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- Elucidating the mechanisms Involved in the cytotoxicity induced by marine cyanobacteria strains against the RKO colon carcinoma cell linePublication . Freitas, S.; Urbatzka, R.; Osório, H.; Costa, M.; Barros, Piedade; Vasconcelos, V.; Martins, RosárioCyanobacteria are known to synthesize secondary metabolites that may have potential as drugs for the treatment of human diseases such as cancer. Previous studies on marine cyanobacteria isolated from the Portuguese coast revealed strains of the picoplanktonic genera Cyanobium and Synechocystis as potential sources of anticancer compounds. The ethyl acetate fraction of the strains Cyanobium sp. LEGE06113 and the Synechocystis salina LEGE06155 was found to reduce cell viability of cancer cell lines. This work aimed to elucidate the mechanisms involved in the cytotoxicity of this strains in the colon adenocarcinoma cell line RKO by employing real-time PCR (RT-PCR) for genes involved in cell cycle and apoptosis, by flow cytometry for cell cycle and by two-dimensional gel electrophoresis for protein expression. RT-PCR results revealed differences in mRNA expression of genes CCNB1 (cell cycle) and BCL-2 (apoptosis). Flow cytometry results revealed a decrease in the G0/G1 and S phase and increased its number in the G2/M phase, which is in accordance with the lower expression of CCNB1. The proteomic results demonstrated different protein patterns comparing treatment groups with control. Proteins differentially regulated in exposed RKO cells were involved in cell cycle regulation, apoptosis, cell structure, protein regulation and cell metabolism. Although several of these proteins were identified in cells exposed to both cyanobacterial extracts, the data provides an indication that the cytotoxicity is induced by different toxic mechanisms in LEGE06113 and LEGE06155 fractions.
- Anticancer potential of spores of the soil fungus Pisolithus tinctoriusPublication . Oliveira, Rui S.; Alves, Ricardo; Preto, Marco; Martins, RosárioCancer is one of the major causes of death worldwide being the search for new anticancer drugs essential for the treatment of this disease. The sporocarps of the soil fungus Pisolithus tinctorius contain pisosterol, a triterpene that has been shown to have antitumor activity against some cancer cell lines. Nevertheless, no studies have focused on the anticancer potential of other structures such as spores, and so the anticancer potential of P. tinctorius, remains largely unknown. The main objective of this study was to evaluate the potential of P. tinctorius spores as a source of anticancer compounds.
- Insights into the potential of picoplanktonic marine cyanobacteria strains for cancer therapies – Cytotoxic mechanisms against the RKO colon cancer cell linePublication . Freitas, Sara; Martins, Rosario; Campos, Alexandre; Azevedo, Joana; Osório, Hugo; Costa, Margarida; Barros, Piedade; Vasconcelos, Vitor; Urbatzka, RalphIn this work, we analysed the potential of picoplanktonic marine cyanobacteria strains as a source of anticancer compounds by elucidating the cytotoxic mechanisms of an ethyl acetate fraction of Cyanobium sp. (LEGE06113) and the Synechocystis salina (LEGE06155) on the RKO colon adenocarcinoma cell line.
- Exploring bioactive properties of marine cyanobacteria Isolated from the Portuguese coast: high potential as a source of anticancer compoundsPublication . Costa, Margarida; Garcia, Mónica; Costa-Rodrigues, Joao; Costa, Maria Sofia; Ribeiro, Maria João; Fernandes, Maria Helena; Barros, Piedade; Barreiro, Aldo; Vasconcelos, Vítor; Martins, RosarioThe oceans remain a major source of natural compounds with potential in pharmacology. In particular, during the last few decades, marine cyanobacteria have been in focus as producers of interesting bioactive compounds, especially for the treatment of cancer. In this study, the anticancer potential of extracts from twenty eight marine cyanobacteria strains, belonging to the underexplored picoplanktonic genera, Cyanobium, Synechocystis and Synechococcus, and the filamentous genera, Nodosilinea, Leptolyngbya, Pseudanabaena and Romeria, were assessed in eight human tumor cell lines. First, a crude extract was obtained by dichloromethane:methanol extraction, and from it, three fractions were separated in a Si column chromatography. The crude extract and fractions were tested in eight human cancer cell lines for cell viability/toxicity, accessed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactic dehydrogenase release (LDH) assays. Eight point nine percent of the strains revealed strong cytotoxicity; 17.8% showed moderate cytotoxicity, and 14.3% assays showed low toxicity. The results obtained revealed that the studied genera of marine cyanobacteria are a promising source of novel compounds with potential anticancer activity and highlight the interest in also exploring the smaller filamentous and picoplanktonic genera of cyanobacteria.
- Evaluation of the anticancer potential of the macrofungus Pisolithus arhizus mycelium and culture mediumPublication . Santos, Germana; Preto, Marco; Vasconcelos, Vítor; Martins, Rosário; Oliveira, Rui S.; Martins, RosarioMacrofungi produce remarkable biomedical products that can make a significant contribution to health. Pisolithus arhizus is a fungal species of the phylum Basidiomycota. It is mainly found in association with the roots of some trees species, establishing a mutualistic relationship with them, facilitating the absorption of nutrients from the soil in exchange for carbohydrates produced by the host plant. As recently reviewed by us, this macrofungus has aroused great interest due to its promising therapeutic properties and bioactive effects. Crude extracts were prepared from the mycelium and culture medium of P.arhizus using a mixture of dichloromethane:methanol (2:1. The extracts were then separated into nine fractions using vacuum liquid chromatography. The fractions were tested for cytotoxicity against the RKO colon adenocarcinoma cell line and 3T3 fibroblasts cell line. Cell viability was assessed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) reduction assay. Preliminary results revealed a dose dependent cytotoxicity against RKO cell line with no significant cytotoxicity to 3T3 cell lines, in fractions B and C. Those fractions corresponded to extraction with 70% Hex:30% EtOAc and 60% Hex:40% EtOAc, respectively. The results indicate that P.arhizus mycelium is a source of compounds with anticancer activity. However, more in-depth studies are needed to analyze the chemical compounds from the various parts of P. arhizus and investigate their biological and toxicological activities. Exploring the bioactive potential of P. arhizus is key to developing a complete understanding of its therapeutic benefits.