Hedgehog inhibition with the orally bioavailable Smo antagonist LDE225 represses tumor growth and prolongs survival in a transgenic mouse model of islet cell neoplasms. Ann Surg. 2011;254:818-823; discussion 823. [PMID: 22042473 DOI: 10.1097/sla.0b013e318236bc0f]

Using drug scheduling to manage adverse events associated with hedgehog pathway inhibitors for basal cell carcinoma

Basal cell carcinoma (BCC) is the most common malignancy and form of skin cancer worldwide; advanced BCC, either as locally advanced BCC (laBCC) or metastatic BCC (mBCC), can cause substantial tissue invasion and morbidity. Until the recent availability of the hedgehog pathway inhibitors (HHIs) sonidegib and vismodegib, treatment options for advanced BCC were limited. These agents demonstrate efficacy in patients with laBCC and mBCC; however, the adverse events (AEs) associated with these agents can lead to treatment interruption or discontinuation and reduced quality of life, all of which significantly impact long-term adherence to therapy, which might affect clinical outcome. Given that most AEs are class-related effects, switching HHIs does not appear to lead to a significantly different AE profile, underscoring the importance of maintaining patients on their first HHI. Interrupting treatment of sonidegib and vismodegib does not appear to undermine the efficacy of these agents and is therefore a practical option to manage AEs in order to maintain continued treatment and disease control.

Analytical and bioanalytical HPLC method for simultaneous estimation of 5-fluorouracil and sonidegib

Aim: To develop a new sensitive RP-HPLC method for simultaneous estimation of 5-fluorouracil (5-FU) and sonidegib (SDG). Materials & methods: Analytical and bioanalytical methods for simultaneous quantification of 5-FU and SDG in bulk, nanoformulations and in rat plasma were developed and validated using a gradient elution technique. Results: Separation of the analytes was effected on a Luna^® C18 LC column using a mobile mixture comprising acetonitrile and acidified water. 5-FU and SDG were extracted from plasma matrix using liquid-liquid extraction. The applicability of the method was verified through single-dose oral pharmacokinetic study in Wistar rats. Conclusion: The developed methods allow a specific, sensitive and steady analytical procedure for the simultaneous estimation of 5-FU and SDG in nanoformulations and biological matrix.

Evaluation of Hedgehog Pathway Inhibitors as a Therapeutic Option for Uterine Leiomyosarcoma Using the Xenograft Model

Uterine leiomyosarcoma (LMS) contributes to a significant proportion of uterine cancer deaths. It is a rare and high-risk gynecological cancer. LMS is challenging to the treatment due to the resistance of several therapies. The activation of the Hedgehog (HH) pathway has been reported in several types of female cancers. Uterine LMS presents an upregulation of the crucial HH signaling pathway members such as SMO and GLI1. Although targeting the HH pathway exhibited a potent inhibitory effect on the phenotype of uterine LMS in vitro, the effect of the HH inhibitors on LMS growth in vivo has not been identified. The present study aimed to assess the effect of Hedgehog pathway inhibitors (SMO-LDE225 and GLI-Gant61) as a therapeutic option in the xenograft model of uterine LMS. The results demonstrated that LDE225 treatment did not show any inhibitory effect on LMS tumor growth; however, treatment with GLI inhibitor (Gant61) induced a remarkable tumor regression with a significant decrease in Ki67 expression, compared to control (p < 0.01). Moreover, administration of Gant61 decreased the expression of GLI1, GLI target genes BMP4 and c-MYC (p < 0.05), indicating that the HH pathway is implicated in the LMS experimental model. In conclusion, our studies demonstrate for the first time that GLI inhibitor (Gant61), but not SMO inhibitor (LDE225), shows a potent inhibitory effect on LMS tumor growth and concomitantly suppresses the expression of GLI1- and GLI-targeted genes using the xenograft model of uterine LMS.

Pancreatic Neuroendocrine Tumors: Molecular Mechanisms and Therapeutic Targets

Pancreatic neuroendocrine tumors (pNETs) are unique, slow-growing malignancies whose molecular pathogenesis is incompletely understood. With rising incidence of pNETs over the last four decades, larger and more comprehensive 'omic' analyses of patient tumors have led to a clearer picture of the pNET genomic landscape and transcriptional profiles for both primary and metastatic lesions. In pNET patients with advanced disease, those insights have guided the use of targeted therapies that inhibit activated mTOR and receptor tyrosine kinase (RTK) pathways or stimulate somatostatin receptor signaling. Such treatments have significantly benefited patients, but intrinsic or acquired drug resistance in the tumors remains a major problem that leaves few to no effective treatment options for advanced cases. This demands a better understanding of essential molecular and biological events underlying pNET growth, metastasis, and drug resistance. This review examines the known molecular alterations associated with pNET pathogenesis, identifying which changes may be drivers of the disease and, as such, relevant therapeutic targets. We also highlight areas that warrant further investigation at the biological level and discuss available model systems for pNET research. The paucity of pNET models has hampered research efforts over the years, although recently developed cell line, animal, patient-derived xenograft, and patient-derived organoid models have significantly expanded the available platforms for pNET investigations. Advancements in pNET research and understanding are expected to guide improved patient treatments.

The Role of the Hedgehog Pathway in Chemoresistance of Gastrointestinal Cancers

The hedgehog pathway, which plays a significant role in embryonic development and stem cell regulation, is activated in gastrointestinal cancers. Chemotherapy is widely used in cancer treatment. However, chemoresistance becomes a substantial obstacle in cancer therapy. This review focuses on the recent advances in the hedgehog pathway's roles in drug resistance of gastrointestinal cancers and the novel drugs and strategies targeting hedgehog signaling.

Studying the role of the immune system on the antitumor activity of a Hedgehog inhibitor against murine osteosarcoma

Recent evidence demonstrates that the efficacy of conventional anticancer therapies including chemotherapy requires a functional immune system. Here, we addressed the possibility that the antitumor effect of a selective Smoothened antagonist and Hedgehog (Hh) pathway inhibitor (LDE225), a promising anticancer drug, might at least partially depend on the immune system. To this aim, we used tumor cell lines derived from a murine model of radiation-induced osteosarcoma. In vitro treatment of osteosarcoma cells with LDE225 resulted in a decreased ability of tumor cells to proliferate, but had no effect on their viability. Flow cytometry analysis demonstrated that LDE225-treatment did not detectably modulate the immunogenicity of tumor cells. Moreover, LDE225 did not display any pro-apoptotic properties on osteosarcoma cells, highlighting that its antitumor profile mainly derives from a cytostatic effect. Furthermore, calreticulin exposure, a key feature of immunogenic cell death, was not provoked by LDE225, neither alone nor combined with recognized immunogenic drugs. Finally, the oral administration of LDE225 to osteosarcoma-bearing mice did significantly delay the tumor growth even in an immunocompromised setting. These data suggest that inhibiting Hh signaling can control osteosarcoma cell proliferation but does not modulate the immunogenic profile of these cells.

Safety and Tolerability of Sonic Hedgehog Pathway Inhibitors in Cancer

The hedgehog pathway, for which sonic hedgehog (Shh) is the most prominent ligand, is highly conserved and is tightly associated with embryonic development in a number of species. This pathway is also tightly associated with the development of several types of cancer, including basal cell carcinoma (BCC) and acute promyelocytic leukemia, among many others. Inactivating mutations in Patched-1 (PTCH1), leading to ligand-independent pathway activation, are frequent in several cancer types, but most prominent in BCC. This has led to the development of several compounds targeting this pathway as a cancer therapeutic. These compounds target the inducers of this pathway in Smoothened (SMO) and the GLI transcription factors, although targeting SMO has had the most success. Despite the many attempts at targeting this pathway, only three US FDA-approved drugs for cancers affect the Shh pathway. Two of these compounds, vismodegib and sonidegib, target SMO to suppress signaling from either PTCH1 or SMO mutations that lead to upregulation of the pathway. The other approved compound is arsenic trioxide, which can suppress this pathway at the level of the GLI proteins, although current evidence suggests it also has other targets. This review focuses on the safety and tolerability of these clinically approved drugs targeting the Shh pathway, along with a discussion on other Shh pathway inhibitors being developed.

Hedgehog signaling inhibitors in solid and hematological cancers

BACKGROUND

The hedgehog signaling pathway is normally tightly regulated. Mutations in hedgehog pathway components may lead to abnormal activation. Aberrantly activated hedgehog signaling plays a major role in the development of solid and hematological cancer. In recent years, inhibitors have been developed that attenuate hedgehog signaling; 2 have been approved for use in basal cell carcinoma (BCC), while others are under development or in clinical trials. The aim of this review is to provide an overview of known hedgehog inhibitors (HHIs) and their potential for the treatment of hematological cancers and solid tumors beyond BCC.

DESIGN

Published literature was searched to identify articles relating to HHIs in noncutaneous cancer. Both preclinical and clinical research articles were included. In addition, relevant clinical trial results were identified from www.clinicaltrials.gov. Information on the pharmacology of HHIs is also included.

RESULTS

HHIs show activity in a variety of solid and hematological cancers. In preclinical studies, HHIs demonstrated efficacy in pancreatic cancer, rhabdomyosarcoma, breast cancer, and acute myeloid leukemia (AML). In clinical studies, HHIs showed activity in medulloblastoma, as well as prostate, pancreatic, and hematological cancers. Current clinical trials testing the efficacy of HHIs are underway for prostate, pancreatic, and breast cancers, as well as multiple myeloma and AML.

CONCLUSIONS

As clinical trial results become available, it will be possible to discern which additional tumor types are suited to HHI mono- or combination therapy with other anticancer agents. The latter strategy may be useful for delaying or overcoming drug resistance.

Targeted therapy of gastroenteropancreatic neuroendocrine tumours: preclinical strategies and future targets

Molecular targeted therapy of advanced neuroendocrine tumours (NETs) of the gastroenteropancreatic (GEP) system currently encompasses approved therapy with the mammalian target of rapamycin (mTOR) inhibitor everolimus and the multi-tyrosinkinase inhibitor sunitinib. However, clinical efficacy of these treatment strategies is limited by low objective response rates and limited progression-free survival due to tumour resistance. Further novel strategies for molecular targeted therapy of NETs of the GEP system are needed. This paper reviews preclinical research models and signalling pathways in NETs of the GEP system. Preclinical and early clinical data on putative novel targets for molecular targeted therapy of NETs of the GEP system are discussed, including PI3K, Akt, mTORC1/mTORC2, GSK3, c-Met, Ras-Raf-MEK-ERK, embryogenic pathways (Hedgehog, Notch, Wnt/beta-catenin, TGF-beta signalling and SMAD proteins), tumour suppressors and cell cycle regulators (p53, cyclin-dependent kinases (CDKs) CDK4/6, CDK inhibitor p27, retinoblastoma protein (Rb)), heat shock protein HSP90, Aurora kinase, Src kinase family, focal adhesion kinase and epigenetic modulation by histone deacetylase inhibitors.

Exposure-Response Analysis of Sonidegib (LDE225), an Oral Inhibitor of the Hedgehog Signaling Pathway, for Effectiveness and Safety in Patients With Advanced Solid Tumors

Sonidegib selectively inhibits smoothened protein, suppresses the growth of Hedgehog pathway-dependent tumors, and has recently been approved in the indication of locally advanced basal cell carcinoma. A comprehensive exposure-response analysis was conducted to further characterize the relationship of sonidegib exposure to efficacy and safety. Minimum observed plasma concentration at predose (C_min ), peak concentration (C_max ), and area under the curve were used as exposure endpoints. Exposure-efficacy analyses included data from 190 patients who received sonidegib 200 mg or 800 mg once daily in the primary efficacy study. Objective response rate (ORR) (complete response [CR] or partial response [PR]), progression-free survival (PFS), and time to tumor response (TTR) were assessed by logistic regression, Cox regression, and Kaplan-Meier analyses. Exposure-safety (creatine phosphokinase [CK] elevation) analyses included data from 336 patients pooled from 4 clinical trials and included doses across ranges of 100 to 3000 mg once daily and 250 to 750 mg twice daily. Similar plasma exposure was observed between responders and nonresponders. The logistic regression model of week 5 C_min vs ORR indicated no relationship between sonidegib exposure resulting from 200 mg or 800 mg doses and the probability of CR or PR. A similar conclusion of no exposure-efficacy relationship was drawn from the PFS and TTR analyses. Increased exposure was associated with a greater risk of grade 3 or 4 CK elevation, with lower risk in females than in males when C_min was used in the model. These analyses support the sonidegib dose recommendation for registration and are consistent with clinical observations.

Hedgehog inhibitor sonidegib potentiates 177Lu-octreotate therapy of GOT1 human small intestine neuroendocrine tumors in nude mice

Background

¹⁷⁷Lu-octreotate can be used to treat somatostatin receptor expressing neuroendocrine tumors. It is highly effective in animal models, but clinical studies have so far only demonstrated low cure rates. Hedgehog inhibitors have shown therapeutic effect as monotherapy in neuroendocrine tumor model systems and might be one option to enhance the efficacy of ¹⁷⁷Lu-octreotate therapy. The aim of this study was to determine the therapeutic effect of combination therapy using ¹⁷⁷Lu-octreotate and the Hedgehog signaling pathway inhibitor sonidegib.

Methods

GOT1-bearing BALB/c nude mice were treated with either sonidegib (80 mg/kg twice a week via oral gavage), a single injection of 30 MBq ¹⁷⁷Lu-octreotate i.v., or a combination of both. Untreated animals served as controls. Tumor size was measured twice-weekly using calipers. The animals were killed 41 d after injection followed by excision of the tumors. Total RNA was extracted from each tumor sample and then subjected to gene expression analysis. Gene expression patterns were compared with those of untreated controls using Nexus Expression 3.0, IPA and Gene Ontology terms. Western blot was carried out on total protein extracted from the tumor samples to analyze activation-states of the Hh and PI3K/AKT/mTOR pathways.

Results

Sonidegib monotherapy resulted in inhibition of tumor growth, while a significant reduction in mean tumor volume was observed after ¹⁷⁷Lu-octreotate monotherapy and combination therapy. Time to progression was prolonged in the combination therapy group compared with ¹⁷⁷Lu-octreotate monotherapy. Gene expression analysis revealed a more pronounced response following combination therapy compared with both monotherapies, regarding the number of regulated genes and biological processes. Several cancer-related signaling pathways (i.e. Wnt/β-catenin, PI3K/AKT/mTOR, G-protein coupled receptor, and Notch) were affected by the combination therapy, but not by either monotherapy. Protein expression analysis revealed an activation of the Hh- and PI3K/AKT/mTOR pathways in tumors exposed to ¹⁷⁷Lu-octreotate monotherapy and combination therapy.

Conclusions

A comparative analysis of the different treatment groups showed that combination therapy using sonidegib and ¹⁷⁷Lu-octreotate could be beneficial to patients with neuroendocrine tumors. Gene expression analysis revealed a functional interaction between sonidegib and ¹⁷⁷Lu-octreotate, i.e. several cancer-related signaling pathways were modulated that were not affected by either monotherapy. Protein expression analysis indicated a possible PI3K/AKT/mTOR-dependent activation of the Hh pathway, independent of SMO.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3524-x) contains supplementary material, which is available to authorized users.

Hedgehog signaling pathway affects the sensitivity of hepatoma cells to drug therapy through the ABCC1 transporter

The poor response to drug therapy often seen in hepatocellular carcinoma requires insight into the molecular interplay responsible for intrinsic or acquired drug resistance. We previously demonstrated that the CD133^-/EpCAM^- subpopulation of the Huh-7 hepatoma cell line features aberrant activation of the hedgehog signaling (Hh) pathway and chemoresistance. The prevailing hypothesis of the present study is that hedgehog signaling may govern expression of ATP-binding cassette (ABC) transporters, which are responsible for drug resistance in the CD133^-/EpCAM^- subpopulation. Our aim is to reveal the molecular interplay in the mediation of drug resistance with a newly established Huh-7 subpopulation featuring high Hh signaling activity and drug resistance. In this study, chemoresistance was determined in a newly established Huh-7-DN subpopulation featuring the CD133^-/EpCAM^- surface marker profile, aberrant expression of Hh pathway, and epithelial-mesenchymal transition (EMT). Expression of ABC transporter proteins (ABCB1, ABCC1, and ABCG2) and Hh transcription factor Gli-1/2 was evaluated with and without Hh signaling antagonists LDE225 or itraconazole. We found that hedgehog signaling activity as determined by transfection with a Gli-Lux reporter cassette and gene expression levels tended to increase from Huh-7 CD133⁺/EpCAM⁺ to CD133^-/EpCAM^-, and the highest levels were found in Huh-7-DN cells. The Huh-7-DN subpopulation exhibited characteristics of EMT as evidenced by increased expression of vimentin and loss of E-cadherin. Sorafenib significantly inhibited the viability of all subpopulations except the Huh-7-DN subpopulation. Compared with other sorafenib-sensitive subpopulations, the Huh-7-DN subpopulation showed enhanced expression of Hh transcription factor Gli-2 and ABCC1 transporter protein. Silencing Gli-2 by lentivirus harboring shRNA against Gli-2 or LDE225 significantly suppressed expression of Gli-2 and ABCC1 genes in Huh-7-DN subpopulation. In conclusion, aberrant hedgehog signaling activation is linked to poor differentiation, epithelial-mesenchymal transition, and chemoresistance in the Huh-7-DN subpopulation. Hedgehog signaling transcription factor Gli-2 appears to be the primary regulator for drug sensitivity of hepatoma through the ABCC1 transporter.

Sonidegib: First Global Approval

Sonidegib (Odomzo™) is an orally bioavailable, small molecule, Smoothened (SMO) receptor antagonist that is being developed by Novartis for the treatment of cancer. SMO is a G protein-coupled receptor-like molecule that is essential for the actions of the Hedgehog family of secreted proteins, which play a critical role in the development and homeostasis of many organs and tissues. Oral sonidegib is approved in Switzerland for the treatment of adult patients with advanced basal cell carcinoma (BCC) and in the US and EU for the treatment of adult patients with locally advanced BCC that has recurred following surgery or radiation therapy, or those who are not candidates for surgery or radiation therapy. Submissions to other global authorities are being contemplated or planned. Additionally, phase I/II investigation is being conducted in other malignancies, including multiple myeloma, medulloblastoma, myelofibrosis, ovarian cancer, prostate cancer, breast cancer, chronic myeloid leukaemia, myelodysplastic syndromes, oesophageal cancer and pancreatic cancer. This article summarizes the milestones in the development of sonidegib leading to the first approvals for advanced and locally advanced BCC.

A genome scale RNAi screen identifies GLI1 as a novel gene regulating vorinostat sensitivity

Vorinostat is an FDA-approved histone deacetylase inhibitor (HDACi) that has proven clinical success in some patients; however, it remains unclear why certain patients remain unresponsive to this agent and other HDACis. Constitutive STAT (signal transducer and activator of transcription) activation, overexpression of prosurvival Bcl-2 proteins and loss of HR23B have been identified as potential biomarkers of HDACi resistance; however, none have yet been used to aid the clinical utility of HDACi. Herein, we aimed to further elucidate vorinostat-resistance mechanisms through a functional genomics screen to identify novel genes that when knocked down by RNA interference (RNAi) sensitized cells to vorinostat-induced apoptosis. A synthetic lethal functional screen using a whole-genome protein-coding RNAi library was used to identify genes that when knocked down cooperated with vorinostat to induce tumor cell apoptosis in otherwise resistant cells. Through iterative screening, we identified 10 vorinostat-resistance candidate genes that sensitized specifically to vorinostat. One of these vorinostat-resistance genes was GLI1, an oncogene not previously known to regulate the activity of HDACi. Treatment of vorinostat-resistant cells with the GLI1 small-molecule inhibitor, GANT61, phenocopied the effect of GLI1 knockdown. The mechanism by which GLI1 loss of function sensitized tumor cells to vorinostat-induced apoptosis is at least in part through interactions with vorinostat to alter gene expression in a manner that favored apoptosis. Upon GLI1 knockdown and vorinostat treatment, BCL2L1 expression was repressed and overexpression of BCL2L1 inhibited GLI1-knockdown-mediated vorinostat sensitization. Taken together, we present the identification and characterization of GLI1 as a new HDACi resistance gene, providing a strong rationale for development of GLI1 inhibitors for clinical use in combination with HDACi therapy.

PDGFRα up-regulation mediated by sonic hedgehog pathway activation leads to BRAF inhibitor resistance in melanoma cells with BRAF mutation

Control of BRAF(V600E) metastatic melanoma by BRAF inhibitor (BRAF-I) is limited by intrinsic and acquired resistance. Growth factor receptor up-regulation is among the mechanisms underlying BRAF-I resistance of melanoma cells. Here we demonstrate for the first time that PDGFRα up-regulation causes BRAF-I resistance. PDGFRα inhibition by PDGFRα-specific short hairpin (sh)RNA and by PDGFRα inhibitors restores and increases melanoma cells' sensitivity to BRAF-I in vitro and in vivo. This effect reflects the inhibition of ERK and AKT activation which is associated with BRAF-I resistance of melanoma cells. PDGFRα up-regulation is mediated by Sonic Hedgehog Homolog (Shh) pathway activation which is induced by BRAF-I treatment. Similarly to PDGFRα inhibition, Shh inhibition by LDE225 restores and increases melanoma cells' sensitivity to BRAF-I. These effects are mediated by PDGFRα down-regulation and by ERK and AKT inhibition. The clinical relevance of these data is indicated by the association of PDGFRα up-regulation in melanoma matched biopsies of BRAF-I +/- MEK inhibitor treated patients with shorter time to disease progression and less tumor regression. These findings suggest that monitoring patients for early PDGFRα up-regulation will facilitate the identification of those who may benefit from the treatment with BRAF-I in combination with clinically approved PDGFRα or Shh inhibitors.

Enalapril and ASS inhibit tumor growth in a transgenic mouse model of islet cell tumors

Accumulating evidence suggests a role for angiotensin-converting enzymes involving the angiotensin II-receptor 1 (AT1-R) and the cyclooxygenase pathway in carcinogenesis. The effects of ASS and enalapril were assessed in vitro and in a transgenic mouse model of pancreatic neuroendocrine neoplasms (pNENs). The effects of enalapril and ASS on proliferation and expression of the AGTR1A and its target gene vascular endothelial growth factor (Vegfa) were assessed in the neuroendocrine cell line BON1. Rip1-Tag2 mice were treated daily with either 0.6 mg/kg bodyweight of enalapril i.p., 20 mg/kg bodyweight of ASS i.p., or a vehicle in a prevention (weeks 5-12) and a survival group (week 5 till death). Tumor surface, weight of pancreatic glands, immunostaining for AT1-R and nuclear factor kappa beta (NFKB), and mice survival were analyzed. In addition, sections from human specimens of 20 insulinomas, ten gastrinomas, and 12 non-functional pNENs were evaluated for AT1-R and NFKB (NFKB1) expression and grouped according to the current WHO classification. Proliferation was significantly inhibited by enalapril and ASS in BON1 cells, with the combination being the most effective. Treatment with enalapril and ASS led to significant downregulation of known target genes Vegf and Rela at RNA level. Tumor growth was significantly inhibited by enalapril and ASS in the prevention group displayed by a reduction of tumor size (84%/67%) and number (30%/45%). Furthermore, daily treatment with enalapril and ASS prolonged the overall median survival compared with vehicle-treated Rip1-Tag2 (107 days) mice by 9 and 17 days (P=0.016 and P=0.013). The AT1-R and the inflammatory transcription factor NFKB were abolished completely upon enalapril and ASS treatment. AT1-R and NFKB expressions were observed in 80% of human pNENs. Enalapril and ASS may provide an approach for chemoprevention and treatment of pNENs.

Inhibition of Hedgehog signalling by NVP-LDE225 (Erismodegib) interferes with growth and invasion of human renal cell carcinoma cells

Background:

Multiple lines of evidence support that the Hedgehog (Hh) signalling has a role in the maintenance and progression of different human cancers. Therefore, inhibition of the Hh pathway represents a valid anticancer therapeutic approach for renal cell carcinoma (RCC) patients. NVP-LDE225 is a Smoothened (Smo) antagonist that induces dose-related inhibition of Hh and Smo-dependent tumour growth.

Methods:

We assayed the effects of NVP-LDE225 alone or in combination with everolimus or sunitinib on the growth and invasion of human RCC models both in vitro and in vivo. To this aim, we used a panel of human RCC models, comprising cells with acquired resistance to sunitinib – a multiple tyrosine kinase inhibitor approved as a first-line treatment for RCC.

Results:

NVP-LDE225 cooperated with either everolimus or sunitinib to inhibit proliferation, migration, and invasion of RCC cells even in sunitinib-resistant (SuR) cells. Some major transducers involved in tumour cell motility, including paxillin, were also efficiently inhibited by the combination therapy, as demonstrated by western blot and confocal microscopy assays. Moreover, these combined treatments inhibited tumour growth and increased animal survival in nude mice xenografted with SuR RCC cells. Finally, lung micrometastasis formation was reduced when mice were treated with NVP-LDE225 plus everolimus or sunitinib, as evidenced by artificial metastatic assays.

Conclusions:

Hedgehog inhibition by NVP-LDE225 plus sunitinib or everolimus bolsters antitumour activity by interfering with tumour growth and metastatic spread, even in SuR cells. Thus, this new evidence puts forward a new promising therapeutic approach for RCC patients.

Chronic pancreatitis and systemic inflammatory response syndrome prevent impact of chemotherapy with gemcitabine in a genetically engineered mouse model of pancreatic cancer

BACKGROUND AND AIMS

BACKGROUND AND AIMSGemcitabine is the standard therapy for patients with pancreatic cancer with metastatic disease. Patients with metastatic pancreatic cancer presenting with increased values of C-reactive protein do not respond to gemcitabine. So far, no studies have evaluated the correlation between chronic pancreatitis, systemic inflammatory response syndrome, and the loss of chemotherapeutic benefit.

METHODS

Pdx-1-Cre;LSL-Kras(G12D/+);LSL-Trp53(R172H/+) mice were assigned into four groups: 1) Sixteen animals received a daily intraperitoneal injection of caerulein from their ninth week of life on. 2) Sixteen mice were additionally given gemcitabine. 3) Twelve animals received gemcitabine only. 4) Saline-treated control group. Furthermore, human Paca44 pancreatic ductal adenocarcinoma cells were seeded and cultured in 0.5% FBS containing growth medium plus/minus 1 μM gemcitabine plus/minus recombinant human interleukin (IL)-6.

RESULTS

Induced systemic inflammatory response syndrome and a mild chronic pancreatitis diminished the beneficial effects of gemcitabine upon median overall survival. In median, the monogemcitabine group survived 191 days, whereas the caerulein-mono group survived 114, the control group 121, and the caerulein gemcitabine group 127 days (P < .05). In vitro, the induction of STAT3 phosphorylation by recombinant human IL-6 promoted pancreatic ductal adenocarcinoma cell survival during gemcitabine treatment.

CONCLUSION

We could demonstrate for the first time that an improvement in median overall survival with gemcitabine is significantly abolished by a persistent mild chronic pancreatitis and a systemic inflammatory response syndrome. In particular, the inflammation biomarkers C-reactive protein, IL-6, and IL-1α could indicate the prognostic benefit of gemcitabine chemotherapy and should now be tested in prospective patient-controlled trials.

Hedgehog signaling pathway as a new therapeutic target in pancreatic cancer

Pancreatic cancer is one of the most aggressive and difficult cancers to treat. Despite numerous research efforts, limited success has been achieved in the therapeutic management of patients with this disease. In the current review, we focus on one component of morphogenesis signaling, Hedgehog (Hh), with the aim of developing novel, effective therapies for the treatment of pancreatic cancer. Hh signaling contributes to the induction of a malignant phenotype in pancreatic cancer and is responsible for maintaining pancreatic cancer stem cells. In addition, we propose a novel concept linking Hh signaling and tumor hypoxic conditions, and discuss the effects of Hh inhibitors in clinical trials. The Hh signaling pathway may represent a potential therapeutic target for patients with refractory pancreatic cancer.

CUX1: a modulator of tumour aggressiveness in pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (PNENs) constitute a rare tumour entity, and prognosis and treatment options depend on tumour-mediating hallmarks such as angiogenesis, proliferation rate and resistance to apoptosis. The molecular pathways that determine the malignant phenotype are still insufficiently understood and this has limited the use of effective combination therapies in the past. In this study, we aimed to characterise the effect of the oncogenic transcription factor Cut homeobox 1 (CUX1) on proliferation, resistance to apoptosis and angiogenesis in murine and human PNENs. The expression and function of CUX1 were analysed using knockdown and overexpression strategies in Ins-1 and Bon-1 cells, xenograft models and a genetically engineered mouse model of insulinoma (RIP1Tag2). Regulation of angiogenesis was assessed using RNA profiling and functional tube-formation assays in HMEC-1 cells. Finally, CUX1 expression was assessed in a tissue microarray of 59 human insulinomas and correlated with clinicopathological data. CUX1 expression was upregulated during tumour progression in a time- and stage-dependent manner in the RIP1Tag2 model, and associated with pro-invasive and metastatic features of human insulinomas. Endogenous and recombinant CUX1 expression increased tumour cell proliferation, tumour growth, resistance to apoptosis, and angiogenesis in vitro and in vivo. Mechanistically, the pro-angiogenic effect of CUX1 was mediated via upregulation of effectors such as HIF1α and MMP9. CUX1 mediates an invasive pro-angiogenic phenotype and is associated with malignant behaviour in human insulinomas.

An Efficient Synthesis of Erismodegib

A highly efficient synthesis of Erismodegib (LDE225) is described. The chlorine of 2-chloro-5-nitropyridine was displaced by 2,6-dimethylmorpholine and the nitro group reduced to give 3-amino-6-(2’,6'-dimethylmorpholino)pyridine. The Suzuki coupling of methyl 3-bromo-2-methylbenzoate with 4-trifluoromethoxy phenylboronic acid gave methyl-4'-(trifluormethoxy) biphenyl-3-carboxylate. These two fragments were coupled through amide bond formation to give Erismodegib. This synthesis procedure which proceeded in high yield did not require special conditions and is suitable for industrial production.

Menin epigenetically represses Hedgehog signaling in MEN1 tumor syndrome

Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumor syndrome that includes susceptibility to pancreatic islet tumors. This syndrome results from mutations in the MEN1 gene, encoding menin. Although menin acts as an oncogenic cofactor for mixed lineage leukemia (MLL) fusion protein-mediated histone H3 lysine 4 methylation, the precise basis for how menin suppresses gene expression and proliferation of pancreatic beta cells remains poorly understood. Here, we show that menin ablation enhances Hedgehog signaling, a proproliferative and oncogenic pathway, in murine pancreatic islets. Menin directly interacts with protein arginine methyltransferase 5 (PRMT5), a negative regulator of gene transcription. Menin recruits PRMT5 to the promoter of the Gas1 gene, a crucial factor for binding of Sonic Hedgehog (Shh) ligand to its receptor PTCH1 and subsequent activation of the Hedgehog signaling pathway, increases repressive histone arginine symmetric dimethylation (H4R3m2s), and suppresses Gas1 expression. Notably, MEN1 disease-related menin mutants have reduced binding to PRMT5, and fail to impart the repressive H4R3m2s mark at the Gas1 promoter, resulting in its elevated expression. Pharmacologic inhibition of Hedgehog signaling significantly reduces proliferation of insulinoma cells, and expression of Hedgehog signaling targets including Ptch1, in MEN1 tumors of mice. These findings uncover a novel link between menin and Hedgehog signaling whereby menin/PRMT5 epigenetically suppresses Hedgehog signaling, revealing it as a target for treating MEN1 tumors.

Sorafenib inhibits tumor growth and improves survival in a transgenic mouse model of pancreatic islet cell tumors

BACKGROUND

The purpose of the study was to evaluate Sorafenib (BAY 43-9006) derived receptor tyrosine kinase inhibition on tumor progression in murine islet cell tumors. Sorafenib is considered to be a potent inhibitor of tumor angiogenesis and neovascularization in various solid tumors. Rip1Tag2 mice were treated in two different groups according to the model of tumor progression: the early treatment group received vehicle or Sorafenib from 10 to 14 weeks of age and the late treatment group from week 12 until death. Tumor surface, tumor cell proliferation, and apoptosis were measured in both treatment groups to assess the in vivo effects of Sorafenib. Survival was recorded for the late treatment group. In the early treatment group Sorafenib led to a dramatic decrease in tumor volume compared to the control group. Apoptosis was significantly augmented and cell proliferation was inhibited. As a single therapy Sorafenib significantly improved survival in the late treatment group. Conclusion. Sorafenib may provide a new paradigm for the therapy of islet cell tumors.

Novel molecular targets for the treatment of gastroenteropancreatic endocrine tumors: answers and unsolved problems

As more knowledge on molecular alterations favoring carcinogenesis and spreading of gastroenteropancreatic endocrine tumors has become available, a number of targeted agents interfering with key growth and angiogenic pathways have been explored in preclinical and clinical studies. The mTOR inhibitor Everolimus, and the multi-target antiangiogenetic agent Sunitinib, have been shown to be effective and thus have been approved by the FDA for treatment of pancreatic endocrine tumors. However, there is little data on the primary resistance to targeted agents on these tumors. The goals of the present review are to elucidate the possible advantage of combined treatments in overcoming induced resistances, and to identify biomarkers able to predict clinical efficacy. Moreover, the role of interesting targets for which a strong biological rationale exists, and specific inhibitors are available, such as the Src Family Kinases and the Hedgehog Pathway, are discussed. There is now need for more preclinical studies on cell lines and animal models to provide a stronger preclinical background in this field, as well as clinical trials specifically comparing one targeted therapy with another or combining different targeted agents.

Medical treatment of gastroenteropancreatic neuroendocrine tumors

Treatment of the clinically and prognostically heterogeneous neuroendocrine neoplasms (NEN) should be based on a multidisciplinary approach, including surgical, interventional, medical and nuclear medicine-based therapeutic options. Medical therapies include somatostatin analogues, interferon-α, mTOR inhibitors, multikinase inhibitors and systemic chemotherapy. For the selection of the appropriate medical treatment the hormonal activity, primary tumor localization, tumor grading and growth behaviour as well as the extent of the disease must be considered. Somatostatin analogues are mainly indicated in hormonally active tumors for symptomatic relief, but antiproliferative effects have also been demonstrated, especially in well-differentiated intestinal NET. The efficacy of everolimus and sunitinib in patients with pancreatic neuroendocrine tumors (pNET) has been demonstrated in large placebo-controlled clinical trials. pNETs are also chemosensitive. Streptozocin-based chemotherapeutic regimens are regarded as current standard of care. Temozolomide in combination with capecitabine is an alternative that has shown promising results that need to be confirmed in larger trials. Currently, no comparative studies and no molecular markers are established that predict the response to medical treatment. Therefore the choice of treatment for each pNET patient is based on individual parameters taking into account the patient’s preference, expected side effects and established response criteria such as proliferation rate and tumor load. Platin-based chemotherapy is still the standard treatment for poorly differentiated neuroendocrine carcinomas. Clearly, there is an unmet need for new systemic treatment options in patients with extrapancreatic neuroendocrine tumors.