B-Myb Is Up-Regulated and Promotes Cell Growth and Motility in Non-Small Cell Lung Cancer

Genome-wide binding analysis unveils critical implication of B-Myb-mediated transactivation in cancers

B-Myb, also known as MYB proto-oncogene like 2 (MYBL2), is an important transcription factor implicated in transcription regulation, cell cycle and tumorigenesis. However, the molecular mechanism underlying B-Myb-controlled transactivation in different cell contexts as well as its functional implication in cancers remains elusive. In this study, we have conducted a comprehensive genome-wide analysis of B-Myb binding sites in multiple immortalized or cancer cell lines and identified its critical target genes. The results revealed that B-Myb regulates a common set of core cell cycle genes and cell type-specific genes through collaboration with other important transcription factors (e.g. NFY and MuvB complex) and binding to cell type-invariant promoters and cell type-specific enhancers and super-enhancers. KIF2C, UBE2C and MYC were further validated as B-Myb target genes. Loss-of-function analysis demonstrated that KIF2C knockdown inhibited tumor cell growth both in vitro and in vivo, suppressed cell motility and cell cycle progression, accompanied with defects in microtubule organization and mitosis, strongly suggesting that KIF2C is a critical regulator of cancer cell growth and mitosis, and maintains high cancer cell motility ability and microtubule dynamics. Pan-cancer transcriptomic analysis revealed that the overexpression of both B-Myb and KIF2C presents as independent prognostic markers in various types of cancer. Notably, B-Myb associates with NFYB, binds to target gene promoters, enhancers and super-enhancers, and provokes a cascade of oncogenic gene expression profiles in cancers. Overall, our results highly suggest the critical implication of B-Myb-mediated gene regulation in cancers, and the promising therapeutic and prognostic potentials of B-Myb and KIF2C for cancer diagnosis and treatment.

MYBL2 Drives Prostate Cancer Plasticity: Inhibiting Its Transcriptional Target CDK2 for RB1-Deficient Neuroendocrine Prostate Cancer

Phenotypic plasticity is a recognized mechanism driving therapeutic resistance in patients with prostate cancer. Although underlying molecular causations driving phenotypic plasticity have been identified, therapeutic success is yet to be achieved. To identify putative master regulator transcription factors (MR-TF) driving phenotypic plasticity in prostate cancer, this work utilized a multiomic approach using genetically engineered mouse models of prostate cancer combined with patient data to identify MYB proto-oncogene like 2 (MYBL2) as a significantly enriched transcription factor in prostate cancer exhibiting phenotypic plasticity. Genetic inhibition of Mybl2 using independent murine prostate cancer cell lines representing phenotypic plasticity demonstrated Mybl2 loss significantly decreased in vivo growth as well as cell fitness and repressed gene expression signatures involved in pluripotency and stemness. Because MYBL2 is currently not druggable, a MYBL2 gene signature was employed to identify cyclin-dependent kinase-2 (CDK2) as a potential therapeutic target. CDK2 inhibition phenocopied genetic loss of Mybl2 and significantly decreased in vivo tumor growth associated with enrichment of DNA damage. Together, this work demonstrates MYBL2 as an important MR-TF driving phenotypic plasticity in prostate cancer. Furthermore, high MYBL2 activity identifies prostate cancer that would be responsive to CDK2 inhibition.

SIGNIFICANCE

Prostate cancers that escape therapy targeting the androgen receptor signaling pathways via phenotypic plasticity are currently untreatable. Our study identifies MYBL2 as a MR-TF in phenotypic plastic prostate cancer and implicates CDK2 inhibition as a novel therapeutic target for this most lethal subtype of prostate cancer.

G-quadruplex forming motifs in the promoter region of the B-MYB proto-oncogene

To combat cancer, a comprehensive understanding of the molecular mechanisms and behaviors involved in carcinogenesis is crucial, as tumorigenesis is a complex process influenced by various genetic events and disease hallmarks. The B-MYB gene encodes a transcription factor involved in cell cycle regulation, survival, and differentiation in normal cells. B-MYB can be transformed into an oncogene through mutations, and abnormal expression of B-MYB has been identified in various cancers, including lung cancer, and is associated with poor prognosis. Targeting this oncogene is a promising approach for anti-cancer drug design. B-MYB has been deemed undruggable in previous reports, necessitating the search for novel therapeutic options. In this study, we found that the B-MYB gene promoter contains several G/C rich motifs compatible with G-quadruplex (G4) formation. We investigated and validated the existence of G4 structures in the promoter region of B-MYB, first in vitro using a combination of bioinformatics, biophysical, and biochemical methods, then in cell with the recently developed G4access method.

Integrative transcriptome analysis identifies MYBL2 as a poor prognosis marker for osteosarcoma and a pan-cancer marker of immune infiltration

MYBL2 (MYB proto-oncogene like 2) is an emerging prognostic marker for malignant tumors, and its potential role in osteosarcoma and its relationship with immune infiltration in pan-cancer is yet to be elucidated. We constructed a transcription factor activity profile of osteosarcoma using the single-cell regulatory network inference algorithm based on single-cell RNA sequencing data obtained from the Gene Expression Omnibus. Subsequently, we calculated the extent of MYBL2 activation in malignant proliferative osteoblasts. We also explored the association between MYBL2 and chemotherapy resistance in osteosarcoma. Furthermore, we systematically correlated MYBL2 with immunological signatures in the tumor microenvironment in pan-cancer, including immune cell infiltration, immune checkpoints, and tumor immunotherapy prognosis. Finally, we developed and validated a risk score (MRGS), derived an osteosarcoma risk score nomogram based on MRGS, and tested its ability to predict prognosis. MYBL2 and gene enrichment analyses in osteosarcoma and pan-cancer revealed that MYBL2 was positively correlated with cell proliferation and tumor immune pathways. MYBL2 expression positively correlated with SLC19A1 in pan-cancer and osteosarcoma cell lines. Pan-cancer immune infiltration analysis revealed that MYBL2 was correlated with myeloid-derived suppressor cells, Th2 cell infiltration, CD276, RELT gene expression, and tumor mutation burden. In summary, MYBL2 regulates proliferation, progression, and immune infiltration in osteosarcoma and pan-cancer. Therefore, we found that MYBL2 could be used as a potential marker for predicting the osteosarcoma prognosis. Patients with osteosarcoma and high MYBL2 expression are theoretically more sensitive to methotrexate. An osteosarcoma prognostic nomogram can provide new ideas in the search for osteosarcoma prognostic markers.

Analysis of cancer-associated fibroblasts related genes identifies COL11A1 associated with lung adenocarcinoma prognosis

BACKGROUND

The treatment of lung adenocarcinoma is difficult due to the limited therapeutic options. Cancer-associated fibroblasts play an important role in the development of cancers. This study aimed to identify a promising molecular target associated with cancer-associated fibroblasts for the treatment of lung adenocarcinoma.

METHODS

The Cancer Genome Atlas lung adenocarcinoma dataset was used to screen hub genes associated with cancer-associated fibroblasts via the EPIC algorithm and Weighted Gene Co-expression Network Analysis. Multiple databases were used together with our data to verify the differential expression and survival of COL11A1. Functional enrichment analysis and the single-cell TISCH database were used to elucidate the mechanisms underlying COL11A1 expression. The correlation between COL11A1 and immune checkpoint genes in human cancers was also evaluated.

RESULTS

Using the EPIC algorithm and Weighted Gene Co-expression Network Analysis, 13 hub genes associated with cancer-associated fibroblasts in lung adenocarcinoma were screened. Using the GEPIA database, Kaplan-Meier Plotter database, GSE72094, GSE75037, GSE32863, and our immunohistochemistry experiment data, we confirmed that COL11A1 overexpresses in lung adenocarcinoma and that high expression of COL11A1 is associated with a poor prognosis. COL11A1 has a genetic alteration frequency of 22% in patients with lung adenocarcinoma. COL11A1 is involved in the extracellular matrix activities of lung adenocarcinoma. Using the TISCH database, we found that COL11A1 is mainly expressed by cancer-associated fibroblasts in the tumor microenvironment rather than by lung adenocarcinoma cells. Finally, we found that COL11A1 is positively correlated with HAVCR2(TIM3), CD274 (PD-L1), CTLA4, and LAG3 in lung adenocarcinoma.

CONCLUSION

COL11A1 may be expressed and secreted by cancer-associated fibroblasts, and a high expression of COL11A1 may result in T cell exhaustion in the tumor microenvironment of lung adenocarcinoma. COL11A1 may serve as an attractive biomarker to provide new insights into cancer therapeutics.

B-Myb deficiency boosts bortezomib-induced immunogenic cell death in colorectal cancer

B-Myb has received considerable attention for its critical tumorigenic function of supporting DNA repair. However, its modulatory effects on chemotherapy and immunotherapy have rarely been reported in colorectal cancer. Bortezomib (BTZ) is a novel compound with chemotherapeutic and immunotherapeutic effects, but it fails to work in colorectal cancer with high B-Myb expression. The present study was designed to investigate whether B-Myb deletion in colorectal cancer could potentiate the immune efficacy of BTZ against colorectal cancer and to clarify the underlying mechanism. Stable B-Myb knockdown was induced in colorectal cancer cells, which increased apoptosis of the cancer cells relative to the control group in vitro and in vivo. We found that BTZ exhibited more favourable efficacy in B-Myb-defective colorectal cancer cells and tumor-bearing mice. BTZ treatment led to differential expression of genes enriched in the p53 signaling pathway promoted more powerful downstream DNA damage, and arrested cell cycle in B-Myb-defective colorectal cancer. In contrast, recovery of B-Myb in B-Myb-defective colorectal cancer cells abated BTZ-related DNA damage, cell cycle arrest, and anticancer efficacy. Moreover, BTZ promoted DNA damage-associated enhancement of immunogenicity, as indicated by potentiated expression of HMGB1 and HSP90 in B-Myb-defective cells, thereby driving M1 polarization of macrophages. Collectively, B-Myb deletion in colorectal cancer facilitates the immunogenic death of cancer cells, thereby further promoting the immune efficacy of BTZ by amplifying DNA damage. The present work provides an effective molecular target for colorectal cancer immunotherapy with BTZ.

From modulation of cellular plasticity to potentiation of therapeutic resistance: new and emerging roles of MYB transcription factors in human malignancies

MYB transcription factors are encoded by a large family of highly conserved genes from plants to vertebrates. There are three members of the MYB gene family in human, namely, MYB, MYBL1, and MYBL2 that encode MYB/c-MYB, MYBL1/A-MYB, and MYBL2/B-MYB, respectively. MYB was the first member to be identified as a cellular homolog of the v-myb oncogene carried by the avian myeloblastosis virus (AMV) causing leukemia in chickens. Under the normal scenario, MYB is predominantly expressed in hematopoietic tissues, colonic crypts, and neural stem cells and plays a role in maintaining the undifferentiated state of the cells. Over the years, aberrant expression of MYB genes has been reported in several malignancies and recent years have witnessed tremendous progress in understanding of their roles in processes associated with cancer development. Here, we review various MYB alterations reported in cancer along with the roles of MYB family proteins in tumor cell plasticity, therapy resistance, and other hallmarks of cancer. We also discuss studies that provide mechanistic insights into the oncogenic functions of MYB transcription factors to identify potential therapeutic vulnerabilities.

KRT17 from skin cells with high glucose stimulation promotes keratinocytes proliferation and migration

Impaired diabetic wound healing is an important issue in diabetic complications. Proliferation and migration of keratinocytes are major processes of skin wound repair after injury. However, hyperkeratosis can affect the speed of wound healing. Based on the results of preliminary experiments on increased KRT17 expression after high glucose stimulation of human skin tissue cells, a cell model of human immortalized keratinocyte (HaCaT) stimulation with different concentrations of KRT17 was established in vitro, and the promotion in cell proliferation and migration were discovered. KRT17 silencing promoted diabetic wound healing in the db/db diabetic wound model. Transcriptome sequencing (RNA-seq) was performed on HaCaT cells after KRT17 stimulation, and analysis showed significant enrichment in the PI3K-AKT signaling pathway, in which the regulation of cell c-MYB mRNA, a key molecule regulating cell proliferation and migration, was significantly upregulated. In vitro assays showed increased c-MYB expression and enhanced pAKT activity after HaCaT cell stimulation by KRT17. We speculate that KRT17 is upregulated under high glucose and promotes keratinocyte proliferation and migration caused hyperkeratosis, through the c-MYB/PI3K-AKT pathway, contributing to delayed wound healing.

Up-regulation of ABCG2 by MYBL2 deletion drives Chlorin e6-mediated photodynamic therapy resistance in colorectal cancer

OBJECTIVE

Photodynamic therapy (PDT) is an effective therapeutic strategy for colorectal cancer at an early stage. However, malignant cells' resistance to photodynamic agents can lead to treatment failure. MYBL2 (B-Myb) is an oncogene in colorectal carcinogenesis and development, for which little research has focused on its effect on drug resistance.

MATERIALS AND METHODS

In the present work, a colorectal cancer cell line with a stable knockdown of MYBL2 (ShB-Myb) was constructed first. Chlorin e6 (Ce6) was utilized to induced PDT. The anti-cancer efficacy was measured by CCK-8, PI staining, and Western blots. The drug uptake of Ce6 was assayed by flow cytometry and confocal microscopy. The ROS generation was detected by the CellROX probe. DDSB and DNA damage were assayed through comet experiment and Western blots. The over-expression of MYBL2 was conducted by MYBL2 plasmid.

RESULTS

The findings indicated that the viability of ShB-Myb treated with Ce6-PDT was not decreased compared to control SW480 cells (ShNC), which were resistant to PDT. Further investigation revealed reduced photosensitizer enrichment and mitigated oxidative DNA damage in colorectal cancer cells with depressed MYBL2. It turned out that SW480 cells knocking down MYBL2 showed phosphorylation of NF-κB and led to up-regulation of ABCG2 expression thereupon. When MYBL2 was replenished back in MYBL2-deficient colorectal cancer cells, phosphorylation of NF-κB was blocked and ABCG2 expression up-regulation was suppressed. Additionally, replenishment of MYBL2 also increased the enrichment of Ce6 and the efficacy of PDT.

CONCLUSION

In summary, MYBL2 absence in colorectal cancer contributes to drug resistance by activating NF-κB to up-regulate ABCG2 and thereby leading to photosensitizer Ce6 efflux. This study provides a novel theoretical basis and strategy for how to effectively improve the anti-tumor efficacy of PDT.

SKA2-mediated transcriptional downregulation of the key enzyme of CoQ10 biosynthesis PDSS2 in lung cancer cells

Lung cancer is the leading cause of cancer-associated mortality worldwide. SKA2 is a novel cancer-associated gene that plays critical roles in both cell cycle and tumorigenesis including lung cancer. However, the molecular mechanisms underlying its implication in lung cancer remains elusive. In this study, we first analyzed the gene expression profiling after SKA2 knockdown, and identified several candidate downstream target genes of SKA2, including PDSS2, the first key enzyme in CoQ10 biosynthesis pathway. Further experiments verified that SKA2 remarkably repressed PDSS2 gene expression at both mRNA and protein levels. Luciferase reporter assay showed that SKA2 repressed PDSS2 promoter activity through its Sp1-binding sites. Co-immunoprecipitation assay demonstrated that SKA2 associated with Sp1. Functional analysis revealed that PDSS2 remarkably suppressed lung cancer cell growth and motility. Furthermore, SKA2-induced malignant features can be also significantly attenuated by PDSS2 overexpression. However, CoQ10 treatment showed no obvious effects on lung cancer cell growth and motility. Of note, PDSS2 mutants with no catalytic activity exhibited comparable inhibitory effects on the malignant features of lung cancer cells and could also abrogate SKA2-promoted malignant phenotypes in lung cancer cells, highly suggesting a non-enzymatic tumor-suppressing activity of PDSS2 in lung cancer cells. The levels of PDSS2 expression were significantly decreased in lung cancer samples, and lung cancer patients with high expression of SKA2 and low expression of PDSS2 displayed remarkable poor prognosis. Collectively, our results demonstrated that PDSS2 is a novel downstream target gene of SKA2 in lung cancer cells, and the SKA2-PDSS2 transcriptional regulatory axis functionally contributes to human lung cancer cell malignant phenotypes and prognosis.

A targetable MYBL2-ATAD2 axis governs cell proliferation in ovarian cancer

The chromatin-modifying enzyme ATAD2 confers oncogenic competence and proliferative advantage in malignances. We previously identified ATAD2 as a marker and driver of cell proliferation in ovarian cancer (OC); however, the mechanisms whereby ATAD2 is regulated and involved in cell proliferation are still unclear. Here, we disclose that ATAD2 displays a classical G2/M gene signature, functioning to facilitate mitotic progression. ATAD2 ablation caused mitotic arrest and decreased the ability of OC cells to pass through nocodazole-arrested mitosis. ChIP-seq data analyses demonstrated that DREAM and MYBL2-MuvB (MMB), two switchable MuvB-based complexes, bind the CHR elements in the ATAD2 promoter, representing a typical feature and principle mechanism of the periodic regulation of G2/M genes. As a downstream target of MYBL2, ATAD2 deletion significantly impaired MYBL2-driven cell proliferation. Intriguingly, ATAD2 silencing also fed back to destabilize the MYBL2 protein. The significant coexpression of MYBL2 and ATAD2 at both the bulk tissue and single-cell levels highlights the existence of the MYBL2-ATAD2 signaling in OC patients. This signaling is activated during tumorigenesis and correlated with TP53 mutation, and its hyperactivation was found especially in high-grade serous and drug-resistant OCs. Disrupting this signaling by CRISPR/Cas9-mediated ATAD2 ablation inhibited the in vivo growth of OC in a subcutaneous tumor xenograft mouse model, while pharmacologically targeting this signaling with an ATAD2 inhibitor demonstrated high therapeutic efficacy in both drug-sensitive and drug-resistant OC cells. Collectively, we identified a novel MYBL2-ATAD2 proliferative signaling axis and highlighted its potential application in developing new therapeutic strategies, especially for high-grade serous and drug-resistant OCs.

[High expression of MYBL2 promotes progression and predicts a poor survival outcome of prostate cancer]

OBJECTIVE

To explore the correlation of MYB proto-oncogene like 2 (MYBL2) with biological behaviors and clinical prognosis of prostate cancer (PCa).

METHODS

We detected Mybl2 mRNA expression in 45 pairs of PCa and adjacent tissues using real-time quantitative PCR, and analyzed the correlation of high (23 cases) and low expression (22 cases) of Mybl2 with clinicopathological features and prognosis of the patients using nonparametric test, Kaplan-Meier survival analysis and univariate and multivariate Cox regression. The results were verified by analysis of the data from Cancer Genome Atlas (TCGA) microarray database, and the molecular pathways were identified by gene set enrichment analysis (GSEA). The CIBERPORT algorithm was used to identify the correlations between Mybl2 expression and tumor microenvironment of PCa. We also tested the effects of MYBL2 knockdown on proliferation and invasion of PCa cell lines using cell counting kit-8 and Transwell assays and observed the growth of PC3 cell xenograft with MYBL2 knockdown in nude mice and the expression levels of Ki-67 in the xenograft using immunohistochemistry.

RESULTS

Mybl2 expression was significantly elevated in PCa tissues in close correlation with Gleason score and clinical and pathological stage of the tumor (P < 0.01) but not with the patients' age. Kaplan-Meier analysis indicated a significant negative correlation of high Mybl2 expression with recurrence-free survival (P < 0.05), but not with the overall survival of the patients. The data from TCGA suggested that clinical and pathological stages were independent prognostic factors for recurrence-free survival, and our data indicated that clinical stage and Gleason score were independent prognostic factors of PCa (P < 0.05). GSEA suggested that Mybl2 expression was related with the pathways involving immune function, cell adhesion, and cytokine secretion; CIBERPORT analysis suggested the involvement of Mybl2 expression with memory B cells and resting mast cells (P < 0.05). In LNCaP and PC-3 cells, MYBL2 knockdown significantly inhibited cell proliferation and invasion (P < 0.05); in the tumor-bearing nude mice, the xenografts derived from PC-3 cells with MYBL2 knockdown exhibited a lowered mean tumor weight and positivity rate for Ki67 (P < 0.05).

CONCLUSION

Mybl2 is an oncogene related with multiple pathological indicators of PCa and can serve as a potential prognostic marker as well as a therapeutic target for patients with PCa.

Collagen XI Alpha 1 Chain, a Novel Therapeutic Target for Cancer Treatment

The extracellular matrix (ECM) plays an important role in the progression of cancer. Collagen is the most abundant component in ECM, and is involved in the biological formation of cancer. Although type XI collagen is a minor fibrillar collagen, collagen XI alpha 1 chain (COL11A1) expression has been found to be upregulated in a variety of human cancers including colorectal, esophagus, glioma, gastric, head and neck, lung, ovarian, pancreatic, salivary gland, and renal cancers. High levels of COL11A1 usually predict poor prognosis, owing to its association with angiogenesis, invasion, and drug resistance in cancer. However, little is known about the specific mechanism through which COL11A1 regulates tumor progression. Here, we have organized and summarized recent developments regarding the interactions between COL11A1 and intracellular signaling pathways and selected therapeutic agents targeting COL11A1, as these indicate its potential as a target for treatment of cancers, especially epithelial ovarian cancer.

E2F2 promotes lung adenocarcinoma progression through B-Myb- and FOXM1-facilitated core transcription regulatory circuitry

Lung adenocarcinoma (LUAD) causes severe cancer death worldwide. E2F2 is a canonical transcription factor implicated in transcription regulation, cell cycle and tumorigenesis. The role of E2F2 as well as its transcription regulatory network in LUAD remains obscure. In this study, we constructed a weighted gene co-expression network and identified several key modules and networks overrepresented in LUAD, including the E2F2-centered transcription regulatory network. Function analysis revealed that E2F2 overexpression accelerated cell growth, cell cycle progression and cell motility in LUAD cells whereas E2F2 knockdown inhibited these malignant phenotypes. Mechanistic investigations uncovered various E2F2-regulated downstream genes and oncogenic signaling pathways. Notably, three core transcription factors of E2F2, B-Myb and FOXM1 from the LUAD transcription regulatory network exhibited positive expression correlation, associated with each other, mutually transactivated each other, and regulated similar downstream gene cascades, hence constituting a consolidated core transcription regulatory circuitry. Moreover, E2F2 could promote and was essentially required for LUAD growth in orthotopic mouse models. Prognosis modeling revealed that a two-gene signature of E2F2 and PLK1 from the transcription regulatory circuitry remarkably stratified patients into low- and high-risk groups. Collectively, our results clarified the critical roles of E2F2 and the exquisite core transcription regulatory circuitry of E2F2/B-Myb/FOXM1 in LUAD progression.

Downstream Regulatory Network of MYBL2 Mediating Its Oncogenic Role in Melanoma

The transcription factor MYBL2 is widely expressed in proliferating cells. Aberrant expression of MYBL2 contributes to tumor malignancy and is associated with poor patient prognosis. However, the downstream transcriptional network that mediates its oncogenic properties remains elusive. In the present study, we observed that MYBL2 was overexpressed in malignant and metastatic melanoma patient samples and that the high expression level of MYBL2 was significantly associated with poor prognosis. A loss-of-function study demonstrated that MYBL2 depletion significantly decreased cell proliferation and migration and prevented cell cycle progression. We also determined that MYBL2 promoted the formation of melanoma stem-like cell populations, indicating its potential as a therapeutic target for treating resistant melanoma. Mechanistically, we constructed an MYBL2 regulatory network in melanoma by integrating RNA-seq and ChIP-seq data. EPPK1, PDE3A, and FCGR2A were identified as three core target genes of MYBL2. Importantly, multivariate Cox regression and survival curve analysis revealed that PDE3A and EPPK1 were negatively correlated with melanoma patient survival; however, FCGR2A was positively correlated with patient survival. Overall, our findings elucidate an MYBL2 regulatory network related to cell proliferation and cancer development in melanoma, suggesting that MYBL2 may be potentially targeted for melanoma diagnosis and treatment.

MYBL2 accelerates epithelial-mesenchymal transition and hepatoblastoma metastasis via the Smad/SNAI1 pathway

Hepatoblastoma (HB) accounts for the majority of hepatic malignancies in children. Although the prognosis of patients with HB has improved in past decades, metastasis is an indicator of poor overall survival. Herein, we applied single-cell RNA sequencing to explore the transcriptomic profiling of 25,264 metastatic cells isolated from the lungs of two patients with HB. The transcriptomes uncovered the heterogeneity of malignant cells after metastatic lung colonization, and these cells had varied expression signatures associated with the cell cycle, epithelial-mesenchymal plasticity, and hepatic differentiation. Single-cell regulatory network inference and clustering (SCENIC) was utilized to identify the co-expressed transcriptional factors which regulated and represented the different cell states. We further screened the key factor by bioinformatics analysis and found that MYBL2 upregulation was significantly associated with metastasis and poor prognosis. The relationship between ectopic MYBL2 and metastasis was subsequently proved by immunohistochemistry (IHC) of HB tissues, and the functions of MYBL2 in promoting proliferation, migration, and epithelial-to-mesenchymal transition (EMT) were verified by in vitro and in vivo assays. Importantly, the levels of Smad2/3 phosphorylation and SNAI1 expression were increased in MYBL2-transfected cells. Consequently, these results indicated that the MYBL2-controlled Smad/SNAI1 pathway induced EMT and promoted HB tumorigenesis and metastasis.

Intricate crosstalk between MYB and noncoding RNAs in cancer

MYB is often overexpressed in malignant tumors and plays a carcinogenic role in the initiation and development of cancer. Deletion of the MYB regulatory C-terminal domain may be a driving mutation leading to tumorigenesis, therefore, different tumor mechanisms produce similar MYB proteins. As MYB is a transcription factor, priority has been given to identifying the genes that it regulates. All previous attention has been focused on protein-coding genes. However, an increasing number of studies have suggested that MYB can affect the complexity of cancer progression by regulating tumor-associated noncoding RNAs (ncRNAs), such as microRNAs, long-non-coding RNAs and circular RNAs. ncRNAs can regulate the expression of numerous downstream genes at the transcription, RNA processing and translation levels, thereby having various biological functions. Additionally, ncRNAs play important roles in regulating MYB expression. This review focuses on the intricate crosstalk between oncogenic MYB and ncRNAs, which play a pivotal role in tumorigenesis, including proliferation, apoptosis, angiogenesis, metastasis, senescence and drug resistance. In addition, we discuss therapeutic strategies for crosstalk between MYB and ncRNAs to prevent the occurrence and development of cancer.

Integrated Multiomics Analyses Revealing Different Molecular Profiles Between Early- and Late-Stage Lung Adenocarcinoma

The molecular differences in genetic and epigenetic profiling between early-stage (ES) and late-stage (LS) lung adenocarcinoma (LUAD), which might help to understand cancer progression and biomarker guided precision treatment, need further be investigated. In this study, we performed comprehensive analysis using multi-omics next-generation sequencing (NGS) on tissue samples from 7 ES (stage I) and 10 LS (stage III/IV) LUAD patients to study molecular characteristics between the two groups. Characterization of the genomic and transcriptomic profiles showed stage-specific somatic mutations, copy number variations (CNVs) and differentially expressed genes (DEGs). LS samples tend to have more TP53, ERBB2 and CHD4 mutations. Gene copy number loss occurs in immune-related gene pathways in the late stage of LUAD. ATAC-seq analysis showed that LS samples harbored more open chromatin peaks around promoter regions and transcription start sites (TSS) than ES samples. We then identified the known transcription factor (TF) binding motifs for the differentially abundant ATAC-seq peaks between the ES and LS samples and found distinct regulatory mechanisms related to each stage. Furthermore, integrative analysis of ATAC-seq with WGS and RNA-seq data showed that the degree of chromatin accessibility is related to copy number changes, and the open chromatin regions could directly regulate the expression of some DEGs. In conclusion, we performed a comprehensive multi-omics analysis of the early and late stages of LUAD and highlighted some important molecular differences in regulatory mechanisms during cancer progression. Those findings help to further understand mechanism and biomarker related targeted therapy.

Pan-cancer analysis indicates that MYBL2 is associated with the prognosis and immunotherapy of multiple cancers as an oncogene

MYBL2 has been demonstrated to be an oncogene in some cancers, but there is no pan-cancer analysis at the macro level. We used multiple online or offline bioinformatic tools to examine the effects of MYBL2 in human cancers. We first identified that MYBL2 was highly expressed and related to the stage and grade of most cancers. The results of survival analysis from two databases showed that high MYBL2 expression was positively correlated with a poor prognosis for most cancer patients. We observed a significant difference in the promoter methylation level of MYBL2 in cancers such as colon adenocarcinoma and liver hepatocellular carcinoma versus normal controls. We found that MYBL2 can affect the tumor immune microenvironment by influencing the immune infiltration level and expression level of CD4⁺ T cells, CD8⁺ T cells, cancer-associated fibroblasts (CAFs) and immune checkpoint-associated cells. Functional enrichment analysis of MYBL2 identified that MYBL2 can play a crucial role in cancers by regulating spliceosomes, DNA replication and the cell cycle. Moreover, we verified the function of MYBL2 in three cancer cells of glioma, breast cancers and liver cancers, and the results showed that MYBL2 can regulate the cell cycle and proliferation ability of cancers.

B-Myb accelerates colorectal cancer progression through reciprocal feed-forward transactivation of E2F2

B-Myb is an important transcription factor that plays a critical role in gene expression regulation and tumorigenesis. However, its functional implication in colorectal cancer remains elusive. In this study, we found that B-Myb was significantly upregulated at both mRNA and protein levels in colorectal cancer samples compared to non-tumor counterparts. B-Myb overexpression accelerated cell proliferation, cell cycle progression and cell motility in colorectal cancer cells, and promoted tumor growth in orthotopic nude mouse models in vivo. In contrast, B-Myb depletion inhibited these malignant phenotypes. Mechanistic investigations revealed that E2F2 was a novel transcriptional target of B-Myb and is essential to B-Myb-induced malignant phenotypes. Notably, B-Myb and E2F2 exhibited positive expression correlation, and interacted with each other in colorectal cancer cells. In addition to their autoregulatory mechanisms, B-Myb and E2F2 can also directly transactivate each other, thus constituting consolidated reciprocal feed-forward transactivation loops. Moreover, both B-Myb and E2F2 are required for the activation of ERK and AKT signaling pathways in colorectal cancer cells. Taken together, our data clarified a critical role for B-Myb in colorectal cancer and unraveled an exquisite mutual collaboration and reciprocal cross regulation between B-Myb and E2F2 that contribute to the malignant progression of human colorectal cancer.

Collagen XI alpha 1 chain, a potential therapeutic target for cancer

Extracellular matrix (ECM) plays an important role in the progression of cancer. Collagen is the most abundant component in ECM, and it is involved in the biological formation of cancer. Although type XI collagen is a minor fibrillar collagen, collagen XI alpha 1 chain (COL11A1) has been found to be upregulated in a variety of cancers including ovarian cancer, breast cancer, thyroid cancer, pancreatic cancer, non-small-cell lung cancer, and transitional cell carcinoma of the bladder. High levels of COL11A1 usually predict poor prognosis, while COL11A1 is related to angiogenesis, invasion, and drug resistance of cancer. However, little is known about the specific mechanism by which COL11A1 regulates tumor progression. Here, we have organized and summarized the recent developments regarding elucidation of the relationship between COL11A1 and various cancers, as well as the interaction between COL11A1 and intracellular signaling pathways. In addition, we have selected therapeutic agents targeting COL11A1. All these indicate the possibility of using COL11A1 as a target for cancer treatment.

Cell cycle dysregulation with overexpression of KIF2C/MCAK is a critical event in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common malignant carcinoma of the head and neck, and the biological mechanisms underlying the pathogenesis of NPC remain not fully understood. In the present study, we systematically analyzed four independent NPC transcriptomic datasets and focused on identifying the critical molecular networks and novel key hub genes implicated in NPC. We found totally 170 common overlapping differentially expressed genes (DEGs) in the four NPC datasets. GO and KEGG pathway analysis revealed that cell cycle dysregulation is a critical event in NPC. Protein-protein interaction (PPI) network analysis identified a 15 hub-gene core network with overexpressed kinesin family member 2C (KIF2C) as a central regulator. Loss-of-function study demonstrated that knockdown of KIF2C significantly inhibited cell growth and cell motility, and delayed cell cycle progression, accompanied with dramatic mitotic defects in spindle formation in NPC cells. RNA-seq analysis revealed that KIF2C knockdown led to deregulation of various downstream genes. KIF2C could also regulate the AKT/mTOR pathways, and enhance paclitaxel sensitivity in NPC cells. Taken together, our results suggest that cell cycle dysregulation is a critical event during NPC pathogenesis and KIF2C is a novel key mitotic hub gene with therapeutic potential in NPC.

Ionizing radiation induces epithelial-mesenchymal transition in human bronchial epithelial cells

Objective: The present study aimed to analyze the mechanism by which long-term occupational exposure of workers to low-dose ionizing irradiation induces epithelial–mesenchymal transition (EMT) of the human bronchial epithelial cells using transcriptome profiling.

Methods: RNA-seq transcriptomics was used to determine gene expression in blood samples from radiation-exposed workers followed by bioinformatics analysis. Normal bronchial epithelial cells (16HBE) were irradiated for different durations and subjected to immunofluorescence, Western blotting, scratch healing, and adhesion assays to detect the progression of EMT and its underlying molecular mechanisms.

Results: Transcriptomics revealed that exposure to ionizing radiation led to changes in the expression of genes related to EMT, immune response, and migration. At increased cumulative doses, ionizing radiation-induced significant EMT, as evidenced by a gradual decrease in the expression of E-cadherin, increased vimentin, elevated migration ability, and decreased adhesion capability of 16HBE cells. The expression of fibronectin 1 (FN1) showed a gradual increase with the progression of EMT, and may be involved in EMT.

Conclusion: Ionizing radiation induces EMT. FN1 may be involved in the progression of EMT and could serve as a potential biomarker for this process.

A MAPK/miR-29 Axis Suppresses Melanoma by Targeting MAFG and MYBL2

The miR-29 family of microRNAs is encoded by two clusters, miR-29b1~a and miR-29b2~c, and is regulated by several oncogenic and tumor suppressive stimuli. While in vitro evidence suggests a tumor suppressor role for miR-29 in melanoma, the mechanisms underlying its deregulation and contribution to melanomagenesis have remained elusive. Using various in vitro systems, we show that oncogenic MAPK signaling paradoxically stimulates transcription of pri-miR-29b1~a and pri-miR-29b2~c, the latter in a p53-dependent manner. Expression analyses in melanocytes, melanoma cells, nevi, and primary melanoma revealed that pri-miR-29b2~c levels decrease during melanoma progression. Inactivation of miR-29 in vivo with a miRNA sponge in a rapid melanoma mouse model resulted in accelerated tumor development and decreased overall survival, verifying tumor suppressive potential of miR-29 in melanoma. Through integrated RNA sequencing, target prediction, and functional assays, we identified the transcription factors MAFG and MYBL2 as bona fide miR-29 targets in melanoma. Our findings suggest that attenuation of miR-29b2~c expression promotes melanoma development, at least in part, by derepressing MAFG and MYBL2.

MYB oncoproteins: emerging players and potential therapeutic targets in human cancer

MYB transcription factors are highly conserved from plants to vertebrates, indicating that their functions embrace fundamental mechanisms in the biology of cells and organisms. In humans, the MYB gene family is composed of three members: MYB, MYBL1 and MYBL2, encoding the transcription factors MYB, MYBL1, and MYBL2 (also known as c-MYB, A-MYB, and B-MYB), respectively. A truncated version of MYB, the prototype member of the MYB family, was originally identified as the product of the retroviral oncogene v-myb, which causes leukaemia in birds. This led to the hypothesis that aberrant activation of vertebrate MYB could also cause cancer. Despite more than three decades have elapsed since the isolation of v-myb, only recently investigators were able to detect MYB genes rearrangements and mutations, smoking gun evidence of the involvement of MYB family members in human cancer. In this review, we will highlight studies linking the activity of MYB family members to human malignancies and experimental therapeutic interventions tailored for MYB-expressing cancers.

Collagen Type XI Alpha 1 (COL11A1): A Novel Biomarker and a Key Player in Cancer

Collagen type XI alpha 1 (COL11A1), one of the three alpha chains of type XI collagen, is crucial for bone development and collagen fiber assembly. Interestingly, COL11A1 expression is increased in several cancers and high levels of COL11A1 are often associated with poor survival, chemoresistance, and recurrence. This review will discuss the recent discoveries in the biological functions of COL11A1 in cancer. COL11A1 is predominantly expressed and secreted by a subset of cancer-associated fibroblasts, modulating tumor-stroma interaction and mechanical properties of extracellular matrix. COL11A1 also promotes cancer cell migration, metastasis, and therapy resistance by activating pro-survival pathways and modulating tumor metabolic phenotype. Several inhibitors that are currently being tested in clinical trials for cancer or used in clinic for other diseases, can be potentially used to target COL11A1 signaling. Collectively, this review underscores the role of COL11A1 as a promising biomarker and a key player in cancer.

Association between B-Myb proto-oncogene and the development of malignant tumors

B-Myb is a critical transcription factor in regulating cell cycle. Dysregulated expression of B-Myb promotes tumor formation and development. B-Myb is a proto-oncogene ubiquitously expressed in proliferating cells, which maintains normal cell cycle progression. It participates in cell apoptosis, tumorigenesis and aging. In addition, B-Myb is overexpressed in several malignant tumors, including breast cancer, lung cancer and hepatocellular carcinoma, and is associated with tumor development. B-Myb expression is also associated with the prognosis of patients with malignant tumors. Both microRNAs and E2F family of transcription factors (E2Fs) contribute to the function of B-Myb. The present review highlights the association between B-Myb and malignant tumors, and offers a theoretical reference for the diagnosis and treatment of malignant tumors.

Hsa_circ_0018818 knockdown suppresses tumorigenesis in non-small cell lung cancer by sponging miR-767-3p

To identify potential therapeutic targets in non-small cell lung cancer NSCLC, we conducted a bioinformatics analysis of circRNAs differentially expressed between NSCLC tissues and adjacent normal tissues. Cell proliferation and apoptosis was assessed using CCK-8 and flow cytometry, respectively. A connection between hsa_circ_0018818 and miR-767-3p was confirmed in dual luciferase reporter assays. Gene and protein expression in NSCLC cells were measured using quantitative PCR and Western-blotting, respectively. And a xenograft tumor model was established to assess the function of hsa_circ_0018818 in NSCLC in vivo. Hsa_circ_0018818 was greatly upregulated in NSCLC tumor tissues. Knocking down hsa_circ_0018818 using a targeted shRNA inhibited the proliferation and invasiveness of NSCLC cells and induced their apoptosis via the miR-767-3p/Nidogen 1 (NID1) signaling axis. Hsa_circ_0018818 knockdown also inactivated Epithelial-mesenchymal transition (EMT) process and PI3K/Akt signaling. In summary, hsa_circ_0018818 knockdown inhibited NSCLC tumorigenesis in vitro and in vivo, which suggests it could potentially serve as a target for the treatment of NSCLC.

Upregulation of MYBL2 independently predicts a poorer prognosis in patients with clear cell renal cell carcinoma

MYB protooncogene-like 2 (MYBL2) is a transcription factor that is upregulated and significantly associated with various human cancer types. However, the potential role of MYBL2 in clear cell renal cell carcinoma (ccRCC) is yet to be elucidated. Therefore, the expression and biological functions of MYBL2 in ccRCC were assessed in the current study using The Cancer Genome Atlas (TCGA). A Wilcoxon signed-rank test was performed to compare MYBL2 expression between ccRCC and normal tissues. Moreover, the association between MYBL2 expression and various clinicopathological factors was estimated using both the Wilcoxon signed-rank test and logistic regression. The differences in prognosis between patients with high- and low-MYBL2 expression were analyzed via the Kaplan-Meier method and Cox regression analysis. Finally, gene set enrichment analysis (GSEA) was performed to investigate the biofunctions of MYBL2 in ccRCC. It was revealed that MYBL2 was upregulated in ccRCC, and that the MYBL2 high-expression phenotype was significantly associated with sex, a high histological grade, an advanced clinical stage, tumor stage, lymph node metastasis, distant metastasis and poor overall survival (OS). It was also revealed, via the Cox regression analysis, that the upregulation of MYBL2 expression was able to independently predict a poor prognosis in patients with ccRCC. GSEA indicated that the intestinal immune network for IgA production, primary immunodeficiency, the janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway, the cytosolic DNA-sensing pathway, the p53 signaling pathway and the chemokine signaling pathway were all enriched in the high-MYBL2 expression datasets. In conclusion, the present findings indicate that MYBL2 may be used as an independent prognostic factor in patients with ccRCC.

Common and distinct features of potentially predictive biomarkers in small cell lung carcinoma and large cell neuroendocrine carcinoma of the lung by systematic and integrated analysis

BACKGROUND

Large-cell neuroendocrine carcinoma of the lung (LCNEC) and small-cell lung carcinoma (SCLC) are neuroendocrine neoplasms. However, the underlying mechanisms of common and distinct genetic characteristics between LCNEC and SCLC are currently unclear. Herein, protein expression profiles and possible interactions with miRNAs were provided by integrated bioinformatics analysis, in order to explore core genes associated with tumorigenesis and prognosis in SCLC and LCNEC.

METHODS

GSE1037 gene expression profiles were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in LCNEC and SCLC, as compared with normal lung tissues, were selected using the GEO2R online analyzer and Venn diagram software. Gene ontology (GO) analysis was performed using Database for Annotation, Visualization and Integrated Discovery. The biological pathway analysis was performed using the FunRich database. Subsequently, a protein-protein interaction (PPI) network of DEGs was generated using Search Tool for the Retrieval of Interacting Genes and displayed via Cytoscape software. The PPI network was analyzed by the Molecular Complex Detection app from Cytoscape, and 16 upregulated hub genes were selected. The Oncomine database was used to detect expression patterns of hub genes for validation. Furthermore, the biological pathways of these 16 hub genes were re-analyzed, and potential interactions between these genes and miRNAs were explored via FunRich.

RESULTS

A total of 384 DEGs were identified. A Venn diagram determined 88 common DEGs. The PPI network was constructed with 48 nodes and 221 protein pairs. Among them, 16 hub genes were extracted, 14 of which were upregulated in SCLC samples, as compared with normal lung specimens, and 10 were correlated with the cell cycle pathway. Furthermore, 57 target miRNAs for 8 hub genes were identified, among which 31 miRNAs were correlated with the progression of carcinoma, drug-resistance, radio-sensitivity, or autophagy in lung cancer.

CONCLUSION

This study provided effective biomarkers and novel therapeutic targets for diagnosis and prognosis of SCLC and LCNEC.

Identification of tumor suppressor miRNAs by integrative miRNA and mRNA sequencing of matched tumor-normal samples in lung adenocarcinoma

The roles of miRNAs in lung cancer have not yet been explored systematically at the genome scale despite their important regulatory functions. Here, we report an integrative analysis of miRNA and mRNA sequencing data for matched tumor–normal samples from 109 Korean female patients with non‐small‐cell lung adenocarcinoma (LUAD). We produced miRNA sequencing (miRNA‐Seq) and RNA‐Seq data for 48 patients and RNA‐Seq data for 61 additional patients. Subsequent differential expression analysis with stringent criteria yielded 44 miRNAs and 2322 genes. Integrative gene set analysis of the differentially expressed miRNAs and genes using miRNA–target information revealed several regulatory processes related to the cell cycle that were targeted by tumor suppressor miRNAs (TSmiR). We performed colony formation assays in A549 and NCI‐H460 cell lines to test the tumor‐suppressive activity of downregulated miRNAs in cancer and identified 7 novel TSmiRs (miR‐144‐5p, miR‐218‐1‐3p, miR‐223‐3p, miR‐27a‐5p, miR‐30a‐3p, miR‐30c‐2‐3p, miR‐338‐5p). Two miRNAs, miR‐30a‐3p and miR‐30c‐2‐3p, showed differential survival characteristics in the Tumor Cancer Genome Atlas (TCGA) LUAD patient cohort indicating their prognostic value. Finally, we identified a network cluster of miRNAs and target genes that could be responsible for cell cycle regulation. Our study not only provides a dataset of miRNA as well as mRNA sequencing from the matched tumor–normal samples, but also reports several novel TSmiRs that could potentially be developed into prognostic biomarkers or therapeutic RNA drugs.

Prognostic implications and oncogenic roles of MYBL2 protein expression in esophageal squamous-cell carcinoma

Background

The MYBL2 gene, a highly conserved member of the Myb transcription-factor family, has been implicated in the genesis and progression of many types of tumors.

Methods

We analyzed the expression of MYBL2 and Ki67 in tissue samples of esophageal squamous-cell carcinoma (ESCC) patients by immunohistochemistry. We further analyzed the effect of MYBL2 on cell proliferation and DNA replication using a CCK8 assay, 5-ethynyl-2′-deoxyuridine–retention assay, flow-cytometry analysis, real-time quantitative PCR, Western blot, and a xenograft model of ESCC cells in nude mice.

Results

MYBL2 expression was significantly higher in ESCC tissue when compared to the adjacent normal tissue (P=0.007). MYBL2 was found to be positively correlated with Ki67 (γ=0.286, P=0.003). Furthermore, Kaplan–Meier curves indicated that MYBL2 expression in ESCC tissue was associated with poor patient outcome (P<0.001), with MYBL2-positive patients who exhibited high Ki67 expression in ESCC tissue showing the worst prognosis for overall survival (P=0.003). Our in vitro results showed that downregulation of MYBL2 in ESCC cell lines inhibited cell proliferation and DNA replication (P<0.05 for both). We also found that loss of MYBL2 caused a reduction in levels of cell cycle-related G2/M proteins CDK1 and cyclin B1 in ESCC cells. In contrast, overexpression of MYBL2 caused an increase in these proteins. In vivo, we found that in nude mice that received cells knocked down for MYBL2, tumor growth was inhibited in comparison to the group that received control cells (P<0.05).

Conclusion

MYBL2 overexpression induces tumor proliferation in ESCC cells by regulating cell-cycle at the S and G2/M phase. Therefore, MYBL2 may serve as a novel prognostic biomarker in ESCC patients.

B-Myb Mediates Proliferation and Migration of Non-Small-Cell Lung Cancer via Suppressing IGFBP3

B-Myb has been shown to play an important oncogenic role in several types of human cancers, including non-small-cell lung cancer (NSCLC). We previously found that B-Myb is aberrantly upregulated in NSCLC, and overexpression of B-Myb can significantly promote NSCLC cell growth and motility. In the present study, we have further investigated the therapeutic potential of B-Myb in NSCLC. Kaplan–Meier and Cox proportional hazards analysis indicated that high expression of B-Myb is significantly associated with poor prognosis in NSCLC patients. A loss-of-function study demonstrated that depletion of B-Myb resulted in significant inhibition of cell growth and delayed cell cycle progression in NSCLC cells. Notably, B-Myb depletion also decreased NSCLC cell migration and invasion ability as well as colony-forming ability. Moreover, an in vivo study demonstrated that B-Myb depletion caused significant inhibition of tumor growth in a NSCLC xenograft nude mouse model. A molecular mechanistic study by RNA-seq analysis revealed that B-Myb depletion led to deregulation of various downstream genes, including insulin-like growth factor binding protein 3 (IGFBP3). Overexpression of IGFBP3 suppressed the B-Myb-induced proliferation and migration, whereas knockdown of IGFBP3 significantly rescued the inhibited cell proliferation and motility caused by B-Myb siRNA (small interfering RNA). Expression and luciferase reporter assays revealed that B-Myb could directly suppress the expression of IGFBP3. Taken together, our results suggest that B-Myb functions as a tumor-promoting gene via suppressing IGFBP3 and could serve as a novel therapeutic target in NSCLC.