Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CHAPTER I - Prostate cancer is a common disease in the world and in some countries it is one of the main causes of male population mortality. Some molecular markers have been associated with prostate carcinogenesis. To observe changes in transcript levels of the AR, SRD5A2, KLK2, PSMA and PCA3 genes, the mRNA was analyzed in tissues with prostatic adenocarcinoma (PCa, N= 48) and benign prostatic hyperplasia (BPH, N= 25), performed through a differential multiplex RT-PCR assay. Significant differences were observed in the relative expression of these genes between cancerous and non-cancerous tissues. The optical density ratio of the cDNA amplicons between PCa and BPH for the AR gene was 1.6-fold higher for the prostatic adenocarcinoma. On the other hand, the SRD5A2 mRNA levels were associated with BPH and were 1.4-fold higher than that of PCa. For KLK2, PSMA and PCA3, the transcriptional levels were respectively, 1.9-, 1.9- and 5-fold higher in PCa than those in BPH tissues. Of the diagnostics tests carried through individually, the PCA3 gene was that presented higher sensitivity and accuracy, and the inclusion of the serum PSA improved the sensitivity (of 76 to 92%), positive preditive value (of 85 to 94%), negative preditive value (of 60 to 62%) and accuracy (of 74 to 78%). The results suggest that the higher AR, KLK2, PSMA, and PCA3 and/or reduced SRD5A2 genes expression in prostatic tissues may indicate the occurrence of prostate adenocarcinoma; however the PCA3 and serum PSA analysis together are highly promising as auxiliary method in the diagnosis of this cancer. CHAPTER II - Purpose: Prostate cancer (PCa) is the most commonly diagnosed malignancy in men, and it consists of multifactorial and multifocal events. Due to the complexity of the disease process, which includes genome alterations, local invasion, micrometastatic cell extravasations to circulation, invasion of secondary organ tissues, and resistance to hormonal blockage, many markers must be used to represent the multiple and variable events that lead to cancer development. The low specificity of the unique serum marker for prostate cancer diagnostics, PSA, has leaded us to investigate four potential markers in the peripheral blood of patients by detecting their mRNA levels and associating them to clinical parameters. Methods: The expression levels of the KLK2, KLK3, PCA3 and PSMA transcripts were determined by Nested RT-PCR. Patients with PCa (99) and with benign prostatic hyperplasia (BPH, 36), and healthy volunteers (104) were investigated. Results: Significant differences for the RNA relative levels have been found for the KLK2, PCA3 and PSMA transcripts between PCa and BPH patients or healthy volunteers. The KLK2 and PSMA levels also presented a positive association (P<0.05) with extra-prostatic disease (pT3). The combined positive RT-PCR Nested for the KLK2, PCA3, PSMA genes with serum PSA higher than 4ng/mL presented a 10-fold higher chance of cancer occurrence than healthy controls, with sensitivity, specificity and positive predictive value of 57%, 89% and 93%, respectively. Conclusions: The combined analysis of KLK2, PCA3 and PSMA transcripts may become a useful tool for the discrimination of PCa patients from those with benign disease or healthy individuals. Additionally, the KLK2 and PSMA transcripts may also be used as prognostic markers for the presence of extra-capsular disease and assisting in the prediction of the post-operative outcome. CHAPTER III - Purpose: Transcripts of PCA3/DD3 gene are at the moment the most specific molecule found in prostate cancer specimens. This mRNA can be detected in important sample targets for clinical analyses, such as prostatic tissues, urine after prostatic massage, and the peripheral blood. Methods: The present study evaluated the PCA3 gene expression in prostatic tissues and in peripheral blood of BPH and PCa patients, by RT-PCR assays, and based on its detection together with other clinical parameters, we proposed a model for molecular monitoring in order to improve diagnosis as an auxiliary technology. Results: The concomitant use of PCA3 transcript detection in the peripheral blood and in prostate tissues has improved diagnosis, with sensitivity and an accuracy of 77%. For the molecular staging, patients have been classified as: localized disease (PBL-; negative PCA3) and circulating tumors cells disease (PBL+; positive PCA3). The higher frequencies of PBL- had been observed in T1-T2 stages (75%); on the other hand, the higher PCA3 positivity was observed for the T3-T4 staging (43%), while the T1-T2 stages presented 25% positivity. A correlation was found between the molecular staging and serum PSA < 10ng/mL before surgery, and approximately 60% of patients with T3-T4 stages that presented biochemical failure after radical prostatectomy presented a positive PCA3 result (P= 0.05), with an odds ratio of 16-fold higher for the possibility of disease recurrence in relation to the T1-T2 patients, and an accuracy of 82%. Conclusion: These data demonstrated the importance of the PCA3 gene as an auxiliary method in prostate cancer diagnosis, by distinguishing PCa from BPH patients, and also demonstrated its prognostic value in recurrent disease for post-operative patients. CHAPTER IV - Approximately 98% of all the products transcribed in the human genome correspond to non coding RNAs (ncRNA). Many ncRNA functions are attributed to this structural particularity given mainly for the secondary structures formed from its linear sequence of bases. Among the ncRNA types are tRNA, rRNA, small nuclear RNA, small nucleolar RNA, small interference RNA (siRNA), microRNA (miRNA) and catalytic RNAs (ribozymes). The bioinformatics has supplied useful tools in the prediction of optimal or suboptimal secondary structures allowing the design of interference RNA as miRNAs or siRNAs. In human, miRNAs have been associated with the development of diverse complex diseases as cancer. The PCA3 (DD3) gene was molecularly characterized as cancer and prostate specific, and its transcripts are non-coding, once no peptide products have been found. Due to its structural characteristics, the PCA3 gene belongs thus to the increasing family of ncRNA. In the present work, four new variant molecules of the PCA3 gene have been sequence characterized and their frequencies demonstrated in prostate cancer and in benign prostatic hyperplasia patients, as well as in healthy individuals. We have also investigated and predicted the putative secondary structures formed in order to elucidate its role in prostate cancer biology. No association has been found between the frequency of these molecules and prostate pathologies (PCa or BPH). On the other hand, PCA3 variants were found in 10% (12/115) of cases in the general population. Similar analyses of the possible polypeptides of these molecules demonstrated that it remains as a non-coding RNA, and introns presents in the first, second and fourth variants suggesting a possible role as a miRNA with intracellular activity to these molecules to the PCA3 gene. In prostatic tissues, 100% of the prostate cancer cases presented the RNA molecule with an exon 2 splicing. However, further investigation must be carried out to demonstrate the true role of these splicing variants in prostate tumors and in other pathologies, once these molecules have been preferentially found in the peripheral blood. / CAPÍTULO I - O câncer de próstata é uma doença comum no mundo e já assumiu em alguns países uma das principais causas de mortalidade da população masculina. Vários marcadores moleculares têm sido associados à gênese do câncer de próstata. A fim de demonstrar a expressão diferencial dos níveis transcricionais dos genes AR, SRD5A2, KLK2, PSMA e PCA3 em doenças prostáticas, o RNAm foi analisado em tecidos com adenocarcinoma prostático (CaP, N= 48) e hiperplasia prostática benigna (HPB, N= 25) por meio da técnica RT-PCR multiplex semi-quantitativa. Foram observadas diferenças significativas na expressão relativa desses genes entre os tecidos cancerosos e nãocancerosos. A taxa de densidade ótica entre os amplicons para cDNA provenientes do gene AR foi 1.6 vezes maior no adenocarcinoma prostático. Por outro lado, os níveis de RNAm do gene SRD5A2 foi associado com a HPB e foi 1.4 vezes maior do que no CaP. Para os genes KLK2, PSMA e PCA3, os níveis transcricionais foram respectivamente, 1.9, 1.9 e 5 vezes maior no câncer comparado a tecidos benignos. Dos testes diagnósticos realizados, o gene PCA3 individualmente foi o que apresentou as melhores sensibilidade e acurácia, sendo que a inclusão das medidas de PSA sérico melhorou a sensibilidade (de 76 para 92%), o valor preditivo positivo (de 85 para 94%), o valor preditivo negativo (de 60 para 62%) e a acurácia (de 74 para 78%). Os dados sugerem que a maior expressão dos genes AR, KLK2, PSMA e PCA3 ou expressão reduzida do gene SRD5A2 em tecidos prostáticos podem indicar a ocorrência do adenocarcinoma da próstata, sendo que as análises do gene PCA3 juntamente aos do PSA sérico são altamente promissores como método auxiliar no diagnóstico desse tipo de câncer. CAPÍTULO II - O câncer de próstata (CaP) e o mais comumente diagnosticado na população masculina e consiste de eventos multifatoriais e multifocais. Devido a complexidade da doença, a qual inclui alterações genômicas, invasão local, liberação de células micrometastáticas para a circulação, invasão secundaria de tecidos de outros órgãos, e resistência ao bloqueio hormonal, muitos marcadores podem ser usados para representar os eventos múltiplos e variáveis que levam ao desenvolvimento do câncer. A baixa especificidade do único marcador para diagnostico do câncer de próstata, PSA, tem nos levado a investigar quatro potenciais marcadores no sangue periférico de pacientes pela detecção de seus níveis de RNAm e associá-los a parâmetros clínicos. Os níveis de expressão dos transcritos do KLK2, KLK3, PCA3 e PSMA foram avaliados pela RT-PCR Nested, em pacientes com CaP (99), com hiperplasia prostática benigna (HPB, 36) e voluntários saudáveis (104). Diferenças significativas foram encontradas para a expressão dos genes KLK2, PSMA e PCA3 entre os pacientes com CaP e os pacientes com HPB ou voluntários saudáveis. Os níveis do KLK2 e PSMA também apresentaram associação positiva (P<0.05) com doença extra-prostática (pT3). A RT-PCR Nested positiva combinada para os genes KLK2, PCA3 e PSMA com PSA sérico maior que 4ng/mL apresentou uma chance 10 vezes maior de ocorrência do câncer comparado aos controles saudáveis, com sensibilidade, especificidade e acurácia de 57%, 89% e 93%, respectivamente. A análise combinada dos genes KLK2, PCA3 e PSMA pode ser uma ferramenta útil na distinção de pacientes com CaP daqueles com doença benigna ou de indivíduos saudáveis. Ainda, a analise dos transcritos KLK2 e PSMA podem ser usados como marcadores prognósticos para a presença de doença extra-capsular e auxiliando na predição de recidiva da doença no pós-operatório. CAPÍTULO III - Os transcritos do gene PCA3/DD3 são até o momento as moléculas mais específicas encontradas em espécimes de câncer de próstata. Esses RNAm podem ser detectados em importantes alvos para a análise clínica como tecidos prostáticos, na urina após massagem prostática e em sangue periférico. O presente estudo avaliou a expressão do gene PCA3 em tecidos prostáticos e em sangue periférico de pacientes com HPB e CaP, por técnicas de RT-PCR, e baseado na sua detecção juntamente com os parâmetros clínicos, foi proposto um modelo de estadiamento molecular como técnica assessória para melhor o diagnóstico da doença. O uso concomitante da detecção dos transcritos do gene PCA3 no sangue periférico e no tecido prostático melhorou o diagnóstico, com sensibilidade e acurácia de 77%. Para o estadiamento molecular, os pacientes foram classificados como contendo a doença localizada (PBL-) e em doença com células tumorais circulantes (PBL +). Maiores freqüências de tumor localizado pelo estadiamento molecular foram observadas nos estadios T1-T2 (75%), enquanto que 25 e 43% dos cânceres T1-T2 e T3-T4, respectivamente, apresentaram PCA3 positivo (células circulantes). Uma correlação foi encontrada para o estadiamento molecular para doença localizada e PSA sérico pré-cirúrgico < 10ng/mL, e aproximadamente 60% dos pacientes TNM T3-T4 que apresentaram falha bioquímica após a cirurgia radical apresentaram RTPCR positiva do PCA3 (P= 0.05), com um Odds Ratio 16 vezes maior para a possibilidade de recorrência da doença em relação aos pacientes T1-T2 e uma acurácia de 82%. Esses dados demonstram a importância da detecção do gene PCA3 como método no diagnóstico do câncer de próstata, por distinguir pacientes com CaP daqueles com HPB, e também demonstrando seu valor prognóstico na doença recorrente no pósoperatório dos pacientes. CAPÍTULO IV - Aproximadamente 98% de todos os produtos transcritos do genoma humano correspondem a RNAs não codificantes (RNAnc). Muitas funções dos RNAnc são atribuídas a suas particularidades estruturais dadas principalmente pelas estruturas secundárias formadas a partir da sua sequência linear de bases. Dentre os tipos de RNAnc estão os RNAt, RNAr, small nuclear RNA, small nucleolar RNA, small interference RNA (siRNA), microRNA (miRNA) e RNAs catalíticos (ribozimas). A bioinformática tem fornecido ferramentas úteis na predição de estruturas secundárias ótimas ou subótimas permitindo o design de RNAs de interferência como os miRNAs ou siRNAs. Em humanos, os miRNAs tem sido associados ao desenvolvimento de diversas doenças complexas como o câncer. O gene PCA3 (DD3) foi molecularmente caracterizado como câncer- e próstata- específico e os seus RNAs são os responsáveis por essa característica, isso porque nenhum produto protéico tem sido encontrado para esse gene. Devido às suas características estruturais, o gene PCA3, pertence assim à crescente família de RNAnc. No presente trabalho foi analisado as freqüências de quatro moléculas variantes do gene PCA3, além das anteriormente reportadas, como também foram preditas as suas estruturas secundárias na tentativa de elucidar o seu papel na biologia do câncer de próstata. Nenhuma associação foi encontrada entre a freqüência dessas moléculas e as patologias da próstata como hiperplasia benigna ou câncer, sendo que na população geral analisada essas variantes foram encontradas em apenas 10% (12/115) dos casos. As análises de homologia de possíveis polipeptídeos para essas moléculas demonstram que permanece o papel de RNA não-codificante para o gene PCA3. Ainda, a presença de introns nas variantes 1, 2 e 4 podem sugerir um papel intracelular de miRNA para essas moléculas do gene PCA3. Nos tecidos prostáticos, 100% dos casos de câncer foi representando pela molécula com splicing do exon 2. Contudo, para as variantes de splicing, novas pesquisas deverão ser realizadas incluindo outras patologias além das doenças prostáticas e outros tipos tumorais para verificar o real impacto dessas moléculas, uma vez que foram encontradas preferencialmente no sangue periférico. / Doutor em Genética e Bioquímica

At present, prostate cancer is a significant public health issue throughout the world and is the second leading cause of cancer deaths in older men. The prostate specific antigen or PSA (which is encoded by the kallikrein 3/KLK3 gene) test is the current most valuable tool for the diagnosis and management of prostate cancer. However, it is insufficiently sensitive and specific for early diagnosis, for staging of prostate cancer or for discriminating between benign prostatic hyperplasia (BPH) and prostate cancer. Recent research has revealed another potential tumour marker, glandular kallikrein 2 (KLK2 gene/hK2 protein), which may be used alone or in conjunction with PSA to overcome some of the limitations of the PSA test. Twelve new kallikrein gene family members have been recently identified and, like hK2 and PSA, many of these genes have been suggested to be involved in carcinogenesis. In this study, the cellular localisation and level of expression of several of these newer kallikreins (KLK4, KLK5, KLK7, KLK8 and KLK11) was examined in prostate tissue, to provide an understanding of the association of their expression with prostatic diseases and their potential as additional biomarkers. Like PSA and hK2, the present observation indicated that each of these proteins, hK4, hK5, hK7, hK8 and hK11, was detected within the cytoplasm of the secretory cells of the prostate glands. For the first time, all of these newly-identified proteins were shown to be expressed in prostatic intraepithelial neoplasia (PIN) lesions, in comparison to normal glands and cancer lesions. In addition to cytoplasmic secretory cell expression, the localisation of hK4 to the basal cells and nuclei in prostatic lesions was intriguing. The intensity of hK4 staining in prostate tissue was strongest in comparison to the other newly-identified kallikrein proteins (hK5, hK7, hK8 and hK11). Therefore, KLK4/hK4 expression was characterised further to define this cellular localisation and examined in non-prostatic tissue and also in a larger number of prostate tissues in an attempt to determine its potential value as a biomarker for prostate disease. Three hK4 antipeptide polyclonal antibodies, derived against N-terminal, mid-region and C-terminal hK4 amino acid sequences, were used. The hK4 N-terminal antipeptide antibody was used to demonstrate the cellular localisation of hK4 in kidney, salivary glands, liver, testis, colon carcinoma, heart, endometrium and ovarian cancer, for the first time. The presence of hK4 in these non-prostate tissues was consistent with the previous reports using RT-PCR. The dual cytoplasmic and nuclear localisation of hK4 observed in the prostate above was also seen in these tissues. Although hK4 was found widely expressed in many human tissue types, indicating that it is not prostate specific in its expression, the highest expression level of hK4 was seen in the prostate. Therefore, detailed expression patterns and levels of KLK4 mRNA and hK4 protein in the normal prostate and prostatic diseases and histopathological lesions were investigated and reported for the first time in this study. Twelve benign prostatic hyperplasia (BPH), 19 adenocarcinoma (Gleason grade 2-5) and 34 bone metastases from prostate cancer were analysed. Using in situ hybridisation, the expression of KLK4 mRNA was detected in the cytoplasm of the secretory cells of both normal and diseased prostate tissue. KLK4 mRNA was also noted in both secretory and basal cells of PIN lesions, but the basal cells of normal glands were negative. Using the hK4 N-terminal and mid-region antipeptide antibodies, hK4 was predominantly localised in the cytoplasm of the secretory cells. The intensity of hK4 staining appeared lowest in normal and BPH, and increased in PIN lesions, high Gleason grade prostate cancer and bone metastases indicating the potential of hK4 as a histopathological marker for prostatic neoplasias. Further studies are required with a larger cohort to determine its utility as a clinical biomarker. Small foci of atypical cells, which were found within normal glands, were also intensely stained. Surprisingly, hK4 protein was found in the nucleus of the secretory cells (but not the basal cells) of high grade PIN and Gleason grade 3 prostate cancer. The detection of KLK4 mRNA and hK4 protein in PIN lesions and small foci of atypical cells suggests that up-regulation of KLK4 expression occurs early in the pathology of prostate carcinogenesis. The finding of basal cell expression is not typical for the kallikreins and it is not clear what role hK4 would play in this cell type. With the use of the hK4 C-terminal antipeptide antibody, the staining was mainly localised in the nuclei of the secretory cells of the prostate glands. Although the nuclear localisation was readily noted in more than 90% of epithelial cells of the prostate gland with the C-terminal antibody, no difference in staining intensity was observed among the histopathological lesions of the prostate. The prominent nuclear localisation with the C-terminal antipeptide antibody was also shown to be distributed throughout the nucleus by using confocal microscopy. Further, by using gold-labelled particles for electron microscopy, the intracellular localisation of these hK4 antipeptide antibodies was reported here for the first time. Similar to the immunohistochemical results, the cytoplasm was the major site of localisation with the N-terminal and mid-region antipeptide antibodies. To further characterise the involvement of KLK4/hK4 in human prostate cancer progression, the transgenic adenocarcinoma mouse prostate (TRAMP) model was used in this study. In this study, mouse KLK4 (also known as enamel matrix serine protease -1, EMSP-1) was shown to be expressed in the TRAMP prostate for the first time. Previous studies had only shown the developing tooth as a site of expression for EMSP-1. The level of EMSP-1 mRNA expression was increased in PIN and prostate cancer lesions of the TRAMP model, while negative or low levels of EMSP-1 mRNA were seen in normal glands or in control mouse prostate tissue. The normal mouse prostate did not stain with any the three hK4 antipeptide antibodies. hK4 N-terminal and mid-region antipeptide antibodies showed positive staining in the cytoplasm of the epithelial cells of PIN and cancer lesions of the mouse prostate. The C-terminal antipeptide antibody showed distinctively nuclear staining and was predominantly localised in the nuclei of the glandular cells of PIN and cancer lesions of the mouse prostate. The expression patterns of both the mRNA and protein level for mouse KLK4 strongly supported the observations of KLK4/hK4 expression in the human prostate and further support the utility of the TRAMP model. Overall, the findings in this thesis indicate a clear association of KLK4/hK4 expression with prostate cancer progression. In addition, several intriguing findings were made in terms of cellular localisation (basal as well as secretory cells; nuclear and cytoplasmic) and high expression in atypical glandular cells and PIN, perhaps indicating an early involvement in prostate disease progression and, additionally, utility as basal cell and PIN histological markers. These findings provide the basis for future studies to confirm the utility of hK4 as a biomarker for prostate cancer progression and identify functional roles in the different cellular compartments.