| 1. |
- Berndtsson, Maria, et al.
(author)
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Induction of the lysosomal apoptosis pathway by inhibitors of the ubiquitin-proteasome system
- 2009
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 124:6, s. 1463-1469
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Journal article (peer-reviewed)abstract
- The lysosomal apoptosis pathway is a potentially interesting therapeutic target. Since apoptosis involving the lysosomal pathway has been described to involve cathepsins, we screened a drug library for agents that induce cathepsin-dependent apoptosis. Using pharmacological inhibitors and siRNA, we identified 2 structurally related agents (NSC687852 and NSC638646) that induced cathepsin D-dependent caspase-cleavage activity in human breast cancer cells. Both agents were found to induce the mitochondrial apoptosis pathway. NSC687852 and NSC638646 were found to inhibit the activity of ubiquitin isopeptidases and to induce the accumulation of high-molecular-mass ubiquitins in cells. We show that 3 other inhibitors of the proteasome degradation pathway induce lysosomal membrane permeabilization (LMP) and that cathepsin-D siRNA inhibits apoptosis induced by these agents. We conclude that a screen for cathepsin-dependent apoptosis-inducing agents resulted in the identification of ubiquitin isopeptidase inhibitors and that proteasome inhibitors with different mechanisms of action induce LMP and cathepsin D-dependent apoptosis.
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| 2. |
- Cabric, Sanja, et al.
(author)
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Islet Surface Heparinization Prevents the Instant-Blood Mediated Inflammatory Reaction in Islet Transplantation
- 2007
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In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 2008-2015
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Journal article (peer-reviewed)abstract
- OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.
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| 3. |
- Eriksson, Mathilda, et al.
(author)
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Utilization of a right-handed coiled-coil protein from archaebacterium Staphylothermus marinus as a carrier for cisplatin
- 2009
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In: Anticancer Research. - 0250-7005 .- 1791-7530. ; 29:1, s. 11-18
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Journal article (peer-reviewed)abstract
- BACKGROUND: The nano-sized right-handed coiled-coil (RHCC) protein, originating from the archaebacterium Staphylothermus marinus, is stable at high salt concentrations, high temperatures, high pressures and extremes of pH. Its crystal structure reveals four hydrophobic cavities which can incorporate heavy metals. Nano-sized compounds have been used to carry cytotoxic drugs to tumours, avoiding delivery to healthy tissue, in part due to enhanced permeability in tumour blood vessels (enhanced permeability and retention effect). MATERIALS AND METHODS: The ability of RHCC to carry the platinum-containing chemotherapeutic drug cisplatin to cells, while retaining the cytotoxic potential was tested both in vitro and in vivo. RESULTS: RHCC was able to bind and enter cells in vitro and was not severely toxic or immunogenic in mice. Moreover, RHCC incorporated cisplatin, without inhibiting the cytotoxic potential of the drug against tumour cell lines in vitro or in vivo. CONCLUSION: RHCC can be used as a carrier of cisplatin without abrogating the effect of the drug.
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| 4. |
- Fayad, Walid, et al.
(author)
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Identification of a novel topoisomerase inhibitor effective in cells overexpressing drug efflux transporters
- 2009
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 4:10, s. e7238-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Natural product structures have high chemical diversity and are attractive as lead structures for discovery of new drugs. One of the disease areas where natural products are most frequently used as therapeutics is oncology. METHOD AND FINDINGS: A library of natural products (NCI Natural Product set) was screened for compounds that induce apoptosis of HCT116 colon carcinoma cells using an assay that measures an endogenous caspase-cleavage product. One of the apoptosis-inducing compounds identified in the screen was thaspine (taspine), an alkaloid from the South American tree Croton lechleri. The cortex of this tree is used for medicinal purposes by tribes in the Amazonas basin. Thaspine was found to induce conformational activation of the pro-apoptotic proteins Bak and Bax, mitochondrial cytochrome c release and mitochondrial membrane permeabilization in HCT116 cells. Analysis of the gene expression signature of thaspine-treated cells suggested that thaspine is a topoisomerase inhibitor. Inhibition of both topoisomerase I and II was observed using in vitro assays, and thaspine was found to have a reduced cytotoxic effect on a cell line with a mutated topoisomerase II enzyme. Interestingly, in contrast to the topoisomerase II inhibitors doxorubicin, etoposide and mitoxantrone, thaspine was cytotoxic to cell lines overexpressing the PgP or MRP drug efflux transporters. We finally show that thaspine induces wide-spread apoptosis in colon carcinoma multicellular spheroids and that apoptosis is induced in two xenograft mouse models in vivo. CONCLUSIONS: The alkaloid thaspine from the cortex of Croton lechleri is a dual topoisomerase inhibitor effective in cells overexpressing drug efflux transporters and induces wide-spread apoptosis in multicellular spheroids.
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| 5. |
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| 6. |
- Larsson, Dhana E., et al.
(author)
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Combination analyses of anti-cancer drugs on human neuroendocrine tumor cell lines
- 2009
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In: Cancer Chemotherapy and Pharmacology. - : Springer Science and Business Media LLC. - 0344-5704 .- 1432-0843. ; 65:1, s. 5-12
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Journal article (peer-reviewed)abstract
- PURPOSE: There is a large need for better pharmacological treatment of neuroendocrine tumors. The aim of this study was to investigate and quantify the cytotoxic potentiating effects resulting from a combination of five substances, NSC 95397, emetine, CGP-74514A hydrochloride, Brefeldin A and sanguinarine chloride, chosen from a previous screening of 1,280 pharmacologically active agents on neuroendocrine tumor cells, with standard cytotoxic agents currently used in the treatment of neuroendocrine tumors. METHOD: The human pancreatic carcinoid cell line BON-1, human typical bronchial carcinoid cell line NCI-H727 and the human atypical bronchial carcinoid cell line NCI-H720 were used. Combinations between doxorubicin, etoposide, oxaliplatin, docetaxel, and each one of the five agents were studied and simultaneous exposures were explored using the median-effect method. RESULTS: Most of the combinations of NSC-95397 and emetine with doxorubicin, etoposide, docetaxel, and oxaliplatin showed synergism, and their remaining combinations were additive. Almost all of the CGP-74514A hydrochloride interactions were additive, while brefeldin A and sanguinarine displayed less synergy but more additive and antagonistic interactions in combination with the standard drugs. CONCLUSION: The synergistic and additive interactions make NSC-95397, emetine, and CGP-74514A hydrochloride potential candidates for incorporation into combination chemotherapy regimens and these drugs might be the suitable candidates for further clinical studies in patients with bronchial carcinoids and pancreatic endocrine tumors.
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| 7. |
- Larsson, Dhana E., et al.
(author)
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Identification and evaluation of potential anti-cancer drugs on human neuroendocrine tumor cell lines
- 2006
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In: Anticancer Research. - 0250-7005 .- 1791-7530. ; 26:6B, s. 4125-4129
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate drug sensitivity in neuroendocrine tumor cell lines. Materials and Methods: In vitro drug sensitivity screening was performed using the fluorometric microculture cytotoxicity assay in one human pancreatic carcinoid and two human bronchial carcinoid cell lines. In addition, a normal human retinal pigment epithelial cell line was used for comparison. A total of 18 drugs with different mechanisms of action were tested. Results: The most active agents were brefeldin A, emetine, bortezomib and idarubicin, having IC50 values < 1 μM in all four cell lines. In addition, the three tumor cell lines showed sensitivity for sanguinarine, Bay11-7085, mitoxantrone, doxorubicin, β-lapachone, NSC 95397 and CGP-74514A. Conclusion: The cell lines were sensitive for several drugs acting in different ways, covering a broad spectrum of mechanisms of action. Some of these compounds may possibly be used in clinical trials and show therapeutic effect in patients with neuroendocrine tumors.
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| 8. |
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| 9. |
- Lönnerholm, Gudmar, et al.
(author)
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In vitro cellular drug sensitivity at diagnosis is correlated to minimal residual disease at end of induction therapy in childhood acute lymphoblastic leukemia.
- 2009
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In: Leukemia research. - Oxford : Elsevier BV. - 0145-2126 .- 1873-5835. ; 33:1, s. 46-53
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Journal article (peer-reviewed)abstract
- Leukemic cells from 85 children with newly diagnosed precursor B-lineage ALL were tested for in vitro drug sensitivity to a panel of anti-cancer drugs. Minimal residual disease (MRD) was measured by RQ-PCR. There was a significant correlation between MRD day 29 and in vitro sensitivity to prednisolone (p<0.001) and doxorubicin (p=0.017), drugs administered during induction therapy. In patients with t(12;21) (n=20), in vitro sensitivity to doxorubicin was an independent factor for MRD <0.1% (p=0.031; R(2)=0.66). Thus, data show that in vitro drug sensitivity at diagnosis is correlated to cell kill during induction therapy as measured by MRD day 29.
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| 10. |
- Mahteme, Haile, et al.
(author)
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Heterogeneous activity of cytotoxic drugs in patient samples of peritoneal carcinomatosis
- 2008
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In: European Journal of Surgical Oncology. - : Elsevier BV. - 0748-7983 .- 1532-2157. ; 34:5, s. 547-552
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Journal article (peer-reviewed)abstract
- AIMS: To investigate if the pattern of cytotoxic drug sensitivity in vitro in patient samples of peritoneal carcinomatosis (PC) is supportive to the current standardized approach for drug selection for perioperative intraperitoneal chemotherapy (IPC). METHODS: The cytotoxic effect of cisplatin, oxaliplatin, irinotecan, 5-fluorouracil, mitomycin-C, doxorubicin and melphalan was investigated in vitro on tumour cells from 223 patient tumour samples of different PC origins. RESULTS: Considerable differences in cytotoxic drug sensitivity between tumour types of the PC entity and within each tumour type were observed. Cisplatin showed high cross-resistance with oxaliplatin but low cross-resistance with doxorubicin and irinotecan. No cross-resistance was found between irinotecan and doxorubicin. The dose-response relationships for melphalan and irinotecan in individual samples showed great variability. CONCLUSIONS: The activity in vitro of cytotoxic drugs commonly used in IPC for PC is very heterogeneous. Efforts for individualizing drug selection for PC patients undergoing IPC seem justified.
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