Gene Summary

Gene:GLI1; GLI family zinc finger 1
Aliases: GLI, PPD1, PAPA8
Summary:This gene encodes a member of the Kruppel family of zinc finger proteins. The encoded transcription factor is activated by the sonic hedgehog signal transduction cascade and regulates stem cell proliferation. The activity and nuclear localization of this protein is negatively regulated by p53 in an inhibitory loop. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2009]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:zinc finger protein GLI1
Source:NCBIAccessed: 31 August, 2019

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (9)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Skin, Basal Cell CarcinomaGLI1 and Basal Cell Carcinoma (BCC) - Skin View Publications58
Pancreatic CancerGLI1 and Pancreatic Cancer View Publications50
MedulloblastomaGLI1 and Medulloblastoma View Publications40
Stomach CancerGLI1 and Stomach Cancer View Publications29
Ewing's SarcomaGLI1 upregulation by EWSR1/FLI1 in Ewing's Sarcoma
Zwerne et al (2008) reported that EWS/FLI1 fusion produces transcriptional upregulation of GLI1 and its direct transcriptional target PATCHED1 in a model transformation system. Joo et al (2009) found that several known EWS/FLI1 targets appear to be targeted through GLI1 suggesting a central role for GLI1 in the pathogenesis of Ewing Tumours.
View Publications7
Cervical CancerGLI1 and Cervical Cancer View Publications6
Breast CancerGLI1 and Breast Cancer View Publications35
Lung CancerGLI1 and Lung Cancer View Publications30

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: GLI1 (cancer-related)

Sun W, Li L, Du Z, et al.
Combination of phospholipase Cε knockdown with GANT61 sensitizes castration‑resistant prostate cancer cells to enzalutamide by suppressing the androgen receptor signaling pathway.
Oncol Rep. 2019; 41(5):2689-2702 [PubMed] Free Access to Full Article Related Publications
Castration‑resistant prostate cancer (CRPC) is a major challenge in the treatment of prostate cancer (PCa). Phospholipase Cε (PLCε), an oncogene, has been found to be involved in the carcinogenesis, tumor proliferation and migration of several types of cancer. The effects, however, of PLCε on CRPC remains unclear. In the present study, the expression of PLCε and glioma‑associated homolog (Gli)‑1/Gli‑2 in benign prostatic hyperplasia (BPH), PCa and CRPC tissues and cells was investigated, and the correlations between PLCε and Gli‑1/Gli‑2 in CRPC tissues and cell lines were further explored. In addition, the effect of PLCε on cell proliferation and invasion was assessed in CRPC cell lines, and the sensitivity of EN‑R and 22RV1 cells to enzalutamide following the downregulation of PLCε expression was determined using lentivirus‑mediated shPLCε and/or treatment with specific Gli inhibitor GANT61. It was found that the PLCε expression was excessively upregulated in the majority of CRPC tissues, and PLCε positivity was linked to poor progression‑free survival (PFS) and overall survival (OS) in patients with PCa. Furthermore, PLCε knockdown significantly suppressed CRPC cell proliferation and invasion. Of note, it was found that PLCε knockdown increased the sensitivity of CRPC cells to enzalutamide in vitro by suppressing androgen receptor (AR) activities via the non‑canonical Hedgehog/Gli‑2 and p‑STAT3 signaling pathways. PLCε knockdown was shown to increase the sensitivity of CRPC cell xenografts to enzalutamide in vivo. Finally, the combination of PLCε knockdown with GANT61 significantly sensitized CRPC cells to enzalutamide. Collectively, the results of the present study suggest that PLCε is a potential therapeutic target for CRPC.

Yao Y, Zhou D, Shi D, et al.
GLI1 overexpression promotes gastric cancer cell proliferation and migration and induces drug resistance by combining with the AKT-mTOR pathway.
Biomed Pharmacother. 2019; 111:993-1004 [PubMed] Related Publications
Hedgehog (HH) pathway significantly affected the pathogenesis of Gastric cancer (GC), but the multiple uncanonical HH pathways that are mediated by Zinc Finger protein GLI1 (GLI1) are still unclear. In the present work, we evaluated GLI1 and p-AKT expression in GC using immunohistochemistry (IHC) analysis. GLI1 and AKT specific shRNA was transfected into GC cell lines to investigate the cross-regulation between HH pathway and AKT-mTOR pathway. The effect of GLI1 and p-AKT on proliferation, migration, and drug resistance were examined. Moreover, a mouse xenograft model of GC was established to verify the role of GLI1 and p-AKT in promoting drug sensitivity in vivo. Our results suggested the clinicopathological factors and prognosis by the differential expression of GLI1 and p-AKT in GC patients. GLI1 was activated by the AKT-mTOR pathway. Co-expression of GLI1 and p-AKT was associated with cell viability, migration, and drug resistance and indicated a poor prognosis in GC patients. Agents targeted against both GLI1 and p-AKT may reverse drug-resistance and achieve better inhibition than agents targeted against a single molecule. There was a significant correlation between the high expression of GLI1 and p-AKT in GC. Additionally, our study confirmed the activity of the AKT-mTOR-GLI1 axis, which provided a new viable field for GC treatment.

Hu YT, Li BF, Zhang PJ, et al.
Dbx2 exhibits a tumor-promoting function in hepatocellular carcinoma cell lines
World J Gastroenterol. 2019; 25(8):923-940 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. HCC patients suffer from a high mortality-to-incidence ratio and low cure rate since we still have no specific and effective treatment. Although tremendous advances have been made in the investigation of HCC, the specific mechanisms of the progression of this disease are still only partially established. Hence, more research is needed to elucidate the underlying potential mechanisms to develop effective strategies for HCC.
AIM: To determine the role of developing brain homeobox 2 (Dbx2) gene in promoting the development of HCC.
METHODS: Dbx2 expression in clinical specimens and HCC cell lines was detected by Western blot (WB) and immunohistochemistry. Gain and loss of Dbx2 function assays were performed
RESULTS: Compared to matched adjacent non-tumorous tissues, Dbx2 was overexpressed in 5 HCC cell lines and 76 surgically resected HCC tissues. Dbx2 overexpression was correlated with large tumor size. Both gain and loss of function assays indicated that Dbx2 promoted HCC cell proliferation by facilitating the transition from G1 to S phase, attenuating apoptosis and promoted HCC proliferation, migration, and invasion
CONCLUSION: Our results indicate that Dbx2 is significantly upregulated in HCC tissues and plays significant roles in proliferation and metastasis of HCC cells by activating the Shh pathway.

Fu J, Shrivastava A, Shrivastava SK, et al.
Triacetyl resveratrol upregulates miRNA‑200 and suppresses the Shh pathway in pancreatic cancer: A potential therapeutic agent.
Int J Oncol. 2019; 54(4):1306-1316 [PubMed] Related Publications
Trans‑3,4',5‑trihydroxystilbene (resveratrol) is a naturally occurring polyphenolic phytoalexin with marked anticancer activities, and is mainly found in grapes, berries and peanuts. However, due to a low bioavailability, it has not progressed to clinical practice for cancer treatment. Therefore, the aims of the present study were to examine the anticancer activities of the resveratrol derivative, triacetyl resveratrol (TCRV), in pancreatic cancer cells. Apoptosis was measured by fluorescence‑activated cell sorting and terminal deoxynucleotidyl transferase (TdT)‑mediated dUTP nick‑end labeling assays. Gene expression was measured by reverse transcription‑quantitative polymerase chain reaction. TCRV inhibited colony formation and induced apoptosis through caspase‑3 activation in human pancreatic cancer AsPC‑1 and PANC‑1 cells, whereas it exerted no effect on human pancreatic normal ductal epithelial cells (HPNE). TCRV inhibited epithelial‑mesenchymal transition (EMT) by upregulating the expression of E‑cadherin and suppressing the expression of N‑cadherin and the transcription factors, Snail, Slug and Zeb1. TCRV inhibited Zeb1 3'UTR‑luciferase activity through the upregulation of microRNA (miR)‑200 family members. The inhibitory effects of TCRV on pancreatic cancer cell migration and invasion were counteracted by anti‑miR‑200 family members. The inhibitory effects of TCRV on EMT and the induction of apoptosis were exerted through the suppression of the sonic hedgehog (Shh) pathway, and through the modulation of cyclin D1 and Bcl‑2 expression. The hyperactivation of the Shh pathway by either Shh protein or Gli1 overexpression abrogated the biological effects of TCRV. Taken together, the results of this study demonstrate that TCRV inhibits pancreatic cancer growth and EMT by targeting the Shh pathway and its downstream signaling mediators. TCRV inhibited EMT through the upregulation of miR‑200 family members. Since TCRV effectively inhibited the growth of human pancreatic cancer cells by modulating the Shh pathway, without affecting the growth of HPNE cells, our findings suggest the possible use of TCRV as a promising candidate for the treatment and/or prevention of pancreatic cancer.

Lin J, Tan H, Nie Y, et al.
Krüppel-like factor 2 inhibits hepatocarcinogenesis through negative regulation of the Hedgehog pathway.
Cancer Sci. 2019; 110(4):1220-1231 [PubMed] Free Access to Full Article Related Publications
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The most important reason for the occurrence of HCC is hepatitis C or B infection. Moreover, genetic factors play an important role in the tumorigenesis of HCC. Here, we demonstrated that Krüppel-like factor 2 (KLF2) expression was downregulated in HCC samples compared with adjacent tissues. Additionally, KLF2 was shown to inhibit the growth, migration and colony-formation ability of liver cancer cells. Further mechanistic studies revealed that KLF2 can compete with Gli1 for interaction with HDAC1 and restrains Hedgehog signal activation. Together, our results suggest that KLF2 has potential as a diagnostic biomarker and therapeutic target for the treatment of HCC.

Zhang M, Tan S, Yu D, et al.
Triptonide inhibits lung cancer cell tumorigenicity by selectively attenuating the Shh-Gli1 signaling pathway.
Toxicol Appl Pharmacol. 2019; 365:1-8 [PubMed] Related Publications
Lung cancer is a leading lethal disease with a 5-year survival rate of only 16%. Inadequate potent anti-cancer drugs appear to be a bottleneck in the treatment of lung cancer; hence, how to develop effective anti-lung cancer therapeutics is an urgent problem. In this study, we aim to explore a novel compound with potent anti-lung cancer effect and study its anti-cancer mechanisms. We found that triptonide at very low concentrations of 5-10 nM caused a marked suppression of cell proliferation and colony formation of lung cancer cells. More interestingly, triptonide also robustly inhibited the lung cancer cell formation of tumor spheres, and reduced the stemness and tumorigenicity of the sphere-forming cells. In vivo studies showed that administration of triptonide significantly inhibited the tumor growth with low toxicity. Molecular mechanistic studies revealed that triptonide significantly decreased expression of the Gli1 at both mRNA and protein levels by repressing Gli1 gene promoter activity. Additionally, triptonide reduced the levels of cancer stem cell key signaling protein sonic hedgehog (Shh), but increased the amount of Ptch1, a protein binding to SMO to diminish the Shh signal transduction, thus inhibition of the Shh-Gli1 signaling pathway. Together, our findings show that triptonide effectively inhibits lung cancer cell growth, stemness, and tumorigenicity, and support the notion that triptonide is a new Shh-Gli1 signaling inhibitor and a novel anti-lung cancer drug candidate for further developing effective lung cancer therapeutics.

Wu L, Xia J, Yang J, et al.
Circ-ZNF609 promotes migration of colorectal cancer by inhibiting Gli1 expression via microRNA-150.
J BUON. 2018 Sep-Oct; 23(5):1343-1349 [PubMed] Related Publications
PURPOSE: To investigate the effect of circular (circ)-ZNF609 on the pathogenesis of colorectal cancer and its underlying mechanism.
METHODS: 24 cases of postoperative colorectal cancer tissues and 36 cases of mucosa tissues were selected as experimental group and control group, respectively. Circ-ZNF609 expression in colorectal cancer tissues and mucosa tissues were detected by quantitative real-time PCR (qRT-PCR). For in vitro experiments, subcellular localization of Circ-ZNF609 in nuclear and cytoplasmic HCT116 cells was assessed. MicroRNA-150 was found to bind to Circ-ZNF609 by dual luciferase reporter assay. Furthermore, migration ability of transfected HCT116 cells was assessed by Transwell assay. Additionally, mRNA and protein levels of glioma-associated oncogene 1 (Gli1) in HCT116 cells were detected by qRT-PCR and Western blot, respectively.
RESULTS: Higher expressions of Circ-ZNF609 and Gli1 were found in colorectal cancer tissues compared to paracancerous tissues. MicroRNA-150 was downregulated in colorectal cancer tissues. Pearson correlation analysis showed that Circ-ZNF609 was positively correlated with Gli1, and microRNA-150 was negatively correlated with Circ-ZNF609 and Gli1. Dual luciferase reporter assay confirmed that microRNA-150 was bound with cytoplasmic Circ-ZNF609. Furthermore, downregulated Circ-ZNF609 inhibited migration of HCT116 cells. In addition, knockdown of Circ-ZNF609 or overexpression of microRNA-150 inhibited cell migration, which was reversed by co-transfection with microRNA-150 inhibitor and Circ-ZNF609 siRNA.
CONCLUSIONS: Circ-ZNF609 regulates Gli1 expression via microRNA-150, thus affecting the migration of colorectal cancer.

Yin WC, Satkunendran T, Mo R, et al.
Dual Regulatory Functions of SUFU and Targetome of GLI2 in SHH Subgroup Medulloblastoma.
Dev Cell. 2019; 48(2):167-183.e5 [PubMed] Related Publications
SUFU alterations are common in human Sonic Hedgehog (SHH) subgroup medulloblastoma (MB). However, its tumorigenic mechanisms have remained elusive. Here, we report that loss of Sufu alone is unable to induce MB formation in mice, due to insufficient Gli2 activation. Simultaneous loss of Spop, an E3 ubiquitin ligase targeting Gli2, restores robust Gli2 activation and induces rapid MB formation in Sufu knockout background. We also demonstrated a tumor-promoting role of Sufu in Smo-activated MB (∼60% of human SHH MB) by maintaining robust Gli activity. Having established Gli2 activation as a key driver of SHH MB, we report a comprehensive analysis of its targetome. Furthermore, we identified Atoh1 as a target and molecular accomplice of Gli2 that activates core SHH MB signature genes in a synergistic manner. Overall, our work establishes the dual role of SUFU in SHH MB and provides mechanistic insights into transcriptional regulation underlying Gli2-mediated SHH MB tumorigenesis.

Antonucci L, Di Magno L, D'Amico D, et al.
Mitogen-activated kinase kinase kinase 1 inhibits hedgehog signaling and medulloblastoma growth through GLI1 phosphorylation.
Int J Oncol. 2019; 54(2):505-514 [PubMed] Free Access to Full Article Related Publications
The aberrant activation of hedgehog (HH) signaling is a leading cause of the development of medulloblastoma, a pediatric tumor of the cerebellum. The FDA‑approved HH inhibitor, Vismodegib, which targets the transmembrane transducer SMO, has shown limited efficacy in patients with medulloblastoma, due to compensatory mechanisms that maintain an active HH‑GLI signaling status. Thus, the identification of novel actionable mechanisms, directly affecting the activity of the HH‑regulated GLI transcription factors is an important goal for these malignancies. In this study, using gene expression and reporter assays, combined with biochemical and cellular analyses, we demonstrate that mitogen‑activated kinase kinase kinase 1 (MEKK1), the most upstream kinase of the mitogen‑activated protein kinase (MAPK) phosphorylation modules, suppresses HH signaling by associating and phosphorylating GLI1, the most potent HH‑regulated transcription factor. Phosphorylation occurred at multiple residues in the C‑terminal region of GLI1 and was followed by an increased association with the cytoplasmic proteins 14‑3‑3. Of note, the enforced expression of MEKK1 or the exposure of medulloblastoma cells to the MEKK1 activator, Nocodazole, resulted in a marked inhibitory effect on GLI1 activity and tumor cell proliferation and viability. Taken together, the results of this study shed light on a novel regulatory mechanism of HH signaling, with potentially relevant implications in cancer therapy.

Qin T, Li B, Feng X, et al.
Abnormally elevated USP37 expression in breast cancer stem cells regulates stemness, epithelial-mesenchymal transition and cisplatin sensitivity.
J Exp Clin Cancer Res. 2018; 37(1):287 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Recent studies have indicated that deubiquitinating enzymes (DUBs) are related to the stem-cell pathway network and chemo-resistance in cancer. Ubiquitin-specific peptidase 37 (USP37), a novel DUB, was identified to be a potential factor associated with tumor progression. However, the biological functions of USP37 in breast cancer remain unclear.
METHODS: The distribution of USP37 expression in breast cancer and the correlation between USP37 expression and the overall survival rate were detected by The Cancer Genome Atlas (TCGA) database. Gene set enrichment analysis (GSEA) was utilized to evaluate potential mechanism of USP37 in breast cancer. The USP37 expression in breast cancer tissues and breast cancer cell lines were detected by immunohistochemistry and western blotting. Sorting of breast cancer stem cells (BCSCs) were by using MACS assay. In vitro and in vivo assays were performed to examine the biological functions of USP37 in breast cancer cells. MG132, CHX chase, immunofluorescence staining and co-immunoprecipitation assays were used to test the interaction between USP37 and Gli-1.
RESULTS: Bioinformatics analysis demonstrated that USP37 gene was elevated in breast cancer tissues and its overexpression was strongly correlated with the increased mortality rate. GSEA analysis showed that USP37 expression was positively associated with cell growth and metastasis while negatively related to cell apoptosis in the TCGA breast cancer samples. USP37 expression was elevated in breast cancer tissues and breast cancer cell lines. Moreover, we also detected that USP37 was overexpressed in BCSCs. USP37 regulated the ability of cell invasion, epithelial-mesenchymal transition (EMT), stemness and cisplatin sensitivity in breast cancer cell lines. Additionally, USP37 knockdown inhibited tumorigenicity and increased anticancer effect of cisplatin in vivo. Knockdown of USP37 significantly decreased hedgehog (Hh) pathway components Smo and Gli-1. Gli-1 was stabilized by USP37 and they interacted with each other. Further studies indicated that USP37 knockdown could inhibit the stemness, cell invasion and EMT in breast cancer via downregulation of Hh pathway.
CONCLUSIONS: These findings reveal that USP37 is highly expressed in BCSCs and is correlated with poor prognosis in breast cancer patients. USP37 can regulate the stemness, cell invasion and EMT via Hh pathway, and decreased USP37 confers sensitivity to cisplatin in breast cancer cells. USP37 is required for the regulation of breast cancer progression, as well as a critical target for clinical treatment of breast cancer.

Yang Y, Bhosle SR, Yu YH, et al.
Tumidulin, a Lichen Secondary Metabolite, Decreases the Stemness Potential of Colorectal Cancer Cells.
Molecules. 2018; 23(11) [PubMed] Free Access to Full Article Related Publications
Lichens produce various unique chemicals that are used in the pharmaceutical industry. To screen for novel lichen secondary metabolites that inhibit the stemness potential of colorectal cancer cells, we tested acetone extracts of 11 lichen samples collected in Chile. Tumidulin, isolated from

Okuhashi Y, Itoh M, Tohda S
Anticancer Res. 2018; 38(11):6329-6332 [PubMed] Related Publications
BACKGROUND: Hedgehog (HH), WNT, NOTCH, and mechanistic target of rapamycin (mTOR) signalling pathways are known to regulate the progression of cancer; however, their interaction in leukaemia cells is not fully clarified.
MATERIALS AND METHODS: Myeloid and T-lymphoblastic leukaemia cell lines (NB4, THP-1, Jurkat, and DND-41) were transfected with small interfering RNAs targeting the glioma-associated oncogene homolog 1 (GLI1) and catenin beta-1 (CTNNB1) genes involved in the regulation of HH and WNT pathways, respectively, and we examined cell proliferation and gene expression.
RESULTS: The knockdown of GLI1 and CTNNB1 did not significantly affect proliferation of any cell line; however, it up-regulated the expression of NOTCH1, cleaved NOTCH1 fragment, and phosphorylated mTOR in NB4 cells, but not in the other cell lines.
CONCLUSION: Our data suggest that HH and WNT act upstream of NOTCH and mTOR pathways and negatively regulate them in myeloid NB4 cells. Further studies are required to determine the biological significance of this signalling crosstalk in leukaemia.

Jia Y, Gu D, Wan J, et al.
The role of GLI-SOX2 signaling axis for gemcitabine resistance in pancreatic cancer.
Oncogene. 2019; 38(10):1764-1777 [PubMed] Free Access to Full Article Related Publications
Pancreatic cancer, mostly pancreatic ductal adenocarcinomas (PDAC), is one of the most lethal cancers, with a dismal median survival around 8 months. PDAC is notoriously resistant to chemotherapy. Thus far, numerous attempts using novel targeted therapies and immunotherapies yielded limited clinical benefits for pancreatic cancer patients. It is hoped that delineating the molecular mechanisms underlying drug resistance in pancreatic cancer may provide novel therapeutic options. Using acquired gemcitabine resistant pancreatic cell lines, we revealed an important role of the GLI-SOX2 signaling axis for regulation of gemcitabine sensitivity in vitro and in animal models. Down-regulation of GLI transcriptional factors (GLI1 or GLI2), but not SMO signaling inhibition, reduces tumor sphere formation, a characteristics of tumor initiating cell (TIC). Down-regulation of GLI transcription factors also decreased expression of TIC marker CD24. Similarly, high SOX2 expression is associated with gemcitabine resistance whereas down-regulation of SOX2 sensitizes pancreatic cancer cells to gemcitabine treatment. We further revealed that elevated SOX2 expression is associated with an increase in GLI1 or GLI2 expression. Our ChIP assay revealed that GLI proteins are associated with a putative Gli binding site within the SOX2 promoter, suggesting a more direct regulation of SOX2 by GLI transcription factors. The relevance of our findings to human disease was revealed in human cancer specimens. We found that high SOX2 protein expression is associated with frequent tumor relapse and poor survival in stage II PDAC patients (all of them underwent gemcitabine treatment), indicating that reduced SOX2 expression or down-regulation of GLI transcription factors may be effective in sensitizing pancreatic cancer cells to gemcitabine treatment.

Huang C, Lu H, Li J, et al.
SOX2 regulates radioresistance in cervical cancer via the hedgehog signaling pathway.
Gynecol Oncol. 2018; 151(3):533-541 [PubMed] Related Publications
OBJECTIVE: Resistance to radiotherapy accounts for most treatment failures in cervical cancer patients who receive radical radiation therapy. To discover the possible mechanism of radioresistance and improve the 5-year survival rate, we focused on how sex-determining region Y-box 2 (SOX2) mediates radioresistance in cervical cancer as well as on the interaction between SOX2 and the hedgehog (Hh) signaling pathway in this study.
METHODS: We established the acquired radioresistant subclone cells Hela-RR and Siha-RR. RT-qPCR, Western blot analysis, IHC, clonogenic survival assay, CCK-8 assay, apoptosis analysis, cell cycle analysis and xenograft models were used to explore the relationship between SOX2 expression and radiation resistance and to determine how SOX2 mediates radioresistance in cervical cancer. Furthermore, luciferase reporter and ChIP-PCR assays were utilized to assess the interaction between SOX2 and the Hh signaling pathway.
RESULTS: Our research suggested that high expression of SOX2 was responsible for radioresistance in cervical cancer. SOX2 was observed to be closely related to irradiation-induced survival, proliferation, apoptosis, and cell cycle changes. The Hh signaling pathway was found to be activated in Hela-RR and Siha-RR, and the activation changed with SOX2 expression. IHC staining of SOX2 and Gli1 showed a close relationship between SOX2 and the Hh pathway. Luciferase reporter and ChIP-PCR assays demonstrated that SOX2 interacted with the Hh signaling pathway by occupying the HHAT promoter.
CONCLUSIONS: SOX2 is a potential therapeutic target of irradiation resistance in cervical cancer. It mediates radioresistance in cervical cancer via the Hh signaling pathway.

Huang D, Wang Y, Xu L, et al.
GLI2 promotes cell proliferation and migration through transcriptional activation of ARHGEF16 in human glioma cells.
J Exp Clin Cancer Res. 2018; 37(1):247 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The Hedgehog (Hh) signaling pathway plays critical roles in modulating embryogenesis and maintaining tissue homeostasis, with glioma-associated oncogene (GLI) transcription factors being the main mediators. Aberrant activation of this pathway is associated with various human malignancies including glioblastoma, although the mechanistic details are not well understood.
METHODS: We performed a microarray analysis of genes that are differentially expressed in glioblastoma U87 cells overexpressing GLI2A, the active form of GLI2, relative to the control cells. Chromatin immunoprecipitation and dual-luciferase assays were used to determine whether Rho guanine nucleotide exchange factor 16 (ARHGEF16) is a downstream target of GLI2. Then, transwell migration, EdU and soft-agar colony formation assays were employed to test effects of ARHGEF16 on glioma cancer cell migration and proliferation, and the effects of GLI2/ARHGEF16 signaling on tumor growth were examined in vivo. Finally, we performed yeast two-hybrid assay, Co-IP and GST-pull down to identify factors that mediate effects of ARHGEF16.
RESULTS: We found that ARHGEF16 mRNA level was upregulated in U87 cells overexpressing GLI2A relative to control cells. GLI2 binds to the ARHGEF16 promoter and activates gene transcription. Glioma cells U87 and U118 overexpressing ARHGEF16 showed enhanced migration and proliferation relative to the control cells, while knockdown of ARHGEF16 in H4 cells led to decreased cell proliferation compared to the control H4 cells. In contrast to the promoting effect of GLI2A overexpression on glioma xenograft growth, both GLI2 inhibition and ARHGEF16 knockdown retarded tumor growth. Cytoskeleton-associated protein 5 (CKAP5) was identified as an interaction protein of ARHGEF16, which is important for the stimulatory effects of ARHGEF16 on glioma cell migration and proliferation.
CONCLUSIONS: These results suggest that therapeutic strategies targeting the GLI2/ARHGEF16/CKAP5 signaling axis could inhibit glioma progression and recurrence.

Yu Y, Cheng L, Yan B, et al.
Overexpression of Gremlin 1 by sonic hedgehog signaling promotes pancreatic cancer progression.
Int J Oncol. 2018; 53(6):2445-2457 [PubMed] Free Access to Full Article Related Publications
Sonic hedgehog (SHH) signaling is an important promotor of desmoplasia, a critical feature in pancreatic cancer stromal reactions involving the activation of pancreatic stellate cells (PSCs). Gremlin 1 is widely overexpressed in cancer-associated stromal cells, including activated PSCs. In embryonic development, SHH is a potent regulator of Gremlin 1 through an interaction network. This subtle mechanism in the cancer microenvironment remains to be fully elucidated. The present study investigated the association between Gremlin 1 and SHH, and the effect of Gremlin 1 in pancreatic cancer. The expression of Gremlin 1 in different specimens was measured using immunohistochemistry. The correlations among clinicopathological features and levels of Gremlin 1 were evaluated. Primary human PSCs and pancreatic cancer cell lines were exposed to SHH, cyclopamine, GLI family zinc finger-1 (Gli-1) small interfering RNA (siRNA), and Gremlin 1 siRNA to examine their associations and effects using an MTT assay, reverse transcription-quantitative polymerase chain reaction analysis, western blot analysis, and migration or invasion assays. The results revealed the overexpression of Gremlin 1 in pancreatic cancer tissues, mainly in the stroma. The levels of Gremlin 1 were significantly correlated with survival rate and pT status. In addition, following activation of the PSCs, the expression levels of Gremlin 1 increased substantially. SHH acts as a potent promoter of the expression of Gremlin 1, and cyclopamine and Gli-1 siRNA modulated this effect. In a screen of pancreatic cancer cell lines, AsPC-1 and BxPC-3 cells expressed high levels of Gremlin 1, but only AsPC-1 cells exhibited a high expression level of SHH. The results of the indirect co-culture experiment suggested that paracrine SHH from the AsPC-1 cells induced the expression of Gremlin 1 in the PSCs. Furthermore, Gremlin 1 siRNA negatively regulated the proliferation and migration of PSCs, and the proliferation, invasion and epithelial-mesenchymal transition of AsPC-1 and BxPC-3 cells. Based on the data from the present study, it was concluded that an abnormal expression level of Gremlin 1 in pancreatic cancer was induced by SHH signaling, and that the overexpression of Gremlin 1 enabled pancreatic cancer progression.

Melamed JR, Ioele SA, Hannum AJ, et al.
Polyethylenimine-Spherical Nucleic Acid Nanoparticles against Gli1 Reduce the Chemoresistance and Stemness of Glioblastoma Cells.
Mol Pharm. 2018; 15(11):5135-5145 [PubMed] Free Access to Full Article Related Publications
Glioblastoma (GBM) is the most common and lethal primary brain tumor in adults, with nearly 100% of patients ultimately succumbing to the disease. Median patient survival is 15 months, and no standard of care currently exists for recurrent cases. Glioma stem cells (GSCs), a rare and highly aggressive subpopulation of cells within these tumors, have recently emerged as drivers of tumor initiation and recurrence, and a growing body of evidence suggests that they must be completely eradicated to prevent relapse. Toward this goal, we have developed polyethylenimine-wrapped spherical nucleic acid nanoparticles (PEI-SNAs) targeting Gli1, a transcription factor within the Hedgehog signaling pathway that is crucial for the maintenance of GSCs. Here, we demonstrate that Gli1 PEI-SNAs bind scavenger receptors on GBM cells to undergo endocytosis in a caveolae/lipid raft/dynamin-dependent manner. They further achieve ∼30% silencing of tumor-promoting Hedgehog pathway genes and downstream target genes that promote the aggressive, chemoresistant phenotype of GBM. This produces a 30% decrease in proliferation that correlates with a robust onset of GBM cell senescence as well as an ∼60% decrease in metabolic activity with or without cotreatment with temozolomide (TMZ), the frontline chemotherapy for GBM. Most importantly, Gli1 PEI-SNAs impair the self-renewal capacity of GBM cells as indicated by a 30-40% reduction in the expression of stemness genes and further impair the formation of stem-like neurospheres. They also substantially improve neurosphere chemosensitivity as demonstrated by a 2-fold increase in the fraction of cells undergoing apoptosis in response to low doses of TMZ. These results underscore the potential for siRNA therapeutics targeting Gli1 to reduce GBM resistance to therapy and warrant further development of PEI-SNAs and Gli1-targeted therapies to alleviate drug resistance and recurrence for GBM patients.

Zhou P, Cao Y, Liu X, et al.
Delivery siRNA with a novel gene vector for glioma therapy by targeting Gli1.
Int J Nanomedicine. 2018; 13:4781-4793 [PubMed] Free Access to Full Article Related Publications
Background: Gene therapy has recently shown considerable clinical benefit in cancer therapy during the past few years, and the application of this choice in cancer treatments is increasing continually. Gli1 is an ideal candidate target for cancer gene therapy and is important for tumorigenesis.
Methods: In this study, we developed a novel gene delivery system with a self-assembly method by using a 1,2-dioleoyl-3-trimethylammonium-propane and methoxy poly (ethylene glycol)-poly(lactide) copolymer (DMP), with zeta potential of 32.7 mV and measuring 35.6 nm. The effect of this delivery system was tested in vitro and in vivo.
Results: DMP showed good performance in delivering siRNA to glioma cells in vitro with high transfection performance (98%). Moreover, DMP-Gli1si shows a satisfactory anti-glioma effect via induction of cell apoptosis and cell growth inhibition in vitro. Furthermore, for subcutaneous tumor-bearing mice, treatment with the DMP-Gli1si complex significantly inhibited tumor growth by inhibiting Gli1 protein expression, promoting apoptosis, and reducing proliferation.
Conclusion: The complex of Gli1 siRNA and DMP may potentially play an important role as a new drug in the clinical treatment of gliomas.

Réda J, Vachtenheim J, Vlčková K, et al.
Widespread Expression of Hedgehog Pathway Components in a Large Panel of Human Tumor Cells and Inhibition of Tumor Growth by GANT61: Implications for Cancer Therapy.
Int J Mol Sci. 2018; 19(9) [PubMed] Free Access to Full Article Related Publications
The sonic Hedgehog/GLI signaling pathway (HH) is critical for maintaining tissue polarity in development and contributes to tumor stemness. Transcription factors GLI1⁻3 are the downstream effectors of HH and activate oncogenic targets. To explore the completeness of the expression of HH components in tumor cells, we performed a screen for all HH proteins in a wide spectrum of 56 tumor cell lines of various origin using Western blot analysis. Generally, all HH proteins were expressed. Important factors GLI1 and GLI2 were always expressed, only exceptionally one of them was lowered, suggesting the functionality of HH in all tumors tested. We determined the effect of a GLI inhibitor GANT61 on proliferation in 16 chosen cell lines. More than half of tumor cells were sensitive to GANT61 to various extents. GANT61 killed the sensitive cells through apoptosis. The inhibition of reporter activity containing 12xGLI consensus sites by GANT61 and cyclopamine roughly correlated with cell proliferation influenced by GANT61. Our results recognize the sensitivity of tumor cell types to GANT61 in cell culture and support a critical role for GLI factors in tumor progression through restraining apoptosis. The use of GANT61 in combined targeted therapy of sensitive tumors, such as melanomas, seems to be immensely helpful.

Zhang C, Kang Y, Ma R, et al.
Expression of Numb and Gli1 in malignant pleural mesothelioma and their clinical significance.
J Cancer Res Ther. 2018 Jul-Sep; 14(5):970-976 [PubMed] Related Publications
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.

Essid N, Chambard JC, Elgaaïed AB
Induction of epithelial-mesenchymal transition (EMT) and Gli1 expression in head and neck squamous cell carcinoma (HNSCC) spheroid cultures.
Bosn J Basic Med Sci. 2018; 18(4):336-346 [PubMed] Free Access to Full Article Related Publications
Tumor microenvironment provides a specialized niche in which a population of stem-like cells is enriched and contributes to cancer progression. Moreover, cancer stem cell (CSC) phenotype has been associated with epithelial-mesenchymal transition (EMT). Here we investigated the effect of tumor microenvironment on the phenotypic characteristics of head and neck cancer cells and expression of CSC markers using a three-dimensional (3D), spheroid, culture system of CAL33 cell line from human tongue squamous cell carcinoma. CAL33 cells derived from 2D monolayer cultures were grown in spheroid cultures containing serum-free medium (epidermal growth factor [EGF], fibroblast growth factor [FGF], and insulin). Adherent CAL33 cells from spheroids or standard control cultures were grown in the presence/absence of serum in combination with hypoxia/normoxia. Markers of EMT, CSC, and hypoxia were analyzed either by Western blotting, immunofluorescence, or reverse transcription quantitative PCR. Spheroid cultures showed hypoxic microenvironment (high carbonic anhydrase IX [CAIX] expression), mesenchymal-like characteristics (reduced E-cadherin and increased vimentin and N-cadherin expression, presence of larger colonies comprised of larger, spread cells with lower density), and increased expression of the CSC marker glioma-associated oncogene homolog 1 (Gli1). These effects were recapitulated in serum-free adherent CAL33 cells maintained for prolonged periods in hypoxia (1% O2) but, in contrast, were completely abolished by the presence of serum. Overall, we found that a combination of hypoxia, EGF and FGF was essential to induce the EMT in adherent CAL33 cell cultures. The addition of serum rapidly reverts the EMT of cells, affects CSC phenotype and, thus, prevents the detection of such cells in tumor cell lines.

Lau BW, Huh K, Madero-Marroquin R, et al.
Hedgehog/GLI1 activation leads to leukemic transformation of myelodysplastic syndrome in vivo and GLI1 inhibition results in antitumor activity.
Oncogene. 2019; 38(5):687-698 [PubMed] Free Access to Full Article Related Publications
Myelodysplastic syndromes (MDSs) are stem cell disorders with risk of transformation to acute myeloid leukemia (AML). Gene expression profiling reveals transcriptional expression of GLI1, of Hedgehog (Hh) signaling, in poor-risk MDS/AML. Using a murine model of MDS we demonstrated that constitutive Hh/Gli1 activation accelerated leukemic transformation and decreased overall survival. Hh/Gli1 activation resulted in clonal expansion of phenotypically defined granulocyte macrophage progenitors (GMPs) and acquisition of self-renewal potential in a non-self-renewing progenitor compartment. Transcriptome analysis of GMPs revealed enrichment in gene signatures of self-renewal pathways, operating via direct Gli1 activation. Using human cell lines we demonstrated that in addition to canonical Hh signaling, GLI1 is activated in a Smoothened-independent manner. GLI1 knockdown or inhibition with GANT61 resulted in decreased proliferation and clonogenic potential. Our data suggest that GLI1 activation is frequent in MDS during disease progression and inhibition of GLI1 is an attractive therapeutic target for a subset of patients.

Hehlgans S, Booms P, Güllülü Ö, et al.
Radiation Sensitization of Basal Cell and Head and Neck Squamous Cell Carcinoma by the Hedgehog Pathway Inhibitor Vismodegib.
Int J Mol Sci. 2018; 19(9) [PubMed] Free Access to Full Article Related Publications
Vismodegib, an inhibitor of the Hedgehog signaling pathway, is an approved drug for monotherapy in locally advanced or metastatic basal cell carcinoma (BCC). Data on combined modality treatment by vismodegib and radiation therapy, however, are rare. In the present study, we examined the radiation sensitizing effects of vismodegib by analyzing viability, cell cycle distribution, cell death, DNA damage repair and clonogenic survival in three-dimensional cultures of a BCC and a head and neck squamous cell carcinoma (HNSCC) cell line. We found that vismodegib decreases expression of the Hedgehog target genes glioma-associated oncogene homologue (GLI1) and the inhibitor of apoptosis protein (IAP) Survivin in a cell line- and irradiation-dependent manner, most pronounced in squamous cell carcinoma (SCC) cells. Furthermore, vismodegib significantly reduced proliferation in both cell lines, while additional irradiation only slightly further impacted on viability. Analyses of cell cycle distribution and cell death induction indicated a G1 arrest in BCC and a G2 arrest in HNSCC cells and an increased fraction of cells in SubG1 phase following combined treatment. Moreover, a significant rise in the number of phosphorylated histone-2AX/p53-binding protein 1 (γH2AX/53BP1) foci in vismodegib- and radiation-treated cells was associated with a significant radiosensitization of both cell lines. In summary, these findings indicate that inhibition of the Hedgehog signaling pathway may increase cellular radiation response in BCC and HNSCC cells.

Jin S, He J, Li J, et al.
MiR-873 inhibition enhances gefitinib resistance in non-small cell lung cancer cells by targeting glioma-associated oncogene homolog 1.
Thorac Cancer. 2018; 9(10):1262-1270 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The five-year survival rate of non-small cell lung cancer (NSCLC) patients is very low. MiR-873 is involved in the growth, metastasis, and differentiation of tumors. Herein, we determined the target gene and influence of miR-873 in NSCLC.
METHODS: MiRanda and Targetscan websites were used to predict the target gene of miR-873 in NSCLC. Luciferase activity was examined using a dual luciferase reporter gene assay kit. The viability, tube formation, and proliferation of cells were analyzed by cell counting kit-8, angiogenic analysis, and flow cytometry, respectively. The levels of miR-873 and GLI1 were evaluated using quantitative real-time PCR and Western blot assays.
RESULTS: Low levels of GLI1 and high levels of miR-873 were observed in an NSCLC cell line (PC9) highly sensitive to EGFR-tyrosine kinase inhibitors. There was a negative correlation between miR-873 and GLI1 expression in PC9 and PC9/GR cells. The inhibition of miR-873 enhanced GLI1 levels. MiR-873 expression was inhibited by gefitinib. Gefitinib markedly reduced the viability, tube formation, and cell number in PC9 cells. However, suppression of miR-873 enhanced the resistance and knockdown of GLI1 enhanced the sensitivity of PC9 cells to gefitinib.
CONCLUSIONS: GLI1 is a target gene of miR-873 in NSCLC. The inhibition of miR-873 increased gefitinib resistance of NSCLC cells via the upregulation of GLI1. These results indicate that miR-873-GLI1 signaling is involved in gefitinib resistance in NSCLC.

Diao Y, Rahman MF, Vyatkin Y, et al.
Identification of novel GLI1 target genes and regulatory circuits in human cancer cells.
Mol Oncol. 2018; 12(10):1718-1734 [PubMed] Free Access to Full Article Related Publications
Hedgehog (HH) signaling is involved in many physiological processes, and pathway deregulation can result in a wide range of malignancies. Glioma-associated oncogene 1 (GLI1) is a transcription factor and a terminal effector of the HH cascade. Despite its crucial role in tumorigenesis, our understanding of the GLI1 cellular targets is quite limited. In this study, we identified multiple new GLI1 target genes using a combination of different genomic surveys and then subjected them to in-depth validation in human cancer cell lines. We were able to validate >90% of the new targets, which were enriched in functions involved in neurogenesis and regulation of transcription, in at least one type of follow-up experiment. Strikingly, we found that RNA editing of GLI1 can modulate effects on the targets. Furthermore, one of the top targets, FOXS1, a gene encoding a transcription factor previously implicated in nervous system development, was shown to act in a negative feedback loop limiting the cellular effects of GLI1 in medulloblastoma and rhabdomyosarcoma cells. Moreover, FOXS1 is both highly expressed and positively correlated with GLI1 in medulloblastoma samples of the Sonic HH subgroup, further arguing for the existence of FOXS1/GLI1 interplay in human tumors. Consistently, high FOXS1 expression predicts longer relapse-free survival in breast cancer. Overall, our findings open multiple new avenues in HH signaling pathway research and have potential for translational implications.

Hamaidi I, Coquard C, Danilin S, et al.
The Lim1 oncogene as a new therapeutic target for metastatic human renal cell carcinoma.
Oncogene. 2019; 38(1):60-72 [PubMed] Related Publications
Metastatic clear cell renal cell carcinoma (CCC) remains incurable despite advances in the development of anti-angiogenic targeted therapies and the emergence of immune checkpoint inhibitors. We have previously shown that the sonic hedgehog-Gli signaling pathway is oncogenic in CCC allowing us to identify the developmental Lim1 transcription factor as a Gli target and as a new oncogene in CCC regulating cell proliferation and apoptosis, and promoting tumor growth. In this previous study, preliminary in vitro results also suggested that Lim1 may be implicated in metastatic spread. Here we investigated the potential pro-metastatic role of Lim1 in advanced CCC (1) in vitro using a panel of CCC cell lines expressing or not the von Hippel-Lindau (VHL) tumor suppressor gene either naturally or by gene transfer and (2) ex vivo in 30 CCC metastatic tissues, including lymph nodes, lung, skin, bone, and adrenal metastases, and (3) in vivo, using a metastatic model by intravenous injection of siRNA-transfected cells into Balb/c nude. Our in vitro results reveal that Lim1 knockdown time-dependently decreased CCC cell motility, migration, invasion, and clonogenicity by up to 50% regardless of their VHL status. Investigating the molecular machinery involved in these processes, we identified a large panel of Lim1 targets known to be involved in cell adhesion (paxillin and fibronectin), epithelial-mesenchymal transition (Twist1/2 and snail), invasion (MMP1/2/3/8/9), and metastatic progression (CXCR4, SDF-1, and ANG-1). Importantly, Lim1 was found constitutively expressed in all metastatic tissues. The H-score in metastatic tissues being significantly superior to the score in the corresponding primary tumor tissues (P value = 0.009). Furthermore, we showed that Lim1 silencing decreases pulmonary metastasis development in terms of number and size in the in vivo metastatic model of human CCC. Taken together, these experiments strengthen the potential therapeutic value of Lim1 targeting as a promising novel approach for treating metastatic human CCC.

Liu X, Zhao T, Bai X, et al.
LOC101930370/MiR-1471 Axis Modulates the Hedgehog Signaling Pathway in Breast Cancer.
Cell Physiol Biochem. 2018; 48(3):1139-1150 [PubMed] Related Publications
BACKGROUND/AIMS: Non-coding RNAs (ncRNAs) play vital regulatory roles in many tumors. However, the functional roles of these transcripts responsible for their dysregulation in breast cancer (BC) are not thoroughly understood.
METHODS: We examined the expression of microRNA miR-1471 in BC specimens. Online analysis tools predicted that lncRNA LOC101930370 might act as an endogenous 'sponge' by competing for miR-1471 binding targets. Luciferase assays were used to prove the interaction of LOC101930370, miR-1471 and SHH. Edu, wound-healing and transwell assays were used to verify the contribution of miR-1471 and LOC101930370 on MCF-7 cells proliferation and metastasis. Gain and loss of function studies were performed to evaluate the relevance of Hedgehog pathway with LOC101930370/miR-1471 regulating axis in MCF-7 cells.
RESULTS: The expression of miR-1471 was markedly downregulated in BC. Inhibition of miR-1471 by LOC101930370 was proved by luciferase assay. Knockdown of LOC101930370 suppressed BC cells progression. MiR-1471 inhibitor resulted in a more aggressive metastasis of MCF-7 cells. Moreover, SHH and Gli-1 expression were significantly suppressed by LOC101930370 knockdown, and upregulated by miR-1471 inhibitor transfection.
CONCLUSIONS: Collectively, our study reveals the interaction between LOC101930370 and miR-1471 for the first time. LOC101930370 positively regulates the expression of SHH by sponging miR-1471, which sheds new light on lncRNA-directed diagnostics and therapeutics in BC.

Tanese K, Emoto K, Kubota N, et al.
Immunohistochemical visualization of the signature of activated Hedgehog signaling pathway in cutaneous epithelial tumors.
J Dermatol. 2018; 45(10):1181-1186 [PubMed] Related Publications
Activation of the Hedgehog (HH) signaling pathway plays a critical role in the development of basal cell carcinoma (BCC). HH signaling activity is produced by nuclear translocation of transcription factors, glioma-associated oncogene homolog (GLI). Among three GLI subfamilies, GLI1 is the only full-length transcriptional activator, and its nuclear localization is recognized as a signature event in HH signaling activation. However, limited published work has investigated the nuclear staining of GLI1 protein in human tumor tissue samples by immunohistochemical analysis. In this study, we performed immunohistochemical staining of GLI1 in 382 cases of cutaneous epithelial tumors, including 196 BCC cases, using rabbit monoclonal antihuman GLI1 antibody (C68H3). As a result, 98.2% cases of BCC showed a diffuse and strong nuclear staining pattern regardless of the histological subtype. Positive staining was mainly restricted to the tumor nests, while the overlying epidermis was negative suggesting specificity of the antibody. In further analysis of other cutaneous epithelial tumors, 100% (4/4) cases of trichoblastoma, 15.1% (5/33) Bowen's disease, 3.5% (1/28) actinic keratosis and 12.5% (4/32) squamous cell carcinoma showed the nuclear staining pattern of GLI1. This suggested that HH signaling is also dysregulated in some other cutaneous malignant tumors. In conclusion, the C68H3 antibody is a useful tool for revealing activation of HH signaling in immunohistochemical analysis.

Sternberg C, Gruber W, Eberl M, et al.
Synergistic cross-talk of hedgehog and interleukin-6 signaling drives growth of basal cell carcinoma.
Int J Cancer. 2018; 143(11):2943-2954 [PubMed] Free Access to Full Article Related Publications
Persistent activation of hedgehog (HH)/GLI signaling accounts for the development of basal cell carcinoma (BCC), a very frequent nonmelanoma skin cancer with rising incidence. Targeting HH/GLI signaling by approved pathway inhibitors can provide significant therapeutic benefit to BCC patients. However, limited response rates, development of drug resistance, and severe side effects of HH pathway inhibitors call for improved treatment strategies such as rational combination therapies simultaneously inhibiting HH/GLI and cooperative signals promoting the oncogenic activity of HH/GLI. In this study, we identified the interleukin-6 (IL6) pathway as a novel synergistic signal promoting oncogenic HH/GLI via STAT3 activation. Mechanistically, we provide evidence that signal integration of IL6 and HH/GLI occurs at the level of cis-regulatory sequences by co-binding of GLI and STAT3 to common HH-IL6 target gene promoters. Genetic inactivation of Il6 signaling in a mouse model of BCC significantly reduced in vivo tumor growth by interfering with HH/GLI-driven BCC proliferation. Our genetic and pharmacologic data suggest that combinatorial HH-IL6 pathway blockade is a promising approach to efficiently arrest cancer growth in BCC patients.

Ooki A, Dinalankara W, Marchionni L, et al.
Epigenetically regulated PAX6 drives cancer cells toward a stem-like state via GLI-SOX2 signaling axis in lung adenocarcinoma.
Oncogene. 2018; 37(45):5967-5981 [PubMed] Free Access to Full Article Related Publications
It remains unclear whether PAX6 acts as a crucial transcription factor for lung cancer stem cell (CSC) traits. We demonstrate that PAX6 acts as an oncogene responsible for induction of cancer stemness properties in lung adenocarcinoma (LUAD). Mechanistically, PAX6 promotes GLI transcription, resulting in SOX2 upregulation directly by the binding of GLI to the proximal promoter region of the SOX2 gene. The overexpressed SOX2 enhances the expression of key pluripotent factors (OCT4 and NANOG) and suppresses differentiation lineage factors (HOPX and NKX2-1), driving cancer cells toward a stem-like state. In contrast, in the differentiated non-CSCs, PAX6 is transcriptionally silenced by its promoter methylation. In human lung cancer tissues, the positive linear correlations of PAX6 expression with GLI and SOX2 expression and its negative correlations with HOPX and NKX2-1 expression were observed. Therapeutically, the blockade of the PAX6-GLI-SOX2 signaling axis elicits a long-lasting therapeutic efficacy by limiting CSC expansion following chemotherapy. Furthermore, a methylation panel including the PAX6 gene yielded a sensitivity of 79.1% and specificity of 83.3% for cancer detection using serum DNA from stage IA LUAD. Our findings provide a rationale for targeting the PAX6-GLI-SOX2 signaling axis with chemotherapy as an effective therapeutic strategy and support the clinical utility of PAX6 gene promoter methylation as a biomarker for early lung cancer detection.

Further References

Kinzler KW, Bigner SH, Bigner DD, et al.
Identification of an amplified, highly expressed gene in a human glioma.
Science. 1987; 236(4797):70-3 [PubMed] Related Publications
A gene, termed gli, was identified that is amplified more than 50-fold in a malignant glioma. The gene is expressed at high levels in the original tumor and its derived cell line and is located at chromosome 12 position (q13 to q14.3). The gli gene is a member of a select group of cellular genes that are genetically altered in primary human tumors.

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