Encapsulated Carbenoxolone Reduces Lung Metastases

Anoikis-Associated Lung Cancer Metastasis: Mechanisms and Therapies

Simple Summary

Anoikis is a programmed cell death process resulting from the loss of interaction between cells and the extracellular matrix. Therefore, it is necessary to overcome anoikis when tumor cells acquire metastatic potential. In lung cancer, the composition of the extracellular matrix, cell adhesion-related membrane proteins, cytoskeletal regulators, and epithelial–mesenchymal transition are involved in the process of anoikis, and the initiation of apoptosis signals is a critical step in anoikis. Inversely, activation of growth signals counteracts anoikis. This review summarizes the regulators of lung cancer-related anoikis and explores potential drug applications targeting anoikis.

Abstract

Tumor metastasis occurs in lung cancer, resulting in tumor progression and therapy failure. Anoikis is a mechanism of apoptosis that combats tumor metastasis; it inhibits the escape of tumor cells from the native extracellular matrix to other organs. Deciphering the regulators and mechanisms of anoikis in cancer metastasis is urgently needed to treat lung cancer. Several natural and synthetic products exhibit the pro-anoikis potential in lung cancer cells and in vivo models. These products include artonin E, imperatorin, oroxylin A, lupalbigenin, sulforaphane, renieramycin M, avicequinone B, and carbenoxolone. This review summarizes the current understanding of the molecular mechanisms of anoikis regulation and relevant regulators involved in lung cancer metastasis and discusses the therapeutic potential of targeting anoikis in the treatment of lung cancer metastasis.

Newly synthesized methionine aminopeptidase 2 inhibitor hinders tumor growth

Methionine aminopeptidase 2 (MetAp2) inhibition has been recognized as a promising approach for suppressing angiogenesis and cancer progression. Small molecule fumagillol derivatives with adamantane side groups were synthesized and evaluated for MetAp2 inhibition activity, and a lead molecule with superior abilities to inhibit the enzymatic activity of MetAp2 was identified. The compound, referred to as AD-3281, effectively suppressed proliferation of cancer and endothelial cells and impaired tube formation of endothelial cells in vitro. When administered systemically, AD-3281 was well tolerated and led to a significant suppression of human melanoma and mammary tumor xenografts grown in mice. The activity in vivo was associated with reduced angiogenesis and tumor proliferation as detected histologically. In order to develop a formulation that can solubilize AD-3281 with a minimal content of organic solvents, biodegradable nanoparticles comprised of poly-lactic-co-glycolic acid (PLGA) were fabricated and characterized. Compared with the free compound, AD-3281-loaded nanoparticles showed an advantageous cellular availability and uptake, leading to higher activity in cells and better transport in three-dimensional (3D) cultures. Taken together, we introduce a novel MetAp2 inhibitor with high anti-cancer activity and a stable nano-formulation with a high potential for future clinical translation.

In silico and experimental studies of bovine serum albumin-encapsulated carbenoxolone nanoparticles with reduced cytotoxicity

Carbenoxolone (CBX) is a semi-synthetic plant derivative with pleiotropic pharmacological properties like anti-microbial and anti-inflammatory activities. Though approved for treatment of gastric ulcers, its use is limited due to adverse effects such as cytotoxicity. Bovine serum albumin (BSA) is a natural, non-toxic protein with high water-solubility and low immunogenicity, and is widely used as a nanocarrier for targeted drug delivery. In the present study, controlled release BSA-CBX nanoparticles (NPs) were synthesized by desolvation method to reduce drug cytotoxicity. These NPs showed desirable physicochemical properties such as particle size (∼240 nm), polydispersity index (0.08), zeta potential (-7.12 mV), drug encapsulation efficiency (72 %), and were stable for at least 3 months at room temperature. The drug was released from the BSA-CBX NPs in a biphasic manner in vitro following non-fickian diffusion. Computational analysis determined that the binding between BSA and CBX occurred through van der Waals forces, hydrophobic interactions, and hydrogen bonds with 93 % steric stability. Further, the cytotoxic assays demonstrated ∼1.8-4.9-fold reduction in cytotoxicity using three human cell lines (A549, MCF-7, and U-87). Subsequently, this novel CBX formulation with BSA as an efficient carrier can potentially be used for diverse biomedical applications.

Nanoencapsulation of Pomegranate Extract to Increase Stability and Potential Dermatological Protection

Pomegranate extract (PG-E) has been reported to exert a protective effect on the skin due to its antioxidant activity. Ingredients rich in phenolic compounds are unstable in extract solutions, and, therefore, the use of a suitable nanosystem to encapsulate this type of extract could be necessary in different biotechnological applications. Thus, we investigated the capacity of Brassica oleracea L. (cauliflower) inflorescence vesicles (CI-vesicles) to encapsulate PG-E and determined the stability and the antioxidant capacity of the system over time. In addition, the protective effect against UV radiation and heavy metals in HaCaT cells was also tested. The CI-vesicles had an entrapment efficiency of around 50%, and accelerated stability tests did not show significant changes in the parameters tested. The results for the HaCaT cells showed the non-cytotoxicity of the CI-vesicles containing PG-E and their protection against heavy metals (lead acetate and mercuric chloride) and UV-B radiation through a reduction of oxidative stress. The reduction of the percentage of deleted mtDNA (mtDNA4977, "common deletion") in UV-treated HaCaT cells due to the presence of CI-vesicles containing PG-E indicated the mechanism of protection. Therefore, the effects of CI-vesicles loaded with PG-E against oxidative stress support their utilization as natural cosmeceuticals to protect skin health against external damage from environmental pollution and UV radiation.

Liquorice for pain?

Liquorice has a long history of use in traditional Chinese, Ayurvedic and herbal medicine. The liquorice plant contains numerous bioactive compounds, including triterpenes, flavonoids and secondary metabolites, with glycyrrhizin being the main active compound. Liquorice constituents have been found to have anti-inflammatory, antioxidant, antiviral, anticancer, hepatoprotective and neuroprotective properties. In addition, they appear to have antidepressant actions and effects on morphine tolerance. Glycyrrhizin, its metabolite glycyrrhetic (glycyrrhetinic) acid and other liquorice-derived compounds such as isoflavonoids and trans-chalcones, exert potent anti-inflammatory effects via a wide range of mechanisms including high mobility group box 1 protein (HMGB1) inhibition, gap junction blockade and α_2A-adrenoceptor antagonism. These properties, together with an increasing body of preclinical studies and a long history of use in herbal medicine, suggest that liquorice constituents may be useful for pain management. Glycyrrhizin is used widely in the confectionary, food and tobacco industries, but has documented adverse effects that may limit clinical use. Whether liquorice plant-derived compounds represent a novel class of analgesics is yet to be established. Having a host of bioactive compounds with a broad range of mechanisms of effect, liquorice is a plant that, in the future, may give rise to new therapies for pain.

Controlled release and enhanced biological activity of chitosan-fabricated carbenoxolone nanoparticles

Nanotechnology based antimicrobial drugs are developed to enhance their properties to combat multidrug resistant microbes. Carbenoxolone (CBX) is a semi-synthetic derivate of a natural substance from the licorice plant, with anti- (inflammatory, fungal, viral, microbial, fibrotic and cancer) properties. Though used to treat gastric ulcers, its low aqueous stability, low bioavailability and toxicity limited the drug's utility. To enhance its antimicrobial activity and reduce cytotoxicity, a controlled release nanoformulation was developed using natural biodegradable polymer chitosan (CS) as a carrier which is biocompatible, nontoxic with placid antimicrobial property. UV-visible spectroscopy, electron microscopy, and Fourier transform infrared spectroscopy were used for characterization of the resultant CS-CBX nanoparticles (NPs). They were spherical with uniform dispersion, ~200 nm in size with surface charge of +18.6 mV and drug encapsulation of >80%. Drug release kinetics exhibited a controlled release of 86% over 36 h following zero order kinetics. The anti-microbial activity against common pathogenic Gram -ve and +ve bacteria and yeast increased ~2-fold with a concomitant 4-fold reduction in cytotoxicity assessed using human lung adeno carcinoma (A549) cells. This study demonstrates the affirmative aspects of CS-CBX NPs as a promising antibacterial agent and may facilitate repositioning of the drug for diverse applications.