Cell Cycle Progression Research Articles

Resmethrin disrupts mitochondria-associated membranes and activates endoplasmic reticulum stress, leading to proliferation inhibition in cultured mouse Leydig and Sertoli cells

Resmethrin, a pyrethroid pesticide used to control insects, is toxic to non-target organisms and other mammals. However, little is known about the reproductive toxicity of resmethrin in the testes, or its mechanism of toxicity. In this study, we investigated the testicular toxicity of resmethrin on mouse Leydig (TM3) and Sertoli (TM4) cells, focusing on the mitochondria and endoplasmic reticulum (ER). We found that resmethrin inhibited proliferation and cell cycle progression and disrupted mitochondrial membrane potential (MMP; ΔΨ) in TM3 and TM4 cells. In particular, resmethrin exposure significantly reduced the expression of mitochondria-associated membranes (MAMs) proteins, such as Vapb, Vdac, and Grp75, in both cell lines. Resmethrin also disrupts calcium homeostasis in the mitochondrial matrix and cytoplasm. In addition, resmethrin activates oxidative stress-mediated ER stress signals. Finally, we confirmed that 4-PBA, an ER stress inhibitor, restored the growth of TM3 and TM4 cells, which was decreased by resmethrin. Therefore, we confirmed that resmethrin hampered MAMs and activated ER stress, thus suppressing TM3 and TM4 cell proliferation.

THE EPIGENETIC REGULATORY PROTEIN CBX2 AS A NOVEL THERAPEUTIC TARGET FOR GLIOBLASTOMA

Abstract AIMS Glioblastoma (GBM) is the deadliest and most common form of brain tumour. The average length of survival for GBM patients remains low, in part, due to a lack of targeted therapeutics. Identification and validation of novel therapeutic targets is therefore crucial. Chomobox 2 (CBX2; a component of polycomb repressive complex 1 (PRC1)), represses gene expression and has a pro-oncogenic role in several aggressive cancer subtypes. CBX2 expression is elevated in GBM, however, very little is known about its role in this deadly disease. We aim to assess the phenotypic and gene expression effects of preventing CBX2-chromatin interaction in patient-derived GBM cell models, and to determine the functional mechanisms by which CBX2 promotes GBM progression; thereby determining its potential as a novel therapeutic target. METHOD Crucial to impactful target validation is the use of translationally relevant models, this study utilises a 3D spheroid model, using patient-derived cells, which more closely recapitulates the in vivo tumour microenvironment. GBM cell monolayers and spheroids were treated with SW2_152F, a selective CBX2 inhibitor. The phenotypic effects of CBX2 inhibition were assessed by cell count, CellTiter-Glo viability assays, fluorescence microscopy, and flow cytometry. Genes and biological pathways differentially regulated following CBX2 inhibition were assessed by RNA-sequencing and Gene Set Enrichment Analysis (GSEA). RESULTS Inhibition of CBX2 induced cell death and reduced cell viability in both 2D and 3D GBM cultures. RNA-seq and GSEA of SW2_152F-treated cells identified dysregulation of gene signatures involved in pro-oncogenic MYC and E2F signalling pathways, and dysregulation of genes associated with G2/M cell cycle progression. CONCLUSION Preventing CBX2-chromatin interaction induces GBM cell death. Further research will identify CBX2- chromatin binding sites to characterise the activity and direct regulatory role of CBX2 in GBM. Furthermore, we will assess the phenotypic and gene expression effects of CBX2 inhibition and depletion on ex vivo maintained GBM tissue biopsies.

SUMO: A new perspective to decipher fibrosis.

Fibrosis is characterized by excessive extracellular matrix (ECM) deposition resulting from dysregulated wound healing and connective tissue repair mechanisms. Excessive accumulation of ECM leads to fibrous tissue formation, impairing organ function and driving the progression of various fibrotic diseases. Recently, the role of small ubiquitin-like modifiers (SUMO) in fibrotic diseases has attracted significant attention. SUMO-mediated SUMOylation, a highly conserved posttranslational modification, participates in a variety of biological processes, including nuclear-cytosolic transport, cell cycle progression, DNA damage repair, and cellular metabolism. Conversely, SUMO-specific proteases cleave the isopeptide bond of SUMO conjugates, thereby regulating the deSUMOylation process. Mounting evidence indicates that SUMOylation and deSUMOylation regulate the functions of several proteins, such as Smad3, NF-κB, and promyelocytic leukemia protein, which are implicated in fibrotic diseases like liver fibrosis, myocardial fibrosis, and pulmonary fibrosis. This review summarizes the role of SUMO in fibrosis-related pathways and explores its pathological relevance in various fibrotic diseases. All evidence suggest that the SUMO pathway is important targets for the development of treatments for fibrotic diseases.

Exploring Molecular Signatures in Early-Stage Pancreatic Ductal Adenocarcinoma: Implications for Patient Management and Therapeutic Strategies

Abstract Introduction/Objective Pancreatic ductal adenocarcinoma (PDAC) poses significant challenges to patient survival, predominantly due to its tendency for late-stage diagnosis and high rates of post-surgical cancer recurrence. Therefore, a comprehensive understanding of the molecular characteristics associated with the early stages of PDAC is imperative. This understanding holds the potential to improve patient treatment strategies by enabling targeted interventions and personalized therapies. Methods/Case Report Initially, RNA-seq datasets of early-stage PDAC cases (stages IA, IB, IIA, and IIB, all without distant metastasis; M0) were extracted from the GEO database. Subsequently, the datasets were analyzed in four distinct groups, and differentially expressed genes were identified within each group. Group 1 compared T1T2 cases with T3 cases (T: primary tumor), irrespective of N status (N: regional lymph nodes), while group 2 compared N0 cases with N1 cases, regardless of T status. Group 3 included comparisons between T1T2N0 cases and T3N0 cases, and group 4 compared T1T2N1 cases with T3N1 cases. Utilizing a Venn diagram, commonalities between gene expression profiles were isolated. Afterward, gene ontology and signaling pathways were determined using KEGG and Enrichr. Finally, a protein network was constructed, and the proteins were evaluated using the GEPIA and TCGA clinical databases. Results (if a Case Study enter NA) The study encompassed a total of 43 cases, with 25 (58.1%) being male and 18 (41.9%) female. The mean age of the participants was 64.4 years. In group 1, the expression levels of MUC5AC, AKAP13, and SPG7 were significantly upregulated in T3 cases. In group 2, STAB1, PDLIM1, and MTUS1 emerged as the top upregulated genes in N1 cases. Group 3 exhibited notable upregulation of CCNL2, CEACAM6, and TSPAN3 in T3N0 cases, while group 4 demonstrated marked upregulation of LTBR, AKAP12, and BOP1 in T3N1 cases. These genes exhibited diverse functions in PDAC progression. They contributed to the regulation of gene expression and cell cycle progression, modulating cell proliferation, inhibiting tumor growth, regulating cell signaling, and were involved in cytoskeletal organization. Conclusion The upregulated genes in cases with the T3 and/or N1 staging components may shed light on the potential mechanisms of progression from stage IA/B to stage IIA/B in PDAC cases. Furthermore, the identified genetic alterations may hold potential therapeutic and prognostic applications for future use in the early stages of PDAC.

AKR1B1-dependent fructose metabolism enhances malignancy of cancer cells.

Fructose metabolism has emerged as a significant contributor to cancer cell proliferation, yet the underlying mechanisms and sources of fructose for cancer cells remain incompletely understood. In this study, we demonstrate that cancer cells can convert glucose into fructose through a process called the AKR1B1-mediated polyol pathway. Inhibiting the endogenous production of fructose through AKR1B1 deletion dramatically suppressed glycolysis, resulting in reduced cancer cell migration, inhibited growth, and the induction of apoptosis and cell cycle arrest. Conversely, the acceleration of endogenous fructose through AKR1B1 overexpression has been shown to significantly enhance cancer cell proliferation and migration with increased S cell cycle progression. Our findings highlight the crucial role of endogenous fructose in cancer cell malignancy and support the need for further investigation into AKR1B1 as a potential cancer therapeutic target.

Decoding Cancer through Silencing the Mitochondrial Gatekeeper VDAC1.

Mitochondria serve as central hubs for regulating numerous cellular processes that include metabolism, apoptosis, cell cycle progression, proliferation, differentiation, epigenetics, immune signaling, and aging. The voltage-dependent anion channel 1 (VDAC1) functions as a crucial mitochondrial gatekeeper, controlling the flow of ions, such as Ca2+, nucleotides, and metabolites across the outer mitochondrial membrane, and is also integral to mitochondria-mediated apoptosis. VDAC1 functions in regulating ATP production, Ca2+ homeostasis, and apoptosis, which are essential for maintaining mitochondrial function and overall cellular health. Most cancer cells undergo metabolic reprogramming, often referred to as the "Warburg effect", supplying tumors with energy and precursors for the biosynthesis of nucleic acids, phospholipids, fatty acids, cholesterol, and porphyrins. Given its multifunctional nature and overexpression in many cancers, VDAC1 presents an attractive target for therapeutic intervention. Our research has demonstrated that silencing VDAC1 expression using specific siRNA in various tumor types leads to a metabolic rewiring of the malignant cancer phenotype. This results in a reversal of oncogenic properties that include reduced tumor growth, invasiveness, stemness, epithelial-mesenchymal transition. Additionally, VDAC1 depletion alters the tumor microenvironment by reducing angiogenesis and modifying the expression of extracellular matrix- and structure-related genes, such as collagens and glycoproteins. Furthermore, VDAC1 depletion affects several epigenetic-related enzymes and substrates, including the acetylation-related enzymes SIRT1, SIRT6, and HDAC2, which in turn modify the acetylation and methylation profiles of histone 3 and histone 4. These epigenetic changes can explain the altered expression levels of approximately 4000 genes that are associated with reversing cancer cells oncogenic properties. Given VDAC1's critical role in regulating metabolic and energy processes, targeting it offers a promising strategy for anti-cancer therapy. We also highlight the role of VDAC1 expression in various disease pathologies, including cardiovascular, neurodegenerative, and viral and bacterial infections, as explored through siRNA targeting VDAC1. Thus, this review underscores the potential of targeting VDAC1 as a strategy for addressing high-energy-demand cancers. By thoroughly understanding VDAC1's diverse roles in metabolism, energy regulation, mitochondrial functions, and other cellular processes, silencing VDAC1 emerges as a novel and strategic approach to combat cancer.

Transforming growth factor-beta and Epithelial-mesenchymal transition is considered an attractive pivotal Genetic-Biomarker for Hepatocellular carcinoma with hepatitis C virus-infection patients

Abstract Introduction/Objective Hepatocellular carcinoma (HCC) is the most common cause of cancer worldwide. HCC is induced by hepatitis C-virus (HCV) which represents a major health problem in Egypt. The transforming growth factor- beta (TGF-β) is a potent cytokine that has a multifunctional pro-fibrotic activity, for enhancing liver-inflammation, fibrosis, tumor-progression, and metastasis. TGF-β has a vital role in the regulation of tumorigenesis, by controlling epithelial-mesenchymal-transition (EMT), apoptosis, proliferation, and differentiation process. The dysregulation of TGF-β, Wnt/β-catenin signaling pathways, by HCV-core protein is implicated in the development of HCC. Methods/Case Report The study aims to determine the effect of the HCV-infection in HCC patients with a set of growth-factors, EMT, and anti-apoptotic protein expression levels by using western blotting and immunohistochemistry staining analysis. Results (if a Case Study enter NA) These results observed an insignificant increase in the expression of TGF-β protein for HCC/HCV-infected cells compared to the HCV-uninfected cells, and the expression of the β-catenin protein level is elevated in the nucleus. Also, it showed that Bcl-2 protein is a significant increase in HCV-infected when compared to HCV-free groups. Positive staining for p53 protein was detected in the HCC/HCV-infected, more than in HCC/HCV-uninfected cells. This data indicated that the core-protein of HCV can switch TGF-β from a tumor suppressor to a tumor promoter by suppressing apoptosis of hepatocytes and increasing EMT expression by activation of Wnt/β-catenin signaling pathway. Therefore, HCV-core protein enhances the nuclear accumulation of β-catenin expression protein to activate downstream target genes, which regulate cell-growth and cell-cycle progression. Conclusion It is speculated that HCV may exert an anti-apoptotic effect, and thus enhance tumorigenesis. Also, the accumulation of nuclear Wnt/β-catenin and p53 correlates with TGF-β expression, typically a late event in hepato- carcinogenesis. Taken together, the expression level of TGF-β, Wnt/β-catenin, Bcl-2, and p53 genotype in HCV is considered an indicator of shortened survival in patients, and may be an attractive clinically pivotal genetic biomarker to mediate liver pathogenesis.

AURKA inhibition shows promise as a therapeutic strategy for ARID1A-mutant colorectal cancer

PurposeMutations in ARID1A frequently occur in colorectal cancer (CRC) cells. However, there are currently no clinical treatment options specifically addressing this aberration. The preliminary in vitro experiments revealed a synthetic lethal interaction between ARID1A and Aurora kinase A (AURKA) in colorectal cancer (CRC) cells.MethodsWe collected samples from 80 CRC patients and evaluated the efficacy of AURKA inhibitor (AURKAi) using the ATP-tumor chemosensitivity assay (ATP-TCA) on untreated ARID1A-proficient (ARID1A +) and ARID1A-deficient (ARID1A-) CRC patient samples. In addition, we validated this result by a clonogenic assay. Additionally, we examined the effects of AURKA inhibitors on cell cycle progression and apoptosis in ARID1A + and ARID1A- CRC patient samples using flow cytometry.ResultsThe results showed that AURKAi selectively inhibited the growth of ARID1A- CRC cells. Furthermore, AURKA inhibitors significantly increased G2/M arrest and induced apoptosis in ARID1A- cells.ConclusionWe believe that AURKAi hold promise as potential therapeutics for ARID1A mutation colorectal cancer patients.

Helical coiled nucleosome chromosome architectures during cell cycle progression

Recent studies showed an interphase chromosome architecture-a specific coiled nucleosome structure-derived from cryopreserved EM tomograms, and dispersed throughout the nucleus. The images were computationally processed to fill in the missing wedges of data caused by incomplete tomographic tilts. The resulting structures increased z-resolution enabling an extension of the proposed architecture to that of mitotic chromosomes. Here, we provide additional insights into the chromosome architecture that was recently published [M. Elbaum et al., Proc. Natl. Acad. Sci. U.S.A. 119, e2119101119 (2022)]. We build on the defined chromosomes time-dependent structures in an effort to probe their dynamics. Variants of the coiled chromosome structures, possibly further defining specific regions, are discussed. We propose, based on generalized specific uncoiling of mitotic chromosomes in telophase, large-scale reorganization of interphase chromosomes. Chromosome territories, organized as micron-sized small patches, are constructed, satisfying complex volume considerations. Finally, we unveiled the structures of replicated coiled chromosomes, still attached to centromeres, as part of chromosome architecture.

Circ_0008035 Promotes Gastric Cancer Development via the miR-429/SMAD2 Cascade.

The vital roles of circular RNAs (circRNAs) in human tumorigenesis have attracted more attention. Circ_0008035 is one of the most up-regulated circRNAs in gastric cancer (GC). Herein, we explored the associated mechanism of circ_0008035 in GC. EdU incorporation experiments were performed to monitor cell proliferation ability. Cell cycle progression, apoptosis, angiogenesis, migration, and invasion were analyzed using flow cytometry, Tube formation, and Transwell assays respectively. Protein expression was detected by Western blot. Dual-luciferase reporter experiments were applied to demonstrate the relationship between circ_0008035 or SMAD family member 2 (SMAD2) and microRNA-429 (miR-429). Mouse xenograft assays were conducted for evaluation of the role of circ_0008035 in vivo. Circ_0008035 content was elevated in GC tissues (P < .0001) and cell lines (P < .001), and its deficiency hindered GC cell proliferation (P < .01), HUVEC angiogenesis (P < .05), and GC cell metastasis (P < .01) and triggered apoptosis (P < .01). Circ_0008035 could sponge miR-429 to up-regulate SMAD2 expression (P < .0001). Circ_0008035 absence restrained tumor growth in vivo (P < .01). MiR429 was a mediator of circ_0008035 function, and miR-429 hindered GC cell malignant phenotypes by SMAD2. Circ_0008035 aggravates GC cell malignant progression partially by targeting the miR-429/SMAD2 axis. Considering the inhibitory effect of circ_0008035 deficiency on GC progression, targeting circ_0008035 may be a potential approach to prevent or treat GC.

GABA Type A receptors expressed in triple negative breast cancer cells mediate chloride ion flux.

Triple negative breast cancer (TNBC) is known for its heterogeneous nature and aggressive onset, limited unresponsiveness to hormone therapies and immunotherapy as well as high likelihood of metastasis and recurrence. Since no targeted standard treatment options are available for TNBC, novel and effective therapeutic targets are urgently needed. Ion channels have emerged as possible novel therapeutic candidates for cancer therapy. We previously showed that GABAA β3 subunit are expressed at higher levels in TNBC cell lines than non-tumorigenic MCF10A cells. GABAA β3 subunit knockdown causes cell cycle arrest in TNBC cell lines via decreased cyclin D1 and increased p21 expression. However, it is not known if the upregulated GABAAR express at the cell-surface in TNBC and mediate Cl- flux. Cl- ions are known to play a role in cell-cycle progression in other cancers such as gastric cancer. Here, using surface biotinylation and (N-(Ethoxycarbonylmethyl)-6-Methoxyquinolinium Bromide) MQAE-dye based fluorescence quenching, we show that upregulated GABAAR are on the cell-surface in TNBC cell lines and mediate significantly higher chloride (Cl-) flux as compared to non-tumorigenic MCF10A cells. Moreover, this GABAAR mediated Cl- flux can be modulated by pharmacological agents and is decreased in TNBC cells with GABAA β3 subunit knockdown. Further, treatment of TNBC cells with bicuculline, a GABAAR antagonist reduced cell viability in TNBC cells Overall, these results point to an unexplored role of GABAAR mediated Cl- flux in TNBC.

Polo-like Kinase 1 Predicts Lymph Node Metastasis in Middle Eastern Colorectal Cancer Patients; Its Inhibition Reverses 5-Fu Resistance in Colorectal Cancer Cells.

Polo-like kinase 1 (PLK1) is a serine/threonine-protein kinase essential for regulating multiple stages of cell cycle progression in mammals. Aberrant regulation of PLK1 has been observed in numerous human cancers and is linked to poor prognoses. However, its role in the pathogenesis of colorectal cancer (CRC) in the Middle East remains unexplored. PLK1 overexpression was noted in 60.3% (693/1149) of CRC cases and was significantly associated with aggressive clinico-pathological parameters and p-ERK1/2 overexpression. Intriguingly, multivariate logistic regression analysis identified PLK1 as an independent predictor of lymph node metastasis. Our in vitro experiments demonstrated that CRC cells with high PLK1 levels were resistant to 5-Fu treatment, while those with low PLK1 expression were sensitive. To investigate PLK1's role in chemoresistance, we used the specific inhibitor volasertib, which effectively reversed 5-Fu resistance. Interestingly, forced PLK1 expression activated the CRAF-MEK-ERK signaling cascade, while its inhibition suppressed this cascade. PLK1 knockdown reduced epithelial-to-mesenchymal transition (EMT) progression and stem cell-like traits in 5-Fu-resistant cells, implicating PLK1 in EMT induction and stemness in CRC. Moreover, silencing ERK1/2 significantly mitigated chemoresistance, EMT, and stemness properties in CRC cell lines that express PLK1. Furthermore, the knockdown of Zeb1 attenuated EMT and stemness, suggesting a possible link between EMT activation and the maintenance of stemness in CRC. Our findings underscore the pivotal role of PLK1 in mediating chemoresistance and suggest that PLK1 inhibition may represent a potential therapeutic strategy for the management of aggressive colorectal cancer subtypes.

PIWIL1 is recruited to centrosomes during mitosis in colorectal cancer cells and is linked to cell cycle progression

PIWI proteins, traditionally associated with germline development, have recently gained attention for their expression in various cancers, including colorectal cancer. However, the molecular mechanisms underlying their reactivation and impact on cancer initiation and progression remain elusive. Here, we found that PIWIL1 is expressed at relatively high levels in CRC-derived samples and cell lines, where it undergoes a dynamic relocalization to the centrosome during mitosis. Knockdown of PIWIL1 induces G2/M arrest associated with disruption of the mitotic spindle and aberrant metaphase events, highlighting its role in cell cycle progression. We also found that the expression of PIWIL1 is lost during the differentiation of Caco-2 cells into enterocytes and that PIWIL1 is expressed in cells at the base of the intestinal crypts in normal human colon tissue, where intestinal stem cells are known to reside. Thus, it is possible that the presence of PIWIL1 in cancer cells reflects a physiological role of this protein in stem cell maintenance, which would argue in favor of the proposed stem cell origin of CRC. Supporting this view, dedifferentiation of human fibroblasts into induced pluripotent stem cells (iPSCs) involves the reactivation of PIWIL2 expression, another member of the PIWI protein family. Overall, our findings suggest a role of PIWIL1 in mediating cell cycle dynamics, both in colorectal cancer cells and possibly also in intestinal stem cells. In a broader aspect, we provide evidence supporting an involvement of PIWI proteins in somatic stem cell maintenance, thus expanding the known non-gonadal functions of this protein family.

Polyploidy mitigates the impact of DNA damage while simultaneously bearing its burden

Polyploidy is frequently enhanced under pathological conditions, such as tissue injury and cancer in humans. Polyploidization is critically involved in cancer evolution, including cancer initiation and the acquisition of drug resistance. However, the effect of polyploidy on cell fate remains unclear. In this study, we explored the effects of polyploidization on cellular responses to DNA damage and cell cycle progression. Through various comparisons based on ploidy stratifications of cultured cells, we found that polyploidization and the accumulation of genomic DNA damage mutually induce each other, resulting in polyploid cells consistently containing more genomic DNA damage than diploid cells under both physiological and stress conditions. Notably, despite substantial DNA damage, polyploid cells demonstrated a higher tolerance to its impact, exhibiting delayed cell cycle arrest and reduced secretion of inflammatory cytokines associated with DNA damage-induced senescence. Consistently, in mice with ploidy tracing, hepatocytes with high ploidy appeared to potentially persist in the damaged liver, while being susceptible to DNA damage. Polyploidy acts as a reservoir of genomic damage by mitigating the impact of DNA damage, while simultaneously enhancing its accumulation.

Differential regulation of expression of the protein kinases DYRK1A and DYRK1B in cancer cells

The protein kinases DYRK1A and DYRK1B are pivotal regulators of cell cycle progression by promoting cell cycle exit into quiescence. DYRK1B appears to play a more important role in cancer cell quiescence than DYRK1A, as evidenced by its overexpression or copy number variations in human tumour samples. Nonetheless, the stimuli driving DYRK1B upregulation and the potential divergence in expression patterns between DYRK1A and DYRK1B remain largely elusive. In the present study, we scrutinized the regulatory pathways modulating DYRK1B expression relative to DYRK1A in PANC-1 and A549 cancer cell lines across varying conditions. Serum deprivation, pharmacological mTOR inhibition and increased cell density resulted in the differential upregulation of DYRK1B compared to DYRK1A. We then aimed to assess the role of protein kinases MST1 and MST2, which are key transmitters of cell density dependent effects. Unexpectedly, exposure to the MST1/2 inhibitor XMU-MP-1 resulted in increased DYRK1B levels in A549 cells. Further investigation into the off-target effects of XMU-MP-1 unveiled the inhibition of Aurora kinases (AURKA and AURKB) as a potential causative factor. Consistently, AURK inhibitors VX-680 (tozasertib), MLN8237 (alisertib), AZD1152-HQPA (barasertib) resulted in the upregulation of DYRK1B expression in A549 cells. In summary, our findings indicate that the expression of DYRK1A and DYRK1B is differentially regulated in cancer cells and reveal that the kinase inhibitor XMU-MP-1 increases DYRK1B expression likely through off target inhibition of Aurora kinases.

SLC30A2-Mediated Zinc Metabolism Modulates Gastric Cancer Progression via the Wnt/β-Catenin Signaling Pathway.

Gastric cancer (GC) is a significant global health burden with limited treatment options. The purpose of this study was to investigate the role of SLC30A2, a zinc transporter, in GC development and its capacity as a target for therapy. A comprehensive analysis of GC datasets (GSE54129 and stomach adenocarcinoma (STAD) from The Cancer Genome Atlas (TCGA)) was conducted using bioinformatics tools to examine differential gene expression, focusing on SLC30A2. Functional assays, including Cell counting kit-8 (CCK-8) and transwell assays, were carried out on GC cell lines to determine the impact of SLC30A2 knockdown on cell behavior. Flow cytometry was utilized to quantitatively observe cell apoptosis and cell cycle progression. The impact of zinc sulfate (ZnSO4) on GC cells was evaluated by detecting apoptosis markers, Wnt/β-catenin signaling pathway activity, and oxidative stress biomarkers, focusing on the regulatory effect of SLC30A2 overexpression. Our analysis revealed significant upregulation of SLC30A2 in GC samples compared to normal samples, and high SLC30A2 expression was linked to poor prognosis. SLC30A2 knockdown repressed proliferation, invasion, and migration of GC cells, induced apoptosis, as well as arrested the cell cycle. Additionally, ZnSO4 treatment induced cytotoxicity and oxidative stress in GC cells, while SLC30A2 overexpression rescued ZnSO4-induced, migration, invasion, and proliferation. Moreover, ZnSO4 had been shown to bolster apoptosis and trigger the Wnt/β-catenin signaling pathway, effects which were mitigated by the overexpression of SLC30A2. Our results implied that SLC30A2 was essential for GC progression by modulating zinc homeostasis and cellular processes. Targeting SLC30A2 or zinc signaling may represent a potential therapeutic approach for GC treatment.

Novel dual inhibitor targeting CDC25 and HDAC for treating triple-negative breast cancer

Triple-negative breast cancer (TNBC) presents a significant challenge for treatment due to its aggressive nature and the lack of effective therapies. This study developed dual inhibitors against cell division cycle 25 (CDC25) and histone deacetylases (HDACs) for TNBC treatment. CDC25 phosphatases are crucial for activating cyclin-dependent kinases (CDKs), the master regulators of cell cycle progression. HDACs regulate various biological processes by deacetylating histone and non-histone proteins, affecting gene expression, chromatin structure, cell differentiation, and proliferation. Dysregulations of HDAC and CDC25 are associated with several human malignancies. We generated a group of dual inhibitors for CDC25 and HDAC by combining the molecular structures of CDC25 (quinoline-5,8-dione) and HDAC (hydroxamic acid or benzamide) pharmacophores. The newly developed compounds were evaluated against various solid-tumor, leukemia, and non-malignant breast epithelial cells. Among the synthesized compounds, 18A emerged as a potent inhibitor, demonstrating significant cytotoxicity against TNBC cells, superior to its effects on other cancer types while sparing non-malignant cells. 18A possessed similar HDAC inhibitory activity as MS-275 and potently suppressed CDC25 activity in vitro and the CDK1 dephosphorylation in cells. Additionally, 18A hindered the progression of S and G2/M phases, triggered DNA damage, and induced apoptosis. These findings underscore the potential of 18A as a targeted therapy for TNBC and warrants further preclinical development.Graphical

Cell cycle checkpoint revolution: targeted therapies in the fight against malignant tumors.

Malignant tumors are among the most important causes of death worldwide. The pathogenesis of a malignant tumor is complex and has not been fully elucidated. Studies have shown that such pathogenesis is related to abnormal cell cycle progression. The expression levels of cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors as well as functions of the cell cycle checkpoints determine whether the cell cycle progression is smooth. Cell-cycle-targeting drugs have the advantages of high specificity, low toxicity, low side effects, and low drug resistance. Identifying drugs that target the cell cycle and applying them in clinical treatments are expected to promote chemotherapeutic developments against malignant tumors. This article aims to review drugs targeted against the cell cycle and their action mechanisms.

Transcriptional inhibition after irradiation occurs preferentially at highly expressed genes in a manner dependent on cell cycle progression

In response to DNA double-strand damage, ongoing transcription is inhibited to facilitate accurate DNA repair while transcriptional recovery occurs after DNA repair is complete. However, the mechanisms at play and the identity of the transcripts being regulated in this manner are unclear. In contrast to the situation following UV damage, we found that transcriptional recovery after ionizing radiation (IR) occurs in a manner independent of the HIRA histone chaperone. Sequencing of the nascent transcripts identified a programmed transcriptional response, where certain transcripts and pathways are rapidly downregulated after IR, while other transcripts and pathways are upregulated. Specifically, most of the loss of nascent transcripts occurring after IR is due to inhibition of transcriptional initiation of the highly transcribed histone genes and the rDNA. To identify factors responsible for transcriptional inhibition after IR in an unbiased manner, we performed a whole genome gRNA library CRISPR/Cas9 screen. Many of the top hits on our screen were factors required for protein neddylation. However, at short times after inhibition of neddylation, transcriptional inhibition still occurred after IR, even though neddylation was effectively inhibited. Persistent inhibition of neddylation blocked transcriptional inhibition after IR, and it also leads to cell cycle arrest. Indeed, we uncovered that many inhibitors and conditions that lead to cell cycle arrest in G1 or G2 phase also prevent transcriptional inhibition after IR. As such, it appears that transcriptional inhibition after IR occurs preferentially at highly expressed genes in cycling cells.

Transcriptional inhibition after irradiation occurs preferentially at highly expressed genes in a manner dependent on cell cycle progression.

In response to DNA double-strand damage, ongoing transcription is inhibited to facilitate accurate DNA repair while transcriptional recovery occurs after DNA repair is complete. However, the mechanisms at play and the identity of the transcripts being regulated in this manner are unclear. In contrast to the situation following UV damage, we found that transcriptional recovery after ionizing radiation (IR) occurs in a manner independent of the HIRA histone chaperone. Sequencing of the nascent transcripts identified a programmed transcriptional response, where certain transcripts and pathways are rapidly downregulated after IR, while other transcripts and pathways are upregulated. Specifically, most of the loss of nascent transcripts occurring after IR is due to inhibition of transcriptional initiation of the highly transcribed histone genes and the rDNA. To identify factors responsible for transcriptional inhibition after IR in an unbiased manner, we performed a whole genome gRNA library CRISPR/Cas9 screen. Many of the top hits on our screen were factors required for protein neddylation. However, at short times after inhibition of neddylation, transcriptional inhibition still occurred after IR, even though neddylation was effectively inhibited. Persistent inhibition of neddylation blocked transcriptional inhibition after IR, and it also leads to cell cycle arrest. Indeed, we uncovered that many inhibitors and conditions that lead to cell cycle arrest in G1 or G2 phase also prevent transcriptional inhibition after IR. As such, it appears that transcriptional inhibition after IR occurs preferentially at highly expressed genes in cycling cells.