Anti-metastatic action of anacardic acid targets VEGF-induced signalling pathways in epithelial to mesenchymal transition

Role of transforming growth factor-β1 pathway in angiogenesis induced by chronic stress in colorectal cancer

BACKGROUND

Chronic stress can induce stress-related hormones; norepinephrine (NE) is considered to have the highest potential in cancer. NE can stimulate the expression of hypoxia-inducible factor-1α (HIF-1α), which is associated with vascular endothelial growth factor (VEGF) secretion and tumor angiogenesis. However, the underlying mechanisms are poorly understood.

METHODS

Tumor-bearing mice were subjected to chronic restraint stress and treated with normal saline, human monoclonal VEGF-A neutralizing antibody bevacizumab, or β-adrenergic receptor (β-AR) antagonist (propranolol). Tumor growth and vessel density were also evaluated. Human colorectal adenocarcinoma cells were treated with NE, propranolol, or the inhibitor of transforming growth factor-β (TGF-β) receptor Type I kinase (Ly2157299) in vitro. TGF-β1 in mouse serum and cell culture supernatants was quantified using ELISA. The expression of HIF-1α was measured using Real time-PCR and western blotting. Cell migration and invasion were tested.

RESULTS

Chronic restraint stress attenuated the efficacy of bevacizumab and promoted tumor growth and angiogenesis in a colorectal tumor model. Propranolol blocked this effect and inhibited TGF-β1 elevation caused by chronic restraint stress or NE. NE upregulated HIF-1α expression, which was reversed by propranolol or Ly2157299. Propranolol and Ly2157199 blocked NE-stimulated cancer cell migration and invasion.

CONCLUSIONS

Our results demonstrate the effect of NE on tumor angiogenesis and the critical role of TGF-β1 signaling during this process. In addition, β-AR/TGF-β1 signaling/HIF-1α/VEGF is a potential signaling pathway. This study also indicates that psychosocial stress might be a risk factor which weakens the efficacy of anti-angiogenic therapy.

Small molecules as cancer targeting ligands: Shifting the paradigm

Conventional chemotherapeutics exploration is hampered due to their nonspecific distribution leading to unintended serious toxicity. Toxicity is so severe that deciding to go for chemotherapy becomes a question of concern for many terminally ill cancer patients. However, with evolving times nanotechnology assisted in reducing the haywire distribution and channelizing the movement of drug-enclosing drug delivery systems to cancer cells to a greater extent, yet toxicity issues still could not be obliterated. Thus, active targeting appeared as a refuge, where ligands actively or specifically deliver linked chemotherapeutics and carriers to cancer cells. For a very long time, large molecule weight/macromolecular ligands (peptides and big polymers) were considered the first choice for ligand-directed active cancer targeting, due to their specificity towards overexpressed native cancer receptors. However, complex characterization, instability, and the expensive nature demanded to reconnoitre better alternatives for macromolecule ligands. The concept of small molecules as ligands emerged from the idea that few chemical molecules including chemotherapeutics have a higher affinity for cancer receptors, which are overexpressed on cell membranes, and may have the ability to assist in drug cellular uptake through endocytosis. But now the question is, can they assist the conjugated macro cargos to enter the cell or not? This present review will provide a holistic overview of the small molecule ligands explored till now.

Association between the VEGFR-2 -604T/C polymorphism (rs2071559) and type 2 diabetic retinopathy

This retrospective case-control study examined the association between the rs2071559 (-604T/C) single nucleotide polymorphism (SNP) in the vascular endothelial growth factor receptor (VEGFR)-2 gene and the risk of diabetic retinopathy (DR) in Northern Han Chinese. This study included patients diagnosed with diabetes mellitus (DM) in Shijiazhuang between 07/2014 and 07/2016. The healthy controls were unrelated individuals who received routine physical examinations. The diabetic patients were grouped as DM (diabetes but no fundus examination abnormalities), proliferative DR (PDR), and non-proliferative DR (NPDR). Finally, 438 patients were included: 114 controls and 123, 105, and 96 patients in the DM, NPDR, and PDR groups, respectively. In the multivariable analyses and all genetic models, the VEGFR-2 rs2071559 SNP was not associated with DR (among all diabetic patients) or with PDR (among the patients with DR) after adjustment for age, sex, duration of DM, blood glucose, systolic blood pressure, diastolic blood pressure, and body mass index (all P > 0.05). In conclusion, the VEGFR-2- 604T/C rs2071559 SNP is not associated with DR or PDR in the Han Chinese population of Shijiazhuang (China).

Regulation of epithelial-mesenchymal transition by protein lysine acetylation

The epithelial-mesenchymal transition (EMT) is a vital driver of tumor progression. It is a well-known and complex trans-differentiation process in which epithelial cells undergo morphogenetic changes with loss of apical-basal polarity, but acquire spindle-shaped mesenchymal phenotypes. Lysine acetylation is a type of protein modification that favors reversibly altering the structure and function of target molecules via the modulation of lysine acetyltransferases (KATs), as well as lysine deacetylases (KDACs). To date, research has found that histones and non-histone proteins can be acetylated to facilitate EMT. Interestingly, histone acetylation is a type of epigenetic regulation that is capable of modulating the acetylation levels of distinct histones at the promoters of EMT-related markers, EMT-inducing transcription factors (EMT-TFs), and EMT-related long non-coding RNAs to control EMT. However, non-histone acetylation is a post-translational modification, and its effect on EMT mainly relies on modulating the acetylation of EMT marker proteins, EMT-TFs, and EMT-related signal transduction molecules. In addition, several inhibitors against KATs and KDACs have been developed, some of which can suppress the development of different cancers by targeting EMT. In this review, we discuss the complex biological roles and molecular mechanisms underlying histone acetylation and non-histone protein acetylation in the control of EMT, highlighting lysine acetylation as potential strategy for the treatment of cancer through the regulation of EMT.

Association of the VEGFR2 single nucleotide polymorphism rs2305948 with glioma risk

BACKGROUND

Many studies have reported a relationship between the vascular endothelial growth factor receptor 2 single nucleotide polymorphism (SNP) rs2305948 and glioma, but their conclusions have been controversial. A meta-analysis was performed to assess the association between rs2305948 and glioma susceptibility.

METHODS

Inclusion criteria and a strategy for screening of original literature were created. Eligible articles on the correlation between the SNP rs2305948 and glioma were identified in the PubMed, Embase, Web of Science, Cochrane Library, CNKI and Wanfang databases. After extracting the data, Stata 12. 0 software was used to perform statistical analysis under 5 genetic models and to calculate the combined odds ratio (OR) value and its 95% confidence interval (CI).

RESULTS

Four case-control studies including 1595 cases and 1657 controls were entered into the study. The overall analysis showed that no obvious association existed between rs2305948 and glioma risk (allele: OR = 1.20, 95% CI = 0.93-1.54, P = .162; dominant: OR = 1.17, 95% CI = 0.93-1.46, P = .174; recessive: OR = 1.72, 95% CI = 0.94-3.15, P = .076; heterozygous: OR = 1.11, 95% CI = 0.94-1.30, P = .226; homozygous: OR = 1.74, 95% CI = 0.92-3.29, P = .088). The subgroup analysis suggested that the SNP rs2305948 was related to glioma susceptibility under allele, dominant, recessive and homozygote models in the Asian population (allele: OR = 1.34, 95% CI = 1.16-1.55, P < .001; recessive: OR = 2.24, 95% CI = 1.49-3.36, P < .001; homozygous: OR = 2.32, 95% CI = 1.54-3.50, P < .001).

CONCLUSION

The vascular endothelial growth factor receptor 2 rs2305948 gene polymorphism may be related to glioma susceptibility in the Asian population. However, the association is not clear in non-Asian populations, for which there has been less research.

Bioinformatics analysis of microarray data reveals epithelial-mesenchymal-transition in pediatric ependymoma

The objectives of this study were to explore the possible mechanisms of pediatric ependymoma using bioinformatics methods and provide potential genes and signaling pathways for pediatric ependymoma study. The data of GES74195 from Gene Expression Ominibus was analyzed by R language for pediatric ependymoma study. The differentially expressed genes were explored using gene set enrichment analysis, search tool for the retrieval of interacting genes, Cytoscape as well as other mainstream bioinformatics methods. Extracellular matrix-receptors interaction pathways and focal adhesion pathway were demonstrated as the key signaling pathway for pediatric ependymoma. The potential hub genes enriched in the two signaling pathways were regarded as final hub genes for this microarray analysis. The development and progression of pediatric ependymoma were associated with epithelial-mesenchymal-transition. Various potential hub genes and potential key signaling pathways in order to further explore their values in the diagnosis and treatment of this disease in the future.

Integration of medicinal plants into the traditional system of medicine for the treatment of cancer in Sokoto State, Nigeria

This study was designed to explore and record various medicinal plants integrated into the traditional system of medicine for the treatment of cancer. The traditional system of medicine is a routine practiced among the indigenous ethnic groups of Sokoto state. A semi-structured questionnaire was designed and used for data collection around the selected Local Government Areas. A substantial number of plant species were identified, recorded, and collected for preservation. Data collected for each specie was analysed to assess its frequent use among the medicinal plants. A total of 67 species belonging to 31 families have been identified and recorded. Out of the 473 frequency of citation (FC), Acacia nilotica was the most frequently cited specie (32 FC, 64% FC, 0.6 RFC), followed by Guiera senegalensis (27 FC, 54% FC, 0.5 RFC), Erythrina sigmoidea (17 FC, 34% FC, 0.3 RFC), and subsequently Combretum camporum (15 FC, 30% FC, 0.3 RFC). The most common parts of the plants used include the barks (55.2%), the roots (53.2%), and the leaves (41.8%). Additionally, decoction (74.6%), powdered form (49.3%), and maceration (46.3%) are the most frequently used mode of preparation. The historical knowledge of a traditional system of medicine practiced by the native traditional healers of Sokoto for the treatment of cancer has been documented. The present study further provides a baseline for future pharmacological investigations into the beneficial effects of such medicinal plants for the treatment of cancer.

Toxicological and genotoxic evaluation of anacardic acid loaded-zein nanoparticles in mice

Anacardic acid extracted from cashew nut shells of Anacardium occidentale L has demonstrated important biological activities, such as antibacterial activity against the cariogenic specie Streptococcus mutans. Zein nanoparticles containing anacardic acid (9.375 μg/mL) were evaluated in terms of toxicity and genotoxicity in vivo. The subacute toxicity assay was used to evaluate the cumulative effects of the oral administration of nanoencapsulated anacardic acid at 2.25 and 112.5 μg/kg for 7 days in mice, simulating a mouth rinse short-term clinical course treatment. Blank zein nanoparticles and saline solution 0.9 % were used as negative controls. Peripheral blood samples were collected to evaluate the genotoxicity in polychromatic erythrocytes using the micronucleus test. The animals were anesthetized, euthanized and the target organs collected, weighed and submitted to histopathological analysis. Liver, kidney and spleen relative weights did not change. Nevertheless, stomach, lung and heart increased the relative weights in the group receiving the highest dose, in which occasional histopathological findings were also identified. Both doses maintained the micronucleus frequency within the normal range and the animals treated with the highest dose presented a discrete weight lost, which could explain the organs' relative weight reductions. Blank and anacardic acid loaded zein nanoparticles were nontoxic when administered repeatedly for 7 days, as no relevant histopathological changes neither genotoxicity were observed. These preparations demonstrated limited toxicity under the conditions used in this study and could become an antibacterial alternative for preventing/treating oral infections in short-term treatments.

Exploring an interesting dual functionality of anacardic acid for efficient paclitaxel delivery in breast cancer therapy

Aim: To explore the potential of paclitaxel (PTX)-loaded anacardic acid conjugated hydrophobized gelatin nanoparticles. Materials & methods: Nanoparticles prepared by nanoprecipitation technique were evaluated for various quality attributes (particle size, % entrapment efficiency) in vitro drug release, MCF-7 cell uptake, cell cytotoxicity, in vivo pharmacokinetics, antitumor efficacy and toxicity. Results: The nanoparticles (250–300 nm, 74% entrapment efficiency) showed approximately 2.26-fold higher apoptosis index and approximately 5.86-fold reduction in IC50 value compared with PTX in MCF-7 cells. Also, approximately 3.51- and 1.36-fold increase in area under the curve compared with Intaxel® and Nanoxel™ (both from Fresenius Kabi, Gurugram, India) was achieved. Significant tumor burden reduction (∼60%) and reduced toxicity was observed compared with marketed formulations. Conclusion: The hydrophobized gelatin nanoparticles displayed promising therapeutic potential, paving a new path for efficient PTX delivery.

Ginkgolic acid inhibits the invasiveness of colon cancer cells through AMPK activation

Tumor cell invasion and metastasis are important processes in colorectal cancer that exert negative effects on patient outcomes; consequently, a prominent topic in the field of colorectal cancer study is the identification of safe and affordable anticancer drugs against cell invasion and metastasis, with limited side effects. Ginkgolic acid is a phenolic acid extracted from ginkgo fruit, ginkgo exotesta and ginkgo leaves. Previous studies have indicated that ginkgolic acid inhibits tumor growth and invasion in a number of types of cancer; however, limited studies have considered the effects of ginkgolic acid on colon cancer. In the present study, SW480 colon cancer cells were treated with a range of concentrations of ginkgolic acid; tetrazolium dye-based MTT, wound-scratch and transwell migration assays were performed to investigate the effects on the proliferation, migration and invasion of colon cancer cells, and potential mechanisms for the effects were explored. The results indicated that ginkgolic acid reduced the proliferation and significantly inhibited the migration and invasion of SW480 cells in a concentration-dependent manner. Additional experiments indicated that ginkgolic acid significantly decreased the expression of invasion-associated proteins, including matrix metalloproteinase (MMP)-2, MMP-9, urinary-type plasminogen activator and C-X-C chemokine receptor type 4, and activated adenosine monophosphate activated protein kinase (AMPK) in SW480 cells. Small interfering RNA silencing of AMPK expression reversed the effect of ginkgolic acid on the expression of invasion-associated proteins. This result suggested that ginkgolic acid inhibited the proliferation, migration and invasion of SW480 colon cancer cells by inducing AMPK activation and inhibiting the expression of invasion-associated proteins.

Aberrant cytokine secretion and zinc uptake in chronic cadmium-exposed lung epithelial cells

PURPOSE

Our previous results showed that cadmium (Cd)-adapted lung epithelial cells (LECs) developed resistance to apoptosis due to non-responsiveness of the c-Jun N-terminal kinase pathway and augmented expression of cytokeratin 8. Since cellular Cd entry is a prerequisite in order for Cd to elicit its cytotoxicity, therefore, we wonder if there are differential metal ion transport ability and also other phenotypic changes that occurred in these Cd-resistant LECs.

EXPERIMENTAL DESIGN AND RESULTS

Here, we explored further and found that the zinc (Zn) importer Zip8 was stably abolished in these cells along with a marked decrease of Cd and Zn accumulation. Moreover, by cell migration assays and cytokine antibody array analysis, we found that Cd-adapted cells exhibit enhanced migratory ability possibly due to elevated secretions of vascular endothelial growth factor and macrophage inflammatory protein-3 alpha (MIP-3α).

CONCLUSION AND CLINICAL RELEVANCE

Taken together, our results show that during chronic Cd exposure, lung cells antagonize excessive cellular Cd-influx by abolishing Zip8 expression to reduce Cd-toxicity; however, this also renders cells with a diminished Zn uptake. The imbalance of Zn homeostasis and elevation of angiogenic and epithelial-mesenchymal transition-promoting cytokines in Cd-adapted cells might thus likely promote Zn deficiency, angiogenesis, and cell invasion.

Combinatorial treatment with anacardic acid followed by TRAIL augments induction of apoptosis in TRAIL resistant cancer cells by the regulation of p53, MAPK and NFκβ pathways

TRAIL, an apoptosis inducing cytokine currently in phase II clinical trial, was investigated for its capability to induce apoptosis in six different human tumor cell lines out of which three cell lines showed resistance to TRAIL induced apoptosis. To investigate whether Anacardic acid (A1) an active component of Anacardium occidentale can sensitize the resistant cell lines to TRAIL induced apoptosis, we treated the resistant cells with suboptimal concentration of A1 and showed that it is a potent enhancer of TRAIL induced apoptosis which up-regulates the expression of both DR4 and DR5 receptors, which has been observed in the cellular, protein and mRNA levels. The death receptors upregulation consequent to A1 treatment was corroborated by the activation of p53 as well as phosphorylation of p38 and JNK MAP kinases and concomitant inactivation of NFκβ and ERK signaling cascades. Also, A1 modulated the expression of key apoptotic players like Bax, Bcl-2 and CAD along with the abatement of tumor angiogenesis in vivo in EAT mouse model. Thus, post A1 treatment the TRAIL resistant cells turned into TRAIL sensitive cells. Hence our results demonstrate that A1 can synergize TRAIL induced apoptosis through the upregulation of death receptors and downregulation of anti-apoptotic proteins in cancer context.

Pathologic features of aggressive vulvar carcinoma are associated with epithelial-mesenchymal transition

Factors contributing to aggressive behavior in vulvar squamous cell carcinoma (vSCC) are poorly defined; however, a recent study has shown that vSCCs with an infiltrative pattern of invasion and fibromyxoid stroma are associated with worse outcomes than tumors with a pushing or nested pattern of invasion and lymphoplasmacytic stroma. Epithelial-mesenchymal transition (EMT) has been associated with tumor progression in a number of malignancies, and this study proposes that EMT contributes to tumor aggressiveness in this subset of vSCC. Immunohistochemistry was used to detect nuclear localization of β-catenin, loss of E-cadherin, and presence of vimentin in 58 cases of vSCC. The association of these phenotypic changes with pathologic features and clinical outcomes was tested using Fisher's exact and χ(2) analyses (significance at P≤.05). EMT-associated features were identified in 45 of 58 cases (78%) with 28 cases exhibiting more than one feature. Nuclear β-catenin and presence of vimentin were significantly more likely to occur in tumors with an infiltrative pattern of invasion or a fibromyxoid stromal response. Loss of E-cadherin was significantly associated with an infiltrative pattern, but not a fibromyxoid stroma. Risk for tumor recurrence was significantly increased in tumors with nuclear localization of β-catenin alone or in tumors displaying multiple EMT-associated features. These results suggest that the development of EMT may be a mechanism by which infiltrative vulvar tumors with a fibromyxoid stromal response behave more aggressively and convey worse outcomes than tumors that do not exhibit these pathologic features.