Antitumor Effects of a Sesquiterpene Derivative from Marine Sponge in Human Breast Cancer Cells

In this study, the anti-proliferative effect of ilimaquinone, a sesquiterpene derivative from the marine sponge, in breast cancer cells was investigated. Ilimaquinone inhibited the proliferation of MCF-7 and MDA-MB-231 breast cancer cells with IC50 values of 10.6 μM and 13.5 μM, respectively. Non-tumorigenic human breast epithelial cells were less sensitive to ilimaquinone than breast cancer cells. Flow cytometric and Western blot analysis showed that ilimaquinone induced S-phase arrest by modulating the expression of p-CDC-2 and p21. Ilimaquinone induces apoptosis, which is accompanied by multiple biological biomarkers, including the downregulation of Akt, ERK, and Bax, upregulation of p38, loss of mitochondrial membrane potential, increased reactive oxygen species generation, and induced autophagy. Collectively, these findings suggest that ilimaquinone causes cell cycle arrest as well as induces apoptosis and autophagy in breast cancer cells.

742. “Troponin Leaks” in Patients with Acute Respiratory Viral Infections Enrolled in SUPERNOVA: A Marker of Worse Clinical Outcomes

Background Cardiac troponin I (cTnI) is a specific marker of cardiac muscular injury. Many patients hospitalized with acute respiratory illness (ARI) have elevated cTnI levels but do not meet EKG criteria for an acute ischemic cardiac event. Troponin leaks could be due to demand ischemia or acute inflammation of the myocardium. We hypothesized that patients with viral ARI and elevated cTnI have worse cardiopulmonary outcomes than those with viral ARI and normal cTnI. Methods From November 11, 2016–September 30, 2017 nasopharyngeal swabs from patients enrolled in SUPERNOVA ARI Study, a CDC/2-VA site, active surveillance platform to evaluate the incidence of viral infection in patients hospitalized with symptoms and/or signs of ARI, were tested using a FilmArray Respiratory Panel. Based on detection of any virus, patients were categorized as positive (vPCR+) or negative (vPCR−). Patient enrolled at the Houston site with cTnI obtained <48 hours of admission were included in the analysis. cTnI above upper limit of normal (>0.03 ng/dL) was defined as elevated. Demographic and clinical data were abstracted from chart review. Outcomes were myocardial infarction (MI) on admission, 30- and 90-day re-admissions due to cardio-respiratory illness and 30- and 90-day all-cause mortality. For the univariable analysis of baseline factors and outcomes we used unpaired t-tests for continuous variables and χ2 or Fisher exact test for categorical variables as appropriate. Results Ninety-four of 332 cases were vPCR positive and cTnI levels on admission were available in 86. Demographics and comorbidities were all similar for the high (N = 42) and normal (N = 44) cTnI groups. Compared with normal cTnI group, those with high cTnI had similar 30- and 90-day readmission rates (14% vs. 9%, P = 0.4 and 26% vs. 16%, respectively, P = 0.2). However, 30- and 90-day mortality rates were higher for high cTnI patients (10% vs. 0% and 19% vs. 5%, P < 0.03). Conclusion Troponin elevation on patients with a documented viral respiratory infection is associated with higher 30- and 90-day mortality rates. Troponin leaks should not be dismissed as a trivial finding in this group of patients. Further work on its pathogenesis is warranted. Disclosures All authors: No reported disclosures.

Corydalis yanhusuo W.T. Wang Extract Inhibits MCF-7 Cell Proliferation by Inducing Cell Cycle G2/M Arrest

Corydalis yanhusuo W.T. Wang (YHS) is a traditional Chinese herb widely prescribed for promoting blood circulation, reinforcing vital energy and alleviating pain. Our previous studies showed that an ethanol extract of YHS inhibits metastasis of breast cancer cells in vitro. In the present study, the anti-proliferative effect of the extract was determined by MTT assay and the LDH release was measured with a commercial kit. Intracellular reactive oxygen species (ROS) production and mitochondrial membrane potential (ΔΨm) were monitored by CM- H2DCF-DA and JC-1 staining, respectively. Cell cycle was analyzed with propidium iodide (PI) staining by flow cytometry and protein expressions were measured by Western blotting. The YHS extract significantly inhibited MCF-7 cell proliferation in a dose-dependent manner. Significant increase of ROS formation and decrease of ΔΨm were observed. Furthermore, it induced MCF-7 cell cycle arrest at the G2/M phases. In addition, the p-cdc-2/cdc-2 protein expression ratio was increased while Rb and p21 protein expressions were decreased. The YHS extract inhibited MCF-7 proliferation by inducing G2/M cell cycle arrest, which might be mediated by inducing ROS formation, decreasing ΔΨm and regulating cell cycle related protein expressions.

The NDR Kinase DBF-2 Is Involved in Regulation of Mitosis, Conidial Development, and Glycogen Metabolism in Neurospora crassa

ABSTRACT Neurospora crassa dbf-2 encodes an NDR (nuclear Dbf2-related) protein kinase, homologous to LATS1, a core component of the Hippo pathway. This pathway plays important roles in restraining cell proliferation and promoting apoptosis in differentiating cells. Here, we demonstrate that DBF-2 is involved in three fundamental processes in a filamentous fungus: cell cycle regulation, glycogen biosynthesis, and conidiation. DBF-2 is predominantly localized to the nucleus, and most (approximately 60%) dbf-2 null mutant nuclei are delayed in mitosis, indicating that DBF-2 activity is required for properly completing the cell cycle. The dbf-2 mutant exhibits reduced basal hyphal extension rates accompanied by a carbon/nitrogen ratio-dependent bursting of hyphal tips, vast glycogen leakage, defects in aerial hypha formation, and impairment of all three asexual conidiation pathways in N. crassa. Our findings also indicate that DBF-2 is essential for sexual reproduction in a filamentous fungus. Defects in other Hippo and glycogen metabolism pathway components (mob-1, ccr-4, mst-1, and gsk-3) share similar phenotypes such as mitotic delay and decreased CDC-2 (cell division cycle 2) protein levels, massive hyphal swellings, hyphal tip bursting, glycogen leakage, and impaired conidiation. We propose that DBF-2 functions as a link between Hippo and glycogen metabolism pathways.

Molecular characterization and analysis of a gene encoding the acidic repeat protein (Arp) of Treponema pallidum

The acidic repeat protein (arp) genes from three subspecies of the treponeme Treponema pallidum (T. pallidum subsp. pallidum, Nichols strain; T. pallidum subsp. pertenue, CDC-1 and CDC-2 strains; and T. pallidum subsp. endemicum, Bosnia A strain) were cloned and sequenced. The predicted protein sequence contained a high percentage of glutamic acid, hence the name acidic repeat protein, or Arp. The protein had a potential membrane-spanning domain and a signal peptidase I site. The gene from the Nichols strain of T. pallidum subsp. pallidum contained a set of 14 nearly identical repeats of a 60 bp sequence, which occupied ∼51 % of the length of the gene. Analyses of arp from laboratory strains showed that the 5′ and 3′ ends of the genes were conserved, but there was considerable heterogeneity in the number of repeats of this 60 bp sequence. Based on amino acid variations, the 14 sequence repeats could be classified into three types, which were named type I, type II and type III repeats. The type II repeat was the most common in the strains examined. The arp gene of the Nichols strain was subsequently cloned into the expression vector pBAD/TOPO ThioFusion. The expressed protein was detected in a Western blot assay using rabbit immune sera produced against T. pallidum, or synthetic peptides derived from the repeat sequences. Using an ELISA, rapid plasma reagin (RPR) test-positive sera reacted with synthetic peptides derived from the repeat region but not with peptides derived from N and C termini of the Arp protein. These results show that the Arp protein is immunogenic and could prove to be a useful target for serological diagnosis of T. pallidum infection.