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- Cheng, Junping, 1965-
(author)
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Radioimmunotherapy in Experimental Head and Neck Squamous Cell Carcinoma : Tumour-targeting in vitro and in vivo
- 2005
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Doctoral thesis (other academic/artistic)abstract
- Radioimmunotherapy (RIT) has been shown to be a practicable way to treat head and neck squamous cell carcinoma. A specific antibody recognizes the charasteristic structure of tumour cells when loaded with cytotoxic agents (toxins, drugs, radionuclides, etc). But RIT kills not only tumour cells with attached radionuclides but also adjacent tumour cells due to the “cross fire effect”. To be efficacious, RIT depends closely on suitable monoclonal antibody, on the properties of the chosen radionuclides, and on a suitable labelling method for attaching radionuclide to antibody. In this study we initially used radionuclide-labelled cMAB U36, via linker DABI in order to improve the retention of radio-conjugates in the tumour cells. Improved retention is important because the longer the radionuclide remains in tumour cells, the more effective will the tumour cells be eradicated. In the investigation, both normal mice and HNSCC-bearing nude mice were used to compare our form of treatment against other radio-iodination methods. In the biodistribution study, normal mice showed that radioactive uptake in organs diminished with time, irrespectively of whether the conjugate was directly or indirectly labelled. But in thyroid, there was a tenfold greater accumulation of direct-labelled than of indirectly labelled conjugate.In tumour-bearing nude mice, by contrast, the results showed promising uptake of radioactivity, but little uptake in direct-labelled conjugate in thyroid. Significant differences were observed on comparing tumour: organ ratios between 131I-cMAb U36 vs. 125I-DABI-cMAb U36.In the present study, cMAb U36 labelled with 211Astatine was initially used to treat HNSCC in nude mice. The biodistribution of 211At-cMAb U36 did not reveal any significant difference between an antibody-blocked group and a non-blocked group. But it did highlight the characteristics of a successful targeting conjugate in HNSCC-bearing nude mice.In the subcutaneous therapy experiment, most of the treated tumours (n=18) had disappeared by the 26th day, in both U36-blocked and non-blocked groups. Treatment in the intravenous therapy experiment had also proved effective. In the antibody non-blocked group, the smallest tumour volume was 25 mm3 (average 111 mm3) vis-á-vis 65 mm3 (average 145 mm3) in the blocked group. None of tumours grew again following treatment.
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- Cheng, Junping, et al.
(author)
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Radioimmunotherapy with astatine-211 using chimeric monoclonal antibody U36 in head and neck squamous cell carcinoma
- 2007
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In: The Laryngoscope. - 0023-852X .- 1531-4995. ; 117:6, s. 1013-1018
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Journal article (peer-reviewed)abstract
- OBJECTIVES: In advanced head and neck squamous cell carcinoma (HNSCC), there is a need for an adjuvant treatment. We aim to evaluate the biodistribution and therapeutic effect of radioimmunotherapy using the alpha emitting, astatine-211-labeled, chimeric monoclonal antibody U36 (U36) on the HNSCC cell line UT-SCC7 in vivo. STUDY DESIGN: Xenograft tumors were inoculated subcutaneously in nude mice. Astatine-211-labeled U36 was injected intravenously with or without blocking of target with nonlabeled U36. METHODS: In the biodistribution experiments, radioactivity was measured in tumors and various organs at set time points. In the therapeutic experiments, two groups (with or without blocking) received therapy, and the tumor growth was compared with that of controls. In addition, one group received nonlabeled U36 only. RESULTS: The biodistribution experiments demonstrated that astatine-211-labeled U36 could target UT-SCC7 xenografts in nude mice. With time, uptake increased in tumors and decreased in normal organs. Nonlabeled U36 did not influence tumor growth. In the two therapy groups, 18 of 20 tumors responded to therapy by decreasing or stabilizing their volumes. Significant difference was seen between the treated groups and the controls (P < .05). CONCLUSION: The study illustrates the specific binding of astatine-211-labeled U36 to HNSCC and suggests radioimmunotherapy with the alpha emitting radionuclide to be a useful treatment modality.
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- Cheng, Junping, et al.
(author)
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Targeting of a head and neck squamous cell carcinoma xenograft model using the chimeric monoclonal antibody U36 radioiodinated with a closo-dodecaborate-containing linker
- 2004
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In: Acta Oto-Laryngologica. - 0001-6489 .- 1651-2251. ; 124:9, s. 1078-85
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Journal article (peer-reviewed)abstract
- OBJECTIVE: High rates of local recurrence and distant metastases following surgery of high-grade head and neck squamous cell carcinoma (HNSCC) necessitate the use of adjuvant systemic treatment. Radioimmunotargeting might be a possible treatment modality in this case. The nuclear properties of 131I make it a suitable isotope for treatment of minimal residual disease and small metastases, but the conventional radioiodine label has poor cellular retention and its radiocatabolites accumulate in the thyroid. We attempted to overcome these problems by using closo-dodecaborate derivatives for attachment of radioiodine. MATERIAL AND METHODS: We investigated the feasibility of targeting an SCC25 HNSCC xenograft in vivo using a benzylisothiocyanate derivative of closo-dodecaborate (DABI) as radioiodine linker and the chimeric anti-CD44v6 antibody U36. 125I was used in biodistribution studies. RESULTS: The use of DABI enabled tumor targeting and decreased the radioactivity uptake of the thyroid. CONCLUSION: Tumor localization of DABI-labeled U36 was similar to its para-iodobenzoate-labeled counterpart, presumably due to the strong dependence of targeting efficiency on tumor size.
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- Cheng, Junping, et al.
(author)
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The use of closo-dodecaborate-containing linker improves targeting of HNSCC xenografts with radioiodinated chimeric monoclonal antibody U36
- 2010
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In: Molecular Medicine Reports. - : Spandidos Publications. - 1791-2997. ; 3:1, s. 155-160
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Journal article (peer-reviewed)abstract
- Radionuclide imaging of head and neck squamous cell carcinoma (HNSCC) using monoclonal antibodies (MAbs) has the potential to contribute to improved diagnosis and staging, thereby making more effective treatment possible. Chimeric monoclonal antibody U36 (cMAb U36), specific to CD44v6 antigen. is a candidate for the targeting of HNSCC. The aim of this study was to compare the influence of indirect iodination via closo-dodecaborate-based linker (DABI) with the influence of direct radioiodination on the biodistribution of the chimeric anti-CD44v6 antibody U36. The study was performed using nude mice bearing UT-SCC7 HNSCC xenografts using the paired-label method. The biodistribution of cMAb U36 labelled directly with I-131 and using DABI with I-125 was compared in the same animals. The influence of DABI on the tumour-to-organ ratio was evaluated. For both conjugates, radioactivity uptake in blood and organs decreased with time, except in tumours and the thyroid. DABI-labelled cMAb U36 was characterised by fast blood clearance and an elevated uptake in the liver and spleen. The use of DABI enabled a 1.5 to 2-fold improvement in the tumour-to-blood and tumour-to-organ ratios in comparison with direct radioiodination, with the exception of the liver and spleen. These results indicate that DABI is a promising linker for the coupling of radioiodine to HNSCC-targeting antibodies.
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- Nestor, Marika, 1976-
(author)
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Antibody-Based Radionuclide Targeting for Diagnostics and Therapy : Preclinical Studies on Head and Neck Cancer
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Antibody-based targeting techniques play an increasingly important role in cancer research. By targeting a structure that is abundant in tumour cells, but rare in healthy tissues, an antibody can mediate the delivery of radioactivity specifically to tumour cells in the body. This idea is particularly appealing for head and neck squamous cell carcinoma (HNSCC), as the advanced stages have a large fraction of spread disease that is difficult to treat with procedures available today. In this thesis, we have investigated possible radioimmunotargeting structures for HNSCC, and found that CD44v6 is a suitable target for antibody-based radiotherapy and diagnostics in this patient group. We have identified radiohalogens as attractive nuclides for such use, and have investigated the possibility of radiohalogenating the anti CD44v6 chimeric monoclonal antibody (cMAb) U36. Several feasible labelling methods were identified, using both direct and indirect labelling. The cMAb U36 was then successfully labelled with 211At and 131I, and preclinically evaluated for therapeutic use. Results proved the astatinated conjugate to be most efficient in this context, demonstrating a specific and dose-dependent cytotoxicity. The cMAb U36 was then evaluated for diagnostic use in thyroid anaplastic carcinoma, using 124I as the diagnostic nuclide. Results in tumour-bearing mice were promising, with all of the tumours identified in micro-PET studies. These results demonstrate how antibody-based radionuclide targeting can provide more sensitive and specific methods for identifying and treating head and neck cancer, and hopefully help improve long-term survival rates for this patient group in the future.
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- Nestor, Marika, et al.
(author)
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Biodistribution of the chimeric monoclonal antibody U36 radioiodinated with a closo-dodecaborate-containing linker : Comparison with other radioiodination methods
- 2003
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In: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 14:4, s. 805-10
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Journal article (peer-reviewed)abstract
- We have evaluated the applicability of the [(4-isothiocyanatobenzylammonio)undecahydro-closo-dodecaborate (1-)] (DABI) linker molecule for antibody radiohalogenation and compared it to radiohalogenation using the linker N-succinimidyl 4-iodobenzoate (PIB) and to direct radiohalogenation using Chloramine T. These studies were performed to assess the potential of DABI conjugates and to optimize the biological properties of halogen-labeled cMAb U36. The three conjugates were evaluated in vitro for their specificity and affinity and in vivo for their biodistribution patterns in normal mice at 1.5, 6, 24, and 96 h pi. Labeling efficiencies of direct CAT labeling, indirect PIB labeling, and indirect DABI labeling were 90-95%, 60%, and 68%, respectively. This resulted in a PIB:cMAb U36 molar ratio of 1.8-2.5 and a DABI:cMAb U36 molar ratio of 4.1. The in vitro data demonstrated specific binding for all conjugates and similar affinities with values around 1 x 10(8) M(-)(1). However, the in vivo data revealed accumulation of the radioiodine uptake in thyroid for the directly labeled conjugate, with a value 10 times higher than the indirectly labeled conjugates 96 h pi. Both the (125)I-PIB-cMAb U36 and (125)I-DABI-cMAb U36 conjugates yielded a low thyroid uptake with no accumulation, indicating different catabolites for these conjugates. This may favor the use of the indirectly labeled conjugates for future studies. Apart from the specific results obtained, these findings also demonstrate how the right linker molecule will provide additional opportunities to further improve the properties of an antibody-radionuclide conjugate.
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| 9. |
- Nestor, Marika, et al.
(author)
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Effect of cetuximab in combination with alpha-radioimmunotherapy in cultured squamous cell carcinomas
- 2011
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In: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 38:1, s. 103-112
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Journal article (peer-reviewed)abstract
- AimThe monoclonal antibody cetuximab, targeting the epidermal growth factor receptor (EGFR), is a promising molecular targeting agent to be used in combination with radiation for anticancer therapy. In this study, effects of cetuximab in combination with alpha-emitting radioimmunotherapy (RIT) in a panel of cultured human squamous cell carcinomas (SCCs) were assessed.MethodsSCC cell lines were characterized and treated with cetuximab in combination with anti-CD44v6 RIT using the astatinated chimeric monoclonal antibody U36 (211At-cMAb U36). Effects on 211At-cMAb U36 uptake, internalization and cell proliferation were then assessed in SCC cells.ResultsCetuximab in combination with 211At-cMAb U36 mediated increased growth inhibition compared to RIT or cetuximab alone in two cell lines. However, cetuximab also mediated radioprotective effects compared to RIT alone in two cell lines. The radioprotective effects occurred in the cell lines in which cetuximab clearly inhibited cell growth during radiation exposure. Cetuximab treatment also influenced 211At-cMAb-U36 uptake and internalization, suggesting interactions between CD44v6 and EGFR.ConclusionsResults from this study demonstrate the vast importance of further clarifying the mechanisms of cetuximab and radiation response, and the relationship between EGFR and suitable RIT targets. This is important not only in order to avoid potential radioprotective effects, but also in order to find and utilize potential synergistic effects from these combinations.
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| 10. |
- Nestor, Marika, et al.
(author)
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In vitro evaluation of the astatinated chimeric monoclonal antibody U36, a potential candidate for treatment of head and neck squamous cell carcinoma
- 2005
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 32:11, s. 1296-304
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Journal article (peer-reviewed)abstract
- PURPOSE: The purpose of this study was to analyse the properties of the astatinated chimeric MAb (cMAb) U36 as a conjugate to selectively target and eradicate head and neck squamous cell carcinoma (HNSCC). METHODS: cMAb U36 was labelled with 211At via the linker N-succinimidyl 4-(trimethylstannyl)benzoate (SPMB). The quality of the conjugate was extensively evaluated for binding and internalisation capacity, and compared with 125I-SPMB-cMAb U36. The cellular toxicity of the astatinated conjugate was assessed in two types of in vitro growth assay and compared with 131I-labelled cMAb U36 (directly labelled). RESULTS: Comparisons between 211At-cMAb U36 and 125I-cMAb U36 demonstrated an optimal functional capacity of the labelled products. Immunoreactivity and affinity assays showed high immunoreactive fractions (>93%), and an affinity in good agreement between the astatinated and iodinated antibodies. For both conjugates, specific binding to HNSCC cells could be demonstrated, as well as some internalisation. Retention of the astatinated conjugate was just slightly lower than for the iodinated conjugate and still reasonable for therapeutic use (31+/-2% vs 42.6+/-1.0% at 22 h), demonstrating no adverse effects from astatination of the antibody. Studies on cellular toxicity demonstrated a dose-dependent and antigen-specific cellular toxicity for 211At-cMAb U36, with about 10% cell survival at 50 decays per cell. The 131I-labelled conjugate was not as efficient, with a surviving cell fraction of about 50% at 55 decays per cell. CONCLUSION: These results indicate that 211At-cMAb U36 might be a promising future candidate for eradicating HNSCC micrometastases in vivo.
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