Melanoma progression and prognostic models drawn from single-cell, spatial maps of benign and malignant tumors.

Melanoma clinical outcomes emerge from incompletely understood genetic mechanisms operating within the tumor and its microenvironment. Here, we used single-cell RNA-based spatial molecular imaging (RNA-SMI) in patient-derived archival tumors to reveal clinically relevant markers of malignancy progression and prognosis. We examined spatial gene expression of 203,472 cells inside benign and malignant melanocytic neoplasms, including melanocytic nevi and primary invasive and metastatic melanomas. Algorithmic cell clustering paired with intratumoral comparative two-dimensional analyses visualized synergistic, spatial gene signatures linking cellular proliferation, metabolism, and malignancy, validated by protein expression. Metastatic niches included up-regulation of CDK2 and FABP5, which independently predicted poor clinical outcome in 473 patients with melanoma via Cox regression analysis. More generally, our work demonstrates a framework for applying single-cell RNA-SMI technology toward identifying gene regulatory landscapes pertinent to cancer progression and patient survival.

Vitamin D Receptor Regulates Liver Regeneration After Partial Hepatectomy in Male Mice.

Vitamin D signals through the vitamin D receptor (VDR) to induce its end-organ effects. Hepatic stellate cells control development of liver fibrosis in response to stressors and vitamin D signaling decreases fibrogenesis. VDR expression in hepatocytes is low in healthy liver, and the role of VDR in hepatocyte proliferation is unclear. Hepatocyte-VDR null mice (hVDR) were used to assess the role of VDR and vitamin D signaling in hepatic regeneration. hVDR mice have impaired liver regeneration and impaired hepatocyte proliferation associated with significant differential changes in bile salts. Notably, mice lacking hepatocyte VDR had significant increases in expression of conjugated bile acids after partial hepatectomy, consistent with failure to normalize hepatic function by the 14-day time point tested. Real-time PCR of hVDR and control livers showed significant changes in expression of cell-cycle genes including cyclins D1 and E1 and cyclin-dependent kinase 2. Gene expression profiling of hepatocytes treated with vitamin D or control showed regulation of groups of genes involved in liver proliferation, hepatitis, liver hyperplasia/hyperproliferation, and liver necrosis/cell death. Together, these studies demonstrate an important functional role for VDR in hepatocytes during liver regeneration. Combined with the known profibrotic effects of impaired VDR signaling in stellate cells, the studies provide a mechanism whereby vitamin D deficiency would both reduce hepatocyte proliferation and permit fibrosis, leading to significant liver compromise.

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.

Molecular docking and MD simulation studies of 4-thiazol-N-(pyridin-2-yl)pyrimidin-2-amine derivatives as novel inhibitors targeted to CDK2/4/6.

PURPOSE: Nowadays, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have been approved for treating metastatic breast cancer and have achieved inspiring curative effects. But some discoveries have indicated that CDK 4/6 are not the requisite factors in some cell types because CDK2 partly compensates for the inhibition of CDK4/6. Thus, it is urgent to design CDK2/4/6 inhibitors for significantly enhancing their potency. This study aims to explore the mechanism of the binding of CDK2/4/6 kinases and their inhibitors to design novel CDK2/4/6 inhibitors for significantly enhancing their potency in different kinds of cancers. MATERIALS AND METHODS: A series of 72 disparately functionalized 4-substituted N-phenylpyrimidin-2-amine derivatives exhibiting potent inhibitor activities against CDK2, CDK4 and CDK6 were collected to apply to this research. The total set of these derivatives was divided into a training set (54 compounds) and a test set (18 compounds). The derivatives were constructed through the sketch molecule module in SYBYL 6.9 software. A Powell gradient algorithm and Tripos force field were used to calculate the minimal structural energy and the minimized structure was used as the initial conformation for molecular docking. By the means of 3D-QSAR models, partial least squares (PLS) analysis, molecular dynamics (MD) simulations and binding free energy calculations, we can find the relationship between structure and biological activity. RESULTS: In this study, we used molecular docking, 3D-QSAR and molecular dynamics simulation methods to comprehensively analyze the interaction and structure-activity relationships of 72 new CDK2/4/6 inhibitors. We used detailed statistical data to reasonably verify the constructed 3D-QSAR models for three receptors (q2 of CDK2 = 0.714, R2pred = 0.764, q2 = 0.815; R2pred of CDK4 = 0.681, q2 = 0.757; R2pred of CDK6 = 0.674). MD simulations and decomposition energy analysis validated the reasonability of the docking results and identified polar interactions as crucial factors that influence the different bioactivities of the studied inhibitors of CDK2/4/6 receptors, especially the electrostatic interactions of Lys33/35/43 and Asp145/158/163. The nonpolar interaction with Ile10/12/19 was also critical for the differing potencies of the CDK2/4/6 inhibitors. We concluded that the following probably enhanced the bioactivity against CDK2/4/6 kinases: (1) electronegative groups at the N1-position and electropositive and moderate-sized groups at ring E; (2) electrogroups featured at R2; (3) carbon atoms at the X-position or ring C replaced by a benzene ring; and (4) an electrogroup as R4. CONCLUSION: Previous studies, to our knowledge, only utilized a single approach of 3D-QSAR and did not integrate this method with other sophisticated techniques such as molecular dynamics simulations to discover new potential inhibitors of CDK2, CDK4, or CDK6. So we applied the intergenerational technology, such as 3D-QSAR technology, molecular docking simulation techniques, molecular dynamics simulations and MMPBSA19/MMGBSA20-binding free energy calculations to statistically explore the correlations between the structure with biological activities. The constructed 3D-QSAR models of the three receptors were reasonable and confirmed by the excellent statistical data. We hope the results obtained from this work will provide some useful references for the development of novel CDK2/4/6 inhibitors.

An intermediate Rb-E2F activity state safeguards proliferation commitment.

Tissue repair, immune defence and cancer progression rely on a vital cellular decision between quiescence and proliferation1,2. Mammalian cells proliferate by triggering a positive feedback mechanism3,4. The transcription factor E2F activates cyclin-dependent kinase 2 (CDK2), which in turn phosphorylates and inactivates the E2F inhibitor protein retinoblastoma (Rb). This action further increases E2F activity to express genes needed for proliferation. Given that positive feedback can inadvertently amplify small signals, understanding how cells keep this positive feedback in check remains a puzzle. Here we measured E2F and CDK2 signal changes in single cells and found that the positive feedback mechanism engages only late in G1 phase. Cells spend variable and often extended times in a reversible state of intermediate E2F activity before committing to proliferate. This intermediate E2F activity is proportional to the amount of phosphorylation of a conserved T373 residue in Rb that is mediated by CDK2 or CDK4/CDK6. Such T373-phosphorylated Rb remains bound on chromatin but dissociates from it once Rb is hyperphosphorylated at many sites, which fully activates E2F. The preferential initial phosphorylation of T373 can be explained by its relatively slower rate of dephosphorylation. Together, our study identifies a primed state of intermediate E2F activation whereby cells sense external and internal signals and decide whether to reverse and exit to quiescence or trigger the positive feedback mechanism that initiates cell proliferation.

Clinicopathological Significance of Cyclin-Dependent Kinase 2 (CDK2) in Ductal Carcinoma In Situ and Early-Stage Invasive Breast Cancers.

Cyclin-dependent kinase 2 (CDK2) is a key cell cycle regulator, with essential roles during G1/S transition. The clinicopathological significance of CDK2 in ductal carcinomas in situ (DCIS) and early-stage invasive breast cancers (BCs) remains largely unknown. Here, we evaluated CDK2's protein expression in 479 BC samples and 216 DCIS specimens. Analysis of CDK2 transcripts was completed in the METABRIC cohort (n = 1980) and TCGA cohort (n = 1090), respectively. A high nuclear CDK2 protein expression was significantly associated with aggressive phenotypes, including a high tumour grade, lymph vascular invasion, a poor Nottingham prognostic index (all p-values < 0.0001), and shorter survival (p = 0.006), especially in luminal BC (p = 0.009). In p53-mutant BC, high nuclear CDK2 remained linked with worse survival (p = 0.01). In DCIS, high nuclear/low cytoplasmic co-expression showed significant association with a high tumour grade (p = 0.043), triple-negative and HER2-enriched molecular subtypes (p = 0.01), Comedo necrosis (p = 0.024), negative ER status (p = 0.004), negative PR status (p < 0.0001), and a high proliferation index (p < 0.0001). Tumours with high CDK2 transcripts were more likely to have higher expressions of genes involved in the cell cycle, homologous recombination, and p53 signaling. We provide compelling evidence that high CDK2 is a feature of aggressive breast cancers. The clinical evaluation of CDK2 inhibitors in early-stage BC patients will have a clinical impact.

Molecular docking approach for the design and synthesis of new pyrazolopyrimidine analogs of roscovitine as potential CDK2 inhibitors endowed with pronounced anticancer activity.

Cyclin-dependent kinase 2 (CDK2) is a vital protein for controlling cell cycle progression that is critically associated with various malignancies and its inhibition could offer a convenient therapeutic approach in designing anticancer remedies. Consequently, this study aimed to design and synthesize new CDK2 inhibitors featuring roscovitine as a template model. The purine ring of roscovitine was bioisosterically replaced with the pyrazolo[3,4-d]pyrimidine scaffold, in addition to some modifications in the side chains. A preliminary molecular docking study for the target chemotypes in the CDK2 binding domain revealed their ability to accomplish similar binding patterns and interactions to that of the lead compound roscovitine. Afterwards, synthesis of the new derivatives was accomplished. Then, the initial anticancer screening at a single dose by the NCI revealed that compounds 7a, 9c, 11c, 17a and 17b achieved the highest GI% values reaching up to 150 % indicating their remarkable activity. These derivatives were subsequently selected to undertake five-dose testing, where compounds 7a, 9c, 11c and 17a unveiled the most pronounced activity against almost the full panel with GI50 ranges; 1.41-28.2, 0.116-2.39, 0.578-60.6 and 1.75-42.4 µM, respectively and full panel GI50 (MG-MID); 8.24, 0.6, 2.46 and 6.84 µM, respectively. CDK2 inhibition assay presented compounds 7a and 9c as the most potent inhibitors with IC50 values of 0.262 and 0.281 µM, respectively which are nearly 2.4 folds higher than the reference ligand roscovitine (IC50 = 0.641 µM). Besides, flow cytometric analysis on the most susceptible and safe cell lines depicted that 7a caused cell cycle arrest at G1/S phase in renal cancer cell line (RXF393) while 9c led to cell growth arrest at S phase in breast cancer cell line (T-47D) along with pronounced apoptotic induction in the mentioned cell lines. These findings afforded new anticancer pyrazolo[3,4-d]pyrimidine, roscovitine analogs, acting via CDK2 inhibition.

Exploring the mechanism of action of spirooxindoles as a class of CDK2 inhibitors: a structure-based computational approach.

Cyclin-dependent kinase 2 (CDK2) regulates cell cycle checkpoints in the synthesis and mitosis phases and plays a pivotal role in cancerous cell proliferation. The activation of CDK2, influenced by various protein signaling pathways, initiates the phosphorylation process. Due to its crucial role in carcinogenesis, CDK2 is a druggable hotspot target to suppress cancer cell proliferation. In this context, several studies have identified spirooxindoles as an effective class of CDK2 inhibitors. In the present study, three spirooxindoles (SOI1, SOI2, and SOI3) were studied to understand their inhibitory mechanism against CDK2 through a structure-based approach. Molecular docking and molecular dynamics (MD) simulations were performed to explore their interactions with CDK2 at the molecular level. The calculated binding free energy for the spirooxindole-based CDK2 inhibitors aligned well with experimental results regarding CDK2 inhibition. Energy decomposition (ED) analysis identified key binding residues, including I10, G11, T14, R36, F82, K89, L134, P155, T158, Y159, and T160, in the CDK2 active site and T-loop phosphorylation. Molecular mechanics (MM) energy was identified as the primary contributor to stabilizing inhibitor binding in the CDK2 protein structure. Furthermore, the analysis of binding affinity revealed that the inhibitor SOI1 binds more strongly to CDK2 compared to the other inhibitors under investigation. It demonstrated a robust interaction with the crucial residue T160 in the T-loop phosphorylation site, responsible for kinase activation. These insights into the inhibitory mechanism are anticipated to contribute to the development of potential CDK2 inhibitors using the spirooxindole scaffold.

UHRF2 accumulates in early G1-phase after serum stimulation or mitotic exit to extend G1 and total cell cycle length.

Ubiquitin like with PHD and ring finger domains 2 (UHRF2) regulates the cell cycle and epigenetics as a multi-domain protein sharing homology with UHRF1. UHRF1 functions with DNMT1 to coordinate daughter strand methylation during DNA replication, but UHRF2 can't perform this function, and its roles during cell cycle progression are not well defined. UHRF2 role as an oncogene vs. tumor suppressor differs in distinct cell types. UHRF2 interacts with E2F1 to control Cyclin E1 (CCNE1) transcription. UHRF2 also functions in a reciprocal loop with Cyclin E/CDK2 during G1, first as a direct target of CDK2 phosphorylation, but also as an E3-ligase with direct activity toward both Cyclin E and Cyclin D. In this study, we demonstrate that UHRF2 is expressed in early G1 following either serum stimulation out of quiescence or in cells transiting directly out of M-phase, where UHRF2 protein is lost. Further, UHRF2 depletion in G2/M is reversed with a CDK1 specific inhibitor. UHRF2 controls expression levels of cyclins and CDK inhibitors and controls its own transcription in a negative-feedback loop. Deletion of UHRF2 using CRISPR/Cas9 caused a delay in passage through each cell cycle phase. UHRF2 loss culminated in elevated levels of cyclins but also the CDK inhibitor p27KIP1, which regulates G1 passage, to reduce retinoblastoma phosphorylation and increase the amount of time required to reach G1/S passage. Our data indicate that UHRF2 is a central regulator of cell-cycle pacing through its complex regulation of cell cycle gene expression and protein stability.

Smoking-induced CCNA2 expression promotes lung adenocarcinoma tumorigenesis by boosting AT2/AT2-like cell differentiation.

Lung adenocarcinoma (LUAD), a type of non-small cell lung cancer (NSCLC), originates from not only bronchial epithelial cells but also alveolar type 2 (AT2) cells, which could differentiate into AT2-like cells. AT2-like cells function as cancer stem cells (CSCs) of LUAD tumorigenesis to give rise to adenocarcinoma. However, the mechanism underlying AT2 cell differentiation into AT2-like cells in LUAD remains unknown. We analyze genes differentially expressed and genes with significantly different survival curves in LUAD, and the combination of these two analyses yields 147 differential genes, in which 14 differentially expressed genes were enriched in cell cycle pathway. We next analyze the protein levels of these genes in LUAD and find that Cyclin-A2 (CCNA2) is closely associated with LUAD tumorigenesis. Unexpectedly, high CCNA2 expression in LUAD is restrictedly associated with smoking and independent of other driver mutations. Single-cell sequencing analyses reveal that CCNA2 is predominantly involved in AT2-like cell differentiation, while inhibition of CCNA2 significantly reverses smoking-induced AT2-like cell differentiation. Mechanistically, CCNA2 binding to CDK2 phosphorylates the AXIN1 complex, which in turn induces ubiquitination-dependent degradation of ß-catenin and inhibits the WNT signaling pathway, thereby failing AT2 cell maintenance. These results uncover smoking-induced CCNA2 overexpression and subsequent WNT/ß-catenin signaling inactivation as a hitherto uncharacterized mechanism controlling AT2 cell differentiation and LUAD tumorigenesis.

[Effects of 4-hydroxy-2(3H)-benzoxazolone on proliferation and apoptosis of pancreatic cancer L3.6 cells].

This study explored the effects of 4-hydroxy-2(3H)-benzoxazolone(HBOA) on the proliferation and apoptosis of pancreatic cancer cells and its molecular mechanism. The L3.6 cells cultured in vitro were treated with HBOA of 0-1.0 mmol·L~(-1). The cell viability was detected by the cell counting kit-8(CCK-8) method, and the half inhibitory concentration(IC_(50)) was analyzed to determine the drug concentration and time. The cell morphology was observed under an inverted microscope and by acridine orange(AO) staining. The ability of proliferation and self-renewal were evaluated through live cell counting and colony formation experiments. The cell cycle progression and cell apoptosis rate were detected by flow cytometry. The morphology of cell apoptosis was observed by scanning electron microscopy. The mRNA expression of proliferating cell nuclear antigen(PCNA), cyclinA1, cyclinA2, cyclin dependent kinase 2(CDK2), and cyclin dependent kinase inhibitor 1A(P21) were determined by qPCR. The level of reactive oxygen species(ROS), lipid peroxide, and mitochondrial membrane potential were measured by flow cytometry. The activity of protein kinase B(Akt)/mammalian target of rapamycin(mTOR) signaling pathway was detected by Western blot. Compared with the control group, the cells treated with HBOA exhibited a significant decrease in viability. Then the optimal concentration and intervention time of HBOA were determined to be 0.4 mmol·L~(-1), 0.6 mmol·L~(-1), and 48 h. Compared with the control group, groups with HBOA of 0.4 mmol·L~(-1 )and 0.6 mmol·L~(-1) showed a significant suppression in cell proliferation and colony formation ability, down-regulated mRNA of PCNA, cyclinA1, cyclinA2, and CDK2, up-regulated P21 mRNA, S-phase cell cycle arrest, and increased cell apoptosis rate. There was an appearance of apoptotic bodies, increased ROS and lipid peroxide, decreased mitochondrial membrane potential(with a significant decrease in 0.6 mmol·L~(-1) group), and down-regulated p-Akt and p-mTOR proteins. The results show that HBOA inhibits the proliferation of pancreatic cancer L3.6 cells and induces cell apoptosis, which may be related to the increase in reactive oxygen species and the inhibition of the Akt/mTOR pathway.

Discovery of novel macrocyclic derivatives as potent and selective cyclin-dependent kinase 2 inhibitors.

Cyclin-dependent kinase 2 (CDK2) is a member of CDK family of kinases (CDKs) that regulate the cell cycle. Its inopportune or over-activation leads to uncontrolled cell cycle progression and drives numerous types of cancers, especially ovarian, uterine, gastric cancer, as well as those associated with amplified CCNE1 gene. However, developing selective lead compound as CDK2 inhibitors remains challenging owing to similarities in the ATP pockets among different CDKs. Herein, we described the optimization of compound 1, a novel macrocyclic inhibitor targeting CDK2/5/7/9, aiming to discover more selective and metabolically stable lead compound as CDK2 inhibitor. Molecular dynamic (MD) simulations were performed for compound 1 and 9 to gain insights into the improved selectivity against CDK5. Further optimization efforts led to compound 22, exhibiting excellent CDK2 inhibitory activity, good selectivity over other CDKs and potent cellular effects. Based on these characterizations, we propose that compound 22 holds great promise as a potential lead candidate for drug development.

The Clinicopathological Significance of the Cyclin D1/E1-Cyclin-Dependent Kinase (CDK2/4/6)-Retinoblastoma (RB1/pRB1) Pathway in Epithelial Ovarian Cancers.

Cyclin-dependent kinases (CDK2, CDK4, CDK6), cyclin D1, cyclin E1 and phosphorylated retinoblastoma (pRB1) are key regulators of the G1/S cell cycle checkpoint and may influence platinum response in ovarian cancers. CDK2/4/6 inhibitors are emerging targets in ovarian cancer therapeutics. In the current study, we evaluated the prognostic and predictive significance of the CDK2/4/6-cyclin D1/E1-pRB1 axis in clinical ovarian cancers (OC). The CDK2/4/6, cyclin D1/E1 and RB1/pRB1 protein expression were investigated in 300 ovarian cancers and correlated with clinicopathological parameters and patient outcomes. CDK2/4/6, cyclin D1/E1 and RB1 mRNA expression were evaluated in the publicly available ovarian TCGA dataset. We observed nuclear and cytoplasmic staining for CDK2/4/6, cyclins D1/E1 and RB1/pRB1 in OCs with varying percentages. Increased nuclear CDK2 and nuclear cyclin E1 expression was linked with poor progression-free survival (PFS) and a shorter overall survival (OS). Nuclear CDK6 was associated with poor OS. The cytoplasmic expression of CDK4, cyclin D1 and cyclin E1 also has predictive and/or prognostic significance in OCs. In the multivariate analysis, nuclear cyclin E1 was an independent predictor of poor PFS. Tumours with high nuclear cyclin E1/high nuclear CDK2 have a worse PFS and OS. Detailed bioinformatics in the TCGA cohort showed a positive correlation between cyclin E1 and CDK2. We also showed that cyclin-E1-overexpressing tumours are enriched for genes involved in insulin signalling and release. Our data not only identified the prognostic/predictive significance of these key cell cycle regulators but also demonstrate the importance of sub-cellular localisation. CDK2 targeting in cyclin-E1-amplified OCs could be a rational approach.

Bruceantinol works as a CDK2/4/6 inhibitor to inhibit the growth of breast cancer cells.

Bruceantinol (BOL), isolated from the dried fruit of the Brucea javanica (L.) Merr., exhibits cytotoxic effects on breast cancer cells. However, the underlying mechanism remains to be fully addressed. In this paper, the MCF-7 and MDA-MB-231 human breast cancer cell lines were used as experimental models to uncover how BOL inhibits breast cancer cell growth. The effects of BOL on cell growth, proliferation, the cell cycle, and apoptosis were investigated using the MTT assays, EdU incorporation assays, and flow cytometry, respectively. Bioinformatics techniques were applied to predict the key targets of BOL in breast cancer. Subsequent validation of these targets and the anti-breast cancer mechanism of BOL was conducted through Western blotting, RT-PCR, siRNA transfection, and molecular docking analysis. The results demonstrated that BOL dose- and time-dependently reduced the growth of both cell lines, impeded cell proliferation, disrupted the cell cycle, and induced necrosis in MCF-7 cells and apoptosis in MDA-MB-231 cells. Furthermore, CDK2/4/6 were identified as BOL targets, and their knockdown reduced cell sensitivity to BOL. BOL was found to potentially bind with CDK2/4/6 to facilitate protein degradation through the proteasome pathway. Additionally, BOL activated ERK in MDA-MB-231 cells, and this activation was required for BOL's functions in these cells. Collectively, BOL may act as an inhibitor of CDK2/4/6 to exert anti-breast cancer effects. Its effects on cell growth and CDK2/4/6 expression may also depend on ERK activation in HRs-HER2- breast cancer cells. These results suggest the potential of using BOL for treating breast cancer.

Effects of silencing NLRP3 gene on proliferation of psoriasis-like HaCaT cells and expressions of cytokines.

We aimed to explore the effects of silencing NOD-like receptor protein 3 (NLRP3) on proliferation of psoriasis-like HaCaT cells and expressions of cytokines. HaCaT cells were treated with human keratinocyte growth factor (KGF) and were divided into KGF group, negative control group, NLRP3-RNAi group and control group. Cells proliferation was detected by CCK8, cell clone formation rate was detected by clone formation assay, distribution of cells cycle was detected by flow cytometry, expressions of cyclin B1 (Cyclin B1), cyclin-dependent kinase 2 (CDK2), Ki67 and proliferating cell nuclear antigen (PCNA) proteins were detected by Western blot, and levels of interleukin (IL)-17, IL-23, IL-6 and tumor necrosis factor α (TNF-α) were detected by enzyme-linked immunosorbent assay. Compared with control group, expressions of NLRP3 mRNA and protein, proliferation rate and clonal formation rate were increased in KGF group, percentage of cells in G0/G1 phase was decreased, percentage of cells in S phase was increased, expressions of Cyclin B1, CDK2, Ki67 and PCNA proteins were increased, and levels of IL-17, IL-23, IL-6 and TNF-α were increased. Compared with negative control group, expressions of NLRP3 mRNA and protein, proliferation rate and clonal formation rate were decreased in NLRP3-RNAi group, percentage of cells in G0/G1 phase was increased, percentage of cells in S phase was decreased, expressions of Cyclin B1, CDK2, Ki67 and PCNA proteins were decreased, and levels of IL-17, IL-23, IL-6 and TNF-α were decreased. Silencing NLRP3 gene can inhibit the proliferation of psoriasis-like HaCaT cells, arrest cell cycle, inhibit the expressions of cell proliferation-related proteins and reduce levels of pro-inflammatory factors.

Hsa_circ_0005320 affects cell proliferation and the cell cycle via the IGF2BP3/CDK2 axis in bladder cancer.

BACKGROUND: Circular RNAs (circRNAs), which are covalently closed non-coding RNAs, are frequently dysregulated in cancer. However, their precise role in bladder cancer (BCa) remains largely unknown. METHODS: Expression of hsa_circ_0005320 in tissues and cell lines was detected using quantitative real-time PCR. Proliferation and colony forming capacity of BCa cells were assessed using Cell Counting Kit-8, ethynyl-labeled deoxyuridine, and colony formation assays. The cell cycle was analyzed using flow cytometry. Protein expression of insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3) and cyclin dependent kinase 2 (CDK2) was examined using western blots. The binding of RNA and protein was validated using RNA immunoprecipitation. Additionally, xenograft tumor models were established to validate the function of hsa_circ_0005320 in vivo. RESULTS: We screened hsa_circ_0005320 from previous high-throughput sequencing and found that it was highly expressed in BCa tissues and associated with tumor differentiation and depth of invasion in BCa patients. Through functional experiments, we demonstrated that hsa_circ_0005320 promoted cell proliferation and regulated the cell cycle. Mechanistically, hsa_circ_0005320 interacted with and upregulated the expression of IGF2BP3, which binds to and enhances the stability of CDK2 mRNA. Furthermore, knockdown of hsa_circ_0005320 resulted in a reduction in tumor burden in vivo. CONCLUSIONS: Collectively, these findings highlight the pro-oncogenic role of hsa_circ_0005320 in BCa through the IGF2BP3/CDK2 axis, providing valuable insights into the mechanism of circRNAs in tumor progression.

Whole-transcriptome profiling reveals potential biomarkers for the reversal of thymic epithelial cell senescence by umbilical cord mesenchymal stem cells.

BACKGROUND: Reduced numbers and dysfunction of thymic epithelial cells (TECs) are important factors of thymic degeneration. Previous studies have found that umbilical cord mesenchymal stem cells (UCMSCs) reverse the structure and function of the senescent thymus in vivo. However, the transcriptomic regulation mechanism is unclear. METHODS: TECs were cultured with H2O2 for 72 hours to induce senescence. UCMSCs were cocultured with senescent TECs for 48 hours to detect SA-ß-gal, P16 and Ki67. The cocultured TECs were collected for lncRNA, mRNA and miRNA sequencing to establish a competitive endogenous regulatory network (ceRNA). And RT-qPCR, immunofluorescence staining, and western blot were used to identified key genes. RESULTS: Our results showed that H2O2 induced TEC aging and that UCMSCs reversed these changes. Compared with those in aged TECs, 2260 DE mRNAs, 1033 DE lncRNAs and 67 DE miRNAs were differentially expressed, and these changes were reversed by coculturing the cells with UCMSCs. Differential mRNA enrichment analysis of ceRNA regulation revealed that the PI3K-AKT pathway was a significant signaling pathway. UCMSC coculture upregulated VEGFA, which is the upstream factor of the PI3K-AKT signaling pathway, and the expression of the key proteins PI3K and AKT. Thus, the expression of the cell cycle suppressor P27, which is downstream of the PI3K-AKT signaling pathway, was downregulated, while the expression of the cell cycle regulators CDK2 and CCNE was upregulated. CONCLUSION: UCMSC coculture upregulated the expression of VEGFA, activated the PI3K-AKT signaling pathway, increased the expression of CDK2 and CCNE, decreased the expression of P27, and promoted the proliferation of TECs.

Phosphorylation of Tau Protein by CDK2/cyclin A and GSK3ß Recombinant Kinases: Analysis of Phosphorylation Patterns by Nuclear Magnetic Resonance Spectroscopy.

Posttranslational modifications (PTMs) of proteins can be investigated by Nuclear Magnetic Resonance (NMR) spectroscopy as a powerful analytical tool to define modification sites, their relative stoichiometry, and crosstalk between modifications. As a Structural Biology method, NMR provides important additional information on changes in protein conformation and dynamics upon modification as well as a mapping of binding sites upon biomolecular interactions. Indeed, PTMs not only mediate functional modulation in protein-protein interactions, but can also induce diverse structural responses with different biological outcomes. Here we present protocols that have been developed for the production and phosphorylation of the neuronal tau protein. Under its aggregated form, tau is a hallmark of Alzheimer's disease and other neurodegenerative diseases named tauopathies involving tau dysfunction and/or mutations. As a common feature shared by various tauopathies, tau aggregates are found into a form displaying an increased, abnormal phosphorylation, also referred to hyperphosphorylation. We have used NMR to investigate the phosphorylation patterns of tau induced by several kinases or cell extracts, how phosphorylation affects the local and overall conformation of tau, its interactions with partners (proteins, DNA, small-molecules, etc.) including tubulin and microtubules, and its capacity to form insoluble fibrillar aggregates. We present here detailed protocols for in vitro phosphorylation of tau by the recombinant kinases CDK2/cyclin A and GSK3ß, the production of the recombinant kinases thereof, as well as the analytical characterization of phosphorylated tau by NMR spectroscopy.

A Highly Anticipated Selective Therapeutic Agent against CDK2: INX-315.

SUMMARY: In this issue, Dietrich, Trub, and colleagues describe and characterize a novel selective CDK2 inhibitor: INX-315. This agent shows promise in CCNE1-amplified cancers and in CDK4/6 inhibitor-resistant breast cancers. See related article by Dietrich et al., p. 446 (8).