Made available in DSpace on 2014-12-17T15:32:33Z (GMT). No. of bitstreams: 1 MariaCFNC.pdf: 1259034 bytes, checksum: abf51afcd72b5241d217ca5d19610bd4 (MD5) Previous issue date: 2006-09-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The objective of this study was perform, by the streptoavidin-biotin technique, an immunohistochemical analysis of the E-cadherin and CD44v6 in 15 lower lip squamous cell carcinomas and 15 of tongue, with varied histologic gradation of malignidade, in order to establish a possible relation between the expression these proteins and the anatomical localization of the lesions, metastasis, as well as with the Bryne`s histolologic grading of malignancy system. It was not observed significant statistical association between the localization of the lesions and the malignancy score, however, had a significant correlation between the histologic parameters of malignancy gradation and the total score of malignancy, being that the parameter degree of keratinization presented the highest correlation (r = 0,844). Taking in consideration the anatomical localization of the lesions, it was not significant difference between the profile of expression and the amount of immunopositive cells for Ecaderina and CD44v6. To the metastasis variable, also it was not observed significant difference between the profile of expression and the amount of immunopositive cells for evaluated proteins. However, it was observed a statistical significant difference in relation to the scores of malignancy, being that the low score presented the highest values for the profile of expression and the amount of immunopositive cells for the E-caderina and the CD44v6. It was observed a statistically significant and negative correlation between the expression profile, the amount of E-cadherin and CD44v6 immunopositive cells and the total score of malignancy. Therefore, based in the results of this study, it was concluded that the expression of the immunohistochemical markers E-caderina and CD44v6 did not constitute histological indicator of aggressiveness for the patients with lower lip and tongue squamous cell carcinomas / Este trabalho teve como objetivo verificar, atrav?s da t?cnica da estreptoavidina-biotina, a express?o imuno-histoqu?mica das prote?nas E-caderina e CD44v6 em 15 esp?cimes de carcinoma epiderm?ide de l?bio inferior e 15 de l?ngua, com variada grada??o histol?gica de malignidade, a fim de estabelecer uma poss?vel rela??o entre a express?o das referidas prote?nas e a localiza??o anat?mica da les?o, met?stase, assim como com a grada??o histol?gica de malignidade proposta por Bryne (1998). A an?lise estat?stica demonstrou que n?o houve associa??o significativa entre a localiza??o da les?o e os escores de malignidade, entretanto, houve uma correla??o significativa entre os par?metros de grada??o histol?gica de malignidade e o escore total de malignidade, sendo que o par?metro grau de ceratiniza??o apresentou a maior correla??o (r = 0,844). Levando-se em considera??o a localiza??o anat?mica das les?es, n?o houve diferen?a significativa entre o padr?o de express?o e a quantidade de c?lulas imunopositivas para E-caderina e CD44v6. Em se tratando da vari?vel met?stase, tamb?m n?o houve diferen?a significativa entre o padr?o de express?o e a quantidade de c?lulas imunopositivas para as prote?nas avaliadas. Entretanto, ressalta-se que foi observada uma diferen?a estatisticamente significativa em rela??o aos escores de malignidade, sendo que o escore baixo apresentou os maiores valores para o padr?o de express?o e a quantidade de c?lulas imunopositivas para a E-caderina e o CD44v6. Uma correla??o estatisticamente significativa e negativa entre o padr?o de express?o e a quantidade de c?lulas imunopositivas para a E-caderina e o CD44v6 e o escore total de malignidade foi observada. Portanto, com base nestes resultados, conclui-se que a express?o dos marcadores imuno-histoqu?micos E-caderina e CD44v6 n?o constituiu fator indicativo de maior agressividade morfol?gica para os pacientes portadores de carcinomas epiderm?ides de l?bio inferior e de l?ngua

To personalize treatment for cancer, correct staging of the primary tumor, nodal disease and metastatic disease is of essence. By targeting tumor specific receptors with radiolabeled antibodies, specificity and accuracy of imaging may be improved. Radio-immunodiagnostics can potentially detect small volume disease, occult metastasis and recurrent cancer in treated tissue. This thesis focuses on evaluation of radio-immunoconjugates directed towards CD44v6, which is a surface receptor overexpressed in many head and neck squamous cell carcinomas. At the outset, the monoclonal chimeric antibody cMab U36 and its cleavage products Fab’ and F(ab’)2 were labeled with 125I and assessed in vitro and in vivo (paper I). The best distribution pattern and tumor to organ ratio was achieved with F(ab’)2. Due to the immunological responses humans can develop towards chimeric antibodies, they are not optimal for clinical use, and subsequently fully human antibody fragments were developed. AbD15179, which is a monovalent fragment, was labeled with 111In and 125I and evaluated in vitro and in mice bearing CD44v6-expressing tumors. Tumor to organ ratios were improved compared to cMab U36 derived fragments, and 111In-AbD15179 displayed a more favorable distribution compared to 125I-AbD15179 (Paper II). A bivalent Fab-dHXL, AbD19384 derived from AbD15179, was then constructed and labeled with 125I and evaluated in cell- and biodistribution studies. Furthermore, an imaging study in a small animal PET was performed with 124I-AbD19384 (Paper III). Uptake in kidneys was reduced and liver uptake increased compared to AbD15179 reflecting the larger molecule. The high CD44v6 expressing tumor was clearly visualized with maximum uptake at 48 hours post injection.In paper IV human single chain fragments towards CD44v6v were selected, and the top candidates A11 and H12 were further evaluated in vitro and in vivo. Single chain fragments are small molecules exhibiting fast clearance and high affinity to the target. The study proved this by demonstrating superior tumor to blood ratios of radiolabeled A11 and H12 compared to previously studied molecules.

This thesis focuses on the evaluation of biomarkers for radio-immunodiagnostics and radio-immunotherapy and on radiosensitization strategies after HSP90 inhibition, as a step towards more personalized cancer medicine. There is a need to develop new tracers that target cancer-specific biomarkers to improve diagnostic imaging, as well as to combine treatment strategies to potentiate synergistic effects. Special focus has been on the cell surface molecule CD44 and its oncogenic variants, which were found to exhibit unique expression patterns in head and neck squamous cell carcinoma (HNSCC). The variant CD44v6 seems to be a promising target, because it is overexpressed in this cancer type and is associated with radioresistance. Two new radioconjugates that target CD44v6, namely, the Fab fragment AbD15179 and the bivalent fragment AbD19384, were investigated with regard to specificity, biodistribution and imaging performance. Both conjugates were able to efficiently target CD44v6-positive tumors in vitro and in vivo. PET imaging of CD44v6 with 124I-AbD19384 revealed many advantages compared with the clinical standard 18F-FDG. Furthermore, the efficacy of the novel HSP90 inhibitor AT13387 and its potential use in combination with radiation treatment were evaluated. AT13387 proved to be a potent new cancer drug with favorable pharmacokinetics. Synergistic combination effects at clinically relevant drug and radiation doses are promising for both radiation dose reduction and minimization of side effects, or for an improved therapeutic response. The AT13387 investigation indicated that CD44v6 is not dependent on the molecular chaperone HSP90, and therefore, radio-immunotargeting of CD44v6 in combination with the HSP90 inhibitor AT13387 might potentiate treatment outcomes. However, EGFR expression levels did correlate with HSP90 inhibition, and therefore, molecular imaging of EGFR-positive tumors may be used to assess the treatment response to HSP90 inhibitors. In conclusion, these results demonstrate how tumor targeting with radiolabeled vectors and chemotherapeutic compounds can provide more specific and sensitive diagnostic tools and treatment options, which can lead to customized treatment decisions and a functional diagnosis that provides more precise and safer drug prescribing, as well as a more effective treatment for each patient.