Anti-tumor activity and immunological modification of ribosome-inactivating protein (RIP) from <italic>Momordica charantia</italic> by covalent attachment of polyethylene glycol

Abstract

Ribosome-inactivating proteins (RIPs) are a family of enzymes that depurinate rRNA and inhibit protein biosynthesis. Here we report the purification, apoptosis-inducing activity, and polyethylene glycol (PEG) modification of RIP from the bitter melon seeds. The protein has a homogenous N-terminal sequence of NAsp- Val-Ser-Phe-Arg. Moreover, the RIP displayed strong apoptosis-inducing activity and suppressed cancer cell growth. This might be attributed to the activation of caspases-3. To make it available for in vivo application, the immunogenicity of RIP was reduced by chemical modification with 20 kDa (mPEG)(2)-Lys-NHS. The inhibition activity of both PEGylated and non-PEGylated RIP against cancer cells was much stronger than against normal cells, and the antigenicity of PEGylated RIP was reduced significantly. Our results suggested that the PEGylated RIP might be potentially developed as anti-cancer drug.

A PVP-extract fungal protein of Omphalia lapideacens and its antitumor activity on human gastric tumors and normal cells

“…At present, many proteins from different sources have been found to possess antitumor activity (28)(29)(30)(31)(32). Of these, fungal proteins are the major one, in which fungal immunomodulatory protein (FIP), ribosome-inactivating protein (RIP), lectins, and glycoproteins, are involved, due to their favorable effect against a variety of tumors (33).…”

Inhibitory effect of alpha-momorcharin and its PEGylated conjugates on the migration and invasion of human choriocarcinoma JAR cells via reduced matrix metalloproteinase-2 (MMP-2) activity

“…However, caspase proteins are recruited during classical apoptosis via the activation of the apoptotic signaling pathway (Vaux et al, 1999). Our previous study indicated that α-MMC and its PEGylated conjugates decreased the proliferation of human epidermal carcinoma A431 cells via caspase 3-dependent apoptosis (Li et al, 2009). The established choriocarcinoma JAR cell line has important advantages for in vitro study, such as homogeneity, a low spontaneous rate of apoptosis, and the practicality of its progression procedures (Gaus et al, 1997).…”

“…Natural and modified α-MMC were prepared as described previously (Li et al, 2009). The purification of α-MMC was accomplished in the following four steps: The supernatant was extracted from bitter melon seeds with acetate buffer (50 mM, pH 5.0), followed by ammonium sulfate fractionation precipitation (35 to 70%), MacroCap SP chromatography with a 0 -0.2 M NaCl linear gradient in 20 mM phosphate buffer (PB, pH 7.0) and Superdex 75 chromatography with 20 mM PB containing 0.15 M NaCl, pH 7.0.…”

“…Six hours after initial cell attachment, we added 20 μL of medium or an appropriately native or PEG-α-MMC diluted by stock solutions to produce a final concentrations of 0.012, 0.06, 0.3 and 1.5 mg/ml, which were incubated 24, 48 and 72 h (four replicates per concentration). The procedure was based on a previously described method (Li et al, 2009). Cell proliferation was determined as the formazan absorbance 570 nm, which was expressed as the ratio of treated to control values.…”

Kuguacin J, a Triterpenoid from Momordica charantia Linn: A Comprehensive Review of Anticarcinogenic Properties

“…Administration of MCP30 decreased PC3 human prostate cancer cell growth by the induction of apoptosis in nude mice [71]. Recent studies further indicate that the chemical modification and reduction of ribosome-inactivating protein in BME, significantly reduced its in vivo immunogenicity, but retained its antiproliferative activity as measured by DNA fragmentation and caspase-3 activation [100]. Cucurbitane-type triterpenoids, charantosides, from a methanol extract of the fruits of MC also inhibited mouse skin carcinogenesis induced by 7,12-dimethylbenz[a]anthracene (DMBA) or peroxynitrite plus 12-O-tetradecanoylphorbol-13-acetate (TPA) [45] α-ESA in bitter melon seed oil suppressing the growth of DLD-1 human colon cancer cells by apoptosis induction via lipid peroxidation [101].…”