Search Results (12)

Background: KRAS-G12D mutations drive 20–50% of pancreatic/biliary cancers yet remain challenging to target due to GTP-pocket conservation and high cellular GTP levels. While allosteric inhibitors targeting the SWII pocket (e.g., MRTX1133) show promise, limited chemical diversity and paradoxical cellular/enzymatic activity relationships necessitate the exploration of novel scaffolds. This study aims to develop KRAS-G12D inhibitors and PROTACs to offer a selection of new chemical entities through systematic structure–activity optimization and evaluate their therapeutic potential through PROTAC derivatization. Methods: Eleven compounds featuring heterocyclic cores (pyrimidine/pyrido[4,3-d]pyrimidine/5,6,7,8-tetrahydroprodo[3,4-d]pyrimidine) were designed via structure-based drug design. Antiproliferative activity against KRAS-G12D (Panc1), KRAS-G13D (HCT116) and wild-type (A549) cells was assessed using the CCK-8 assay. KRAS-G12D enzymatic inhibition was measured using a GTPase activity assay. Molecular docking simulations (Sybyl 2.0; PDB:7RPZ) elucidated binding modes. Two PROTACs were synthesized from lead compounds by conjugating E3 ligase linkers. All the novel inhibitors and PROTACs were characterized by means of NMR or HRMS. Results: Compound 10c demonstrated selective anti-proliferation in Panc1 cells (IC₅₀ = 1.40 μM) with 4.9-fold greater selectivity over wild-type cells, despite weak enzymatic inhibition (IC₅₀ > 10 μM). Docking revealed critical hydrogen bonds between its protonated 3,8-diazabicyclo[3.2.1]octane moiety and Asp12/Gly60. The enzymatic inhibitor 10k showed potent KRAS-G12D inhibition (IC₅₀ = 0.009 μM) through homopiperazine-mediated interactions with Glu92/His95. Derived PROTACs 26a/b exhibited reduced potency (IC₅₀ = 3–5 μM vs. parental 10k: 2.22 μM), potentially due to impaired membrane permeability. Conclusions: Eleven novel KRAS-G12D inhibitors with a seven-membered ring pharmacophore were synthesized. Compound 10c showed strong anti-proliferative activity, while 10k exhibited potent enzymatic inhibition. Two PROTACs were designed but showed no clear advantage over 10k. This study provides valuable insights for KRAS-targeted drug development. Full article

Various conjugates with rhodamines were prepared by starting with betulinic acid (BA) and platanic acid (PA). The molecules homopiperazine and piperazine, which were identified in earlier research, served as linkers between the rhodamine and the triterpene. The pentacyclic triterpene’s ring A was modified with two acetyloxy groups in order to possibly boost its cytotoxic activity. The SRB assays’ cytotoxicity data showed that conjugates 13–22, derived from betulinic acid, had a significantly higher cytotoxicity. Of these hybrids, derivatives 19 (containing rhodamine B) and 22 (containing rhodamine 101) showed the best values with EC₅₀ = 0.016 and 0.019 μM for A2780 ovarian carcinoma cells. Additionally, based on the ratio of EC₅₀ values, these two compounds demonstrated the strongest selectivity between malignant A2780 cells and non-malignant NIH 3T3 fibroblasts. A375 melanoma cells were used in cell cycle investigations, which showed that the cells were halted in the G1/G0 phase. Annexin V/FITC/PI staining demonstrated that the tumor cells were affected by both necrosis and apoptosis. Full article

The innovative synthesis of 3,8-dibromo-2,9-dinitro-5,6-dihydrodiimidazo [1,2-a:2′,1′-c]pyrazine and 3,9-dibromo-2,10-dinitro-6,7-dihydro-5H-diimidazo [1,2-a:2′,1′-c][1,4]diazepine is described in this study. The tricyclic fused molecular structures are formed by the respective amalgamation of piperazine and homopiperazine with the imidazole ring containing nitro. Compound 1 and 2 possess excellent high-density physical properties (ρ₁ = 2.49 g/cm³, ρ₂ = 2.35 g/cm³) due to the presence of a fused ring structure and Br atom. In addition to their high density, they have high decomposition temperatures (T_d > 290 °C) which means that they have excellent thermal stability and can be used as potential heat-resistant explosives. Low mechanical sensitivities (IS > 40 J, FS > 360 N) are observed. The twinning structure of 2 was resolved by X-ray diffraction. Non-covalent interaction analysis, Hirshfeld surfaces, 2D fingerprint plot, and Electrostatic potential analysis were used to understand the intramolecular interactions in relation to physicochemical properties. The unique structures of this type of compound provide new potential for the evolution of energetic materials. Full article

In this study, the synthesis and biological activities of previously and newly synthesized oleanolic acid derivatives containing seven-membered cyclic amines at the C28 position were described. The obtained compounds were fully characterized via ¹H and ¹³C NMR spectroscopy, and the bioactivity was evaluated by Ellman’s method. Among the tested compounds, 2,3-indolo-oleanolic acid was found to be the most active compound with an IC₅₀ value of 0.78 µM against acetylcholinesterase. These results are significant due to the fact that research on the inhibition of acetylcholinesterase and butyrylcholinesterase enzymes by oleanolic acid, in particular indoloderivatives, is limited. Full article

Triple negative breast cancer (TNBC) is a type of breast cancer associated with early metastasis, poor prognosis, high relapse rates, and mortality. Previously, we demonstrated that SYA013, a selective σ2RL, could inhibit cell proliferation, suppress migration, reduce invasion, and induce mitochondria-mediated apoptosis in MDA-MB-231 cell lines, although we were unable to demonstrate the direct involvement of sigma receptors. This study aimed to determine the anticancer properties and mechanisms of action of SYA014, [4-(4-(4-chlorophenyl)-1,4-diazepan-1-yl)-1-(4-fluorophenyl)butan-1-one oxime], an oxime analogue of SYA013, the contribution of its sigma-2 receptor (σ2R) binding, and its possible synergistic use with cisplatin to improve anticancer properties in two TNBC cell lines, MDA-MB-231 (Caucasian) and MDA-MB-468 (Black). In the present investigation, we have shown that SYA014 displays anticancer properties against cell proliferation, survival, metastasis and apoptosis in the two TNBC cell lines. Furthermore, a mechanistic investigation was conducted to identify the apoptotic pathway by which SYA014 induces cell death in MDA-MB-231 cells. Since SYA014 has a higher binding affinity for σ2R compared to σ1R, we tested the role of σ2R on the antiproliferative property of SYA014 with a σ2R blockade. We also attempted to evaluate the combination effect of SYA014 with cisplatin in TNBC cells. Full article

A series of sixteen A-ring modified (2,3-indolo-, 2-benzylidene) oleanonic acid derivatives, holding some cyclic amines, linear polyamines and benzylaminocarboxamides at C28, has been synthesized and screened for antiviral activity against influenza A/PuertoRico/8/34 (H1N1) and Dengue virus serotypes of DENV-1, -2, -3, -4. It was found that 28-homopiperazine 2 and 3-N-phthalyl 22 amides of oleanonic acid demonstrated high potency with selectivity index SI 27 (IC₅₀ 21 μM) and 42 (IC₅₀ 12 μM). Oleanonic acid aminoethylpiperazine amide 6 and C-azepano-erythrodiol 23 appeared to be the most effective compounds against DENV-1 (IC_50′s 67 and 107 μM) and -2 (IC_50′s 86 and 68 μM correspondingly) serotypes. Full article

The reaction of homopiperazine, C₅N₂H₁₂, with BiBr₃ in strong hydrobromic acid affords a new organic-inorganic hybrid (C₅N₂H₁₄)₂[BiBr₆]Br·H₂O. It crystallizes in the orthorhombic space group, Pbca, with unit cell dimensions of a = 15.0775 (2), b = 15.7569 (2), and c = 20.7881 (4) Å, and eight formula units per unit cell. The crystal structure features slightly distorted octahedral BiBr₆³⁻ and monoatomic Br⁻ anions in the inorganic substructure and C₅N₂H₁₄²⁺ dications and adjacent water molecules in the organic substructure. Various weak interactions that include (N)H···Br, (N)H···O, and (O)H···Br hydrogen bonds ensure the assembling of the structural moieties into a 3D supramolecular structure. (C₅N₂H₁₄)₂[BiBr₆]Br·H₂O shows two emission bands in the photoluminescence spectrum, a rather narrow deep-blue PL at 432 nm, and a broadband red PL centered at 650 nm. Their nature and relations to the crystal structure are discussed in this paper. Full article

Using acid–base assays and simple slow evaporation method at ambient temperature, we were successful in producing a novel salt with the chemical formula (C₅H₁₄N₂)[HgCl₄]·H₂O. According to single-crystal X-ray diffraction data, the crystal packing was regulated by H-bonds and by Coulomb interactions (also called electrostatic interactions) between distinct entities, which formed a 3D network. The 2D fingerprint plots and the Hirshfeld surface were utilized to examine the effect of intermolecular interactions. FTIR spectroscopy, PL spectroscopy, thermal analysis, and electrical conductivity experiments were also carried out, and the antioxidant activity was tested. Full article

Pentacyclic triterpenoic acids (betulinic, oleanolic, ursolic, and platanic acid) were selected and subjected to acetylation followed by the formation of amides derived from either piperazine or homopiperazine. These amides were coupled with either rhodamine B or rhodamine 101. All of these compounds were screened for their cytotoxic activity in SRB assays. As a result, the cytotoxicity of the parent acids was low but increased slightly upon their acetylation while a significant increase in cytotoxicity was observed for piperazinyl and homopiperazinyl amides. A tremendous improvement in cytotoxicity was observed; however, for the rhodamine B and rhodamine 101 conjugates, and compound 27, an ursolic acid derived homopiperazinyl amide holding a rhodamine 101 residue showed an EC₅₀ = 0.05 µM for A2780 ovarian cancer cells while being less cytotoxic for non-malignant fibroblasts. To date, the rhodamine 101 derivatives presented here are the first examples of triterpene derivatives holding a rhodamine residue different from rhodamine B. Full article

Exploiting a template effect of 1,4-diazacycloheptane (also known as homopiperazine, Hpipe), four new hybrid iodides, (HpipeH₂)₂Bi₂I₁₀·2H₂O, (HpipeH₂)I(I₃), (HpipeH₂)₃I₆·H₂O, and (HpipeH₂)₃(H₃O)I₇, were prepared and their crystal structures were solved using single crystal X-ray diffraction data. All four solid-state crystal structures feature the HpipeH₂²⁺ cation alternating with Bi₂I₁₀^4–, I₃^–, or I^– anions and solvent water or H₃O⁺ cation. HpipeH₂²⁺ assembles anionic and neutral building blocks into polymer structures by forming four strong (N)H···I and (N)H···O hydrogen bonds per cation, with the H···I distances ranging from 2.44 to 2.93 Å and H···O distances of 1.88–1.89 Å. These hydrogen bonds strongly affect the properties of compounds; in particular, in the case of (HpipeH₂)₂Bi₂I₁₀·2H₂O, they ensure narrowing of the band gap down to 1.8 eV and provide high thermal stability up to 240 °C, remarkable for a hydrated molecular solid. Full article

Aluminum (Al) toxicity is a major constraint to plant growth and crop yield in acid soils. Tomato cultivars are especially susceptible to excessive Al³⁺ accumulated in the root zone. In this study, tomato plants were grown in a hydroponic culture system supplemented with 50 µM AlK(SO₄)₂. Seeds harvested from Al-treated plants contained a significantly higher Al content than those grown in the control hydroponic solution. In this study, these Al-enriched tomato seeds (harvested from Al-treated tomato plants) were germinated in 50 µM AlK(SO₄)₂ solution in a homopiperazine-1,4-bis(2-ethanesulfonic acid) buffer (pH 4.0), and the control solution which contained the buffer only. Proteomes of radicles were analyzed quantitatively by mass spectrometry employing isobaric tags for relative and absolute quantitation (iTRAQ^®). The proteins identified were assigned to molecular functional groups and cellular metabolic pathways using MapMan. Among the proteins whose abundance levels changed significantly were: a number of transcription factors; proteins regulating gene silencing and programmed cell death; proteins in primary and secondary signaling pathways, including phytohormone signaling and proteins for enhancing tolerance to abiotic and biotic stress. Among the metabolic pathways, enzymes in glycolysis and fermentation and sucrolytic pathways were repressed. Secondary metabolic pathways including the mevalonate pathway and lignin biosynthesis were induced. Biological reactions in mitochondria seem to be induced due to an increase in the abundance level of mitochondrial ribosomes and enzymes in the TCA cycle, electron transport chains and ATP synthesis. Full article