Banca de QUALIFICAÇÃO: LAIS CRISTINA GUSMÃO FERREIRA PALHARES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : LAIS CRISTINA GUSMÃO FERREIRA PALHARES
DATE: 12/11/2019
TIME: 08:30
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TITLE:

Evaluation of the effect of a Chondroitin Sulfate obtained from the shrimp Litopenaeus vannamei on the melanoma development mediated by PAR-1 receptor.

KEY WORDS:

Chondroiti sulfate. Melanoma. PAR-1. Litopenaeus vannamei

PAGES: 9152
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUMMARY:

Thrombin, the main coagulation protease, is capable of activating countless cellular responses through activation of the protease activating receptor 1 (PAR-1), including several signalling pathways in cancer. In melanoma, activation of PAR-1 triggers cellular responses that favour the cancer development, such as platelet aggregation, proliferation, migration, oncogene expression and metastasis, as well as acting directly on angiogenesis, one of the primordial events in tumour biology. Thus, since thrombin intrinsically enables tumour progression through PAR-1, biomolecules capable of inhibiting this protease become interesting models in cancer research. The present work describes the structural characteristics and in vitro and in vivo antitumour potentials of a chondroitin sulfate isolated from the Litopenaeus vannamei shrimp cephalothorax (sCS). The compound was obtained after proteolysis, acetone treatment and purification by ion-exchange chromatography and desalted using gel filtration. Shrimp CS presented a 12KDa average molecular mass and analysis by enzymatic degradation and NMR revealed that the compound shows the unique GlcA 3-O-sulfate residue, as well as GalNAc 4-O-sulfate, GalNAc 6-O-sulfate and GalNAc 4,6-di-O-sulfate residues. Similar to heparin, L. vannamei CS was able to inhibit important activities for tumour progression. sCS reduced 66% of murine melanoma (B16F10) cell migration in the wound healing assay and 70% when analyzed by the transwell assay. Although the shrimp compound was unable to inhibit cell proliferation or to induce apoptosis and/or cell death after 24h incubation, it showed an important long-term antiproliferative effect, reducing the tumour cell clonogenicity by 75% at 100 µg/mL concentration (p <0.001), as well as inhibiting the anchorage-independent cell proliferation, an important indicator of tumour malignancy. These results may be inferred by the inhibitory effect presented by these GAGs on the in vitro gene expression of genes related to melanoma development, especially the Cx-43 gene. sCS compound also inhibited, in vitro, crucial molecules for tumour aggressiveness such as melanin and TNF-α by 52% and 75%, respectively. These results may explain the significant reduction in melanoma tumour growth (89% reduction) and the decrease of IL-1β, TNF-α and VEGF plasma levels (32%, 65% and 88% inhibition, respectively) in mice treated with 300 µg/kg/day of sCS. Additionally, sCS and heparin reduced in vivo mRNA levels of all evaluated genes, including PAR-1, as well as the immunohistochemical labelling for PAR-1 and VEGF in tumour and lung samples. The data shown here point to sCS as a potential biotechnological model for the development of new molecules which may be used in cancer therapy at the molecular level.

BANKING MEMBERS:
Presidente - 2832746 - MONIQUE GABRIELA DAS CHAGAS FAUSTINO ALVES
Interna - 1720860 - VANESSA DE PAULA SOARES RACHETTI
Externa à Instituição - JAILMA ALMEIDA DE LIMA - CRI