Targeting c-Met receptor overcomes TRAIL-resistance in brain tumors

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.

Stem cell-based therapy treating glioblastoma multiforme

Glioblastoma (GB) is one of the most malignant types of central nervous system tumours, classified as grade IV by the World Health Organization. Despite the therapeutic advances, the prognosis is ominous, with a median survival of about 12-15 months post diagnosis. Although therapeutic options available can increase the survival, they are ineffective in treating patients with GB. Impairing factors such as the blood-brain barrier, cancer stem cells, and infiltration into brain parenchyma lead to failure of current therapies. Therefore, clinicians need novel/alternative effective strategies to treat GB. Due to their ability to preserve healthy tissues and to provide an effective and long-lasting response, stem cells (SCs) with tropism for tumour cells have attracted considerable attention in the scientific community. As is the case here, SCs can be used to target brain tumour cancer cells, especially high-grade malignant gliomas like GB, by overcoming the resistance and exerting benefits for patients affected with such lethal disease. Herein, we will discuss the research knowledge regarding SC-based therapy for the treatment of GB, focalising our attention on SCs and SC-released extracellular vesicles modified to express/load different antitumour payloads, as well as on SCs exploited as a diagnostic tool. Advantages and unresolved issues of anticancer SC-based therapy will also be considered.

Cell primitive-based biomimetic functional materials for enhanced cancer therapy

Cell primitive-based functional materials that combine the advantages of natural substances and nanotechnology have emerged as attractive therapeutic agents for cancer therapy. Cell primitives are characterized by distinctive biological functions, such as long-term circulation, tumor specific targeting, immune modulation etc. Moreover, synthetic nanomaterials featuring unique physical/chemical properties have been widely used as effective drug delivery vehicles or anticancer agents to treat cancer. The combination of these two kinds of materials will catalyze the generation of innovative biomaterials with multiple functions, high biocompatibility and negligible immunogenicity for precise cancer therapy. In this review, we summarize the most recent advances in the development of cell primitive-based functional materials for cancer therapy. Different cell primitives, including bacteria, phages, cells, cell membranes, and other bioactive substances are introduced with their unique bioactive functions, and strategies in combining with synthetic materials, especially nanoparticulate systems, for the construction of function-enhanced biomaterials are also summarized. Furthermore, foreseeable challenges and future perspectives are also included for the future research direction in this field.

Visualization of Diagnostic and Therapeutic Targets in Glioma With Molecular Imaging

Gliomas, particularly high-grade gliomas including glioblastoma (GBM), represent the most common and malignant types of primary brain cancer in adults, and carry a poor prognosis. GBM has been classified into distinct subgroups over the years based on cellular morphology, clinical characteristics, biomarkers, and neuroimaging findings. Based on these classifications, differences in therapeutic response and patient outcomes have been established. Recently, the identification of complex molecular signatures of GBM has led to the development of diverse targeted therapeutic regimens and translation into multiple clinical trials. Chemical-, peptide-, antibody-, and nanoparticle-based probes have been designed to target specific molecules in gliomas and then be visualized with multimodality molecular imaging (MI) techniques including positron emission tomography (PET), single-photon emission computed tomography (SPECT), near-infrared fluorescence (NIRF), bioluminescence imaging (BLI), and magnetic resonance imaging (MRI). Thus, multiple molecules of interest can now be noninvasively imaged to guide targeted therapies with a potential survival benefit. Here, we review developments in molecular-targeted diagnosis and therapy in glioma, MI of these targets, and MI monitoring of treatment response, with a focus on the biological mechanisms of these advanced molecular probes. MI probes have the potential to noninvasively demonstrate the pathophysiologic features of glioma for diagnostic, treatment, and response assessment considerations for various targeted therapies, including immunotherapy. However, most MI tracers are in preclinical development, with only integrin α_Vβ₃ and isocitrate dehydrogenase (IDH)-mutant MI tracers having been translated to patients. Expanded international collaborations would accelerate translational research in the field of glioma MI.

Mesenchymal epithelial transition factor regulates tumor necrosis factor-related apoptotic induction ligand resistance in hepatocellular carcinoma cells through down-regulation of cyclin B1

Tumor necrosis factor-related apoptotic induction ligand can induce cell apoptosis in various tumor cells. However, many cancer cells are resistant to tumor necrosis factor-related apoptotic induction ligand. Therefore, overcoming the tumor necrosis factor-related apoptotic induction ligand resistance makes it possible for tumor necrosis factor-related apoptotic induction ligand-based anti-cancer therapies. In this study, we took mesenchymal epithelial transition factor as the research target to study its role in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma. Mesenchymal epithelial transition factor gene has been proved to be an effective predictor of recurrence after hepatocellular carcinoma resection. The expression of mesenchymal epithelial transition factor and cyclin B1 were measured in tumor necrosis factor-related apoptotic induction ligand-resistant and non-resistant hepatocellular carcinoma tissues. Cyclin B1-knockdown and cyclin B1-overexpression hepatocellular carcinoma cells were treated with tumor necrosis factor-related apoptotic induction ligand; mesenchymal epithelial transition factor knockout, mesenchymal epithelial transition factor re-introduction and cyclin B1 restored in hepatocellular carcinoma cells treated with tumor necrosis factor-related apoptotic induction ligand were established. And MTT, bromodeoxyuridine, flow cytometry and western blotting were performed to evaluate the effect of mesenchymal epithelial transition factor and cyclin B1 on hepatocellular carcinoma cells treated with tumor necrosis factor-related apoptotic induction ligand. In addition, subcutaneous tumor transplantation in nude mice was conducted to access the effect of mesenchymal epithelial transition factor and cyclin B1 on tumor formation in vivo. In conclusion, cyclin B1 enhanced the cell growth and inhibited apoptosis in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma cells. And mesenchymal epithelial transition factor promoted the cell growth and apoptosis in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma cells by regulating cyclin B1. Therefore, mesenchymal epithelial transition factor regulates the cyclin B1 to regulate tumor necrosis factor-related apoptotic induction ligand resistance in hepatocellular carcinoma cells. Our results suggest a novel molecular mechanism for regulating tumor necrosis factor-related apoptotic induction ligand resistance, which might be helpful to select drug targets in the treatment of liver cancer.

Mammary Tumor Cells with High Metastatic Potential Are Hypersensitive to Macrophage-Derived HGF

Metastasis-associated macrophages (MAM) promote persistent growth of breast cancer cells at the metastatic site and are, thus, an attractive therapeutic target to treat breast cancer metastasis, a leading cause of cancer-related death in women. However, the precise mechanisms behind MAM-mediated metastatic tumor outgrowth have not been fully elucidated. Using mouse models of metastatic breast cancer, we showed that MAMs uniquely expressed hepatocyte growth factor (HGF) in metastatic tumors. We also demonstrated that a selected population of cancer cells with high metastatic potential (cancer cells that can establish metastatic tumors in mice with higher number and incidence than parental cells) had higher expression of HGF receptor, MNNG HOS transforming gene (MET), and were more responsive to HGF released from macrophages compared with the parental cells. Blockade of MET signaling in cancer cells suppressed metastatic tumor expansion, in part, through activation of natural killer cells. Results from this study suggest an approach to prevent life-threatening metastatic tumor formation using blockade of MAM-induced MET signal activation in metastatic cancer cells.

Combination therapy with c-met inhibitor and TRAIL enhances apoptosis in dedifferentiated liposarcoma patient-derived cells

Background

Liposarcoma (LPS) is a tumor derived from adipose tissue, and has the highest incidence among soft tissue sarcomas. Dedifferentiated liposarcoma (DDLPS) is a malignant tumor with poor prognosis. Recurrence and metastasis rates in LPS remain high even after chemotherapy and radiotherapy following complete resection. Therefore, the development of advanced treatment strategies for LPS is required. In the present study, we investigated the effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor on cell viability and apoptosis in LPS and DDLPS cell lines of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor.

Methods

We analyzed cell viability after treatment with TRAIL and a c-Met inhibitor by measuring CCK8 and death receptor 5 (DR5) expression levels via fluorescence activated cell sorting (FACS) in both sarcoma cell lines and DDLPS patient-derived cells (PDCs). Moreover, we validated the effects of TRAIL alone and in combination with c-Met inhibitor on apoptosis in LPS cell lines and DDLPS PDCs via FACS.

Results

Our results revealed that combination treatment with a c-Met inhibitor and human recombinant TRAIL (rhTRAIL) suppressed cell viability and induced cell death in both sarcoma cell lines and DDLPS PDCs, which showed varying sensitivities to rhTRAIL alone. Also, we confirmed that treatment with a c-Met inhibitor upregulated DR5 levels in sarcoma cell lines and DDLPS PDCs. In both TRAIL-susceptible and TRAIL-resistant cells subjected to combination treatment, promotion of apoptosis was dependent on DR5 upregulation.

Conclusion

From these results, our findings validated that DR5 up-regulation caused by combination therapy with a c-Met inhibitor and rhTRAIL enhanced TRAIL sensitization and promoted apoptosis. We propose the use of this approach to overcome TRAIL resistance and serve as a novel treatment strategy for clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5713-2) contains supplementary material, which is available to authorized users.

Stem cell-based therapies for tumors in the brain: are we there yet?

Advances in understanding adult stem cell biology have facilitated the development of novel cell-based therapies for cancer. Recent developments in conventional therapies (eg, tumor resection techniques, chemotherapy strategies, and radiation therapy) for treating both metastatic and primary tumors in the brain, particularly glioblastoma have not resulted in a marked increase in patient survival. Preclinical studies have shown that multiple stem cell types exhibit inherent tropism and migrate to the sites of malignancy. Recent studies have validated the feasibility potential of using engineered stem cells as therapeutic agents to target and eliminate malignant tumor cells in the brain. This review will discuss the recent progress in the therapeutic potential of stem cells for tumors in the brain and also provide perspectives for future preclinical studies and clinical translation.

Mechanism of QHF-cisplatin against hepatocellular carcinoma in a mouse model

AIM: To study the effects of QHF-cisplatin on H₂₂ hepatocellular carcinoma (HCC) and their mechanisms of action.

METHODS: Sixty BALB/c mice were randomly divided into a model group (n = 48) and a normal control group (n = 12). An HCC xenograft tumor was created by injecting H₂₂ cells directly into the liver parenchyma of the mice. The 48 BALB/c mice in the model group were randomly divided into four groups: QHF, DDP (cisplatin), QHF plus DDP, and model control. The inhibitory effects of these drugs on tumor growth were evaluated by calculating the rate of tumor growth inhibition. The mice were examined by observing their general condition, body weight and survival time. Changes in tumor tissue were observed under an optical microscope. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and α-fetoprotein (AFP) levels in serum were measured. Hepatocyte growth factor (HGF), c-mesenchymal-epithelial transition (c-Met) factor, phosphorylated (p)-c-Met, p38, p-p38, extracellular signal-regulated kinase (ERK), p-ERK and vascular endothelial growth factor (VEGF) levels were evaluated in tumor and liver tissues using western blotting.

RESULTS: Compared with the DDP group, a lower incidence of toxic reactions and a higher survival time were observed in the QHF plus DDP group. Tumor weight was significantly lower in the QHF, DDP and QHF plus DDP groups than in the model control group (0.24 ± 0.07, 0.18 ± 0.03 and 0.14 ± 0.01 g vs 0.38 ± 0.05 g, respectively), and the differences were statistically significant (P < 0.01). The rate of tumor growth inhibition in the QHF, DDP and QHF plus DDP groups was 38.7%, 52.6% and 63.5%, respectively. AST, ALT and AFP levels in serum were significantly lower in the QHF, DDP and QHF plus DDP groups compared to the model control group (P < 0.05). Similarly, HGF, p-c-Met, p-p38, p-ERK and VEGF levels in tumor tissue were significantly lower in the QHF, DDP and QHF plus DDP groups (P < 0.05).

CONCLUSION: QHF and DDP have an antiangiogenic effect on H₂₂ HCC in mice. QHF inhibits tumor growth via blocking the HGF/c-Met signaling pathway, inhibiting p38, ERK and VEGF signaling.

c-Met and Other Cell Surface Molecules: Interaction, Activation and Functional Consequences

The c-Met receptor, also known as the HGF receptor, is one of the most studied tyrosine kinase receptors, yet its biological functions and activation mechanisms are still not fully understood. c-Met has been implicated in embryonic development and organogenesis, in tissue remodelling homeostasis and repair and in cancer metastasis. These functions are indicative of the many cellular processes in which the receptor plays a role, including cell motility, scattering, survival and proliferation. In the context of malignancy, sustained activation of c-Met leads to a signalling cascade involving a multitude of kinases that initiate an invasive and metastatic program. Many proteins can affect the activation of c-Met, including a variety of other cell surface and membrane-spanning molecules or receptors. Some cell surface molecules share structural homology with the c-Met extracellular domain and can activate c-Met via clustering through this domain (e.g., plexins), whereas other receptor tyrosine kinases can enhance c-Met activation and signalling through intracellular signalling cascades (e.g., EGFR). In this review, we provide an overview of c-Met interactions and crosstalk with partner molecules and the functional consequences of these interactions on c-Met activation and downstream signalling, c-Met intracellular localization/recycling and c-Met degradation.

Stem cell-based therapies for cancer treatment: separating hope from hype

Stem cell-based therapies are emerging as a promising strategy to tackle cancer. Multiple stem cell types have been shown to exhibit inherent tropism towards tumours. Moreover, when engineered to express therapeutic agents, these pathotropic delivery vehicles can effectively target sites of malignancy. This perspective considers the current status of stem cell-based treatments for cancer and provides a rationale for translating the most promising preclinical studies into the clinic.