Further pharmacological and genetic evidence for the efficacy of PlGF inhibition in cancer and eye disease.

Our findings that PlGF is a cancer target and anti-PlGF is useful for anticancer treatment have been challenged by Bais et al. Here we take advantage of carcinogen-induced and transgenic tumor models as well as ocular neovascularization to report further evidence in support of our original findings of PlGF as a promising target for anticancer therapies. We present evidence for the efficacy of additional anti-PlGF antibodies and their ability to phenocopy genetic deficiency or silencing of PlGF in cancer and ocular disease but also show that not all anti-PlGF antibodies are effective. We also provide additional evidence for the specificity of our anti-PlGF antibody and experiments to suggest that anti-PlGF treatment will not be effective for all tumors and why. Further, we show that PlGF blockage inhibits vessel abnormalization rather than density in certain tumors while enhancing VEGF-targeted inhibition in ocular disease. Our findings warrant further testing of anti-PlGF therapies.

Periostin- and podoplanin-positive cancer-associated fibroblast subtypes cooperate to shape the inflamed tumor microenvironment in aggressive pancreatic adenocarcinoma.

Cancer-associated fibroblasts (CAFs) are orchestrators of the pancreatic ductal adenocarcinoma (PDAC) microenvironment. Previously we described four CAF subtypes with specific molecular and functional features. Here, we have refined our CAF subtype signatures using RNAseq and immunostaining with the goal of defining bioinformatically the phenotypic stromal and tumor epithelial states associated with CAF diversity. We used primary CAF cultures grown from patient PDAC tumors, human data sets (in-house and public, including single-cell analyses), genetically engineered mouse PDAC tissues, and patient-derived xenografts (PDX) grown in mice. We found that CAF subtype RNAseq signatures correlated with immunostaining. Tumors rich in periostin-positive CAFs were significantly associated with shorter overall survival of patients. Periostin-positive CAFs were characterized by high proliferation and protein synthesis rates and low α-smooth muscle actin expression and were found in peri-/pre-tumoral areas. They were associated with highly cellular tumors and with macrophage infiltrates. Podoplanin-positive CAFs were associated with immune-related signatures and recruitment of dendritic cells. Importantly, we showed that the combination of periostin-positive CAFs and podoplanin-positive CAFs was associated with specific tumor microenvironment features in terms of stromal abundance and immune cell infiltrates. Podoplanin-positive CAFs identified an inflammatory CAF (iCAF)-like subset, whereas periostin-positive CAFs were not correlated with the published myofibroblastic CAF (myCAF)/iCAF classification. Taken together, these results suggest that a periostin-positive CAF is an early, activated CAF, associated with aggressive tumors, whereas a podoplanin-positive CAF is associated with an immune-related phenotype. These two subpopulations cooperate to define specific tumor microenvironment and patient prognosis and are of putative interest for future therapeutic stratification of patients. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Inter- and intra-tumoural heterogeneity in cancer-associated fibroblasts of human pancreatic ductal adenocarcinoma.

Cancer-associated fibroblasts (CAF) are orchestrators of the pancreatic ductal adenocarcinoma (PDAC) microenvironment. Stromal heterogeneity may explain differential pathophysiological roles of the stroma (pro- versus anti-tumoural) in PDAC. We hypothesised that multiple CAF functional subtypes exist in PDAC, that contribute to stromal heterogeneity through interactions with cancer cells. Using molecular and functional analysis of patient-derived CAF primary cultures, we demonstrated that human PDAC-derived CAFs display a high level of inter- and intra-tumour heterogeneity. We identified at least four subtypes of CAFs based on transcriptomic analysis, and propose a classification for human PDAC-derived CAFs (pCAFassigner). Multiple CAF subtypes co-existed in individual patient samples. The presence of these CAF subtypes in bulk tumours was confirmed using publicly available gene expression profiles, and immunostainings of CAF subtype markers. Each subtype displayed specific phenotypic features (matrix- and immune-related signatures, vimentin and α-smooth muscle actin expression, proliferation rate), and was associated with an assessable prognostic impact. A prolonged exposure of non-tumoural pancreatic stellate cells to conditioned media from cancer cell lines (cancer education experiment) induced a CAF-like phenotype, including loss of capacity to revert to quiescence and an increase in the expression of genes related to CAF subtypes B and C. This classification demonstrates molecular and functional inter- and intra-tumoural heterogeneity of CAFs in human PDAC. Our subtypes overlap with those identified from single-cell analyses in other cancers, and pave the way for the development of therapies targeting specific CAF subpopulations in PDAC. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

High c-Met expression in stage I-II pancreatic adenocarcinoma: proposal for an immunostaining scoring method and correlation with poor prognosis.

AIMS: c-Met is an emerging biomarker in pancreatic ductal adenocarcinoma (PDAC); there is no consensus regarding the immunostaining scoring method for this marker. We aimed to assess the prognostic value of c-Met overexpression in resected PDAC, and to elaborate a robust and reproducible scoring method for c-Met immunostaining in this setting. METHODS AND RESULTS: c-Met immunostaining was graded according to the validated MetMab score, a classic visual scale combining surface and intensity (SI score), or a simplified score (high c-Met: ≥ 20% of tumour cells with strong membranous staining), in stage I-II PDAC. A computer-assisted classification method (Aperio software) was developed. Clinicopathological parameters were correlated with disease-free survival (DFS) and overall survival(OS). One hundred and forty-nine patients were analysed retrospectively in a two-step process. Thirty-seven samples (whole slides) were analysed as a pre-run test. Reproducibility values were optimal with the simplified score (kappa = 0.773); high c-Met expression (7/37) was associated with shorter DFS [hazard ratio (HR) 3.456, P = 0.0036] and OS (HR 4.257, P = 0.0004). c-Met expression was concordant on whole slides and tissue microarrays in 87.9% of samples, and quantifiable with a specific computer-assisted algorithm. In the whole cohort (n = 131), patients with c-Met(high) tumours (36/131) had significantly shorter DFS (9.3 versus 20.0 months, HR 2.165, P = 0.0005) and OS (18.2 versus 35.0 months, HR 1.832, P = 0.0098) in univariate and multivariate analysis. CONCLUSIONS: Simplified c-Met expression is an independent prognostic marker in stage I-II PDAC that may help to identify patients with a high risk of tumour relapse and poor survival.

Targeting the Ras-ERK pathway in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PAC) stands as the poorest prognostic tumor of the digestive tract with limited therapeutic options. PAC carcinogenesis is associated with the loss of function of tumor suppressor genes such as INK4A, TP53, BRCA2, and DPC4, and only a few activated oncogenes among which K-RAS mutations are the most prevalent. The K-RAS mutation occurs early in PAC carcinogenesis, driving downstream activation of MEK and ERK1/2 which promote survival, invasion, and migration of cancer cells. In PAC models, inhibition of members of the Ras-ERK pathway blocks cellular proliferation and metastasis development. As oncogenic Ras does not appear to be a suitable drug target, inhibitors targeting downstream kinases including Raf and MEK have been developed and are currently under evaluation in clinical trials. In this review, we describe the role of the Ras-ERK pathway in pancreatic carcinogenesis and as a new therapeutic target for the treatment of PAC.

Stromal expression of SPARC in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) stands as the poorest prognostic tumor of the digestive tract, with a 5-year survival rate of less than 5%. Therapeutic options for unresectable PDAC are extremely limited and there is a pressing need for expanded therapeutic approaches to improve current options available with gemcitabine-based regimens. With PDAC displaying one of the most prominent desmoplastic stromal reactions of all carcinomas, recent research has focused on the microenvironment surrounding PDAC cells. Secreted protein acid and rich in cysteine (SPARC), which is overexpressed in PDAC, may display tumor suppressor functions in several cancers (e.g., in colorectal, ovarian, prostate cancers, and acute myelogenous leukemia) but also appears to be overexpressed in other tumor types (e.g., breast cancer, melanoma, and glioblastoma). The apparent contradictory functions of SPARC may yield inhibition of angiogenesis via inhibition of vascular endothelial growth factor, while promoting epithelial-to-mesenchymal transition and invasion through matrix metalloprotease expression. This feature is of particular interest in PDAC where SPARC overexpression in the stroma stands along with inhibition of angiogenesis and promotion of cancer cell invasion and metastasis. Several therapeutic strategies to deplete stromal tissue have been developed. In this review, we focused on key preclinical and clinical data describing the role of SPARC in PDAC biology, the properties, and mechanisms of delivery of drugs that interact with SPARC and discuss the proof-of-concept clinical trials using nab-paclitaxel.

Ezurpimtrostat, A Palmitoyl-Protein Thioesterase-1 Inhibitor, Combined with PD-1 Inhibition Provides CD8+ Lymphocyte Repopulation in Hepatocellular Carcinoma.

BACKGROUND: Palmitoyl-protein thioesterase-1 (PPT1) is a clinical stage druggable target for inhibiting autophagy in cancer. OBJECTIVE: We aimed to determine the cellular and molecular activity of targeting PPT1 using ezurpimtrostat, in combination with an anti-PD-1 antibody. METHODS: In this study we used a transgenic immunocompetent mouse model of hepatocellular carcinoma. RESULTS: Herein, we revealed that inhibition of PPT1 using ezurpimtrostat decreased the liver tumor burden in a mouse model of hepatocellular carcinoma by inducing the penetration of lymphocytes into tumors when combined with anti-programmed death-1 (PD-1). Inhibition of PPT1 potentiates the effects of anti-PD-1 immunotherapy by increasing the expression of major histocompatibility complex (MHC)-I at the surface of liver cancer cells and modulates immunity through recolonization and activation of cytotoxic CD8+ lymphocytes. CONCLUSIONS: Ezurpimtrostat turns cold tumors into hot tumors and, thus, could improve T cell-mediated immunotherapies in liver cancer.

Pancreatic cancer orthotopic graft in a murine model.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with increasing incidence. Even if progress have been made, the five-year overall survival remains lower than 10%. There is a desperate need in therapeutic improvements. In the last two decades, new in-vitro models have been developed and improved, including tridimensional-culture spheroids and organoids. However, animal studies remain mandatory in the upscaling before clinical studies. Orthotopic and syngeneic grafting is a robust model to test a drug efficiency in a tumor and its microenvironment. METHODS: We described a method for orthotopic and syngeneic graft of KRAS mutated, p53 wildtype, 8305 cells in a C57BL/6J mouse model. RESULTS: With this microsurgical method, 30 mice were grafted, 24 by a junior and six by a senior, resulting in 95,8 and 100% of (partial and total) successful tumoral implantation, respectively. Twenty mice underwent ultrasound follow-up. It was an efficient method for the tumoral growth evaluation. At day 16 after grafting, 85% of the tumors were detectable by ultrasound, and at day 22 all tumors were detected. CONCLUSIONS: The presented method appears to be a robust and reliable method for pre-clinical studies. A junior master student can provide positive results using this technique, which can be improved with training.

Netrin-4 delays colorectal cancer carcinomatosis by inhibiting tumor angiogenesis.

A close relationship between tumor angiogenesis, growth, and carcinomatosis has been observed. Netrin-4 (NT-4) has been shown to regulate angiogenic responses. We aimed to examine the effects of NT-4 on colon tumor angiogenesis, growth, and carcinomatosis. We showed that NT-4 was expressed in human colon cancer cells (LS174). A 20-fold increase in NT-4 expression was stably induced by NT-4 pcDNA in LS174 cells. In vivo, a Matrigel angiogenesis assay showed that NT-4 overexpression altered vascular endothelial growth factor (VEGF)/basic fibroblast growth factor-induced angiogenesis. In nude mice with LS174 xenografts, NT-4 overexpression inhibited tumor angiogenesis and growth. In addition, these NT-4-involved inhibitory effects were associated with decreased tumor cell proliferation and increased tumor cell apoptosis. Using an orthotopic peritoneal carcinomatosis model, we demonstrated that NT-4 overexpression decreased colorectal cancer carcinomatosis. Moreover, carcinomatosis-related ascites formation was significantly decreased in mice transplanted with NT-4 LS174 cells versus control LS174 cells. The antiangiogenic activity of NT-4 was probably mediated by binding to its receptor neogenin. Netrin-4 had a direct effect on neither in vitro apoptosis and proliferation of cultured LS174 cells nor the VEGF-induced acute increase in vascular permeability in vivo. We propose that NT-4 overexpression decreases tumor growth and carcinomatosis, probably via an antiangiogenic effect, underlying the potential therapeutic interest in NT-4 in the treatment of colorectal cancer growth and carcinomatosis.

Targeting the Tumor Microenvironment through mTOR Inhibition and Chemotherapy as Induction Therapy for Locally Advanced Head and Neck Squamous Cell Carcinoma: The CAPRA Study.

Mammalian target of rapamycin (mTOR) regulates cellular functions by integrating intracellular signals and signals from the tumor microenvironment (TME). The PI3K-AKT-mTOR pathway is activated in 70% of head and neck squamous cell carcinoma (HNSCC) and associated with poor prognosis. This phase I-II study investigated the effect of mTOR inhibition using weekly everolimus (30 mg for dose level 1, 50 mg for dose level 2) combined with weekly induction chemotherapy (AUC2 carboplatin and 60 mg/m2 paclitaxel) in treatment-naïve patients with locally advanced T3-4/N0-3 HNSCC. Patients received 9 weekly cycles before chemoradiotherapy. Objectives were safety and antitumor activity along with tissue and blood molecular biomarkers. A total of 50 patients were enrolled. Among 41 evaluable patients treated at the recommended dose of 50 mg everolimus weekly, tolerance was good and overall response rate was 75.6%, including 20 major responses (≥50% reduction in tumor size). A significant decrease in expression of p-S6K (p-value: 0.007) and Ki67 (p-value: 0.01) was observed in post-treatment tumor tissue. Pro-immunogenic cytokine release (Th1 cytokines IFN-γ, IL-2, and TNF-ß) was observed in the peripheral blood. The combination of everolimus and chemotherapy in HNSCC was safe and achieved major tumor responses. This strategy favorably impacts the TME and might be combined with immunotherapeutic agents.

Biomarkers in Hepatobiliary Cancers: What is Useful in Clinical Practice?

Hepatocellular carcinoma (HCC) and biliary tract cancers (BTC) exhibit a poor prognosis with 5-year overall survival rates around 15%, all stages combined. Most of these primary liver malignancies are metastatic at diagnostic, with only limited therapeutic options, relying mainly on systemic therapies. Treatment modalities are different yet partially overlapping between HCC and BTC. The complex molecular profile of BTC yields to several actionable therapeutic targets, contrary to HCC that remains the field of antiangiogenic drugs in non-molecularly selected patients. Immunotherapy is now validated in the first line in HCC in combination with bevacizumab, while clinical activity of single agent immunotherapy appears limited to a subset of patients in BTC, still poorly characterized, and combinations are currently under investigation. In this review, we provide a critical evaluation and grading of clinical relevance on (i) the main prognostic biomarkers in HCC and BTC, (ii) the main theragnostic biomarkers in both tumors, and lastly (iii) what is recommended in clinical practice.

Microbiome and pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) incidence and related-deaths are increasing worldwide. PDAC is characterized by poor prognosis due to late diagnosis, high metastatic capacity and resistance to therapy. This is partially due to its specific microenvironment, where the stroma is prominent over tumor cells. Besides the oral and gut microbiota, the intratumor microbiome, i.e. the bacterial and fungal microorganisms present within the tumor, was recently introduced as a new partner of the tumor microenvironment of PDAC modulating pancreatic carcinogenesis, intratumor immune infiltrates, and response to chemotherapy. In this review, we propose an overview of current knowledge about the roles of bacteria and fungi in PDAC development and biology, and discuss potential therapeutic implications.

Macrophages in the microenvironment of head and neck cancer: potential targets for cancer therapy.

The microenvironment of solid tumors has become a promising target for future therapies modulating immune cells. Patients with advanced head and neck cancer, which still portends a poor outcome, are particularly in need of innovative approaches. In oral squamous cell carcinoma, high density of tumor-associated macrophages (TAMs) appears consistently associated with poor prognosis, whereas data are currently limited for other head and neck sites. Several approaches to block TAMs have been investigated, including TAMs inactivation by means of the colony stimulating factor 1 (CSF-1)/CSF-1 receptor (CSF-1R) inhibitors or strategies to reprogram TAMs from M2 protumoral phenotype toward M1 antitumoral phenotype. This review focuses on both prognostic and therapeutic aspects related to TAMs in head and neck carcinomas.

Efficacy of aflibercept with FOLFOX and maintenance with fluoropyrimidine as first­line therapy for metastatic colorectal cancer: GERCOR VELVET phase II study.

Aflibercept in combination with 5­fluorouracil (5­FU)/irinotecan improves overall survival in the second­line therapy of patients with metastatic colorectal cancer (mCRC). In this study, we evaluated the effects of aflibercept in first­line therapy with FOLFOX followed by maintenance with fluoropyrimidine. VELVET was a prospective, single­arm multicenter phase II study (completed). Patients with previously untreated, unresectable, evaluable or measurable mCRC, with an age ≥18 years, and an ECOG performance status of 0­2 received 6 cycles of modified FOLFOX7 (5­FU/folinic acid and oxaliplatin) with aflibercept at 4 mg/kg every 2 weeks followed by maintenance therapy with fluoropyrimidine with aflibercept until disease progression or limiting toxicity. The reintroduction of oxaliplatin was performed at first progression. The primary endpoint was progression­free survival (PFS) at 6 months. From May, 2013 to May, 2014, 49 patients were included and 48 were evaluable for response. In total, 33 patients (67.4%) were alive without progression at 6 months. The Kaplan­Meier survival 6­month and 1­year PFS rates were 79.1 and 36.1%, respectively, and the median PFS was 9.3 months (95% CI, 8.3­12.5). The objective response rate was 59.2% (N=29/49). The most common (≥10%) grade 3­4 adverse events were hypertension (23%), fatigue (15%), neutropenia (12%), neuropathy (12%) and stomatitis (10%). Three (6%) treatment­related deaths occurred: One from stroke, one from pulmonary embolism and one from neutropenic sepsis. On the whole, this study demonstrates the efficacy of aflibercept in combination with an oxaliplatin­based regimen in the first­line therapy of patients with mCRC. A strict monitoring of blood pressure and immediate management of hypertension during therapy is mandatory.

Hepatectomy increases metastatic graft and growth in an immunocompetent murine model of peritoneal metastases.

BACKGROUND: Curative surgery of synchronous peritoneal metastases (PM) and colorectal liver metastases (LM) has been recently investigated as feasible option. When synchronous peritoneal and liver resection is not achievable, the sequence of the surgery remains unknown. Our hypothesis was that liver resection (LR) promotes peritoneal growth resulting in a non-resectable PM. We sought to analyse the effects of major LR and liver regeneration after hepatectomy in a murine model of PM and the associated angiogenesis. METHODS: Murine model of colorectal PM in Balb/C mice was developed by intraperitoneal injection of different CT-26 tumour cell concentrations. Five days after the injection, mice were randomized into three groups: 68% hepatectomy group, sham laparotomy and control group without surgery. On post-operative days 1, 5 and 20, PM was evaluated macroscopically, tumour growth and liver regeneration by immunohistochemistry, and angiogenesis by immunofluorescence. Circulating progenitor cells, plasmatic cytokines and digestive arterial blood flow velocity measurements were also analysed. RESULTS: Reproducible murine model of limited colorectal PM was obtained. Surgery induced PM increases and promoted neo-angiogenesis. Major hepatectomy influence the tumour growth in the late phase after surgery, the extent of extra-peritoneal metastasis and the increase of Ki-67 expression in the remnant liver. CONCLUSIONS: This animal model confirms the pro-tumoural and pro-angiogenic role of surgery, laparotomy and major LR, which promotes the increase of angiogenic factors and their participation in PM growth. These results suggest that peritoneal resection should be first step in the case of two-step liver and peritoneal surgery for patients with colorectal PM and LM.

Everolimus affects vasculogenic mimicry in renal carcinoma resistant to sunitinib.

Angiogenesis is hallmark of clear cell renal cell carcinogenesis. Anti-angiogenic therapies have been successful in improving disease outcome; however, most patients treated with anti-angiogenic agents will eventually progress. In this study we report that clear cell renal cell carcinoma was associated with vasculogenic mimicry in both mice and human with tumor cells expressing endothelial markers in the vicinity of tumor vessels. We show that vasculogenic mimicry was efficiently targeted by sunitinib but eventually associated with tumor resistance and a more aggressive phenotype both in vitro and in vivo. Re-challenging these resistant tumors in mice, we showed that second-line treatment with everolimus particularly affected vasculogenic mimicry and tumor cell differentiation compared to sorafenib and axitinib. Finally, our results highlighted the phenotypic and genotypic changes at the tumor cell and microenvironment levels during sunitinib response and progression and the subsequent improvement second-line therapies bring to the current renal cell carcinoma treatment paradigm.

Targeting the TGFß pathway for cancer therapy.

The TGFß signaling pathway has pleiotropic functions regulating cell growth, differentiation, apoptosis, motility and invasion, extracellular matrix production, angiogenesis, and immune response. TGFß signaling deregulation is frequent in tumors and has crucial roles in tumor initiation, development and metastasis. TGFß signaling inhibition is an emerging strategy for cancer therapy. The role of the TGFß pathway as a tumor-promoter or suppressor at the cancer cell level is still a matter of debate, due to its differential effects at the early and late stages of carcinogenesis. In contrast, at the microenvironment level, the TGFß pathway contributes to generate a favorable microenvironment for tumor growth and metastasis throughout all the steps of carcinogenesis. Then, targeting the TGFß pathway in cancer may be considered primarily as a microenvironment-targeted strategy. In this review, we focus on the TGFß pathway as a target for cancer therapy. In the first part, we provide a comprehensive overview of the roles played by this pathway and its deregulation in cancer, at the cancer cell and microenvironment levels. We go on to describe the preclinical and clinical results of pharmacological strategies to target the TGFß pathway, with a highlight on the effects on tumor microenvironment. We then explore the perspectives to optimize TGFß inhibition therapy in different tumor settings.

Targeting cancer cell metabolism in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of cancer death by 2030. Current therapeutic options are limited, warranting an urgent need to explore innovative treatment strategies. Due to specific microenvironment constraints including an extensive desmoplastic stroma reaction, PDAC faces major metabolic challenges, principally hypoxia and nutrient deprivation. Their connection with oncogenic alterations such as KRAS mutations has brought metabolic reprogramming to the forefront of PDAC therapeutic research. The Warburg effect, glutamine addiction, and autophagy stand as the most important adaptive metabolic mechanisms of cancer cells themselves, however metabolic reprogramming is also an important feature of the tumor microenvironment, having a major impact on epigenetic reprogramming and tumor cell interactions with its complex stroma. We present a comprehensive overview of the main metabolic adaptations contributing to PDAC development and progression. A review of current and future therapies targeting this range of metabolic pathways is provided.

State of the art and future directions of pancreatic ductal adenocarcinoma therapy.

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second cause of cancer-related death in 2030. PDAC is the poorest prognostic tumor of the digestive tract, with 80% of patients having advanced disease at diagnosis and 5-year survival rate not exceeding 7%. Until 2010, gemcitabine was the only validated therapy for advanced PDAC with a modest improvement in median overall survival as compared to best supportive care (5-6 vs 3 months). Multiple phase II-III studies have used various combinations of gemcitabine with other cytotoxics or targeted agents, most in vain, in attempt to improve this outcome. Over the past few years, the landscape of PDAC management has undergone major and rapid changes with the approval of the FOLFIRINOX and gemcitabine plus nab-paclitaxel regimens in patients with metastatic disease. These two active combination chemotherapy options yield an improved median overall survival (11.1 vs 8.5 months, respectively) thus making longer survival a reasonably achievable goal. This breakthrough raises some new clinical questions about the management of PDAC. Moreover, better knowledge of the environmental and genetic events that underpin multistep carcinogenesis and of the microenvironment surrounding cancer cells in PDAC has open new perspectives and therapeutic opportunities. In this new dynamic context of deep transformation in basic research and clinical management aspects of the disease, we gathered updated preclinical and clinical data in a multifaceted review encompassing the lessons learned from the past, the yet unanswered questions, and the most promising research priorities to be addressed for the next 5 years.

Effects of TGF-beta signalling inhibition with galunisertib (LY2157299) in hepatocellular carcinoma models and in ex vivo whole tumor tissue samples from patients.

Galunisertib (LY2157299) is a selective ATP-mimetic inhibitor of TGF-ß receptor (TßR)-I activation currently under clinical investigation in hepatocellular carcinoma (HCC) patients. Our study explored the effects of galunisertib in vitro in HCC cell lines and ex vivo on patient samples. Galunisertib was evaluated in HepG2, Hep3B, Huh7, JHH6 and SK-HEP1 cells as well as in SK-HEP1-derived cells tolerant to sorafenib (SK-Sora) and sunitinib (SK-Suni). Exogenous stimulation of all HCC cell lines with TGF-ß yielded downstream activation of p-Smad2 and p-Smad3 that was potently inhibited with galunisertib treatment at micromolar concentrations. Despite limited antiproliferative effects, galunisertib yielded potent anti-invasive properties. Tumor slices from 13 patients with HCC surgically resected were exposed ex vivo to 1 µM and 10 µM galunisertib, 5 µM sorafenib or a combination of both drugs for 48 hours. Galunisertib but not sorafenib decreased p-Smad2/3 downstream TGF-ß signaling. Immunohistochemistry analysis of galunisertib and sorafenib-exposed samples showed a significant decrease of the proliferative marker Ki67 and increase of the apoptotic marker caspase-3. In combination, galunisertib potentiated the effect of sorafenib efficiently by inhibiting proliferation and increasing apoptosis. Our data suggest that galunisertib may be active in patients with HCC and could potentiate the effects of sorafenib.