Foretinib inhibits angiogenesis, lymphangiogenesis and tumor growth of pancreatic cancer in vivo by decreasing VEGFR-2/3 and TIE-2 signaling

Recent updates on potential of VEGFR-2 small-molecule inhibitors as anticancer agents

The vascular endothelial growth factor receptor (VEGFR) system is the key component for controlling angiogenesis in cancer cells. Blocking vascular endothelial growth factor receptor 2 (VEGFR2) signalling is one of the most promising approaches to hindering angiogenesis and the subsequent growth of cancer cells. The USFDA-approved small-molecule drugs targeting VEGFR-2 are developing drug resistance over the course of chemotherapy, and cardiac-related side effects are consistently being reported; hence, there is an urgent need for more safe and effective anticancer molecules. The present review focuses on the structure and physiology of VEGFR-2 and its involvement in the progression of cancer cells. The recent updates from the last five years through papers and patents on structure-activity relationships, pharmacophoric attributes, molecular docking interactions, antiangiogenic assays, cancer cell line studies, and the potencies (IC50) of VEGFR-2 inhibitors are discussed herein. The common structural framework requirements, such as the Asp-Phe-Gly (DFG) motif of VEGFR-2 interacting with the HBD-HBA region in the ligand molecules, the central aryl ring occupying the linker region, and a variety of bio-isosteres, can enhance activity against VEGFR-2. At one end, the heteroaryl moiety is essential for interaction within the ATP-binding site of VEGFR-2, while the terminal hydrophobic tail occupies the allosteric binding site. Three to five bond spacers between the heteroaryl and HBD-HBA regions provided a better result towards VEGFR-2 inhibition, mirroring the behaviors of standard drugs. The in-depth analysis of recent updates on VEGFR-2 inhibitors presented in this paper will help prospective synthetic and medicinal chemists to discover new lead molecules for the treatment of various cancers.

Clinical and Preclinical Targeting of Oncogenic Pathways in PDAC: Targeted Therapeutic Approaches for the Deadliest Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death worldwide. It is commonly diagnosed in advanced stages and therapeutic interventions are typically constrained to systemic chemotherapy, which yields only modest clinical outcomes. In this review, we examine recent developments in targeted therapy tailored to address distinct molecular pathway alteration required for PDAC. Our review delineates the principal signaling pathways and molecular mechanisms implicated in the initiation and progression of PDAC. Subsequently, we provide an overview of prevailing guidelines, ongoing investigations, and prospective research trajectories related to targeted therapeutic interventions, drawing insights from randomized clinical trials and other pertinent studies. This review focus on a comprehensive examination of preclinical and clinical data substantiating the efficacy of these therapeutic modalities, emphasizing the potential of combinatorial regimens and novel therapies to enhance the quality of life for individuals afflicted with PDAC. Lastly, the review delves into the contemporary application and ongoing research endeavors concerning targeted therapy for PDAC. This synthesis serves to bridge the molecular elucidation of PDAC with its clinical implications, the evolution of innovative therapeutic strategies, and the changing landscape of treatment approaches.

Small Molecule Tyrosine Kinase Inhibitors (TKIs) for Glioblastoma Treatment

In the last decade, many small molecules, usually characterized by heterocyclic scaffolds, have been designed and synthesized as tyrosine kinase inhibitors (TKIs). Among them, several compounds have been tested at preclinical and clinical levels to treat glioblastoma multiforme (GBM). GBM is the most common and aggressive type of cancer originating in the brain and has an unfavorable prognosis, with a median survival of 15-16 months and a 5-year survival rate of 5%. Despite recent advances in treating GBM, it represents an incurable disease associated with treatment resistance and high recurrence rates. For these reasons, there is an urgent need for the development of new pharmacological agents to fight this malignancy. In this review, we reported the compounds published in the last five years, which showed promising activity in GBM preclinical models acting as TKIs. We grouped the compounds based on the targeted kinase: first, we reported receptor TKIs and then, cytoplasmic and peculiar kinase inhibitors. For each small molecule, we included the chemical structure, and we schematized the interaction with the target for some representative compounds with the aim of elucidating the mechanism of action. Finally, we cited the most relevant clinical trials.

The possible dual role of Ang-2 in the prognosis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) features a dense desmoplastic stroma, which raises the intratumoral interstitial pressure leading to vascular collapse and hypoxia, inducing angiogenesis. Vascular growth factors, such as vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2), increase in PDAC. A high VEGF and a high circulating Ang-2 associate with shorter survival in PDAC. In addition to the circulatory Ang-2, PDAC endothelial and epithelial cells express Ang-2. No correlation between tumor epithelial nor endothelial cell Ang-2 expression and survival has been published. We aimed to examine Ang-2 expression and survival. This study comprised PDAC surgical patients at Helsinki University Hospital in 2000-2013. Ang-2 immunohistochemistry staining was completed on 168 PDAC patient samples. Circulating Ang-2 levels were measured using ELISA in the sera of 196 patients. Ang-2 levels were assessed against clinical data and patient outcomes. A low tumor epithelial Ang-2 expression predicted shorter disease-specific survival (DSS) compared with a high expression (p = 0.003). A high serum Ang-2 associated with shorter DSS compared with a low circulating Ang-2 (p = 0.016). Ang-2 seemingly plays a dual role in PDAC survival. Further studies are needed to determine the mechanisms causing tumor cell Ang-2 expression and its positive association with survival.

Nanoparticles targeting Sialyl-Tn for efficient tyrosine kinase inhibitor delivery in gastric cancer

Gastric cancer (GC) is the fourth leading cause of cancer-related deaths worldwide and, therefore, it is urgent to develop new and more efficient therapeutic approaches. Foretinib (FRT) is an oral multikinase inhibitor targeting MET (hepatocyte growth factor receptor) and RON (recepteur d'origine nantais) receptor tyrosine kinases (RTKs) that has been used in clinical trials for several solid tumors. Targeted uptake of therapeutic polymeric nanoparticles (NPs) represents a powerful approach in cancer cell drug delivery. Previously, a nanodelivery system composed of polymeric NPs functionalized with B72.3 antibody, which targets the tumor-associated antigen Sialyl-Tn (STn), has been developed. Herein, these NPs were loaded with FRT to evaluate its capacity in delivering the drug to multicellular tumors spheroids (MCTS) and mouse models. The data indicated that B72.3 functionalized FRT-loaded PLGA-PEG-COOH NPs (NFB72.3) specifically target gastric MCTS expressing the STn glycan (MKN45 SimpleCell (SC) cells), leading to a decrease in phospho-RTKs activation and reduced cell viability. In vivo evaluation using MKN45 SC xenograft mice revealed that NFB72.3 were able to decrease tumor growth, reduce cell proliferation and tumor necrosis. NFB72.3-treated tumors also showed inactivation of phospho-MET and phospho-RON. This study demonstrates the value of using NPs targeting STn for FRT delivery, highlighting its potential as a therapeutic application in GC. STATEMENT OF SIGNIFICANCE: Despite the advances in gastric cancer therapeutics, it remains one of the diseases with the highest incidence and mortality in the world. Combining targeted therapies with a controlled drug release is an attractive strategy to reduce drug cytotoxic effects and improve specific drug delivery efficiency to the cancer cells. Thus, we developed nanoparticles loaded with a tyrosine kinase inhibitor and targeting a specific tumor glycan exclusive of cancer cells. In in vivo gastric cancer xenograft mice models, these nanoparticles efficiently reduced tumor growth, cell proliferation and tumor necrosis area and inactivated phosphorylation of targeting receptors. This approach represents an innovative therapeutic strategy with high impact in gastric cancer.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

Modeling lymphangiogenesis: Pairing in vitro and in vivo metrics

Lymphangiogenesis is the mechanism by which the lymphatic system develops and expands new vessels facilitating fluid drainage and immune cell trafficking. Models to study lymphangiogenesis are necessary for a better understanding of the underlying mechanisms and to identify or test new therapeutic agents that target lymphangiogenesis. Across the lymphatic literature, multiple models have been developed to study lymphangiogenesis in vitro and in vivo. In vitro, lymphangiogenesis can be modeled with varying complexity, from monolayers to hydrogels to explants, with common metrics for characterizing proliferation, migration, and sprouting of lymphatic endothelial cells (LECs) and vessels. In comparison, in vivo models of lymphangiogenesis often use genetically modified zebrafish and mice, with in situ mouse models in the ear, cornea, hind leg, and tail. In vivo metrics, such as activation of LECs, number of new lymphatic vessels, and sprouting, mirror those most used in vitro, with the addition of lymphatic vessel hyperplasia and drainage. The impacts of lymphangiogenesis vary by context of tissue and pathology. Therapeutic targeting of lymphangiogenesis can have paradoxical effects depending on the pathology including lymphedema, cancer, organ transplant, and inflammation. In this review, we describe and compare lymphangiogenic outcomes and metrics between in vitro and in vivo studies, specifically reviewing only those publications in which both testing formats are used. We find that in vitro studies correlate well with in vivo in wound healing and development, but not in the reproductive tract or the complex tumor microenvironment. Considerations for improving in vitro models are to increase complexity with perfusable microfluidic devices, co-cultures with tissue-specific support cells, the inclusion of fluid flow, and pairing in vitro models of differing complexities. We believe that these changes would strengthen the correlation between in vitro and in vivo outcomes, giving more insight into lymphangiogenesis in healthy and pathological states.

Foretinib Is Effective against Triple-Negative Breast Cancer Cells MDA-MB-231 In Vitro and In Vivo by Down-Regulating p-MET/HGF Signaling

This study investigated the antitumor effects of foretinib on triple-negative breast cancer cells MDA-MB-231 xenograft tumors in vivo underlying phosphorylated mesenchymal to epithelial transition (p-MET)/ hepatocyte growth factor (HGF)-related mechanism, as well as its pharmacokinetic characteristics. The MDA-MB-231 human breast cancer cell line was used for in vitro experiments, and the tumor xenograft model was established for in vivo experiments. MDA-MB-231 xenograft mice received oral foretinib (15 or 50 mg/kg/day) or vehicle for 18 days. The xenograft tumors were collected. Protein expressions of p-MET and HGF were examined with Western blotting and immunohistochemical staining. The mRNA expression of MET was examined with real-time PCR. Blood samples were collected from the mice treated with foretinib under different doses of 2, 10, and 50 mg/kg, and the pharmacokinetic profiles of foretinib were evaluated. We found that foretinib treatment caused a significant inhibition in tumor growth in a dose-dependent manner, whereas the continuous administration did not result in weight loss in treated nude mice. In both MDA-MB-231 cells and xenograft tumors, foretinib suppressed the expression of p-MET and HGF. These findings reveal that the decrease of p-MET and HGF may play an important role in the anti-breast cancer properties of foretinib.

Pancreatic Cancer: Beyond Brca Mutations

Pancreatic cancer is the fourth-leading cause of cancer-related deaths worldwide. The outcomes in patients with pancreatic cancer remain unsatisfactory. In the current review, we summarize the genetic and epigenetic architecture of metastatic pancreatic cancer beyond the BRCA mutations, focusing on the genetic alterations and the molecular pathology in pancreatic cancer. This review focuses on the molecular targets for the treatment of pancreatic cancer, with a correlation to future treatments. The potential approach addressed in this review may lead to the identification of a subset of patients with specific biological behaviors and treatment responses.

Effect of crosstalk among conspirators in tumor microenvironment on niche metastasis of gastric cancer

In Traditional Chinese medicine, the metaphoric views of the human body are based on observations of nature guided by the theory of "Yin-Yang". The direct meanings of yin and yang are the bright and dark sides of an object, which often represent a wider range of opposite properties. When we shifted our view to gastric cancer (GC), we found that there are more distinctive Yin and Yang features in the mechanism of GC development and metastasis, which is observed in many mechanisms such as GC metastasis, immune escape, and stem cell homing. When illustrating this process from the yin-yang perspective, categorizing different cells in the tumor microenvironment enables new and different perspectives to be put forward on the mechanism and treatment of GC metastasis.

Identify Multiple Gene-Drug Common Modules Via Constrained Graph Matching

Identifying gene-drug interactions is vital to understanding biological mechanisms and achieving precise drug repurposing. High-throughput technologies produce a large amount of pharmacological and genomic data, providing an opportunity to explore the associations between oncogenic genes and therapeutic drugs. However, most studies only focus on "one-to-one" or "one-to-many" interactions, ignoring the multivariate patterns between genes and drugs. In this article, a high-order graph matching model with hypergraph constraints is proposed to discover the gene-drug common regulatory modules. Moreover, the prior knowledge is formulated into hypergraph constraints to reveal their multiple correspondences, penalizing the tensor matching process. The experimental results on the synthetic data demonstrate the proposed model is robust to noise contamination and outlier corruption, achieving a better performance than four state-of-the-art methods. We then evaluate the statistical power of our proposed method on the pharmacogenomics data. Our identified gene-drug common modules not only show significantly enriched pathways associated with cancer but also manifest the highly close gene-drug interactions.

Foretinib mitigates cutaneous nerve fiber loss in experimental diabetic neuropathy

Diabetes is by far, the most common cause of neuropathy, inducing neurodegeneration of terminal sensory nerve fibers associated with loss of sensation, paresthesia, and persistent pain. Foretinib prevents die-back degeneration in cultured sensory and sympathetic neurons by rescuing mitochondrial activity and has been proven safe in prospective clinical trials. Here we aimed at investigating a potential neuroprotective effect of Foretinib in experimental diabetic neuropathy. A mouse model of streptozotocin induced diabetes was used that expresses yellow fluorescent protein (YFP) in peripheral nerve fibers under the thy-1 promoter. Streptozotocin-injected mice developed a stable diabetic state (blood glucose > 270 mg/dl), with a significant reduction of intraepidermal nerve fiber density by 25% at 5 weeks compared to the non-diabetic controls. When diabetic mice were treated with Foretinib, a significantly greater volume of the cutaneous nerve fibers (67.3%) in the plantar skin was preserved compared to vehicle treated (37.8%) and non-treated (44.9%) diabetic mice while proximal nerve fiber morphology was not affected. Our results indicate a neuroprotective effect of Foretinib on cutaneous nerve fibers in experimental diabetic neuropathy. As Foretinib treated mice showed greater weight loss compared to vehicle treated controls, future studies may define more sustainable treatment regimen and thereby may allow patients to take advantage of this neuroprotective drug in chronic neurodegenerative diseases like diabetic neuropathy.

LRG1 in pancreatic cancer cells promotes inflammatory factor synthesis and the angiogenesis of HUVECs by activating VEGFR signaling

BACKGROUND

This study aimed to investigate the roles of leucine-rich alpha-2-glycoprotein 1 (LRG1) in regulating angiogenesis during pancreatic cancer (PC) pathogenesis.

METHODS

LRG1 expression in tissues was detected by qRT-PCR and immunohistochemistry. LRG1 in BxPC-3 and Capan-2 cells was knocked down or overexpressed. Cell viability and the migration and invasion abilities of cells were analyzed using the Cell Counting Kit-8 (CCK-8) assay and Transwell system, respectively. Interleukin-1 beta (IL-1β), IL-18, and vascular endothelial growth factor A (VEGFA) contents in cell culture were measured by ELISA, and the angiogenesis of HUVECs was assessed by the in vitro tube formation assay. In vitro LRG1 expression in BxPC-3 and Capan-2 cells was determined using immunofluorescence.

RESULTS

The results showed that LRG1 expression was significantly increased in pancreatic cancer tissues and cell lines. LRG1 knockdown inhibited the viability, migration, invasion, and IL-1β and IL-18 synthesis of BxPC-3 and Capan-2 cells. VEGFA synthesis in BxPC-3 and Capan-2 cells was also inhibited by LRG1 knockdown, which caused impaired tube formation of co-cultured HUVECs. LRG1 overexpression enhanced the viability, migration, and invasion of BxPC-3 and Capan-2 cells, also causing elevated tube formation of HUVECs and IL-1β and IL-18 synthesis in co-cultures of HUVECs and BxPC-3 or Capan-2 cells. Silencing of VEGF receptor (VEGFR) abrogated the enhanced tube formation and IL-1β and IL-18 synthesis in HUVECs co-cultured with BxPC-3 or Capan-2 cells overexpressing LRG1.

CONCLUSIONS

In conclusion, LRG1, which is highly expressed in pancreatic cancer cells, promotes inflammatory factor synthesis and the angiogenesis of HUVECs though activating the VEGFR signaling pathway.

Anlotinib is effective in the treatment of advanced pancreatic cancer: a case report

Effective treatments are urgently needed for patients with advanced pancreatic cancer. Anlotinib is a novel small-molecule multitarget tyrosine kinase inhibitor with broad inhibitory effects on tumor growth and angiogenesis. Here, we present an advanced pancreatic cancer patient, who respond to anlotinib targeted therapy after the failure of multiline chemotherapy and apatinib targeted therapy. Anlotinib was given orally at a dose of 10 mg once daily (2 weeks on/1 week off), and progression-free survival was 5.6 months. The adverse reaction of anlotinib was elevated aminotransferase and fatigue, but it was tolerable and reversible. Our case indicates that anlotinib might be effective in the treatment of advanced pancreatic cancer. This case report may offer a new targeted treatment option for heavily treated advanced pancreatic cancer.

Validation of Serum Biomarkers That Complement CA19-9 in Detecting Early Pancreatic Cancer Using Electrochemiluminescent-Based Multiplex Immunoassays

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy; its early detection is critical for improving prognosis. Electrochemiluminescent-based multiplex immunoassays were developed with high analytical performance. All proteins were analyzed in sera of patients diagnosed with PDAC (n = 138), benign pancreatic conditions (111), and healthy controls (70). The clinical performance of these markers was evaluated individually or in combination for their complementarity to CA19-9 in detecting early PDAC. Logistic regression modeling including sex and age as cofactors identified a two-marker panel of CA19-9 and CA-125 that significantly improved the performance of CA19-9 alone in discriminating PDAC (AUC: 0.857 vs. 0.766), as well as early stage PDAC (0.805 vs. 0.702) from intraductal papillary mucinous neoplasm (IPMN). At a fixed specificity of 80%, the panel significantly improved sensitivities (78% vs. 41% or 72% vs. 59%). A two-marker panel of HE4 and CEA significantly outperformed CA19-9 in separating IPMN from chronic pancreatitis (0.841 vs. 0.501). The biomarker panels evaluated by assays demonstrated potential complementarity to CA19-9 in detecting early PDAC, warranting additional clinical validation to determine their role in the early detection of pancreatic cancer.

Targeting Growth Factor Signaling Pathways in Pancreatic Cancer: Towards Inhibiting Chemoresistance

Pancreatic cancer is one of the most deadly cancers, ranking amongst the top leading cause of cancer related deaths in developed countries. Features such as dense stroma microenvironment, abnormal signaling pathways, and genetic heterogeneity of the tumors contribute to its chemoresistant characteristics. Amongst these features, growth factors have been observed to play crucial roles in cancer cell survival, progression, and chemoresistance. Here we review the role of the individual growth factors in pancreatic cancer chemoresistance. Importantly, the interplay between the tumor microenvironment and chemoresistance is explored in the context of pivotal role played by growth factors. We further describe current and future potential therapeutic targeting of these factors.

Anti-angiogenic Agents: A Review on Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) Inhibitors

Tumor growth inhibition can be achieved by inhibiting angiogenesis, which has been a field of great concern in recent years. Important targets to inhibit angiogenesis include vascular endothelial growth factor receptor (VEGFR) and its homologous tyrosine kinase receptor. Anti-angiogenic therapy based on inhibition of VEGFR-2 is an effective clinical treatment strategy. The research progress of VEGFR-2 inhibitors is reviewed in this paper from the aspects of drug development and chemical synthesis.

Foretinib induces G2/M cell cycle arrest, apoptosis, and invasion in human glioblastoma cells through c-MET inhibition

PURPOSE

Glioblastoma multiforme (GBM) is one of the most aggressive human cancers. The c-MET receptor tyrosine kinase (RTK) which is frequently deregulated in GBM is considered as a promising target for GBM treatment. The c-MET plays a key role in cell proliferation, cell cycle progression, invasion, angiogenesis, and metastasis. Here, we investigated the anti-tumour activity of foretinib, a c-MET inhibitor, on three human GBM cells (T98G, U87MG and U251).

METHODS

Anti-proliferative effect of foretinib was determined using MTT, crystal violet staining, and clonogenic assays. PI and Annexin V/PI staining flow cytometry were used to evaluate the effects of foretinib on cell cycle and apoptosis, respectively. Scratch assay, qRT-PCR, western blot, and zymography analyses were applied to elucidate the molecular mechanisms underlying the anti-tumour activity of foretinib.

RESULTS

Foretinib treatment reduced phosphorylation of c-MET on T98G and U251 cells, but not in U87MG cells. The highest inhibitory effect was observed in T98G cells (IC₅₀ = 4.66 ± 0.29 µM) and the lowest one in U87MG cells (IC₅₀ = 29.99 ± 1.31 µM). The results showed that foretinib inhibited the proliferation of GBM cells through a G2/M cell cycle arrest and mitochondrial-mediated apoptosis in association with alternation in expression of the related genes and protein-regulated G2/M phase and apoptosis. Foretinib diminished GBM cell invasion through downregulation of the proteolytic cascade of MMP2, uPA and uPAR and epithelial-mesenchymal transition (EMT)-related genes. A different GBM cell sensitivity pattern was noticeable in all experiments which demonstrated T98G as a sensitive and U87MG as a resistant phenotype to foretinib treatment.

CONCLUSION

The results indicated that foretinib might have the therapeutic potential against human GBM which deserve further investigation.

Design, molecular docking, in vitro, and in vivo studies of new quinazolin-4(3H)-ones as VEGFR-2 inhibitors with potential activity against hepatocellular carcinoma

A series of new VEGFR-2 inhibitors were designed, synthesized and evaluated for their anti-proliferative activities against hepatocellular carcinoma (HepG-2 cell line). Compound 29_b (IC₅₀ = 4.33 ± 0.2 µg/ml) was found to be the most potent derivative as it has showed to be more active than doxorubicin (IC₅₀ = 4.50 ± 0.2 µg/ml) and 78% of sorafenib activity (IC₅₀ = 3.40 ± 0.25 µg/ml). The inhibitory profiles against VEGFR-2 were also assessed for the most promising candidates (16_b, 20_c, 22_b, 24_a, 24_b, 28_c, 28_e, 29_a, 29_b and 29_c). Compounds 29_b, 29_c and 29_a exhibited potent inhibitory activities towards VEGFR-2 at IC₅₀ values of 3.1 ± 0.04, 3.4 ± 0.05 and 3.7 ± 0.06 µM, respectively, comparing sorafenib (IC₅₀ = 2.4 ± 0.05 µM). Furthermorer, compound 29_b induced apoptosis and arrested the cell cycle growth at G2/M phase. Additionally, in vivo antitumor experiments revealed that compounds 29_b and 29_c have significant tumor growth inhibition. The test of immuno-histochemical expression of activated caspase-3 revealed that there is a time-dependent increase in cleaved caspase-3 protein expression upon exposure of HepG-2 cells to compound 29_b. Moreover, the fibroblastic proliferative index test revealed that compound 29_b could attenuate liver fibrosis. Docking studies also supported the results concluded from the biological screening via prediction of the possible binding interactions of the target compounds with VEGFR-2 active sites using the crystal structure of VEGFR-2 downloaded from the Protein Data Bank, (PDB ID: 2OH4) using Discovery Studio 2.5 software. Further structural optimization of the most active candidates may serve as a useful strategy for getting new lead compounds in search for powerful and selective antineoplastic agents.

Kinome Array Profiling of Patient-Derived Pancreatic Ductal Adenocarcinoma Identifies Differentially Active Protein Tyrosine Kinases

Pancreatic cancer remains one of the most difficult malignancies to treat. Minimal improvements in patient outcomes and persistently abysmal patient survival rates underscore the great need for new treatment strategies. Currently, there is intense interest in therapeutic strategies that target tyrosine protein kinases. Here, we employed kinome arrays and bioinformatic pipelines capable of identifying differentially active protein tyrosine kinases in different patient-derived pancreatic ductal adenocarcinoma (PDAC) cell lines and wild-type pancreatic tissue to investigate the unique kinomic networks of PDAC samples and posit novel target kinases for pancreatic cancer therapy. Consistent with previously described reports, the resultant peptide-based kinome array profiles identified increased protein tyrosine kinase activity in pancreatic cancer for the following kinases: epidermal growth factor receptor (EGFR), fms related receptor tyrosine kinase 4/vascular endothelial growth factor receptor 3 (FLT4/VEGFR-3), insulin receptor (INSR), ephrin receptor A2 (EPHA2), platelet derived growth factor receptor alpha (PDGFRA), SRC proto-oncogene kinase (SRC), and tyrosine kinase non receptor 2 (TNK2). Furthermore, this study identified increased activity for protein tyrosine kinases with limited prior evidence of differential activity in pancreatic cancer. These protein tyrosine kinases include B lymphoid kinase (BLK), Fyn-related kinase (FRK), Lck/Yes-related novel kinase (LYN), FYN proto-oncogene kinase (FYN), lymphocyte cell-specific kinase (LCK), tec protein kinase (TEC), hemopoietic cell kinase (HCK), ABL proto-oncogene 2 kinase (ABL2), discoidin domain receptor 1 kinase (DDR1), and ephrin receptor A8 kinase (EPHA8). Together, these results support the utility of peptide array kinomic analyses in the generation of potential candidate kinases for future pancreatic cancer therapeutic development.

Targeting TAM to Tame Pancreatic Cancer

Pancreatic cancer is expected to become the second leading cause of cancer-related death within the next few years. Current therapeutic strategies have limited effectiveness and therefore there is an urgency to develop novel effective therapies. The receptor tyrosine kinase subfamily TAM (Tyro3, Axl, MerTK) is directly implicated in the pathogenesis of the metastatic, chemoresistant, and immunosuppressive phenotype in pancreatic cancer. TAM inhibitors are promising investigational therapies for pancreatic cancer due to their potential to target multiple aspects of pancreatic cancer biology. Specifically, recent mechanistic investigations and therapeutic combinations in the preclinical setting suggest that TAM inhibition with chemotherapy, targeted therapy, and immunotherapy should be evaluated clinically.

Novel Nargenicin A1 Analog Inhibits Angiogenesis by Downregulating the Endothelial VEGF/VEGFR2 Signaling and Tumoral HIF-1α/VEGF Pathway

Targeting angiogenesis is an attractive strategy for the treatment of angiogenesis-related diseases, including cancer. We previously identified 23-demethyl 8,13-deoxynargenicin (compound 9) as a novel nargenicin A1 analog with potential anticancer activity. In this study, we investigated the antiangiogenic activity and mode of action of compound 9. This compound was found to effectively inhibit in vitro angiogenic characteristics, including the proliferation, invasion, capillary tube formation, and adhesion of human umbilical vein endothelial cells (HUVECs) stimulated by vascular endothelial growth factor (VEGF). Furthermore, compound 9 suppressed the neovascularization of the chorioallantoic membrane of growing chick embryos in vivo. Notably, the antiangiogenic properties of compound 9 were related to the downregulation of VEGF/VEGFR2-mediated downstream signaling pathways, as well as matrix metalloproteinase (MMP)-2 and MMP-9 expression in HUVECs. In addition, compound 9 was found to decrease the in vitro AGS gastric cancer cell-induced angiogenesis of HUVECs by blocking hypoxia-inducible factor-1α (HIF-1α) and VEGF expression in AGS cells. Collectively, our findings demonstrate for the first time that compound 9 is a promising antiangiogenic agent targeting both VEGF/VEGFR2 signaling in ECs and HIF-1α/VEGF pathway in tumor cells.

UPLC-MS/MS assay for quantification of an inhibitor of kinases (Foretinib) in plasma: Application to a pharmacokinetic study in rats

Foretinib, an oral multikinase inhibitor, is known to have anti-tumor effects against cancers. The doses and the levels of foretinib vary based on the type of cancer to be treated. An accurate and precise method is required to determine the level of foretinib and its pharmacokinetics. Here, we developed such a method, which was validated based on the guidelines of the FDA and EMA. Foretinib and ibrutinib (the internal standard (IS)) were extracted using tert-butyl methyl ether. Foretinib and IS were eluted in approximately 1.2 min. Thus, a linear, fast, accurate, and precise method was developed. The calibration curve was linear (r2 ˃ 0.997) in the range of 0.5-400.0 ng/mL and the lowest limit of quantitation was 0.5 ng/mL. The average recovery, accuracy, and precision were 87.9%, 88.7%, and ≤7.8%, respectively. The analyte was deemed stable using various stability tests. The validated assay was then fruitfully applied to a pharmacokinetics study in rats, which revealed that foretinib was absorbed and the maximum concentration achieved at 4.0 h after the administration of a single dose of foretinib.

Synthesis and biological evaluation of novel (E)-N'-benzylidene hydrazides as novel c-Met inhibitors through fragment based virtual screening

C-Met plays a crucial role in the development and progression of neoplastic disease. Type II c-Met inhibitors recognise the inactive DFG-out conformation of the kinase, result in better anti-tumour effects due to synergistic effect against the other kinases. According to our previous works, an (E)-N'-benzylidene group was selected as the initial fragment. Two series of (E)-N'-benzylidene hydrazides were designed by fragment growth method. The inhibitory activities were in vitro investigated against c-Met and VEGFR-2. Compound 10b exhibited the most potent inhibitory activity against the c-Met inhibitor (IC₅₀ = 0.37 nM). Compound 11b exhibited multi-target c-Met kinase inhibitory activity as a potential type II c-Met inhibitor (IC₅₀ = 3.41 nM against c-Met; 25.34 nM against VEGFR-2). The two compounds also demonstrate the feasibility of fragment-based virtual screening method for drug discovery.

The contribution of dietary and plasma folate and cobalamin to levels of angiopoietin-1, angiopoietin-2 and Tie-2 receptors depend on vascular endothelial growth factor status of primary breast cancer patients

The aim of this study was to determine the association of dietary folate and cobalamin with plasma levels of Angiopoietins (ANG), vascular endothelial growth factor-C (VEGF-C) and tyrosine kinase receptor-2 (Tie-2) of primary breast cancer patients. Women (n = 177), aged 30 to 75 years diagnosed with breast cancer were recruited from an ongoing case series study. Dietary intake of nutrients was estimated by using a validated food frequency questionnaire. Enzyme-linked immunosorbent assay was applied to measure biomarkers. MCF-7 cell cultures were supplemented with folic acid (0–40 μM) for 24 h to measure cell viability and fold change of expression by the real-time reverse transcriptase-polymerase chain reaction. Structural equation modeling was applied to analyze the structural relationships between the measured variables of nutrients and Angiopoietins. Dietary intake of folate and cobalamin showed a significant inverse correlation with plasma ANG-1 and ANG-2 (P < 0.05), particularly in subjects with estrogen-receptor positive tumors or low plasma VEGF-C. Plasma folate was positively associated with the ratio of ANG-1/ANG-2 (P < 0.05). Residual intake levels of total cobalamin were inversely associated with plasma ANG-1 when plasma stratum of VEGF-C was high (P < 0.05). Structural equation modeling identified a significant inverse contribution of folate profiles on the latent variable of Angiopoietins (coefficient β = −0.99, P < 0.05). Folic acid treatment resulted in dose-dependent down-regulations on ANGPT1 and ANGPT1/ANGPT2 ratio but VEGF and ANGPT2/VEGF were upregulated at folic acid >20 μM. Studying the contributing role of dietary folate to pro-angiogenic biomarkers in breast cancer patients can infer the preventive role of folate in the ANGs/VEGF-C-dependent cascade of tumor metastasis. By contrast, high concentrations of folic acid in vitro supported VEGF-C-dependent ANGPT2 overexpression might potentiate micro-lymphatic vessel development to support malignant cell dissemination.

Targeted-nanoliposomal combretastatin A4 (CA-4) as an efficient antivascular candidate in the metastatic cancer treatment

A number of antiangiogenic drugs have been approved by the Food and Drug Administration which are used in cancer therapy, and variety of other agents in several stages of clinical development or in preclinical assessment. Among these, combretastatin A4 (CA-4) is an under-researched inhibitor of angiogenesis that shows potential activity in the treatment of advanced tumors with migration capacity. However, its clinical application has been limited due to poor water solubility, low bioavailability, rapid metabolism, and systemic elimination. During the last decade, numerous investigations have been done to overcome these problems by using different CA-4 delivery systems or developing produgs of CA-4 or its structural analogs. Nevertheless, these strategies could not be efficient out of the undesired side effects on normal tissues. Nanoliposomal CA-4 not only benefits from the advantage of using liposomal drugs as opposed to free drugs but also can accumulate in the tumor site via specific targeting ligands, which leads to efficient targeting and enhancement of bioavailability. To the best of our knowledge, we consider an important attempt to understand different factors that might influence the CA-4 loading and release pattern of liposomes and the consequent results in tumor therapy. In this review, we shed light on various studied liposomal CA-4 formulations showing application thereof in cancer treatment.

Safety and Tolerability of c-MET Inhibitors in Cancer

The role of aberrant hepatocyte growth factor receptor (c-MET, also known as tyrosine-protein kinase MET)/hepatocyte growth factor (HGF) signaling in cancer progression and invasion has been extensively studied. c-MET inhibitors have shown promising pre-clinical and early phase clinical trial anti-tumor activity in several tumor types, although results of most phase III trials with these agents have been negative. To date, two small molecule c-MET inhibitors, cabozantinib and crizotinib, have been approved by regulatory authorities for the treatment of selected cancer types, but several novel c-MET inhibitors (either monoclonal antibodies or small molecule c-MET tyrosine kinase inhibitors) and treatment combinations are currently under study in different settings. Here we provide an overview of the mechanism of action and rationale of c-MET inhibition in cancer, the efficacy of approved agents, and novel promising c-MET-inhibitors and novel targeted combination strategies under development in different cancer types, with a focus on the safety profile and tolerability of these compounds.

Inhibition of tumor formation and metastasis by a monoclonal antibody against lymphatic vessel endothelial hyaluronan receptor 1

Although cancer metastasis is associated with poor prognosis, the mechanisms of this event, especially via lymphatic vessels, remain unclear. Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE‐1) is expressed on lymphatic vessel endothelium and is considered to be a specific marker of lymphatic vessels, but it is unknown how LYVE‐1 is involved in the growth and metastasis of cancer cells. We produced rat monoclonal antibodies (mAb) recognizing the extracellular domain of mouse LYVE‐1, and investigated the roles of LYVE‐1 in tumor formation and metastasis. The mAb 38M and 64R were selected from hybridoma clones created by cell fusion between spleen cells of rats immunized with RH7777 rat hepatoma cells expressing green fluorescent protein (GFP)‐fused mouse LYVE‐1 proteins and mouse myeloma cells. Two mAb reacted with RH7777 and HEK293F human embryonic kidney cells expressing GFP‐fused mouse LYVE‐1 proteins in a GFP expression‐dependent manner, and each recognized a distinct epitope. On immunohistology, the 38M mAb specifically stained lymphatic vessels in several mouse tissues. In the wound healing assay, the 64R mAb inhibited cell migration of HEK293F cells expressing LYVE‐1 and mouse lymphatic endothelial cells (LEC), as well as tube formation by LEC. Furthermore, this mAb inhibited primary tumor formation and metastasis to lymph nodes in metastatic MDA‐MB‐231 xenograft models. This shows that LYVE‐1 is involved in primary tumor formation and metastasis, and it may be a promising molecular target for cancer therapy.

Role of the HGF/c-MET tyrosine kinase inhibitors in metastasic melanoma

Metastatic disease in a cancer patient still remains a therapeutic challenge. Metastatic process involves many steps, during which malignant cells succeed to activate cellular pathways promoting survival in hostile environment, engraftment and growth at the distant site from the primary tumor. Melanoma is known for its high propensity to produce metastases even at the early stages of the disease. Here we summarize the most important molecular mechanisms which were associated with the melanoma metastasis. Then, we specifically focus on the signaling pathway mediated by hepatocyte growth factor (HGF) and its receptor c-Met, which play an important role during physiological processes and were been associated with tumorigenesis. We also focus on the effect of the small molecule inhibitors of the tyrosine kinase domain of the c-Met receptor and its effects on properties of melanoma cell. We summarize recent studies, which involved inhibition of the HGF/c-Met signaling in order to decrease melanoma growth and metastatic capacity.

Fucoidan inhibits lymphangiogenesis by downregulating the expression of VEGFR3 and PROX1 in human lymphatic endothelial cells

Lymphangiogenesis is one of the promoters of tumor lymphatic metastasis. Fucoidan which is a fucose-enriched sulfated polysaccharide has effect on various pharmacological activities including anti-metastasis activity. However, the inhibitory effect of fucoidan on lymphangiogenesis remains unclear. Here, fucoidan extracted from U. pinnatifida sporophylls suppressed HLECs proliferation, migration and tube-like structure formation, and had inhibitory effect of tumor-induced lymphangiogenesis in vitro. Additionally, we found that fucoidan had a dose-dependent depressive effect on the expressions of PROX1, vascular endothelial growth factor receptor 3 (VEGFR3), NF-κB, phospho-PI3K and phospho-Akt in HLECs. Moreover, anti-lymphangiogenesis effect of fucoidan was assessed by using mouse tumor model. In summary, fucoidan inhibit tumor lymphangiogenesis and lymphatic metastasis by suppressing the NF-κB/PI3K/Akt signaling pathway through reduced levels of PROX1 and VEGFR3.

ZLM-7 exhibits anti-angiogenic effects via impaired endothelial cell function and blockade of VEGF/VEGFR-2 signaling

Inhibition of angiogenesis is a promising therapeutic strategy against cancer. In this study, we reported that ZLM-7, a combretastain A-4 (CA-4) derivative, exhibited anti-angiogenic activity in vitro and in vivo. In vitro, ZLM-7 induced microtubule cytoskeletal disassembly. It decreased VEGF-induced proliferation, migration, invasion and tube formation in endothelial cells, which are critical steps in angiogenesis. In vivo, ZLM-7 significantly inhibited neovascularization in a chicken chorioallantoic membrane (CAM) model and reduced the microvessel density in tumor tissues of MCF-7 xenograft mouse model. ZLM-7 also displayed comparable antiangiogenic and anti-tumor activities associated with the lead compound CA-4, but exhibited lower toxicity compared with CA-4. The anti-angiogenic effect of ZLM-7 was exerted via blockade of VEGF/VEGFR-2 signaling. ZLM-7 treatment suppressed the expression and secretion of VEGF in endothelial cells and MCF-7 cells under hypoxia. Further, ZLM-7 suppressed the VEGF-induced phosphorylation of VEGFR-2 and its downstream signaling mediators including activated AKT, MEK and ERK in endothelial cells. Overall, these results demonstrate that ZLM-7 exhibits anti-angiogenic activities by impairing endothelial cell function and blocking VEGF/VEGFR-2 signaling, suggesting that ZLM-7 might be a potential angiogenesis inhibitor.

Triple-amiRNA VEGFRs inhibition in pancreatic cancer improves the efficacy of chemotherapy through EMT regulation

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal outcome. Both novel prognostic markers and therapeutic targets are needed to improve the overall outcome of patients. Although single or double VEGFRs have been studied in PDAC, little is known about the role of triple combination of VEGFRs (VEGFR1, 2, and 3) in prognosis and therapy. We determined VEGFRs protein expression in 241 pancreatic tissues by tissue microarray immunohistochemistry (TMA-IHC), and correlated with patients' clinical characteristics and overall survival. Subsequently, we inactivated VEGFRs expression using artificial microRNAs (amiRNAs) in vitro. Triple combination of amiRNAs to VEGFRs reduced cell proliferation, increased apoptosis, and reduced cell migration and invasion in pancreatic cancer cell lines. In the mouse xenograft pancreatic cancer model, triple VEGFRs silencing significantly reduced tumor growth, had synergistic effect with standard chemotherapy, and was associated with inhibition of epithelial mesenchymal transition (EMT). We conclude that triple combination of VEGFRs is a prognostic marker for PDAC, and inhibition of VEGFRs expression via amiRNA represents a novel targeted therapy in PDAC through regulating EMT.

Ockham's razor for the MET-driven invasive growth linking idiopathic pulmonary fibrosis and cancer

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) identifies a specific lung disorder characterized by chronic, progressive fibrosing interstitial pneumonia of unknown etiology, which lacks effective treatment. According to the current pathogenic perspective, the aberrant proliferative events in IPF resemble those occurring during malignant transformation.

MAIN BODY

Receptor tyrosine kinases (RTK) are known to be key players in cancer onset and progression. It has been demonstrated that RTK expression is sometimes also altered and even druggable in IPF. One example of an RTK-the MET proto-oncogene-is a key regulator of invasive growth. This physiological genetic program supports embryonic development and post-natal organ regeneration, as well as cooperating in the evolution of cancer metastasis when aberrantly activated. Growing evidence sustains that MET activation may collaborate in maintaining tissue plasticity and the regenerative potential that characterizes IPF.

CONCLUSION

The present work aims to elucidate-by applying the logic of simplicity-the bio-molecular mechanisms involved in MET activation in IPF. This clarification is crucial to accurately design MET blockade strategies within a fully personalized approach to IPF.

Effects of inhibitors of vascular endothelial growth factor receptor 2 and downstream pathways of receptor tyrosine kinases involving phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin or mitogen-activated protein kinase in canine hemangiosarcoma cell lines

Canine hemangiosarcoma (HSA) is a progressive malignant neoplasm with no current effective treatment. Previous studies showed that receptor tyrosine kinases and molecules within their downstream pathways involving phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (m-TOR) or mitogen-activated protein kinase (MAPK) were overexpressed in canine, human, and murine tumors, including HSA. The present study investigated the effects of inhibitors of these pathways in canine splenic and hepatic HSA cell lines using assays of cell viability and apoptosis. Inhibitors of the MAPK pathway did not affect canine HSA cell viability. However, cell viability was significantly reduced by exposure to inhibitors of vascular endothelial growth factor receptor 2 and the PI3K/Akt/m-TOR pathway; these inhibitors also induced apoptosis in these cell lines. These results suggest that these inhibitors reduce the proliferation of canine HSA cells by inducing apoptosis. Further study of these inhibitors, using xenograft mouse models of canine HSA, are warranted to explore their potential for clinical application.

The anti-angiogenic effect and novel mechanisms of action of Combretastatin A-4

Combretastatin A-4 (CA4) is the lead compound of a relatively new class of vascular disrupting agents that target existing tumor blood vessels. Recent studies showed the CA4 might inhibit angiogenesis. However, the underlying molecular mechanisms by which CA4 exerts its anti-angiogenic effects are not fully understood. In this study, we revealed that CA4 inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration and capillary-like tube formation of human umbilical vascular endothelial cells (HUVECs). In in vivo assay, CA4 suppressed neovascularization in chicken chorioallantoic membrane (CAM) model and decreased the microvessel density in tumor tissues of a breast cancer MCF-7 xenograft mouse model. In addition, CA4 decreased the expression level and secretion of VEGF both in MCF-7 cells and HUVECs under hypoxia, as well as the activation of VEGFR-2 and its downstream signaling mediators following VEGF stimulation in HUVECs. Moreover, VEGF and VEGFR-2 expression in tumor tissues of the mouse xenograft model were down-regulated following CA4 treatment. Taken together, results from the current work provide clear evidence that CA4 functions in endothelial cell system to inhibit angiogenesis, at least in part, by attenuating VEGF/VEGFR-2 signaling pathway.

Discovery of Potent c-MET Inhibitors with New Scaffold Having Different Quinazoline, Pyridine and Tetrahydro-Pyridothienopyrimidine Headgroups

Cellular mesenchymal-epithelial transition factor (c-MET) is closely linked to human malignancies, which makes it an important target for treatment of cancer. In this study, a series of 3-methoxy-N-phenylbenzamide derivatives, N-(3-(tert-butyl)-1-phenyl-1H-pyrazol-5-yl) benzamide derivatives and N¹-(3-fluoro-4-methoxyphenyl)-N³-(4-fluorophenyl) malonamide derivatives were designed and synthesized, some of them were identified as c-MET inhibitors. Among these compounds with new scaffolds having different quinazoline, pyridine and tetrahydro-pyridothienopyrimidine head groups, compound 11c, 11i, 13b, 13h exhibited both potent inhibitory activities against c-MET and high anticancer activity against tested cancer cell lines in vitro. In addition, kinase selectivity assay further demonstrated that both 13b and 13h are potent and selective c-MET inhibitors. Molecular docking supported that they bound well to c-MET and VEGFR2, which demonstrates that they are potential c-MET RTK inhibitors for cancer therapy.

Tumor lymphangiogenesis and new drug development

Traditionally, tumor-associated lymphatic vessels have been regarded as passive by-standers, serving simply as a drainage system for interstitial fluid generated within the tumor. However, with growing evidence that tumors actively induce lymphangiogenesis, and that the number of lymphatic vessels closely correlates with metastasis and clinical outcome in various types of cancer, this picture has changed dramatically in recent years. Tumor-associated lymphatic vessels have now emerged as a valid therapeutic target to control metastatic disease, and the first specific anti-lymphangiogenic drugs have recently entered clinical testing. Furthermore, we are just beginning to understand the whole functional spectrum of tumor-associated lymphatic vessels, which not only concerns transport of fluid and metastatic cells, but also includes the regulation of cancer stemness and specific inhibition of immune responses, opening new venues for therapeutic applications. Therefore, we predict that specific targeting of lymphatic vessels and their function will become an important tool for future cancer treatment.

The progress of angiogenic factors in the development of leukemias

Angiogenic factors have been demonstrated to play important roles in modulating angiogenesis of solid tumors. Recently, accumulating studies extensively indicated that some angiogenic factors widely exist in malignant cells of hematologic malignancy, which regulated the expression of a number of genes that were involved in abnormal proliferation, differentiation and apoptosis of these cells. With deep research of angiogenic factors, its expression, function and regulatory mechanism were gradually elucidated, and some of them were related to the development and prognosis of leukemia, or provide more possible strategies for treatment of patients with leukemia. Herein, we summarize the progress in study of some important angiogenic factors and hematological malignancies.

The effect of NFATc1 on vascular generation and the possible underlying mechanism in epithelial ovarian carcinoma

We investigated the effect of nuclear factor of activated T cells c1 (NFATc1) on the growth and vascular generation of human ovarian carcinoma SKOV3 cell-transplanted tumors in nude mice and explored the possible underlying mechanism. NFATc1 siRNA was transfected into the SKOV3 cells, which were then subjected to immunofluorescence tests and real-time reverse transcription polymerase chain reaction (RT-PCR) to determine the transfection-induced inhibition rate. The tumor volumes in the nude mice in all groups were measured to determine the in vivo antitumor effect of NFATc1 siRNA. Immunohistochemical (IHC) methods were employed to detect NFATc1 expression in tumor tissue, combined with cytokeratin (CK) staining to label the epithelial origin of the tumor tissue. CD34 and podoplanin were used as markers for labeling microvessels and microlymphatic vessels, respectively. The densities of microvessels and microlymphatic vessels in each group were calculated and statistically analyzed. RT-PCR and western blotting were performed to detect the protein and mRNA expression levels of NFATc1, the ELR+ CXC chemokine interleukin (IL)-8, fibroblast growth factor-2 (FGF-2), and platelet-derived growth factor BB (PDGF BB) in xenografted tumor tissue in all groups. NFATc1 was highly expressed in tumor tissue in the control groups. The intervention group exhibited a tumor growth inhibition rate of 57.08% and presented a lower tumor weight and volume compared with the two control groups. In the control groups, the microvessel densities were 12.00 ± 1.65 and 11.47 ± 0.32, respectively, and the microlymphatic vessel densities were 10.03 ± 0.96 and 9.95 ± 1.12; these values were significantly higher than in the intervention group. RT-PCR and western blot shows that NFATc1 siRNA could markedly suppress the expression of IL-8, FGF-2 and PDGF BB at the mRNA and the protein level. In conclusion, it was shown that NFATc1 siRNA significantly suppresses the growth and vascular generation of SKOV3 human ovarian carcinoma cell-transplanted tumors subcutaneously xenografted into nude mice. The downregulation of the expression of IL-8, FGF-2 and PDGF BB may be one of the mechanisms underlying the above inhibitory effects.

Molecular targets for the treatment of pancreatic cancer: Clinical and experimental studies

Pancreatic cancer is the fourth most common cause of cancer deaths worldwide. Although recent therapeutic developments for patients with pancreatic cancer have provided survival benefits, the outcomes for patients with pancreatic cancer remain unsatisfactory. Molecularly targeted cancer therapy has advanced in the past decade with the use of a number of pathways as candidates of therapeutic targets. This review summarizes the molecular features of this refractory disease while focusing on the recent clinical and experimental findings on pancreatic cancer. It also discusses the data supporting current standard clinical outcomes, and offers conclusions that may improve the management of pancreatic cancer in the future.

The lymphatic system and pancreatic cancer

This review summarizes current knowledge of the biology, pathology and clinical understanding of lymphatic invasion and metastasis in pancreatic cancer. We discuss the clinical and biological consequences of lymphatic invasion and metastasis, including paraneoplastic effects on immune responses and consider the possible benefit of therapies to treat tumors that are localized to lymphatics. A review of current techniques and methods to study interactions between tumors and lymphatics is presented.

Effects of CASP5 gene overexpression on angiogenesis of HMEC-1 cells

OBJECTIVES

The efficacy of gene overexpression of CASP5, a caspase family member, in angiogenesis in vitro and its mechanisms were clarified.

METHODS

Human full-length CASP5 gene was delivered into human microvascular endothelial HMEC-1 cells by recombinant lentivirus. The infection was estimated by green fluorescent protein. MTT method was used to analyze the efficacy of gene overexpression in cell proliferation ability, and Matrigel was used to estimate its effects in angiogenesis ability of cells. Meanwhile, Western blot was used to analyze the effects of CASP5 gene overexpression on the expression levels of angpt-1, angpt-2, Tie2 and VEGF-1 in the cells, which were signaling pathway factors related to angiogenesis.

RESULTS

Recombinant lentivirus containing human full-length CASP5 gene was packed and purified successfully, with virus titer of 1×10(8) TU/ml. The recombinant lentivirus was used to infect HMEC-1 cells with MOI of 1, leading to a cell infection rate of 100%. There were no significant effects of CASP5 gene overexpression on both cell proliferation ability and the expression level of angpt-1. Meanwhile, expressions of angpt-2 and VEGF-1 were both enhanced, while Tie2 expression was inhibited. Results indicated that CASP5 gene overexpression promoted angiogenesis of HMEC-1 cells.

CONCLUSION

CASP5 gene overexpression significantly promoted angiogenesis ability of HMEC-1 cells, which was probably achieved by inhibiting angpt-1/Tie2 and promoting VEGF-1 signal pathway.

Non-caveolar caveolin-1 expression in prostate cancer cells promotes lymphangiogenesis

Lymphangiogenesis allows prostate cancer (PCa) lymphatic metastasis, which is associated with poor prognosis and short survival rates. Caveolin-1 (Cav-1) is a membrane protein localized in caveolae, but also exists in non-caveolar, cellular or extracellular forms. Cav-1 is overexpressed in PCa, promotes prostate tumour progression and metastasis. We investigated the effect of caveolar and non-caveolar Cav-1 on PCa lymphangiogenic potential. Cav-1 was down-regulated in PC3 and DU145, and ectopically expressed in LNCaP cells. The effect of PCa cell conditioned media on lymphatic endothelial cell (LEC) viability, chemotaxis, chemokinesis and differentiation was assessed. The effect of Cav-1 on PCa cell expression of lymphangiogenesis-modulators VEGF-A and VEGF-C was assessed using qPCR and ELISA of the conditioned medium. Non-caveolar Cav-1, whether exogenous or endogenous (in LNCaP and PC3 cells, respectively) enhanced LEC proliferation, migration and differentiation. In contrast, caveolar Cav-1 (in DU145 cells) did not significantly affect PCa cell lymphangiogenic potential. The effect of non-caveolar Cav-1 on LECs was mediated by increased expression of VEGF-A as demonstrated by neutralization by anti-VEGF-A antibody. This study unveils for the first time a crucial role for non-caveolar Cav-1 in modulating PCa cell expression of VEGF-A and subsequent LEC proliferation, migration and tube formation.