Dual inhibition using cabozantinib overcomes HGF/MET signaling mediated resistance to pan-VEGFR inhibition in orthotopic and metastatic neuroblastoma tumors

Zanzalintinib (XL092): a next-generation tyrosine kinase inhibitor-comprehensive review of early safety & efficacy data

INTRODUCTION

Zanzalintinib (XL092) is a next-generation anti-VEGFR-related multi-targeted TKI that exhibits immunomodulatory effects.

AREAS COVERED

This review explores preclinical and clinical data, along with the future directions associated with zanzalintinib and its combination with immune checkpoint inhibitors (ICIs).

EXPERT OPINION

In addition to its anti-VEGFR activity, zanzalintinib demonstrates potential synergistic effects with ICIs through its immunomodulatory impact, attributed to its inhibition of MET and TAM kinases. Recent preclinical studies provide compelling evidence supporting this synergistic potential. Furthermore, a recent phase 1 dose escalation study confirmed the tolerability of the zanzalintinib and anti-PDL1 combination without major safety concerns.Multiple ongoing clinical trials are investigating the combination of zanzalintinib and ICIs across various solid tumor types, including phase 3 studies for renal cell carcinoma, colorectal, and head and neck cancer. These trials aim to elucidate the therapeutic role of this new-generation TKI and ICI combination.However, the identification of reliable predictive biomarkers for the zanzalintinib and ICI combination presents significant challenges. Given the intricate nature of their mechanistic rationale and the difficulties in identifying reliable biomarkers for combined anti-angiogenesis and ICI therapies, addressing this challenge remains a priority for ongoing and future research.

Comprehensive quantifications of tumour microenvironment to predict the responsiveness to immunotherapy and prognosis for paediatric neuroblastomas

Treatment strategies for paediatric neuroblastoma as well as many other cancers are limited by the unfavourable tumour microenvironment (TME). In this study, the TMEs of neuroblastoma were grouped by their genetic signatures into four distinct subtypes: immune enriched, immune desert, non-proliferative and fibrotic. An Immune Score and a Proliferation Score were constructed based on the molecular features of the subtypes to quantify the immune microenvironment or malignancy degree of cancer cells in neuroblastoma, respectively. The Immune Score correlated with a patient's response to immunotherapy; the Proliferation Score was an independent prognostic biomarker for neuroblastoma and proved to be more accurate than the existing clinical predictors. This double scoring system was further validated and the conserved molecular pattern associated with immune landscape and malignancy degree was confirmed. Axitinib and BI-2536 were confirmed as candidate drugs for neuroblastoma by the double scoring system. Both in vivo and in vitro experiments demonstrated that axitinib-induced pyroptosis of neuroblastoma cells activated anti-tumour immunity and inhibited tumour growth; BI-2536 induced cell cycle arrest at the S phase in neuroblastoma cells. The comprehensive double scoring system of neuroblastoma may predict prognosis and screen for therapeutic strategies which could provide personalized treatments.

Design and biological evaluation of 3-substituted quinazoline-2,4(1H,3H)-dione derivatives as dual c-Met/VEGFR-2-TK inhibitors

The dual c-Met/vascular endothelial growth factor receptor 2 (VEGFR-2) TK inhibition is a good strategy to overcome therapeutic resistance to small molecules VEGFR-2 inhibitors. In this study, we designed 3-substituted quinazoline-2,4(1H,3H)-dione derivatives as dual c-Met/VEGFR-2 TK inhibitors. We introduced new synthetic methods for reported derivatives of 3-substituted quinazoline-2,4(1H,3H)-dione 2a-g, in addition to the preparation of some new derivatives namely, 3 and 4a-j. Three compounds namely, 2c, 4b, and 4e showed substantial amount of inhibition for both c-Met and VEGFR-2 TK (IC₅₀ range 0.052-0.084 µM). Both compounds 4b, 4e showed HB with highly conserved residue Asp1222 in the HB region of c-Met TK. For VEGFR-2 TK, compound 4b showed HB with a highly conserved residue Asp1046 in the HB region. Compound 4e showed HB with Glu885 and Asp1046. Moreover, in silico prediction of pharmacokinetic and physicochemical parameters of target compounds was carried out using SwissADME website. The quinazoline-2,4(1H,3H)-dione derivatives are promising antiproliferative candidates that require further optimisation.HighlightsNew 3-substituted quinazoline-2,4(1H,3H)-dione derivatives were synthesised and characterised.Compounds 4b and 4e showed higher cytotoxic activity than cabozantinib against HCT-116 colorectal cell lines.Both compounds 4b and 4e showed less toxicity to WI38 normal cell line compared to HCT 116 colon cancer cell line.Compound 4b was superior to cabozantinib in VEGFR-2 inhibition while compound 2c was equipotent to cabozantinib.Compounds 4b and 4e showed remarkable c-Met inhibitory activity.Compounds 4b and 4e arrested cell cycle and induced significant levels of apoptosis.In silico ADME prediction revealed high oral bioavailability and enhanced water solubility of target compounds as compared to cabozantinib.Target compounds interacted with both c-Met and VEGFR-2 active site in similar way to cabozantinib.

Targeting the RET tyrosine kinase in neuroblastoma: A review and application of a novel selective drug design strategy

The RET (REarranged during Transfection) gene, which encodes for a transmembrane receptor tyrosine kinase, is an established oncogene associated with the etiology and progression of multiple types of cancer. Oncogenic RET mutations and rearrangements resulting in gene fusions have been identified in many adult cancers, including medullary and papillary thyroid cancers, lung adenocarcinomas, colon and breast cancers, and many others. While genetic RET aberrations are much less common in pediatric solid tumors, increased RET expression has been shown to be associated with poor prognosis in children with solid tumors such as neuroblastoma, prompting an interest in RET inhibition as a form of therapy for these children. A number of kinase inhibitors currently in use for patients with cancer have RET inhibitory activity, but these inhibitors also display activity against other kinases, resulting in unwanted side effects and limiting their safety and efficacy. Recent efforts have been focused on developing more specific RET inhibitors, but due to high levels of conservation between kinase binding pockets, specificity remains a drug design challenge. Here, we review the background of RET as a potential therapeutic target in neuroblastoma tumors and the results of recent preclinical studies and clinical trials evaluating the safety and efficacy of RET inhibition in adults and children. We also present a novel approach to drug discovery leveraging the chemical phenomenon of atropisomerism to develop specific RET inhibitors and present preliminary data demonstrating the efficacy of a novel RET inhibitor against neuroblastoma tumor cells.

Antitumor effect of polyphyllin D on liver metastases of neuroblastoma

PURPOSE

We previously reported that polyphyllin D, a main component of the traditional Chinese medicinal herb Paris polyphylla, exhibited anticancer effects in vitro against human neuroblastoma cells. The aims of this investigation was to examine the presence or absence of in vivo anti-metastasis effects of polyphyllin D were to establish a liver metastasis model of neuroblastoma and to evaluate the anti-metastasis effects of polyphyllin D.

METHODS

Subcutaneous and intraperitoneal tumors, and metastasis models were established in immune-deficient BALB/c nude and BALB/c Rag-2/Jak3 double-deficient (BRJ) mice using the human neuroblastoma cell lines IMR-32, LA-N-2, or NB-69. For evaluating polyphyllin D activity, we used a mouse model of liver metastasis with the IMR-32 cells line injected through the tail vein. We analyzed the livers number and area of liver tumors in of the phosphate buffer solution- and polyphyllin D-treated groups.

RESULTS

Liver metastasis and intraperitoneal dissemination models were successfully established in immune-deficient BRJ mice using the three human neuroblastoma cell lines. In the liver metastasis, the model of IMR-32 cells, we found that polyphyllin D suppressed both the number and total area of metastatic foci the average number of metastatic foci, average focus areas, and number of cleaved caspase-3-positive cells were significantly lower in the polyphyllin D group (p = 0.016, 0.020, 0.043, respectively).

CONCLUSIONS

We developed a mouse models of neuroblastoma metastasis and demonstrated for the first time that polyphyllin D has an antitumor effect on neuroblastoma liver metastases.

Systematic review of the receptor tyrosine kinase superfamily in neuroblastoma pathophysiology

BACKGROUND

Neuroblastoma is a devastating disease accounting for 15% of all childhood cancer deaths. Yet, our understanding of key molecular drivers such as receptor tyrosine kinases (RTKs) in this pathology remains poorly clarified. Here, we provide a systematic analysis of the RTK superfamily in the context of neuroblastoma pathogenesis.

METHODS

Statistical correlations for all RTK family members' expression to neuroblastoma patient survival across 10 independent patient cohorts were annotated, synthesized, and ranked using the R2: Genomics Analysis and Visualization Platform. Gene expression of selected members across different cancer cell lines was further analyzed in the Cancer Cell Line Encyclopedia, part of the Cancer Dependency Map portal (depmap portal ( http://depmap.org )). Finally, we provide a detailed literature review for highly ranked candidates.

RESULTS

Our analysis defined two subsets of RTKs showing robust associations with either better or worse survival, constituting potential novel players in neuroblastoma pathophysiology, diagnosis, and therapy. We review the available literature regarding the oncogenic functions of these RTKs, their roles in neuroblastoma pathophysiology, and potential utility as therapeutic targets.

CONCLUSIONS

Our systematic analysis and review of the RTK superfamily in neuroblastoma pathogenesis provides a new resource to guide the research community towards focused efforts investigating signaling pathways that contribute to neuroblastoma tumor establishment, growth, and/or aggressiveness and targeting these druggable molecules in novel therapeutic strategies.

The hepatocyte growth factor/mesenchymal epithelial transition factor axis in high-risk pediatric solid tumors and the anti-tumor activity of targeted therapeutic agents

Clinical trials completed in the last two decades have contributed significantly to the improved overall survival of children with cancer. In spite of these advancements, disease relapse still remains a significant cause of death in this patient population. Often, increasing the intensity of current protocols is not feasible because of cumulative toxicity and development of drug resistance. Therefore, the identification and clinical validation of novel targets in high-risk and refractory childhood malignancies are essential to develop effective new generation treatment protocols. A number of recent studies have shown that the hepatocyte growth factor (HGF) and its receptor Mesenchymal epithelial transition factor (c-MET) influence the growth, survival, angiogenesis, and metastasis of cancer cells. Therefore, the c-MET receptor tyrosine kinase and HGF have been identified as potential targets for cancer therapeutics and recent years have seen a race to synthesize molecules to block their expression and function. In this review we aim to summarize the literature that explores the potential and biological rationale for targeting the HGF/c-MET pathway in common and high-risk pediatric solid tumors. We also discuss selected recent and ongoing clinical trials with these agents in relapsed pediatric tumors that may provide applicable future treatments for these patients.

Synthetic Heterocyclic Derivatives as Kinase Inhibitors Tested for the Treatment of Neuroblastoma

In the last few years, small molecules endowed with different heterocyclic scaffolds have been developed as kinase inhibitors. Some of them are being tested at preclinical or clinical levels for the potential treatment of neuroblastoma (NB). This disease is the most common extracranial solid tumor in childhood and is responsible for 10% to 15% of pediatric cancer deaths. Despite the availability of some treatments, including the use of very toxic cytotoxic chemotherapeutic agents, high-risk (HR)-NB patients still have a poor prognosis and a survival rate below 50%. For these reasons, new pharmacological options are urgently needed. This review focuses on synthetic heterocyclic compounds published in the last five years, which showed at least some activity on this severe disease and act as kinase inhibitors. The specific mechanism of action, selectivity, and biological activity of these drug candidates are described, when established. Moreover, the most remarkable clinical trials are reported. Importantly, kinase inhibitors approved for other diseases have shown to be active and endowed with lower toxicity compared to conventional cytotoxic agents. The data collected in this article can be particularly useful for the researchers working in this area.

Growth factor signaling predicts therapy resistance mechanisms and defines neuroblastoma subtypes

Neuroblastoma (NB) has a low frequency of recurrent mutations compared to other cancers, which hinders the development of targeted therapies and novel risk stratification strategies. Multikinase inhibitors have shown potential in treating high-risk NB, but their efficacy is likely impaired by the cancer cells' ability to adapt to these drugs through the employment of alternative signaling pathways. Based on the expression of 48 growth factor-related genes in 1189 NB tumors, we have developed a model for NB patient survival prediction. This model discriminates between stage 4 NB tumors with favorable outcomes (>80% overall survival) and very poor outcomes (<10%) independently from MYCN-amplification status. Using signaling pathway analysis and gene set enrichment methods in 60 NB patients with known therapy response, we identified signaling pathways, including EPO, NGF, and HGF, upregulated in patients with no or partial response. In a therapeutic setting, we showed that among six selected growth factors, EPO, and NGF showed the most pronounced protective effects in vitro against several promising anti-NB multikinase inhibitors: imatinib, dasatinib, crizotinib, cabozantinib, and axitinib. Mechanistically kinase inhibitors potentiated NB cells to stronger ERK activation by EPO and NGF. The protective action of these growth factors strongly correlated with ERK activation and was ERK-dependent. ERK inhibitors combined with anticancer drugs, especially with dasatinib, showed a synergistic effect on NB cell death. Consideration of growth factor signaling activity benefits NB outcome prediction and tailoring therapy regimens to treat NB.

Cabozantinib-based combination therapy for the treatment of hepatocellular carcinoma

OBJECTIVE

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer with limited treatment options. Cabozantinib, an orally bioavailable multikinase inhibitor is now approved by Food and Drug Administration (FDA) for HCC patients. We evaluated the therapeutic efficacy of cabozantinib, either alone or in combination, in vitro and in vivo.

DESIGN

Human HCC cell lines and HCC mouse models were used to assess the therapeutic efficacy and targeted molecular pathways of cabozantinib, either alone or in combination with the pan-mTOR inhibitor MLN0128 or the checkpoint inhibitor anti-PD-L1 antibody.

RESULTS

Cabozantinib treatment led to stable disease in c-Met/β-catenin and Akt/c-Met mouse HCC while possessing limited efficacy on Akt/Ras and c-Myc liver tumours. Importantly, cabozantinib effectively inhibited c-MET and ERK activity, leading to decreased PKM2 and increased p21 expression in HCC cells and in c-Met/β-catenin and Akt/c-Met HCC. However, cabozantinib was ineffective in inhibiting the Akt/mTOR cascade. Intriguingly, a strong inhibition of angiogenesis by cabozantinib occurred regardless of the oncogenic drivers. However, cabozantinib had limited impact on other tumour microenvironment parameters, including tumour infiltrating T cells, and did not induce programmed death-ligand 1 (PD-L1) expression. Combining cabozantinib with MLN0128 led to tumour regression in c-Met/β-catenin mice. In contrast, combined treatment with cabozantinib and the checkpoint inhibitor anti-PD-L1 antibody did not provide any additional therapeutic benefit in the four mouse HCC models tested.

CONCLUSION

c-MET/ERK/p21/PKM2 cascade and VEGFR2-induced angiogenesis are the primary targets of cabozantinib in HCC treatment. Combination therapies with cabozantinib and mTOR inhibitors may be effective against human HCC.

Antitumor effects of the multi-target tyrosine kinase inhibitor cabozantinib: a comprehensive review of the preclinical evidence

INTRODUCTION

Altered receptor tyrosine kinase (RTK) signaling contributes to tumorigenesis and suppression of immune-mediated destruction of cancer cells. Cabozantinib is an oral tyrosine kinase inhibitor that inhibits several RTKs involved in tumorigenesis, and is approved for the treatment of patients with progressive metastatic medullary thyroid cancer, advanced renal cell carcinoma, and hepatocellular carcinoma that has been previously treated with sorafenib.

AREAS COVERED

We present an up-to-date evaluation of preclinical evidence for RTK inhibition with cabozantinib, specifically VEGFR, MET, KIT, RET, AXL, FLT3, and associated antitumor effects. Preclinical investigations of cabozantinib in combination with other anticancer drugs are also reviewed.

EXPERT OPINION

Preclinical evidence shows that cabozantinib has antitumor activity against various cancer cells and exhibits synergy with other anticancer agents, including immune checkpoint inhibitors and hormone receptor or metabolic pathway inhibitors. Further optimization of cabozantinib treatment requires the identification of biomarkers of response and resistance, and exploration of complementary drug targets. Investigation of mechanisms of adaptive resistance, such as epithelial to mesenchymal transition (cancer intrinsic) and immunomodulation by the tumor microenvironment (cancer extrinsic), as well as identification of novel drug targets based on characterization of cancer stem cell metabolomic phenotypes, appear to be promising approaches.

Phase 1b/2 trial of tepotinib in sorafenib pretreated advanced hepatocellular carcinoma with MET overexpression

BACKGROUND

This Phase 1b/2 study evaluated tepotinib, a highly selective MET inhibitor, in US/European patients with sorafenib pretreated advanced hepatocellular carcinoma (aHCC) with MET overexpression.

METHODS

Eligible adults had aHCC, progression after ≥4 weeks of sorafenib, and, for Phase 2 only, MET overexpression. Tepotinib was administered once daily at 300 or 500 mg in Phase 1b ('3 + 3' design), and at the recommended Phase 2 dose (RP2D) in Phase 2. Primary endpoints were dose-liming toxicities (DLTs; Phase 1b) and 12-week investigator-assessed progression-free survival (PFS; Phase 2).

RESULTS

In Phase 1b (n = 17), no DLTs occurred and the RP2D was confirmed as 500 mg. In Phase 2 (n = 49), the primary endpoint was met: 12-week PFS was 63.3% (90% CI: 50.5-74.7), which was significantly greater than the predefined null hypothesis of ≤15% (one-sided binomial exact test: P < 0.0001). Median time to progression was 4 months. In Phase 2, 28.6% of patients had treatment-related Grade ≥3 adverse events, including peripheral oedema and lipase increase (both 6.1%).

CONCLUSIONS

Tepotinib was generally well tolerated and the RP2D (500 mg) showed promising efficacy and, therefore, a positive benefit-risk balance in sorafenib pretreated aHCC with MET overexpression.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02115373.

When the MET receptor kicks in to resist targeted therapies

Although targeted therapies have increased the life expectancy of patients with druggable molecular alterations directly involved in tumor development, the efficacy of these therapies is limited by acquired resistances leading to treatment failure. Most targeted therapies, including ones exploiting therapeutic antibodies and kinase inhibitors, are directed against receptor tyrosine kinases (RTKs) or major signaling hubs. Resistances to these therapies arise when inhibition of these targets is bypassed through activation of alternative signaling pathways. In recent years, activation of the receptor tyrosine kinase MET has been shown to promote resistance to various targeted therapies. This casts MET as important actor in resistance. In this review, we describe how the MET receptor triggers resistance to targeted therapies against RTKs such as EGFR, VEGFR, and HER2 and against signaling hubs such as BRAF. We also describe how MET can be its own resistance factor, as illustrated by on-target resistance of lung tumors harboring activating mutations causing MET exon 14 skipping. Interestingly, investigation of all these situations reveals functional physiological relationships between MET and the target of the therapy to which the cancer becomes resistant, suggesting that resistance stems from preexisting mechanisms. Identification of MET as a resistance factor opens the way to co-treatment strategies that are being tested in current clinical trials.

Mesenchymal Epithelial Transition Factor Signaling in Pediatric Nervous System Tumors: Implications for Malignancy and Cancer Stem Cell Enrichment

Malignant nervous system cancers in children are the most devastating and worrisome diseases, specifically due to their aggressive nature and, in some cases, inoperable location in critical regions of the brain and spinal cord, and the impermeable blood-brain barrier that hinders delivery of pharmaco-therapeutic compounds into the tumor site. Moreover, the delicate developmental processes of the nervous system throughout the childhood years adds another limitation to the therapeutic modalities and doses used to treat these malignant cancers. Therefore, pediatric oncologists are charged with the daunting responsibility of attempting to deliver effective cures to these children, yet with limited doses of the currently available therapeutic options in order to mitigate the imminent neurotoxicity of radio- and chemotherapy on the developing nervous system. Various studies reported that c-Met/HGF signaling is affiliated with increased malignancy and stem cell enrichment in various cancers such as high-grade gliomas, high-risk medulloblastomas, and MYCN-amplified, high-risk neuroblastomas. Therapeutic interventions that are utilized to target c-Met signaling in these malignant nervous system cancers have shown benefits in basic translational studies and preclinical trials, but failed to yield significant clinical benefits in patients. While numerous pre-clinical data reported promising results with the use of combinatorial therapy that targets c-Met with other tumorigenic pathways, therapeutic resistance remains a problem, and long-term cures are rare. The possible mechanisms, including the overexpression and activation of compensatory tumorigenic mechanisms within the tumors or ineffective drug delivery methods that may contribute to therapeutic resistance observed in clinical trials are elaborated in this review.

Cabozantinib for relapsed neuroblastoma: Single institution case series

Relapsed high-risk neuroblastoma has few effective therapies currently available or in development. Cabozantinib is an Food and Drug Administration approved multitargeted tyrosine kinase inhibitor for select adult malignancies with preclinical data suggesting efficacy against neuroblastoma. A safe and tolerable dose has been identified for children, but its efficacy remains unknown. We describe four children with relapsed metastatic neuroblastoma treated with cabozantinib. All four patients had extended disease control (two complete responsesfor >12 months, 2 stable disease >6 months) with manageable predictable toxicities requiring dose reduction in two patients. We discuss the potential for the use of cabozantinib in neuroblastoma.

Endothelial Colony-Forming Cell Function Is Reduced During HIV Infection

BACKGROUND

Human immunodeficiency virus (HIV) may be related to cardiovascular disease through monocyte activation-associated endothelial dysfunction.

METHODS

Blood samples from 15 HIV-negative participants (the uninfected group), 8 HIV-positive participants who were not receiving antiretroviral therapy (ART) (the infected, untreated group), and 15 HIV-positive participants who were receiving ART (the infected, treated group) underwent flow cytometry of endothelial colony-forming cells (ECFCs) and monocyte proportions. IncuCyte live cell imaging of 8 capillary proliferative capacity parameters were obtained from cord blood ECFCs treated with participant plasma.

RESULTS

The ECFC percentage determined by flow cytometry was not different between the study groups; however, values of the majority of capillary proliferative capacity parameters (ie, cell area, network length, network branch points, number of networks, and average tube width uniformity) were significantly lower in infected, untreated participants as compared to values for uninfected participants or infected, treated participants (P < .00625 for all comparisons). CD14+CD16+ intermediate monocytes and soluble CD163 were significantly and negatively correlated with several plasma-treated, cord blood ECFC proliferative capacity parameters in the combined HIV-positive groups but not in the uninfected group.

CONCLUSIONS

Cord blood ECFC proliferative capacity was significantly impaired by plasma from infected, untreated patients, compared with plasma from uninfected participants and from infected, treated participants. Several ECFC functional parameters were adversely associated with monocyte activation in the HIV-positive groups, thereby suggesting a mechanism by which HIV-related inflammation may impair vascular reparative potential and consequently increase the risk of cardiovascular disease during HIV infection.

Developing preclinical models of neuroblastoma: driving therapeutic testing

Despite advances in cancer therapeutics, particularly in the area of immuno-oncology, successful treatment of neuroblastoma (NB) remains a challenge. NB is the most common cancer in infants under 1 year of age, and accounts for approximately 10% of all pediatric cancers. Currently, children with high-risk NB exhibit a survival rate of 40–50%. The heterogeneous nature of NB makes development of effective therapeutic strategies challenging. Many preclinical models attempt to mimic the tumor phenotype and tumor microenvironment. In vivo mouse models, in the form of genetic, syngeneic, and xenograft mice, are advantageous as they replicated the complex tumor-stroma interactions and represent the gold standard for preclinical therapeutic testing. Traditional in vitro models, while high throughput, exhibit many limitations. The emergence of new tissue engineered models has the potential to bridge the gap between in vitro and in vivo models for therapeutic testing. Therapeutics continue to evolve from traditional cytotoxic chemotherapies to biologically targeted therapies. These therapeutics act on both the tumor cells and other cells within the tumor microenvironment, making development of preclinical models that accurately reflect tumor heterogeneity more important than ever. In this review, we will discuss current in vitro and in vivo preclinical testing models, and their potential applications to therapeutic development.

Cabozantinib (XL184) and R428 (BGB324) Inhibit the Growth of Esophageal Squamous Cell Carcinoma (ESCC)

Esophageal squamous cell carcinoma (ESCC) is a deadly disease for which no effective targeted therapeutic agent has been approved. Both AXL and c-MET have been reported to be independent prognostic factors for ESCC. Thus, inhibitors of AXL/c-MET might have great potential as targeted therapy for ESCC. In the current study, we evaluated the therapeutic potential of the AXL/c-MET selective inhibitors, R428 and cabozantinib, in cell and mouse xenograft models. We demonstrated that both R428 and cabozantinib significantly inhibited the growth of CE81T and KYSE-70 ESCC cells and showed by wound-healing assay that they both inhibited ESCC cell migration. In the animal model, ESCC xenograft models were established by injecting KYSE-70 cells with Matrigel into the upper back region of NOD-SCID male mice followed by treatment with vehicle control, R428 (50 mg/kg/day), cisplatin (1.0 mg/kg), or cabozantinib (30 mg/kg/day) for the indicated number of days. R428 alone significantly inhibited ESCC tumor growth compared to the vehicle; however, no synergistic effect with cisplatin was observed. Notably, the dramatic efficacy of cabozantinib alone was observed in the mouse xenograft model. Collectively, our study demonstrated that both cabozantinib and R428 inhibit ESCC growth in cell and xenograft models. The results reveal the great potential of using cabozantinib for targeted therapy of ESCC.

MRI Imaging of the Hemodynamic Vasculature of Neuroblastoma Predicts Response to Antiangiogenic Treatment

Childhood neuroblastoma is a hypervascular tumor of neural origin, for which antiangiogenic drugs are currently being evaluated; however, predictive biomarkers of treatment response, crucial for successful delivery of precision therapeutics, are lacking. We describe an MRI-pathologic cross-correlative approach using intrinsic susceptibility (IS) and susceptibility contrast (SC) MRI to noninvasively map the vascular phenotype in neuroblastoma Th-MYCN transgenic mice treated with the vascular endothelial growth factor receptor inhibitor cediranib. We showed that the transverse MRI relaxation rate R 2* (second-1) and fractional blood volume (fBV, %) were sensitive imaging biomarkers of hemorrhage and vascular density, respectively, and were also predictive biomarkers of response to cediranib. Comparison with MRI and pathology from patients with MYCN-amplified neuroblastoma confirmed the high degree to which the Th-MYCN model vascular phenotype recapitulated that of the clinical phenotype, thereby supporting further evaluation of IS- and SC-MRI in the clinic. This study reinforces the potential role of functional MRI in delivering precision medicine to children with neuroblastoma. SIGNIFICANCE: This study shows that functional MRI predicts response to vascular-targeted therapy in a genetically engineered murine model of neuroblastoma.

Activation of hepatocyte growth factor/MET signaling initiates oncogenic transformation and enhances tumor aggressiveness in the murine prostate

Emerging evidence has shown that the hepatocyte growth factor (HGF) and its receptor, MET proto-oncogene, receptor tyrosine kinase (MET), promote cell proliferation, motility, morphogenesis, and angiogenesis. Whereas up-regulation of MET expression has been observed in aggressive and metastatic prostate cancer, a clear understanding of MET function in prostate tumorigenesis remains elusive. Here, we developed a conditional Met transgenic mouse strain, H11 ^Met/+ :PB-Cre4, to mimic human prostate cancer cells with increased MET expression in the prostatic luminal epithelium. We found that these mice develop prostatic intraepithelial neoplasia after HGF administration. To further assess the biological role of MET in prostate cancer progression, we bred H11 ^Met/+ /Pten^LoxP/LoxP:PBCre4 compound mice, in which transgenic Met expression and deletion of the tumor suppressor gene Pten occurred simultaneously only in prostatic epithelial cells. These compound mice exhibited accelerated prostate tumor formation and invasion as well as increased metastasis compared with Pten^LoxP/LoxP:PB-Cre4 mice. Moreover, prostatic sarcomatoid carcinomas and lesions resembling the epithelial-to-mesenchymal transition developed in tumor lesions of the compound mice. RNA-Seq and qRT-PCR analyses revealed a robust enrichment of known tumor progression and metastasis-promoting genes in samples isolated from H11 ^Met/+ /Pten^LoxP/LoxP:PB-Cre4 compound mice compared with those from Pten^LoxP/LoxP:PB-Cre4 littermate controls. HGF-induced cell proliferation and migration also increased in mouse embryonic fibroblasts (MEFs) from animals with both Met transgene expression and Pten deletion compared with Pten-null MEFs. The results from these newly developed mouse models indicate a role for MET in hastening tumorigenesis and metastasis when combined with the loss of tumor suppressors.

The role of tumor microenvironment in resistance to anti-angiogenic therapy

Anti-angiogenic therapy has been demonstrated to increase progression-free survival in patients with many different solid cancers. Unfortunately, the benefit in overall survival is modest and the rapid emergence of drug resistance is a significant clinical problem. Over the last decade, several mechanisms have been identified to decipher the emergence of resistance. There is a multitude of changes within the tumor microenvironment (TME) in response to anti-angiogenic therapy that offers new therapeutic opportunities. In this review, we compile results from contemporary studies related to adaptive changes in the TME in the development of resistance to anti-angiogenic therapy. These include preclinical models of emerging resistance, dynamic changes in hypoxia signaling and stromal cells during treatment, and novel strategies to overcome resistance by targeting the TME.

The untold stories of the speech gene, the FOXP2 cancer gene

FOXP2 encodes a transcription factor involved in speech and language acquisition. Growing evidence now suggests that dysregulated FOXP2 activity may also be instrumental in human oncogenesis, along the lines of other cardinal developmental transcription factors such as DLX5 and DLX6 [1-4]. Several FOXP familymembers are directly involved during cancer initiation, maintenance and progression in the adult [5-8]. This may comprise either a pro-oncogenic activity or a deficient tumor-suppressor role, depending upon cell types and associated signaling pathways. While FOXP2 is expressed in numerous cell types, its expression has been found to be down-regulated in breast cancer [9], hepatocellular carcinoma [8] and gastric cancer biopsies [10]. Conversely, overexpressed FOXP2 has been reported in multiple myelomas, MGUS (Monoclonal Gammopathy of Undetermined Significance), several subtypes of lymphomas [5,11], as well as in neuroblastomas [12] and ERG fusion-negative prostate cancers [13]. According to functional evidences reported in breast cancer [9] and survey of recent transcriptomic and proteomic analyses of different tumor biopsies, we postulate that FOXP2 dysregulation may play a main role throughout cancer initiation and progression. In some cancer conditions, FOXP2 levels are now considered as a critical diagnostic marker of neoplastic cells, and in many situations, they even bear strong prognostic value [5]. Whether FOXP2 may further become a therapeutic target is an actively explored lead. Knowledge reviewed here may help improve our understanding of FOXP2 roles during oncogenesis and provide cues for diagnostic, prognostic and therapeutic analyses.

Systemic treatments for hepatocellular carcinoma: challenges and future perspectives

Sorafenib has been the only approved systemic treatment of hepatocellular carcinoma (HCC) for almost a decade. Recently, two new drugs showed positive results in two Phase III studies. The RESORCE trial identified regorafenib as a valid second-line treatment for patients progressing to sorafenib, the REFLECT trial showed that lenvatinib is noninferior to sorafenib as front-line treatment. Following these trials, the therapeutic scenario will be dominated by anti-VEGFR drugs, with three different molecules showing a proven anticancer activity. Some open problems still remain and different immunotherapy trials are underway, following promising preliminary results. In this review we analyze: the most recent advancements about patients treated with sorafenib; the results of RESORCE and REFLECT trials; and the ongoing Phase III clinical trials. Finally, we discuss how they could address the current problems and possibly reshape the future of the systemic treatments for HCC.

Overexpression of miR-101 promotes TRAIL-induced mitochondrial apoptosis in papillary thyroid carcinoma by targeting c-met and MCL-1

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) induces apoptosis in malignant cells, but not in normal cells. As papillary thyroid carcinoma cells broadly expressed TRAIL receptors (death receptor 4 and death receptor 5) on their surface, TRAIL is considered as a promising drug for treatment of papillary thyroid carcinoma. However, resistance to TRAIL still be a big obstacle to achieve a satisfactory effect for cancer therapy. Here, we found that overexpression of miR-101 was able to sensitize papillary thyroid carcinoma cells to TRAIL treatment in vitro and in vivo. Mechanically, we found that genes of c-met and MCL-1 were the targets of miR-101. Overexpression of miR-101 in TPC-1 significantly decreased the cellular protein levels of c-met and MCL-1, and thus inhibiting the PI3K/AKT pathway and reducing the resistance to TRAIL-induced mitochondrial apoptosis. Enforced expression of either c-met or MCL-1 could partially inhibit the miR-101 promoted apoptosis in TRAIL-treated TPC-1 cells. These results indicated that miR-101-c-met/MCL-1 axis determined the sensitivity of TRAIL to thyroid cancer in some extent. Combination with TRAIL and miR-101 may represent a novel approach to kill papillary thyroid carcinoma cells efficiently.

Postsorafenib systemic treatments for hepatocellular carcinoma: questions and opportunities after the regorafenib trial

The search for systemic therapies for hepatocellular carcinoma has been characterized by difficulties and failures. Despite recent progresses, many issues are still to be settled. In particular, the development of drugs inhibiting different neoplastic pathways remains a priority for patients intolerant or resistant to antiangiogenic drugs. This task may be daunting, as previous failures extensively demonstrated. We aimed to identify the future perspective of postsorafenib trials analyzing the strengths and the critical points of past and currently undergoing studies, in the light of the most recent evidences in the field. We identified various points (including stratification, biomarkers, end points, radiologic criteria of response, treatment beyond radiologic progression) that should be considered by future trials to reduce the risks of failure.