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Processing of oxidatively induced clustered DNA lesions under a double strand break repair deficiency in human tumor cells

Final Report Summary - DSBR AND CLUSTERS (Processing of oxidatively induced clustered DNA lesions under a double strand break repair deficiency in human tumor cells)

1. Publishable summary (expected length: max. 500 words)
The overall goal of this proposal was to identify the association of the specific DSBR deficiencies with the processing of non-DSB oxidatively-induced clustered DNA lesions (OCDLs) primarily in human tumor cells, investigate the biochemical pathways involved and biological or clinical significance. Our hypothesis has been that double strand break repair (DSBR) proteins BRCA1 (HR) or DNA-PKcs (NHEJ) will be implicated also, directly or indirectly, in the processing of non-DSB oxidative single and clustered DNA lesions (OCDLs). The project consists primarily by three objectives (aims): Aim 1: Assessment of repair efficiency of single and clustered oxidatively-induced DNA lesions (SSBs, AP sites and oxidized bases, OCDLs) in a panel of DSBR deficient human tumor cell lines after a challenging ‘low’ dose of γ-rays. Aim 2: Investigation of the effects of DNA-PKcs/BRCA1 knockdown or inhibition of base excision repair (BER) and other DNA repair pathways. Aim 3: Correlation between non-DSB OCDL repair, apoptosis and chromosomal instability.

Overall Description of the work performed and main results out of this project
We have gained specific knowledge on the mechanisms human tumor cells with DSB repair deficiencies process non-DSB lesions induced by ionizing radiation and other types of stresses. We believe and based also on preliminary results, the key DSBR proteins BRCA1, DNA-PK will be implicated in the processing also of oxidative lesions indirectly. Their specific possible associations with base excision repair (BER) proteins like XRCC1 have been targeted. Increased apoptosis and high levels of chromosomal instability in the case different repair pathways are blocked by BRCA1 or DNA-PK deficiency or inhibition using siRNA strategies.
Impact: The above results and the successful completion of the project is expected to contribute significantly towards answering two of the most basic questions in current radiation and cancer biology regarding the processing of complex DNA lesions and their contribution to chromosomal instability if left unrepaired or misrepaired (cancer predisposition). In addition is expected to create knowledge with potential clinical use in radiation therapy for the enhancement of tumor cell killing especially in the case tumor cells carry a DSB repair deficiency like in breast, ovarian cancer etc.

The outcome of this research is expected to contribute significantly towards answering two of the most basic questions in current radiation and cancer biology: 1. which are the repair pathways involved in the processing of the highly toxic clustered DNA lesions, especially under a DSB repair deficiency and after exposure of the cell to radiation like in radiation therapy? No specific data has been provided from other laboratories internationally except Dr. Georgakilas and Dr. Chen both of them from USA 2. Can the DSB repair deficiencies for example observed in many tumors to lead to chromosomal instability through the accumulation of non-DSB lesions and cell death? The combination of a DNA repair deficiency and high oxidative stress is a common situation in many tumors. In addition, it has been shown that radiosensitive individuals have a higher predisposition to many cancers.

Dissemination activities Mean Journal Citation Reports Impact Factor; IF): >2012: 7,2
More dissemination activities of Dr, Georgakilas, exciting results and work related to this project can be found in and for this grant also in

All publications total 48 related to the project, completed or in press can be found in the attached extra document “Complete list of publications for all periods”.
Pubmed official link:

Most important publications the last 4 years of the project
1. Nikitaki Z, Nikolov V, Mavragani IV, Plante I, Emfietzoglou D, Iliakis G, Georgakilas AG. Non-DSB clustered DNA lesions. Does theory colocalize with the experiment? Radiation Physics and Chemistry. 2016;In press.
2. Nikitaki Z, Mavragani IV, Laskaratou DA, Mangelis A, Nikolov V, Emfietzoglou D, Terzoudi G, Iliakis G, Georgakilas AG. Measurement of complex DNA damage induction and repair in human cellular systems after exposure to ionizing radiations of varying LET. Free Radical Research. 2016;In press.
3. Nikitaki Z, Mavragani IV, Laskaratou DA, Gika V, Moskvin VP, Theofilatos K, Vougas K, Stewart RD, Georgakilas AG. Systemic mechanisms and effects of ionizing radiation: A new 'old' paradigm of how the bystanders and distant can become the players. Semin Cancer Biol. 2016;37-38:77-95.
4. Mavragani IV, Laskaratou DA, Frey B, Candeias SM, Gaipl US, Lumniczky K, Georgakilas AG. Key mechanisms involved in ionizing radiation-induced systemic effects. A current review. Toxicology Research. 2016;5:12-33.
5. Vinay DS, Ryan EP, Pawelec G, Talib WH, Stagg J, Elkord E, Lichtor T, Decker WK, Whelan RL, Kumara HM, Signori E, Honoki K, Georgakilas AG, Amin A, Helferich WG, Boosani CS, Guha G, Ciriolo MR, Chen S, Mohammed SI, Azmi AS, Keith WN, Bhakta D, Halicka D, Fujii H, Aquilano K, Ashraf SS, Nowsheen S, Yang X, Choi BK, Kwon BS. Immune evasion in cancer: Mechanistic basis and therapeutic strategies. Semin Cancer Biol. 2015.
6. Pavlopoulou A, Savva GD, Louka M, Bagos PG, Vorgias CE, Michalopoulos I, Georgakilas AG. Unraveling the mechanisms of extreme radioresistance in prokaryotes: Lessons from nature. Mutation Research/Reviews in Mutation Research. 2015;In press.
7. Pateras IS, Havaki S, Nikitopoulou X, Vougas K, Townsend PA, Panayiotidis MI, Georgakilas AG, Gorgoulis VG. The DNA damage response and immune signaling alliance: Is it good or bad? Nature decides when and where. Pharmacol Ther. 2015;154:36-56.
8. Nikitaki Z, Hellweg C, Georgakilas AG, Ravanat JL. Stress-induced DNA Damage biomarkers: Applications and limitations Front Chem. 2015;3:35.
9. Georgakilas AG, Pavlopoulou A, Louka M, Nikitaki Z, Vorgias CE, Bagos PG, Michalopoulos I. Emerging molecular networks common in ionizing radiation, immune and inflammatory responses by employing bioinformatics approaches. Cancer Lett. 2015;368:164-72.
10. Georgakilas AG. Role of the immune system and inflammation in ionizing radiation effects. Cancer Lett. 2015.
11. Georgakilas AG. Bystander and non-targeted effects: a unifying model from ionizing radiation to cancer. Cancer Lett. 2015;356:3-4.
12. Feitelson MA, Arzumanyan A, Kulathinal RJ, Blain SW, Holcombe RF, Mahajna J, Marino M, Martinez-Chantar ML, Nawroth R, Sanchez-Garcia I, Sharma D, Saxena NK, Singh N, Vlachostergios PJ, Guo S, Honoki K, Fujii H, Georgakilas AG, Amedei A, Niccolai E, Amin A, Ashraf SS, Boosani CS, Guha G, Ciriolo MR, Aquilano K, Chen S, Mohammed SI, Azmi AS, Bhakta D, Halicka D, Nowsheen S. Sustained proliferation in cancer: Mechanisms and novel therapeutic targets. Semin Cancer Biol. 2015.
13. Block KI, Gyllenhaal C, Lowe L, Amedei A, Amin ARMR, Amin A, Aquilano K, Arbiser J, Arreola A, Arzumanyan A, Ashraf SS, Azmi AS, Benencia F, Bhakta D, Bilsland A, Bishayee A, Blain SW, Block PB, Boosani CS, Carey TE, Carnero A, Carotenuto M, Casey SC, Chakrabarti M, Chaturvedi R, Chen GZ, Chen H, Chen S, Chen YC, Choi BK, Ciriolo MR, Coley HM, Collins AR, Connell M, Crawford S, Curran CS, Dabrosin C, Damia G, Dasgupta S, DeBerardinis RJ, Decker WK, Dhawan P, Diehl AME, Dong J-T, Dou QP, Drew JE, Elkord E, El-Rayes B, Feitelson MA, Felsher DW, Ferguson LR, Fimognari C, Firestone GL, Frezza C, Fujii H, Fuster MM, Generali D, Georgakilas AG, Gieseler F, Gilbertson M, Green MF, Grue B, Guha G, Halicka D, Helferich WG, Heneberg P, Hentosh P, Hirschey MD, Hofseth LJ, Holcombe RF, Honoki K, Hsu H-Y, Huang GS, Jensen LD, Jiang WG, Jones LW, Karpowicz PA, Keith WN, Kerkar SP, Khan GN, Khatami M, Ko YH, Kucuk O, Kulathinal RJ, Kumar NB, Kwon BS, Le A, Lea MA, Lee H-Y, Lichtor T, Lin L-T, Locasale JW, Lokeshwar BL, Longo VD, Lyssiotis CA, MacKenzie KL, Malhotra M, Marino M, Martinez-Chantar ML, Matheu A, Maxwell C, McDonnell E, Meeker AK, Mehrmohamadi M, Mehta K, Michelotti GA, Mohammad RM, Mohammed SI, Morre DJ, Muralidhar V, Muqbil I, Murphy MP, Nagaraju GP, Nahta R, Niccolai E, Nowsheen S, Panis C, Pantano F, Parslow VR, Pawelec G, Pedersen PL, Poore B, Poudyal D, Prakash S, Prince M, Raffaghello L, Rathmell JC, Rathmell WK, Ray SK, Reichrath J, Rezazadeh S, Ribatti D, Ricciardiello L, Robey RB, Rodier F, Rupasinghe HPV, Russo GL, Ryan EP, Samadi AK, Sanchez-Garcia I, Sanders AJ, Santini D, Sarkar M, Sasada T, Saxena NK, Shackelford RE, Shantha Kumara HMC, Sharma D, Shin DM, Sidransky D, Siegelin MD, Signori E, Singh N, Sivanand S, Sliva D, Smythe C, Spagnuolo C, Stafforini DM, Stagg J, Subbarayan PR, Sundin T, Talib WH, Thompson SK, Tran PT, Ungefroren H, Vander Heiden MG, Venkateswaran V, Vinay DS, Vlachostergios PJ, Wang Z, Wellen KE, Whelan RL, Yang ES, Yang H, Yang X, Yaswen P, Yedjou C, Yin X, Zhu J, Zollo M. Designing a broad-spectrum integrative approach for cancer prevention and treatment. Seminars in Cancer Biology. 2015;35, Supplement:S276-S304.
14. Georgakilas AG, Tsantoulis P, Kotsinas A, Michalopoulos I, Townsend P, Gorgoulis VG. Are common fragile sites merely structural domains or highly organized "functional" units susceptible to oncogenic stress? Cellular and molecular life sciences : CMLS. 2014;71:4519-44.
15. Georgakilas AG, Redon CE, Ferguson NF, Kryston TB, Parekh P, Dickey JS, Nakamura AJ, Mitchell JB, Bonner WM, Martin OA. Systemic DNA damage accumulation under in vivo tumor growth can be inhibited by the antioxidant Tempol. Cancer Lett. 2014;353:248-57.
16. Yang G, Nowsheen S, Aziz K, Georgakilas AG. Toxicity and adverse effects of Tamoxifen and other anti-estrogen drugs. Pharmacol Ther. 2013;139:392-404.
17. Georgakilas AG, O'Neill P, Stewart RD. Induction and repair of clustered DNA Lesions: What do we know so far? Radiat Res. 2013;180:100–9.
18. Chen Z, Pan X, Georgakilas AG, Chen P, Hu H, Yang Y, Tian S, Xia L, Zhang J, Cai X, Ge J, Yu K, Zhuang J. Tetramethylpyrazine (TMP) protects cerebral neurocytes and inhibits glioma by down regulating chemokine receptor CXCR4 expression. Cancer Lett. 2013;336:281-9.