Piceatannol Enhances the Antitumor Efficacy of Gemcitabine in Human A549 Non-Small Cell Lung Cancer Cells

Exploring the therapeutic potential of naturally occurring piceatannol in non-communicable diseases

Piceatannol is a naturally occurring hydroxylated resveratrol analogue that can be found in a variety of fruits and vegetables. It has been documented to have a wide range of beneficial effects, including anti-inflammatory, antioxidant, anti-aging, anti-allergic, antidiabetic, neuroprotective, cardioprotective, and chemopreventive properties. Piceatannol has significantly higher antioxidant activity than resveratrol. Piceatannol has been shown in preclinical studies to have the ability to inhibit or reduce the growth of cancers in various organs such as the brain, breast, lung, colon, cervical, liver, prostate, and skin. However, the bioavailability of Piceatannol is comparatively lower than resveratrol and other stilbenes. Several approaches have been reported in recent years to enhance its bioavailability and biological activity, and clinical trials are required to validate these findings. This review focuses on several aspects of natural stilbene Piceatannol, its chemistry, and its mechanism of action, and its promising therapeutic potential for the prevention and treatment of a wide variety of complex human diseases.

Potential of bacteriophage therapy in managing Staphylococcus aureus infections during chemotherapy for lung cancer patients

Respiratory Staphylococcus aureus infection represents a common complication in lung cancer patients, which is characterized with progressively and recurrently intratumor invasion. Although bacteriophages are widely reported as an effective bioweapon for managing bacterial infections, its applicability in handling infectious complications during cancer chemotherapy remains unknown. In this work, we hypothesized cancer chemotherapeutics would influence the efficacy of bacteriophages. To verify this end, interactions between four anticancer drugs (Gemcitabine, Doxorubicin, Cisplatin, and Irinotecan) with phage K were investigated, where Cisplatin directly reduced phage titers while Gemcitabine and Doxorubicin partially inhibited its propagation. The antibacterial efficacy of drug-phage K combinations was tested in a S. aureus infected cancer cell model. Doxorubicin enhanced the antibacterial capacity of phage K, destroying 22-folds of cell-associated bacteria than that of phage K alone use. Also, S. aureus migration was remarkably reduced by Doxorubicin. Overall, our data suggested that Doxorubicin had synergistic effects with phage K in combating S. aureus intracellular infection and migration. This work may broaden the options of indication for phage clinical transformation and also provide reference for the adjunctive application of chemo drugs in intracellular infection management.

Arginase: An emerging and promising therapeutic target for cancer treatment

Arginase is a key hydrolase in the urea cycle that hydrolyses L-arginine to urea and L-ornithine. Increasing number of studies in recent years demonstrate that two mammalian arginase isoforms, arginase 1 (ARG1) and arginase 2 (ARG2), were aberrantly upregulated in various types of cancers, and played crucial roles in the regulation of tumor growth and metastasis through various mechanisms such as regulating L-arginine metabolism, influencing tumor immune microenvironment, etc. Thus, arginase receives increasing focus as an attractive target for cancer therapy. In this review, we provide a comprehensive overview of the physiological and biological roles of arginase in a variety of cancers, and shed light on the underlying mechanisms of arginase mediating cancer cells growth and development, as well as summarize the recent clinical research advances of targeting arginase for cancer therapy.

Combination treatment of gemcitabine and sorafenib exerts a synergistic inhibitory effect on non-small cell lung cancer in vitro and in vivo via the epithelial-to-mesenchymal transition process

Standard chemotherapy is commonly used in clinical practice for the treatment of non-small cell lung cancer (NSCLC). However, its therapeutic efficacy remains low. Combination therapy for cancer treatment has attracted attention in recent years. The present study aimed to investigate the antitumor effect of the combination treatment with gemcitabine and sorafenib on NSCLC in vitro and in vivo, and to determine its underlying molecular mechanisms. The anti-NSCLC effects of combination therapy were analyzed by flow cytometry analysis, MTT, western blotting, reverse transcription-quantitative PCR, wound healing and Transwell invasion assays. A549 cells subjected to combination treatment with gemcitabine and sorafenib demonstrated a more irregular cellular morphology and lower cell viability compared with the monotherapy groups. Combination of gemcitabine and sorafenib significantly induced cell cycle arrest and apoptosis in A549 cells. Additionally, combination therapy was demonstrated to restrain the migration and invasion of tumor cells by suppressing epithelial-to-mesenchymal transition (EMT) of A549 cells. In vivo analyses confirmed that co-treatment with gemcitabine and sorafenib decreased NSCLC tumor growth and tumor weight in nude mice. Taken together, the results of the present study suggested that combination treatment with gemcitabine and sorafenib exerted a synergistic inhibitory effect on NSCLC in vitro and in vivo via the EMT process.

Alantolactone enhances gemcitabine sensitivity of lung cancer cells through the reactive oxygen species-mediated endoplasmic reticulum stress and Akt/GSK3β pathway

Lung cancer is one of the leading causes of cancer-associated mortality in China and globally. Gemcitabine (GEM), as a first-line therapeutic drug, has been used to treat lung cancer, but GEM resistance poses a major limitation on the efficacy of GEM chemotherapy. Alantolactone (ALT), a sesquiterpene lactone compound isolated from Inula helenium, has been identified to exert anticancer activity in various types of cancer, including breast, pancreatic, lung squamous and colorectal cancer. However, the underlying mechanisms of the anticancer activity of ALT in lung cancer remain to be fully elucidated. The present study aimed to determine whether ALT enhances the anticancer efficacy of GEM in lung cancer cells and investigated the underlying mechanisms. The cell viability was assessed with a Cell Counting Kit-8 assay. The cell cycle, apoptosis and the level of reactive oxygen species (ROS) were assessed by flow cytometry, and the expression of cell cycle-associated and apoptosis-associated proteins were determined by western blot analysis. The results demonstrated that ALT inhibited cell growth and induced S-phase arrest and cell apoptosis in A549 and NCI-H520 cells. Furthermore, ALT increased the level of ROS, inhibited the Akt/glycogen synthase kinase (GSK)3β pathway and induced endoplasmic reticulum (ER) stress in A549 and NCI-H520 cells. Additionally, ALT treatment sensitized lung cancer cells to GEM. Analysis of the molecular mechanisms further revealed that ALT enhanced the anticancer effects of GEM via ROS-mediated activation of the Akt/GSK3β and ER stress pathways. In conclusion, combined treatment with ALT and GEM may have potential as a clinical strategy for lung cancer treatment.

Light-Cross-linked Enediyne Small-Molecule Micelle-Based Drug-Delivery System

Light-cross-linked small-molecule micelles with enediyne units are designed for developing efficient drug-delivery systems. Gemcitabine (GEM) is chosen as a model hydrophilic drug and tethered with a maleimide-based enediyne (EDY) as a hydrophobic tail in the preparation of amphiphilic EDY-GEM. The stable micellar particles are obtained by cross-linking the enediyne moieties via photoinduced Bergman cyclization polymerization in aqueous media. The light-cross-linked spherical micelles with a size of 80 nm are characterized with dynamic light scattering and electron microscopy, showing robust micellar stability, bright fluorescent emission due to their intrinsic conjugated structure, and potential passive tumor-targeting ability through the enhanced permeability and retention effect. The drug-loaded micelles, as an example of light-cross-linked small-molecule micelle-based drug-delivery system, exhibit high drug-loading contents (50%) and greatly improved cytotoxicity toward A549 cells (decreasing the IC₅₀ value of Gemcitabine by 10 times), thanks to the greatly increased cellular uptake of the drug-loaded micelles as confirmed by confocal laser scanning microscopy. The light-cross-linked enediyne-based small-molecule micelles system therefore provides a simple yet efficient drug-delivery platform for cancer chemotherapy.

Oligostilbenoids in Vitis vinifera L. Pinot Noir grape cane extract: Isolation, characterization, in vitro antioxidant capacity and anti-proliferative effect on cancer cells

The following oligostilbenoids were isolated from extracts of Vitis vinifera L. Pinot Noir grape canes produced at a pilot-plant scale: (E)-ε-viniferin, (E)-resveratrol, (E)-piceatannol, ampelopsin A, vitisin B, pallidol, (E)-δ-viniferin, (E)-ω-viniferin, (E)-trans-cis-miyabenol C, isorhapontigenin, scirpusin A, and a new isomer named isoscirpusin A. The antioxidant capacity of the isolated stilbenoids was studied by three different assays, and their 50% inhibition concentration (IC₅₀) against cancer cells was determined by MTT reduction assay. Besides (E)-resveratrol, stilbenoids have outstanding antioxidant capacity in the ORAC-FL assay. The strongest antiproliferative effect was observed for (E)-piceatannol and ampelopsin A against the bladder cancer cell line J82. (E)-Piceatannol has inhibitory effect on human lung cancer SK-MES-1 cells. Moreover, the whole extract has antiproliferative effect on all tested cell lines. In conclusion, beside (E)-resveratrol, grape cane extract contains oligostilbenoids with potential health benefits. This underexploited viticultural residue has the potential to produce valuable phytochemicals or ingredients in functional foods.

Piceatannol induced apoptosis through up-regulation of microRNA-181a in melanoma cells

Background

Melanoma took top position among the lethal cancers and, despite there have been some great attempts made to increase the natural life of patients with metastatic disease, long-lasting and complete remissions are few. Piceatannol, owns the similar function as resveratrol, has been defined as an anti-cancer agent playing important role in inhibition of proliferation, migration and metastasis in various cancer. Thus, we aim to investigate the anti-cancer effect and mechanisms of piceatannol in melanoma cells.

Methods

Melanoma cell lines WM266-4 and A2058 were treated either with or without piceatannol. Cell viability and cell apoptosis were assessed by using MTT and Annexin V/PI assay, respectively. Cells were transfected with specific miRNA using Lipfectamine 2000. miRNA bingding ability to 3'-UTR region within specific gene was assed by firefly luciferase analysis. Gene and protein expression was eveluated by qRT-PCR and western blot analysis, respectively.

Results

Our study showed that piceatannol inhibited WM266-4 and A2058 cells growth and induced apoptosis. Totally, 16 differentially expressed miRNAs were screened out including 8 up-regulated and 8 down-regulated miRNAs. Expression level of miR-181a is significantly higher in piceatannol-treated cells than normal control and is lower in melanoma cancer tissues than its adjacent normal tissues. Bcl-2 is a target gene of miR-181a. Moreover, silencing of miR-181a reverses the decrease of cell viability induced by piceatannol in WM266-4 and A2058 cells. Taken together, present study uncovered the ability of piceatannol to repress melanoma cell growth and clarified the contribution of miR-181a in the anticancer role of piceatannol.

Conclusion

The present study proposes that piceatannol can be taken into account to be a hopeful anticancer agent for melanoma.

Trichosanthin enhances the antitumor effect of gemcitabine in non-small cell lung cancer via inhibition of the PI3K/AKT pathway

Gemcitabine (GEMZ) is the first-line therapy used against non-small cell lung cancer (NSCLC), and studies have focused on investigating the potential effects of agents combined with GEMZ to enhance the anticancer efficacy in NSCLC. Previous studies have reported that trichosanthin (TCS) has various physiological and pharmacological effects, including anti-human influenza virus enzymes, inhibition of protein synthesis and antitumor activity. The purpose of the present study was to investigate if TCS enhanced the antitumor effects of GEMZ in NSCLC. MTT assay demonstrated that TCS significantly enhanced the cytotoxic effect of GEMZ (P>0.05). Furthermore, a propidium iodide/Αnnexin V staining assay revealed that TCS exerted its pharmacological effect by increasing the apoptotic population. In addition, western blot analysis demonstrated that the combination treatment of TCS with GEMZ further decreased the expression level of phosphoinositide 3-kinase (PI3K) and AKT via regulating the expression of insulin growth factor. The results of the present study demonstrated that TCS enhanced the cytotoxic and apoptotic effects of GEMZ in A549 cells via regulating the PI3K/AKT pathway. In conclusion, these observations may provide a potential rational basis for a combination strategy for chemotherapy treatment of NSCLC.

Therapeutic Potential and Molecular Targets of Piceatannol in Chronic Diseases

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene; PIC) is a naturally occurring stilbene present in diverse plant sources. PIC is a hydroxylated analog of resveratrol and produced from resveratrol by microsomal cytochrome P450 1A11/2 and 1B1 activities. Like resveratrol, PIC has a broad spectrum of health beneficial effects, many of which are attributable to its antioxidative and anti-inflammatory activities. PIC exerts anticarcinogenic effects by targeting specific proteins involved in regulating cancer cell proliferation, survival/death, invasion, metastasis, angiogenesis, etc. in tumor microenvironment. PIC also has other health promoting and disease preventing functions, such as anti-obese, antidiabetic, neuroptotective, cardioprotective, anti-allergic, anti-aging properties. This review outlines the principal biological activities of PIC and underlying mechanisms with special focus on intracellular signaling molecules/pathways involved.

Resveratrol and capsaicin used together as food complements reduce tumor growth and rescue full efficiency of low dose gemcitabine in a pancreatic cancer model

Pancreatic adenocarcinoma, highly resistant to all current anti-cancer treatments, necessitates new approaches promoting cell death. We hypothesized that combined actions of several Bioactive Food Components (BFCs) might provide specific lethal effect towards tumor cells, sparing healthy cells. Human tumor pancreatic cell lines were tested in vitro for sensitivity to resveratrol, capsaicin, piceatannol, and sulforaphane cytotoxic effects. Combination of two or three components showed striking synergetic effect with gemcitabine in vitro. Each BFC used alone did not affect pancreatic tumor growth in a preclinical in vivo model, whereas couples of BFCs had anti-tumor activity. In addition, tumor toxicity was similar using gemcitabine alone or a combination of BFCs and two thirds of gemcitabine dose. Moreover, BFCs enhanced fibrotic response as compared to gemcitabine treatment alone. Reactive oxygen species (ROS) and apoptosis increases were observed, while cell cycle was very mildly affected. This study raises the possibility to use BFCs as beneficial food complements in the therapy of pancreatic adenocarcinoma, especially for patients unable to receive full doses of chemotherapy.