The expressions of bHLH gene HES1 and HES5 in advanced ovarian serous adenocarcinomas and their prognostic significance: a retrospective clinical study

Elevated Levels of Lamin A Promote HR and NHEJ-Mediated Repair Mechanisms in High-Grade Ovarian Serous Carcinoma Cell Line

Extensive research for the last two decades has significantly contributed to understanding the roles of lamins in the maintenance of nuclear architecture and genome organization which is drastically modified in neoplasia. It must be emphasized that alteration in lamin A/C expression and distribution is a consistent event during tumorigenesis of almost all tissues of human bodies. One of the important signatures of a cancer cell is its inability to repair DNA damage which befalls several genomic events that transform the cells to be sensitive to chemotherapeutic agents. This genomic and chromosomal instability is the most common feature found in cases of high-grade ovarian serous carcinoma. Here, we report elevated levels of lamins in OVCAR3 cells (high-grade ovarian serous carcinoma cell line) in comparison to IOSE (immortalised ovarian surface epithelial cells) and, consequently, altered damage repair machinery in OVCAR3. We have analysed the changes in global gene expression as a sequel to DNA damage induced by etoposide in ovarian carcinoma where lamin A is particularly elevated in expression and reported some differentially expressed genes associated with pathways conferring cellular proliferation and chemoresistance. We hereby establish the role of elevated lamin A in neoplastic transformation in the context of high-grade ovarian serous cancer through a combination of HR and NHEJ mechanisms.

Hairy and enhancer of split 1 (HES1) protects cells from endoplasmic reticulum stress-induced apoptosis through repression of

Disruption in endoplasmic reticulum (ER) function, termed ER stress, occurs in many diseases, including neurodegenerative disorders, diabetes, and cancer. Cells respond to ER stress with the unfolded protein response (UPR), which triggers a broad transcriptional program to restore and enhance ER function. Here, we found that ER stress up-regulates the mRNA encoding the developmentally regulated transcriptional repressor hairy and enhancer of split 1 (HES1), in a variety cell types. Depletion of HES1 increased cell death in response to ER stress in mouse and human cells, in a manner that depended on the pro-apoptotic gene growth arrest and DNA damage-inducible protein GADD34 (also known as Protein phosphatase 1 regulatory subunit 15A, or MyD116). Furthermore, HES1 bound to the GADD34 promoter, and its depletion led to an up-regulation of GADD34 expression during ER stress. Our results identify HES1 as a repressor of GADD34 expression, and reveal that HES1 contributes to cell fate determination in response to ER stress.

Upregulation of HES1 Promotes Cell Proliferation and Invasion in Breast Cancer as a Prognosis Marker and Therapy Target via the AKT Pathway and EMT Process

HES1 is a transcriptional repressor involved in cell differentiation and proliferation as well as in various cancer developments, but its expression pattern and biological roles in breast cancer have not been examined. In this study, we assessed HES1 expression in breast cancer tissues using immunohistochemistry and Western blot analyses and investigated HES1 function using MTT and Matrigel invasion assays. Significant relationships were observed between HES1 upregulation and advanced TNM stage (p=0.011), node metastasis (p=0.043), negative oestrogen receptor expression (p=0.001) and triple-negative status (p=0.001). HES1 overexpression was correlated with poor prognosis in breast cancer patients (p<0.05). The MTT and Matrigel invasion assays showed that silencing HES1 in MDA-MB-231 cells decreased cell proliferation and invasion, whereas overexpression of HES1 in MCF-7 cells enhanced its proliferation and invasion. Further analyses showed that silencing HES1 downregulated p-AKT and impeded epithelial-mesenchymal transition (EMT), whereas overexpression of HES1 upregulated AKT phosphorylation and induced EMT. Our study demonstrated that HES1 upregulation is a predictor of poor prognosis in human breast cancers and might be a critical contributor to the proliferation and invasion of breast cancer cells. Moreover, the proportion of cells with overexpression of HES1 in triple-negative breast cancer (TNBC) samples was significantly higher. Thus, HES1 might be a potential therapeutic target in the treatment of TNBC.

miR-940 Upregulation Suppresses Cell Proliferation and Induces Apoptosis by Targeting PKC-δ in Ovarian Cancer OVCAR3 Cells

Ovarian cancer remains as one of the most threatening malignancies for females in the world. This study investigated the pivotal role of miR-940 in the progression of ovarian cancer and to reveal the possible molecular mechanism of its action. Ovarian cancer OVCAR3 cells were transfected with the miR-940 vector, miR-940 inhibitor, and/or small interfering RNA (siRNA) targeting PKC-δ (si-PKC-δ), respectively. After transfection, cell viability and cell apoptosis were analyzed, as well as cell proliferation and apoptosis-related protein expression. Compared to the control, miR-940 upregulation suppressed cell viability but induced cell apoptosis. miR-940 upregulation increased the expression of p27, Hes1, survivin, and caspase 3, but decreased the expression of PKC-δ. In addition, elevated cell viability induced by the miR-940 inhibitor was significantly decreased by knockdown of PKC-δ, and reduced cell apoptosis induced by the miR-940 inhibitor was increased by knockdown of PKC-δ. Taken together, the results of our study suggest that upregulation of miR-940 may function as a suppressor in the progression of ovarian cancer by inhibiting cell proliferation and inducing apoptosis by targeting PKC-δ. This study may provide a basis for the possible application of miR-940 in illustrating the molecular pathogenic mechanism of ovarian cancer.

Rap1A promotes ovarian cancer metastasis via activation of ERK/p38 and notch signaling

As one of the Ras-associated proteins, Rap1A has been linked to cancer initiation and development. However, the precise function of Rap1A in ovarian cancer is still not understood. Here, we show that Rap1A promotes ovarian cancer tumorigenesis and metastasis via stimulating cell proliferation, migration and invasion both in vivo and in vitro. Mechanistic study showed that Rap1A activates extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and Notch pathways, leading to the enhanced expression of several epithelial-mesenchymal transition (EMT) markers such as slug, zeb1, vimentin, fibronectin, and MMP9. However, the pretreatment of Rap1A-overexpressing cells with the Notch inhibitor DAPT or ERK inhibitor (U0126) inhibited the up-regulated expression of those molecules. These findings provide the first evidence linking Rap1A with ovarian cancer development through the ERK/p38 and Notch signaling pathways, indicating that Rap1A may be used as a novel diagnostic marker or a therapeutic target for ovarian cancer.

Hes1 Increases the Invasion Ability of Colorectal Cancer Cells via the STAT3-MMP14 Pathway

The Notch pathway contributes to self-renewal of tumor-initiating cell and inhibition of normal colonic epithelial cell differentiation. Deregulated expression of Notch1 and Jagged1 is observed in colorectal cancer. Hairy/enhancer of split (HES) family, the most characterized targets of Notch, involved in the development of many cancers. In this study, we explored the role of Hes1 in the tumorigenesis of colorectal cancer. Knocking down Hes1 induced CRC cell senescence and decreased the invasion ability, whereas over-expression of Hes1 increased STAT3 phosphorylation activity and up-regulated MMP14 protein level. We further explored the expression of Hes1 in human colorectal cancer and found high Hes1 mRNA expression is associated with poor prognosis in CRC patients. These findings suggest that Hes1 regulates the invasion ability through the STAT3-MMP14 pathway in CRC cells and high Hes1 expression is a predictor of poor prognosis of CRC.

Characterization of Notch Signalling Pathway Members in Normal Prostate, Prostatic Intraepithelial Neoplasia (PIN) and Prostatic Adenocarcinoma

Prostate Cancer (PCa) holds the second place in terms of cancer-related mortality rate among men. The Notch signalling pathway regulates the proliferation and differentiation in embryonic and adult tissues and determines the cell fate. The body of knowledge in the present literature is currently controversial about the effect of the Notch pathway on prostatic cancer. Therefore, the present study aimed to examine the immunolocalization and expression levels of Notch1-4, Jagged1-2, Delta, HES1 and HES5 from among the members of the Notch signalling pathway in tissues of normal, prostatic intraepithelial neoplasia (PIN) and malignant prostate. The current study included a sample of 20 patients with localised prostatic adenocarcinoma, 18 patients with high grade PIN (H-PIN) and 18 normal prostatic tissue. Immunolocalisations of Notch1, 2, 3, 4, Jagged1, 2, Delta, HES1 and HES5 were identified through the immunohistochemical method. The findings of the present study showed that all in-scope members of the Notch signalling pathway were localised in PIN structures to a greater extent than in other tissues and from amongst these members, specifically Notch1, Notch4, Jagged1 and HES1 were at more significant levels. Consequently, the findings of the present study may indicate that the Notch signalling pathway can play a role especially in the formation of PIN structures.

A 10-gene expression signature of Notch pathway predicts recurrence in ovarian carcinoma

Patients with ovarian carcinoma are at high risk of tumor recurrence. In the present study, 81 Notch pathway genes were selected to find recurrence-related genes in The Cancer Genome Atlas dataset. A 10-gene signature (FZD4, HES1, PSEN2, JAG2, PPARG, FOS, HEY1, CDC16, MFNG, and EP300) was identified and validated that is associated with recurrence-free survival time, but not with overall survival time, in the TCGA dataset and in other two independent datasets, GSE9891 and GSE30161. This gene signature gave a significant performance in discriminating patients at high risk of recurrence from those at low risk, as measured by the area under the receiver operating characteristic curve. Cox proportional hazards regression analyses demonstrated that the prognostic value of this 10-gene set is independent of other clinical variables in all three datasets. The potential as a biomarker for predicting high- and low-risk subgroups for recurrence in ovarian cancer patients deserves further investigation in prospective patient cohorts in the future.

HES1 promotes metastasis and predicts poor survival in patients with colorectal cancer

Hairy enhancer of split-1 (HES1) is a transcriptional target of the Notch pathway, and a high level of HES1 is regarded as a marker of activated Notch. The aim of the study was to investigate the role of HES1 in colorectal cancer progression. We used tissue microarrays to analyze the expression and clinical significance of HES1 in 320 colorectal cancer samples. Stable overexpression and knockdown of HES1 were established in three colorectal cancer cell (CRC) lines (RKO, HCT8 and LOVO). We investigated the differentially expressed genes and enriched pathways in HES1 overexpressing CRC cells by gene expression profiling. Also, the role of HES1 in invasion and migration were examined in vitro and in vivo. We found that high expression of HES1 was significantly correlated with distal metastasis (P = 0.037) at diagnosis, and HES1 could serve as an unfavorable prognostic factor for colorectal cancer patients (P = 0.034). Gene expression profiling and pathway enrichment analysis revealed that HES1 was related to cellular adherens junction loss. In addition, we showed that HES1 overexpression lead to depressed E-cadherin, and elevated N-cadherin, vimentin and Twist-1 levels. Functionally, HES1 enhanced invasiveness and metastasis of CRC cells. HES1 promotes cancer metastasis via inducing epithelial mesenchymal transition and serves as a poor prognosis factor of colorectal cancer patients.

Aberrant regulation of FBW7 in cancer

FBW7 (F-box and WD repeat domain-containing 7) or Fbxw7 is a tumor suppressor, which promotes the ubiquitination and subsequent degradation of numerous oncoproteins including Mcl-1, Cyclin E, Notch, c- Jun, and c-Myc. In turn, FBW7 is regulated by multiple upstream factors including p53, C/EBP-δ, EBP2, Pin1, Hes-5 and Numb4 as well as by microRNAs such as miR-223, miR-27a, miR-25, and miR-129-5p. Given that the Fbw7 tumor suppressor is frequently inactivated or deleted in various human cancers, targeting FBW7 regulators is a promising anti-cancer therapeutic strategy.

Pathway modulations and epigenetic alterations in ovarian tumorbiogenesis

Cellular pathways are numerous and are highly integrated in function in the control of cellular systems. They collectively regulate cell division, proliferation, survival and apoptosis of cells and mutagenesis of key genes that control these pathways can initiate neoplastic transformations. Understanding these pathways is crucial to future therapeutic and preventive strategies of the disease. Ovarian cancers are of three major types; epithelial, germ-cell, and stromal. However, ovarian cancers of epithelial origin, arising from the mesothelium, are the predominant form. Of the subtypes of ovarian cancer, the high-grade serous tumors are fatal, with low survival rate due to late detection and poor response to treatments. Close examination of preserved ovarian tissues and in vitro studies have provided insights into the mechanistic changes occurring in cells mediated by a few key genes. This review will focus on pathways and key genes of the pathways that are mutated or have aberrant functions in the pathology of ovarian cancer. Non-genetic mechanisms that are gaining prominence in the pathology of ovarian cancer, miRNAs and epigenetics, will also be discussed in the review.

Notch-induced transcription factors are predictive of survival and 5-fluorouracil response in colorectal cancer patients

Background:

The purpose of this study was to evaluate the expression of Notch-induced transcription factors (NTFs) HEY1, HES1 and SOX9 in colorectal cancer (CRC) patients to determine their clinicopathologic and prognostic significance.

Methods:

Levels of HEY1, HES1 and SOX9 protein were measured by immunohistochemistry in a nonmalignant and malignant tissue microarray of 441 CRC patients, and the findings correlated with pathologic, molecular and clinical variables.

Results:

The NTFs HEY1, HES1 and SOX9 were overexpressed in tumours relative to colonic mucosa (OR=3.44, P<0.0001; OR=7.40, P<0.0001; OR=4.08 P<0.0001, respectively). HEY1 overexpression was a negative prognostic factor for all CRC patients (HR=1.29, P=0.023) and strongly correlated with perineural and vascular invasion and lymph node (LN) metastasis. In 5-fluorouracil (5-FU)-treated patients, the tumour overexpression of SOX9 correlated with markedly poorer survival (HR=8.72, P=0.034), but had no predictive effect in untreated patients (HR=0.70, P=0.29). When HEY1, HES1 and SOX9 expression were combined to predict survival with chemotherapy, in treated patients there was an additive increase in the risk of death with each NTF overexpressed (HR=2.09, P=0.01), but no prognostic import in the untreated patient group (HR=0.74, P=0.19).

Conclusion:

The present study is the first to discover that HEY1 overexpression correlates with poorer outcome in CRC, and NTF expression is predictive of CRC patient survival with 5-FU chemotherapy. If confirmed in future studies, testing of NTF expression has the potential to enter routine pathological practice for the selection of patients to undergo chemotherapy alone or in combination with Notch inhibitors.

HES1, a target of Notch signaling, is elevated in canine osteosarcoma, but reduced in the most aggressive tumors

BACKGROUND

Hairy and enhancer of split 1 (HES1), a basic helix-loop-helix transcriptional repressor, is a downstream target of Notch signaling. Notch signaling and HES1 expression have been linked to growth and survival in a variety of human cancer types and have been associated with increased metastasis and invasiveness in human osteosarcoma cell lines. Osteosarcoma (OSA) is an aggressive cancer demonstrating both high metastatic rate and chemotherapeutic resistance. The current study examined expression of Notch signaling mediators in primary canine OSA tumors and canine and human osteosarcoma cell lines to assess their role in OSA development and progression.

RESULTS

Reverse transcriptase - quantitative PCR (RT-qPCR) was utilized to quantify HES1, HEY1, NOTCH1 and NOTCH2 gene expression in matched tumor and normal metaphyseal bone samples taken from dogs treated for appendicular OSA at the Colorado State University Veterinary Teaching Hospital. Gene expression was also assessed in tumors from dogs with a disease free interval (DFI) of <100 days compared to those with a DFI > 300 days following treatment with surgical amputation followed by standard chemotherapy. Immunohistochemistry was performed to confirm expression of HES1. Data from RT-qPCR and immunohistochemical (IHC) experiments were analyzed using REST2009 software and survival analysis based on IHC expression employed the Kaplan-Meier method and log rank analysis. Unbiased clustered images were generated from gene array analysis data for Notch/HES1 associated genes. Gene array analysis of Notch/HES1 associated genes suggested alterations in the Notch signaling pathway may contribute to the development of canine OSA. HES1 mRNA expression was elevated in tumor samples relative to normal bone, but decreased in tumor samples from dogs with a DFI < 100 days relative to those with a DFI > 300 days. NOTCH2 and HEY1 mRNA expression was also elevated in tumors relative to normal bone, but was not differentially expressed between the DFI tumor groups. Survival analysis confirmed an association between decreased HES1 immunosignal and shorter DFI.

CONCLUSIONS

Our findings suggest that activation of Notch signaling occurs and may contribute to the development of canine OSA. However, association of low HES1 expression and shorter DFI suggests that mechanisms that do not alter HES1 expression may drive the most aggressive tumors.

Identification of small molecule Hes1 modulators as potential anticancer chemotherapeutics

Hes1 is a key transcriptional regulator primarily controlled by the Notch signaling pathway, and recent studies have demonstrated both an oncogenic and tumor suppressor role for Hes1, depending on the cell type. Small molecules that activate and inhibit Hes1 activity hold promise as future anticancer chemotherapeutics. We have utilized a cell-based dual luciferase assay to identify modulators of Hes1 expression in a medium-throughput format. A modest screen was performed in HCT-116 colon cancer cell lines, and two small molecules were identified and characterized as Hes1 regulators. Compound 3 induced Hes1 expression and exhibited anticancer effects in pulmonary carcinoid tumor cells, a cell type in which the upregulated Notch/Hes1 signaling plays a tumor suppressive role. Treatment of HCT-116 cells with compound 12 resulted in Hes1 downregulation and antitumor effects.