title: Indocyanine green loaded liposome nanocarriers for photodynamic therapy using human triple negative breast cancer cells.
abstract: BACKGROUND
  The goal of the current research is to evaluate the potential of photodynamic therapy (PDT) in the treatment of triple negative breast cancer (TNBC) with the development of a theranostic thermosensitive liposome platform to deliver indocyanine green (ICG) as the near-infrared (NIR) photosensitizer excited by an 808 nm diode laser.
  
  
  METHODS
  In the PDT protocol, an optimized thermosensitive liposome formulation is investigated to formulate ICG as the photosensitizer, which is exited by laser light at the wavelength of 808 nm delivered by a fiber-coupled laser system. ICG in both free solution and thermosensitive liposomal formulation were evaluated as the NIR photosensitizer and compared in the PDT treatment on a panel of triple negative breast cancer cell lines along with the nontumorigenic mammary epithelial cell line MCF-10A. In addition to cytotoxicity, and clonogenic survival assessment, the role of DNA double strand break damage was evaluated.
  
  
  RESULTS
  Both MTT and clonogenic assays revealed that PDT using ICG inhibited the growth of several TNBC cell lines as well as the non-tumorigenic human breast epithelial cell line MCF-10A; and the liposomal formulation of ICG did not compromise the in vitro treatment potency, though free ICG performed slightly more effective in certain cell lines, but was not statistically significant. Cell viability was dose dependent in regards to ICG concentration and irradiation energy. Interestingly, PDT using the described protocol was more potent to inhibit the growth of MDA-MB-468 and HCC-1806 cells, coinciding with the observation that these cells are more sensitive toward DNA damaging agents. In comparison, cell lines HCC-70, BT-549, and MCF-10A were found to have less of an inhibitory effect. Furthermore, substantial DNA double strand breaks (DSBs) were observed 30 min after the PDT treatment via a γ-H2AX staining assay. PDT induced DNA damage has the potential to lead to mutagenicity, which may have various responses depending on the repair capabilities of the cells.
  
  
  CONCLUSIONS
  Our results suggest that PDT using indocyanine green loaded liposomes were effective in inhibiting tumor cell growth to varying extents with higher responses observed for MDA-MB-468 and HCC-1806 cells.
authors.affiliation: Drug Delivery Laboratory, Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, 3001 Mercer University Drive, Atlanta, GA 30341, United States.
authors.forename: Colby S
authors.initials: CS
authors.lastname: Shemesh
authors.affiliation: Department of Radiation Oncology, Emory University School of Medicine, 1365 Clifton Road Northeast, Atlanta, GA 30322, United States.
authors.forename: Claire W
authors.initials: CW
authors.lastname: Hardy
authors.affiliation: Department of Radiation Oncology, Emory University School of Medicine, 1365 Clifton Road Northeast, Atlanta, GA 30322, United States.
authors.forename: David S
authors.initials: DS
authors.lastname: Yu
authors.affiliation: Drug Delivery Laboratory, Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, 3001 Mercer University Drive, Atlanta, GA 30341, United States.
authors.forename: Brian
authors.initials: B
authors.lastname: Fernandez
authors.affiliation: Drug Delivery Laboratory, Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, 3001 Mercer University Drive, Atlanta, GA 30341, United States. Electronic address: zhang_h@mercer.edu.
authors.forename: Hailing
authors.initials: H
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004058:Diffusion; D006801:Humans; D007208:Indocyanine Green / Q000008:administration & dosage* / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D053769:Nanocapsules / Q000008:administration & dosage / Q000737:chemistry* / Q000648:ultrastructure; D010778:Photochemotherapy / Q000379:methods*; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage / Q000737:chemistry; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*
chemical_list: D008081:Liposomes; D053769:Nanocapsules; D011838:Radiation-Sensitizing Agents; D007208:Indocyanine Green
keywords: DNA damage; Indocyanine green (ICG); Photodynamic therapy (PDT); Thermosensitive liposome; Triple negative breast cancer (TNBC)