are similar to the results documented in clinical trials in which doxorubicin and ifosfamide are effective in 30-50% of the patients. Furthermore, we examined expression of MDR-relevant markers like P-glycoprotein, MDR-associated protein, lung resistance protein, and mdr1 mRNA in these xenotransplants. A relationship between mdr1 mRNA expression and response to ...

Advances in experimental medicine and biology, 1998

Anticancer research

Standard CD44 (CD44s) and variant isoforms (CD44v) are expressed on different malignant cells and... more Standard CD44 (CD44s) and variant isoforms (CD44v) are expressed on different malignant cells and tissues. Their upregulation has been implicated, in the progression and metastasis of malignomas. In this work we addressed the question of whether these molecules are also expressed on xenografted human breast carcinomas and if certain expression patterns are correlated with biological parameters like tumour size, hormone receptor status, histology, growth rate, chemoresistance and microenvironment. Additionally, we were interested in the shedding of soluble CD44 (sCD44) into the blood circulation of tumour bearing nude mice. The human breast carcinomas MCF-7, MCF-7/ADR, 4296 and MDA-MB435, 4134 and 4151 were transplanted subcutaneously (sc.) or into the mammary fat pad (mfp.) of nude mice. The expression of the CD44s, -v6, and -v9 isoforms was determined at different time points on tissue samples by immunohistochemistry or RT-PCR employing human-specific antibodies or primers, respect...

Bone marrow transplantation, 1996

Peripheral blood progenitor cells (PBPCs) obtained from cytapheresis products (CPs) of tumor pati... more Peripheral blood progenitor cells (PBPCs) obtained from cytapheresis products (CPs) of tumor patients undergoing mobilizing chemotherapy for PBPC support and dose-intensified anticancer chemotherapy initiate multilineage human hematopoiesis after intraperitoneal (i.p.) transplantation into young severe combined immunodeficient (SCID) mice. The engraftment process was significantly accelerated by subcutaneous cotransplants of a rat fibroblast cell line stably transfected with a retroviral vector carrying the human interleukin-3 (hIL-3) gene and producing sustained in vivo levels of circulating human IL-3 over a prolonged period of time. These cotransplants were found to provide a suitable microenvironment for i.p. transplanted CD34-positive cells separated from PBPC preparations using immunomagnetic beads. Flow cytometry analysis and immunocytology revealed that selected PB CD34- cells, more than 90% pure, were capable of initiating and sustaining a productive multilineage hematopoie...

Anticancer research

This paper reports studies on P388 leukemic cells sensitive and resistant to ADR and VCR. The P45... more This paper reports studies on P388 leukemic cells sensitive and resistant to ADR and VCR. The P450 dependent enzyme system and the cytosolic calcium were estimated and are discussed in relation to MDR. It could be shown, in comparison to sensitive P388 cells, that the plasma membrane permeability for fluorescent dyes like rhodamine 123 and fura-2 and the biotransformation of xenobiotics are changed in resistant cells. Whereas the transport behaviour for the dyes is similarly induced in resistant cells independent of the drug which made the MDR, the P450 dependent enzyme activities are strongly increased in P388/ADR in comparison to the P388 and P388/VCR. The cell cycle analysis shows the same effect. Many more cells of P388/ADR are in the S-phase in comparison to P388 or P388/VCR. The LI is also increased in this direction. Therefore, it can be concluded that, depending on the kind of drug which made the MDR, different biochemical mechanisms are activated.

Anticancer research

It was the aim of this study to compare drug-resistant sublines of the murine P388 in relation to... more It was the aim of this study to compare drug-resistant sublines of the murine P388 in relation to resistance markers, the resistant phenotype and immunogenicity. Resistance to drugs either belonging to the MDR type (Doxorubicin, Vincristine, Mitoxantrone) or to the non-MDR type (Methotrexate) was generated in vivo in order to mimic the clinical situation. All resistant sublines expressed the mdr1 gene and the p-glycoprotein determined on m-RNA level or immunohistochemically, while no expression was registered in the parent P388. The rhodamine 123 fluorescence as marker for the energy dependent drug efflux pump was decreased only in the MDR-sublines, while the parent P388 and the Methotrexate-resistant line retained 100% or 90% of the dye, respectively. This indicates that the rhodamine efflux is a more function-related marker for MDR than the mdr1 gene and the pgp. The in vivo characterization of the sublines as regards their sensitivity to cytostatics revealed a clear-cut cross-res...

European Journal of Cancer

European Journal of Cancer Supplements, 2009

Background: Cyclooxygenase-2 (COX-2)-expression may be predictive for the effect of celecoxib in ... more Background: Cyclooxygenase-2 (COX-2)-expression may be predictive for the effect of celecoxib in patients with advanced non-small cell lung cancer (NSCLC). In previous studies, COX-2-expression has almost exclusively been evaluated with immunohistochemical methods performed on histology sections of tissue biopsies. However, in clinical practice, lung cancer is often diagnosed with cytological techniques only. Methodology and results from analysis of COX-2-expression in cytological material from lung cancer patients by immunocytochemistry have, to our knowledge, not been described previously. Material and Methods: Fifty-three patients with lung cancer were prospectively examined. Material was obtained from routine diagnostic transbronchial fine-needle aspirations or transthoracic needle aspiration. Slides with obvious tumour cells were selected, fixed in 4% paraformaldehyde and immunostained with monoclonal antibody mouse-anti-human COX-2. An experienced cytopathologist evaluated the slides as well as routinely stained parallel slides. Percentage stained tumour cells (<1%, 1−10%, 11−50%, >50%) and intensity of staining (none, weak, strong) were estimated. Clinical data were collected from patient records. Results: There were 32 men and 21 women with median age 68 years (range 43−87). Eighty-nine percent had NSCLC. Preparation and staining with the methods established at our laboratory were easy to perform. Quality and readability of the slides were generally good. Tumour cells, singly and in clusters, were easily discriminated from benign cells. The percentage COX-2-stained cells and the intensity of staining varied widely between and within the different cases. The proportion of positively stained tumour cells was as follows: <1%: 20 pts., 1−10%: 7 pts., 11−50%: 17 pts., more than 50%: 9 pts. In 17 cases, groups of cells with different intensity of COX-2-staining were found in the same slide. There were no significant differences in survival when grouping the cases according to percentage of COX-2-expression. Conclusions: Immunocytochemical analysis of COX-2-expression is technically easy to perform with routine diagnostic procedures resulting in easily readable, high quality slides. There is a great variation in the proportion of COX-2-positive cells from case to case as well as in the intensity of staining between individual cells in many single cases.

European Journal of Cancer and Clinical Oncology, 1991

European Journal of Cancer

The Laboratory Research Division (LRD) of the EORTC currently consists of five Groups with expert... more The Laboratory Research Division (LRD) of the EORTC currently consists of five Groups with expertise that includes pre-clinical drug development, all aspects of cancer pharmacology, clinically-relevant receptor and biomarker studies, functional imaging and contemporary pathology. The LRD provides a Europewide resource for cancer clinical trials with particular expertise in the evolving field of translational research. In the development of therapies designed to exploit the molecular and cellular pathology of cancer, it is essential that translational research is included at all stages and the EORTC, through the LRD, has access to such expertise. In addition to providing support for drug development and clinical trials, the LRD represents a unique forum for the development of contemporary translational research expertise, the establishment of quality standards and the education of young laboratory and clinical scientists embarking on careers in oncology.

European Journal of Cancer, 2014

Nanotechnology

Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aq... more Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO–PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO–PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (−33 mV). As a prerequisite for in vivo testing, the PEO–PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO–PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and 111In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist®) as a reference nanoscaled MRI co...

British Journal of Cancer, 1996

Incidence and mortality of human malignant melanoma has risen rapidly over recent decades. Althou... more Incidence and mortality of human malignant melanoma has risen rapidly over recent decades. Although the notorious resistance to treatment is characteristic for metastatic malignant melanoma, only a few experimental models have been established to study the metastatic cascade or to test new alternative treatment modalities. Thus, new human models are wanted. Here, we describe the metastatic behaviour of seven human melanoma cell lines derived from two primary cutaneous melanomas (WM 98-1, WM 1341) and five metastases established from liver (UKRV-Mel-4), skin (M7, M13), pleural effusion (UKRV-Mel-2) and lymph node (MV3). All cell lines were analysed for their capacity to grow in nude mice after s.c. and i.v. administration. M13 cells developed liver metastases spontaneously after s.c. injection, and subsequent passages of M13 and M7 melanoma cells caused liver metastases after i.v. injection, whereas MV3 and WM98-1 gave rise to lung metastases, using the same inoculation route. In contrast, WM 1341, UKRV-Mel-2 and UKRV-Mel-4 grew only very slowly in nude mice after s.c. injection and did not cause any metastases after i.v. or s.c. administration. The pattern of metastases or growth kinetics did not correlate with the interleukin 8 or tumour necrosis factor secretion of cell lines. Adhesion molecules and growth factor receptor expression on the cell lines differed widely, as determined by flow cytometry, with the low metastatic cell lines (UKRV-Mel-2, UKRV-Mel-4 and WM 1341) demonstrating a marked reduction in VLA-1 and VLA-5 expression compared with the metastatic lines (M7, M13, MV3 and WM 98-1). Expression of pigment-related proteins such as tyrosinase, TRP-1, TRP-2, Melan-A/MART-1, gplOO, MAGEI or MAGE-3 was not associated with growth and metastatic characteristics of the melanoma cell lines analysed. In conclusion, the established human melanoma cell lines exhibited diverse growth behaviour in nude mice in congruence with some early established prognostic markers such as VLA-1 and VLA-5. The xenografts provide good models for further study of metastatic processes as well as for evaluation of alternative treatment modalities including new pharmaceutical drugs and gene therapeutic targeting using tissue-specific gene regulatory elements for gene targeting.

European Journal of Cancer Supplements, 2010

Oncogenesis, 2015

We have previously described novel histone acetyltransferase (HAT) inhibitors that block neurobla... more We have previously described novel histone acetyltransferase (HAT) inhibitors that block neuroblastoma cell growth in vitro. Here we show that two selected pyridoisothiazolone HAT inhibitors, PU139 and PU141, induce cellular histone hypoacetylation and inhibit growth of several neoplastic cell lines originating from different tissues. Broader in vitro selectivity profiling shows that PU139 blocks the HATs Gcn5, p300/CBP-associated factor (PCAF), CREB (cAMP response element-binding) protein (CBP) and p300, whereas PU141 is selective toward CBP and p300. The pan-inhibitor PU139 triggers caspase-independent cell death in cell culture. Both inhibitors block growth of SK-N-SH neuroblastoma xenografts in mice and the PU139 was shown to synergize with doxorubicin in vivo. The latter also reduces histone lysine acetylation in vivo at concentrations that block neoplastic xenograft growth. This is one of the very few reports on hypoacetylating agents with in vivo anticancer activity.

Journal of stem cells & regenerative medicine, 2007

Gene Therapy of Cancer, 2009

The main challenges for application of gene therapy to patients are poor selectivity in vector ta... more The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, jet-injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The jet-injection technology is based on jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The jet-injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of jet-injection gene transfer have recently been investigated in a phase I clinical trial.

Anticancer research

A new series of imidazothioxanthones has recently been synthesized as potential anticancer agents... more A new series of imidazothioxanthones has recently been synthesized as potential anticancer agents with the aim of overcoming drug resistance. The route of synthesis and DNA-binding properties of the compounds were reported previously. This paper describes the general structure-activity relationships for the class of imidazothioxanthones in panels of human and murine tumor cell lines in vitro, and the in vivo activity against human and murine solid tumors of the most potent compound, N-[3-(Dimethylamino)propylo]-11-oxo-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide (10a). In addition, the interaction between compound 10a and DNA is also considered in terms of molecular mechanics methods and flexible docking techniques. The cytotoxicity of compounds 10a, 11-oxo-N-[2-(pyrrolidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide, 11-oxo-N-[2-(piperidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carbo...

Haematologica, 2001

The aim of this study was the development of a fast and reliable polymerase chain reaction (PCR) ... more The aim of this study was the development of a fast and reliable polymerase chain reaction (PCR) assay which quantifies the proportion of human cells in immunodeficient chimeric mice, for example transplanted with human hematopoietic stem cells. We developed a TaqMan chemistry-based, real-time duplex PCR assay to quantify human and murine DNA in a single-tube reaction in parallel (HUmu PCR). Two independent sets of primers and exonuclease probes, located in the tumor necrosis factor-a gene of both species, were selected to amplify specifically human and murine genomic DNA. Serial dilutions of defined numbers of human cells in mouse cells served to construct calibration curves. The test was applied to NOD/SCID mice transplanted with CD34(+) cells isolated from human cord blood and compared to FACS analysis. Analysis of DNA from human cells diluted stepwise into a fixed number of murine cells - and vice versa - led to calibration curves with good correlation for human and murine cells...

Clinical cancer research : an official journal of the American Association for Cancer Research, 1999

We have established new human sarcoma lines and examined their sensitivity to common antitumor dr... more We have established new human sarcoma lines and examined their sensitivity to common antitumor drugs and expression of putative multidrug resistance (MDR) proteins. Eighty-two sarcoma samples were transplanted in nude mice. Fourteen of these sarcomas were established as tumor cell lines. We determined a chemosensitivity profile to antitumor drugs (MDR drugs = doxorubicin, mitoxantrone, and vincristine; non-MDR drugs = cisplatin, ifosfamide, and bleomycin) for each tumor line in vivo. Response to chemotherapy with doxorubicin and ifosfamide was observed in 30-50% of these tumor lines. Our results obtained with xenotransplants are similar to the results documented in clinical trials in which doxorubicin and ifosfamide are effective in 30-50% of the patients. Furthermore, we examined expression of MDR-relevant markers like P-glycoprotein, MDR-associated protein, lung resistance protein, and mdr1 mRNA in these xenotransplants. A relationship between mdr1 mRNA expression and response to ...

Advances in experimental medicine and biology, 1998

Anticancer research

Standard CD44 (CD44s) and variant isoforms (CD44v) are expressed on different malignant cells and... more Standard CD44 (CD44s) and variant isoforms (CD44v) are expressed on different malignant cells and tissues. Their upregulation has been implicated, in the progression and metastasis of malignomas. In this work we addressed the question of whether these molecules are also expressed on xenografted human breast carcinomas and if certain expression patterns are correlated with biological parameters like tumour size, hormone receptor status, histology, growth rate, chemoresistance and microenvironment. Additionally, we were interested in the shedding of soluble CD44 (sCD44) into the blood circulation of tumour bearing nude mice. The human breast carcinomas MCF-7, MCF-7/ADR, 4296 and MDA-MB435, 4134 and 4151 were transplanted subcutaneously (sc.) or into the mammary fat pad (mfp.) of nude mice. The expression of the CD44s, -v6, and -v9 isoforms was determined at different time points on tissue samples by immunohistochemistry or RT-PCR employing human-specific antibodies or primers, respect...

Bone marrow transplantation, 1996

Peripheral blood progenitor cells (PBPCs) obtained from cytapheresis products (CPs) of tumor pati... more Peripheral blood progenitor cells (PBPCs) obtained from cytapheresis products (CPs) of tumor patients undergoing mobilizing chemotherapy for PBPC support and dose-intensified anticancer chemotherapy initiate multilineage human hematopoiesis after intraperitoneal (i.p.) transplantation into young severe combined immunodeficient (SCID) mice. The engraftment process was significantly accelerated by subcutaneous cotransplants of a rat fibroblast cell line stably transfected with a retroviral vector carrying the human interleukin-3 (hIL-3) gene and producing sustained in vivo levels of circulating human IL-3 over a prolonged period of time. These cotransplants were found to provide a suitable microenvironment for i.p. transplanted CD34-positive cells separated from PBPC preparations using immunomagnetic beads. Flow cytometry analysis and immunocytology revealed that selected PB CD34- cells, more than 90% pure, were capable of initiating and sustaining a productive multilineage hematopoie...

Anticancer research

This paper reports studies on P388 leukemic cells sensitive and resistant to ADR and VCR. The P45... more This paper reports studies on P388 leukemic cells sensitive and resistant to ADR and VCR. The P450 dependent enzyme system and the cytosolic calcium were estimated and are discussed in relation to MDR. It could be shown, in comparison to sensitive P388 cells, that the plasma membrane permeability for fluorescent dyes like rhodamine 123 and fura-2 and the biotransformation of xenobiotics are changed in resistant cells. Whereas the transport behaviour for the dyes is similarly induced in resistant cells independent of the drug which made the MDR, the P450 dependent enzyme activities are strongly increased in P388/ADR in comparison to the P388 and P388/VCR. The cell cycle analysis shows the same effect. Many more cells of P388/ADR are in the S-phase in comparison to P388 or P388/VCR. The LI is also increased in this direction. Therefore, it can be concluded that, depending on the kind of drug which made the MDR, different biochemical mechanisms are activated.

Anticancer research

It was the aim of this study to compare drug-resistant sublines of the murine P388 in relation to... more It was the aim of this study to compare drug-resistant sublines of the murine P388 in relation to resistance markers, the resistant phenotype and immunogenicity. Resistance to drugs either belonging to the MDR type (Doxorubicin, Vincristine, Mitoxantrone) or to the non-MDR type (Methotrexate) was generated in vivo in order to mimic the clinical situation. All resistant sublines expressed the mdr1 gene and the p-glycoprotein determined on m-RNA level or immunohistochemically, while no expression was registered in the parent P388. The rhodamine 123 fluorescence as marker for the energy dependent drug efflux pump was decreased only in the MDR-sublines, while the parent P388 and the Methotrexate-resistant line retained 100% or 90% of the dye, respectively. This indicates that the rhodamine efflux is a more function-related marker for MDR than the mdr1 gene and the pgp. The in vivo characterization of the sublines as regards their sensitivity to cytostatics revealed a clear-cut cross-res...