DCA was identified as a possible agent that could synergistically inhibit A549 cell survival
DCA was identified as a possible agent that could synergistically inhibit A549 cell survival. cells. strong class=”kwd-title” Keywords: Sodium dichloroacetic acid (DCA), SIRT2, warburg effect, PDHA1, drug synergy Introduction Sirtuins (SIRT1-7) are a class of enzymes with nicotinamide adenine dinucleotide (NAD)-dependent protein lysine deacylase function.1 Among these seven members, SIRT2 has been shown to regulate multiple cellular processes including cell motility, cell proliferation and survival, cell-cycle progression, apoptosis, lipid synthesis, fatty acid oxidation, glucogenesis and oxidative stress.2-5 Because of the wide range of its functions, interest in SIRT2 as a potential target leads to the development and utilization of various specific inhibitors.6-10 Among them, AGK211,12 and Sirtinol13,14 are two selective and potent inhibitors which have therapeutic value for cancer intervention. Sirtinol was identified as an inhibitor of silent information regulator (Sir2) family of proteins in a high throughput phenotypic screening of cells.8 Later researches revealed its anticancer potential in multiple cancer cells, including MCF-7 and H1299 cells.15 Moreover, Sirtinol enhanced chemo-sensitivity to camptothecin and cisplatin in PC3, DU145 and HeLa cells.14,16 AGK2 was originally reported to rescue alpha-synuclein-mediated toxicity in models of Parkinsons disease.9 Subsequent studies disclosed that AGK2 also achieved neuroprotection in cellular and invertebrate models of Huntingtons disease (HD).17 In addition to its neuroprotective effect, AGK2 was shown to have anti-cancer effects in cervical cancer cells12,18 and glioma cells.19 Within the past few decades, Cefprozil hydrate (Cefzil) drug combination therapy has been intensively studied in oncology and other complex disease areas, as this strategy has the potential to improve treatment response, minimize or delay development of resistance and reduce dose and toxicity.20 There is evidence revealing the link between SIRT2 expression and poor prognosis in non-small cell lung cancer,21 as well as its role in the response of the tumor to chemotherapy.22,23 On these bases, we believe that inhibiting SIRT2 pharmacologically by Sirtinol and AGK2 has the potential to enhance sensitivity of current small molecular drugs. In this study, we combined SIRT2 inhibitor Sirtinol, with a panel of small molecular anticancer brokers and we found that Dichloroacetate acid (DCA), a pyruvate dehydrogenase kinase inhibitor, could combine with Sirtinol/AGK2 to produce a synergistic therapeutic benefit. Further, we identified that this drug combination cooperates to activate PDHA1, shift the metabolism to OXPHOS, enhance ROS generation and activate AMPK signaling. These results indicate that this combination of DCA with Sirtinol and AGK2 may provide a promising therapeutic approach for NSCLC. Results Combination of Sirtinol/AGK2 with DCA leads to synergistic killing of non-small cell lung cancer cells To identify the small molecular anticancer brokers that would be more effective at killing cancer cells by combining with Sirtinol, A549 cells seeded in 96-well plates were treated with a panel of compounds (5-FU, cisplatin, Irinotecan, Paclitaxel, Erlotinib, Oxaliplatin, Etoposide, Gefitinib, 2DG, Cefprozil hydrate (Cefzil) DCA, Metformine) with Sirtinol for 72h and cell viability was determined by CCK-8 assay. The results show that Sirtinol could enhance therapeutic effects of several drugs to various extent, with DCA having the most dramatic combinational effect (Physique 1A). DCA is usually a generic drug with low price which has been used for human treatments for more than 30 years and has the ability to penetrate most tissues after oral administration. Therefore, we carried out further research focusing on DCA and SIRT2 inhibitor. The co-treatment of DCA with Sirtinol or Cefprozil hydrate (Cefzil) AGK2 effectively decreased survival by 80C90% consistently in both H1299 and A549 cell lines. However, in human embryonic lung fibroblast HFL-1 cells, the cell viability showed no further decrease in co-treatment group compared with single-treatment group, indicating that the combinational strategy was relatively safe for normal cells(Physique1B). To investigate whether inhibition following co-treatment of Sirtinol and DCA was synergistic or otherwise, cells were treated with increasing doses of Foxd1 Sirtinol (0-50M) or DCA (0-50mM) alone or in combination at a fixed ratio (1:1000) for 72?h and analyzed by CCK-8 assay. The dose-effect curve for each drug was decided and combination index (CI) values were calculated using Calcusyn software according to the Chou-Talalay method, whereas effect on cell viability was expressed as fraction of cells Cefprozil hydrate (Cefzil) affected.24,25 CI is a quantitative measure that allows.