Cyclin Y binds and activates CDK4 to promote the G1/S phase transition in hepatocellular carcinoma cells via Rb signaling

TK1 expression influences pathogenicity by cell cycle progression, cellular migration, and cellular survival in HCC 1806 breast cancer cells

Breast cancer is the most common cancer diagnosis worldwide accounting for 1 out of every 8 cancer diagnoses. The elevated expression of Thymidine Kinase 1 (TK1) is associated with more aggressive tumor grades, including breast cancer. Recent studies indicate that TK1 may be involved in cancer pathogenesis; however, its direct involvement in breast cancer has not been identified. Here, we evaluate potential pathogenic effects of elevated TK1 expression by comparing HCC 1806 to HCC 1806 TK1-knockdown cancer cells (L133). Transcriptomic profiles of HCC 1806 and L133 cells showed cell cycle progression, apoptosis, and invasion as potential pathogenic pathways affected by TK1 expression. Subsequent in-vitro studies confirmed differences between HCC 1806 and L133 cells in cell cycle phase progression, cell survival, and cell migration. Expression comparison of several factors involved in these pathogenic pathways between HCC 1806 and L133 cells identified p21 and AKT3 transcripts were significantly affected by TK1 expression. Creation of a protein-protein interaction map of TK1 and the pathogenic factors we evaluated predict that the majority of factors evaluated either directly or indirectly interact with TK1. Our findings argue that TK1 elevation directly increases HCC 1806 cell pathogenicity and is likely occurring by p21- and AKT3-mediated mechanisms to promote cell cycle arrest, cellular migration, and cellular survival.

Mitochondrial creatine kinase 1 regulates the cell cycle in non-small cell lung cancer via activation of cyclin-dependent kinase 4

BACKGROUND

Non-small cell lung cancer (NSCLC) is the main type of the most common malignant tumor in the world. Previous studies have shown that the expression level of mitochondrial creatine kinase 1 (CKMT1) is abnormal in NSCLC, but the mechanism of its effect remains unclear. Therefore, in this study, we intend to clarify the potential mechanism of CKMT1 in NSCLC and provide the theoretical basis for the clinical application of CKMT1.

METHODS

The function of CKMT1 in NSCLC was identified by analyzing the GEO dataset and evaluating using in vitro and in vivo models. Protein mass spectrometry was used to find proteins interacting with CKMT1, and Co-immunoprecipitation (Co-IP) and GST-pull down experiments were used to verify the interaction between proteins. The immunofluorescence (IF) assay was used to explore the functional position of CKMT1 in cells. The effect of CKMT1 expression level on the efficacy of paclitaxel (TAX) in the treatment of NSCLC was analyzed by a combined TAX experiment in vivo and in vitro.

RESULTS

CKMT1 expression was increased in NSCLC and CKMT1 promoted the proliferation of NSCLC cells in vitro and in vivo. CKMT1 knockdown resulted in a significantly increased G0/G1 fraction and decreased S phase cell fraction, indicating G1 phase arrest. Mechanically, the cyclin-dependent kinase 4 (CDK4) was identified to interact with CKMT1, and the crucial binding areas were focused on the DH domain of CKMT1 and the N- and C-terminal of CDK4. A fraction of the CDK4 proteins colocalize and interact with the CKMT1 at mitochondria, the level of phosphorylated CDK4 was regulated by CKMT1. Hence, the decrease in CKMT1 expression level could increase the antitumor effect of G2/M cell cycle antagonist-TAX in NSCLC in vitro and in vivo.

CONCLUSIONS

CKMT1 could interact with CDK4 in mitochondria and regulate the phosphorylated level of CDK4, thus contributing to the proliferation and cell cycle transition of NSCLC cells. And CKMT1 could be a potential target to improve the sensitivity of chemotherapy based on TAX.

The role of cyclin Y in normal and pathological cells

The family protein of cyclins, as well as cyclin-dependent kinases (CDKs) cooperating with them, are broadly researched, as a matter of their dysfunction may lead to tumor transformation. Cyclins are defined as key regulators that have a controlling function of the mammalian nuclear cell divides. Cyclin Y (CCNY) is a recently characterized member of the cyclin family and was first identified from the human testis cDNA library. It is an actin-binding protein acting through decreased actin dynamics at a steady state and during glycine-induced long-term potentiation (LTP) and involves the inhibition of cofilin activation. What is more, CCNY is a positive regulatory subunit of the CDK14/PFTK1 complexes affected by the activation of the Wnt signaling pathway in the G2/M phase by recruiting CDK14/PFTK1 to the plasma membrane and promoting phosphorylation of LRP6. The expression of CCNY has been significantly mentioned within the cell migration and invasion activity both in vivo and in vitro. The aim of this review is evaluation of the expression of CCNY in the physiology processes and compare the expression of this protein in cancer cells, taking into account the impact of the level of expression on tumor progression.

Epstein-Barr virus miR-BART2-5p and miR-BART11-5p regulate cell proliferation, apoptosis, and migration by targeting RB and p21 in gastric carcinoma

Epstein-Barr virus (EBV) was the first tumor virus discovered in humans and can cause various types of tumors. Molecular classification suggests that EBV-associated gastric cancer (EBVaGC) is a unique subtype of gastric cancer.EBV was also the first virus found to encode its own microRNAs. However, the functions of many miRNAs remain unknown. This study investigated the roles and targets of miR-BART2-5p (BART2-5p) and miR-BART11-5p (BART11-5p) in EBVaGC. The expression of RB and p21 in EBVaGC and EBV negative GC (EBVnGC) cells was evaluated by western blotting. Expression of BART2-5p and BART11-5p in EBVaGC cells was evaluated by droplet digital PCR. The effects of BART2-5p or BART11-5p and their potential mechanisms were further investigated using cell counting kit-8, colony formation assay, flow cytometry analysis, and transwell assay. BART2-5p and BART11-5p were abundantly expressed and RB and p21 were downregulated in EBVaGC cells. BART2-5p regulates RB and p21 expression by directly targeting them. BART11-5p regulates RB expression by directly targeting RB. Both BART2-5p and BART11-5p promoted proliferation and migration of gastric cancer cells, while inhibiting apoptosis and promoting S-phase arrest of the cell cycle. Thus, BART2-5p and BART11-5p play important roles in promoting proliferation and migration, and inhibiting apoptosis in EBVaGC by targeting RB and p21, thus providing new potential therapeutic targets for EBVaGC.

RNA-seq and ATAC-seq analyses of multilineage differentiating stress enduring cells: Comparison with dermal fibroblasts

The aim of this study is to characterize the molecular properties of multilineage differentiating stress-enduring (Muse) cells compared with dermal fibroblasts (FBs) and to characterize differences in their transcriptomes and open chromatin regions that are involved in cellular plasticity. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) analyses was then performed on FBs and Muse cells. Subsequently, cell type-selective gene regulatory regions were identified by coalition analysis. Expression patterns of transcription factors (TFs) and signaling pathways intermediates were verified using quantitative real-time polymerase chain reaction and Western blot analyses. RNA-seq identified 2355 significantly differentially expressed genes (DEGs) that regulate the transcriptome, including 1222 upregulated and 1133 downregulated DEGs. The general panorama of RNA-seq and ATAC-seq analyses confirmed the differences in TFs and open chromatin regions between FBs and Muse cells. ATAC-seq analysis showed that Muse cells had more reproducible and meaningful peaks than FBs, and the peak signals were concentrated near promoter-transcription start site areas. In genomic regions that can be preferentially accessed in FBs and Muse cells, more than 200 TFs had binding motif sequences. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and coalition analyses identified differences in factors involved in the cell cycle and the protein kinase B (AKT) signaling pathway of FBs and Muse cells. The results of RNA-seq and ATAC-seq analyses clarified the genetic basis of the different biological properties of Muse cells and FBs. These results suggest that the cell cycle transition and the AKT signaling pathway may affect the morphology and biological characteristics of Muse cells.

Post-translational modifications on the retinoblastoma protein

The retinoblastoma protein (pRb) functions as a cell cycle regulator controlling G1 to S phase transition and plays critical roles in tumour suppression. It is frequently inactivated in various tumours. The functions of pRb are tightly regulated, where post-translational modifications (PTMs) play crucial roles, including phosphorylation, ubiquitination, SUMOylation, acetylation and methylation. Most PTMs on pRb are reversible and can be detected in non-cancerous cells, playing an important role in cell cycle regulation, cell survival and differentiation. Conversely, altered PTMs on pRb can give rise to anomalies in cell proliferation and tumourigenesis. In this review, we first summarize recent findings pertinent to how individual PTMs impinge on pRb functions. As many of these PTMs on pRb were published as individual articles, we also provide insights on the coordination, either collaborations and/or competitions, of the same or different types of PTMs on pRb. Having a better understanding of how pRb is post-translationally modulated should pave the way for developing novel and specific therapeutic strategies to treat various human diseases.

Cyclin-Dependent Kinase 4 is expected to be a therapeutic target for hepatocellular carcinoma metastasis using integrated bioinformatic analysis

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. HCC cells possess biological characteristics of high invasion and metastasis. In this respect, to prevent cancer cell invasion and metastasis and early active intervention, we herein screened through the TCGA database for further prognostic analysis including overall survival and disease-free survival . The Kaplan-Meier curve suggested that Cyclin-Dependent Kinase 4 (CDK4) might be an independent prognostic factor for HCC. Moreover, we performed mRNA expression analysis to measure CDK4 levels in normal liver tissues and HCC tissues, and immunohistochemistry analysis to detect protein level of CDK4 in Non-tumor tissue and HCC tissues . Our findings indicated that the expression of CDK4 was significantly higher in tumor tissues compared with Non-tumor tissue in HCC, which increased from HCC stage 1 to 3. Furthermore, the results of transwell-assay indicated that knocking down CDK4 significantly suppresses the invasion and migration of HCC cells, and the results of bioinformatics analysis revealed that genes closely associated with CDK4 are potentially worthy of further investigation. Additionally, the results of Western Blot indicated CDK4 regulates epithelial mesenchymal transition in HCC,and CDK4 appears to regulate EMT and HCC progression via the Wnt/β-catenin pathway. Collectively, this study found the key target gene through bioinformatic analysis and further functional validation through cell experiments. In particular, CDK4 is anticipated to become a crucial hub gene to snipe the metastasis of cancer cells in HCC.Abbreviations: Hepatocellular carcinoma (HCC);Cyclin-Dependent Kinase 4(CDK4);Genomic Data Commons (GDC); genes; EC, Endometrial cancer; GEO, gene expression omnibus; GO, Gene Ontology; GSEA, Gene set enrichment analysis; KEGG, Database; TCGA, The Cancer Genome Atlas; TSGs, tumor suppressor genes;epithelial mesenchymal transition (EMT).

Suppression of Heterogeneous Nuclear Ribonucleoprotein C Inhibit Hepatocellular Carcinoma Proliferation, Migration, and Invasion via Ras/MAPK Signaling Pathway

Hepatocellular carcinoma (HCC), the most common malignant tumor, has high fatality and recurrence rates. Accumulating evidence shows that heterogeneous nuclear ribonucleoprotein C (HNRNPC), which is mainly involved in RNA splicing, export, and translation, promotes progression and metastasis of multiple tumor types; however, the effects of HNRNPC in HCC are unknown. In the present study, high levels of HNRNPC were detected in tumor tissues compared with para-tumor tissues by immunohistochemical and western blot assays. Furthermore, Cox proportional hazards regression models, the Kaplan–Meier method, and clinicopathologic features analysis showed that HNRNPC was not only an independent prognostic factor for both overall and disease-free survival in HCC but also a predictor of large tumor size and advanced tumor stage. Functional experiments revealed that silencing of HNRNPC not only led to arrest of more HCC cells at G0/G1 phase to inhibit their proliferation, but also suppressed EMT process to block their invasion, and migration in vitro; this was related to the Ras/MAPK signaling pathway. In addition, blocking of HCC cell proliferation regulated by HNRNPC silencing was observed in vivo. Finally, rescue tests showed that after recovery of Ras/MAPK signaling pathway activity by treatment with Ras agonists, the proliferation, migration, and invasion suppression of Huh-7 and Hep 3B cell lines caused by HNRNPC knockdown was partially reversed. Taken together, these results indicate that HNRNPC knockdown inhibits HCC cell proliferation, migration and invasion, in part via the Ras/MAPK signaling pathway. Thus, HNRNPC may have an important role in the progression of HCC and represents a promising biomarker for evaluation of prognosis and a potential therapeutic target in HCC patients.