Overexpression of hedgehog pathway molecules and FOXM1 in non-small cell lung carcinomas

Long non-coding RNA (CMR) involved in autoprotection in S. aureus mastitis in dairy cows by regulating miR-877/FOXM1

Long non-coding RNAs (LncRNAs) are dysregulated in a variety of human diseases and are highly involved in the development and progression of tumors. Studies on lncRNAs associated with cow mastitis have been lagging behind compared to humans or model animals, therefore, the aim of this study was to explore the mechanism of LncRNAs (CMR) involved in autoprotection against S. aureus mastitis in Bovine Mammary Epithelial Cells (BMECs). First, qRT-PCR was used to examine the relative expression of CMR in a S. aureus mastitis model of BMECs. Then, cell proliferation and apoptosis were detected by EdU and apoptosis assay. Finally, the targeting relationship between miRNAs and mRNA/LncRNAs was determined by dual luciferase reporter gene, qRT-PCR and western blotting techniques. The results showed that CMR was upregulated in the S. aureus mastitis model of BMECs and promoted the expression of inflammatory factors, and SiRNA-mediated CMR inhibited the proliferation of mammary epithelial cells and induced apoptosis. Mechanistically, CMR acts as a competitive endogenous RNA (ceRNA) sponge miR-877, leading to upregulation of FOXM1, a target of miR-877. Importantly, either miR-877 overexpression or FOXM1 inhibition abrogated CMR knockdown-induced apoptosis promoting cell proliferation and reducing inflammatory factor expression levels. In summary, CMR is involved in the regulation of autoprotection against S. aureus mastitis through the miR-877/FOXM1 axis in BMECs and induces immune responses in mammary tissues and cells of dairy cows, providing an important reference for subsequent prevention and control of cow mastitis and the development of targeted drugs.

Modulation of the ubiquitin-proteasome system by phytochemicals: Therapeutic implications in malignancies with an emphasis on brain tumors

Regarding the multimechanistic nature of cancers, current chemo- or radiotherapies often fail to eradicate disease pathology, and frequent relapses or resistance to therapies occur. Brain malignancies, particularly glioblastomas, are difficult-to-treat cancers due to their highly malignant and multidimensional biology. Unfortunately, patients suffering from malignant tumors often experience poor prognoses and short survival periods. Thus far, significant efforts have been conducted to discover novel and more effective modalities. To that end, modulation of the ubiquitin-proteasome system (UPS) has attracted tremendous interest since it affects the homeostasis of proteins critically engaged in various cell functions, for example, cell metabolism, survival, proliferation, and differentiation. With their safe and multimodal actions, phytochemicals are among the promising therapeutic tools capable of turning the operation of various UPS elements. The present review, along with an updated outline of the role of UPS dysregulation in multiple cancers, provided a detailed discussion on the impact of phytochemicals on the UPS function in malignancies, especially brain tumors.

A Sonic Hedgehog Pathway Score to Predict the Outcome of Resected Non-Small Cell Lung Cancer Patients

BACKGROUND

Mutations and deregulations in components of the Hedgehog (Hh) pathway have been associated with cancer onset and tumor growth in different malignancies, but their role in non-small cell lung cancer (NSCLC) remains unclear. This study aims to investigate the expression pattern of the main components of the Hh pathway in tumor and adjacent normal tissue biopsies of resected NSCLC patients.

METHODS

The relative expression of GLI1, PTCH1, SHH, and SMO was analyzed by quantitative polymerase chain reaction (PCR) in a cohort of 245 NSCLC patients. Results were validated in an independent cohort of NSCLC patients from The Cancer Genome Atlas (TCGA).

RESULTS

We found that SMO and GLI1 were overexpressed in the tumor compared with normal-paired tissue, whereas PTCH1 and SHH were underexpressed. In addition, patients with higher expression levels of PTCH1 presented better outcomes. A gene expression score, called the Hedgehog Score, was calculated using a multivariable model including analyzed components of the Hh signaling pathway. NSCLC patients with a high Hedgehog Score had significantly shorter relapse-free survival (RFS) and overall survival (OS) than patients with a low score, especially at stage I of the disease. Similarly, patients in the adenocarcinoma (ADC) subcohort had shorter RFS and OS. Multivariate Cox analysis exhibited that the Hedgehog Score is an independent prognostic biomarker for OS in both the entire training cohort and the ADC subcohort. The Hedgehog Score was validated in an independent cohort of NSCLC patients from TCGA, which confirmed its prognostic value.

CONCLUSIONS

Our results provide relevant prognostic data for NSCLC patients and support further studies on the Hh pathway.

The role of fascin-1 in the pathogenesis, diagnosis and management of respiratory related cancers

Human cancer statistics report that respiratory related cancers such as lung, laryngeal, oral and nasopharyngeal cancers account for a large proportion of tumors, and tumor metastasis remains the major reason for patient death. The metastasis of tumor cells requires actin cytoskeleton remodeling, in which fascin-1 plays an important role. Fascin-1 can cross-link F-actin microfilaments into bundles and form finger-like cell protrusions. Some studies have shown that fascin-1 is overexpressed in human tumors and is associated with tumor growth, migration and invasion. The role of fascin-1 in respiratory related cancers is not very clear. The main purpose of this study was to provide an updated literature review on the role of fascin-1 in the pathogenesis, diagnosis and management of respiratory related cancers. These studies suggested that fascin-1 can serve as an emerging biomarker and potential therapeutic target, and has attracted widespread attention.

High Circulating Sonic Hedgehog Protein Is Associated With Poor Outcome in EGFR-Mutated Advanced NSCLC Treated With Tyrosine Kinase Inhibitors

Introduction

Growing preclinical evidence has suggested that the Sonic hedgehog (Shh) pathway is involved in resistance to tyrosine kinase inhibitor (TKI) therapy for EGFR-mutated (EGFRm) non-small cell lung cancer (NSCLC). However, little is known concerning the prognostic value of this pathway in this context.

Materials and Methods

We investigated the relationship between plasma levels of Shh and EGFRm NSCLC patients’ outcome with EGFR TKIs. We included 74 consecutive patients from two institutions with EGFRm advanced NSCLC treated by EGFR TKI as first-line therapy. Plasma samples were collected longitudinally for each patient and were analyzed for the expression of Shh using an ELISA assay. The activation of the Shh–Gli1 pathway was assessed through immunohistochemistry (IHC) of Gli1 and RT-qPCR analysis of the transcripts of Gli1 target genes in 14 available tumor biopsies collected at diagnosis (baseline).

Results

Among the 74 patients, only 61 had baseline (diagnosis) plasma samples, while only 49 patients had plasma samples at the first evaluation. Shh protein was detectable in all samples at diagnosis (n = 61, mean = 1,041.2 ± 252.5 pg/ml). Among the 14 available tumor biopsies, nuclear expression of Gli1 was observed in 57.1% (8/14) of patients’ biopsies. Shh was significantly (p < 0.05) enriched in youth (age < 68), male, nonsmokers, patients with a PS > 1, and patients presenting more than 2 metastatic sites and L858R mutation. Higher levels of Shh correlated with poor objective response to TKI, shorter progression-free survival (PFS), and T790M-independent mechanism of resistance. In addition, the rise of plasma Shh levels along the treatment was associated with the emergence of drug resistance in patients presenting an initial good therapy response.

Conclusion

These data support that higher levels of plasma Shh at diagnosis and increased levels of Shh along the course of the disease are related to the emergence of TKI resistance and poor outcome for EGFR-TKI therapy, suggesting that Shh levels could stand both as a prognostic and as a resistance biomarker for the management of EGFR-mutated NSCLC patients treated with EGFR-TKI.

Downregulation of hedgehog-interacting protein (HHIP) contributes to hexavalent chromium-induced malignant transformation of human bronchial epithelial cells

Hexavalent chromium [Cr(VI)] is a potent human lung carcinogen. Multiple mechanisms have been proposed that contribute to Cr(VI)-induced lung carcinogenesis including oxidative stress, DNA damage, genomic instability and epigenetic modulation. However, the molecular mechanisms and pathways mediating Cr(VI) carcinogenicity have not been fully elucidated. Hedgehog (Hh) signaling is a key pathway that plays important roles in the formation of multiple tissues during embryogenesis and in the maintenance of stem cell populations in adults. Dysregulation of Hh signaling pathway has been reported in many human cancers. Here, we report a drastic reduction in both mRNA and protein levels of hedgehog-interacting protein (HHIP), a downstream target and a negative regulator of Hh signaling, in Cr(VI)-transformed cells. These findings point to a potential role of Hh signaling in Cr(VI)-induced malignant transformation and lung carcinogenesis. Cr(VI)-transformed cells exhibited DNA hypermethylation and silencing histone marks in the promoter region of HHIP, indicating that an epigenetic mechanism mediates Cr(VI)-induced silencing of HHIP. In addition, the major targets of Hh signaling (GLI1-3 and PTCH1) were significantly increased in Cr(VI)-transformed cells, suggesting an aberrant activation of Hh signaling in these cells. Moreover, ectopically expressing HHIP not only suppressed Hh signaling but also inhibited cell proliferation and anchorage-independent growth in Cr(VI)-transformed cells. In conclusion, these findings establish a novel regulatory mechanism underlying Cr(VI)-induced lung carcinogenesis and provide new insights for developing a better diagnostic and prognostic strategy for Cr(VI)-related human lung cancer.

GPC3 affects the prognosis of lung adenocarcinoma and lung squamous cell carcinoma

Background

Glypican 3 (GPC3) is a heparin sulphate proteoglycan whose expression is associated with several malignancies. However, its expression in non-small-cell lung carcinoma (NSCLC) is limited and ambiguous. This study aimed to comprehensively evaluate the expression of GPC3 in NSCLC and develop a risk-score model for predicting the prognosis of NSCLC.

Methods

The gene expression profiles of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) were downloaded from the UCSC Xena database. Using the limma package, the differentially expressed genes (DEGs) between different comparison groups were analysed and the differential expression of GPC3 was calculated. A functional enrichment analysis was conducted for GPC3-associated genes using the DAVID tool. For the GPC3-associated genes shared by the four comparison groups, a protein–protein interaction network was built using the Cytoscape software. After conducting a survival analysis and a Cox regression analysis, the genes found to be significantly correlated with prognosis were selected to construct a risk-score model. Besides, the gene and protein levels of GPC3 were examined by quantitative reverse transcriptase-PCR (qRT-PCR) and immunohistochemistry (IHC) in LUSC tissues and paracancer tissues.

Results

The differential expression of GPC3 was significant (adjusted P < 0.05) in the NSCLC vs. normal, LUAD vs. normal, LUSC versus normal, and LUAD versus. LUSC comparison groups. GPC3 directly interacted with SERPINA1, MFI2, and FOXM1. Moreover, GPC3 expression was significantly correlated with pathologic N, pathologic T, gender, and tumour stage in LUAD samples. Finally, the risk-score model (involving MFI2, FOXM1, and GPC3) for LUAD and that (involving SERPINA1 and FOXM1) for LUSC were established separately. The qRT-PCR result showed that GPC3 expression was much higher in the LUSC tissues than that in the normal group. The IHC results further showed that GPC3 is highly expressed in LUSC tissues, but low in paracancer tissues.

Conclusion

The three-gene risk-score model for LUAD and the two-gene risk-score model for LUSC might be valuable in improving the prognosis of these carcinomas.

FOXM1 and Cancer: Faulty Cellular Signaling Derails Homeostasis

Forkhead box transcription factor, FOXM1 is implicated in several cellular processes such as proliferation, cell cycle progression, cell differentiation, DNA damage repair, tissue homeostasis, angiogenesis, apoptosis, and redox signaling. In addition to being a boon for the normal functioning of a cell, FOXM1 turns out to be a bane by manifesting in several disease scenarios including cancer. It has been given an oncogenic status based on several evidences indicating its role in tumor development and progression. FOXM1 is highly expressed in several cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in angiogenesis, invasion, migration, self- renewal and drug resistance. In this review, we attempt to understand various mechanisms underlying FOXM1 gene and protein regulation in cancer including the different signaling pathways, post-transcriptional and post-translational modifications. Identifying crucial molecules associated with these processes can aid in the development of potential pharmacological approaches to curb FOXM1 mediated tumorigenesis.

HEDGEHOG/GLI Modulates the PRR11-SKA2 Bidirectional Transcription Unit in Lung Squamous Cell Carcinomas

We previously demonstrated that proline-rich protein 11 (PRR11) and spindle and kinetochore associated 2 (SKA2) constituted a head-to-head gene pair driven by a prototypical bidirectional promoter. This gene pair synergistically promoted the development of non-small cell lung cancer. However, the signaling pathways leading to the ectopic expression of this gene pair remains obscure. In the present study, we first analyzed the lung squamous cell carcinoma (LSCC) relevant RNA sequencing data from The Cancer Genome Atlas (TCGA) database using the correlation analysis of gene expression and gene set enrichment analysis (GSEA), which revealed that the PRR11-SKA2 correlated gene list highly resembled the Hedgehog (Hh) pathway activation-related gene set. Subsequently, GLI1/2 inhibitor GANT-61 or GLI1/2-siRNA inhibited the Hh pathway of LSCC cells, concomitantly decreasing the expression levels of PRR11 and SKA2. Furthermore, the mRNA expression profile of LSCC cells treated with GANT-61 was detected using RNA sequencing, displaying 397 differentially expressed genes (203 upregulated genes and 194 downregulated genes). Out of them, one gene set, including BIRC5, NCAPG, CCNB2, and BUB1, was involved in cell division and interacted with both PRR11 and SKA2. These genes were verified as the downregulated genes via RT-PCR and their high expression significantly correlated with the shorter overall survival of LSCC patients. Taken together, our results indicate that GLI1/2 mediates the expression of the PRR11-SKA2-centric gene set that serves as an unfavorable prognostic indicator for LSCC patients, potentializing new combinatorial diagnostic and therapeutic strategies in LSCC.

Cancer Stem Cell Niche in Colorectal Cancer and Targeted Therapies

Cancer stem cells (CSCs), also known as tumor-initiating cells, are a sub-population of tumor cells found in many human cancers that are endowed with self-renewal and pluripotency. CSCs may be more resistant to conventional anticancer therapies than average cancer cells, as they can easily escape the cytotoxic effects of standard chemotherapy, thereby resulting in tumor relapse. Despite significant progress in related research, effective elimination of CSCs remains an unmet clinical need. CSCs are localized in a specialized microenvironment termed the niche, which plays a pivotal role in cancer multidrug resistance. The niche components of CSCs, such as the extracellular matrix, also physically shelter CSCs from therapeutic agents. Colorectal cancer is the most common malignancy worldwide and presents a relatively transparent process of cancer initiation and development, making it an ideal model for CSC niche research. Here, we review recent advances in the field of CSCs using colorectal cancer as an example to illustrate the potential therapeutic value of targeting the CSC niche. These findings not only provide a novel theoretical basis for in-depth discussions on tumor occurrence, development, and prognosis evaluation, but also offer new strategies for the targeted treatment of cancer.

Galectin-1 promotes vasculogenic mimicry in gastric adenocarcinoma via the Hedgehog/GLI signaling pathway

Background: Galectin-1 (GAL-1), which is encoded by LGALS1, promotes vasculogenic mimicry (VM) in gastric cancer (GC) tissue. However, the underlying mechanism remains unclear.

Methods: Immunohistochemical (IHC) and CD34-periodic acid-Schiff (PAS) double staining were used to investigate Glioma-associated oncogene-1(GLI1) expression and VM in paraffin-embedded sections from 127 patients with GC of all tumor stages. LGALS1 or GLI1 were stably transduced into MGC-803 cells and AGS cells, and western blotting, IHC, CD34-PAS double staining and three-dimensional culture in vitro, and tumorigenicity in vivo were used to explore the mechanisms of GAL-1/ GLI1 promotion of VM formation in GC tissues.

Results: A significant association between GAL-1 and GLI1 expression was identified by IHC staining, as well as a significant association between GLI1 expression and VM formation. Furthermore, overexpression of LGALS1 enhanced expression of GLI1 in MGC-803 and AGS cells. GLI1 promoted VM formation both in vitro and in vivo. The effects of GLI1 on VM formation were independent of LGALS1. Importantly, the expression of VM-related molecules, such as MMP2, MMP14 and laminin5γ2, was also affected upon GLI1 overexpression or silencing in GC cell lines. Conclusion: GAL-1 promotes VM in GC through the Hh/GLI pathway, which has potential as a novel therapeutic target for treatment of VM in GC.

Cyclin F and KIF20A, FOXM1 target genes, increase proliferation and invasion of ovarian cancer cells

Increased expression of FOXM1 is observed in a variety of human malignancies. The downstream target genes of FOXM1 involved in tumorigenesis and development are not fully elucidated in ovarian cancer. Here, we identified Cyclin F, a substrate recognition subunit of SCF (Skp1-Cul1-F-box protein) complex, and Kinesin Family Member 20A (KIF20A) were transcriptionally regulated by FOXM1 in ovarian cancer. Accordingly, Cyclin F and KIF20A were commonly overexpressed in ovarian cancer. Functionally, forced expression of Cyclin F or KIF20A significantly enhanced while knockdown of them decreased proliferation and invasion of ovarian cancer cells. Importantly, high levels of Cyclin F and KIF20A correlated with poor prognosis in patients with ovarian cancer. Our findings indicate that Cyclin F and KIF20A are functional targets of FOXM1 which might be potential drug targets in ovarian cancer.

GLI1 activation is a key mechanism of erlotinib resistance in human non-small cell lung cancer

Lung cancer is the leading cause of cancer-associated death worldwide. In recent years, the advancement of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) targeted therapies has provided clinical benefits for lung cancer patients with EGFR mutations. The response to EGFR-TKI varies in patients with lung cancer, and resistance typically develops during the course of the treatment. Therefore, understanding biomarkers which can predict resistance to EGFR-TKI is important. Overexpression of GLI causes activation of the Hedgehog (Hh) signaling pathway and plays a critical role in oncogenesis in numerous types of cancer. In the present study, the role of GLI1 in erlotinib resistance was investigated. GLI1 mRNA and protein expression levels were determined using reverse transcription-quantitative PCR and immunohistochemistry (IHC) in lung cancer cell lines and tumor specimens, respectively. GLI1 mRNA expression levels were found to be positively correlated with the IC₅₀ of erlotinib in 15 non-small cell lung cancer (NSCLC) cell lines. The downregulation of GLI1 using siRNA sensitized lung cancer cells to the erlotinib treatment, whereas the overexpression of GLI1 increased the survival of lung cancer cells in the presence of erlotinib, indicating that Hh/GLI activation may play a critical role in the development of TKI resistance in lung cancer. Combined treatment with erlotinib and a GLI1 inhibitor reduced the cell viability synergistically. A retrospective study of patients with NSCLC treated with erlotinib revealed that those with a high IHC score for GLI1 protein expression had a poorer prognosis. These results indicated that GLI1 is a key regulator for TKI sensitivity, and patients with lung cancer may benefit from the combined treatment of TKI and GLI1 inhibitor.

PKAc-directed interaction and phosphorylation of Ptc is required for Hh signaling inhibition in Drosophila

Ptc is a gatekeeper to avoid abnormal Hh signaling activation, but the key regulators involved in Ptc-mediated inhibition remain largely unknown. Here, we identify PKAc as a key regulator required for Ptc inhibitory function. In the absence of Hh, PKAc physically interacts with Ptc and phosphorylates Ptc at Ser-1150 and -1183 residues. The presence of Hh unleashes PKAc from Ptc and activates Hh signaling. By combining both in vitro and in vivo functional assays, we demonstrate that such Ptc–PKAc interaction and Ptc phosphorylation are both important for Ptc inhibitory function. Interestingly, we further demonstrate that PKAc is subjected to palmitoylation, contributing to its kinase activity on plasma membrane. Based on those novel findings, we establish a working model on Ptc inhibitory function: In the absence of Hh, PKAc interacts with and phosphorylates Ptc to ensure its inhibitory function; and Hh presence releases PKAc from Ptc, resulting in Hh signaling activation.

Inhibition of the hedgehog pathway for the treatment of cancer using Itraconazole

Itraconazole (ITZ) is an anti-fungal drug that has been used in clinical practice for nearly 35 years. Recently, numerous experiments have shown that ITZ possesses anti-cancer properties. The Hedgehog (Hh) pathway plays a pivotal role in fundamental processes, including embryogenesis, structure, morphology and proliferation in various species. This pathway is typically silent in adult cells, and inappropriate activity is linked to various tumor types. The most important mechanism of ITZ in the treatment of cancer is inhibition of the Hh pathway through the inhibition of smoothened receptors (SMO), glioma-associated oncogene homologs (GLI), and their downstream targets. In this review, we discuss the mechanisms of ITZ in the treatment of cancer through inhibition of the Hh pathway, which includes anti-inflammation, prevention of tumor growth, induction of cell cycle arrest, induction of apoptosis and autophagy, prevention of angiogenesis, and drug resistance. We also discuss the clinical use of ITZ in many types of cancers. We hope this review will provide more information to support future studies on ITZ in the treatment of various cancers.

GATA-6 transcriptionally inhibits Shh to repress cell proliferation and migration in lung squamous cell carcinoma

GATA-6 is a transcription factor that participates in cell lineage differentiation and organogenesis in many tissue types. The abnormal expression of GATA-6 is associated with the development of diverse cancers. GATA-6 acts as an oncogene or tumor suppressor based on tumor origin. Here, we investigated the effects of GATA-6 on lung squamous cell carcinoma (LSCC). We found that GATA-6 was significantly reduced in LSCC tissues compared with the paired normal tissues. The overexpression of GATA-6 inhibited LSCC cell proliferation and migration. Importantly, a luciferase reporter assay and chromatin immunoprecipitation assay demonstrated that GATA-6 negatively regulated the expression of sonic hedgehog (Shh) by directly binding to its promoter region. Furthermore, N-Shh stimulation rescued the inhibition of LSCC cell proliferation and migration upon GATA-6 overexpression. Thus, GATA-6 inhibited the proliferation and migration of LSCC cells by transcriptionally inhibiting the expression of Shh, indicating that targeting GATA-6 may be a potential approach for LSCC therapy.

The multifaceted roles of FOXM1 in pulmonary disease

Forkhead box M1 (FOXM1), a transcriptional regulator of G1/S and G2/M transition and M phase progression in the cell cycle, plays a principal role in many physiological and pathological processes. A growing number of studies have focused on the relationship between abnormal FOXM1 expression and pulmonary diseases, such as lung cancer, chronic obstructive pulmonary disease (COPD), asthma, acute lung injury (ALI), pulmonary fibrosis, and pulmonary arterial hypertension (PAH). These studies indicate that the FOXM1 regulatory network is a major predictor of poor outcomes, especially in lung cancer, and provide novel insight into various pulmonary diseases. For the first time, this review summarizes the mechanistic relationship between FOXM1 dysregulation and pulmonary diseases, the benefits of targeting abnormal FOXM1 expression, and the questions that remain to be addressed in the future.

Targeted next-generation sequencing reveals recurrence-associated genomic alterations in early-stage non-small cell lung cancer

Purpose

The identification of genomic alterations related to recurrence in early-stage non-small cell lung cancer (NSCLC) patients may help better stratify high-risk individuals and guide treatment strategies. This study aimed to identify the molecular biomarkers of recurrence in early-stage NSCLC.

Results

Of the 42 tumors evaluable for genomic alterations, TP53 and EGFR were the most frequent alterations with population frequency 52.4% and 50.0%, respectively. Fusion genes were detected in four patients, which had lower mutational burden and relatively better genomic stability. EGFR mutation and fusion gene were mutually exclusive in this study. CDKN2A, FAS, SUFU and SMARCA4 genomic alterations were only observed in the relapsed patients. Increased copy number alteration index was observed in early relapsed patients. Among these genomic alterations, early-stage NSCLCs harboring CDKN2A, FAS, SUFU and SMARCA4 genomic alterations were found to be significantly associated with recurrence. Some of these new findings were validated using The Cancer Genome Atlas (TCGA) dataset.

Conclusions

The genomic alterations of CDKN2A, FAS, SUFU and SMARCA4 in early-stage NSCLC are found to be associated with recurrence, but confirmation in a larger independent cohort is required to define the clinical impact.

Materials and Methods

Paired primary tumor and normal lung tissue samples were collected for targeted next-generation sequencing analysis. A panel targets exons for 440 genes was used to assess the mutational and copy number status of selected genes in three clinically relevant groups of stage I/II NSCLC patients: 1) Early relapse; 2) Late relapse; and 3) No relapse.

Prognostic significance of FOXM1 in oral squamous cell carcinoma patients treated by docetaxel-containing regimens

Forkhead box protein M1 (FOXM1) is an oncoprotein that is involved in cell proliferation, differentiation and aging, and overexpression of FOXM1 is thought to be associated with the development and progression of various types of cancer. The expression of FOXM1 was retrospectively examined in tumor tissues taken from 56 oral squamous cell carcinoma (OSCC) patients by immunohistochemical staining. All of these patients received docetaxel (Doc)-containing regimens as treatments against OSCC. The association between FOXM1 expression and the clinicopathological characteristics and prognosis of these patients was then examined. FOXM1 was expressed in the nucleus and cytoplasm of OSCC tissues samples. There was a significant association between FOXM1 expression in tumor tissues and N classification (P=0.0395), stage (P=0.004), therapeutic efficacy (P=0.0113) and outcome (P=0.0134) of patients. However, FOXM1 expression had no association with patients' sex, age or T classification. Additionally, high expression of FOXM1 in tumor cells was associated with a shorter overall survival (P=0.0257) of patients. Multivariate analysis also revealed that elevated expression of FOXM1 was a predictor of patients' poor survival (P=0.0327). The results suggested that high expression of FOXM1 in OSCC tumors may result in reduced therapeutic effects and poor clinical outcomes of patients receiving Doc-based treatment regimens.

Expression of Numb and Gli1 in malignant pleural mesothelioma and their clinical significance

AIM OF STUDY

Malignant pleural mesothelioma (MPM) is a highly lethal and refractory to multimodal treatment tumor. Numb is considered as a tumor suppressor playing critical roles in determining cell fate and has been shown to target the oncogenic transcription factor Gli1 for Itch-dependent ubiquitination, resulting in suppression of the oncogenic sonic hedgehog signaling in medulloblastoma. This study was designed to analysis the role of Numb and Gli1 in MPM.

MATERIALS AND METHODS

Tissues of 61 MPM patients and 22 normal pleura as control were investigated. Numb and Gli1 expression were evaluated by immunohistochemistry. The associations with clinical and pathological parameters of the two markers were statistically analyzed, and the correlation between them was also demonstrated.

RESULTS

The expression levels of Numb with nuclear Gli1 exhibited a significant inverse correlation (r = -0.361 P < 0.05). In addition, Numb has an inverse correlation with ki-67 labeling index (P < 0.05), and nuclear Gli1 was found in associated with the tumor International Mesothelioma Interest Group-stage (P < 0.05). The overall survival was influenced by the expression of Numb (P < 0.05) and histological subtype (P < 0.05), further regression analysis showed that only histological subtype has a prognostic influence on survival (P < 0.05).

CONCLUSION

The results provide new evidence of Numb and Gli1 on the clinical characteristics of MPM, which may be helpful in clinical diagnosis and targeted therapy. Further research with larger sample size is needed.

Gli1 promotes colorectal cancer metastasis in a Foxm1-dependent manner by activating EMT and PI3K-AKT signaling

Colorectal cancer(CRC) is one of the most commonly diagnosed cancers in human beings and metastasis is the main death reason. Recently, Gli1 has been reported to be a key regulator of various cancer biologies and genes expressions. However, the detailed molecular mechanism of Gli1 in CRC metastasis remains largely unknown. In this study, we aimed to investigate the role of Gli1 in CRC metastasis. We used qRT-PCR, Immunohistochemistry and Western blot to test the expression levels of Gli1, Foxm1 and other target genes in the tissues and cells; Lentivirus stable transfection to change the expression levels of Gli1 and Foxm1; Wound-healing, cell invasion, migration assays and tail vein metastatic assay to test the role of Gli1 in CRC metastasis in vitro and vivo. We demonstrated that Gli1 was significantly overexpressed in colorectal cancer tissues and cells. Foxm1 level had a positive correlation with Gli1. Furthermore, we found that Gli1 promotes colorectal cancer cells metastasis in a Foxm1-dependent manner by activating EMT and PI3K-AKT signaling. Thus, we proved that Gli1 plays important role in CRC metastasis and provided a new visual field on the therapy of CRC metastasis.

Targeting GLI by GANT61 involves mechanisms dependent on inhibition of both transcription and DNA licensing

The GLI genes are transcription factors and in cancers are oncogenes, aberrantly and constitutively activated. GANT61, a specific GLI inhibitor, has induced extensive cytotoxicity in human models of colon cancer. The FOXM1 promoter was determined to be a transcriptional target of GLI1. In HT29 cells, inhibition of GLI1 binding at the GLI consensus sequence by GANT61 led to inhibited binding of Pol II, the pause-release factors DSIF, NELF and p-TEFb. The formation of R-loops (RNA:DNA hybrids, ssDNA), were reduced by GANT61 at the FOXM1 promoter. Pretreatment of HT29 cells with α-amanitin reduced GANT61-induced γH2AX foci. Co-localization of GLI1 and BrdU foci, inhibited by GANT61, indicated GLI1 and DNA replication to be linked. By co-immunoprecipitation and confocal microscopy, GLI1 co-localized with the DNA licensing factors ORC4, CDT1, and MCM2. Significant co-localization of GLI1 and ORC4 was inhibited by GANT61, and enrichment of ORC4 occurred at the GLI binding site in the FOXM1 promoter. CDT1 was found to be a transcription target of GLI1. Overexpression of CDT1 in HT29 and SW480 cells reduced GANT61-induced cell death, gH2AX foci, and cleavage of caspase-3. Data demonstrate involvement of transcription and of DNA replication licensing factors by non-transcriptional and transcriptional mechanisms in the GLI-dependent mechanism of action of GANT61.

Old Sonic Hedgehog, new tricks: a new paradigm in thoracic malignancies

The Sonic Hedgehog (Shh) pathway is physiologically involved during embryogenesis, but is also activated in several diseases, including solid cancers. Previous studies have demonstrated that the Shh pathway is involved in oncogenesis, tumor progression and chemoresistance in lung cancer and mesothelioma. The Shh pathway is also closely associated with epithelial-mesenchymal transition and cancer stem cells. Recent findings have revealed that a small proportion of lung cancer cells expressed an abnormal full-length Shh protein, associated with cancer stem cell features. In this paper, we review the role of the Shh pathway in thoracic cancers (small cell lung cancer, non-small cell lung cancer, and mesothelioma) and discuss the new perspectives of cancer research highlighted by the recent data of the literature.

Disruption of SHH signaling cascade by SBE attenuates lung cancer progression and sensitizes DDP treatment

Deregulated Sonic Hedgehog (SHH) pathway facilitates the initiation, progression, and metastasis of Non-small cell lung cancer (NSCLC), confers drug resistance and renders a therapeutic interference option to lung cancer patients with poor prognosis. In this study, we screened and evaluated the specificity of a Chinese herb Scutellariabarbata D. Don extraction (SBE) in repressing SHH signaling pathway to block NSCLC progression. Our study confirmed that aberrant activation of the SHH signal pathway conferred more proliferative and invasive phenotypes to human lung cancer cells. This study revealed that SBE specifically repressed SHH signaling pathway to interfere the SHH-mediated NSCLC progression and metastasis via arresting cell cycle progression. We also found that SBE significantly sensitized lung cancer cells to chemotherapeutic agent DDP via repressing SHH components in vitro and in vivo. Mechanistic investigations indicated that SBE transcriptionally and specifically downregulated SMO and consequently attenuated the activities of GLI1 and its downstream targets in SHH signaling pathway, which interacted with cell cycle checkpoint enzymes to arrest cell cycle progression and lead to cellular growth inhibition and migration blockade. Collectively, our results suggest SBE as a novel drug candidate for NSCLC which specifically and sensitively targets SHH signaling pathway.

Itraconazole induces apoptosis and cell cycle arrest via inhibiting Hedgehog signaling in gastric cancer cells

BACKGROUND

Itraconazole has been proved therapeutically effective against a variety of human cancers. This study assessed the effect of itraconazole on the Hedgehog (Hh) pathway and proliferation of human gastric cancer cells.

METHODS

CCK-8 assay and colony formation assay were used to assess the effects of itraconazole on proliferation of gastric cancer cells. The expression of Hh signaling components in gastric cancer cells treated with itraconazole was evaluated by reverse-transcription polymerase chain reaction, immunoblotting and dual luciferase assay. Tumor xenograft models were used to assess the inhibitory effect of itraconazole on the proliferation of gastric cancer cells in vivo.

RESULTS

Itraconazole could remarkably inhibit the proliferation of gastric cancer cells. When in combination with 5-FU, itraconazole significantly reduced the proliferation rate of cancer cells. Furthermore, itraconazole could regulate the G₁-S transition and induce apoptosis of gastric cancer cells. Hh signaling was abnormally activated in human gastric cancer samples. In vitro, studies showed that the expression of glioma-associated zinc finger transcription factor 1 (Gli1) was decreased at both transcriptional and translational levels after treatment with itraconazole. Dual luciferase assay also indicated that itraconazole could inhibit the transcription of Gli1. In vivo studies demonstrated that monotherapy with itraconazole by oral administration could inhibit the growth of xenografts, and that itraconazole could significantly enhance the antitumor efficacy of the chemotherapeutic agent 5-FU.

CONCLUSIONS

Hh signaling is activated in gastric tumor and itraconazole can inhibit the growth of gastric cancer cells by inhibiting Gli1 expression.

The Hedgehog Signaling Networks in Lung Cancer: The Mechanisms and Roles in Tumor Progression and Implications for Cancer Therapy

Lung cancer is the most common cause of cancer-related death worldwide and is classified into small cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). Several gene mutations that contribute to aberrant cell proliferation have been identified in lung adenocarcinoma, a part of NSCLC. Various anticancer drugs that target these mutated molecules have been developed for NSCLC treatment. However, although molecularly targeted drugs are initially effective for patients, the 5-year survival rate remains low because of tumor relapse. Therefore, more effective drugs for lung cancer treatment should be developed. The hedgehog (HH) signaling pathway contributes to organ development and stem cell maintenance, and aberrant activation of this signaling pathway is observed in various cancers including lung cancer. In lung cancer, HH signaling pathway upregulates cancer cell proliferation and maintains cancer stem cells as well as cancer-associated fibroblasts (CAFs). Furthermore, physical contact between CAFs and NSCLC cells induces HH signaling pathway activation in NSCLC cells to enhance their metastatic potential. Therefore, HH signaling pathway inhibitors could be a useful option for lung cancer therapy.

microRNA-214 promotes epithelial-mesenchymal transition and metastasis in lung adenocarcinoma by targeting the suppressor-of-fused protein (Sufu)

Distant metastasis is the major cause of cancer-related deaths in patients with lung adenocarcinoma (LAD). Emerging evidence reveals that miRNA is critical for tumor metastasis. miR-214 expression has been associated with LAD progression. However, whether and how miR-214 is involved in the development and metastasis of LAD remain unaddressed. Here, we found that the expression of miR-214 was elevated in LAD and correlated positively with LAD metastasis and epithelial-mesenchymal transition (EMT). In addition, we found that miR-214 enhanced the molecular program controlling the EMT of LAD cells and promoted LAD cell metastasis both in vitro and in vivo. This study thus provides the first evidence to show that the miR-214 expression by LAD cells contributes to the EMT and metastasis of LAD. Mechanistically, Sufu was identified as an important miR-214 functional target for the EMT and metastasis of LAD, ectopic expression of Sufu alleviated miR-214 promoted EMT and metastasis. Importantly, the expression of Sufu inversely correlated with the expression of miR-214 and vimentin and positively associated with the expression of E-cadherin in the tumor cells from human LAD patients. Collectively, this study uncovers a previously unappreciated miR-214-Sufu pathway in controlling EMT and metastasis of LAD and suggests that interfering with miR-214 and Sufu could be a viable approach to treat late stage metastatic LAD patients.

[Clinical value of Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy in the treatment of advanced non-small cell lung cancer: a Meta-analysis]

OBJECTIVE

To investigate the clinical efficacy and safety of Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy in the treatment of advanced non-small cell lung cancer (NCSLC) compared with chemotherapy alone.

METHODS

Databases including Chinese National Knowledge Infrastructure, China Biology Medicine Disc, Wanfang, and MEDLINE were searched until April 1, 2014. Two assessors independently reviewed each trial. The primary outcome was the effective rate (ER) of Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy. The secondary outcomes included quality of life improvement rate (QOLIR) and adverse reactions. Statistical calculations were performed by using Cochrane Collaboration Review Manager 5.2.

RESULTS

A total of 888 patients from 15 studies, 13 randomized controlled trials (RCT) and two controlled clinical trials, were included. Compared with chemotherapy alone, Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract plus chemotherapy significantly improved ER [Risk ratio (RR) = 1.32, 95% CI, (1.14, 1.54)] (based on 15 studies) and QOLIR [RR = 2.04, 95% CI, (1.69, 2.47)] (based on 13 studies). Compared with chemotherapy alone, Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract plus chemotherapy significantly inhibited chemotherapy-induced white blood cell decline [RR = 0.79, 95% CI, (0.70, 0.90) (based on 10 studies), chemotherapy-induced platelet decline [RR = 0.77, 95% CI, (0.60, 0.98)] (based on 8 studies), and significantly alleviated nausea and vomiting (NV) [RR = 0.83, 95% CI, (0.71, 0.97)] (based on 7 studies). There was no significant difference in hemoglobin decline between the two therapies [RR = 0.88, 95% CI, (0.70, 1.09)] (based on 6 studies).

CONCLUSION

This Meta-analysis suggests that Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy may be more efficacious in the treatment of advanced NSCLC than chemotherapy alone. This effect includes enhancing ER and QOLIR, and weakening chemotherapy toxicity. However, large-scale RCTs are required to further investigate the short- and long-term effects of Tongguanteng (Radix seu Herba Marsdeniae Tenacissimae) extract.

Association between FOXM1 and hedgehog signaling pathway in human cervical carcinoma by tissue microarray analysis

Forkhead box M1 (FOXM1) and hedgehog (Hh) signaling pathway are implicated in the formation and development of human tumors, including cervical cancer. Previous studies have indicated that FOXM1 may be a downstream target gene of the Hh signaling pathway, but their association in cervical cancer is largely unknown. In the present study, the expression of FOXM1 and Hh signaling molecules was evaluated by immunohistochemical analysis in a tissue microarray that contained 70 cervical cancer tissues and 10 normal cervical tissues. In addition, the association of these molecules with clinicopathological parameters, and the association between FOXM1 and various molecules involved in the Hh signaling pathway was investigated. The results indicated that FOXM1 and Hh signaling molecules were overexpressed in cervical cancer tissues. The protein expression levels of FOXM1, glioma-associated oncogene 1 (GLI1) and smoothened (SMO) correlated with the clinical stage of the tumors, while the protein expression levels of Sonic Hh (SHh), patched 1 (PTCH1) and GLI1 correlated with the pathological grade of the tumors. The expression levels of GLI1 were lower in tissues without lymph node metastasis than in tissues with lymph node metastasis. In addition, FOXM1 expression correlated with GLI1, SHh and PTCH1 expression in cancer tissues. These findings confirmed the participation of FOXM1 and the Hh signaling pathway in cervical cancer. Furthermore, the finding that FOXM1 may be a downstream target gene of the Hh signaling pathway in cervical cancer provides a potential novel diagnostic and therapeutic target for cervical cancer.

Set7 mediated Gli3 methylation plays a positive role in the activation of Sonic Hedgehog pathway in mammals

Hedgehog signaling plays very important roles in development and cancers. Vertebrates have three transcriptional factors, Gli1, Gli2 and Gli3. Among them, Gli3 is a very special transcriptional factor which closely resembles Cubitus interruptus (Ci, in Drosophila) structurally and functionally as a ‘double agent’ for Shh target gene expression. Here we show that Gli3 full-length, but not the truncated form, can be methylated at K436 and K595. This methylation is specifically catalyzed by Set7, a lysine methyltransferase (KMT). Methylation at K436 and K595 respectively increases the stability and DNA binding ability of Gli3, resulting in an enhancement of Shh signaling activation. Furthermore, functional experiments indicate that the Gli3 methylation contributes to the tumor growth and metastasis in non-small cell lung cancer in vitro and in vivo. Therefore, we propose that Set7 mediated methylation is a novel PTM of Gli3, which positively regulates the transactivity of Gli3 and the activation of Shh signaling.

DOI:http://dx.doi.org/10.7554/eLife.15690.001

Cells in mammals need to be able to communicate with each other to enable them to work together in tissues and organs. A signaling pathway called Hedgehog signaling plays a crucial role in carrying information between cells in developing embryos, but if it is active at other times it can also promote the development of cancers.

The Hedgehog signaling pathway regulates the activity of several proteins, including one called Gli3. When the Hedgehog signaling pathway is not active, Gli3 is able to switch off certain genes in the cells. On the other hand, when the signaling pathway is active, Gli3 changes shape so that it is able to activate its target genes instead. It is thought that this shape change is triggered by the addition (or removal) of chemical tags to Gli3. So far, researchers have reported that several different types of chemical tags can modify the activity of Gli3. However, it is not clear whether another type of chemical tag – known as a methyl tag – is involved in regulating Gli3.

Fu et al. studied Hedgehog signaling in mice. The experiments show that an enzyme called Set7 can modify Gli3 by adding methyl tags to certain sites in the protein. This modification makes the protein’s structure more stable and helps it to bind to the target genes. Further experiments show that these methyl groups contribute to the progression of lung cancer. Fu et al.’s findings expand our understanding of how chemical tags can alter the cells’ response to Hedgehog signaling activity. Future challenges are to understand exactly how Set7 and Gli3 interact and to develop drugs that can block this interaction, which may have the potential to treat cancer.

DOI:http://dx.doi.org/10.7554/eLife.15690.002

Blockade of Hedgehog Signaling Synergistically Increases Sensitivity to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small-Cell Lung Cancer Cell Lines

Aberrant activation of the hedgehog (Hh) signaling pathway has been implicated in the epithelial-to-mesenchymal transition (EMT) and cancer stem-like cell (CSC) maintenance; both processes can result in tumor progression and treatment resistance in several types of human cancer. Hh cooperates with the epidermal growth factor receptor (EGFR) signaling pathway in embryogenesis. We found that the Hh signaling pathway was silenced in EGFR-TKI-sensitive non-small-cell lung cancer (NSCLC) cells, while it was inappropriately activated in EGFR-TKI-resistant NSCLC cells, accompanied by EMT induction and ABCG2 overexpression. Upregulation of Hh signaling through extrinsic SHH exposure downregulated E-cadherin expression and elevated Snail and ABCG2 expression, resulting in gefitinib tolerance (P < 0.001) in EGFR-TKI-sensitive cells. Blockade of the Hh signaling pathway using the SMO antagonist SANT-1 restored E-cadherin expression and downregulate Snail and ABCG2 in EGFR-TKI-resistant cells. A combination of SANT-1 and gefitinib markedly inhibited tumorigenesis and proliferation in EGFR-TKI-resistant cells (P < 0.001). These findings indicate that hyperactivity of Hh signaling resulted in EGFR-TKI resistance, by EMT introduction and ABCG2 upregulation, and blockade of Hh signaling synergistically increased sensitivity to EGFR-TKIs in primary and secondary resistant NSCLC cells. E-cadherin expression may be a potential biomarker of the suitability of the combined application of an Hh inhibitor and EGFR-TKIs in EGFR-TKI-resistant NSCLCs.

Combined Use of Gene Expression Modeling and siRNA Screening Identifies Genes and Pathways Which Enhance the Activity of Cisplatin When Added at No Effect Levels to Non-Small Cell Lung Cancer Cells In Vitro

Platinum-based combination chemotherapy is the standard treatment for advanced non-small cell lung cancer (NSCLC). While cisplatin is effective, its use is not curative and resistance often emerges. As a consequence of microenvironmental heterogeneity, many tumour cells are exposed to sub-lethal doses of cisplatin. Further, genomic heterogeneity and unique tumor cell sub-populations with reduced sensitivities to cisplatin play a role in its effectiveness within a site of tumor growth. Being exposed to sub-lethal doses will induce changes in gene expression that contribute to the tumour cell’s ability to survive and eventually contribute to the selective pressures leading to cisplatin resistance. Such changes in gene expression, therefore, may contribute to cytoprotective mechanisms. Here, we report on studies designed to uncover how tumour cells respond to sub-lethal doses of cisplatin. A microarray study revealed changes in gene expressions that occurred when A549 cells were exposed to a no-observed-effect level (NOEL) of cisplatin (e.g. the IC₁₀). These data were integrated with results from a genome-wide siRNA screen looking for novel therapeutic targets that when inhibited transformed a NOEL of cisplatin into one that induced significant increases in lethality. Pathway analyses were performed to identify pathways that could be targeted to enhance cisplatin activity. We found that over 100 genes were differentially expressed when A549 cells were exposed to a NOEL of cisplatin. Pathways associated with apoptosis and DNA repair were activated. The siRNA screen revealed the importance of the hedgehog, cell cycle regulation, and insulin action pathways in A549 cell survival and response to cisplatin treatment. Results from both datasets suggest that RRM2B, CABYR, ALDH3A1, and FHL2 could be further explored as cisplatin-enhancing gene targets. Finally, pathways involved in repairing double-strand DNA breaks and INO80 chromatin remodeling were enriched in both datasets, warranting further research into combinations of cisplatin and therapeutics targeting these pathways.

Sonic Hedgehog Pathway Activation Is Associated With Resistance to Platinum-Based Chemotherapy in Advanced Non-Small-Cell Lung Carcinoma

INTRODUCTION

Chemoresistance is a major challenge in the treatment of advanced non-small-cell lung cancer (NSCLC). Because the Sonic hedgehog (Shh) pathway is reactivated in NSCLC, we investigated an association between chemoresistance and Shh activation.

PATIENTS AND METHODS

From a cohort of 178 patients with advanced NSCLC treated with platinum-based chemotherapy as first-line treatment, we selected all surgical tumor samples at diagnosis (n = 36). Shh activation was evaluated through Gli1 and Gli2 expression using immunohistochemistry (quantitative score). In vitro treatment studies with cisplatin or vismodegib (Shh pathway inhibitor), or both, were performed on NSCLC cell lines (H322 and A549) and primary cultures from patients with sarcomatoid carcinoma (n = 4).

RESULTS

Of the 36 patients, 12 had NSCLC refractory to chemotherapy (R-patients, 33.3%) and 24 had controlled disease (C-patients). Gli1 expression did not differ between the R- and C-patients (P = .35). Gli2 expression was more often positive in the R-patients (41.7% vs. 8.3%; P = .02). Progression-free survival (PFS) and overall survival (OS) in patients with a Gli2-positive score was 2.1 and 8.0 months, respectively, compared with 6.7 and 18.0 months for patients with a Gli2-negative score (P = .03 and P = .002, respectively). On multivariate analysis, the Gli2 score correlated independently with PFS (hazard ratio [HR], 2.64; 95% confidence interval [CI], 1.05-6.63; P = .04) and OS (HR, 4.36; 95% CI, 1.67-11.36; P = .003). The sarcomatoid carcinoma cell lines were more resistant to cisplatin than were the H838 and A549 cell lines. The cisplatin-vismodegib combination displayed a synergistic cytotoxic effect in the most chemoresistant cells in vitro.

CONCLUSION

The Shh pathway is associated with resistance to platinum-based chemotherapy in NSCLC.

Siomycin A Induces Apoptosis in Human Lung Adenocarcinoma A549 Cells by Suppressing the Expression of FoxM1

Forkhead box M1 (FoxM1), a transcription factor of the Forkhead family, is demonstrated to be critical for proliferation, apoptosis, migration and invasion of lung cancer. In this study, we extensively investigated the anticancer effect of siomycin A, which was identified as an inhibitor of FoxM1 transcriptional activity, on human lung adenocarcinoma A549 cells. Our study indicated that treatment with siomycin A resulted in the suppression of FoxM1 expression, which consequently contributed to its effect of cell growth inhibition and cell apoptosis induction in A549 cells. Then the molecular mechanism of siomycin A's apoptotic action on A549 cells was further investigated. The results revealed that siomycin A induced apoptosis by influencing the downstream events of FoxM1, including inhibiting the expression of Bcl-2 and Mcl-1, as well as leading to caspase-3 cleavage. Taken together, our findings may be useful for understanding the mechanism of action of siomycin A on lung cancer cells and provide new insights into the possible application of such a compound in lung cancer therapy in the future.

The Hedgehog signalling pathway mediates drug response of MCF-7 mammosphere cells in breast cancer patients

BCSCs (breast cancer stem cells) have been shown to be resistant to chemotherapy. However, the mechanisms underlying BCSC-mediated chemoresistance remain poorly understood. The Hh (Hedgehog) pathway is important in the stemness maintenance of CSCs. Nonetheless, it is unknown whether the Hh pathway is involved in BCSC-mediated chemoresistance. In the present study, we cultured breast cancer MCF-7 cells in suspension in serum-free medium to obtain BCSC-enriched MCF-7 MS (MCF-7 mammosphere) cells. We showed that MCF-7 MS cells are sensitive to salinomycin, but not paclitaxel, distinct from parent MCF-7 cells. The expression of the critical components of Hh pathway, i.e., PTCH (Patched), SMO (Smoothened), Gli1 and Gli2, was significantly up-regulated in MCF-7 MS cells; salinomycin, but not paclitaxel, treatment caused a remarkable decrease in expression of those genes in MCF-7 MS cells, but not in MCF-7 cells. Salinomycin, but not paclitaxel, increased apoptosis, decreased the migration capacity of MCF-7 MS cells, accompanied by a decreased expression of c-Myc, Bcl-2 and Snail, the target genes of the Hh pathway. The salinomycin-induced cytotoxic effect could be blocked by Shh (Sonic Hedgehog)-mediated Hh signalling activation. Inhibition of the Hh pathway by cyclopamine could sensitize MCF-7 MS cells to paclitaxel. In addition, salinomycin, but not paclitaxel, significantly reduced the tumour growth, accompanied by decreased expression of PTCH, SMO, Gli1 and Gli2 in xenograft tumours. Furthermore, the expression of SMO and Gli1 was positively correlated with the expression of CD44+ / CD24-, and the expression of SMO and Gli1 in CD44+ / CD24- tissues was associated with a significantly shorter OS (overall survival) and DFS (disease-free survival) in breast cancer patients receiving chemotherapy.

SMO Gene Amplification and Activation of the Hedgehog Pathway as Novel Mechanisms of Resistance to Anti-Epidermal Growth Factor Receptor Drugs in Human Lung Cancer

PURPOSE

Resistance to tyrosine kinase inhibitors (TKI) of EGF receptor (EGFR) is often related to activation of other signaling pathways and evolution through a mesenchymal phenotype.

EXPERIMENTAL DESIGN

Because the Hedgehog (Hh) pathway has emerged as an important mediator of epithelial-to-mesenchymal transition (EMT), we studied the activation of Hh signaling in models of EGFR-TKIs intrinsic or acquired resistance from both EGFR-mutated and wild-type (WT) non-small cell lung cancer (NSCLC) cell lines.

RESULTS

Activation of the Hh pathway was found in both models of EGFR-mutated and EGFR-WT NSCLC cell line resistant to EGFR-TKIs. In EGFR-mutated HCC827-GR cells, we found SMO (the Hh receptor) gene amplification, MET activation, and the functional interaction of these two signaling pathways. In HCC827-GR cells, inhibition of SMO or downregulation of GLI1 (the most important Hh-induced transcription factor) expression in combination with MET inhibition exerted significant antitumor activity.In EGFR-WT NSCLC cell lines resistant to EGFR inhibitors, the combined inhibition of SMO and EGFR exerted a strong antiproliferative activity with a complete inhibition of PI3K/Akt and MAPK phosphorylation. In addition, the inhibition of SMO by the use of LDE225 sensitizes EGFR-WT NSCLC cells to standard chemotherapy.

CONCLUSIONS

This result supports the role of the Hh pathway in mediating resistance to anti-EGFR-TKIs through the induction of EMT and suggests new opportunities to design new treatment strategies in lung cancer.

Variant of BCL3 gene is strongly associated with five-year survival of non-small-cell lung cancer patients

OBJECTIVES

BCL3, a known atypical IκB family member, has been documented to be upregulated in hematological malignancies and in some solid tumors, functioning as a crucial player in tumor development. Recently, rs8100239, a tag-Single Nucleotide Polymorphism (SNP) in BCL3 (T>A) has been identified, but there are no data regarding its involvement in non-small-cell lung cancer (NSCLC) initiation and progression.

MATERIALS AND METHODS

To study the possible association of BCL3 with NSCLC, 268 patients and 279 healthy controls were genotyped for rs8100239. Moreover, BCL3 protein expression was also investigated in 112 NSCLC cases through an immunohistochemical analysis.

RESULTS

NSCLC patients with AA genotype displayed significantly worse prognosis compared to T allele carriers (P<0.001), who had less frequent intermediate nuclear BCL3 expression (P=0.042). In addition, overexpression of BCL3 was detected in tumor specimens, compared to normal tissue (P<0.001). Furthermore, BCL3 protein levels were associated with five-year survival (P=0.039), maximum diameter of lesion (P=0.012), grade (P=0.002) and relapse frequency (P=0.041).

CONCLUSIONS

The present study is the first to show a relationship between the genetic variation rs8100239 of BCL3 and cancer patients' survival. It also represents the first quantitative evaluation of BCL3 expression in NSCLC. Our findings indicate that rs8100239 may be considered as a novel prognostic indicator, demonstrating also the overexpression of BCL3 protein in NSCLC and implicating this pivotal molecule in the pathogenesis of NSCLC.

[Role of the Sonic Hedgehog pathway in thoracic cancers]

INTRODUCTION

Sonic Hedgehog (Shh) pathway is physiologically activated during embryogenesis and development. It plays a role in idiopathic lung fibrosis and is also activated in several solid cancers.

STATE OF THE ART

Shh pathway is reactivated in thoracic cancers, as small cell lung carcinoma, non-small cell lung carcinoma and malignant pleural mesothelioma. Shh pathway is associated with cancer stem cells and seems to have a crucial role in tumor proliferation, aggressiveness and chemoresistance in these cancers. This review describes the activation mode of Shh pathway in thoracic cancers and its role in small cell lung carcinoma, non-small cell lung carcinoma and malignant pleural mesothelioma, using in vitro and in vivo models. Notably, data from literature show that inhibition of Shh pathway has an antitumor action and sensitizes to chemotherapy.

PERSPECTIVES

These results incite to develop targeted therapies against Shh pathway in the treatment of thoracic cancers.

Effects and mechanisms of blocking the hedgehog signaling pathway in human gastric cancer cells

Excessive activation of the hedgehog (Hh) signaling pathway is important in a variety of human cancer cell types, including gastric cancer. However, the underlying mechanisms of the Hh signaling pathway in inducing gastric tumorigenesis and its downstream target genes are largely unknown. In the present study, the inhibitory effect of cyclopamine on the Hh signaling pathway was investigated in the human gastric cancer AGS cell line. It was identified that cyclopamine treatment inhibited the proliferation, migration and invasion of the AGS cells in a dose- and time-dependent manner, and resulted in the downregulation of a number of key Hh signaling pathway-associated factors [glioma-associated oncogene homolog 1, C-X-C chemokine receptor type 4 and transforming growth factor (TGF)-β1] at the RNA and protein levels. Furthermore, the secretion of TGF-β1 was significantly reduced following the administration of cyclopamine to the AGS cells. The results of the present study provided insight into the mechanisms by which the Hh signaling pathway regulates gastric cancer formation and identified the Hh signaling pathway as a potential novel therapeutic target in human gastric cancer.

Cooperative integration between HEDGEHOG-GLI signalling and other oncogenic pathways: implications for cancer therapy

The HEDGEHOG-GLI (HH-GLI) signalling is a key pathway critical in embryonic development, stem cell biology and tissue homeostasis. In recent years, aberrant activation of HH-GLI signalling has been linked to several types of cancer, including those of the skin, brain, lungs, prostate, gastrointestinal tract and blood. HH-GLI signalling is initiated by binding of HH ligands to the transmembrane receptor PATCHED and is mediated by transcriptional effectors that belong to the GLI family, whose activity is finely tuned by a number of molecular interactions and post-translation modifications. Several reports suggest that the activity of the GLI proteins is regulated by several proliferative and oncogenic inputs, in addition or independent of upstream HH signalling. The identification of this complex crosstalk and the understanding of how the major oncogenic signalling pathways interact in cancer is a crucial step towards the establishment of efficient targeted combinatorial treatments. Here we review recent findings on the cooperative integration of HH-GLI signalling with the major oncogenic inputs and we discuss how these cues modulate the activity of the GLI proteins in cancer. We then summarise the latest advances on SMO and GLI inhibitors and alternative approaches to attenuate HH signalling through rational combinatorial therapies.

Transcription factor glioma-associated oncogene homolog 1 is required for transforming growth factor-β1-induced epithelial-mesenchymal transition of non-small cell lung cancer cells

Epithelial-mesenchymal transition (EMT) is the process by which epithelial cells depolarize and acquire a mesenchymal phenotype, and is a common early step in the process of metastasis. Patients with lung cancer frequently already have distant metastases when they are diagnosed, highlighting the requirement for early and effective interventions to control metastatic disease. Transforming growth factor-β1 (TGF-β1) is able to induce EMT, however the molecular mechanism of this remains unclear. In the current study, TGF-β1 was reported to induce EMT and promote the migration of non-small cell lung cancer (NSCLC) cells. A notable observation was that EMT induction was accompanied by the upregulation of human glioma-associated oncogene homolog 1 (Gli1) mRNA and protein levels. Furthermore, Gli1 levels were depleted by small interfering RNA, and the Gli1 inhibitor GANT 61 attenuated the TGF-β1-mediated induction of EMT and cell migration. The results of the current study suggest that Gli1 regulates TGF-β1-induced EMT, which may provide a novel therapeutic target to inhibit metastasis in patients with NSCLC.

Targeting FoxM1 by thiostrepton inhibits growth and induces apoptosis of laryngeal squamous cell carcinoma

PURPOSE

We have previously reported that forkhead box M1 (FoxM1) transcription factor was overexpressed in laryngeal squamous cell carcinoma (LSCC) and was associated with development of LSCC. However, there are limited studies regarding the functional significance of FoxM1 and FoxM1 inhibitor thiostrepton in LSCC. Therefore, the aim of this study was to examine both in vitro and in vivo activity of FoxM1 inhibitor thiostrepton against LSCC cell line and nude mice.

METHODS

Cell viability was studied by CCK-8 assay. Cell growth was evaluated by CFSE staining and cell cycle analysis. Apoptosis was measured by flow cytometry. The mRNA and protein expression were detected by quantitative real-time RT-PCR, Western blot and immunohistochemical staining. Xenograft model of tumor formation was used to investigate how thiostrepton influences tumorigenesis in vivo.

RESULTS

Overexpression of FoxM1 in LSCC cells was down-regulated by thiostrepton in a dose-dependent manner. Thiostrepton caused dose- and time-dependent suppression of cell viability of LSCC. Moreover, thiostrepton induced cell cycle arrest at S phase at early time and inhibited DNA synthesis in LSCC cells in a dose- and time-dependent manner by down-regulation of cyclin D1 and cyclin E1. Thiostrepton also induced dose- and time-dependent apoptosis of LSCC cells by down-regulation of Bcl-2, up-regulation of Bax and p53, and inducing release of cytochrome c accompanied by activation of cleaved caspase-9, cleaved caspase-3 and cleaved PARP. In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented activation of cleavage caspase-3 and abrogates cell death induced by thiostrepton treatment. Furthermore, FADD and cleaved caspase-8 were activated, and expression of cIAP1, XIAP and survivin were inhibited by thiostrepton. Finally, treatment of LSCC cell line xenografts with thiostrepton resulted in tumorigenesis inhibition of tumors in nude mice by reducing proliferation and inducing apoptosis of LSCC cells.

CONCLUSIONS

Collectively, our finding suggest that targeting FoxM1 by thiostrepton inhibit growth and induce apoptosis of LSCC through mitochondrial- and caspase-dependent intrinsic pathway and Fas-dependent extrinsic pathway as well as IAP family. Thiostrepton may represent a novel lead compound for targeted therapy of LSCC.

CDO, an Hh-coreceptor, mediates lung cancer cell proliferation and tumorigenicity through Hedgehog signaling

Hedgehog (Hh) signaling plays essential roles in various developmental processes, and its aberrant regulation results in genetic disorders or malignancies in various tissues. Hyperactivation of Hh signaling is associated with lung cancer development, and there have been extensive efforts to investigate how to control Hh signaling pathway and regulate cancer cell proliferation. In this study we investigated a role of CDO, an Hh co-receptor, in non-small cell lung cancer (NSCLC). Inhibition of Hh signaling by SANT-1 or siCDO in lung cancer cells reduced proliferation and tumorigenicity, along with the decrease in the expression of the Hh components. Histological analysis with NSCLC mouse tissue demonstrated that CDO was expressed in advanced grade of the cancer, and precisely co-localized with GLI1. These data suggest that CDO is required for proliferation and survival of lung cancer cells via Hh signaling.

Overexpression of FOXM1 is associated with metastases of nasopharyngeal carcinoma

BACKGROUND

The forkhead box M1 (FOXM1) transcription factor plays an important role in the metastases of many cancers. Down-regulation of FOXM1 by its inhibitor, thiostrepton, can inhibit the metastatic potential of some cancers; however, there are few studies regarding the functional significance of FOXM1 and thiostrepton in the metastases of nasopharyngeal carcinoma (NPC) and the underlying mechanism.

METHODS

Expression of FOXM1 in NPC, normal nasopharyngeal tissues, a NPC cell line (C666-1), and a nasopharyngeal epithelial cell line (NP69) was investigated by immunohistochemical staining, qRT-PCR, and Western blot. The correlation between FOXM1 expression and the clinical characteristics of patients was analyzed. Moreover, the effects of thiostrepton on expression of FOXM1 in C666-1 and NP69 cells, and the invasion and migration ability of C666-1 cells were examined. The expressions of MMP-2, MMP-9, fascin-1, ezrin, and paxillin were determined after treatment with thiostrepton.

RESULTS

FOXM1 was overexpressed in NPC and C666-1 cells compared with normal nasopharyngeal tissues and NP69 cells. Overexpression of FOXM1 was associated with lymph node metastasis and advanced tumor stage. Moreover, thiostrepton inhibited expression of FOXM1 in C666-1 cells in a dose-dependent manner, but had a minimal effect on NP69 cells. Thiostrepton inhibited the migration and invasion ability of C666-1 cells by down-regulating the expression of MMP-2, MMP-9, fascin-1, and paxillin.

CONCLUSIONS

Overexpression of FOXM1 is associated with metastases of NPC patients. Thiostrepton inhibits the metastatic ability of NPC cells by down-regulating the expression of FOXM1, MMP-2, MMP-9, fascin-1, and paxillin.

Targeting the SMO oncogene by miR-326 inhibits glioma biological behaviors and stemness

BACKGROUND

Few studies have associated microRNAs (miRNAs) with the hedgehog (Hh) pathway. Here, we investigated whether targeting smoothened (SMO) with miR-326 would affect glioma biological behavior and stemness.

METHODS

To investigate the expression of SMO and miR-326 in glioma specimens and cell lines, we utilized quantitative real-time (qRT)-PCR, Western blot, immunohistochemistry, and fluorescence in situ hybridization. The luciferase reporter assay was used to verify the relationship between SMO and miR-326. We performed cell counting kit-8, transwell, and flow cytometric assays using annexin-V labeling to detect changes after transfection with siRNA against SMO or miR-326. qRT-PCR assays, neurosphere formation, and immunofluorescence were utilized to detect the modification of self-renewal and stemness in U251 tumor stem cells. A U251-implanted intracranial model was used to study the effect of miR-326 on tumor volume and SMO suppression efficacy.

RESULTS

SMO was upregulated in gliomas and was associated with tumor grade and survival period. SMO inhibition suppressed the biological behaviors of glioma cells. SMO expression was inversely correlated with miR-326 and was identified as a novel direct target of miR-326. miR-326 overexpression not only repressed SMO and downstream genes but also decreased the activity of the Hh pathway. Moreover, miR-326 overexpression decreased self-renewal and stemness and partially prompted differentiation in U251 tumor stem cells. In turn, the inhibition of Hh partially elevated miR-326 expression. Intracranial tumorigenicity induced by the transfection of miR-326 was reduced and was partially mediated by the decreased SMO expression.

CONCLUSIONS

This work suggests a possible molecular mechanism of the miR- 326/SMO axis, which can be a potential alternative therapeutic pathway for gliomas.

Expression of the GLI family genes is associated with tumor progression in advanced lung adenocarcinoma

BACKGROUND

The hedgehog (Hh) signaling pathway is aberrantly activated in various cancers. Expression of the GLI family of genes, which encode for transcriptional factors of the Hh pathway, has not been fully assessed in clinical samples of advanced lung adenocarcinoma. In this study, we retrospectively evaluated the expression of the GLI family of genes in advanced stage lung adenocarcinoma samples and determined their relation to patient survival.

METHODS

The levels of GLI1, GLI2, and GLI3 mRNA expression were measured by quantitative real-time polymerase chain reaction in surgically obtained tissue samples from stage II-IV lung adenocarcinoma patients (n = 102). Pairwise comparisons between all three GLI mRNA expression were performed, and after dichotomizing the patients into low and high expression groups according to each GLI mRNA expression level, survival curves were calculated and multivariate analyses were conducted.

RESULTS

Significant positive correlation was found between GLI1 and GLI3 mRNA expression (P <0.001). Tumors with higher expression (upper 15%) of GLI1 or GLI3 mRNA were associated with poor survival in stage II-IV (5-year overall survival rates: GLI1 mRNA low, 41.7% vs. high, 20.0%, P = 0.0074; GLI3 mRNA low, 43.1% vs. high, 13.3%, P = 0.0062) and stage III-IV (5-year overall survival rates: GLI1 mRNA low, 34.0% vs. high, 0%, P = 0.0012; GLI3 mRNA low, 33.4% vs. high, 7.7%, P = 0.057) lung adenocarcinoma patients. GLI2 mRNA expression did not appear to have great clinical significance. Multivariate analysis revealed higher GLI1 mRNA expression as an independent factor for unfavorable patient survival (P = 0.0030, hazard ratio = 3.1, 95% confidence interval = 1.5-6.2), as well as tumor differentiation and stage.

CONCLUSIONS

Expression of GLI1 and GLI3 mRNA was strongly correlated, and their overexpression, especially that of GLI1, was found to be predictive of aggressive tumor behavior. This study indicates that the Hh pathway may be a key oncogenic signaling network in tumor pathogenesis and, thus, a potential therapeutic target in advanced lung adenocarcinoma.