Involvement of bax/bcl-2 in wogonin-induced apoptosis of human hepatoma cell line SMMC-7721

Evidence and possible mechanism of Scutellaria baicalensis and its bioactive compounds for hepatocellular carcinoma treatment

BACKGROUND

Traditional Chinese medicines have been reported to have outstanding effects in the treating of hepatocellular carcinoma. Scutellaria baicalensis (S. baicalensis) has demonstrated anti-tumor, anti-angiogenic, and anti-inflammatory properties. Baicalein, wogonin, and baicalin are the main pharmacologically bioactive compounds of S. baicalensis.

METHODS

Eight electronic databases were searched to select articles published from their inception to 30 May 2022. For selected articles, clinical and preclinical data was obtained on the use of S. baicalensis and its bioactive compounds in hepatocellular carcinoma therapy. Statistical analyses were performed using RevMan version 5.3 and Stata software. Quality assessment of the studies was performed using Cochrane and Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)'s risk of bias tools.

RESULTS

Seven clinical and 17 preclinical in vivo studies along with 31 in vitro studies were included in this research. Meta-analysis showed that a Chinese herbal medicine preparation, with S. baicalensis as the sovereign herb, combined with Transcatheter arterial chemoembolization (TACE) or primary treatment, could lead to a significantly improved tumor objective response rate (Risk ratio (RR) = 1.57, 95% confidence interval (CI): [1.30, 1.90], p < 0.00001). Scutellaria baicalensis-based extracts (standard mean difference (SMD) = -0.86, 95%CI: [-1.20, -0.53], p < 0.00001), baicalein (SMD = -4.80, 95%CI: [-6.66, - 2.95], p < 0.00001), baicalin (SMD = -2.28, 95%CI [-3.26, -1.30], p < 0.00001) and wogonin (SMD = -1.41, 95%CI [-2.26, -0.57], p < 0.00001) slowed tumor growth in vivo. These outcomes might be linked to the mechanism by which S. baicalensis promotes apoptosis, induces autophagy, and blocks the expression of vascular endothelial growth factor (p < 0.05).

CONCLUSION

Based on experimental and clinical evidence, we believe that S. baicalensis and its bioactive compounds have therapeutic potential and plausible mechanisms of action against hepatocellular carcinoma, in terms of efficacy and safety.

The Use of San-Huang-Xie-Xin-Tang Reduces the Mortality Rate among Breast Cancer Patients

Globally, breast cancer is the most common cause of cancer deaths. In Taiwan, it is the most prevalent cancer among females. Since San-Huang-Xie-Xin-Tang (SHXXT) exerts not only an anti-inflammatory but an immunomodulatory effect, it may act as a potent anti-tumor agent. Herein, the study aimed to explore the influence of SHXXT and its constituents on the mortality rate among breast cancer patients in Taiwan regarding the component effect and the dose-relationship effect. By using the Taiwan National Health Insurance (NHI) Research Database (NHIRD), the study analyzed 5387 breast cancer patients taking Chinese herbal medicine (CHM) and 5387 breast cancer patients not using CHM. CHM means SHXXT and its constituents in the study. The Kaplan-Meier method was utilized to determine the mortality probabilities among patients. Whether the CHM influences the mortality rate among patients was estimated by Cox proportional hazard regression analysis. The use of CHM could lower the cancer mortality rate by 59% in breast cancer patients. The protective effect was parallel to the cumulative days of CHM use and the annual average CHM dose. In addition, the mortality rate was lower in patients who used SHXXT compared to those who only used one of its constituents. SHXXT and its constituents were all promising therapeutic weapons against breast cancer.

Bcl-2 Modulation in p53 Signaling Pathway by Flavonoids: A Potential Strategy towards the Treatment of Cancer

Cancer is a major cause of death, affecting human life in both developed and developing countries. Numerous antitumor agents exist but their toxicity and low efficacy limits their utility. Furthermore, the complex pathophysiological mechanisms of cancer, serious side effects and poor prognosis restrict the administration of available cancer therapies. Thus, developing novel therapeutic agents are required towards a simultaneous targeting of major dysregulated signaling mediators in cancer etiology, while possessing lower side effects. In this line, the plant kingdom is introduced as a rich source of active phytochemicals. The secondary metabolites produced by plants could potentially regulate several dysregulated pathways in cancer. Among the secondary metabolites, flavonoids are hopeful phytochemicals with established biological activities and minimal side effects. Flavonoids inhibit B-cell lymphoma 2 (Bcl-2) via the p53 signaling pathway, which is a significant apoptotic target in many cancer types, hence suppressing a major dysregulated pathway in cancer. To date, there have been no studies reported which extensively highlight the role of flavonoids and especially the different classes of flavonoids in the modulation of Bcl-2 in the P53 signaling pathway. Herein, we discuss the modulation of Bcl-2 in the p53 signaling pathway by different classes of flavonoids and highlight different mechanisms through which this modulation can occur. This study will provide a rationale for the use of flavonoids against different cancers paving a new mechanistic-based approach to cancer therapy.

Fascinating Chemopreventive Story of Wogonin: A Chance to Hit on the Head in Cancer Treatment

Cancer, global havoc, is a group of debilitating diseases that strikes family as well as society. Cancer cases are drastically increasing these days. Despite many therapies and surgical procedures available, cancer is still difficult to control due to limited effective therapies or targeted therapies. Natural products can produce lesser side effects to the normal cells, which are the major demerit of chemotherapies and radiation. Wogonin, a natural product extracted from the plant, Scutellaria baicalensis has been widely studied and found with a high caliber to tackle most of the cancers via several mechanisms that include intrinsic as well as extrinsic apoptosis signaling pathways, carcinogenesis diminution, telomerase activity inhibition, metastasis inhibition in the inflammatory microenvironment, anti-angiogenesis, cell growth inhibition and arrest of the cell cycle, increased generation of H₂O₂ and accumulation of Ca²⁺ and also as an adjuvant along with anticancer drugs. This article discusses the role of wogonin in various cancers, its synergism with various drugs, and the mechanism by which wogonin controls tumor growth.

Effects of Platycodin D on apoptosis, migration, invasion and cell cycle arrest of gallbladder cancer cells

Platycodin D (PD) is a triterpenoid saponin that exists in the roots of Platycodonis. It exhibits evident growth inhibitory effects and potent cytotoxicity against multiple types of cancer. Gallbladder cancer (GBC) is the most common malignant disease of the biliary tract system. Patients with GBC usually have limited available treatment strategies and a poor prognosis. The present study investigated the antitumor effects of PD on human GBC cells in vitro and its underlying molecular mechanisms of action. The results indicated that PD, as assessed using MTT and colony forming assays, induced evident growth inhibition. Flow cytometry indicated that PD robustly induced apoptosis and blocked GBC cells at the G₂/M phase. Cell migration and invasion assays demonstrated that PD effectively inhibited the migratory and invasive abilities of GBC cell lines. Western blotting indicated that PD may initiate mitochondrial destruction in GBC cells through the JNK signaling pathway, thereby inducing apoptosis. The present results indicated that PD may exhibit antitumor effects by inducing apoptosis; inhibiting migration and invasion; and affecting the cell cycle in GBC cells. Therefore, PD has the potential to become a novel antitumor drug for GBC therapy.

Resveratrol inhibits viability and induces apoptosis in the small‑cell lung cancer H446 cell line via the PI3K/Akt/c‑Myc pathway

There have been no major breakthroughs in the treatment of small‑cell lung cancer (SCLC) in recent decades. It is thus essential to explore new or adjuvant treatment options for SCLC. Resveratrol (Res) is a natural antioxidant revealed to influence the entire process of cancer development. Accordingly, the present study used the SCLC cell line H446 to explore the antitumor mechanism of Res. Cells were treated with 40 µg/ml Res with or without pretreatment with the antioxidant N‑acetyl‑L‑cysteine (NAC). H446 cell viability and apoptosis were assessed with MTT and flow cytometry, and the expression of cytochrome c and the PI3K/Akt/c‑Myc pathway and the nuclear translocation of apoptosis inducing factor (AIF) were assessed by western blotting. In addition, the changes in ROS content and mitochondrial membrane potential were determined. The results revealed that Res inhibited H446 cell viability and induced apoptosis, increased cytochrome c expression, inhibited the expression of PI3K/Akt/c‑Myc signaling pathway components, and promoted the translocation of AIF from the cytoplasm to the nucleus in H446 cells. However, NAC pretreatment reversed these changes to various extents. The results of the present study indicated that Res may inhibit the viability and promote the apoptosis of human SCLC H446 cells through the PI3K/Akt/c‑Myc pathway and that oxidative stress and mitochondrial membrane potential depolarization may be involved in the aforementioned processes.

Wogonin improves functional neuroprotection for acute cerebral ischemia in rats by promoting angiogenesis via TGF-β1

Background

Previous studies showed that wogonin is a potential candidate for more effective treatment of neuronal and inflammatory disease and could offer neuroprotective activity in various models, but all these studies were in vitro. Our research aimed to investigate the neuroprotective effect of wogonin on focal cerebral ischemia in rats and uncover its potential mechanism.

Methods

A total of 80 male SD rats were randomly divided into a sham operation group (Sham group, 20 rats), a normal saline group (NS group, 20 rats), and a wogonin intervention group (W2W group, 20 rats), while the remaining 20 rats were kept as a substitute. The model of focal cerebral ischemia (MCAO) was established by thread embolization. The neurological deficits were evaluated by the modified neurological deficit scale (mNSS). The laser confocal technique was used to observe the diameter, density, and total area of microvessel. Lastly, the expression of transforming growth factor-β1 (TGF-β1) was detected by Western blot.

Results

The mNSS scores of the NS group and Wn2W group were 6.57±1.13 and 4.39±0.92 respectively, and the difference between NS group and Wn2W group was statistically significant (P<0.05); the vascular diameter of the Wn2W group, Sham group, and NS group were 2.93±0.19, 4.24±0.16, and 3.56±0.22 µm respectively, and the differences among these groups were statistically significant (F=102.142, P<0.01). Furthermore, the differences in the vascular density (F=290.49, P<0.01) and total microvessel area (F=163.08, P<0.01) among these groups were also statistically significant. The expression of TGF-β1 in ischemic brain tissue of the Sham group, NS group, and Wn2W group were 0.46±0.14, 0.62±0.18, and 0.94±0.21 respectively, and the differences among these groups were statistically significant (F=102.142, P<0.01).

Conclusions

Wogonin can markedly reduce nerve injury and improve nerve function in rats with cerebral ischemia, which may be related to the TGF-β1 pathway.

Resveratrol promotes the sensitivity of small-cell lung cancer H446 cells to cisplatin by regulating intrinsic apoptosis

The aim of the present study was to evaluate the effects of resveratrol on small-cell lung cancer (SCLC) cell proliferation and apoptosis. The results demonstrated that resveratrol concentration- and time-dependently reduced H446 cell viability. In addition, cells treated with resveratrol displayed higher apoptotic rates, in association with mitochondrial depolarization, cytochrome c release from the mitochondrial compartment to the cytoplasm, apoptosis-inducing factor translocation from the mitochondrial compartment to the nucleus, and altered protein levels of Bcl-2, Bcl-xL and Bax. Furthermore, resveratrol promoted H446 cell inhibition by cisplatin, as reflected by reduced viability and increased apoptosis. These findings suggest that resveratrol exerts antitumor effects on SCLC H446 cells and promotes H446 cell killing by cisplatin via modulation of intrinsic apoptosis.

Activation of endoplasmic reticulum stress and the extrinsic apoptotic pathway in human lung cancer cells by the new synthetic flavonoid, LZ-205

It has been shown that flavonoids have anti-tumor activity. In this study, LZ-205, a newly synthesized flavonoid, was found to be effective in inducing apoptosis in human lung cancer cells in vivo and in vitro. Mechanistically, LZ-205 triggers reactive oxygen species (ROS)-induced endoplasmic reticulum (ER) stress and unfolded protein response, which could be reversed by silencing CHOP, a mediator of the ER stress-associated apoptosis. In addition, LZ-205-induced apoptosis is accompanied by the activation of both the mitochondrial apoptotic and extrinsic pathways, followed by decreased mitochondrial membrane potential (ΔΨm) and the alteration of the expression of mitochondria-related pro- and anti-apoptotic proteins. LZ-205 exhibits a potential antitumor effect in BALB/c nude mice bearing H460 tumor with low systemic toxicity. In summary, both the ROS-mediated ER stress pathway and the exogenous apoptotic pathway are involved in LZ-205-induced apoptosis in vitro and in vivo. Our data show a therapeutic potential of LZ-205 for the treatment of lung cancer.

Therapy Effects of Wogonin on Ovarian Cancer Cells

Background

Wogonin is a plant monoflavonoid and has been reported to induce apoptosis of cancer cells and show inhibitory effect on cancer cell growth. However, the detailed and underlying molecular mechanisms are not elucidated. In this study, we investigated the molecular and biological effects of wogonin in human ovarian A2780 cancer cells.

Materials and Methods

We determined the effects of wogonin on the changes of cell cycling and apoptotic responses of cells. Western blot analysis was used to measure the effects of wogonin on protein expressions.

Results

Our results showed that treatment with wogonin inhibited the cancer cell proliferation, decreased the percentage of G0/G1 subpopulation, and reduced invasiveness of A2780 cells. Exposure to wogonin also resulted in downregulated protein levels of estrogen receptor alpha (ER-α), VEGF, Bcl-2, and Akt and increased expressions of Bax and p53. In addition, exposure to wogonin increased caspase-3 cleavage and induced apoptosis in A2780 cells. Our study further showed that MPP, a specific ER-α inhibitor, significantly enhanced antitumor effects of wogonin in A2780 cells.

Conclusion

Our results suggest a potential clinical impact of wogonin on management of ovarian cancer.

Molecular mechanisms of Bombyx batryticatus ethanol extract inducing gastric cancer SGC-7901 cells apoptosis

Bombyx batryticatus is a traditional Chinese medicine. To understand apoptotic effect of B. batryticatus ethanol extract (BBE), we investigated the role of BBE in inducing apoptosis of human gastric cancer cells SGC-7901. Cells treated with BBE and apoptosis was assessed by methyl thiazolyl tetrazolium (MTT) assay, morphological changes, DNA fragmentation and flow cytometry assays. The expression of Bcl-2, Bax and P21 were evaluated by western blot analysis and real time polymerase chain reaction. MTT assay showed that the cytotoxicity of BBE extract on SGC-7901 cells was correlated with treatment time and concentration. After treatment with 6 mg/mL of BBE the microscopy showed that, the majority of SGC-7901 cells were obviously reduced, distorted and grew slowly. Annexin-V/propidium iodide double-staining assay emerge the early apoptosis and the late apoptosis after treatment with different times by laser confocal fluorescence microscopy and flow cytometer. Cell cycle analysis of SGC 79 cells showed that BBE induced cell cycle arrest in the G1 and G2 phases. DNA fragmentation indicated the trend of BBE inducing apoptosis on SGC-7901 cells. The qRT-PCR and western blot analysis indicated that the mRNA and protein expressions of Bax and P21 were significantly up-regulated whereas that of Bc1-2 was down-regulated after treatment with BBE for 24 h. Our results revealed a correlation between gene regulation and BBE-induced apoptosis, which might indicate the potential of BBE in cancer therapy.

Iso-suillin from Suillus flavus Induces Apoptosis in Human Small Cell Lung Cancer H446 Cell Line

Background:

The suillin isoform iso-suillin is a natural substance isolated from a petroleum ether extract of the fruiting bodies of the mushroom Suillus flavus. Previous studies have found its inhibition effect on some cancer cells, and we aimed to study its effects on human small cell lung cancer H446 cell line.

Methods:

Cell viability was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Cellular morphological changes (apoptosis and necrosis) were evaluated using an electron microscope and Hoechst 33258 staining detected by the inverted microscope. Flow cytometry was used to detect cell apoptosis, cell cycle distribution, and mitochondrial membrane potential. Protein expression was determined by Western blotting analysis.

Results:

Here, we describe the ability of iso-suillin to inhibit the growth of H446 cells in time- and dose-dependent way. Iso-suillin had no obvious impact on normal human lymphocyte proliferation at low concentrations (9.09, 18.17, or 36.35 μmol/L) but promoted lymphocyte proliferation at a high concentration (72.70 μmol/L). After treatment of different concentrations of iso-suillin (6.82, 13.63, or 20.45 μmol/L), the apoptosis rate of H446 cells increased with increasing concentrations of iso-suillin (16.70%, 35.54%, and 49.20%, respectively, all P < 0.05 compared with the control), and the expression of related apoptotic proteins in the mitochondrial pathway including cytochrome c and caspase-9 were up-regulated compared with the control (all P < 0.05). On the contrary, Bcl-2/Bax ratio was down-regulated compared with the control. Besides, the expression of pro-apoptotic proteins in the death receptor apoptosis pathway, including Fas-associating protein with a novel death domain and caspase-8, and the expression of caspase-3, a downstream regulatory protein of apoptosis, were also increased compared with the control (all P < 0.05). Inhibitors of caspase-9 and caspase-8 reversed the apoptosis process in H446 cells to varying degrees.

Conclusions:

These results suggest that iso-suillin could induce H446 cell apoptosis through the mitochondrial pathway and the death-receptor pathway. Therefore, iso-suillin might have a potential application as a novel drug for lung cancer treatment.

FV-429 induces apoptosis and inhibits glycolysis by inhibiting Akt-mediated phosphorylation of hexokinase II in MDA-MB-231 cells

In this study, the anticancer effect of a newly synthesized flavonoid FV-429, against human breast cancer MDA-MB-231 cells, and the underlying mechanisms were investigated. FV-429 triggered the apoptosis and simultaneously inhibited the glycolysis of MDA-MB-231 cells. Both the HK II activity and its level in mitochondria were significantly down regulated by FV-429. Moreover, FV-429 weakened the interaction between HKII and VDAC, stimulated the detachment of HK II from the mitochondria, and resulted in the opening of the mitochondrial permeability transition pores. Thus FV-429 induced the mitochondrial-mediated apoptosis, showing increased Bax/Bcl-2 ratio, loss of mitochondrial membrane potential (MMP) and activation of caspase-3 and -9, cytochrome c (Cyt c) release, and apoptosis inducing factor (AIF) transposition. Further research revealed that the phosphorylation of mitochondrial HKII via Akt was responsible for the dissociation of HKII and the decreased HKII activity induced by FV-429. Taken together, FV-429 inhibited the phosphorylation of HKII, down-regulated its activity, and stimulated the release of HKII from the mitochondria, resulting the inhibited glycolysis and mitochondrial-mediated apoptosis. The studies provide a molecular basis for the development of flavonoid compounds as novel anticancer agents for breast cancer. © 2015 Wiley Periodicals, Inc.

Chinese medicines for prevention and treatment of human hepatocellular carcinoma: current progress on pharmacological actions and mechanisms

Hepatocellular carcinoma (HCC) is one of leading causes of death in the world. Although various treatments have been developed, the therapeutic side effects are far from desirable. Chinese medicines (CMs, including plants, animal parts and minerals) have drawn a great deal of attention in recent years for their potential in the treatment of HCC. Most studies have shown that CMs may be able to retard HCC progression with multiple actions, either alone or in combination with other conventional therapies to improve quality of life in HCC patients. Additionally, CMs are used for preventing HCC occurrence. The aim of this study is to review the potential prophylactic and curative effects of CMs on human HCC and the possible mechanisms that underlie these pharmacological actions. Publications were collected and reviewed from PubMed and China National Knowledge Infrastructure from 2000 to 2014. Keywords for literature searches include "Chinese medicine", "Chinese herb", "traditional Chinese Medicine", "hepatocellular carcinoma" and "liver cancer". CMs in forms of pure compounds, isolated fractions, and composite formulas are included. Combination therapies are also considered. Both in vitro and in vivo efficacies of CMs are being discussed and the translational potential to bedside is to be discussed with clinical cases, which show the actions of CMs on HCC may include tumor growth inhibition, antimetastatic activities, anti-inflammation, anti-liver cancer stem cells, reversal on multi-drug resistance and induction/reduction of oxidative stress. Multiple types of molecules are found to contribute in the above actions. The review paper indicated that CMs might have potential to both prevent HCC occurrence and retard HCC progression with several molecular targets involved.

Natural compounds and pharmaceuticals reprogram leukemia cell differentiation pathways

In addition to apoptosis resistance and cell proliferation capacities, the undifferentiated state also characterizes most cancer cells, especially leukemia cells. Cell differentiation is a multifaceted process that depends on complex regulatory networks that involve transcriptional, post-transcriptional and epigenetic regulation of gene expression. The time- and spatially-dependent expression of lineage-specific genes and genes that control cell growth and cell death is implicated in the process of maturation. The induction of cancer cell differentiation is considered an alternative approach to elicit cell death and proliferation arrest. Differentiation therapy has mainly been developed to treat acute myeloid leukemia, notably with all-trans retinoic acid (ATRA). Numerous molecules from diverse natural or synthetic origins are effective alone or in association with ATRA in both in vitro and in vivo experiments. During the last two decades, pharmaceuticals and natural compounds with various chemical structures, including alkaloids, flavonoids and polyphenols, were identified as potential differentiating agents of hematopoietic pathways and osteogenesis.

Cbl participates in shikonin-induced apoptosis by negatively regulating phosphoinositide 3-kinase/protein kinase B signaling

Shikonin, a naturally occurring naphthoquinone, exhibits anti-tumorigenic activity. However, its precise mechanisms of action have remained elusive. In the present study, the involvement in the action of shikonin of the ubiquitin ligases Cbl-b and c-Cbl, which are negative regulators of phosphoinositide 3-kinase (PI3K) activation, was investigated. Shikonin was observed to reduce cell viability and induce apoptosis and G2/M phase arrest in lung cancer cells. In addition, shikonin increased the protein levels of B-cell lymphoma 2 (Bcl-2)-associated X and p53 and reduced those of Bcl-2. Additionally, shikonin inhibited PI3k/Akt activity and upregulated Cbl protein expression. In addition, a specific inhibitor of PI3K, LY294002, was observed to have a synergistic effect on the proliferation inhibition and apoptotic induction of A549 cells with shikonin. In conclusion, the results of the present study suggested that Cbl proteins promote shikonin-induced apoptosis by negatively regulating PI3K/Akt signaling in lung cancer cells.

Cytotoxicity of dietary flavonoids on different human cancer types

Flavonoids are ubiquitous in nature. They are also in food, providing an essential link between diet and prevention of chronic diseases including cancer. Anticancer effects of these polyphenols depend on several factors: Their chemical structure and concentration, and also on the type of cancer. Malignant cells from different tissues reveal somewhat different sensitivity toward flavonoids and, therefore, the preferences of the most common dietary flavonoids to various human cancer types are analyzed in this review. While luteolin and kaempferol can be considered as promising candidate agents for treatment of gastric and ovarian cancers, respectively, apigenin, chrysin, and luteolin have good perspectives as potent antitumor agents for cervical cancer; cells from main sites of flavonoid metabolism (colon and liver) reveal rather large fluctuations in anticancer activity probably due to exposure to various metabolites with different activities. Anticancer effect of flavonoids toward blood cancer cells depend on their myeloid, lymphoid, or erythroid origin; cytotoxic effects of flavonoids on breast and prostate cancer cells are highly related to the expression of hormone receptors. Different flavonoids are often preferentially present in certain food items, and knowledge about the malignant tissue-specific anticancer effects of flavonoids could be purposely applied both in chemoprevention as well as in cancer treatment.

Pharmacokinetics, tissue distribution, excretion and plasma protein binding studies of wogonin in rats

Wogonin is a natural anticancer candidate. The purpose of this study was to explore the pharmacokinetic profiles, tissue distribution, excretion and plasma protein binding of wogonin in Sprague—Dawley rats. A rapid, sensitive, and specific LC-MS/MS method has been developed for the determination of wogonin in different rat biological samples. After i.v. dosing of wogonin at different levels (10, 20 and 40 mg/kg) the elimination half-life was approximately 14 min, the AUC_0-∞ increased in a dose disproportional manner from 112.13 mg/L·min for 10 mg/kg to 758.19 mg/L·min for 40 mg/kg, indicating a non linear pharmacokinetic profile. After i.g. dosing at 100 mg/kg, plasma levels of wogonin peaked at 28 min with a C_max value of 300 ng/mL and a very low oral bioavailability (1.10%). Following i.v. single dose (20 mg/kg), wogonin was detected in all examined tissues (including testis) with the highest levels in kidney and liver. Approximately 21% of the administered dose was excreted as unchanged drug (mainly via non-biliairy fecal route (16.33%). Equilibrium dialysis was used to evaluate plasma protein binding of wogonin at three concentrations (0.1, 0.5 and 2 µg/mL). Results indicated a very high protein binding degree (over 90%), reducing substantially the free fraction of the compound.

LW-214, a newly synthesized flavonoid, induces intrinsic apoptosis pathway by down-regulating Trx-1 in MCF-7 human breast cells

In this study, the anticancer effect of LW-214, a newly synthesized flavonoid, against MCF-7 human breast cancer cells and the underlying mechanisms were investigated. LW-214 triggered the mitochondrial apoptotic pathway by increasing Bax/Bcl-2 ratio, loss of mitochondrial membrane potential (ΔΨm) and caspase-9 activation, degradation of poly (ADP-ribose) polymerase (PARP), cytochrome c (Cyt c) release and apoptosis-inducing factor (AIF) transposition. Further research revealed that both the reactive oxygen species (ROS) generation and the apoptosis signal regulating kinase 1 (ASK1) activation by LW-214 were induced by down-regulating the thioredoxin-1 (Trx-1) expression. The ROS elevation and ASK1 activation induced a sustained phosphorylation of c-Jun N-terminal kinase (JNK), while SP600125, as known as JNK inhibitor, almost reversed LW-214-induced apoptosis in MCF-7 cells. Overexpression of Trx-1 in MCF-7 cells attenuated LW-214-mediated apoptosis as well as the JNK activation and reversed the expression of mitochondrial apoptosis-related protein. Accordingly, the in vivo study showed that LW-214 exhibited a potential antitumor effect in BALB/c species mice inoculated MCF-7 tumor with low systemic toxicity, and the mechanism was the same as in vitro study. Taken together, these findings indicated that LW-214 may down-regulated Trx-1 function, causing intracellular ROS generation and releasing the ASK1, and lead to JNK activation, which consequently induced the mitochondrial apoptosis in vitro and in vivo.

Synergistic inhibitory effect of wogonin and low-dose paclitaxel on gastric cancer cells and tumor xenografts

OBJECTIVE

To investigate the synergistic inhibitory effects of wogonin (WOG) and chemotherapeutic drugs on growth of gastric cancer cells and tumor xenografts.

METHODS

The IC50 values of WOG, cisplatin (CDDP) and paclitaxel (PTX) in four gastric cancer cell lines were determined by MTS assay. Hoechst staining and the median effect method of Chou-Talalay were used to assess the apoptosis of cells and the interaction of two drugs, respectively. BGC-823-derived xenografts in nude mice were established to investigate the effects of WOG combined with chemotherapeutic drugs in vivo.

RESULTS

WOG, CDDP and PTX inhibited the growth of BGC-823, MGC-803, MKN-45 and HGC-27 gastric cancer cells in a dose-dependent manner. WOG combined with CDDP or PTX synergistically inhibited the growth of all gastric cancer cell lines in vitro. In BGC-823, MGC-803, HGC-27 and MKN-45 cell lines, synergisms between WOG and PTX were shown when the fraction affected (Fa) values were <0.45, <0.90, <0.85 and <0.60. While WOG and CDDP had a synergistic inhibitory effect when the Fa values were >0, >0, >0.65 and >0.10. From the results of in vivo experiments using tumor xenografts, WOG and low-dose PTX showed better efficacy than either drug alone. The inhibitory percentages of tumor weight were 61.58%, 20.29%, and 22.28% for the combination, WOG-alone, and low-dose PTX-alone groups, respectively. Notably, WOG combined with CDDP displayed very high toxicity.

CONCLUSIONS

A synergistic inhibitory effect on growth was observed when WOG was combined with low-dose PTX in gastric cancer cells and tumor xenografts. These findings provide evidence for the design of a clinical trial to test the combination of WOG with low-dose PTX in human gastric cancer.

Wogonin has multiple anti-cancer effects by regulating c-Myc/SKP2/Fbw7α and HDAC1/HDAC2 pathways and inducing apoptosis in human lung adenocarcinoma cell line A549

Wogonin is a plant monoflavonoid which has been reported to inhibit cell growth and/or induce apoptosis in various tumors. The present study examined the apoptosis-inducing activity and underlying mechanism of action of wogonin in A549 cells. The results showed that wogonin was a potent inhibitor of the viability of A549 cells. Apoptotic protein changes detected after exposure to wogonin included decreased XIAP and Mcl-1 expression, increased cleaved-PARP expression and increased release of AIF and cytotchrome C. Western blot analysis showed that the activity of c-Myc/Skp2 and HDAC1/HDAC2 pathways, which play important roles in tumor progress, was decreased. Quantitative PCR identified increased levels of c-Myc mRNA and decreased levels of its protein. Protein levels of Fbw7α, GSK3β and Thr58-Myc, which are involved in c-Myc ubiquitin-dependent degradation, were also analyzed. After exposure to wogonin, Fbw7α and GSK3β expression decreased and Thr58-Myc expression increased. However, MG132 was unable to prevent c-Myc degradation. The present results suggest that wogonin has multiple anti-cancer effects associated with degradation of c-Myc, SKP2, HDAC1 and HDAC2. Its ability to induce apoptosis independently of Fbw7α suggests a possible use in drug-resistance cancer related to Fbw7 deficiency. Further studies are needed to determine which pathways are related to c-Myc and Fbw7α reversal and whether Thr58 phosphorylation of c-Myc is dependent on GSK3β.

Wogonin induced cytotoxicity in human hepatocellular carcinoma cells by activation of unfolded protein response and inactivation of AKT

AIM

To investigate the potential anticancer effects of the natural flavonoid wogonin on human hepatocellular carcinoma (HCC) cells and tumor xenografts and the contribution of the unfolded protein response (UPR) and AKT pathways to the cytotoxicity of wogonin.

METHODS

The HCC cell lines HepG2, SMMC-7721 and Hep3B were treated with wogonin. 3-(4 5-Dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide assays were used to evaluate the cell viability. Flow cytometry assays were used to identify the cell death types and measure the concentrations of intracellular H2 O2 and Ca(2+) . Western blotting assays were used to detect the protein expression levels of members in the UPR and AKT pathways. Relative quantitative real-time polymerase chain reaction assays were used to analysis the mRNA expression levels of chop and trb3. Furthermore, the male BALB/c nude mice with SMMC-7721 xenografts were treated with wogonin. The tumor volume, tumor weight and bodyweight were monitored during the tumorigenicity assays.

RESULTS

Wogonin significantly inhibited the viability of HCC cells by inducing apoptosis and necrosis. This cytotoxicity was at least partially attributed to the activation of the UPR pathway and consequent inactivation of AKT signaling, which resulted from the production of intracellular H2 O2 and causal release of endoplasmic reticulum Ca(2+) . Moreover, wogonin evidently repressed the growth of xenografts but slightly influenced the bodyweight of mice.

CONCLUSION

Wogonin is a prospect for improving the systemic chemotherapy strategy on HCC by concurrently rectifying the aberrant UPR and AKT signaling pathways, which are crucial to the biology of HCC.

Current understanding on antihepatocarcinoma effects of xiao chai hu tang and its constituents

Xiao Chai Hu Tang (XCHT), a compound formula originally recorded in an ancient Chinese medical book Shanghanlun, has been used to treat chronic liver diseases for a long period of time in China. Although extensive studies have been demonstrated the efficacy of this formula to treat chronic hepatitis, hepatic fibrosis, and hepatocarcinoma, how it works against these diseases still awaits full understanding. Here, we firstly present an overview arranging from the entire formula to mechanism studies of single herb in XCHT and their active components, from a new perspective of "separation study," and we tried our best to both detailedly and systematically organize the antihepatocarcinoma effects of it, hoping that the review will facilitate the strive on elucidating how XCHT elicits its antihepatocarcinoma role.

Vitamin C induces apoptosis in AGS cells by down-regulation of 14-3-3σ via a mitochondrial dependent pathway

Ascorbic acid (vitamin C) is an essential component of most living cells. Apart from antioxidant activity, it has been reported to inhibit cancer cell growth in vitro in human cancer cells. However, the cellular mechanism underlying anticancer activity has not been fully elucidated. In this study, vitamin C showed a cytotoxic effect on human gastric cancer cell line AGS (LD50 300μg/ml). Further, flow cytometry analysis showed that vitamin C increased the sub-G1 (apoptosis) population and apoptosis confirmed by fluorescein isothiocyanate-Annexin V double staining in AGS cells. Moreover, specific immuno-blotting revealed the expression of the phosphorylated form of Bad (S136), 14-3-3σ, pro-caspases-3, -6, -8, and-9 protein levels were significantly decreased and Bax/Bcl-xL ratio was increased in a dose-dependent manner. Also, wound healing assay results showed that vitamin C inhibited AGS cell proliferation. These findings suggest that vitamin C induces apoptosis and might be a potential therapeutic agent for gastric cancer.

Wogonin induces apoptosis by activation of ERK and p38 MAPKs signaling pathways and generation of reactive oxygen species in human breast cancer cells

Wogonin is a one of the bioactive compounds of Scutellaria baicalensi Georgi which has been shown to have antiinflammatory, anticancer, antiviral and neuroprotective effects. However, the underlying mechanisms by which wogonin induces apoptosis in cancer cells still remain speculative. Here we investigated the potential activation of MAPKs and generation of reactive oxygen species (ROS) by wogonin on MCF-7 human breast cancer cells. These results showed that wogonin induced mitochondria and death-receptor-mediated apoptotic cell death, which was characterized by activation of several caspases, induction of PARP cleavage, change of antiapoptotic/proapoptotic Bcl-2 family member ratios and cleavage of Bid. We also found that generation of ROS was an important mediator in wogonin-induced apoptosis. Further investigation revealed that wogonin activated ERK and p38 MAPKs, which was inhibited by N-acetyl cysteine (NAC), a ROS scavenger, indicating that wogonin-induced ROS are associated with MAPKs activation. These data demonstrate that wogonin may be a novel anticancer agent for treatment of breast cancer.

The ethanol extract of Scutellaria baicalensis and the active compounds induce cell cycle arrest and apoptosis including upregulation of p53 and Bax in human lung cancer cells

Despite a lack of scientific authentication, Scutellaria baicalensis is clinically used in Chinese medicine as a traditional adjuvant to chemotherapy of lung cancer. In this study, cytotoxicity assays demonstrated that crude ethanolic extracts of S. baicalensis were selectively toxic to human lung cancer cell lines A549, SK-LU-1 and SK-MES-1 compared with normal human lung fibroblasts. The active compounds baicalin, baicalein and wogonin did not exhibit such selectivity. Following exposure to the crude extracts, cellular protein expression in the cancer cell lines was assessed using 2D gel electrophoresis coupled with MALDI-TOF-MS/Protein Fingerprinting. The altered protein expression indicated that cell growth arrest and apoptosis were potential mechanisms of cytotoxicity. These observations were supported by PI staining cell cycle analysis using flow cytometry and Annexin-V apoptotic analysis by fluorescence microscopy of cancer cells treated with the crude extract and pure active compounds. Moreover, specific immunoblotting identification showed the decreased expression of cyclin A results in the S phase arrest of A549 whereas the G(0)/G(1) phase arrest in SK-MES-1 cells results from the decreased expression of cyclin D1. Following treatment, increased expression in the cancer cells of key proteins related to the enhancement of apoptosis was observed for p53 and Bax. These results provide further insight into the molecular mechanisms underlying the clinical use of this herb as an adjuvant to lung cancer therapy.

Oroxylin A induces G2/M phase cell-cycle arrest via inhibiting Cdk7-mediated expression of Cdc2/p34 in human gastric carcinoma BGC-823 cells

We reported previously that oroxylin A, a natural product isolated from Scutellariae Radix, was a potent apoptosis inducer of human hepatoma HepG2 cells. In this study, cell-cycle arrest of BGC-823 human gastric carcinoma cells caused by oroxylin A has been investigated. Based on our 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay and flow cytometric analysis, treatment of BGC-823 cells with growth suppressive concentrations of oroxylin A caused an irreversible arrest in the G2/M phase of the cell cycle. Western blot analysis demonstrated that oroxylin A-induced cell-cycle arrest in BGC-823 cells was associated with a significant decrease in cdc2/p34, cyclin B1 and cyclin A expression. In addition, oroxylin A-treated cells decreased the expression of Cdk7, which was responsible for the low expression of M phase promoting factor (cyclin B1/Cdc2). The results suggested that oroxylin A induced G2/M phase cell-cycle arrest via inhibiting Cdk7-mediated expression of Cdc2/p34 in human gastric carcinoma BGC-823 cells.

Wogonin induces G1 phase arrest through inhibiting Cdk4 and cyclin D1 concomitant with an elevation in p21Cip1 in human cervical carcinoma HeLa cells

Wogonin, a naturally occurring flavonoid, has been shown to have tumor therapeutic potential both in vitro and in vivo. To better understand its anticancer mechanism, we examined the effect of wogonin on human cervical carcinoma HeLa cells. In this study, we observed that G1 phase arrest was involved in wogonin-induced growth inhibition in HeLa cells. Over a 24 h exposure of HeLa cells to 90 µmol·L–1 wogonin, the promoters of G1–S transition, including cyclin D1/Cdk4 and pRb, decreased within 12 h and E2F-1 depleted in the nucleus at the same time. As the G1 phase arrest developed, p53 and the Cdk inhibitor p21Cip1 elevated both at protein and mRNA levels. Furthermore, the up-regulation of p21Cip1 induced by wogonin was dramatically inhibited by siRNA-mediated p53 gene silencing. Collectively, our data suggested that wogonin induced G1 phase arrest in HeLa cells by modulating several key G1 regulatory proteins, such as Cdk4 and cyclin D1, as well as up-regulation of a p53-midiated p21Cip1 expression. This mechanism of wogonin may play an important role in the killing of cancerous cells and offer a potential mechanism for its anticancer action in vivo.

Reactive oxygen species up-regulate p53 and Puma; a possible mechanism for apoptosis during combined treatment with TRAIL and wogonin

BACKGROUND AND PURPOSE

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptotic death in a variety of cancer cells without marked toxicity to most normal cells. We previously reported that wogonin, a potent anticancer agent from a Chinese herb, up-regulates p53 in prostate cancer cells. In this study, the effects of combinations of TRAIL and wogonin on a human prostate cancer cell line LNCaP, resistant to TRAIL, was evaluated for evidence of synergy in triggering apoptosis.

EXPERIMENTAL APPROACH

Western blot assay and the 'comet' assay were used to study the underlying mechanisms of cell death and search for any mechanisms of enhancement of TRAIL-induced apoptosis in the presence of wogonin.

KEY RESULTS

During combined treatment with wogonin and TRAIL, cytotoxicity, poly(ADP-ribose) polymerase cleavage and caspase activation were associated with up-regulation of p53 through DNA damage and reactive oxygen species (ROS) generation. N-acetylcysteine (NAC), an antioxidant, inhibited ROS generation and synergistic interaction between TRAIL and wogonin. Experimental results in human colon cancer HCT116 cells demonstrated that p53-dependent Puma up-regulation played an important role; deficiency in either p53 or Puma prevented wogonin-enhanced TRAIL-induced apoptosis.

CONCLUSIONS AND IMPLICATIONS

The present studies suggest that wogonin enhances TRAIL-induced cytotoxicity through up-regulation of p53 and Puma, mediated by ROS.

New therapeutic aspects of flavones: the anticancer properties of Scutellaria and its main active constituents Wogonin, Baicalein and Baicalin

Traditional Chinese medicines have been recently recognized as a new source of anticancer drugs and new chemotherapy adjuvant to enhance the efficacy of chemotherapy and to ameliorate the side effects of cancer chemotherapies however their healing mechanisms are still largely unknown. Scutellaria baicalensis is one of the most popular and multi-purpose herb used in China traditionally for treatment of inflammation, hypertension, cardiovascular diseases, and bacterial and viral infections. Accumulating evidence demonstrate that Scutellaria also possesses potent anticancer activities. The bioactive components of Scutellaria have been confirmed to be flavones. The major constituents of Scutellaria baicalensis are 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 antitumor 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. The tumor-selectivity of Wogonin has recently been demonstrated to be due to its ability to differentially modulate the oxidation-reduction status of malignant vs. normal lymphocytic cells and to preferentially induce phospholipase C gamma 1, a key enzyme involved in Ca(2+) signaling, through H(2)O(2) signaling in malignant lymphocytes. This review is aimed to summarize the research results obtained since the last 20 years and to highlight the recently discovered molecular mechanisms.

Wogonin induced differentiation and G1 phase arrest of human U-937 leukemia cells via PKCdelta phosphorylation

Wogonin, a natural monoflavonoid, has been shown to have tumor therapeutic potential in vitro and in vivo. Recently many studies have focused on the induction of apoptosis of tumor cells by wogonin. In this study, we found that wogonin could induce differentiation and G1 phase arrest of human U-937 leukemia cells. The growth of U-937 cells incubated with wogonin was inhibited in a time- and concentration-dependent manner. After treatment with wogonin, U-937 cells exhibited the characteristics of mature granulocytes, such as increased cytoplasmic-to-nuclear ratio, enhanced prominence of cytoplasmic granules, membrane ruffling, a higher NBT-reducing ability, and an increased expression of CD11b. Moreover, wogonin could induce G1 phase arrest and influenced the expression of associated proteins. For example, the expression of phorsphorylated protein kinase C (PKC) delta, p21 increased, while that of cyclin D1/cyclin-dependent kinase (CDK) 4, p-Rb decreased. The upregulation of p21 could be reversed by rottlerin, an inhibitor of PKCdelta. Taken together, wogonin induced U-937 cells to undergo granulocytic differentiation and G1 phase arrest via PKCdelta phosphorylation-induced upregulation of p21 proteins.

Wogonin suppresses tumor growth in vivo and VEGF-induced angiogenesis through inhibiting tyrosine phosphorylation of VEGFR2

Previous studies revealed that wogonin, a naturally occurring monoflavonoid extracted from Scutellariae radix, possessed anticancer activity both in vitro and in vivo. However, the molecular mechanism of its potent anticancer activity remains poorly understood and warrants further investigations. In this study, we found for the first time that wogonin inhibited the growth and tumor angiogenesis of human gastric carcinoma in nude mice. We explored the inhibitory effect of wogonin on angiogenesis stimulated by vascular endothelial growth factor (VEGF) in vitro. Wogonin suppressed the VEGF-stimulated migration and tube formation of human umbilical vein endothelial cells (HUVECs). It also restrained VEGF-induced tyrosine phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2). This inhibition of receptor phosphorylation was correlated with a significant decrease in VEGF-triggered phosphorylated forms of ERK, AKT and p38. Taken together, these findings strongly suggest that wogonin might be a promising antitumor drug.

Differential apoptotic induction of gambogic acid, a novel anticancer natural product, on hepatoma cells and normal hepatocytes

Gambogic acid (GA) is the major active ingredient of gamboge, a brownish resin exuded from Garcinia hanburryi tree in Southeast Asia. In this study, we compared the different apoptotic induction of GA on human normal embryonic hepatic L02 cells and human hepatoma SMMC-7721 cells by detecting growth inhibition, observing morphological changes, and the expressions of the relative apoptotic proteins (Bax, Bcl-2 and caspase-3). The results indicated that GA could selectively induce apoptosis of SMMC-7721 cells, while had relatively less effect on L02 cells. To illustrate the distinct selective antitumor mechanism of GA, we further study its distribution in cultured cells and in tumor-bearing mice. The results indicated that SMMC-7721 cells have higher GA binding activity than L02 cells. The retention time of GA in grafted tumor was longer than in liver, renal and other organs. Collectively, the selective anticancer activity of GA could be due to its significant apoptotic inducing effects as well as its higher distribution and longer retention time in tumor cells compared to the normal cells. So GA might be a kind of highly effective anticancer drug candidate with low toxicity to normal tissue.