BACH1 promotes the progression of human colorectal cancer through BACH1/CXCR4 pathway

Peritoneal infection after colorectal cancer surgery induces substantial alterations in postoperative protein levels: an exploratory study

PURPOSE

Peritoneal infection, due to anastomotic leakage, after resection for colorectal cancer have been shown to associate with increased cancer recurrence and mortality, as well as cardiovascsular morbidity. Alterations in circulating protein levels could help shed light on the underlying mechanisms, prompting this exploratory study of 64 patients operated for colorectal cancer with anastomosis.

METHODS

Thirty-two cases who suffered a postoperative peritoneal infection were matched with 32 controls who had a complication-free postoperative stay. Proteins in serum samples at their first postoperative visit and at one year after surgery were analysed using proximity extension assays and enzyme-linked immunosorbent assays. Multivariate projection methods, adjusted for multiple testing, were used to compare levels between groups, and enrichment and network analyses were performed.

RESULTS

Seventy-seven proteins, out of 270 tested, were differentially expressed at a median sampling time of 41 days postoperatively. These proteins were all normalised one year after surgery. Many of the differentially expressed top hub proteins have known involvement in cancer progression, survival, invasiveness and metastasis. Over-represented pathways were related to cardiomyopathy, cell-adhesion, extracellular matrix, phosphatidylinositol-3-kinase/Akt (PI3K-Akt) and transforming growth factor beta (TGF-β) signaling.

CONCLUSION

These affected proteins and pathways could provide clues as to why patients with peritoneal infection might suffer increased cancer recurrence, mortality and cardiovascular morbidity.

Transcription factor BACH1 in cancer: roles, mechanisms, and prospects for targeted therapy

Transcription factor BTB domain and CNC homology 1 (BACH1) belongs to the Cap 'n' Collar and basic region Leucine Zipper (CNC-bZIP) family. BACH1 is widely expressed in mammalian tissues, where it regulates epigenetic modifications, heme homeostasis, and oxidative stress. Additionally, it is involved in immune system development. More importantly, BACH1 is highly expressed in and plays a key role in numerous malignant tumors, affecting cellular metabolism, tumor invasion and metastasis, proliferation, different cell death pathways, drug resistance, and the tumor microenvironment. However, few articles systematically summarized the roles of BACH1 in cancer. This review aims to highlight the research status of BACH1 in malignant tumor behaviors, and summarize its role in immune regulation in cancer. Moreover, this review focuses on the potential of BACH1 as a novel therapeutic target and prognostic biomarker. Notably, the mechanisms underlying the roles of BACH1 in ferroptosis, oxidative stress and tumor microenvironment remain to be explored. BACH1 has a dual impact on cancer, which affects the accuracy and efficiency of targeted drug delivery. Finally, the promising directions of future BACH1 research are prospected. A systematical and clear understanding of BACH1 would undoubtedly take us one step closer to facilitating its translation from basic research into the clinic.

BACH1 Loss Exerts Antitumor Effects on Mantle Cell Lymphoma Cells via Inducing a Tumor-Intrinsic Innate Immune Response and Cell-Cycle Arrest

BTB and CNC homology 1 (BACH1) is a transcription repressor that regulates multiple physiological processes, including intracellular heme homeostasis and immune responses. Increasing lines of evidence indicate that BACH1 reshapes metastasis and metabolism of human solid tumors. However, its potential roles in mantle cell lymphoma (MCL) remain largely unknown. Here, we found that silencing BACH1 in MCL cells induced markedly cell-cycle arrest and cell apoptosis, whereas overexpression of BACH1 exhibited the opposite patterns. Increased BACH1 levels not only promoted tumor growth and dispersal in xenografts, but also conferred a long-term poor prognosis in patients with MCL. Interestingly, RNA sequencing analysis revealed noncanonical function of BACH1 in regulation of type I interferon (IFNI) response, DNA replication and repair, and cell cycle. Mechanistically, zinc finger and BTB domain containing 20 (ZBTB20) and HMG-box transcription factor 1 (HBP1) were for the first time identified as two novel downstream targets repressed by BACH1 in MCL cells. Further double-knockdown functional assays confirmed that loss of BACH1 induced ZBTB20-mediated IFNα production and HBP1-mediated cell-cycle arrest, indicating that BACH1-centered regulatory network may be a novel targetable vulnerability in MCL cells.

IMPLICATIONS

BACH1 serves as a pleotropic regulator of tumor-intrinsic innate immune response and cell-cycle progression, disruption of which may offer a promising therapeutic strategy for MCL treatment.

A systems-level analysis of the mutually antagonistic roles of RKIP and BACH1 in dynamics of cancer cell plasticity

Epithelial-mesenchymal transition (EMT) is an important axis of phenotypic plasticity-a hallmark of cancer metastasis. Raf kinase-B inhibitor protein (RKIP) and BTB and CNC homology 1 (BACH1) are reported to influence EMT. In breast cancer, they act antagonistically, but the exact nature of their roles in mediating EMT and associated other axes of plasticity remains unclear. Here, analysing transcriptomic data, we reveal their antagonistic trends in a pan-cancer manner in terms of association with EMT, metabolic reprogramming and immune evasion via PD-L1. Next, we developed and simulated a mechanism-based gene regulatory network that captures how RKIP and BACH1 engage in feedback loops with drivers of EMT and stemness. We found that RKIP and BACH1 belong to two antagonistic 'teams' of players-while BACH1 belonged to the one driving pro-EMT, stem-like and therapy-resistant cell states, RKIP belonged to the one enabling pro-epithelial, less stem-like and therapy-sensitive phenotypes. Finally, we observed that low RKIP levels and upregulated BACH1 levels associated with worse clinical outcomes in many cancer types. Together, our systems-level analysis indicates that the emergent dynamics of underlying regulatory network enable the antagonistic patterns of RKIP and BACH1 with various axes of cancer cell plasticity, and with patient survival data.

BACH1 promotes lung adenocarcinoma cell metastasis through transcriptional activation of ITGA2

BACH1 plays an important role in promoting cancer. This study aims to further verify the relationship between the expression level of BACH1 in lung adenocarcinoma prognosis, as well as the influence of BACH1 expression on lung adenocarcinoma and the potential mechanism. The expression level of BACH1 in lung adenocarcinoma and its relationship with prognosis was evaluated by lung adenocarcinoma tissue microarray analysis combined with bioinformatics approaches. Gene knockdown and overexpression were used to investigate the functions and molecular mechanisms of BACH1 in lung adenocarcinoma cells. The regulatory downstream pathways and target genes of BACH1 in lung adenocarcinoma cells were explored by bioinformatics and RNA sequencing data analysis, real-time PCR, western blot analysis, and cell immunofluorescence and cell adhesion assays. Chromatin immunoprecipitation and dual-luciferase reporter assays were carried out to verify the target gene binding site. In the present study, BACH1 is abnormally highly expressed in lung adenocarcinoma tissues, and high BACH1 expression is negatively correlated with patient prognosis. BACH1 promotes the migration and invasion of lung adenocarcinoma cells. Mechanistically, BACH1 directly binds to the upstream sequence of the ITGA2 promoter to promote ITGA2 expression, and the BACH1-ITGA2 axis is involved in cytoskeletal regulation in lung adenocarcinoma cells by activating the FAK-RAC1-PAK signaling pathway. Our results indicated that BACH1 positively regulates the expression of ITGA2 through a transcriptional mechanism, thereby activating the FAK-RAC1-PAK signaling pathway to participate in the formation of the cytoskeleton in tumor cells and then promoting the migration and invasion of tumor cells.

USP14 regulates heme metabolism and ovarian cancer invasion through BACH1 deubiquitination and stabilization

The deubiquitinating enzyme USP14 has been established as a crucial regulator in various diseases, including tumors, neurodegenerative diseases, and metabolic diseases, through its ability to stabilize its substrate proteins. Our group has utilized proteomic techniques to identify new potential substrate proteins for USP14, however, the underlying signaling pathways regulated by USP14 remain largely unknown. Here, we demonstrate the key role of USP14 in both heme metabolism and tumor invasion by stabilizing the protein BACH1. The cellular oxidative stress response factor NRF2 regulates antioxidant protein expression through binding to the antioxidant response element (ARE). BACH1 can compete with NRF2 for ARE binding, leading to the inhibition of the expression of antioxidant genes, including HMOX-1. Activated NRF2 also inhibits the degradation of BACH1, promoting cancer cell invasion and metastasis. Our findings showed a positive correlation between USP14 expression and NRF2 expression in various cancer tissues from the TCGA database and normal tissues from the GTEx database. Furthermore, activated NRF2 was found to increase USP14 expression in ovarian cancer (OV) cells. The overexpression of USP14 was observed to inhibit HMOX1 expression, while USP14 knockdown had the opposite effect, suggesting a role for USP14 in regulating heme metabolism. The depletion of BACH1 or inhibition of heme oxygenase 1 (coded by HMOX-1) was also found to significantly impair USP14-dependent OV cell invasion. In conclusion, our results highlight the importance of the NRF2-USP14-BACH1 axis in regulating OV cell invasion and heme metabolism, providing evidence for its potential as a therapeutic target in related diseases.

Pathophysiological role of BACH transcription factors in digestive system diseases

BTB and CNC homologous (BACH) proteins, including BACH1 and BACH2, are transcription factors that are widely expressed in human tissues. BACH proteins form heterodimers with small musculoaponeurotic fibrosarcoma (MAF) proteins to suppress the transcription of target genes. Furthermore, BACH1 promotes the transcription of target genes. BACH proteins regulate physiological processes, such as the differentiation of B cells and T cells, mitochondrial function, and heme homeostasis as well as pathogenesis related to inflammation, oxidative-stress damage caused by drugs, toxicants, or infections; autoimmunity disorders; and cancer angiogenesis, epithelial-mesenchymal transition, chemotherapy resistance, progression, and metabolism. In this review, we discuss the function of BACH proteins in the digestive system, including the liver, gallbladder, esophagus, stomach, small and large intestines, and pancreas. BACH proteins directly target genes or indirectly regulate downstream molecules to promote or inhibit biological phenomena such as inflammation, tumor angiogenesis, and epithelial-mesenchymal transition. BACH proteins are also regulated by proteins, miRNAs, LncRNAs, labile iron, and positive and negative feedback. Additionally, we summarize a list of regulators targeting these proteins. Our review provides a reference for future studies on targeted drugs in digestive diseases.

BACH1-induced ferroptosis drives lymphatic metastasis by repressing the biosynthesis of monounsaturated fatty acids

Esophageal squamous cell carcinoma (ESCC) is one of the fatal malignancies worldwide. It has an increased propensity to metastasize via lymphogenous routes in an early stage. The prognosis of patients with lymph node metastases (LNM) is often worse than that of patients without metastases. Although several factors have been found to influence metastasis, the mechanisms of preference for specific metastatic routes remain poorly understood. Herein, we provide evidence that the intrinsic hypersensitivity of tumor cells to ferroptosis may proactively drive lymphatic metastasis. Serum autoantibodies associated with LNM of early ESCC were screened using a whole-proteome protein array containing 19 394 human recombinant proteins, and an anti-BACH1 autoantibody was first identified. Pan-cancer analysis of ferroptosis-related genes with preferential lymphatic metastasis and preferential hematogenous metastasis based on The Cancer Genome Atlas data was performed. Only BACH1 showed significant overexpression in tumors with preferential lymphatic metastasis, whereas it was downregulated in most tumors with preferential nonlymphatic metastasis. In addition, it was found that the serum levels of autoantibodies against BACH1 were elevated in early-stage patients with LNM. Interestingly, BACH1 overexpression and ferroptosis induction promoted LNM but inhibited hematogenous metastasis in mouse models. Transcriptomic and lipidomic analyses found that BACH1 repressed SCD1-mediated biosynthesis of monounsaturated fatty acids, especially oleic acid (OA). OA significantly attenuated the ferroptotic phenotypes and reversed the metastatic properties of BACH1-overexpressing cells. OA addition significantly rescued the ferroptotic phenotypes and reversed the metastatic properties of BACH1-overexpressing cells. Importantly, the concentration gradient of OA between primary lesions and the lymph resulted in the chemoattraction of tumor cells to promote invasion, thus facilitating lymphatic metastasis. BACH1-induced ferroptosis drives lymphatic metastasis via the BACH1-SCD1-OA axis. More importantly, this study confirms that ferroptosis is a double-edged sword in tumorigenesis and tumor progression. The clinical application of ferroptosis-associated agents requires a great caution.

BACH1 promotes clear cell renal cell carcinoma progression by upregulating oxidative stress-related tumorigenicity

The carcinogenesis and progression of renal cell carcinoma (RCC), a heterogeneous cancer derived from renal tubular epithelial cells, is closely related to oxidative stress responses (OSRs). Oxidative stress responses participate in various biological processes related to the metabolism and metastatic potential of cancer such as inflammation, epithelial-mesenchymal transition (EMT), and angiogenesis. In this study, we investigated the role of broad complex-tramtrack-bric-a-brac and cap 'n' collar homology 1 (BACH1), a key transcription factor for OSRs, in clear cell RCC (ccRCC) development and prognosis. The poor prognosis and elevation of serum inflammation markers in nephrectomized ccRCC patients were correlated with the intratumor expression of BACH1 accompanied by a downregulation of heme oxygenase-1. BACH1 contributes to the invasion and migration abilities of RCC cell lines without affecting their proliferation in vitro. In contrast, BACH1 contributes to tumor progression in vivo, in relation to OSRs with the activation of EMT-related pathways. BACH1 involvement in other OSR-linked pathways, including inflammatory responses, angiogenesis, and mTOR signaling, was further revealed by RNA sequencing analysis of BACH1-knockdown cells. In conclusion, the crucial role of BACH1 in the pathogenesis and poor prognosis of ccRCC through the promotion of OSRs is suggested.

BTB domain and CNC homolog 1 promotes glioma invasion mainly through regulating extracellular matrix and increases ferroptosis sensitivity

BTB Domain and CNC Homolog 1 (Bach1) has been implicated in cancer progression, particularly in invasion, but little is unknown about its effect on glioma. Here, we confirmed that highly expressed Bach1 prominently promoted glioma invasion. Similar to the reported mechanisms in other tumors, Bach1 upregulation was also correlated with epithelial mesenchymal transition (EMT) in glioma cells. More importantly, proteomic analysis indicated that the main mechanism of Bach1 promoting invasion in glioma involved extracellular matrix (ECM). We further found thatBach1 upregulation was associated with the multiple mechanisms of ECM remodeling in glioma, including increasing the expression and deposition of ECM components, activating TGFBR2-smad2/3 signaling, promoting invadopodia formation and inducing the expression and secretion of MMP2. Meanwhile, Bach1 overexpression increased ferroptosis sensitivity in glioma cells. The ferroptosis inducer (sulfasalazine) obviously suppressed the gliomas with Bach1 upregulation in vitro and in vivo. Overall, Bach1 has a two-faced role in glioma. Highly expressed Bach1 promotes glioma invasion. Conversely, Bach1 upregulation is also a potential indicator of the sensitivity of ferroptosis inducers.

The mitotic regulator RCC2 promotes glucose metabolism through BACH1-dependent transcriptional upregulation of hexokinase II in glioma

Weighted gene co-expression network analysis (WGCNA) identified a cell-cycle module that is associated with poor prognosis and aggressiveness of glioma. One of the core members, Regulator of chromatin condensation 2 (RCC2) is a component of the chromosome passenger complex. Accumulating evidence suggests that RCC2 plays a vital role in the mitotic process and that abnormal RCC2 expression is involved in cancer development. Gene silencing experiments show that RCC2 is required for glioma cell proliferation and migration. RNA-Sequencing analysis reveals a dual role of RCC2 in both the cell cycle and metabolism. Specifically, RCC2 regulates G2/M progression via CDC2 phosphorylation at Tyrosine 15. Metabolomic analysis identifies a role for RCC2 in promoting the glycolysis and pentose phosphate pathway. RCC2 exerts effects on metabolism by stabilizing the transcription factor BACH1 at its C-terminus leading to the transcriptional upregulation of hexokinase 2 (HK2). These findings elucidate a novel PTEN/RCC2/BACH1/HK2 signaling axis that drives glioma progression through the dual regulation of mitotic cell cycle and glycolytic events.

The role of miR-4469 as a tumor suppressor regulating inflammatory cell infiltration in colorectal cancer

Background

MicroRNA (miRNA) regulates gene expression posttranscriptionally, and some of them function in tumor suppression and can be used in drug development. As a result, identifying and screening miRNAs that suppress tumors would be a significant addition to tumor treatment.

Methods

In this study, we analyzed the miRNA expression profile of colorectal cancer (CRC), constructed a negative regulatory network of the miRNA-target genes, and identified miR-4469 as one of the key tumor suppressors miRNAs. We analyzed the expression and survival of miR-4469 in pan-cancer, experimentally verified the expression level of miR-4469 in CRC cells and the effect on CRC cell proliferation and migration. We screened miR-4469 target genes for enrichment analysis and immune cell infiltration analysis and validated target gene expression to clarify the regulatory mechanisms involved in miR-4469.

Results

miR-4469 was more highly expressed in normal colorectum tissues compared to CRC tissues and correlated with survival time in patients with multiple cancers. It was shown that miR-4469 was highly expressed in normal colon cells and miR-4469 expression could inhibit the proliferation and migration of CRC cells. In addition, studies on the mechanism showed that miR-4469 function is mainly related to the regulation of inflammatory cell infiltration, and the key target genes of miR-4469 in this process are SLC2A3, FGR, PLEKHO2, and MYO1F.

Conclusion

miR-4469 is a tumor suppressor in CRC, and its regulatory mechanism mainly affects the infiltration of inflammatory cells in the cancer tissue.

The diversity of heme sensor systems - heme-responsive transcriptional regulation mediated by transient heme protein interactions

Heme is a versatile molecule that is vital for nearly all cellular life by serving as prosthetic group for various enzymes or as nutritional iron source for diverse microbial species. However, elevated levels of heme molecule are toxic to cells. The complexity of this stimulus has shaped the evolution of diverse heme sensor systems, which are involved in heme-dependent transcriptional regulation in eukaryotes and prokaryotes. The functions of these systems are manifold - ranging from the specific control of heme detoxification or uptake systems to the global integration of heme and iron homeostasis. This review focuses on heme sensor systems, regulating heme homeostasis by transient heme protein interaction. We provide an overview of known heme-binding motifs in prokaryotic and eukaryotic transcription factors. Besides the central ligands, the surrounding amino acid environment was shown to play a pivotal role in heme binding. The diversity of heme-regulatory systems therefore illustrates that prediction based on pure sequence information is hardly possible and requires careful experimental validation. Comprehensive understanding of heme-regulated processes is not only important for our understanding of cellular physiology, but also provides a basis for the development of novel antibacterial drugs and metabolic engineering strategies.

Iron in Cancer Progression: Does BACH1 Promote Metastasis by Altering Iron Homeostasis?

The transcription factor BACH1, which is regulated by direct binding of prosthetic group heme, promotes epithelial-mesenchymal transition (EMT) and drives metastasis of diverse types of cancer cells. De-regulated target genes of BACH1 in cancer cells include those for glycolysis, oxidative phosphorylation, epithelial cell adhesion, and mesodermal cell motility. In addition, the canonical target genes of BACH1 include genes for the regulation of iron homeostasis. Importantly, cancer cells are addicted to iron. We summarize known functions of BACH1 in cancer and discuss how BACH1 may affect iron homeostasis in cancer cells to support their progression by increasing mobile iron within cells. The dependency on BACH1 for cancer progression may also confer upon cancer cells susceptibility to iron-dependent cell death ferroptosis. Finally, we discuss that the human transcription factors provide research opportunities for better understanding of cancer cell properties.

BACH1, the master regulator of oxidative stress, has a dual effect on CFTR expression

The cystic fibrosis transmembrane conductance regulator (CFTR) gene lies within a topologically associated domain (TAD) in which multiple cis-regulatory elements (CREs) and transcription factors (TFs) regulate its cell-specific expression. The CREs are recruited to the gene promoter by a looping mechanism that depends upon both architectural proteins and specific TFs. An siRNA screen to identify TFs coordinating CFTR expression in airway epithelial cells suggested an activating role for BTB domain and CNC homolog 1 (BACH1). BACH1 is a ubiquitous master regulator of the cellular response to oxidative stress. Here, we show that BACH1 may have a dual effect on CFTR expression by direct occupancy of CREs at physiological oxygen (∼8%), while indirectly modulating expression under conditions of oxidative stress. Hence BACH1, can activate or repress the same gene, to fine tune expression in response to environmental cues such as cell stress. Furthermore, our 4C-seq data suggest that BACH1 can also directly regulate CFTR gene expression by modulating locus architecture through occupancy at known enhancers and structural elements, and depletion of BACH1 alters the higher order chromatin structure.

Regulatory mechanisms of heme regulatory protein BACH1: a potential therapeutic target for cancer

A limited number of overexpressed transcription factors are associated with cancer progression in many types of cancer. BTB and CNC homology 1 (BACH1) is the first mammalian heme-binding transcription factor that belongs to the basic region leucine zipper (bZIP) family and a member of CNC (cap 'n' collar). It forms heterodimers with the small musculoaponeurotic fibrosarcoma (MAF) proteins and stimulates or suppresses the expression of target genes under a very low intracellular heme concentration. It possesses a significant regulatory role in heme homeostasis, oxidative stress, cell cycle, apoptosis, angiogenesis, and cancer metastasis progression. This review discusses the current knowledge about how BACH1 regulates cancer metastasis in various types of cancer and other carcinogenic associated factors such as oxidative stress, cell cycle regulation, apoptosis, and angiogenesis. Overall, from the reported studies and outcomes, it could be realized that BACH1 is a potential pharmacological target for discovering new therapeutic anticancer drugs.

Circ_0087862 promotes the progression of colorectal cancer by sponging miR-142-3p and up-regulating BACH1 expression

Circular RNAs (circRNAs) feature prominently in regulating the malignant biological behaviors of colorectal cancer (CRC), including cell viability, cell cycle progression, apoptosis, migration, invasion, and so on. This study is performed to probe into the biological function and molecular mechanism of circ_0087862 in CRC. The expression profile of GSE138589 was available from Gene Expression Omnibus (GEO), and the differentially expressed circRNAs were analyzed by GEO2R. The expression of circ_0087862, miR-142-3p, and BACH1 mRNA in CRC tissues and cells was measured by qRT-PCR. CCK-8 assay was employed to determine the proliferation of CRC cells. Scratch wound healing and transwell assays were used to examine the migration and invasion of CRC cells. The targeting relationships between circ_0087862 and miR-142-3p, and between miR-142-3p and BACH1 3'UTR were verified by dual-luciferase reporter gene assay and RIP assay. BACH1 protein expression was probed by western blot. Circ_0087862 was highly expressed in CRC tissues and cell lines. Knocking down circ_0087862 significantly restrained the multiplication, migration and invasion of CRC cells. miR-142-3p inhibition weakened the impact of circ_0087862 knockdown on CRC cells. Circ_0087862 regulated BACH1 expressions by targeting miR-142-3p. Circ_0087862 regulates BACH1 expressions through sponging miR-142-3p, and promotes the proliferation, migration, and invasion of CRC cells.

The transcription factor BACH1 at the crossroads of cancer biology: From epithelial-mesenchymal transition to ferroptosis

The progression of cancer involves not only the gradual evolution of cells by mutations in DNA but also alterations in the gene expression induced by those mutations and input from the surrounding microenvironment. Such alterations contribute to cancer cells' abilities to reprogram metabolic pathways and undergo epithelial-to-mesenchymal transition (EMT), which facilitate the survival of cancer cells and their metastasis to other organs. Recently, BTB and CNC homology 1 (BACH1), a heme-regulated transcription factor that represses genes involved in iron and heme metabolism in normal cells, was shown to shape the metabolism and metastatic potential of cancer cells. The growing list of BACH1 target genes in cancer cells reveals that BACH1 promotes metastasis by regulating various sets of genes beyond iron metabolism. BACH1 represses the expression of genes that mediate cell–cell adhesion and oxidative phosphorylation but activates the expression of genes required for glycolysis, cell motility, and matrix protein degradation. Furthermore, BACH1 represses FOXA1 gene encoding an activator of epithelial genes and activates SNAI2 encoding a repressor of epithelial genes, forming a feedforward loop of EMT. By synthesizing these observations, we propose a “two-faced BACH1 model”, which accounts for the dynamic switching between metastasis and stress resistance along with cancer progression. We discuss here the possibility that BACH1-mediated promotion of cancer also brings increased sensitivity to iron-dependent cell death (ferroptosis) through crosstalk of BACH1 target genes, imposing programmed vulnerability upon cancer cells. We also discuss the future directions of this field, including the dynamics and plasticity of EMT.

Genome-wide CRISPR/Cas9 screening identifies CARHSP1 responsible for radiation resistance in glioblastoma

Glioblastomas (GBM) is the most common primary malignant brain tumor, and radiotherapy plays a critical role in its therapeutic management. Unfortunately, the development of radioresistance is universal. Here, we identified calcium-regulated heat-stable protein 1 (CARHSP1) as a critical driver for radioresistance utilizing genome-wide CRISPR activation screening. This is a protein with a cold-shock domain (CSD)-containing that is highly similar to cold-shock proteins. CARHSP1 mRNA level was upregulated in irradiation-resistant GBM cells and knockdown of CARHSP1 sensitized GBM cells to radiotherapy. The high expression of CARHSP1 upon radiation might mediate radioresistance by activating the inflammatory signaling pathway. More importantly, patients with high levels of CARHSP1 had poorer survival when treated with radiotherapy. Collectively, our findings suggested that targeting the CARHSP1/TNF-α inflammatory signaling activation induced by radiotherapy might directly affect radioresistance and present an attractive therapeutic target for GBM, particularly for patients with high levels of CARHSP1.

BACH1 promotes the progression of esophageal squamous cell carcinoma by inducing the epithelial-mesenchymal transition and angiogenesis

Metastasis to regional lymph nodes or distal organs predicts the progression of the disease and poor prognosis in esophageal squamous cell carcinoma (ESCC). Previous studies demonstrated that BTB and CNC homology 1 (BACH1) participates in various types of tumor metastasis. However, the function of BACH1 in ESCC was rarely reported. The present study demonstrated that BACH1 protein was overexpressed in ESCC tissues compared with paired esophageal epithelial tissues according to immunohistochemical staining (IHC). Higher levels of BACH1 mRNA were associated with decreased overall survival (OS) and shorter disease‐free survival (DFS) of ESCC patients based on an analysis of The Cancer Genome Atlas (TCGA) datasets. BACH1 significantly enhanced the migration and invasion of ESCC in vitro. Mechanistically, BACH1 promoted the epithelial–mesenchymal transition (EMT) by directly activating the transcription of CDH2, SNAI2, and VIM, as determined by chromatin immunoprecipitation‐quantitative polymerase chain reaction (ChIP‐qPCR). BACH1 overexpression significantly enhanced CDH2 promoter activity according to the results of a luciferase assay. The results of subsequent experiments indicated that BACH1 enhanced the growth of tumor xenografts. The density of CD31⁺ blood vessels and the expression of vascular endothelial growth factor C (VEGFC) in tumor xenografts were significantly associated with BACH1 levels according to the results of IHC and immunofluorescence (IF) analyses performed in vivo. Moreover, ChIP‐qPCR analysis demonstrated that the transcriptional activity of VEGFC was also upregulated by BACH1. Thus, BACH1 contributes to ESCC metastasis and tumorigenesis by partially facilitating the EMT and angiogenesis, and BACH1 may be a promising therapeutic target or molecular marker in ESCC.

BACH1 is transcriptionally inhibited by TET1 in hepatocellular carcinoma in a microRNA-34a-dependent manner to regulate autophagy and inflammation

Hepatocellular carcinoma (HCC), one of the main contributors to cancer-associated deaths globally, is characterized by high invasiveness. Herein, we studied the molecular mechanisms underlying ten-eleven translocation 1 (TET1)-mediated autophagy in HCC. Following data mining using GSE101728, GSE14520 and GSE138178, TET1 was screened out, and the differential expression of TET1 was verified by bioinformatics analysis. TET1, one of the prognostic markers in HCC, was poorly expressed in HCC. Through functional experiments, we determined that upregulation of TET1 inhibited the proliferation, migration, invasion, tumorigenesis, metastasis and inflammatory factors of HCC cells, and promoted cell autophagy and apoptosis. Mechanistically, TET1 activated miR-34a by demethylating miR-34a. BTB domain and CNC homology 1 (BACH1) was identified as the target gene of miR-34a. Notably, Downregulation of miR-34a increased cellular inflammatory factors and decreased autophagy in the presence of TET1, while declines in BACH1 suppressed cellular inflammatory factors and enhanced autophagy in the presence of miR-34a inhibitor. BACH1 negatively regulated the p53 pathway. In conclusion, TET1 is a tumor suppressor in the progression of HCC by regulating the miR-34a/BACH1/p53 axis, and may contribute to the improvement of HCC prognosis and therapy.

Circular RNA circ_0000337 contributes to osteosarcoma via the miR-4458/BACH1 pathway

BACKGROUND

As the most prevalent primary bone malignancy in children and adolescents, osteosarcoma (OS) has attracted increasing attention. The role of circRNAs in OS has been elucidated in some reports, but many circRNAs remain unexplored. Circ_0000337 has only been revealed as an oncogenic circRNA in esophageal squamous cell carcinoma. Yet whether circ_0000337 exerts any specific function in OS has not been unmasked.

METHODS

RT-qPCR was used for measurement of circ_0000337, miR-4458 and BACH1 mRNA levels. Western blot was conducted to detect BACH1 protein. CCK-8 assay, Casepase-3 activity assay and transwell assay were utilized to assess changes on cellular processes. Cytoplasmic/nuclear fractionation assay was conducted for circ_0000337 localization in OS cells. Luciferase reporter assay and RIP assay were performed to validate the interaction between miR-4458 and circ_0000337 or BACH1.

RESULTS

Circ_0000337 expression was upregulated in OS cell lines and it silence hindered OS cell proliferation and migration. MiR-4458 was downregulated in OS cells and miR-4458 upregulation suppressed OS cell growth and migration. Importantly, circ_0000337 sponged miR-4458 to elevate BACH1 expression, thus facilitating OS development.

CONCLUSIONS

This research for the first time documented that circ_0000337 promoted OS progression via sponging miR-4458 and thus elevating BACH1 expression, offering rational therapeutic target for OS.

Identification of a 14-Gene Prognostic Signature for Diffuse Large B Cell Lymphoma (DLBCL)

Although immunotherapy is a potential strategy to resist cancers, due to the inadequate acknowledge, this treatment is not always effective for diffuse large B cell lymphoma (DLBCL) patients. Based on the current situation, it is critical to systematically investigate the immune pattern. According to the result of univariate and multivariate cox proportional hazards, LASSO regression and Kaplan-Meier survival analysis on immune-related genes (IRGs), a prognostic signature, containing 14 IRGs (AQP9, LMBR1L, FGF20, TANK, CRP, ORM1, JAK1, BACH2, MTCP1, IFITM1, TNFSF10, FGF12, RFX5, and LAP3), was built. This model was validated by external data, and performed well. DLBCL patients were divided into low- and high-risk groups, according to risk scores from risk formula. The results of CIBERSORT showed that different immune status and infiltration pattern were observed in these two groups. Gene set enrichment analysis (GSEA) indicated 12 signaling pathways were significantly enriched in the high-risk group, such as natural killer cell-mediated cytotoxicity, toll-like receptor signaling pathway, and so on. In summary, 14 clinically significant IRGs were screened to build a risk score formula. This formula was an accurate tool to provide a certain basis for the treatment of DLBCL patients.

LncRNA TRG-AS1 stimulates hepatocellular carcinoma progression by sponging miR-4500 to modulate BACH1

Background

T cell receptor gamma locus antisense RNA 1 (TRG-AS1) has been reported to involve in the progression of glioblastoma, however the role and its underlying molecular mechanism in hepatocellular carcinoma (HCC) remain unknown.

Methods

Quantitative real-time polymerase chain reaction (RT-qPCR) was applied to detect TRG-AS1 expression in HCC cells. Besides, the proliferation abilities of HCC cells were assessed by colony formation and EdU assays. The migratory and invasive abilities of HCC cells were examined by transwell assays. Imunofluorescence staining (IF) was used to analyze the epithelial–mesenchymal transitions (EMT). The interaction among TRG-AS1, miR-4500 and BTB domain and CNC homolog 1 (BACH1) were proofed by means of RIP and RNA pull down and luciferase reporter assays.

Results

TRG-AS1 was conspicuously overexpressed in HCC cells. TRG-AS1 silencing apparently suppressed HCC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT). Mechanism exploration revealed that TRG-AS1 acted as a molecular sponge of miR-4500 to regulate BACH1. MiR-4500 silencing or BACH1 overexpression in BACH1-downregulated cells fully rescued cell proliferation migration, invasion and EMT progress.

Conclusion

TRG-AS1 regulates HCC progression by targeting miR-4500/BACH1 axis.

Linc01194 acts as an oncogene in colorectal carcinoma and is associated with poor survival outcome

Background

The incidence of colorectal cancer ranks among the top three malignant tumors, attributing to more than 50,000 deaths in the United States every year. Survival rate is directly correlated with TNM stage at diagnosis, and identifying the molecules involved in the cancer development process will provide directions to better investigate the mechanisms of colorectal cancer.

Materials and methods

Bioinformatics analysis of differentially expressed long noncoding RNAs (lncRNAs), survival analysis, cell proliferation assay, migration assay, and Western blot analysis were performed.

Results

Fifty-one lncRNAs were identified between the early stage and late-stage groups. In the survival analysis, we found that Linc01194 is correlated with poor survival of colon cancer patients. In addition, by suppressing the expression of Linc01194 in colon cancer cell lines, cell proliferation and migration were inhibited. Western blot showed that N-cadherin and vimentin were downregulated, whereas E-cadherin was upregulated indicating that the process of epithelial–mesenchymal transition (EMT) was restrained.

Conclusion

Linc01194 promotes the proliferation and migration ability of colon cancer cells by activating EMT. It acts as an oncogene in colorectal carcinoma and is associated with worse survival outcome.

Nuclear factor erythroid 2-related factors 1 and 2 are able to define the worst prognosis group among high-risk diffuse large B cell lymphomas treated with R-CHOEP

AIMS

Oxidative stress markers and antioxidant enzymes have previously been shown to have prognostic value and associate with adverse outcome in patients with diffuse large B cell lymphoma (DLBCL). Nuclear factor erythroid 2-related factor 1 (Nrf1) and factor 2 (Nrf2) are among the principal inducers of antioxidant enzyme production. Kelch ECH associating protein 1 (Keap1) is a negative regulator of Nrf2, and BTB (BR-C, ttk and bab) domain and CNC homolog 1 (Bach1) represses the function of both factors. Their significance in DLBCL prognosis is unknown.

METHODS

Diagnostic biopsy samples of 76 patients with high-risk DLBCL were retrospectively stained with immunohistochemistry for Nrf1, Nrf2, Keap1 and Bach1, and correlated with clinical data and outcome.

RESULTS

Nuclear Nrf2 and nuclear Bach1 expression were associated with adverse clinical features (anaemia, advanced stage, high IPI, high risk of neutropaenic infections), whereas cytoplasmic Nrf1 and Nrf2 were associated with favourable clinical presentation (normal haemoglobin level, no B symptoms, limited stage). None of the evaluated factors could predict survival alone. However, when two of the following parameters were combined: high nuclear score of Nrf2, low nuclear score of Nrf1, high cytoplasmic score of Nrf1 and low cytoplasmic score of Keap1 were associated with significantly worse overall survival.

CONCLUSIONS

Nrf1 and Nrf2 are relevant in disease presentation and overall survival in high-risk DLBCL. Low nuclear expression of Nrf1, high cytoplasmic expression of Nrf1, high nuclear expression of Nrf2 and low cytoplasmic expression of Keap1 are associated with adverse outcome in this patient group.

BTB and CNC homology 1 (Bach1) promotes human ovarian cancer cell metastasis by HMGA2-mediated epithelial-mesenchymal transition

Transcriptional factor BTB and CNC homology 1 (Bach1) has been linked to tumor progression and metastasis, but the mechanisms underlying the effects of Bach1 on tumor growth and metastasis are largely uncharacterized. Here, we report that Bach1 expression was significantly higher in human epithelial ovarian cancer (EOC) tissues than in normal ovarian tissues and that higher levels of Bach1 were associated with tumor stage and poorer overall and progression-free survival. We found that Bach1 enhanced the expression of epithelial-mesenchymal transition (EMT) genes, including Slug and Snail, and promoted cell migration by recruiting HMGA2 in the human EOC cell line A2780. Bach1 overexpression enhanced and Bach1 knockout reduced the expression of Slug and the metastasis of EOC cells in a tumor metastasis mouse model. Bach1 expression was positively correlated with Slug and HMGA2 expression in human ovarian cancer tissues. In addition, Bach1 activated p-AKT and p-p70S6K, increased the expression of cyclin D1, and promoted the growth of ovarian cancer cells in vitro and tumor xenografts in vivo. Together, our findings reveal that Bach1 enhances tumor growth and recruits HMGA2 to promote EMT and ovarian cancer metastasis.

Bach1: Function, Regulation, and Involvement in Disease

The transcription factor BTB and CNC homology 1 (Bach1) is widely expressed in most mammalian tissues and functions primarily as a transcriptional suppressor by heterodimerizing with small Maf proteins and binding to Maf recognition elements in the promoters of targeted genes. It has a key regulatory role in the production of reactive oxygen species, cell cycle, heme homeostasis, hematopoiesis, and immunity and has been shown to suppress ischemic angiogenesis and promote breast cancer metastasis. This review summarizes how Bach1 controls these and other cellular and physiological and pathological processes. Bach1 expression and function differ between different cell types. Thus, therapies designed to manipulate Bach1 expression will need to be tightly controlled and tailored for each specific disease state or cell type.