TY - JOUR AB - The extracellular pH is lower inside solid tumors than in normal tissue. The acidic environment inhibits the cytotoxicity of lymphocytes in vitro and promotes tumor cell invasion. In the present study, both in vitro and in vivo experiments were conducted to investigate how NaHCO3 would affect the antitumor activities of cytokine‑induced killer (CIK) cells against hepatocellular carcinoma (HCC) cells. For the in vitro experiments, HepG2 cells were cultured at pH 6.5 and 7.4 in the presence of CIK cells or CIK cell‑conditioned medium (CMCIK). For the in vivo experiments, nude mice were xenografted with HepG2‑luc cells and divided into four groups: i) CIK cells injection plus NaHCO3 feeding; ii) CIK cells injection plus drinking water feeding; iii) normal saline injection plus NaHCO3 feeding; and iv) normal saline injection plus drinking water feeding. The results indicated that the viability and growth rate of HepG2 cells were remarkably suppressed when co‑cultured with CIK cells or CMCIK at pH 7.4 compared with those of HepG2 cells cultured under the same conditions but at pH 6.5. In the xenograft study, a marked synergistic antitumor effect of the combined therapy was observed. NaHCO3 feeding augmented the infiltration of cluster of differentiation 3‑positive T lymphocytes into the tumor mass. Taken together, these data strongly suggest that the antitumor activities of CIK cells against HepG2 cells were negatively affected by the acidic environment inside the tumors, and neutralizing the pH (for example, via NaHCO3 administration), could therefore reduce or eliminate this influence. In addition, it should be recommended that oncologists routinely prescribe soda water to their patients, particularly during CIK cell therapy. AD - Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China Department of Gastroenterology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China Department of Neurology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China Department of Infectious Diseases, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, Hubei 430000, P.R. China AU - Yuan,Ya ,Hong AU - Zhou,Chun ,Fang AU - Yuan,Jiang AU - Liu,Li AU - Guo,Xing ,Rong AU - Wang,Xiao ,Li AU - Ding,Yan AU - Wang,Xiao ,Nan AU - Li,Dong ,Sheng AU - Tu,Han ,Jun DA - 2016/11/01 DO - 10.3892/ol.2016.5112 EP - 3174 IS - 5 JO - Oncol Lett KW - NaHCO3 cytokine‑induced killer cells HepG2 extracellular pH acidic microenvironment PY - 2016 SN - 1792-1074 1792-1082 SP - 3167 ST - NaHCO3 enhances the antitumor activities of cytokine-induced killer cells against hepatocellular carcinoma HepG2 cells T2 - Oncology Letters TI - NaHCO3 enhances the antitumor activities of cytokine-induced killer cells against hepatocellular carcinoma HepG2 cells UR - https://doi.org/10.3892/ol.2016.5112 VL - 12 ER -