Cell Cycle最新文献

Transposable elements (TEs) are mobile DNA sequences capable of self-replication (especially retrotransposons) within the genome, which may lead to various forms of DNA damage. The introduction of this review encompasses the diverse classes and subclasses of TEs, particularly emphasizing the most active TEs present in the human genome. An analysis of the retrotransposition process of TEs is presented, illustrating how this mechanism can result in DNA damage and gene rearrangements. Furthermore, the review meticulously examines the implications of TE insertions on gene expression and genomic organization, which may contribute to the development of various diseases, including cancer. The relationship between TE activation and the aging process is also explored, with an emphasis on that epigenetic modifications associated with aging can lead to the derepression of TEs, thereby promoting genomic instability and inflammation. These factors may play a significant role in the pathogenesis of age-related diseases, such as cancer, cardiovascular disorders, and neurodegenerative conditions. Finally, the review considers potential therapeutic approaches aimed at targeting TE activity to alleviate the impacts of aging and associated diseases.

Growth hormone (GH) is given to GH-deficient but also to non-GH-deprived children to promote growth. Since standard treatment requires tedious daily injections, long-release formulations are sought. However, non-GH-deficient conditions require higher dosing, which could entail cancer risk. To evaluate the hepatic pro-oncogenic potential of continuous GH under non-GH-deprived conditions, mice were implanted with osmotic minipumps for 5 wk during the growth period. GH secretion and hepatic actions are sexually dimorphic, thus both sexes were studied. Body growth was assessed since birth, whereas the impact on liver, a major GH target organ, was evaluated upon treatment ending, at 8 wk of age. Used dose, 6 µg/g BW, effective when given intermittently, failed to promote growth when infused continuously. Hepatocytes presented higher PCNA-stain, indicative of proliferation, in GH-treated males. STAT5 phosphorylation, related to somatic growth and metabolic GH actions, was not affected by continuous GH levels, whereas STAT3, associated with cellular growth and proliferation, was activated in females. In males, continuous GH treatment induced a female-like hepatic expression of IGF1 and cyclin D1, as well as that of MUPs and EGFR, showing that they are regulated by GH but, moreover, by the GH continuous concentration pattern. GHR and SOCS2 mRNA levels were upregulated by continuous GH in both sexes, whereas c-myc and CIS mRNA were mainly induced in female liver. These results indicate that although continuous GH administration in the used dose is not sufficient to promote growth in non-GH-deprived conditions, it may foster hepatic molecular signatures associated with potentially prooncogenic signaling in mice.

Glioblastoma multiforme (GBM) is the most common form of malignant brain cancer and is generally approached with palliative intent. Preclinical studies suggest that short-term fasting may be an effective tool for enhancing existing cancer therapies by disrupting the glucose-dependent, oncogenic phenotype of many cancers. In this study, we investigated whether a fasting-mimicking environment (FME) enhances the efficacy of an emerging proapoptotic drug, procaspase-activating compound 1 (PAC-1), in 2D and 3D GBM cell models. Ad libitum food consumption (Fed) and FME conditions were simulated in vitro by modifying glucose, ketone and serum concentrations. The FME conditions enhanced PAC-1 in U87-MG, T98G and 9L-GS monolayer experiments by significantly reducing the PAC-1 50% inhibitory concentration (IC₅₀), delaying cell growth and increasing apoptosis. Similarly, in the 3D spheroid models, the minimum concentration of PAC-1 required to reduce U87-MG and 9L-GS spheroid area was lower in the FME conditions than the Fed conditions. Additionally, we discovered that serum restriction was primarily responsible for the FME-induced PAC-1 enhancement. These finding are the first to demonstrate that fasting-mimicking conditions sensitize 2D and 3D glioma cell models to PAC-1, supporting the use of short-term fasting as a low-cost and widely accessible strategy for enhancing cancer therapies.

Pancreatic adenocarcinoma (PAAD) is a highly aggressive malignant tumor of the gastrointestinal tract. Goosecoid (GSC), translated from a homeobox gene, is a protein participating in metastasis of assorted tumors. This study explores the role of GSC implicated in tumor metastasis, in PAAD progression. GSC expression in PAAD tissues and cells were tested by quantitative polymerase chain reaction (PCR) and western blot. GSC mRNA and protein expressions were elevated in PAAD tissues and cells. The impacts of GSC depletion or upregulation on PAAD cell proliferation, migration, invasion, cell cycle, and apoptosis were determined by colony formation assay, transwell assay, and flow cytometry. E-cadherin and N-cadherin expressions were tested through immunofluorescence to evaluate the epithelial-mesenchymal transition (EMT) process. The results showed that GSC depletion notably restrained cell proliferative and migratory capabilities and cell cycle, declined MMP2 and MMP9 activity, suppressed EMT process, and enhanced cell apoptosis. Nevertheless, GSC overexpression showed the opposite functions. Stem cell markers CD44 and CD133 were suppressed by GSC depletion and enhanced by GSC overexpression. Additionally, a sphere formation assay was implemented to test cell stemness. The levels of key proteins on TGF-β signaling were tested by western blot. GSC could activate TGF-β signaling in cells by promoting SMAD2/3 phosphorylation. The pathway inhibitor SIS3 notably counteracted the functions on cell malignant phenotypes induced by GSC overexpression. Moreover, xenograft tumor-bearing mouse models were established using male BALB/c nude mice to explore the effects of GSC knockdown on tumor growth and metastasis in vivo, and we found that GSC knockdown inhibited PAAD tumor growth and metastasis in xenograft models. GSC is expressed at a high level in PAAD and can facilitate PAAD metastasis by enhancing EMT and stemness via regulating TGF-β/SMAD2/3 signaling.

The ability of tumor cells to migrate and invade adjacent tissue is a key property underlying the metastatic process. To ensure greater deformability and to facilitate movement, migratory cells undergo multiple changes in biophysical parameters, including those of stiffness and membrane viscosity. However, reports on correlations between cell motility and stiffness, or between cell motility and membrane microviscosity are rather limited and conflicting. Here, using atomic force microscopy (AFM) and fluorescence lifetime imaging (FLIM), we have investigated alterations in the mechanical properties of cancer cells and in the microviscosity of their plasma membranes that are associated with the migration process. It was found that upon activation of migration either through a "wound healing" test or by inducing epithelial-mesenchymal transition, human colorectal cancer cells undergo profound biomechanical remodeling characterized by simultaneous decreases in cell stiffness and in plasma membrane microviscosity. Our findings, therefore, support the results of previous studies that have shown cell softening and membrane fluidization to be critical adaptive responses enabling cell movement and that these can be regarded as potential biomarkers of tumor cell motility, offering scope for identifying new therapeutic targets.

The tumor suppressor p53 protects genomic integrity in part by regulating transposable elements (TEs). Studies of p53-TE interactions rely on synthetic DNA and reporter assays, estimating expression only at the family or subfamily level and lacking locus-specific resolution. To address this limitation, we developed a computational pipeline for ChIP-seq and RNA-seq analysis that employs advanced algorithms to accurately assign short reads mapping to multiple genomic locations. This approach enables precise quantification of TE transcripts at the locus level. By integrating p53 ChIP peaks with differentially expressed TE transcripts, we performed a global analysis of TE expression upon p53 binding. Applying this framework to lung fibroblast IMR90 and colon cancer HCT116 cells treated with p53 activators, we observed a striking pattern: TEs were predominantly activated in normal IMR90 cells but repressed in HCT116 cancer cells. Further analysis of 24 transcriptomes and 10 cistromes confirmed this trend as a distinguishing hallmark between normal and cancer cells. At the family level, normal cells showed broad TE upregulation, whereas cancer cells exhibited selective repression of Alu and LINE elements. These findings provide the first comprehensive, locus-specific view of TE expression associated with p53 binding, implicating a potential role of chromatin context in TE regulation.

TCAB1 (telomerase Cajal body protein 1), encoded by the WRAP53 gene on chromosome 17p13.1, is a molecular scaffold critical for protein-nucleic acid interactions. In normal cells, TCAB1 plays a pivotal role in localizing telomerase to Cajal bodies, thereby ensuring proper telomere maintenance and genomic stability. In cancer cells, however, TCAB1 is frequently overexpressed, which supports unchecked proliferation and therapy resistance. Conversely, knockdown of TCAB1 triggers multiple tumor-suppressive mechanisms, including G1 cell cycle arrest - mediated by impaired p21 ubiquitination and subsequent Cyclin E/CDK2 inactivation - as well as telomere shortening and genomic instability due to mitochondrial dysfunction and defective DNA repair. Notably, the induction of cellular senescence emerges as a key anticancer mechanism upon TCAB1 depletion, particularly in early-stage tumors retaining wild-type p53. This review delineates the dual roles of TCAB1, highlighting its function as a context-dependent oncoprotein and the therapeutic potential of targeting it to induce senescence.

Background: Colorectal cancer (CRC) represents a significant global health burden, requiring a deeper understanding of the molecular mechanisms that drive its progression. Circular RNAs (circRNAs) have appeared as crucial regulators in cancer, with circ_0050102 as a potential functional molecule in CRC. The present study aimed to determine the diagnostic and functional implications of circ_0050102 in CRC pathogenesis.

Methods: The GSE172229, GSE205094, and GSE134834 datasets were used for the comprehensive analyses of circRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) in CRC tumor samples. Functional experiments, including fluorescence in situ hybridization, knockdown assays, flow cytometric analysis, and luciferase reporter assay, were conducted to investigate the effect of circ_0050102 on CRC cell behavior. CircRNA - miRNA - mRNA interaction analysis provided information about the regulatory network that involved circ_0050102, miR-3622a-3p, and baculoviral IAP repeat-containing 5 (BIRC5). Furthermore, the functional impact of circ_0050102 on CRC tumor growth was investigated using in vivo xenograft models.

Results: Our analysis determined circ_0050102 as a significantly differentially expressed circRNA in CRC, with a high area under the receiver operating characteristic curve value, indicating its diagnostic potential. Functional experiments revealed that circ_0050102 is predominantly localized in the cytoplasm of CRC tumor cells, and its knockdown significantly attenuates various CRC cell behavior aspects, including viability, invasion, and migration (p < 0.05). The interaction analysis revealed a potential regulatory axis that involves circ_0050102, miR-3622a-3p, and BIRC5. In vivo experiments demonstrated that circ_0050102 knockdown significantly attenuated CRC tumor development.

Conclusion: Our results revealed that circ_0050102 promotes CRC progression through miR-3622a-3p and BIRC5. The circ_0050102-mediated regulatory network provides valuable information about the intricate mechanisms contributing to CRC pathogenesis.