Induced Cell Cycle Arrest Research Articles

Coptisine-mediated downregulation of E2F7 induces G2/M phase arrest in hepatocellular carcinoma cells through inhibition of E2F4/NFYA/NFYB transcription factors

Coptisine (COP) has been shown to exhibit a wide range of anticancer properties, including in hepatocellular carcinoma (HCC). Nevertheless, the precise mechanism of COP in the treatment of HCC remains elusive. This study aims to investigate the potential mechanism of action of COP against HCC. By evaluating the anti-HCC activity of COP in different HCC cells lines and in xenografted nude mice, it was found that COP inhibited HCC in vitro and in vivo. Through RNA-Seq analysis, E2F7 was identified as a potential target of COP against HCC, as well as the cell cycle as a possible pathway. The overexpression of E2F7 and the inhibition of CHK1 demonstrated that COP inhibits the activity of HCC and induces G2/M phase arrest of HCC cells by down-regulating E2F7 and influencing the CHK1/CDC25A pathway. Finally, the promoter fragmentation experiments and chromatin immunoprecipitation revealed that COP down-regulated E2F7 by inhibiting the E2F4/NFYA/NFYB transcription factors. In conclusion, our study demonstrated that COP downregulates E2F7 by affecting key transcription factors, thereby inducing cell cycle arrest and inhibits HCC cell growth. This provides further evidence of the efficacy of COP in the treatment of tumors.

Senescence-Induced Atherosclerosis: The Potency of Senolytic Therapy

The aging process is an inevitable occurrence that involves physiological changes at the cellular level. The presence of intrinsic and extrinsic stressors can cause cellular damage, leading to senescence and premature aging. Senescent cells undergo activation of the p53/p21 and p16INK4a pathways, induce cell cycle arrest, increased expression of senescence-associated beta-galactosidase (SA-β-Gal), and secretion of SASP (senescence-associated secretory phenotype), leading to "inflamm-aging" or chronic inflammation associated with senescence. These premature aging and “inflamm-aging” accelerates the occurrence of age-related diseases, one of which is atherosclerosis. The relationship between premature aging, senescence, and atherosclerosis has been a focus of research on pathogenesis, prevention, and therapy. Recent research has emphasized the crucial role of senolytics, compounds or agents capable of eliminating senescent cells, in inhibiting the progression of atherosclerosis and slowing down premature aging. Obtaining a more comprehensive understanding of the processes and effectiveness of senolytics in premature aging and atherosclerosis should facilitate the development of more potent medicines to mitigate side effects in the management of cardiovascular disease and extend longevity.

Novel 9-Methylanthracene Derivatives as p53 Activators for the Treatment of Glioblastoma Multiforme.

Glioblastoma multiforme, a highly aggressive and lethal brain tumor, is a substantial clinical challenge and a focus of increasing concern globally. Hematological toxicity and drug resistance of first-line drugs underscore the necessity for new anti-glioma drug development. Here, 43 anthracenyl skeleton compounds as p53 activator XI-011 analogs were designed, synthesized, and evaluated for their cytotoxic effects. Five compounds (13d, 13e, 14a, 14b, and 14n) exhibited good anti-glioma activity against U87 cells, with IC50 values lower than 2 μM. Notably, 13e showed the best anti-glioma activity, with an IC50 value up to 0.53 μM, providing a promising lead compound for new anti-glioma drug development. Mechanistic analyses showed that 13e suppressed the MDM4 protein expression, upregulated the p53 protein level, and induced cell cycle arrest at G2/M phase and apoptosis based on Western blot and flow cytometry assays.

Fibroblast growth factor pathway promotes glycolysis by activating LDHA and suppressing LDHB in a STAT1-dependent manner in prostate cancer

BackgroundThe initiation of fibroblast growth factor 1 (FGF1) expression coincident with the decrease of FGF2 expression is a well-documented event in prostate cancer (PCa) progression. Lactate dehydrogenase A (LDHA) and LDHB are essential metabolic products that promote tumor growth. However, the relationship between FGF1/FGF2 and LDHA/B-mediated glycolysis in PCa progression is not reported. Thus, we aimed to explore whether FGF1/2 could regulate LDHA and LDHB to promote glycolysis and explored the involved signaling pathway in PCa progression.MethodsIn vitro studies used RT‒qPCR, Western blot, CCK-8 assays, and flow cytometry to analyze gene and protein expression, cell viability, apoptosis, and cell cycle in PCa cell lines. Glycolysis was assessed by measuring glucose consumption, lactate production, and extracellular acidification rate (ECAR). For in vivo studies, a xenograft mouse model of PCa was established and treated with an FGF pathway inhibitor, and tumor growth was monitored.ResultsFGF1, FGF2, and LDHA were expressed at high levels in PCa cells, while LDHB expression was low. FGF1/2 positively modulated LDHA and negatively modulated LDHB in PCa cells. The depletion of FGF1, FGF2, or LDHA reduced cell proliferation, induced cell cycle arrest, and inhibited glycolysis. LDHB overexpression showed similar inhibitory effect on PCa cells. Mechanistically, we found that FGF1/2 positively regulated STAT1 and STAT1 transcriptionally activated LDHA expression while suppressed LDHB expression. Furthermore, the treatment of an FGF pathway inhibitor suppressed PCa tumor growth in mice.ConclusionThe FGF pathway facilitates glycolysis by activating LDHA and suppressing LDHB in a STAT1-dependent manner in PCa.

D-arabinose induces cell cycle arrest by promoting autophagy via p38 MAPK signaling pathway in breast cancer

Breast cancer patients often have a poor prognosis largely due to lack of effective targeted therapy. It is now well established that monosaccharide enhances growth retardation and chemotherapy sensitivity in tumor cells. We investigated whether d-arabinose has capability to restrict the proliferation of tumor cells and its mechanism. Here, we report that d-arabinose induced cytotoxicity is modulated by autophagy and p38 MAPK signaling pathway in breast cancer cell lines. The proliferation of cells was evaluated by CCK-8 and Colony formation assay. The distribution of cells in cell cycle phases was analyzed by flow cytometry. Cell cycle, autophagy and MAPK signaling related proteins were detected by western blotting. Mouse xenograft model was used to evaluate the efficacy of d-arabinose in vivo. The proliferation of cells was dramatically inhibited by d-arabinose exposure in a dose-dependent manner, which was relevant to cell cycle arrest, as demonstrated by G2/M cell cycle restriction and ectopic expression of cell cycle related proteins. Mechanistically, we further identified that d-arabinose is positively associated with autophagy and the activation of the p38 MAPK signaling in breast cancer. In contrast, 3-Ma or SB203580, the inhibitor of autophagy or p38 MAPK, reversed the efficacy of d-arabinose. Additionally, d-arabinose in vivo treatment could significantly inhibit xenograft growth of breast cancer cells. Our findings were the first to reveal that d-arabinose triggered cell cycle arrest by inducing autophagy through the activation of p38 MAPK signaling pathway in breast cancer cells.

A Carbon 21 Steroidal Glycoside with Pregnane Skeleton from Cynanchum atratum Bunge Promotes Megakaryocytic and Erythroid Differentiation in Erythroleukemia HEL Cells through Regulating Platelet-Derived Growth Factor Receptor Beta and JAK2/STAT3 Pathway.

Erythroleukemia is a rare form of acute myeloid leukemia (AML). Its molecular pathogenesis remains vague, and this disease has no specific therapeutic treatments. Previously, our group isolated a series of Carbon 21 (C-21) steroidal glycosides with pregnane skeleton from the root of Cynanchum atratum Bunge. Among them, we found that a compound, named BW18, can induce S-phase cell cycle arrest and apoptosis via the mitogen-activated protein kinase (MAPK) pathway in human chronic myeloid leukemia K562 cells. However, its anti-tumor activity against erythroleukemia remains largely unknown. In this study, we aimed to investigate the anti-erythroleukemia activity of BW18 and the underlying molecular mechanisms. Our results demonstrated that BW18 exhibited a good anti-erythroleukemia activity in the human erythroleukemia cell line HEL and an in vivo xenograft mouse model. In addition, BW18 induced cell cycle arrest at the G2/M phase and promoted megakaryocytic and erythroid differentiation in HEL cells. Furthermore, RNA sequencing (RNA-seq) and rescue assay demonstrated that overexpression of platelet-derived growth factor receptor beta (PDGFRB) reversed BW18-induced megakaryocytic differentiation in HEL cells, but not erythroid differentiation. In addition, the network pharmacology analysis, the molecular docking and cellular thermal shift assay (CETSA) revealed that BW18 could inactivate Janus tyrosine kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, which might mediate BW18-induced erythroid differentiation. Taken together, our findings elucidated a novel role of PDGFRB in regulating erythroleukemia differentiation and highlighted BW18 as an attractive lead compound for erythroleukemia treatment.

New Carbothioamide and Carboxamide Derivatives of 3-Phenoxybenzoic Acid as Potent VEGFR-2 Inhibitors: Synthesis, Molecular Docking, and Cytotoxicity Assessment.

Because of the well-established link between angiogenesis and tumor development, the use of antiangiogenic therapeutics, such as those targeting VEGFR-2, presents a promising approach to cancer treatment. In the current study, a set of five hydrazine-1-- carbothioamide (compounds 3a-e) and three hydrazine-1-carboxamide derivatives (compounds 4a-c) were successfully synthesized from 3-phenoxybenzoic acid. These compounds were specially created as antiproliferative agents with the goal of targeting cancer cells by inhibiting VEGFR-2 tyrosine kinase. The new derivatives were synthesized by conventional organic methods, and their structure was versified by IR, 1HNMR, 13CNMR, and mass spectroscopy. In silico investigation was carried out to identify the compounds' target, molecular similarity, ADMET, and toxicity profile. The cytotoxic activity of the prepared compounds was evaluated in vitro against three human cancer cell lines (DLD1 colorectal adenocarcinoma, HeLa cervical cancer, and HepG2 hepatocellular carcinoma). The effects of the leading compound on cell cycle progression and apoptosis induction were investigated by flow cytometry, and the specific apoptotic pathway triggered by the treatment was evaluated by RT-PCR and immunoblotting. Finally, the inhibitory activities of the new compounds against VEGFR-2 was measured. The designed derivatives exhibited comparable binding positions and interactions to the VEGFR-2 binding site to that of sorafenib (a standard VEGFR-2 tyrosine kinase inhibitor), as determined by molecular docking analysis. Compound 4b was the most cytotoxic compound, achieving the lowest IC50 against HeLa cells. Compound 4b, a strong representative of the synthesized series, induced cell cycle arrest at the G2/M phase, increased the proportion of necrotic and apoptotic HeLa cells, and activated caspase 3. The EC50 value of compound 4b against VEGFR-2 kinase activity was comparable to sorafenib's. Overall, the findings suggest that compound 4b has a promising future as a starting point for the development of new anticancer drugs.

Synthesis and antitumor activities of novel 3-(6-aminopyridin-3-yl)benzamide derivatives: Inducing cell cycle arrest and apoptosis via AURKB transcription inhibition

Here, a series of 3-(6-aminopyridin-3-yl) benzamide derivatives were designed and synthesized. Cell viability assay indicated that most compounds exhibited potent antiproliferative activity against all the tested cancer cells. Among them, compound 7l displayed the best antiproliferative activity particularly in A549 cells, with an IC50 value of 0.04 ± 0.01 μM. RNA-seq analysis was employed to explore the potential pathways related to the antiproliferative activity of compound 7l. The data revealed that 7l exerted antiproliferative activity mainly by regulating cell cycle, DNA replication and p53 signaling pathway. Indeed, compound 7l induced G2/M phase arrest by AURKB transcription inhibition and resulted in cell apoptosis via p53 signaling pathway. Most importantly, compound 7l demonstrated potent antitumor activity in A549 xenograft tumor model. Collectively, 7l might be a promising lead compound for the development of new therapeutic agents for AURKB overexpressed or mutated cancers.

The anti-non-small cell lung cancer effect of Diosbulbin B: Targeting YY1 induced cell cycle arrest and apoptosis

BackgroundToxic components frequently exhibit unique characteristics and activities, offering ample opportunities for the advancement of anti-cancer medications. As the main hepatotoxic component of Dioscorea bulbifera L. (DB), Diosbulbin B (DIOB) has been widely studied for its anti-tumor activity at nontoxic doses. However, the effectiveness and mechanism of DIOB against non-small cell lung cancer (NSCLC) remains unclear. PurposeTo evaluate the anti-NSCLC activity of DIOB and to elucidate the specific mechanism of action. MethodThe effect of DIOB on NSCLCL in vitro was evaluated through CCK8, colony formation, and flow cytometry. The in vivo efficacy and safety of DIOB in treating NSCLC were assessed using various techniques, including HE staining, tunel staining, immunohistochemistry, and biochemical index detection. To understand the underlying mechanism, cell transfection, western blotting, molecular docking, cellular thermal shift assay (CESTA), and surface plasmon resonance (SPR) were employed for investigation. ResultsDIOB effectively hindered the progression of NSCLC both in vitro and in vivo settings at a no-observed-adverse-effect concentration (NOAEC) and a safe dosage. Specifically, DIOB induced significant G0/G1 phase arrest and apoptosis in A549, PC-9, and H1299 cells, while also notably inhibiting the growth of subcutaneous tumors in nude mice. Mechanistically, DIOB could directly interact with oncogene Yin Yang 1 (YY1) and inhibit its expression. The reduction in YY1 resulted in the triggering of the tumor suppressor P53, which induced cell cycle arrest and apoptosis in NSCLC cells by inhibiting the expression of Cyclin A2, B2, CDK1, CDK2, CDK4, BCL-2, and inducing the expression of BAX. In NSCLC cells, the induction of G0/G1 phase arrest and apoptosis by DIOB was effectively reversed when YY1 was overexpressed or P53 was knocked down. Importantly, we observed that DIOB exerted the same effect by directly influencing the expression of YY1-regulated c-Myc and BIM, particularly in the absence of P53. ConclusionFor the inaugural investigation, this research unveiled the anti-NSCLC impact of DIOB, alongside its fundamental mechanism. DIOB has demonstrated potential as a treatment agent for NSCLC due to its impressive efficacy in countering NSCLC.

Synthesis and in vitro antitumor evaluation of new thieno[2,3-d]pyrimidine derivatives as EGFR and DHFR inhibitors

New thienopyrimidine derivatives 2–16 have been synthesized and their in vitro cytotoxicity was evaluated against five different human cancer cell lines HCT-116, Hela, MDA-MB-231, MCF7 and PC3. Compounds 6e, 7a, 7b, 7d, 10c and 10e displayed the highest antitumor activity against all tested cell lines compared to Doxorubicin. Enzyme inhibition assay revealed that compounds 6e and 10e showed high inhibitory activity against EGFR-TK, with IC50 values of 0.133 and 0.151 µM, compared to Olmutinib (IC50 = 0.028 µM); while the highest DHFR inhibitory activity was shown by compounds 7d and 10e with IC50 values of 0.462 and 0.541 µM, compared to Methotrexate (IC50 = 0.117 µM). Cell cycle analysis following a flow cytometric study using colorectal HCT-116 cancer cell line proved that compound 6e induced cell cycle arrest in G0-G1 phase, while compound 10e arrested the cell cycle at both G0-G1 and S phases. Additionally, both compounds (6e and 10e) were potently able to induce apoptosis in HCT-116 cell line. Docking results of compounds 6e and 10e into the pocket of EGFR active site showed their similar main binding features with Olmutinib, while compounds 7d and 10e showed only moderate fitting into DHFR compared to methotrexate. In silico studies revealed that most of the tested compounds obeyed Lipinski’s RO5 and showed positive drug likeness scores.

Nogo-B Silencing Expedites the Senescence of Platelet-Derived Growth Factor-BB-Induced Human Hepatic Stellate Cells Via Autophagy.

Liver fibrosis is a severe liver pathology in response to chronic or iterative liver injury. Senescence has emerged as a protective mechanism against liver fibrosis. Nogo-B has been well established as a significant contributor to liver fibrosis. Nonetheless, researches regarding the role of Nogo-B in cell senescence during liver fibrosis are few. In platelet-derived growth factor-BB (PDGF-BB)-treated human hepatic stellate cell line LX-2, cell proliferation was assayed by CCK-8 method. Western blotting estimated the expression of Nogo-B and fibrosis markers. After Nogo-B was silenced in LX-2 cells pretreated by an autophagy activator Rapamycin and PDGF-BB, CCK-8 method was used to assess cell proliferation. Fibrosis was measured by western blotting and immunofluorescence. Cell cycle was subjected to flow cytometry analysis and cell senescence was evaluated by SA-β-gal staining. Immunofluorescence staining assessed autophagy. Nogo-B was elevated in PDGF-BB-exposed LX-2 cells. Nogo-B silencing suppressed the proliferation, fibrosis, and autophagy while induced cell cycle arrest and senescence of LX-2 cells. Additionally, pretreatment with Rapamycin partially restored the effects of Nogo-B knockdown on the autophagy, proliferation, fibrosis, cell cycle, and senescence of LX-2 cells upon exposure to PDGF-BB. Collectively, inactivation of autophagy mediated by Nogo-B deficiency might elicit protective activities against the development of liver fibrosis.

Pan-cancer analysis of LRRC59 with a focus on prognostic and immunological roles in hepatocellular carcinoma.

LRRC59 is a leucine-rich repeats-containing protein located in the endoplasmic reticulum (ER), it serves as a prognostic marker in several cancers. However, there has been no systematic analysis of its role in the tumor immune microenvironment, nor its predictive value of prognosis and immunotherapy response in different cancers. A comprehensive pan-cancer analysis of LRRC59 was conducted from various databases to elucidate the associations between its expression and the prognosis of cancer, genetic alterations, tumor metabolism, and tumor immunity. Additionally, further functional assays were performed in hepatocellular carcinoma (HCC) to study its biological role in regulating cell proliferation, migration, apoptosis, cell cycle arrest, and sensitivity to immunotherapy. The pan-cancer analysis reveals a significant upregulation of LRRC59 in pan-cancer, and its overexpression is correlated with unfavorable prognosis in cancer patients. LRRC59 is negatively correlated with immune cell infiltration, tumor purity estimation, and immune checkpoint genes. Finally, the validation in HCC demonstrates LRRC59 is significantly overexpressed in cancer tissue and cell lines, and its knockdown inhibits cell proliferation and migration, promotes cell apoptosis, induces cell cycle arrest, and enhances the sensitivity to immunotherapy in HCC cells. LRRC59 emerges as a novel potential prognostic biomarker across malignancies, offering promise for anti-cancer drugs and immunotherapy.

Green synthesis of silver chloride nanoparticles derived from Artemisia sieberi extract (AgClNPs-ASE) induces cell cycle arrest and triggers apoptosis in human breast (MDA-MB-231) cancer cells

In recent years, metallic nanoparticles have attracted tremendous attention in nanomedicine. Here, we report green synthesis and determination of silver chloride nanoparticles synthesized using Artemisia sieberi extract (AgClNPs-ASE) and its anticancer properties against human breast cancer cells. Numerous techniques, such as X-ray diffraction (XRD), UV-visible spectra, transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive spectra (SEM–EDS), and dynamic light scattering (DLS) analysis determined the morphology characteristics and size of the obtained nanoparticles. Cytotoxic properties of AgClNPs-ASE were carried out toward human breast cancer MDA-MB-231 cells and nontumorigenic HEK293 cells. AgClNPs-ASE revealed better efficacy toward breast cancer cells and was relatively less cytotoxic to nontumorigenic cells. Induction of apoptosis was further revealed by Hoechst 33258 dye and dual acridine orange and ethidium bromide (AO/EB) staining and in cells along with upregulation of caspase-8 and 9 proteins. AgClNPs-ASE could trigger the apoptosis by upregulation of early (1.93%) and late (58.86%) apoptosis followed by fluorescein isothiocyanate (FITC)‐Annexin‐V/PI staining and enhanced cell cycle population (sub-G1). AgClNPs-ASE significantly increased NO production in cancer cells. Moreover, qRT-PCR study showed that AgClNPs-ASE treated cells induce increased expression of the LncRNA GAS5 gene. These findings suggest the remarkable apoptosis in cancer cells triggered by AgClNPs-ASE in vitro.

Fungal metabolite altersolanol a exhibits potent cytotoxicity against human placental trophoblasts in vitro via mitochondria-mediated apoptosis.

Altersolanol A, a fungus-derived tetrahydroanthraquinone, has shown cytotoxic effects on multiple cancer cells. However, its reproductive toxicity in humans has not been well-addressed. The present study was aimed at investigating the cytotoxicity of altersolanol A on human placental trophoblasts including choriocarcinoma cell line JEG-3 and normal trophoblast cell line HTR-8/SVneo in vitro. The results showed that altersolanol A inhibited proliferation and colony formation of human trophoblasts, and the choriocarcinoma cells were more sensitive to the compound than the normal trophoblasts. Altersolanol A induced cell cycle arrest at G2/M phase in JEG-3 cells and S phase in HTR-8/SVneo cells, downregulated the expression of cell cycle-related checkpoint proteins, and upregulated the p21 level. Altersolanol A also promoted apoptosis in human trophoblasts via elevating the Bax/Bcl-2 ratio and decreasing both caspase-3 and caspase-9 levels. Meanwhile, altersolanol A suppressed the mitochondrial membrane potential and induced ROS production and cytochrome c release, which activated the mitochondria-mediated intrinsic apoptosis. Moreover, migration and invasion were inhibited upon altersolanol A exposure with downregulation of matrix metalloproteinase (MMP)-2 in JEG-3 cells and MMP-9 in HTR-8/SVneo cells. Mechanically, altersolanol A supplement decreased the phosphorylation of JNK, ERK, and p38, manifesting the inactivation of MAPK signaling pathway in the human trophoblasts. In conclusion, altersolanol A exhibited potential reproductive cytotoxicity against human trophoblasts via promoting mitochondrial-mediated apoptosis and inhibiting the MAPK signaling pathway.

Targeting c-Myc with decoy oligodeoxynucleotide-loaded polycationic nanoparticles inhibits cell growth and induces apoptosis in cancer stem-like cells (NTERA-2).

Anincreaseincancerstemcell(CSC)populations and their resistance tocommontreatmentscouldbearesultofc-Myc dysregulationsincertain cancer cells. In the current study, we investigated anticancer effects of c-Myc decoy ODNs loaded-poly (methacrylic acid-co-diallyl dimethyl ammonium chloride) (PMA-DDA)-coated silica nanoparticles as carriers on cancer-like stem cells (NTERA-2). The physicochemical characteristics of the synthesized nanocomposites (SiO2@PMA-DDA-DEC) were analyzed using FT-IR, DLS, and SEM techniques. UV-Vis spectrophotometer was applied to analyze the release pattern of decoy ODNs from the nanocomposite. Furthermore, uptake, cell viability, apoptosis, and cell cycle assays were used to investigate the anticancer effects of nanocomposites loaded with c-Myc decoy ODNs on NTERA-2 cancer cells. The results of physicochemical analytics demonstrated that SiO2@PMA-DDA-DEC nanocomposites were successfully synthesized. The prepared nanocomposites were taken up by NTERA-2 cells with high efficiency, and could effectively inhibit cell growth and increase apoptosis rate in the treated cells compared to the control group. Moreover, SiO2@PMA-DDA nanocomposites loaded with c-Myc decoy ODNs induced cell cycle arrest at the G0/G1 phase in the treated cells. The conclusion drawn from this study is that c-Myc decoy ODN-loaded SiO2@PMA-DDA nanocomposites can effectively inhibit cell growth and induce apoptosis in NTERA-2 cancer cells. Moreover, given that a metal core is incorporated into this synthetic nanocomposite, it could potentially be used in conjunction with irradiation as part of a decoy-radiotherapy combinational therapy in future investigations.

Marine seaweed endophytic fungi-derived active metabolites promote reactive oxygen species-induced cell cycle arrest and apoptosis in human breast cancer cells.

Endophytic fungi have an abundant sources rich source of rich bioactive molecules with pivotal pharmacological properties. Several studies have found that endophytic fungi-derived bioactive secondary metabolites have antiproliferative, anti-oxidant, and anti-inflammatory properties, but the molecular mechanism by which they induce cell cycle arrest and apoptosis pathways is unknown. This study aimed to determine the molecular mechanism underlying the anticancer property of the endophytic fungi derived active secondary metabolites on human breast cancer cells. In this study, we identified four endophytic fungi from marine seaweeds and partially screened its phytochemical properties by Chromatography-Mass Spectrometry (GC-MS) analysis. Moreover, the molecular mechanism underlying the anticancer property of these active secondary metabolites (FA, FB, FC and FE) on human breast cancer cells were examined on MCF-7 cells by TT assay, Apoptotic assay by Acridine orang/Ethidium Bromide (Dual Staining), DNA Fragmentation by DAPI Staining, reactive oxygen species (ROS) determination by DCFH-DA assay, Cell cycle analysis was conducted Flow cytometry and the apoptotic signalling pathway was evaluated by westernblot analysis. Doxorubicin was used as a positive control drug for this experiment. The GC-MS analysis of ethyl acetate extract of endophytic fungi from the marine macro-algae revealed the different functional groups and bioactive secondary metabolites. From the library, we observed the FC (76%), FB (75%), FA (73%) and FE (71%) have high level of antioxidant activity which was assessed by DPPH scavenging assay. Further, we evaluated the cytotoxic potentials of these secondary metabolites on human breast cancer MCF-7 cells for 24h and the IC50 value were calculated (FA:28.62 ± 0.3µg/ml, FB:49.81 ± 2.5µg/ml, FC:139.42 ± µg/ml and FE:22.47 ± 0.5µg/ul) along with positive control Doxorubicin 15.64 ± 0.8µg/ml respectively by MTT assay. The molecular mechanism by which the four active compound induced apoptosis via reactive oxygen species (ROS) and cell cycle arrest in MCF-7 cells was determined H2DCFDA staining, DAPI staining, Acridine orange and ethidium bromide (AO/EtBr) dual staining, flowcytometry analysis with PI staining and apoptotic key regulatory proteins expression levels measured by westernblot analysis. Our findings, revealed the anticancer potential of endophytic fungi from marine seaweed as a valuable source of bioactive compounds with anticancer properties and underscore the significance of exploring marine-derived endophytic fungi as a promising avenue for the development of novel anticancer agents. Further investigations are necessary to isolate and characterize specific bioactive compounds responsible for these effects and to validate their therapeutic potential in preclinical and clinical settings.

Design, synthesis and biological evaluation of new RNF126-based p300/CBP degraders

Histone acetyltransferase CREB-binding protein (CBP) and its homologous protein p300 are key transcriptional activators that can activate oncogene transcription, which present promising targets for cancer therapy. Here, we designed and synthesized a series of p300/CBP targeted low molecular weight PROTACs by assembling the covalent ligand of RNF126 E3 ubiquitin ligase and the bromodomain ligand of the p300/CBP. The optimal molecule A8 could effectively degrade p300 and CBP through the ubiquitin–proteasome system in time- and concentration-dependent manners, with half-maximal degradation (DC50) concentrations of 208.35/454.35 nM and 82.24/79.45 nM for p300/CBP in MV4-11 and Molm13 cell lines after 72 h of treatment. And the degradation of p300/CBP by A8 is dependent on the ubiquitin–proteasome pathway and its simultaneous interactions with the target proteins and RNF126. A8 exhibits good antiproliferative activity in a series of p300/CBP-dependent cancer cells. It could transcriptionally inhibit the expression of c-Myc, induce cell cycle arrest in the G0/G1 phase and apoptosis in MV4-11 cells. This study thus provided us a new chemotype for the development of drug-like PROTACs targeting p300/CBP, which is expected to be applied in cancer therapy.

Potential anticancer activities of schisandracaurin C against NTERA-2 cancer stem cells

Cancer is a global concern and the potential targeting of cancer stem cells (CSCs) has gained major attention in anticancer drug discovery research. Various natural compounds have shown promising effects in suppressing cancer, prompting scientific interest. In this study, we investigated the anti-CSC properties of schisandracaurin C, a novel compound derived from the Vietnamese plant Schisandra cauliflora. To evaluate its anti-CSC efficacy, we employed the MTT assay, flow cytometry analysis, the caspase-3 assay and a three-dimensional cell culture method, focusing on the teratocarcinoma NTERA-2 cells. Our findings revealed that schisandracaurin C inhibited the growth of NTERA-2 cells with an IC50 value of 16.61±0.13 μM, which was significantly lower than that on HEK-293A healthy embryonic kidney cells (22.72±0.02 μM) (P<0.05). Schisandracaurin C was toxic to NTERA-2 cells within three-dimensional tumorspheres (IC50: 33.47±1.45 μM). The anti-CSC effects of schisandracaurin C on NTERA-2 cells were mediated through apoptosis, as evidenced by increased caspase-3 activity. Schisandracaurin C induced cell cycle arrest at the S phase in NTERA-2 cells. These findings highlight the potential of schisandracaurin C as a promising anti-CSC compound, which warrants further mechanistic and clinical investigations.

Exploring CDKN1A Upregulation Mechanisms: Insights into Cell Cycle Arrest Induced by NC2603 Curcumin Analog in MCF-7 Breast Cancer Cells.

Breast cancer stands out as one of the most prevalent malignancies worldwide, necessitating a nuanced understanding of its molecular underpinnings for effective treatment. Hormone receptors in breast cancer cells substantially influence treatment strategies, dictating therapeutic approaches in clinical settings, serving as a guide for drug development, and aiming to enhance treatment specificity and efficacy. Natural compounds, such as curcumin, offer a diverse array of chemical structures with promising therapeutic potential. Despite curcumin's benefits, challenges like poor solubility and rapid metabolism have spurred the exploration of analogs. Here, we evaluated the efficacy of the curcumin analog NC2603 to induce cell cycle arrest in MCF-7 breast cancer cells and explored its molecular mechanisms. Our findings reveal potent inhibition of cell viability (IC50 = 5.6 μM) and greater specificity than doxorubicin toward MCF-7 vs. non-cancer HaCaT cells. Transcriptome analysis identified 12,055 modulated genes, most notably upregulation of GADD45A and downregulation of ESR1, implicating CDKN1A-mediated regulation of proliferation and cell cycle genes. We hypothesize that the curcumin analog by inducing GADD45A expression and repressing ESR1, triggers the expression of CDKN1A, which in turn downregulates the expression of many important genes of proliferation and the cell cycle. These insights advance our understanding of curcumin analogs' therapeutic potential, highlighting not just their role in treatment, but also the molecular pathways involved in their activity toward breast cancer cells.

Abstract SoA2-02: Implications of therapy induced senescence in breast cancer

Abstract The goal of breast cancer treatment is to cause cellular stress sufficient to kill and eliminate the tumor cells. Unfortunately, in many cases cancer cells survive and are not removed by surgery and thus can cause relapse and eventual mortality. Surviving cells have necessarily avoided both intrinsic (e.g., apoptosis) and extrinsic (e.g., immune surveillance) mechanisms of death. Studies over the last 20 years have shown that chemotherapy-treated breast cancer cells can evade cell death by activating programs of cellular senescence mediated by the tumor suppressor p53. While p53 can induce apoptosis in response to stress in some cell types, in breast cancer, p53 preferentially induces cell cycle arrest and senescence in response to chemotherapy. Data show that patients with breast cancers that are wild type for TP53 have a much lower probability of being eradicated by chemotherapy, and have a much shorter survival, compared to patients with TP53 mutant tumors. Human and mouse mammary tumors induce many markers of senescence after chemotherapy treatment, including those associated with cell cycle arrest and the senescence associated secretory phenotype (SASP). These arrested tumors evade death from mitotic catastrophe and can block apoptotic programs via elevated activity of BCL2 family members. More recent studies have addressed how induction of senescence deters immune surveillance. Breast cancer cells exposed to chemotherapy reorganize chromatin structure that amplifies stromal derived signals that stimulate expression of many immune genes, including checkpoint ligands such as PD-L1 and Galectin-9. Further, p53 can directly transactivate other immune modulatory genes such as CD80. Collectively, these properties of senescent cells enable their persistence following treatment and contribute to their potential to drive relapse. These same properties, however, can also be exploited as vulnerabilities to therapeutics such as senolytic drugs that target reliance on BCL2 family members or immunotherapies that target PD-L1 expression. Citation Format: J. Jackson. Implications of therapy induced senescence in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr SoA2-02.