Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

Microbial culture conditions in the laboratory, which conventionally involve the cultivation of one strain in one culture vessel, are vastly different from natural microbial environments. Even though perfectly mimicking natural microbial interactions is virtually impossible, the cocultivation of multiple microbial strains is a reasonable strategy to induce the production of secondary metabolites, which enables the discovery of new bioactive natural products. Our coculture of marine Streptomyces and Bacillus strains isolated together from an intertidal mudflat led to discover a new metabolite, dentigerumycin E (1). Dentigerumycin E was determined to be a new cyclic hexapeptide incorporating three piperazic acids, N-OH-Thr, N-OH-Gly, β-OH-Leu, and a pyran-bearing polyketide acyl chain mainly by analysis of its NMR and MS spectroscopic data. The putative PKS-NRPS biosynthetic gene cluster for dentigerumycin E was found in the Streptomyces strain, providing clear evidence that this cyclic peptide is produced by the Streptomyces strain. The absolute configuration of dentigerumycin E was established based on the advanced Marfey's method, ROESY NMR correlations, and analysis of the amino acid sequence of the ketoreductase domain in the biosynthetic gene cluster. In biological evaluation of dentigerumycin E (1) and its chemical derivatives [2-N,16-N-deoxydenteigerumycin E (2) and dentigerumycin methyl ester (3)], only dentigerumycin E exhibited antiproliferative and antimetastatic activities against human cancer cells, indicating that N-OH and carboxylic acid functional groups are essential for the biological activity

Antitumor Activity of Rutaecarpine in Human Colorectal Cancer Cells by Suppression of Wnt/beta-Catenin Signaling

Alkaloids derived from natural products have been traditionally used to treat various diseases, including cancers. Rutaecarpine (1), a beta-carboline-type alkaloid obtained from Evodia rutaecarpa, has been previously reported as an anti-inflammatory agent. Nonetheless, its anticancer activity and the underlying molecular mechanisms remain to be explored. In the procurement of Wnt/beta-catenin inhibitors from natural alkaloids, 1 was found to exhibit activity against the Wnt/beta-catenin-response reporter gene. Since the abnormal activation of Wnt/beta-catenin signaling is highly involved in colon carcinogenesis, the antitumor activity and molecular mechanisms of 1 were investigated in colorectal cancer (CRC) cells. The antiproliferative activity of 1 was associated with the suppression of the Wnt/beta-catenin-mediated signaling pathway and its target gene expression in human CRC cells. 1 also induced G(0)/G(1) cell cycle arrest and apoptotic cell death, and the antimigration and anti-invasion potential of 1 was confirmed through epithelial-mesenchymal transition biomarker inhibition by the regulation of Wnt signaling. The antitumor activity of 1 was supported in an Ls174T-implanted xenograft mouse model via Wnt target gene regulation. Overall, these findings suggest that targeting the Wnt/beta-catenin signaling pathway by 1 is a promising therapeutic option for the treatment of human CRC harboring beta-catenin mutation.N

Inhibition of DOT1L by Half-Selenopsammaplin A Analogs Suppresses Tumor Growth and EMT-Mediated Metastasis in Triple-Negative Breast Cancer

Due to a lack of hormone receptors, current treatment strategies for triple-negative breast cancer (TNBC) are limited with frequent disease recurrence and metastasis. Recent findings have suggested that aberrant methylation of histone H3 lysine 79 residue (H3K79me) by the histone methyltransferase disruptor of telomeric silencing 1-like (DOT1L) is a potential therapeutic target for TNBC clinical management. Therefore, we developed DOT1L inhibitors as potential antitumor agents against TNBC cells. We reveal that a synthetic half-selenopsammaplin A analog 9l (subsequently known as 9l) exhibited inhibitory activity against DOT1L-mediated H3K79 methylation, and showed antitumor activity in TNBC cells. The analog 9l also significantly inhibited TNBC invasion and migration via the modulation of epithelial-mesenchymal transition (EMT) markers, including N-cadherin and vimentin downregulation and E-cadherin upregulation. In an MDA-MB-231/Luc-implanted orthotopic mouse metastasis model, treatment with 9l effectively inhibited tumor growth and lung metastasis via DOT1L regulatory activity and EMT processes. Taken together, these findings highlight the potential of 9l as a novel therapeutic candidate for treating metastatic TNBC via DOT1L modulation

Depsidomycins B and C: New Cyclic Peptides from a Ginseng Farm Soil-Derived Actinomycete

LC/MS-based chemical profiling of a ginseng farm soil-derived actinomycete strain, Streptomyces sp. BYK1371, enabled the discovery of two new cyclic heptapeptides, depsidomycins B and C (1 and 2), each containing two piperazic acid units and a formyl group at their N-terminus. The structures of 1 and 2 were elucidated by a combination of spectroscopic and chemical analyses. These new compounds were determined to possess d-leucine, d-threonine, d-valine, and S-piperazic acid based on the advanced Marfey’s method and a GITC (2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate) derivatization of their hydrolysates, followed by LC/MS analysis. Depsidomycins B and C displayed significant antimetastatic activities against metastatic breast cancer cells (MDA-MB-231)

Data_Sheet_1_Different decision-making in spine metastasis management among radiation oncologists and orthopedic surgeons: a Korean online survey study.pdf

PurposeTo understand the current practice of radiation oncologists (ROs) and orthopedic surgeons (OSs) regarding spine metastasis.MethodsIn 2022, an internet-based survey was conducted for ROs and OSs who treat spinal metastasis in Korea. Respondents were asked to choose the treatment option for two clinical scenarios. Scenario 1 involved a case displaying symptoms of leg weakness due to spinal cord compression and Scenario 2 involved a case with back pain due to pathologic compression fracture. The survey also included a question that required respondents to rank the importance of 11 clinical factors that affect treatment decisions.ResultsForty-nine ROs and 30 OSs responded to the survey. There were significant differences in treatment choices between two groups for both scenarios (P = 0.001). In Scenario 1, more OSs chose surgical resection than ROs (43.3% vs. 16.7%), while more ROs chose radiotherapy than OSs (83.3% vs. 53.3%). In Scenario 2, a similar proportion of OSs and ROs chose radiotherapy (OSs, 71.4% vs. ROs, 67.3%), while more OSs opted for prophylactic fixation after radiotherapy than ROs (95.0% vs. 42.4%). The top three factors influencing treatment decisions were general performance status, life expectancy, and spinal instability for both ROs and OSs. In both Scenarios 1 and 2, the treatment decisions of ROs changed significantly when clinical conditions related to these top three factors were altered.ConclusionAlthough ROs and OSs share the same factors influencing treatment decisions for spinal metastases, notable differences exist in their actual treatment preferences, with ROs preferring radiotherapy and OSs opting for surgical resection. Multidisciplinary discussions may be necessary to reduce the gap in decision-making.</p

Discovery of a Novel Template, 7-Substituted 7-Deaza-4&prime;-Thioadenosine Derivatives as Multi-Kinase Inhibitors

The development of anticancer drugs remains challenging owing to the potential for drug resistance. The simultaneous inhibition of multiple targets involved in cancer could overcome resistance, and these agents would exhibit higher potency than single-target inhibitors. Protein kinases represent a promising target for the development of anticancer agents. As most multi-kinase inhibitors are heterocycles occupying only the hinge and hydrophobic region in the ATP binding site, we aimed to design multi-kinase inhibitors that would occupy the ribose pocket, along with the hinge and hydrophobic region, based on ATP-kinase interactions. Herein, we report the discovery of a novel 4&prime;-thionucleoside template as a multi-kinase inhibitor with potent anticancer activity. The in vitro evaluation revealed a lead 1g (7-acetylene-7-deaza-4&prime;-thioadenosine) with potent anticancer activity, and marked inhibition of TRKA, CK1&delta;, and DYRK1A/1B kinases in the kinome scan assay. We believe that these findings will pave the way for developing anticancer drugs

Cyclopeptides from the Sponge <i>Stylissa flabelliformis</i>

Three new cyclopeptides, phakellistatins 20–22 (<b>1</b>–<b>3</b>), as well as 10 known cyclopeptides of the same structural class were isolated from the tropical sponge <i>Stylissa flabelliformis</i>. By a combination of chemical and spectroscopic methods, the structures of the new compounds were determined to be an epimeric mixture of cycloheptapeptides (<b>1</b>) and two epimeric cyclodecapeptides (<b>2</b> and <b>3</b>) related to the phakellistatins. The cyclopeptides were evaluated for <i>in vitro</i> cytotoxicity against a variety of cancer cell lines, and compounds <b>2</b> and <b>3</b> exhibited significant activity

Chemical Specification of E3 Ubiquitin Ligase Engagement by Cysteine-Reactive Chemistry

Targeted protein degradation relies on small molecules that induce new protein–protein interactions between targets and the cellular protein degradation machinery. Most of these small molecules feature specific ligands for ubiquitin ligases. Recently, the attachment of cysteine-reactive chemical groups to pre-existing small molecule inhibitors has been shown to drive specific target degradation. We demonstrate here that different cysteine-reactive groups can specify target degradation via distinct ubiquitin ligases. By focusing on the bromodomain ligand JQ1, we identify cysteine-reactive functional groups that drive BRD4 degradation by either DCAF16 or DCAF11. Unlike proteolysis-targeting chimeric molecules (PROTACs), the new compounds use a single small molecule ligand with a well-positioned cysteine-reactive group to induce protein degradation. The finding that nearly identical compounds can engage multiple ubiquitination pathways suggests that targeting cellular pathways that search for and eliminate chemically reactive proteins is a feasible avenue for converting existing small molecule drugs into protein degrader molecules