Cryptotanshinone enhances the effect of Arsenic trioxide in treating liver cancer cell by inducing apoptosis through downregulating phosphorylated- STAT3 in vitro and in vivo

Abstract

BackgroundArsenic trioxide (ATO) is approved for treating terminal-stage liver cancer in China. Cryptotanshinone (CT), a STAT3 inhibitor, has exhibited certain anti-tumor potency; however, the use of CT enhanced ATO for treating liver cancer has not been reported. Here we try to elucidate how CT could enhance the efficacy of ATO for treating liver cancer and its correlation to STAT3 in vitro and in vivo.MethodsCell viability of ATO combined with CT was assessed by 1MTT assay. Cell apoptosis induced by ATO combined with CT was detected by Annexin V/PI staining and apoptosis-related proteins were detected by western blotting. STAT3-related proteins were analysis by western blotting analysis and Immunofluorescence assays. Efficacy evaluation of ATO combined with CT on xenograft was carried in nude mice and related proteins were analysis by Immunohistochemistry assays.ResultsFirst we evaluated cell vitality, and our data indicated that the ATO combined with CT showed obvious growth inhibition of Bel-7404 cells compared to ATO or CT alone. Next we found that ATO combined with CT induced cell apoptosis in Bel-7404 cells and upregulated the activation of apoptosis-related proteins cleaved-caspase-3, cleaved-caspase-9, and cleaved-poly(ADP-ribose) polymerase in a time-dependent manner. Next, we found that ATO combined with CT not only inhibited the constitutive levels of phosphorylated-JAK2 and phosphorylated-STAT3Tyr705 but did so in a time-dependent manner. We also found that ATO combined with CT reversed the upregulated expression of phosphorylated-STAT3Tyr705 stimulated by interleukin-6 and downregulated STAT3 direct target genes and the anti-apoptotic proteins Bcl-2, XIAP, and survivin but obviously upregulated the promoting apoptosis proteins Bak,.In vivo studies showed that ATO combined with CT decreased tumor growth. Tumors from ATO combined with CT–treated mice showed decreased levels of phosphorylated-STAT3Tyr705 and the anti-apoptotic protein Bcl-2 but an increased level of pro-apoptotic protein Bax.ConclusionsOur study provides strong evidence that CT could enhance the efficacy of ATO in treating liver cancer both in vitro and in vivo. Downregulation of phosphorylated-STAT3 expression may play an important role in inducing apoptosis of Bel-7404 cells.

Cryptotanshinone suppresses cell proliferation and glucose metabolism via STAT3/SIRT3 signaling pathway in ovarian cancer cells

“…Cryptotanshinone (CT) is isolated from the plant Salvia miltiorrhiza Bunge and has been identified to block STAT3 phosphorylation and homodimerization . CT has been demonstrated to have anti‐tumor activities in various malignancies, including breast cancer,liver cancer,prostate cancer, and ovarian cancer . CT was found to induced apoptosis and cell cycle arrest in gastric cancer cells via reactive oxygen species (ROS)‐mediated MAPK and AKT signaling pathways .…”

“…[7][8][9] CT has been demonstrated to have anti-tumor activities in various malignancies, including breast cancer,liver cancer,prostate cancer, and ovarian cancer. [10][11][12][13] CT was found to induced apoptosis and cell cycle arrest in gastric cancer cells via reactive oxygen species (ROS)-mediated MAPK and AKT signaling pathways. 14,15 It has been reported that CT was a potent STAT3 inhibitor and inhibited STAT3 Tyr705 phosphorylation effectively in DU145 prostate cancer cells.…”

Crosstalk of mTOR/PKM2 and STAT3/c‐Myc signaling pathways regulate the energy metabolism and acidic microenvironment of gastric cancer

“…STAT3 is active in many hematological and solid tumors, including myeloma, lung cancer, prostate cancer, ovarian cancer, GC, and so on. This abnormal activation is associated with tumor cell proliferation, apoptosis, MDR, angiogenesis, invasion and metastasis, and other biological characteristics are closely related . Sustained activation of STAT3 maintains cell malignancy by upregulating multiple genes, whereas c‐Myc is one of the STAT3 downstream‐regulated target genes …”

Cryptotanshinone suppresses cell proliferation and induces apoptosis in renal cell carcinoma as an STAT3 inhibitor

“…In addition, the combination of CPT with some chemotherapeutic agents also achieved remarkable results. For instance, CPT synergized with Arsenic trioxide to induce apoptosis of liver cancer and breast cancer cells [17,18] ; synergized with imatinib to suppress the survival of K562 cells [19] ; enhanced the sensibility of ovarian cancer cells to cisplatin [13] ; potentiated the therapeutic effect of doxorubicin to gastric carcinoma [20] . Moreover, CPT was effective to drug resistant lung cancer and colon cancer cells [21,22] .…”