Induction of mitochondria-dependent apoptosis by Abrus agglutinin derived peptides in human cervical cancer cell

The traditional uses, phytochemistry and pharmacology of Abrus precatorius L.: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Abrus precatorius L. (AP) is a folk medicine with a long-term medicinal history worldwide, which is extensively applied to various ailments, such as bronchitis, jaundice, hepatitis, contraception, tumor, abortion, malaria, etc. Meanwhile, its leaves are also served as tea in China, and its roots are employed as a substitute for Glycyrrhiza uralensis or as a raw material for the extraction of glycyrrhizin in India. Thus, AP is considered to be a plant with dual values of medicine and economy as well as its chemical composition and biological activity, which are of growing interest to the scientific community.

AIM OF REVIEW

In the review, the traditional application, botany, chemical constituents, pharmacological activities, and toxicity are comprehensively and systematically summarized.

MATERIALS AND METHODS

An extensive database retrieval was conducted to gather the specific information about AP from 1871 to 2022 using online bibliographic databases Web of Science, PubMed, SciFinder, Google Scholar, CNKI, and Baidu Scholar. The search terms comprise the keywords "Abrus precatorius", "phytochemistry", "pharmacological activity", "toxicity" and "traditional application" as a combination.

RESULTS

To date, AP is traditionally used to treat various diseases, including sore throat, cough, bronchitis, jaundice, hepatitis, abdominal pain, contraception, tumor, abortion, malaria, and so on. More than 166 chemical compounds have been identified from AP, which primarily cover flavonoids, phenolics, terpenoids, steroids, alkaloids, organic acids, esters, proteins, polysaccharides, and so on. A wide range of in vitro and in vivo pharmacological functions of AP have been reported, such as antitumor, antimicrobial, insecticidal, antiprotozoal, antiparasitic, anti-inflammatory, antioxidant, immunomodulatory, antifertility, antidiabetic, other pharmacological activities. The crushed seeds in powder or paste form were comparatively toxic to humans and animals by oral administration. Interestingly, the methanolic extracts were non-toxic to adult Wistar albino rats at various doses (200 and 400 mg/kg) daily.

CONCLUSIONS

The review focuses on the traditional application, botany, phytochemistry, pharmacological activities, and toxicity of AP, which offers a valuable context for researchers on the current research status and a reference for further research and applications of this medicinal plant.

Anticancer Activity of Periplanetasin-5, an Antimicrobial Peptide from the Cockroach Periplaneta americana

Cockroaches live in places where various pathogens exist and thus are more likely to use antimicrobial compounds to defend against pathogen intrusions. We previously performed an in silico analysis of the Periplaneta americana transcriptome and detected periplanetasin-5 using an in silico antimicrobial peptide prediction method. In this study, we investigated whether periplanetasin-5 has anticancer activity against the human leukemia cell line K562. Cell growth and survival of K562 cells treated with periplanetasin-5 were decreased in a dose-dependent manner. By using flow cytometric analysis, acridine orange/ethidium bromide (AO/EB) staining and DNA fragmentation, we found that periplanetasin-5 induced apoptotic and necrotic cell death in leukemia cells. In addition, these events were associated with increased levels of the pro-apoptotic proteins Fas and cytochrome c and reduced levels of the anti-apoptotic protein Bcl-2. Periplanetasin-5 induces the cleavage of pro-caspase-9, pro-caspase-8, pro-caspase-3, and poly (ADP-ribose) polymerase (PARP). The above data suggest that periplanetasin-5 induces apoptosis via both the intrinsic and extrinsic pathways. Moreover, caspase-related apoptosis was further confirmed by using the caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone (Z-VAD-FMK), which reversed the periplanetasin-5-induced reduction in cell viability. In conclusion, periplanetasin-5 caused apoptosis in leukemia cells, suggesting its potential utility as an anticancer therapeutic agent.

Structure-function and application of plant lectins in disease biology and immunity

Lectins are proteins with a high degree of stereospecificity to recognize various sugar structures and form reversible linkages upon interaction with glyco-conjugate complexes. These are abundantly found in plants, animals and many other species and are known to agglutinate various blood groups of erythrocytes. Further, due to the unique carbohydrate recognition property, lectins have been extensively used in many biological functions that make use of protein-carbohydrate recognition like detection, isolation and characterization of glycoconjugates, histochemistry of cells and tissues, tumor cell recognition and many more. In this review, we have summarized the immunomodulatory effects of plant lectins and their effects against diseases, including antimicrobial action. We found that many plant lectins mediate its microbicidal activity by triggering host immune responses that result in the release of several cytokines followed by activation of effector mechanism. Moreover, certain lectins also enhance the phagocytic activity of macrophages during microbial infections. Lectins along with heat killed microbes can act as vaccine to provide long term protection from deadly microbes. Hence, lectin based therapy can be used as a better substitute to fight microbial diseases efficiently in future.

Polynuclear zinc(II) complexes of thiosemicarbazone: Synthesis, X-ray structure and biological evaluation

Two new dimeric Zn(II) ([{ZnL¹(DMSO₂)}₂]·DMSO (1), [{ZnL²Cl}₂] (2)) and a novel tetrameric Zn(II) complex ([(Zn₂L³)₂(μ-OAc)₂(μ₃-O)₂] (3)), where H₂L¹ = 4-(p-methoxyphenyl) thiosemicarbazone of o-hydroxynapthaldehyde, HL² = 4-(p-methoxyphenyl)thiosemicarbazone of benzoyl pyridine and H₂L³ = 4-(p-chlorophenyl)thiosemicarbazone of o-vanillin are reported. Ligands and their complexes were characterized by spectroscopic and single crystal X-ray diffraction techniques. In addition, the complexes exhibited good binding affinity towards HSA (10¹² M^-1), which is supported by their ability to quench the tryptophan fluorescence emission spectra of HSA. The complexes were also screened for their DNA binding propensity through UV-vis absorption titration, circular dichroism and fluorescence spectral studies. Results show that they effectively interact with CT-DNA through an intercalative mode of binding, with binding constants ranging from 10³ to 10⁴ M^-1. Among the three complexes 1 has the highest binding affinity towards CT-DNA. Further, the phosphatase activity was evaluated using bis(2,4-dinitrophenyl)phosphate (BDNPP) as substrate, however, the complexes did not yield any measurable catalytic activity. Nevertheless the complexes showed significant cytotoxic potential against HeLa and HT-29 cancer cell lines that was assessed through MTT assay and DAPI staining. Remarkably, complex 1 showed better activity than cisplatin against HT-29 cell line.

Plant lectins in cancer therapeutics: Targeting apoptosis and autophagy-dependent cell death

Plant lectins are non-immunoglobin in nature and bind to the carbohydrate moiety of the glycoconjugates without altering any of the recognized glycosyl ligands. Plant lectins have found applications as cancer biomarkers for recognizing the malignant tumor cells for the diagnosis and prognosis of cancer. Interestingly, plant lectins contribute to inducing cell death through autophagy and apoptosis, indicating their potential implication in cancer inhibitory mechanism. In the present review, anticancer activities of major plant lectins have been documented, with a detailed focus on the signaling circuit for the possible molecular targeted cancer therapy. In this context, several lectins have exhibited preclinical and clinical significance, driving toward therapeutic potential in cancer treatment. Moreover, several plant lectins induce immunomodulatory activities, and therefore, novel strategies have been established from preclinical and clinical investigations for the development of combinatorial treatment consisting of immunotherapy along with other anticancer therapies. Although the application of plant lectins in cancer is still in very preliminary stage, advanced high-throughput technology could pave the way for the development of lectin-based complimentary medicine for cancer treatment.

p73 induction by Abrus agglutinin facilitates Snail ubiquitination to inhibit epithelial to mesenchymal transition in oral cancer

BACKGROUND

Epithelial-to-mesenchymal transition (EMT), a key step in oral cancer progression, is associated with invasion, metastasis, and therapy resistance, thus targeting the EMT represents a critical therapeutic strategy for the treatment of oral cancer metastasis. Our previous study showed that Abrus agglutinin (AGG), a plant lectin, induces both intrinsic and extrinsic apoptosis to activate the tumor inhibitory mechanism.

OBJECTIVE

This study aimed to investigate the role of AGG in modulating invasiveness and stemness through EMT inhibition for the development of antineoplastic agents against oral cancer.

METHODS

The EMT- and stemness-related proteins were studied in oral cancer cells using Western blot analysis and fluorescence microscopy. The potential mechanisms of Snail downregulation through p73 activation in FaDu cells were evaluated using Western blot analysis, immunoprecipitation, confocal microscopy, and molecular docking analysis. Immunohistochemical staining of the tumor samples of AGG-treated FaDu-xenografted nude mice was performed.

RESULTS

At the molecular level, AGG-induced p73 suppressed Snail expression, leading to EMT inhibition in FaDu cells. Notably, AGG promoted the translocation of Snail from the nucleus to the cytoplasm in FaDu cells and triggered its degradation through ubiquitination. In this setting, AGG inhibited the interaction between Snail and p73 in FaDu cells, resulting in p73 activation and EMT inhibition. Moreover, in epidermal growth factor (EGF)-stimulated FaDu cells, AGG abolished the upregulation of extracellular signal-regulated kinase (ERK)1/2 that plays a pivotal role in the upregulation of Snail to regulate the EMT phenotypes. In immunohistochemistry analysis, FaDu xenografts from AGG-treated mice showed decreased expression of Snail, SOX2, and vimentin and increased expression of p73 and E-cadherin compared with the control group, confirming EMT inhibition as part of its anticancer efficacy against oral cancer.

CONCLUSION

In summary, AGG stimulates p73 in restricting EGF-induced EMT, invasiveness, and stemness by inhibiting the ERK/Snail pathway to facilitate the development of alternative therapeutics for oral cancer.

Abrus agglutinin is a potent anti-proliferative and anti-angiogenic agent in human breast cancer

Abrus agglutinin (AGG), a plant lectin isolated from the seeds of Abrus precatorius, has documented antitumor and immunostimulatory effects in murine models. To examine possible antitumor activity against breast cancer, we established human breast tumor xenografts in athymic nude mice and intraperitoneally administered AGG. AGG inhibited tumor growth and angiogenesis as confirmed by monitoring the expression of Ki-67 and CD-31, respectively. In addition, TUNEL positive cells increased in breast tumors treated with AGG suggesting that AGG mediates anti-tumorigenic activity through induction of apoptosis and inhibition of angiogenesis. On a molecular level, AGG caused extrinsic apoptosis through ROS generation that was AKT-dependent in breast cancer cells, without affecting primary mammary epithelial cells, suggesting potential cancer specificity of this natural compound. In addition, using HUVECs, AGG inhibited expression of the pro-angiogenic factor IGFBP-2 in an AKT-dependent manner, reducing angiogenic phenotypes both in vitro and in vivo. Overall, the present results establish that AGG promotes both apoptosis and anti-angiogenic activities in human breast tumor cells, which might be exploited for treatment of breast and other cancers.

Oxidovanadium(v) complexes of aroylhydrazones incorporating heterocycles: synthesis, characterization and study of DNA binding, photo-induced DNA cleavage and cytotoxic activities

The interaction of four neutral oxidovanadium(v) complexes with DNA and their cytotoxic activities have been reported.

Evaluation of the cell cytotoxicity and DNA/BSA binding and cleavage activity of some dioxidovanadium(V) complexes containing aroylhydrazones

Three dioxidovanadium(V) complexes [VO2L(1-3)] (1-3) [HL(1)=1-napthoyl hydrazone of 2-acetyl pyridine, HL(2)=2-furoyl hydrazone of 2-acetyl pyridine and H2L(3)=isonicotinoyl hydrazone of 2-hydroxy benzaldehyde] have been reported. All the complexes were characterized by various spectroscopy (IR, UV-visible and NMR) and the molecular structures of 1 and 2 were characterized by single crystal X-ray diffraction technique. Structural report established five-coordinate geometries, distorted toward square pyramidal for each of 1 and 2, based on a tridentate -O,N,N coordinating anion and two oxido-O atoms. The experimental results show that the complexes interact with calf-thymus DNA (CT-DNA) possibly by a groove binding mode, with binding constants of ~10(5)M(-1). All complexes show good photo-induced cleavage of pUC19 supercoiled plasmid DNA with complex 1 showing the highest photo-induced DNA cleavage activity of ~68%. 1-3 also exhibit moderate binding affinity in the range of 10(3)-10(4)M(-1) towards bovine serum albumin (BSA), while all the complexes show good photo-induced BSA cleavage activity. Moreover the antiproliferative activity of all these complexes was studied, which reveal all compounds are significantly cytotoxic towards the HeLa cell line.

Ethno botanical and Phytophrmacological potential of Abrus precatorius L.: A review

Medicinal plants are being widely used, either as a single drug or in combination in health care delivery system. Medicinal plants can be important source of previously unknown chemical substances with potential therapeutic effects. Abrus precatorius L. is commonly known as Gunja or Jequirity and abundantly found all throughout the plains of India, from Himalaya down to Southern India and Ceylon. This plant is having medicinal potential to cure various diseases. The roots, leaves and seeds of this plant are used for different medicinal purpose. It principally contains flavonoids, triterpene glycosides, abrin and alkaloids. The plant have been reported for neuromuscular effects, neuro-protective, abortifacient, antiepileptic, anti-viral, anti-malarial, antifertility, nephroprotective, immunomodulator, immunostimulatory properties, anti-inflammatory activity, antidiabetic effect, etc. As this is a potential medicinal plant, present review reveals chemical constituents of leaf, root and seeds of Abrus precatorius. The plant is considered as a valuable source of unique natural products for development of medicines against various diseases and also for the development of industrial products.

Antitumor effect of soybean lectin mediated through reactive oxygen species-dependent pathway

AIMS

The present study evaluated the potential role of soybean lectin's (SBL) anticancer effect in vitro in different cancer cell lines and the therapeutic effectiveness in vivo in Dalton's lymphoma (DL) bearing mice model.

MAIN METHODS

The effect of SBL on cell growth and viability was measured using MTT assay in different cancer cells in vitro. Apoptosis, autophagic cell death, DNA-damaging potential and reactive oxygen species (ROS) were analyzed in HeLa cells. The in vivo efficacy of SBL was demonstrated in Dalton's lymphoma (DL) bearing mice.

KEY FINDINGS

SBL demonstrated clear, strong antiproliferative activity without affecting normal cells; however, heat denaturation of SBL diminished the antiproliferative efficacy of molecule as demonstrated by MTT assay. A sharp 74.51 ± 3.5% and 82.95 ± 5.8% inhibition of tumor cell proliferation in DL mice occurred when SBL was administered at a dosage of 1 and 2mg/kg body weight (i.p.), respectively, for ten days with the induction of autophagic and apoptotic cell death. An in vitro investigation revealed that SBL-mediated autophagy, apoptosis and DNA damage in HeLa cells were inflicted through the generation of ROS in a dose-dependent manner. Interestingly, pre-treating HeLa cells with N-acetylcysteine (NAC), a typical ROS scavenger, led to a noticeable reduction in SBL-induced autophagy, apoptosis and DNA-damaging activities, suggesting that SBL's antitumor potential was governed by ROS activation.

SIGNIFICANCE

In this study, we evaluated the apoptotic, autophagic death, and DNA-damaging effects of SBL in cancer cells, which may have the potential to be used as a phyto-derived protein for cancer therapy.

Biochemical analysis and antitumour effect of Abrus precatorius agglutinin derived peptides in Ehrlich's ascites and B16 melanoma mice tumour model

Anticancer and immunostimulatory properties of tryptic digest peptides of Abrus precatorius agglutinin protein (10kDAGP) have already been reported. Here attempt has been made to further validate anticancer properties of 10kDAGP peptides in Ehrlich's ascites carcinoma (EAC) and B16 melanoma (B16M) bearing mice models and to analyze 10kDAGP by anion exchange chromatography and RP-HPLC for obtaining the bioactive fraction from the total peptide pool. 10kDAGP treatment decreased the tumour pack volume by ∼82% for EAC and 58.8% for B16M. It also showed increase in ex vivo proliferation of splenocyte and thymocyte isolated from tumour bearing mice and increase in TNF-α and Interferon-γ in splenocyte culture supernatant. From chromatographic analysis it was found that anionic peptide fraction may be responsible for anti-proliferative activities of 10kDAGP. As most anticancer peptides are cationic in nature, further studies regarding bioactivity of anionic peptide fraction may lead to novel anticancer peptides and pathways of action.

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

AIM

Abrus agglutinin (AGG) from the seeds of Indian medicinal plant Abrus precatorius belongs to the class II ribosome inactivating protein family. In this study we investigated the anticancer effects of AGG against human hepatocellular carcinoma in vitro and in vivo.

METHODS

Cell proliferation, DNA fragmentation, Annexin V binding, immunocytofluorescence, Western blotting, caspase activity assays and luciferase assays were performed to evaluate AGG in human liver cancer cells HepG2. Immunohistochemical staining and TUNEL expression were studied in tumor samples of HepG2-xenografted nude mice.

RESULTS

AGG induced apoptosis in HepG2 cells in a dose- and time-dependent manner. AGG-treated HepG2 cells demonstrated an increase in caspase 3/7, 8 and 9 activities and a sharp decrease in the Bcl-2/Bax ratio, indicating activation of a caspase cascade. Co-treatment of HepG2 cells with AGG and a caspase inhibitor or treatment of AGG in Bax knockout HepG2 cells decreased the caspase 3/7 activity in comparison to HepG2 cells exposed only to AGG. Moreover, AGG decreased the expression of Hsp90 and suppressed Akt phosphorylation and NF-κB expression in HepG2 cells. Finally, AGG treatment significantly reduced tumor growth in nude mice bearing HepG2 xenografts, increased TUNEL expression and decreased CD-31 and Ki-67 expression compared to levels observed in the untreated control mice bearing HepG2 cells.

CONCLUSION

AGG inhibits the growth and progression of HepG2 cells by inducing caspase-mediated cell death. The agglutinin could be an alternative natural remedy for the treatment of human hepatocellular carcinomas.

Rhizoctonia bataticola lectin (RBL) induces caspase-8-mediated apoptosis in human T-cell leukemia cell lines but not in normal CD3 and CD34 positive cells

We have previously demonstrated immunostimulatory activity of a fungal lectin, Rhizoctonia bataticola lectin (RBL), towards normal human peripheral blood mononuclear cells. The present study aimed to explore the anticancer activities of RBL using human leukemic T-cell lines, Molt-4, Jurkat and HuT-78. RBL exhibited significant binding (>90%) to the cell membrane that was effectively inhibited by complex glycoproteins such as mucin (97% inhibition) and asialofetuin (94% inhibition) but not simple sugars such as N-acetyl-D-galactosamine, glucose and sucrose. RBL induced a dose and time dependent inhibition of proliferation and induced cytotoxicity in the cell lines. The percentage of apoptotic cells, as determined by hypodiploidy, was 33% and 42% in Molt-4 and Jurkat cells, respectively, compared to 3.11% and 2.92% in controls. This effect was associated with a concomitant decrease in the G0/G1 population. Though initiator caspase-8 and -9 were activated upon exposure to RBL, inhibition of caspase-8 but not caspase-9 rescued cells from RBL-induced apoptosis. Mechanistic studies revealed that RBL induced cleavage of Bid, loss of mitochondrial membrane potential and activation of caspase-3. The expression of the anti-apoptotic proteins Bcl-2 and Bcl-X was down regulated without altering the expression of pro-apoptotic proteins- Bad and Bax. In contrast to leukemic cells, RBL did not induce apoptosis in normal PBMC, isolated CD3+ve cells and undifferentiated CD34+ve hematopoietic stem and progenitor cells (HSPCs). The findings highlight the differential effects of RBL on transformed and normal hematopoietic cells and suggest that RBL may be explored for therapeutic applications in leukemia.

Detecting the somatic mutations spectrum of Chinese lung cancer by analyzing the whole mitochondrial DNA genomes

To detect the somatic mutations and character its spectrum in Chinese lung cancer patients. In this study, we sequenced the whole mitochondrial DNA (mtDNA) genomes for 10 lung cancer patients including the primary cancerous, matched paracancerous normal and distant normal tissues. By analyzing the 30 whole mtDNA genomes, eight somatic mutations were identified from five patients investigated, which were confirmed with the cloning and sequencing of the somatic mutations. Five of the somatic mutations were detected among control region and the rests were found at the coding region. Heterogeneity was the main character of the somatic mutations in Chinese lung cancer patients. Further potential disease-related screening showed that, except the C deletion at position 309 showed AD-weakly associated, most of them were not disease-related. Although the role of aforementioned somatic mutations was unknown, however, considering the relative higher frequency of somatic mutations among the whole mtDNA genomes, it hints that detecting the somatic mutation(s) from the whole mtDNA genomes can serve as a useful tool for the Chinese lung cancer diagnostic to some extent.

Plants and cervical cancer: an overview

INTRODUCTION

Cervical cancer, the second most common gynecological malignant tumor seriously harmful to the health of women, remains a leading cause of cancer-related death for women in developing countries. Although a large amount of scientific research has been reported on plants as a natural source of treatment agents for cervical cancer, it is currently scattered across various publications. A systematic summary and knowledge of future prospects are necessary to facilitate further plant studies for anti-cervical cancer agents.

AREAS COVERED

This review generalizes and analyzes the current knowledge on the anti-cervical cancer properties and mechanisms involved for plants, and discusses the future prospects for the application of these plants.

EXPERT OPINION

This review mainly focuses on the plants which have been scientifically tested in vitro and/or in vivo and proved as potential agents for the treatment of cervical cancer. The failure of conventional chemotherapy to reduce mortality as well as serious side effects involved makes natural products ideal candidates for exerting synergism and attenuation effects on anticancer drugs. Although the chemical components and mechanisms of action of natural plants with anti-cervical cancer potential have been investigated, many others remain unknown. More investigations and clinical trials are necessary to make use of these medical plants reasonably.

A novel polypeptide from Meretrix meretrix Linnaeus inhibits the growth of human lung adenocarcinoma

A novel polypeptide (Mere15) was purified from Meretrix meretrix Linnaeus by ammonium sulfate fractionation, ion exchange, gel filtration and reversed phase chromatography. Mere15 exhibited selective cytotoxicity to several human cancer cells. In vivo study showed that Mere15 significantly suppressed the growth of human lung adenocarcinoma A549 xenograft in nude mice. The mechanism was associated with a G2/M phase arrest followed by apoptosis, including membrane blebbing, loss of mitochondrial membrane potential, externalization of phosphatidylserine, chromosome condensation and DNA fragmentation. Western blot analysis showed that the intrinsic pathway was involved in Mere15-induced apoptosis. These results suggest that Mere15 may have therapeutic potential for the treatment of non-small-cell lung carcinoma.

Lectins: production and practical applications

Lectins are proteins found in a diversity of organisms. They possess the ability to agglutinate erythrocytes with known carbohydrate specificity since they have at least one non-catalytic domain that binds reversibly to specific monosaccharides or oligosaccharides. This articles aims to review the production and practical applications of lectins. Lectins are isolated from their natural sources by chromatographic procedures or produced by recombinant DNA technology. The yields of animal lectins are usually low compared with the yields of plant lectins such as legume lectins. Lectins manifest a diversity of activities including antitumor, immunomodulatory, antifungal, HIV-1 reverse transcriptase inhibitory, and anti-insect activities, which may find practical applications. A small number of lectins demonstrate antibacterial and anti-nematode activities.

In vitro immunostimulatory properties of Abrus lectins derived peptides in tumor bearing mice

In vitro immunostimulatory effect of Abrus lectins derived peptide fractions (AGP and ABP) was investigated in DL bearing mice. Both AGP and ABP were found to activate splenocytes and induced production of cytokines like IL-2, IFN-gamma and TNF-alpha indicating a Th1 type of immune response. Analysis of in vitro treated splenocytes by flow cytometry revealed an increase in percentage of T and B cell with high expression of activation markers (CD25(+) and CD71(+)). At the same time, expression of co-stimulatory markers was significantly high compared to tumor control. The tumor associated macrophages were able to stimulate NO production, IL-1 secretion, increased phagocytosis and decreased expression of mannose receptor. It was also observed that NK cell was activated by AGP and ABP. These results suggest that both AGP and ABP act as immunostimulants in vitro in DL bearing mice.

Inhibitory effect of Abrus abrin-derived peptide fraction against Dalton's lymphoma ascites model

Peptides derived from larger molecules that are important modulators in cancer regression are becoming leads for development of therapeutic drugs. It has been reported that Abrus abrin, isolated from the seeds of Abrus precatorius, showed in vitro and in vivo antitumor properties by the induction of apoptosis. The present study was designed to evaluate the in vivo therapeutic effectiveness of abrin-derived peptide (ABP) fraction in Dalton's lymphoma (DL) mice model. The lethal dose (LD(50)) of ABP was found to be 2.25 mg/kg body weight and further the acute toxicity was determined with sublethal doses in normal mice. The acute toxicity like body weight, peripheral blood cell count, lympho-hematological and biochemical parameters remained unaffected till 200 microg/kg body weight of ABP. The sublethal doses of ABP showed very significant growth inhibitory properties in vivo DL mice model. There were 24%, 70.8% and 89.7% reductions in DL cell survival in 25, 50 and 100 microg/kg body weight of ABP, respectively. Analysis of the growth inhibitory mechanism in DL cells revealed nuclear fragmentation, and condensation with the appearance of the sub-G(0)/G(1) peak is indicative of apoptosis. Further, the Western blotting showed that apoptosis was mediated by the reduction in the ratio of Bcl-2 and Bax protein expression, and activation of caspase-3 through the release of cytochrome c in DL cells. Kaplan-Meier survival analysis showed an effective antitumor response (104.6 increase in life span (ILS) %) with a dose of 100 microg/kg body weight.

Targeting tumors with peptides from natural sources

Peptide-based therapies offer the potential for non-genotoxic, genotype-specific alternatives, or adjuvants, to the current range of traditional cancer treatments. Such a patient-tailored cancer-cell-directed therapeutic approach should have fewer side effects and could well be more effective than the current drug- or combination-based regimens. Here, we review the potential of novel natural anticancer peptides such as necrotic peptides, apoptotic peptides, function-blocking peptides, antiangiogenic peptides and immunostimulatory peptides in the context of their ability to induce tumor regression. We focus on the therapeutic prospects of anticancer peptides and their possible application in tumor therapy.