Abstract. Chinese herbs are potential sources of antitumor drugs with immunoregulatory activity and few adverse effects. In the present study, we investigated whether the Hypericum japonicum Thunb. (HJT) extract enhanced the efficacy of 5-fluorouracil (5-FU) treatment in murine liver tumor xenografts and reduced toxicity of chemotherapy in hepatoma H22-bearing mice. Tumor weight and inhibition rate, thymus and spleen indices, as well as white blood cell (WBC) count were calculated. The phagocytic function of macrophages was assessed by observing peritoneal macrophages phagocytized chicken red blood cells (RBC). Body weight and toxic reactions of the chemotherapeutic and life prolongation rate were investigated in the mice. Results demonstrated that the HJT extract significantly enhanced the tumor inhibition rate of 5-FU, improved the immune function, reduced the toxic effects and prolonged the survival time in the tumor-bearing mice. Taken together, these results indicated that the HJT extract has a synergistic tumor-inhibiting effect with 5-FU, is able to reduce the toxic side effects and is likely to be safe and efficacious for use in antitumor therapy.
IntrodutionLiver cancer is a malignant disease with a high incidence and mortality, and is often diagnosed at an advanced stage (1). Common therapies, such as surgical resection, percutaneous or transarterial interventions are of limited efficacy (2), as chemotherapy, one of the main measures for a comprehensive treatment, may induce adverse effects such as bone marrow suppression, gastrointestinal reactions and lowered immunological function.Several Chinese herbs have been identified as potential sources of antitumor drugs (3-5). The effect-enhancing and toxicity-reducing activity of Chinese herbs in radiotherapy and chemotherapy of tumors was previously confirmed (6,7). However, no studies focusing on the antitumor and toxicity-reducing effects of Hypericum japonicum Thunb. (HJT) have been reported thus far. Therefore, the present investigation was conducted to ascertain whether the HJT extract enhanced the efficacy of 5-fluorouracil (5-FU) treatment in murine liver tumor xenografts, and reduced toxicity of chemotherapy in tumor-bearing mice.
Materials and methodsReagents. RPMI-1640 medium, fetal bovine serum (FBS), penicillin G and streptomycin were obtained from Invitrogen Corp. (Carlsbad, CA, USA). 5-FU was obtained from the Shanghai Xudong Haipu Pharmaceutical Co., Ltd. (Shanghai, China). Murine H22 hepatoma cells were purchased from the Shanghai Institute of Cell Biology at the Chinese Academy of Sciences (Shanghai, China).
Animals. Institute of Cancer Research (ICR) mice(male/female, 50-50%; weight, 20±2 g) were purchased from the Experimental Animal Center, Zhengzhou University (Zhengzhou, China). The animals were kept in a standard laboratory, under a 12-h light/dark cycle, at room temperature (20±2˚C), in a humid (75±15%) and filtered laminar air flow-controlled room in the animal facility of the Experimental Animal Center of the Zhengzhou University...
