Exploring the Underlying Mechanisms of Preventive Treatment Related to Dietary Factors for Gastric Diseases

Gastric diseases have emerged as one of the main chronic diseases in humans, leading to considerable health, social, and economic burdens. As a result, using food or "food and medicinal homologous substances" has become an effective strategy to prevent gastric diseases. Diet may play a crucial role in the prevention and mitigation of gastric diseases, particularly long-term and regular intake of specific dietary components that have a protective effect on the stomach. These key components, extracted from food, include polysaccharides, alkaloids, terpenoids, polyphenols, peptides, probiotics, etc. The related mechanisms involve regulating gastric acid secretion, protecting gastric mucosa, increasing the release of gastric defense factors, decreasing the level of inflammatory factors, inhibiting Helicobacter pylori infection, producing antioxidant effects or reducing oxidative damage, preventing gastric oxidative stress by inhibiting lipid peroxides, activating Nrf2 signaling pathway, and inhibiting NF-κB, TLR4, and NOS/NO signaling pathways.

Bioactive peptides: an alternative therapeutic approach for cancer management

Cancer is still considered a lethal disease worldwide and the patients' quality of life is affected by major side effects of the treatments including post-surgery complications, chemo-, and radiation therapy. Recently, new therapeutic approaches were considered globally for increasing conventional cancer therapy efficacy and decreasing the adverse effects. Bioactive peptides obtained from plant and animal sources have drawn increased attention because of their potential as complementary therapy. This review presents a contemporary examination of bioactive peptides derived from natural origins with demonstrated anticancer, ant invasion, and immunomodulation properties. For example, peptides derived from common beans, chickpeas, wheat germ, and mung beans exhibited antiproliferative and toxic effects on cancer cells, favoring cell cycle arrest and apoptosis. On the other hand, peptides from marine sources showed the potential for inhibiting tumor growth and metastasis. In this review we will discuss these data highlighting the potential befits of these approaches and the need of further investigations to fully characterize their potential in clinics.

Natural compounds targeting nuclear receptors for effective cancer therapy

Human nuclear receptors (NRs) are a family of forty-eight transcription factors that modulate gene expression both spatially and temporally. Numerous biochemical, physiological, and pathological processes including cell survival, proliferation, differentiation, metabolism, immune modulation, development, reproduction, and aging are extensively orchestrated by different NRs. The involvement of dysregulated NRs and NR-mediated signaling pathways in driving cancer cell hallmarks has been thoroughly investigated. Targeting NRs has been one of the major focuses of drug development strategies for cancer interventions. Interestingly, rapid progress in molecular biology and drug screening reveals that the naturally occurring compounds are promising modern oncology drugs which are free of potentially inevitable repercussions that are associated with synthetic compounds. Therefore, the purpose of this review is to draw our attention to the potential therapeutic effects of various classes of natural compounds that target NRs such as phytochemicals, dietary components, venom constituents, royal jelly-derived compounds, and microbial derivatives in the establishment of novel and safe medications for cancer treatment. This review also emphasizes molecular mechanisms and signaling pathways that are leveraged to promote the anti-cancer effects of these natural compounds. We have also critically reviewed and assessed the advantages and limitations of current preclinical and clinical studies on this subject for cancer prophylaxis. This might subsequently pave the way for new paradigms in the discovery of drugs that target specific cancer types.

Differential expression of lysine acetylation proteins in gastric cancer treated with a new antitumor agent bioactive peptide chelate selenium

The method of anticancer bioactive peptide (ACBP) functionalized selenium particle (Se), which has enhanced anticancer activity, inhibited the growth of gastric cancer (GC) cells, and increased the ability of apoptosis in vitro, has been reported in previous studies. We used tandem mass spectrometry (TMT) labeling to construct a complete atlas of the acetylation-modified proteome in GC MKN-45 cells treated with ACBP-Se. The proteomics data database was searched and analyzed by bioinformatics: Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), functional enrichment, and protein-protein interaction network. Finally, we conducted a quantitative PRM analysis of the selected target-modified peptides. We identified 4,958 acetylation sites from 1,926 proteins in this research. Among these, 4,467 acetylation sites corresponding to 1,777 proteins were quantified. Based on the above data and standards, we found that in the ACBP-Se group vs. the control group, 297 sites were upregulated, and 665 sites were downregulated. We systematically assessed the proteins containing quantitative information sites, including protein annotation, functional classification, and functional enrichment, cluster analysis supported by functional enrichment, domain structures, and protein interaction networks. Finally, we evaluated differentially expressed lysine acetylation sites. We revealed that SHMT2 K200 and PGK1 K97 were the most critical acetylated non-histone proteins, which may have an essential role in ACBP-Se treatment. Here, we identified and quantified the lysine acetylation proteins in GC cells treated with ACBP-Se. The characterization of acetylation indicates that acetylated proteins might be pivotal in the biological process, molecular binding, and metabolic pathways of ACBP-Se treatment progress. Our findings provide a broad understanding of acetylation ACBP-Se treatment of GC, suggesting a potential application for molecular targeted therapy.

Bioactive Peptides: Potential Impact on the Treatment of Gastrointestinal Cancers

We have reviewed the potential use of bioactive peptides in the treatment of gastrointestinal (GI) malignancies, which are a significant cause of morbidity and mortality globally. Conventional therapies, such as surgery, chemotherapy, and radiotherapy, are associated with numerous side effects that may lead to longterm complications. Bioactive peptides are short-chain amino acids that can be extracted from natural sources or synthesized, and they have various potential health benefits, including anti-inflammatory, anti-hypertensive, antioxidant, antimicrobial, and anti-cancer properties. Bioactive peptides can be acquired from animal or plant sources, and can be classified based on their function, such as ACE-inhibiting, antimicrobial, and electrolyte- regulating peptides. Recent studies have demonstrated the promising role of bioactive peptides in tumor suppression, especially when combined with conventional therapies. In this study, we have reviewed the beneficial properties of bioactive peptides and their role in suppressing tumor activity. The mechanisms of bioactive peptides in tumor suppression are discussed. We have further reviewed the findings of preclinical and clinical studies that have investigated the application of bioactive peptides in the treatment of GI cancers. This review highlights the potential use of bioactive peptides as a promising treatment method for GI malignancies to increase the quality of life of GI cancer patients.

Anti-cancer peptides: their current trends in the development of peptide-based therapy and anti-tumor drugs

Human cancer remains a cause of high mortality throughout the world. The conventional methods and therapies currently employed for treatment are followed by moderate-to-severe side effects. They have not generated curative results due to the ineffectiveness of treatments. Besides, the associated high costs, technical requirements, and cytotoxicity further characterize their limitations. Due to relatively higher presidencies, bioactive peptides with anti-cancer attributes have recently become treatment choices within the therapeutic arsenal. The peptides act as potential anti-cancer agents explicitly targeting tumor cells while being less toxic to normal cells. The anti-cancer peptides are isolated from various natural sources, exhibit high selectivity and high penetration efficiency, and could be quickly restructured. The therapeutic benefits of compatible anti-cancer peptides have contributed to the significant expansion of cancer treatment; albeit, the mechanisms by which bioactive peptides inhibit the proliferation of tumor cells remain unclear. This review will provide a framework for assessing anti-cancer peptides' structural and functional aspects. It shall provide appropriate information on their mode of action to support and strengthen efforts to improve cancer prevention. The article will mention the therapeutic health benefits of anti-cancer peptides. Their importance in clinical studies is elaborated for reducing cancer incidences and developing sustainable treatment models.

Plant polypeptides: A review on extraction, isolation, bioactivities and prospects

The application of traditional Chinese medicine has a long history in China with unique advantages and functions. With the rapid development of separation and purification technologies, more and more polypeptide compounds with specific biological activity and medicinal value were isolated from natural plants. The plant polypeptides have a lot of biological activities, such as antitumor effect, antioxidize effect, antibacterial effect, hypoglycemic effect, blood pressure lowering effect, lipid-lowering effect, anti-fatigue effect, and so on. This review summarized the extraction method, purification method, biological activities, and prospects of plant polypeptides, providing a basis for further study of plant polypeptides.

The physiological activity of bioactive peptides obtained from meat and meat by-products

Meat and meat products constitute an important source of nutrients and play vital roles for growth, maintenance and repair of the body. In addition to the high quality of proteins, meat is also regarded as a major resource to produce bioactive peptides. Meat processing industry also produces by-products such as bones, blood and viscera, which could be further used for the production of bioactive compounds. In the physiological analysis, meat bioactive peptides have been reported to exert antioxidant, anti-hypertensive, anti-inflammatory, anti-microbial and antitumoral activities, which endow nutritional and functional value of meat. With the objective to exert the functional effect, the bioavailability should also be considered due to the degradation by digestion enzymes and the absorption process in intestinal mucosa. In this chapter, the general source, the enzymatic hydrolysis, the physiological effects as well as the bioavailability of bioactive peptides in meat are discussed.

ACBP suppresses the proliferation, migration, and invasion of colorectal cancer via targeting Wnt/beta-catenin signaling pathway

Anticancer bioactive peptide (ACBP), a novel bioactive peptide isolated from spleens of goats immunized with tumor extracts in our lab, can inhibit the proliferation of CRC in vitro and vivo. However, it remains unclear how the proliferation of CRC is inhibited by ACBP at the molecular level. Here, we provide evidences showing that ACBP significantly inhibits the expression of Wnt/β-catenin related genes (cyclin D1, met and c-myc) through pharmacotranscriptomic and qRT-PCR analysis in CRCs. Active β-catenin, a key protein within Wnt pathway, was compromised remarkably by ACBP in three CRCs, including HCT116, RKO and HT29. Thus nuclear accumulation of active β-catenin was retarded and finally lead to the decreased expression of oncogenes cyclin D1, met, and c-myc. In addition, we proved that active β-catenin reduction was mainly due to the inhibition of phospho-LRP6 and stimulation of phospho-β-catenin by ACBP. Based on the detection of Met and C-Myc in CRC tumor tissue without prior radiotherapy or chemotherapy, our results demonstrated that ACBP can act as a promising anticancer agent for CRC by targeting Wnt/β-catenin pathway, especially active β-catenin.

Cell-penetrating peptides in oncologic pharmacotherapy: A review

Cancer is the second leading cause of death in the world and its treatment is extremely challenging, mainly due to its complexity. Cell-Penetrating Peptides (CPPs) are peptides that can transport into the cell a wide variety of biologically active conjugates (or cargoes), and are, therefore, promising in the treatment and in the diagnosis of several types of cancer. Some notable examples are TAT and Penetratin, capable of penetrating the central nervous system (CNS) and, therefore, acting in cancers of this system, such as Glioblastoma Multiforme (GBM). These above-mentioned peptides, conjugated with traditional chemotherapeutic such as Doxorubicin (DOX) and Paclitaxel (PTX), have also been shown to induce apoptosis of breast and liver cancer cells, as well as in lung cancer cells, respectively. In other cancers, such as esophageal cancer, the attachment of Magainin 2 (MG2) to Bombesin (MG2B), another CPP, led to pronounced anticancer effects. Other examples are CopA3, that selectively decreased the viability of gastric cancer cells, and the CPP p28. Furthermore, in preclinical tests, the anti-tumor efficacy of this peptide was evaluated on human breast cancer, prostate cancer, ovarian cancer, and melanoma cells in vitro, leading to high expression of p53 and promoting cell cycle arrest. Despite the numerous in vitro and in vivo studies with promising results, and the increasing number of clinical trials using CPPs, few treatments reach the expected clinical efficacy. Usually, their clinical application is limited by its poor aqueous solubility, immunogenicity issues and dose-limiting toxicity. This review describes the most recent advances and innovations in the use of CPPs in several types of cancer, highlighting their crucial importance for various purposes, from therapeutic to diagnosis. Further clinical trials with these peptides are warranted to examine its effects on various types of cancer.

Effect of animal-sourced bioactive peptides on the in vitro development of mouse preantral follicles

The aim of this study was to investigate the effect of bioactive peptides (BAPT) from animal sources on the development of mouse preantral follicles in vitro. Preantral follicles were isolated and randomly divided into the following groups: an untreated group (control) and three groups supplemented with 20, 40 and 60 μg/mL BAPT, respectively. After establishing the in vitro follicle culture, the gene expression levels and hormone levels were quantified. After in vitro maturation, the developmental rates, reactive oxygen species (ROS) production levels and mitochondrial distributions of MII oocytes were investigated, followed by the analyses of embryonic developmental rates after in vitro fertilization.The results showed that BAPT promoted the growth of mouse preantral follicles. Notably, after 14 d of in vitro culture, the levels of 17 β-estradiol and progesterone were up-regulated with BAPT treatments. Moreover, the expression levels of Oct4, Bmp15, GDF9, FOXO3, Zp3, FOXL2, Inhibin alpha, SOD2, Catalase, GPx and Bcl-2 in the developing follicles were significantly up-regulated after BAPT treatments (P < 0.05), while BAPT significantly inhibited the expression levels of BAX (P < 0.05). Following BAPT treatments, the ROS production levels of MII oocytes were decreased while the mitochondrial distributions were significantly enhanced. Furthermore, increased maturation rates, fertilization and embryonic developmental rates were found in these BAPT-treated groups (P < 0.05).These results demonstrated that BAPT significantly improved the development of preantral follicles in vitro by reducing ROS-dependent cellular damages and by enhancing mitochondrial distributions, thereby promoting the further applications of animal-derived BAPT in biomedical research.

Effect of bioactive peptide on ram semen cryopreservation

This present study investigated the effect of bioactive peptide (BAPT) (BAPT) on the quality of ram semen during cryopreservation. Ram ejaculates were extended with Tris buffer supplemented with no antioxidants (as control group), 20 μg/mL BAPT (as BAPT20 group), 40 μg/mL BAPT (as BAPT40 group) and 60 μg/mL BAPT (as BAPT60 group). After cryopreservation, sperm quality including motility, vitality, the percentage of hypoosmotic swelling test (HOST)-positive spermatozoa and the percentage of intact acrosomes was assessed. Furthermore, the malondialdehyde (MDA) in seminal plasma and spermatozoa were analyzed, followed by the measurement of superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GSH-Px) levels in seminal plasma. After in vitro fertilization, the embryonic cleavage rates and development rates of different groups were analyzed to compare the developmental abilities of spermatozoa. The results showed that the post-thaw sperm motility was significantly higher in the BAPT60 group compared to those in the BAPT20, BAPT40 and control groups (P < 0.05). The percentage of live sperms significantly increased from 48.12 ± 2.35% for the BAPT20 group, 55.43 ± 2.16% for the BAPT40 group to 57.53 ± 3.15% for the BAPT60 group. The percentage of HOST-positive spermatozoa was significantly higher in the BAPT60 group than those in BAPT20, BAPT40 and control groups (P < 0.05). The MDA levels in seminal plasma and spermatozoa were significantly reduced with BAPT supplement (P < 0.05). Additionally, the SOD, CAT and GSH-Px levels in the BAPT experimental groups were significantly higher than those of the control group, which further indicated that BAPT significantly inhibit the reactive oxygen species (ROS) production during the cryopreservation of ram semen. Furthermore, the embryonic cleavage rates and development rates of the BAPT40 and BAPT60 groups were significantly increased in comparison with the BAPT20 and control groups (P < 0.05). In conclusion, BAPT improved the ram sperm quality via inhibiting the ROS production during cryopreservation, and could be applied as a promising supplement for ram semen cryopreservation.

Anticancer bioactive peptide combined with docetaxel and its mechanism in the treatment of breast cancer

Breast cancer remains a worldwide public-health issue. Novel drugs that increase the sensitivity and reduce the toxic side effects of chemotherapeutic agents are urgently required. The present study investigated the effect and mechanism of the short-term intermittent administration of an anticancer bioactive peptide (ACBP), docetaxel (DTX), ACBP combined with DTX (MIX) and ACBP combined with low dose DTX (L-MIX) to nude mice bearing human breast cancer tumors. The body weight, tumor length, tumor diameter, diet and water consumption of the tumor-bearing nude mice were calculated. The protein and mRNA expression levels of p53, p21 and Ki67 were detected via immunohistochemistry and reverse transcription-quantitative PCR, respectively. The results revealed that the activity level of each group of mice was consistent. However, the food and water consumption of the ACBP group was significantly increased compared with the NS group. Compared with the normal saline group, the tumor weights and volumes of the treatment groups were significantly decreased, indicating an inhibitory effect of the treatment. However, the MIX group exhibited lower tumor weights and volumes compared with the ACBP and DTX groups. Furthermore, no significant cell necrosis, edema or inflammatory cell infiltration was observed upon hematoxylin & eosin staining of the liver and spleen in all groups. The results also revealed that the p21, p53 and Ki67 protein and mRNA levels were decreased in the ACBP, DTX and MIX groups compared with the control group. Additionally, when compared with those in the MIX and L-MIX groups, the p21 and Ki67 protein, and p53 and Ki67 mRNA levels in the ACBP and DTX groups were significantly increased. The results suggested that the short-term intermittent use of ACBP alone had an inhibitory effect on tumor growth and improved the food and water consumption of tumor-bearing nude mice. Furthermore, the combination of ACBP and DTX reduced toxic side effects and the dosage requirement of drugs to achieve therapeutic effects on the tumor-bearing nude mice. Therefore, the antitumor effect of ACBP may be associated with the improvement of immune function in tumor-bearing nude mice and ACBP may serve an antitumor role via the p53-p21 signaling pathway in breast cancer.

iTRAQ‑based proteomics analysis of the therapeutic effects of combined anticancer bioactive peptides and oxaliplatin on gastric cancer cells

The combination of chemotherapeutic modalities may be more effective in treating gastric cancer compared with any modality alone. Previous studies have demonstrated that the combination of anticancer bioactive peptides (ACBP) and oxaliplatin (OXA) significantly inhibited the growth of the gastric cancer cell line MKN-45, promoted the apoptosis of MKN-45 cells, and caused an irreversible arrest of the MKN-45 cell cycle in the G2/M phase. In the present study, an isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomics technique was used to determine the effect of ACBP-OXA treatment on the proteomics profile of MKN-45 cells. Notably, a total of 6,210 proteins were detected. Proteins with a >1.2-fold change in expression (either up- or downregulation) and P<0.05 were considered to be differentially expressed. A total of 256 differentially expressed proteins were identified through alignments with different groups. Compared with the control group, MKN-45 cells treated with ACBP, OXA and ACBP-OXA exhibited 17 (10 up- and 7 downregulated), 111 (27 up- and 84 downregulated) and 128 (53 up- and 75 downregulated) differentially expressed proteins, respectively. Of the 256 differentially expressed proteins, 6 (TPX2, NUSAP1, TOP2A, YAP, MKi-67 and GPC4) were verified by the parallel reaction monitoring method, which revealed that TPX2, NUSAP1, TOP2A, YAP, MKi-67 and GPC4 expression decreased with ACBP-OXA treatment. The cellular localization, functional annotation and biological pathways of differentially expressed proteins were examined by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The results indicated that ACBP-OXA may act through the ribosome or the AMP-activated protein kinase (AMPK) signaling pathway, and the AMPK signaling pathway may be an important mediator of the inhibitory effects of ACBP-OXA on MKN-45 gastric cancer cells. In summary, iTRAQ-based proteomics analysis of the effect of ACBP-OXA on MKN-45 cells may guide future therapeutic strategies for gastric cancer. In addition, the present study may help provide new insights into the therapeutic role of combined ACBP and OXA in gastric cancer.

Bioactive Peptides Sensitize Cells to Anticancer Effects of Oxaliplatin in Human Colorectal Cancer Xenografts in Nude Mice

BACKGROUND

Despite new agent development and short-term benefits in patients with Colorectal Cancer (CRC), metastatic CRC cure rates have not improved due to high rates of oxaliplatin resistance and toxicity. There is an urgent need for effective tools to prevent and treat CRC and reduce morbidity and mortality of CRC patients. Exploring the effects of bioactive peptides on the antitumor to CRC was of vital importance to the clinical application.

OBJECTIVE

This study aimed to investigate the therapeutic impact of Anticancer Bioactive Peptides (ACBP) on anticancer effect of oxaliplatin (LOHP) in human colorectal cancer xenografts models in nude mice.

METHODS

HCT-116 cells were cultured in vitro via CCK-8 assays and the absorbance was measured at 450 nm. Apoptosis and cell cycle were assessed by Flow Cytometry (FCM) in vitro. HCT-116 human colorectal cancer cells inoculated subcutaneously in nude mice of treatment with PBS (GG), ACBP, LOHP, ACBP+LOHP (A+L) in vivo. The quality of life was assessed by dietary amount of nude mice, the weight of nude mice, inhibition rates, tumor weight and tumor volume. Immunohistochemistry and RT-qPCR method was conducted to determine the levels of apoptosisregulating proteins/genes in transplanted tumors.

RESULTS

ACBP induced substantial reductions in viable cell numbers and apoptosis of HCT116 cells in combined with LOHP in vitro. Compared with the control GG group, ACBP combined low dose oxaliplatin (U) group demonstrated significantly different tumor volume, the rate of apoptosis, the expression levels of Cyt-C, caspase-3,8,9 proteins and corresponding RNAs (P<0.05). The expression of pro-apoptotic proteins in the cytoplasm around the nucleus was significantly enhanced by ACBP. Short term intermittent use of ACBP alone indicted a certain inhibitory effect on tumor growth, and improve the quality of life of tumor bearing nude mice.

CONCLUSION

ACBP significantly increased the anti-cancer responses of low dose oxaliplatin (L-LOHP), thus, significantly improving the quality of life of tumor-bearing nude mice.

Advances in the Regulatory Effects of Bioactive Peptides on Metabolic Signaling Pathways in Tumor Cells

Changes in cell metabolism are an important feature of tumors that has always been an intense topic of study, particularly in regard to whether metabolic disorders are a cause or an effect of tumorigenesis. Studies have shown that the processes underlying metabolic changes in tumors involve the activation of protooncogenes and the inactivation of cancer suppressor genes, as well as changes in metabolic flux in cells due to the abnormal activation of signaling pathways that modulate metabolic enzymes and/or metabolic regulatory proteins at several levels, including transfer and posttranslational modification. Thus, the repair of abnormal metabolic pathways via intervention in the relevant tumor metabolic pathways that impact specific targets has become a new method of cancer prevention and treatment. Bioactive peptides, which have many biological functions, could specifically target malignant tumors. Their interaction with signal transduction molecules involved in the development and transference of tumors could regulate the relevant cell metabolic pathways and inhibit the development of tumors and/or accelerate apoptosis in tumor cells. In this review, several aspects of tumor suppression using bioactive peptides will be discussed and summarized, including the regulation of the PI3K/AKT/mTOR, AMPK, and STST3 signaling pathways, the modulation of the TRAIL death receptor signaling pathway, the regulation of aerobic glycolysis by PKM2, and the modulation of the NF-кB signaling pathway, to aid in the search for better and more specific antineoplastic drugs in the form of bioactive peptides.

Characterization and Identification of Cryptic Biopeptides in Carya illinoinensis (Wangenh K. Koch) Storage Proteins

The objective of this research was to identify and characterize the encoded peptides present in nut storage proteins of Carya illinoinensis. It was found, through in silico prediction, proteomic analysis, and MS spectrometry, that bioactive peptides were mainly found in albumin and glutelin fractions. Glutelin was the major fraction with ~53% of the nut storage proteins containing at least 21 peptides with different putative biological activities, including antihypertensives, antioxidants, immunomodulators, protease inhibitors, and inhibitors of cell cycle progression in cancer cells. Data showed that using 50 μg/mL tryptic digests of enriched peptides obtained from nut glutelins is able to induce up to 19% of apoptosis in both HeLa and CasKi cervical cancer cells. To our knowledge, this is the first report that shows the potential value of the nut-encoded peptides to be considered as adjuvants in cancer therapies.

Anticancer potential of bioactive peptides from animal sources (Review)

Cancer is the most common cause of human death worldwide. Conventional anticancer therapies, including chemotherapy and radiation, are associated with severe side effects and toxicities as well as low specificity. Peptides are rapidly being developed as potential anticancer agents that specifically target cancer cells and are less toxic to normal tissues, thus making them a better alternative for the prevention and management of cancer. Recent research has focused on anticancer peptides from natural animal sources, such as terrestrial mammals, marine animals, amphibians, and animal venoms. However, the mode of action by which bioactive peptides inhibit the proliferation of cancer cells remains unclear. In this review, we present the animal sources from which bioactive peptides with anticancer activity are derived and discuss multiple proposed mechanisms by which these peptides exert cytotoxic effects against cancer cells.

New bioactive peptide reduces the toxicity of chemotherapy drugs and increases drug sensitivity

Anticancer bioactive peptide (ACBP) is extracted from normal goat spleens and exhibits antitumor activity alone and in combination with low cisplatin doses to achieve antitumor efficacy similar to higher cisplatin doses via sustained medication modes. In the present study, we investigated whether elevated levels of induced or normal ACBP in MKN‑45 gastric cancer (GC) cells may reduce their toxicity to oxaliplatin (L‑OHP) in a dose‑dependent manner. The growth inhibition rate (IR), morphological changes and gene expression were examined in MKN‑45 GC cells. Compared with normal ACBP, induced ACBP alone significantly enhanced the anticancer activity of L‑OHP‑mediated apoptosis and reduced the amount and side‑effects of L‑OHP (P<0.05). The inhibition of cancer cell growth at high concentrations of induced ACBP and L‑OHP was significantly more effective than at low concentrations. In addition, for the first time, we examined the potential of a combination of induced ACBP and L‑OHP to increase L‑OHP sensitivity in human gastric carcinoma xenograft tumors. Nude mice were implanted with human gastric carcinoma MKN‑45 cells and treated with an intraperitoneal injection of 0.5 ml of normal saline, 30 µg/ml ACBP, 20 µg/ml L‑OHP or 30 µg/ml ACBP + 20 µg/ml L‑OHP [combination of anticancer bioactive peptide and oxaliplatin (A+L)] via the tail vein twice a week. In vivo short‑term intermittent use of induced ACBP alone significantly inhibited MKN‑45 tumor growth. The combination of induced ACBP and L‑OHP also significantly improved the quality of life of the nude mice and reduced the toxicity of L‑OHP. Based on flow cytometry and gene expression analyses, A+L significantly increased the proportion of cells in the G2/M phase (P<0.05) relative to ACBP or L‑OHP alone, and short‑term intraperitoneal injection of ACBP increased the sensitizing effect of L‑OHP. Collectively, these results suggest that high levels of induced ACBP in combination with L‑OHP via a short‑term intermittent medication mode could be a useful clinical therapeutic strategy for GC.

Anticancer bioactive peptide-3 inhibits human gastric cancer growth by targeting miR-338-5p

BACKGROUND

Cancer incidence and mortality have been increasing in China, making cancer the leading cause of death since 2010 and a major public health concern in the country. Cancer stem cells have been studied in relation to the treatment of different malignancies, including gastric cancer. Anticancer bioactive peptide-3 (ACBP-3) can induce the apoptosis of gastric cancer stem cells (GCSCs) and reduce their tumorigenicity. In the present study, for the first time, we used a miRNA microarray and bioinformatics analysis to identify differentially expressed miRNAs in ACBP-3-treated GCSCs and GCSC-derived tumors in a xenograft model and functionally verified the identified miRNAs. miR-338-5p was selected based on its significant upregulation by ACBP-3 both in cultured GCSCs and in tumor tissues.

RESULTS

miR-338-5p was downregulated in GCSCs compared with normal gastric epithelial cells, and the ectopic restoration of miR-338-5p expression in GCSCs inhibited cell proliferation and induced apoptosis, which correlated with the upregulation of the pro-apoptotic Bcl-2 proteins BAK and BIM. We also found that ACBP-3-treated GCSCs could respond to lower effective doses of cisplatin (DDP) or 5-fluorouracil (5-FU), possibly because ACBP-3 induced the expression of miR-338-5p and the BAK and BIM proteins and promoted GCSC apoptosis.

CONCLUSIONS

Our data indicate that miR-338-5p is part of an important pathway for the inhibition of human gastric cancer stem cell proliferation by ACBP-3 combined with chemotherapeutics. ACBP-3 could suppress GCSC proliferation and lower the required effective dose of cisplatin or 5-fluorouracil. Therefore, this study provides not only further evidence for the remarkable anti-tumor effect of ACBP-3 but also a possible new approach for the development of GCSC-targeting therapies.

Anticancer bioactive peptides suppress human colorectal tumor cell growth and induce apoptosis via modulating the PARP-p53-Mcl-1 signaling pathway

AIM

We have reported novel anticancer bioactive peptides (ACBPs) that show tumor-suppressive activities in human gastric cancer, leukemia, nasopharyngeal cancer, and gallbladder cancer. In this study, we investigated the effects of ACBPs on human colorectal cancer and the underlying mechanisms.

METHODS

Cell growth and apoptosis of human colorectal tumor cell line HCT116 were measured using cell proliferation assay and flow cytometry, respectively. The expression levels of PARP, p53 and Mcl1A were assessed with Western blotting and immunohistochemistry. For evaluation of the in vivo antitumor activity of ACBPs, HCT116 xenograft nude mice were treated with ACBPs (35 μg/mL, ip) for 10 days.

RESULTS

Treatment of HCT116 cells with ACBPs (35 μg/mL) for 4-6 days significantly inhibited the cell growth. Furthermore, treatment of HCT116 cells with ACBPs (35 μg/mL) for 6-12 h significantly enhanced UV-induced apoptosis, increased the expression of PARP and p53, and decreased the expression of Mcl-1. Administration of ACBPs did not change the body weight of HCT116 xenograft nude mice, but decreased the tumor growth by approximately 43%, and increased the expression of PARP and p53, and decreased the expression of Mcl-1 in xenograft mouse tumor tissues.

CONCLUSION

Administration of ACBPs inhibits human colorectal tumor cell growth and induces apoptosis in vitro and in vivo through modulating the PARP-p53-Mcl-1 signaling pathway.

Mitotic catastrophe and cancer drug resistance: A link that must to be broken

An increased tendency of genomic alterations during the life cycle of cells leads to genomic instability, which is a major driving force for tumorigenesis. A considerable fraction of tumor cells are tetraploid or aneuploid, which renders them intrinsically susceptible to mitotic aberrations, and hence, are particularly sensitive to the induction of mitotic catastrophe. Resistance to cell death is also closely linked to genomic instability, as it enables malignant cells to expand even in a stressful environment. Currently it is known that cells can die via multiple mechanisms. Mitotic catastrophe represents a step preceding apoptosis or necrosis, depending on the expression and/or proper function of several proteins. Mitotic catastrophe was proposed to be an onco-suppressive mechanism and the evasion of mitotic catastrophe constitutes one of the gateways to cancer development. Thus, stimulation of mitotic catastrophe appears to be a promising strategy in cancer treatment. Indeed, several chemotherapeutic drugs are currently used at concentrations that induce apoptosis irrespective of the cell cycle phase, yet are very efficient at triggering mitotic catastrophe at lower doses, significantly limiting side effects. In the present review we summarize current data concerning the role of mitotic catastrophe in cancer drug resistance and discuss novel strategies to break this link.

Delivery of therapeutics using nanocarriers for targeting cancer cells and cancer stem cells

Development of cancer resistance, cancer relapse and metastasis are attributed to the presence of cancer stem cells (CSCs). Eradication of this subpopulation has been shown to increase life expectancy of patients. Since the discovery of CSCs a decade ago, several strategies have been devised to specifically target them but with limited success. Nanocarriers have recently been employed to deliver anti-CSC therapeutics for reducing the population of CSCs at the tumor site with great success. This review discusses the different therapeutic strategies that have been employed using nanocarriers, their advantages, success in targeting CSCs and the challenges that are to be overcome. Exploiting this new modality of cancer treatment in the coming decade may improve outcomes profoundly with promise of effective treatment response and reducing relapse and metastasis.

Bioactive peptides of animal origin: a review

Bioactive peptides are specific protein fragments which, above and beyond their nutritional capabilities, have a positive impact on the body's function or condition which may ultimately influence health. Although, inactive within the sequence of the parent proteins, these peptides can be released during proteolysis or fermentation and play an important role in human health by affecting the digestive, endocrine, cardiovascular, immune and nervous systems. Several peptides that are released in vitro or in vivo from animal proteins have been attributed to different health effects, including antimicrobial properties, blood pressure-lowering (ACE inhibitory) effects, cholesterol-lowering ability, antithrombotic and antioxidant activities, opioid activities, enhancement of mineral absorption and/or bioavailability, cytomodulatory and immunomodulatory effects, antiobesity, and anti-genotoxic activity. Several functional foods based on the bioactivities of these peptides with scientifically evidenced health claims are already on the market or under development by food companies. Consumer's increasing interest in these products has given an impetus to the food industry and scientific sector who are continuously exploring the possibilities for the development of new functional products based on these peptides. In this review, we describe above stated properties of bioactive peptides of animal origin.