In Vitro Cytotoxic Effect of Aqueous Extracts from Leaves and Rhizomes of the Seagrass Posidonia oceanica (L.) Delile on HepG2 Liver Cancer Cells: Focus on Autophagy and Apoptosis

Abstract

Aqueous extracts from Posidonia oceanica’s green and brown (beached) leaves and rhizomes were prepared, submitted to phenolic compound and proteomic analysis, and examined for their potential cytotoxic effect on HepG2 liver cancer cells in culture. The chosen endpoints related to survival and death were cell viability and locomotory behavior, cell-cycle analysis, apoptosis and autophagy, mitochondrial membrane polarization, and cell redox state. Here, we show that 24 h exposure to both green-leaf- and rhizome-derived extracts decreased tumor cell number in a dose–response manner, with a mean half maximal inhibitory concentration (IC50) estimated at 83 and 11.5 μg of dry extract/mL, respectively. Exposure to the IC50 of the extracts appeared to inhibit cell motility and long-term cell replicating capacity, with a more pronounced effect exerted by the rhizome-derived preparation. The underlying death-promoting mechanisms identified involved the down-regulation of autophagy, the onset of apoptosis, the decrease in the generation of reactive oxygen species, and the dissipation of mitochondrial transmembrane potential, although, at the molecular level, the two extracts appeared to elicit partially differentiating effects, conceivably due to their diverse composition. In conclusion, P. oceanica extracts merit further investigation to develop novel promising prevention and/or treatment agents, as well as beneficial supplements for the formulation of functional foods and food-packaging material with antioxidant and anticancer properties.

Modulation of Glucose Consumption and Uptake in HepG2 Cells by Aqueous Extracts from the Coelomic Fluid of the Edible Holothuria tubulosa Sea Cucumber

“…The analysis of gene expression was performed through conventional and qRT-PCR [ 30 ]. Essentially, the total RNAs from control and treated cells were isolated using the PureLink RNA Mini kit (ThermoFisher) performing the on-column DNase treatment using the PureLink DNase set (ThermoFisher), as recommended by the manufacturer.…”

“…The quantitative analysis of the bands, when performed, was carried out with the ImageJ software with the normalization set to ACTB band intensity, which was used as the internal control. The differential expression of GLUT2 , GLUT4 , and HNF1A genes was further checked through the SYBR-Green-based qRT-PCR using the SYBR-Green qPCR MasterMix (MedChem Express, Monmouth Junction, NJ, USA) in an Applied Biosystems 7500 Real-Time PCR system, as previously reported by Abruscato et al [ 30 ]. The specificity of the amplification was checked by real-time PCR melting analysis, and the 2 −ΔΔCt method was used to quantitate the samples, as described in the Applied Biosystems Use Bulletin N.2 (P/N 4303859).…”

“…The Western blot analysis was performed as described elsewhere [ 30 ]. Essentially, control and treated HepG2 cells were collected and lysed in a buffer containing 7 M Urea, 2% CHAPS, and 10 mM DTT, supplemented with a protease inhibitor cocktail (Sigma).…”

Natural Anticancer Peptides from Marine Animal Species: Evidence from In Vitro Cell Model Systems

“…These natural metabolites, whose chemical communication ability encompasses different taxonomic lineages and even kingdoms, have found broad use in various applications, such as healthcare management, biomaterial manufacturing and environmental remediation, and, due to their peculiar chemical structures and properties, also in the development of new classes of molecules through the design of analogs with greater bioavailability and efficacy and less toxicity. To cite a few examples, this is the case for extracts, or isolated primary and secondary metabolites, obtained from marine vertebrates and invertebrates and seaweeds, which have shown anticancer, anti-angiogenic, anti-inflammatory and wound healing/skin regeneration abilities [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Moreover, the processing of by-products from marine animals and plants has also granted a number of beneficial properties due to their abundance in polyunsaturated fatty acids, amino acids, chitosan, carotenoids and polyphenols, among others [ 20 , 21 ].…”