Category Archives: cardio-protective

Schisandrin

Cancer: Leukemia, breast

Action: Anti-metastatic, cardio-protective, MDR, CYP3A, cell-cycle arrest

Leukemia

Schisandrin B (Sch B) has previously been demonstrated to be a novel P-glycoprotein (P-gp) inhibitor. Recent investigation revealed that Sch B was also an effective inhibitor of the multi-drug resistance-associated protein 1 (MRP1). Sch B's ability to reverse MRP1-mediated drug resistance was tested using HL60/ADR and HL60/MRP human promyelocytic leukemia cell lines, with the overexpression of MRP1 but not P-gp. At the equimolar concentration, Sch B demonstrated significantly stronger potency than the drug probenecid, a MRP1 inhibitor (Sun, Xu, Lu, Pan & Hu, 2007).

Up-regulates CYP3A

The ability of Schisandrin B (Sch B) to modulate cytochrome P450 3A activity (CYP3A) and alter the pharmacokinetic profiles of CYP3A substrate (midazolam) was investigated in vivo in treated rats. Rats were routinely administered with physiological saline (negative control group), ketoconazole (75mg/kg, positive control group), or varying doses of Sch B (experimental groups) for 3 consecutive days. Thereafter, changes in hepatic microsomal CYP3A activity and the pharmacokinetic profiles of midazolam and 1′-hydroxy midazolam in plasma were studied to evaluate CYP3A activity.

The results indicated that Sch B had a significant dose-dependent effect on inhibition of rat hepatic microsomal CYP3A activity. These results suggest that a 3-day treatment of Sch B could increase concentration and oral bioavailability of drugs metabolized by CYP3A (Li, Xin, Yu, & Wu, 2013).

Attenuates Metastasis

NADPH oxidase 4 (NOX4) is a potential target for intervention of cancer metastasis, as reactive oxygen species (ROS) generated by this enzyme plays important roles in TGF-β signaling, an important inducer of cancer metastasis. Zhang, Liu & Hu (2013) show that TGF-β induces ROS production in breast cancer 4T1 cells and enhances cell migration; that the effect of TGF- β depends on NOX4 expression; and that knockdown of NOX4 via RNAi significantly decreases the migration ability of 4T1 cells in the presence or absence of TGF-β and significantly attenuates distant metastasis of 4T1 cells to lung and bone.

Sch B significantly suppresses the lung and bone metastasis of 4T1 cells via inhibiting EMT, suggesting its potential application in targeting the process of cancer metastasis. Sch B significantly suppressed the spontaneous lung and bone metastasis of 4T1 cells inoculated s.c. without significant effect on primary tumor growth and significantly extended the survival time of the mice. Sch B did not inhibit lung metastasis of 4T1 cells that were injected via tail vein. Delayed start of treatment with Sch B in mice with pre-existing tumors did not reduce lung metastasis. These results suggested that Sch B acted at the step of local invasion (Liu et al., 2012).

Cardiotoxicity Protective/ Attenuates Metastasis

Sch B is capable of protecting Dox-induced chronic cardiotoxicity and enhancing its anti-cancer activity. To the best of our knowledge, Sch B is the only molecule ever proved to function as a cardio-protective agent as well as a chemotherapeutic sensitizer, which is potentially applicable for cancer treatment.

Pre-treatment with Sch B significantly attenuated Dox-induced loss of cardiac function and damage of cardiomyocytic structure. Sch B substantially enhanced Dox cytotoxicities toward S180 in vitro and in vivo in mice, and increased Dox cytotoxcity against 4T1 in vitro. Although we did not observe this enhancement against the implanted 4T1 primary tumor, the spontaneous metastasis to lung was significantly reduced in combined treatment group compared to Dox alone group (Xu et al., 2011).

Cell-cycle Arrest/Breast Cancer

Schizandrin inhibits cell proliferation through the induction of cell-cycle arrest with modulating cell-cycle-related proteins in human breast cancer cells. Schizandrin exhibited growth-inhibitory activities in cultured human breast cancer cells, and the effect was the more profound in estrogen receptor (ER)-positive T47D cells than in ER-negative MDA-MB-231 cells. When treated with the compound in T47D cells, schizandrin induced the accumulation of a cell population in the G0/G1 phase, which was further demonstrated by the induction of CDK inhibitors p21 and p27 and the inhibition of the expression of cell-cycle checkpoint proteins including cyclin D1, cyclin A, CDK2 and CDK4 (Kim et al., 2010).

References

Kim SJ, Min HY, Lee EJ, et al. (2010). Growth inhibition and cell-cycle arrest in the G0/G1 by schizandrin, a dibenzocyclooctadiene lignan isolated from Schisandra chinensis, on T47D human breast cancer cells. Phytother Res, 24(2):193-7. doi: 10.1002/ptr.2907.


Li WL, Xin HW, Yu AR, Wu XC. (2013). In vivo effect of Schisandrin B on cytochrome P450 enzyme activity. Phytomedicine, 20(8), 760-765


Liu Z, Zhang B, Liu K, Ding Z, Hu X. (2012). Schisandrin B attenuates cancer invasion and metastasis via inhibiting epithelial-mesenchymal transition. PLoS One, 7(7):e40480. doi: 10.1371/journal.pone.0040480.


Sun M, Xu X, Lu Q, Pan Q, Hu X. (2007). Schisandrin B: A dual inhibitor of P-glycoprotein and Multi-drug resistance-associated protein 1. Cancer Letters, 246(1-2), 300-307.


Xu Y, Liu Z, Sun J, et al. (2011). Schisandrin B prevents doxorubicin-induced chronic cardiotoxicity and enhances its anti-cancer activity in vivo. PLoS One, 6(12):e28335. doi: 10.1371/journal.pone.0028335.


Zhang B, Liu Z, Hu X. (2013). Inhibiting cancer metastasis via targeting NAPDH oxidase 4. Biochem Pharmacol, 86(2):253-66. doi: 10.1016/j.bcp.2013.05.011.

Baicalin & Baicalein

Cancer:
Myeloma, liver, colorectal., breast, prostate, oral., hepatoma, ovarian

Action: Anti-cancer, cardiovascular disease, cytostatic, cardio-protective against Doxorubicin, anti-inflammatory, angiogenesis

Baicalin and baicalein are naturally occurring flavonoids that are found in the roots and leaves of some Chinese medicinal plants (including Scutellaria radix, Scutellaria rivularis (Benth.); Scutellaria baicalensis (Georgi) and Scutellaria lateriflora (L.)) are thought to have anti-oxidant activity and possible anti-angiogenic, anti-cancer, anxiolytic, anti-inflammatory and neuroprotective activities. In particular, Scutellaria baicalensis is one of the most popular and multi-purpose herbs used in China traditionally for treatment of inflammation, hypertension, cardiovascular diseases, and bacterial and viral infections (Ye et al., 2002; Zhang et al., 2011a).

Anti-cancer

Accumulating evidence demonstrates that Scutellaria also possesses potent anti-cancer activities. The bioactive components of Scutellaria have been confirmed to be flavones, wogonin, baicalein and baicalin. These phytochemicals are not only cytostatic but also cytotoxic to various human tumor cell lines in vitro and inhibit tumor growth in vivo. Most importantly, they show almost no or minor toxicity to normal epithelial and normal peripheral blood and myeloid cells. The anti-tumor functions of these flavones are largely due to their abilities to scavenge oxidative radicals, to attenuate NF-kappaB activity, to inhibit several genes important for regulation of the cell-cycle, to suppress COX-2 gene expression and to prevent viral infections (Li, 2008).

Multiple Myeloma

In the search for a more effective adjuvant therapy to treat multiple myeloma (MM), Ma et al. (2005) investigated the effects of the traditional Chinese herbal medicines Huang-Lian-Jie-Du-Tang (HLJDT), Gui-Zhi-Fu-Ling-Wan (GZFLW), and Huang-Lian-Tang (HLT) on the proliferation and apoptosis of myeloma cells. HLJDT inhibited the proliferation of myeloma cell lines and the survival of primary myeloma cells, especially MPC-1- immature myeloma cells, and induced apoptosis in myeloma cell lines via a mitochondria-mediated pathway by reducing mitochondrial membrane potential and activating caspase-9 and caspase-3.

Further experiments confirmed that Scutellaria radix was responsible for the suppressive effect of HLJDT on myeloma cell proliferation, and the baicalein in Scutellaria radix showed strong growth inhibition and induction of apoptosis in comparison with baicalin or wogonin. Baicalein as well as baicalin suppressed the survival in vitro of MPC-1- immature myeloma cells rather than MPC-1+ myeloma cells from myeloma patients.

Baicalein inhibited the phosphorylation of IkB-alpha, which was followed by decreased expression of the IL-6 and XIAP genes and activation of caspase-9 and caspase-3. Therefore, HLJDT and Scutellaria radix have an anti-proliferative effect on myeloma cells, especially MPC-1- immature myeloma cells, and baicalein may be responsible for the suppressive effect of Scutellaria radix by blocking IkB-alpha degradation (Ma, 2005).

Hepatoma

The effects of the flavonoids from Scutellaria baicalensis Georgi (baicalein, baicalin and wogonin) in cultured human hepatoma cells (Hep G2, Hep 3B and SK-Hep1) were compared by MTT assay and flow cytometry. All three flavonoids dose-dependently decreased the cell viabilities accompanying the collapse of mitochondrial membrane potential and the depletion of glutathione content. However, the influence of baicalein, baicalin or wogonin on cell-cycle progression was different.

All three flavonoids resulted in prominent increase of G2/M population in Hep G2 cells, whereas an accumulation of sub G1 (hypoploid) peak in Hep 3B cells was observed. In SK-Hep1 cells, baicalein and baicalin resulted in a dramatic boost in hypoploid peak, but wogonin mainly in G1 phase accumulation. These data, together with the previous findings in other hepatoma cell lines, suggest that baicalein, baicalin and wogonin might be effective candidates for inducing apoptosis or inhibiting proliferation in various human hepatoma cell lines (Chang, 2002).

Long dan xie gan tang (pinyin) is one of the most commonly used herbal formulas by patients with chronic liver disease in China. Accumulated anecdotal evidence suggests that Long dan tang may have beneficial effects in patients with hepatocellular carcinoma. Long dan tang is comprised of five herbs: Gentiana root, Scutellaria root, Gardenia fruit, Alisma rhizome, and Bupleurum root. The cytotoxic effects of compounds from the five major ingredients isolated from the above plants, i.e. gentiopicroside, baicalein, geniposide, alisol B acetate and saikosaponin-d, were investigated, respectively, on human hepatoma Hep3B cells..

Interestingly, baicalein by itself induced an increase in H(2)O(2) generation and the subsequent NF-kappaB activation; furthermore, it effectively inhibited the transforming growth factor-beta(1) (TGF-beta(1))-induced caspase-3 activation and cell apoptosis. Results suggest that alisol B acetate and saikosaponin-d induced cell apoptosis through the caspase-3-dependent and -independent pathways, respectively. Instead of inducing apoptosis, baicalein inhibits TGF-beta(1)-induced apoptosis via increase in cellular H(2)O(2) formation and NF-kappaB activation in human hepatoma Hep3B cells (Chou, Pan, Teng & Guh, 2003).

Ovarian Cancer

Ovarian cancer is one of the primary causes of death for women all through the Western world. Two kinds of ovarian cancer (OVCAR-3 and CP-70) cell lines and a normal ovarian cell line (IOSE-364) were selected to be investigated in the inhibitory effect of baicalin and baicalein on cancer cells. Largely, baicalin and baicalein inhibited ovarian cancer cell viability in both ovarian cancer cell lines with LD50 values in the range of 45-55 µM for baicalin and 25-40 µM for baicalein. On the other hand, both compounds had fewer inhibitory effects on normal ovarian cells viability with LD50 values of 177 µM for baicalin and 68 µM for baicalein.

Baicalin decreased expression of VEGF (20 µM), cMyc (80 µM), and NFkB (20 µM); baicalein decreased expression of VEGF (10 µM), HIF-1α (20 µM), cMyc (20 µM), and NFkB (40 µM). Therefore baicalein is more effective in inhibiting cancer cell viability and expression of VEGF, HIF-1α, cMyc, and NFκB in both ovarian cancer cell lines. It seems that baicalein inhibited cancer cell viability through the inhibition of cancer promoting genes expression including VEGF, HIF-1α, cMyc, and NFκB.

Overall, this study showed that baicalein and baicalin significantly inhibited the viability of ovarian cancer cells, while generally exerting less of an effect on normal cells. They have potential for chemoprevention and treatment of ovarian cancers (Chen, 2013).

Breast Cancer

Baicalin was found to be a potent inhibitor of mammary cell line MCF-7 and ductal breast epithelial tumor cell line T-47D proliferation, as well as having anti-proliferative effects on other cancer types such as the human head and neck cancer epithelial cell lines CAL-27 and FaDu. Overall, baicalin inhibited the proliferation of human breast cancer cells and CAL-27 and FaDu cells with effective potency (Franek, 2005).

Breast Cancer, Cell Invasion

The effect of Baicalein on cell viability of the human breast cancer MDA-MB-231 cell line was tested by MTT. 50, 100 µmol·L-1 of Baicalein inhibited significantly cell invasion(P0.01) and migration(P0.01) compared with control groups. The inhibitory rates were 50% and 77% in cell migration and 15% and 44% in cell invasion, respectively. 50 µmol·L-1 of Baicalein significantly inhibited the level of MMP 2 expression. 100 µmol·L-1 of Baicalein significantly inhibited the level of MMP 9 and uPA expressions.

Baicalein inhibits invasion and migration of MDA-MB-231 cells. The mechanisms may be involved in the direct inhibition of cell invasion and migration abilities, and the inhibition of MMP 2, MMP 9, and uPA expressions (Wang et al., 2010).

The proliferation of MDA-MB-231 cell line human breast adenocarcinoma was inhibited by baicalin in a dose-and time-dependent manner and the IC50 was 151 µmol/L. The apoptotic rate of the baicalin-treated MDA-MB-231 cells increased significantly at 48 hours. Flow cytometer analysis also revealed that most of the baicalin-treated MDA-MB-231 cells were arrested in the G2/M phase. Typically apoptotic characteristics such as condensed chromatin and apoptotic bodies were observed after being treated with baicalin for 48 hours.

The results of RT-PCR showed that the expression of bax was up-regulated; meanwhile, the expression of bcl-2 was down-regulated. Baicalin could inhibit the proliferation of MDA-MB-231 cells through apoptosis by regulating the expression of bcl-2, bax and intervening in the process of the cell-cycle (Zhu et al., 2008).

Oral Cancer

As an aryl hydrocarbon receptor (AhR) ligand, baicalein at high concentrations blocks AhR-mediated dioxin toxicity. Because AhR had been reported to play a role in regulating the cell-cycle, it is suspected that the anti-cancer effect of baicalein is associated with AhR. The molecular mechanism involved in the anti-cancer effect of baicalein in oral cancer cells HSC-3 has been investigated, including whether such an effect would be AhR-mediated. Results revealed that baicalein inhibited cell proliferation and increased AhR activity in a dose-dependent manner. Cell-cycle was arrested at the G1 phase and the expression of CDK4, cyclin D1, and phosphorylated retinoblastoma (pRb) was decreased.

When cells were pre-treated with LiCl, the inhibitor of GSK-3β, the decrease of cyclin D1 was blocked and the reduction of pRb was recovered. The data indicates that in HSC-3 the reduction of pRb is mediated by baicalein both through activation of AhR and facilitation of cyclin D1 degradation, which causes cell-cycle arrest at the G1 phase, and results in the inhibition of cell proliferation (Cheng, 2012).

Anti-inflammatory

Baicalin has also been examined for its effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. The results indicated that baicalin inhibited LPS-induced NO production in a concentration-dependent manner without a notable cytotoxic effect on these cells. The decrease in NO production was consistent with the inhibition by baicalin of LPS-induced iNOS gene expression (Chen, 2001)

Angiogenesis Modulation

The modulation of angiogenesis is one possible mechanism by which baicalin may act in the treatment of cardiovascular diseases. This may be elucidated by investigating the effects of baicalin on the expression of vascular endothelial growth factor (VEGF), a critical factor for angiogenesis. The effects of baicalin and an extract of S. baicalensis on VEGF expression were tested in several cell lines. Both agents induced VEGF expression in all cells without increasing expression of hypoxia-inducible factor-1alpha (HIF-1alpha).

Their ability to induce VEGF expression was suppressed once ERRalpha expression was knocked down by siRNA, or ERRalpha-binding sites were deleted in the VEGF promoter. It was also found that both agents stimulated cell migration and vessel sprout formation from the aorta. These results therefore implicate baicalin and S. baicalensis in angiogenesis by inducing VEGF expression through the activation of the ERRalpha pathway (Zhang, 2011b).

Colon Cancer

The compounds of baicalein and wogonin, derived from the Chinese herb Scutellaria baicalensis, were studied for their effect in suppressing the viability of HT-29 human colon cancer cells. Following treatment with baicalein or wogonin, several apoptotic events were observed, including DNA fragmentation, chromatin condensation and increased cell-cycle arrest at the G1 phase. Baicalein and wogonin decreased Bcl-2 expression, whereas the expression of Bax was increased in a dose-dependent manner when compared to the control.

The results indicated that baicalein induced apoptosis via Akt activation, in a p53-dependent manner, in HT-29 colon cancer cells. Baicalein may serve as a chemo-preventive, or therapeutic, agent for HT-29 colon cancer (Kim et al., 2012).

Cardio-protective

The cardiotoxicity of doxorubicin limits its clinical use in the treatment of a variety of malignancies. Previous studies suggest that doxorubicin-associated cardiotoxicity is mediated by reactive oxygen species (ROS)-induced apoptosis. Baicalein attenuated phosphorylation of JNK induced by doxorubicin. Co-treatment of cardiomyocytes with doxorubicin and JNK inhibitor SP600125 (10 µM; 24 hours) reduced JNK phosphorylation and enhanced cell survival., suggesting that the baicalein protection against doxorubicin cardiotoxicity was mediated by JNK activation. Baicalein adjunct treatment confers anti-apoptotic protection against doxorubicin-induced cardiotoxicity without compromising its anti-cancer efficacy (Chang et al., 2011).

Prostate Cancer

There are four compounds capable of inhibiting prostate cancer cell proliferation in Scutellaria baicalensis: baicalein, wogonin, neobaicalein, and skullcapflavone. Comparisons of the cellular effects induced by the entire extract versus the four-compound combination produced comparable cell-cycle changes, levels of growth inhibition, and global gene expression profiles (r(2) = 0.79). Individual compounds exhibited anti-androgenic activities with reduced expression of the androgen receptor and androgen-regulated genes. In vivo, baicalein (20 mg/kg/d p.o.) reduced the growth of prostate cancer xenografts in nude mice by 55% at 2 weeks compared with placebo and delayed the average time for tumors to achieve a volume of approximately 1,000 mm(3) from 16 to 47 days (P < 0.001).

Most of the anti-cancer activities of S. baicalensis can be recapitulated with four purified constituents that function in part through inhibition of the androgen receptor signaling pathway (Bonham et al., 2005)

Cancer: Acute lymphocytic leukemia, lymphoma and myeloma

Action: Cell-cycle arrest, induces apoptosis

Scutellaria baicalensis (S.B.) is a widely used Chinese herbal medicine. S.B inhibited the growth of acute lymphocytic leukemia (ALL), lymphoma and myeloma cell lines by inducing apoptosis and cell cycle arrest at clinically achievable concentrations. The anti-proliferative effectwas associated with mitochondrial damage, modulation of the Bcl family of genes, increased level of the CDK inhibitor p27KIP1 and decreased level of c-myc oncogene. HPLC analysis of S.B. showed it contains 21% baicalin and further studies confirmed it was the major anti-cancer component of S.B. Thus, Scutellaria baicalensis should be tested in clinical trials for these hematopoietic malignancies (Kumagai et al., 2007).

References

Bonham M, Posakony J, Coleman I, Montgomery B, Simon J, Nelson PS. (2005). Characterization of chemical constituents in Scutellaria baicalensis with antiandrogenic and growth-inhibitory activities toward prostate carcinoma. Clin Cancer Res, 11(10):3905-14.


Chang WH Chen CH Lu FJ. (2002). Different Effects of Baicalein, Baicalin and Wogonin on Mitochondrial Function, Glutathione Content and cell-cycle Progression in Human Hepatoma Cell Lines. Planta Med, 68(2):128-32. doi: 10.1055/s-2002-20246


Chang WT, Li J, Huang HH, et al. (2011). Baicalein protects against doxorubicin-induced cardiotoxicity by attenuation of mitochondrial oxidant injury .and JNK activation. J Cell Biochem. doi: 10.1002/jcb.23201.


Chen J, Li Z, Chen AY, Ye X, et al. (2013). Inhibitory effect of baicalin and baicalein on ovarian cancer cells. Int J Mol Sci, 14(3):6012-25. doi: 10.3390/ijms14036012.


Chen YC, Shen SC, Chen LG, Lee TJ, Yang LL. (2001). Wogonin, baicalin, and baicalein inhibition of inducible nitric oxide synthase and cyclooxygenase-2 gene expressions induced by nitric oxide synthase inhibitors and lipopolysaccharide. Biochem Pharmacol,61(11):1417-27. doi:10.1016/S0006-2952(01)00594-9


Cheng YH, Li LA, Lin P, et al. (2012). Baicalein induces G1 arrest in oral cancer cells by enhancing the degradation of cyclin D1 and activating AhR to decrease Rb phosphorylation. Toxicol Appl Pharmacol, 263(3):360-7. doi: 10.1016/j.taap.2012.07.010.


Chou CC, Pan SL, Teng CM, & Guh JH. (2003). Pharmacological evaluation of several major ingredients of Chinese herbal medicines in human hepatoma Hep3B cells. European Journal of Pharmaceutical Sciences, 19(5), 403-12.


Franek KJ, Zhou Z, Zhang WD, Chen WY. (2005). In vitro studies of baicalin alone or in combination with Salvia miltiorrhiza extract as a potential anti-cancer agent. Int J Oncol, 26(1):217-24.


Kim SJ, Kim HJ, Kim HR, et al. (2012). Anti-tumor actions of baicalein and wogonin in HT-29 human colorectal cancer cells. Molecular Medicine Reports, 6(6):1443-1449. doi: 10.3892/mmr.2012.1085.


Li-Weber M. (2009). New therapeutic aspects of flavones: The anti-cancer properties of Scutellaria and its main active constituents Wogonin, Baicalein and Baicalin. Cancer Treat Rev, 35(1):57-68. doi: 10.1016/j.ctrv.2008.09.005.


Ma Z, Otsuyama K, Liu S, et al. (2005). Baicalein, a component of Scutellaria radix from Huang-Lian-Jie-Du-Tang (HLJDT), leads to suppression of proliferation and induction of apoptosis in human myeloma cells. Blood, 105(8):3312-8. doi:10.1182/blood-2004-10-3915.


Wang Xf, Zhou Qm, Su Sb. (2010). Experimental study on Baicalein inhibiting the invasion and migration of human breast cancer cells. Zhong Guo Yao Li Xue Tong Bao, 26(6): 745-750.


Zhang XW, Li WF, Li WW, et al. (2011a). Protective effects of the aqueous extract of Scutellaria baicalensis against acrolein-induced oxidative stress in cultured human umbilical vein endothelial cells. Pharm Biol, 49(3): 256–261. doi:10.3109/13880209.2010.501803.


Ye F, Xui L, Yi J, Zhang, W, Zhang DY. (2002). Anti-cancer activity of Scutellaria baicalensis and its potential mechanism. J Altern Complement Med, 8(5):567-72.


Zhang K, Lu J, Mori T, et al. (2011b). Baicalin increases VEGF expression and angiogenesis by activating the ERR{alpha}/PGC-1{alpha} pathway.[J]. Cardiovascular Research, 89(2):426-435.


Zhu Gq, Tang Lj, Wang L, Su Jj, et al. (2008). Study on Baicalin Induced Apoptosis of Human Breast Cancer Cell Line MDA-MB-231. An Hui Zhong Yi Xue Yuan Xue Bao, 27(2):20-23

Kumagai T, et al. (2007) Scutellaria baicalensis, a herbal medicine: Anti-proliferative and apoptotic activity against acute lymphocytic leukemia, lymphoma and myeloma cell lines. Leukemia Research 31 (2007) 523-530

Tanshinone II A & Tanshinone A (See also Cryptotanshinone)

Cancer:
Leukemia, prostate, breast, gastric, colorectal, nasopharyngeal carcinoma

Action: Chemo-sensitizer, cytostatic, cancer stem cells, anti-cancer, autophagic cell death, cell-cycle arrest

Anti-cancer

Tanshinone IIA and cryptotanshinone could induce CYP3A4 activity (Qiu et al., 2103).

Tanshinone II-A (Tan IIA) is the most abundant diterpene quinone isolated from Danshen (Salvia miltiorrhiza), which has been used in treating cardiovascular diseases for more than 2,000 years in China. Interest in its versatile protective effects in cardiovascular, metabolic, neurodegenerative diseases, and cancers has been growing over the last decade.

Tan IIA is a multi-target drug, whose molecular targets include transcription factors, scavenger receptors, ion channels, kinases, pro- and anti-apoptotic proteins, growth factors, inflammatory mediators, microRNA, and others. More recently, enhanced or synergistic effects can be observed when Tan IIA is used in combination therapy with cardio-protective and anti-cancer drugs (Xu & Liu, 2013).

Leukemia

The in vitro anti-proliferation and apoptosis-inducing effects of Tanshinone IIA on leukemia THP-1 cell lines and its mechanisms of action were investigated. MTT assay was used to detect the cell growth-inhibitory rate; cell apoptotic rate and the mitochondrial membrane potential (Deltapsim) were investigated by flow cytometry (FCM); apoptotic morphology was observed by Hoechst 33258 staining and DNA fragmentation analysis.

It was therefore concluded that Tanshinone IIA has significant growth inhibition effects on THP-1 cells by induction of apoptosis, and that Tanshinone IIA-induced apoptosis on THP-1 cells is mainly related to the disruption of Deltapsim and activation of caspase-3 as well as down-regulation of anti-apoptotic protein Bcl-2, survivin and up-regulation of pro-apoptotic protein Bax. The results indicate that Tanshinone IIA may serve as a potential anti-leukemia agent (Liu et al., 2009).

Prostate Cancer

Chiu et al. (2013) explored the mechanisms of cell death induced by Tan-IIA treatment in prostate cancer cells in vitro and in vivo. Results showed that Tan-IIA caused prostate cancer cell death in a dose-dependent manner, and cell-cycle arrest at G0/G1 phase was noted, in LNCaP cells. The G0/G1 phase arrest correlated with increased levels of CDK inhibitors (p16, p21 and p27) and decrease of the checkpoint proteins. Tan-IIA also induced ER stress in prostate cancer cells: activation and nuclear translocation of GADD153/CCAAT/enhancer-binding protein-homologous protein (CHOP) were identified, and increased expression of the downstream molecules GRP78/BiP, inositol-requiring protein-1α and GADD153/CHOP were evidenced. Blockage of GADD153/CHOP expression by siRNA reduced Tan-IIA-induced cell death in LNCaP cells.

Gastric Cancer

Tan IIA can reverse the malignant phenotype of SGC7901 gastric cancer cells, indicating that it may be a promising therapeutic agent.

Tan IIA (1, 5, 10 µg/ml) exerted powerful inhibitory effects on cell proliferation (P < 0.05, and P < 0.01), and this effect was time- and dose-dependent. FCM results showed that Tan IIA induced apoptosis of SGC7901 cells, reduced the number of cells in S phase and increased those in G0/G1 phase. Tan IIA also significantly increased the sensitivity of SGC7901 gastric cancer cells to ADR and Fu. Moreover, wound-healing and transwell assays showed that Tan IIA markedly decreased migratory and invasive abilities of SGC7901 cells (Xu et al., 2013).

Cell-cycle Arrest

MTT and SRB assays were applied to measure the effects of tanshinone A on cell viability. Cell-cycle distribution and apoptosis were assessed via flow cytometry using PI staining and the Annexin V/PI double staining method respectively. Changes to mitochondrial membrane potential was also detected by flow cytometry. The spectrophotometric method was utilized to detect changes of caspase-3 activity. Western blotting assay was used to evaluate the expression of Bcl-2, Bax and c-Myc proteins.

Results indicated that Tan-IIA displayed significant inhibitory effect on the growth of K562 cells in a dose- and time- dependent manner, and displayed only minimal damage to hepatic LO2 cells.

Tan-IIA could arrest K562 cells in the G0/G1 phase and induce apoptosis, decrease mitochondrial transmembrane potential, and the expressions of Bcl-2 and c-Myc proteins, increase the expression of Bax protein and activity of caspase-3. Accordingly, it was presumed that the induction of apoptosis may be through the endogenous pathway. Subsequently, tanshinone A could be a promising candidate in the development of a novel anti-tumor agent (Zhen et al., 2011).

Prostate Cancer, Chemo-sensitizer

Treatment with a combination of Chinese herbs and cytotoxic chemotherapies has shown a higher survival rate in clinical trials.

Tan-IIA displayed synergistic anti-tumor effects on human prostate cancer PC3 cells and LNCaP cells, when combined with cisplatin in vitro. Anti-proliferative effects were detected via MTT assay. Cell-cycle distribution and apoptosis were detected by flow cytometer. Protein expression was detected by Western blotting. The intracellular concentration of cisplatin was detected by high performance liquid chromatography (HPLC).

Results demonstrated that tanshinone II A significantly enhanced the anti-proliferative effects of cisplatin on human prostate cancer PC3 cells and LNCaP cells with an increase in the intracellular concentration of cisplatin. These effects were correlated with cell-cycle arrest at the S phase and induction of cell apoptosis. Apoptosis could potentially be achieved through the death receptor and mitochondrial pathways, decreased expression of Bcl-2.

Collectively, results indicated that the combination of tanshinone II A and cisplatin had a better treatment effect, in vitro, not only on androgen-dependent LNCaP cells but also on androgen-independent PC3 cells (Hou, Xu, Hu, & Xie, 2013).

Autophagic Cell Death, CSCs

Tan IIA significantly increased the expression of microtubule-associated protein light chain 3 (LC3) II as a hallmark of autophagy in Western blotting and immunofluorescence staining. Tan IIA augmented the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and attenuated the phosphorylation of mammalian target of rapamycin (mTOR) and p70 S6K in a dose-dependent manner.Tan IIA dramatically activated the extracellular signal regulated kinase (ERK) signaling pathway including Raf, ERK and p90 RSK in a dose-dependent and time-dependent manner. Consistently, ERK inhibitor PD184352 suppressed LC3-II activation induced by Tan IIA, whereas PD184352 and PD98059 did not affect poly (ADP-ribose) polymerase cleavage and sub-G1 accumulation induced by Tan IIA in KBM-5 leukemia cells.

Tan IIA induces autophagic cell death via activation of AMPK and ERK and inhibition of mTOR and p70 S6K in KBM-5 cells as a potent natural compound for leukemia treatment (Yun et al., 2013).

Cancer stem cells (CSCs) are maintained by inflammatory cytokines and signaling pathways. Tanshinone IIA (Tan-IIA) possesses anti-cancer and anti-inflammatory activities. The purpose of this study is to confirm the growth inhibition effect of Tan-IIA on human breast CSCs growth in vitro and in vivo and to explore the possible mechanism of its activity. After Tan-IIA treatment, cell proliferation and mammosphere formation of CSCs were decreased significantly; the expression levels of IL-6, STAT3, phospho-STAT3 (Tyr705), NF-κBp65 in nucleus and cyclin D1 proteins were decreased significantly; the tumor growth and mean tumor weight were reduced significantly.

Tan-IIA has the potential to target and kill CSCs, and can inhibit human breast CSCs growth both in vitro and in vivo through attenuation of IL-6/STAT3/NF-kB signaling pathways (Lin et al., 2013).

Colorectal Cancer

Tan II-A can effectively inhibit tumor growth and angiogenesis of human colorectal cancer via inhibiting the expression level of COX-2 and VEGF. Angiogenesis plays a significant role in colorectal cancer (CRC) and cyclooxygenase-2 (COX-2) appears to be involved with multiple aspects of CRC angiogenesis (Zhou et al., 2012). The results showed that Tan IIA inhibited the proliferation of inflammation-related colon cancer cells HCT116 and HT-29 by decreasing the production of inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), which are generated by macrophage RAW264.7 cell line.

Treatment with TanshinoneIIA prevented increased PU.1, a transcriptional activator of miR-155, and hence increased miR-155, whereas aspirin could not. These findings support that the interruption of signal conduction between activated macrophages and colon cancer cells could be considered as a new therapeutic strategy and miR-155 could be a potential target for the prevention of inflammation-related cancer (Tu et al., 2012).

Breast Cancer

The proliferation rate of T47D and MDA-MB-231 cells influenced by 1×10-6 mol·L-1 and 1×10-7 mol·L-1 Tanshinone IIA was analyzed by MTT assay. Estrogen receptor antagonist ICI182, 780 was employed as a tool. Level of ERα and ERβ mRNA in T47D cells was quantified by Real-time RT-PCR assay. Expression of ERα and ERβ protein was measured by flow cytometry. The proliferation rates of T47D cells treated with Tanshinone IIA decreased significantly. Such effects could be partly blocked by ICI182, 780.

Meanwhile, the proliferation rates of MDA-MB-231 cells treated with Tanshinone IIA decreased much more dramatically. Real-time RT-PCR and flow cytometry results showed that Tanshinone IIA could induce elevation of ERα and ERβ, especially ERα mRNA, and protein expression level in T47D cells. Tanshinone IIA shows inhibitory effects on proliferation of breast cancer cell lines (Zhao et al., 2010).

The role of cell adhesion molecules in the process of inflammation has been studied extensively, and these molecules are critical components of carcinogenesis and cancer metastasis. This study investigated the effect of tanshinone I on cancer growth, invasion and angiogenesis on human breast cancer cells MDA-MB-231, both in vitro and in vivo. Tanshinone I dose-dependently inhibited ICAM-1 and VCAM-1 expressions in human umbilical vein endothelial cells (HUVECs) that were stimulated with TNF-α for 6 h.

Additionally, reduction of tumor mass volume and decrease of metastasis incidents by tanshinone I were observed in vivo. In conclusion, this study provides a potential mechanism for the anti-cancer effect of tanshinone I on breast cancer cells, suggesting that tanshinone I may serve as an effective drug for the treatment of breast cancer (Nizamutdinova et al., 2008).

Nasopharyngeal Carcinoma

To investigate anti-cancer effect and potential mechanism of tanshinone II(A) (Tan II(A)) on human nasopharyngeal carcinoma cell line CNE cells, the anti-proliferative effect of Tan II(A) on CNE cells was evaluated by morphological examination, cell growth curves, colonial assay and MTT assay. Tan II(A) could inhibit CNE cell proliferation in dose- and time-dependent manner. After treatment with Tan II(A), intracellular Ca2+ concentration of CNE cells was increased, mitochondria membrane potential of the cells was decreased, relative mRNA level of Bad and MT-1A was up-regulated. Tan II(A) had an anti-cancer effect on CNE cells through apoptosis via a calcineurin-dependent pathway and MT-1A down-regulation, and may be the next generation of chemotherapy (Dai et al., 2011).

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