Homeobox B2 is a potential prognostic biomarker of glioblastoma

Mechanistic insights into super-enhancer-driven genes as prognostic signatures in patients with glioblastoma

BACKGROUND

Glioblastoma (GBM) is one of the most common malignant brain tumors in adults and is characterized by high aggressiveness and rapid progression, poor treatment, high recurrence rate, and poor prognosis. Although super-enhancer (SE)-driven genes haven been recognized as prognostic markers for several cancers, whether it can be served as effective prognostic markers for patients with GBM has not been evaluated.

METHODS

We first combined histone modification data with transcriptome data to identify SE-driven genes associated with prognosis in patients with GBM. Second, we developed a SE-driven differentially expressed genes (SEDEGs) risk score prognostic model by univariate Cox analysis, KM survival analysis, multivariate Cox analysis and least absolute shrinkage and selection operator (LASSO) regression. Its reliability in predicting was verified by two external data sets. Third, through mutation analysis, immune infiltration, we explored the molecular mechanisms of prognostic genes. Next, Genomics of Drug Sensitivity in Cancer (GDSC) and the Connectivity Map (cMap) database were employed to assess different sensitivities to chemotherapeutic agents and small-molecule drug candidates between high- and low-risk patients. Finally, SEanalysis database was chosen to identify SE-driven transcription factors (TFs) regulating prognostic markers which will reveal a potential SE-driven transcriptional regulatory network.

RESULTS

First, we developed a 11-gene risk score prognostic model (NCF2, MTHFS, DUSP6, G6PC3, HOXB2, EN2, DLEU1, LBH, ZEB1-AS1, LINC01265, and AGAP2-AS1) selected from 1,154 SEDEGs, which is not only an independent prognostic factor for patients, but also can effectively predict the survival rate of patients. The model can effectively predict 1-, 2- and 3-year survival of patients and was validated in external Chinese Glioma Genome Atlas (CGGA) and Gene Expression Omnibus (GEO) datasets. Second, the risk score was positively correlated with the infiltration of regulatory T cell, CD4 memory activated T cell, activated NK cell, neutrophil, resting mast cell, M0 macrophage, and memory B cell. Third, we found that high-risk patients showed higher sensitivity than low-risk patients to both 27 chemotherapeutic agents and 4 small-molecule drug candidates which might benefit further precision therapy for GBM patients. Finally, 13 potential SE-driven TFs imply how SE regulates GBM patient's prognosis.

CONCLUSION

The SEDEG risk model not only helps to elucidate the impact of SEs on the course of GBM, but also provides a bright future for prognosis determination and choice of treatment for GBM patients.

Development of Prognostic Indicator Based on AU-Rich Elements-Related Genes in Glioblastoma

BACKGROUND

AREs (AU-rich elements) are important cis-acting short sequences in the 3'UTR (3'-untranslated region) that affect messenger RNA stability and translation. However, there were no systematic researches about AREs-related genes to predict the survival of patients with GBM (glioblastoma).

METHODS

Differentially expressed genes were acquired from The Cancer Genome Atlas and Chinese Glioma Genome Atlas databases. Differentially expressed AREs-related genes were filtered by overlapping differentially expressed genes and AREs-related genes. The prognostic genes were selected to construct a risk model. Patients with GBM were categorized into 2 risk groups depending on the medium value of risk score. Gene Set Enrichment Analysis was performed to explore the potential biological pathways. We explored the correlation between the risk model and immune cells. The chemotherapy sensitivity was predicted in different risk groups.

RESULTS

A risk model was constructed by 10 differentially expressed AREs-related genes (GNS, ANKH, PTPRN2, NELL1, PLAUR, SLC9A2, SCARA3, MAPK1, HOXB2, and EN2), and it could accurately predict the prognosis of patients with GBM. Higher risk scores for patients with GBM had a lower survival probability. The predictive power of risk model was decent. The risk score and treatment type were regarded as independent prognostic indicators. The mainly Gene Set Enrichment Analysis enrichment pathways were primary immunodeficiency and chemokine signaling pathway. Six immune cells were significant different in the 2 risk groups. There were higher abundance of macrophages M2 and neutrophils and higher sensitivity of 11 chemotherapy drugs in the high-risk group.

CONCLUSIONS

The 10 biomarkers might be important prognostic markers and potential therapeutic targets for patients with GBM.

High expression of homeobox B2 predicts poor survival of colon adenocarcinoma by enhancing tumor proliferation and invasion

OBJECTIVE

Homeobox B2 (HOXB2) is known to be correlated with the development and prognosis of various cancers. However, its role in colon cancer remains unclear.

AIMS

In this study, we explored the prognostic value of HOXB2 in colon adenocarcinoma (COAD).

METHODS

A total of 264 colon adenocarcinoma cases were retrospectively enrolled to evaluate HOXB2 expression and clinical significance. Chi-square test was applied to identify relationship between clinical features and HOXB2 expression. The effect of HOXB2 expression and clinical features on the survival of COAD patients was evaluated using Kaplan-Meier and Cox regression analyses. Cellular assays and mice models were conducted to validate the tumor-related role of HOXB2 in COAD.

RESULTS

Higher expression of HOXB2 in COAD tissues was significantly associated with tumor size, invasion depth, and lymph node metastasis (all P < 0.05). Univariate and multivariate analyses showed that high expression of HOXB2 was significantly correlated with a poor overall survival. In vitro cellular assays combined with knockdown strategies demonstrated that HOXB2 can promote tumor proliferation and invasion of COAD, which was further confirmed by in vivo xenograft experiments.

CONCLUSIONS

HOXB2 may be a valuable biomarker and potential therapeutic target for the treatment of COAD.

Transcription factor HOXB2 upregulates NUSAP1 to promote the proliferation, invasion and migration of nephroblastoma cells via the PI3K/Akt signaling pathway

The transcription factor homeobox protein Hox-B2 (HOXB2) and its downstream factor nucleolar and spindle-associated protein 1 (NUSAP1) play important regulatory roles in cell proliferation, invasion and migration. However, their effects and specific mechanisms in nephroblastoma have not been previously investigated, to the best of our knowledge. Therefore, in the present study, the mRNA and protein expression levels of HOXB2 and NUSAP1 were determined in nephroblastoma cells using reverse transcription-quantitative PCR and western blot analyses, respectively. Furthermore, cell transfection experiments were carried out to knock down NUSAP1 and overexpress HOXB2 in nephroblastoma cell lines. The proliferative, invasive and migratory abilities of nephroblastoma cells were assessed by MTT, EdU, colony formation, wound healing and Transwell assays. In addition, the JASPAR website was used to predict the association between HOXB2 and NUSAP1, which was further verified by dual-luciferase reporter and chromatin immunoprecipitation assays. Finally, the expression levels of the PI3K/Akt signaling pathway-related proteins were measured by western blot analysis. The results showed that the expression of NUSAP1 was abnormally upregulated in nephroblastoma cell lines. However, NUSAP1 silencing attenuated the proliferation, invasion and migration abilities of nephroblastoma cells. The results also suggested that HOXB2 could transcriptionally activate NUSAP1. Therefore, HOXB2 overexpression abrogated the inhibitory effect of NUSAP1 silencing on the proliferation and metastasis of nephroblastoma cells, possibly via the PI3K/Akt signaling pathway. The aforementioned findings indicated that HOXB2 may upregulate NUSAP1 to promote the proliferation, invasion and migration of nephroblastoma cells via the PI3K/Akt signaling pathway.

Molecular implications of HOX genes targeting multiple signaling pathways in cancer

Homeobox (HOX) genes encode highly conserved homeotic transcription factors that play a crucial role in organogenesis and tissue homeostasis. Their deregulation impacts the function of several regulatory molecules contributing to tumor initiation and progression. A functional bridge exists between altered gene expression of individual HOX genes and tumorigenesis. This review focuses on how deregulation in the HOX-associated signaling pathways contributes to the metastatic progression in cancer. We discuss their functional significance, clinical implications and ascertain their role as a diagnostic and prognostic biomarker in the various cancer types. Besides, the mechanism of understanding the theoretical underpinning that affects HOX-mediated therapy resistance in cancers has been outlined. The knowledge gained shall pave the way for newer insights into the treatment of cancer.

Estrogen suppresses HOXB2 expression via ERα in breast cancer cells

The expression of HOXB2, a homeobox transcription factor, is altered in a variety of solid tumors. Using an in vivo screen to identify regulators of breast tumor growth in murine mammary fat pads, Boimel and co-workers recently identified HOXB2 as a tumor suppressor. However, the mechanistic underpinnings of its role in breast cancer is not understood. Given the emerging interaction of estrogen-regulated gene expression and altered HOX gene expression network in the pathophysiology of breast cancer, this study addressed the relationship between estrogen signaling and HOXB2 expression. Using a mouse model and human breast cancer cell lines, we show that estrogen suppresses HOXB2 expression. Suppression of HOXB2 by PPT, a known ERα agonist, in MCF-7 and T47D cells indicated the involvement of ERα, which was confirmed by siRNA-mediated ERα knockdown experiments. In-silico analysis of the upstream promoter region revealed the presence of three putative EREs. Chromatin immunoprecipitation experiments showed that upon estrogen binding, ERα engaged with EREs in the 5' upstream region of HOXB2 in MCF-7 and T47D cells. Future investigations should address the implications of estrogen-mediated suppression on the proposed tumor suppressor function of HOXB2.