University of Medicine and Dentistry of New Jersey

About: University of Medicine and Dentistry of New Jersey is a based out in . It is known for research contribution in the topics: Population & Pregnancy. The organization has 14634 authors who have published 19610 publications receiving 1041794 citations.

To Arrest or Not To G2-M Cell-Cycle Arrest

Abstract: Cells transverse the cell-cycle in several well-controlled phases [(1)][1] . In the G1 phase, cells commit to enter the cell-cycle and prepare to duplicate their DNA in S phase. After S phase, cells enter the G2 phase, where repair might occur along with preparation for mitosis in M phase. In the M

Chemotherapeutics and Radiation Stimulate MHC Class I Expression through Elevated Interferon-beta Signaling in Breast Cancer Cells

Abstract: Low doses of anticancer drugs have been shown to enhance antitumor immune response and increase the efficacy of immunotherapy. The molecular basis for such effects remains elusive, although selective depletion of T regulatory cells has been demonstrated. In the current studies, we demonstrate that topotecan (TPT), a topoisomerase I-targeting drug with a well-defined mechanism of action, stimulates major histocompatibility complex class I (MHC I) expression in breast cancer cells through elevated expression/secretion of interferon-β (IFN-β) and activation of type I IFN signaling. First, we show that TPT treatment elevates the expression of both total and cell-surface MHC I in breast cancer cells. Second, conditioned media from TPT-treated breast cancer ZR-75-1 cells induce elevated expression of cell-surface MHC I in drug-naive recipient cells, suggesting the involvement of cytokines and/or other secreted molecules. Consistently, TPT-treated cells exhibit elevated expression of multiple cytokines such as IFN-β, TNF-α, IL-6 and IL-8. Third, either knocking down the type I interferon receptor subunit 1 (IFNAR1) or addition of neutralizing antibody against IFN-β results in reduced MHC I expression in TPT-treated cells. Together, these results suggest that TPT induces increased IFN-β autocrine/paracrine signaling through type I IFN receptor, resulting in the elevated MHC I expression in tumor cells. Studies have also demonstrated that other chemotherapeutic agents (e.g. etoposide, cisplatin, paclitaxel and vinblastine) similarly induce increased IFN-β secretion and elevated MHC I expression. In addition, conditioned media from γ-irradiated donor cells are shown to induce IFN-β-dependent MHC I expression in unirradiated recipient cells. In the aggregate, our results suggest that many cancer therapeutics induce elevated tumor antigen presentation through MHC I, which could represent a common mechanism for enhanced antitumor immune response through T cell cytotoxicity during metronomic chemotherapy, as well as increased efficacy of combined chemo- (or radio-)/immuno-therapy.

The inhibition of low-density lipoprotein oxidation by 17-β estradiol

Abstract: The antioxidant activities of 17-β-estradiol (E2) and other steroid hormones were studied by determining their effect on copper-catalyzed (cell-free) and mononuclear cell-mediated oxidation of low-density lipoproteins (LDL), as measured by the production of thiobarbituric acid-reactive substances (TBARS). The oxidation of LDL increased linearly with copper concentrations ranging from 0 to 10 μmol/L. E2 at a concentration of 1 μmol/L inhibited LDL oxidation by 37% to 62% at the various concentrations of copper. In a time-course study, E2 at 1 μmol/L delayed the onset of LDL oxidation in the presence of 5 μmol/L copper. E2 (1 μmol/L) inhibited TBARS production catalyzed by 5 μmol/L copper by 54%, compared with 60% inhibition by 1 μmol/L butylated hydroxytoluene (BHT), a known inhibitor of lipid peroxidation. Estriol at 5 μmol/L decreased LDL oxidation by 49%. Dehydroepiandrosterone (DHEA), testosterone, and estrone had no significant effects. E2 was also an effective inhibitor of mononuclear cell (MNC)-mediated oxidation of LDL, but had no effect on superoxide production by these cells. The onset of TBARS formation from cell-mediated LDL oxidation was also delayed by incubation with 1 μmol/L E2. The results indicate that estrogen may protect against atherosclerosis by inhibiting lipoprotein oxidation.

Methylthioadenosine/S-adenosylhomocysteine nucleosidase, a critical enzyme for bacterial metabolism

Abstract: The importance of methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidase in bacteria has started to be appreciated only in the past decade. A comprehensive analysis of its various roles here demonstrates that it is an integral component of the activated methyl cycle, which recycles adenine and methionine through S-adenosylmethionine (SAM)-mediated methylation reactions, and also produces the universal quorum-sensing signal, autoinducer-2 (AI-2). SAM is also essential for synthesis of polyamines, N-acylhomoserine lactone (autoinducer-1), and production of vitamins and other biomolecules formed by SAM radical reactions. MTA, SAH and 5'-deoxyadenosine (5'dADO) are product inhibitors of these reactions, and are substrates of MTA/SAH nucleosidase, underscoring its importance in a wide array of metabolic reactions. Inhibition of this enzyme by certain substrate analogues also limits synthesis of autoinducers and hence causes reduction in biofilm formation and may attenuate virulence. Interestingly, the inhibitors of MTA/SAH nucleosidase are very effective against the Lyme disease causing spirochaete, Borrelia burgdorferi, which uniquely expresses three homologous functional enzymes. These results indicate that inhibition of this enzyme can affect growth of different bacteria by affecting different mechanisms. Therefore, new inhibitors are currently being explored for development of potential novel broad-spectrum antimicrobials.