Protocatechuic acid inhibits lung cancer cells by modulating FAK, MAPK, and NF-κB pathways

Effect of the combined binding of topotecan and catechin/protocatechuic acid to a pH-sensitive DNA tetrahedron on release and cytotoxicity: Spectroscopic and calorimetric studies

The therapeutic efficacy of chemotherapy drugs can be effectively improved through the dual effects of their combination with natural polyphenols and the delivery of targeted DNA nanostructures. In this work, the interactions of topotecan (TPT), (+)-catechin (CAT), or protocatechuic acid (PCA) with a pH-sensitive DNA tetrahedron (MUC1-TD) in the binary and ternary systems at pHs 5.0 and 7.4 were investigated by fluorescence spectroscopy and calorimetry. The intercalative binding mode of TPT/CAT/PC to MUC1-TD was confirmed, and their affinity was ranked in the order of PCA > CAT > TPT. The effects of the pH-sensitivity of MUC1-TD and different molecular structures of CAT and PCA on the loading, release, and cytotoxicity of TPT were discussed. The weakened interaction under acidic conditions and the co-loading of CAT/PCA, especially PCA, improved the release of TPT loaded by MUC1-TD. The targeting of MUC1-TD and the synergistic effect with CAT/PCA, especially CAT, enhanced the cytotoxicity of TPT on A549 cells. For L02 cells, the protective effect of CAT/PCA reduced the damage caused by TPT. The single or combined TPT loaded by MUC1-TD was mainly concentrated in the nucleus of A549 cells. This work will provide key information for the combined application of TPT and CAT/PCA loaded by DNA nanostructures to improve chemotherapy efficacy and reduce side effects.

The Cancer-Protective Potential of Protocatechuic Acid: A Narrative Review

Cancer is one of the leading causes of death worldwide, making the search for alternatives for its control a critical issue. In this context, exploring alternatives from natural sources, such as certain vegetables containing a variety of secondary metabolites with beneficial effects on the body and that play a crucial role in the fight against cancer, is essential. Among the compounds with the greatest efficacy in controlling this disease, those with antioxidant activity, particularly phenolic com-pounds, stand out. A remarkable example of this group is protocatechuic acid (PCA), which has been the subject of various revealing research on its activities in different areas. These studies sustain that protocatechuic acid has anti-inflammatory, antimutagenic, antidiabetic, antiulcer, antiviral, antifibrogenic, antiallergic, neuroprotective, antibacterial, anticancer, antiosteoporotic, anti-aging, and analgesic properties, in addition to offering protection against metabolic syndrome and con-tributing to the preservation of hepatic, renal, and reproductive functionality. Therefore, this paper aims to review the biological activities of PCA, focusing on its anticancer potential and its in-volvement in the control of various molecular pathways involved in tumor development, sup-porting its option as a promising alternative for cancer treatment.

Current advances in nanoformulations of therapeutic agents targeting tumor microenvironment to overcome drug resistance

The tumor microenvironment (TME) plays a pivotal role in cancer development and progression. In this line, revealing the precise mechanisms of the TME and associated signaling pathways of tumor resistance could pave the road for cancer prevention and efficient treatment. The use of nanomedicine could be a step forward in overcoming the barriers in tumor-targeted therapy. Novel delivery systems benefit from enhanced permeability and retention effect, decreasing tumor resistance, reducing tumor hypoxia, and targeting tumor-associated factors, including immune cells, endothelial cells, and fibroblasts. Emerging evidence also indicates the engagement of multiple dysregulated mediators in the TME, such as matrix metalloproteinase, vascular endothelial growth factor, cytokines/chemokines, Wnt/β-catenin, Notch, Hedgehog, and related inflammatory and apoptotic pathways. Hence, investigating novel multitargeted agents using a novel delivery system could be a promising strategy for regulating TME and drug resistance. In recent years, small molecules from natural sources have shown favorable anticancer responses by targeting TME components. Nanoformulations of natural compounds are promising therapeutic agents in simultaneously targeting multiple dysregulated factors and mediators of TME, reducing tumor resistance mechanisms, overcoming interstitial fluid pressure and pericyte coverage, and involvement of basement membrane. The novel nanoformulations employ a vascular normalization strategy, stromal/matrix normalization, and stress alleviation mechanisms to exert higher efficacy and lower side effects. Accordingly, the nanoformulations of anticancer monoclonal antibodies and conventional chemotherapeutic agents also improved their efficacy and lessened the pharmacokinetic limitations. Additionally, the coadministration of nanoformulations of natural compounds along with conventional chemotherapeutic agents, monoclonal antibodies, and nanomedicine-based radiotherapy exhibits encouraging results. This critical review evaluates the current body of knowledge in targeting TME components by nanoformulation-based delivery systems of natural small molecules, monoclonal antibodies, conventional chemotherapeutic agents, and combination therapies in both preclinical and clinical settings. Current challenges, pitfalls, limitations, and future perspectives are also discussed.

Biocompatible and biodegradable copper-protocatechuic metal-organic frameworks as rifampicin carrier

Tuberculosis (TB) is a disease caused by the M. tuberculosis bacteria infection and is listed as one of the deadliest diseases to date. Despite the development of antituberculosis drugs, the need for long-term drug consumption and low patient commitment are obstacles to the success of TB treatment. A continuous drug delivery system that has a long-term effect is needed to reduce routine drug consumption intervals, suppress infection, and prevent the emergence of drug-resistant strains of M. tuberculosis. For this reason, biomolecule metal-organic framework (BioMOF) with good biocompatibility, nontoxicity, bioactivity, and high stability are becoming potential drug carriers. This study used a bioactive protocatechuic acid (PCA) as organic linker to prepare copper-based BioMOF Cu-PCA under base-modulated conditions. Detailed crystal analysis by the powder X-ray diffraction demonstrated that the Cu-PCA, with a chemical formula of C₁₄H₁₆O₁₃Cu₃, crystalizes as triclinic in space group P1. Comprehensive physicochemical characterizations were provided using FTIR, SEM, XPS, TGA, EA, and N₂ sorption. As a drug carrier, Cu-PCA showed a high maximum rifampicin (RIF) drug loading of 443.01 mg/g. Upon resuspension in PBS, the RIF and linkers release profile exhibited two-stage release kinetic profiles, which are well described by the Biphasic Dose Response (BiDoseResp) model. A complete release of these compounds (RIF and PCA) was achieved after ~9 h of mixing in PBS. Cu-PCA and RIF@Cu-PCA possessed antibacterial activity against Escherichia coli, and good biocompatibility is evidenced by the high viability of MH-S mice alveolar macrophage cells upon supplementations.

Inhibiting Angiogenesis by Anti-Cancer Saponins: From Phytochemistry to Cellular Signaling Pathways

Saponins are one of the broadest classes of high-molecular-weight natural compounds, consisting mainly of a non-polar moiety with 27 to 30 carbons and a polar moiety containing sugars attached to the sapogenin structure. Saponins are found in more than 100 plant families as well as found in marine organisms. Saponins have several therapeutic effects, including their administration in the treatment of various cancers. These compounds also reveal noteworthy anti-angiogenesis effects as one of the critical strategies for inhibiting cancer growth and metastasis. In this study, a comprehensive review is performed on electronic databases, including PubMed, Scopus, ScienceDirect, and ProQuest. Accordingly, the structural characteristics of triterpenoid/steroid saponins and their anti-cancer effects were highlighted, focusing on their anti-angiogenic effects and related mechanisms. Consequently, the anti-angiogenic effects of saponins, inhibiting the expression of genes related to vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1-α (HIF-1α) are two main anti-angiogenic mechanisms of triterpenoid and steroidal saponins. The inhibition of inflammatory signaling pathways that stimulate angiogenesis, such as pro-inflammatory cytokines, mitogen-activated protein kinase (MAPKs), and phosphoinositide 3-kinases/protein kinase B (PI3K/Akt), are other anti-angiogenic mechanisms of saponins. Furthermore, the anti-angiogenic and anti-cancer activity of saponins was closely related to the binding site of the sugar moiety, the type and number of their monosaccharide units, as well as the presence of some functional groups in their aglycone structure. Therefore, saponins are suitable candidates for cancer treatment by inhibiting angiogenesis, for which extensive pre-clinical and comprehensive clinical trial studies are recommended.

Gallic acid markedly stimulates GLUT1-mediated glucose uptake by the AsPC-1 pancreatic cancer cell line

Phenolic acids are recognized as chemopreventive and chemotherapeutic agents. Altered glucose and glutamine metabolism are recognized hallmarks of cancer cells. We aimed to test the influence of phenolic acids on glucose and glutamine cellular uptake by a breast (MCF-7) and a pancreatic (AsPC-1) cancer cell line. Several phenolic acids (caffeic, ferrulic, proctocatechuic, coumaric and gallic acid) affected ³H-glutamine and/or ³H-deoxy-d-glucose (³H-DG) uptake. Gallic acid (100 µM) caused a 3-fold increase in ³H-DG uptake by AsPC-1 cells, associated with a 3.7-fold increase in lactic acid production. Gallic acid stimulated GLUT1-mediated ³H-DG uptake and increased the affinity of this transporter for ³H-DG. We further verified that gallic acid does not change GLUT1 transcription rates and cellular redox state and that its effect does not involve PI3K, mTOR and MAP kinases and is not associated with a proproliferative effect. Gallic acid also increased ³H-DG uptake by MCF-7 cells, although less potently. Further investigation is necessary to elucidate the cellular pathways involved in this effect of gallic acid.

Protocatechuic Acid Delays Postovulatory Oocyte Ageing in Mouse

SCOPE

Tea is a popular beverage worldwide and has many health functions. Protocatechuic acid (PCA) is an important bioactive component of tea and has benefit to health. In some cases, oocytes after ovulation may miss the optimal fertilization time and enter a postovulatory ageing process. Therefore, to investigate the role of PCA in delaying oocyte ageing is aimed.

METHODS AND RESULTS

Metaphase II (MII) oocytes aged in vitro are randomly divided into three groups: control, aged, and aged + PCA. PCA treatment (30 µM) reduces the fragmentation rate and the incidence of abnormal spindle morphology and chromosome misalignment of oocytes aged 24 h in vitro. The mitochondrial dysfunction of aged oocytes, such as decreased mitochondrial membrane potential and excessive accumulation of reactive oxygen (ROS), is also alleviated by PCA. PCA also delays apoptosis of aged oocytes, and improves the sperm binding capacity. Otherwise, aged oocytes treated with PCA have a higher fertilization rate and blastocyst rate compared with untreated aged oocytes in vitro.

CONCLUSION

PCA is an important bioactive ingredient of tea that improves aged oocyte quality, suggesting that PCA is available to improve the quality of aged oocytes in vitro.

Ethyl Protocatechuate Encapsulation in Solid Lipid Nanoparticles: Assessment of Pharmacotechnical Parameters and Preliminary In Vitro Evaluation for Colorectal Cancer Treatment

Colorectal cancer is one of the most diffused tumoral diseases. Since most medicaments employed for its treatment are debilitating, the use of naturally derived products, which can be effective against the mutated cells and, in addition, can reduce most inflammatory-related effects, could be extremely beneficial for the continued treatment of this disease. In this research, ethyl protocatechuate (PCAEE), a protocatechuic acid prodrug, was encapsulated in solid lipid nanoparticles (SLN) (prepared without and with Tween 80), which were characterized in terms of size, polydispersity index (PDI), zeta potential and thermotropic behavior. Encapsulation efficiency, release profile and interaction with a model of biomembrane were also assessed. The nanoparticles were tested in vitro on both healthy cells and on a model of tumoral cells. SLN prepared with Tween 80 was promising in terms of physicochemical properties (z-average of 190 nm, PDI 0.150 and zeta potential around -20 mV) and encapsulation efficiency (56%); they showed a desirable release profile, demonstrated an ability to penetrate and release the encapsulated PCAEE into a biomembrane model and were nontoxic on healthy cells. In addition, they caused a greater dose-dependent decrease in the viability of CaCo-2 cells than PCAEE alone. In conclusion, the formulation could be proposed for further studies to assess its suitability for the treatment of colorectal cancer.

Phytochemicals from Vanda bensonii and Their Bioactivities to Inhibit Growth and Metastasis of Non-Small Cell Lung Cancer Cells

The most prevalent lung cancer is non-small cell lung cancer (NSCLC). This lung cancer type often develops other organ-specific metastases that are critical burdens in the treatment process. Orchid species in the genus Vanda have shown their potential in folkloric medication of diverse diseases but not all its species have been investigated, and little is known about their anticancer activities against NSCLC. Here, we firstly profiled the specialized metabolites of Vanda bensonii and examined their capability to inhibit growth and metastasis of NSCLC using NCI-H460 cells as a study model. Four phytochemicals, including phloretic acid methyl ester (1), cymbinodin-A (2), ephemeranthoquinone B (3), and protocatechuic acid (4), were isolated from the whole plant methanolic extract of V. bensonii. The most distinguished cytotoxic effect on NCI-H460 cells was observed in the treatments with crude methanolic extract and compound 2 with the half maximal inhibitory concentrations of 40.39 μg mL−1 and 50.82 μM, respectively. At non-cytotoxic doses (10 μg mL−1 or 10 μM), only compound 1 could significantly limit NCI-H460 cell proliferation when treated for 48 h, while others excluding compound 4 showed significant reduction in cell proliferation after treating for 72 h. Compound 1 also significantly decreased the migration rate of NCI-H460 cells examined through a wound-healing assay. Additionally, the crude extract and compound 1 strongly affected survival and growth of NCI-H460 cells under anchorage-independent conditions. Our findings proved that natural products from V. bensonii could be promising candidates for the future pharmacotherapy of NSCLC.

Molecular insights and therapeutic implications of nanoengineered dietary polyphenols for targeting lung carcinoma: part I

Lung cancer is the second leading cause of cancer-related mortality globally, and non-small-cell lung cancer accounts for most lung cancer cases. Nanotechnology-based drug-delivery systems have exhibited immense potential in lung cancer therapy due to their fascinating physicochemical characteristics, in vivo stability, bioavailability, prolonged and targeted delivery, gastrointestinal absorption and therapeutic efficiency of their numerous chemotherapeutic agents. However, traditional chemotherapeutics have systemic toxicity issues; therefore, dietary polyphenols might potentially replace them in lung cancer treatment. Polyphenol-based targeted nanotherapeutics have demonstrated interaction with a multitude of protein targets and cellular signaling pathways that affect major cellular processes. This review summarizes the various molecular mechanisms and targeted therapeutic potentials of nanoengineered dietary polyphenols in the effective management of lung cancer.

P53-Related Anticancer Activities of Drimia calcarata Bulb Extracts Against Lung Cancer

Current lung cancer treatment strategies are ineffective, and lung cancer cases continue to soar; thus, novel anticancer drugs and targets are needed, and medicinal plants are promising to offer better alternatives. This study was aimed at analysing two p53 splice variants during the potential anticancer activities of Drimia calcarata (Dc) methanol and water extracts against different human lung cancer cell lines of varying p53 mutation status, and these included mutant H1573 and mutant H1437 and p53-wild type (A549) cells. The anticancer activities of the Dc extracts were assessed by establishing the cytotoxic effect and the apoptosis-inducing capacity of these extracts, using the MTT assay and Annexin V analysis, respectively, with the latter confirmed using fluorescence microscopy. The molecular mechanisms induced by these extracts were further evaluated using cell cycle analysis and RT-PCR. Both extracts demonstrated safety against noncancerous lung MRC-5 fibroblasts and exhibited significant anticancer potency (p < 0.001) against the H1437 (IC₅₀ values: 62.50 μg/ml methanol extract and 125 μg/ml WE), H1573 (IC₅₀ value: 125 μg/ml for both extracts) and A549 (IC₅₀ value: 500 μg/ml ME). The water extract had no effect on the viability of A549 cells. Treated H1437 cells underwent p53-dependent apoptosis and S-phase cell cycle arrest while H1573 treated cells underwent p53-independed apoptosis and G0/G1 cell cycle arrest through upregulation of p21 mRNA expression levels. The expression levels of STAT1, STAT3, STAT5A and STAT5B genes increased significantly (p < 0.001) following the treatment of H1573 cells with ME and WE. Treatment of H1437 cells with ME upregulated the STAT1, STAT3, STAT5A and STAT5B mRNAs. Our results indicate that the proliferative inhibitory effect of D. calcarata extracts on A549 and H1573 cells is correlated with the suppression of Bcl-2, STAT3 and STAT5B while that is not the case in H1437 cells. Thus, our results suggest that the dysregulation of anti-apoptotic molecules Bcl-2, STAT3, STAT5A and STAT5B in H1437 may play a role in cancer cell survival, which may consequently contribute to the development of p53-mutated non-small human lung cancer. Our results indicate that D. calcarata is a promising source of anticancer agents for the treatment of p53-mutant human non-small lung cancer cells than the p53-wild type human non-small lung cancer cells.

Protocatechuic acid protects mice from influenza A virus infection

Influenza A virus (IAV) H1N1 infection remains great challenge to public health and causes great burden over the world. Although there are anti-viral agents available, searching for effective agents to treat H1N1 infection is still in urgent because of the emergence of resistant strain. Protocatechuic acid (PCA) is a biological agent with multiple functions. In present study, we explored the effects of PCA on H1N1 infection. Mice infected with mouse adapted influenza strain A/Font Monmouth were administrated with PCA. The body weight change, mortality, lung index, viral titer, immune cell infiltration, and cytokine production in the lung were monitored. The activation of toll-like receptor 4 (TLR4) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) pathway was investigated. PCA treatment prevented H1N1 infection-induced mice body weight loss and death. PCA reduced the lung index, viral titer, infiltration of immune cells, and cytokine level in the lung, as well as suppressed H1N1-induced TLR4/NF-κB activation. PCA protects mice against H1N1 infection and could be a potential therapeutic agent to treat influenza.

In Vitro and In Vivo Studies of Anti-Lung Cancer Activity of Artemesia judaica L. Crude Extract Combined with LC-MS/MS Metabolic Profiling, Docking Simulation and HPLC-DAD Quantification

Artemisia judaica L. (Family: Asteraceae) exhibited antioxidant, anti-inflammatory, and antiapoptotic effects. The in vitro cytotoxic activity of A. judaica ethanolic extract was screened against a panel of cancer cell lines. The results revealed its cytotoxic activity against a lung cancer (A549) cell line with a promising IC50 of 14.2 μg/mL compared to doxorubicin as a standard. This was confirmed through the downregulation of antiapoptotic genes, the upregulation of proapoptotic genes, and the cell cycle arrest at the G2/M phase. Further in vivo study showed that a solid tumor mass was significantly reduced, with a tumor inhibition ratio of 54% relative to doxorubicin therapy in a Xenograft model. From a chemical point of view, various classes of natural products have been identified by liquid chromatography combined with tandem mass spectrometry (LC-MS/MS). The docking study of the detected metabolites approved their cytotoxic activity through their virtual binding affinity towards the cyclin-dependent kinase 2 (CDK-2) and epidermal growth factor receptor (EGFR) active sites. Finally, A. judaica is a fruitful source of polyphenols that are well-known for their antioxidant and cytotoxic activities. As such, the previously reported polyphenols with anti-lung cancer activity were quantified by high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD). Rutin, quercetin, kaempferol, and apigenin were detected at concentrations of 6 mg/gm, 0.4 mg/gm, 0.36 mg/gm, and 3.9 mg/gm of plant dry extract, respectively. It is worth noting that kaempferol and rutin are reported for the first time. Herein, A. judaica L. may serve as an adjuvant therapy or a promising source of leading structures in drug discovery for lung cancer treatment.

Protocatechuic Acid, a Simple Plant Secondary Metabolite, Induced Apoptosis by Promoting Oxidative Stress through HO-1 Downregulation and p21 Upregulation in Colon Cancer Cells

Gastrointestinal cancers, particularly colorectal cancer, are mainly influenced by the dietary factor. A diet rich in fruits and vegetables can help to reduce the incidence of colorectal cancer thanks to the phenolic compounds, which possess antimutagenic and anticarcinogenic properties. Polyphenols, alongside their well-known antioxidant properties, also show a pro-oxidative potential, which makes it possible to sensitize tumor cells to oxidative stress. HO-1 combined with antioxidant activity, when overexpressed in cancer cells, is involved in tumor progression, and its inhibition is considered a feasible therapeutic strategy in cancer treatment. In this study, the effects of protocatechuic acid (PCA) on the viability of colon cancer cells (CaCo-2), annexin V, LDH release, reactive oxygen species levels, total thiol content, HO-1, γ-glutamylcysteine synthetase, and p21 expression were evaluated. PCA induced, in a dose-dependent manner, a significantly reduced cell viability of CaCo-2 by oxidative/antioxidant imbalance. The phenolic acid induced modifications in levels of HO-1, non-proteic thiol groups, γ-glutamylcysteine synthetase, reactive oxygen species, and p21. PCA induced a pro-oxidant effect in cancer cells, and the in vitro pro-apoptotic effect on CaCo-2 cells is mediated by the modulation of redox balance and the inhibition of the HO-1 system that led to the activation of p21. Our results suggest that PCA may represent a useful tool in prevention and/or therapy of colon cancer.

Inhibiting effect of p-Coumaric acid on U87MG human glioblastoma cell growth

p-Coumaric acid (pCA) is a hydroxycinnamic acid derivative commonly found in many natural products that has been extensively studied for its anticancer activity in multiple cell lines. In this report we investigated the effects of this phytochemical as adjuvant therapy to treat glioblastoma, an infaust brain tumour characterized by the acquired or innate resistance to the conventional chemotherapy temozolomide (TMZ). U87Mg glioblastoma cell growth and viability was assessed by growth rate curves and MTT assay incubating cells with 0.5 and 1 mM pCA for 24 h, 48 h and 72 h. Cell cycle analysis, performed by flow cytometry, showed that pCA led the accumulation of GBM cells in G2/M phase. Western blot analysis shows that pCA induced CDK4 cyclin-dependent kinase reduction and p53 increase, followed by induction of the CDK inhibitor p21. Furthermore, pCA treatment mediated the activation of apoptosis and the inhibition of migration of U87Mg cells. Finally, the treatment of glioblastoma cells in vitro with pCA concomitantly with the TMZ revealed a synergistic effect between the natural substance and the chemotherapy. In conclusion, our results demonstrated that pCA acts influencing the cell viability and cell cycle of U87Mg cells by promoting cell cycle arrest in G2/M phase and apoptosis.

Blood-Spinal Cord Barrier in Spinal Cord Injury: A Review

The blood-spinal cord barrier (BSCB), a physical barrier between the blood and spinal cord parenchyma, prevents the toxins, blood cells, and pathogens from entering the spinal cord and maintains a tightly controlled chemical balance in the spinal environment, which is necessary for proper neural function. A BSCB disruption, however, plays an important role in primary and secondary injury processes related to spinal cord injury (SCI). After SCI, the structure of the BSCB is broken down, which leads directly to leakage of blood components. At the same time, the permeability of the BSCB is also increased. Repairing the disruption of the BSCB could alleviate the SCI pathology. We review the morphology and pathology of the BSCB and progression of therapeutic methods targeting BSCB in SCI.

Identification of Targets and Active Components of Yiqi SanJie Formula Against Lung Neoplasms Based on Network Pharmacology Analysis and Molecular Docking

Yiqi Sanjie formula (YQSJF) is mainly applied clinically for the treatment of lung neoplasms. The purpose of this study was to explore the pharmacodynamics of the active components of YQSJF and the mechanism of therapeutic effects in the treatment of lung neoplasm diseases based on network pharmacology. The network of component-target, target-pathway, and pathway-disease of YQSJF was constructed by using Cytoscape software. According to the screening result, 37 key components, 57 important targets, and 866 candidate pathways were obtained. The enrichment analysis results indicated that YQSJF might play a therapeutic role in lung cancer by regulating several signaling pathways, such as the PI3K-AKT, non-small cell lung cancer, small cell lung cancer, and apoptosis pathways. There were 53 intersection genes between YQSJF and the lung cancer gene, 52 common genes, and 11 key targets, including CASP8, CASP9, AR, ESR1, PTGS2, NOS3, PGR, TGFB1, PPARG, RELA, and NOS2, screened by using Protein-Protein Interaction (PPI) analysis. These could be the potential therapeutic targets of YQSJF against lung cancer. Enrichment analysis of the intersection gene pathways revealed 10 major functional pathways, including the VEGF, apoptosis, and IL-17 signaling pathways. The molecular docking results showed the potential regulating activity of kaempferol against AR, pelargonidin against PGR, and baicalein against both PTGS2 and AR. In conclusion, combinational network pharmacology analysis results indicated that YQSJF might present its efficacy of alleviating lung neoplasm symptoms through multiple targets in a synergetic way.

Combined Effects of Protocatechuic Acid and 5-Fluorouracil on p53 Gene Expression and Apoptosis in Gastric Adenocarcinoma Cells

Objectives

This study evaluated the combined effects of protocatechuic acid (PCA) and 5-fluorouracil (5-FU) on gastric adenocarcinoma (AGS) cells.

Materials and Methods

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, flow cytometry technique, real-time quantitative polymerase chain reaction, and Western blotting were used to investigate cytotoxic effects, colony formation, apoptosis, p53 gene expression, and Bcl-2 protein level in AGS cells treated with 5-FU and PCA.

Results

Our results demonstrated that PCA (500 μM) alone or in combination with 5-FU (10 μM) inhibited AGS cell proliferation, inhibited a colony formation, and increased apoptosis compared with untreated control cells. Moreover, the combined 5-FU/PCA exposure led to upregulation of p53 and downregulation of Bcl-2 protein when compared to the untreated control cells.

Conclusion

The results demonstrate that the combined 5-FU/PCA may promote antiproliferative and pro-apoptotic effects with the inhibition of colony formation in AGS cells. The mechanisms by which the combined 5-FU/PCA exposure exerts its effects are associated with upregulation of p53 gene expression and downregulation of Bcl-2 level. Therefore, the combination of 5-FU with PCA not only could be a promising approach to potentially reduce the dose requirements of 5-FU but also could promote apoptosis via p53 and Bcl-2 signaling pathways.

Identification of protocatechuic acid as a novel blocker of epithelial-to-mesenchymal transition in lung tumor cells

Protocatechuic acid (PA) is widely distributed and commonly occurring natural compound that can exert antioxidant, anti-inflammatory, as well as anti-cancer effects. Epithelial-to-mesenchymal transition (EMT) is important cellular process that can control tumor invasion and metastasis. Here, we investigated whether PA can modulate the EMT process in basal and transforming growth factorβ-induced A549 and H1299 cells. We found that PA suppressed expression of mesenchymal markers (Fibronectin, Vimentin, and N-cadherin), MMP-9, MMP-2, twist, and snail but stimulated the levels of epithelial markers (E-cadherin and Occludin). In addition, PA can affect TGFβ-induced expression of both mesenchymal and epithelial markers. Moreover, PA abrogated migratory and invasive potential of tumor cells by reversing the EMT process. Furthermore, we found that PA suppressed EMT process by abrogating the activation of PI3K/Akt/mTOR signaling cascade in lung cancer cells.

Inhibiting CDK6 Activity by Quercetin Is an Attractive Strategy for Cancer Therapy

Cyclin-dependent kinase 6 (CDK6) is a potential drug target that plays an important role in the progression of different types of cancers. We performed in silico and in vitro screening of different natural compounds and found that quercetin has a high binding affinity for the CDK6 and inhibits its activity with an IC50 = 5.89 μM. Molecular docking and a 200 ns whole atom simulation of the CDK6-quercetin complex provide insights into the binding mechanism and stability of the complex. Binding parameters ascertained by fluorescence and isothermal titration calorimetry studies revealed a binding constant in the range of 107 M-1 of quercetin to the CDK6. Thermodynamic parameters associated with the formation of the CDK6-quercetin complex suggested an electrostatic interaction-driven process. The cell-based protein expression studies in the breast (MCF-7) and lung (A549) cancer cells revealed that the treatment of quercetin decreases the expression of CDK6. Quercetin also decreases the viability and colony formation potential of selected cancer cells. Moreover, quercetin induces apoptosis, by decreasing the production of reactive oxygen species and CDK6 expression. Both in silico and in vitro studies highlight the significance of quercetin for the development of anticancer leads in terms of CDK6 inhibitors.

Continuous flow synthesis of lipophilic cations derived from benzoic acid as new cytotoxic chemical entities in human head and neck carcinoma cell lines

Continuous flow chemistry was used for the synthesis of a series of delocalized lipophilic triphenylphosphonium cations (DLCs) linked by means of an ester functional group to several hydroxylated benzoic acid derivatives and evaluated in terms of both reaction time and selectivity. The synthesized compounds showed cytotoxic activity and selectivity in head and neck tumor cell lines. The mechanism of action of the molecules involved a mitochondrial uncoupling effect and a decrease in both intracellular ATP production and apoptosis induction.

Co-culture of human alveolar epithelial (A549) and macrophage (THP-1) cells to study the potential toxicity of ambient PM2.5: a comparison of growth under ALI and submerged conditions

Fine particulate matter (PM_2.5) in the ambient atmosphere is strongly associated with detrimental health effects. However, these particles from various sources and regions are unlikely equally toxic. While animal studies are impractical for high-throughput toxicity testing, appropriate in vitro models are urgently needed. Co-culture of A549 and THP-1 macrophages grown at air-liquid interface (ALI) or under submerged conditions was exposed to same concentrations of ambient PM_2.5 to provide accurate comparisons between culture methods. Following 24-h incubation with PM_2.5 collected in Harbin in China, biological endpoints being investigated include cytotoxicity, reactive oxygen species (ROS) levels and pro-inflammatory mediators. The co-culture grown under submerged condition demonstrated a significant increase in ROS levels and all tested pro-inflammatory indicators [interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α] in mRNA expression and released protein levels. Similar but a declining response trend was observed using the same PM_2.5 incubation after grown at ALI. We further observed a significant increase of PM_2.5-induced phosphorylation of p38 MAPK and activation of NF-κB p65 in a dose-dependent trend for co-cultures grown under submerged condition. These results provide important implications that culture conditions (ALI versus submerged) can induce different extents of biological responses to ambient PM_2.5; the co-culture grown at ALI is less likely to produce false-positive results than submerged culture. Hence, culture conditions should be discussed when comparing in vitro methods used for high-throughput PM_2.5 toxicity assessment in future.

Increased Cytotoxic Efficacy of Protocatechuic Acid in A549 Human Lung Cancer Delivered via Hydrophobically Modified-Chitosan Nanoparticles As an Anticancer Modality

The growing incidence of global lung cancer cases against successful treatment modalities has increased the demand for the development of innovative strategies to complement conventional chemotherapy, radiation, and surgery. The substitution of chemotherapeutics by naturally occurring phenolic compounds has been touted as a promising research endeavor, as they sideline the side effects of current chemotherapy drugs. However, the therapeutic efficacy of these compounds is conventionally lower than that of chemotherapeutic agents due to their lower solubility and consequently poor intracellular uptake. Therefore, we report herein a hydrophobically modified chitosan nanoparticle (pCNP) system for the encapsulation of protocatechuic acid (PCA), a naturally occurring but poorly soluble phenolic compound, for increased efficacy and improved intracellular uptake in A549 lung cancer cells. The pCNP system was modified by the inclusion of a palmitoyl group and physico-chemically characterized to assess its particle size, Polydispersity Index (PDI) value, amine group quantification, functional group profiling, and morphological properties. The inclusion of hydrophobic palmitoyl in pCNP-PCA was found to increase the encapsulation of PCA by 54.5% compared to unmodified CNP-PCA samples whilst it only conferred a 23.4% larger particle size. The single-spherical like particles with uniformed dispersity pCNP-PCA exhibited IR bands, suggesting the successful incorporation of PCA within its core, and a hydrophobic layer was elucidated via electron micrographs. The cytotoxic efficacy was then assessed by using an MTT cytotoxicity assay towards A549 human lung cancer cell line and was compared with traditional chitosan nanoparticle system. Fascinatingly, a controlled release delivery and enhanced therapeutic efficacy were observed in pCNP-PCA compared to CNP, which is ascribed to lower IC50 values in the 72-h treatment in the pCNP system. Using the hydrophobic system, efficacy of PCA was significantly increased in 24-, 48-, and 72-h treatments compared to a single administration of the compound, and via the unmodified CNP system. Findings arising from this study exhibit the potential of using such modified nanoparticulate systems in increasing the efficacy of natural phenolic compounds by augmenting their delivery potential for better anti-cancer responses.

Targeting Multiple Signaling Pathways in Cancer: The Rutin Therapeutic Approach

Multiple dysregulated signaling pathways are implicated in the pathogenesis of cancer. The conventional therapies used in cancer prevention/treatment suffer from low efficacy, considerable toxicity, and high cost. Hence, the discovery and development of novel multi-targeted agents to attenuate the dysregulated signaling in cancer is of great importance. In recent decades, phytochemicals from dietary and medicinal plants have been successfully introduced as alternative anticancer agents due to their ability to modulate numerous oncogenic and oncosuppressive signaling pathways. Rutin (also known as rutoside, quercetin-3-O-rutinoside and sophorin) is an active plant-derived flavonoid that is widely distributed in various vegetables, fruits, and medicinal plants, including asparagus, buckwheat, apricots, apples, cherries, grapes, grapefruit, plums, oranges, and tea. Rutin has been shown to target various inflammatory, apoptotic, autophagic, and angiogenic signaling mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukins, light chain 3/Beclin, B cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein, caspases, and vascular endothelial growth factor. A comprehensive and critical analysis of the anticancer potential of rutin and associated molecular targets amongst various cancer types has not been performed previously. Accordingly, the purpose of this review is to present an up-to-date and critical evaluation of multiple cellular and molecular mechanisms through which the anticancer effects of rutin are known to be exerted. The current challenges and limitations as well as future directions of research are also discussed.

Mapping Pharmacological Network of Multi-Targeting Litchi Ingredients in Cancer Therapeutics

Considerable pharmacological studies have demonstrated that the extracts and ingredients from different parts (seeds, peels, pulps, and flowers) of Litchi exhibited anticancer effects by affecting the proliferation, apoptosis, autophagy, metastasis, chemotherapy and radiotherapy sensitivity, stemness, metabolism, angiogenesis, and immunity via multiple targeting. However, there is no systematical analysis on the interaction network of “multiple ingredients-multiple targets-multiple pathways” anticancer effects of Litchi. In this study, we summarized the confirmed anticancer ingredients and molecular targets of Litchi based on published articles and applied network pharmacology approach to explore the complex mechanisms underlying these effects from a perspective of system biology. The top ingredients, top targets, and top pathways of each anticancer function were identified using network pharmacology approach. Further intersecting analyses showed that Epigallocatechin gallate (EGCG), Gallic acid, Kaempferol, Luteolin, and Betulinic acid were the top ingredients which might be the key ingredients exerting anticancer function of Litchi, while BAX, BCL2, CASP3, and AKT1 were the top targets which might be the main targets underling the anticancer mechanisms of these top ingredients. These results provided references for further understanding and exploration of Litchi as therapeutics in cancer as well as the application of “Component Formula” based on Litchi’s effective ingredients.

Advanced glycation end products (AGEs), protein aggregation and their cross talk: new insight in tumorigenesis

Protein glycation and protein aggregation are two distinct phenomena being observed in cancer cells as factors promoting cancer cell viability. Protein aggregation is an abnormal interaction between proteins caused as a result of structural changes in them after any mutation or environmental assault. Protein aggregation is usually associated with neurodegenerative diseases like Alzheimer's and Parkinson's, but of late, research findings have shown its association with the development of different cancers like lung, breast and ovarian cancer. On the contrary, protein glycation is a cascade of irreversible nonenzymatic reaction of reducing sugar with the amino group of the protein resulting in the modification of protein structure and formation of advanced glycation end products (AGEs). These AGEs are reported to obstruct the normal function of proteins. Lately, it has been reported that protein aggregation occurs as a result of AGEs. This aggregation of protein promotes the transformation of healthy cells to neoplasia leading to tumorigenesis. In this review, we underline the current knowledge of protein aggregation and glycation along with the cross talk between the two, which may eventually lead to the development of cancer.

UHPLC-Q/Orbitrap/MS/MS fingerprinting and antitumoral effects of Prosopis strombulifera (LAM.) BENTH. queous extract on allograft colorectal and melanoma cancer models

The aqueous extract of the Argentinean native plant, Prosopis strombulifera (PsAE), presents cytotoxicity against human cancer cell lines by inducing cytostasis, necrosis and apoptosis; with diminution of clonogenic survival; without genotoxic effects nor oral animal toxicity. Until now, the chemical extract composition and its in vivo antitumoral properties remain unknown; these studies are the aim of the current work. The PsAE was characterized by chemical fingerprinting and the metabolome was identified by tandem UHPLC-PDA-HESI-Q-orbitrap® mass spectrometry. Colorectal tumors were induced by DMH administration and melanomas resulted from B16-F0 S.C. cells injection; then, animals were treated orally with PsEA. To correlate in vivo results with in vitro cytotoxicity, B16-F0 cell were cultured to determine: cell proliferation and viability by dye exclusion assays, MTT and CFSE dilution; cell cycle distribution by flow cytometry; and immunoblotting of p21^cip1, PCNA, cleaved caspase 3, cleaved PARP and TUBA1A. Based on UHPLC-OT-MS and PDA analysis, twenty-six compounds were identified, including: 5 simple organic acids, 4 phenolic acids, 4 procyanidins, 11 flavonoids, and 2 oxylipins. On C57BL6 mice, PsAE significantly increases the median survival on colorectal cancer and reduces the final volume and weight of melanomas. Over cultured cells, the treatment induce over-expression of p21, cytostasis by G2/M cell cycle arrest and apoptosis; while, on in vivo melanomas, treatment up-regulates p21 and slightly decreases PCNA. In conclusion, PsAE is composed by phenolic compounds which demonstrate cytotoxic and antitumoral properties when is orally administrated. Presented results support future research of PsAE as a potential phytomedicine for cancer treatment.

In Vitro Evaluation of Chemically Analyzed Hypericum Triquetrifolium Extract Efficacy in Apoptosis Induction and Cell Cycle Arrest of the HCT-116 Colon Cancer Cell Line

Naturally derived drugs and plant-based products are attractive commodities that are being explored for cancer treatment. This in vitro study aimed to investigate the role of Hypericum triquetrifolium (50% ethanol: 50% water) extract (HTE) treatment on apoptosis, cell cycle modulation, and cell cycle arrest in human colon cancer cell line (HCT-116). HTE induced cell death via an apoptotic process, as assayed by an Annexin V-Cy3 assay. Exposing HCT-116 cells to 0.064, 0.125, 0.25, and 0.5 mg/mL of HTE for 24 h led to 50 ± 9%, 71.6 ± 8%, 85 ± 5%, and 96 ± 1.5% apoptotic cells, respectively. HCT-116 cells treated with 0.25 and 0.5 mg/mL HTE for 3 h resulted in 38.9 ± 1.5% and 57.2 ± 3% cleavage of caspase-3-specific substrate, respectively. RT-PCR analysis revealed that the HTE extract had no effect on mRNA levels of Apaf-1 and NOXA. Moreover, the addition of 0.125 mg/mL and 0.25 mg/mL HTE for 24 h was clearly shown to attenuate the cell cycle progression machinery in HCT-116 cells. GC/MS analysis of the extract identified 21 phytochemicals that are known as apoptosis inducers and cell cycle arrest agents. All the compounds detected are novel in H. triquetrifolium. These results suggest that HTE-induced apoptosis of human colon cells is mediated primarily through the caspase-dependent pathway. Thus, HTE appears to be a potent therapeutic agent for colon cancer treatment.

Methyloleanolate Induces Apoptotic And Autophagic Cell Death Via Reactive Oxygen Species Generation And c-Jun N-terminal Kinase Phosphorylation

Background

To develop a potent anticancer agent similar to oleanolate, the underlying mechanisms of its derivative, methyloleanolate, in the apoptosis and autophagy of A549 and H1299 cells were elucidated.

Purpose

The aim of the present study was to investigate the effect of methyloleanolate in inducing apoptotic and autophagic cell death in cancer cells.

Materials and methods

Flow cytometric analysis with Annexin V/PI staining, Western blot analysis, and immunofluorescence analysis were conducted in A549 and H1299 cells.

Results

Methyloleanolate increased the fraction of Annexin V/PI apoptotic cells and activated caspase-8, caspase-3, and death receptor 5 (DR5) more than oleanolate in A549 and H1299 cells pretreated with pancaspase inhibitor z-VAD-fmk and DR5 depletion. Also, methyloleanolate induced autophagic features of microtubule-associated protein light chain 3 3BII (LC3BII) conversion and puncta in A549 and H1299 cells, along with autophagosomes and vacuoles. Methyloleanolate blocked autophagy flux for impaired autophagy and chloroquine (CQ)-enhanced microtubule-associated protein LC3BII accumulation and cytotoxicity in A549 and H1299 cells, although 3-methyladenine (3-MA) did not. Interestingly, LC3BII accumulation was detected only in methyloleanolate-treated autophagy-related gene 5 (ATG5)^+/+ mouse embryonic fibroblast (MEF) cells but not in ATG5 ^-/- MEF cells. Methyloleanolate reduced p-mTOR but activated p-c-Jun N-terminal kinases and reactive oxygen species production in A549 and H1299 cells. Conversely, n-acetyl-l-cysteine and SP600125 blocked apoptotic and autophagic cascades caused by methyloleanolate in A549 and H1299 cells.

Conclusion

Overall, the findings suggest that methyloleanolate induces apoptotic and autophagic cell death in non-small cell lung cancers via reactive oxygen species generation and c-Jun N-terminal kinase phosphorylation.

Development and Validation of a QuEChERS-LC-MS/MS Method for the Analysis of Phenolic Compounds in Rapeseed Oil

In recent years, the determination of phenolic compounds in vegetable oil has aroused broad attention because these compounds have beneficial effects on health. In this work, a novel method based on the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and LC-MS/MS was developed for the analysis of phenolic compounds. A total of 18 mL of acetonitrile, 3 mL of water, and 270 mg of C₁₈ sorbent were utilized in the optimized QuEChERS procedure. The LC-MS/MS analysis was performed in a C₁₈ column under gradient-elution conditions with eluent of acetonitrile and water with 0.1% acetic acid. The QuEChERS approach achieved decent extraction recoveries (75.32-103.93%) for most phenolic compounds. The QuEChERS-LC-MS/MS method was validated in terms of accuracy, precision, sensitivity, and linearity. The proposed method was further evaluated using different prepared rapeseed oils. The result demonstrated that QuEChERS-LC-MS/MS is a rapid and reliable method for determining phenolic compounds in rapeseed oils.

Protocatechuic acid improves functional recovery after spinal cord injury by attenuating blood-spinal cord barrier disruption and hemorrhage in rats

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries including inflammation. Inflammatory response is one of the major events resulting in apoptosis, scar formation and neuronal dysfunction after SCI. Here, we investigated whether protocatechuic acid (PCA), a natural phenolic compound, would attenuate BSCB disruption and hemorrhage, leading to functional improvement after SCI. After a moderate contusion injury at T9, PCA (50 mg/kg) was administrated via intraperitoneal injection immediately, 6 h, and 12 h after SCI, and the same dose of PCA once a day until 7 d after injury. Our data show that PCA inhibited apoptotic cell death of neurons and oligodendrocytes and improved functional recovery after injury. PCA also attenuated BSCB disruption and hemorrhage and reduced the infiltration of neutrophils and macrophages compared to vehicle control. Moreover, PCA inhibited the expression and activation of matrix metalloprotease-9, which is well known to disrupt BSCB after SCI. Furthermore, PCA treatment significantly inhibited the expression of sulfonylurea receptor 1 and transient receptor potential melastatin 4, which are known to mediate hemorrhage at an early stage after SCI. Consistent with these findings, the mRNA and protein expression of inflammatory mediators such as tumor necrosis factor alpha, interleukin 1 beta, cyclooxygenase-2, inducible nitric oxide synthase, and chemokines was significantly alleviated by PCA treatment. Thus, our results suggest that PCA improved functional recovery after SCI in part by inhibiting BSCB disruption and hemorrhage through the down-regulation of sulfonylurea receptor 1/transient receptor potential melastatin 4 and matrix metalloprotease-9.

Bioactive compounds from Cudrania tricuspidata: A natural anticancer source

The tumor is becoming a critical threat to our lives in these years. Searching for antitumor substances from natural products is a great interest of scientists. Cudrania tricuspidata (C. tricuspidata) is a regional plant containing 158 flavonoids and 99 xanthones, and others ingredients with favorable bioactivity. This review comprehensively analyzes the antitumor compounds from C. tricuspidata against different tumors, and 78 flavonoids plus xanthones are considered as underlying antineoplastic. Importantly, the structure of preylation groups is the primary source of antitumor activity among 45 flavonoids plus xanthones, which could be a direction of structural modification for a better antitumor ability. Additionally, the fruits are also preferable sources of antitumor compounds compared to the roots and barks due to the abundant isoflavones and sustainability. However, many studies only focused on the cells viability inhibition of the compounds, the underlying molecular mechanisms, and the intracellular targets remain ambiguous. In conclusion, C. tricuspidata has a great potential for anti-tumor prevention or therapy, but more attention should be paid to deeper research in vitro and in vivo models.

Inflammatory stimuli promote growth and invasion of pancreatic cancer cells through NF-κB pathway dependent repression of PP2Ac

Previous studies have indicated that inflammatory stimulation represses protein phosphatase 2A (PP2A), a well-known tumor suppressor. However, whether PP2A repression participates in pancreatic cancer progression has not been verified. We used lipopolysaccharide (LPS) and macrophage-conditioned medium (MCM) to establish in vitro inflammation models, and investigated whether inflammatory stimuli affect pancreatic cancer cell growth and invasion PP2A catalytic subunit (PP2Ac)-dependently. Via nude mouse models of orthotopic tumor xenografts and dibutyltin dichloride (DBTC)-induced chronic pancreatitis, we evaluated the effect of an inflammatory microenvironment on PP2Ac expression in vivo. We cloned the PP2Acα and PP2Acβ isoform promoters to investigate the PP2Ac transcriptional regulation mechanisms. MCM accelerated pancreatic cancer cell growth; MCM and LPS promoted cell invasion. DBTC promoted xenograft growth and metastasis, induced tumor-associated macrophage infiltration, promoted angiogenesis, activated the nuclear factor-κB (NF-κB) pathway, and repressed PP2Ac expression. In vitro, LPS and MCM downregulated PP2Ac mRNA and protein. PP2Acα overexpression attenuated JNK, ERK, PKC, and IKK phosphorylation, and impaired LPS/MCM-stimulated cell invasion and MCM-promoted cell growth. LPS and MCM activated the NF-κB pathway in vitro. LPS and MCM induced IKK and IκB phosphorylation, leading to p65/RelA nuclear translocation and transcriptional activation. Overexpression of the dominant negative forms of IKKα attenuated LPS and MCM downregulation of PP2Ac, suggesting inflammatory stimuli repress PP2Ac expression NF-κB pathway-dependently. Luciferase reporter gene assay verified that LPS and MCM downregulated PP2Ac transcription through an NF-κB-dependent pathway. Our study presents a new mechanism in inflammation-driven cancer progression through NF-κB pathway-dependent PP2Ac repression.

An overview on the role of dietary phenolics for the treatment of cancers

Plant derived phenolic compounds have been shown to inhibit the initiation and progression of cancers by modulating genes regulating key processes such as: (a) oncogenic transformation of normal cells; (b) growth and development of tumors; and (c) angiogenesis and metastasis. Recent studies focusing on identifying the molecular basis of plant phenolics-induced cancer cell death have demonstrated down-regulation of: (a) oncogenic survival kinases such as PI3K and Akt; (b) cell proliferation regulators that include Erk1/2, D-type Cyclins, and Cyclin Dependent Kinases (CDKs); (c) transcription factors such as NF-kβ, NRF2 and STATs; (d) histone deacetylases HDAC1 and HDAC2; and (e) angiogenic factors VEGF, FGFR1 and MIC-1. Furthermore, while inhibiting oncogenic proteins, the phenolic compounds elevate the expression of tumor suppressor proteins p53, PTEN, p21, and p27. In addition, plant phenolic compounds and the herbal extracts rich in phenolic compounds modulate the levels of reactive oxygen species (ROS) in cells thereby regulate cell proliferation, survival and apoptosis. Furthermore, recent studies have demonstrated that phenolic compounds undergo transformation in gut microbiota thereby acquire additional properties that promote their biological activities. In vitro observations, preclinical and epidemiological studies have shown the involvement of plant phenolic acids in retarding the cancer growth. However, to date, there is no clinical trial as such testing the role of plant phenolic compounds for inhibiting tumor growth in humans. More over, several variations in response to phenolic acid rich diets-mediated treatment among individuals have also been reported, raising concerns about whether phenolic acids could be used for treating cancers. Therefore, we have made an attempt to (a) address the key structural features of phenolic acids required for exhibiting potent anti-cancer activity; (b) review the reported findings about the mechanisms of action of phenolic compounds and their transformation by gut microbiota; and (c) update the toxicological aspects and anti-tumor properties of phenolic compounds and extracts containing phenolic compounds in animals.

Melatonin suppresses TPA-induced metastasis by downregulating matrix metalloproteinase-9 expression through JNK/SP-1 signaling in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), a disease common in the South-East Asian population, has high lymph node metastatic ability. Melatonin, an endogenously produced substance present in animals, plants, fungi, and bacteria, has oncostatic activity via several mechanisms. The molecular mechanisms involved in melatonin-mediated tumor inhibitory potential are not completely defined. Here, we show that melatonin treatment inhibits TPA-induced cell motility by regulating the matrix metalloproteinase-9 (MMP-9) expression in NPC. We also identified the signaling cascade through which melatonin inhibits MMP-9 expression; this involves melatonin regulating the binding activity of the transcription factor specificity protein-1 (SP-1)-DNA. Our mechanistic analysis further reveals that the c-Jun N-terminal kinase/mitogen-activated protein kinase pathway is involved in the melatonin-mediated tumor suppressor activity. Furthermore, the findings indicate a functional link between melatonin-mediated MMP-9 regulation and tumor suppressing ability and provide new insights into the role of melatonin-induced molecular and epigenetic regulation of tumor growth. Thus, we conclude that melatonin suppresses the motility of NPC by regulating TPA-induced MMP-9 gene expression via inhibiting SP-1-DNA binding ability. The results provide a functional link between melatonin-mediated SP-1 regulation and the antimetastatic actions of melatonin on nasopharyngeal carcinoma.

Advanced Glycation End-Products Enhance Lung Cancer Cell Invasion and Migration

Effects of carboxymethyllysine (CML) and pentosidine, two advanced glycation end-products (AGEs), upon invasion and migration in A549 and Calu-6 cells, two non-small cell lung cancer (NSCLC) cell lines were examined. CML or pentosidine at 1, 2, 4, 8 or 16 μmol/L were added into cells. Proliferation, invasion and migration were measured. CML or pentosidine at 4-16 μmol/L promoted invasion and migration in both cell lines, and increased the production of reactive oxygen species, tumor necrosis factor-α, interleukin-6 and transforming growth factor-β1. CML or pentosidine at 2-16 μmol/L up-regulated the protein expression of AGE receptor, p47(phox), intercellular adhesion molecule-1 and fibronectin in test NSCLC cells. Matrix metalloproteinase-2 protein expression in A549 and Calu-6 cells was increased by CML or pentosidine at 4-16 μmol/L. These two AGEs at 2-16 μmol/L enhanced nuclear factor κ-B (NF-κ B) p65 protein expression and p38 phosphorylation in A549 cells. However, CML or pentosidine at 4-16 μmol/L up-regulated NF-κB p65 and p-p38 protein expression in Calu-6 cells. These findings suggest that CML and pentosidine, by promoting the invasion, migration and production of associated factors, benefit NSCLC metastasis.

Obovatol Induces Apoptosis in Non-small Cell Lung Cancer Cells via C/EBP Homologous Protein Activation

Although obovatol, a phenolic compound from the bark of Magnolia obovata, was known to have antioxidant, neuroprotective, antiinflammatory, antithrombotic and antitumour effects, its underlying antitumour mechanism is poorly understood so far. Thus, in the present study, the antitumour molecular mechanism of obovatol was investigated in non-small cell lung cancer cells (NSCLCs). Obovatol exerted cytotoxicity in A549 and H460 NSCLCs, but not in BEAS-2B cells. Also, obovatol increased sub-G1 accumulation and early and late apoptotic portion in A549 and H460 NSCLCs. Consistently, obovatol cleaved PARP, activated caspase 9/3 and Bax and attenuated the expression of cyclin D1 in A549 and H460 NSCLCs. Interestingly, obovatol upregulated the expression of endoplasmic reticulum stress proteins such as C/EBP homologous protein (CHOP), IRE1α, ATF4 and p-elF2 in A549 and H460 NSCLCs. Conversely, depletion of CHOP blocked the apoptotic activity of obovatol to increase sub-G1 accumulation in A549 and H460 NSCLCs. Overall, our findings support scientific evidences that obovatol induces apoptosis via CHOP activation in A549 and H460 NSCLCs. Copyright © 2016 John Wiley & Sons, Ltd.

The Chemistry of Gut Microbial Metabolism of Polyphenols

Gut microbiota contribute to the metabolism of dietary polyphenols and affect the bioavailability of both the parent polyphenols and their metabolites. Although there is a large number of reports of specific polyphenol metabolites, relatively little is known regarding the chemistry and enzymology of the metabolic pathways utilized by specific microbial species and taxa, which is the focus of this review. Major classes of dietary polyphenols include monomeric and oligomeric catechins (proanthocyanidins), flavonols, flavanones, ellagitannins, and isoflavones. Gut microbial metabolism of representatives of these polyphenol classes can be classified as A- and C-ring cleavage (retro Claisen reactions), C-ring cleavage mediated by dioxygenases, dehydroxylations (decarboxylation or reduction reactions followed by release of H₂O molecules), and hydrogenations of alkene moieties in polyphenols, such as resveratrol, curcumin, and isoflavones (mediated by NADPH-dependent reductases). The qualitative and quantitative metabolic output of the gut microbiota depends to a large extent on the metabolic capacity of individual taxa, which emphasizes the need for assessment of functional analysis in conjunction with determinations of gut microbiota compositions.

Piperlongumine inhibits lung tumor growth via inhibition of nuclear factor kappa B signaling pathway

Piperlongumine has anti-cancer activity in numerous cancer cell lines via various signaling pathways. But there has been no study regarding the mechanisms of PL on the lung cancer yet. Thus, we evaluated the anti-cancer effects and possible mechanisms of PL on non-small cell lung cancer (NSCLC) cells in vivo and in vitro. Our findings showed that PL induced apoptotic cell death and suppressed the DNA binding activity of NF-κB in a concentration dependent manner (0-15 μM) in NSCLC cells. Docking model and pull down assay showed that PL directly binds to the DNA binding site of nuclear factor-κB (NF-κB) p50 subunit, and surface plasmon resonance (SPR) analysis showed that PL binds to p50 concentration-dependently. Moreover, co-treatment of PL with NF-κB inhibitor phenylarsine oxide (0.1 μM) or p50 siRNA (100 nM) augmented PL-induced inhibitory effect on cell growth and activation of Fas and DR4. Notably, co-treatment of PL with p50 mutant plasmid (C62S) partially abolished PL-induced cell growth inhibition and decreased the enhanced expression of Fas and DR4. In xenograft mice model, PL (2.5-5 mg/kg) suppressed tumor growth of NSCLC dose-dependently. Therefore, these results indicated that PL could inhibit lung cancer cell growth via inhibition of NF-κB signaling pathway in vitro and in vivo.

Suppression of the nuclear transporter-KPNβ1 expression inhibits tumor proliferation in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the malignant tumors and leads to the highly death in the solid tumors, but its mechanism remains unclear. KPNβ1 is one of the soluble nuclear transport receptors, has been reported to act as an important role in the occurrence and development of tumor, such as cervical cancer, head and neck and lung cancer. However, the expression mechanisms and physiological significance of KPNβ1 in HCC is still unclear.

AIM

The expression of KPNβ1 and its involvement in HCC was studied.

METHODS

The expression of KPNβ1 protein was measured by Western blot and immunohistochemistry in HCC. We analyzed the effects of growth and interference of KPNβ1 in the cell cycle process by CCK8 and flow cytometrical analysis.

RESULTS

KPNβ1 protein level was up-regulated in HCC tissue samples. The KPNβ1 expression was significantly associated with histological differentiation. The levels of KPNβ1 were significantly correlated with histological grade (P = 0.03), metastasis (P = 0.01), vein invasion (P = 0.04) and tumor size (P = 0.01) in HCC samples. Serum starvation assay proved that KPNβ1 was arrested in G1 phase and was gradually reduced by refeeding serum. Moreover, the knockdown of KPNβ1 induced cell proliferation arrest in HepG2 cell. Western blot analyses showed that KPNβ1 was correlated with NF-кB signaling pathway.

CONCLUSIONS

Our datum showed that KPNβ1 expression was up-regulated in HCC tissue samples and increasing HCC cells growth and the KPNβ1 expression was associated with poor survival. KPNβ1 may take part in the pathogenesis of hepatocellular carcinoma via NF-кB signaling pathway and serve as an independent prognostic indicator and a novel therapeutic target for HCC.