m6A modification enhances the stability of CDC25A promotes tumorigenicity of esophagogastric junction adenocarcinoma via cell cycle.

N6-Methyladenosine (m6A) modification and its regulators play critical roles in human cancers, but their functions and regulatory mechanisms in adenocarcinoma of the esophagogastric junction (AEG) remain unclear. Here, we identified that IGF2BP3 is the most significantly up-regulated m6A regulator in AEG tumors versus paired normal adjacent tissues from the expression profile of m6A regulators in a large cohort of AEG patients. Silencing IGF2BP3 inhibits AEG progression in vitro and in vivo. By profiling transcriptome-wide targets of IGF2BP3 and the m6A methylome in AEG, we found that IGF2BP3-mediated stabilization and enhanced expression of m6A-modified targets, including targets of the cell cycle pathway, such as CDC25A, CDK4, and E2F1, are critical for AEG progression. Mechanistically, the increased m6A modification of CDC25A accelerates the G1-S transition. Clinically, up-regulated IGF2BP3, METTL3, and CDC25A show a strong positive correlation in TCGA pan-cancer, including AEG. In conclusion, our study highlights the role of post-transcriptional regulation in modulating AEG tumor progression and elucidates the functional importance of the m6A/IGF2BP3/CDC25A axis in AEG cells.

miR-449a mediated repression of the cell cycle machinery prevents neuronal apoptosis.

Aberrant activation of the cell cycle of terminally differentiated neurons results in their apoptosis and is known to contribute to neuronal loss in various neurodegenerative disorders like Alzheimer's Disease. However, the mechanisms that regulate cell cycle-related neuronal apoptosis are poorly understood. We identified several miRNA that are dysregulated in neurons from a transgenic APP/PS1 mouse model for AD (TgAD). Several of these miRNA are known to and/or are predicted to target cell cycle-related genes. Detailed investigation on miR-449a revealed the following: a, it promotes neuronal differentiation by suppressing the neuronal cell cycle; b, its expression in cortical neurons was impaired in response to amyloid peptide Aß42; c, loss of its expression resulted in aberrant activation of the cell cycle leading to apoptosis. miR-449a may prevent cell cycle-related neuronal apoptosis by targeting cyclin D1 and protein phosphatase CDC25A, which are important for G1-S transition. Importantly, the lentiviral-mediated delivery of miR-449a in TgAD mouse brain significantly reverted the defects in learning and memory, which are associated with AD.

Reynoutria multiflora (Thunb.) Moldenke and its ingredient suppress lethal prostate cancer growth by inducing CDC25B-CDK1 mediated cell cycle arrest.

BACKGROUND: Reynoutria multiflora (Thunb.) Moldenke (Polygonum multiflorum Thunb, PM) is a medicinal plant that was an element of traditional Chinese medicine (TCM) for centuries as a treatment for a wide range of conditions. Recent studies reported that PM suppressed prostate cancer growth in an AR-dependent manner. However, its role and mechanism in the treatment of advanced prostate cancer remain to be explored. This study aims to explore the anti-tumor role and potential mechanism of PM on prostate cancer. METHODS: Cell viability, colony formation, fluorescence-activated cell sorting (FACS), and wound-healing assays were conducted to evaluate the tumor suppression effect of PM on lethal prostate cancer models in vitro. A xenograft mice model was established to detect the impact of PM on tumor growth and evaluate its biosafety in vivo. Integrative network pharmacology, RNA-seq, and bioinformatics were applied to determine the mechanisms of PM in prostate cancer. Molecular docking, cellular thermal shift assay (CETSA), CRISPR-Cas13, RT-qPCR, and WB were collaboratively employed to identify the potential anti-tumor ingredient derived from PM and its corresponding targets. RESULTS: PM significantly suppressed the growth of prostate cancer and sensitized prostate cancer to AR antagonists. Mechanistically, PM induced G2/M-phase cell-cycle arrest by modulating the phosphorylation of CDK1. Additionally, polygalacic acid derived from PM and its structural analog suppress prostate cancer growth by targeting CDC25B, a master regulator of the cell cycle that governs CDK1 phosphorylation. CONCLUSION: PM and its ingredient polygalacic acid suppress lethal prostate cancer growth by regulating the CDC25B-CDK1 axis to induce cell cycle arrest.

ß,ß-Dimethylacrylalkannin, a key component of Zicao, induces cell cycle arrest and necrosis in hepatocellular carcinoma cells.

BACKGROUND: ß,ß-Dimethylacrylalkannin (DMAKN), a natural naphthoquinone found in Zicao, a traditional Chinese medicine (TCM), serves as the designated quantitative marker in the Chinese Pharmacopoeia. Despite its established role in assessing Zicao quality, DMAKN's biological potential remains underexplored in research. METHODS: We investigated DMAKN's involvement in Zicao's anti-hepatocellular carcinoma (HCC) properties using a combination of HPLC content analysis and comprehensive bioinformatics. Subsequently, both in vitro and in vivo experiments were conducted to evaluate DMAKN's efficacy against HCC. Mechanistic investigations focused on elucidating DMAKN's impact on cell cycle regulation and induction of cell death. RESULTS: Integrated HPLC analysis and bioinformatics identified DMAKN as the primary active compound responsible for Zicao's anti-HCC activity. In vitro and in vivo studies confirmed DMAKN's potent efficacy against HCC. Notably, DMAKN demonstrated dual effects on HCC cells: inhibiting proliferation at lower doses and inducing rapid cell death at higher doses. Mechanistic insights revealed that low-dose DMAKN induced G2/M phase cell cycle arrest through modulation of CDK1 and Cdc25C phosphorylation, while high-dose DMAKN triggered necrosis. Importantly, high-dose DMAKN caused a sharp increase in intracellular ROS levels in a short time, while low-dose DMAKN gradually increased ROS levels over a long period. Additionally, low-dose DMAKN-induced ROS activated the JNK pathway, crucial for cell cycle arrest, whereas high-dose DMAKN-induced necrosis was ROS-dependent but JNK-independent. CONCLUSION: This study underscores DMAKN's pivotal role as the principal anti-HCC compound in Zicao, delineating its differential effects and underlying mechanisms. These results demonstrate the potential of DMAKN as a therapeutic agent for the treatment of HCC, providing important information for further study and advancement in cancer therapy.

Cryo-EM structure of the CDK2-cyclin A-CDC25A complex.

The cell division cycle 25 phosphatases CDC25A, B and C regulate cell cycle transitions by dephosphorylating residues in the conserved glycine-rich loop of CDKs to activate their activity. Here, we present the cryo-EM structure of CDK2-cyclin A in complex with CDC25A at 2.7 Å resolution, providing a detailed structural analysis of the overall complex architecture and key protein-protein interactions that underpin this 86 kDa complex. We further identify a CDC25A C-terminal helix that is critical for complex formation. Sequence conservation analysis suggests CDK1/2-cyclin A, CDK1-cyclin B and CDK2/3-cyclin E are suitable binding partners for CDC25A, whilst CDK4/6-cyclin D complexes appear unlikely substrates. A comparative structural analysis of CDK-containing complexes also confirms the functional importance of the conserved CDK1/2 GDSEID motif. This structure improves our understanding of the roles of CDC25 phosphatases in CDK regulation and may inform the development of CDC25-targeting anticancer strategies.

A novel selenium analog of HDACi-based twin drug induces apoptosis and cell cycle arrest via CDC25A to improve prostate cancer therapy.

Cancer therapy has moved from single agents to more mechanism-based targeted approaches. In recent years, the combination of HDAC inhibitors and other anticancer chemicals has produced exciting progress in cancer treatment. Herein, we developed a novel prodrug via the ligation of dichloroacetate to selenium-containing potent HDAC inhibitors. The effect and mechanism of this compound in the treatment of prostate cancer were also studied. Methods: The concerned prodrug SeSA-DCA was designed and synthesized under mild conditions. This compound's preclinical studies, including the pharmacokinetics, cell toxicity, and anti-tumor effect on prostate cancer cell lines, were thoroughly investigated, and its possible synergistic mechanism was also explored and discussed. Results: SeSA-DCA showed good stability in physiological conditions and could be rapidly decomposed into DCA and selenium analog of SAHA (SeSAHA) in the tumor microenvironment. CCK-8 experiments identified that SeSA-DCA could effectively inhibit the proliferation of a variety of tumor cell lines, especially in prostate cancer. In further studies, we found that SeSA-DCA could also inhibit the metastasis of prostate cancer cell lines and promote cell apoptosis. At the animal level, oral administration of SeSA-DCA led to significant tumor regression without obvious toxicity. Moreover, as a bimolecular coupling compound, SeSA-DCA exhibited vastly superior efficacy than the mixture with equimolar SeSAHA and DCA both in vitro and in vivo. Our findings provide an important theoretical basis for clinical prostate cancer treatment. Conclusions: Our in vivo and in vitro results showed that SeSA-DCA is a highly effective anti-tumor compound for PCa. It can effectively induce cell cycle arrest and growth suppression and inhibit the migration and metastasis of PCa cell lines compared with monotherapy. SeSA-DCA's ability to decrease the growth of xenografts is a little better than that of docetaxel without any apparent signs of toxicity. Our findings provide an important theoretical basis for clinical prostate cancer treatment.

Fangchinoline inhibits mouse oocyte meiosis by disturbing MPF activity.

Fangchinoline (FA) is an alkaloid derived from the traditional Chinese medicine Fangji. Numerous studies have shown that FA has a toxic effect on various cancer cells, but little is known about its toxic effects on germ cells, especially oocytes. In this study, we investigated the effects of FA on mouse oocyte maturation and its potential mechanisms. Our results showed that FA did not affect meiosis resumption but inhibited the first polar body extrusion. This inhibition is not due to abnormalities at the organelle level, such as chromosomes and mitochondrial, which was proved by detection of DNA damage and reactive oxygen species. Further studies revealed that FA arrested the oocyte at the metaphase I stage, and this arrest was not caused by abnormal kinetochore-microtubule attachment or spindle assembly checkpoint activation. Instead, FA inhibits the activity of anaphase-promoting complexes (APC/C), as evidenced by the inhibition of CCNB1 degeneration. The decreased activity of APC/C may be due to a reduction in CDC25B activity as indicated by the high phosphorylation level of CDC25B (Ser323). This may further enhance Maturation-Promoting Factor (MPF) activity, which plays a critical role in meiosis. In conclusion, our study suggests that the metaphase I arrest caused by FA may be due to abnormalities in MPF and APC/C activity.

Inhibition of Melanoma Cell Growth by Salvianolic Acid A through CHK2-CDC25A Pathway Modulation.

BACKGROUND: This study investigated the impact of salvianolic acids, derived from Danshen, on melanoma cell growth. Specifically, we assessed the ability of salvianolic acid A (Sal A) to modulate melanoma cell proliferation. METHODS: We used human melanoma A2058 and A375 cell lines to investigate the effects of Sal A on cell proliferation and death by measuring bromodeoxyuridine incorporation and lactate dehydrogenase release. We assessed cell viability and cycle progression using water soluble tetrazolium salt-1 (WST-1) mitochondrial staining and propidium iodide. Additionally, we used a phospho-kinase array to investigate intracellular kinase phosphorylation, specifically measuring the influence of Sal A on checkpoint kinase-2 (Chk-2) via western blot analysis. RESULTS: Sal A inhibited the growth of A2058 and A375 cells dose-responsively and induced cell cycle arrest at the G2/M phase. Notably, Sal A selectively induces Chk-2 phosphorylation without affecting Chk-1, thereby degrading Chk-2-regulated genes Cdc25A and Cdc2. However, Sal A does not affect the Chk1-Cdc25C pathway. CONCLUSIONS: Salvianolic acids, especially Sal A, effectively hinder melanoma cell growth by inducing Chk-2 phosphorylation and disrupting G2/M checkpoint regulation.

PEMF Potentiates Doxorubicin-induced Late G2 Arrest in MDA-MB-231 Breast Cancer Cells.

BACKGROUND/AIM: Pulsed electromagnetic field (PEMF) stimulation enhances the efficacy of several anticancer drugs. Doxorubicin is an anticancer drug used to treat various types of cancer, including breast cancer. However, the effect of PEMF stimulation on the efficacy of doxorubicin and the underlying mechanisms remain unclear. Thus, this study aimed to investigate the effect of PEMF stimulation on the anticancer activity of doxorubicin in MDA-MB-231 human breast cancer cells. MATERIALS AND METHODS: MDA-MB-231 cells were seeded and allowed to incubate for 48 h. The cells were treated with doxorubicin, cisplatin, 5-fluorouracil, or paclitaxel for 48 h. Subsequently, the cells were stimulated with a 60-min PEMF session thrice a day (with an interval of 4 h between each session) for 24 or 48 h. Cell viability was assessed by trypan blue dye exclusion assay and cell-cycle analysis was analyzed by flow cytometry. Molecular mechanisms involved in late G2 arrest were confirmed by a western blot assay and confocal microscopy. RESULTS: MDA-MB-231 cells treated with a combination of doxorubicin and PEMF had remarkably lower viability than those treated with doxorubicin alone. PEMF stimulation increased doxorubicin-induced cell-cycle arrest in the late G2 phase by suppressing cyclin-dependent kinase 1 (CDK1) activity through the enhancement of myelin transcription factor 1 (MYT1) expression, cell division cycle 25C (CDC25C) phosphorylation, and stratifin (14-3-3σ) expression. PEMF also increased doxorubicin-induced DNA damage by inhibiting DNA topoisomerase II alpha (TOP2A). CONCLUSION: These findings support the use of PEMF stimulation as an adjuvant to strengthen the antiproliferative effect of doxorubicin on breast cancer cells.

Cell division cyclin 25C knockdown inhibits hepatocellular carcinoma development by inducing endoplasmic reticulum stress.

BACKGROUND: Cell division cyclin 25C (CDC25C) is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research has shown that CDC25C could be a potential therapeutic target for cancers, particularly for hepatocellular carcinoma (HCC). However, the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood. AIM: To explore the impact of CDC25C on cell proliferation and apoptosis, as well as its regulatory mechanisms in HCC development. METHODS: Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences (LV-CDC25C shRNA) to knock down CDC25C. Subsequently, a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo. Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays, respectively. The expression of endoplasmic reticulum (ER) stress-related molecules (glucose-regulated protein 78, X-box binding protein-1, and C/EBP homologous protein) was measured in both cells and subcutaneous xenografts using quantitative real-time PCR (qRT-PCR) and western blotting. Additionally, apoptosis was investigated using flow cytometry, qRT-PCR, and western blotting. RESULTS: CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction. A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice. CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response, ultimately promoting ER stress-induced apoptosis in HCC cells. CONCLUSION: The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.

The Development of CDC25A-Derived Phosphoseryl Peptides That Bind 14-3-3ε with High Affinities.

Overexpression of the 14-3-3ε protein is associated with suppression of apoptosis in cutaneous squamous cell carcinoma (cSCC). This antiapoptotic activity of 14-3-3ε is dependent on its binding to CDC25A; thus, inhibiting 14-3-3ε - CDC25A interaction is an attractive therapeutic approach to promote apoptosis in cSCC. In this regard, designing peptide inhibitors of 14-3-3ε - CDC25A interactions is of great interest. This work reports the rational design of peptide analogs of pS, a CDC25A-derived peptide that has been shown to inhibit 14-3-3ε-CDC25A interaction and promote apoptosis in cSCC with micromolar IC50. We designed new peptide analogs in silico by shortening the parent pS peptide from 14 to 9 amino acid residues; then, based on binding motifs of 14-3-3 proteins, we introduced modifications in the pS(174-182) peptide. We studied the binding of the peptides using conventional molecular dynamics (MD) and steered MD simulations, as well as biophysical methods. Our results showed that shortening the pS peptide from 14 to 9 amino acids reduced the affinity of the peptide. However, substituting Gln176 with either Phe or Tyr amino acids rescued the binding of the peptide. The optimized peptides obtained in this work can be candidates for inhibition of 14-3-3ε - CDC25A interactions in cSCC.

KIF22 promotes multiple myeloma progression by regulating the CDC25C/CDK1/cyclinB1 pathway.

PURPOSE: Multiple myeloma (MM) is an incurable hematological malignancy characterized by clonal proliferation of malignant plasma B cells in bone marrow, and its pathogenesis remains unknown. The aim of this study was to determine the role of kinesin family member 22 (KIF22) in MM and elucidate its molecular mechanism. METHODS: The expression of KIF22 was detected in MM patients based upon the public datasets and clinical samples. Then, in vitro assays were performed to investigate the biological function of KIF22 in MM cell lines, and subcutaneous xenograft models in nude mice were conducted in vivo. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay were used to determine the mechanism of KIF22-mediated regulation. RESULTS: The results demonstrated that the expression of KIF22 in MM patients was associated with several clinical features, including gender (P = 0.016), LDH (P < 0.001), ß2-MG (P = 0.003), percentage of tumor cells (BM) (P = 0.002) and poor prognosis (P < 0.0001). Furthermore, changing the expression of KIF22 mainly influenced the cell proliferation in vitro and tumor growth in vivo, and caused G2/M phase cell cycle dysfunction. Mechanically, KIF22 directly transcriptionally regulated cell division cycle 25C (CDC25C) by binding its promoter and indirectly influenced CDC25C expression by regulating the ERK pathway. KIF22 also regulated CDC25C/CDK1/cyclinB1 pathway. CONCLUSION: KIF22 could promote cell proliferation and cell cycle progression by transcriptionally regulating CDC25C and its downstream CDC25C/CDK1/cyclinB1 pathway to facilitate MM progression, which might be a potential therapeutic target in MM.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq reveals immune suppression subtypes and establishes a novel signature for determining the prognosis in lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most common histological type of lung cancer with lower survival rates. Recent advancements in targeted therapies and immunotherapies targeting immune checkpoints have achieved remarkable success, there is still a large percentage of LUAD that lacks available therapeutic options. Due to tumor heterogeneity, the diagnosis and treatment of LUAD are challenging. Exploring the biology of LUAD and identifying new biomarker and therapeutic targets options are essential. METHOD: We performed single-cell RNA sequencing (scRNA-seq) of 6 paired primary and adjacent LUAD tissues, and integrative omics analysis of the scRNA-seq, bulk RNA-seq and whole-exome sequencing data revealed molecular subtype characteristics. Our experimental results confirm that CDC25C gene can serve as a potential marker for poor prognosis in LUAD. RESULTS: We investigated aberrant gene expression in diverse cell types in LUAD via the scRNA-seq data. Moreover, multi-omics clustering revealed four subgroups defined by transcriptional profile and molecular subtype 4 (MS4) with poor survival probability, and immune cell infiltration signatures revealed that MS4 tended to be the immunosuppressive subtype. Our study revealed that the CDC25C gene can be a distinct prognostic biomarker that indicates immune infiltration levels and response to immunotherapy in LUAD patients. Our experimental results concluded that CDC25C expression affects lung cancer cell invasion and migration, might play a key role in regulating Epithelial-Mesenchymal Transition (EMT) pathways. CONCLUSIONS: Our multi-omics result revealed a comprehensive set of molecular attributes associated with prognosis-related genes in LUAD at the cellular and tissue level. Identification of a subtype of immunosuppressive TME and prognostic signature for LUAD. We identified the cell cycle regulation gene CDC25C affects lung cancer cell invasion and migration, which can be used as a potential biomarker for LUAD.

A multicenter, randomized phase 2 study to establish combinations of CBP501, cisplatin and nivolumab for ≥3rd-line treatment of patients with advanced pancreatic adenocarcinoma.

BACKGROUND: There is no standard of care for ≥ 3rd-line treatment of metastatic pancreatic adenocarcinoma (PDAC). CBP501 is a novel calmodulin-binding peptide that has been shown to enhance the influx of platinum agents into tumor cells and tumor immunogenicity. This study aimed to (1) confirm efficacy of CBP501/cisplatin/nivolumab for metastatic PDAC observed in a previous phase 1 study, (2) identify combinations that yield 35% 3-month progression-free survival rate (3MPFS) and (3) define the contribution of CBP501 to the effects of combination therapy. METHODS: CBP501 16 or 25 mg/m2 (CBP(16) or CBP(25)) was combined with 60 mg/m2 cisplatin (CDDP) and 240 mg nivolumab (nivo), administered at 3-week intervals. Patients were randomized 1:1:1:1 to (1) CBP(25)/CDDP/nivo, (2) CBP(16)/CDDP/nivo, (3) CBP(25)/CDDP and (4) CDDP/nivo, with randomization stratified by ECOG PS and liver metastases. A Fleming two-stage design was used, yielding a one-sided type I error rate of 2.5% and 80% power when the true 3MPFS is 35%. RESULTS: Among 36 patients, 3MPFS was 44.4% in arms 1 and 2, 11.1% in arm 3% and 33.3% in arm 4. Two patients achieved a partial response in arm 1 (ORR 22.2%; none in other arms). Median PFS and OS were 2.4, 2.1, 1.5 and 1.5 months and 6.3, 5.3, 3.7 and 4.9 months, respectively. Overall, all treatment combinations were well tolerated. Most treatment-related adverse events were grade 1-2. CONCLUSIONS: The combination CBP(25)/(16)/CDDP/nivo demonstrated promising signs of efficacy and a manageable safety profile for the treatment of advanced PDAC. CLINICAL TRIAL REGISTRATION: NCT04953962.

Yifei Sanjie formula alleviates lung cancer progression via regulating PRMT6-YBX1-CDC25A axis.

Lung cancer (LC) is the most prevalent cancer type, with a high mortality rate worldwide. The current treatment options for LC have not been particularly successful in improving patient outcomes. Yifei Sanjie (YFSJ), a well-applicated traditional Chinese medicine formula, is widely used to treat pulmonary diseases, especially LC, yet little is known about its molecular mechanisms. This study was conducted to explore the molecular mechanism by which YFSJ ameliorated LC progression. The A549, NCI-H1975, and Calu-3 cells were treated with the YFSJ formula and observed for colony number, apoptosis, migration, and invasion properties recorded via corresponding assays. The PRMT6-YBX1-CDC25A axis was tested and verified through luciferase reporter, RNA immunoprecipitation, and chromatin immunoprecipitation assays and rescue experiments. Our results demonstrated that YFSJ ameliorated LC cell malignant behaviors by increasing apoptosis and suppressing proliferation, migration, and invasion processes. We also noticed that the xenograft mouse model treated with YFSJ significantly reduced tumor growth compared with the control untreated group in vivo. Mechanistically, it was found that YFSJ suppressed the expression of PRMT6, YBX1, and CDC25A, while the knockdown of these proteins significantly inhibited colony growth, migration, and invasion, and boosted apoptosis in LC cells. In summary, our results suggest that YFSJ alleviates LC progression via the PRMT6-YBX1-CDC25A axis, confirming its efficacy in clinical use. The findings of our study provide a new regulatory network for LC growth and metastasis, which could shed new insights into pulmonary medical research.

Transcription factor E2F3 activates CDC25B to regulate DNA damage and promote mitoxantrone resistance in stomach adenocarcinoma.

BACKGROUND: CDC25B, as a member of the cell cycle regulating protein family, is located in the cytoplasm and is involved in the transition of the cell cycle and mitosis. CDC25B is highly expressed in various tumors and is a newly discovered oncogene. This study aimed to investigate the impact of CDC25B on mitoxantrone resistance in stomach adenocarcinoma (STAD) and its possible mechanisms. METHODS: This study analyzed the expression of CDC25B and its potential transcription factor E2F3 in STAD, as well as the IC50 values of tumor tissues by bioinformatics analysis. Expression levels of CDC25B and E2F3 in STAD cells were measured by qRT-PCR. MTT was utilized to evaluate cell viability and IC50 values of STAD cells, and comet assay was utilized to analyze the level of DNA damage in STAD cells. Western blot was used to analyze the expression of DNA damage-related proteins. The targeting relationship between E2F3 and CDC25B was validated by dual-luciferase and ChIP assays. RESULTS: Bioinformatics analysis and molecular experiments showed that CDC25B and E2F3 were highly expressed in STAD, and CDC25B was enriched in the mismatch repair and nucleotide excision repair pathways. The IC50 values of tumor tissues with high expression of CDC25B were relatively high. Dual-luciferase and ChIP assays confirmed that CDC25B could be transcriptionally activated by E2F3. Cell experiments revealed that CDC25B promoted mitoxantrone resistance in STAD cells by regulating DNA damage. Further research found that low expression of E2F3 inhibited mitoxantrone resistance in STAD cells by DNA damage, but overexpression of CDC25B reversed the impact of E2F3 knockdown on mitoxantrone resistance in STAD cells. CONCLUSION: This study confirmed a novel mechanism by which E2F3/CDC25B mediated DNA damage to promote mitoxantrone resistance in STAD cells, providing a new therapeutic target for STAD treatment.

ERß-activated LINC01018 promotes endometriosis development by regulating the CDC25C/CDK1/CyclinB1 pathway.

Endometriosis refers to as an estrogen-dependent disease. Estrogen receptor ß (ERß), the main estrogen receptor subtype which is encoded by the estrogen receptor 2 (ESR2) gene, can mediate the action of estrogen in endometriosis. Although selective estrogen receptor modulators can target the ERß, they are not specific due to the wide distribution of ERß. Recently, long noncoding RNAs have been implicated in endometriosis. Therefore, we aim to explore and validate the downstream regulatory mechanism of ERß, and to investigate the potential role of long intergenic noncoding RNA 1018 (LINC01018) as a nonhormonal treatment for endometriosis. Our study demonstrates that the expression levels of ESR2 and LINC01018 are increased in ectopic endometrial tissues and reveals a significant positive correlation between the ESR2 and LINC01018 expression. Mechanistically, ERß directly binds to an estrogen response element located in the LINC01018 promoter region and activates LINC01018 transcription. Functionally, ERß can regulate the CDC25C/CDK1/CyclinB1 pathway and promote ectopic endometrial stromal cell proliferation via LINC01018 in vitro. Consistent with these findings, the knockdown of LINC01018 inhibits endometriotic lesion proliferation in vivo. In summary, our study demonstrates that the ERß/LINC01018/CDC25C/CDK1/CyclinB1 signaling axis regulates endometriosis progression.

Discovery of a potent and selective PARP1 degrader promoting cell cycle arrest via intercepting CDC25C-CDK1 axis for treating triple-negative breast cancer.

PARP1 is a multifaceted component of DNA repair and chromatin remodeling, making it an effective therapeutic target for cancer therapy. The recently reported proteolytic targeting chimera (PROTAC) could effectively degrade PARP1 through the ubiquitin-proteasome pathway, expanding the therapeutic application of PARP1 blocking. In this study, a series of nitrogen heterocyclic PROTACs were designed and synthesized through ternary complex simulation analysis based on our previous work. Our efforts have resulted in a potent PARP1 degrader D6 (DC50 = 25.23 nM) with high selectivity due to nitrogen heterocyclic linker generating multiple interactions with the PARP1-CRBN PPI surface, specifically. Moreover, D6 exhibited strong cytotoxicity to triple negative breast cancer cell line MDA-MB-231 (IC50 = 1.04 µM). And the proteomic results showed that the antitumor mechanism of D6 was found that intensifies DNA damage by intercepting the CDC25C-CDK1 axis to halt cell cycle transition in triple-negative breast cancer cells. Furthermore, in vivo study, D6 showed a promising PK property with moderate oral absorption activity. And D6 could effectively inhibit tumor growth (TGI rate = 71.4 % at 40 mg/kg) without other signs of toxicity in MDA-MB-321 tumor-bearing mice. In summary, we have identified an original scaffold and potent PARP1 PROTAC that provided a novel intervention strategy for the treatment of triple-negative breast cancer.

PUF60 promotes cell cycle and lung cancer progression by regulating alternative splicing of CDC25C.

Alternative splicing (AS) has been implicated in cell cycle regulation and cancer, but the underlying mechanisms are poorly understood. The poly(U)-binding splicing factor 60 (PUF60) is essential for embryonic development and is overexpressed in multiple types of cancer. Here, we report that PUF60 promotes mitotic cell cycle and lung cancer progression by controlling AS of the cell division cycle 25C (CDC25C). Systematic analysis of splicing factors deregulated in lung adenocarcinoma (LUAD) identifies that elevated copy number and expression of PUF60 correlate with poor prognosis. PUF60 depletion inhibits LUAD cell-cycle G2/M transition, cell proliferation, and tumor development. Mechanistically, PUF60 knockdown leads to exon skipping enriched in mitotic cell cycle genes, including CDC25C. Exon 3 skipping in the full-length CDC25C results in nonsense-mediated mRNA decay and a decrease of CDC25C protein, thereby inhibiting cell proliferation. This study establishes PUF60 as a cell cycle regulator and an oncogenic splicing factor in lung cancer.

6-Regioisomeric 5,8-quinolinediones as potent CDC25 inhibitors against colorectal cancers.

Precise and accurate control of cell cycle progression is required to maintain cell identity and proliferation. Failing to keep it will lead to genome instability and tumorigenesis. Cell Division Cycle 25 (CDC25) phosphatases are the key to regulating the activity of the master cell cycle controller, cyclin-dependent kinases (CDKs). Dysregulation of CDC25 has been shown to associate with several human malignancies. Here, we reported a series of derivatives of the CDC25 inhibitor, NSC663284, bearing quinones as core scaffolds and morpholin alkylamino side chains. Among these derivatives, the cytotoxic activity of the 6-isomer of 5,8-quinolinedione derivatives (6b, 16b, 17b, and 18b) displayed higher potency against colorectal cancer (CRC) cells. Compound 6b possessed the most antiproliferative activity, with IC50 values of 0.59 µM (DLD1) and 0.44 µM (HCT116). The treatment of compound 6b resulted in a remarkable effect on cell cycle progression, blocking S-phase progression in DLD1 cells straight away while slowing S-phase progression and accumulated cells in the G2/M phase in HCT116 cells. Furthermore, we showed that compound 6b inhibited CDK1 dephosphorylation and H4K20 methylation in cells. The treatment with compound 6b induced DNA damage and triggered apoptosis. Our study identifies compound 6b as a potent CDC25 inhibitor that induces genome instability and kills cancer cells through an apoptotic pathway, deserving further investigation to fulfill its candidacy as an anti-CRC agent.