Inorganic polyphosphate enhances radio-sensitivity in a human non-small cell lung cancer cell line, H1299
- Tumour Biol. 2017 Jun;39(6):1010428317705033. doi: 10.1177/1010428317705033.
- 1. 1 Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
- 2. 2 Graduate School of Health Sciences, Hokkaido University, Sapporo, Japan.
- 3. 3 Sanda City Hospital, Sanda, Japan.
- 4. 4 School of Medicine, Hokkaido University, Sapporo, Japan.
- 5. 5 Hiroshima Heiwa Clinic High-Precision Radiotherapy Center, Hiroshima, Japan.
Inorganic polyphosphate is a linear polymer containing tens to hundreds of orthophosphate residues linked by high-energy phosphoanhydride bonds. Polyphosphate has been recognized as a potent anti-metastasis reagent. However, the molecular mechanism underlying polyphosphate action on Cancer cells is poorly understood. In this study, we investigated the involvement of polyphosphate in radio-sensitivity using a human Non-Small Cell Lung Cancer cell line, H1299. We found that polyphosphate treatment decreases cellular Adenosine triphosphate levels, suggesting a disruption of Energy Metabolism. We also found that the induction of DNA double-strand breaks was enhanced in polyphosphate-treated cells after X-ray irradiation and colony formation assay revealed that cell survival decreased compared with that of the control groups. These findings suggest that polyphosphate is a promising radio-sensitizer for Cancer cells. Therefore, we hypothesized that polyphosphate treatment disrupts Adenosine triphosphate-mediated energy transfer for cellular survival and DNA repair, thereby reducing the cellular capability to resist X-ray irradiation.