Thesis (M.P.H.)--University of Texas Health Science Center at Houston, School of Public Health, 2007. / Source: Masters Abstracts International, Volume: 46-01, page: 0342. Adviser: Julie Ellerhorst. Includes bibliographical references.

Orientadores: Laura Sterian Ward, Janete Cerutti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T07:05:33Z (GMT). No. of bitstreams: 1 Barbieri_RaquelBueno_M.pdf: 1118684 bytes, checksum: aea72fb3df76b68d6756c422b46ffc56 (MD5) Previous issue date: 2012 / Resumo: Polimorfismos de genes baixa penetrância têm sido consistentemente associados com a suscetibilidade a uma série de tumores humanos, incluindo o câncer de tireóide. A fim de determinar seu papel no carcinoma medular de tireóide (CMT), foi utilizado o método TaqMan® SNP Genotyping em 138 pacientes com CMTH, 47 pacientes com CMT-s e um grupo controle de 578 indivíduos para genotipagem dos polimorfismos CYP1A2*F (rs762551), CYP1A1m1 (rs4646903), NAT2 C282T (rs1041983), GSTP1 codon 105 (rs1695), TP53 codon 72 (rs1042522). Este estudo demonstrou uma associação entre a presença de alelos polimórficos de CYP1A2*F, GSTP1 e NAT2 e o desenvolvimento de CMTH. A herança do alelo C em homozigose do gene CYP1A 2*F influencia o desenvolvimento de CMTH em mais de 2 vezes. Pacientes que apresentaram o alelo T em homozigose para o gene NAT2 possuem uma probabilidade 3 vezes maior para o desenvolvimento de CMTH e os indivíduos que herdaram o alelo G do gene GSTP1 em homozigose apresentam maior probabilidade de desenvolvimento de CMTH. Uma análise estatística de regressão logística, ajustada para sexo, idade, etnia, tabagismo e os genes CYP1A*F, CYP1A1m1, NAT, GSTP1 e TP53 para os pacientes com CMTH demonstrou que, quando considerado o tamanho do tumor como estimativa de agressividade, o sexo masculino apresentou-se como fator de proteção ao aumento do tamanho do tumor (OR=0,12; p=0,0072). Considerando a recidiva local como estimativa de agressividade, o genótipo alterado do gene GSTP1 apresentou-se como fator de risco para presença de recidiva local (OR=1,17; p=0,035). A análise de regressão logística mostrou que a herança do genótipo C/C dos genes NAT2 (OR=3,87; IC95%=2,11-7,10; p=2,2x10-5) e TP53 (OR=3,87 IC95%=1,78-6,10; p=2,8x10-4) aumentou o risco de CMT-s. Uma análise de regressão indicou que o genótipo C/C do gene TP53 contribui com 8,07% do risco CMT-s. Não foi possível identificar qualquer relação entre os polimorfismos de NAT2 e TP53, sugerindo que são fatores independentes de risco para o CMT-s. Em conclusão, foi demonstrado que os genes de detoxificação e genes de apoptose e controle do ciclo celular estão envolvidos na suscetibilidade ao desenvolvimento de CMT-s e CMTH e podem modular a suscetibilidade à doença / Abstract: Polymorphisms in low penetrance genes have been consistently associated with susceptibility to a variety of human tumors, including thyroid cancer. In order to determine its role in medullary thyroid carcinoma (MTC) TaqMan® SNP Genotyping method was used in 138 patients with HMTC, 47 patients with MTC-s and a control group of 578 for genotyping of polymorphisms CYP1A2*F (rs762551), CYP1A1m1 (rs4646903), NAT2 C282T (rs1041983), GSTP1 codon 105 (rs1695) and TP53 codon 72 (rs1042522). This study demonstrated an association between the presence of polymorphic alleles of CYP1A2 F, GSTP1 and NAT2 and the development of HMTC. The legacy of the C allele in homozygous CYP1A2*F gene influences the development of CMTH in more than two times. Patients who had the T allele in homozygous for the NAT2 gene have a three times more likely to develop HMTC and individuals who have inherited the G allele of GSTP1 gene in homozygous are more likely to develop CMTH. A statistical analysis of logistic regression, adjusted for sex, age, ethnicity, smoking and genes CYP1A*F, CYP1A1m1, NAT, GSTP1, and TP53, in patients with HMTC, showed that, when considering the size of the tumor as an estimate of aggression, sex male presented himself as a protective factor to the increase in tumor size (OR=0.12; p=0.0072). Considering the estimate of local recurrence and aggressiveness, the altered gene GSTP1 genotype appeared as a risk factor for presence of local recurrence (OR=1.17; p=0.035). The logistic regression analysis showed that the genotypes of the NAT2 gene C/C (OR=3.87; 95%CI=2.11-7.10, p=2.2x10-5) and TP53 C/C (OR=3.87; 95%CI=1.78-6.10; p=2.8x10-4) inheritance increased the risk of sporadic MTC. A regression analysis showed that genotype C/C TP53 gene accounts for 8.07% of sporadic MTC risk. In addition, there was no association between the investigated genes and clinical or pathological features of aggressiveness of the tumors or the outcome of MTC patients. In conclusion, we demonstrated that detoxification genes and apoptotic and cell-cycle control genes are involved in the susceptibility of MTC-s and HMTC and may modulate the susceptibility to the disease / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

No description available.

A infecção por HPV de alto risco é considerada um dos principais fatores de risco para o desenvolvimento do carcinoma do colo uterino, um das neoplasias mais freqüentes em mulheres de todo o mundo. As oncoproteínas E6 e E7 de HPV-16 são capazes de induzir a degradação dos genes supressores de tumor p53 e pRb, respectivamente. Mais do que isso, a expressão dessas oncoproteínas está relacionada a alterações na via de PI3K/AKT/mTOR. A proteína quinase mTOR apresenta importante papel no controle da tradução de proteínas e é considerada o principal mediador entre crescimento celular e proliferação. A ativação de mTOR é correlacionada à fosforilação das proteínas eIF4G1 e 4EBP1, aumentando assim a taxa de síntese de proteínas. A Rapamicina é um inibidor específico de mTOR e seus análogos apresentam potente atividade antiproliferativa em um grande número de células tumorais e tumores gerados em animais. Uma vez que as proteínas E6 e E7 são capazes de interagir com diversas proteínas da via que controla a atividade de mTOR optamos por investigar o efeito da rapamicina na proliferação de culturas organotípicas de queratinócitos expressando esses genes. Também avaliamos o efeito dos genes E6 e E7 na atividade de mTOR após o tratamento com essa droga. Para geração de culturas organotípicas de queratinócitos infectamos essas células com vetores retrovirais recombinantes contendo os genes E6 e E7 de HPV-16 em conjunto ou separadamente. Nós também avaliamos o papel da degradação de p53 e pRb na resposta à rapamicina através da utilização de mutantes de E6 e E7 incapazes de induzir a degradação dessas proteínas celulares. Após a infecção dos queratinócitos, os mesmos foram semeados em uma matriz de colágeno. Após 6 dias as culturas foram tratadas com 100ng/ml de rapamicina e permaneceram 60h em contato com a droga. Para análise por imunohistoquímica os tecidos foram fixados em formalina tamponada e emblocados em parafina. A reação de imunohistoquímica foi realizada utilizando os anticorpos contra BrdU, p-4EBP1 (ser 65), p-eIF4G1 (ser 1188) e pAKT (ser 473). Os resultados obtidos ilustram que a rapamicina apresenta efeito antiproliferativo em culturas de queratinócitos contendo o vetor vazio. Por outro lado, culturas contendo o gene E7 são resistentes ao efeito antiproliferativo dessa droga. Essa resistência parece estar relacionada à capacidade de E7 induzir a degradação da proteína pRb, uma vez que em queratinócitos expressando o mutante de E7, incapaz de induzir a degradação dessa proteína, não foi observada resistência. Além disso, a fosforilação de eIF4G e 4EBP1 indica que a expressão de E7 impede que a rapamicina seja capaz de inibir a atividade de mTOR. Esses resultados mostram, pela primeira vez, que o efeito antiproliferativo da rapamicina pode ser superado pela expressão de uma proteína viral, no caso a proteína E7 de HPV-16. / High-risk HPV infection has a major etiologic role in development and progression of cervical cancer, one of the most frequent forms of cancer among women worldwide. HPV-16 E6 and E7 oncoproteins are able to induce degradation of p53 and pRb tumor suppressor proteins respectively. Moreover, the expression of these oncoproteins is related to alterations in the PI3K/AKT/mTOR pathway. The cellular kinase mammalian target of Rapamycin (mTOR) is an important regulator of the cellular protein synthesis machinery and has emerged as a principal mediator of cell growth and proliferation. mTOR activation has been shown to stimulates eIF4G1 and 4EBP1 phosphorylation, thus increasing the rate of protein synthesis. Rapamycin is a specific inhibitor of mTOR signaling pathway and its analogues have demonstrated impressive activity against a broad range of human cancer derived cell lines in culture and in human tumor xenograft models. Since E6 and E7 target several proteins controlling the mTOR pathway we aimed to investigate the effect of Rapamycin in the proliferation of organotypic raft cultures expressing these genes. We also evaluated the effect of E6 and E7 genes in mTOR activity after rapamycin treatment. To generate organotypic culture of keratinocytes we infect these cells with recombinant retroviruses containing HPV-16 E6 and E7 together or separately. We also analyzed the role of p53 and pRb degradation in rapamycin responsiveness by using E6 and E7 mutants lacking the hability to inactivate these cellular proteins. After infection, keratinocytes were seeded on to a collagen matrix. After 6 days, these cultures were treated with 100ng/ml of Rapamycin for 60 hours. BrdU was added in the last 12 hours to evaluate proliferation. For immunohistochemistry analysis tissues were fixed in buffered formalin and embedded in paraffin. Immunohistochemistry reactions against BrdU, p-4EBP1 (ser 65), p-eIF4G1 (ser 1188) and p-AKT (ser 473) were performed The results show that proliferation of organotypic cultures of keratinocytes transduced with empty vector is inhibited by Rapamycin. On the other hand, cultures generated with keratinocytes transduced with E7 gene were completely resistance to the antiproliferative effect of Rapamycin. Moreover, we found that this antiproliferative effect was dependent of Rb degradation since the cells transduced with E7 mutant unable do induce Rb degradation were sensitive. In addition, eIF4G and 4EBP1 phosphorylation indicates that E7 expression impairs mTOR inhibition by rapamycin. AKT phosphorilation indicates that rapamycin resistance could be dependent of Rb inactivation induced by E7 expression. These results show for the first time that the Rapamycin antiproliferative effect is bypassed by the expression of a viral oncogene, in this case the HPV-16 E7. Moreover, E7 expression impairs rapamycin to inactivate mTOR.

The purposes of this study was to demonstrate the induction of alpha interferon mRNA in Sendai virus-induced Namalava cells, to follow the level of alpha interferon mRNA synthesis at the transcriptional level, and to determine whether the Namalava cell line expresses the c-myc oncogene and to what degree. The amount of c-myc message deteted in Namalva cell RNA was about one-tenth that of Daudi cell RNA, whereas no difference in the amount of the c-Ha-ras message was observed between the two cell lines.

published_or_final_version / abstract / Pathology / Master / Master of Philosophy

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Surgery / Master / Master of Philosophy

Vitamin A is known to have an important role in cellular differentiation and proliferation. In addition to regulating normal cellular processes vitamin A has also been shown to possess potent antineoplastic activity. The work in this dissertation characterizes the role of retinoic acid (RA) in cellular transformation and tumorigenesis with known oncogene involvement. These studies were initiated by examining the effects of RA on human carcinoma cell lines which express an activated c-ras gene. The bladder carcinoma, EJ/T24 (c-rasᴴ) and the two lung carcinoma cell lines, LXl (c-rasᴷ) and A2182 (c-rasᴷ), were not sensitive to RA. No inhibition of anchorage- or density-dependent growth was observed. Therefore, since these in vitro markers of transformation indicated a lack of effectiveness of RA on carcinomas containing a c-ras gene, retrovirally transformed cells were tested for RA sensitivity. Kirsten murine sarcoma, Balb/c murine sarcoma virus, and Simian sarcoma virus transformed NIH/3T3 and NRK cells were used in these studies. In contrast to the human carcinoma cell lines, anchorage-independent growth of some of the virally transformed cells was very sensitive to inhibition by RA. Anchorage-independent growth of KNRK and SSVNRK cells was sensitive to high concentrations (5 μM) of RA; whereas, Balb/cMSV3T3 and SSV3T3 were sensitive to 1-20 nM RA. BALB/cMSVNRK anchorage-independent growth was stimulated 3.5 fold by 1 μM RA. KNRK displayed a 60% reduction in anchorage-dependent growth at 10 μM RA while little inhibition was observed with the other retrovirally transformed cells. A high level of sensitivity to RA inhibition of anchorage-independent growth was correlated with the presence of cytoplasmic retinoic acid binding protein (CRABP). This indicated that CRABP may have some role in the inhibition of retrovirally induced cellular transformation. RA was shown to significantly reduce the incidence and size of Balb/cMSV3T3 cell tumors in nude mice. The inhibition of tumorigenesis in vivo therefore confirmed the results observed in vitro. To investigate the mechanism by which RA was acting to inhibit retroviral transformation, v-onc mRNA levels were examined. RA had no effect on v-onc mRNA levels in cell lines sensitive to the inhibition of transformation. The effect of RA on the relative rate of synthesis of p21, the transforming protein of KMSV and Balb/cMSV, was investigated. No effect of RA was observed in any of the cell lines. Also, GDP binding by p21 in KNRK cell was unchanged by RA treatment indicating that the functional activity of this transforming protein was not modified. RA does appear to be effective in inhibiting retrovirally induced cellular transformation and tumorigenesis. Evidence presented here indicates that this inhibition is not due to a direct effect of RA on the expression of the v-onc gene and/or gene product. Therefore, some other essential cooperating event(s) occurring within the cell are being acted upon by RA.

Thesis is submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Science (Biochemistry), University of the Witwatersrand, Johannesburg, 1992 / An investigation has been made into aspects of the expression of oncogenes in normally dividing cells and in hepatoceilular carcinoma (Hee). HOC occurs commonly in Southern Africs, and thf1aetiology ·ofthis tumour lsaseccieted with hepatitis a virus (HBV) infection. c·erbA, c..mva and e-tos but not c~Ha..res mANA were elevatad in tumours and adjacent hepatic tissue from the same petiEJ;htswhen compared to normal liver. Amounts of Fos and MYQ prot~in in the liver tumour specimens were else raised. The"e was some correlation between the patients' serum a..fetoproteirt concentretlons, histological features of tumour differentiatic)t"l, c..mvc and c40s r.ixpression. expression of e-tas and c..myc has been reportec to be elevated after stimulation of cells to alvlde, ,'1$ occurs during liver r19ganeration. This was corroborated by the findin~ that c-mvc, c·fo~· and c-jun mRNA concentratlona "Jere increased it"! cultured 3T6 mouse fibroblasts following treatment with alkaline medium aa a mitogenlo stimulus. The time course of the expression of these oncogenes was similar to that reported after gro\l'l/th factor sttmulation, The H[~V X..gene ma\' be responsible for increased oncogene expression it' YCC as a result of its documented trans activating properties. This vi!'a~ gene is unusual in that it has a codon preferanc";which is similar to that of eukarvotic ceU genes. Also HBV may ha'V& evolved from ti similar ancestral virus to that giving rise to retroviruses. These ideas suggest that the HBV X·gene is a viral oncogene derived from a host homologue. Low stringency Northern brot hybridisation using a X-gene probe denlonstrated a murine transcrlpt in heart and thymus. Attempts to isolate the sequence from mouse heart and thymus eDNA libraries ware unsuccessful despite ext,~n$jve screening with sensitive probes (SP6 palymerfjsa and peR fab(':.lUed X~gen~~fragments). Conserved X~gene \ . I sequences were also used fot the desigr:Jof primers in .~.peR bas£'d method " . II aimed at isolating a mammalian sequence. No sinnificant sequsnce \\ homology was found bet\lveen the HBVI\X..gene and Ol\A ampllfle'd from \1 l! gen(llmic and eDNA I1br'srytemplate sou~\pes.The peR preducts ttppeared to have been artef.,ots of arnplWaation. ~~n'IJreto detect the hQrtll.)logous gene may have resu~ted from poo' complS,JIlentarity between the VIral ant! \\ mammalian secuencec, 1\ \\ Non..~pecific amplification is commonly enct~unter&d when u$1110 PCli'. A qtJick asvmmatrlc re·ampW~catj(ii1 method I,?ssed on eXUOSilin of an " interm.uly' hybrfdising X·gelllapfimar we! davisQ\j to confirm FICRprOdu(,ts. The l"n1ithodwas specific irlthat "ver~ single bas~ mlsmatohe$ betwsen the internal primer and tem1>late re;.,ultad in fatJut~ of dete(;tabla \tUim$f extension. / GR 2016