Constituents of Aplysina Fistularis

533 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1979.The constituents of three species of a marine sponge, Aplysina fistularis, were examined by gas chromatography/mass spectrometry (GC/MS), high pressure liquid chromatography (HPLC) and classical fractionation and purification procedures. GC/MS indicated that many brominated tyrosine metabolites were accumulated in two A. fistularis samples, #852 and #947. By employing this technique, brominated hydroquinones; brominated phenylacetonitriles; brominated phenylacetamides; aeroplysinins; brominated 2-hydroxy-4-methoxyphenylacetic acid lactones; 2,6-dibromo-4-hydroxy-2,5-cyclohexadienone-4-acetamide, its monobromo analog and its ketals; and brominated phenylacetic acids were identified in the extracts of samples #852 and #947.HPLC study of sample #852 gave identified and allowed isolation of several brominated tyrosine metabolites. Antimicrobial activity of this sample was mostly due to aeroplysinin-1, 2,6-dibromo-4-hydroxy-2,5-cyclohexadienone-4-acetamide and the acetic acid analog of the latter.Fractionation and purification of the extract of sample #947 on a large scale gave aerothionin as a major constituent. Attempts to isolate antimicrobial compounds in this extract were unsuccessful.Purification of the antimicrobial principles of sample IBE-12-III-77-1-3 gave two major antimicrobial compounds (2,6-dibromo-4-hydroxy-2,5-cyclohexadienone-4-acetamide and 2,6-dibromo-4-hydroxy-2-cyclohexenone-4-acetamide-5N-lactam). The latter was previously unidentified natural product with strong, broad antimicrobial activity. Dichloro and bromochloro analogs of both compounds were also identified.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Cytokeratin 19 (KRT19) has a Role in the Reprogramming of Cancer Stem Cell-Like Cells to Less Aggressive and More Drug-Sensitive Cells

Cytokeratin 19 (KRT19) is a cytoplasmic intermediate filament protein, which is responsible for structural rigidity and multipurpose scaffolds. In several cancers, KRT19 is overexpressed and may play a crucial role in tumorigenic transformation. In our previous study, we revealed the role of KRT19 as signaling component which mediated Wnt/NOTCH crosstalk through NUMB transcription in breast cancer. Here, we investigated the function of KRT19 in cancer reprogramming and drug resistance in breast cancer cells. We found that expression of KRT19 was attenuated in several patients-derived breast cancer tissues and patients with a low expression of KRT19 were significantly correlated with poor prognosis in breast cancer patients. Consistently, highly aggressive and drug-resistant breast cancer patient-derived cancer stem cell-like cells (konkuk university-cancer stem cell-like cell (KU-CSLCs)) displayed higher expression of cancer stem cell (CSC) markers, including ALDH1, CXCR4, and CD133, but a much lower expression of KRT19 than that is seen in highly aggressive triple negative breast cancer MDA-MB231 cells. Moreover, we revealed that the knockdown of KRT19 in MDA-MB231 cells led to an enhancement of cancer properties, such as cell proliferation, sphere formation, migration, and drug resistance, while the overexpression of KRT19 in KU-CSLCs resulted in the significant attenuation of cancer properties. KRT19 regulated cancer stem cell reprogramming by modulating the expression of cancer stem cell markers (ALDH1, CXCR4, and CD133), as well as the phosphorylation of Src and GSK3β (Tyr216). Therefore, our data may imply that the modulation of KRT19 expression could be involved in cancer stem cell reprogramming and drug sensitivity, which might have clinical implications for cancer or cancer stem cell treatment

Valproic Acid Induces Endocytosis-Mediated Doxorubicin Internalization and Shows Synergistic Cytotoxic Effects in Hepatocellular Carcinoma Cells

Valproic acid (VPA), a well-known histone deacetylase (HDAC) inhibitor, is used as an anti-cancer drug for various cancers, but the synergistic anti-cancer effect of VPA and doxorubicin (DOX) combination treatment and its potential underlying mechanism in hepatocellular carcinoma (HCC) remain to be elucidated. Here, we evaluate the mono- and combination-therapy effects of VPA and DOX in HCC and identify a specific and efficient, synergistic anti-proliferative effect of the VPA and DOX combination in HCC cells, especially HepG2 cells; this effect was not apparent in MIHA cells, a normal hepatocyte cell line. The calculation of the coefficient of drug interaction confirmed the significant synergistic effect of the combination treatment. Concurrently, the synergistic apoptotic cell death caused by the VPA and DOX combination treatment was confirmed by Hoechst nuclear staining and Western blot analysis of caspase-3 and poly (ADP-ribose) polymerase (PARP) activation. Co-treatment with VPA and DOX enhanced reactive oxygen species (ROS) generation and autophagy, which were clearly attenuated by ROS and autophagy inhibitors, respectively. Furthermore, as an indication of the mechanism underlying the synergistic effect, we observed that DOX internalization, which was induced in the VPA and DOX combination-treated group, occurred via by the caveolae-mediated endocytosis pathway. Taken together, our study uncovered the potential effect of the VPA and DOX combination treatment with regard to cell death, including induction of cellular ROS, autophagy, and the caveolae-mediated endocytosis pathway. Therefore, these results present novel implications in drug delivery research for the treatment of HCC