title: Growth inhibition effect of HMME-mediated PDT on hepatocellular carcinoma HepG2 cells.
abstract: Photodynamic therapy (PDT) is considered a promising new strategy for liver cancer treatment. Three elements of PDT--optical output power, irradiation time, and photosensitizer concentration--play important roles in promoting cell death. This research aimed to characterize the effects of hematoporphyrin monomethyl ether (HMME)-based PDT on hepatocellular carcinoma cells HepG2 and thus elucidate the relationship between cell death and the three elements mentioned earlier. Furthermore, in this study, we present a parameter that represents the cumulative effects of these elements. The accumulation of HMME in HepG2 cells was observed by fluorescence microscopy. The absorption spectrum of HMME was detected using fluorescence spectral analysis. The viability of the treated cells was determined using the MTT assay, and cell apoptosis was evaluated using flow cytometry. We found that the fluorescence intensity was positively correlated with the incubation time for up to 2 h. The cell growth inhibition rate was significantly high and gradually increased with increasing concentrations of HMME or increasing light intensity, which was calculated as optical output power × irradiation time. Further analysis revealed an e-exponential decay of the cell survival rate to the product of the HMME concentration and the light intensity. We defined the product as parameter B (B = optical output power × irradiation time × HMME concentration). Similarly, the rate of cell apoptosis showed roughly e-exponential growth to parameter B. In conclusion, HMME-mediated PDT can significantly kill HepG2 cells, and the killing effect was related to the cumulative effects of the optical output power, the irradiation time, and the HMME concentration. Therefore, the newly defined parameter B, as a comprehensive physical quantity, may be of great significance for the regulation of light and photosensitizer according to patient-specific conditions in clinical practice.
authors.affiliation: Department of Digestion Medicine, The Fourth Affiliated Hospital of Harbin Medical University, No. 37, Yiyuan Street, Harbin, Heilongjiang, 150001, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Liu
authors.forename: Yuanjian
authors.initials: Y
authors.lastname: Song
authors.forename: Limin
authors.initials: L
authors.lastname: Ma
authors.forename: Lixin
authors.initials: L
authors.lastname: Zang
authors.forename: Lili
authors.initials: L
authors.lastname: Tao
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jiwu
authors.initials: J
authors.lastname: Han
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005434:Flow Cytometry; D006415:Hematoporphyrins / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D056945:Hep G2 Cells; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology / Q000627:therapeutic use; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D006415:Hematoporphyrins; D017319:Photosensitizing Agents; C494379:hematoporphyrin monomethyl ether