Through the two binary gene expression systems for spatiotemporal gene expression in Drosophila

[[abstract]]在以果蠅為模式動物的研究中，GAL4/UAS 雙元基因表現系統(binary expression system)是廣泛被運用在限制目標基因於特定空間表現的技術，操作上若與GAL80ts 結合使用(即TARGET system)，經由溫度的變化，則更能將基因限制表達在特定的時間與空間。遺憾的，在一些以果蠅為模式動物的研究證據中顯示，溫度的變化會對某些實驗結果造成影響。因此，在本研究中，我們建立一個新的基因調控策略，利用已被廣泛應用於果蠅的GAL4/UAS 系統，表現一個必須經由RU486(或17β-estradiol)活化之轉錄因子(transactivator)- LexPR(或XVE)，在特定時間下經由藥物活化後，即可藉此為橋樑連結至另一雙元基因表現系統，轉錄LexAop 下游之目標基因。藉此方法，將可以避免因使用GAL80ts 調控基因表現時，因溫度改變對研究結果所產生的不良影響。本論文透過定性及定量分析，證明此方法的確可運用於果蠅模式動物，此方法的建立因保留GAL4 driver之豐富性，並減少因溫度改變而造成實驗分析的影響，達到限制基因於特定空間與時間之表現，可以預見對後續以果蠅為模式動物之基因研究有著重要的影響。[[abstract]]The GAL4/UAS gene expression system is applied frequently in Drosophila. Combining the conventional GAL4/UAS system and temperature-sensitive Gal80(GAL80ts) is able to regulate gene expression through temperature alteration. However, the target gene expression can never be completely restricted neither with temperature changing nor insertion at low basal activity loci. In this study, I generate a UAS-LexA-progesterone receptor chimera (known as LexPR) which under control by GAL4 and transactivate another binary LexA-LexAop gene-expression system when hormones mifepristone (RU486) is added. This new technique provides guidelines for acutely control gene expression through drug treatment, rather than altering temperature. Beside, the abundant GAL4 library can be applied to the new system. In brief, I provide a new strategy to acutely control and regulate the gene expression without affecting their physiological homeostasis in Drosophila.[[note]]碩

Five years of progress, 1907-1912: a report of the work of the Young Men's Christian Associations of China and Korea, 1912; with a review covering the period 1907-1912

In volume lettered: China and the Chinese. Pamphlets. Volume 29

Autophagic Mechanism in Anti-Cancer Immunity: Its Pros and Cons for Cancer Therapy

Autophagy, a self-eating machinery, has been reported as an adaptive response to maintain metabolic homeostasis when cancer cells encounter stress. It has been appreciated that autophagy acts as a double-edge sword to decide the fate of cancer cells upon stress factors, molecular subtypes, and microenvironmental conditions. Currently, the majority of evidence support that autophagy in cancer cells is a vital mechanism bringing on resistance to current and prospective treatments, yet whether autophagy affects the anticancer immune response remains unclear and controversial. Accumulated studies have demonstrated that triggering autophagy is able to facilitate anticancer immunity due to an increase in immunogenicity, whereas other studies suggested that autophagy is likely to disarm anticancer immunity mediated by cytotoxic T cells and nature killer (NK) cells. Hence, this contradiction needs to be elucidated. In this review, we discuss the role of autophagy in cancer cells per se and in cancer microenvironment as well as its dual regulatory roles in immune surveillance through modulating presentation of tumor antigens, development of immune cells, and expression of immune checkpoints. We further focus on emerging roles of autophagy induced by current treatments and its impact on anticancer immune response, and illustrate the pros and cons of utilizing autophagy in cancer immunotherapy based on preclinical references

Use of a Disposable Water Filter for Prevention of False-Positive Results due to Nontuberculosis Mycobacteria in a Clinical Laboratory Performing Routine Acid-Fast Staining for Tuberculosis▿

A point-of-use 0.2-μm filter was evaluated for elimination of nontuberculosis mycobacteria in laboratory water to reduce false-positive acid-fast bacillus staining results. Use of the point-of-use filter can significantly reduce the false-positive rate to 1.2% compared to samples treated with tap water (10.7%) and deionized water (8.7%)

Structural basis for the hydrolytic activity of the transpeptidase-like protein DpaA to detach Braun’s lipoprotein from peptidoglycan

ABSTRACT The peptidoglycan layer is a defining characteristic of bacterial cells, providing them with structural support and osmotic protection. In Escherichia coli, this layer is linked to the outer membrane via the abundant membrane-anchored protein Lpp, known as Braun’s lipoprotein, with LD-transpeptidases LdtA, LdtB, and LdtC catalyzing the attachment. However, one distinctive member of the YkuD-type transpeptidase family, LdtF (recently renamed DpaA), carries out the opposite reaction of detaching Lpp from the peptidoglycan layer. In this study, we report the crystal structure of DpaA, which reveals the enzyme’s ability to cleave, rather than form, the Lpp-peptidoglycan linkage. Assays with purified peptidoglycan-Lpp as the substrate and chemically synthesized compounds suggest that DpaA’s shallow L-shaped active site can only accommodate and cleave the peptidoglycan-Lpp cross-link with a constrained conformation. This study provides insights into how homologous Ldt enzymes can perform opposing chemical reactions. IMPORTANCE Cross-linking reaction of Braun's lipoprotein (Lpp) to peptidoglycan (PG) is catalyzed by some members of the YkuD family of transpeptidases. However, the exact opposite reaction of cleaving the Lpp-PG cross-link is performed by DpaA, which is also a YkuD-like protein. In this work, we determined the crystal structure of DpaA to provide the molecular rationale for the ability of the transpeptidase-like protein to cleave, rather than form, the Lpp-PG linkage. Our findings also revealed the structural features that distinguish the different functional types of the YkuD family enzymes from one another

Caffeic Acid Phenethyl Ester Inhibits Oral Cancer Cell Metastasis by Regulating Matrix Metalloproteinase-2 and the Mitogen-Activated Protein Kinase Pathway

Caffeic acid phenethyl ester (CAPE), an active component extracted from honeybee hives, exhibits anti-inflammatory and anticancer activities. However, the molecular mechanism by which CAPE affects oral cancer cell metastasis has yet to be elucidated. In this study, we investigated the potential mechanisms underlying the effects of CAPE on the invasive ability of SCC-9 oral cancer cells. Results showed that CAPE attenuated SCC-9 cell migration and invasion at noncytotoxic concentrations (0 μM to 40 μM). Western blot and gelatin zymography analysis findings further indicated that CAPE downregulated matrix metalloproteinase-2 (MMP-2) protein expression and inhibited its enzymatic activity. CAPE exerted its inhibitory effects on MMP-2 expression and activity by upregulating tissue inhibitor of metalloproteinase-2 (TIMP-2) and potently decreased migration by reducing focal adhesion kinase (FAK) phosphorylation and the activation of its downstream signaling molecules p38/MAPK and JNK. These data indicate that CAPE could potentially be used as a chemoagent to prevent oral cancer metastasis

Blockade of Inhibitors of Apoptosis Proteins in Combination with Conventional Chemotherapy Leads to Synergistic Antitumor Activity in Medulloblastoma and Cancer Stem-Like Cells

<div><p>Background</p><p>Medulloblastoma (MB) is the most common pediatric primary malignant brain tumor. Approximately one-third of MB patients succumb to treatment failure and some survivors suffer detrimental side effects. Hence, the purpose of this study is to explore new therapeutic regimens to overcome chemotherapeutic agent resistance or reduce chemotherapy-induced toxicity.</p><p>Methods</p><p>We detected the expression of inhibitors of apoptosis proteins (IAPs) in MB and CD133+ MB cell lines and MB tissues using immunoblotting and immunohistochemical staining. The antitumor effects of inhibitors against IAPs on MB or CD133+ MB cells were evaluated by MTT assay, Annexin V/PI analysis, and caspase-3/7 activity. Autophagy was assessed by the conversion of light chain (LC) 3-I to LC3-II and Cyto-ID autophagy detection kit.</p><p>Results</p><p>MB cells showed higher expression of IAPs compared to normal astrocytes and normal brain tissues. Conventional chemotherapeutic agents combined with small-molecule IAP inhibitors (LCL161 or LBW242) showed a synergistic effect in MB cells. Combined treatments triggered apoptosis in MB cells through activation of caspase-3/7 and autophagic flux simultaneously. In addition, we found that CD133+ MB cells with features of cancer stem cells displayed higher levels of X-linked inhibitor of apoptosis (XIAP) and cellular inhibitor of apoptosis 1/2 (cIAP1/2), and were hypersensitive to treatment with IAP inhibitors.</p><p>Conclusions</p><p>These results shed light on the biological effects of combination therapy on MB cells and illustrate that IAP inhibitors are more effective for CD133+ stem-like MB cells.</p></div

Cathepsin B Expression and the Correlation with Clinical Aspects of Oral Squamous Cell Carcinoma - Fig 2

<p>Kaplan-Meier survival curve showing the relation between cytoplasmic CTSB expression in primary tumors and survival in 280 oral squamous cell carcinoma (OSCC) patients (A) and 109 buccal mucosa squamous cell carcinoma patients (B). (C) The CTSB expression was not correlated with progression free survival in OSCC patients (p = 0.097). (D) The progression free survival of buccal mucosa squamous cell carcinoma patients with positive CTSB staining was significantly lower than that of patients with negative CTSB staining (p = 0.011). (E) From TCGA (The Cancer Genome Atlas) database (<a href="https://tcga-data.nci.nih.gov/tcga/" target="_blank">https://tcga-data.nci.nih.gov/tcga/</a>), the Kaplan-Meier curve showed that higher expression of CTSD had a significantly poor survival in 107 oral cancer patients (p = 0.048). (F) The CTSL and (G) CTSS mRNA expression were not correlated with overall survival in oral cancer patients.</p

Cathepsin B knockdown in OC2 and CAL27 cells reduce cell migration.

<p>Western blot analysis showing the cathepsin B Knockdown efficiency in (A) OC2 cell and (B) CAL27 oral cancer cell lines. Detection of cell migration ability by transfected with control siRNA or CTSB siRNA in (C) OC2 cell and (D) CAL27 cell. Results shown that cathepsin B siRNA significantly reduced the migration of OC2 and CAL27 cells. *p<0.05.</p