Qiang Li1, Yoshiharu Tanaka2, Yasukazu Saitoh3, Hiroshi Tanaka1, Nobuhiko Miwa4. 1. Department of Radiological Technology, Faculty of Health Sciences, Butsuryo College of Osaka, Otorikitamachi 3-33, Nishi-ku, Sakai, Osaka 593-8328, Japan. 2. Laboratory of Biology and Genetics, Faculty of Liberal Arts and Sciences, Osaka Prefecture University, Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan. 3. Laboratory of Bioscience & Biotechnology for Cell Function Control, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Nanatsuka 562, Shobara, Hiroshima 727-0023, Japan. 4. Department of Radiological Technology, Faculty of Health Sciences, Butsuryo College of Osaka, Otorikitamachi 3-33, Nishi-ku, Sakai, Osaka 593-8328, Japan. Electronic address: miwa@butsuryo.ac.jp.
Abstract
AIMS: To explore the carcinostatic effects of platinum nanocolloid (Pt-nc) combined with gamma rays on human esophageal squamous cell carcinoma (ESCC). MAIN METHODS: ESCC-derived KYSE-70 cells were treated with various concentrations of Pt-nc and/or gamma irradiation, and subsequently cultured in phenol red free DMEM with 10% FBS for 48 h. The proliferative status of the KYSE-70 cells was evaluated using trypan blue dye exclusion and WST-8 assays. Cellular and nucleic morphological aspects were evaluated using crystal violet and Hoechst 33342 stainings, respectively. Radiosensitivity was quantified by a cell viability assay, and the activated form of caspase-3, a characteristic apoptosis-related protein, was detected by Western blotting. KEY FINDINGS: Although single treatment with either Pt-nc or gamma irradiation could slightly inhibit the growth of the KYSE-70 cells, their combination exerted remarkable carcinostatic effects in a manner dependent on either Pt-nc concentrations or gamma ray doses, compared with the effect of each treatment alone (p<0.05). By fluorescence micrographic observation, the KYSE-70 cells that were treated with Pt-nc and subsequently irradiated with gamma rays, were shown to undergo distinct apoptotic morphological changes. The carcinostatic effect of gamma rays at 7 Gy without Pt-nc was approximately equal to that when 3-Gy irradiation was combined with 100 ppm Pt-nc or that 5-Gy irradiation was combined with 50 ppm Pt-nc. SIGNIFICANCE: Pt-nc in combination with gamma rays may exert a cooperative effect through platinum- or gamma ray-induced apoptosis resulting in the inhibition of growth of cancer cells, while concurrently enabling the lowering of the radiative dose.
AIMS: To explore the carcinostatic effects of platinum nanocolloid (Pt-nc) combined with gamma rays on humanesophageal squamous cell carcinoma (ESCC). MAIN METHODS: ESCC-derived KYSE-70 cells were treated with various concentrations of Pt-nc and/or gamma irradiation, and subsequently cultured in phenol red free DMEM with 10% FBS for 48 h. The proliferative status of the KYSE-70 cells was evaluated using trypan blue dye exclusion and WST-8 assays. Cellular and nucleic morphological aspects were evaluated using crystal violet and Hoechst 33342 stainings, respectively. Radiosensitivity was quantified by a cell viability assay, and the activated form of caspase-3, a characteristic apoptosis-related protein, was detected by Western blotting. KEY FINDINGS: Although single treatment with either Pt-nc or gamma irradiation could slightly inhibit the growth of the KYSE-70 cells, their combination exerted remarkable carcinostatic effects in a manner dependent on either Pt-nc concentrations or gamma ray doses, compared with the effect of each treatment alone (p<0.05). By fluorescence micrographic observation, the KYSE-70 cells that were treated with Pt-nc and subsequently irradiated with gamma rays, were shown to undergo distinct apoptotic morphological changes. The carcinostatic effect of gamma rays at 7 Gy without Pt-nc was approximately equal to that when 3-Gy irradiation was combined with 100 ppm Pt-nc or that 5-Gy irradiation was combined with 50 ppm Pt-nc. SIGNIFICANCE: Pt-nc in combination with gamma rays may exert a cooperative effect through platinum- or gamma ray-induced apoptosis resulting in the inhibition of growth of cancer cells, while concurrently enabling the lowering of the radiative dose.