Spindle microtubule dysfunction and cancer predisposition

Unraveling the Molecular Complexity of Adenoid Cystic Carcinoma (ACC): A Comprehensive Exploration of Hub Genes, Protein-Protein Interaction (PPI) Networks, microRNA (miRNA) Involvement, and Drug-Gene Interactions (DGIs)

Background Adenoid cystic carcinoma (ACC) poses clinical challenges with its unique histology and potential for perineural invasion, recurrence, and distant metastases. Recent genomic advancements have unveiled key genetic alterations in ACC, offering insights into its pathogenesis. Aim This study aims to unravel the intricate molecular landscape of ACC through a comprehensive analysis of gene expression patterns. By integrating data from multiple microarray datasets, the study explores differentially expressed genes (DEGs), their functional enrichment, protein-protein interactions (PPI), hub genes, microRNA (miRNA) involvement, transcription factors, and potential drug-gene interactions. Methods Three microarray datasets (GSE88804, GSE153002, and GSE36820) related to ACC were selected from the Gene Expression Omnibus (GEO) repository. DEGs were identified using GEO2R and further analyzed for commonalities and differences. Functional enrichment analysis, including Gene Set Enrichment Analysis (GSEA), provided insights into biological processes, cellular components, molecular functions, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with ACC. PPI networks and hub genes were identified using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) (STRING Consortium, Lausanne, Switzerland) database and Cytoscape (Cytoscape Consortium, California, United States). The study also explored miRNAs, transcription factors, and potential drug-gene interactions. Results The integrated analysis revealed 339 common upregulated and 643 downregulated DEGs in ACC. Functional and pathway enrichment analyses unveiled the involvement of these genes in critical cellular processes, signaling cascades, and pathways. The PPI network, comprising 904 nodes and 4139 edges, highlighted the complexity of interactions. Hub genes, including KIF11, BUB1, and DLGAP5, were identified, shedding light on their pivotal roles in cell cycle regulation. The study also identified miRNAs (e.g., hsa-mir-7-5p and hsa-mir-138-5p) and transcription factors (e.g., E2F1 and TP53) associated with ACC. Drug-gene interactions have identified potential therapeutic options, including amsacrine and rucaparib. Conclusions The ACC gene expression highlights a nuanced molecular landscape, identifying pivotal hub genes such as KIF11 and CDK1 as potential therapeutic targets for ACC, given their roles in cell cycle progression. The dysregulation of microRNAs and transcription factors adds complexity to ACC's molecular profile. Exploration of drug-gene interactions reveals promising therapeutic strategies, involving FDA-approved drugs such as amsacrine and rucaparib, providing avenues for personalized interventions.

Mechanical coupling coordinates microtubule growth

During mitosis, kinetochore-attached microtubules form bundles (k-fibers) in which many filaments grow and shorten in near-perfect unison to align and segregate each chromosome. However, individual microtubules grow at intrinsically variable rates, which must be tightly regulated for a k-fiber to behave as a single unit. This exquisite coordination might be achieved biochemically, via selective binding of polymerases and depolymerases, or mechanically, because k-fiber microtubules are coupled through a shared load that influences their growth. Here, we use a novel dual laser trap assay to show that microtubule pairs growing in vitro are coordinated by mechanical coupling. Kinetic analyses show that microtubule growth is interrupted by stochastic, force-dependent pauses and indicate persistent heterogeneity in growth speed during non-pauses. A simple model incorporating both force-dependent pausing and persistent growth speed heterogeneity explains the measured coordination of microtubule pairs without any free fit parameters. Our findings illustrate how microtubule growth may be synchronized during mitosis and provide a basis for modeling k-fiber bundles with three or more microtubules, as found in many eukaryotes.

Mechanical coupling coordinates microtubule growth

During mitosis, kinetochore-attached microtubules form bundles (k-fibers) in which many filaments grow and shorten in near-perfect unison to align and segregate each chromosome. However, individual microtubules grow at intrinsically variable rates, which must be tightly regulated for a k-fiber to behave as a single unit. This exquisite coordination might be achieved biochemically, via selective binding of polymerases and depolymerases, or mechanically, because k-fiber microtubules are coupled through a shared load that influences their growth. Here, we use a novel dual laser trap assay to show that microtubule pairs growing in vitro are coordinated by mechanical coupling. Kinetic analyses show that microtubule growth is interrupted by stochastic, force-dependent pauses and indicate persistent heterogeneity in growth speed during non-pauses. A simple model incorporating both force-dependent pausing and persistent growth speed heterogeneity explains the measured coordination of microtubule pairs without any free fit parameters. Our findings illustrate how microtubule growth may be synchronized during mitosis and provide a basis for modeling k-fiber bundles with three or more microtubules, as found in many eukaryotes.

EMC3 regulates mesenchymal cell survival via control of the mitotic spindle assembly

Eukaryotic cells transit through the cell cycle to produce two daughter cells. Dysregulation of the cell cycle leads to cell death or tumorigenesis. Herein, we found a subunit of the ER membrane complex, EMC3, as a key regulator of cell cycle. Conditional deletion of Emc3 in mouse embryonic mesoderm led to reduced size and patterning defects of multiple organs. Emc3 deficiency impaired cell proliferation, causing spindle assembly defects, chromosome mis-segregation, cell cycle arrest at G2/M, and apoptosis. Upon entry into mitosis, mesenchymal cells upregulate EMC3 protein levels and localize EMC3 to the mitotic centrosomes. Further analysis indicated that EMC3 works together with VCP to tightly regulate the levels and activity of Aurora A, an essential factor for centrosome function and mitotic spindle assembly: while overexpression of EMC3 or VCP degraded Aurora A, their loss led to increased Aurora A stability but reduced Aurora A phosphorylation in mitosis.

Metallic nanoparticles as drug delivery system for the treatment of cancer

INTRODUCTION

The targeted delivery of anticancer agents to tumor is a major challenge because most of the drugs show off-target effect resulting in nonspecific cell death. Multifunctionalized metallic nanoparticles (NPs) are explored as new carrier system in the era of cancer therapeutics. Researchers investigated the potential of metallic NPs to target tumor cells by active and passive mechanisms, thereby reducing off-target effects of anticancer agents. Moreover, photocatalytic activity of upconversion nanoparticles (UCNPs) and the enhanced permeation and retention (EPR) effect have also gained wide potential in cancer treatment. Recent advancement in the field of nanotechnology highlights their potency for cancer therapy.

AREAS COVERED

This review summarizes the types of gold and silver metallic NPs with targeting mechanisms and their potentiality in cancer therapy.

EXPERT OPINION

Recent advances in the field of nanotechnology for cancer therapy offer high specificity and targeting efficiency. Targeting tumor cells through mechanistic pathways using metallic NPs for the disruption/alteration of molecular profile and survival rate of the tumor cells has led to an effective approach for cancer therapeutics. This alteration in the survival rate of the tumor cells might decrease the proliferation thereby resulting in more efficient management in the treatment of cancer.

Prognostic role of targeting protein for Xklp2 in solid tumors: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

The prognostic role of targeting protein for Xklp2 (TPX2) in solid tumors has been investigated in several researches, but the results remain controversial. Here we present a meta-analysis to systematically review the association between TPX2 expression levels and prognosis of human solid tumors.

METHODS

Studies published until December 2017 were searched in PubMed, Web of Science, and EBSCO, 13 studies (2134 patients) were collected for analysis. Odds ratios (ORs) for overall survival (OS) and disease-free survival (DFS) from individual studies were calculated by the application of Mantel-Haenszel random effect model. Pooled ORs were estimated by Z test. Publication bias and interstudy heterogeneity analyses were also performed.

RESULTS

TPX2 overexpression was associated with poor OS at 3 and 5 years [OR = 4.63, 95% confidence interval (CI): 3.27-6.56, P < .00001; OR = 4.05, 95% CI: 2.32-7.07, P < .00001, respectively] of solid tumors. Similar results were observed with DFS at 3 and 5 years (OR = 3.35, 95% CI: 1.83-6.14, P < .0001; OR = 2.94, 95% CI: 1.74-4.98, P < .0001, respectively). Subgroup analysis revealed that increased TPX2 expression was related to worse prognosis of gastric cancer and hepatocellular cancer, while irrelevant to esophageal squamous cell cancer at 5-year survival rate.

CONCLUSIONS

Overexpression of TPX2 is related to poor survival rate in most solid tumors, which indicates that the expression level of TPX2 is a significant prognostic parameter and potential therapeutic target in various solid tumors.

Silencing of long non-coding RNA SBDSP1 suppresses tumor growth and invasion in colorectal cancer

Long non-coding RNAs (lncRNAs) play critical roles in tumor development and progression. This study was undertaken to examine the expression and biological functions of a novel lncRNA SBDSP1 in colorectal cancer (CRC). Quantitative real-time PCR analysis was used to measure the expression of SBDSP1 in CRC tissues and cell lines. Knockdown of SBDSP1 via short hairpin RNA technology was performed to determine the roles of SBDSP1 in CRC cell growth, colony formation, cell cycle progression, migration, and invasion. The effect of SBDSP1 knockdown on tumorigenesis of CRC cells was investigated in a subcutaneous tumor mouse model. Western blot analysis was done to examine the involvement of signaling pathways in the action of SBDSP1. Notably, SBDSP1 was overexpressed in CRC tissues and cells relative to corresponding normal controls. Moreover, SBDSP1 expression was significantly greater in CRCs with nodal metastasis than in primary tumors (P=0.0259). Downregulation of SBDSP1 significantly inhibited cell proliferation, colony formation, migration, and invasion in SW480 and HCT116 cells, which was accompanied by suppression of Akt, ERK1/2, and STAT3 phosphorylation. SBDSP1-depleted cells showed a G0/G1 cell cycle arrest and deregulation of p21 and cyclin D1. In vivo studies confirmed that SBDSP1 downregulation retarded the growth of HCT116 xenogaft tumors. Altogether, SBDSP1 plays an essential role in CRC cell growth, invasion, and tumorigenesis, largely through inactivation of multiple signaling pathways. Therefore, targeting SBDSP1 may have therapeutic benefits in the treatment of CRC.

Anaphase asymmetry and dynamic repositioning of the division plane during maize meiosis

The success of an organism is contingent upon its ability to transmit genetic material through meiotic cell division. In plant meiosis I, the process begins in a large spherical cell without physical cues to guide the process. Yet, two microtubule-based structures, the spindle and phragmoplast, divide the chromosomes and the cell with extraordinary accuracy. Using a live-cell system and fluorescently labeled spindles and chromosomes, we found that the process self- corrects as meiosis proceeds. Metaphase spindles frequently initiate division off-center, and in these cases anaphase progression is asymmetric with the two masses of chromosomes traveling unequal distances on the spindle. The asymmetry is compensatory, such that the chromosomes on the side of the spindle that is farthest from the cell cortex travel a longer distance at a faster rate. The phragmoplast forms at an equidistant point between the telophase nuclei rather than at the original spindle mid-zone. This asymmetry in chromosome movement implies a structural difference between the two halves of a bipolar spindle and could allow meiotic cells to dynamically adapt to errors in metaphase and accurately divide the cell volume.

Cell cycle gene expression networks discovered using systems biology: Significance in carcinogenesis

The early stages of carcinogenesis are linked to defects in the cell cycle. A series of cell cycle checkpoints are involved in this process. The G1/S checkpoint that serves to integrate the control of cell proliferation and differentiation is linked to carcinogenesis and the mitotic spindle checkpoint is associated with the development of chromosomal instability. This paper presents the outcome of systems biology studies designed to evaluate if networks of covariate cell cycle gene transcripts exist in proliferative mammalian tissues including mice, rats, and humans. The GeneNetwork website that contains numerous gene expression datasets from different species, sexes, and tissues represents the foundational resource for these studies (www.genenetwork.org). In addition, WebGestalt, a gene ontology tool, facilitated the identification of expression networks of genes that co-vary with key cell cycle targets, especially Cdc20 and Plk1 (www.bioinfo.vanderbilt.edu/webgestalt). Cell cycle expression networks of such covariate mRNAs exist in multiple proliferative tissues including liver, lung, pituitary, adipose, and lymphoid tissues among others but not in brain or retina that have low proliferative potential. Sixty-three covariate cell cycle gene transcripts (mRNAs) compose the average cell cycle network with P = e(-13) to e(-36) . Cell cycle expression networks show species, sex and tissue variability, and they are enriched in mRNA transcripts associated with mitosis, many of which are associated with chromosomal instability.

Neuronal Nitric Oxide Synthase-Mediated Genotoxicity of 2-Methoxyestradiol in Hippocampal HT22 Cell Line

2-methoxyestradiol, metabolite of 17β-estradiol, is considered a potential anticancer agent, currently investigated in several clinical trials. This natural compound was found to be effective towards great number of cancers, including colon, breast, lung, and osteosarcoma and has been reported to be relatively non-toxic towards non-malignant cells. The aim of the study was to determine the potential neurotoxicity and genotoxicity of 2-methoxyestradiol at physiological and pharmacological relevant concentrations in hippocampal HT22 cell line. Herein, we determined influence of 2-methoxyestradiol on proliferation, inhibition of cell cycle, induction of apoptosis, and DNA damage in the HT22 cells. The study was performed using imaging cytometry and comet assay techniques. Herein, we demonstrated that 2-methoxyestradiol, at pharmacologically and also physiologically relevant concentrations, increases nuclear localization of neuronal nitric oxide synthase. It potentially results in DNA strand breaks and increases in genomic instability in hippocampal HT22 cell line. Thus, we are postulating that naturally occurring 2-methoxyestradiol may be considered a physiological modulator of neuron survival.

LG308, a Novel Synthetic Compound with Antimicrotubule Activity in Prostate Cancer Cells, Exerts Effective Antitumor Activity

Microtubule plays many different essential roles in the process of tumorigenesis in many eukaryotes, and targeting mitotic progression by disturbing microtubule dynamics is used as a common strategy for cancer treatment. Microtubule-targeted drugs, including paclitaxel and Vinca alkaloids, were previously considered to work primarily by increasing or decreasing the cellular microtubule mass. The tubulin/microtubule system, which is an integral component of the cytoskeleton, is a therapeutic target for prostate cancer. In this study, we found a novel synthetic compound, 8-fluoro-N-phenylacetyl-1, 3, 4, 9-tetrahydro-β-carboline (LG308), which disrupted the microtubule organization via inhibiting the polymerization of microtubule in PC-3M and LNCaP prostate cancer cell lines. Further study proved that LG308 induced mitotic phase arrest and inhibited G2/M progression significantly in LNCaP and PC-3M cell lines in a dose-dependent manner, and these were associated with the upregulation of cyclin B1 and mitotic marker MPM-2 and the dephosphorylation of cdc2. Besides, the cell proliferation and colony formation of PC-3M and LNCaP cells were effectively inhibited by LG308. Furthermore, LG308 induced apoptosis and cell death in PC-3M and LNCaP cell lines in vitro. In vivo, LG308 dramatically suppressed the growth and metastasis of prostate cancer in both xenograft and orthotopic models. All these data indicate that LG308 is a promising anticancer candidate with antimitotic activity for the treatment of prostate cancer.

DNA strand breaks induced by nuclear hijacking of neuronal NOS as an anti-cancer effect of 2-methoxyestradiol

2-Methoxyestradiol (2-ME) is a physiological metabolite of 17β-estradiol. At pharmacological concentrations, 2-ME inhibits colon, breast and lung cancer in tumor models. Here we investigated the effect of physiologically relevant concentrations of 2-ME in osteosarcoma cell model. We demonstrated that 2-ME increased nuclear localization of neuronal nitric oxide synthase, resulting in nitro-oxidative DNA damage. This in turn caused cell cycle arrest and apoptosis in osteosarcoma cells. We suggest that 2-ME is a naturally occurring hormone with potential anti-cancer properties.