Abstract 3549: RUNX3 is a biomarker for determining sensitivity to pheophorbide a-photodynamic therapy in human oral squamous cell carcinoma.

Abstract

Background & Objective: Photodynamic therapy (PDT) with photosensitizer is one of the promising modalities for cancer treatment. For clinical use of PDT, the screening process for sensitive cancers to PDT should be preceded. For this, we investigated a molecular biomarker to determine the sensitivity to Pa-PDT in immortalized human oral keratinocytes (IHOK) and OSCC cell lines. Methods: For this study, two immortalized oral keratinocytes (IHOK-p, IHOK-s) and 8 oral squamous cell carcinoma (OSCC) cell lines were used. After cells were treated with Pa-PDT, phototoxicity and the level of reactive oxygen species (ROS) were measured. Apoptosis was measured using annexin V/PI staining and western blotting. mRNA and proteins of apoptotic genes were investigated by RT-PCR, real-time PCR, and western blotting. Transfection was performed using RUNX3-small interfering RNA. Results: After Pa-PDT, cell viability was more than 50% reduced and ROS generated in IHOK and OSCC. In addition, apoptosis occurred in all cell lines. Among apoptosis-related genes, Bim expression was altered following Pa-PDT. Therefore, mRNA and protein expression of RUNX3, a gene upstream of Bim were examined by Pa-PDT. We found that RUNX3 was highly responsive to Pa-PDT. Furthermore, knockdown of RUNX3 expression reduced cytotoxicity by Pa-PDT. In addition, we found that the cytotoxicity by Pa-PDT was proportional to RUNX3 expression in OSCC cell lines. Conclusion: This is the first study to find a new target molecule that enhances Pa-PDT effects in IHOK and OSCC cell lines. These results should be further proven by animal studies to apply to clinical trials. Nevertheless, the development of a PDT-dependent biomarker could provide a novel approach to improve the effects of PDT in oral precancerous and cancerous lesions. Acknowledgments This study was supported by a grant of the Korean Health Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (No. A100490). Citation Format: Sook Moon, Jung Yoon Bae, Doo Young Lee, Gyeong Ju Park, Hyun Yoo, Hyo jin Ko, Yong Chul Kim, Jin Kim. RUNX3 is a biomarker for determining sensitivity to pheophorbide a-photodynamic therapy in human oral squamous cell carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3549. doi:10.1158/1538-7445.AM2013-3549

In Vitro Anti-tumor Effects of Photodynamic Therapy on Oral Squamous Cell Carcinoma: A Review

“…[56][57][58][59]62 Chlorophyll platform PSs, including chlorin e6, NPe6, chlorin p6, mTHPC, pheophorbide a, and 9-hydroxy pheophorbide a were applied in other studies . 29,31,38,39,41,43,49,54 One study used 15(1)-hydroxypurpurin-7-lactone ethyl methyl diester as a PS, which was isolated for the first time from an Araceae plant and referenced to Pha. 61 Natural PSs, like Spirulina platensis 64 and curcumin, 30 were among the used PSs.…”

“…Overall assessment showed slightly better results reported in the third generation and new PSs. Some studies used only one concentration, 33,[38][39][40]43,45,[47][48][49]51,55,56,58,59,66,67 while others evaluated the effect of different concentrations on their cell lines. 9,23,[29][30][31][32]34,36,37,41,42,44,46,50,53,54,57,[60][61][62][63][64][65]68 Most studies showed that the results were dependent on concentrations.…”

“…The most frequent light source was the laser, used in 19 studies (Table S1). 9,23,29,34,37,38,41,42,45,46,49,52,54,[58][59][60]62,64,66 Others included LEDs in 8, 32,40,50,51,57,63,65,69 a UV lamp 30,47,56 in three, and a Tungsten lamp 36,55 and a visible lamp, 30,48 each in two studies.…”

“…The most common range of wavelengths was 600-700 nm used in 26 studies. 9,23,29,[31][32][33][34][35]38,40,41,43,44,46,48,49,52,54,57,60,[63][64][65][66][67]69 Similarly, energy density had a wide range between 0.23 J/cm 2 and 122.58 J/cm 2 . Details are demonstrated in Table S1.…”

“…Viability/cytotoxicity and apoptosis were the most common outcomes examined in the included studies. Viability/cytotoxicity was mainly determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 9,23,29,32,[38][39][40]43,[45][46][47][50][51][52]54,58,61,64,66 although other tests including trypan blue exclusion assay, 29 CellTiter-Glo® luminescent cell viability assay, 31 WST-8 assay, 34 acridine orange-propidium iodide assay, cell counting Kit-8, 37,53 acridine orange/ethidium bromide assay, 32 live/dead cell assay, 46 modified alamarBlue assay, 50 and cytotoxicity lactate dehydrogenase release assay, 29,30,34 were also used.…”