Search Results (144)

Retinoid X receptor α (RXRα) plays a vital role in multiple biological and pathological processes and represents a promising therapeutic target for anti-tumor drug design. Inspired by the marine-derived RXRα antagonist meroterpenthiazole A, 21 undescribed benzothiazole derivatives were designed and synthesized. The inhibitory effects of 21 derivatives on RXRα transactivation and their anti-tumor activities against MDA-MB-231 cells were evaluated. Compounds 4a–4h, 6a–6b, 7c–7f, and 7h–7i inhibited 9-cis-retinoic acid-induced RXRα transactivation, while compounds 3b, 4f–4h, 7a, 7c, 7f, and 7h–7i exhibited inhibitory effects on the proliferation of MDA-MB-231 cells. Meanwhile, the structure–activity relationships governing both the RXRα antagonist effects and the anti-proliferative activities against MDA-MB-231 cells were discussed. Compound 7i exhibited the most potent inhibitory effects on the proliferation of MDA-MB-231 cells with an IC₅₀ value of 16.5 μM. Further mechanism studies revealed that compound 7i induced G2/M phase arrest in MDA-MB-231 cells, accompanied by dose-dependent downregulation of Cyclin B1 and CDK1 protein expression. However, these effects were abolished in RXRα-knockout MDA-MB-231 cells, indicating that the anti-proliferative and cell cycle arrest activities of 7i were RXRα-dependent. Cellular Thermal Shift Assay (CETSA) and molecular docking studies further confirmed that 7i directly bound to RXRα, thereby mediating its anti-cancer efficacy. Full article

Effective intracellular delivery for ovarian cancer therapy remains a significant challenge. We present chrysin-loaded p(MMA-co-DMAEMA)-b-(OEGMA-co-DMA), PMOD-Chr, a nanoparticle platform precisely engineered via RAFT polymerization for advanced therapeutic delivery. This multi-functional platform features a hydrophobic p(MMA) core encapsulating chrysin (Chr), a pH-responsive p(DMAEMA) segment for endosomal escape, and a hydrophilic OEGMA (Oligo(ethylene glycol) methyl ether methacrylate) shell functionalized for enhanced cellular affinity and systemic stability. The combination of OEGMA and DMA (Dopamine methacrylamide) block facilitates passive targeting of ovarian cancer cells, enhancing internalization. Nanoparticles prepared via the nanoprecipitation method exhibited ~220 nm, demonstrating effective size modulation along with high homogeneity and spherical morphology. In A2780 and OVCAR3 ovarian cancer cells, PMOD-Chr demonstrated significantly enhanced cytotoxicity, substantially lowering the effective IC₅₀ dose of Chr. Mechanistically, PMOD-Chr induced a potent G2/M cell cycle arrest, driven by the upregulation of the CDK1/Cyclin B1 complex. Furthermore, the formulation potently triggered programmed cell death by concurrently activating both the intrinsic apoptotic pathway, evidenced by the modulation of Bax, Bcl2, and caspase 9, and the extrinsic pathway involving caspase 8. These findings emphasize that precision engineering via RAFT polymerization enables the creation of sophisticated, multi-stage nanomedicines that effectively overcome key delivery barriers, offering a highly promising targeted strategy for ovarian cancer. Full article

Marine tunicates are a very attractive and abundant source of secondary metabolites with chemical diversity and biological activity. Fractionation and purification of the organic extract of the Red Sea tunicate Didemnum species resulted in the isolation and identification of three new compounds, didemnosides A and B (1 and 2) and 1,1′,3,3′-bisuracil (3), together with thymidine (4), 2′-deoxyuridine (5), homarine (6), and acetamide (7). Planar structures of the compounds were explained through analyses of their 1D (¹H and ¹³C) and 2D (¹H–¹H COSY, HSQC, and HMBC) NMR spectra and high-resolution mass spectral determinations. Compound 1 exhibited the highest growth inhibition toward the MCF-7 cancer cell line with IC₅₀ values of 0.597 μM, while other compounds were inactive (≥50 μM) against this cell line. On the other hand, compounds 1, 2, and 4–7 moderately inhibited SW-1222 and PC-3 cells with IC₅₀ values ranging between 5.25 and 9.36 μM. Molecular docking analyses of the top three active compounds on each tested cell line exposed stable interactions into the active pockets of estrogen receptor alpha (ESR1), human topoisomerase II alpha (TOP2A), and cyclin-dependent kinase 5 (CDK5) which are contemplated as essential targets in cancer treatments. Thus, compound 1 represents a scaffold for the development of more effective anticancer drugs. Full article

As the most aggressive primary brain tumor, glioblastoma (GBM) is considered incurable due to its molecular heterogeneity and therapy resistance. Identifying key regulatory factors in GBM is critical for developing effective therapeutic strategies. Based on the analysis of TCGA data, we confirmed a robust co-expression and correlation of OLIG1 and OLIG2 in human GBM. However, their roles in the astrocytic GBM subtype remain unclear. In this study, we first establish an astrocytic-featured GBM mouse model by introducing PiggyBac-driven hEGFRvIII plasmids and demonstrate that both OLIG1 and OLIG2 are highly expressed within this context. Next, using CRISPR/Cas9 technology to knockout Olig1/2, we found that astrocyte differentiation markers such as GFAP, SOX9, and HOPX were preserved, but tumor cell proliferation was significantly diminished. Mechanistically, CUT&Tag-seq revealed that OLIG1/2 directly binds to the promoter region of various cyclins (Cdk4, Ccne2, Ccnd3, and Ccnd1), where an enrichment of the active histone marker H3K4me3 was observed, indicating transcriptional activation of the genes. Notably, Olig1/2 knockout did not suppress tumor initiation or migration, suggesting that their primary role is to amplify proliferation rather than to drive tumorigenesis. This study defines Olig1 and Olig2 as master regulators of GBM proliferation through various cyclins, thereby offering a novel therapeutic target. Full article

The control of cyclin-dependent kinase 1 (CDK1) kinase activity is crucial for cell cycle progression. Cell division cycle 6 (CDC6) inhibits this activity in embryonic mitoses, and thus regulates the timing of cell division progression. The meiotic cell cycle differs greatly from the mitotic one. Metaphase II (MII)-arrested oocytes remain in prolonged M-phase state due to the high activity of CDK1 in the presence of CytoStatic Factor (CSF). The role of CDC6 in the control of CDK1 during MII and oocyte activation remains unknown. Here, we studied the role of CDC6/CDK1 interactions in Xenopus laevis cell-free extracts arrested in MII (CSF extract) and upon calcium activation leading to meiotic-to-mitotic transition. The CSF extract allows analysis of biochemical processes based on immunodepletion of selected proteins and facilitates manipulations using addition of recombinant proteins. We show by glutathione S-transferase (GST)-CDC6 pull-down that CDC6 associates with CDK1 in CSF extract and by histone H1 kinase assay that it downregulates CDK1 activity. Thus, CDC6-dependent inhibition of CDK1 is involved in the homeostasis of the MII-arrest. Upon CSF extract activation with calcium exogenous GST-CDC6 provokes accelerated transition from MII to interphase, while the depletion of endogenous CDC6 results in a slower transition to interphase. We demonstrate this by following both the phosphorylation state of CDK1 substrate cell division cycle 27 (CDC27) and histone H1 kinase assay. Importantly, increasing doses of GST-CDC6 proportionally accelerate CDK1 inactivation showing that CDC6 controls the dynamics of MII to interphase transition in a dose-dependent manner. Thus, CDC6 is a CDK1 silencer acting upon both the MII arrest and CSF extract activation by assuring the physiological activity of CDK1 during this meiotic arrest and correct timely inactivation of this kinase during the second process. Thus, we show that CDC6 controls CDK1 not only during mitotic divisions, but also in MII-arrest and the meiotic-to-mitotic transition in Xenopus laevis cell-free extracts. This study aims to bridge that gap by investigating CDC6 function using a biochemically controlled system. Full article

Lung cancer, particularly non-small-cell lung cancer (NSCLC), remains a leading cause of cancer-related mortality, with cisplatin-based chemotherapy being a standard treatment. However, the development of chemoresistance significantly limits its efficacy, necessitating alternative therapeutic approaches. Here, we demonstrate the anticancer effects of the extracts of Allium pseudojaponicum Makino (APE), a salt-tolerant plant, in cisplatin-resistant NSCLC. Metabolite profiling using UPLC-Q-TOF-MS^E identified 13 major compounds, predominantly alkaloids (71.65%) and flavonoids (8.81%), with key bioactive constituents such as lycorine (29.81%), tazettine (17.22%), and tricetin (8.19%). APE significantly inhibited cell viability in A549 and H460 cells, reducing viability to 38.6% (A549-Ctr), 37.2% (A549-CR), 28.4% (H460-Ctr), and 30.4% (H460-CR) at 40 µg/mL after 48 h. APE also suppressed colony formation by over 90% in both 2D and soft agar assays, while showing no cytotoxicity in normal human keratinocytes up to 80 µg/mL. Flow cytometry analysis revealed APE-induced G1 phase arrest, with the G1 population increasing from 50.4% to 56.6% (A549-Ctr) and 47.5% to 58.4% (A549-CR), accompanied by reduced S phase populations. This effect was associated with the downregulation of G1/S transition regulators, including cyclin D1, CDK4, cyclin E, and CDK2. Furthermore, proteomic analysis identified STAT3 signaling as a major target of APE; APE decreased phosphorylated STAT3 and c-Myc expression, and STAT3 knockdown phenocopied the effects of APE. These findings highlight the potential of APE as a natural product-based therapeutic strategy for overcoming cisplatin resistance in NSCLC. Full article

This study aimed to assess the recovery capability of Chang liver cells (CCL-13) following simulated microgravity (SMG) induction. CCL-13 cells were cultured under SMG conditions for 72 h, and control group cells were cultured under 1G conditions for an identical duration. Cells from the SMG and control groups were further cultured under 1G conditions and assessed after 24 h and 72 h intervals in the gravity recovery experiment. The WST1 results indicated that CCL-13 proliferation was more evident in the control group than in the SMG group after both the 24 h and 72 h intervals. The control group had a lower percentage of CCL-13 cells in the G0/G1 phase compared with the SMG group at both time points, and it exhibited a higher total percentage of cells in the S and G2/M phases. The control group exhibited elevated levels of cell-cycle-related proteins, including cyclin A, cyclin D, and cdk6, compared with the SMG group. The flow cytometry results revealed that the apoptotic rate in the control group was significantly lower than that in the SMG group at both the 24 h and 72 h time points. However, the apoptotic percentage in the SMG group at the 72-h mark was significantly lower than that at the 24-h mark. SMG reduces the viability and proliferation ability of CCL-13 cells. After a period of recovery and adaptation to normal gravity conditions (1G), the CCL-13 cells in the SMG group showed better signs of recovery after 72 h than after 24 h. Full article

Cancer remains one of the leading causes of death globally, driving the need for effective therapies. Targeting cyclin-dependent kinase 2 (CDK2), a critical cell cycle regulator, is a promising approach for cancer treatment. This study developed a new group of 5-methylisatin derivatives with strong binding potential to CDK2. By combining the isatin core with various benzoylhydrazide substituents, the design process was guided by molecular docking, dynamic simulations, and ADMET analysis. Thirty-one derivatives were modelled, and a subset was synthesised and characterised for their physicochemical and spectroscopic properties. The analysis suggested that substitutions at R2 and R3 positions improved binding affinity, while modifications at R4 were less favourable. Hydrogen bonds with GLU81 and LEU83, along with hydrophobic interactions, were key to stabilising the complexes. A comparison with a reference molecule (RM) 3-((2,6-Dichlorobenzylidene)hydrazono)indolin-2-one, showing inhibitory activity similar to doxorubicin, revealed several advantages for the new derivatives. The multidimensional comparative analysis highlighted significant improvements in active site affinity, conformational stability, and fit. ADMET analysis confirmed comparable performance in most areas, with superior bioavailability observed in derivatives 1, 2a, 2b, 3h, 3b, and 3e. These results suggest that 5-methylisatin derivatives could be promising CDK2 inhibitors. Full article

Mitoregulin (MTLN) is a 56-amino-acid mitochondrial microprotein known to modulate mitochondrial energetics. MTLN gene expression is elevated broadly across most cancers and has been proposed as a prognostic biomarker for non-small cell lung cancer (NSCLC). In addition, lower MTLN expression in lung adenocarcinoma (LUAD) correlates with significantly improved patient survival. In our studies, we have found that MTLN silencing in A549 NSCLC cells slowed proliferation and, in accordance with this, we observed the following: (1) increased proportion of cells in the G1 phase of cell cycle; (2) protein changes consistent with G1 arrest (e.g., reduced levels and/or reduced phosphorylation of ERK, MYC, CDK2, and RB, and elevated p27^Kip1); (3) reduction in clonogenic cell survival and; (4) lower steady-state cytosolic and mitochondrial H₂O₂ levels as indicated by use of the roGFP2-Orp1 redox sensor. Conflicting with G1 arrest, we observed a boost in cyclin D1 abundance. We also tested MTLN silencing in combination with buthionine sulfoximine (BSO) and auranofin (AF), drugs that inhibit GSH synthesis and thioredoxin reductase, respectively, to elevate the reactive oxygen species (ROS) amount to a toxic range. Interestingly, clonogenic survival after drug treatment was greater for MTLN-silenced cultures versus the control cultures. Lower H₂O₂ output and reduced vulnerability to ROS damage due to G1 status may have jointly contributed to the partial BSO + AF resistance. Overall, our results provide evidence that MTLN fosters H₂O₂ signaling to propel G1/S transition and suggest MTLN silencing as a therapeutic strategy to limit NSCLC growth. Full article

Cyclin-dependent kinase 6 (CDK6) has been identified as a potential drug target in various types of cancers. In our current study, multiple independent molecular dynamics simulations of four separate replicates and computations of binding free energies are carried out to decipher the binding mechanisms of three inhibitors, LQQ, 6ZV, and 0RS, to CDK6. The dynamic analyses indicate that the presence of inhibitors influences conformational alterations, motion modes, and the internal dynamics of CDK6. Binding free energies computed using the molecular mechanics generalized Born surface area (MM-GBSA) approach with four GB models demonstrate that hydrophobic interactions play essential roles in inhibitor–CDK6 binding. The computations of residue-based free energy decomposition verify that the side chains of residues I19, K29, M54, P55, F98, H100, and L152 significantly contribute to inhibitor–CDK6 binding, revealing the critical interaction sites of inhibitors for CDK6. The information revealed in our current study can provide theoretical aids for development of potent inhibitors targeting the CDK family. Full article

Background/Objectives: Cleft palate is a birth defect associated with environmental and genetic factors. Disturbance of microRNAs (miRNAs) and exposure to medicinal agents during pregnancy can cause cleft palate. Although an association between medicine-induced cleft palate and miRNAs has been suggested, it remains to be fully elucidated. This study aimed to clarify the molecular mechanism underlying mycophenolate mofetil (MPM)-induced inhibition of cell proliferation and miRNA expression in human embryonic palatal mesenchymal (HEPM) cells. Methods: Cell viability, apoptosis, and cell cycle-related markers were evaluated 48 h after MPM treatment. In addition, miRNA levels and expression of their downstream genes were measured, and a rescue experiment was performed using miR-4680-3p and/or let-7c-5p inhibitors. Results: MPM dose-dependently reduced HEPM cell viability. Additionally, MPM treatment suppressed cyclin-D1, cyclin E1, cyclin-dependent kinase (CDK)-2, and CDK6 expression in HEPM cells. Furthermore, MPM upregulated miR-4680-3p and let-7c-5p expression and downregulated the downstream genes of each miRNA. Moreover, miR-4680-3p and/or let-7c-5p inhibitors alleviated MPM-induced inhibition of cell proliferation. Conclusions: These results suggest that MPM-induced cleft palate is associated with miR-4680-3p and let-7c-5p expression in HEPM cells. Full article

In the Nicotiana tabacum flower development study, we identified SCI1 (Stigma/style Cell-cycle Inhibitor 1), a regulator of cell proliferation. SCI1 interacts with NtCDKG;2 (N. tabacum Cyclin-Dependent Kinase G;2), a homolog of human CDK11, which is responsible for RanGTP-dependent microtubule stabilization, regulating spindle assembly rate. In a Y2H screening of a cDNA library using NtCDKG;2 as bait, a RanBP1 (Ran-Binding Protein 1) was revealed as its interaction partner. RanBP1 is an essential regulatory protein of the RanGTPase system, contributing to the formation of the Ran gradient, which modulates different important cellular processes. RanBP1 is crucial in the nuclear import/export machinery during interphase and spindle checkpoint formation during cell division. These processes are well studied in animals, but very little is known about them in plants. We confirmed NtCDKG;2 and NtRanBP1 interaction by pairwise Y2H and characterized the localization of both proteins during plant cell division. We demonstrated the presence of NtRanBP1 in the cytoplasm during interphase and its nuclear arrest at mitosis onset. Meanwhile, we showed that NtCDKG;2 is localized in the mitotic spindle during cell division, indicating an analogous function to the human CDK11. We propose that the phosphorylation of the nuclear export signal at RanBP1 by NtCDKG;2 may be responsible for the reported nuclear arrest. Full article

Meriolins (3-(pyrimidin-4-yl)-7-azaindoles) are synthetic hybrids of the naturally occurring alkaloids variolin and meridianin and display a strong cytotoxic potential. We have recently shown that the novel derivative meriolin 16 is highly cytotoxic in several lymphoma and leukemia cell lines as well as in primary patient-derived lymphoma and leukemia cells and predominantly targets cyclin-dependent kinases (CDKs). Here, we efficiently synthesized nine novel 2-aminopyridyl meriolin congeners (3a–3i), i.e., pyrimeriolins, using a one-pot Masuda borylation-Suzuki coupling (MBSC) sequence, with eight of them bearing lipophilic alkoxy substituents of varying length, to systematically determine the influence of the alkoxy sidechain length on the biological activity. All the synthesized derivatives displayed a pronounced cytotoxic potential, with six compounds showing IC₅₀ values in the nanomolar range. Derivatives 3b–3f strongly induced apoptosis and activated caspases with rapid kinetics within 3–4 h in Jurkat leukemia and Ramos lymphoma cells. The induction of apoptosis by the most potent derivative 3e was mediated by the intrinsic mitochondrial death pathway, as it was blocked in caspase-9 deficient and Apaf-1 knockdown Jurkat cells. However, as recently shown for meriolin 16, derivative 3e was able to induce apoptosis in the Jurkat cells overexpressing the antiapoptotic protein Bcl-2. Since tumor cells often inactivate the intrinsic mitochondrial apoptosis pathway (e.g., by overexpression of Bcl-2), these meriolin congeners represent promising therapeutic agents for overcoming therapeutic resistance. Full article

Background/Objectives: In connection with previous work on V-shaped polycyclic thiazolo[5,4-f]quinazolin-9-one and [5,4-f]quinazoline derivatives that can modulate the activity of various kinases, the synthesis of straight thiazole-fused [4,5-g] or [5,4-g]quinazolin-8-ones and quinazoline derivatives hitherto undescribed was envisioned. Methods: An innovative protocol allowed to obtain the target structures. The synthesis of inverted thiazolo[4,5-h] and [5,4-h]quinazolin-8-one derivatives was also explored with the aim of comparing biological results. The compounds obtained were tested against a representative panel of eight mammalian protein kinases of human origin: CDK9/CyclinT, Haspin, Pim-1, GSK-3β, CK-1ε, JAK3, CLK1 and DYRK1A. Results and Conclusions: The results obtained show that the novel linear thiazoloquinazolines are not kinase inhibitors. The cytotoxicity of these newly synthesized compounds was assessed against seven representative tumor cell lines (human cancers: Huh7-D12, Caco-2, HCT-116, MCF-7, MDA-MB-231, MDA-MB-468 and PC-3). The majority of these novel molecules proved capable of inhibiting the growth of the tested cells. The 7-Benzyl-8-oxo-7,8-dihydrothiazolo[5,4-g]quinazolinones 5b and 6b are the most potent, with IC₅₀ values in the micromolar range. None of these compounds showed toxicity against normal cells. A larger program of investigations will be launched to investigate the real potential interest of such compounds in anticancer applications. Full article

Background/Objectives: Lung cancer is one of the deadliest cancers, and drug resistance complicates its treatment. Mahanine (MH), an alkaloid from Murraya koenigii has been known for its anti-cancer properties. However, its effectiveness and mechanisms in treating non-small cell lung cancer (NSCLC) remain largely unexplored. The present study aimed to investigate MH’s effect on drug-sensitive and drug-resistant NSCLC and its potential mechanism of action. Methods: We isolated MH from M. koenigii leaves and the purity (99%) was confirmed by HPLC, LC-MS and NMR. The antiproliferative activity of MH was determined using MTT and colony formation assays against drug-sensitive (A549 and H1299) and Taxol-resistant lung cancer cells (A549-TR). Western blot analysis was performed to determine MH’s effects on various molecular targets. Anti-tumor activity of MH was determined against lung tumors developed in female NOD Scid mice injected with A549-Fluc bioluminescent cells (1.5 × 10⁶) intrathoracically. Results: MH dose-dependently reduced the proliferation of all lung cancer cells (A549, H1299 and A549-TR), with IC50 values of 7.5, 5, and 10 µM, respectively. Mechanistically, MH arrested cell growth in the G0/G1 and G2/M phases of the cell cycle by inhibiting cyclin-dependent kinase 4/6 (CDK4/6) and cell division control 2 (CDC2) and induced apoptosis through the downregulation of B-cell leukemia/lymphoma 2 (BCL2) and B-cell lymphoma-extra large (BCL-XL). The apoptotic induction capacity of MH can also be attributed to its ability to inhibit pro-oncogenic markers, including mesenchymal–epithelial transition factor receptor (MET), phosphorylated protein kinase B (p-AKT), phosphorylated mammalian target of rapamycin (p-mTOR), survivin, rat sarcoma viral oncogene (RAS), myelocytomatosis oncogene (cMYC), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) levels. In vivo, MH (25 mg/kg b. wt.) significantly (p < 0.001) inhibited the growth of A549 lung cancer orthotopic xenografts in NOD Scid mice by 70%. Conclusions: Our study provides new mechanistic insights into MH’s therapeutic potential against NSCLC. Full article