Upregulation of BTG1 enhances the radiation sensitivity of human breast cancer in vitro and in vivo

Single-cell combined with bulk-RNA data reveal a pattern related to angiogenesis in breast cancer patients: Individualized medicine

Angiogenesis contributes to tumor progression, aggressive behavior, and metastasis. Although several endothelial dysfunction genes (angiogenesis-related genes [ARGs]) have been identified as diagnostic biomarkers of breast cancer in a few studies, the mixed effects of ARGs have not been thoroughly investigated. The RNA sequencing data and patient survival datasets of breast cancer were obtained for further analysis. MSigDB website includes angiogenesis-related mechanisms. The consensus clustering analysis identifies 1082 breast cancer patients as three clusters. differential expression genes (DEGs) were identified by limma package. GO combined with gene set enrichment analysis (GSEA) to identify cytogenetic functions between two predefined clusters. Then Serpin Family F Member 1 (SERPINF1), angiomotin (AMOT), promyelocytic leukemia (PML), and BTG anti-proliferation factor 1 (BTG) were selected to construct prediction models using random forest survival analysis. External validation was performed using the GSE58812 triple-negative breast cancer cohort as the validation set. The median scoring system was used to discern the high- and low-risk groups, and there was a significant difference in their diagnostic results. Immunological infiltration scores were calculated using single sample gene set enrichment analysis (ssGSEA) and xCell algorithms, and consciousness scores were calculated using the R package "oncoPredict" for drugs in the Genomics of Drug Sensitivity in Cancer (GDSC) database. In addition, the single-cell analysis of seven triple-negative breast cancers using scRNA-seq information from GSE118389 demonstrated the interpretation of SERPINF1, AMOT, PML, and BTG1. In conclusion, this investigation engineered ARG-centric disease paradigms that not only prognosticated prospective therapeutic compounds, but also projected their mechanistic trajectories, thereby facilitating the proposition of tailored treatments within diverse patient cohorts diagnosed with breast cancer.

Targeting a novel circITCH/miR-421/BTG1 axis is effective to suppress the malignant phenotypes in hepatocellular carcinoma (HCC) cells

Circular RNA-based competing endogenous RNA (ceRNA) networks contribute to the initiation and development of various types of cancer, including hepatocellular carcinoma (HCC). Although a novel circular RNA itchy E3 ubiquitin protein ligase (circITCH) is identified as a tumor suppressor in HCC, its detailed molecular mechanisms have not been fully delineated. The present study was designed to resolve this issue, and we firstly verified that circITCH suppressed the malignant phenotypes in HCC cells by regulating a novel miR-421/B-cell translocation gene 1 (BTG1) axis. Specifically, through performing the Real-Time qPCR analysis, we noticed that circITCH expression in HCC tumor tissues or cell lines were significantly lower than that in adjacent normal tissues or normal hepatocytes, and the expression levels of circITCH were negatively correlated with tumor size and TNM stage in HCC patients. Next, our functional experiments confirmed that overexpression of circITCH induced cell cycle arrest and apoptosis, and reduced cell viability and colony forming ability in Hep3B and Huh7 cells. Mechanically, bioinformatics analysis, RNA immunoprecipitation and luciferase reporter assay demonstrated that circITCH served as RNA sponges for miR-421 to elevate BTG1 levels in HCC cells. The rescuing experiments verified that upregulation of miR-421 promoted cell viability and colony formation, and reduced apoptosis, which were abrogated by overexpression of circITCH or BTG1. In conclusion, this study identified a novel circITCH/miR-421/BTG1 axis that restrained the development of HCC, and our findings provided novel biomarkers for the treatment of this disease.

Development and validation of a combined hypoxia and ferroptosis prognostic signature for breast cancer

Background

Hypoxia is involved in tumor biological processes and disease progression. Ferroptosis, as a newly discovered programmed cell death process, is closely related to breast cancer (BC) occurrence and development. However, reliable prognostic signatures based on a combination of hypoxia and ferroptosis in BC have not been developed.

Method

We set The Cancer Genome Atlas (TCGA) breast cancer cohort as training set and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) BC cohort as the validation set. Least Absolute Shrinkage and Selection Operator (LASSO) and COX regression approaches were used to construct ferroptosis-related genes (FRGs) and hypoxia-related genes (HRGs) prognostic signature (HFRS). The CIBERSORT algorithm and ESTIMATE score were used to explore the relationship between HFRS and tumor immune microenvironment. Immunohistochemical staining was used to detect protein expression in tissue samples. A nomogram was developed to advance the clinical application of HFRS signature.

Results

Ten ferroptosis-related genes and hypoxia-related genes were screened to construct the HFRS prognostic signature in TCGA BC cohort, and the predictive capacity was verified in METABRIC BC cohort. BC patients with high-HFRS had shorter survival time, higher tumor stage, and a higher rate of positive lymph node. Moreover, high HFRS was associated with high hypoxia, ferroptosis, and immunosuppression status. A nomogram that was constructed with age, stage, and HFRS signature showed a strong prognostic capability to predict overall survival (OS) for BC patients.

Conclusion

We developed a novel prognostic model with hypoxia and ferroptosis-related genes to predict OS, and characterize the immune microenvironment of BC patients, which might provide new cures for clinical decision-making and individual treatment of BC patients.

The roles of BTG1 mRNA expression in cancers: A bioinformatics analysis

BTG1 (B-cell translocation gene 1) may inhibit proliferation and cell cycle progression, induce differentiation, apoptosis, and anti-inflammatory activity. The goal of this study was to clarify the clinicopathological and prognostic significances of BTG1 mRNA expression and related signal pathways in cancers. Using the Oncomine, TCGA (the cancer genome atlas), xiantao, UALCAN (The University of ALabama at Birmingham Cancer data analysis Portal), and Kaplan-Meier plotter databases, we undertook a bioinformatics study of BTG1 mRNA expression in cancers. BTG1 expression was lower in gastric, lung, breast and ovarian cancer than normal tissue due to its promoter methylation, which was the opposite to BTG1 expression. BTG1 expression was positively correlated with dedifferentiation and histological grading of gastric cancer (p < 0.05), with squamous subtype and young age of lung cancer (p < 0.05), with infrequent lymph node metastasis, low TNM staging, young age, white race, infiltrative lobular subtype, Her2 negativity, favorable molecular subtyping, and no postmenopause status of breast cancer (p < 0.05), and with elder age, venous invasion, lymphatic invasion, and clinicopathological staging of ovarian cancer (p < 0.05). BTG1 expression was negatively correlated with favorable prognosis of gastric, lung or ovarian cancer patients, but the converse was true for breast cancer (p < 0.05). KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that the top signal pathways included cytokine-cytokine receptor interaction, cell adhesion molecules, chemokine, immune cell receptor and NF (nuclear factor)-κB signal pathways in gastric and breast cancer. The top hub genes mainly contained CD (cluster of differentiation) antigens in gastric cancer, FGF (fibroblast growth factor)-FGFR (FGF receptor) in lung cancer, NADH (nicotinamide adenine dinucleotide): ubiquinone oxidoreductase in breast cancer, and ribosomal proteins in ovarian cancer. BTG1 expression might be employed as a potential marker to indicate carcinogenesis and subsequent progression, even prognosis.

18F-FDG Micro PET/CT imaging to evaluate the effect of BRCA1 knockdown on MDA-MB231 breast cancer cell radiosensitivity

•

BRCA1 gene knockdown improves the radiosensitivity of breast cancer cells.

•

BRCA1 gene knockdown combination with radiotherapy downregulates multiple biomarkers of poor prognosis.

•

18F-FDG Micro PET/CT imaging was able to evaluate the radiosensitizing effect of the BRCA1 gene in vitro experiment.

Objective

Radioresistance of tumor cells is a major factor associated with failure of radiotherapy (RT). This study aimed to investigate the effect of BRCA1 knockdown on MDA-MB231 breast cancer cell radiosensitivity.

Materials and methods

Short hairpin RNA (shRNA) was used to knockdown BRCA1 gene in MDA-MB231 cells. Cell viability and proliferative capacity were assessed by CCK-8 and colony formation assays, respectively. We established xenograft models in nude mice to evaluate tumor volume and tumor weight. The mice were imaged by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) before and after RT to evaluate changes in maximum standardized uptake value (SUV_max) and tumor SUV_max/muscle SUV_max (TMR). Changes in HIF-1α, Glut-1 and Ki-67 were analyzed and the correlation between ¹⁸F-FDG uptake and tumor biology was analyzed.

Results

Compared with the control cells, RT significantly reduced cell viability and colony formation capacity in cells with the BRCA1 gene knockdown. In vivo assays showed that there was obvious delay in the tumor growth in the shBRCA1+RT group compared with the control group. ¹⁸F-FDG Micro PET/CT indicated a reduction in glucose metabolism in the shBRCA1+RT group, with statistically significant differences in both the SUV_max and TMR. The data showed the expression of HIF-1α, Glut-1 and Ki-67 was downregulated in the shBRCA1+RT group, and both SUVmax and TMR had significant correlation with tumor biology.

Conclusion

These results demonstrated that BRCA1 knockdown improves the sensitivity of MDA-MB231 breast cancer cells to RT. In addition, ¹⁸F-FDG PET/CT imaging allows non-invasive analysis of tumor biology and assessment of radiosensitivity.

Reactive oxygen species may influence on the crossroads of stemness, senescence, and carcinogenesis in a cell via the roles of APRO family proteins

Excessive reactive oxygen species (ROS) may cause oxidative stress which is involved in aging and in the pathogenesis of various human diseases. Whereas unregulated levels of the ROS may be harmful, regulated basal level of ROS are even necessary to support cellular functions as a second messenger for homeostasis under physiological conditions. Therefore, redox medicine could develop as a new therapeutic concept for human health-benefits. Here, we introduce the involvement of ROS on the crossroads of stemness, senescence, and carcinogenesis in a stem cell and cancer cell biology. Amazingly, the anti-proliferative (APRO) family anti-proliferative proteins characterized by immediate early growth responsive genes may also be involved in the crossroads machinery. The biological functions of APRO proteins (APROs) seem to be quite intricate, however, which might be a key modulator of microRNAs (miRNAs). Given the crucial roles of ROS and APROs for pathophysiological functions, upcoming novel therapeutics should include vigilant modulation of the redox state. Next generation of medicine including regenerative medicine and/or cancer therapy will likely comprise strategies for altering the redox environment with the APROs via the modulation of miRNAs as well as with the regulation of ROS of cells in a sustainable manner.

Obesity-induced upregulation of microRNA-183-5p promotes hepatic triglyceride accumulation by targeting the B-cell translocation gene 1

AIMS

Obesity is recognized as a risk factor for many metabolic disorders, particularly nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanism is still poorly understood. Several lines of evidence indicate that microRNA (miRNA) is a key regulator of lipid metabolism. In this study, we investigated the role of miR-183-5p in the development of NAFLD.

METHODS

The expression levels of miR-183-5p and B-cell translocation gene 1 (Btg1) were determined by quantitative real-time PCR and histological analysis in livers of obese mice and cell models induced with palmitic acid (PA), respectively. AML12 cells were treated with PA in the presence or absence of miR-183-5p mimics or inhibitor. Moreover, a Luciferase reporter assay was used to determine whether Btg1 is the direct target of miR-183-5p. Protein levels of BTG1 were estimated using western blotting.

KEY FINDINGS

Expression of miR-183-5p was increased in the livers of three murine models and also in the AML12 cell model. Overexpression of miR-183-5p in the cell model and mice led to hepatic triglyceride (TG) accumulation and upregulation of lipogenic genes, whereas inhibition of miR-183-5p in the cell model improved hepatic TG accumulation. Mechanistically, we further identified Btg1 as a direct target gene of miR-183-5p.

SIGNIFICANCE

Our findings revealed that miR-183-5p affected the regulation of hepatic TG homeostasis, which may provide a potential therapeutic target for hepatosteatosis.

Expression of B Cell Translocation Gene 1 Protein in Colon Carcinoma and its Clinical Significance

BACKGROUND

Colon cancer is one of the most common malignant tumors, and B cell Translocation Gene (BTG)1 is involved in the occurrence and development of colon cancer, however, the underlying molecular mechanism remains unclear.

OBJECTIVE

In this study, we investigated the expression of BTG1 protein in colon cancer, and its association with clinicopathology and prognosis.

METHODS

The tumor specimens from 59 patients with colon cancer who had undergone radical colectomy were selected as the observation group. Para-carcinoma tissues from the same patients were selected as the control group. The expressions of BTG1 mRNA and protein in the specimen of two groups were analyzed by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Western blot. According to the immunohistochemical results, the patients were divided into BTG1-negative and BTG1-positive groups. The postoperative cumulative survival rate in the two groups was analyzed. The association of the expression of BTG1 protein with the clinicopathological features and postoperative survival was investigated.

RESULTS

Compared with the control group, the expression levels of BTG1 mRNA and BTG1 protein were significantly decreased in the observation group (P < 0.05). Immunohistochemical analysis revealed that there were 12 positive tumor samples and 47 negative samples. The expression of BTG1 was negatively associated with the degree of differentiation and lymphatic metastasis. The cumulative survival rate of BTG1-positive patients was significantly increased compared with that of BTG1- negative patients (P < 0.05). Stepwise Cox regression analysis showed that lymphatic metastasis, tumor size and BTG1 expression level were independent prognostic factors for overall survival in patients with colon cancer.

CONCLUSION

BTG1 protein in colon cancer tissues were expressed at low levels, which was associated with the clinicopathological features, postoperative recurrence and survival of patients.

BTG1 inhibits malignancy as a novel prognosis signature in endometrial carcinoma

Background

Endometrial carcinoma (EC) is one of the three major malignant tumors of the female reproductive system. In recent years, the incidence and mortality rate of EC have increased. B-cell translocation gene 1 (BTG1) is an anti-proliferation gene that regulates the occurrence and development of a variety of tumors, but there is no research regarding this gene in EC.

Methods

Based on The Cancer Genome Atlas (TCGA) database, we used a variety of bioinformatics tools and databases to explore the expression and prognosis of BTG1. We verified expression and prognosis of BTG1 in EC using qRT-PCR and analyzed the relevant clinicopathological parameters. We functionally enriched BTG1 and related genes in EC patients through the bioinformatics website and analyzed miRNA targets of BTG1 and interacting protein networks. Cell proliferation, wound healing, transwell invasion, and cell apoptosis assays were used to detect the effects of BTG1 on the malignant biological behavior of endometrial carcinoma cells (ECCs). The effect of BTG1 on the epithelial-to-mesenchymal transition (EMT) process was detected using western blot.

Results

We analyzed the expression and prognosis of BTG1 based on TCGA and found that low expression of BTG1 was associated with poor EC prognosis. The qRT-PCR suggested that BTG1 had low expression in EC. BTG1 expression was significantly correlated with overall survival (OS) shortening. Clinicopathological analysis suggested that expression of BTG1 was related to invasion depth and the International Federation of Gynecology and Obstetrics (FIGO) stage. EC pathological tissue type, fertility history, lymphatic metastasis, menopause, estrogen receptor (ER), progesterone receptor (PR), and age of diagnosis were not related. Functional enrichment analysis showed that BTG1 plays an important role in regulating embryonic development, tumorigenesis, apoptosis, and cell cycle. Biological behavior experiments suggest that BTG1 inhibits proliferation, migration, and invasion of ECCs, and promotes apoptosis of ECCs. Western blot indicated that BTG1 inhibited the EMT process of ECCs.

Conclusions

BTG1, as a tumor suppressor gene, plays an important role in the occurrence and development of EC. We believe that BTG1 can be used as a potential prognostic biomarker for EC.

The Role of Deferoxamine in Irradiated Breast Reconstruction: A Study of Oncologic Safety

BACKGROUND

Radiotherapy plays an essential role in the oncologic management of breast cancer. However, patients who undergo radiotherapy experience significantly more wound complications during the reconstructive process. Deferoxamine has immense potential to up-regulate angiogenesis and improve reconstructive outcomes. The purpose of this study was to determine the impact of deferoxamine on breast cancer cell proliferation in vitro, to delineate oncologic safety concerns regarding the use of deferoxamine as a regenerative therapeutic.

METHODS

The dose-dependent effect of radiation and deferoxamine on two triple-negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) was determined by means of MTS (percentage cell viability) and tumorsphere (sphere number) analysis. Radiation therapy and deferoxamine were delivered both individually and in combination, and all experiments were completed in triplicate. Intracellular iron, nuclear factor-κB localization, and apoptosis/necrosis assays were performed to delineate mechanism. Analysis of variance statistical analysis was performed using SPSS (p < 0.05).

RESULTS

For both cell lines, percentage viability and sphere number significantly decreased following exposure to 10 Gy of radiation. Surprisingly, the administration of 25 µM deferoxamine also significantly decreased each metric. The administration of deferoxamine (100 µM) in combination with radiation (10 Gy) resulted in significantly reduced percentage viability and sphere number compared with the administration of radiation alone. Deferoxamine treatment decreased intracellular iron, suppressed nuclear factor-κB activation, and induced apoptosis.

CONCLUSION

Radiation and deferoxamine significantly decrease breast cancer proliferation when delivered independently and in combination, suggesting deferoxamine may be safely used to facilitate improved reconstructive outcomes among triple-negative breast cancer survivors.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

microRNA-27a-3p Down-regulation Inhibits Malignant Biological Behaviors of Ovarian Cancer by Targeting BTG1

Ovarian cancer is the most deadly malignant tumor. MicroRNA-27a-3p (miR-27a-3p) was a tumor oncogene in various cancers. However, the role and mechanism of miR-27a-3p in ovarian cancer are still unknown. In this study, we found that miR-27a-3p over-expression could significantly promote the viability of SK-OV-3 cells, enhance cell migration and invasion, and reduce cell apoptosis. Besides, results from western blot assay showed that miR-27a-3p over-expression could increase Bcl-2 protein expression and decrease Bax protein expression. Furthermore, TargetScan and the dual luciferase reporter gene assay revealed that BTG anti-proliferation factor 1 (BTG1) was a direct target of miR-27a-3p. In addition, we found that miR-27a-3p down-regulation suppressed SK-OV-3 cell viability, migration and invasion, and promoted cell apoptosis. All the effects of miR-27a-3p down-regulation on SK-OV-3 cells were reversed by BTG1-siRNA. Therefore, miR-27a-3p/BTG1 axis may be a new potential target for the treatment of ovarian cancer.

MicroRNA-183 inhibition exerts suppressive effects on diabetic retinopathy by inactivating BTG1-mediated PI3K/Akt/VEGF signaling pathway

Diabetic retinopathy (DR) is a serious diabetic complication caused by both environmental and genetic factors. Molecular mechanisms of DR may lead to the discovery of reliable prognostic indicators. The current study aimed to clarify the mechanism of microRNA-183 (miR-183) in DR in relation to the PI3K/Akt/VEGF signaling pathway. Microarray-based gene expression profiling of DR was used to identify the differentially expressed genes. Sprague-Dawley rats were used for the establishment of DR models, and then miR-183 was altered by mimic or inhibitor or BTG1 was downregulated by siRNA to explore the regulatory mechanism of miR-183 in DR. Furthermore, the expression of miR-183, CD34, endothelial nitric oxide synthase (eNOS), BTG1 and the PI3K/Akt/VEGF signaling pathway-related genes as well as reactive oxygen species (ROS) level was determined, and the relationship between miR-183 and BTG1 was also verified. Cell growth, cell apoptosis, and angiogenesis were determined. Microarray analysis revealed the involvement of miR-183 in DR via the PI3K/Akt/VEGF signaling pathway by targeting BTG1. Upregulated miR-183 and downregulated BTG1 were observed in retinal tissues of DR rats. miR-183 overexpression activated the PI3K/Akt/VEGF signaling pathway, upregulated CD34, eNOS, and ROS, and inhibited BTG1. BTG1 was confirmed as a target gene of miR-183. miR-183 overexpression or BTG1 knockdown promoted cell growth and tube formation while it suppressed cell apoptosis of vascular endothelial cells in DR rats. In this study, we demonstrated that miR-183 silencing inhibiting cell growth and tube formation in vascular endothelial cells of DR rats via the PI3K/Akt/VEGF signaling pathway by upregulating BTG1.

Silencing the expression of MTDH increases the radiation sensitivity of SKOV3 ovarian cancer cells and reduces their proliferation and metastasis

Ovarian cancer has a high mortality rate among women worldwide. Radiotherapy is considered an effective method of ovarian cancer treatment, however, radioresistance presents a challenge. It is necessary to develop techniques that can increase radiosensitivity in ovarian cancer, and gene therapy is a promising option. The aim of the present study was to investigate the effects of metadherin (MTDH) silencing on the radiosensitivity of ovarian cancer. Ovarian cancer tissues (n=273) and normal ovarian tissues (n=277) were used, as were SKOV3 ovarian cancer cells and the immortalized human ovarian epidermal HOSEpiC cell line. MTT, Transwell and wound-healing assays were performed to assess the proliferation, invasion and migration abilities of the SKOV3 cells. Colony-forming assays and flow cytometry were applied to detect the radiosensitivity and apoptosis of the SKOV3 cells. Nude mouse xenograft models were established to evaluate the effect of MTDH gene silencing on tumor growth and the efficacy of radiotherapy. Ovarian cancer, in tissues and cells, was demonstrated to have a high level of MTDH. Additionally, MTDH silencing was found to significantly inhibit proliferation, migration and invasion, and induce apoptosis in SKOV3 cells, and it was suggested that MTDH depletion significantly increased the sensitivity of the SKOV3 cells to X-ray radiation. MTDH silencing enhanced radiosensitivity and delayed tumor growth in the nude mouse xenograft model. Collectively, the results obtained in the present study suggest the potential role of MTDH silencing as a technique for ameliorating radioresistance in ovarian cancer. The present study provides a promising experimental basis for the improvement of ovarian cancer radiotherapy treatment.

miR-511 promotes the proliferation of human hepatoma cells by targeting the 3'UTR of B cell translocation gene 1 (BTG1) mRNA

Aberrant expression of miR-511 is involved in the development of cancer, but the role of miR-511 in hepatocellular carcinoma (HCC) is not well documented. In this study, we explored the molecular mechanisms of miR-511 in hepatocarcinogenesis. Our results of bioinformatics analysis suggested that B cell translocation gene 1 (BTG1), a member of anti-proliferative gene family, was one of the putative targets of miR-511. The expression levels of miR-511 were significantly higher in 30 clinical HCC tissues than in corresponding peritumor tissues, and were negatively correlated with those of BTG1 in the HCC tissues (r=-0.6105, P<0.01). In human hepatoma cell lines HepG2 and H7402, overexpression of miR-511 dose-dependently inhibited the expression of BTG1, whereas knockdown of miR-511 dose-dependently increased the expression of BTG1. Luciferase reporter gene assays verified that miR-511 targeted the 3'UTR of BTG1 mRNA. In the hepatoma cells, overexpression of miR-511 significantly decreased BTG1-induced G₁ phase arrest, which was rescued by overexpression of BTG1. Furthermore, overexpression of miR-511 promoted the proliferation of the hepatoma cells, which was rescued by overexpression of BTG1. Conversely, knockdown of miR-511 inhibited cell proliferation, which was reversed by knockdown of BTG1. In conclusion, miR-511 promotes the proliferation of human hepatoma cells in vitro by targeting the 3'UTR of BTG1 mRNA.