Zhang, Zhiyi. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves ). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

It was previously demonstrated that miR-199a was down-regulated in testicular germ cell tumor (TGCT) partly caused by hypermethylation of its promoter. More detailed analyses showed that miR-199a-5p, one of its two derivatives, suppressed TGCT invasiveness and proliferation via directing targeting PODXL and MAFB. The biological role of the other derivative, miR-199a-3p in TGCT, remains largely uncharacterized. In this project we identified DNMT3A, the de novo methyltransferase, as a direct target of miR-199a-3p using a 3’-UTR reporter assay. In NT2 (NTera 2) and HT (Hs 1.Tes) cells, miR-199a-3p regulated the expression of endogenous DNMT3A (both DNMT3A1 and DNMT3A2 isoforms), especially DNMT3A2 isoform. In clinical samples, the expression of DNMT3A2 and miR-199a-3p were reciprocally regulated. However, DNMT3A did not regulate miR-199a expression. Further characterization of miR-199a-3p revealed that it negatively regulated DNA methylation partly through targeting DNMT3A. MiR-199a-3p could restore the expression of APC and MGMT via de-methylation in their promoters. Our studies demonstrated the dysregulation of miR-199a-3p in TGCT may provide novel mechanistic insights into TGCT carcinogenesis and suggested a potential therapeutic use of synthetic miR-199a-3p oligonucleotides as effective demethylation agent in the treatment of TGCT. However, since DNMT3A expression did not regulate miR-199a expression, the mechanism of promoter DNA hypermethylation of miR-199a in TGCT needs further investigation. / MiR-199a is encoded by two loci in the human genome, namely, miR-199a-1 on chromosome 19 and miR-199a-2 on chromosome 1. Another microRNA, miR-214, also locates on chromosome 1. Previous study revealed that it is co-transcribed with miR-199a-2, which is directed by miR-199a-2 promoter. However, the biological significance of the co-expression of miR-199a and miR-214 remains largely unknown. In this project, it was determined that miR-199a and miR-214 were concordantly expressed in TGCT. Silencing of DNMT1 increased the expression of miR-199a and miR-214, accompanied by de-methylation in the promoters of miR-199a-1/2. Overexpression of TP53 down-regulated the expression of DNMT1 and increased the expression of mature miR-199-3p/5p and miR-214. In addition, silencing of PSMD10 up-regulated the expression of TP53, while miR-214 over-expression resulted in PSMD10 down-regulation and TP53 up-regulation. Collectively, our findings highlighted a miR-199a/miR-214/PSMD10/TP53/DNMT1 self-regulatory network, which caused the down-regulation of miR-199a, miR-214 and TP53, as well as the up-regulation of DNMT1 and PSMD10 in TGCT. These observations partly explain the mechanism of promoter DNA hypermethylation in miR-199a in TGCT. They also suggest a potential therapeutic approach by targeting the miR-199a/miR-214/PSMD10/TP53/DNMT1 regulatory network in the treatment of TGCT. / 先前的研究證實miR-199a在睾丸生殖細胞腫瘤 (簡稱睾丸癌) 中是低表達的，部分歸因於其啟動子區域過度甲基化。對其功能研究發現miR-199a能抑制睾丸癌細胞的生長，侵襲和轉移，且miR-199a的抑癌屬性應歸功於它的兩個衍生物之一miR-199a-5p。然而，miR-199a的另一個衍生物miR-199a-3p在睾丸癌中的生物學功能仍然在很大程度上是未知的。此研究中，DNMT3A被鑒定為miR-199a-3p的直接靶定目標。在NT2和HT細胞中，miR-199a-3p能調控內源性DNMT3A(DNMT3A1和DNMT3A2)的表達水準，尤其是DNMT3A2。在臨床樣本中，DNMT3A2的表達水準與miR-199a-3p的表達水準呈負相關。但DNMT3A並不能調控miR-199a的表達水準。進一步研究顯示過表達miR-199a-3p能減少APC和MGMT啟動子區域甲基化而恢復其表達水準。研究證實異常表達的miR-199-3p可能在睾丸癌的癌變過程中發揮作用，並提出一個潛在的治療方案，即使用miR-199a -3p作為有效的去甲基化藥劑治療睾丸癌。然而睾丸癌中導致miR-199a啟動子區域過度甲基化的機制有待進一步研究。 / 在人類基因組中，miR-199a-1(位於19號染色體)和miR-199a-2(位於1號染色體)都編碼miR-199a。同時miR -214也位於1號染色體，研究表明miR-214與miR-199a-2由miR-199a-2啟動子介導共同轉錄，但miR-199a和miR- 214共同表達的生物學意義仍未知。此研究中，miR-199a和miR-214在睾丸癌中的表達呈現一致性。沉默DNMT1後miR-199a和miR-214的表達水準顯著提高，並伴隨著miR-199a-1/2啟動子區域的DNA去甲基化。在NT2細胞中。過表達TP53能下調DNMT1的表達水準，同時上調miR-199-3p/5p和miR- 214的表達水準。此外，過表達miR -214能導致PSMD10表達水準的下調以及TP53表達水準的上調。綜上所述，我們提出一個miR-199a/miR-214/PSMD10/TP53/DNMT1自我調控網路，此調控通路能引起睾丸癌中miR-199a，miR-214和TP53表達水準的下調，以及DNMT1和PSMD10表達水準的上調，且部分解釋睾丸癌中miR-199a啟動子區域過度甲基化的機制，同時該調控網路可作為治療睾丸癌的一個潛在靶點。 / Chen, Bifeng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 103-127). / Abstracts also in Chinese. / Title from PDF title page (viewed on 20, December, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Objective: P300/CBP Associated Factor (PCAF) is a histone acetyltransferase, and has been reported to interact with nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and to stimulate cyclooxygenase-2 (COX-2) transcriptional activation. The aim of this study was to determine the role of PCAF in chronic pain modulation. / Method: In an in vitro experiment, PCAF small-interfering RNA (siRNA) was used to knock down PCAF. Interleukin-1 β (IL1β) was applied as COX-2 inducer in SK-N-SH neuroblastoma cells. Luciferase assay and chromatin immunoprecipitation (ChIP) were performed regarding COX-2 promoter region. / In an in vivo experiment, PCAF was examined for its distribution in dorsal horn of Spraque-Dawley rats. COX-2 level in the spinal cord was determined after inhibition of PCAF in rats with Complete Freund's Adjuvant (CFA)-induced pain. ChIP was also performed. / Finally, we tested whether genetic variations in the PCAF gene affected the risk of chronic pain in a gene association study of 267 surgical patients. The associations of pain with genotypes (58 single nucleotide polymorphisms, SNPs)/haplotypes were analyzed by χ² and Fisher exact tests. / Results: Knock-down of PCAF reduced COX-2 level and NF-κB activity. PCAF and acetylated histone 3 lysine 14 (H3K14) were enriched at COX-2 promoter when IL1β was applied. / PCAF was expressed in neurons at superficial layers of rat dorsal horn. In the in vivo experiment, COX-2 was reduced with the inhibition of PCAF in CFA rats. PCAF was enhanced at COX-2 promoter when CFA was injected. Anacardic acid and PCAF siRNA significantly alleviated thermal nociception and mechanical allodynia. / In the gene association study, 6 SNPs and 5 haplotypes were significantly associated with higher risk of severe chronic postsurgical pain. Multivariable analysis showed that patients with a SNP rs6763504 had a higher risk of developing severe chronic postsurgical pain (p = 0.001). / Conclusion: PCAF regulated COX-2 transcription and reduction or inhibition in PCAF resulted in a decrease in COX-2 and less chronic inflammatory pain. Genetic variations in the PCAF gene increased risk of severe chronic post-surgical pain in patients. / 實驗目的：P300/CBP相關蛋白（PCAF）是一種組蛋白乙酰化轉移酶。這種蛋白已被報道可以和核因子活化B細胞κ輕鏈增強子(NF-κB)相互作用，以及增進環氧合酶-2（COX-2）的轉錄激活。本實驗的目的在於研究PCAF在疼痛調節中的作用。 / 實驗方法：在細胞實驗中，我們使用了小干擾RNA（siRNA）來降低PCAF的含量。同時我們使用了白細胞介素-1β（IL1β）來作為SK-N-SH神經母細胞瘤細胞中COX-2的誘導劑。我們使用了熒光素酶試劑和染色質免疫沉澱來研究COX-2啟動子區域。 / 在體內實驗中，我們檢測了PCAF在大鼠脊椎背角部位的分佈。在弗氏完全佐劑（CFA）致痛的大鼠模型中，我們在PCAF抑制的情況下檢測脊髓中COX-2的水平。我們還進行了染色質免疫沉澱。 / 最後，在招募了267位手術患者的基因關聯試驗中，我們對PCAF基因中的基因變異對慢性疼痛風險的影響進行了分析。我們運用卡方檢驗和費雪精確性檢驗對疼痛與基因型（58個單核苷酸多態性）和單倍型的關係進行分析。 / 實驗結果：減少的PCAF降低了COX-2的水平以及NF-κB的活性。當添加了IL1β時PCAF和乙酰化第三組蛋白14號賴胺酸（H3K14）在COX-2啟動子處富集。 / PCAF在大鼠脊椎背角部位的淺表層（第一層和第二層）的神經細胞里表達。在動物實驗中，注射了CFA的大鼠顯示COX-2會隨著PCAF的抑制而下降。大鼠注射了CFA后PCAF在COX-2啟動子處有所增加。漆樹酸和PCAF siRNA顯著地減輕了熱痛和機械痛提高了機械痛閾值。 / 在該基因關聯試驗中，我們鑒定出六個單核苷酸多態性和五種單倍型與較高風險的嚴重術後慢性痛有顯著的相關性。多元回歸分析表明在PCAF基因上具有rs6763504遺傳變異的病人在術後發展嚴重慢性痛的幾率會較高(p = 0.001)。 / 結論：PCAF調節COX-2的轉錄，而且PCAF的減少或者抑制導致了COX-2的降低同時慢性炎症痛的減少。PCAF基因上的遺傳變異提高了術後病人嚴重慢性痛的風險。 / Meng, Zhaoyu. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 117-134). / Abstracts also in Chinese. / Title from PDF title page (viewed on 30, December, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Amplification of chr.1 q21-22 is also an aberration frequently detected in HCC. Copy number gains of the GEF-H1 gene ranked the most frequent event from array-CGH. GEF-H1 up-regulation was significant correlated in patients with advanced HCC staging (P = 0.048), presence of micro-vascular invasion (P = 0.049) and shorter overall and disease free survival of patients (P < 0.03). Similar to BOP1, functional examinations of GEF-H1 suggested profound inhibitory effects on cell motility ( P < 0.035) and invasiveness (P < 0.003) in cell lines studied. Upon GEF-H1 depletion, re-expression of epithelial markers (E-cadherin, cytokeratin 18, alpha-catenin and gamma-catenin) and down-regulations of mesenchymal markers (N-cadherin, fibronectin and vimentin) were also readily observed. In addition, reduced active form of GTP-RhoA together with its downstream effectors including cleaved ROCK 1 and phosphorylated MLC2 were also found in GEF-H1 depleted cells. / Array-CGH also defined candidate proto-oncogenes within 2 causal amplified regions in HCC, chr.8q24 and chr.1q21-q22. In resolving affected genes at chr.8q24, distinctive gains of BOP1 was further established in primary HCC tumors, where frequent BOP1 up-regulations in tumors compared to adjacent non-tumoral liver (P < 0.0001) was identified. Increased BOP1 expression correlated with advanced HCC staging (P = 0.004), micro-vascular invasion (P = 0.006) and shorter overall and disease free survival of patients (P < 0.02). siRNA-mediated suppression of BOP1 in HCC cell lines showed significant inhibition on cell invasion (P < 0.003) and migration (P < 0.05), whereas overexpression of BOP1 in immortalized hepatocyte cell line, L02, showed increase cellular invasiveness and cell migratory rate (P < 0.0001). Evident regression of the Epithelial-to-Mesenchymal Transition (EMT) phenotype was readily identified in BOP1 knockdown cells, where re-expressions of epithelial markers (E-cadherin, cytokeratin 18 and gamma-catenin) and down-regulation of mesenchymal markers (fibronectin and vimentin) were found. It was found that BOP1 likely stimulates actin stress fibers assembly through RhoA activation. / Hepatocellular carcinoma (HCC) is a highly malignant tumor that is associated with a high incidence of cancer morbidity and mortality. Elucidation of genomic aberrations of HCC holds much importance in understanding the molecular basis that underlies the disease causation and progression. Extensive research on HCC has by now revealed a number of key genomic aberrations but, for most of these loci, the underlying cancer-related gene(s) remains unknown. / In this thesis, array-based comparative genomic hybridization (array-CGH) was deployed to define target genes within HCC-associated chromosomal regions. The first part of my study focused on mapping the homozygous deletions (HDs) in HCC. Though infrequent, HD screening has been widely utilized to define tumor suppressor genes (TSGs) in cancers. A panel of HCC cell lines was systematically examined for the presence of HDs. Array-CGH identified 6 HD regions, amongst which CRYL1 (located on chr.13q12.11) displayed most common down-regulations in primary HCC tumors. Significant associations could also be drawn between repressed CRYL1 and advanced tumor staging, increased tumor size and shorter disease-free patient survival (P ≤ 0.037). Moreover, HD on CRYL1 could be detected in 36% of HCC cases with CRYL1 down-regulations. Examination of other inactivating mechanisms suggested histone deacetylation and promoter hypermethylation to be likely inactivating events as well. Re-expression of CRYL1 in SK-HEP1 cell line induced profound inhibition on cellular proliferation and cell growth (P ≤ 0.002). By Annexin V staining, CRYL1 restoration readily increased pro-apoptotic cells with an induction of P ARP cleavage. Flow cytometry further revealed CRYL1 could prolong the G2-M phase, possibly through interrupting the Cdc2/cyclin B path. / The similarities in functional behaviours of BOP1 and GEF-H1 might have implications in the fundamental biology of HCC tumorigenesis. It is known that HCC is a highly aggressive tumor often associated with intra- and extra-hepatic metastasis. The finding of 2 causal changes to be closely associated with cell migration and invasiveness may have implications in the metastatic potentials of HCC cells being predisposed earlier on from genomic events. / Cheng, Kit Chong Ibis. / Adviser: Nathalie Wong. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 177-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Ng, Chor Fung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 156-169). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Chan, Ho Ching. / Thesis M.Phil. Chinese University of Hong Kong 2016. / Includes bibliographical references (leaves 159-166). / Abstracts also in Chinese. / Title from PDF title page (viewed on 15, September, 2016).

Lam, Man Ting. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 128-138). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Li, Martin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 187-208). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Au Yeung Chi Lam. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 204-221). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Wang, Shiyan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 123-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.