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  • 1
    In: Blood, American Society of Hematology, Vol. 112, No. 11 ( 2008-11-16), p. 3055-3055
    Abstract: RIT in CD 20 positive lymphoma has mainly been studied by using 131Iodine (131I) or 90Yttrium (90Y) labelled antibodies. Lutetium-177 linked to the chimaeric anti CD 20 antibody Rituximab (R) with DOTA (1,4,7,10-tetraaza-cyclododecane-1,4,7,10-tetraacetic acid) as chelator emits beta rays (0.497MeV) and a gamma component (113keV 7%, 208keV 11%) suitable for imaging. Its handling is less hazardous than 131I and the beta component may give a more favourable tumour to non-tumour ratio than 90Y. The aim of the study was to determine the maximum tolerated dose (MTD) and to explore clinical response. Non labelled rituximab (250mg/m2) was given on d1 and d8. 177LU-D-R was injected on d8. Pts were hospitalized for five days for sequential imaging and, at higher doses, to fulfil radiation safety requirements. From Feb 02 to Aug 08 we treated 30 pts (m:16, f: 14, median # of preTx: 3) in 7 cohorts (level 1–7) of 2 to 7 pts. Since activity was already seen at the lowest dose (20 mCi/m2), escalation was carried out in steps of only 5 mCi/m2. No Grade III/IV non- hematologic toxicity was observed (2 pts being too early to evaluate). Gr II fatigue and Gr I nausea were reported mainly on the days following treatment (Tx). Hematologic toxicity: Anemia Gr II: 2 in 7 pts (2/7) at level 4, 1/4 at level 5. No Gr III/IV was seen, no transfusions were required. Lc: Gr III was seen at levels 3–6 each (nadir wk 8), no Gr IV was seen. Neutro: Gr III: 1/5 at level 3, 1/6 at level 4, 1/4 at level 5, 3/4 at level 6 no Gr IV was observed. No neutropenic fever was observed. Tc: One brief Gr IV was seen in 1 of 5 pts at level 3, one Gr III each at levels 4–6 (nadir: wk 7), no bleeding occurred and no Tc transfusions were required (2 pts being too early). Response was assessed by [18F]FDG-PET and CT or PET/CT pre Tx, wk 10 and when clinically indicated thereafter. Responses were seen on all dose levels. Six of 12 pts with untransformed follicular lymphoma (FL) (med age: 59 y, 36–82) remain in remission 74, 71, 71, 32, 6 and 4 months after RIT. One pt treated at the lowest dose had a regression of pleural effusions after RIT, received an allogeneic transplant and has been in remission for 70 months. Two pts with FL have died. One pt with transformed FL had a brief response, then received an autologous transplant and has been in remission for 2 yrs. The 14 pts with mantle cell lymphoma (MCL) (med age: 71 y, 46–85) usually had brief responses in parts of their tumour mass. 10 pts have died. Median time to next Tx was 4 months. One pt with localized indolent MCL responded twice to 177LU-D-R, progressed after the 3rd Tx and is alive 60 months after his 1st dose. One pt had a brief response, then received bortezomib and has been in CR for 2 years (2 pts too early). Other indolent histologies had brief responses. With a maximum observation time of 75 months, no MDS or leukemia was seen. According to national radiation safety requirements 177LU-D- R at a dose of 50mCi/m2 requires a hospital stay of 5 days. This dose seems to have a promising therapeutic index mainly in FL and will be tested in a larger patient cohort. (This study was supported by the JP Obrecht Foundation, Arlesheim, Switzerland and the Swiss Cancer League. Day 1 and 8 Rituximab for pts 1 to 25 was provided free of charge by Roche Pharma Schweiz, Reinach, Switzerland. 177LU-D-R was manufactured at the Radiological Chemistry unit, University Hospital, Basel, Switzerland. Lutetium-177 was purchased either from I.D.B. Holland BV or from Perkin Elmer, USA)
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2008
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 117, No. 3 ( 2011-01-20), p. 902-914
    Abstract: Bone marrow mesenchymal cells (MSCs) can protect leukemic cells from chemotherapy, thus increasing their survival rate. We studied the potential molecular mechanisms underlying this effect in acute lymphoblastic leukemia (ALL) cells. Coculture of ALL cells with MSCs induced on the lymphoblast plasma membrane the expression of a signaling complex formed by hERG1 (human ether-à-go-go-related gene 1) channels, the β1-integrin subunit, and the chemokine receptor CXC chemokine receptor-4. The assembly of such a protein complex activated both the extracellular signal-related kinase 1/2 (ERK1/2) and the phosphoinositide 3-kinase (PI3K)/Akt prosurvival signaling pathways. At the same time, ALL cells became markedly resistant to chemotherapy-induced apoptosis. hERG1 channel function appeared to be important for both the initiation of prosurvival signals and the development of drug resistance, because specific channel blockers decreased the protective effect of MSCs. NOD/SCID mice engrafted with ALL cells and treated with channel blockers showed reduced leukemic infiltration and had higher survival rates. Moreover, hERG1 blockade enhanced the therapeutic effect produced by corticosteroids. Our findings provide a rationale for clinical testing of hERG1 blockers in the context of antileukemic therapy for patients with ALL.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2011
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
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  • 3
    In: Blood, American Society of Hematology, Vol. 114, No. 22 ( 2009-11-20), p. 3085-3085
    Abstract: Abstract 3085 Poster Board III-22 Despite improvements in cure rates, chemotherapy resistance remains a major obstacle to successful treatment in a significant proportion of children with acute lymphoblastic leukemia (ALL), particularly in those with relapsed ALL. Bone marrow mesenchymal cells (MSC) can contribute to generate drug resistance in leukemic cells and several mechanisms have been proposed to explain this effect such as molecular interactions between stroma-derived factor 1a (SDF-1a) and its receptor CXCR4 that could trigger integrin engagement and activation of the downstream signaling cascades which would promote survival of leukemia cells. Recent evidence indicates that integrins can form macromolecular complexes with ion channels, and that the resulting integrin/channel complex can regulate cell survival. Among ion channels, those encoded by the ether-a-gò-gò-related gene 1, hERG1 channels, have been shown to form protein complexes with integrins in several tumor cell types. In experiments with the ALL cell lines REH, RS4;11 and 697 we found that ALL cell contact with MSC induced the expression of a plasma membrane signaling complex constituted by hERG1 channels, the b1 integrin subunit and the chemokine receptor CXCR4 on the surface of ALL cells. This protein complex triggered the activation of pro-survival intracellular signaling pathways. We found that hERG1 channels are central to this protective mechanism. The three cell lines and all cases (n = 63) of primary ALL expressed hERG1; exposure to hERG1 blockers could abrogate the protective effect of MSC and considerably enhanced the cytotoxicity of chemotherapeutic drugs commonly used to treat ALL, such as doxorubicin, prednisone and methothrexate. Indeed, MSC-mediated chemoresistance could be overcome by several hERG1 blockers, including classical class III antiarrhythmics, such as E4031 and Way 123,398, as well as other agents classified as hERG1-blocking drugs, such as sertindole and erythromycin. These results were observed in both ALL cell lines and primary ALL cells and were corroborated by studies in murine models of ALL. In particular, hERG1 blockers could overcome MSC-mediated drug resistance of ALL cells engrafted in immunodeficient mice: mice treated with hERG1 blockers had a marked increase in the rate of apoptosis of ALL cells in the bone marrow, a reduced leukemia burden and ALL infiltration of the liver and spleen. Notably, hERG1 blockers also improved the anti-leukemic effect of corticosteroids in mice injected with corticosteroid-resistant cells (the cell line REH). In fact E4031 reduced bone marrow engraftment, and this effect was related to an increased apoptosis of ALL cells, and was higher than that produced by dexamethasone. Treatment with dexamethasone and E4031 nearly abolished leukaemia development in mice. In sum, hERG1 blockade results impedes ALL cell growth and enhances the effect of anti-ALL chemotherapy. Because some of the hERG1 inhibitors that proved effective in this study are available for clinical use and should not carry the risk of serious cardiac arrhythmia, they should be consider for inclusion in clinical trials for drug-resistance ALL. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2009
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
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