Transcriptomic and proteomic study of cancer cell lines exposed to actinomycin D and nutlin-3a reveals numerous, novel candidates for p53-regulated genes.

Transcriptomic analyses have revealed hundreds of p53-regulated genes; however, these studies used a limited number of cell lines and p53-activating agents. Therefore, we searched for candidate p53-target genes by employing stress factors and cell lines never before used in a high-throughput search for p53-regulated genes. We performed RNA-Seq on A549 cells exposed to camptothecin, actinomycin D, nutlin-3a, as well as a combination of actinomycin D and nutlin-3a (A + N). The latter two substances synergise upon the activation of selected p53-target genes. A similar analysis was performed on other cell lines (U-2 OS, NCI-H460, A375) exposed to A + N. To identify proteins in cell lysates or those secreted into a medium of A549 cells in control conditions or treated with A + N, we employed mass spectrometry. The expression of selected genes strongly upregulated by A + N or camptothecin was examined by RT-PCR in p53-deficient cells and their controls. We found that p53 participates in the upregulation of: ACP5, APOL3, CDH3, CIBAR2, CRABP2, CTHRC1, CTSH, FAM13C, FBXO2, FRMD8, FRZB, GAST, ICOSLG, KANK3, KCNK6, KLRG2, MAFB, MR1, NDRG4, PTAFR, RETSAT, TMEM52, TNFRSF14, TRANK1, TYSND1, WFDC2, WFDC5, WNT4 genes. Twelve of these proteins were detected in the secretome and/or proteome of treated cells. Our data generated new hypotheses concerning the functioning of p53. Many genes activated by A + N or camptothecin are also activated by interferons, indicating a noticeable overlap between transcriptional programs of p53 and these antiviral cytokines. Moreover, several identified genes code for antagonists of WNT/ß-catenin signalling pathways, which suggests new connections between these two cancer-related signalling systems. One of these antagonists is DRAXIN. Previously, we found that its gene is activated by p53. In this study, using mass spectrometry and Western blotting, we detected expression of DRAXIN in a medium of A549 cells exposed to A + N. Thus, this protein functions not only in the development of the nervous system, but it may also have a new cancer-related function.

Deficiency of Acetyltransferase nat10 in Zebrafish Causes Developmental Defects in the Visual Function.

Purpose: N4-acetylcytidine (ac4C) is a post-transcriptional RNA modification catalyzed by N-acetyltransferase 10 (NAT10), a critical factor known to influence mRNA stability. However, the role of ac4C in visual development remains unexplored. Methods: Analysis of public datasets and immunohistochemical staining were conducted to assess the expression pattern of nat10 in zebrafish. We used CRISPR/Cas9 and RNAi technologies to knockout (KO) and knockdown (KD) nat10, the zebrafish ortholog of human NAT10, and evaluated its effects on early development. To assess the impact of nat10 knockdown on visual function, we performed comprehensive histological evaluations and behavioral analyses. Transcriptome profiling and real-time (RT)-PCR were utilized to detect alterations in gene expression resulting from the nat10 knockdown. Dot-blot and RNA immunoprecipitation (RIP)-PCR analyses were conducted to verify changes in ac4C levels in both total RNA and opsin mRNA specifically. Additionally, we used the actinomycin D assay to examine the stability of opsin mRNA following the nat10 KD. Results: Our study found that the zebrafish NAT10 protein shares similar structural properties with its human counterpart. We observed that the nat10 gene was prominently expressed in the visual system during early zebrafish development. A deficiency of nat10 in zebrafish embryos resulted in increased mortality and developmental abnormalities. Behavioral and histological assessments indicated significant vision impairment in nat10 KD zebrafish. Transcriptomic analysis and RT-PCR identified substantial downregulation of retinal transcripts related to phototransduction, light response, photoreceptors, and visual perception in the nat10 KD group. Dot-blot and RIP-PCR analyses confirmed a pronounced reduction in ac4C levels in both total RNA and specifically in opsin messenger RNA (mRNA). Additionally, by evaluating mRNA decay in zebrafish treated with actinomycin D, we observed a significant decrease in the stability of opsin mRNA in the nat10 KD group. Conclusions: The ac4C-mediated mRNA modification plays an essential role in maintaining visual development and retinal function. The loss of NAT10-mediated ac4C modification results in significant disruptions to these processes, underlining the importance of this RNA modification in ocular development.

Antibacterial Mechanism, Control Efficiency, and Nontarget Toxicity Evaluation of Actinomycin X2 against Xanthomonas citri Subsp. citri.

The present study investigated the antibacterial mechanism, control efficiency, and nontarget toxicity of actinomycin X2 (Act-X2) against Xanthomonas citri subsp. citri (Xcc) for the first time. Act-X2 almost completely inhibited the proliferation of Xcc in the growth curve assay at a concentration of 0.25 MIC (minimum inhibitory concentration, MIC = 31.25 µg/mL). This inhibitory effect was achieved by increasing the production of reactive oxygen species (ROS), blocking the formation of biofilms, obstructing the synthesis of intracellular proteins, and decreasing the enzymatic activities of malate dehydrogenase (MDH) and succinate dehydrogenase (SDH) of Xcc. Molecular docking and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis results indicated that Act-X2 steadily bonded to the RNA polymerase, ribosome, malate dehydrogenase, and succinate dehydrogenase to inhibit their activities, thus drastically reducing the expression levels of related genes. Act-X2 showed far more effectiveness than the commercially available pesticide Cu2(OH)3Cl in the prevention and therapy of citrus canker disease. Furthermore, the nontarget toxicity evaluation demonstrated that Act-X2 was not phytotoxic to citrus trees and exhibited minimal toxicity to earthworms in both contact and soil toxic assays. This study suggests that Act-X2 has the potential as an effective and environmentally friendly antibacterial agent.

Control of citrus blue and green molds by Actinomycin X2 and its possible antifungal mechanism.

Citrus blue and green molds caused by Penicillium digitatum, P. italicum, and P. polonicum, are the major postharvest diseases of citrus fruit. In the present study, Actinomycin X2 (Act-X2), a naturally occurring antibiotic produced by Streptomyces species, was found to show excellent antifungal effect against these three pathogens with a minimum inhibitory concentration (MIC) value of 62.5 µg/mL for them all, which was better than the positive control thiophanate-methyl. Act-X2 significantly reduced the percentage of spore germination, and highly inhibited the mycelial growth of P. italicum, P. digitatum, and P. polonicum with EC50 values being 34.34, 13.76, and 37.48 µg/mL, respectively. In addition, Act-X2 greatly decreased the intracellular protein content while increasing the reactive oxygen species (ROS) level and superoxide anion (O2-) content in the mycelia of pathogens. In vivo test indicated that Act-X2 strongly inhibited the infection of navel oranges by these three Penicillium species, with an inhibition percentage of >50% for them all at the concentration of 10 MIC. Transcriptome analysis suggested that Act-X2 might highly influence the ribosomal functions of P. polonicum, which was supported as well by the molecular docking analysis of Act-X2 with some key functional proteins and RNAs of the ribosome. Furthermore, Act-X2 significantly reduced the decay percentage and improved the firmness, color, and sugar-acid ratio of navel oranges spray-inoculated with P. polonicum during the postharvest storage at 4 °C for 60 d.

Changes in the conflicting nongenomic effects of progesterone in rat myometrium during pregnancy.

AIMS: Although the functions of progesterone in the myometrium are well-established, the nongenomic effects of progesterone in pregnant myometrial contractions are still unclear. Therefore, this study aimed to investigate changes in the nongenomic effects of progesterone during pregnancy. MAIN METHODS: Myometrial strips were obtained from non-pregnant, pregnant, and postpartum rats, and the nongenomic effects of progesterone in the myometrium during pregnancy were examined. Additionally, the influence of actinomycin D and cycloheximide and the effects of Org OD-02-0 (a specific membrane progesterone receptor (mPR) agonist) in the myometrium were investigated. Moreover, DNA microarray and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to identify genes involved in progesterone-induced effects in the myometrium. KEY FINDINGS: Progesterone did not cause rhythmic contractions in non-pregnant myometrium but induced rhythmic contractions in pregnant myometrium, with the effects peaking at 20 d + 8 h of pregnancy. However, myometrial contractions decreased after delivery and were restored to non-pregnant levels at 7 d postpartum. Additionally, progesterone stably inhibited high KCl-induced myometrial contractions during pregnancy. Moreover, the nongenomic effects of progesterone were unaffected by actinomycin D or cycloheximide, and Org OD-02-0 effectively mimicked these effects. DNA microarray analysis and qRT-PCR revealed a significant increase in mPRß gene expression during pregnancy. However, mPRα, mPRγ, mPRδ, and mPRε expression levels remained unchanged. SIGNIFICANCE: The stimulatory nongenomic effect of progesterone, which was inducible and mPRß-dependent during pregnancy, may be involved in parturition. The inhibitory effect, which was constitutive and depended on other mPRs, may be involved in pregnancy maintenance.

Gilteritinib in combination with venetoclax, low-dose cytarabine and actinomycin D for relapsed or refractory FLT3-mutated acute myeloid leukaemia.

We have conducted a retrospective, single-centre analysis of 20 patients with relapsed or refractory FLT3-mutated acute myeloid leukaemia (FLT3m AML) who received a salvage quadruplet regimen consisting of gilteritinib, venetoclax, low-dose cytarabine and actinomycin D (G-ACTIVE). G-ACTIVE resulted in a 95% (19/20) overall response rate and 75% (15/20) complete remission and complete remission with an incomplete platelet recovery (CR + CRp) rate. Out of 13 transplant-eligible patients, 11 (86%) proceeded to an allogeneic stem cell transplantation. The median overall survival and relapse-free survival after G-ACTIVE were 32 and 12.9 months respectively. The Day 60 mortality rate was 15%.

Inhibitory Effect on RT-PCR and Restriction Enzyme Activity by Ommochrome and Its Mechanism.

To explore the physiological role and/or pharmacological effects of ommochrome, which is a natural organic pigment widely distributed in Protostomia, we attempted to investigate the influence of ommochrome on RT-PCR and activities of restriction enzymes. It was found that ommin, an ommochrome purified from the diapause eggs of Bombyx mori, inhibited the RT-PCR and restriction enzyme activities. The mechanism of these inhibitory reactions is assumed to be the direct binding of ommochrome to DNA rather than acting against the enzymes because, similarly to actinomycin D, there is a phenoxazine ring in the structure of ommin that is known to be intercalated to DNA. To reveal the ommin/DNA interaction, it was investigated by computational approaches such as molecular docking, molecular dynamics simulation, and free energy calculation. From the computational analyses, it was expected that ommin would bind to DNA with almost the same strength as actinomycin D and intercalate into DNA. This is the first report on the pharmacological effect of ommochrome and its inhibitory mechanism obtained from biochemical and computational analyses.

Review of current literature on gestational trophoblastic neoplasia.

BACKGROUND: Gestational Trophoblastic Neoplasia (GTN) is a disease of the reproductive age group with an incidence rate of <1% among all tumors involving the female reproductive tract. It occurs because of aberrant fertilization. Patients are diagnosed early because of aggravated symptoms during pregnancy. Moreover, patients also bleed from the tumor sites, which leads to early presentation. A cure rate of 100% can be achieved with adequate treatment. MAIN BODY: In this literature review, the authors have brought to attention the risk factors, classification, and various treatment options in GTN patients according to their stratification as per the WHO scoring system. Patients are categorized into low and high risk based on the FIGO scoring system. Patients with low risk are treated with single-agent methotrexate or actinomycin-D. Despite the superiority of actinomycin-D in terms of efficacy, methotrexate remains the first choice of therapy in low-risk patients due to its better toxicity profile. Multi-agent chemotherapy with etoposide, methotrexate, actinomycin-D, cyclophosphamide and vincristine (EMA-CO) leads to complete remission in 93% of high-risk GTN patients. Around 40% of patients with incomplete responses are salvaged with platinum-based multi-agent chemotherapy. Isolated chemo-resistant clones can be salvaged with surgical interventions. CONCLUSION: The mortality in patients with GTN has significantly reduced over time. With adequate multi-disciplinary support, patients with GTN can ultimately be cured and can spend every day healthy reproductive life.

Discovery of a new highly pathogenic toxin involved in insect sepsis.

IMPORTANCE: As a current biocontrol resource, entomopathogenic nematodes and their symbiotic bacterium can produce many toxin factors to trigger insect sepsis, having the potential to promote sustainable pest management. In this study, we found Steinernema feltiae and Xenorhabdus bovienii were highly virulent against the insects. After infective juvenile injection, Galleria mellonella quickly turned black and softened with increasing esterase activity. Simultaneously, X. bovienii attacked hemocytes and released toxic components, resulting in extensive hemolysis and sepsis. Then, we applied high-resolution mass spectrometry-based metabolomics and found multiple substances were upregulated in the host hemolymph. We found extremely hazardous actinomycin D produced via 3-hydroxyanthranilic acid metabolites. Moreover, a combined transcriptomic analysis revealed that gene expression of proteins associated with actinomycin D was upregulated. Our research revealed actinomycin D might be responsible for the infestation activity of X. bovienii, indicating a new direction for exploring the sepsis mechanism and developing novel biotic pesticides.

Comparing biweekly single-dose actinomycin D with multiday methotrexate therapy for low-risk gestational trophoblastic neoplasia (FIGO Score 0-4): study protocol for a prospective, multicentre, randomized trial.

BACKGROUND: Single-agent chemotherapy using methotrexate or actinomycin D is the first-line treatment for patients with low-risk gestational trophoblastic neoplasia. Various methotrexate-based and actinomycin D-based single-agent regimens can be used. However, there is insufficient evidence to determine the superior regimen. To guide doctors in selecting a single-agent chemotherapy regimen for patients with low-risk gestational trophoblastic neoplasia, we will compare two regimens. METHODS: We will conduct a multicentre, randomized, prospective clinical trial. Selected low-risk gestational trophoblastic neoplasia patients (FIGO score 0-4) will be randomized 1:1 to a biweekly single-dose actinomycin D group or a multiday methotrexate therapy group. The actinomycin D group will receive IV pulse actinomycin D (1.25 mg/m2) every 14 days, and the methotrexate group will receive methotrexate (50 mg) intramuscularly on days 1, 3, 5, and 7 (4 doses per cycle) and leucovorin (15 mg) intramuscularly on days 2, 4, 6, and 8. This process will be repeated every 14 days. The primary endpoints will include the complete remission rate by single-agent therapy and the overall complete remission rate. The secondary endpoints will include the duration needed to achieve complete remission after single-agent chemotherapy, number of courses needed to achieve complete remission after single-agent chemotherapy, incidence and severity of adverse effects, effects on menstrual conditions and ovarian function based on the anti-Mullerian hormone level, and patient-reported quality of life. DISCUSSION: Previous clinical trials comparing biweekly single-dose actinomycin D with multiday methotrexate therapy for treating low-risk gestational trophoblastic neoplasia patients failed to meet the expected case number. Through this multicentre study, the complete remission ratio and efficacy difference between biweekly single-dose actinomycin D and multiday methotrexate therapy will be obtained. This study will also provide the basis for formulating a preferred regimen for treating patients with low-risk gestational trophoblastic neoplasia. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04562558, Registered on 13 September 2020 (Protocol version 2020-9-24, version 1.0).

Actinomycins from Soil-Inhabiting Streptomyces as Sources of Antibacterial Pigments for Silk Dyeing.

Actinobacteria produce a broad spectrum of bioactive substances that are used in the pharmaceutical, agricultural, and biotechnology industries. This study investigates the production of bioactive substances in Streptomyces, isolated from soil under five tropical plants, focusing on their potential as natural antibacterial dyes for silk fabrics. Out of 194 isolates, 44 produced pigments on broken rice as a solid substrate culture. Eight antibacterial pigmented isolates from under Magnolia baillonii (TBRC 15924, TBRC 15927, TBRC 15931), Magnolia rajaniana (TBRC 15925, TBRC 15926, TBRC 15928, TBRC 15930), and Cinnamomum parthenoxylon (TBRC 15929) were studied in more detail. TBRC 15927 was the only isolate where all the crude extracts inhibited the growth of the test organisms, Staphylococcus epidermidis TISTR 518 and S. aureus DMST 4745. The bioactive compounds present in TBRC 15927 were identified through LC-MS/MS analysis as belonging to the actinomycin group, actinomycin D (or X1), X2, and X0ß. Also, the ethyl acetate crude extract exhibited non-toxicity at an IC50 value of 0.029 ± 0.008 µg/mL on the mouse fibroblast L-929 assay. From the 16S rRNA gene sequence analysis, TBRC 15927 had 100% identity with Streptomyces gramineus JR-43T. Raw silk dyed with the positive antimicrobial TBRC 15927 extract (8.35 mg/mL) had significant (>99.99%) antibacterial properties. Streptomyces gramineus TBRC 15927 is the first actinomycin-producing strain reported to grow on broken rice and shows promise for antibacterial silk dyeing.

Immunotherapy in the treatment of chemoresistant gestational trophoblastic neoplasia - systematic review with a presentation of the first 4 Brazilian cases.

OBJECTIVE: To evaluate the efficacy of immunotherapy for GTN treatment after methotrexate-resistance or in cases of multiresistant disease, through a systematic review, as well as to present the first 4 Brazilian cases of immunotherapy for GTN treatment. METHODS: Three independent researchers searched five electronic databases (EMBASE, LILACS, Medline, CENTRAL and Web of Science), for relevant articles up to February/2023 (PROSPERO CRD42023401453). The quality assessment was performed using the Newcastle Ottawa scale for case series and case reports. The primary outcome of this study was the occurrence of complete remission. The presentation of the case reports was approved by the Institutional Review Board. RESULTS: Of the 4 cases presented, the first was a low-risk GTN with methotrexate resistance unsuccessfully treated with avelumab, which achieved remission with sequential multiagent chemotherapy. The remaining 3 cases were high-risk multiagent-resistant GTN that were successfully treated with pembrolizumab, among which there were two subsequent gestations, one of them with normal pregnancy and healthy conceptus. Regarding the systematic review, 12 studies were included, only one of them on avelumab, showing a 46.7% complete remission rate. The remaining 11 studies were on pembrolizumab, showing an 86.7% complete remission rate, regardless of tumor histology. Both immunotherapies showed good tolerability, with two healthy pregnancies being recorded: one after avelumb and another after pembrolizumab. CONCLUSION: Immunotherapy showed effectiveness for GTN treatment and may be especially useful in cases of high-risk disease, where pembrolizumab achieves a high therapeutic response, regardless of the histological type, and despite prior chemoresistance to multiple lines of treatment.

Anti-Klebsiella pneumoniae activity of secondary metabolism of Achromobacter from the intestine of Periplaneta americana.

BACKGROUND: Klebsiella pneumoniae is one of the main pathogens of clinical isolation and nosocomial infections, as K. pneumoniae show broad-spectrum resistance to ß-lactam and carbapenem antibiotics. It is emerging clinical need for a safe and effective drug to anti-K. pneumoniae. At present, Achromobacter mainly focused on its degradation of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, assisting insects to decompose, degrade heavy metals and utilize organic matter, but there were few reports on the antibacterial activity of the secondary metabolites of Achromobacter. RESULTS: In this study, a strain WA5-4-31 from the intestinal tract of Periplaneta americana exhibited strong activity against K. Pneumoniae through preliminary screening. The strain was determined to be Achromobacter sp. through the morphological characteristics, genotyping and phylogenetic tree analysis, which is homologous to Achromobacter ruhlandii by 99%, its accession numbe in GenBank at National Center for Biotechnology Information (NCBI) is MN007235, and its deposit number was GDMCC NO.1.2520. Six compounds (Actinomycin D, Actinomycin X2, Collismycin A, Citrinin, Neoechinulin A and Cytochalasin E) were isolated and determined by activity tracking, chemical separation, nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Among them, Actinomycin D, Actinomycin X2, Collismycin A, Citrinin and Cytochalasin E showed a good effect on anti-K. pneumoniae, with MIC values of 16-64 µg/mL. CONCLUSIONS: The study reported Achromobacter, which was from the intestinal tract of Periplaneta americana with the activity against K. Pneumoniae, can produce antibacterial compounds for the first time. It lays the foundation for development of secondary metabolites of insect intestinal microorganisms.

Efficacy analysis of single-agent carboplatin AUC4 2-weekly as second-line therapy for methotrexate-resistant (MTX-R) low risk gestational trophoblastic neoplasia (GTN).

BACKGROUND: Approximately one-third of patients with low-risk Gestational Trophoblastic Neoplasia (WHO 0-6) develop methotrexate-resistance (MTX-R). In the UK, subsequent treatment with either actinomycin-D (ActD) or multi-agent combination chemotherapy has depended on whether the hCG was above or below an hCG threshold. To reduce exposure to combination chemotherapy (CC), over the years the UK service has raised this threshold as well as using single-agent carboplatin AUC6 3-weekly at MTX-R instead of CC. Updated results for carboplatin demonstrate an 86% complete hCG response (hCG CR) but associated with haematological dose-limiting toxicity. METHODS: In 2017, single-agent carboplatin became the national standard second-line treatment following MTX-R at hCG of >3000 IU/L. Carboplatin was changed to two-weekly AUC4 scheduling and continued until normal hCG plus 3 consolidation cycles. For patients failing to respond, CC (Etoposide-Actinomycin-D or EMA-CO) was introduced. RESULTS: 22 evaluable patients with a median hCG at MTX-R of 10,147 IU/L (IQR 5527-19,639) received carboplatin AUC4 2-weekly (median no. of cycles = 6, IQR 2-8). Of these, 36% achieved a hCG CR. All 14 non-CR patients were cured with subsequent CC; 11 and 2 patients with 3rd line and 4th line CC respectively and 1 patient following 5th line CC and hysterectomy. Overall survival remains 100%. CONCLUSION: Carboplatin is not sufficiently active in the second-line treatment of low-risk MTX-resistant GTN. New strategies are required to increase hCG CR and spare more toxic CC regimens.

Pyridine Derivative of Succinic Acid Hydroxylamide Enhances the Cytotoxic Effect of Cisplatin and Actinomycin D.

We studied the possibility of inhibition of histone deacetylases (HDAC) in the nuclear extract of HeLa cells by N1-hydroxy-N4-(pyridin-4-yl)succinamide (compound 1). Compound 1 inhibits HDAC and showed low toxicity for A-172, HepG2, HeLa, MCF-7, and Vero cells. HeLa cells were most sensitive to the compound. Increasing the interval between administration of compound 1 and the chemotherapeutic agent to 8 h led to an increase in the cytotoxic effect of cisplatin (actinomycin D) on HeLa cells. The combination of compound 1 with cisplatin (actinomycin D) reduced the cytotoxic effect of these drugs for non-tumor Vero cells.

Effect of actinomycin D on ovarian reserve in low-risk gestational trophoblastic neoplasia.

OBJECTIVE: This study aimed to explore the single-agent chemotherapy actinomycin D on ovarian reserve by measuring the anti-Mullerian hormone (AMH) levels before, during, and after chemotherapy. METHODS: This study recruited premenopausal women aged 15 to 45 with a newly diagnosed low-risk gestational trophoblastic neoplasia needing actinomycin D. AMH was measured at baseline, during chemotherapy, and 1, 3, and 6 months after the last chemotherapy. The reproductive outcomes were also documented. RESULTS: Of the 42 women recruited, we analyzed 37 (median: 29 years; range 19-45) with a complete dataset. The follow-up was 36 months (range 34-39). Actinomycin D significantly decreased AMH concentrations during treatment, from 2.38±0.92 ng/mL to 1.02±0.96 ng/mL (p<0.05). Partial recovery was seen at 1 month and 3 months after treatment. Full recovery was reached 6 months after treatment among patients younger than 35 years. The only factor correlated with the extent of AMH reduction at 3 months was age (r=0.447, p<0.05). Notably, the number of courses of actinomycin D was not associated with the extent of AMH reduction. A total of 18 (90%) of 20 patients who had a desire to conceive had live births with no adverse pregnancy outcomes. CONCLUSION: Actinomycin D has a transient and minor effect on ovarian function. Age is the only factor that impacts the patient's rate of recovery. Patients will achieve favorable reproductive outcomes after actinomycin D treatment.

Actinomycin-X2-Immobilized Silk Fibroin Film with Enhanced Antimicrobial and Wound Healing Activities.

Actinomycin is a family of chromogenic lactone peptides that differ in their peptide portions of the molecule. An antimicrobial peptide, actinomycin X2 (Ac.X2), was produced through the fermentation of a Streptomyces cyaneofuscatus strain. Immobilization of Ac.X2 onto a prepared silk fibroin (SF) film was done through a carbodiimide reaction. The physical properties of immobilized Ac.X2 (antimicrobial films, AMFs) were analyzed by ATR-FTIR, SEM, AFM, and WCA. The findings from an in vitro study showed that AMFs had a more broad-spectrum antibacterial activity against both S. aureus and E. coli compared with free Ac.X2, which showed no apparent strong effect against E. coli. These AMFs showed a suitable degradation rate, good hemocompatibility, and reduced cytotoxicity in the biocompatibility assay. The results of in vivo bacterially infected wound healing experiments indicated that wound inflammation was prevented by AMFs, which promoted wound repair and improved the wound microenvironment. This study revealed that Ac.X2 transformation is a potential candidate for skin wound healing.

Leptomeningeal disease as a presenting feature of gestational trophoblastic neoplasia: A review and recommendations for management.

OBJECTIVES: Gestational Trophoblastic Neoplasia (GTN) is a rare group of malignant placental-related tumours requiring systemic anti-cancer treatment. Leptomeningeal disease (LMD) related to GTN is not well reported with no consensus in optimal treatment. We offer recommendations for management of these patients. METHODS: We discuss five patients with GTN who presented with features of LMD and were diagnosed with gadolinium-enhanced MRI brain, all of whom received low dose induction etoposide-cisplatin (EP) followed by either EP-etoposide, methotrexate (CNS) and actinomycin-D (EMA) or EMA(CNS)-cyclophosphamide and vincristine (CO). RESULTS: Four out of the five patients additionally received intrathecal methotrexate. Four patients had complete hCG response to first line multi-agent chemotherapy, one patient required second line paclitaxel, cisplatin alternating with paclitaxel, etoposide (TP/TE), where paclitaxel was substituted with nab-paclitaxel due to anaphylaxis, followed by hysterectomy. One of the four initial complete hCG responders relapsed in the lung requiring further systemic treatment with subsequent lobectomy. Patient reported outcomes indicate persistent neurological symptoms are mild and do not affect functionality and quality of life. CONCLUSION: With a follow-up range of 2-6 years, all five patients remain cured demonstrating excellent survival outcomes with the avoidance of whole-brain radiotherapy in all cases.

In vitro and in silico evaluations of actinomycin X2and actinomycin D as potent anti-tuberculosis agents.

Background: Multidrug-resistant tuberculosis (MDR-TB) is one of the world's most devastating contagious diseases and is caused by the MDR-Mycobacterium tuberculosis (MDR-Mtb) bacteria. It is therefore essential to identify novel anti-TB drug candidates and target proteins to treat MDR-TB. Here, in vitro and in silico studies were used to investigate the anti-TB potential of two newly sourced actinomycins, actinomycin-X2 (act-X2) and actinomycin-D (act-D), from the Streptomyces smyrnaeus strain UKAQ_23 (isolated from the Jubail industrial city of Saudi Arabia). Methods: The anti-TB activity of the isolated actinomycins was assessed in vitro using the Mtb H37Ra, Mycobacterium bovis (BCG), and Mtb H37Rv bacterial strains, using the Microplate Alamar Blue Assay (MABA) method. In silico molecular docking studies were conducted using sixteen anti-TB drug target proteins using the AutoDock Vina 1.1.2 tool. The molecular dynamics (MD) simulations for both actinomycins were then performed with the most suitable target proteins, using the GROningen MAchine For Chemical Simulations (GROMACS) simulation software (GROMACS 2020.4), with the Chemistry at HARvard Macromolecular Mechanics 36m (CHARMM36m) forcefield for proteins and the CHARMM General Force Field (CGenFF) for ligands. Results: In vitro results for the Mtb H37Ra, BCG, and Mtb H37Rv strains showed that act-X2 had minimum inhibitory concentration (MIC) values of 1.56 ± 0.0, 1.56 ± 0.0, and 2.64 ± 0.07 µg/mL and act-D had MIC values of 1.56 ± 0.0, 1.56 ± 0.0, and 1.80 ± 0.24 µg/mL respectively. The in silico molecular docking results showed that protein kinase PknB was the preferred target for both actinomycins, while KasA and pantothenate synthetase were the least preferred targets for act-X2and act-D respectively. The molecular dynamics (MD) results demonstrated that act-X2 and act-D remained stable inside the binding region of PknB throughout the simulation period. The MM/GBSA (Molecular Mechanics/Generalized Born Surface Area) binding energy calculations showed that act-X2 was more potent than act-D. Conclusion: In conclusion, our results suggest that both actinomycins X2 and D are highly potent anti-TB drug candidates. We show that act-X2is better able to antagonistically interact with the protein kinase PknB target than act-D, and thus has more potential as a new anti-TB drug candidate.

Synergistic binding of actinomycin D and echinomycin to DNA mismatch sites and their combined anti-tumour effects.

Combination cancer chemotherapy is one of the most useful treatment methods to achieve a synergistic effect and reduce the toxicity of dosing with a single drug. Here, we use a combination of two well-established anticancer DNA intercalators, actinomycin D (ActD) and echinomycin (Echi), to screen their binding capabilities with DNA duplexes containing different mismatches embedded within Watson-Crick base-pairs. We have found that combining ActD and Echi preferentially stabilised thymine-related T:T mismatches. The enhanced stability of the DNA duplex-drug complexes is mainly due to the cooperative binding of the two drugs to the mismatch duplex, with many stacking interactions between the two different drug molecules. Since the repair of thymine-related mismatches is less efficient in mismatch repair (MMR)-deficient cancer cells, we have also demonstrated that the combination of ActD and Echi exhibits enhanced synergistic effects against MMR-deficient HCT116 cells and synergy is maintained in a MMR-related MLH1 gene knockdown in SW620 cells. We further accessed the clinical potential of the two-drug combination approach with a xenograft mouse model of a colorectal MMR-deficient cancer, which has resulted in a significant synergistic anti-tumour effect. The current study provides a novel approach for the development of combination chemotherapy for the treatment of cancers related to DNA-mismatches.