Gestational choriocarcinoma with inferior vena cava (IVC) tumor thrombus formation is exceedingly rare. We report a case initially presenting with recurrent nausea and vomiting in a 52-year-old woman. Laboratory studies revealed elevated serum β-hCG levels, and ultrasonography demonstrated a pelvic mass extending from the parametrial area into the IVC. Pathological examination of a pelvic mass biopsy confirmed the diagnosis of choriocarcinoma. Further assessment identified pulmonary hypertension and emboli within small pulmonary artery branches. The patient received EMA-CO chemotherapy and achieved complete remission, with no evidence of recurrence during a one-year follow-up. This case highlights the diagnostic challenges posed by non-classical metastases and underscores the importance of considering choriocarcinoma in the differential diagnosis of women with a pregnancy history and unexplained systemic symptoms.

Fifteen new actinomycin analogs were obtained from the marine-derived Streptomyces polyantibioticus S4D258. Structural elucidation of these compounds was successfully achieved by comprehensive analysis of high-resolution electrospray ionization mass spectrometry (HR-ESIMS), nuclear magnetic resonance spectroscopy (NMR), and Marfey's method. Notably, actinomycins H1-H5 (1-5) contain L-serine (L-Ser), D-2-aminobutyric acid (D-2-Aba), and L-2-methylaminobutyric acid (L-2-MeAba) residues, whereas actinomycin H6 (6) comprises a 5H-oxazolo[4,5-b]phenoxazine chromophore. Actinomycins H7-H15 (7-15) are nine truncated actinomycin analogs only containing one pentapeptidolactone unit. Actinomycins H1 (1) and H9 (9) exhibited inhibitory activities against the proliferation of triple-negative breast cancer MDA-MB-231 cells with IC50 values of 28.00 nM and 4.34 µM, respectively. Mechanistic investigation revealed that the above two actinomycin analogs not only induce S-phase arrest, mitochondrial membrane potential depolarization, and apoptosis, but also trigger ferroptosis, as revealed by an increase in the level of reactive oxygen species, lipid peroxidation, and malondialdehyde. Collectively, our findings enriched the structural diversity of natural actinomycins and inspired the re-examination of actinomycin analogs as anticancer leads against triple-negative breast cancer.

The nucleolus is a dynamic membraneless organelle where ribosomal RNA (rRNA) transcription, processing, and ribonucleoprotein assembly occur. Visualizing nascent RNA within nucleolar condensates reveals how RNA metabolism and phase separation reorganize under stress. This chapter provides a practical protocol to label nascent RNA using 5-ethynyl uridine (5-EU), followed by copper-catalyzed azide-alkyne cycloaddition for fluorescent detection. The method is straightforward, works across mammalian cells, and robustly reports nucleolar transcription under basal and stress conditions (heat shock; low-dose actinomycin D). Step-by-step instructions, reagent setup, image analysis metrics, troubleshooting, safety, and expected results are included so that researchers can reproducibly implement the assay.

MicroRNAs (miRNAs) are critical post-transcriptional regulators that function through association with Argonaute proteins to form the RNA-induced silencing complex (RISC). Although miRNAs were considered remarkably stable molecules, their cellular abundance is subject to active regulation through coordinated degradation pathways. Precise quantification of miRNA stability remains technically challenging, primarily owing to the small size of these molecules, their elevated GC content, and their relatively low abundance compared to other cellular RNA species. To overcome these technical limitations, this chapter provides a comprehensive experimental strategy for monitoring miRNA stability using optimized northern blotting techniques. This approach integrates transcriptional shutoff through actinomycin D treatment with advanced detection chemistries-specifically, EDC-mediated crosslinking and near-infrared fluorescent probe hybridization-to markedly enhance signal resolution and detection sensitivity, thereby facilitating precise determination of decay kinetics and reliable calculation of miRNA half-lives. Collectively, this method offers high specificity, enhanced sensitivity, and quantitative accuracy to investigate miRNA degradation dynamics at single-species resolution.

Actinomycins constitute a class of bioactive compounds known for their potent cytotoxic properties. Among them, actinomycin D, isolated in the 1940s from Streptomyces antibioticus, is the most extensively studied derivative. Structurally, actinomycins are characterized by a planar phenoxazinone chromophore flanked by two cyclic pentapeptides. They exert their biological effects primarily through DNA intercalation and transcription inhibition. Despite its remarkable bioactivity, the clinical application of actinomycin D is limited by significant adverse effects, including hepatotoxicity and restricted selectivity. These limitations underscore the need for structurally optimized analogs with improved therapeutic profiles and reduced toxicity. Over the decades, natural product discovery, precursor-directed biosynthesis, and synthetic modification have yielded more than 70 structurally distinct derivatives, incorporating variations in both the peptide rings and the chromophore core. These structural modifications have resulted in diverse antibacterial, antiviral, and cytotoxic activities. Thus, this review critically examines the historical development, chemical diversity, and in vitro and preclinical bioactivity of actinomycin derivatives, highlighting key structural modifications over time and discussing their implications for future drug development.

Pyoverdines are fluorescent siderophores and potential virulence factors produced by Pseudomonas bacteria. Actinomycin D has been reported to inhibit pyoverdine production; however, its strong cytotoxicity limits its use as a probe to elucidate pyoverdine function. In this study, we synthesized actinomycin analogs (1-4) with a modified phenoxazine moiety. To enable convergent syntheses, the threonine residues were replaced with 2,3-diaminopropionic acid. Compounds 1-4 showed negligible to low cytotoxicity toward HHUA endometrial cancer cells. However, only 4, with the same phenoxazine ring as actinomycin D, retained inhibitory activity against pyoverdine production by Pseudomonas fluorescence NBRC15833, although an order of magnitude lower than actinomycin D. These results suggest that the phenoxazine ring would be essential to the cytotoxicity and pyoverdine production inhibitory activity, and the further modification of the cyclic peptide moiety is necessary to understand the structure-activity relationship underlying pyoverdine production inhibition.

Organelles have been reported to be closely associated with tumor development and progression, but their role in osteosarcoma (OS) remains largely unexplored. Organelle related genes (ORGs) associated with OS prognosis were identified using Cox regression analysis. A prognostic model was subsequently constructed through multivariate Cox regression analysis and validated using an independent dataset. Patients were stratified into high-risk and low-risk groups based on the median risk score. In addition, immune infiltration analysis, enrichment analysis and drug sensitivity evaluation were performed. Finally, in vitro experiments were conducted to validate the potential roles of ORGs in OS. We identified 3 ORGs (ACSS2, CLTCL1, and PLD3) that were significantly associated with OS prognosis. A novel 3 ORG signature was established, which effectively stratified patients into high-risk and low-risk groups with distinct survival outcomes. This signature served as an independent prognostic factor. The areas under the receiver operating characteristic (ROC) curve for the 1-, 4-, and 7-year survival rates were 0.66, 0.74, and 0.83, respectively. These findings were further validated using the independent GSE21257 dataset, where the corresponding ROC curve values for the 1-, 4-, and 7-year survival rates were 0.71, 0.80, and 0.68, respectively. Drug sensitivity analysis revealed differential responses to 4 drugs between the risk groups, with the 3 ORGs (ACSS2, CLTCL1 and PLD3) showing positive correlations with 2 drugs (BI_2536, Dactinomycin). Additionally, functional experiments confirmed the role of ACSS2 in OS cell behavior. This novel ORG signature not only provides a valuable tool for patient stratification but also offers insights into the biological processes driving OS progression and potential therapeutic targets.