Antitumour Potential of Gigartina pistillata Carrageenans against Colorectal Cancer Stem Cell-Enriched Tumourspheres

Abstract

Gigartina pistillata is a red seaweed common in Figueira da Foz, Portugal. Here, the antitumour potential of G. pistillata carrageenan, with a known variable of the life cycle, the female gametophyte (FG) and tetrasporophyte (T) was evaluated against colorectal cancer stem cell (CSC) -enriched tumourspheres. FTIR-ATR analysis of G. pistillata carrageenan extracts indicated differences between life cycle phases, being FG a κ/ι hybrid carrageenan and T a ʎ/ξ hybrid. Both carrageenan extracts presented IC50 values inferior to 1 μg/mL in HT29-derived CSC-enriched tumourspheres, as well as reduced tumoursphere area. The two extracts were also effective at reducing cellular viability in SW620- and SW480-derived tumourspheres. These results indicate that carrageenans extracted from two G. pistillata life cycle phases have antitumour potential against colorectal cancer stem-like cells, specially the T carrageenan.

A Comprehensive Review of the Nutraceutical and Therapeutic Applications of Red Seaweeds (Rhodophyta)

“…It has been proven that carrageenans have anticoagulant and antithrombotic properties, with λ-carrageenan showing higher anticoagulant potential than κ-carrageenan [157]. Carrageenans have also been shown to selectively inhibit many enveloped virus [158], having antioxidant properties [159] and anti-tumor potential [160,161].…”

“…Kappa (κ)-carrageenan is extracted from Kappaphycus alvarezii (commercial identified as "cottonii"), while iota (ι)-carrageenan is generally extracted from Eucheuma denticulatum (commercial identified as "spinosum"). The other commercial carrageenan, the lambda (λ)-carrageenan is extracted from species belonging to the Gigartina and Chondrus genera (commercial identified as "Irish moss") [161]. Historically, countries of East and Southeast Asia are the biggest consumers of seaweeds, due to the culture of eating sushi.…”

Anti-neoplastic Potential of Flavonoids and Polysaccharide Phytochemicals in Glioblastoma

“…Carrageenans are a group of highly sulfated polysaccharide diversely found in marine red seaweeds; different subtypes of carrageenan are obtained from distinct species of Gigartinales (Rhodophyta) [218]. Structurally, carrageenans are composed of linear chains of d-galactopyranosyl units linked via alternated (1 → 3)-β-d-and (1 → 4)-α-d-glucoside, in which sugar units have one or two sulfate groups, with a molecular weight ranging from 30 and 5000 kDa; however, the average molecular weight of carrageenan is 200 and 800 kDa upon extraction [210].…”

“…However, commercially important carrageenans are categorized as kappa (k-), iota (i-), and lambda (λ-) carrageenan, which differ in the number and position of the sulfate groups. Kappa (κ)-carrageenan is mostly extracted from the tropical seaweed Kappaphycus alvarezii, while iota (ι)-carrageenan is mainly acquired from Eucheuma denticulatum and lambda (λ)-carrageenan is obtained from various species from the genera Gigartina and Chondrus [218].…”

Characterization of Bioactive Components in Edible Algae

“…In the study by Cotas et al (2019) [19], Gigartina pistillata (Rhodophyta) carrageenans, from specimens harvested from the western coast of Portugal, are evaluated against colorectal cancer stem cell (CSC)-enriched tumor-spheres. Carrageenans extracted from two G. pistillata life cycle phases have antitumor potential against colorectal cancer stem-like cells, especially the Lambda-family carrageenans extracted from the tetrasporophyte (T) phase [19].…”