Honokiol inhibits HepG2 migration via down-regulation of IQGAP1 expression discovered by a quantitative pharmaceutical proteomic analysis

Honokiol: A naturally occurring lignan with pleiotropic bioactivities

Honokiol is the dominant biphenolic compound isolated from the Magnolia tree, and has long been considered as the active constituent of the traditional Chinese herb, 'Houpo', which is widely used to treat symptoms due to 'stagnation of qi'. Pharmacological studies have shown that honokiol possesses a wide range of bioactivities without obvious toxicity. Honokiol protects the liver, kidneys, nervous system, and cardiovascular system through reducing oxidative stress and relieving inflammation. Moreover, honokiol shows anti-diabetic property through enhancing insulin sensitivity, and anti-obese property through promoting browning of adipocytes. In vivo and in vitro studies indicated that honokiol functions as an anti-cancer agent through multiple mechanisms: inhibiting angiogenesis, promoting cell apoptosis, and regulating cell cycle. A variety of therapeutic effects of honokiol may be associated with its physiochemical properties, which make honokiol readily cross the blood brain barrier and the blood-cerebrospinal fluid barrier, with high bioavailability. In the future, more clinical researches on honokiol are needed to fully authenticate its therapeutic values.

SAE1 promotes human glioma progression through activating AKT SUMOylation-mediated signaling pathways

BACKGROUND

The SUMO-activating enzyme SAE1 is indispensable for protein SUMOylation. A dysregulation of SAE1 expression involves in progression of several human cancers. However, its biological roles of SAE1 in glioma are unclear by now.

METHODS

The differential proteome between human glioma tissues and para-cancerous brain tissues were identified by LC-MS/MS. SAE1 expression was further assessed by immunohistochemistry. The patient overall survival versus SAE1 expression level was evaluated by Kaplan-Meier method. The glioma cell growth and migration were evaluated under SAE1 overexpression or inhibition by the CCK8, transwell assay and wound healing analysis. The SUMO1 modified target proteins were enriched from total cellular or tissue proteins by incubation with the anti-SUMO1 antibody on protein-A beads overnight, then the SUMOylated proteins were detected by Western blot. Cell apoptosis and cell cycle were analyzed by flow cytometry. The nude mouse xenograft was determined glioma growth and tumorigenicity in vivo.

RESULTS

SAE1 is identified to increase in glioma tissues by a quantitative proteomic dissection, and SAE1 upregulation indicates a high level of tumor malignancy grade and a poor overall survival for glioma patients. SAE1 overexpression induces an increase of the SUMOylation and Ser473 phosphorylation of AKT, which promotes glioma cell growth in vitro and in nude mouse tumor model. On the contrary, SAE1 silence induces an obvious suppression of the SUMOylation and Ser473 phosphorylation of Akt, which inhibits glioma cell proliferation and the tumor xenograft growth through inducing cell cycle arrest at G2 phase and cell apoptosis driven by serial biochemical molecular events.

CONCLUSION

SAE1 promotes glioma cancer progression via enhancing Akt SUMOylation-mediated signaling pathway, which indicates targeting SUMOylation is a promising therapeutic strategy for human glioma.

SILAC-based quantitative MS approach for real-time recording protein-mediated cell-cell interactions

In tumor microenvironment, interactions among multiple cell types are critical for cancer progression. To understand the molecular mechanisms of these complex interplays, the secreted protein analysis between malignant cancer cells and the surrounding nonmalignant stroma is a good viewpoint to investigate cell-cell interactions. Here, we developed two stable isotope labeling of amino acids in cell culture (SILAC)-based mass spectrometry (MS)/MS approaches termed spike-in SILAC and triple-SILAC to quantify changes of protein secretion level in a cell co-cultured system. Within the co-culture system of CT26 and Ana-1 cells, the spike-in SILAC and triple-SILAC MS approaches are sensitive to quantitatively measure protein secretion changes. Three representative quantified proteins (Galectin-1, Cathepsin L1 and Thrombospondin-1) by two SILAC-based MS methods were further validated by Western blotting, and the coming result matched well with SILACs’. We further applied these two SILACs to human cell lines, NCM460 and HT29 co-culture system, for evaluating the feasibility, which confirmed the spike-in and triple SILAC were capable of monitoring the changed secreted proteins of human cell lines. Considering these two strategies in time consuming, sample complexity and proteome coverage, the triple-SILAC way shows more efficiency and economy for real-time recording secreted protein levels in tumor microenvironment.

STC2 promotes the epithelial-mesenchymal transition of colorectal cancer cells through AKT-ERK signaling pathways

The STC2 protein involves in carcinogenesis and progression of many cancers. It remains unclear how STC2 regulates the epithelial-mesenchymal transition (EMT) process and colorectal cancer (CRC) development. Here we systematically investigated STC2-activated early occurrence of EMT and CRC cell migration in vitro, clinical associations of STC2 with CRC development and patient survival. The secretion and expression level of STC2 were both greatly increased in EMT cells and CRC cells compared with the normal epithelial NCM460 cells. And the conditioned media from EMT cells stimulated epithelia and colon cancer cells to obtain EMT characteristics. STC2 overexpression promoted CRC cell growth and cell migration in vitro, and STC2 enhanced tumor growth in a mouse CRC-xenograft model. Corresponding to EMT marker expression changes, several critical signaling pathway molecules including pERK, pAKT, PI3K and Ras were remarkably increased either in NCM460 cells transfected with STC2 plasmids or in cells induced with exogenous STC2 protein. However blocking AKT-ERK signaling pathways attenuated STC2-activated EMT process. Furthermore the elevated STC2 expressions were also confirmed in 77 clinical tumor tissues and sera from CRC patients, and the increased STC2 in tumor tissues and sera correlated with tumor pathologic stage and poor survival for CRC patients. In conclusion, STC2 promotes CRC tumorigenesis and EMT progression through activating ERK/MEK and PI3K/AKT signaling pathways. STC2 protein is also a potential tumor biomarker for CRC diagnosis and prognosis.

Inhibition of HSP90 sensitizes a novel Raf/ERK dual inhibitor CY-9d in triple-negative breast cancer cells

Raf and extracellular signal-regulated kinases (ERK) are both important therapeutic targets in the mitogen-activated protein kinase (MAPK) pathway, and play crucial roles in the apoptosis resistance of breast cancer cells. In the present study, cytotoxic and apoptosis-inducing activities of the Raf/ERK dual inhibitor CY-9d were found to be restricted in triple negative breast cancer (TNBC) cells compared with ER/PR-positive cells. Based on the analysis of differentially expressed proteins using a quantitative proteomic iTRAQ method and bioinformatics analysis, HSP90 was found to identify as a potential mediator between Raf and ERK in TNBC cells. Western blotting and RNA interference suggested that down-regulated IQGAP1 can attenuate the routine Raf/MEK/ERK cascade and recruit HSP90 as a bypass pathway. Simultaneous treatment with the HSP90 inhibitor and CY-9d at sub-therapeutic doses was found to produce synergistic therapeutic and apoptosis-inducing effects in TNBC cells. Moreover, CY-9d was also found to suppress breast cancer growth, inhibit the activation of Raf/ERK, and induce mitochondrial apoptosis in vivo without remarkable toxicity. These results support the combination of HSP90 and Raf/ERK inhibitors as a potential target therapeutic strategy with enhanced tumor growth suppression, downstream pathway blockade, and greater induction of apoptosis.

Antineoplastic Effects of Honokiol on Melanoma

Honokiol, a plant lignan has been shown to have antineoplastic effects against nonmelanoma skin cancer developments in mice. In this study, antineoplastic effects of honokiol were investigated in malignant melanoma models. In vitro effects of honokiol treatment on SKMEL-2 and UACC-62 melanoma cells were evaluated by measuring the cell viability, proliferation, apoptosis, cell cycle analysis, and expressions of various proteins associated with cell cycle progression and apoptosis. For the in vivo study, male nude mice inoculated with SKMEL-2 or UACC-62 cells received injections of sesame oil or honokiol for two to seven weeks. In vitro honokiol treatment caused significant decrease in cell viability, proliferation, cell cycle arrest, increased apoptosis, and modulation of apoptotic and cell cycle regulatory proteins. Honokiol caused an accumulation of cells in the G2/M phase of the cell cycle in SKMEL-2 and G0/G1 phase in UACC-62 cells. An elevated level of caspases and PARP were observed in both cell lines treated with honokiol. A decrease in the expression of various cell cycle regulatory proteins was also observed in honokiol treated cells. Honokiol caused a significant reduction of tumor growth in SKMEL-2 and UACC-62 melanoma xenografts. These findings suggest that honokiol is a good candidate for further studies as a possible treatment for malignant melanoma.

Antioxidant, antitumor and immunomodulatory activities of water-soluble polysaccharides in Abrus cantoniensis

Abrus cantoniensis is a vegetative food in tropical areas of Asia and claimed as folk beverages and soups consumed for cleansing liver toxicants and preventing liver diseases. Polysaccharides (ACP-І and ACP-II) were extracted with hot water from A. cantoniensis, and isolated by DEAE cellulose chromatography. The chemical properties as well as antioxidant, antitumor and immunomodulatory activities of ACP-I and ACP-II were investigated. The results showed that the ACP-I (9.09kDa) contained only glucose and ACP-II (38.45kDa) consisted of rhamnose, arabinose, galactose and glucose. ACP-II exhibited higher oxygen radical absorbance capacity (ORAC) and hydroxyl radical prevention capacity (HRPC) than ACP-I with ORAC values and HRPC values of 53.42±3.32μmol Trolox equiv./g DW and 34.84±5.07μmol Trolox equiv./g DW. Besides, in the wound healing assay, ACP-II exhibited potent migration inhibitory effects on MCF-7 cells. ACP-II could also significantly stimulate the proliferation of splenocytes and thymocytes, and enhanced NO production of peritoneal macrophages. These findings suggest that the polysaccharide ACP-II in A. cantoniensis could be served as a novel potential functional food.

Proteomic Analysis of Anticancer TCMs Targeted at Mitochondria

Traditional Chinese medicine (TCM) is a rich resource of anticancer drugs. Increasing bioactive natural compounds extracted from TCMs are known to exert significant antitumor effects, but the action mechanisms of TCMs are far from clear. Proteomics, a powerful platform to comprehensively profile drug-regulated proteins, has been widely applied to the mechanistic investigation of TCMs and the identification of drug targets. In this paper, we discuss several bioactive TCM products including terpenoids, flavonoids, and glycosides that were extensively investigated by proteomics to illustrate their antitumor mechanisms in various cancers. Interestingly, many of these natural compounds isolated from TCMs mostly exert their tumor-suppressing functions by specifically targeting mitochondria in cancer cells. These TCM components induce the loss of mitochondrial membrane potential, the release of cytochrome c, and the accumulation of ROS, initiating apoptosis cascade signaling. Proteomics provides systematic views that help to understand the molecular mechanisms of the TCM in tumor cells; it bears the inherent limitations in uncovering the drug-protein interactions, however. Subcellular fractionation may be coupled with proteomics to capture and identify target proteins in mitochondria-enriched lysates. Furthermore, translating mRNA analysis, a new technology profiling the drug-regulated genes in translatome level, may be integrated into the systematic investigation, revealing global information valuable for understanding the action mechanism of TCMs.

A small molecular agent YL529 inhibits VEGF-D-induced lymphangiogenesis and metastasis in preclinical tumor models in addition to its known antitumor activities

Background

The lymph node metastasis is a key early step of the tumor metastatic process. VEGFD-mediated tumor lymphangiogenesis plays a key role, since down-regulation of p-VEGFR-3 could block the lymph node metastasis. YL529 has been reported to possess potent anti-angiogenesis and antitumor activities; however, its roles in tumor-associated lymphangiogenesis and lymphatic metastasis remain unclear.

Method

We investigated the effect of YL529 on tumor-associated lymphangiogenesis and lymph node metastasis using in vitro lymph node metastasis models and in vivo subcutaneous tumor models in C57 BL/6 mice.

Result

We found that YL529 inhibited VEGF-D-induced survival, proliferation and tube-formation of Human Lymphatic Endothelial Cells. Furthermore, in established in vitro and in vivo lymph node metastasis models using VEGF-D-LL/2 cells, YL529 significantly inhibited the tumor-associated lymphangiogenesis and metastasis. At molecular level, YL529 down-regulated p-VEGFR-3, p-JNK and Bax while up-regulated Bcl-2.

Conclusion

YL529 provided the therapeutic benefits by both direct effects on tumor cells and inhibiting lymphangiogenesis and metastasis via the VEGFR-3 signaling pathway, which may have significant direct clinical implications.

Encapsulation of honokiol into self-assembled pectin nanoparticles for drug delivery to HepG2 cells

Self-assembled pectin nanoparticles was prepared and evaluated for delivering the hydrophobic drug, honokiol (HK), to HepG2 cells. These hydrophobic drug-loaded nanoparticles were developed without using any surfactant and organic solvent. Hydroxypropyl-β-cyclodextrin (HCD) was used to fabricate an inclusion complex with HK (HKHCD) to increase the solubility of the drug and thus facilitate its encapsulation and dispersion in the pectin nanoparticles. Investigation of the in vitro release indicated that the drug-loaded nanoparticles exhibited a higher drug release rate than free honokiol and an effective sustained-release. Cytotoxicity, cell apoptosis and cellular uptake studies further confirmed that the pectin nanoparticles with galactose residues generated higher cytotoxicity than free honokiol on HepG2 cells which highly expressed asialoglycoprotein receptors (ASGR). Nevertheless, these findings were not observed in ASGR-negative A549 cells under similar condition. Therefore, pectin nanoparticles demonstrated a specific active targeting ability to ASGR-positive HepG2 cells and could be used as a potential drug carrier for treatment of liver-related tumors.

Emerging role of the peroxisome proliferator-activated receptor-gamma in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the major leading cause of cancer death worldwide. Hepatitis B virus, hepatitis C virus, alcohol consumption, non-alcoholic fatty liver disease, and diabetes are the major risks for developing HCC. Until now, recurrence and metastasis are the major cause of death in HCC patients. Therefore, identification of new effective molecular targets is an urgent need for treatment of HCC. Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated nuclear receptor which could be activated by PPARγ agonists such as thiazolidinediones, and natural PPARγ ligand (such as 15-deoxy-Δ12,14-prostaglandin J₂, 15d-PGJ₂). Increasing in vitro and in vivo evidence has demonstrated that PPARγ agonists exhibit an inhibitory role on tumor cell growth, migration, and invasion, suggesting that PPARγ activation may play an important role in the regulation of growth of HCC. It has been reported that PPARγ activation by thiazolidinediones or overexpression of PPARγ by virus-mediated gene transfer has shown growth inhibitory effects in hepatoma cells, but the expression level of PPARγ in HCC tissues still remains conflicting. Notably, a novel PPARγ agonist, honokiol, has recently been found to activate the PPARγ/RXR heterodimer, and has also exhibited significant anti-cancer effects in hepatoma cells. In the present review, we summarized studies on the role and the molecular regulation of PPARγ in HCC development in vitro and in vivo. PPARγ has the potential to be a therapeutic target for future treatment of HCC.

Targeting apoptosis pathways in cancer and perspectives with natural compounds from mother nature

Although the incidences are increasing day after day, scientists and researchers taken individually or by research group are trying to fight against cancer by several ways and also by different approaches and techniques. Sesquiterpenes, flavonoids, alkaloids, diterpenoids, and polyphenolic represent a large and diverse group of naturally occurring compounds found in a variety of fruits, vegetables, and medicinal plants with various anticancer properties. In this review, our aim is to give our perspective on the current status of the natural compounds belonging to these groups and discuss their natural sources, their anticancer activity, their molecular targets, and their mechanism of actions with specific emphasis on apoptosis pathways, which may help the further design and conduct of preclinical and clinical trials. Unlike pharmaceutical drugs, the selected natural compounds induce apoptosis by targeting multiple cellular signaling pathways including transcription factors, growth factors, tumor cell survival factors, inflammatory cytokines, protein kinases, and angiogenesis that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that they provide a novel opportunity for treatment of cancer, but clinical trials are still required to further validate them in cancer chemotherapy.

Honokiol suppresses TNF-α-induced migration and matrix metalloproteinase expression by blocking NF-κB activation via the ERK signaling pathway in rat aortic smooth muscle cells

Honokiol, a small-molecule polyphenol derived and isolated from the Chinese medicinal herb Magnolia officinalis, has been shown to possess a wide range of pharmacological activities. In the present study, we aimed to investigate the effects of honokiol on tumor necrosis factor-α (TNF-α)-induced migration in rat aortic smooth muscle cells (RASMCs). We found that honokiol inhibited TNF-α-induced RASMC proliferation and migration in a dose-dependent manner. At the molecular level, pretreatment with honokiol blocked TNF-α-induced protein expression of matrix metalloproteinase (MMP)-2 and MMP-9, nuclear factor (NF)-κB activation, and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Moreover, NF-κB inhibitor (BAY 11-7028) and ERK inhibitor (U0126) also mimicked the inhibitory effects of honokiol in TNF-α-treated RASMCs. In conclusion, these results indicate that honokiol suppresses TNF-α-induced migration and MMP expression by blocking NF-κB activation via the ERK signaling pathway in RASMCs. Our findings support honokiol as a promising novel agent for the prevention and treatment of atherosclerosis.

YL529, a novel, orally available multikinase inhibitor, potently inhibits angiogenesis and tumour growth in preclinical models

BACKGROUND AND PURPOSE

Targeted chemotherapy using small-molecule inhibitors of angiogenesis and proliferation is a promising strategy for cancer therapy.

EXPERIMENTAL APPROACH

YL529 was developed via computer-aided drug design, de novo synthesis and high-throughput screening. The biochemical, pharmacodynamic and toxicological profiles of YL529 were investigated using kinase and cell viability assays, a mouse tumour cell-containing alginate bead model, a zebrafish angiogenesis model and several human tumour xenograft models in athymic mice.

KEY RESULTS

In vitro, YL529 selectively inhibited the activities of VEGFR2/VEGFR3 and serine/threonine kinase RAF kinase. YL529 inhibited VEGF165 -induced phosphorylation of VEGFR2, as well as the proliferation, migration, invasion and tube formation of human umbilical vascular endothelial cells. It also significantly blocked vascular formation and angiogenesis in the zebrafish model. Moreover, YL529 strongly attenuated the proliferation of A549 cells by disrupting the RAF/mitogen-activated protein (MAP) or extracellular signal-regulated kinase (Erk) kinase (MEK) kinase kinase/MAPK pathway. Oral administration of YL529 (37.5-150 mg(-1) ·kg(-1) ·day(-1) ) to nude mice bearing established tumour xenografts significantly prevented the growth (60-80%) of A549, SPC-A1, A375, OS-RC-2 and HCT116 tumours without detectable toxicity. YL529 markedly reduced microvessel density and increased tumour cell apoptosis in the tumours formed in mice inoculated with the lung cancer cells, SPC-A1 and A549, and the colon carcinoma cells, HCT116.

CONCLUSIONS AND IMPLICATIONS

YL529, an orally active multikinase inhibitor, shows therapeutic potential for solid tumours, and warrants further investigation as a possible anticancer agent.

Chlamydophila (Chlamydia) pneumoniae infection promotes vascular smooth muscle cell adhesion and migration through IQ domain GTPase-activating protein 1

The mechanisms for Chlamydophila (Chlamydia) pneumoniae (C. pneumoniae) infection-induced atherosclerosis are still unclear. Cell adhesion has important roles in vascular smooth muscle cell (VSMC) migration required in the development of atherosclerosis. However, it is still unknown whether IQ domain GTPase-activating protein 1 (IQGAP1) plays pivotal roles in C. pneumoniae infection-induced the adhesion and migration of rat primary VSMCs. Accordingly, in this study, we demonstrated that rat primary VSMC adhesion (P < 0.001) and migration (P < 0.01) measured by cell adhesion assay and Transwell assay, respectively, were significantly enhanced after C. pneumoniae infection. Reverse transcription-polymerase chain reaction analysis revealed that the mRNA expression levels of IQGAP1 in the infected rat primary VSMCs were found to increase gradually to reach a peak and then decrease gradually to a level similar to the control. We further showed that the increases in rat primary VSMC adhesion to Matrigel (P < 0.001) and migration (P < 0.01) caused by C. pneumoniae infection were markedly inhibited after IQGAP1 knockdown by a pool of four short hairpin RNAs. Taken together, our results suggest that C. pneumoniae infection may promote the adhesion and migration of VSMCs possibly by upregulating the IQGAP1 expression.

Piwil2 suppresses p53 by inducing phosphorylation of signal transducer and activator of transcription 3 in tumor cells

Piwi proteins have been implicated in germ cell proliferation, differentiation, germline stem cell maintenance and transposon control in germline from Drosophila to mammals. The Piwi-like2 (piwil2) gene is mainly expressed in testis or embryonic cells among normal tissues but widely expressed in tumors. However, it remains to be fully determined through which mechanism piwil2 is involved in tumorigenesis. Here we report that Human piwil2, or Hili represses the tumor suppressor P53 in human cancer cells. Immunoprecipitation analysis shows that Piwil2 can directly associate with Signal Transducer and Activator of Transcription 3 (STAT3) protein via its PAZ domain and form a Piwil2/STAT3/c-Src triple protein-protein complex. Furthermore, STAT3 is phosphorylated by c-Src and translocated to nucleus, then binds to P53 promoter and represses its transcription. The present study demonstrated that Piwil2 plays a role in anti-apoptosis in tumor cells possessing P53 as a positive regulator of STAT3 signaling pathway, providing novel sights into roles of Piwil2 in tumorigenesis.

Comparisons of three polyethyleneimine-derived nanoparticles as a gene therapy delivery system for renal cell carcinoma

Background

Polyethyleneimine (PEI), which can interact with negatively charged DNA through electrostatic interaction to form nanocomplexes, has been widely attempted to use as a gene delivery system. However, PEI has some defects that are not fit for keeping on gene expression. Therefore, some modifications against PEI properties have been done to improve their application value in gene delivery. In this study, three modified PEI derivatives, including poly(ε-caprolactone)-pluronic-poly(ε-caprolactone) grafted PEI (PCFC-g-PEI), folic acid-PCFC-isophorone diidocyanate-PEI (FA-PEAs) and heparin-PEI (HPEI), were evaluated in terms of their cytotoxicity and transfection efficiency in vitro and in vivo in order to ascertain their potential application in gene therapy.

Methods

MTT assay and a marker GFP gene, encoding green fluorescent protein, were used to evaluate cell toxicity and transfection activity of the three modified PEI in vitro. Renal cell carcinoma (RCC) models were established in BALB/c nude mice inoculated with OS-RC-2 cells to detect the gene therapy effects using the three PEI-derived nanoparticles as gene delivery vehicles. The expression status of a target gene Von Hippel-Lindau (VHL) in treated tumor tissues was analyzed by semiquantitative RT-PCR and immunohistochemistry.

Results

Each of three modified PEI-derived biomaterials had an increased transfection efficiency and a lower cytotoxicity compared with its precursor PEI with 25-kD or 2-kD molecule weight in vitro. And the mean tumor volume was obviously decreased 30% by using FA-PEAs to transfer VHL plasmids to treat mice RCC models. The VHL gene expression was greatly improved in the VHL-treated group. While there was no obvious tumor inhibition treated by PCFC-g-PEI:VHL and HPEI:VHL complexes.

Conclusions

The three modified PEI-derived biomaterials, including PCFC-g-PEI, FA-PEAs and HPEI, had an increased transfection efficiency in vitro and obviously lower toxicities compared with their precursor PEI molecules. The FA-PEAs probably provide a potential gene delivery system to treat RCC even other cancers in future.