Inferring the Effects of Honokiol on the Notch Signaling Pathway in SW480 Colon Cancer Cells

Honokiol combined with curcumin sensitizes multidrug-resistant human lung adenocarcinoma A549/DDP cells to cisplatin

The aim of the present study was to discuss the effects and underlying mechanisms of honokiol (HNK) and/or curcumin (CUR) in sensitization of multidrug-resistant human lung adenocarcinoma A549/DDP cells to cisplatin (DDP). An MTS assay was performed to detect the cytotoxicity of HNK, CUR and DDP in A549 and A549/DDP cells and compare their sensitivity. The A549/DDP cells were then divided into 8 groups: Control, HNK, CUR, DDP, HNK + CUR, HNK + DDP, CUR + DDP and HNK + CUR + DDP. Cell proliferation was measured by MTS assay and colony formation assay, cell apoptosis was detected by flow cytometry, cell invasion was evaluated by Transwell assay and cell migration was determined by a wound healing assay. In order to investigate the possible mechanisms, P-glycoprotein (P-gp) protein expression was measured by western blotting and immunofluorescence assays. The mRNA expression levels of AKT, Erk1/2, cyclin-dependent kinase inhibitor 1 (P21), caspase 3, cleaved caspase 3, caspase 9, cleaved caspase 9, poly (ADP-ribose) polymerase (PARP), cleaved PARP, matrix metalloproteinase (MMP)-2 and MMP-9 were examined by reverse transcription-quantitative (RT-q) PCR assay, and the protein expression levels of phosphorylated (p)-AKT, p-Erk1/2, P21, caspase 3, cleaved caspase 3, caspase 9, cleaved caspase 9, PARP, cleaved PARP, MMP-2 and MMP-9 proteins expression by western blot assay. The MTS assay demonstrated that HNK (5 µg/ml), CUR (10 µg/ml) and DDP (5 µg/ml) had no obvious toxicity to A549/DDP cells, and HNK, CUR and DDP were more sensitive in A549 cells compared with A549/DDP cells. The optimal concentrations of HNK (5 µg/ml), CUR (10 µg/ml) and DDP (5 µg/ml) were chosen to carry out the further experiments. Compared with the control group, no significant change was observed in cell proliferation, apoptosis, migration, invasion and related mRNA and protein expression in HNK, CUR, DDP and HNK + CUR groups. The cell proliferation rate in the HNK + DDP and CUR + DDP groups was significantly suppressed with cell apoptosis significantly increased, respectively. The invasion cell number and wound healing rate of HNK + DDP and CUR + DDP groups were significantly depressed compared with the control group, respectively. Immunofluorescence demonstrated that the nuclear volume of P-gp in HNK + DDP and CUR + DDP groups were significantly downregulated compared with the control group, respectively. The RT-qPCR assay demonstrated that the AKT, Erk1/2 and P21 mRNA expression levels were significantly decreased and cleaved caspase 3, cleaved caspase 9 and cleaved PARP were increased in HNK + DDP and CUR + DDP groups compared with the control group. The western blotting results were consistent with the RT-qPCR results. NK + CUR + DDP had improved effects on A549/DDP compared with HNK + DDP or CUR + DDP group, respectively. HNK and/or CUR could improve the sensitivity of DDP to A549/DDP cell by the regulation of P-gp, inducing apoptosis, and inhibiting migration and invasion via AKT/ERK signal pathway in an in vitro study.

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

Simple Summary

The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer.

Abstract

Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations.

Induction of STK11-dependent cytoprotective autophagy in breast cancer cells upon honokiol treatment

Cancer cells hijack autophagy pathway to evade anti-cancer therapeutics. Many molecular signaling pathways associated with drug-resistance converge on autophagy induction. Honokiol (HNK), a natural phenolic compound purified from Magnolia grandiflora, has recently been shown to impede breast tumorigenesis and, in the present study, we investigated whether breast cancer cells evoke autophagy to modulate therapeutic efficacy and functional networks of HNK. Indeed, breast cancer cells exhibit increased autophagosomes-accumulation, MAP1LC3B-II/LC3B-II-conversion, expression of ATG proteins as well as elevated fusion of autophagosomes and lysosomes upon HNK treatment. Breast cancer cells treated with HNK demonstrate significant growth inhibition and apoptotic induction, and these biological processes are blunted by macroautophagy/autophagy. Consequently, inhibiting autophagosome formation, abrogating autophagosome-lysosome fusion or genetic-knockout of BECN1 and ATG7 effectively increase HNK-mediated apoptotic induction and growth inhibition. Next, we explored the functional impact of tumor suppressor STK11 in autophagy induction in HNK-treated cells. STK11-silencing abrogates LC3B-II-conversion, and blocks autophagosome/lysosome fusion and lysosomal activity as illustrated by LC3B-Rab7 co-staining and DQ-BSA assay. Our results exemplify the cytoprotective nature of autophagy invoked in HNK-treated breast cancer cells and put forth the notion that a combined strategy of autophagy inhibition with HNK would be more effective. Indeed, HNK and chloroquine (CQ) show synergistic inhibition of breast cancer cells and HNK-CQ combination treatment effectively inhibits breast tumorigenesis and metastatic progression. Tumor-dissociated cells from HNK-CQ treated tumors exhibit abrogated invasion and migration potential. Together, these results implicate that breast cancer cells undergo cytoprotective autophagy to circumvent HNK and a combined treatment with HNK and CQ can be a promising therapeutic strategy for breast cancer.

Honokiol Suppression of Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Gastric Cancer Cell Biological Activity and Its Mechanism

BACKGROUND The purpose of our study was to determine the effects and mechanisms of honokiol on human epidermal growth factor receptor 2 (HER2)-positive gastric cancer cells by in vitro study. MATERIAL AND METHODS We measured HER2 expression in different gastric cancer cell lines by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) assay. Cell proliferation, apoptosis, and cell cycle were evaluated by cell-counting kit 8 and flow cytometry assays. The invading cell numbers and wound-healing rates were measured by transwell and wound-healing assays. Phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), P21, and matrix metalloproteinase (MMP)-9 proteins and messenger ribonucleic acid (mRNA) expression were measured by WB and RT-qPCR assay. HER2 protein expression was evaluated by cellular immunofluorescence. RESULTS Honokiol suppressed cell proliferation via increasing cell apoptosis, invasion, and migration with dose dependence. By WB and RT-qPCR assays, compared with the control group, PI3K, AKT, P21, and MMP-9 proteins and mRNA expression were significantly different (P<0.05). By cellular immunofluorescence, HER2 protein expression was significantly depressed in honokiol-treated groups compared with control groups (P<0.05). CONCLUSIONS Honokiol has suppressive effects on HER2-positive gastric cancer cell biological activities via regulation of HER2/PI3K/AKT pathways in vitro.

Honokiol: A Review of Its Anticancer Potential and Mechanisms

Cancer is characterised by uncontrolled cell division and abnormal cell growth, which is largely caused by a variety of gene mutations. There are continuous efforts being made to develop effective cancer treatments as resistance to current anticancer drugs has been on the rise. Natural products represent a promising source in the search for anticancer treatments as they possess unique chemical structures and combinations of compounds that may be effective against cancer with a minimal toxicity profile or few side effects compared to standard anticancer therapy. Extensive research on natural products has shown that bioactive natural compounds target multiple cellular processes and pathways involved in cancer progression. In this review, we discuss honokiol, a plant bioactive compound that originates mainly from the Magnolia species. Various studies have proven that honokiol exerts broad-range anticancer activity in vitro and in vivo by regulating numerous signalling pathways. These include induction of G0/G1 and G2/M cell cycle arrest (via the regulation of cyclin-dependent kinase (CDK) and cyclin proteins), epithelial-mesenchymal transition inhibition via the downregulation of mesenchymal markers and upregulation of epithelial markers. Additionally, honokiol possesses the capability to supress cell migration and invasion via the downregulation of several matrix-metalloproteinases (activation of 5' AMP-activated protein kinase (AMPK) and KISS1/KISS1R signalling), inhibiting cell migration, invasion, and metastasis, as well as inducing anti-angiogenesis activity (via the down-regulation of vascular endothelial growth factor (VEGFR) and vascular endothelial growth factor (VEGF)). Combining these studies provides significant insights for the potential of honokiol to be a promising candidate natural compound for chemoprevention and treatment.

Predicting neuroblastoma using developmental signals and a logic-based model

Genomic information from human patient samples of pediatric neuroblastoma cancers and known outcomes have led to specific gene lists put forward as high risk for disease progression. However, the reliance on gene expression correlations rather than mechanistic insight has shown limited potential and suggests a critical need for molecular network models that better predict neuroblastoma progression. In this study, we construct and simulate a molecular network of developmental genes and downstream signals in a 6-gene input logic model that predicts a favorable/unfavorable outcome based on the outcome of the four cell states including cell differentiation, proliferation, apoptosis, and angiogenesis. We simulate the mis-expression of the tyrosine receptor kinases, trkA and trkB, two prognostic indicators of neuroblastoma, and find differences in the number and probability distribution of steady state outcomes. We validate the mechanistic model assumptions using RNAseq of the SHSY5Y human neuroblastoma cell line to define the input states and confirm the predicted outcome with antibody staining. Lastly, we apply input gene signatures from 77 published human patient samples and show that our model makes more accurate disease outcome predictions for early stage disease than any current neuroblastoma gene list. These findings highlight the predictive strength of a logic-based model based on developmental genes and offer a better understanding of the molecular network interactions during neuroblastoma disease progression.

Inferring Intracellular Signal Transduction Circuitry from Molecular Perturbation Experiments

The development of network inference methodologies that accurately predict connectivity in dysregulated pathways may enable the rational selection of patient therapies. Accurately inferring an intracellular network from data remains a very challenging problem in molecular systems biology. Living cells integrate extremely robust circuits that exhibit significant heterogeneity, but still respond to external stimuli in predictable ways. This phenomenon allows us to introduce a network inference methodology that integrates measurements of protein activation from perturbation experiments. The methodology relies on logic-based networks to provide a predictive approximation of the transfer of signals in a network. The approach presented was validated in silico with a set of test networks and applied to investigate the epidermal growth factor receptor signaling of a breast epithelial cell line, MFC10A. In our analysis, we predict the potential signaling circuitry most likely responsible for the experimental readouts of several proteins in the mitogen-activated protein kinase and phosphatidylinositol-3 kinase pathways. The approach can also be used to identify additional necessary perturbation experiments to distinguish between a set of possible candidate networks.

Long-term stabilization of stage 4 colon cancer using sodium dichloroacetate therapy

Oral dichloroacetate sodium (DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer cells. Response to therapy in human studies is measured by standard RECIST definitions, which define “response” by the degree of tumour reduction, or tumour disappearance on imaging. However, Blackburn et al have demonstrated that DCA can also act as a cytostatic agent in vitro and in vivo, without causing apoptosis (programmed cell death). A case is presented in which oral DCA therapy resulted in tumour stabilization of stage 4 colon cancer in a 57 years old female for a period of nearly 4 years, with no serious toxicity. Since the natural history of stage 4 colon cancer consists of steady progression leading to disability and death, this case highlights a novel use of DCA as a cytostatic agent with a potential to maintain long-term stability of advanced-stage cancer.

Advances and perspectives of colorectal cancer stem cell vaccine

Colorectal cancer is essentially an environmental and genetic disease featured by uncontrolled cell growth and the capability to invade other parts of the body by forming metastases, which inconvertibly cause great damage to tissues and organs. It has become one of the leading causes of cancer-related mortality in the developed countries such as United States, and approximately 1.2 million new cases are yearly diagnosed worldwide, with the death rate of more than 600,000 annually and incidence rates are increasing in most developing countries. Apart from the generally accepted theory that pathogenesis of colorectal cancer consists of genetic mutation of a certain target cell and diversifications in tumor microenvironment, the colorectal cancer stem cells (CCSCs) theory makes a different explanation, stating that among millions of colon cancer cells there is a specific and scanty cellular population which possess the capability of self-renewal, differentiation and strong oncogenicity, and is tightly responsible for drug resistance and tumor metastasis. Based on these characteristics, CCSCs are becoming a novel target cells both in the clinical and the basic studies, especially the study of CCSCs vaccines due to induced efficient immune response against CCSCs. This review provides an overview of CCSCs and preparation technics and targeting factors related to CCSCs vaccines in detail.