Antiproliferative and Antimicrobial Potentials of a Lectin from Aplysia kurodai (Sea Hare) Eggs.

Rubaiya Rafique Swarna,Syed Rashel Kabir,Yuki Fujii,Masao Yamada,Imtiaj Hasan,Sultana Rajia,Keisuke Hirashima,Sarkar M A Kawsar,Nawshin Arfin,Yukiko Ogawa,A K M Asaduzzaman,Yasuhiro Ozeki,Nanae Kobayashi

doi:10.3390/md19070394

Abstract

In recent years, there has been considerable interest in lectins from marine invertebrates. In this study, the biological activities of a lectin protein isolated from the eggs of Sea hare (Aplysia kurodai) were evaluated. The 40 kDa Aplysia kurodai egg lectin (or AKL-40) binds to D-galacturonic acid and D-galactose sugars similar to previously purified isotypes with various molecular weights (32/30 and 16 kDa). The N-terminal sequence of AKL-40 was similar to other sea hare egg lectins. The lectin was shown to be moderately toxic to brine shrimp nauplii, with an LC50 value of 63.63 µg/mL. It agglutinated Ehrlich ascites carcinoma cells and reduced their growth, up to 58.3% in vivo when injected into Swiss albino mice at a rate of 2 mg/kg/day. The morphology of these cells apparently changed due to AKL-40, while the expression of apoptosis-related genes (p53, Bax, and Bcl-XL) suggested a possible apoptotic pathway of cell death. AKL-40 also inhibited the growth of human erythroleukemia cells, probably via activating the MAPK/ERK pathway, but did not affect human B-lymphoma cells (Raji) or rat basophilic leukemia cells (RBL-1). In vitro, lectin suppressed the growth of Ehrlich ascites carcinoma and U937 cells by 37.9% and 31.8%, respectively. Along with strong antifungal activity against Talaromyces verruculosus, AKL showed antibacterial activity against Staphylococcus aureus, Shigella sonnei, and Bacillus cereus whereas the growth of Escherichia coli was not affected by the lectin. This study explores the antiproliferative and antimicrobial potentials of AKL as well as its involvement in embryo defense of sea hare.

Highlights

IntroductionMarine invertebrates possess diverse classes of lectins with various protein foldings and different carbohydrate-binding specificities [1,2,3,4,5]
Affinity chromatography showed different molecular masses of AKLs found in the eggs of Aplysia kurodai (Figure 1)
After applying the crude protein sample, the melibosylagarose affinity chromatography column was washed with TBS and bound lectins were eluted with 10 mM D-galacturonic acid or D-galactose-containing TBS

Summary

Introduction

Marine invertebrates possess diverse classes of lectins with various protein foldings and different carbohydrate-binding specificities [1,2,3,4,5]. Many of these lectins show affinity towards galactose-related carbohydrates and perform biological functions including antitumor and antimicrobial activities. Glycosylation pattern of cancer cells are altered, which affects multiple cellular mechanisms performed by lectins through their association with corresponding glycans [7]. As a result, this alteration supports their neoplastic progression [8,9]. Both these phenomena exhibit considerable influence of lectin–glycan interaction on the proliferation and regulation of tumor cells [5,10,11,12,14]

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Results

Discussion

Conclusion