The soy-derived peptide Vglycin inhibits the growth of colon cancer cells in vitro and in vivo

Vglycin, a novel natural polypeptide isolated from pea seeds, possesses antidiabetic properties. Our previous studies have shown that Vglycin can induce the differentiation of human colon adenocarcinoma cells. We aimed to determine the anticancer activity of Vglycin against colon cancer cells and to elucidate related apoptosis-inducing mechanisms. Treatment with purified Vglycin significantly reduced growth, viability, and colony formation of CT-26, SW480, and NCL-H716 colon cancer cells in a dose-dependent manner while down-regulating the expression of proliferating cell nuclear antigen. Mouse xenograft studies showed a 38% inhibition of colon cancer growth in mice treated with Vglycin (20 mg/kg/day) at day 21. Furthermore, the potential mechanisms involved in Vglycin-induced cell apoptosis were examined using cell cycle studies, ultrastructural examination, as well as apoptosis-associated pathway analysis. The results showed that Vglycin significantly promoted apoptosis and G1/S phase cell cycle arrest. As revealed by Western blot, the expression of CDK2 and Cyclin D1 was down-regulated in all three Vglycin-treated colon cancer cells, indicating that the CDK2/Cyclin D1 cell cycle pathway involved in the initiation and progression of colon cancer. Moreover, the inhibition of Vglycin-induced cell proliferation in colon cancer cells was accompanied by alteration of the expression levels of the apoptosis-related proteins Bax, Bcl-2 and Mcl-1, and an increase of caspase-3 activity. Together, our results suggest that Vglycin may be another plant-derived peptide that suppresses colon cancer, supporting the continued investigation of Vglycin as therapeutic agent for colon cancer. Impact statement The antidiabetic properties and the capability of inducing differentiation of human colon adenocarcinoma cells of Vglycin have been reported in our previous studies. However, the anticancer potential of Vglycin on colon cancer cells and its possible related mechanisms were still unknown. In this study, we found that Vglycin could reduce growth, viability, and colony formation or colony size of CT-26, SW480, and NCL-H716 colon cancer cells. Moreover, Vglycin decreased tumor volume by 38% in xenograft mice transplanted with CT-26 cells. The mechanisms of these phenomena may be due to the down-regulated CDK2 and Cyclin D1, G1/S phase cell cycle arrest, and the dysregulated expression of Bax, Bcl-2, and Mcl-1. The findings highlight the anticancer potential of Vglycin against colon cancer cells, and suggest Vglycin may be another colon cancer potential suppressive component of plant-derived peptides.

[1]  Yupeng Cheng,et al.  Lunasin suppresses the migration and invasion of breast cancer cells by inhibiting matrix metalloproteinase-2/-9 via the FAK/Akt/ERK and NF-κB signaling pathways. , 2016, Oncology reports.

[2]  L. Galluzzi,et al.  Caspases Connect Cell-Death Signaling to Organismal Homeostasis. , 2016, Immunity.

[3]  H. Schulze‐Bergkamen,et al.  Low levels of Caspase-3 predict favourable response to 5FU-based chemotherapy in advanced colorectal cancer: Caspase-3 inhibition as a therapeutic approach , 2016, Cell Death and Disease.

[4]  Tzong-Ming Shieh,et al.  ZEB1 as an indicator of tumor recurrence for areca quid chewing-associated oral squamous cell carcinomas. , 2015, Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology.

[5]  K. Leung,et al.  Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinoma , 2015, Molecular medicine reports.

[6]  D. Fuhrer,et al.  Cell death induction by the BH3 mimetic GX15-070 in thyroid carcinoma cells , 2015, Journal of Experimental & Clinical Cancer Research.

[7]  H. Kadir,et al.  Elephantopus scaber induces apoptosis through ROS-dependent mitochondrial signaling pathway in HCT116 human colorectal carcinoma cells. , 2015, Journal of ethnopharmacology.

[8]  H. Karimian,et al.  The Chemopotential Effect of Annona muricata Leaves against Azoxymethane-Induced Colonic Aberrant Crypt Foci in Rats and the Apoptotic Effect of Acetogenin Annomuricin E in HT-29 Cells: A Bioassay-Guided Approach , 2015, PloS one.

[9]  A. Keating,et al.  Potent and specific peptide inhibitors of human pro-survival protein Bcl-xL. , 2015, Journal of molecular biology.

[10]  K. Yaddanapudi,et al.  The soybean-derived peptide lunasin inhibits non-small cell lung cancer cell proliferation by suppressing phosphorylation of the retinoblastoma protein , 2014, Oncotarget.

[11]  Robert Winkler,et al.  Preventive and therapeutic potential of peptides from cereals against cancer. , 2014, Journal of proteomics.

[12]  Xuebing Yan,et al.  CDK2-AP1 inhibits growth of breast cancer cells by regulating cell cycle and increasing docetaxel sensitivity in vivo and in vitro , 2014, Cancer Cell International.

[13]  C. Ostenson,et al.  Oral administration of soybean peptide Vglycin normalizes fasting glucose and restores impaired pancreatic function in Type 2 diabetic Wistar rats. , 2014, The Journal of nutritional biochemistry.

[14]  C. Billard.  BH3 Mimetics: Status of the Field and New Developments , 2013, Molecular Cancer Therapeutics.

[15]  J. Opferman,et al.  Delving deeper: MCL-1's contributions to normal and cancer biology. , 2013, Trends in cell biology.

[16]  C. Billard.  BH 3 Mimetics : Status of the Field and New Developments , 2013 .

[17]  Sam K C Chang,et al.  Effect of black soybean extract on the suppression of the proliferation of human AGS gastric cancer cells via the induction of apoptosis. , 2011, Journal of agricultural and food chemistry.

[18]  V. Dia,et al.  Lunasin promotes apoptosis in human colon cancer cells by mitochondrial pathway activation and induction of nuclear clusterin expression. , 2010, Cancer letters.

[19]  Jae Ho Park,et al.  Complementary Roles in Cancer Prevention: Protease Inhibitor Makes the Cancer Preventive Peptide Lunasin Bioavailable , 2010, PloS one.

[20]  B. Hernández-Ledesma,et al.  Lunasin, a novel seed peptide for cancer prevention , 2009, Peptides.

[21]  N. Danial,et al.  BCL-2 Family Proteins: Critical Checkpoints of Apoptotic Cell Death , 2007, Clinical Cancer Research.

[22]  H. Hass,et al.  Studies on p53, BAX and Bcl-2 protein expression and microsatellite instability in stage III (UICC) colon cancer treated by adjuvant chemotherapy: major prognostic impact of proapoptotic BAX , 2007, British Journal of Cancer.

[23]  G. Stark,et al.  Control of the G2/M transition , 2006, Molecular biotechnology.

[24]  S. Friedman,et al.  Cyclin-Dependent Kinase Inhibition by the KLF6 Tumor Suppressor Protein through Interaction with Cyclin D1 , 2004, Cancer Research.

[25]  C. Hasler,et al.  The anticarcinogenic potential of soybean lectin and lunasin. , 2003, Nutrition reviews.

[26]  K. Vermeulen,et al.  The cell cycle: a review of regulation, deregulation and therapeutic targets in cancer , 2003, Cell proliferation.

[27]  H. Irving.  Disorders in cell circuitry during multistage carcinogenesis: the role of homeostasis , 2000 .

[28]  Y. Lazebnik,et al.  Caspases: enemies within. , 1998, Science.

[29]  Emma Lees,et al.  Mammary hyperplasia and carcinoma in MMTV-cyclin D1 transgenic mice , 1994, Nature.

[30]  H. Ludwig,et al.  The prognostic significance of proliferating cell nuclear antigen, epidermal growth factor receptor, and mdr gene expression in colorectal cancer , 1993, Cancer.