Identification of EGF-NF-κB-FOXC1 signaling axis in basal-like breast cancer

Reciprocal regulation of forkhead box C1 and L1 cell adhesion molecule contributes to triple-negative breast cancer progression

PURPOSE

The potential of targeting forkhead box C1 (FOXC1) as a therapeutic approach for triple-negative breast cancer (TNBC) is promising. However, a comprehensive understanding of FOXC1 regulation, particularly upstream factors, remains elusive. Expression of the L1 cell adhesion molecule (L1CAM), a transmembrane glycoprotein associated with brain metastasis, was observed to be positively associated with FOXC1 transcripts. Thus, this study aims to investigate their relationship in TNBC progression.

METHODS

Publicly available FOXC1 and L1CAM transcriptomic data were obtained, and their corresponding proteins were analyzed in four TNBC cell lines. In BT549 cells, FOXC1 and L1CAM were individually silenced, while L1CAM was overexpressed in BT549-shFOXC1, MDA-MB-231, and HCC1937 cells. CCK-8, transwell, and wound healing assays were performed in these cell lines, and immunohistochemical staining was conducted in tumor samples.

RESULTS

A positive correlation between L1CAM and FOXC1 transcripts was observed in publicly available datasets. In BT549 cells, knockdown of FOXC1 led to reduced L1CAM expression at both the transcriptional and protein levels, and conversely, silencing of L1CAM decreased FOXC1 protein levels, but interestingly, FOXC1 transcripts remained largely unaffected. Overexpressing L1CAM resulted in increased FOXC1 protein expression without significant changes in FOXC1 mRNA levels. This trend was also observed in BT549-shFOXC1, MDA-MB-231-L1CAM, and HCC1937-L1CAM cells. Notably, alterations in FOXC1 or L1CAM levels corresponded to changes in cell proliferation, migration, and invasion capacities. Furthermore, a positive correlation between L1CAM and FOXC1 protein expression was detected in human TNBC tumors.

CONCLUSION

FOXC1 and L1CAM exhibit co-regulation at the protein level, with FOXC1 regulating at the transcriptional level and L1CAM regulating at the post-transcriptional level, and together they positively influence cell proliferation, migration, and invasion in TNBC.

Research progress on the regulatory mechanisms of FOXC1 expression in cancers and its role in drug resistance

The Forkhead box C1 (FOXC1) transcription factor is an important member of the FOX family. After initially being identified in triple-negative breast cancer (TNBC) with significant oncogenic function, FOXC1 was subsequently demonstrated to be involved in the development of more than 16 types of cancers. In recent years, increasing studies have focused on the deregulatory mechanisms of FOXC1 expression and revealed that FOXC1 expression was regulated at multiple levels including transcriptional regulation, post-transcription regulation and post-translational modification. Moreover, dysregulation of FOXC1 is also implicated in drug resistance in various types of cancer, especially in breast cancer, which further emphasizes the translational and clinical significance of FOXC1 as a therapeutic target in cancer treatment. This review summarizes recent findings on mechanisms of FOXC1 dysregulation in cancers and its role in chemoresistance, which will help to better understand the oncogenic role of FOXC1, overcome FOXC1-mediated drug resistance and develop targeted therapy for FOXC1 in cancers.

IGF-1-mediated FOXC1 overexpression induces stem-like properties through upregulating CBX7 and IGF-1R in esophageal squamous cell carcinoma

Substantial evidence attests to the pivotal role of cancer stem cells (CSC) in both tumorigenesis and drug resistance. A member of the forkhead box (FOX) family, FOXC1, assumes significance in embryonic development and organogenesis. Furthermore, FOXC1 functions as an overexpressed transcription factor in various tumors, fostering proliferation, enhancing migratory capabilities, and promoting drug resistance, while maintaining stem-cell-like properties. Despite these implications, scant attention has been devoted to its role in esophageal squamous cell carcinoma. Our investigation revealed a pronounced upregulation of FOXC1 expression in ESCC, correlating with a poor prognosis. The downregulation of FOXC1 demonstrated inhibitory effects on ESCC tumorigenesis, proliferation, and tolerance to chemotherapeutic agents, concurrently reducing the levels of stemness-related markers CD133 and CD44. Further studies validated that FOXC1 induces ESCC stemness by transactivating CBX7 and IGF-1R. Additionally, IGF-1 activated the PI3K/AKT/NF-κB and MEK/ERK/NF-κB pathways through its binding to IGF-1R, thereby augmenting FOXC1 expression. Conversely, suppressing FOXC1 impeded ESCC stemness induced by IGF-1. The presence of a positive feedback loop, denoted by IGF-1-FOXC1-IGF-1R, suggests the potential of FOXC1 as a prognostic biomarker for ESCC. Taken together, targeting the IGF-1-FOXC1-IGF-1R axis emerges as a promising approach for anti-CSC therapy in ESCC.

A review of biological targets and therapeutic approaches in the management of triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous, aggressive phenotype of breast cancer with associated chemoresistance. The development of chemo- or radioresistance could be attributed to diverse tumor microenvironments, overexpression of membrane proteins (transporters), epigenetic changes, and alteration of the cell signaling pathways/genes associated with the development of cancer stem cells (CSCs).

AIM OF REVIEW

Due to the diverse and heterogeneous nature of TNBC, therapeutic response to the existing modalities offers limited scope and thus results in reccurance after therapy. To establish landmark therapeutic efficacy, a number of novel therapeutic modalities have been proposed. In addition, reversal of the resistance that developed during treatment may be altered by employing appropriate therapeutic modalities. This review aims to discuss the plethora of investigations carried out, which will help readers understand and make an appropriate choice of therapy directed toward complete elimination of TNBC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This manuscript addresses the major contributory factors from the tumor microenvironment that are responsible for the development of chemoresistance and poor prognosis. The associated cellular events and molecular mechanism-based therapeutic interventions have been explained in detail. Inhibition of ABC transporters, cell signaling pathways associated with CSCs, and epigenetic modification offers promising results in this regard. TNBC progression, invasion, metastasis and recurrence can also be inhibited by blocking multiple cell signaling pathways, targeting specific receptors/epigenetic targets, disrupting bioenergetics and generating reactive oxygen species (ROS).

The role of NF-κB in breast cancer initiation, growth, metastasis, and resistance to chemotherapy

Breast cancer (BC) is the second most fatal disease and is the prime cause of cancer allied female deaths. BC is caused by aberrant tumor suppressor genes and oncogenes regulated by transcription factors (TFs) like NF-κB. NF-κB is a pro-inflammatory TF that crucially alters the expressions of various genes associated with inflammation, cell progression, metastasis, and apoptosis and modulates a network of genes that underlie tumorigenesis. Herein, we focus on NF-κB signaling pathways, its regulators, and the rationale for targeting NF-κB. This review also includes TFs that maintain NF-κB crosstalk and their roles in promoting angiogenesis and metastasis. In addition, we discuss the importance of combination therapies, resistance to treatment, and potential novel therapeutic strategies including nanomedicine that targets NF-κB.

Exosome-Mediated miR-4792 Transfer Promotes Bladder Cancer Cell Proliferation via Enhanced FOXC1/c-Myc Signaling and Warburg Effect

Bladder cancer is the second-most common malignancy in the urogenital system and the most common in men. However, our understanding of the driving mechanisms of bladder cancer remains incomplete. The forkhead box (FOX) family of transcription factors is implicated in urogenital development and bladder malignancies. Many exosomal microRNAs have been identified as regulators and mediators of the expression of FOX, including the expression of FOXC1. miR-4792 has been known as a tumor miRNA suppressor. However, the function of miR-4792/FOXC1 signaling in bladder cancer development remains unknown. Here, we studied the role of miR-4792/FOXC1 signaling in bladder cancer by using multiple bladder cancer cell lines and bladder cancer mouse models through in vitro and in vivo approaches. We showed that FOXC1 is highly expressed in multiple bladder cancer cell lines and bladder tumor tissues. The knockdown of FOXC1 expression in bladder cancer cell lines decreases c-Myc expression levels, retards cell growth, and reduces aerobic glycolysis (also known as the Warburg effect) and lactic acid content. By contrast, the overexpression of FOXC1 elicits the opposite effects. FOXC1-downregulated bladder cancer cells form significantly smaller tumors in vivo. The inhibition of c-Myc reverses the effects of FOXC1 overexpression and leads to reduced cell proliferation, aerobic glycolysis, and lactic acid content. miR-4792 expression is downregulated in bladder tumor tissues. miR-4792 exposure to bladder cancer cells reduces the expression levels of FOXC1 and c-Myc, slows down cell growth, and decreases aerobic glycolysis and lactic acid content. However, the enhanced miR-4792 expression elicits opposite effects. These findings provided the first evidence that the exosome-mediated delivery of miR-4792 could play an important role in bladder cancer development through the downregulation of FOXC1 and c-Myc, which further inhibited aerobic glycolysis and lactic acid content.

Therapeutically Targeting Cancers That Overexpress FOXC1: A Transcriptional Driver of Cell Plasticity, Partial EMT, and Cancer Metastasis

Metastasis accounts for more than 90% of cancer related mortality, thus the most pressing need in the field of oncology today is the ability to accurately predict future onset of metastatic disease, ideally at the time of initial diagnosis. As opposed to current practice, what would be desirable is that prognostic, biomarker-based detection of metastatic propensity and heightened risk of cancer recurrence be performed long before overt metastasis has set in. Without such timely information it will be impossible to formulate a rational therapeutic treatment plan to favorably alter the trajectory of disease progression. In order to help inform rational selection of targeted therapeutics, any recurrence/metastasis risk prediction strategy must occur with the paired identification of novel prognostic biomarkers and their underlying molecular regulatory mechanisms that help drive cancer recurrence/metastasis (i.e. recurrence biomarkers). Traditional clinical factors alone (such as TNM staging criteria) are no longer adequately prognostic for this purpose in the current molecular era. FOXC1 is a pivotal transcription factor that has been functionally implicated to drive cancer metastasis and has been demonstrated to be an independent predictor of heightened metastatic risk, at the time of initial diagnosis. In this review, we present our viewpoints on the master regulatory role that FOXC1 plays in mediating cancer stem cell traits that include cellular plasticity, partial EMT, treatment resistance, cancer invasion and cancer migration during cancer progression and metastasis. We also highlight potential therapeutic strategies to target cancers that are, or have evolved to become, “transcriptionally addicted” to FOXC1. The potential role of FOXC1 expression status in predicting the efficacy of these identified therapeutic approaches merits evaluation in clinical trials.

The circular RNA circCPE regulates myoblast development by sponging miR-138

Background

Skeletal muscle development, a long-term and complex process, is controlled by a set of the myogenic genes. Circular RNAs (circRNAs), a class of noncoding RNA, have been shown to regulate various biological processes. Recent studies indicate circRNAs may be involved in myogenesis, but the role and regulatory mechanism of circRNAs in myogenesis is largely unknown. In the present study, circCPE was firstly found to promote the bovine myoblast proliferation and inhibit cell apoptosis and differentiation by influencing the expression of FOXC1 in a miR138-mediated manner. And in vivo experiments revealed that overexpression of circCPE attenuates skeletal muscle regeneration.

Results

We identified a novel circular RNA circCPE by analyzing circRNAs sequencing data of bovine muscle tissue. Sequencing verification, RNase R treatment and Actinomycin D treatment confirmed the circular nature of circCPE in bovine muscle. Functional assays showed that overexpression of circCPE could inhibit bovine myoblast apoptosis and differentiation, as well as facilitate cell proliferation. Moreover, in vivo experiments revealed that overexpression of circCPE attenuates skeletal muscle regeneration. In consideration of circRNA action as miRNAs sponge, we found that circCPE harbors miR-138 binding sites and absorbed miR-138. Mechanistically, the rescue experiments showed that the overexpression of circCPE can counteract the inhibitory effect of miR-138 on the cell proliferation and the accelerated effects on the differentiation and apoptosis. Subsequently, we found that circCPE sequester the inhibitory effect of miR-138 on FOXC1 so as to involve in myogenesis.

Conclusions

Collectively, we constructed a novel circCPE/miR-138/FOXC1 regulatory network in bovine myogenesis, which further provide stronger evidence that circRNA involved in muscle development acting as miRNA sponge.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00618-7.

Knockdown of HCG18 Inhibits Cell Viability, Migration and Invasion in Pediatric Osteosarcoma by Targeting miR-188-5p/FOXC1 Axis

Understanding the underlying mechanisms of pediatric osteosarcoma (OS) migration and invasion is important for prognosis and treatment. We tried to measure the expression of long non-coding RNA HLA complex group 18 (HCG18) in OS and reveal its function in the malignant behaviors of OS cells. This study detected the expression of HCG18, miR-188-5p and forkhead box C1 (FOXC1) in OS tissues and cell lines by quantitative real-time PCR (qRT-PCR). The relevance between miR-188-5p and HCG18 or FOXC1 was affirmed by dual-luciferase reporter (DLR) assay. Cell viability was analyzed by MTT assay. Transwell assay was utilized to test cell invasion and migration. FOXC1 protein expression was detected by western blot. HCG18 expression was elevated in OS tissues, and enhanced HCG18 expression was related to metastasis. HCG18 silencing repressed the viability, migration and invasion of OS cells. Moreover, HCG18 interacted with miR-188-5p. MiR-188-5p up-regulation repressed cell viability, invasion and migration in OS cells. FOXC1, a known target of miR-188-5p, was negatively modulated by miR-188-5p. Furthermore, miR-188-5p inhibition or FOXC1 over-expression partially abolished the reduced of cell viability, invasion and migration mediated by HCG18 silencing in OS cell lines. This study revealed that HCG18 knockdown repressed the viability, invasion and migration of OS cells by targeting miR-188-5p and regulating FOXC1 expression. Thus, HCG18/ miR-188-5p/FOX may be a hopeful target for OS therapy.

The Synergistic Effects of Pyrotinib Combined With Adriamycin on HER2-Positive Breast Cancer

Pyrotinib (PYR) is a pan-HER kinase inhibitor that inhibits signaling via the RAS/RAF/MEK/MAPK and PI3K/AKT pathways. In this study, we aimed to investigate the antitumor efficacy of pyrotinib combined with adriamycin (ADM) and explore its mechanisms on HER2⁺ breast cancer. We investigated the effects of PYR and ADM on breast cancer in vitro and in vivo. MTT assay, Wound-healing, and transwell invasion assays were used to determine the effects of PYR, ADM or PYR combined with ADM on cell proliferation, migration, and invasion of SK-BR-3 and AU565 cells in vitro. Cell apoptosis and cycle were detected through flow cytometry. In vivo, xenograft models were established to test the effect of PYR, ADM, or the combined therapy on the nude mice. Western blotting was performed to assess the expression of Akt, p-Akt, p-65, p-p65, and FOXC1. The results indicated that PYR and ADM significantly inhibited the proliferation, migration, and invasion of SK-BR-3 and AU565 cells, and the inhibitory rate of the combination group was higher than each monotherapy group. PYR induced G1 phase cell-cycle arrest, while ADM induced G2 phase arrest, while the combination group induced G2 phase arrest. The combined treatment showed synergistic anticancer activities. Moreover, PYR significantly downregulated the expression of p-Akt, p-p65, and FOXC1. In clinical settings, PYR also exerts satisfactory efficacy against breast cancer. These findings suggest that the combination of PYR and ADM shows synergistic effects both in vitro and in vivo. PYR suppresses the proliferation, migration, and invasion of breast cancers through down-regulation of the Akt/p65/FOXC1 pathway.

Defining super-enhancer landscape in triple-negative breast cancer by multiomic profiling

Breast cancer is a heterogeneous disease, affecting over 3.5 million women worldwide, yet the functional role of cis-regulatory elements including super-enhancers in different breast cancer subtypes remains poorly characterized. Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis. Here we apply integrated epigenomic and transcriptomic profiling to uncover super-enhancer heterogeneity between breast cancer subtypes, and provide clinically relevant biological insights towards TNBC. Using CRISPR/Cas9-mediated gene editing, we identify genes that are specifically regulated by TNBC-specific super-enhancers, including FOXC1 and MET, thereby unveiling a mechanism for specific overexpression of the key oncogenes in TNBC. We also identify ANLN as a TNBC-specific gene regulated by super-enhancer. Our studies reveal a TNBC-specific epigenomic landscape, contributing to the dysregulated oncogene expression in breast tumorigenesis.

Prognostic significance of hedgehog signaling network-related gene expression in breast cancer patients

Breast cancer continues to be a serious public health problem. The role of the hedgehog pathway in normal development of the mammary gland as well as in carcinogenesis and progression of breast cancer is the subject of intense investigation, revealing functional interactions with cell surface heparan sulfate. Nevertheless, its influence on breast cancer prognosis, and its relation to specific sulfation motifs in heparan sulfate have only been poorly studied in large patient cohorts. Using the public database KMplotter that includes gene expression and survival data of 3951 patients, we found that the higher expression of SHH, HHAT, PTCH1, GLI1, GLI2, and GLI3 positively influences breast cancer prognosis. Stratifying patients according to the expression of hormone receptors, histological grade, lymph node metastasis, and systemic therapy, we observed that GLI1, GLI2, and GLI3 expression, as well as co-expression of SHH and ELP1 were associated with worse relapse-free survival in patients with HER2-positive tumors. Moreover, GLI1 expression in progesterone receptor-negative tumors and GLI3 expression in grade 3 tumors correlated with poor prognosis. SHH, in a panel of cell lines representing different breast cancer subtypes, and HHAT, PTCH1, GLI1, GLI2, and GLI3 were mostly expressed in cell lines classified as HER2-positive and basal-like. Expression of SHH, HHAT, GLI2, and GLI3 was differentially affected by overexpression of the heparan sulfate sulfotransferases HS2ST1 and HS3ST2 in vitro. Although high HS2ST1 expression was associated with poor prognosis in KMplotter analysis, high levels of HS3ST2 were associated with a good prognosis, except for ER-positive breast cancer. We suggest the GLI transcription factors as possible markers for the diagnosis, treatment, and prognosis of breast cancer especially in HER2-positive tumors, but also in progesterone receptor-negative and grade-3 tumors. The pathway interaction and prognostic impact of specific heparan sulfate sulfotransferases provide novel perspectives regarding a therapeutical targeting of the hedgehog pathway in breast cancer.

Positive Cross-Talk Between CXC Chemokine Receptor 4 (CXCR4) and Epidermal Growth Factor Receptor (EGFR) Promotes Gastric Cancer Metastasis via the Nuclear Factor kappa B (NF-kB)-Dependent Pathway

BACKGROUND Previous studies have established cross-talk between CXC chemokine receptor 4 (CXCR4) and epidermal growth factor receptor (EGFR) in gastric cancer, however, the effect of dual CXCR4/EGFR tumor status on patient survival and mechanisms regulating expression has yet to be investigated. MATERIAL AND METHODS A total of 56 gastric cancer patients were recruited to reveal the relationship between CXCR4 and EGFR expression, and the clinic-pathological features of samples were investigated by immunohistochemical staining. Two gastric cancer cell lines were treated with CXCL12 or EGF, and expression levels of CXCR4 and EGFR were detected by reverse-transcription-polymerase chain reaction and western blotting. Cells were treated with an NF-kappaB pathway inhibitor to investigate its role in the regulation of CXCL12 or EGF-mediated CXCR4 and EGFR expression and migration ability. RESULTS The results show that CXCL12 upregulated CXCR4 and EGFR. Similarly, EGF could induce the expression of CXCR4 and contribute to gastric cancer cell metastasis. In addition, both CXCL12 and EGF could induce the activation of IKKalphaß and P65. Conversely, suppression of the NF-kappaB pathway remarkably decreased the expression of CXCR4/EGFR and migration ability induced by EGF or CXCL12. Furthermore, a significantly positive correlation between CXCR4 and EGFR expression was observed in gastric cancer patient tissues (r=0.372, P=0.005). Samples expressing both receptors had significantly poorer patient prognosis than other patient groups (P=0.002). CONCLUSIONS Our results showed that the CXCL12/CXCR4 and EGF/EGFR axis can regulate the expression of each other through the NF-kappaB pathway to promote metastasis. These data suggested that simultaneous inhibition of EGFR and CXCR4 may be a potential therapeutic strategy in gastric cancer.

Prognostic and clinicopathological values of tissue expression of MFAP5 and ITM2A in triple-negative breast cancer: an immunohistochemical study

Introduction

Triple-negative breast cancer (TNBC) is a markedly aggressive molecular subtype of breast cancer; there is an urgent need to clarify the molecular mechanisms underlying the progression and metastases of BLBC, in order to find a novel targeted therapy. Microfibrillar-associated protein 5 (MFAP5) plays an essential role in the regulation of cell behaviour and survival. Integral membrane protein 2A (ITM2A) is a type II transmembrane protein, which is a member of a family of autophagy related proteins.

The aim of this study was to assess the expression of MFAP5 and ITM2A proteins in tissues of BLBC using immunohistochemistry, in order to correlate the expression with clinicopathological and prognostic parameters of such aggressive cancer.

Material and methods

The present study included sections from archived paraffin blocks retrieved from 120 patients with TNBC. We collected cases from three years, i.e. from 2016 to 2019. We assessed expression of MFAP5 and ITM2A using immunohistochemistry.

Results

High expression of MFAP5 and low expression of ITM2A was associated with advanced stage (p = 0.007), higher grade of tumour (p = 0.005 and p = 0.004, respectively), the presence of lymph nodes metastases (p < 0.001 and p = 0.002, respectively), lower three-year RFS rate (p < 0.001 and p = 0.016, respectively), and lower three-year OS rate (p < 0.001).

Conclusions

MFAP5 and ITM2A are novel prognostic biomarkers for breast cancer and might be considered as promising therapeutic targets for patients with breast cancer, particularly TNBC molecular subtype, in the future.

Suppressing migration and invasion of H1299 lung cancer cells by honokiol through disrupting expression of an HDAC6-mediated matrix metalloproteinase 9

Metastasis is the crucial mechanism to cause high mortality in lung cancer. Degradation of extracellular matrix (ECM) by proteolytic enzymes, especially matrix metalloproteinases (MMPs), is a key process for promoting cancer cell migration and invasion. Therefore, targeting MMPs might be a strategy for lung cancer metastasis suppression. Honokiol, a biological active component of Magnolia officinalis, has been indicated to suppress lung cancer tumorigenesis through epigenetic regulation. However, the regulation of MMPs‐mediated migration and invasion by honokiol through epigenetic regulation in lung cancer is still a mystery. In the present study, the migration and invasion ability of H1299 lung cancer was suppressed by noncytotoxic concentrations of honokiol treatment. The proteolytic activity of MMP‐9, rather than MMP‐2, was inhibited in honokiol‐treated H1299 cells. Honokiol‐inhibited MMP‐9 expression was through promoting MMP‐9 protein degradation rather than suppressing transcription mechanism. Furthermore, the expression of specific histone deacetylases 6 (HDAC6) substrate, acetyl‐α‐tubulin, was accumulated after honokiol incubation. The disassociation of MMP‐9 with hyper‐acetylated heat shock protein 90 (Hsp90) was observed resulting in MMP‐9 degradation after honokiol treatment. Meanwhile, honokiol‐suppressed MMP‐9 expression and invasion ability of H1299 lung cancer cells was rescued by HDAC6 overexpression. Accordingly, the results suggested that the suppression of migration and invasion activities by honokiol was through inhibiting HDAC6‐mediated Hsp90/MMP‐9 interaction and followed by MMP‐9 degradation in lung cancer.

The Hedgehog Signaling Pathway: A Viable Target in Breast Cancer?

The hedgehog (Hh) pathway plays a key role in embryonic development and stem cell programs. Deregulation of the Hh pathway is a key driver of basal cell carcinoma, and therapeutic targeting led to approval of Hh inhibitor, vismodegib, in the management of this cancer. The Hh pathway is implicated in other malignancies including hormone receptor (HR+) positive and triple negative breast cancer (TNBC). Hh signaling, which is activated in human mammary stem cells, results in activation of glioma-associated oncogene (GLI) transcription factors. High GLI1 expression correlates with worse outcomes in breast cancer. Non-canonical GLI1 activation is one mechanism by which estrogen exposure promotes breast cancer stem cell proliferation and epithelial–mesenchymal transition. Tamoxifen resistant cell lines show aberrant activation of Hh signaling, and knockdown of Hh pathway inhibited growth of tamoxifen resistant cells. As in other cancers Hh signaling is activated by the PI3K/AKT pathway in these endocrine resistant cell lines. Hh pathway activation has also been reported to mediate chemotherapy resistance in TNBC via various mechanisms including paracrine signaling to tumor micro-environment and selective proliferation of cancer stem cells. Co-activation of Hh and Wnt signaling pathways is a poor prognostic marker in TNBC. Early phase clinical trials are evaluating the combination of smoothened (SMO) inhibitors and chemotherapy in TNBC. In addition to SMO inhibitors like vismodegib and sonidegib, which are in clinical use for basal cell carcinoma, GLI1 inhibitors like GANT58 and GANT61 are in preclinical drug development and might be an effective mechanism to overcome drug resistance in breast cancer. Gene signatures predictive of Hh pathway activation could enrich for patients likely to respond to these agents.

Integrative analyses of triple negative dysregulated transcripts compared with non-triple negative tumors and their functional and molecular interactions

Triple-negative (TN) tumors are a subtype of breast cancer with aggressive behaviors and limited targeted therapies. Microarray studies were not concerned with interactions and functional relations of dysregulated transcripts. Here, we aimed to conduct integrative strategy to analyze gene and miRNA available microarray data as well as bioinformatic analyses to catch a more inclusive picture of pivotal dysregulated transcripts and their interactions in TN tumors. Several online datasets and offline bioinformatic tools were used to detect differentially expressed (DE) transcripts, both protein and nonprotein coding, in TN compared with non-TN tumors and their functional and molecular interactions. Sixteen upregulated and 58 downregulated genes with a log fold change higher or equal to | 2 | were identified, including nine transcription factors. Coexpression network revealed EN1 as a hub gene, moreover Kaplan-Meier plotter survival analysis indicated that it was an appropriate prognostic marker for TN patients with breast cancer. Functional annotation analysis of protein-protein interaction network showed FOXM1 as an upexpressed and ESR1 as a downexpressed hub genes are suitable targets as far as antitumor protein therapy is concerned in TN breast cancers. The consensus analysis of two microRNA datasets revealed seven DE miRNAs. The gene-transcriptional factor (TF)-miRNA network revealed mir-135b and mir-29b are the hub nodes and involved in feedback loops with GATA3. This study suggests that dysregulated TFs and miRNAs have pivotal roles in regulation of TN oncotranscriptomic profile and might become both biomarkers and therapeutic targets.

MFAP5 promotes basal-like breast cancer progression by activating the EMT program

Purpose

Human basal-like breast cancer (BLBC) is an aggressive malignancy with poor prognosis. Since most current treatments are ineffective, there is an urgent need to identify therapeutic targets for BLBC. Microfibrillar-associated protein 5 (MFAP5) plays an important role in the integration of elastic microfibers and the regulation of endothelial cell behaviors. We previously demonstrated that MFAP5 was significantly overexpressed in BLBC tissues and associated with poor metastasis-free survival of patients with BLBC. However, the detailed role of MFAP5 in BLBC is unclear. Thereby, the current study aimed to investigate the underlying function of MFAP5 in BLBC.

Method

Functional analyses were conducted for the role of MFAP5 in BLBC in vitro and in vivo.

Results

Overexpression of MFAP5 resulted in a significant increase in the proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) markers in BLBC in vitro and in vivo. In addition, other metastasis animal models by tail intravenous injection of BT20 cells further confirmed that MFAP5 overexpression promoted BLBC proliferation and BT20 cells metastasis. We found that the TGF-β or Notch inhibitor significantly reversed the tumorigenicity and metastasis of MFAP5-induced BLBC cells.

Conclusion

Our findings suggest that MFAP5 may promote EMT in BLBC metastasis via the TGF-β/Notch pathway.

Electronic supplementary material

The online version of this article (10.1186/s13578-019-0284-0) contains supplementary material, which is available to authorized users.

The Diverse Consequences of FOXC1 Deregulation in Cancer

Forkhead box C1 (FOXC1) is a transcription factor with essential roles in mesenchymal lineage specification and organ development during normal embryogenesis. In keeping with these developmental properties, mutations that impair the activity of FOXC1 result in the heritable Axenfeld-Rieger Syndrome and other congenital disorders. Crucially, gain of FOXC1 function is emerging as a recurrent feature of malignancy; FOXC1 overexpression is now documented in more than 16 cancer types, often in association with an unfavorable prognosis. This review explores current evidence for FOXC1 deregulation in cancer and the putative mechanisms by which FOXC1 confers its oncogenic effects.

Restoration of GATA4 expression impedes breast cancer progression by transcriptional repression of ReLA and inhibition of NF-κB signaling

There are increasing reports of aberrant expression of GATA4, correlated with oncogenesis and malignant progression in some solid tumors, but whether GATA4 functions as an oncogenic driver or a tumor suppressor in carcinogenesis remains controversial. Because the role and mechanism of GATA4 in breast cancer (BrCa) remain poorly understood, we focused on the expression of GATA4 in BrCa cell lines and tissues and its mechanism in breast oncogenesis. Semiquantitative real-time polymerase chain reaction (RT-PCR), quantitative RT-PCR, Western blot analysis, and immunohistochemistry were used to detect expression of GATA4 in BrCa cell lines and adjacent breast tissues. Methylation statuses of the GATA4 promoter were studied using methylation-specific PCR in BrCa cell lines.The effects of GATA4 on proliferation, invasion, and cell cycle were also analyzed. Compared with adjacent breast tissue, GATA4 expression in BrCa tissue and cell lines was obviously lower and low expression levels of GATA4 predicted poor outcome. Methylation of GATA4 occurred in almost all of BrCa cell lines . GATA4 overexpression decreased viability, invasion, migration, and epithelial-to-mesenchymal transition of MB-231 and BT549 cells, and markedly induced cell cycle arrest and apoptosis. Exogenous expression GATA4 accompanied a significant alteration of MMP2, MMP3, E-cadherin, and N-cadherin expression and induction of the caspase-8 pathway. Moreover, GATA4 could directly repress RelA (p65) transcription, reduce the nuclear phosphorylation-p65 and upregulate inhibitor kappa B expression. Altogether, GATA4 plays a tumor-suppressive role via repression of NF-κB signaling in BrCa cells. Our findings suggest that GATA4 is a potential prognostic biomarker and gene therapeutic target for human BrCa.

[Activation of nuclear factor-κB subunit p50/p65 enhances gefitinib resistance of lung adenocarcinoma H1650 cell line]

OBJECTIVE

To explore the intrinsic connection between activation of classical nuclear factor-κB (NF-κB) pathway and gefitinib resistance in human lung adenocarcinoma H1650 cells.

METHODS

Human lung adenocarcinoma H1650 cells were exposed to gefitinib continuously for 60 days to obtain resistant H1650 cells. The expressions of P-IκBα, P-p50 and P-p65 in the cytoplasm or nuclei were detected using Western blotting in human lung adenocarcinoma HCC827 cells, parental H1650 cells and gefitinib-resistant H1650 cells. The effects of gefitinib alone or in combination with PDTC on the survival rate and expressions of NF-κB P-p50 and P-p65 were compared among the 3 cell lines.

RESULTS

Gefitinib-resistant H1650 cells showed increased cytoplasmic and nuclear P-IκBα expressions. The expressions of P-p50 and P-p65 differed significantly among the 3 cell line, decreasing in the order of resistant H1650 cells, parental H1650 cells, and gefitinib sensitive HCC827 cell lines (P<0.05 or 0.01). Treatment with gefitinib alone resulted in a significantly lower cell inhibition rate in resistant H1650 cells than in the parental H1650 cells (P<0.05) and HCC827 cells (P<0.01). The resistant H1650 cells had a significantly higher expression of P-p50 and P-p65 than other two cell lines (P<0.05). In both the resistant and parental H1650 cells, gefitinib significantly lowered P-p50 and P-p65 expressions (P<0.05 or 0.01), and the combined treatment with gefitinib and PDTC significantly decreased the cell survival rate and further lowered the cytoplasmic and nuclear expressions of P-p50 and P-p65 (P<0.01 or 0.01).

CONCLUSION

The activation of classical NF-κB pathway is a key factor contributing to transformation of the parental H1650 cells into gefitinib-resistant cells. Gefitinib combined with PDTC can inhibit P-IκBα production and NF-κB P-p50 and P-p65 activation to suppress the survival of residual H1650 cells and the generation of gefitinib-resistant cells.

FOXC1, the new player in the cancer sandbox

In recent years, rapidly accumulating evidence implicates forkhead box C1 (FOXC1) in cancer, especially in studies of basal-like breast cancer (BLBC). Other studies have followed suit, demonstrating that FOXC1 is not only a major player in this breast cancer subtype, but also in hepatocellular carcinoma (HCC), endometrial cancer, Hodgkin's lymphoma (HL), and non-Hodgkin's lymphoma (NHL). The FOXC1 gene encodes a transcription factor that is crucial to mesodermal, neural crest, and ocular development, and mutations found in FOXC1 have been found to cause dominantly inherited Axenfeld-Rieger Syndrome (ARS). Interestingly, while FOXC1 missense mutations that are associated with ARS usually reduce gene activity, increased FOXC1 function now appears to be often linked to more aggressive cancer phenotypes in BLBC, HCC, HL, and NHL. This review discusses not only the role of FOXC1 in cancer cell progression, proliferation, differentiation, and metastasis, but also the underlying mechanisms of how FOXC1 can contribute to aggressive cancer phenotypes.

The suppression of DUSP5 expression correlates with paclitaxel resistance and poor prognosis in basal-like breast cancer

Basal-like breast cancer (BLBC) is resistant to endocrinotherapy and targeted therapy and new molecular therapies are needed for BLBC. In this study, we evaluated the role of DUSP1 and DUSP5, negative regulators of mitogen-activated protein kinase pathway, in the aggressiveness of BLBC. MDA-MB-231 cells were given paclitaxel (PTX) treatment and subsequently PTX resistant cell clones were established. Microarray analysis, real-time quantitative reverse transcription PCR (qRT-PCR), and online analysis of large cohorts of breast cancer patients were performed. The PTX resistant cells showed stronger cell proliferation ability by exhibiting the upregulation of CENPF, CDC6, MCM3, CLSPN and SMC1A expression. Furthermore, DUSP1 and DUSP5 expression was significantly downregulated in PTX resistant cells. In addition, in large breast cancer patients' database, both DUSP1 and DUSP5 correlated negatively with higher histological grade. DUSP1 low expression was obvious in HER2 positive and basal like while DUSP5 low expression was peculiar for basal like compared with other subtypes. Remarkably, low expression of DUSP5, but not DUSP1, was significantly correlated with poor survival of BLBC patients. In conclusion, our data suggest that loss of DUSP5 expression results in PTX resistance and tumor progression, providing a rationale for a therapeutic agent that restores DUSP5 in BLBC.

FOXC1 in cancer development and therapy: deciphering its emerging and divergent roles

Forkhead box C1 (FOXC1) is an essential member of the forkhead box transcription factors and has been highlighted as an important transcriptional regulator of crucial proteins associated with a wide variety of carcinomas. FOXC1 regulates tumor-associated genes and is regulated by multiple pathways that control its mRNA expression and protein activity. Aberrant FOXC1 expression is involved in diverse tumorigenic processes, such as abnormal cell proliferation, cancer stem cell maintenance, cancer migration, and angiogenesis. Herein, we review the correlation between the expression of FOXC1 and tumor behaviors. We also summarize the mechanisms of the regulation of FOXC1 expression and activity in physiological and pathological conditions. In particular, we focus on the pathological processes of cancer targeted by FOXC1 and discuss whether FOXC1 is good or detrimental during tumor progression. Moreover, FOXC1 is highlighted as a clinical biomarker for diagnosis or prognosis in various human cancers. The information reviewed here should assist in experimental designs and emphasize the potential of FOXC1 as a therapeutic target for cancer.