DNA is a highly unstable molecule. Endogenous souces of DNA damage, such as reactive oxygen species (ROS), can cause DNA damage and it has been estimated that 20000 lesions occur in a cell per day. BER is the major pathway for the repair of these lesions and therefore maintains genome stability, thus preventing the development of human diseases such as neurodegenerative diseases and cancer. Therefore, if BER cannot accomplish the repair, accumulation of DNA damage occurs, triggering different cellular responses, such as cell cycle delay and senescence. The ARF tumour suppressor protein, the gene of which is frequently mutated in many human cancers, plays an important role in the cellular stress response by orchestrating upregulation of p53 protein. Moreover, ARF expression is upregulated in senescent cells, suggesting that ARF induction might be triggerred in response to persistent DNA damage. Although ARF has been reported to be important in the regulation of proteins involved in the DNA damage response, its role is still controversial. Here, it has been shown that ARF gene transcription is induced by DNA strand breaks (SBs) and that ARF protein accumulates in response to persistent DNA damage generated by disabling BER. These data suggest that PARP1-dependent poly(ADP-ribose) synthesis at the sites of SBs initiates DNA damage signal transduction by reducing the cellular concentration of NAD⁺, thus inhibiting SIRT1 activity and consequently activating E2F1-dependent ARF transcription. These findings suggest a vital role for ARF in DNA damage signalling, and furthermore explain the critical requirement for ARF inactivation in cancer cells, which are frequently deficient in DNA repair and accumulate DNA damage.

Background: In the U.S., Hispanics have among the highest rates of overweight and obesity when compared to other racial/ethnic groups placing them at a greater risk for obesity-related disease. Identifying intervention strategies to reduce caloric intake and/or improve cardiometabolic health in Hispanics is critical to reducing morbidity and mortality among this large and growing population. Evidence exists to support diet-specific behavioral interventions, including beverage modifications, in reducing obesity-related health risks. However, the acceptability and feasibility of a beverage intervention in obese Hispanic adults has not been robustly evaluated. Methods: The objective of this pilot study is to assess the feasibility and acceptability of a randomized, controlled beverage intervention in 50 obese Hispanic adults ages 18-64 over 8-weeks. Eligible participants were obese (30-50.0 kg/m(2)), between the ages 18-64, self-identified as Hispanic, and were able to speak, read, and write in either English and/or Spanish. Study recruitment was completed August 2017. Upon the completion of baseline assessments, participants will be randomized to either Mediterranean lemonade, Green Tea, or flavored water control. After completing a 2-week washout period, participants will be asked to consume 32 oz. per day of study beverage for 6-weeks while avoiding all other sources of tea, lemonade, citrus, juice, and other sweetened beverages; water is permissible. Primary outcomes will be recruitment, retention, and acceptability of the intervention strategies. Our study will also evaluate participant-reported tolerance and as an exploratory aim, assess safety/toxicity-related to renal and/or liver function. Fasting blood samples will be collected at baseline and 8-weeks to assess the primary efficacy outcomes: total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL). Secondary outcomes include fasting glucose, hemoglobin A1c (HbA1c), and high-sensitivity C-reactive protein (hs-CRP). Discussion: This pilot study will provide important feasibility, safety, and early efficacy data necessary to design a larger, adequately-powered randomized controlled trial.

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