Epigenetic mechanisms are essential for normal cell development. Alteration in those normal processes leads to malignant cell transformation and with this to cancer development. Use of inhibitors that alter the epigenetics of DNA methylation and histone post translational modifications has lead to the exploration of the epigenetic mechanism involved in silencing of tumor suppressor genes in cancer, including acute myeloid leukemia (AML). Moreover, combinations of inhibitors that target various epigenetic enzymes have being recognized to be more effective in the re-activation of tumor suppressor genes than individual drug treatments. Here, we reported that p15, p21 and E-cadherin genes are more effectively re-expressed using a combination of DNA methyltransferase and histone methyltransferase inhibitors in AML cell lines. Re-expression of hypermethylated p15 and E-cadherin genes required reduced levels of promoter histone 3 lysine 9 (H3K9) methylation rather than inhibition of DNA methylation itself. Moreover, induction of p21 expression was associated with changes in promoter histone 3 lysine 9 methylation (H3K9Me) by achieving inhibition of the histone methyltransferase, SUV39H1, activity. Altogether, our results highlight the potential of combining epigenetic drugs in the re-activation of epigenetically silenced tumor suppressor genes and the need for evaluating histone methyltransferases as therapeutic targets for treatment of acute myeloid malignancies.

Epigenetic mechanisms are essential for normal cell development. Alteration in those normal processes leads to malignant cell transformation and with this to cancer development. Use of inhibitors that alter the epigenetics of DNA methylation and histone post translational modifications has lead to the exploration of the epigenetic mechanism involved in silencing of tumor suppressor genes in cancer, including acute myeloid leukemia (AML). Moreover, combinations of inhibitors that target various epigenetic enzymes have being recognized to be more effective in the re-activation of tumor suppressor genes than individual drug treatments. Here, we reported that p15, p21 and E-cadherin genes are more effectively re-expressed using a combination of DNA methyltransferase and histone methyltransferase inhibitors in AML cell lines. Re-expression of hypermethylated p15 and E-cadherin genes required reduced levels of promoter histone 3 lysine 9 (H3K9) methylation rather than inhibition of DNA methylation itself. Moreover, induction of p21 expression was associated with changes in promoter histone 3 lysine 9 methylation (H3K9Me) by achieving inhibition of the histone methyltransferase, SUV39H1, activity. Altogether, our results highlight the potential of combining epigenetic drugs in the re-activation of epigenetically silenced tumor suppressor genes and the need for evaluating histone methyltransferases as therapeutic targets for treatment of acute myeloid malignancies.

Chronic oxidative injury by allylamine induces proliferative vascular smooth muscle cell (vSMC) phenotypes in the rat aorta similar to those seen in rodent and human atherosclerotic lesions. In this study, we evaluate the potential role of cyclin dependent kinase inhibitors, p21 and p27, and extracellular regulated kinases (ERK1/2) to mediate the proliferative advantage of oxidatively stressed (i.e. allylamine injured) vSMC. Isolated rat aortic SMC from allylamine treated and control rats were cultured on different extracellular matrix (ECM) proteins. Following mitogen restriction, cultures were stimulated with serum with or without inhibitors of NF-kB or MEK. Western blot analysis was performed to identify protein differences between treatment groups. Basal levels of p21 were 1.6 fold higher in randomly cycling allylamine cells than control counterparts seeded on a plastic substrate, a difference lost when cells were seeded on collagen. p27 levels were comparable in both cell types irrespective of substrate. Basal levels of p21 and p27 were 1.4 fold higher in G0 synchronized allylamine cells compared with G0 synchronized control cells seeded on a plastic substrate. Following cell cycle progression, differences in protein levels were not detected. Treatment with 100 nM pyrollidine dithiocarbamate (PDTC) resulted in significant decreases in p21 and p27 in allylamine cells versus control cells following serum stimulation for 9 hours. This decrease was even greater for p21 in allylamine cells when grown on collagen relative to control cells. Alterations in peak and temporal activation of ERK1/2 were observed in allylamine cells seeded on a plastic substrate as compared to control cells, following serum stimulation. Seeding on collagen decreased the enhanced peak phosphorylation of ERK1/2 and increased the sustained activity in allylamine cells compared with control counterparts. Inhibition of ERK1/2 activity resulted in reduced p21 expression in both cells types, but the response was markedly enhanced in allylamine cells, and preferentially observed on a restrictive collagen substrate. We conclude that induction of proliferative (i.e. atherogenic) phenotypes following repeated cycles of oxidative injury involves ERK1/2 activity and modulation of the cyclin dependent kinase inhibitors, p21 and p27, in a matrix-dependent manner.

Non Melanoma Skin Cancer (NMSC) affects 3.3 million Americans each year and results from Ultra Violet Radiation (UVR) damage to DNA in the form of pyrimidine dimers and photoproducts [1]–[5]. Cells directly detect the damage and initiate apoptosis, cell cycle arrest, or DNA repair by modulating p53 and p21 levels [6]–[9]. Current methods of photoprotection include sunscreen, but controversy over safety of some active ingredients necessitates research into more natural alternatives [10]–[12]. In particular, 24 hour incubation with bovine milk sphingomyelin (BSM) has demonstrated photoprotective potential by reducing p21 and p53 levels in keratinocytes (KRTs) after UV radiation [13], [14]. This thesis aims to expand on past BSM research by exploring the mechanism for photoprotection. Normally, sphingomyelin (SM) is metabolically degraded to ceramide which then leads to cell apoptosis [6]. The goals of this thesis were to characterize a fluorescent SM (FSM) to assess changes in intracellular fluorescence distribution after various incubation and post-UV exposure times. FSM was deemed functionally equivalent to BSM by reducing levels of p21 after UV. Furthermore, quantification demonstrated that FSM trafficking and intracellular fluorescence were independent of continuous incubation time, warranting further investigation into shorter timepoints like 1 hour. Across several post-UV timepoints, the 1 hour incubation had a consistently higher average cytoplasmic mean gray value compared to 24 hour incubation. In addition, the no UV control was significantly lower compared to the 24 hour and 12 hour post-UV timepoints. No post-UV differences were observed for the 24 hour incubation, suggesting future work is necessary for the 1 hour incubation, which potentially streamlines future experiments. Two immunofluorescence stains for endogenous SM (lysenin) and ceramide were also optimized for preliminary fluorescence distribution studies and colocalization with FSM. Finally, a 3T3 fibroblast spheroid model was utilized as proof-of-concept for future 3D KRT cultures and depth of dye penetration quantification methods. These findings suggest FSM is an appropriate model for BSM trafficking, a shorter FSM incubation time could potentially be adopted in future studies, dual immunofluorescence staining for SM and ceramide is viable, and spheroids provide a promising model for future 3D KRT studies.

Indiana University-Purdue University Indianapolis (IUPUI) / Neurofibromatosis type 2 (NF2) is an autosomal dominant cancer predisposition in which loss of heterozygosity at the NF2 gene locus leads to the development of tumors of neural crest derived origin, most commonly bilateral vestibular schwannomas. There are currently no FDA approved chemotherapeutic agents for treatment in patients with NF2. Development of therapeutic agents has been hampered by our incomplete knowledge of how Merlin, the protein product of the NF2 gene, functions as a tumor suppressor. In order develop a deeper understanding for how loss of Merlin leads to oncogenic transformation in Schwann cells we have developed a genetically engineered mouse model (GEMM) of Neurofibromatosis Type 2 in which functional expression of Merlin is lost in Schwann cell precursors. In parallel studies utilizing these mice, we have sought to understand the pathophysiology driving tumor formation in Merlin deficient Schwann cells. In Chapter 1, we explore the role of Merlin as a negative regulator of the Group A p21 activated kinases, PAK1 and PAK2. We demonstrate that PAK1, a previously well established oncogene in solid tumors and Merlin binding partner, is hyperactivated in Merlin deficient schwannomas. Through therapeutic interventions and genetic manipulations we demonstrate that inhibition of PAK1 was capable of reducing tumor formation and alleviating sensorineural hearing loss in our NF2 GEMM. In Chapter 2, we investigate the role of NF-kB inducing kinase (NIK) and NF-kB signaling in the formation and growth of Merlin deficient Schwann cell tumors. Prior work in our lab as well as by others demonstrated elevated NF-kB signaling in Merlin deficient Schwann cell tumors. We observed accumulation of a catalytically active fragment of NF-kB inducing kinase and present data that accumulation of a 55Kd constitutively active fragment of NIK is sufficient trigger wild type Schwann cells to form tumors. In vivo however, Schwann cell intrinsic expression of NIK is not required for tumor formation or growth. / 2 years (2021-05-24)

Non melanoma skin cancer (NMSC) is a serious condition caused by chronic ultraviolet (UV) exposure that leads to DNA damage in skin. UV radiation has the potential to lead to DNA damage, which triggers biochemical pathways within a cell. The result is that the cell either undergoes cell cycle arrest, giving the cell time to repair DNA damage, or apoptosis. Sunscreen is the most commonly used treatment for preventing UV induced skin damage, but it involves a number of undesirable and toxic side effects including damaging the dermis, premature aging of skin and underweight child births. This has led to interest in finding safer alternatives to prevent UV damage without the negative side effects of sunscreen. In particular, bovine milk sphingomyelin (SM) is a compound that has the potential to protect against UV damage without any of the dangerous side effects of sunscreen. Here we present the use of SM for UV protection of human keratinocytes (KRTs) to prevent DNA mutations that result from UV exposure. In particular, analysis of the expression of DNA damage biomarkers p21 and p53 was done to determine the potential of SM to prevent DNA damage associated with UV exposure. Both non-SM treated KRTs and KRTs treated with 0.1% SM media 24 hours prior to UV radiation were fixed and IF-stained at 24 hours following 40 mJ/cm2 of UV exposure. Significant differences in both p21 and p53 were observed between the SM treated and non-SM treated cells at the UV dosage level (via t-test; p

Avaliamos neste estudo as expressões da ciclina D1 e da proteína p21, pela técnica de Imuno-histoquímica, para detectar a presença destas proteínas nos núcleos das células do câncer de mama localmente avançado, com o objetivo de correlacionar a concentração destas proteínas com aresposta preditiva ao tratamento quimioterápico neo-adjuvante, utilizandoo esquema docetaxel associado à epirrubicina. A avaliação foi feita previamente e após a realização da quimioterapia neo-adjuvante. A avaliação pré-quimioterápica teve a finalidade de estabelecer um papel preditivo quanto à resposta ao tratamento primário. A avaliação pós-quimioterápica teve a finalidade de explorar a relação entre a persistência da proteína com intervalo livre de doença e sobrevida global. Foram selecionados 72 casos de 162 tumores localmente avançados de mama atendidos no período de janeiro de 1998 a dezembro de 2005, tratados por quimioterapia primária no Ambulatório de Mastologiado Hospital das Clínicas de Ribeirão Preto. Conclusão: a ciclina D1 está relacionada com tumores menores, bem diferenciados e hormônio-sensíveis. Já a proteína p21 está relaciona a tumores pequenos, com estádios iniciais menores, de baixo grau histológico e hormônio-sensíveis. A expressão da ciclina D1 no tumor pré-tratamento quimioterápico não foi capaz de predizer resposta à quimioterapia neo-adjuvante. No entanto, a presença da ciclina D1 e no tumor residual e da p21tanto no tumor pré-tratamento quanto no tumor residual, sugerem melhora no intervalo livre de doença e na sobrevida global. / We evaluate in this study the expressions of the cyclin D1 and the protein p21, with the technique of Immunohistochemistry, todetect the presence of these proteins in the cells of the local advanced breast cancer. The objective was correlate the concentration of these proteins with predictive response to the neo-adjuvant chemotherapy, using docetaxel associated with epirrubicina. The evaluation was performed before and after the neo-adjuvant chemotherapy. The evaluation before the neo-adjuvant treatment had the purpose to establish a predictive value of these proteins with primary treatment response. The evaluations after neo-adjuvant treatment had the purpose to explore the relation between the persistence of these proteins with disease-free survival and overall survival. We selected 72 of 162 cases of local advanced breast cancer who had treated for primary chemotherapy in Hospital das Clínicas de Ribeirão Preto in the period of January of 1998 to December of 2005. Conclusion: Our study concluded that the cyclin D1 is related with small tumors and well differentiated and hormone-sensitive tumors. The protein p21 is relates with small tumors, initial stage tumors, low grade tumors and hormone-sensitive tumors. The expression of cyclin D1 in the tumor before the treatment failed to predict response to the neo-adjuvant chemotherapy. However, the presence of the cyclin D1 in the residual tumor andthe protein p21 before the treatment and in the residual tumors suggest improvement in the disease- free survival and overall survival.

Avaliamos neste estudo as expressões da ciclina D1 e da proteína p21, pela técnica de Imuno-histoquímica, para detectar a presença destas proteínas nos núcleos das células do câncer de mama localmente avançado, com o objetivo de correlacionar a concentração destas proteínas com aresposta preditiva ao tratamento quimioterápico neo-adjuvante, utilizandoo esquema docetaxel associado à epirrubicina. A avaliação foi feita previamente e após a realização da quimioterapia neo-adjuvante. A avaliação pré-quimioterápica teve a finalidade de estabelecer um papel preditivo quanto à resposta ao tratamento primário. A avaliação pós-quimioterápica teve a finalidade de explorar a relação entre a persistência da proteína com intervalo livre de doença e sobrevida global. Foram selecionados 72 casos de 162 tumores localmente avançados de mama atendidos no período de janeiro de 1998 a dezembro de 2005, tratados por quimioterapia primária no Ambulatório de Mastologiado Hospital das Clínicas de Ribeirão Preto. Conclusão: a ciclina D1 está relacionada com tumores menores, bem diferenciados e hormônio-sensíveis. Já a proteína p21 está relaciona a tumores pequenos, com estádios iniciais menores, de baixo grau histológico e hormônio-sensíveis. A expressão da ciclina D1 no tumor pré-tratamento quimioterápico não foi capaz de predizer resposta à quimioterapia neo-adjuvante. No entanto, a presença da ciclina D1 e no tumor residual e da p21tanto no tumor pré-tratamento quanto no tumor residual, sugerem melhora no intervalo livre de doença e na sobrevida global. / We evaluate in this study the expressions of the cyclin D1 and the protein p21, with the technique of Immunohistochemistry, todetect the presence of these proteins in the cells of the local advanced breast cancer. The objective was correlate the concentration of these proteins with predictive response to the neo-adjuvant chemotherapy, using docetaxel associated with epirrubicina. The evaluation was performed before and after the neo-adjuvant chemotherapy. The evaluation before the neo-adjuvant treatment had the purpose to establish a predictive value of these proteins with primary treatment response. The evaluations after neo-adjuvant treatment had the purpose to explore the relation between the persistence of these proteins with disease-free survival and overall survival. We selected 72 of 162 cases of local advanced breast cancer who had treated for primary chemotherapy in Hospital das Clínicas de Ribeirão Preto in the period of January of 1998 to December of 2005. Conclusion: Our study concluded that the cyclin D1 is related with small tumors and well differentiated and hormone-sensitive tumors. The protein p21 is relates with small tumors, initial stage tumors, low grade tumors and hormone-sensitive tumors. The expression of cyclin D1 in the tumor before the treatment failed to predict response to the neo-adjuvant chemotherapy. However, the presence of the cyclin D1 in the residual tumor andthe protein p21 before the treatment and in the residual tumors suggest improvement in the disease- free survival and overall survival.

Made available in DSpace on 2014-08-20T13:32:47Z (GMT). No. of bitstreams: 1 dissertacao_eduarda_schultze.pdf: 1903452 bytes, checksum: 1fd6d0e0478c9c31687ae8d7882532ea (MD5) Previous issue date: 2013-02-26 / Retinoid derivatives and analogs have been widely studied as antitumor agents due to their effects on cell proliferation and differentiation. Tretinoin (TT), also known as retinoic acid is a retinoid derivative that has been used as an adjuvant in the treatment of acute promyelocytic leukemia with excellent rates of remission. This compound has antiproliferative activity in various tumor types. However, non small cell lung cancer in general exhibit strong resistance to the effects of TT, which may be related to the deficiency in the cellular up-take of TT in that cell type. A strategy to enhance the antiproliferative activity of TT is to increase the cellular internalization of the compound through carriers such as liposomes or other vesicles or nanospheres or nanocapsules. Here we evaluated TT lipid-core nanocapsules (TT-LCNC) for their power to inhibit growth, induce apoptosis and interfere with the cell cycle of lung adenocarcinoma, A549 cell line, which is resistant to treatment with TT. The results showed that TT-LCNC was able to overcome the cellular resistance to treatment with TT, reducing cell viability and inducing apoptosis, upregulation of P21 and cell cycle arrest in G1 phase. / Derivados e análogos retinóides têm sido largamente estudados como agentes antitumorais devido a seus efeitos sobre a proliferação e diferenciação celular. Tretinoína (TT), também conhecida como ácido retinóico é um derivado retinóide que tem sido usado como adjuvante no tratamento de leucemia promielocítica aguda com excelentes índices de remissão da doença. Este composto exerce atividade antiproliferativa em diversos tipos de tumores. Entretanto, células de adenocarcinoma de pulmão humano em geral exibem uma forte resistência aos efeitos da tretinoína, a qual pode estar relacionada com a deficiência na internalização celular de tretinoína nesse tipo de célula. Uma estratégia para aumentar a atividade antiproliferativa de tretinoína é aumentar a captação celular do composto através de carreadores como lipossomas ou outras vesículas como nanocápsulas ou nanoesferas. Neste trabalho nanocápsulas de núcleo lipídico contendo tretinoína (TT-LCNC) foram avaliadas quanto ao seu potencial de inibir o crescimento, induzir a apoptose e interferir com o ciclo celular de células de adenocarcinoma de pulmão, linhagem A549, resistentes ao tratamento com TT livre. Os resultados demonstraram que TT-LCNC foi capaz de superar a resistência celular ao tratamento com TT, reduzindo a viabilidade celular e induzindo apoptose, superexpressão de P21 e parada do ciclo celular em G1.

Die zelluläre Antwort auf einen spezifischen Stimulus wird nicht nur durch den Stimulus selbst, sondern auch von dem Zustand der Zelle bestimmt. Um ein tieferes Verständnis für die Variabilität in einer Zellpopulation zu gewinnen, ist es notwendig, die verschiedenen zellulären Antworten mit definierten zellulären Zuständen zu verbinden. In dieser Arbeit wurde ein System etabliert, welches es ermöglicht, die zelluläre Antwort auf DNA-Schäden und den Einfluss unterschiedlicher zellulärer Zustände zu studieren sowie die zu Grunde liegenden molekularen Mechanismen zu identifizieren. Im Zuge dessen wurde eine auf CRISPR/Cas9 basierende Methode entwickelt, mit der Fluoreszenzreporter für endogene Signalproteine in nicht transformierten Brustepithelzellen (MCF10A) generiert wurden. Anhand dieses Reportersystems konnte durch time-lapse Mikroskopie die Dynamik des Tumorsuppressors p53 und eines seiner Zielgene, des Zellzyklusinhibitors p21, verfolgt werden. Dabei wurde deutlich, dass die p21 Antwort der einzelnen Zellen auf DNA-Schäden sehr heterogen ausfällt. Über eine Form-basierte Gruppierungsmethode wurden vier verschiedene Subpopulationen mit charakteristischen p21 Dynamiken identifiziert. Um den Einfluss der Zellzyklusphase zu untersuchen, wurde die Zellteilung vor Bestrahlung analysiert und so Rückschlüsse auf die initiale Zellzyklusphase gezogen. 24h nach Bestrahlung wurde ein EdU labeling durchgeführt und der Zellzyklus mittels semi-supervised Klassifizierung bestimmt. Durch Einführen einer Mutation in der Bindedomäne von p21 wurde gezeigt, dass proliferating cellular nuclear antigen (PCNA) für die Heterogenität der p21 Antwort verantwortlich ist. Alles in allem bietet mein Projekt eine Pipeline, um auf Einzelzellebene zu erforschen, wie zelluläre Antworten durch den Zellzyklus beeinflusst werden. Dieser Ansatz könnte zukünftig Anwendung in der Erforschung von Medikamentenresistenz finden, zumal zelluläre Heterogenität in der Tumortherapie zu fractional killing führt. / The cellular response to a given stimulus is not only governed by the stimulus itself, but also depends on the state of the cells. However, it remains obscure how cellular states influence cell fate decisions. In this thesis, I established a framework to study how the cellular response to DNA damage is affected by varying cell states and to identify the underlying molecular mechanisms. To this end, I generated fluorescent reporters using CRISPR/Cas9 in non-transformed breast epithelial cells (MCF10A) and measured the dynamics of the tumor suppressor p53 and one of its target genes, the cell cycle inhibitor p21 using time-lapse microscopy. I found DNA damage induced highly diverse p21 dynamics in individual cells. A shape-based clustering identified four subpopulations of characteristic p21 dynamics. To examine the source of variability, I analyzed initial cell cycle states by monitoring cell division prior to damage, and determined final cellular state by EdU labelling and a semi-supervised classification 24h post damage. The results suggested that p21 dynamics depend on cell cycle phases and determine cell cycle progression. Furthermore, proliferating cellular nuclear antigen (PCNA)--a cell cycle dependent factor-- was shown to determine p21 heterogeneity using a mutant p21 deficient in interaction with PCNA. Overall, my project provides a pipeline to study at the single cell level how cellular response is affected by cellular states. Considering that cellular heterogeneity leads to fractional killing in tumor therapies, this approach also suggests future application on studying drug-resistance in cancer therapy.