A new Phaseolus vulgaris lectin induces selective toxicity on human liver carcinoma Hep G2 cells

Abstract

We describe here the purification and characterization of a new Phaseolus vulgaris lectin that exhibits selective toxicity to human hepatoma Hep G2 cells and lacks significant toxicity on normal liver WRL 68 cells. This polygalacturonic acid-specific lectin (termed BTKL) was purified from seeds of P. vulgaris cv. Blue tiger king by liquid chromatography techniques. The 60-kDa dimeric lectin showed strong and broad-spectrum hemagglutinating activity toward human, rabbit, rat, and mouse erythrocytes. Bioinformatic analysis unveils substantial N-terminal sequence similarity of BTKL to other Phaseolus lectins. Among a number of tumor cells tested, BTKL exhibits potent anti-Hep G2 activity which is associated with (1) induction of DNA fragmentation, (2) production of apoptotic bodies and chromatin condensation, (3) triggering of cell apoptosis and necrosis, and (4) depolarization of mitochondrial membrane (low ΔΨm). Furthermore, BTKL could induce inducible nitric oxide synthase (iNOS) expression and subsequent nitric oxide production in vitro in mouse macrophages, which may contribute to its antitumor activity. In addition, BTKL could bring about a significant dose-dependent increase in the production of mRNAs of proinflammatory cytokines including interleukin-1 beta, interleukin-2, tumor necrosis factor alpha, and interferon-gamma. In sum, the antitumor activity and mechanism of BTKL provided here suggest that it has potential therapeutic value for human liver cancer.

Momordica Charantia Lectin, a Type II Ribosome Inactivating Protein, Exhibits Antitumor Activity toward Human Nasopharyngeal Carcinoma Cells In Vitro and In Vivo

“…Effects of MCL on apoptosis of tumor cell were examined with a FACSort flow cytometer (Becton Dickinson) using Annexin V-FITC/propidum iodide (PI; BD Phamingen) double staining as previously described (15). Furthermore, observations of apoptotic bodies and chromatin condensation were made with Hoechst 33342 staining (1 mmol/L) and visualized under UV illumination with a NIKON TE2000 microscope (Nikon; ref.…”

“…Furthermore, observations of apoptotic bodies and chromatin condensation were made with Hoechst 33342 staining (1 mmol/L) and visualized under UV illumination with a NIKON TE2000 microscope (Nikon; ref. 15). Moreover, apoptotic bodies were counted in 3 different fields of microscopic observation.…”

“…16). On the other hand, measurement of changes of mitochondrial transmembrane potential (DÉm) was made using the same procedure, but with JC-1 staining at a concentration of 2.5 mg/mL (15). The mechanism is that JC-1 exists in monomeric form in the cytosol (emitting green fluorescence) and also accumulates as aggregates in the mitochondria …”

“…L-NAME or SB-203580 was added 1 hour prior to MCL. Second, the generation of nitrite and nitrate, as the surrogate markers for NO, in the cell culture supernatant was determined by using Griess reagent, as previously described (14,15).…”

Abrus agglutinin suppresses human hepatocellular carcinoma in vitro and in vivo by inducing caspase-mediated cell death

“…In this regard, several plant lectins, including Phaseolus vulgaris lectin, Concanavalin-A (ConA) and lectins from Astragalus membranaceus and Momordica charantia, induce apoptotic cell death in cancer cells that originate from different sources and tissues [26][27][28][29][30] . Additionally, ConA has been reported to elicit autophagic cell death in HCC [31] .…”