Infecção persistente por tipos oncogênicos de papilomavírus humano (HPV) é considerada como o principal fator de risco para desenvolvimento de carcinoma invasivo do colo uterino (CCU) e de lesões intraepiteliais cervicais (SIL). Fatores genéticos do hospedeiro, como o polimorfismos de genes HLA (human leukocyte antigen), também têm sido implicados na suscetibilidade a estas patologias e à infecção por (HPV), como observado em diversos estudos caso-controle. Neste estudo investigou-se em uma coorte de mulheres (Ludwig-McGill cohort) se a variabilidade dos genes HLA-DRB1 e -DQB1 influenciam na história natural das infecções por HPV e no risco de SIL. A tipificação de DRB1 e DQB1 foi realizada em 620 amostras provenientes de um estudo epidemiológico prospectivo. A positividade para HPV foi testada em amostras da mesma paciente coletadas a cada 4 meses, obtidos durante o primeiro ano de seguimento, enquanto os resultados de citologia perfazem os 2 primeiros anos de seguimento. Infecções persistentes de curta ou longa duração foram definidas como 2 e 3 resultados consecutivos positivos para o mesmo tipo de HPV, respectivamente. As associações foram estimadas através de razões de chance e intervalos de confiança de 95%, ajustadas para potenciais fatores de confusão. Os resultados obtidos indicam que a prevalência da infecção por HPV e o risco de persistência variam dependendo do haplótipo HLA. O haplótipo DRB1*0301-DQB1*0201 mostrou-se protetor contra a infecção por HPV, e DRB1*1102-DQB1 *0301 contra infecções persistentes. Já os haplótipos DRB1*1601-DQB1*0502 e DRB1 *0807-DQB1*0402 foram fatores de risco para infecções persistentes por HPV. Não foi observada uma forte concordância entre risco de infecção por HPV e risco de SIL associados a determinado HLA, em parte porque o número de pacientes com SIL foi um fator limitante neste estudo. Um risco aumentado de SIL, independente da infecção por HPV, foi associado com DRB1*0301 e DR12. Portadoras de DR4 e DQB1*0601 tiveram uma maior probabilidade de desenvolver SIL e HSIL, respectivamente. Uma associação negativa entre o alelo DQB1*0301 e HSIL foi verificada. Análise do dimorfismo na posição 86 da cadeia β de HLA-DR mostrou que valina nesta posição tem um efeito protetor para prevalência e persistência de infecção por HPV, e maior risco de SIL no grupo com infecções transitórias por HPV. Em outra análise, investigamos a distribuição de grupos alélicos de DRB1 em uma série independente de amostras provenientes de pacientes com CCU. Observamos um risco diminuído de desenvolvimento de CCU associado a DR3. Por outro lado, DR4 e DR8/12 mostraram-se fatores de risco para o CCU nesta população. Estes resultados sugerem que o polimorfismo de HLA desempenha um papel na história natural das infecções por HPV, SIL e CCU. Também analisamos respostas linfoproliferativas em pacientes com CCU, contra peptídeos derivados de E6 e E7 de HPV16. As respostas positivas foram mais freqüentes contra peptídeos de E6 do que E7. Não observamos resposta contra um peptídeo ou região em particular. Parte desta diversidade nas respostas linfoproliferativas pode ser relacionada com o polimorfismo de genes HLA e seu papel na seleção de epítopos. / Persistent infection with oncogenic human papillomavirus (HPV) is the major risk factor for the development of malignant lesions in the uterine cervix. Host factors have also been implicated in the pathogenesis of these diseases. Associations between human leukocyte antigen (HLA) polymorphisms and cervical cancer, precursor lesions or HPV infections have been reported by case-control studies in several populations. This study investigated through cohort analysis if human leukocyte antigen (HLA)-DRB1 and DQB1 variability is related to human papillomavirus (HPV) infection and squamous intraepithelial lesions (SIL) prevalence and persistence. HLA-DRB1 and DQB1 genes were typed in 620 samples from the Ludwig-McGill cohort. HPV positivity was tested in specimens collected every 4 months during the first year of follow-up. Persistent and long-term infections were defined as at least 2 or 3 consecutive positive results for the same HPV type, respectively. Analysis of SIL included data obtained during the two first years of follow-up. The magnitudes of associations were estimated by unconditional logistic regression analysis adjusted for potential confounders. Certain HLA alleles and haplotypes were associated with HPV either HPV prevalence or persistence. The DRB1*0301-DQB1*0201 haplotype was associated with a lower risk for HPV infection and DRB1*1102-DQB1*0301 for HPV persistence. DRB1*1601-DQB1*0502 and DRB1*0807-DQB1*0402 were associated with a increased risk for persistent HPV infection. It was not observed a strong concordance between the associations verified for HPV prevalence/persistence and SIL, possibly due to the limited number of SIL specimens. A higher risk for SIL, independent of HPV infection, was observed for DRB1*0301 and DR12. DR4 and DQB1*0601 carriers showed a higher frequency of SIL and HSIL, respectively. A negative association between DQB1*0301 and HSIL was verified. Valine at position 86 of the DRβ chain was associated with reduced risks of HPV positivity and persistence, as compared to glycine carriers. However, valine carriers had a higher risk of SIL if transiently infected by HPV. We also analyzed an independent sample of patients with invasive cervical, and a protective effect was observed for DR3. On the other hand, DR4 and DR8/12 were associated with a higher risk for cervical cancer in this population. Our results suggest that HLA class II polymorphisms and pocket 1 profile are involved in clearance and maintenance of HPV infection and the risk of SIL and CCU, consistent with the hypothesis that genetic background is important in the natural history of HPV infections and associated lesions. We also analyzed lymphoproliferative responses against HPV16 E6 and E7 peptides, in patients with invasive cervical cancer. Lymphoproliferative responses were more frequent for E6 peptides than for E7 peptides. The responses were not restricted to a particular peptide, which is expected based on HLA variability observed among patients.

The p53 transcription factor responds to various cellular stressors by regulating the expression of numerous target genes involved in cellular processes such as cell cycle arrest, apoptosis, and senescence. As these downstream pathways are harmful to the growth and development of normal cells when prolonged or deregulated, p53 activity needs to be under tight regulatory control. The Mdm2 oncoprotein is the chief negative regulator of p53, and many mouse models have demonstrated that absence of Mdm2 expression leads to constitutive p53 activation in a variety of cell types. While unregulated p53 can be deleterious to cells, functional p53 is essential for tumor suppression, as many human cancers harbor p53 mutations and p53 knockout mice rapidly develop spontaneous tumors. Therefore, the mechanisms that control p53 regulation by Mdm2 are critical to ensure p53 activity in the appropriate cellular context. Many genetically engineered mouse models have been created to analyze p53 and Mdm2 functions and these studies have yielded valuable insights into their physiological roles. This dissertation will describe the generation and characterization of novel mutant Mdm2 mouse models and their use to interrogate the roles of p53-Mdm2 signaling in tissue homeostasis and cell stress responses. Deletion of Mdm2 in epidermal progenitor cells of the skin and hair follicles resulted in progressive hair loss and decreased skin integrity, phenotypes that are characteristic of premature aging. Furthermore, p53 protein levels, p53 target gene expression, and cellular senescence were all upregulated in the skins of these mice, and epidermal stem cell numbers and function were diminished. These results indicate that Mdm2 is necessary to limit p53 activity in adult tissues to ensure normal stem cell function. Additional mouse models used to determine the role of Mdm2 phosphorylation will also be presented. DNA damage triggers an extensive cellular response, including activation of the ATM kinase. ATM activity is necessary for p53 protein stabilization and, therefore, p53 activation, but in vivo evidence suggests that phosphorylation of p53 itself had little effect on p53 stability. ATM was previously shown to phosphorylate MDM2 at serine residue 395 (394 in mice), and we generated knock-in mutant mouse models to study the role of this posttranslational modification in vivo. Absence of this phosphorylation site led to greatly diminished p53 stability and function in response to γ-irradiation and increased spontaneous tumorigenesis in mice. Conversely, a phosphomimic model demonstrated prolonged p53 activation in cells treated with γ-irradiation, which revealed that phosphorylation of this Mdm2 residue controls the duration of the DNA damage response. Therefore, these mouse models have uncovered new roles for the p53-Mdm2 regulatory axis in vivo and will be useful reagents in future studies of posttranslational modifications in oncogene and DNA damage-induced tumorigenesis.

Yes / Bone morphogenetic proteins (BMPs) play essential roles in the control of skin development, postnatal tissue remodelling and tumorigenesis. To explore whether some of the effects of BMP signalling are mediated by microRNAs, we performed genome-wide microRNA (miRNA) screening in primary mouse keratinocytes after BMP4 treatment. Microarray analysis revealed substantial BMP4-dependent changes in the expression of distinct miRNAs, including miR-21. Real-time PCR confirmed that BMP4 dramatically inhibits miR-21 expression in the keratinocytes. Consistently, significantly increased levels of miR-21 were observed in transgenic mice overexpressing the BMP antagonist noggin under control of the K14 promoter (K14-noggin). By in situ hybridization, miR-21 expression was observed in the epidermis and hair follicle epithelium in normal mouse skin. In K14-noggin skin, miR-21 was prominently expressed in the epidermis, as well as in the peripheral portion of trichofolliculoma-like hair follicle-derived tumours that contain proliferating and poorly differentiated cells. By transfecting keratinocytes with a miR-21 mimic, we identified the existence of two groups of the BMP target genes, which are differentially regulated by miR-21. These included selected BMP-dependent tumour-suppressor genes (Pten, Pdcd4, Timp3 and Tpm1) negatively regulated by miR-21, as well as miR-21-independent Id1, Id2, Id3 and Msx2 that predominantly mediate the effects of BMPs on cell differentiation. In primary keratinocytes and HaCaT cells, miR-21 prevented the inhibitory effects of BMP4 on cell proliferation and migration. Thus, our study establishes a novel mechanism for the regulation of BMP-induced effects in the skin and suggests miRNAs are important modulators of the effects of growth factor signalling pathways on skin development and tumorigenesis.

<p>UVOD: Karcinom kolona (KK) je velik javnozdravstveni problem usled visoke incidence i stope mortaliteta. Kod KK je stadijum bolesti najvažniji pojedinačni nezavisni faktor prognoze. U prisustvu nepovoljnih prognostičkih parametara, u koje spadaju visok histolo&scaron;ki gradus, ileus, limfo-vaskularna i perineuralna invazija, nakon potencijalno kurativne operacije se kod pacijenata u stadijumu II indikuje primena adjuvantne hemioterapije koja ima pozitivan uticaj na ukupno preživljavanje i na produženje perioda bez bolesti. Međutim, relapsi bolesti nastaju kod nekih bolesnika bez negativnih prognostičkih faktora, &scaron;to ukazuje na moguće postojanje drugih tkivnih faktora lo&scaron;e prognoze. U novije vreme se sve veća pažnja posvećuje fenomenu tumorskog pupljenja koje predstavlja pojavu tumorskih pupoljaka (TP), odnosno oligocelularnih grupa tumorskih ćelija koje se na invazivnom frontu tumora odvajaju od glavne tumorske mase. Ove tumorske ćelije poprimaju fenotip mezenhimnih ćelija i stiču sposobnost ameboidnog kretanja kroz ekstracelularni matriks, uz pomoć citoplazmatskih podija koje se na dvodimenzionalnim histolo&scaron;kim rezovima vizualizuju kao citoplazmatski pseudofragmenti (CPF). Značaj gustine TP i CPF je jo&scaron; uvek nedovoljno ispitan, ali postoje indicije da se radi o moćnom prediktoru biolo&scaron;kog pona&scaron;anja tumora. CILJ: Cilj je bio da se ispita zavisnost dužine perioda bez relapsa, veličine primarnog tumora, gustine peritumorske limfocitne infiltracije i konfiguracije tumorske margine od gustine TP i CPF kod bolesnika sa KK u stadijumu II. METODOLOGIJA: Istraživanjem je obuhvaćeno 114 bolesnika operisanih od KK u stadijumu II na Institutu za onkologiju Vojvodine, bez nepovoljnih prognostičkih faktora i bez indikacija za primenu adjuvantne hemioterapije. Mikroskopskom analizom rutinskih histolo&scaron;kih i imunohistohemijskih preparata utvrđivana je gustina TP i CPF, koja je zatim korelirana sa vremenom pojave relapsa, veličinom primarnog tumora, gustinom peritumorske limfocitne infiltracije i konfiguracijom tumorske margine. REZULTATI: Velika gustina TP i/ili CPF nađena je kod 45 tumora (39,5%). U ovoj grupi se relaps dogodio kod 26 bolesnika (57,8%). U grupi bolesnika sa malom gustinom TP/CPF relaps je registrovan u 4 slučaja (5,8%). Poređenje krivih preživljavanja pokazalo je da je verovatnoća relapsa značajno veća ako se u tumoru nalazi velika gustina TP/CPF (p&lt;0,0001). Tumori sa velikom gustinom TP/CPF su imali najveći prečnik koji je varirao u rasponu od 25 do 100 mm, dok su tumori sa malom gustinom TP/CPF bili najvećeg prečnika od 20 do 110 mm (p=0,6744). Intenzitet peritumorskog limfoidnog odgovora je bio velik kod 13 tumora sa velikom gustinom TP/CPF (28,9%) i kod 17 tumora sa malom gustinom TP/CPF (24,6%), p=0,7747. Konfiguracija tumorske margine je bila infiltrativna u svim tumorima sa velikom gustinom TP/CPF, kao i kod 42 tumora sa malom gustinom TP/CPF (60,9%). ZAKLJUČAK: Velika gustina TP/CPF je nezavisan tkivni indikator lo&scaron;e prognoze kod bolesnika sa KK u stadijumu II, koji je ne korelira ni sa veličinom primarnog tumora ni sa intenzitetom peritumorskog limfoidnog odgovora. Velika gustina TP/CPF nije kompatibilna sa ekspanzivnom konfiguracijom tumorske margine, ali infiltrativna konfiguracija tumorske margine nije prediktor velike gustine TP/CPF.</p> / <p>INTRODUCTION: Colonic carcinoma (CC) is a serious public health problem due to its high incidence and mortality rate. Stage is the single most important independent prognosticator in patients with CC. In the presence of indicators of poor prognosis, including high histologic grade, ileus, lympho-vascular invasion and perineural invasion, there is a need for adjuvant chemotherapy after a potentially curative operation in patients with stage II CC, because the therapy improves both overall survival and disease-free survival. However, some patients with no documented poor prognostic factors suffer recurrences, which indicates that there may be some other tissue features that confer poor prognosis. In the recent publications there is an increasing interest in the phenomenon of tumor budding, a term assigned to the presence of small groups of discohesive tumor cells at the invasive front of the tumor &ndash; tumor buds (TB&#39;s). These cells acquire mesenchymal phenotype and gain the ability to migrate through the extracellular matrix by means of cytoplasmic extrusions which are visible on the two-dimensional immunohistologic sections and are called cytoplasmic pseudofragments (CPF&#39;s). Significance of density of TB&#39;s and CPF&#39;s is still to be evaluated, but the pool of evidence suggests that this is a powerful predictor of biologic behaviour of CC. AIM: The aim of this study was to determine the influence of density of TB&#39;s and CPF&#39;s on the risk of recurrence in patients with stage II CC. This research also attempted to establish whether there is a correlation between the density of TB&#39;s and CPF&#39;s and several other morphologic features such as tumor diameter, peritumoral lymphocytic response and the configuration of the tumor margin. METHODS: 114 patients with stage II CC were enrolled in the study. All the patients received surgery at the Institute of Oncology in Sremska Kamenica and no patient had indication for adjuvant chemotherapy. Microscopic analysis of routine histologic and immunohistochemical slides was performed to establish the density of TB&#39;s and CPF&#39;s, to estimate the intensity of the peritumoral lymphocytic response and to determine the configuration of the tumor margin. RESULTS: High density of TB&#39;s and/or CPF&#39;s was found in 45 tumors (39.5%). In this group recurrence occured in 26 patients (57.8%). In the group of patients with low density of TB/CPF in the tumor tissue 4 patients relapsed (5.8%). Comparison of survival curves showed that the probability of recurrence was significantly greater if the density of TB/CPF&#39;s was high (p&lt;0.0001). Tumors with high density of TB/CPF&#39;s ranged from 25 to 100 mm in greatest diameter, while those with low density measured from 20 to 110 mm (p=0.6744). Intensity of peritumoral lymphocytic response was high in 13 tumors with high density of TB/CPF&#39;s (28.9%) and in 17 tumors with low density of TB/CPF&#39;s (24.6%), p=0.7747. All tumors with high density of TB/CPF&#39;s and 42 tumors with low density of TB/CPF&#39;s (60.9%) had infiltrative configuration of tumor margin. CONCLUSION: High density of TB/CPF&#39;s is an independent indicator of poor prognosis in patients with stage II CC and it correlates neither with tumor diameter nor with intensity of peritumoral lymphocytic response. High density of TB/CPF&#39;s is not compatible with the expansive configuration of tumor margin, but the infiltrative configuration of tumor margin is not a predictor of high density of TB/CPF&#39;s.</p>

Infiltration of myeloid cells in the tumor microenvironment is often associated with enhanced angiogenesis and tumor progression, resulting in poor prognosis in many types of cancer. The polypeptide chemokine PK2 (Bv8, PROK2) has been shown to regulate myeloid cell mobilization from the bone marrow, leading to activation of the angiogenic process, as well as accumulation of macrophages and neutrophils in the tumor site. Neutralizing antibodies against PK2 were shown to display potent anti-tumor efficacy, illustrating the potential of PK2-antagonists as therapeutic agents for the treatment of cancer. In this study we demonstrate the anti-tumor activity of a small molecule PK2 antagonist, PKRA7, in the context of glioblastoma and pancreatic cancer xenograft tumor models. For the highly vascularized glioblastoma, PKRA7 was associated with decreased blood vessel density and increased necrotic areas in the tumor mass. Consistent with the anti-angiogenic activity of PKRA7 in vivo, this compound effectively reduced PK2-induced microvascular endothelial cell branching in vitro. For the poorly vascularized pancreatic cancer, the primary anti-tumor effect of PKRA7 appears to be mediated by the blockage of myeloid cell migration/infiltration. At the molecular level, PKRA7 inhibits PK2-induced expression of certain pro-migratory chemokines and chemokine receptors in macrophages. Combining PKRA7 treatment with standard chemotherapeutic agents resulted in enhanced effects in xenograft models for both types of tumor. Taken together, our results indicate that the anti-tumor activity of PKRA7 can be mediated by two distinct mechanisms that are relevant to the pathological features of the specific type of cancer. This small molecule PK2 antagonist holds the promise to be further developed as an effective agent for combinational cancer therapy. / Dissertation

Alterações epigenéticas, como metilação do DNA e modificações pós traducionais em histonas, tem importante papel na carcinogênese mamária. A modulação de eventos epigenéticos constitui relevante alvo terapêutico, devido ao seu caráter reversível. Experimentalmente, o ácido docosahexaenoico (DHA), um membro da família dos ácidos graxos ômega-3, é capaz de diminuir proliferação, induzir morte celular e diminuir o potencial invasivo de células tumorais de mama. No entanto, os mecanismos antitumorais do DHA e sua capacidade de modular eventos epigenéticos ainda não estão totalmente elucidados. Nosso objetivo foi verificar, in vitro, a ação do DHA em eventos epigenéticos em diferentes linhagens de carcinoma mamário humano. Três linhagens celulares de câncer de mama (MDA-MB-231, SKBR-3 e MCF-7) foram tratadas durante 72 horas com 100 ?M de DHA ou etanol (controle). As modificações pós traducionais em histonas, acetilação no resíduo de lisina 9 da histona 3 (H3K9ac) e no resíduo 16 da histona 4 (H4K16ac), bem como trimetilação no resíduo de lisina 9 da histona 3 (H3K9me3) e no resíduo de lisina 27 da histona 3 (H3K27me3) foram avaliadas pela técnica de western blot. A análise da expressão do genes RASSF1A, DNMT1, DNMT3A e DNMT3B foi feita pela técnica da reação em cadeia da polimerase quantitativa via transcriptase reversa (RT-qPCR). A avaliação do padrão de metilação de região promotora do gene RASSF1A foi realizada pela técnica de reação em cadeia da polimerase metilação específica (MS-PCR). Foram também analisadas as fases do ciclo celular por citometria de fluxo. Comparado ao controle, o DHA induziu a acetilação no resíduo 16 da histona 4 (H4K16ac) nas linhagens MCF7 (p = 0,04) e MDA-MB-231 (p = 0,03). Observamos que a H3K9me3 foi parcialmente inibida nas linhagens MDA-MB-231 e SKBR-3, após o tratamento com DHA, mas sem alcançar valor estatisticamente significante. Encontramos também diminuição dos níveis de H3K27me3 após o tratamento com DHA nas três linhagens estudadas, porém não foi estatisticamente significativo. O DHA aumentou a expressão do gene RASSF1A na linhagem MCF-7 (1,98 vezes, p = 0,03), mas não nas linhagens MDA-MB-231 e SKBR-3. Não houve mudanças estatisticamente significativas na expressão dos genes DNMT1, DNMT3A e DNMT3B. As análises qualitativas da metilação demonstraram que a região promotora analisada do gene RASSF1A apresentou-se hipermetilada nas três linhagens celulares. Após o tratamento com DHA, houve tendência de desmetilação na região promotora do RASSF1A na linhagem MCF-7 e SKBR3, mas não na linhagem MDA-MB-231. Não houve diferença significativa na porcentagem de morte e distribuição das células MDA-MB-231, SKBR-3 e MCF-7 nas diferentes fases do ciclo celular após tratamento com DHA. Em conclusão, o DHA pode atuar em mecanismos epigenéticos e, ainda, reativar o gene supressor de tumor, como RASSF1A, anteriormente silenciado por hipermetilação, em células MCF-7. Espera-se que esses resultados contribuam para melhor compreensão do potencial papel anticâncer do DHA no câncer de mama / Epigenetic changes, such as DNA methylation and post-translational histone modifications, play an important role in mammary tumorigenesis. Epigenetic events are important as therapeutic targets, because of its reversible nature. Experimentally, docosahexaenoic acid (DHA), a member of the omega-3 fatty acids family, can reduce proliferation, induce apoptosis and decrease the invasive potential of breast tumor cells. However, the antitumor mechanism of DHA and its ability to modulate epigenetic events are not completely understood. Our objective was to verify, in vitro, the action of DHA in epigenetic events related to transcriptional reactivation of tumor suppressor gene, such as RASSF1A, in different human breast cancer cell lines. Three breast cancer cell lines (MCF-7, MDA-MB-231, SKBR-3) were treated with DHA (100 ?M) or vehicle (ethanol) for 72 hours. Western blot was used to analyze histone modification, as histone H3 lysine 9 (H3K9ac) and histone H4 lysine 16 (H4K16ac) acetylation, H3K9 trimethylation (H3K9me3) and H3K27 trimethylation (H3K27me3). Real time quantitative PCR (RT-qPCR) was performed for gene expression quantification of RASSF1A, DNMT1, DNMT3A and DNMT3B. DNA methylation of the promoter region of RASSF1A was evaluated by methylation specific PCR (MS-PCR). Moreover, we evaluated the phases of the cell cycle by flow cytometry. Compared to control cells, DHA induced H4K16ac in MCF-7 (p=0.04) and MDA-MB-231 (p=0.03). We observed that H3K9me3 was partially inhibited in MDA-MB-231 and SKBR-3 cells, after treatment with DHA, but did not reach a statistically significant value. We also found decreased levels of H3K27me3 after treatment with DHA in the three cell lines studied, but not statistically significant. DHA increased RASSF1A expression on MCF-7 (1.98 fold; p=0.03), but not in MDA-MB-231 and in SKBR-3 cells. There were no statistically significant changes in expression of genes DNMT1, DNMT3A and DNMT3B. These three breast cancer cells lines show methylation in specific region of RASSF1A promoter. DHA treatment increased RASSF1A promoter region hypomethylation in MCF-7 and SKBR-3. No significant difference was observed in the percentage of cell death nor cell distribution of MDA-MB-231, SKBR-3 and MCF-7 at different stages of the cell cycle after treatment with DHA. In conclusion, we suggest that DHA may act beneficially in epigenetic mechanisms and reactivation of tumor suppressor gene, RASSF1A as previously silenced by hypermethylation. It is hoped that these results can contribute to better understanding of the anticancer role of DHA in breast cancer

Made available in DSpace on 2014-07-29T15:30:36Z (GMT). No. of bitstreams: 1 Dissertacao Andrea Alves Ribeiro.pdf: 1577076 bytes, checksum: 24bc7ace843786b03ff879da0df4f7aa (MD5) Previous issue date: 2009-12-15 / Human papillomavirus (HPV) is considered the central etiological agent involved in the genesis of cervical cancer. The HPV viruses are classified according to their biological niche, oncogenic potential and phylogenetic position. According to the criteria established by the International Committee on Taxonomy of Viruses (ICTV), the various groups of human papillomaviruses that infect the female genital tract are classified phylogenetically in the Alphapapillomavirus genus, including species classified among phylogenetic species 1 and species 15. The main high risk HPV are classified in species 9 (HPV 16, 31, 33, 35, 52, 58, 67), and in species 7 (18, 39, 45, 59, 56, 66, 68 and 70). HPV 16 is the most prevalent type irrespective of diagnosis, principally in more severe lesions. Coinfection with multiple-types HPV is a common finding of many molecular studies. Some HPV types might interact or act synergistically to induce progression. Few studies have investigated the interactions of viral genotypes or species in multiple-type HPV infections. Therefore, the objective of this study was to evaluate the effect of single or multiple-types HPV infections considering also the phylogenetic groups on the prevalence and severity of cervical intraepithelial neoplasia (CIN) among women undergoing colposcopy following a abnormal cervical smear. Methodology: In this analysis, 198 women attending at the colposcopic clinic, because of an abnormal cervical smear were included. Colposcopy was carried out in all cases and biopsies were done in 193 of 198 women included. All specimens were tested for 27 HPV genotypes by Roche s polymerase chain reaction reverse line blot assay. Results: The overall prevalence of HPV in women with an abnormal cervical smear was 86% (171/198). Of the total of HPV-positive women, 45% (77/171) were infected with HPV 16 as a single or multiple-type infections. HPV 31 and 35 were, respectively, the second and third most prevalent types. The prevalence of HPV 16 in high grade cervical intraepithelial neoplasia (CIN2/3) was 52% (40/76) and it was detected in 88.8% (8/9) in cases of invasive carcinoma. The prevalence of type 31 and 35 in high grade CIN was respectively 10.5% (8/76) and 6.6% (5/76). Single HPV infection for any type was significantly associated with neoplastic diagnosis. High grade neoplastic diagnosis (&#8805; CIN2) was significantly associated with HPV 16 in single or multiple infections. Also, there was significantly association between HPV 16 and others types of specie 9 and high grade neoplastic diagnosis, but no association was observed considering the HPV 16 and other of groups of species 7 or others types. Conclusion: These results indicated that the type 16 is the most important predictor of high grade cervical neoplasia. Multiple-type infections are predictors of high grade cervical neoplasia when the type 16 is present. / O Papilomavírus humano (HPV) é considerado o agente etiológico central envolvido na gênese do câncer cervical. O vírus HPV é classificado de acordo com seu nicho biológico, potencial oncogênico e classificação filogenética. De acordo com os critérios estabelecidos pelo Comitê Internacional de Taxonomia dos Vírus (ICTV), os diversos tipos de HPV que infectam o trato genital feminino são classificados filogeneticamente no gênero Alphapapillomavirus. Esta classificação inclui espécies filogenéticas classificadas entre a espécie 1 e a espécie 15, dentre as quais, as de maior interesse em relação ao potencial carcinogênico são a espécie 9 (HPV 16, 31, 33, 35, 52, 58, 67) e a espécie 7 (18, 39, 45, 56, 59, 66, 68, 70). O HPV 16 é tipo o mais predominante, independente do diagnóstico, presente principalmente nas lesões cervicais mais graves. A co-infecção com múltiplos tipos de HPV é um achado comum em muitos estudos moleculares, contudo, as interações dos genótipos virais ou espécies envolvidas nas infecções por múltiplos tipos de HPV têm sido pouco analisadas. Portanto, o objetivo deste estudo foi avaliar o efeito das infecções simples ou por múltiplos tipos de HPV, considerando também os grupos filogenéticos, sobre a prevalência e a gravidade das neoplasias cervicais. Metodologia: Este estudo de corte transversal incluiu 198 mulheres encaminhadas ao Ambulatório de Colposcopia da Santa Casa de Misericórdia de Goiânia por exame citopatológico anormal. Todas as mulheres foram esclarecidas quanto aos objetivos de estudo e assinaram o termo de consentimento livre e esclarecido. A colposcopia foi realizada em todos os casos e a biópsia em 193 das 198 mulheres incluídas. As amostras foram testadas para 27 genótipos de HPV, por reação em cadeia da polimerase (PCR); em seguida foi realizada a hibridização reversa em pontos da Roche Diagnósticos. Resultados: A prevalência de HPV em mulheres encaminhadas por exame citopatológico anormal foi de 86% (171/198). Do total de mulheres HPV-positivas, 45% (77/171) estavam infectadas por HPV 16 em infecções simples e múltiplas. Os tipos de HPV 31 e 35 foram respectivamente, o segundo e o terceiro mais prevalentes. A prevalência do HPV 16 foi de 52% (40/76) nas neoplasias intra-epiteliais cervicais de alto grau (NIC 2/3) e de 88,8% (8/9) nos casos de carcinomas invasivos. As prevalências dos tipos 31 e 35 em neoplasias intra-epiteliais cervicais de alto grau (NIC 2/3) foram de 10,5% (8/76) e 6,6% (5/76), respectivamente. A infecção simples por qualquer tipo de HPV foi significativamente associada com diagnósticos neoplásicos de alto grau (&#8805; NIC 2). Os diagnósticos neoplásicos de alto grau (&#8805; NIC 2) foram significativamente associados com o HPV 16 em infecções simples ou múltiplas, mesmo depois de ajustado pela positividade para DNA de HPV. Houve significativa associação entre o HPV 16 e outros tipos da espécie 9 e os diagnósticos neoplásicos de alto grau (&#8805; NIC 2), mas não foi observada associação, considerando o HPV 16 e outros tipos da espécies 7 ou outros tipos de HPV. Conclusão: Estes resultados indicam que o HPV 16 parece ser o mais importante preditor de diagnósticos neoplásicos de alto grau. As infecções múltiplas são preditoras das neoplasias cervicais de alto grau quando o HPV 16 está presente.

Alterações epigenéticas, como metilação do DNA e modificações pós traducionais em histonas, tem importante papel na carcinogênese mamária. A modulação de eventos epigenéticos constitui relevante alvo terapêutico, devido ao seu caráter reversível. Experimentalmente, o ácido docosahexaenoico (DHA), um membro da família dos ácidos graxos ômega-3, é capaz de diminuir proliferação, induzir morte celular e diminuir o potencial invasivo de células tumorais de mama. No entanto, os mecanismos antitumorais do DHA e sua capacidade de modular eventos epigenéticos ainda não estão totalmente elucidados. Nosso objetivo foi verificar, in vitro, a ação do DHA em eventos epigenéticos em diferentes linhagens de carcinoma mamário humano. Três linhagens celulares de câncer de mama (MDA-MB-231, SKBR-3 e MCF-7) foram tratadas durante 72 horas com 100 ?M de DHA ou etanol (controle). As modificações pós traducionais em histonas, acetilação no resíduo de lisina 9 da histona 3 (H3K9ac) e no resíduo 16 da histona 4 (H4K16ac), bem como trimetilação no resíduo de lisina 9 da histona 3 (H3K9me3) e no resíduo de lisina 27 da histona 3 (H3K27me3) foram avaliadas pela técnica de western blot. A análise da expressão do genes RASSF1A, DNMT1, DNMT3A e DNMT3B foi feita pela técnica da reação em cadeia da polimerase quantitativa via transcriptase reversa (RT-qPCR). A avaliação do padrão de metilação de região promotora do gene RASSF1A foi realizada pela técnica de reação em cadeia da polimerase metilação específica (MS-PCR). Foram também analisadas as fases do ciclo celular por citometria de fluxo. Comparado ao controle, o DHA induziu a acetilação no resíduo 16 da histona 4 (H4K16ac) nas linhagens MCF7 (p = 0,04) e MDA-MB-231 (p = 0,03). Observamos que a H3K9me3 foi parcialmente inibida nas linhagens MDA-MB-231 e SKBR-3, após o tratamento com DHA, mas sem alcançar valor estatisticamente significante. Encontramos também diminuição dos níveis de H3K27me3 após o tratamento com DHA nas três linhagens estudadas, porém não foi estatisticamente significativo. O DHA aumentou a expressão do gene RASSF1A na linhagem MCF-7 (1,98 vezes, p = 0,03), mas não nas linhagens MDA-MB-231 e SKBR-3. Não houve mudanças estatisticamente significativas na expressão dos genes DNMT1, DNMT3A e DNMT3B. As análises qualitativas da metilação demonstraram que a região promotora analisada do gene RASSF1A apresentou-se hipermetilada nas três linhagens celulares. Após o tratamento com DHA, houve tendência de desmetilação na região promotora do RASSF1A na linhagem MCF-7 e SKBR3, mas não na linhagem MDA-MB-231. Não houve diferença significativa na porcentagem de morte e distribuição das células MDA-MB-231, SKBR-3 e MCF-7 nas diferentes fases do ciclo celular após tratamento com DHA. Em conclusão, o DHA pode atuar em mecanismos epigenéticos e, ainda, reativar o gene supressor de tumor, como RASSF1A, anteriormente silenciado por hipermetilação, em células MCF-7. Espera-se que esses resultados contribuam para melhor compreensão do potencial papel anticâncer do DHA no câncer de mama / Epigenetic changes, such as DNA methylation and post-translational histone modifications, play an important role in mammary tumorigenesis. Epigenetic events are important as therapeutic targets, because of its reversible nature. Experimentally, docosahexaenoic acid (DHA), a member of the omega-3 fatty acids family, can reduce proliferation, induce apoptosis and decrease the invasive potential of breast tumor cells. However, the antitumor mechanism of DHA and its ability to modulate epigenetic events are not completely understood. Our objective was to verify, in vitro, the action of DHA in epigenetic events related to transcriptional reactivation of tumor suppressor gene, such as RASSF1A, in different human breast cancer cell lines. Three breast cancer cell lines (MCF-7, MDA-MB-231, SKBR-3) were treated with DHA (100 ?M) or vehicle (ethanol) for 72 hours. Western blot was used to analyze histone modification, as histone H3 lysine 9 (H3K9ac) and histone H4 lysine 16 (H4K16ac) acetylation, H3K9 trimethylation (H3K9me3) and H3K27 trimethylation (H3K27me3). Real time quantitative PCR (RT-qPCR) was performed for gene expression quantification of RASSF1A, DNMT1, DNMT3A and DNMT3B. DNA methylation of the promoter region of RASSF1A was evaluated by methylation specific PCR (MS-PCR). Moreover, we evaluated the phases of the cell cycle by flow cytometry. Compared to control cells, DHA induced H4K16ac in MCF-7 (p=0.04) and MDA-MB-231 (p=0.03). We observed that H3K9me3 was partially inhibited in MDA-MB-231 and SKBR-3 cells, after treatment with DHA, but did not reach a statistically significant value. We also found decreased levels of H3K27me3 after treatment with DHA in the three cell lines studied, but not statistically significant. DHA increased RASSF1A expression on MCF-7 (1.98 fold; p=0.03), but not in MDA-MB-231 and in SKBR-3 cells. There were no statistically significant changes in expression of genes DNMT1, DNMT3A and DNMT3B. These three breast cancer cells lines show methylation in specific region of RASSF1A promoter. DHA treatment increased RASSF1A promoter region hypomethylation in MCF-7 and SKBR-3. No significant difference was observed in the percentage of cell death nor cell distribution of MDA-MB-231, SKBR-3 and MCF-7 at different stages of the cell cycle after treatment with DHA. In conclusion, we suggest that DHA may act beneficially in epigenetic mechanisms and reactivation of tumor suppressor gene, RASSF1A as previously silenced by hypermethylation. It is hoped that these results can contribute to better understanding of the anticancer role of DHA in breast cancer

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-17T21:35:19Z No. of bitstreams: 1 Mario Cezar Saffi Junior.pdf: 600477 bytes, checksum: 389162272a6d7d9eb1d1a097d21a6d9a (MD5) / Made available in DSpace on 2016-05-17T21:35:19Z (GMT). No. of bitstreams: 1 Mario Cezar Saffi Junior.pdf: 600477 bytes, checksum: 389162272a6d7d9eb1d1a097d21a6d9a (MD5) Previous issue date: 2015-01-22 / The cervical cancer is the first cancer of the female genital tract in Brazil and HPV is essential factor for carcinogenesis. The Brazilian program tracking proposes conventional cervical cytology as the primary method to detect cervical cancer, despite its low sensitivity. Risk factors associated with the spread of HPV are despised and not rely on a biomolecular tool that can increase the program offered by the Ministry of Health. The aim of this study was to determine whether the risk factors for cervical cancer may contribute to the conventional cervical cytology to increase diagnostic sensitivity and assess whether the mRNA indoleamine 2,3 dioxygenase (IDO) and mRNA CDKN2A / p16 may increase the diagnostic yield of this neoplasm. The logistic regression analysis was based on clinical variables (risk factors), cytological and biomolecular to seek an association with pathological results. The proportion of explained variance (PVE) for each variable studied was calculated by the formula omega, whereas the sensitivity, specificity, positive predictive value and negative predictive value were calculated by the formulas of Galen and Gambino. We conclude that oral contraceptive showed greater predictive power of high-grade lesions compared to other risk factors, and that both the IDO mRNA as CDKN2A mRNA / p16 may help screening of cervical cancer, either when used alone, or in conjunction with conventional cervical cytology, increasing their sensitivity and maintaining a considerable specificity. / O câncer de colo uterino apresenta-se como a principal neoplasia do trato genital feminino no Brasil, sendo o HPV fator essencial para a carcinogênese. O programa brasileiro de rastreamento propõe a citologia oncológica cervical convencional como principal método para detectar o câncer do colo uterino, apesar da sua baixa sensibilidade. Os fatores de risco associados ao contágio do HPV são desprezados e não contamos com uma ferramenta biomolecular que possa incrementar o programa oferecido pelo Ministério da Saúde. O objetivo desse trabalho foi verificar se os fatores de risco para o câncer de colo uterino podem contribuir com a citologia oncológica cervical convencional para aumentar a sensibilidade diagnóstica e avaliar se o RNAm Indoleamine 2,3 dioxigenase (IDO) e o RNAm CDKN2A/p16 podem incrementar a capacidade diagnóstica dessa neoplasia. A análise de regressão logística foi baseada nas variáveis clínicas (fatores de risco), citológicas e biomoleculares a fim de buscar uma associação com o resultado anatomopatológico. A proporção de variação explicada (PVE) por cada uma das variáveis estudada foi calculada pela fórmula ômega, enquanto que a sensibilidade, especificidade, valor preditivo positivo e o valor preditivo negativo foram calculados pelas fórmulas de Galen e Gambino. Concluímos que o uso do contraceptivo oral mostrou um maior poder de predição de lesões de alto grau em relação aos demais fatores de risco, e que tanto a RNAm IDO quanto o RNAm CDKN2A/p16 poderem auxiliar no rastreamento do câncer de colo uterino, seja quando usados de forma isolada, seja conjuntamente com a citologia cervical convencional, elevando sua sensibilidade e mantendo uma considerável especificidade.

<p>Karcinom debelog creva predstavlja treći uzrok smrnosti od maligniteta kod mu&scaron;karaca i drugi kod žena. Postoji osnovana sumnja da kancerske matične ćelije (KMĆ) imaju veliki značaj u karcinogenezi, invazivnosti, &scaron;irenju i rezistenciji na hemioterapiju primarnog tumora. Njihova identifikacija u primatnom kolorektalnom karcinomu (KRK) putem markera kancerskih matičnih ćelija bi selektovala visokorizičnu grupu bolesnika, omogućila ciljano delovanje na ove ćelije i veću &scaron;ansu za izlečenje. Cilj ovog istraživanja je bio utvrđivanje uticaja prisustva kancerskih matičnih ćelija u primarnom tumoru obolelih od karcinoma kolona na pojavu relapsa bolesti, dužino preživljavanja bez bolesti i sveukupno preživljavanje.&nbsp; Istraživanje je sprovedeno kao prospektivno&minus;retrospektivna randomizovana analitička studija na Klinici za operativnu onkologiju i Službi za patolo&scaron;ko &ndash; anatomsku i laboratorijsku dijagnostiku Instituta za onkologiju Vojvodine u Sremskoj Kamenici u periodu od 2016-2019. godine. U studiju su uključeno 112 bolesnica operisanih na Institutu za onkologiju Vojvodine u periodu od 2007-2012. godine sa patohistolo&scaron;ki potvrđenom dijagnozom primarnog, nemetastatskog (stadijumi I, II i III) KRK. Bolesnici su randomizovani u odnosu na pojavu recidiva bolesti i prisustvo metastaza u regionalnim limfnim čvorovima u odnosu 1:1. Uzorci tumorskog tkiva dobijeni hirur&scaron;kom resekcijom su nakon standardne patohistolo&scaron;ke obrade tretirani primenom monoklonskih antitela na CD44, CD166 i &alpha;-Lgr5. Određivani su prisustvo, intezitet i lokalizacija kancerskih matičnih ćelija (KMĆ) u primarnom tumoru i njihov uticaj na pojavu relapsa bolesti, dužinu preživljavanja bez bolesti i sveukupno preživljavanje u grupi svih bolesnika a potom bolesnika podeljenih prema stadijumu bolesti. Bolesnici u prvom i drugom stadijumu bolesti koji su imali relaps su imali statistički značajno veće prisustvo CD44+ KMĆ u primarnom tumoru. Kod ovih bolesnika je prisutan kraći period preživljavanja bez bolesti kao i kraće sveukupno preživljavanje. Takođe, uočen je statistički značajan uticaj koekspresije CD44/CD166 u KMĆ na pojavu relapsa bolesti, dužinu preživljavanja bez bolesti i sveukupno preživljavanje kod bolesnika u prvom i drugom stadijumu bolesti. Nije uočena statistička značajnost prisustva KMĆ u primarnom tumoru na pojavu relapsa bolesti, dužinu preživljavanja bez bolesti i sveukupno preživljavanje kod bolesnika u trećem stadijumu bolesti. Prisustvo CD166 i &alpha;-Lgr5 obojenih KMĆ nije pokazalo statističku značajnost u pogledu pojave relapsa bolesti, dužine preživljavanja bez bolesti i sveukupnog preživljavanja, kako u grupi svih bolesnika tako i prilikom podele bolesnika na stadijume bolesti.</p> / <p>Colon cancer is the third most common case of death of malignancy in the world. There is justified theory that cancer stemm cells have significant impact on colon cancer tumorogenesis, invasiviness, spread and resistancy on chemotherapy. Identification of colon cancer stem cells in primary tumor by various biological markers would lead to identification of high risk group of patients, target therapy of colon cancer an higher chance to cure. Aim of this study was to determine wether presence of colon cancer stem cells in primary tumour have impact on recurrence, disease free survival (DFS) and overall survival (OS) in patients with colorectal cancer. An randomized, analytical prospective-retrospective study was performed on Clinic for Operative Oncology and Department for Anatomical Pathology of Oncology Institute of Vojvodina in Sremska Kamenica in period of 2016&minus;2019. Study included 112 patient with patohistological proven, non metastatic colon adenocarcinoma who were operated on Oncology Institute of Vojvodina in period of 2007-2012. Patients were randomized by recurrence and presence of metastatic lymph nodes by 1:1 ratio. After standard patohistological preparation, tumour specimens were stained for monoclonal CD44, CD166 and &alpha;-Lgr5 antibody. Presence, intensity of expression and localization of colon cancer stem cells were observed and their impact on relapse, disease free survival and overall survival in group of all patients as well as in groups divided by stages of the disease. We demonstrate that patients in Stage I and II of the disease who experience disease recurrence have statistically significant higher expression of CD44+ in primary tumor specimen. They also have shorter DFS and OS. Coexpression of CD44/CD166 antibody also have strong negative impact on recurrence, disease free survival and overall survival in Stage I and II patients. There is no correlation between presence of colon cancer stem cells and recurrence nor presence of colon cancer stem cells had impact on disease free survival and overall survival. Presence of CD166 and &alpha;-Lgr5 expression did not show significant impact on recurrence nor disease free survival and overall survival as in group of all patients as well in group of patients divided by stages of the disease. High expression of CD44+ and coexpression of CD44/CD166+ colon cancer stem cell markers in primary tumor specimen correlates with higher chance for disease recurrence and also leads to shorter DFS and OS.</p>