Anthocyanins From the Fruit of Vitis coignetiae Pulliat Potentiate the Cisplatin Activity by Inhibiting PI3K/Akt Signaling Pathways in Human Gastric Cancer Cells

Abstract

Background: Cisplatin (cis-diaminedichloroplatinum, CDDP) is a widely used chemotherapeutic agent for the treatment of many cancers. However, initial resistance to CDDP is a serious problem in treating these cancers. Vitis coignetiae Pulliat (Meoru in Korea) have shown anti-nuclear factor kappa B and anti-epidermal growth factor receptor activities in cancer cells.

Methods: In this study, in order to seeking an approach to increase the anti-cancer effects of CDDP with natural products. Here, we investigated anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) can enhance anti-cancer effects of cisplatin (CDDP) in stomach cancer cells. The cell viability of SNU-1 and SNU-16 cells after treated with AIMs and CDDP were analyzed by MTT assay. The expressions of Akt and X-linked inhibitor of apoptosis protein (XIAP) proteins were examined by western blot in AIMs- and CDDP-treated cells.

Results: We found that AIMs enhanced anticancer effects of CDDP, which activity was additive but not synergistic. AIMs suppressed Akt activity of the cancer cells activated by CDDP. AIMs also suppressed in XIAP an anti-apoptotic protein.

Conclusions: This study suggests that the anthocyanins isolated from fruits of Vitis coignetiae Pulliat enhanced anti-cancer effects of CDDP by inhibiting Akt activity activated by CDDP.

Keywords: Anthocyanins; Cisplatin; Stomach neoplasms.

Figure 1.

The inhibitory effects of anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) and/or cis-diaminedichloroplatinum (CDDP) on SNU-1, and SNU-16 human gastric cancer cells. Cell proliferation was assessed by MTT assay. (A, B) SNU-1 cells were treated with indicated concentrations of AIMs for 24 hours. (C–F) SNU-16 cells were treated with indicated concentrations of AIMs for 24 hours. The data are shown as means ± SD of three independent experiments. ^aP < 0.05 versus the untreated group. ^bP < 0.01 versus the untreated group. ^cP < 0.05 versus the CDDP-treated group.

Figure 2.

The effects of cis-diaminedichloroplatinum (CDDP) and/or anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) on Akt activity in SNU-16 cells. The expressions of phosphorylated Akt were assessed by Western blot analysis. (A) The cells were treated with CDDP (12 μg/mL) at indicated times. (B) Tumor necrosis factor (10 ng/mL) and CDDP were pretreated for 1 hour before AIMs treatment. Equal amounts of the cell lysate were separated by SDS-polyacrylamide gels and then transferred to nitrocellulose membranes and probed with the indicated antibodies and detected by an enhanced chemiluminescence detection system. Each result is a representative of at least two independent experiments. XIAP, X-linked inhibitor of apoptosis protein.

Figure 3.

Effects of anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) on cis-diaminedichloroplatinum (CDDP)-induced apoptosis by regulating p-Akt in SNU-16 cells. SNU-16 cells were seeded at the density of 5 × 10⁴ cells/mL. The cells were treated with CDDP (12 μg/mL) and/or AIMs (200 μM) for 24 hours. (A) Cell proliferation was assessed by MTT assay. The data are shown as mean ± SD of three independent experiments. ^aP < 0.05 versus the untreated group. ^bP < 0.05 versus the CDDP-treated group. (B) Equal amounts of cell lysate (30 μg) were resolved by SDS polyacrylamide gels and transferred onto nitrocellulose membranes. The membranes were probed with the indicated antibodies and detected by the enhanced chemiluminescence detection system. The results are from a representative experiment of at least three independent experiments that showed similar patterns. XIAP, X-linked inhibitor of apoptosis protein; PARP, poly adenosine diphosphate-ribose polymerase.

Figure 4.

Schematic representation of anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) enhances the cis-diaminedichloroplatinum (CDDP)-induced apoptosis in SNU-16 human gastric carcinoma cells. AIMS enhanced the CDDP-induced apoptosis by induction of Bax as well as suppressing X-linked inhibitor of apoptosis protein (XIAP) through the inhibition of Akt in p53 mutant SNU-16 cells. Also, AIMS Taken together, this study suggests that AIMs enhance anti-cancer effects of CDDP in p53 mutant SNU-16 human gastric cancer cells. PARP, Poly adenosine di-phosphate-ribose polymerase.