A 24-hour fermentation of the optimized synbiotic composed of B. longum and EPR was performed to give a cell-free fermentation broth (S24). S24 was co-cultured with two colon cancer cell lines (Caco-2 and SW620) and normal colon cells (FHC). S24 significantly inhibited cell proliferation for both colon cancer cells but promoted FHC cell growth by 10-25% as shown by MTT and BrdU arrays. Primary DNA damage analysis by alkaline comet assay showed S24 caused DNA damage to a comparable extent as the positive control of 10 mM H2O2 (treated for 1 hour) for both cancer cells. Dynamic analysis on DNA damage-associated DNA repair showed the two colon cancer cells had different response pattern to S24. Flow cytometric analysis showed that both Caco-2 and SW620 when treated with S24 (IC 50=3.66 mM of acetate) were arrested initially at G2/M and subsequently at S phase accompanied with large sub-G1 peaks. Dual staining with PI/AnnexinV further proved the appearance of apoptosis. Live cell imaging analysis on Caco-2 cells treated with S24 showed the following events: mitochondria were rapidly destroyed within the first two-hour treatment, the cells bubbled and the nucleus condensed after the mitochondrial had shrunken, followed by apoptosis. / Despite active research on synbiotic on anti-carcinogenesis of colon cancer by synbiotics, the underlying mechanism still remains unclear. This study investigated a novel synbiotic composed of non-digestible carbohydrates (NDCs) extracted from mushroom sclerotia as prebiotics and Bifidobacteria as probiotics. Preliminary results on incubation of two probiotics ( Bifidobacterium longum and Lactobacillus brevis) and one pathogenic bacterium (Clostridium celatum) separately with 3 NDCs extracted from mushroom sclerotia [Poria cocos (PC), Polyporus rhinocerus (PR) and Pleurotus tuber-regium (PT)] indicated that the growth of B. longum and L. brevis was stimulated more preferentially than C. celatum after 72-hour fermentation. The short-chain fatty acid (SCFA) profile was dominated by acetate (> 98% of total SCFAs) with very little butyrate (< 2.0% of total SCFAs) and the organic matter disappearance (OMD) during fermentation was consistent with the bacterial growth. Among the synbiotic combinations, NDC from PR and B. longum gave the largest amount of acetate (2.47+/-0.232 mmol/g of organic matter disappearance). / Results obtained from human pathway finder RT2 Profiler(TM) PCR Array indicated that S24 could modulate the proliferation of colon cancer cells mainly by various pathways such as cell cycle and DNA damage repair, apoptosis and cell senescence, etc. In SW620 cells, PCR Array of Human Cell Cycle further revealed that the modulated genes mainly belonged to the gene cluster of S phase and DNA replication as well as G2 and G2/M transition. While for Caco-2 cells, the cell-cycle modulated genes mainly belonged to the cluster of G2 and G2/M transition. Immuno-blotting on the pivotal upstream regulators showed that phosphorylation of ATM at Serine 1981 was significantly increased in both cancer cells. Site-specific phosphorylation of pRB was decreased and phosphorylation of Chk1 was increased in both cancer cells while Chk2 were increased in SW620 cells. Cdc25A was phosphorylated at serine17 in both cancer cells. It can be proposed that the blockage of DNA synthesis or DNA damage was due to the down-regulation of some pivotal DNA replication related proteins such as RPA3, PCNA and MCMs, detected by ATM-Chk1/Chk2-Cdc25A pathway. This would cause the prolonged staying of cells at the G1/S checkpoint which further moved on to S phase arrest for SW620 cells. Moreover the sharply up-regulated p21, an important inhibitor of Cdk2 would further hinder the cells passing the G1/S checkpoint in SW620 cells. / The tumor suppressor p53 was detected phosphorylated at various sites in SW620 but not in Caco-2 cells. In SW620 cells, G2/M arrest was caused by the inhibition of CDK1/CDC2 due to increased expression of GADD45A and p21 and phosphorylation of Cdc25A, while for Caco-2, the G2/M arrest was caused by degradation of Cdc25A due to the absence of p53-activated GADD45A and p21 expression as shown in the pathway finder results. Some apoptosis-related proteins of Bax, Apaf-1 and PARP were modulated as shown by immuno-blotting in both colon cancer cells. (Abstract shortened by UMI.) / Gao, Shane. / Adviser: Peter Chi-Keung Cheung. / Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 55-94). / 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.

Cheung, Wing Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 100-112). / Abstracts in English and Chinese. / Acknowledgments / Abbreviations / Abstract 一 English --- p.i / - Chinese --- p.iii / Chapter Chapter 1 --- General Introduction / Chapter 1.1. --- Colon Cancer / Chapter 1.1.1. --- Colon cancer statistic in Hong Kong --- p.1 / Chapter 1.1.2. --- Development of Colon cancer --- p.1 / Chapter 1.1.3. --- Treatment --- p.2 / Chapter 1.2. --- Chemistry of ascorbates / Chapter 1.2.1. --- Sodium-L-ascorbate --- p.3 / Chapter 1.2.2. --- "Sodium 5,6-benazylidene-L-ascorbate" --- p.4 / Chapter 1.3. --- "Reactive oxygen species and reactive nitrogen species, and their biological consequences" --- p.5 / Chapter 1.4. --- Cell cycle --- p.7 / Chapter 1.5. --- Autophagy --- p.8 / Chapter 1.6. --- Human colon cancer HT29 cells for anti-tumor study --- p.9 / Chapter 1.7 --- Aim of study --- p.10 / Chapter Chapter 2 --- Comparative studies of cytotoxicity of SAA and SBA in short term treatment / Chapter 2.1. --- Introduction --- p.11 / Chapter 2.2. --- Materials and Methods --- p.14 / Chapter 2.3. --- Results --- p.17 / Chapter 2.4. --- Discussion --- p.26 / Chapter Chapter 3 --- Comparative studies of SAA and SBA in oxidative stress induction and their corresponding ROS inhibitors / Chapter 3.1. --- Introduction --- p.28 / Chapter 3.2. --- Materials and Methods --- p.31 / Chapter 3.3. --- Results --- p.35 / Chapter 3.4. --- Discussion --- p.42 / Chapter Chapter 4 --- "Effects of SAA and SBA treatments on cell cycle regulatory proteins and the induction of transient cell cycle arrests in Gl, S and G2 phases Cell Cycle" / Chapter 4.1. --- Introduction --- p.45 / Chapter 4.2. --- Materials and Methods --- p.49 / Chapter 4.3. --- Results --- p.53 / Chapter 4.4. --- Discussion --- p.69 / Chapter Chapter 5 --- Autophagy induction during SBA treatment and autophagy inhibition during SAA treatment / Chapter 5.1. --- Introduction --- p.72 / Chapter 5.2. --- Materials and Methods --- p.74 / Chapter 5.3. --- Results --- p.77 / Chapter 5.4. --- Discussion --- p.91 / Chapter Chapter 6 --- General Discussion --- p.93 / References --- p.100

Lectins (hemagglutinins) are a type of proteins that could recognize different sugar structures and specifically initiate reversible binding with them. Though they have been universally found in a variety of organisms, they are exceptionally abundant in legumes. From the initial finding of agglutinating red blood cells to the discovery of recognizing carbohydrates on cell membranes, multiple functions of lectins have been gradually unveiled by numerous researchers across a century. Based on its carbohydrate-binding property, lectins have found great value in the study of glycomics. Many lectin-based biological tools, like lectin affinity chromatography, lectin blotting, lectin histochemistry, lectin microarray and lectin-based biosensor have been developed and applied to the study of glycoproteins. Besides, lectins are also reported to be potential agents for anti-insect, anti-fungi, anti-HIV, anti-bacterial and anti-tumor applications. / The present study focuses on the isolation of a new hemagglutinin from an edible legume, exploration of its anti-colorectal cancer effect and mechanisms, its cytokine inducing function and anti-HIV activities. The protein was purified by liquid chromatography techniques which entailed affinity chromatography on Affi-Gel Blue Gel, ion exchange chromatography on Mono Q and gel filtration on Superdex 75 with an FPLC system. The hemagglutinating activity of this hemagglutinin was demonstrated to be ion-dependent and stable over a wide range of temperatures (20-60℃) and pH (2-11) values. Like most of the lectins or hemagglutinins, this novel hemagglutinin could also attenuate the activity of HIV-1 reverse transcriptase. / This hemagglutinin could potently suppress the proliferation of colorectal carcinoma HCT116 cells and colorectal adenocarcinoma HT29 cells. It induced cell cycle arrest in G0/G1 phase, downregulated the expression of Cyclin D1 and upregulated P21expression. The protein initially bound on the cell membranes most probably through glycoproteins and subsequently entered the cytoplasm, which was achieved as early as 3h post treatment. The hemagglutinin was found to be preferentially localized in Golgi apparatus and initiated aggregation of the Golgi apparatus, which may possibly attenuate its protein processing capacity by reducing total superficial area or even partially blocking the transportation of proteins from the endoplasmic reticulum (ER). The impaired protein reception ability of Golgi apparatus may lead to the protein accumulation in the ER and induce cell apoptosis. Accordingly, two ER stress sensors (IRE1α and ATF6) and one late product of ER stress (CHOP) were found to up-regulated. Apoptosis-inducing effect of this hemagglutinin on HT29 and HCT116 cells were further confirmed using methods based on different principles. Cells treated with the hemagglutinin were observed to undergo obvious chromatin condensation, mitochondrial membrane depolarization and phosphatidylserine exposure. An apoptosis initiator (Apaf-1) and one important indicator (cleaved PARP) of cell apoptosis were accordingly detected. Besides, intraperitoneal administration of this hemagglutinin to colorectal tumor bearing nude mice could slow down the growth of tumors. / At last, this hemagglutinin exerted an immunomodulatory function on splenocytes by stimulating the mRNA expression level of interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), interferon- gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α). Secretion of IL-1β and IL-2 from splenocytes also increased with the concentration of this hemagglutinin. / In a short conclusion, we have isolated a new hemagglutinin with anti-HIV RT, anti-colorectal cancer and immunomodulatory activities. / 凝集素（血凝素）是一类能够识别不同糖结构并能和它们发生可逆性结合的蛋白。虽然他们在许多生物体内均有发现，但这类蛋白在豆科植物中的含量尤其丰富。经过一个多世纪来众多研究者的努力，从最初认识到其具有红血细胞凝集功能到糖类识别作用，凝集素的诸多功能已被逐步挖掘。基于其独特的糖结构识别特性，凝集素在糖组学的研究中具有重大意义。许多基于凝集素的生物方法，如凝集素亲和层析法，凝集素印迹法，凝集素组织化学，凝集素生物芯片以及基于凝集素的生物传感器已被研究出来, 并用于研究糖蛋白。除此之外，研究表明，凝集素还具有抗虫，抗真菌，抗HIV，抗细菌和抗癌等活性。 / 该凝集素可以极大抑制结肠直肠癌HCT116细胞和结直肠腺癌HT29细胞增殖，引发细胞周期停滞，分别下调和上调Cyclin D1和P21的表达。该蛋白极有可能首先通过和细胞表面的糖蛋白结合而附在细胞膜上，然后进入细胞内。该过程可在往细胞培养液内加入该蛋白后的3小时内完成。该凝集素优先与细胞内的高尔基体结合，随后引发高尔基体聚集。该聚集作用可能会通过减少高尔基体总表面积甚至阻塞内质网和高尔基体间的蛋白运输，进而减弱高尔基体处理蛋白质的能力。当高尔基体接受蛋白的能力降低时，蛋白可能会堆积在内质网上并进一步引发细胞程序性死亡。相应地，两个内质网应激感受蛋白IRE1α和 ATF6以及内质网应激后期产物CHOP均被发现上调。该凝集素对HT29细胞和HCT116细胞的凋亡诱导作用采用不同的方法进行了进一步的确认，这些方法都是基于不同检测原理进行的。结果表明，该凝集素可导致细胞产生明显的染色质凝缩，线粒体膜电位去极化和磷脂酰丝氨酸外翻。与此相应地，凋亡启动蛋白Apaf-1和凋亡后期蛋白(被剪切的PARP)可在处理后的细胞中检测到。通过腹腔注射的方法给接种大肠癌细胞的裸鼠给药可降低肿瘤的生长速度。 / 本研究的工作包括：从一种可食用豆类中提取一种新的凝集素；检测其抗大肠癌的作用和机制；研究其细胞素诱导作用以及抗HIV活性。该蛋白采用液相色谱法分离提纯，其中包括亲和层析柱Affi-Gel Blue Gel, 离子交换层析柱Mono Q 和凝胶层析柱Superdex 75，后两种层析法在FPLC系统上操作。该蛋白的红血细胞凝集作用具有金属阳离子依赖性，并在20-60℃和pH2-11范围内保持活性稳定。像许多其它的凝集素一样，该蛋白也可以削弱HIV逆转录酶活性。 / 最后，该蛋白还具有免疫调节作用，它可促进白细胞介素-2，白细胞介素-6，白细胞介素-1β，干扰素-γ和肿瘤坏死因数-α在mRNA水平上的表达并刺激白细胞介素-2和细胞介素-1β的分泌。 / 综上所诉，本研究分离提纯了一种新凝集素，它具有抗HIV，抗大肠癌和免疫调节作用。 / Dan, Xiuli. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 153-170). / Abstracts also in Chinese. / Title from PDF title page (viewed on 05, October, 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.

丹参是一种著名的传统中药，富含丹酚酸和丹参酮。其中，丹参酮的潜在抗肿瘤作用近年来引起众多关注。本研究评价了主要的丹参酮及其衍生物对结肠癌细胞的细胞毒性。结果显示DHTS具有最强的抗结肠癌活性和显著的肿瘤特异性细胞毒性，其细胞毒性主要由于凋亡诱导而不是引起坏死。初步的构效关系分析提示丹参酮母环结构中的A环和B环增加的离域性有助于提高其对结肠癌细胞的细胞毒性，而非二维结构及较小的D环也是进行结构改造的可能方向。 / 基于以上发现，本研究进一步探讨了DHTS的体内外抗肿瘤活性及内在机制。本研究发现DHTS的促凋亡活性并不依赖于p53的表达，而依赖于caspase活性及线粒体介导的细胞质中氧自由基 ROS及钙离子的聚集。DHTS可引起浓度及时间依赖caspase-9/-3/-7的活化而并未显著引起caspase-8的活化，这一现象发生于同样以浓度及时间依赖方式进行的线粒体中cytochrome c及AIF转位之后。在DHTS诱导的结肠癌细胞凋亡中，cytochrome c及caspase介导的凋亡通路及AIF介导的凋亡通路均被激活并显示出两条通路之间的交叉调控。 / 此外，线粒体在DHTS的促凋亡活性中的作用在本研究中被深入探讨。本研究发现线粒体可能是DHTS的一个直接靶点, 而氧化磷酸化复合体III则更可能是其作用位点。DHTS可以引起迅速而明显的线粒体功能障碍，随之引起细胞质中大量的氧自由基及钙离子聚集，诱导凋亡的产生。 / 与体外结果一致，本研究证实了DHTS对免疫缺陷小鼠中的结肠癌移植廇也具有明显的抗肿瘤作用。与溶媒对照组比较，DHTS治疗组中移植廇的增长显著被减缓，在治疗终点时的廇体积与重量也显著被降低。TUNEL检测确认DHTS诱导移植廇中癌细胞的显著凋亡。免疫荧光检测也发现DHTS诱导caspase-3及caspase-7在移植廇中癌细胞的明显活化。 / 综上所述，本研究提供了丹参酮抗结肠癌活性的一些初步构效关系的信息，为提高丹参酮抗结肠癌活性的结构改造提供一定的参考。更重要的是，本研究证明了DHTS的体内外抗结肠癌活性并探讨了其作用机制及可能靶点，为DHTS作为新的应用于抗结肠癌药物或辅助治疗用药提供了临床前研究证据。 / Salvia miltiorrhiza Bunge, also known as Danshen, rich in phenolic acid and tanshinones, has been widely used to treat various kinds of diseases including heart diseases and hepatitis in China with minimal side effects. Among the tanshinones, tanshinone I, tanshinone IIA, cryptotanshinone and dihydrotanshinone I are the major bioactive constituents in this herb. In this study, the anti-colon cancer potential of five tanshinones and six derivatives of tanshinone IIA were evaluated in several colon cancer cell lines. It was found that apoptosis but not necrosis contributed significantly to the cytotoxicity of the tanshinones. Dihydrotanshinone I (DHTS) was confirmed to be the most potent and selective anti-cancer compound among the tanshinones tested in this study. Preliminary SAR (structure activity relationship) of tanshinones reveals that the increase of delocalizability of A and B rings in the chemical structure of the tanshinones enhances their cytotoxicity on cancer cells, while compounds with a non-planar and small sized D ring region are better choices for anti-cancer effect. / The underlying mechanisms of the anti-colon cancer activity of DHTS were further studied. It was found that apoptosis induced by DHTS was p53 independent but caspase dependent, which was closely related to intracellular accumulation of ROS (reactive oxidant stress) and calcium mediated by mitochondria. A concentration- and time-dependent activation of caspase-9,-3,-7 but not caspase-8 by DHTS in HCT116 cells was detected after the translocation of cytochrome c and AIF (apoptosis inducing factor) from mitochondria. In this process, the crosstalk between the caspase-dependent and caspase-independent pathways was firstly shown in the apoptotic mechanism of DHTS. To this end, the release of cytochrome c happened first and the translocation of apoptosis inducing factor (AIF) was prevented by a pan caspase inhibitor. In the meantime, the release of cytochrome c and activation of caspase-9 and PARP (poly-ADP-ribose polymerase) cleavage were decreased after AIF knockdown. Especially, mitochondrion was suggested to be the direct target of DHTS and OXPHOS complex III but not OXPHOS complex I was probably the acting site of DHTS. / In accordance with the results obtained in vitro, the potential anti-colon cancer activity of DHTS was also observed in nude mice with xenograft tumors and the compound did not produce any observable systemic toxicity. DHTS efficiently delayed tumor growth by decreasing the tumor size and weight through the induction of apoptosis in cancer cells but not by inhibition of cell proliferation. In the same tissues, a distinct activation of caspase-3 and caspase-7 in tumor cells was also detected by immunofluorescence assay. / Collectively, the present study provides preliminary information about the SAR of the anti-colon cancer activity for tanshinones. It also confirms that DHTS is a promising compound for anti-cancer action both in vitro and in vivo. In addition, this study gives us a better understanding regarding the mechanisms of how DHTS induces apoptosis in cancer cells. All these findings could provide solid pre-clinical evidence to propel the development and application of DHTS and perhaps its derivatives as novel therapeutic or adjuvant agents for the treatment of colon cancer. / 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. / Wang, Lin. / Thesis (Ph.D.) Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 122-132). / Abstracts also in Chinese. / Wang, Lin.