Radix Astragali and Tanshinone Help Carboplatin Inhibit B16 Tumor Cell Growth

Background: Excessive UV radiation causes increased melanoma incidence. Postoperation chemotherapy will destroy lymphocytes and compromise immune response. Immunodepression is also detected in patients with cancers. Previous studies suggested that polysaccharide-protein complexes manifested immunomodulatory and antitumor activities. Radix Astragali (RA) extract is a product of polysaccharide-protein complexes, which has been used in the treatment of a variety of diseases because of its low toxicity to the host. Tanshinone (TA) is a derivative of phenanthrenequinone isolated from Danshen, which is suggested to inhibit tumor growth by inducing apoptosis in tumor cells. Carboplatin (CA) is a commonly used chemotherapeutic drug in melanoma treatment. Therefore, we hypothesized that the combination of RA and TA will help CA better inhibit the B16 cell growth. Purpose: The study will test that the efficacy of growth inhibition of tumor cell produced by CA + RA + TA is better than CA + RA or CA + TA. Methods: The B16 tumor cells were injected to Swiss-Hauschka (ICR) mice subcutaneously. Twenty-four hours later, mice received CA intraperitoneally, CA + RA (RA were administered gastrically at the dosage of 10 g/kg body weight), CA + TA (TA were administered gastrically at the dosage of 0.5 g/kg body weight), or no treatment (model group). Tumor weight, volume, latency, incidence, the percentage of CD4(+) and CD8(+) in spleen, and natural killer (NK), and cytotoxic lymphocyte (CTL) activities were measured and compared among different groups. Results: Compared with mice treated with CA + RA, CA + TA, or CA alone, the mice treated with CA + RA + TA showed (1) significantly smaller tumor weight and tumor volume; (2) significantly longer tumor latency; (3) significantly lower tumor incidence; and (4) significantly increased percentage of CD4(+) and CD8(+) in spleen and increased activities of NK and CTL. Conclusion: Combination of RA and TA can help CA produce more effective inhibition on B16 cell growth.