title: Structure based design and synthesis of peptide inhibitor of human LOX-12: in vitro and in vivo analysis of a novel therapeutic agent for breast cancer.
abstract: Human breast cancer cell proliferation involves a complex interaction between growth factors, steroid hormones and peptide hormones. The interaction of growth factors, such as epidermal growth factor (EGF), with their receptors on breast cancer cells can lead to the hydrolysis of phospholipids and release of fatty acid such as arachidonic acid, which can be further metabolized by cyclooxygenase (COX) and lipoxygenase (LOX) pathways to produce prostaglandins. The high concentration of prostaglandins has been associated with chronic inflammatory diseases and several types of human cancers. This is due to the over expression COX, LOX and other inflammatory enzymes. Ten peptides were designed and synthesized by solid phase peptide synthesis and analyzed in vitro for enzyme inhibition. Out of these peptides, YWCS had shown significant inhibitory effects. The dissociation constant (K(D)) was determined by surface plasmon resonance (SPR) analysis and was found to be 3.39 × 10(-8) M and 8.6 × 10(-8) M for YWCS and baicalein (positive control), respectively. The kinetic constant Ki was 72.45 × 10(-7) M as determined by kinetic assay. The peptide significantly reduced the cell viability of estrogen positive MCF-7 and estrogen negative MDA-MB-231 cell line with the half maximal concentration (IC(50)) of 75 µM and 400 µM, respectively. The peptide also induced 49.8% and 20.8% apoptosis in breast cancer cells MCF-7 and MDA-MB-231, respectively. The YWCS was also found to be least hemolytic at a concentration of 358 µM. In vivo studies had shown that the peptide significantly inhibits tumor growth in mice (p<0.017). This peptide can be used as a lead compound and complement for ongoing efforts to develop differentiation therapies for breast cancer.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Abhay Kumar
authors.initials: AK
authors.lastname: Singh
authors.forename: Ratnakar
authors.initials: R
authors.lastname: Singh
authors.forename: Farhat
authors.initials: F
authors.lastname: Naz
authors.forename: Shyam Singh
authors.initials: SS
authors.lastname: Chauhan
authors.forename: Amit
authors.initials: A
authors.lastname: Dinda
authors.forename: Abhay Anand
authors.initials: AA
authors.lastname: Shukla
authors.forename: Kamaldeep
authors.initials: K
authors.lastname: Gill
authors.forename: Vaishali
authors.initials: V
authors.lastname: Kapoor
authors.forename: Sharmistha
authors.initials: S
authors.lastname: Dey
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D001092:Arachidonate 12-Lipoxygenase / Q000737:chemistry*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology; D045744:Cell Line, Tumor; D002470:Cell Survival; D002626:Chemistry, Pharmaceutical / Q000379:methods; D015195:Drug Design; D004354:Drug Screening Assays, Antitumor; D004967:Estrogens / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D016859:Lipoxygenase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry*; D015674:Mammary Neoplasms, Animal / Q000188:drug therapy / Q000201:enzymology; D051379:Mice; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D004967:Estrogens; D016859:Lipoxygenase Inhibitors; D010455:Peptides; D011994:Recombinant Proteins; D001092:Arachidonate 12-Lipoxygenase