Cyclin E/CDK2: DNA Replication, Replication Stress and Genomic Instability

Sonic hedgehog promotes Schwann cell proliferation through PI3K/AKT/cyclin E1 pathway

The proliferation of Schwann cells (SCs) is essential for both the development and regeneration of peripheral nervous system (PNS). Sonic hedgehog (Shh), a multifunctional signaling protein, plays pivotal roles in pattern formation, cell proliferation and cell survival during embryogenesis and tissue repair. While up-regulation of Shh in neurons and SCs following peripheral nerve injury has been associated with enhanced nerve regeneration its specific regulatory effects on SC proliferation remain poorly defined. In this study, we demonstrate dual expression patterns of Shh: significant up regulation in repair SCs post-injury and sustained high expression in immature SCs during developmental stages. Through lentivirus-mediated Shh knockdown in cultured SCs, we revealed that Shh silencing markedly suppresses SC proliferation by inducing G2/M-phase arrest. Transcriptomic profiling identified cell cycle dysregulation upon Shh depletion, characterized by diminished cyclin E1 expression. In mechanism, Shh maintains proliferative capacity through PI3K/AKT signaling activation, as evidenced by pathway inhibition following Shh silencing and subsequent rescue of proliferation deficits with PI3K/AKT agonists. These findings establish the PI3K/AKT/cyclin E1 axis as a central mechanism underlying Shh-mediated SC proliferation control. Our work elucidates the dual regulatory role of Shh in developmental and regenerative contexts while highlighting its potential as a therapeutic target for inherited peripheral neuropathies and peripheral nerve repair.

Development of 9H-purine scaffold as novel CDK2 inhibitors: Design, synthesis, and biological evaluation

Cyclin-dependent kinase 2 (CDK2), a crucial regulator in multiple oncogenic signaling pathways, has emerged as a promising target for the development of innovative anticancer therapies and overcoming resistance to CDK4/6 inhibitors. In this study, three series of compounds were designed and synthesized, using the CDK2 inhibitor fadraciclib (CYC065) as the lead compound, with 9H-purine as the core structure. The design incorporated reported structure-activity relationship data and utilized computer-aided drug design techniques. Compounds in series 1 explored the binding mode between the ATP ribose binding site in CDK2 and C2 substituents, while compounds in series 2 and 3 validated the feasibility of modifying the specific binding region with different substituents and investigated the effects of filling the CDK2 hydrophobic pocket at the N9 position with alkyl substituents. Three compounds, 1f, 2e, and 3a, demonstrated remarkable activity against CDK2-cyclin E2. Notably, 3a exhibited the most potent effect, with a CDK2-cyclin E2 IC50 value of 6.0 ± 0.1 nM, an MV4-11 IC50 value of 489.2 ± 0.2 nM, and excellent selectivity for CDK2. This study evaluated the impact of substitutions at the 2, 6, and 9 positions of the purine ring on the activity of CDK2 small molecule inhibitors. The findings offer a theoretical foundation for future research, broadening the structural diversity and scope of CDK2 inhibitor studies.

Revenge unraveling the fortress: Exploring anticancer drug resistance mechanisms in BC for enhanced therapeutic strategies

Breast cancer (BC) is the most prevalent form of cancer in women worldwide and the main cause of cancer-related fatalities in females. BC can be classified into various types based on where cancer has begun to grow or spread, specific characteristics that influence how cancer behaves, and treatment choices. BC is multifaceted, and due to its diverse nature, the mechanisms involved are complex and have not yet been understood. Overexpression and expression of various factors involved in the functioning of mechanisms lead to abnormal changes, providing an environment supporting cancer cell growth. Understanding BC risk factors and early diagnosis through screening techniques like mammography and diagnostic techniques such as imaging and biopsies has advanced significantly. A wide range of treatment options, including surgery, radiation, chemotherapy, targeted treatments, and hormonal therapies, are now available. Daily advancements are being made in the clinical treatment of BC. Still, BC drug resistance cases remain highly prevalent and are currently one of the biggest problems faced by medical science. To increase response rates and possibly lengthen survival, there is a critical requirement for novel medicines with minimal sensitivity to overcome drug resistance. This review classifies different mechanisms that are involved in the development of BC and workable pharmacological targets and explains how they relate to the development of BC drug resistance. By concentrating on the mechanisms covered in this review, we can have a deep understanding of different mechanisms and learn innovative ways to develop novel therapeutics for the disease to combat medication resistance.

Identification of differentially expressed genes and pathways in the post-ovulatory ampulla of cyclic pigs through a transcriptomics approach

BACKGROUND

Information on global transcriptomic changes in the porcine ampulla after ovulation is crucial for understanding of oviductal physiology at the molecular level. The objective of the present study was to investigate the differentially expressed genes (DEGs) and signalling pathways regulating the functionality of ampulla in pigs post-ovulation.

METHODS AND RESULTS

The RNA-sequencing of the post-ovulatory ampulla (POA) and early luteal ampulla (ELA) tissues was conducted using Illumina NextSeq2000. The R package NOISeq was used to obtain significantly differentially expressed genes (DEGs) with the probability of differential expression (1-FDR) value ≥ 0.95 and log2 fold change (log2FC) ≥ 1, which revealed 817 DEGs (657 up- and 160 down-regulated) in the POA vs. ELA group comparison. These DEGs were functionally annotated with various gene ontology terms like sterol biosynthetic process, growth, cell migration, and Reactome pathways like signal transduction, metabolism, and cell cycle, indicating key role of these molecular events in POA. The WNT, TNFR2 non-canonical NF-kB, and hedgehog signalling pathways along with the activation of the immune system process, were enriched in the POA vs. ELA group, which indicates their role in cell-cell interactions and cell fate determination in remodelling the oviductal microenvironment during transition from estrogen to progesterone domination. The highly connected upregulated hub genes ESR1, RAD51, YARS1, TYMS and CDK2 can be regarded as key regulatory factors in synchronizing the changes in POA at the molecular level in the oviduct.

CONCLUSION

The present study revealed several DEGs, signalling pathways and novel modulatory factors associated with the ampullary physiology during early embryonic development in the POA, which may influence fertility and litter size in pigs.

Suppressing proteasome activity enhances sensitivity to actinomycin D in diffuse anaplastic Wilms tumor

Wilms tumor is the most common pediatric kidney cancer, and diffuse anaplastic Wilms tumor is the most chemoresistant subtype. Here, we explore how Wilms tumor cells evade the chemotherapy actinomycin D, which inhibits ribosomal RNA biogenesis. Using ribosome profiling, protein arrays, and a genome-wide knockout screen, we describe how actinomycin D disrupts protein homeostasis and blocks cell-cycle progression. When ribosomal capacity is limited by actinomycin D treatment, anaplastic Wilms tumor cells preferentially translate proteasome components. Next, we find that the proteasome inhibitor bortezomib sensitizes cells to actinomycin D treatment in vitro and prolongs survival in xenograft models. Lastly, increased levels of proteasome components are associated with anaplastic histology and worse prognosis in Wilms tumor patients. In sum, maintaining protein homeostasis is critical for Wilms tumor proliferation, and it can be therapeutically disrupted by blocking protein synthesis or turnover.

Profiling the Anti-Photoaging Impact of Titanium Dioxide and Zinc Oxide Nanoparticles: A Focus on Signaling Pathways

Inorganic nanoparticles are known to protect skin from ultraviolet rays (UVR) and delay photoaging. However, the photoprotective effects of these nanoparticles have not been broadly analyzed at a genetic level. The study objectives are as follows: (1) to investigate how UV-only and complete solar light can affect signaling pathways and genes related to photoaging in human dermal fibroblasts; (2) to investigate how TiO2 and ZnO nanoparticles provide photoprotection at a genetic level. RNAseq identified pathways and genes that were significantly affected by both irradiation conditions. Extracellular matrix (ECM) remodeling, inflammation, and cell cycle-related genes were subsequently validated by qPCR. The photoprotective properties of < 100 nm TiO2 and ZnO dispersions at a 25% active level were analyzed through quantitative differences in the irradiation-induced expression of these genes. There were < 15 signaling pathways affected by UV and complete solar light (p-value (-log10) > 1). Significant differences in gene expression following irradiation were found in MMP1, MMP3, PTGS1, PTGES, MDM2, CDKN1A, and CCNE2 (p ≤ 0.05) through qPCR. TiO2 and ZnO minimized the irradiation-induced expression of genes involved in the inhibition of matrix metalloproteinases, prostanoid biosynthesis, and cell cycle pathways. Photoprotection was best observed in cell cycle-related genes, showing expression differences of up to 74% (p ≤ 0.0001). However, no distinct differences in photoprotection between TiO2 and ZnO were found. The findings from this study serve as a framework for future optimization and development of inorganic sunscreen formulations to target genes that contribute to different aspects of skin aging.

Genetic modeling of ELP1-associated Sonic hedgehog medulloblastoma identifies MDM2 as a selective therapeutic target

Germline loss-of-function (LOF) variants in Elongator acetyltransferase complex subunit 1 (ELP1) are the most prevalent predisposing genetic events in childhood medulloblastoma (MB), accounting for ∼30% of the Sonic hedgehog (SHH) 3 subtype. The mechanism(s) by which germline ELP1 deficiency provokes SHH-MB pathogenesis remain unknown. Genetically engineered mice mimicking heterozygous Elp1 LOF (Elp1HET) seen in affected germline carriers exhibit hallmark features of premalignancy in cerebellar granule neuron progenitors (GNPs), including increased DNA replication stress, genomic instability, accelerated cell cycle, and stalled differentiation. Orthotopic transplantation of Elp1HET GNPs harboring somatic Ptch1 inactivation yields SHH-MB-like tumors with compromised p53 signaling, providing a plausible explanation for the exclusivity of ELP1-associated MBs in the SHH-3 subtype. Preclinical treatment of ELP1-mutant patient-derived xenografts with an FDA-approved MDM2 inhibitor reactivates p53-dependent apoptosis and extends survival. Our findings functionally substantiate the role of ELP1 deficiency in SHH-MB predisposition and nominate therapeutics targeting MDM2 as a rational treatment option.

Exploring the Anti-Leukemic Effect of the Synthetic Retinoid ST1926 on Malignant T Cells: A Comprehensive Proteomics Approach

T-cell malignancies represent a group of complex cancers arising from T cells and include aggressive subtypes such as Adult T-cell Leukemia/Lymphoma (ATL) and T-cell Acute Lymphoblastic Leukemia (T-ALL). Patients with these aggressive subtypes still represent an unmet medical condition. The synthetic adamantyl retinoid ST1926, a potent DNA polymerase-α inhibitor, proved a promising potency in preclinical models of ATL and peripheral T-cell lymphoma. Using advanced liquid chromatography-mass spectrometry (LC-MS/MS) techniques, we explored the effects of ST1926 on global protein expression in ATL (HuT-102) and T-ALL (MOLT-4) cells. We demonstrate that ST1926 triggers differentiation and apoptosis in malignant T-cells while halting tumor progression. Evidence at the proteomics level reveals the impact of ST1926 on crucial DNA replication enzymes and cell cycle regulation, highlighting its potential to reduce leukemogenesis and promote apoptosis. Our findings underscore the potential of ST1926 as an innovative therapeutic approach to address these aggressive T-cell malignancies, providing valuable insights into developing new targeted therapies and improving the outcomes and prognosis of patients with these challenging diseases.

CCNE1 stabilizes ANLN by counteracting FZR1-mediated the ubiquitination modification to promotes triple negative breast cancer cell stemness and progression

Triple-negative breast cancer (TNBC) is an aggressive subtype lacking targeted therapies. In this study, we aimed to investigate the pivotal role of cyclin E1 (CCNE1) in the onset and progression of TNBC using comprehensive bioinformatic analysis and functional validation. We found significantly elevated CCNE1 expression in TNBC tissues compared to normal, which correlated with poor prognosis. Functional assessments in vitro and in vivo demonstrated that knockdown of CCNE1 impaired the proliferative, migratory, and invasive capacities of TNBC cells, promoted apoptosis, and reduced tumorigenicity. Furthermore, CCNE1 sustains the stem-like properties of TNBC cells and fuels malignant progression through Anillin (ANLN). Mechanistically, CCNE1 interacted with ANLN and stabilized its protein levels by counteracting Fizzy-related protein 1 (FZR1)-mediated the ubiquitination modification in TNBC. Mutation of the ubiquitination site in ANLN affected CCNE1's regulatory functions but not ANLN's intrinsic properties. Taken together, these findings underscore the role of CCNE1 in promoting TNBC cell stemness and progression via competitive inhibition of FZR1-mediated ANLN ubiquitination. Consequently, targeting CCNE1 emerges as a promising therapeutic approach for breast cancer.

Combination therapy and dual-target inhibitors based on cyclin-dependent kinases (CDKs): Emerging strategies for cancer therapy

Cyclin-dependent kinases (CDKs) are pivotal regulators of the cell cycle and transcriptional machinery, making them attractive targets for cancer therapy. While CDK inhibitors have demonstrated promising clinical outcomes, they also face challenges in enhancing efficacy, particularly in overcoming drug resistance. Combination therapies have emerged as a key strategy to augment the effectiveness of CDK inhibitors when used alongside other kinase inhibitors or non-kinase-targeted agents. Dual-target inhibitors that simultaneously inhibit CDKs and other oncogenic drivers are gaining attention, offering novel avenues to optimize cancer therapy. Based on the structural characterization and biological functions of CDKs, this review comprehensively examines the structure-activity relationship (SAR) of existing dual-target CDK inhibitors from a drug design perspective. We also thoroughly investigate the preclinical studies and clinical translational potential of combination therapies and dual-target inhibitors. Tailoring CDK inhibitors to specific cancer subtypes and therapeutic settings will inspire innovative approaches for the next generation of CDK-related therapies, ultimately improving patient survival.

UPS and Kinases-Gatekeepers of the G1/S Transition

The G1/S transition is a highly regulated and pivotal checkpoint in the cell cycle, where the cell decides whether to commit to DNA replication and subsequent division or enter a non-dividing state. This checkpoint serves as a critical control point for preventing uncontrolled cell proliferation and maintaining genomic stability. The major driving force underlying the G1/S transition is the sequential activation of Cyclin-dependent kinases (CDKs), which is regulated by the coordinated binding of Cyclin partners, as well as the phosphorylation and ubiquitin-mediated degradation of both Cyclin partners and Cyclin-dependent kinase inhibitors (CKIs). Various E3 ligase families govern the timely degradation of these regulatory proteins, with their activity intricately controlled by phosphorylation events. This coordination enables the cells to efficiently translate the environmental cues and molecular signaling inputs to determine their fate. We explore the evolution of three distinct models describing the G1/S transition, highlighting how the traditional linear model is being challenged by recent paradigm shifts and conflicting findings. These advances reveal emerging complexity and unresolved questions in the field, particularly regarding how the latest insights into coordinated phosphorylation and ubiquitination-dependent degradation integrate into contemporary models of the G1/S transition.

SET-binding protein 1 (SETBP1) suppresses cell proliferation in estrogen receptor-positive breast cancer

BACKGROUND

The single-nucleotide polymorphism rs6507583 at the promoter of SET-binding protein 1 (SETBP1) was implicated in estrogen receptor (ER)-positive breast carcinogenesis. Here, we evaluated the clinical and biological relevance of SETBP1 expression in ER-positive breast cancer (BC).

METHODS

The associations between SETBP1 expression and clinical outcomes in BC patients were analyzed in independent cohorts. The localizations of SETBP1 expression in BC tissues were observed by immunohistochemical staining. Pathway analyses were conducted using TCGA dataset. In vitro proliferation assay, protein phosphatase 2A (PP2A) activity assay, and gene expression analysis were performed in SETBP1-knockdown ER-positive BC cells. We investigated the factors influencing SETBP1 mRNA expression using TCGA dataset. rs6507583 presence and SETBP1 mRNA expression in 11 mammary cell lines and 56 BC tissue samples were examined by target sequencing and RT-qPCR, respectively.

RESULTS

SETBP1 was downregulated in BC cells compared with normal ductal epithelial cells. Low SETBP1 mRNA expression was an independent prognostic factor for poor recurrence-free survival. Pathway analyses revealed an inverse relationship between decreased SETBP1 expression and the expression of E2F, MYC, and G2M checkpoint target genes in BC tissues. SETBP1 knockdown promoted proliferation, inhibition of PP2A activity, and phosphorylation of MAPK in ER-positive BC. Low SETBP1 expression was influenced by high SETBP1 promoter methylation and DNA copy number SETBP1 deletion. SETBP1 expression with rs6507583 was lower than without rs6507583 in BC.

CONCLUSIONS

We demonstrated that low SETBP1 expression could be a poor prognostic biomarker that promotes ER-positive BC proliferation, possibly via phosphorylation of MAPK.

Computational Estimation of Residence Time on Roniciclib and Its Derivatives against CDK2: Extending the Use of Classical and Enhanced Molecular Dynamics Simulations

Residence time is a crucial parameter for assessing the functional efficacy of drugs, quantifying the duration of a drug's binding to its target protein. It is directly related to therapeutic effects and the dosing regimen. Several factors can influence the residence time, including drug-protein binding kinetics and the unbinding pathways. Understanding the efficacy of a drug requires the characterization of both its binding kinetics and unbinding pathways from the drug-protein complex. By employing our previous computational protocol that uses enhanced sampling techniques such as well-tempered metadynamics (WT-MetaD) and classical molecular dynamics (cMD) simulations, it was possible to elucidate the inhibitor unbinding pathways and identify molecular determinants that extend the residence time in a set of cyclin-dependent kinase 2 (CDK2) inhibitors. In this study, using WT-MetaD, the relative residence times of roniciclib and eight derivatives were quantified on the nanosecond timescale. Notably, substituting the R5 position of the aminopyridine core with larger substituents significantly prolonged the computational residence time, which correlated well with experimental data (R 2 = 0.83). Our computational simulations reveal the critical importance of specific amino acids, including Phe80, Lys33, and Asp145, in maintaining the stability of the protein-inhibitor complex. These residues are key in keeping the hydration network around them, affecting the inhibitor binding duration. The hydrogen bond interaction between residue Asp145 and roniciclib and its derivatives is particularly noteworthy, significantly influencing the electrostatic contribution to the binding free energy when the halogen substituent size increases. Furthermore, our analysis of protein flexibility at the C-terminus and N-terminus angles revealed a relationship with the size of the R5 substituent in the bound inhibitor, supported by principal component analysis. Additionally, different unbinding pathways were proposed, where it was found that inhibitors can dissociate from the CDK2 binding site through two principal routes: the α-helix D and β-1 and β-2 segments.

CCNE2 promotes cisplatin resistance and affects prognosis of head and neck squamous cell carcinoma by targeting MNAT1

Cell cycle protein E2 (CCNE2) is a member of the Cyclin family, known for driving tumor cell proliferation and invasion. However, the mechanism of its action in head and neck squamous cell carcinoma (HNSCC) remains unclear. The aim of this study is to investigate the relationship between CCNE2 and cisplatin resistance and survival prognosis of head and neck squamous cell carcinoma. We performed transcriptomic sequencing of HNSCC and HNSCC/DDP. Kaplan-Meier analysis and COX regression analysis were used to evaluate the relationship between CCNE2 expression and survival prognosis of HNSCC patients. Multiple potential biological functions of CCNE2 in HNSCC were identified using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Single-sample gene set enrichment analysis (ssGSEA) was used to explore tumor immune infiltration. The potential mechanism of CCNE2 was explored by molecular docking and immunoprecipitation. Cell migration, cell invasion and cell proliferation assays were used to investigate the mechanism of CCNE2 in HNSCC. CCNE2 is up-regulated in HNSCC tissues and cell lines and is associated with poor prognosis. The high expression of CCNE2 in HNSCC is associated with clinical significance. GO and KEGG analysis showed that ccne2 related genes may be involved in the regulation of DNA double-strand break repair and DNA metabolic process. CCNE2 expression was positively correlated with the infiltration levels of helper T cells, Tcm cells and Th2 cells, and negatively correlated with the infiltration levels of DC, neutrophils and pDC. CCNE2 regulates the invasion, migration and proliferation of HNSCC cells by targeting MNAT1. CCNE2 also altered cisplatin resistance in HNSCC/DDP. CCNE2 may be an independent prognostic biomarker of HNSCC through MNAT1, which provides new ideas for cisplatin resistance and therapeutic targets of HNSCC.

The involvement of cyclin-dependent kinase 7 (CDK7) and 9 (CDK9) in coordinating transcription and cell cycle checkpoint regulation

Cells regulate the expression of cell cycle-related genes, including cyclins essential for mitosis, through the transcriptional activity of the positive transcription elongation factor b (P-TEFb), a complex comprising CDK9, cyclin T, and transcription factors. P-TEFb cooperates with CDK7 to activate RNA polymerase. In response to DNA stress, the cell cycle shifts from mitosis to repair, triggering cell cycle arrest and the activation of DNA repair genes. This tight coordination between transcription, cell cycle progression, and DNA stress response is crucial for maintaining cellular integrity. Cyclin-dependent kinases CDK7 and CDK9 are central to both transcription and cell cycle regulation. CDK7 functions as the CDK-activating kinase (CAK), essential for activating other CDKs, while CDK9 acts as a critical integrator of signals from both the cell cycle and transcriptional machinery. This review elucidates the mechanisms by which CDK7 and CDK9 regulate the mitotic process and cell cycle checkpoints, emphasizing their roles in balancing cell growth, homeostasis, and DNA repair through transcriptional control.

Profiling the Activity of the Potent and Highly Selective CDK2 Inhibitor BLU-222 Reveals Determinants of Response in CCNE1-Aberrant Ovarian and Endometrial Tumors

BLU-222 is an investigational, potent, highly selective, orally bioavailable cyclin-dependent kinase 2 (CDK2) inhibitor in clinical development. BLU-222 demonstrated robust antitumor activity in select CCNE1-high ovarian and endometrial cancer models. We used a combination of CRISPR whole-genome screens coupled with targeted genetic and pharmacologic approaches in ovarian and endometrial cell lines to identify biological determinants to predict BLU-222 monotherapy activity. Rb and p16 expression were biomarkers that enriched for CDK2-dependency/BLU-222 sensitivity in CCNE1-overexpressed, nonamplified cells. Furthermore, intact Rb and low p16 expression predicted a BLU-222 and CDK4/6 inhibitor combination response. BLU-222 demonstrated robust activity in combination with carboplatin or paclitaxel in CCNE1-aberrant models, rendering chemotherapy-resistant tumors strongly sensitive to the combination. These findings demonstrate that response to CDK2 inhibition by BLU-222 can be further predicted using a combinatorial biomarker signature that could refine patient selection criteria in CCNE1-high patients and support clinical development. Significance: The identification of biomarkers of response to the CDK2-selective inhibitor BLU-222 and effective combinations with CDK4/6 inhibitors or chemotherapy could enable precision medicine strategies for CDK2 inhibition in ovarian and endometrial cancer. See related article by Dommer and colleagues, p. 1310.

Distinct Allosteric Networks in CDK4 and CDK6 in the Cell Cycle and in Drug Resistance

Cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) are key regulators of the G1-S phase transition in the cell cycle. In cancer cells, CDK6 overexpression often outcompetes CDK4 in driving cell cycle progression, contributing to resistance against CDK4/6 inhibitors (CDK4/6i). This suggests distinct functional and conformational differences between these two kinases, despite their striking structural and sequence similarities. Understanding the mechanisms that differentiate CDK4 and CDK6 is crucial, as resistance to CDK4/6i-frequently linked to CDK6 overexpression-remains a significant therapeutic challenge. Notably, CDK6 is often upregulated in CDK4/6i-resistant cancers and rapidly proliferating hematopoietic stem cells, underscoring its unique regulatory roles. We hypothesize that their distinct conformational dynamics explain their differences in phosphorylation of retinoblastoma protein, Rb, inhibitor efficacy, and cell cycle control. This leads us to question how their dissimilar conformational dynamics encode their distinct actions. To elucidate their differential activities, molecular mechanisms, and inhibitor binding, we combine biochemical assays and molecular dynamics (MD) simulations. We discover that CDK4 and CDK6 have distinct allosteric networks connecting the β3-αC loop and the G-loop. CDK6 exhibits stronger coupling and shorter path lengths between these regions, resulting in higher kinase activity upon cyclin binding and impacting inhibitor specificity. We also discover an unrecognized role of the unstructured CDK6 C-terminus, which allosterically connects and stabilizes the R-spine, facilitating slightly higher activity. Our findings bridge the gap between the structural similarity and functional divergence of CDK4 and CDK6, advancing the understanding of kinase regulation in cancer biology.

The effects of flavonoid baicalein on miRNA expressions in cancer: a systematic review

Baicalein from Scutellaria baicalensis influences miRNA expression in various cancers, affecting key signaling pathways (PI3K/AKT, Wnt/β-catenin, mTOR) and processes like tumor growth, apoptosis, and metastasis. miRNAs, as small non-coding RNAs, play crucial roles in the cancer pathogenesis-associated gene regulations. This study is aimed at systematically reviewing the effects of baicalein on miRNA expression in various cancers. A comprehensive systematic review was conducted following PRISMA guidelines to investigate the impact of baicalein on miRNA expression in cancer. Databases including PubMed, Scopus, and Web of Science were systematically searched using key search terms. Inclusion criteria encompassed studies reporting changes in miRNA expression following baicalein treatment in cancer cell lines and animal models. Data extraction and risk of bias assessment based on SYRCLE's risk of bias tool were performed to ensure methodological rigor and reliability of the findings. Fifteen studies meeting the inclusion criteria were included in the systematic review. Baicalein impacts miRNA expression in cancers like hepatocellular carcinoma, breast, cervical, ovarian, and gastric cancers, suggesting its potential as a multi-cancer therapeutic. Baicalein regulates tumor-related genes (HDAC10, MDM2, Bcl-2/Bax, and Cyclin E1) and signaling molecules (AKT, FOXO3α), affecting cell viability, apoptosis, and cell cycle, indicating targeted therapeutic potential. In vitro and in vivo studies show baicalein inhibits tumor growth, enhances apoptosis, and regulates cell proliferation, supporting its anticancer effects. Baicalein exhibits potential in modulating miRNA expression in cancer, offering avenues for therapeutic intervention. However, methodological rigor in future studies is essential to enhance the reliability and validity of findings. Comprehensive understanding of baicalein's effects on miRNA expression holds promise for developing novel cancer treatment strategies.

c-Jun promotes neuroblastoma cell differentiation by inhibiting APC formation via CDC16 and reduces neuroblastoma malignancy

Neuroblastoma is a pediatric embryonal malignancy characterized by impaired neuronal differentiation. Differentiation status in neuroblastoma strongly affects the clinical outcome, thus, enforcement of differentiation becomes a treatment strategy for this disease. However, the molecular mechanisms that control neuroblastoma differentiation are poorly understood. As an extensively studied protein of the activator protein-1 (AP-1) complex, c-Jun is involved in numerous cell regulations such as proliferation, survival and differentiation. In the current study, we demonstrated that c-Jun expression was upregulated by retinoic acid (RA) and flow cytometry assay indicated c-Jun overexpression arrested cell cycle to G1 phase, which, in turn, promoted the initiation of neuroblastoma cell differentiation. Co-immunoprecipitation (co-IP) assay showed that c-Jun competitively interacted with CDC16, a key subunit in anaphase-promoting complex (APC), resulting in reduced APC formation and inhibition of cell cycle progression. Furthermore, EdU proliferation assay and transwell experiment showed that c-Jun overexpression inhibited neuroblastoma cell proliferation and migration via interacting and sequestering CDC16. These findings identify c-Jun as a key regulator of neuroblastoma cell cycle and differentiation and may represent a promising therapeutic target to induce neuroblastoma differentiation via the interaction between c-Jun and CDC16.

Milciclib-mediated CDK2 inhibition to boost radiotherapy sensitivity in colorectal cancer

Background

Colorectal cancer (CRC) ranks as the third most common cancer globally. Neoadjuvant radiotherapy is the standard treatment for locally advanced rectal cancer; however, primary or acquired resistance often leads to treatment failure. Identifying new targets to overcome radiotherapy resistance in CRC is crucial for improving patient outcomes.

Methods

To evaluate the antitumor effects of Milciclib in CRC cells, we conducted assays measuring cell viability, cell cycle progression, and apoptosis in HCT116 and RKO cell lines following Milciclib treatment. Additionally, CRC cells were treated with a combination of Milciclib and irradiation to determine whether Milciclib could enhance their radiosensitivity. The efficacy of Milciclib was also assessed in radiation-resistant CRC cells.

Results

The results of cytotoxicity and proliferation assays indicated that the IC50 values of Milciclib for human colorectal cancer cell lines HCT-116 and RKO, based on cell viability measurements, were 0.275 μM and 0.403 μM, respectively. Milciclib induced a dose-dependent reduction in the proportion of CRC cells in the G2/M phase and promoted apoptosis. When combined with irradiation, Milciclib led to a 20% increase in the proportion of cells in the G1 phase and a 10% decrease in the G2 phase, suggesting an alteration in cell cycle distribution. Additionally, Milciclib impaired DNA damage repair by inhibiting Rad51, thereby enhancing radiation sensitivity. In radiation-resistant CRC cells, the combination of Milciclib and irradiation demonstrated increased efficacy, with a sensitizer enhancement ratio (SER) above 1, indicating a potential radiosensitizing effect.

Conclusion

Milciclib exhibits antitumor activity in CRC cells as a monotherapy and enhances the effectiveness of radiotherapy when used in combination. It disrupts the G2/M checkpoint and impairs DNA repair mechanisms. These findings suggest that Milciclib has the potential to be an effective therapeutic agent for CRC.

Impact of intermittent high-dose radon exposures on lung epithelial cells: proteomic analysis and biomarker identification

Lung cancer is the most prevalent cancer worldwide, and radon exposure is ranked as the second risk factor after cigarette smoking. It has been reported that radon induces deoxyribonucleic acid damage and oxidative stress in cells. However, the protein profile and potential biomarkers for early detection of radon-induced lung cancer remain unknown. In this study, we aimed to investigate the effects of intermittent high-dose radon exposure on lung epithelial cells, analyze protein profiles and identify potential biomarkers for diagnosis of radon-related lung cancer. Human lung epithelial cells (A549) were exposed to radon (1000 Bq/m3) for 30 min daily for 7 days. Cell viability was measured using the WST-1 assay, and liquid chromatography-mass spectrometry proteomic analysis was performed. Differentially expressed proteins and gene ontology (GO) enrichment were analyzed. Our findings showed that intermittent high-radon exposure reduced A549 cell viability over time. Proteomic analysis identified proteins associated with stressed-induced apoptosis, mitochondrial adaptation, nuclear integrity and lysosomal degradation. These proteins are related to catabolism, stress response, gene expression and metabolic processes in the biological process of GO analysis. We highlighted specific proteins, including AKR1B1, CDK2, DAPK1, PRDX1 and ALHD2 with potential as biomarkers for radon-related lung cancer. In summary, intermittent high-dose radon exposure affects cellular adaptions of lung epithelial cells including stress-induced apoptosis, mitochondrial dysfunctions and immune regulation. The identified proteins may serve as diagnostic biomarkers or therapeutic targets for radon-related lung cancer.

Genes as Genome Stabilizers in Pluripotent Stem Cells

Pluripotent stem cells, comprising embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), are characterized by their self-renewal capacity and the ability to differentiate into cells of all three germ layers of an adult animal. Out of the two, iPSCs are generated through the reprogramming of somatic cells by inducing a pluripotency-specific transcriptional program. This process requires a resetting of the somatic cell genome to a pluripotent cell-specific genome, resulting in cellular stress at genomic, epigenetic, and transcriptional levels. Notably, in contrast to the predominant compact and inactive organization of chromatin in somatic cells, the chromatin in ESCs and iPSCs is open. Furthermore, maintaining a pluripotent state needs a plethora of changes in the genetic landscape of the cells. Here, we attempt to elucidate how certain genes safeguard genomic stability in ESCs and iPSCs, aiding in the complex cellular mechanisms that regulate self-renewal, pluripotency, and somatic reprogramming.

Translational Advances in Oncogene and Tumor-Suppressor Gene Research

Cancer, characterized by the uncontrolled proliferation of cells, is one of the leading causes of death globally, with approximately one in five people developing the disease in their lifetime. While many driver genes were identified decades ago, and most cancers can be classified based on morphology and progression, there is still a significant gap in knowledge about genetic aberrations and nuclear DNA damage. The study of two critical groups of genes-tumor suppressors, which inhibit proliferation and promote apoptosis, and oncogenes, which regulate proliferation and survival-can help to understand the genomic causes behind tumorigenesis, leading to more personalized approaches to diagnosis and treatment. Aberration of tumor suppressors, which undergo two-hit and loss-of-function mutations, and oncogenes, activated forms of proto-oncogenes that experience one-hit and gain-of-function mutations, are responsible for the dysregulation of key signaling pathways that regulate cell division, such as p53, Rb, Ras/Raf/ERK/MAPK, PI3K/AKT, and Wnt/β-catenin. Modern breakthroughs in genomics research, like next-generation sequencing, have provided efficient strategies for mapping unique genomic changes that contribute to tumor heterogeneity. Novel therapeutic approaches have enabled personalized medicine, helping address genetic variability in tumor suppressors and oncogenes. This comprehensive review examines the molecular mechanisms behind tumor-suppressor genes and oncogenes, the key signaling pathways they regulate, epigenetic modifications, tumor heterogeneity, and the drug resistance mechanisms that drive carcinogenesis. Moreover, the review explores the clinical application of sequencing techniques, multiomics, diagnostic procedures, pharmacogenomics, and personalized treatment and prevention options, discussing future directions for emerging technologies.

Distinct allosteric networks in CDK4 and CDK6 in the cell cycle and in drug resistance

Cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) are key regulators of the G1-S phase transition in the cell cycle. In cancer cells, CDK6 overexpression often outcompetes CDK4 in driving cell cycle progression, contributing to resistance against CDK4/6 inhibitors (CDK4/6i). This suggests distinct functional and conformational differences between these two kinases, despite their striking structural and sequence similarities. Understanding the mechanisms that differentiate CDK4 and CDK6 is crucial, as resistance to CDK4/6i-frequently linked to CDK6 overexpression-remains a significant therapeutic challenge. Notably, CDK6 is often upregulated in CDK4/6i-resistant cancers and rapidly proliferating hematopoietic stem cells, underscoring its unique regulatory roles. We hypothesize that their distinct conformational dynamics explain their differences in phosphorylation of retinoblastoma protein, Rb, inhibitor efficacy, and cell cycle control. This leads us to question how their dissimilar conformational dynamics encode their distinct actions. To elucidate their differential activities, molecular mechanisms, and inhibitor binding, we combine biochemical assays and molecular dynamics (MD) simulations. We discover that CDK4 and CDK6 have distinct allosteric networks connecting the β3-αC loop and the G-loop. CDK6 exhibits stronger coupling and shorter path lengths between these regions, resulting in higher kinase activity upon cyclin binding and impacting inhibitor specificity. We also discover an unrecognized role of the unstructured CDK6 C-terminus, which allosterically connects and stabilizes the R-spine, facilitating slightly higher activity. Our findings bridge the gap between the structural similarity and functional divergence of CDK4 and CDK6, advancing the understanding of kinase regulation in cancer biology.

HOXA1 Contributes to Bronchial Epithelial Cell Cycle Progression by Regulating p21/CDKN1A

Airway basal cells proliferate and regenerate airway epithelium after injury. The first step during airway epithelial repair is airway basal cell proliferation to close the wound. Previously, we demonstrated that homeobox (HOX) A1 expression is reduced in airway stem cells isolated from chronic obstructive pulmonary disease. HOXA1 is a developmental gene and plays a role in hematopoietic stem cell proliferation and differentiation, but its contribution to airway epithelial cell migration and proliferation is not known. In this study, we generated a HOXA1 knockout bronchial epithelial cell line using CRISPR/CAS9 technology followed by clonal expansion to investigate the role of HOXA1 in airway epithelial cell proliferation and migration. Compared to WT, HOXA1 knockout bronchial epithelial cells generated smaller spheroids than WT type cells, indicating a defect in cell proliferation. In the scratch assay, HOXA1 knockout cells showed substantial delay in migrating to the wounded area. By single-cell RNA sequencing and the clustering of cells based on HOXA1 expression, we identified a downregulation of genes involved in cell cycle progression. A cell cycle analysis by flow cytometry indicated partial cell cycle arrest at the G0/G1 phase in HOXA1 knockout cells. This was associated with a reduced expression of Cyclin E1 and an increased expression of the cyclin-dependent kinase inhibitor p21/CDKN1A. These results indicate that HOXA1 may contribute to cell proliferation by regulating cell cycle progression via p21/CDKN1A in airway epithelial cells.

COL6A1 Promotes Milk Production and Fat Synthesis Through the PI3K-Akt/Insulin/AMPK/PPAR Signaling Pathways in Dairy Cattle

Exploring functional genes/sites and the molecular regulatory mechanisms underlying milk production traits in dairy cattle is crucial for improving the development of the dairy industry and human health. In our previous work, the gene collagen type VI alpha 1 (COL6A1) was found to be involved in milk fat metabolism from liver transcriptome data across various lactation periods of cows. Through the integration of Cattle QTLdb, FarmGTEx and qPCR data, the COL6A1 gene was found to be located within known quantitative trait loci (QTLs), adjacent to single-nucleotide polymorphisms (SNPs) associated with milk traits, and highly expressed in the mammary gland. After employing RNA interference technology, cell function and phenotype tests in bovine mammary epithelial cells revealed that the COL6A1 gene accelerated cell proliferation, cell cycle progression, and the synthesis of lipids and triglycerides by regulating the PI3K-Akt, insulin, AMPK, and PPAR signaling pathways. Notably, 22 SNPs within COL6A1 had potential breeding value because they were significantly associated with milk production traits, especially with milk fat. In summary, our findings demonstrate that the COL6A1 gene promotes milk production and fat synthesis via the PI3K-Akt/insulin/AMPK/PPAR signaling pathways, providing valuable genetic information for molecular breeding programs for dairy cattle.

An allosteric cyclin E-CDK2 site mapped by paralog hopping with covalent probes

More than half of the ~20,000 protein-encoding human genes have paralogs. Chemical proteomics has uncovered many electrophile-sensitive cysteines that are exclusive to subsets of paralogous proteins. Here we explore whether such covalent compound-cysteine interactions can be used to discover ligandable pockets in paralogs lacking the cysteine. Leveraging the covalent ligandability of C109 in the cyclin CCNE2, we substituted the corresponding residue in paralog CCNE1 to cysteine (N112C) and found through activity-based protein profiling that this mutant reacts stereoselectively and site-specifically with tryptoline acrylamides. We then converted the tryptoline acrylamide-CCNE1-N112C interaction into in vitro NanoBRET (bioluminescence resonance energy transfer) and in cellulo activity-based protein profiling assays capable of identifying compounds that reversibly inhibit both the N112C mutant and wild-type CCNE1:CDK2 (cyclin-dependent kinase 2) complexes. X-ray crystallography revealed a cryptic allosteric pocket at the CCNE1:CDK2 interface adjacent to N112 that binds the reversible inhibitors. Our findings, thus, show how electrophile-cysteine interactions mapped by chemical proteomics can extend the understanding of protein ligandability beyond covalent chemistry.

Mink enteritis virus infection induced cell cycle arrest and autophagy for its replication

Mink enteritis virus (MEV) is an important pathogen causing mink viral enteritis. The mechanisms of cell cycle arrest induced by MEV infection and the roles of autophagy in MEV replication remain unclear. In this study, the roles of MEV NS1 protein in inducing cell cycle arrest were investigated, using the in vitro CRFK cell models. As a result, MEV infection increased the proportion of the cells in S phase, inducing S phase arrest. MEV NS1 protein also led to cycle arrest in S phase. And the deletions of NLS and TAD significantly weakened the ability of NS1 protein to cause cycle arrest in S phase, and NLS and TAD were the indispensable domains of NS1 protein. Furthermore, proteome profiling of the cells infected with MEV at the early stage demonstrated that the autophagy-related protein TRIM23 was significantly up-regulated during MEV infection. To investigate the effects of TRIM23 on MEV replication, the cell models were established, using siRNAs targeting TRIM23. The knockdown of TRIM23 resulted in the decreases in the levels of TBK1 protein and the phosphorylated p62 protein, and an increase in the level of p62 protein in the cells infected with MEV, indirectly influencing virus replication. The findings implied that S phase arrest and the up-regulated TRIM23 induced by MEV infection played the important roles in MEV replication.

Cell cycle dysregulation in cancer

Cancer is a systemic manifestation of aberrant cell cycle activity and dysregulated cell growth. Genetic mutations can determine tumor onset by either augmenting cell division rates or restraining normal controls such as cell cycle arrest or apoptosis. As a result, tumor cells not only undergo uncontrolled cell division but also become compromised in their ability to exit the cell cycle accurately. Regulation of cell cycle progression is enabled by specific surveillance mechanisms known as cell cycle checkpoints, and aberrations in these signaling pathways often culminate in cancer. For instance, DNA damage checkpoints, which preclude the generation and augmentation of DNA damage in the G1, S, and G2 cell cycle phases, are often defective in cancer cells, allowing cell division in spite of the accumulation of genetic errors. Notably, tumors have evolved to become dependent on checkpoints for their survival. For example, checkpoint pathways such as the DNA replication stress checkpoint and the mitotic checkpoint rarely undergo mutations and remain intact because any aberrant activity could result in irreparable damage or catastrophic chromosomal missegregation leading to cell death. In this review, we initially focus on cell cycle control pathways and specific functions of checkpoint signaling involved in normal and cancer cells and then proceed to examine how cell cycle control and checkpoint mechanisms can provide new therapeutic windows that can be exploited for cancer therapy. SIGNIFICANCE STATEMENT: DNA damage checkpoints are often defective in cancer cells, allowing cell division in spite of the accumulation of genetic errors. Conversely, DNA replication stress and mitotic checkpoints rarely undergo mutations because any aberrant activity could result in irreparable damage or catastrophic chromosomal missegregation, leading to cancer cell death. This review focuses on the checkpoint signaling mechanisms involved in cancer cells and how an emerging understanding of these pathways can provide new therapeutic opportunities for cancer therapy.

Targeting cyclin-dependent kinase 2 (CDK2) interactions with cyclins and Speedy 1 (Spy1) for cancer and male contraception

The review discusses progress in discovering cyclin-dependent kinase 2 (CDK2) inhibitors for cancer treatment and their potential for male contraception. It summarizes first-, second-, and third-generation CDK inhibitors and selective CDK2 inhibitors currently in clinical trials for cancer. Novel strategies to discover allosteric inhibitors, covalent inhibitors, and degraders are also discussed.

Biological Activity of Peptide Fraction Derived from Hermetia illucens L. (Diptera: Stratiomyidae) Larvae Haemolymph on Gastric Cancer Cells

Gastric cancer (GC) is one of the leading causes of cancer-related mortality worldwide, characterised by poor prognosis and limited responsiveness to chemotherapy. There is a need for new and more effective anticancer agents. Antimicrobial peptides (AMPs) represent a promising class of biomolecules for this purpose. Naturally occurring in the innate immune system, these peptides can also exert cytotoxic effects against cancer cells, earning them the designation of "anticancer peptides" (ACPs). They have the potential to be a viable support for current chemotherapy schedules due to their selectivity against cancer cells and minor propensity to induce chemoresistance in cells. Insects are an excellent source of AMPs. Among them, due to its ability to thrive in hostile and microorganism-rich environments, we isolated a peptide fraction from Hermetia illucens L. (Diptera: Stratiomyidae) haemolymph to evaluate a possible anticancer activity. We tested Peptide Fractions (PFs) against AGS and KATO III gastric cancer cell lines. Data obtained indicated that PFs, especially those resulting from Escherichia coli and Micrococcus flavus infection (to boost immune response), were able to inhibit tumour cell growth by inducing apoptosis or cell cycle arrest in a cell line-specific manner. These results support further investigation into the use of antimicrobial peptides produced from insects as possible anticancer agents.

The Role of the Fox Gene in Breast Cancer Progression

Forkhead box (FOX) genes are a family of transcription factors that participate in many biological activities, from early embryogenesis to the formation of organs, and from regulation of glucose metabolism to regulation of longevity. Given the extensive influence in the multicellular process, FOX family proteins are responsible for the progression of many types of cancers, especially lung cancer, breast cancer, prostate cancer, and other cancers. Breast cancer is the most common cancer among women, and 2.3 million women were diagnosed in 2020. So, various drugs targeting the FOX signaling pathway have been developed to inhibit breast cancer progression. While the role of the FOX family gene in cancer development has not received enough attention, discovering more potential drugs targeting the FOX signaling pathway is urgently demanded. Here, we review the main members in the FOX gene family and summarize their signaling pathway, including the regulation of the FOX genes and their effects on breast cancer progression. We hope this review will emphasize the understanding of the role of the FOX gene in breast cancer and inspire the discovery of effective anti-breast cancer medicines targeting the FOX gene in the future.

Molecular biomarkers of progression in non-muscle-invasive bladder cancer - beyond conventional risk stratification

The global incidence of bladder cancer is more than half a million diagnoses each year. Bladder cancer can be categorized into non-muscle-invasive bladder cancer (NMIBC), which accounts for ~75% of diagnoses, and muscle-invasive bladder cancer (MIBC). Up to 45% of patients with NMIBC develop disease progression to MIBC, which is associated with a poor outcome, highlighting a clinical need to identify these patients. Current risk stratification has a prognostic value, but relies solely on clinicopathological parameters that might not fully capture the complexity of disease progression. Molecular research has led to identification of multiple crucial players involved in NMIBC progression. Identified biomarkers of progression are related to cell cycle, MAPK pathways, apoptosis, tumour microenvironment, chromatin stability and DNA-damage response. However, none of these biomarkers has been prospectively validated. Reported gene signatures of progression do not improve NMIBC risk stratification. Molecular subtypes of NMIBC have improved our understanding of NMIBC progression, but these subtypes are currently unsuitable for clinical implementation owing to a lack of prospective validation, limited predictive value as a result of intratumour subtype heterogeneity, technical challenges, costs and turnaround time. Future steps include the development of consensus molecular NMIBC subtypes that might improve conventional clinicopathological risk stratification. Prospective implementation studies of biomarkers and the design of biomarker-guided clinical trials are required for the integration of molecular biomarkers into clinical practice.

oar-miR-411a-5p Promotes Proliferation and Differentiation in Hu Sheep Myoblasts Under Heat Stress by Targeting SMAD2

MicroRNAs (miRNAs) are endogenous noncoding RNAs that produce a remarked effect on regulating posttranscriptional gene expression. Our previous study identified a decrease in the expression of oar-miR-411a-5p from umbilical plasma in intrauterine growth restriction (IUGR) Hu lambs subjected to maternal heat stress. In this study, we demonstrated that oar-miR-411a-5p could modulate skeletal muscle development. Overexpression of oar-miR-411a-5p significantly enhanced proliferation and differentiation in heat-stressed Hu sheep myoblasts while suppressing apoptosis. Conversely, inhibition of oar-miR-411a-5p resulted in opposing effects. Subsequently, RNAhybrid analysis revealed targeted sites between oar-miR-411a-5p and the 3' untranslated region (UTR) of SMAD2. This suggested that SMAD2 is a direct target gene of oar-miR-411a-5p, as its expression was negatively modulated by oar-miR-411a-5p, a finding corroborated by dual-luciferase assay and RT-qPCR. Furthermore, co-transfection of oar-miR-411a-5p and SMAD2 into Hu sheep myoblasts indicated that oar-miR-411a-5p modulated heat-stressed myoblast growth by targeting SMAD2. In conclusion, these findings elucidate the function of oar-miR-411a-5p in promoting the development of heat-stressed Hu sheep myoblasts, thereby enhancing our understanding of how miRNAs influence skeletal muscle growth in heat-stressed Hu sheep.

Hyperoxia shows duration-dependent effects on the lengths of cell cycle phases in fetal cortical neural stem cells

Fetal neural stem cells (NSCs) physiologically reside under low-oxygen conditions (1%-5% of tissue pO2), but are often transferred and maintained under atmospheric oxygen levels of 21% pO2 (hyperoxia) for in vitro investigations. These altered oxygen conditions lead to adaptive changes in NSCs which complicate the interpretation of in vitro data. However, the underlying adaption dynamics remain largely enigmatic. Here we investigated short-term hyperoxia effects (5 days in 3% pO2 followed by 2 days in 21% pO2) in comparison to continuous hyperoxia effects (7 days in 21% pO2) and physioxic control (7 days in 3% pO2). We utilized cortical NSCs to analyze the cell cycle phases by flow cytometry and cumulative BrdU incorporation assay. NSCs showed a severe reduction of cell proliferation when cultivated under continuous hyperoxia, but no changes after short-term hyperoxia. Subsequent cell cycle analysis as assessed by flow cytometry revealed a clear shift of NSCs from G0/G1-phase towards S- or G2/M-phase after both continuous and short-term hyperoxia. However, while cell cycle length was dramatically reduced by short-term hyperoxia, it was increased during continuous hyperoxia. Taken together, our results demonstrate the beneficial effect of physioxia for expanding NSCs in vitro and reveal differential effects of short-term hyperoxia compared to continuous hyperoxia.

Optimizing therapeutic approaches for HR+/HER2- advanced breast cancer: clinical perspectives on biomarkers and treatment strategies post-CDK4/6 inhibitor progression

This review offers an expert perspective on biomarkers, CDK4/6 inhibitor efficacy, and therapeutic approaches for managing hormone receptor-positive (HR+), human epidermal growth factor receptor-negative (HER2-) advanced breast cancer (ABC), particularly after CDK4/6 inhibitor progression. Key trials have demonstrated that combining CDK4/6 inhibitors with endocrine therapy (ET) significantly improves progression-free survival (PFS), with median durations ranging from 14.8 to 26.7 months, and overall survival (OS), with median durations reaching up to 53.7 months. Actionable biomarkers, such as PIK3CA and ESR1 mutations, have emerged as pivotal tools to guide second-line treatment decisions, enabling the use of targeted therapies like alpelisib and elacestrant and emphasizing the important role of biomarkers in guiding the selection of therapy. This overview aims to provide clinicians with a practical and up-to-date framework to inform treatment decisions and improve patient care in the context of this challenging disease. Additionally, we review emerging biomarkers and novel treatment strategies to address this difficult clinical landscape.

Nanomaterials exert biological effects by influencing the ubiquitin-proteasome system

The ubiquitin-proteasome system (UPS) is an important type of protein post-translational modification that affects the quantity and quality of various proteins and influences cellular processes such as the cell cycle, transcription, oxidative stress, and autophagy. Nanomaterials (NMs), which exhibit excellent physicochemical properties, can directly interact with the UPS and act as molecular-targeted drugs to induce changes in biological processes. This review provides an overview of the influence of NMs on the UPS of misfolded proteins and key proteins, which are related to cancer, neurodegenerative diseases and oxidative stress. This review also summarizes the role of modification processes involved in ubiquitination the biological effects of NMs and the mechanism of such effects of NMs through regulation of the UPS. This review deepens our understanding of the influence of NMs on the protein degradation process and provides new potential therapeutic targets for disease.

Cyclin-dependent protein kinases and cell cycle regulation in biology and disease

Cyclin Dependent Kinases (CDKs) are closely connected to the regulation of cell cycle progression, having been first identified as the kinases able to drive cell division. In reality, the human genome contains 20 different CDKs, which can be divided in at least three different sub-family with different functions, mechanisms of regulation, expression patterns and subcellular localization. Most of these kinases play fundamental roles the normal physiology of eucaryotic cells; therefore, their deregulation is associated with the onset and/or progression of multiple human disease including but not limited to neoplastic and neurodegenerative conditions. Here, we describe the functions of CDKs, categorized into the three main functional groups in which they are classified, highlighting the most relevant pathways that drive their expression and functions. We then discuss the potential roles and deregulation of CDKs in human pathologies, with a particular focus on cancer, the human disease in which CDKs have been most extensively studied and explored as therapeutic targets. Finally, we discuss how CDKs inhibitors have become standard therapies in selected human cancers and propose novel ways of investigation to export their targeting from cancer to other relevant chronic diseases. We hope that the effort we made in collecting all available information on both the prominent and lesser-known CDK family members will help in identify and develop novel areas of research to improve the lives of patients affected by debilitating chronic diseases.

Cyclin E1/CDK2 activation defines a key vulnerability to WEE1 kinase inhibition in gynecological cancers

Upregulation of Cyclin E1 and subsequent activation of CDK2 accelerates cell cycle progression from G1 to S phase and is a common oncogenic driver in gynecological malignancies. WEE1 kinase counteracts the effects of Cyclin E1/CDK2 activation by regulating multiple cell cycle checkpoints. Here we characterized the relationship between Cyclin E1/CDK2 activation and sensitivity to the selective WEE1 inhibitor azenosertib. We found that ovarian cancer cell lines with high levels of endogenous Cyclin E1 expression or forced overexpression were exquisitely sensitive to azenosertib and these results extended to in vivo models of ovarian and uterine serous carcinoma. Models with high Cyclin E1 expression showed higher baseline levels of replication stress and enhanced cellular responses to azenosertib treatment. We found azenosertib synergized with different classes of chemotherapy and described distinct underlying mechanisms. Finally, we provided early evidence from an ongoing phase I study demonstrating the clinical activity of monotherapy azenosertib in patients with Cyclin E1/CDK2-activated ovarian and uterine serous carcinomas.

Effects of Low Dose Neutron-Gamma Field on Cell Cycle and Damage of Human Lymphocytes

Purpose: The aim is to investigate the response of peripheral blood lymphocytes to a low-dose neutron-gamma field. Methods: The human peripheral blood was exposed to low-dose neutron-gamma radiation ex vivo. Flow cytometry was utilized to evaluate the changes in cell cycle and protein levels of p21, CDK2, and γH2AX. qPCR analysis was conducted to investigate the mRNA transcription of p21 and CDK2. The chromosomes aberration and micronucleus rate in peripheral blood lymphocytes were observed by microscope. Results: Within the radiation dose range of 0-5976 μGy, compared to the "0" dose group, there was an increase in the proportion of cells in G1 phase and a decrease in the proportion of cells in G2 phase. Additionally, there was an upregulation of p21 and γH2AX protein expression, a downregulation of CDK2 protein expression, and an increase in transcription levels of p21 and CDK2 mRNA. Furthermore, there was an elevation in the rate of chromosome aberrations in peripheral blood lymphocytes; however, no significant change of micronuclei rate was observed. Conclusions: The response of human lymphocytes to low dose neutron gamma irradiation can be reflected by the changes of cell cycle, chromosome aberration and RPS18 expression.

Tri-o-tolyl phosphate impedes implantation: Malfunction of mitochondria and disruption of calcium homeostasis through MAPK and AKT signaling cascades

Tri-o-tolyl phosphate (TOTP), a flame retardant containing aryl compounds, is widely used in human living environments owing to its several applications. However, Due to the overuse of TOTP, its residue has been identified in various environments and non-targeted organisms, including humans. Although extensive research is being conducted to address the toxicity of this substance, its potential reproductive toxicity in females has not been sufficiently studied. In this study, human HTR-8/SVneo and JEG-3 trophoblasts were used to investigate the effects of TOTP on implantation. Results showed that TOTP decreased cell viability and inhibited cell proliferation by triggering cell cycle arrest. It also induced apoptosis and mitochondrial dysfunction, disrupted calcium homeostasis, increased the influx of calcium ions into the mitochondria, and disturbed cell aggregation and migration. Moreover, the MAPK and AKT cell signaling pathways were altered, and crosstalk between these pathways were distinguished. Thus, inhibitors of the MAPK and AKT pathways exhibited potential for managing the toxicity of TOTP. Overall, this study demonstrated the reproductive toxicity of TOTP in human females and elucidated the underlying mechanisms. Our results highlighted the potential risks associated with TOTP.

Silencing of ERRα gene represses cell proliferation and induces apoptosis in human skin fibroblasts

Estrogen‑related receptor (ERR) is an orphan nuclear receptor structurally akin to the estrogen receptor. ERR is expressed in tissues with active energy metabolism and regulates intracellular metabolic functions. Additionally, ERRs are known to be strongly expressed in the epidermis of skin tissue, but their functions are unknown. The present study investigated the function of ERRα in human skin fibroblasts. ERRα expressed in human dermal fibroblast TIG113 was knocked down using small interfering (si)RNA and gene expression was comprehensively analyzed using microarrays 48 h later. Pathway analysis was performed using Wikipathways on genes exhibiting expression changes of ≥1.5‑fold. Expression of cell cycle‑related and apoptosis‑related genes was compared using reverse transcription‑quantitative PCR. After treating TIG113 cells with siERRα for 72 h, cell proliferation was assessed using the Cell Counting Kit‑8 or a scratch wound healing assay and apoptotic cells were measured using the Poly Caspase Assay Kit. Cell cycle analysis was performed using flow cytometry. The expression of the ERRα gene was suppressed by siRNA. The expression of genes associated with cell cycle‑related pathways were decreased while that of those associated with apoptosis‑related pathways increased. Furthermore, the expression of cell cycle‑related genes such as cell division cycle 25C, cyclin E and cyclin B1 was decreased and the expression of apoptosis‑related genes such as caspase3 and Fas cell surface death receptor was increased. Cell proliferation was suppressed and the number of apoptotic cells increased ~2‑fold in ERRα‑knockdown TIG113 cells. Cell cycle analysis revealed that the number of cells in the Sub‑G1 phase increased and that in the S and G2/M phases decreased. The present study suggested that ERRα is an essential for the survival of human skin fibroblasts.

ELF3 Overexpression Contributes to the Malignant Transformation of HPV16 E6/E7-Immortalized Keratinocytes by Promoting CCNE2 Expression

Current cancer burden caused by persistent infection with human papillomaviruse genotype 16 (HPV16) cannot be ignored. The related mechanisms of oncoproteins E6 and E7 from HPV16 on keratinocyte malignant transformation need to be further elucidated. GSE3292 dataset analysis revealed the upregulation of ETS transcription factor 3 (ELF3) and cyclin E2 (CCNE2). To verify whether there is an interaction between ELF3 and CCNE2, E74 like ELF3 and CCNE2 expression profiles as well as their putative binding sites were analyzed using bioinformatics. Retroviruses encoding HPV16 E6 and E7 genes were used to induce immortalization of human foreskin keratinocytes (HFKs) in vitro. Dual luciferase reporters assay was used to verify the binding of ELF3 and CCNE2. The effect of ELF3 on the immortalized cells was investigated using CCK-8 assay, cell cycle analysis and western blot. ELF3 and CCNE2 presented overexpression patterns in head and neck squamous cell carcinoma. HPV16 E6/E7-expressing HFKs showed enhanced viability, accelerated cell cycle as well as upregulated ELF3 and CCNE2. ELF3 overexpression enhanced the activity of CCNE2 promoter. ELF3 silencing reduced viability, induced cell cycle arrest and suppressed expressions of CCNE2, E6 and E7 in HPV16 E6/E7-expressing HFKs. Downregulation of ELF3 played an inhibiting role in the malignant transformation of HPV16 E6/E7-immortalized HFKs by decreasing CCNE2 expression.

Cyclin-dependent kinases (CDKs) are key genes regulating early development of Neptunea arthritica cumingii: evidence from comparative transcriptome and proteome analyses

In this study, we applied comparative transcriptomics and proteomics techniques to systematically investigate the dynamic expression patterns of genes and proteins at various stages of early embryonic development of the gastropod Neptunea arthritica cumingii. Twelve cyclin-dependent kinase (CDKs) genes and five downstream proteins associated with these CDKs were identified. Through techniques such as qRT-PCR, our data elucidate for the first time the regulatory functions of CDK family genes and establish CDKs as a pivotal gene cluster in the early embryonic development of N. cumingii. These findings not only enhance the understanding of molecular developmental biology in N. cumingii and marine gastropods in general but also provide significant insights into the mechanisms involved in early embryonic development in N. cumingii. Furthermore, our results provide theoretical guidance for advancing artificial breeding technology for N. cumingii.

Actinomycin D and bortezomib disrupt protein homeostasis in Wilms tumor

Wilms tumor is the most common kidney cancer in children, and diffuse anaplastic Wilms tumor is the most chemoresistant histological subtype. Here, we explore how Wilms tumor cells evade the common chemotherapeutic drug actinomycin D, which inhibits ribosomal RNA biogenesis. Using ribosome profiling, protein arrays, and a genome-wide knockout screen, we describe how actinomycin D disrupts protein homeostasis and blocks cell cycle progression. We found that, when ribosomal capacity is limited by actinomycin D treatment, anaplastic Wilms tumor cells preferentially translate proteasome components and upregulate proteasome activity. Based on these findings, we tested whether the proteasome inhibitor bortezomib sensitizes cells to actinomycin D treatment. Indeed, we found that the combination induces apoptosis both in vitro and in vivo and prolongs survival in xenograft models. Lastly, we show that increased levels of proteasome components are associated with anaplastic histology and worse prognosis in Wilms tumor patients. In sum, maintaining protein homeostasis is critical for Wilms tumor proliferation, and it can be therapeutically disrupted by blocking protein synthesis or turnover.

SOX2 control activation of dormant prostate cancer cells in bone metastases by promoting CCNE2 gene expression

BACKGROUND

Cancer stem cells (CSCs) have a powerful tumor initiation ability, which can promote the early dissemination of single disseminated tumor cells (DTCs), leading to tumor progression. SOX2, a pluripotent inducible transcription factor, is key to maintaining self-renewal and pluripotency of prostate cancer stem cells. However, there is a lack of comprehensive understanding of how SOX2 regulates DTCs dormancy and proliferation in the bone marrow microenvironment.

METHODS AND RESULTS

By constructing a mouse bone metastasis model to simulate the progression of prostate cancer with bone metastasis, the bone tissue immunofluorescence showed that SOX2 expression increased with the progression of prostate cancer in the bone marrow microenvironment. We validated this phenomenon with publicly available single-cell and transcriptome datasets and found that SOX2 is involved in multiple phenotypes associated with prostate cancer dormancy, proliferation, and invasion. Further, CCNE2, a potential target downstream of SOX2, was identified through multiple transcription factor databases and protein interaction networks.

CONCLUSION

The expression of SOX2 affects multiple phenotypes related to dormancy, proliferation and invasion of prostate cancer, and may indirectly activate the dormant prostate cancer cells through the downstream target gene CCNE2, thus affecting the progression and bone metastasis of prostate cancer.

Convergent Evolution Associated with the Loss of Developmental Diapause May Promote Extended Lifespan in Bees

Diapause has long been proposed to play a significant role in the evolution of eusociality in Hymenoptera. Recent studies have shown that shifts in the diapause stage precede social evolution in wasps and bees; however, the genomic basis remains unknown. Given the overlap in molecular pathways that regulate diapause and lifespan, we hypothesized that the evolutionary loss of developmental diapause may lead to extended lifespan among adults, which is a prerequisite for the evolution of eusociality. To test whether the loss of prepupal diapause is followed by genomic changes associated with lifespan extension, we compared 27 bee genomes with or without prepupal diapause. Our results point to several potential mechanisms for lifespan extension in species lacking prepupal diapause, including the loss of the growth hormone PTTH and its receptor TORSO, along with convergent selection in genes known to regulate lifespan in animals. Specifically, we observed purifying selection of prolongevity genes and relaxed selection of antilongevity genes within the IIS/TOR pathway in species that have lost prepupal diapause. Changes in selection pressures on this pathway may lead to the evolution of new phenotypes, such as lifespan extension and altered responses to nutritional signals that are crucial for social evolution.

Long Non-Coding RNA LINC01116 Promotes the Proliferation of Lung Adenocarcinoma by Targeting miR-9-5p/CCNE1 Axis

Long non-coding RNA (lncRNA) LINC01116 is crucial in promoting cell proliferation, invasion and migration in solid tumours, including lung adenocarcinoma (LUAD). LINC01116 acts as a competing endogenous RNAs (ceRNA) that binds competitively to microRNAs and plays a critical role in tumour migration and invasion. However, other mechanisms of action besides the ceRNA theory have been rarely reported and remain to be elucidated further. The differences in RNA and protein levels in cells and tissues were assessed through real-time quantitative PCR and Western blot analysis. In vitro functional assays and in vivo xenograft models were used to analyse the function of LINC01116 in LUAD. Thus, the molecular correlation between miR-9-5p and CCNE1 was investigated through direct and indirect mechanism experiments. LINC01116, miR-9-5p and CCNE1 were upregulated in LUAD cell lines and tissues and were associated with a poor prognosis in patients. LINC01116 depletion inhibited proliferation but facilitated cell apoptosis. AGO2-RNA binding protein immunoprecipitation (AGO2-RIP) experiments confirmed that AGO2 binds to LINC01116 and miR-9-5p, indicating that LINC01116 interacts with miR-9-5p. The overexpression of miR-9-5p and CCNE1 effectively counteracts the biological effects of LINC01116 knockdown on reduced proliferation and cell cycle arrest in LUAD cells. The downregulation of miR-9-5p significantly reduces the CCNE1 level in A549 cells, and the upregulation of LINC01116 counteracts the downregulation of miR-9-5p effect, restoring the expression level of CCNE1. Our data demonstrated that LINC01116 regulates the expression of CCNE1 by positively regulating miR-9-5p, thereby affecting cell cycle, proliferation and participating in the development of LUAD.

CDK14 is regulated by IGF2BP2 and involved in osteogenic differentiation via Wnt/β-catenin signaling pathway in vitro

AIMS

Cyclin-dependent kinase (CDK) family proteins involve in various cellular processes via regulating the cell cycle; however, their expression during osteogenic differentiation and postmenopausal osteoporosis remains poorly understood.

MAIN METHODS

Using bioinformatics, we screened for CDK14 bound to Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and explored its expression in vitro with time-gradient model and in a mouse model of postmenopausal osteoporosis, building on prior research. Subsequently, we investigated its effect on osteoblast proliferation, cell cycle dynamics, and osteogenic differentiation by administering CDK14 siRNA and the covalent inhibitor FMF-04-159-2. Furthermore, we examined the interaction between IGF2BP2 and CDK14. Finally, we validated the regulatory role of CDK14 on the Wnt/β-catenin pathway.

KEY FINDINGS

Our findings demonstrate a time-dependent CDK14 expression patterns during osteogenic differentiation of MC3T3-E1 cell line, with an initial increase followed by gradual decline over time. Notably, CDK14 expression exhibited significant reduction in bone tissue of postmenopausal osteoporosis mouse model. CDK14 inhibition altered osteoblast cell cycle dynamics, significantly reduced cellular proliferation capacity, and impaired osteogenic differentiation ability. IGF2BP2 interacted with CDK14 mRNA, and stabilizing mRNA's structure and inhibiting its degradation. Additionally, CDK14 facilitated Low-density lipoprotein receptor-related protein 6 (LRP6) and Glycogen synthase kinase 3β (GSK3β) phosphorylation, thus regulating β-catenin levels.

SIGNIFICANCE

These findings provide further insight into the molecular mechanisms governing osteoblast proliferation, differentiation and osteoporosis.

COL8A2 activation enhances function of corneal endothelial cells through HIPPO signaling/mitochondria pathway

Corneal endothelial cells (CECs) are essential for maintaining corneal transparency and hydration through their barrier and pump functions. The COL8A2 gene encodes a component of the extracellular matrix of the cornea, which is crucial for the normal functioning of these cells. Mutations in COL8A2 are linked to corneal dystrophies, emphasizing the gene's importance in corneal health. The purpose of this research is to explore the effects of COL8A2 activation within CECs, to understand its contribution to cellular behavior and health. COL8A2 CRISPR/dCas9 activation system (aCOL8A2) was used to activate the COL8A2. In rats, wound healing and mitochondrial function were assessed after COL8A2 activation. As a result, aCOL8A2 promoted wound healing of rat corneal endothelium by increasing mitochondrial membrane potential. In cultured human CECs, proteomic analysis was performed to screen and identify the differential protein profiles between control and aCOL8A2 cells. Western blot was used to validate the differential proteins from both cells. Mitochondrial function and intracellular distribution were assessed by measuring ATP production and mitochondrial membrane potential. In cultured human CECs, aCOL8A2 increased COL8A2 and phospho-YAP levels. Transendothelial electrical resistance (TEER) was increased and actin cytoskeleton was attenuated by aCOL8A2. Gene ontology analysis revealed that the proteins were mainly involved in the regulation of folate biosynthesis, ECM-receptor interaction, cell differentiation, NADP activity and cytoskeleton. ATP production was increased, mitochondrial membrane potential was polarized and mitochondrial distribution was widespread in the aCOL8A2 group. In conclusion, aCOL8A2 induces a regulatory cascade affecting mitochondrial positioning and efficiency, mediated by alterations in the cytoskeletal architecture and the YAP signaling pathway. This sequence of events serves to bolster the functional capacities of corneal endothelial cells, including their pump and barrier functions, essential for corneal health and transparency.