Thesis (Ph. D.)--Case Western Reserve University, 2006. / [School of Medicine] Department of Environmental Health Sciences. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Posttranslational modifications are of great importance in the mediation of transcriptional effects, necessary for signalling in cancer. A characteristic example of such modifications is acetylation of the p53 tumour suppressor, a transcription factor involved in several crucial cellular functions including cell-cycle arrest and apoptosis. p53 is stabilised under hypoxic and DNA damaging-conditions. However, only in the latter scenario is p53 fully capable of inducing the expression of its proapoptotic targets through acetylation. The hypoxia inducible factor 1 (HIF-1) transcription factor is stabilised at low oxygen levels to mediate a cellular adaptive response under these conditions, promoting cell survival. As these two opposing transcription factors share a common transcriptional regulator, p300/CBP, this study focused on deciphering the p300/CBP complex components under differential stress to determine its composition required for cellular responses elicited in response to DNA damage or hypoxia, in an effort to investigate a possible link between differential posttranslational modifications and the resulting cell fate. Hence, the aim of this study was to investigate the roles of p300/CBP components in dictating transcriptional regulation of both HIF-1 and p53 in hypoxic conditions. To carry out this study, the proapoptotic BID gene was the system used, as its promoter contains a p53 response element and a HIF-1 response element (HRE). The p300/CBP associated factors PCAF and Strap were appointed as potent candidates for posttranslational modifications under differential conditions, as they are stress-responsive cofactors. Under DNA damage, PCAF acetylates p53 at K320 and Strap augments p300 binding to p53, both of which amplify the p53 response. Evidence from this study demonstrates that under hypoxia-mimicking conditions PCAF-mediated p53 acetylation at K320 is reduced to a greater extent compared to p300/CBP acetylation at K382. The limited amounts of acetylated p53 at K320 are preferentially recruited to the promoter of the cell cycle arrest p21WAF-1/CIP-1 gene that appears to be unaffected by hypoxia, but fail to be recruited to the BID promoter, rendering p53 incapable of upregulating proapoptotic BID in hypoxic conditions. In addition, under the same conditions, PCAF was found to acetylate, and direct HIF-1 to a particular subset of its targets, leading to alterations in the net physiological effect. Moreover, the intrinsic acetyl transferase activity of PCAF was shown to increase the stability of HIF-1. An additional role was attributed to PCAF in relation to apoptosis, albeit from another angle. BID protein translocation to the cytoplasm in hypoxic conditions was facilitated by ectopically expressed PCAF.Strap was found to be preferentially recruited to the HRE of the BID promoter in hypoxic conditions, and to exert a transrepression effect that appeared to be p53-dependent. Strap also interacted with specific PCAF isoforms depending on the type of cellular stress. Contrary to PCAF, ectopically expressed Strap did not have any effect on BID subcellular distribution. This study has provided additional insight in the mechanisms by which cofactors are involved in cell fate, either by affecting activity and stability of HIF-1 and p53, or having a direct effect on Bcl-2 member subcellular distribution.

The circadian clock generates circadian rhythms, which participate on regulation of a number of signalling pathways. Disruption of the circadian regulatory mechanism is linked to a development and a progression of certain types of cancer including colorectal tumorigenesis. Progression of tumorigenesis depends on the cell cycle machinery related to cell proliferation and apoptosis. MiRNAs play a role in initiation and progression of tumorigenesis because they interfere in regulatory pathways associated with tumorigenesis. The aim of the thesis was to determinate existence of circadian rhytms in clock controlled genes (Tef, Dbp), miRNAs (miR-1-3p, miR-16-5p, miR-34a-5p, miR-155-5p, miR-192-3p) and genes of the cell cycle machinery (Ccnd1, Ccne1, Ccna1, Ccnb1) and apoptosis (Casp3, Bcl2, Bad). Further, to compare detected circadian rhythms during aging and neoplastic transformation of colon by quantitative RT-PCR. We have observed circadian expression of Tef, Dbp, Ccne1, Ccna1, Ccnb1, Casp3 and Bcl2 in young mice colon, Tef, Dbp, miR-1-3p, Ccne1, Ccna1 in old mice colon and Tef and Dbp in colorectal tumors. In summary, circadian expression of clock controlled genes varied but was maintained in mice colorectal tumors. In aging we demonstrated weakening of circadian rhythms of the genes of the cell...

Objectives: To investigate the effects of serotonin and melatonin (MLT) on the regulation of malignant growth and the activity of serotonin receptors (5HTR1a/-1b) in prostate cancer (PCa) cell lines. Materials and Methods: In four PCa cell lines (LNCaP, 22RV1, PC3, DU145) and two reference cell lines 5HTR1a and -1b, relative mRNA expression levels were assessed. Different serotonin and MLT receptor agonists and antagonists were used in stimulation and inhibition experiments. Results: mRNA expression of 5HTR1b was higher than that of 5HTR1a in all PCa cell lines. Serotonin showed a significant growth stimulatory effect in all PCa lines. The 5HTR1a and -1b agonists/antagonists did not significantly affect viability. MLT inhibited viability only in PC3 cells. Similarly, the 5HTR1a antagonist induced apoptotic changes in PC3 cells only at 10–4M, while the 5HTR1b antagonist induced necrosis at 10–4M in all cell lines. Cell cycle alterations were seen in PC3 and DU145 cells under the influence of the 5HTR1a antagonist. Conclusions: Serotonin receptor antagonists and agonists as well as MLT influence viability and apoptosis of PCa cell lines at supraphysiologic concentrations. In contrast to other reports, our results do not support a regulatory role of serotonin or MLT receptor activation or inhibition in PCa growth. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

No description available.

Introdução: O câncer de próstata (CaP) é o tumor mais comum do homem nos países ocidentais e a segunda causa de óbito por câncer em homens nos EUA, Europa e Brasil. O câncer localizado tem sobrevida câncer especifica elevada quando tratado adequadamente, porém a doença metastática ainda apresenta tratamentos pouco eficientes com sobrevida global de 28%. Os microRNAs (miRNAs) são um grupo de moléculas pequenas de RNA que contém entre 19 a 25 nucleotídeos não codificantes de proteína, com ação fundamental na regulação da expressão gênica. Eles estão envolvidos em processos essenciais nas células normais e neoplásicas como ciclo celular, proliferação, apoptose, metabolismo energético, invasão e metastatização. Objetivos: Realizar estudos in vitro e in vivo usando miRNA em um modelo de câncer de próstata metastático inédito no nosso meio com intuito de analisar o seu potencial como agente terapêutico dessa neoplasia. Métodos: Nos estudos in vitro, três linhagens celulares foram utilizadas (PC3, DU145 e LNCaP). Essas linhagens foram transfectadas com os miRNAs 100, 145 e 373 e seus respectivos antiMiRs utilizando-se lipofectamina. Analisamos a expressão dos genes alvo mTOR, SMARCA5, KRAS, CMYC, MMP9, CD44 por PCR quantitativo em tempo real (qRT-PCR). Foram realizados também estudos de apoptose, ciclo celular e ploidia utilizando o citômetro de fluxo. Alterações no potencial de invasão foram avaliadas pela técnica do matrigel. O modelo in vivo pré-clínico foi desenvolvido pela injeção intra-cardíaca da linhagem PC-3M-Luc-C6 em camundongos NUDE com 9 semanas. O crescimento tumoral foi avaliado com o sistema de bioluminescência in vivo. Após o pleno estabelecimento das metástases no dia 21, os animais foram tratados com três injeções na veia da cauda contendo o miRNA conjugado com o atelocolágeno. Os animais foram sacrificados e no dia 48 para análise dos tecidos. Resultados: miR-100 aumenta a apoptose na LNCaP, e reduz a apoptose na DU145. Na linhagem DU145 o miR 100 inibiu a proliferação. Na análise da expressão gênica o miR-100 inibe SMARCA5 na DU145 e PC3 e mTOR na LNCaP, o anti-miR 100 estimula mTOR e SMARCA5 na LNCaP. O miR-145 promoveu aumento da apoptose em 24% na DU145. Na linhagem PC3 o miR-145 age inibindo a proliferação, com uma diferença absoluta de 18% em relação ao seu controle. O miR-145 inibe KRAS e CMYC nas três linhagens e o anti-miR-145 estimula CMYC na DU145 e RAS nas três linhagens O miR-373 reduziu a apoptose em 29% na DU145 e diminui a proliferação com uma diferença absoluta de 13% em relação ao controle. O miR- 373 estimula a MMP9 na DU145 e na LNCaP e inibe o CD44 na PC3. O antimiR- 373 inibe MMP9 na DU145 e LNCaP. Nos estudos in vivo de CaP metastático o miR-100 apresenta tendência a redução no crescimento tumoral (p=0,23) e o miR-145 reduz o crescimento de forma significativa no dia 34 (p=0,02). Após esses dias o tumor volta a crescer de forma agressiva. Os animais tratados com anti-miR-373 não apresentaram alterações em relação aos controles. Conclusões: O miR-100 é um miRNA contexto dependente, com papel supressor tumoral em linhagens de tumor de próstata agressivo e o miR- 373 age in vitro como oncomiR. O miR-145 age como supressor tumoral in vitro e em modelo animal de CaP metastático apresentando resposta terapêutica consistente, podendo ser utilizado no arsenal terapêutico contra essa neoplasia. Estudos futuros devem avaliar o uso dos miRNAs isoladamente ou de forma adjuvante no tratamento do CaP metastático / Introduction: Prostate cancer (PCa) is the most common neoplasia of man in Western countries and the second cause of death by cancer in men in the US, Europe and Brazil. The localized cancer has high cancer-specific survival when treated properly, however metastatic disease still presents low effective treatments with 28% of global survival. microRNAs (miRNAs) are a group of small RNA molecules containing from 19 to 25 nucleotides of noncoding protein with fundamental action in the regulation of gene expression. They are involved in key processes in normal and neoplastic cells as cell cycle, proliferation, apoptosis, energy metabolism, invasion and metastasis. Objectives: To carry out studies in vitro and in vivo using miRNA in a novel model of metastatic prostate cancer in our country in order to evaluate its potential as a therapeutic agent of this neoplasia. Methods: In the in vitro studies, three cell lines were used (PC3, DU145 and LNCaP). These cell lines were transfected with miRNAs 100, 145 and 373 and their antiMiRs using lipofectamine. We analyzed the gene expression of mTOR, SMARCA5, KRAS, CMYC, MMP9, CD44 by real-time polymerase chain reaction (qRT-PCR). We also performed studies of apoptosis, cell cycle and ploidy using flow cytometer. Changes in the invasion potential were evaluated by the technique of matrigel. The pre-clinical model in vivo was developed by intracardiac injection of PC-3MLuc-C6 cell line in NUDE mice with 9 weeks. Tumor growth was evaluated with an in vivo image system (IVIS). After the full establishment of metastases on day 21, the animals were treated with three injections into the tail vein containing the miRNA plus atelocollagen. The animals were sacrificed on day 48 for tissues analysis. Results: MiR-100 increases apoptosis in LNCaP and reduces apoptosis in DU145. The anti-miR-100 increased apoptosis in 14% in PC3. In cell line DU145, miR-100 inhibited proliferation. In the analysis of gene expression, the miR-100 inhibits SMARCA5 in DU145 and PC3 and mTOR in LNCaP, anti-miR-100 stimulates mTOR and SMARCA5 in LNCaP. The miR-145 promoted an increased in apoptosis by 24% in DU145. In PC3 cell line miR-145 acts by inhibiting the proliferation, with an absolute difference of 18% compared to control. MiR-145 inhibits KRAS and CMYC in the three cell lines and anti-miR-145 stimulates CMYC in DU145 and KRAS in the three cell lines. The miR-373 reduced apoptosis by 29% in DU145 and reduces proliferation with an absolute difference of 13% relative to control. MiR-373 stimulates MMP9 in DU145 and LNCaP cells and inhibits CD44 in PC3. The anti -miR-373 inhibits MMP9 in DU145 and LNCaP. In the in vivo studies of metastatic PCa, miR-100 shows a tendency to decrease tumor growth (p=0.23) and miR-145 reduces tumor growth on day 34 (p=0.02). After those days, the tumor grows back aggressively. Animals treated with anti-miR-373 showed no changes relative to controls. Conclusion: The miR-100 is a context-dependent miRNA, with tumor suppressor role in aggressive tumor cell lines. The miR-373 acts in vitro as oncomiR and miR-145 acts as a tumor suppressor in vitro and in an animal model with consistent therapeutic response and can be used in the therapeutic arsenal against this neoplasia. Future studies should evaluate the use of miRNAs alone or adjuvant in the treatment of metastatic prostate cancer

Introdução: O câncer de próstata (CaP) é o tumor mais comum do homem nos países ocidentais e a segunda causa de óbito por câncer em homens nos EUA, Europa e Brasil. O câncer localizado tem sobrevida câncer especifica elevada quando tratado adequadamente, porém a doença metastática ainda apresenta tratamentos pouco eficientes com sobrevida global de 28%. Os microRNAs (miRNAs) são um grupo de moléculas pequenas de RNA que contém entre 19 a 25 nucleotídeos não codificantes de proteína, com ação fundamental na regulação da expressão gênica. Eles estão envolvidos em processos essenciais nas células normais e neoplásicas como ciclo celular, proliferação, apoptose, metabolismo energético, invasão e metastatização. Objetivos: Realizar estudos in vitro e in vivo usando miRNA em um modelo de câncer de próstata metastático inédito no nosso meio com intuito de analisar o seu potencial como agente terapêutico dessa neoplasia. Métodos: Nos estudos in vitro, três linhagens celulares foram utilizadas (PC3, DU145 e LNCaP). Essas linhagens foram transfectadas com os miRNAs 100, 145 e 373 e seus respectivos antiMiRs utilizando-se lipofectamina. Analisamos a expressão dos genes alvo mTOR, SMARCA5, KRAS, CMYC, MMP9, CD44 por PCR quantitativo em tempo real (qRT-PCR). Foram realizados também estudos de apoptose, ciclo celular e ploidia utilizando o citômetro de fluxo. Alterações no potencial de invasão foram avaliadas pela técnica do matrigel. O modelo in vivo pré-clínico foi desenvolvido pela injeção intra-cardíaca da linhagem PC-3M-Luc-C6 em camundongos NUDE com 9 semanas. O crescimento tumoral foi avaliado com o sistema de bioluminescência in vivo. Após o pleno estabelecimento das metástases no dia 21, os animais foram tratados com três injeções na veia da cauda contendo o miRNA conjugado com o atelocolágeno. Os animais foram sacrificados e no dia 48 para análise dos tecidos. Resultados: miR-100 aumenta a apoptose na LNCaP, e reduz a apoptose na DU145. Na linhagem DU145 o miR 100 inibiu a proliferação. Na análise da expressão gênica o miR-100 inibe SMARCA5 na DU145 e PC3 e mTOR na LNCaP, o anti-miR 100 estimula mTOR e SMARCA5 na LNCaP. O miR-145 promoveu aumento da apoptose em 24% na DU145. Na linhagem PC3 o miR-145 age inibindo a proliferação, com uma diferença absoluta de 18% em relação ao seu controle. O miR-145 inibe KRAS e CMYC nas três linhagens e o anti-miR-145 estimula CMYC na DU145 e RAS nas três linhagens O miR-373 reduziu a apoptose em 29% na DU145 e diminui a proliferação com uma diferença absoluta de 13% em relação ao controle. O miR- 373 estimula a MMP9 na DU145 e na LNCaP e inibe o CD44 na PC3. O antimiR- 373 inibe MMP9 na DU145 e LNCaP. Nos estudos in vivo de CaP metastático o miR-100 apresenta tendência a redução no crescimento tumoral (p=0,23) e o miR-145 reduz o crescimento de forma significativa no dia 34 (p=0,02). Após esses dias o tumor volta a crescer de forma agressiva. Os animais tratados com anti-miR-373 não apresentaram alterações em relação aos controles. Conclusões: O miR-100 é um miRNA contexto dependente, com papel supressor tumoral em linhagens de tumor de próstata agressivo e o miR- 373 age in vitro como oncomiR. O miR-145 age como supressor tumoral in vitro e em modelo animal de CaP metastático apresentando resposta terapêutica consistente, podendo ser utilizado no arsenal terapêutico contra essa neoplasia. Estudos futuros devem avaliar o uso dos miRNAs isoladamente ou de forma adjuvante no tratamento do CaP metastático / Introduction: Prostate cancer (PCa) is the most common neoplasia of man in Western countries and the second cause of death by cancer in men in the US, Europe and Brazil. The localized cancer has high cancer-specific survival when treated properly, however metastatic disease still presents low effective treatments with 28% of global survival. microRNAs (miRNAs) are a group of small RNA molecules containing from 19 to 25 nucleotides of noncoding protein with fundamental action in the regulation of gene expression. They are involved in key processes in normal and neoplastic cells as cell cycle, proliferation, apoptosis, energy metabolism, invasion and metastasis. Objectives: To carry out studies in vitro and in vivo using miRNA in a novel model of metastatic prostate cancer in our country in order to evaluate its potential as a therapeutic agent of this neoplasia. Methods: In the in vitro studies, three cell lines were used (PC3, DU145 and LNCaP). These cell lines were transfected with miRNAs 100, 145 and 373 and their antiMiRs using lipofectamine. We analyzed the gene expression of mTOR, SMARCA5, KRAS, CMYC, MMP9, CD44 by real-time polymerase chain reaction (qRT-PCR). We also performed studies of apoptosis, cell cycle and ploidy using flow cytometer. Changes in the invasion potential were evaluated by the technique of matrigel. The pre-clinical model in vivo was developed by intracardiac injection of PC-3MLuc-C6 cell line in NUDE mice with 9 weeks. Tumor growth was evaluated with an in vivo image system (IVIS). After the full establishment of metastases on day 21, the animals were treated with three injections into the tail vein containing the miRNA plus atelocollagen. The animals were sacrificed on day 48 for tissues analysis. Results: MiR-100 increases apoptosis in LNCaP and reduces apoptosis in DU145. The anti-miR-100 increased apoptosis in 14% in PC3. In cell line DU145, miR-100 inhibited proliferation. In the analysis of gene expression, the miR-100 inhibits SMARCA5 in DU145 and PC3 and mTOR in LNCaP, anti-miR-100 stimulates mTOR and SMARCA5 in LNCaP. The miR-145 promoted an increased in apoptosis by 24% in DU145. In PC3 cell line miR-145 acts by inhibiting the proliferation, with an absolute difference of 18% compared to control. MiR-145 inhibits KRAS and CMYC in the three cell lines and anti-miR-145 stimulates CMYC in DU145 and KRAS in the three cell lines. The miR-373 reduced apoptosis by 29% in DU145 and reduces proliferation with an absolute difference of 13% relative to control. MiR-373 stimulates MMP9 in DU145 and LNCaP cells and inhibits CD44 in PC3. The anti -miR-373 inhibits MMP9 in DU145 and LNCaP. In the in vivo studies of metastatic PCa, miR-100 shows a tendency to decrease tumor growth (p=0.23) and miR-145 reduces tumor growth on day 34 (p=0.02). After those days, the tumor grows back aggressively. Animals treated with anti-miR-373 showed no changes relative to controls. Conclusion: The miR-100 is a context-dependent miRNA, with tumor suppressor role in aggressive tumor cell lines. The miR-373 acts in vitro as oncomiR and miR-145 acts as a tumor suppressor in vitro and in an animal model with consistent therapeutic response and can be used in the therapeutic arsenal against this neoplasia. Future studies should evaluate the use of miRNAs alone or adjuvant in the treatment of metastatic prostate cancer