The second half of mitosis and its implications in cancer biology

Integrating machine learning models with multi-omics analysis to decipher the prognostic significance of mitotic catastrophe heterogeneity in bladder cancer

BACKGROUND

Mitotic catastrophe is well-known as a major pathway of endogenous tumor death, but the prognostic significance of its heterogeneity regarding bladder cancer (BLCA) remains unclear.

METHODS

Our study focused on digging deeper into the TCGA and GEO databases. Through differential expression analysis as well as Weighted Gene Co-expression Network Analysis (WGCNA), we identified dysregulated mitotic catastrophe-associated genes, followed by univariate cox regression as well as ten machine learning algorithms to construct robust prognostic models. Based on prognostic stratification, we revealed intergroup differences by enrichment analysis, immune infiltration assessment, and genomic variant analysis. Subsequently by multivariate cox regression as well as survshap(t) model we screened core prognostic gene and identified it by Mendelian randomization. Integration of qRT-PCR, immunohistochemistry, and single-cell analysis explored the core gene expression landscape. In addition, we explored the ceRNA axis containing upstream non-coding RNAs after detailed analysis of pathway activation, immunoregulation, and methylation functions of the core genes. Finally, we performed drug screening and molecular docking experiments based on the core gene in the DSigDB database.

RESULTS

Our efforts culminated in the establishment of an accurate prognostic model containing 16 genes based on Coxboost as well as the Random Survival Forest (RSF) algorithm. Detailed analysis from multiple perspectives revealed a strong link between model scores and many key indicators: pathway activation, immune infiltration landscape, genomic variant landscape, and personalized treatment. Subsequently ANLN was identified as the core of the model, and prognostic analysis revealed that it portends a poor prognosis, further corroborated by Mendelian randomization analysis. Interestingly, ANLN expression was significantly upregulated in cancer cells and specifically clustered in epithelial cells and provided multiple pathways to mediate cell division. In addition, ANLN regulated immune infiltration patterns and was also inseparable from overall methylation levels. Further analysis revealed potential regulation of the MIR4435-2HG, hsa-miR-15a-5p, ANLN axis and highlighted a range of potential therapeutic agents including Phytoestrogens.

CONCLUSION

The model we developed was a powerful predictive tool for BLCA prognosis and revealed the impact of mitotic catastrophe heterogeneity on BLCA in multiple dimensions, which then guided clinical decision-making. Furthermore, we highlighted the potential of ANLN as a BLCA target.

Quantitative Live-Cell Imaging to Study Chromatin Segregation and Nuclear Reformation

Live-cell imaging is a powerful tool for the investigation of different steps of the life and fate of single cells and cell populations. In this chapter, we describe how to perform live-cell imaging in tissue culture cells and the subsequent image analysis to precisely characterize the cytological events occurring during mitotic exit and nuclear reformation.

Sculpting nuclear envelope identity from the endoplasmic reticulum during the cell cycle

The nuclear envelope (NE) regulates nuclear functions, including transcription, nucleocytoplasmic transport, and protein quality control. While the outer membrane of the NE is directly continuous with the endoplasmic reticulum (ER), the NE has an overall distinct protein composition from the ER, which is crucial for its functions. During open mitosis in higher eukaryotes, the NE disassembles during mitotic entry and then reforms as a functional territory at the end of mitosis to reestablish nucleocytoplasmic compartmentalization. In this review, we examine the known mechanisms by which the functional NE reconstitutes from the mitotic ER in the continuous ER-NE endomembrane system during open mitosis. Furthermore, based on recent findings indicating that the NE possesses unique lipid metabolism and quality control mechanisms distinct from those of the ER, we explore the maintenance of NE identity and homeostasis during interphase. We also highlight the potential significance of membrane junctions between the ER and NE.

Novel 2,7-Naphthyridine Compounds as MASTL Inhibitors for Treating Cancer

Provided herein are novel 2,7-naphthyridine compounds as MASTL inhibitors, pharmaceutical compositions, use of such compounds in treating cancer, and processes for preparing such compounds.

The two sides of chromosomal instability: drivers and brakes in cancer

Chromosomal instability (CIN) is a hallmark of cancer and is associated with tumor cell malignancy. CIN triggers a chain reaction in cells leading to chromosomal abnormalities, including deviations from the normal chromosome number or structural changes in chromosomes. CIN arises from errors in DNA replication and chromosome segregation during cell division, leading to the formation of cells with abnormal number and/or structure of chromosomes. Errors in DNA replication result from abnormal replication licensing as well as replication stress, such as double-strand breaks and stalled replication forks; meanwhile, errors in chromosome segregation stem from defects in chromosome segregation machinery, including centrosome amplification, erroneous microtubule-kinetochore attachments, spindle assembly checkpoint, or defective sister chromatids cohesion. In normal cells, CIN is deleterious and is associated with DNA damage, proteotoxic stress, metabolic alteration, cell cycle arrest, and senescence. Paradoxically, despite these negative consequences, CIN is one of the hallmarks of cancer found in over 90% of solid tumors and in blood cancers. Furthermore, CIN could endow tumors with enhanced adaptation capabilities due to increased intratumor heterogeneity, thereby facilitating adaptive resistance to therapies; however, excessive CIN could induce tumor cells death, leading to the "just-right" model for CIN in tumors. Elucidating the complex nature of CIN is crucial for understanding the dynamics of tumorigenesis and for developing effective anti-tumor treatments. This review provides an overview of causes and consequences of CIN, as well as the paradox of CIN, a phenomenon that continues to perplex researchers. Finally, this review explores the potential of CIN-based anti-tumor therapy.

Methods for Inferring Cell Cycle Parameters Using Thymidine Analogues

Tritiated thymidine autoradiography, 5-bromo-2'-deoxyuridine (BrdU) 5-chloro-2'-deoxyuridine (CldU), 5-iodo-2'-deoxyuridine (IdU), and 5-ethynyl-2'-deoxyiridine (EdU) labeling have been used for identifying the fraction of cells undergoing the S-phase of the cell cycle and to follow the fate of these cells during the embryonic, perinatal, and adult life in several species of vertebrate. In this current review, I will discuss the dosage and times of exposition to the aforementioned thymidine analogues to label most of the cells undergoing the S-phase of the cell cycle. I will also show how to infer, in an asynchronous cell population, the duration of the G₁, S, and G₂ phases, as well as the growth fraction and the span of the whole cell cycle on the base of some labeling schemes involving a single administration, continuous nucleotide analogue delivery, and double labeling with two thymidine analogues. In this context, the choice of the optimal dose of BrdU, CldU, IdU, and EdU to label S-phase cells is a pivotal aspect to produce neither cytotoxic effects nor alter cell cycle progression. I hope that the information presented in this review can be of use as a reference for researchers involved in the genesis of tissues and organs.