title: Nanofabrication of methylglyoxal with chitosan biopolymer: a potential tool for enhancement of its anticancer effect.
abstract: OBJECTIVE
  The normal metabolite methylglyoxal (MG) specifically kills cancer cells by inhibiting glycolysis and mitochondrial respiration without much adverse effect upon normal cells. Though the anticancer property of MG is well documented, its gradual enzymatic degradation in vivo has prompted interest in developing a nanoparticulate drug delivery system to protect it and also to enhance its efficacy.
  
  
  METHODS
  MG-conjugated chitosan nanoparticles (Nano-MG) were prepared by conjugating the carbonyl group of MG with the amino group of chitosan polymer (Schiff's base formation). Nano-MG were characterized in detail using the dynamic light scattering method, zeta potential measurement, Fourier transform infrared spectroscopy, and transmission electron microscopic analysis. Amount of MG anchored to Nano-MG, stability of Nano-MG, and in vitro release of MG from Nano-MG were estimated spectrophotometrically. Ehrlich ascites carcinoma (EAC) cells, human breast cancer cell line HBL-100, and lung epithelial adenocarcinoma cell line A549 were used as test systems to compare Nano-MG with bare MG in vitro. Cytotoxicity to EAC cells was evaluated by the trypan blue dye exclusion test, and cell viability of HBL-100 and A549 cells were studied using 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis of HBL-100 cells was assessed by flow cytometry and confocal microscopy. In vivo studies were performed on both EAC cells inoculated and also in sarcoma-180-induced solid tumor-bearing Swiss albino mice to assess the anticancer activity of Nano-MG in comparison to bare MG with varying doses, times, and administrative routes.
  
  
  RESULTS
  Fourier transform infrared spectroscopy revealed the presence of imine groups in Nano-MG due to conjugation of the amino group of chitosan and carbonyl group of MG with diameters of nanoparticles ranging from 50-100 nm. The zeta potential of Nano-MG was +21 mV and they contained approximately 100 μg of MG in 1 mL of solution. In vitro studies with Nano-MG showed higher cytotoxicity and enhanced rate of apoptosis in the HBL-100 cell line in comparison with bare MG, but no detrimental effect on normal mouse myoblast cell line C2C12 at the concerned doses. Studies with EAC cells also showed increased cell death of nearly 1.5 times. Nano-MG had similar cytotoxic effects on A549 cells. In vivo studies further demonstrated the efficacy of Nano-MG over bare MG and found them to be about 400 times more potent in EAC-bearing mice and nearly 80 times more effective in sarcoma-180-bearing mice. Administration of ascorbic acid and creatine during in vivo treatments augmented the anticancer effect of Nano-MG.
  
  
  CONCLUSIONS
  The results clearly indicate that Nano-MG may constitute a promising tool in anticancer therapeutics in the near future.
authors.affiliation: Department of Biophysics, Bose Institute, Kolkata, India.
authors.forename: Aparajita
authors.initials: A
authors.lastname: Pal
authors.affiliation: Department of Biophysics, Bose Institute, Kolkata, India.
authors.forename: Dipa
authors.initials: D
authors.lastname: Talukdar
authors.affiliation: Department of Biophysics, Bose Institute, Kolkata, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Roy
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India.
authors.forename: Subhankar
authors.initials: S
authors.lastname: Ray
authors.affiliation: Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Asish
authors.initials: A
authors.lastname: Mallick
authors.affiliation: Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Chitra
authors.initials: C
authors.lastname: Mandal
authors.affiliation: Department of Biophysics, Bose Institute, Kolkata, India.
authors.forename: Manju
authors.initials: M
authors.lastname: Ray
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000633:toxicity; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry / Q000633:toxicity; D006801:Humans; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity; D036103:Nanotechnology; D011765:Pyruvaldehyde / Q000737:chemistry / Q000633:toxicity
chemical_list: D000970:Antineoplastic Agents; D011765:Pyruvaldehyde; D048271:Chitosan
keywords: A549; C2C12; EAC; HBL-100; anticancer agent; apoptosis; nano-methylglyoxal; sarcoma-180