Identification of Hub Genes in Atypical Teratoid/Rhabdoid Tumor by Bioinformatics Analyses

RRM2 inhibition alters cell cycle through ATM/Rb/E2F1 pathway in atypical teratoid rhabdoid tumor

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is an aggressive brain tumor that mainly affects young children. Our recent study reported a promising therapeutic strategy to trigger DNA damage, impede homologous recombination repair, and induce apoptosis in ATRT cells by targeting ribonucleotide reductase regulatory subunit M2 (RRM2). COH29, an inhibitor of RRM2, effectively reduced tumor growth and prolonged survival in vivo. Herein, we explored the underlying mechanisms controlling these functions to improve the clinical applicability of COH29 in ATRT.

METHODS

Molecular profiling of ATRT patients and COH29-treated cells was analyzed to identify the specific signaling pathways, followed by validation using a knockdown system, flow cytometry, q-PCR, and western blot.

RESULTS

Elevated E2F1 and its signaling pathway were correlated with poor prognosis. RRM2 inhibition induced DNA damage and activated ATM, which reduced Rb phosphorylation to promote Rb-E2F1 interaction and hindered E2F1 functions. E2F1 activity suppression led to decreased E2F1-dependent target expressions, causing cell cycle arrest in the G1 phase, decreased S phase cells, and blocked DNA damage repair.

CONCLUSION

Our study highlights the role of ATM/Rb/E2F1 pathway in controlling cell cycle arrest and apoptosis in response to RRM2 inhibition-induced DNA damage. This provides insight into the therapeutic benefits of COH29 and suggests targeting this pathway as a potential treatment for ATRT.

Targeting of RRM2 suppresses DNA damage response and activates apoptosis in atypical teratoid rhabdoid tumor

BACKGROUND

Atypical teratoid rhabdoid tumors (ATRT) is a rare but aggressive malignancy in the central nervous system, predominantly occurring in early childhood. Despite aggressive treatment, the prognosis of ATRT patients remains poor. RRM2, a subunit of ribonucleotide reductase, has been reported as a biomarker for aggressiveness and poor prognostic conditions in several cancers. However, little is known about the role of RRM2 in ATRT. Uncovering the role of RRM2 in ATRT will further promote the development of feasible strategies and effective drugs to treat ATRT.

METHODS

Expression of RRM2 was evaluated by molecular profiling analysis and was confirmed by IHC in both ATRT patients and PDX tissues. Follow-up in vitro studies used shRNA knockdown RRM2 in three different ATRT cells to elucidate the oncogenic role of RRM2. The efficacy of COH29, an RRM2 inhibitor, was assessed in vitro and in vivo. Western blot and RNA-sequencing were used to determine the mechanisms of RRM2 transcriptional activation in ATRT.

RESULTS

RRM2 was found to be significantly overexpressed in multiple independent ATRT clinical cohorts through comprehensive bioinformatics and clinical data analysis in this study. The expression level of RRM2 was strongly correlated with poor survival rates in patients. In addition, we employed shRNAs to silence RRM2, which led to significantly decrease in ATRT colony formation, cell proliferation, and migration. In vitro experiments showed that treatment with COH29 resulted in similar but more pronounced inhibitory effect. Therefore, ATRT orthotopic mouse model was utilized to validate this finding, and COH29 treatment showed significant tumor growth suppression and prolong overall survival. Moreover, we provide evidence that COH29 treatment led to genomic instability, suppressed homologous recombinant DNA damage repair, and subsequently induced ATRT cell death through apoptosis in ATRT cells.

CONCLUSIONS

Collectively, our study uncovers the oncogenic functions of RRM2 in ATRT cell lines, and highlights the therapeutic potential of targeting RRM2 in ATRT. The promising effect of COH29 on ATRT suggests its potential suitability for clinical trials as a novel therapeutic approach for ATRT.

A mini-review of the role of condensin in human nervous system diseases

Mitosis and meiosis are crucial life activities that transmit eukaryotic genetic information to progeny in a stable and orderly manner. The formation and appearance of chromosomes, which are derived from chromatin, are the preconditions and signs of mitosis. When entering mitosis, interphase loose chromatin is highly spiralized and folded to form compact chromosomes. In recent years, it has been found that in addition to the well-known DNA, histones, and topoisomerase, a large protein complex called condensin plays an important role in the process of chromosome formation. Numerous studies have shown that the abnormal function of condensin can lead to incomplete or excessive concentration of chromatin, as well as disorder of genome organization process, abnormal transmission of genetic information, and ultimately lead to various diseases of individual, especially in nervous system diseases. In this review, the biological function of condensin and the potential pathogenic mechanism of condensin in nervous system diseases are briefly summarized. Therefore, the investigation of these mechanisms makes a significant contribution to the understanding of those related diseases and provides new ideas for clinical treatments.

Analysis of Hub Genes Involved in Distinction Between Aged and Fetal Bone Marrow Mesenchymal Stem Cells by Robust Rank Aggregation and Multiple Functional Annotation Methods

Stem cells from fetal tissue protect against aging and possess greater proliferative capacity than their adult counterparts. These cells can more readily expand in vitro and senesce later in culture. However, the underlying molecular mechanisms for these differences are still not fully understood. In this study, we used a robust rank aggregation (RRA) method to discover robust differentially expressed genes (DEGs) between fetal bone marrow mesenchymal stem cells (fMSCs) and aged adult bone marrow mesenchymal stem cells (aMSCs). Multiple methods, including gene set enrichment analysis (GSEA), Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for functional annotation of the robust DEGs, and the results were visualized using the R software. The hub genes and other genes with which they interacted directly were detected by protein–protein interaction (PPI) network analysis. Correlation of gene expression was measured by Pearson correlation coefficient. A total of 388 up-regulated and 289 down-regulated DEGs were identified between aMSCs and fMSCs. We found that the down-regulated genes were mainly involved in the cell cycle, telomerase activity, and stem cell proliferation. The up-regulated DEGs were associated with cell adhesion molecules, extracellular matrix (ECM)–receptor interactions, and the immune response. We screened out four hub genes, MYC, KIF20A, HLA-DRA, and HLA-DPA1, through PPI-network analysis. The MYC gene was negatively correlated with TXNIP, an age-related gene, and KIF20A was extensively involved in the cell cycle. The results suggested that MSCs derived from the bone marrow of an elderly donor present a pro-inflammatory phenotype compared with that of fMSCs, and the HLA-DRA and HLA-DPA1 genes are related to the immune response. These findings provide new insights into the differences between aMSCs and fMSCs and may suggest novel strategies for ex vivo expansion and application of adult MSCs.

Genetic and Clinical Characterization of HOXB2 in Glioma

Background

Glioma is a highly aggressive and heterogeneous cancer with poor survival rates. Homeobox (HOX) genes are transcription factors that play pivotal roles in many aspects of cellular physiology, embryonic development, and tissue homeostasis. Mutations in HOX genes can lead to increased cancer predisposition. Abnormal expression of HOXB2 may result in the development and progression of tumors. However, its prognostic value and mechanism of dysregulation remain unclear.

Methods

The present study included 1001 glioma patients. The correlations between the expression of HOXB2 and subgroups of glioma were investigated by t-test analyses. The prognostic value of HOXB2 was explored by Kaplan–Meier analysis as well as univariate and multivariate Cox analyses. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were employed to detect the biological function of HOXB2 in glioma. CCK-8 and transwell assays were performed to determine the role of HOXB2 in cell proliferation and invasion.

Results

HOXB2 was positively correlated with tumor grade and enriched in patients with isocitrate dehydrogenase 1 wild-type and age >41 years. HOXB2 was identified as an independent prognostic biomarker in glioma patients. HOXB2 was associated with cell invasion and promoted the proliferation of glioma cells in vitro.

Conclusion

HOXB2 is an independent prognostic factor and contributes to tumor invasion in glioma patients.

microRNA-139-3p Inhibits Malignant Behaviors of Laryngeal Cancer Cells via the KDM5B/SOX2 Axis and the Wnt/β-Catenin Pathway

Background

Laryngeal cancer (LCA) is a common head and neck cancer. Lysine demethylase 5B (KDM5B) knockdown is expected as a new target for cancer prevention. We investigated the molecular mechanism of KDM5B in LCA.

Materials and Methods

The levels of KDM5B, microRNA (miR)-139-3p and high-mobility-group box 2 (SOX2) in LCA tissues and cells, normal tissues and cells were detected. The effect of KDM5B on LCA was evaluated. The upstream miR of KDM5B and the downstream gene and pathway of KDM5B were predicted and their effects on LCA were analyzed. The Wnt/β-catenin pathway-specific activator agonist was delivered into LCA cells expressing miR-139-3p mimic to evaluate the role of the Wnt/β-catenin pathway.

Results

KDM5B was highly expressed in LCA, and inhibition of KDM5B suppressed LCA progression. miR-139-3p, downregulated in LCA tissues, was a regulatory miR of KDM5B. Overexpression of miR-139-3p significantly inhibited the malignant biological behaviors of LCA cells. KDM5B promoted SOX2 expression via histone demethylation. SOX2 was highly expressed in LCA, and overexpression of SOX2 promoted LCA progression by inducing the Wnt/β-catenin pathway. Activated Wnt/β-catenin pathway attenuated the inhibitory effect of miR-139-3p mimic on the malignant biological behaviors of LCA cells.

Conclusion

miR-139-3p overexpression inhibited LCA development via regulating the KDM5B/SOX2 axis and inhibiting the Wnt/β-catenin pathway.

Neferine induces apoptosis by modulating the ROS‑mediated JNK pathway in esophageal squamous cell carcinoma

Current treatments for esophageal squamous cell carcinoma (ESCC) have limited efficacy. Therefore, the development of novel therapeutic targets to effectively manage the disease and boost survival rates is imperative Neferine, a natural product extracted from Nelumbo nucifera (lotus) leaves, has been revealed to inhibit the growth of hepatocarcinoma, breast cancer and lung cancer cells. However, its effect on ESCC is unknown. In the present study, it was revealed that neferine exerted anti‑proliferative effects in ESCC. It was also revealed that it triggered arrest of the G2/M phase and enhanced apoptosis of ESCC cell lines. Moreover, its ability to trigger accumulation of reactive oxygen species (ROS) and activate the c‑Jun N‑terminal kinase (JNK) pathway was demonstrated. Further study revealed how N‑acetyl cysteine (NAC), a ROS inhibitor, attenuated these effects, demonstrating that ROS and JNK inhibitors mediated a marked reversal of neferine‑triggered cell cycle arrest and apoptosis in ESCC cells. Finally, it was revealed that neferine was involved in the inhibition of Nrf2, an antioxidant factor. Collectively, these findings demonstrated the antitumor effect of neferine in ESCC, through the ROS‑mediated JNK pathway and inhibition of Nrf2, indicating its potential as a target for development of novel and effective therapeutic agents against ESCC.