Potent Growth Inhibition Research Articles

Promising growth inhibitory potential of extracted natural silk sericin biopolymer against DEN‐induced liver tumor in male mice

AbstractSilk sericin (SS), a protein biopolymer, is gaining an increasing attention in a variety of biomedical applications. Our objective was to identify the optimal extraction method yielding the highest silk protein content, to assess its chemical elemental composition, to characterize it, and to compare its conformation by X‐ray diffraction and Fourier‐transform infrared versus that of the commercial one. Herein, alkali and high temperature is the perfect approach. This study aimed further to test whether extracted SS could attenuate the adverse hepatotoxic effects induced by diethylnitrosamine (DEN) in mice. Animals were injected intraperitoneally once weekly for four consecutive weeks with physiological saline (0.9% NaCl), DEN (25 mg/kg), SS (1 g/kg) 90 min prior to DEN injection, melatonin (10 mg/kg) followed within 1 h with the administration of SS and 30 min later with DEN. The results confirmed the hepatotoxicity of DEN manifested by an increase in liver enzymes' activity, and pathological changes in the liver tissue. The combined use of SS and/or melatonin with DEN returned most of the parameters to values similar to the controls. Briefly, chemically characterized SS seems a valuable extract for further consideration as anti‐carcinogenic agent. It has the potential to upgrade liver cancer chemotherapeutic agents.

Morin Inhibits Cell Proliferation and Induces Caspase-mediated Apoptotic Cell Death in Glioma C6 Cell Line

Background Glioma is a recurrent form of primary malignant cancer that occurs in the brain and central nervous system. The adults are the major victims of gliomas, and the men are mostly affected. At present, gliomas are treated with surgical resection followed by radiation and the administration of chemodrugs such as temozolomide. The invasive and high recurrence rate of gliomas often reduces the effectiveness of treatment, which leads to poor recovery. Hence, more potent drugs without side effects on long-term treatment need to be discovered to treat gliomas. Morin is one such promising phytochemical that possesses immense pharmacological properties. It is proven to exert anti-inflammatory, antioxidant, anticancer, antibacterial, antidiabetic, and neuroprotective properties. The current research focuses on examining the growth inhibition and apoptosis-inducing potency of morin against glioma C6 cells. Materials and Methods Rat C6 glioma cells were treated with different concentrations of morin and analyzed for cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The intracellular reactive oxygen species (ROS) production and alteration of mitochondrial membrane potential (MMP) by morin in glioma cells were examined with dichlorodihydrofluorescein diacetate (DCHF-DA) and rhodamine 123 staining. The apoptotic induction in glioma cells was analyzed with dual staining and it was confirmed by quantifying the apoptotic protein using the enzyme-linked immunosorbent assay (ELISA) technique. The anti-inflammatory property of morin was assessed by the inflammatory cytokines tumor necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) using the ELISA technique. Results Our MTT results show that morin treatment significantly reduced the cell viability of rat C6 glioma cells. It also significantly increased ROS generation and decreased MMP in rat C6 glioma cells. Morin treatment also effectively increased caspase-3 and caspase-9, the proapoptotic protein Bax, and decreased the antiapoptotic protein Bcl-2. The induction of apoptosis by morin in glioma cells was evident with our acridine orange/ethidium bromide (AO/EtBr) staining results. Morin also decreased the inflammatory cytokine levels in rat C6 glioma cells. Conclusion Our findings have proven that morin significantly induces apoptosis by increasing the levels of apoptotic protein via the generation of ROS. It also effectively reduced inflammatory cytokine levels, thereby exerting anticancer activity against glioma cells. Therefore, morin can be subjected to further research to be designed as a potent anticancer drug to treat gliomas.

Discovery of Novel PROTAC Degraders of p300/CBP as Potential Therapeutics for Hepatocellular Carcinoma.

Adenoviral E1A binding protein 300 kDa (p300) and its closely related paralog CREB binding protein (CBP) are promising therapeutic targets for human cancer. Here, we report the first discovery of novel potent small-molecule PROTAC degraders of p300/CBP against hepatocellular carcinoma (HCC), one of the most common solid tumors. Based upon the clinical p300/CBP bromodomain inhibitor CCS1477, a conformational restriction strategy was used to optimize the linker to generate a series of PROTACs, culminating in the identification of QC-182. This compound effectively induces p300/CBP degradation in the SK-HEP-1 HCC cells in a dose-, time-, and ubiquitin-proteasome system-dependent manner. QC-182 significantly downregulates p300/CBP-associated transcriptome in HCC cells, leading to more potent cell growth inhibition compared to the parental inhibitors and the reported degrader dCBP-1. Notably, QC-182 potently depletes p300/CBP proteins in mouse SK-HEP-1 xenograft tumor tissue. QC-182 is a promising lead compound toward the development of p300/CBP-targeted HCC therapy.

PBRM1 loss is associated with increased sensitivity to MCL1 and CDK9 inhibition in clear cell renal cancer.

MCL1 is a member of the BCL2 family of apoptosis regulators, which play a critical role in promoting cancer survival and drug resistance. We previously described PRT1419, a potent, MCL1 inhibitor with anti-tumor efficacy in various solid and hematologic malignancies. To identify novel biomarkers that predict sensitivity to MCL1 inhibition, we conducted a gene essentiality analysis using gene dependency data generated from CRISPR/Cas9 cell viability screens. We observed that clear cell renal cancer (ccRCC) cell lines with damaging PBRM1 mutations displayed a strong dependency on MCL1. PBRM1 (BAF180), is a chromatin-targeting subunit of mammalian pBAF complexes. PBRM1 is frequently altered in various cancers particularly ccRCC with ~40% of tumors harboring damaging PBRM1 alterations. We observed potent inhibition of tumor growth and induction of apoptosis by PRT1419 in various preclinical models of PBRM1-mutant ccRCC but not PBRM1-WT. Depletion of PBRM1 in PBRM1-WT ccRCC cell lines induced sensitivity to PRT1419. Mechanistically, PBRM1 depletion coincided with increased expression of pro-apoptotic factors, priming cells for caspase-mediated apoptosis following MCL1 inhibition. Increased MCL1 activity has been described as a resistance mechanism to Sunitinib and Everolimus, two approved agents for ccRCC. PRT1419 synergized with both agents to potently inhibit tumor growth in PBRM1-loss ccRCC. PRT2527, a potent CDK9 inhibitor which depletes MCL1, was similarly efficacious in monotherapy and in combination with Sunitinib in PBRM1-loss cells. Taken together, these findings suggest PBRM1 loss is associated with MCL1i sensitivity in ccRCC and provide rationale for the evaluation of PRT1419 and PRT2527 for the treatment for PBRM1-deficient ccRCC.

In silico identification of chikungunya virus replication inhibitor validated using biochemical and cell-based approaches.

Discovering an alternative therapy with a long-lasting effect on symptoms caused by chikungunya virus (CHIKV) infection is prompted by the lack of a vaccine and the absence of safe, effective and non-toxic medications. One potential strategy is synthesizing or identifying small compounds that can specifically target the active site of an essential enzyme and prevent virus replication. Previous site-directed mutagenesis studies have demonstrated the crucial role of the macrodomain, which is a part of non-structural protein 3 (nsP3), in virus replication. Exploiting this fact, the macrodomain can be targeted to discover a natural substance that can inhibit its function and thereby impede virus replication. With this aim, the present study focused on potential CHIKV nsP3 macrodomain (nsP3MD) inhibitors through in silico, in vitro and cell-based methods. Through virtual screening of the natural compound library, nine nsP3MD inhibitors were initially identified. Molecular dynamics (MD) simulations were employed to evaluate these nine compounds based on the stability of their ligand-receptor complexes and energy parameters. Target analysis and ADMET (i.e. absorption, distribution, metabolism, excretion and toxicity) prediction of the selected compounds revealed their drug-like characteristics. Subsequent in vitro investigation allowed us to narrow the selection down to one compound, N-[2-(5-methoxy-1H-indol-3-yl) ethyl]-2-oxo-1,2-dihydroquinoline-4-carboxamide, which exhibited potent inhibition of CHIKV growth. This molecule effectively inhibited CHIKV replication in the stable embryonal rhabdomyosarcoma cell line capable of producing CHIKV. Our findings demonstrate that the selected compound possesses substantial anti-CHIKV nsP3MD activity both in vitro and in vivo. This work provides a promising molecule for further preclinical studies to develop a potential drug against the CHIKV.

Plasmodium falciparum Glutamic Acid-Rich Protein-Independent Polyclonal Antibodies Inhibit Malaria Parasite Growth in Human Erythrocytes.

Plasmodium falciparum glutamic acid-rich protein (PfGARP) is a recently characterized cell surface antigen encoded by Plasmodium falciparum, the causative agent of severe human malaria pathophysiology. Previously, we reported that the human erythrocyte band 3 (SLC4A1) serves as a host receptor for PfGARP. Antibodies against PfGARP did not affect parasite invasion and growth. We surmised that PfGARP may play a role in the rosetting and adhesion of malaria. Another study reported that antibodies targeting PfGARP exhibit potent inhibition of parasite growth. This inhibition occurred without the presence of any immune or complement components, suggesting the activation of an inherent density-dependent regulatory system. Here, we used polyclonal antibodies against PfGARP and a monoclonal antibody mAb7899 to demonstrate that anti-PfGARP polyclonal antibodies, but not mAb7899, exerted potent inhibition of parasite growth in infected erythrocytes independent of PfGARP. These findings suggest that an unknown malaria protein(s) is the target of growth arrest by polyclonal antibodies raised against PfGARP.

Development of Thiazolidinone-Based Pyrazine Derivatives: Synthesis, Molecular Docking Simulation, and Bioevaluation for Anti-Alzheimer and Antibacterial Activities

It is well recognized that heterocyclic compounds have exceptional biomedical applications, which has led scientists to become increasingly interested in their use in this field in the recent past. It is the aim of this study, using a multistep method based on thiazolidinone derivative synthesis, to synthesize thiazolidinone derivatives derived from pyrazine molecules (1–12). As a result of analyzing 1H-NMR, 13C-NMR, and HREI-MS data, the structures of these derivatives were determined. The minimum inhibitory concentration (MIC) of these drugs was also determined alongside the donepezil (IC50 = 10.10 ± 0.10 µM) to determine their potential as anti-Alzheimer agents. Among the screened derivatives, 1 (IC50 = 4.10 ± 0.20 µM), 2 (IC50 = 2.20 ± 0.20 µM), 4 (IC50 = 2.30 ± 0.20 µM), 5 (IC50 = 5.80 ± 0.30 µM), 6 (IC50 = 6.30 ± 0.20 µM), 8 (IC50 = 5.20 ± 0.10 µM), 9 (IC50 = 5.20 ± 0.40 µM), 10 (IC50 = 8.30 ± 0.40 µM), and 11 (IC50 = 8.10 ± 0.70 µM) showed potent activity. In addition, the synthesized moieties were screened against E. coli to determine whether there were any antimicrobial properties. It was found that most of the compounds were more potent inhibitors of bacterial growth in comparison to streptomycin, the reference drug. There have been several molecular docking experiments conducted to gain a deeper understanding of how these compounds interact with the active sites of enzymes to gain a greater understanding of their functional mechanisms.

A novel DDIT3 activator dehydroevodiamine effectively inhibits tumor growth and tumor cell stemness in pancreatic cancer

BackgroundThe existence of pancreatic cancer stem cells (PCSCs) results in limited survival benefits from current treatment options. There is a scarcity of effective agents for treating pancreatic cancer patients. Dehydroevodiamine (DeHE), a quinazoline alkaloid isolated from the traditional Chinese herb Evodiae fructus, exhibited potent inhibition of pancreatic ductal adenocarcinoma (PDAC) cell proliferation and tumor growth both in vitro and in vivo. MethodsThe cytotoxic effect of DeHE on PDAC cells was assessed using CCK-8 and colony formation assays. The antitumor efficacy of DeHE were appraised in human PANC-1 xenograft mouse model. Sphere formation assay and flow cytometry were employed to quantify the tumor stemness. RNA‐Seq analysis, drug affinity responsive target stability assay (DARTS), and RNA interference transfection were conducted to elucidate potential signaling pathways. Western blotting and immunohistochemistry were utilized to assess protein expression levels. ResultsDeHE effectively inhibited PDAC cell proliferation and tumor growth in vitro and in vivo, and exhibited a better safety profile compared to the clinical drug gemcitabine (GEM). DeHE inhibited PCSCs, as evidenced by its suppression of self-renewal capabilities of PCSCs, reduced the proportion of ALDH+ cells and downregulated stemness-associated proteins (Nanog, Sox-2, and Oct-4) both in vitro and in vivo. Furthermore, there is potential involvement of DDIT3 and its downstream DDIT3/TRIB3/AKT/mTOR pathway in the suppression of stemness characteristics within DeHE-treated PDAC cells. Additionally, results from the DARTS assay indicated that DeHE interacts with DDIT3, safeguarding it against degradation mediated by pronase. Notably, the inhibitory capabilities of DeHE on PDAC cell proliferation and tumor stemness were partially restored by siDDIT3 or the AKT activator SC-79. ConclusionIn summary, our study has identified DeHE, a novel antitumor natural product, as an activator of DDIT3 with the ability to suppress the AKT/mTOR pathway. This pathway is intricately linked to tumor cell proliferation and stemness characteristics in PDAC. These findings suggest that DeHE holds potential as a promising candidate for the development of innovative anticancer therapeutics.

Chemopreventive effects of α-tocopherol and its long-chain metabolites α-13'-hydroxy- and α-13'-carboxychromanol in LT97 colon adenoma cells.

Anticancer effects of vitamin E (tocopherols) have been studied extensively. While in vitro and animal studies showed promising results regarding anticancer effects of tocopherols, human intervention studies failed to reproduce these results. In vivo, α-tocopherol (α-TOH) is metabolized to the long-chain metabolites (LCM) 13'-hydroxychromanol (α-13'-OH) and 13'-carboxychromanol (α-13'-COOH), which likely reach the large intestine. The LCM showed antiproliferative effects in different colon cancer cell lines, but the exact mechanism of action remains unclear. To further clarify the chemopreventive action of the LCM, premalignant LT97 colon adenoma cells were treated with α-TOH, α-13'-OH and α-13'-COOH to study their impact on growth, apoptosis, antigenotoxicity, and ROS-scavenging capacity as well as expression of selected genes involved in detoxification and the cell cycle. Growth inhibitory potential was observed for α-13'-OH (IC50: 37.4 μM) and α-13'-COOH (IC50: 5.8 μM) but not for α-TOH in the tested concentrations. Levels of caspase-3 activity and expression of genes regulating the cell cycle and detoxification remained unchanged. However, α-TOH, α-13'-OH and α-13'-COOH exhibited antigenotoxic and partly ROS-scavenging capacity. The results indicate that the LCM exert chemopreventive effects via ROS-scavenging capacity, the protection against DNA damage and the induction of cell death via caspase-independent mechanisms in premalignant colon cells.

Design and synthesis of novel hybrids incorporating thiadiazole or thiazole-naphthalene: Anticancer assessment and molecular docking study

To underscore the significance of thiazole and thiadiazole moieties in advancing cancer treatment and support researchers in drug design, we developed a novel series of 1,3,4-thiadiazole and 1,3-thiazole derivatives. These were synthesized by reacting 2-(naphthalen-1-ylmethylene)-N-phenylhydrazine-1-carbothioamide with hydrazonoyl halides and α-halo-compounds. Spectroscopic data and alternative syntheses confirmed the structures. The growth-inhibitory potential against HepG2-1 liver cancer cells was evaluated using the MTT assay, revealing compounds 5c and 15 with IC50 values of 0.53 ± 0.82 and 0.61 ± 0.72 μM, respectively, demonstrating promising anticancer activity than doxorubicin (IC50 = 0.72 ± 0.49 μM). Given the high attrition rate in drug development, computational approaches were employed to mitigate risks associated with poor pharmacokinetics and safety. Molecular docking analyses of the synthesized compounds illustrated binding interactions at enzymes' sites, consistent with in vitro studies, indicating potential as antitumor agents. In silico investigations affirmed the ADMET profile's favorable oral bioavailability properties for the synthesized compounds. These findings highlight the potential of the investigated ligands as promising candidates for further development as antitumor medicines.

Discovery of Schiff bases as potent antibacterial and antifungal agents

Schiff bases as potent inhibitors of microorganisms growth.

Azo derivatives of monoterpenes as anti-Helicobacter pylori agents: from synthesis to structure-based target investigation.

Helicobacter pylori (Hp) infection affects nearly half of the global population. Current therapeutic options include the administration of a combination of antibiotics and proton pump inhibitors, although antimicrobial resistance rise remains a big concern. Phenolic monoterpenes, e.g., eugenol, vanillin, carvacrol, and thymol, have always attracted researchers for their multifaced biological activities and the possibility to be easily derivatized. Thereby, herein we present the functionalization of such compounds through the conventional aryl diazotization reaction, generating a series of mono- and bis-azo derivatives (1-28). Also, to continue previous studies, we investigated the role of the free phenolic moiety of thymol with eight compounds (29-36). The compounds were tested against four Hp strains including three clinical isolates, finding some potent and selective inhibitors of bacterial growth. Thus, the representative compounds underwent in vitro cytotoxicity evaluation on two normal cell lines and putative target investigation by performing a structure-based approach based on docking calculations on some of the most studied pharmacological targets for Hp, e.g., urease, β-hydroxyacyl-acyl carrier protein dehydratase, glucose 6-phosphate dehydrogenase, and inosine 5'-monophosphate dehydrogenase.

Development of a CD39 nanobody and its enhancement to chimeric antigen receptor T cells efficacy against ovarian cancer in preclinical studies.

Rationale: CD39, a key ectonucleotidase that drives adenosine production, acts as a critical immunosuppressive checkpoint in cancer. Although it has shown promise as a therapeutic target, clinical trials are demonstrating the need for more potent targeting approaches. This need is driving innovation towards the development of novel antibodies and the exploration of strategic combinations with a range of immunotherapies. Methods: An anti-CD39 nanobody was screened and tested for its affinity and binding ability using biolayer interferometry, ELISA and flow cytometry. Blocking ability against soluble and membrane-bound CD39 was measured after CD39 blockade. Internalization was detected using immunofluorescence. The reversal of T-cell function by the anti-CD39 antibody was assessed by CFSE-based T-cell proliferation, CD25 expression and IFN-γ secretion. The in vivo function of tumor growth inhibition was further tested in a mouse model and we also tested the phenotype of immune cells after CD39 antibody administration from tumor tissue, draining lymph nodes and peripheral blood. We inserted the antibody sequence into the chimeric antigen receptor (CAR) construct to induce MSLN CAR-T cells to secret the CD39 antibody, and the efficacy was measured in xenograft models of ovarian cancer. Results: We screened human CD39 antibodies using a VHH library and developed a single-epitope anti-CD39 nanobody, named huCD39 mAb, with high affinity and potent binding and blocking ability. The huCD39 mAb was internalized in a time-dependent manner. The in vitro study revealed that the huCD39 mAb was highly effective in enhancing T-cell proliferation and functionality. In vivo, the huCD39 mAb showed significant anti-tumor efficacy in an immunocompetent mouse model. Flow cytometry analysis demonstrated downregulated CD39 expression in immune cells after antibody administration. We also observed increased CD39 expression in ovarian cancer tissue and in activated CAR T cells. Subsequently, we developed a type of MSLN CAR-T cells secreting huCD39 mAb which showed effective eradication or inhibition in ovarian tumor xenografts. Conclusions: A novel huCD39 mAb with strong blocking ability against human CD39 and potent inhibition of tumor growth has been developed. Furthermore, a modified huCD39 mAb-secreting CAR-T cell has been generated, exhibiting superior efficacy against ovarian cancer. This provides a promising strategy for optimizing immunotherapies in ovarian cancer and potentially other malignancies.

Polysaccharide isolated from Grifola frondosa eliminates myeloid-derived suppressor cells and inhibits tumor growth by enhancing T cells responses.

Myeloid derived suppressor cells (MDSCs) are known to accumulate in cancer patients and tumor-bearing mice, playing a significant role in promoting tumor growth. Depleting MDSCs has emerged as a potential therapeutic strategy for cancer. Here, we demonstrated that a fungal polysaccharide, extracted from Grifola frondosa, can effectively suppress breast tumorigenesis in mice by reducing the accumulation of MDSCs. Treatment with Grifola frondosa polysaccharide (GFI) leads to a substantial decrease in MDSCs in the blood and tumor tissue, and a potent inhibition of tumor growth. GFI treatment significantly reduces the number and proportion of MDSCs in the spleen, although this effect is not observed in the bone marrow. Further analysis reveals that GFI treatment primarily targets PMN-MDSCs, sparing M-MDSCs. Our research also highlights that GFI treatment has the dual effect of restoring and activating CD8+T cells, achieved through the downregulation of TIGIT expression and the upregulation of Granzyme B. Taken together, our findings suggest that GFI treatment effectively eliminates PMN-MDSCs in the spleen, leading to a reduction in MDSC numbers in circulation and tumor tissues, ultimately enhancing the antitumor immune response of CD8+T cells and inhibiting tumor growth. This study introduces a promising therapeutic agent for breast cancer.

A gold cluster fused manganese dioxide nanocube loaded with dihydroartemisinin for effective cancer treatment via amplified oxidative stress.

Chemodynamic therapy, leveraging metabolic processes for reactive oxygen species (ROS) generation, shows promise in cancer eradication. However, its efficacy is hampered by hypoxic conditions, substrate scarcity, and abundant ROS scavengers. In this study, we have devised a cubic manganese oxide nanozyme (BSA-AuNC-MnO2@DHA) to tackle these obstacles. This nanozyme integrates MnO2 with bovine serum albumin (BSA)-coated gold nanoclusters (AuNC), forming BSA-AuNC-MnO2, and further incorporates dihydroartemisinin (DHA) to confer both bioimaging and anticancer capabilities. The BSA-AuNC-MnO2 nanoparticles exhibit a uniform cubic morphology, with an average hydrated particle diameter of 76.4 ± 7.1 nm and a zeta potential of -32.6 mV, indicative of their excellent dispersion and stability. The encapsulation efficiency of DHA within the BSA-AuNC-MnO2@DHA system achieved a remarkable value of 72.45%, attesting to its substantial drug-loading capacity. MnO2 serves a dual function within the nanozyme: it augments oxidative stress while concurrently inhibiting antioxidant defenses. It depletes the antioxidant glutathione (GSH) to release Mn2+, which in turn catalyzes ROS production from intracellular substrates and DHA. The remarkable anticancer efficacy of this tailored approach is evidenced by the potent inhibition of tumor growth observed after a single-dose administration, which underscores the amplification of oxidative stress. Additionally, BSA-AuNC-MnO2@DHA exhibits negligible toxicity to major organs, highlighting its exceptional biocompatibility and safety profile.

Green route synthesis of transition metal doped V2O5 nanoparticles, with emerging biomedical applications

In this proposed work we synthesized the pristine V2O5 nanoparticles and Ag (3.2 % (SV-1), 14.5 %, (SV-5) 23.4 % (SV-9), Cd (5.8 % (CV-1), 23.5 % (CV-5), 35.7 % (CV-9)) and Ru doped (4.9 % (RV-1), 20.7 % (RV-5), 32 % (RV-9)) V2O5 nanoparticles using vigna radiata extract. The nanoparticles were characterized by various techniques like UV-DRS, FT-IR, XRD, FE-SEM and HR-TEM. The antibacterial activities of nanoparticles were studied using bacterial strains such as Staphylococcus aures (S.aureus), Streptococcus pneumoniea (S. pneumoniea), Pseudomonas aeruginosae (P. aeruginosae), Klebsiella pneumoniea (K. pneumoniea) and Escherichia coli (E.coli). Among the nanoparticles the potential bacterium growth inhibition of 99 % for S.aureus was observed for CV-5. The binding efficiency of the nanoparticles with the biomolecule BSA was studied by using UV–visible absorption and emission spectral techniques. It was found that there is a binding interaction between them and the binding constant values are in the range from 104 to 105 M−1. The quenching rate constant (kq) value is bigger than the maximum diffusion constant of biomolecules 2.0 x 1010M−1s−1 suggesting that the interaction is static quenching type. In glucose oxidation studies lower potential with a high current density of 440 mA/cm2 occurred for pristine V2O5 NPs.

(Dimethylamino)methylene hydantoins as building blocks in the synthesis of oxoaplysinopsins and parabanic acids with antifungal activity.

A short, efficient, and stereoselective methodology is described for the synthesis of 5-((dimethylamino)methylene)hydantoins and their conversion into oxoaplysinopsins and parabanic acids. A highly convergent one-pot, two-step reaction between methyl N-arylglycinates, isocyanates, and DMFDMA under microwave irradiation provided the corresponding (dimethylamino)methylene hydantoins as a single E-stereoisomer in high overall yields. The synthesis of (S)-1-(1-phenylethyl) chiral hydantoins, which undergo a stereoselective addition of acetic anhydride, aza-heterocycles, and amines, received special attention. The reaction with indole delivered a series of novel oxoaplysinopsins. Meanwhile, parabanic acids were prepared by a new approach, treating (dimethylamino)methylene hydantoins with mCPBA to generate the oxidative fragmentation of the exocyclic methylene. The antifungal evaluation of the prepared products was carried out on a series of Candida spp., finding potent growth inhibition. According to previous docking studies, this activity is probably due to the inhibitory interaction of the derivatives with the active site of the fungal HMGR enzyme.

Discovery of ASP6918, a KRAS G12C inhibitor: Synthesis and structure–activity relationships of 1-{2,7-diazaspiro[3.5]non-2-yl}prop-2-en-1-one derivatives as covalent inhibitors with good potency and oral activity for the treatment of solid tumors

Although KRAS protein had been classified as an undruggable target, inhibitors of KRAS G12C mutant protein were recently reported to show clinical efficacy in solid tumors. In our previous report, we identified 1-{2,7-diazaspiro[3.5]non-2-yl}prop-2-en-1-one derivative (1) as a KRAS G12C inhibitor that covalently binds to Cys12 of KRAS G12C protein. Compound 1 exhibited potent cellular pERK inhibition and cell growth inhibition against a KRAS G12C mutation-positive cell line and showed an antitumor effect on subcutaneous administration in an NCI-H1373 (KRAS G12C mutation-positive cell line) xenograft mouse model in a dose-dependent manner. In this report, we further optimized the substituents on the quinazoline scaffold based on the structure-based drug design from the co-crystal structure analysis of compound 1 and KRAS G12C to enhance in vitro activity. As a result, ASP6918 was found to exhibit extremely potent in vitro activity and induce dose-dependent tumor regression in an NCI-H1373 xenograft mouse model after oral administration.

Borrelidin-producing and root-colonizing Streptomyces rochei is a potent biopesticide for two soil-borne oomycete-caused plant diseases

Biopesticides are an attractive biotechnological alternative to conventional pesticides for soil-borne plant diseases. A screening strategy with over 100 actinomycetes bacteria isolated from diverse rhizosphere soils uncovered the Streptomyces rochei strain JK1 as a potent inhibitor of oomycete growth. The culture filtrates of the JK1 strain inhibited oomycete growth in plate assays and could suppress two major oomycete-caused plant diseases caused by Pythium myriotylum and Phytophthora sojae. The macrolide secondary metabolite borrelidin was identified using HR-ESI-MS and NMR from growth-inhibitory fractions and inhibited both oomycete growth and plant diseases. The biosynthetic gene clusters in the genome of S. rochei JK1 show the potential to produce other secondary metabolites as well as borrelidin. The JK1 biosynthetic gene clusters are partly conserved among the publicly available S. rochei genomes, whereby each JK1 cluster was shared with at least one of eight other S. rochei strains. The S. rochei JK1 strain, which was isolated from the rhizosphere of soybean plants, colonized soybean roots as well as ginger roots suggesting competence in diverse rhizospheres. The biotechnological application of the strain and fermentation products is emphasized by how the oomycete growth inhibition of the culture filtrate was stable across a range of temperature and pH levels. The genomic, and metabolite data, mechanistic-insights into disease control, and the range of oomycete-caused diseases controlled, all support the S. rochei JK1 strain as an important new bioresource.

Antitumor Activity of the Xanthonoside XGAc in Triple-Negative Breast, Ovarian and Pancreatic Cancer by Inhibiting DNA Repair.

Dysregulation of the DNA damage response may contribute to the sensitization of cancer cells to DNA-targeting agents by impelling cell death. In fact, the inhibition of the DNA repair pathway is considered a promising anticancer therapeutic strategy, particularly in combination with standard-of-care agents. The xanthonoside XGAc was previously described as a potent inhibitor of cancer cell growth. Herein, we explored its antitumor activity against triple-negative breast cancer (TNBC), ovarian cancer and pancreatic ductal adenocarcinoma (PDAC) cells as a single agent and in combination with the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib. We demonstrated that XGAc inhibited the growth of TNBC, ovarian and PDAC cells by inducing cell cycle arrest and apoptosis. XGAc also induced genotoxicity, inhibiting the expression of DNA repair proteins particularly involved in homologous recombination, including BRCA1, BRCA2 and RAD51. Moreover, it displayed potent synergistic effects with olaparib in TNBC, ovarian cancer and PDAC cells. Importantly, this growth inhibitory activity of XGAc was further reinforced in a TNBC spheroid model and in patient-derived ovarian cancer cells. Also, drug-resistant cancer cells showed no cross-resistance to XGAc. Additionally, the ability of XGAc to prevent cancer cell migration was evidenced in TNBC, ovarian cancer and PDAC cells. Altogether, these results highlight the great potential of acetylated xanthonosides such as XGAc as promising anticancer agents against hard-to-treat cancers.