c-Met activation through a novel pathway involving osteopontin mediates oncogenesis by the transcription factor LSF

TFCP2 as a therapeutic nexus: unveiling molecular signatures in cancer

Tumor suppressor genes and proto-oncogenes comprise most of the complex genomic landscape associated with cancer, with a minimal number of genes exhibiting dual-context-dependent functions. The transcription factor cellular promoter 2 (TFCP2), a pivotal transcription factor encoded by the alpha globin transcription factor CP2 gene, is a constituent of the TFCP2/grainyhead family of transcription factors. While grainyhead members have been extensively studied for their crucial roles in developmental processes, embryogenesis, and multiple cancers, the TFCP2 subfamily has been relatively less explored. The molecular mechanisms underlying TFCP2's involvement in carcinogenesis are still unclear even though it is a desirable target for cancer treatment and a therapeutic marker. This comprehensive literature review summarizes the molecular functions of TFCP2, emphasizing its involvement in cancer pathophysiology, particularly in the epithelial-mesenchymal transition and metastasis. It highlights TFCP2's critical function as a regulatory target and explores its potential as a prognostic marker for survival and inflammation in carcinomas. Its ambiguous association with carcinomas underlines the urgent need for an in-depth understanding to facilitate the development of more efficacious targeted therapeutic modality and diagnostic tools. This study aims to elucidate the multifaceted effects of TFCP2 regulation, through a comprehensive integration of the existing knowledge in cancer therapeutics. Furthermore, the clinical relevance and the inherent challenges encountered in investigating its intricate role in cancer pathogenesis have been discussed in this review.

Dysregulation of miRISC Regulatory Network Promotes Hepatocellular Carcinoma by Targeting PI3K/Akt Signaling Pathway

Hepatocellular carcinoma (HCC) remains the third leading malignancy worldwide, causing high mortality in adults and children. The neuropathology-associated gene AEG-1 functions as a scaffold protein to correctly assemble the RNA-induced silencing complex (RISC) and optimize or increase its activity. The overexpression of oncogenic miRNAs periodically degrades the target tumor suppressor genes. Oncogenic miR-221 plays a seminal role in the carcinogenesis of HCC. Hence, the exact molecular and biological functions of the oncogene clusters miR-221/AEG-1 axis have not yet been examined widely in HCC. Here, we explored the expression of both miR-221 and AEG-1 and their target/associate genes by qRT-PCR and western blot. In addition, the role of the miR-221/AEG-1 axis was studied in the HCC by flow cytometry analysis. The expression level of the AEG-1 did not change in the miR-221 mimic, and miR-221-transfected HCC cells, on the other hand, decreased the miR-221 expression in AEG-1 siRNA-transfected HCC cells. The miR-221/AEG-1 axis silencing induces apoptosis and G2/M phase arrest and inhibits cellular proliferation and angiogenesis by upregulating p57, p53, RB, and PTEN and downregulating LSF, LC3A, Bcl-2, OPN, MMP9, PI3K, and Akt in HCC cells.

HGF/c-Met: A Key Promoter in Liver Regeneration

Hepatocyte growth factor (HGF) is a peptide-containing multifunctional cytokine that acts on various epithelial cells to regulate cell growth, movement and morphogenesis, and tissue regeneration of injured organs. HGF is sequestered by heparin-like protein in its inactive form and is widespread in the extracellular matrix of most tissues. When the liver loses its average mass, volume, or physiological and biochemical functions due to various reasons, HGF binds to its specific receptor c-Met (cellular mesenchymal-epithelial transition) and transmits the signals into the cells, and triggers the intrinsic kinase activity of c-Met. The downstream cascades of HGF/c-Met include JAK/STAT3, PI3K/Akt/NF-κB, and Ras/Raf pathways, affecting cell proliferation, growth, and survival. HGF has important clinical significance for liver fibrosis, hepatocyte regeneration after inflammation, and liver regeneration after transplantation. And the development of HGF as a biological drug for regenerative therapy of diseases, that is, using recombinant human HGF protein to treat disorders in clinical trials, is underway. This review summarizes the recent findings of the HGF/c-Met signaling functions in liver regeneration.

Regulation on tumor metastasis by Raf kinase inhibitory protein: New insight with reactive oxygen species signaling

Targeted therapy aiming at the metastatic signal pathway, such as that triggered by receptor tyrosine kinase (RTK), for the prevention of tumor progression is promising. However, RTK-based targeted therapy frequently suffered from drug resistance due to the co-expression of multiple growth factor receptors that may raise compensatory secondary signaling and acquired mutations after treatment. One alternative strategy is to manipulate the common negative regulators of the RTK signaling. Among them, Raf kinase inhibitory protein (RKIP) is highlighted and focused on this review. RKIP can associate with Raf-1, thus suppressing the downstream mitogen-activated protein kinase (MAPK) cascade. RKIP also negatively regulates other metastatic signal molecules including NF-κB, STAT3, and NOTCH1. In general, RKIP achieves this task via associating and blocking the activity of the critical molecules on upstream of the aforementioned pathways. One novel RKIP-related signaling involves reactive oxygen species (ROS). In our recent report, we found that PKCδ-mediated ROS generation may interfere with the association of RKIP with heat shock protein 60 (HSP60)/MAPK complex via oxidation of HSP60 triggered by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate. The departure of RKIP may impact the downstream MAPK in two aspects. One is to trigger the Mt→cytosol translocation of HSP60 coupled with MAPKs. The other is to change the conformation of HSP60, favoring more efficient activation of the associated MAPK by upstream kinases in cytosol. It is worthy of investigating whether various RTKs capable of generating ROS can drive metastatic signaling via affecting RKIP in the same manner.

The role of SPP1 as a prognostic biomarker and therapeutic target in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies and has a low 5-year survival rate. Mounting evidence suggests that oral potentially malignant disorders, such as oral leukoplakia (OLK), may progress to HNSCC. Given that OLK and HNSCC are often insidious and asymptomatic, the identification of markers of OLK malignant transformation and therapeutic targets in HNSCC is critical. Using various online tools and publicly available gene expression datasets, the secreted phosphoprotein 1 gene (SPP1) was identified as a significant differentially expressed gene among OLK, HNSCC, and non-cancerous tissues. SPP1 mRNA levels were elevated in HNSCC tissues and were associated with cancer stage, tumor grade, and human papillomavirus infection status. High SPP1 mRNA levels were correlated with poor overall survival of HNSCC patients. In contrast, SPP1 mutations were not significantly associated with overall survival, although their frequency in HNSCC was very low (0.6%). Furthermore, SPP1 expression levels in HNSCC were positively correlated with the infiltration of CD4⁺ cells, macrophages, neutrophils, and dendritic cells. The study results suggest that SPP1 may represent a diagnostic and prognostic biomarker, as well as a potential therapeutic target in HNSCC.

Astrocyte elevated gene-1 (AEG-1): A key driver of hepatocellular carcinoma (HCC)

An array of human cancers, including hepatocellular carcinoma (HCC), overexpress the oncogene Astrocyte elevated gene-1 (AEG-1). It is now firmly established that AEG-1 is a key driver of carcinogenesis, and enhanced expression of AEG-1 is a marker of poor prognosis in cancer patients. In-depth studies have revealed that AEG-1 positively regulates different hallmarks of HCC progression including growth and proliferation, angiogenesis, invasion, migration, metastasis and resistance to therapeutic intervention. By interacting with a plethora of proteins as well as mRNAs, AEG-1 regulates gene expression at transcriptional, post-transcriptional, and translational levels, and modulates numerous pro-tumorigenic and tumor-suppressive signal transduction pathways. Even though extensive research over the last two decades using various in vitro and in vivo models has established the pivotal role of AEG-1 in HCC, effective targeting of AEG-1 as a therapeutic intervention for HCC is yet to be achieved in the clinic. Targeted delivery of AEG-1 small interfering ribonucleic acid (siRNA) has demonstrated desired therapeutic effects in mouse models of HCC. Peptidomimetic inhibitors based on protein-protein interaction studies has also been developed recently. Continuous unraveling of novel mechanisms in the regulation of HCC by AEG-1 will generate valuable knowledge facilitating development of specific AEG-1 inhibitory strategies. The present review describes the current status of AEG-1 in HCC gleaned from patient-focused and bench-top studies as well as transgenic and knockout mouse models. We also address the challenges that need to be overcome and discuss future perspectives on this exciting molecule to transform it from bench to bedside.

A Feedback Loop Comprising EGF/TGFα Sustains TFCP2-Mediated Breast Cancer Progression

Stemness and epithelial-mesenchymal transition (EMT) are two fundamental characteristics of metastasis that are controlled by diverse regulatory factors, including transcription factors. Compared with other subtypes of breast cancer, basal-type or triple-negative breast cancer (TNBC) has high frequencies of tumor relapse. However, the role of alpha-globin transcription factor CP2 (TFCP2) has not been reported as an oncogenic driver in those breast cancers. Here, we show that TFCP2 is a potent factor essential for EMT, stemness, and metastasis in breast cancer. TFCP2 directly bound promoters of EGF and TGFα to regulate their expression and stimulate autocrine signaling via EGFR. These findings indicate that TFCP2 is a new antimetastatic target and reveal a novel regulatory mechanism in which a positive feedback loop comprising EGF/TGFα and AKT can control malignant breast cancer progression. SIGNIFICANCE: TFCP2 is a new antimetastatic target that controls TNBC progression via a positive feedback loop between EGF/TGFα and the AKT signaling axis.

A subset of epithelioid and spindle cell rhabdomyosarcomas is associated with TFCP2 fusions and common ALK upregulation

Rhabdomyosarcomas with TFCP2 fusions represent an emerging subtype of tumors, initially discovered by RNA-sequencing. We report herein the clinicopathological, transcriptional, and genomic features of a series of 14 cases. Cases were retrospectively and prospectively recruited and studied by immunohistochemistry (MYF4, MYOD1, S100, AE1/E3, ALK), fluorescence in situ hybridization with TFCP2 break-apart probe (n = 10/14), array-comparative genomic hybridization (Agilent), whole RNA-sequencing (Truseq Exome, Illumina), or anchored multiplex PCR-based targeted next-generation sequencing (Archer® FusionPlex® Sarcoma kit). Patient's age ranged between 11 and 86 years, including 5 pediatric cases. Tumors were located in the bone (n = 12/14) and soft tissue (n = 2/14). Most bone tumors invaded surrounding soft tissue. Craniofacial bones were over-represented (n = 8/12). Median survival was 8 months and five patients are currently alive with a median follow-up of 20 months. Most tumors displayed a mixed spindle cell and epithelioid pattern with frequent vesicular nuclei. All tumors expressed keratins and showed a rhabdomyogenic phenotype (defined as expression of MYF4 and/or MYOD1). ALK was overexpressed in all but three cases without underlying ALK fusion on break-apart FISH (n = 5) nor next-generation sequencing (n = 14). ALK upregulation was frequently associated with an internal deletion at genomic level. TFCP2 was fused in 5' either to EWSR1 (n = 6) or FUS (n = 8). EWSR1 was involved in both soft tissue cases. FISH with TFCP2 break-apart probe was positive in all tested cases (n = 8), including one case with unbalanced signal. On array-CGH, all tested tumors displayed complex genetic profiles with genomic indexes ranging from 13 to 107.55 and recurrent CDKN2A deletions. FET-TFCP2 rhabdomyosarcomas clustered together and distinctly from other rhabdomyosarcomas subgroups. Altogether, our data confirm and expand the spectrum of the new family of FET-TFCP2 rhabdomyosarcomas, which are associated with a predilection for the craniofacial bones, an aggressive course, and recurrent pathological features. Their association with ALK overexpression might represent a therapeutic vulnerability.

AEG-1/miR-221 Axis Cooperatively Regulates the Progression of Hepatocellular Carcinoma by Targeting PTEN/PI3K/AKT Signaling Pathway

Hepatocellular carcinoma (HCC) is the third leading malignancy worldwide, causing mortality in children and adults. AEG-1 is functioned as a scaffold protein for the proper assembly of RNA-induced silencing complex (RISC) to optimize or increase its activity. The increased activity of oncogenic miRNAs leads to the degradation of target tumor suppressor genes. miR-221 is an oncogenic miRNA, that plays a seminal role in carcinogenesis regulation of HCC. However, the molecular mechanism and biological functions of the miR-221/AEG-1 axis have not been investigated extensively in HCC. Here, the expression of miR-221/AEG-1 and their target/associate genes was analyzed by qRT-PCR and Western blot. The role of the miR-221/AEG-1 axis in HCC was evaluated by proliferation assay, migration assay, invasion assay, and flow cytometry analysis. The expression level of miR-221 decreased in AEG-1 siRNA transfected HCC cells. On the other hand, there were no significant expression changes of AEG-1 in miR-221 mimic and miR-221 inhibitor transfected HCC cells and inhibition of miR-221/AEG-1 axis decreased cell proliferation, invasion, migration, and angiogenesis and induced apoptosis, cell cycle arrest by upregulating p57, p53, PTEN, and RB and downregulating LSF, MMP9, OPN, Bcl-2, PI3K, AKT, and LC3A in HCC cells. Furthermore, these findings suggest that the miR-221/AEG-1 axis plays a seminal oncogenic role by modulating PTEN/PI3K/AKT signaling pathway in HCC. In conclusion, the miR-221/AEG-1 axis may serve as a potential target for therapeutics, diagnostics, and prognostics of HCC.

circRNA_104075 stimulates YAP-dependent tumorigenesis through the regulation of HNF4a and may serve as a diagnostic marker in hepatocellular carcinoma

Some types of circular RNA (circRNA) are aberrantly expressed in human diseases including hepatocellular carcinoma (HCC). However, its regulation mechanism and diagnostic roles are largely unknown. Here, we identified that circRNA_104075 (circ_104075) was highly expressed in HCC tissues, cell lines and serum. Mechanistically, HNF4a bound to the -1409 to -1401 region of the circ_104075 promoter to stimulate the expression of circ_104075. Moreover, circ_104075 acted as a ceRNA to upregulate YAP expression by absorbing miR-582-3p. Interestingly, an N6-methyladenosine (m6A) motif was identified in the 353-357 region of YAP 3'UTR, and this m6A modification was essential for the interaction between miR-582-3p and YAP 3'UTR. Further, the diagnostic performance of circ_104075 was evaluated. The area under the receiver operating characteristic (AUC-ROC) for circ_104075 was 0.973 with a sensitivity of 96.0% and a specificity of 98.3%. Collectively, we determined that circ_104075 was highly expressed in HCC and elucidated its upstream and downstream regulatory mechanisms. circ_104075 additionally has the potential to serve as a new diagnostic biomarker in HCC. Targeting circ_104075 may provide new strategies in HCC diagnosis and therapy.

Diagnostic and prognostic relevance of CP2c and YY1 expression in hepatocellular carcinoma

Recent studies have demonstrated an oncogenic role of the transcription factor (TF) CP2c in hepatocellular carcinoma (HCC) based on a strong correlation between CP2c expression, tumor grade, and aggressiveness. We recently found that CP2c directly interacts with another TF, YY1, which is also overexpressed in multiple cancers, including HCC. To evaluate if these proteins are co-regulated in carcinogenesis, we analyzed the expression of CP2c and YY1 in HCC (n = 136) tissues and examined the correlation between their expression and clinicopathological characteristics of HCC. Receiver operating characteristic analysis exhibited the validity of CP2c and nuclear YY1 expression as a diagnostic factor in HCC tissues. High expression of CP2c was significantly correlated with patient age, and higher histological grade, American Joint Committee on Cancer (AJCC) stage, and small and large vessel invasion in HCC tissues, whereas high expression of nuclear YY1 was significantly associated with higher AJCC stage and small vessel invasion. In univariate and multivariate analyses, high expression of CP2c was significantly correlated with disease free survival (DFS), indicating that CP2c expression is an independent prognostic factor for DFS in HCC patients. Patients with high expression of both CP2c and nuclear YY1 usually had a shorter median survival time and worse DFS prognosis than other patients, suggesting that combined detection of CP2c and nuclear YY1 is a useful prognostic marker in HCC patients.

TFCP2/TFCP2L1/UBP1 transcription factors in cancer

The TFCP2/Grainyhead family of transcription factors is divided into two distinct subfamilies, one of which includes the Grainyhead-like 1-3 (GRHL1-3) proteins and the other consists of TFCP2 (synonyms: CP2, LSF, LBP-1c), TFCP2L1 (synonyms: CRTR-1, LBP-9) and UBP1 (synonyms: LBP-1a, NF2d9). Transcription factors from the TFCP2/TFCP2L1/UBP1 subfamily are involved in various aspects of cancer development. TFCP2 is a pro-oncogenic factor in hepatocellular carcinoma, pancreatic cancer and breast cancer, may be important in cervical carcinogenesis and in colorectal cancer. TFCP2 can also act as a tumor suppressor, for example, it inhibits melanoma growth. Furthermore, TFCP2 is involved in epithelial-mesenchymal transition and enhances angiogenesis. TFCP2L1 maintains pluripotency and self-renewal of embryonic stem cells and was implicated in a wide variety of cancers, including clear cell renal cell carcinoma, breast cancer and thyroid cancer. Here we present a systematic review of current knowledge of this protein subfamily in the context of cancer. We also discuss potential challenges in investigating this family of transcription factors. These challenges include redundancies between these factors as well as their interactions with each other and their ability to modulate each other's activity.

The Therapeutic Potential of Targeting the HGF/cMET Axis in Ovarian Cancer

Survival rates for ovarian cancer have remained relatively stable for the past 2 decades despite advances in surgical techniques and cytotoxic chemotherapeutics, indicating a requirement for better therapies. One pathway currently proposed for targeting is the HGF/cMET pathway. Upregulated in a number of tumour types, cMET is a tyrosine kinase receptor expressed on epithelial cells. In ovarian cancer, it has been identified as highly expressed in the four major subtypes, with expression estimates ranging from 11 to 68 % of cases. HGF, the only known ligand for cMET, is found at high levels in both serum and ascites in women with ovarian cancer, and is proposed to induce both migration and metastasis. However, clinically validated biomarkers are not yet available for either HGF or cMET, preventing a clear understanding of the true rate of overexpression, or its correlation with prognosis. Despite this, a number of agents against HGF and cMET are currently being investigated in clinical trials for multiple tumour types, including ovarian. However, a lack of patient selection, biomarker usage, and post hoc analysis correlating response with expression has resulted in the majority of these trials showing little beneficial effect from these agents, indicating that additional research is required to determine their usefulness in patients with ovarian cancer.

Metformin disrupts malignant behavior of oral squamous cell carcinoma via a novel signaling involving Late SV40 factor/Aurora-A

Conventional therapeutic processes in patient with OSCC are associated with several unfavorable effects leading to patients with poor survival rate. Metformin has been shown to protect against a variety of specific diseases, including cancer. However, the precise roles and mechanisms underlying the therapeutic effects of metformin on OSCC remain elusive. In the current study, in vitro and xenograft model experiments revealed that metformin inhibited growth and metastasis of oral cancer cells. Importantly, metformin-restrained tumorigenesis of oral cancer was accompanied with strong decrease of both Aurora-A and Late SV40 Factor (LSF) expressions. Furthermore, LSF contributed to Aurora-A-elicited malignancy behaviors of oral cancer via binding to the promoter region of Aurora-A. A significant correlation was observed between LSF and Aurora-A levels in a cohort of specimens of oral cancer. These findings showed that a novel LSF/Aurora-A-signaling inhibition supports the rationale of using metformin as potential OSCC therapeutics.

Suppression of osteopontin inhibits chemically induced hepatic carcinogenesis by induction of apoptosis in mice

Previous clinical reports have found elevated osteopontin (OPN) levels in tumor tissues to be indicative of greater malignancy in human hepatocellular carcinoma (HCC). However, the role of OPN on carcinogenesis and its underlying mechanism remain unclear. In the present study, we investigated the oncogenic role of OPN in diethylnitrosamine (DEN)-induced hepatic carcinogenesis in mice. The overall incidence of hepatic tumors at 36 weeks was significantly lower in OPN knockout (KO) mice than in wild-type (WT) mice. Apoptosis was significantly enhanced in OPN KO mice, and was accompanied by the downregulation of epidermal growth factor receptor (EGFR). In the in vitro study, OPN suppression also led to lower mRNA and protein levels of EGFR associated with the downregulation of c-Jun in Hep3B and Huh7 human HCC cells lines, which resulted in increased apoptotic cell death in both cell lines. Moreover, a positive correlation was clearly identified between the expression of OPN and EGFR in human HCC tissues. These data demonstrate that the OPN deficiency reduced the incidence of chemically induced HCC by suppressing EGFR-mediated anti-apoptotic signaling. An important implication of our findings is that OPN positively contributes to hepatic carcinogenesis.

Role of Osteopontin in Liver Diseases

Osteopontin (OPN), a multifunctional protein, is involved in numerous pathological conditions including inflammation, immunity, angiogenesis, fibrogenesis and carcinogenesis in various tissues. Extensive studies have elucidated the critical role of OPN in cell signaling such as regulation of cell proliferation, migration, inflammation, fibrosis and tumor progression. In the liver, OPN interacts with integrins, CD44, vimentin and MyD88 signaling, thereby induces infiltration, migration, invasion and metastasis of cells. OPN is highlighted as a chemoattractant for macrophages and neutrophils during injury in inflammatory liver diseases. OPN activates hepatic stellate cells (HSCs) to exert an enhancer in fibrogenesis. The role of OPN in hepatocellular carcinoma (HCC) has also generated significant interests, especially with regards to its role as a diagnostic and prognostic factor. Interestingly, OPN acts an opposing role in liver repair under different pathological conditions. This review summarizes the current understanding of OPN in liver diseases. Further understanding of the pathophysiological role of OPN in cellular interactions and molecular mechanisms associated with hepatic inflammation, fibrosis and cancer may contribute to the development of novel strategies for clinical diagnosis, monitoring and therapy of liver diseases.

Small molecule inhibitors of Late SV40 Factor (LSF) abrogate hepatocellular carcinoma (HCC): Evaluation using an endogenous HCC model

Hepatocellular carcinoma (HCC) is a lethal malignancy with high mortality and poor prognosis. Oncogenic transcription factor Late SV40 Factor (LSF) plays an important role in promoting HCC. A small molecule inhibitor of LSF, Factor Quinolinone Inhibitor 1 (FQI1), significantly inhibited human HCC xenografts in nude mice without harming normal cells. Here we evaluated the efficacy of FQI1 and another inhibitor, FQI2, in inhibiting endogenous hepatocarcinogenesis. HCC was induced in a transgenic mouse with hepatocyte-specific overexpression of c-myc (Alb/c-myc) by injecting N-nitrosodiethylamine (DEN) followed by FQI1 or FQI2 treatment after tumor development. LSF inhibitors markedly decreased tumor burden in Alb/c-myc mice with a corresponding decrease in proliferation and angiogenesis. Interestingly, in vitro treatment of human HCC cells with LSF inhibitors resulted in mitotic arrest with an accompanying increase in CyclinB1. Inhibition of CyclinB1 induction by Cycloheximide or CDK1 activity by Roscovitine significantly prevented FQI-induced mitotic arrest. A significant induction of apoptosis was also observed upon treatment with FQI. These effects of LSF inhibition, mitotic arrest and induction of apoptosis by FQI1s provide multiple avenues by which these inhibitors eliminate HCC cells. LSF inhibitors might be highly potent and effective therapeutics for HCC either alone or in combination with currently existing therapies.

CD44 is a multidomain signaling platform that integrates extracellular matrix cues with growth factor and cytokine signals

The reception and integration of the plethora of signals a cell receives from its microenvironment is decisive in determining cell behavior. Perturbation of extracellular cues, or an inappropriate response to or integration of these signals lies at the root of many diseases such as cancer. The transmembrane protein CD44 contributes to the reception of a broad variety of microenvironmental components, including extracellular matrix constituents such as hyaluronic acid, as well as growth factors and cytokines. In this chapter, we review the range of extracellular cues that are recognized by CD44, and show how CD44 serves to integrate this information at several levels through the mechanisms by which it contributes to transduction of these various microenvironmental signals.

Characterization of genome-wide TFCP2 targets in hepatocellular carcinoma: implication of targets FN1 and TJP1 in metastasis

Background

Transcription factor CP2 (TFCP2) is overexpressed in hepatocellular carcinoma(HCC) and correlated with the progression of the disease. Here we report the use of an integrated systems biology approach to identify genome-wide scale map of TFCP2 targets as well as the molecular function and pathways regulated by TFCP2 in HCC.

Methods

We combined Chromatin immunoprecipitation (ChIP) on chip along with gene expression microarrays to study global transcriptional regulation of TFCP2 in HCC. The biological functions, molecular pathways, and networks associated with TFCP2 were identified using computational approaches. Validation of selected target gene expression and direct binding of TFCP2 to promoters were performed by ChIP -PCR and promoter reporter.

Results

TFCP2 fostered a highly aggressive and metastatic phenotype in different HCC cells. Transcriptome analysis showed that alteration of TFCP2 in HCC cells led to change of genes in biological functions involved in cancer, cellular growth and proliferation, angiogenesis, cell movement and attachment. Pathways related to cell movement and cancer progression were also enriched. A quest for TFCP2-regulated factors contributing to metastasis, by integration of transcriptome and ChIP on chip assay, identified fibronectin 1 (FN1) and tight junction protein 1 (TJP1) as targets of TFCP2, and as key mediators of HCC metastasis. Promoter reporter identified the TFCP2-responsive region, and located the motifs of TFCP2-binding sites in the FN1 promoter, which then was confirmed by ChIP-PCR. We further showed that FN1 inhibition blocks the TFCP2-induced increase in HCC cell aggression, and that overexpression of TFCP2 can rescue the effects of FN1 inhibition. Knock down of TJP1 could also rescue, at least in part, the aggressive effect of TFCP2 knockdown in HCC cells.

Conclusions

The identification of global targets, molecular pathways and networks associated with TFCP2, together with the discovery of the effect of TFCP2 on FN1 and TJP1 that are involved in metastasis, adds to our understanding of the mechanisms that determine a highly aggressive and metastatic phenotype in hepatocarcinogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0121-1) contains supplementary material, which is available to authorized users.

The molecular mechanism of HOTAIR in tumorigenesis, metastasis, and drug resistance

Long non-coding RNAs have been reported to play an important role in cellular metabolism and development. Homeobox transcript antisense intergenic RNA (HOTAIR), a long non-coding RNA, is pervasively over-expressed in most human cancers compared with non-cancerous adjacent tissues. Although many articles have reported that HOTAIR is closely associated with metastasis, epithelial-mesenchymal transition, advanced pathological stage, drug resistance, and poor prognosis, the role of HOTAIR in gene regulation and tumor development is largely unknown, and the potential molecular mechanisms are not completely clear yet. In this review, we summarized the recent progress in the study of the major functions of HOTAIR. miR-331-3p, miR-130a, miR-7, miR-141, HER2, c-MYC, WIF-1, RBM38, PTEN, and Col-1 are involved in the HOTAIR regulation network. We tried to elucidate the molecular mechanisms of HOTAIR in the aspects of tumorigenesis, metastasis, drug resistance, and regulation.

LSF expression and its prognostic implication in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of cancer death. Therapy failure was the first cause of death. LSF is a transcription factor regulating gene expression of angiogenesis, tumor invasion and proliferation, and is identified as a chemoresistant gene. Real-time PCR and Western blot to analyze mRNA and protein expression of LSF in 23 paired CRC samples. Immunohistochemistry was used to detect protein expression of LSF in 166 paired CRC samples. Both LSF mRNA and protein were upregulated in CRC. High LSF expression in CRC correlated with large tumor size, advanced pN stage, advanced AJCC stage and high Ki-67 index (P < 0.001). High expression of LSF favored worse prognosis. 5-year survival rates of LSF high and low expression were 39.6% and 78.6%, respectively. The 5-year median OS were 34 months and 57 months, respectively. LSF is an important mediator in CRC tumorigenesis and progression, and LSF expression is an important index for and prognostic prediction.

Osteopontin enhances the expression of HOTAIR in cancer cells via IRF1

Osteopontin (OPN), a secreted phosphoglycoprotein, plays important roles in tumor growth, invasion, and metastasis for many types of cancers. The long, noncoding RNA HOTAIR has been strongly associated with the invasion and metastasis of cancer cells. In this study, we found that recombinant human OPN could induce HOTAIR expression in a time- and dose-dependent manner, and our data also showed that OPN transcriptionally activated the expression of HOTAIR in cancer cells. Furthermore, through chromatin immunoprecipitation and luciferase activity assays, we found that IRF1 could bind to the HOTAIR promoter region and decrease its transcriptional activity, and cellular overexpression of IRF1 downregulated the level of HOTAIR. The receptor CD44 has also been verified as a regulator of OPN-induced HOTAIR expression. Interestingly, our data demonstrated that OPN could regulate PI3K/AKT and IRF1 expression and signaling, thereby influencing the expression of HOTAIR. In hepatocellular carcinoma samples, levels of HOTAIR correlated with the expression of OPN and IRF1. We therefore conclude that OPN, as an extracellular matrix protein, can stimulate the expression of HOTAIR by attenuating the inhibitory effect of IRF1, and this results in promotion of the invasion and metastasis of cancer cells.

Drug resistance mediated by AEG-1/MTDH/LYRIC

AEG-1/MTDH/LYRIC has been shown to promote cancer progression and development. Overexpression of AEG-1/MTDH/LYRIC correlates with angiogenesis, metastasis, and chemoresistance to various chemotherapy agents in cancer cells originating from a variety of tissues. In this chapter, we focus on the role of AEG-1/MTDH/LYRIC in drug resistance. Mechanistic studies have shown that AEG-1/MTDH/LYRIC is involved in classical oncogenic pathways including Ha-Ras, myc, NFκB, and PI3K/Akt. AEG-1/MTDH/LYRIC also promotes protective autophagy by activating AMP kinase and autophagy-related gene 5. Another reported mechanism by which AEG-1/MTDH/LYRIC regulates drug resistance is by increasing loading of multidrug resistance gene (MDR) 1 mRNA to the polysome, thereby facilitating MDR1 protein translation. More recently, a novel function for AEG-1/MTDH/LYRIC as an RNA-binding protein was elucidated, which has the potential to impact expression of drug sensitivity or resistance genes. Finally, AEG-1/MTDH/LYRIC acts in microRNA-directed gene silencing via an interaction with staphylococcal nuclease and tudor domain containing 1, a component of the RNA-induced silencing complex. Altered microRNA expression and activity induced by AEG-1/MTDH/LYRIC represent an additional way that AEG-1/MTDH/LYRIC may cause drug resistance in cancer. The multiple functions of AEG-1/MTDH/LYRIC in drug resistance highlight that it is a viable target as an anticancer agent for a wide variety of cancers.

AEG-1/MTDH/LYRIC in liver cancer

Hepatocellular carcinoma (HCC) is a highly virulent malignancy with diverse etiology. Identification of a common mediator of aggressive progression of HCC would be extremely beneficial not only for diagnostic/prognostic purposes but also for developing targeted therapies. AEG-1/MTDH/LYRIC gene is amplified in human HCC patients, and overexpression of AEG-1/MTDH/LYRIC has been identified in a high percentage of both hepatitis B virus and hepatitis C virus positive HCC cases, suggesting its key role in regulating hepatocarcinogenesis. Important insights into the molecular mechanisms mediating oncogenic properties of AEG-1/MTDH/LYRIC, especially regulating chemoresistance, angiogenesis, and metastasis, have been obtained from studies using HCC model. Additionally, analysis of HCC model has facilitated the identification of AEG-1/MTDH/LYRIC downstream genes and interacting proteins, thereby unraveling novel players regulating HCC development and progression leading to the development of novel interventional strategies. Characterization of a hepatocyte-specific AEG-1/MTDH/LYRIC transgenic mouse (Alb/AEG-1) has revealed novel aspects of AEG-1/MTDH/LYRIC function in in vivo contexts. Combination of AEG-1/MTDH/LYRIC inhibition and chemotherapy has documented significant efficacy in abrogating human HCC xenografts in nude mice indicating the need for developing effective AEG-1/MTDH/LYRIC inhibition strategies to obtain objective response and survival benefits in terminal HCC patients.

A DNA immunoprecipitation assay used in quantitative detection of in vitro DNA-protein complex binding

To begin gene transcription, several transcription factors must bind to specific DNA sequences to form a complex via DNA-protein interactions. We established an in vitro method for specific and sensitive analyses of DNA-protein interactions based on a DNA immunoprecipitation (DIP) method. We verified the accuracy and efficiency of the DIP assay in quantitatively measuring DNA-protein binding using transcription factor CP2c as a model. With our DIP assay, we could detect specific interactions within a DNA-CP2c complex, with reproducible and quantitative binding values. In addition, we were able to effectively measure the changes in DNA-CP2c binding by the addition of a small molecule, FQI1 (factor quinolinone inhibitor 1), previously identified as a specific inhibitor of this binding. To identify a new regulator of DNA-CP2c binding, we analyzed several CP2c binding peptides and found that only one class of peptide severely inhibits DNA-CP2c binding. These data show that our DIP assay is very useful in quantitatively detecting the binding dynamics of DNA-protein complex. Because DNA-protein interaction is very dynamic in different cellular environments, our assay can be applied to the detection of active transcription factors, including promoter occupancy in normal and disease conditions. Moreover, it may be used to develop a targeted regulator of specific DNA-protein interaction.

WNT1-inducible signaling pathway protein 1 contributes to ventilator-induced lung injury

Although strides have been made to reduce ventilator-induced lung injury (VILI), critically ill patients can vary in sensitivity to VILI, suggesting gene-environment interactions could contribute to individual susceptibility. This study sought to uncover candidate genes associated with VILI using a genome-wide approach followed by functional analysis of the leading candidate in mice. Alveolar-capillary permeability after high tidal volume (HTV) ventilation was measured in 23 mouse strains, and haplotype association mapping was performed. A locus was identified on chromosome 15 that contained ArfGAP with SH3 domain, ankyrin repeat and PH domain 1 (Asap1), adenylate cyclase 8 (Adcy8), WNT1-inducible signaling pathway protein 1 (Wisp1), and N-myc downstream regulated 1 (Ndrg1). Information from published studies guided initial assessment to Wisp1. After HTV, lung WISP1 protein increased in sensitive A/J mice, but was unchanged in resistant CBA/J mice. Anti-WISP1 antibody decreased HTV-induced alveolar-capillary permeability in sensitive A/J mice, and recombinant WISP1 protein increased HTV-induced alveolar-capillary permeability in resistant CBA/J mice. HTV-induced WISP1 coimmunoprecipitated with glycosylated Toll-like receptor (TLR) 4 in A/J lung homogenates. After HTV, WISP1 increased in strain-matched control lungs, but was unchanged in TLR4 gene-targeted lungs. In peritoneal macrophages from strain-matched mice, WISP1 augmented LPS-induced TNF release that was inhibited in macrophages from TLR4 or CD14 antigen gene-targeted mice, and was attenuated in macrophages from myeloid differentiation primary response gene 88 gene-targeted or TLR adaptor molecule 1 mutant mice. These findings support a role for WISP1 as an endogenous signal that acts through TLR4 signaling to increase alveolar-capillary permeability in VILI.

The transcription factor LSF: a novel oncogene for hepatocellular carcinoma

The transcription factor LSF (Late SV40 Factor), also known as TFCP2, belongs to the LSF/CP2 family related to Grainyhead family of proteins and is involved in many biological events, including regulation of cellular and viral promoters, cell cycle, DNA synthesis, cell survival and Alzheimer's disease. Our recent studies establish an oncogenic role of LSF in Hepatocellular carcinoma (HCC). LSF overexpression is detected in human HCC cell lines and in more than 90% cases of human HCC patients, compared to normal hepatocytes and liver, and its expression level showed significant correlation with the stages and grades of the disease. Forced overexpression of LSF in less aggressive HCC cells resulted in highly aggressive, angiogenic and multi-organ metastatic tumors in nude mice. Conversely, inhibition of LSF significantly abrogated growth and metastasis of highly aggressive HCC cells in nude mice. Microarray studies revealed that as a transcription factor LSF modulated specific genes regulating invasion, angiogenesis, chemoresistance and senescence. LSF transcriptionally regulates thymidylate synthase (TS) gene, thus contributing to cell cycle regulation and chemoresistance. Our studies identify a network of proteins, including osteopontin (OPN), Matrix metalloproteinase-9 (MMP-9), c-Met and complement factor H (CFH), that are directly regulated by LSF and play important role in LSF-induced hepatocarcinogenesis. A high throughput screening identified small molecule inhibitors of LSF DNA binding and the prototype of these molecules, Factor Quinolinone inhibitor 1 (FQI1), profoundly inhibited cell viability and induced apoptosis in human HCC cells without exerting harmful effects to normal immortal human hepatocytes and primary mouse hepatocytes. In nude mice xenograft studies, FQI1 markedly inhibited growth of human HCC xenografts as well as angiogenesis without exerting any toxicity. These studies establish a key role of LSF in hepatocarcinogenesis and usher in a novel therapeutic avenue for HCC, an invariably fatal disease.

Late SV40 factor (LSF) enhances angiogenesis by transcriptionally up-regulating matrix metalloproteinase-9 (MMP-9)

The transcription factor late SV40 factor (LSF) is overexpressed in human hepatocellular carcinoma (HCC) fostering a highly aggressive and metastatic phenotype. Angiogenesis is an essential component of cancer aggression and metastasis and HCC is a highly aggressive and angiogenic cancer. In the present studies, we analyzed the molecular mechanism of LSF-induced angiogenesis in HCC. Employing human umbilical vein endothelial cells (HUVEC) differentiation assay and chicken chorioallantoic membrane (CAM) assay we document that stable LSF overexpression augments and stable dominant negative inhibition of LSF (LSFdn) abrogates angiogenesis by human HCC cells. A quest for LSF-regulated factors contributing to angiogenesis, by chromatin immunoprecipitation-on-chip (ChIP-on-chip) assay, identified matrix metalloproteinase-9 (MMP-9) as a direct target of LSF. MMP-9 expression and enzymatic activity were higher in LSF-overexpressing cells and lower in LSFdn-expressing cells. Deletion mutation analysis identified the LSF-responsive regions in the MMP-9 promoter and ChIP assay confirmed LSF binding to the MMP-9 promoter. Inhibition of MMP-9 significantly abrogated LSF-induced angiogenesis as well as in vivo tumorigenesis, thus reinforcing the role of MMP-9 in facilitating LSF function. The present findings identify a novel target of LSF contributing to its oncogenic properties.