Chinese medicinal herb Scutellaria barbata modulates apoptosis and cell survival in murine and human prostate cancer cells and tumor development in TRAMP mice

The Effect of Quercetin in the Yishen Tongluo Jiedu Recipe on the Development of Prostate Cancer through the Akt1-related CXCL12/ CXCR4 Pathway

BACKGROUND

It remains a challenge to effectively treat prostate cancer (PCa) that affects global men's health. It is essential to find a natural alternative drug and explore its antitumor mechanism due to the serious toxic side effects of chemotherapy.

METHODS

The targets and signaling pathways were analyzed by network pharmacology and verified by molecular docking and LC-MS. The proliferation, apoptosis, invasion, and migration of DU145 cells were detected by the CCK-8 method, flow cytometry, and Transwell, respectively. The Bcl-2, caspase-3, CXCL12, and CXCR4 expressions and Akt1 phosphorylation were determined by Western blot. Akt1 overexpression was applied to identify the involvement of the Akt1- related CXCL12/CXCR4 pathway in regulating PCa. Nude mouse tumorigenesis was performed to analyze the effect of quercetin on PCa in vivo.

RESULTS

Network pharmacology analysis displayed that quercetin was the main active component of the Yishen Tongluo Jiedu recipe and Akt1 was the therapy target of PCa. LC-MS analysis showed that quercetin existed in the Yishen Tongluo Jiedu recipe, and molecular docking proved that quercetin bound to Akt1. Quercetin inhibited the proliferation of DU145 cells by upregulating caspase-3 and downregulating Bcl-2 expression, promoting apoptosis and reducing invasion and migration abilities. In vivo, quercetin downregulated CXCL12 and CXCR4 expressions and inhibited PCa development by the Akt1-related CXCL12/CXCR4 pathway.

CONCLUSION

As the active component of the Yishen Tongluo Jiedu recipe, quercetin inhibited PCa development through the Akt1-related CXCL12/CXCR4 pathway. This study provided a new idea for PCa treatment and a theoretical basis for further research.

Systematic investigation of the mechanism of herbal medicines for the treatment of prostate cancer

Due to various unpleasant side effects and general ineffectiveness of current treatments for prostate cancer (PCa), more and more people with PCa try to look for complementary and alternative medicine such as herbal medicine. However, since herbal medicine has multi-components, multi-targets and multi-pathways features, its underlying molecular mechanism of action is not yet known and still needs to be systematically explored. Presently, a comprehensive approach consisting of bibliometric analysis, pharmacokinetic assessment, target prediction and network construction is firstly performed to obtain PCa-related herbal medicines and their corresponding candidate compounds and potential targets. Subsequently, a total of 20 overlapping genes between DEGs in PCa patients and the target genes of the PCa-related herbs, as well as five hub genes, i.e., CCNA2, CDK2, CTH, DPP4 and SRC were determined employing bioinformatics analysis. Further, the roles of these hub genes in PCa were also investigated through survival analysis and tumour immunity analysis. Moreover, to validate the reliability of the C-T interactions and to further explore the binding modes between ingredients and their targets, the molecular dynamics (MD) simulations were carried out. Finally, based on the modularization of the biological network, four signaling pathways, i.e., PI3K-Akt, MAPK, p53 and cell cycle were integrated to further analyze the therapeutic mechanism of PCa-related herbal medicine. All the results show the mechanism of action of herbal medicines on treating PCa from the molecular to systematic levels, providing a reference for the treatment of complex diseases using TCM.

Investigating the Mechanism of Scutellariae barbata Herba in the Treatment of Colorectal Cancer by Network Pharmacology and Molecular Docking

Background

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors, which accounts for approximately 10% of all diagnosed cancers and cancer deaths worldwide per year. Scutellariae barbatae Herba (SBH) is one of the most frequently used traditional Chinese medicine (TCM) in the treatment of CRC. Although many experiments have been carried out to explain the mechanisms of SBH, the mechanisms of SBH have not been illuminated fully. Thus, we constructed a network pharmacology and molecular docking to investigate the mechanisms of SBH.

Methods

We adopted active constituent prescreening, target predicting, protein-protein interaction (PPI) analysis, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, differentially expressed gene analysis, and molecular docking to establish a system pharmacology database of SBH against CRC.

Results

A total of 64 active constituents of SBH were obtained and 377 targets were predicted, and the result indicated that quercetin, luteolin, wogonin, and apigenin were the main active constituents of SBH. Glucocorticoid receptor (NR3C1), pPhosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA), cellular tumor antigen p53 (TP53), transcription factor AP-1 (JUN), mitogen-activated protein kinase 1 (MAPK1), Myc protooncogene protein (MYC), cyclin-dependent kinase 1 (CDK1), and broad substrate specificity ATP-binding cassette transporter ABCG2 (ABCG2) were the major targets of SBH in the treatment of CRC. GO analysis illustrated that the core biological process regulated by SBH was the regulation of the cell cycle. Thirty pathways were presented and 8 pathways related to CRC were involved. Molecular docking presented the binding details of 3 key targets with 6 active constituents.

Conclusions

The mechanisms of SBH against CRC depend on the synergistic effect of multiple active constituents, multiple targets, and multiple pathways.

Scutellaria barbata: A Review on Chemical Constituents, Pharmacological Activities and Clinical Applications

Scutellaria barbata has a long history of medical use in Traditional Chinese Medicine for removing heat and toxic material, promoting blood circulation and removing blood stasis, and inducing diuresis to reduce edema. Recent pharmacology investigations have provided evidence for its anti-cancer, bacteriostasis, anti-virus, anti-inflammation, anti-oxidation and immunity enhancement properties. The efficacy of activating blood circulation and removing blood stasis has unique advantages in the treatment of cardiovascular and cerebrovascular diseases. A total of 84 compounds have been isolated from S. barbata and are characterized mainly as flavonoids, diterpenoids, followed by polysaccharide, volatile oil and steroids. Peer-reviewed articles published over the last few years were gathered by consulting the databases PubMed, Elsevier, Springer, and Chinese Herbal Classics. This review mainly focuses on the pharmacologically active constituents isolated from S. barbata，which have been subjected to in vitro and/or in vivo studies. Although, the chemical components, pharmacological activities, toxicology, clinical applications and mechanisms of action of S. barbata have been investigated, many constituents remain unknown. Further investigations are required to investigate the medicinal properties of S. barbata.

Effectiveness of Scutellaria barbata water extract on inhibiting colon tumor growth and metastasis in tumor-bearing mice

The plant Scutellaria barbata (SB) is commonly used as herbal medicines for treating cancer. The present pre-clinical study aimed to validate the Chinese Pharmacopoeia (CP) recommended dosages of SB water extract (SBW) in treating colon tumors. The content of chemical marker scutellarin in SBW was quantified using UPLC. Mice bearing human HCT116 xenografts or murine colon26 tumors received oral administration of SBW or scutellarin for 4 weeks. Results showed that SBW (615 and 1,230 mg/kg) and scutellarin (7 mg/kg) treatments significantly reduced human xenograft weights by 28.7, 36.9 and 28.8%, respectively. Lung metastasis area could be ameliorated after SBW (615 mg/kg) and scutellarin (7 mg/kg) treatments by 23.4 and 29.5%, respectively. Expressions of colon cancer metastasis-related proteins E-cadherin, Tspan 8 and CXCR4, as well as Src kinase in tumors were first shown to be regulated by SBW. Furthermore, in murine colon26 tumor-bearing mice, SBW (615 mg/kg) and scutellarin (7 mg/kg) treatments reduced the orthotopic tumor burden by 94.7% and lung metastatic tumor burden by 94.1%, respectively. Our findings provided evidences that SBW (at the mouse equivalent dosages to clinical dosages recommended by CP) could exert anti-tumor and anti-metastatic effects in colon cancer animal models.

A review of the ethnopharmacology, phytochemistry, pharmacology, and quality control of Scutellaria barbata D. Don

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria barbata D. Don (S. barbata) is a well-known perennial herb that is used in traditional Chinese and Korean medicine. In China, it is known as Ban Zhi Lian, while in Korea, it is known as Banjiryun. In the Traditional Chinese Medicine (TCM) system, S. barbata has heat-clearing and detoxifying properties (Qingre Jiedu in Chinese).

AIM OF THE REVIEW

To provide a systematic review on current multifaceted understanding of S. barbata, with particular emphasis on the correlation between its traditional applications and pharmacological activities.

MATERIALS AND METHODS

All available S. barbata-related information from internet databases, including PubMed, Science Direct, Elsevier, China National Knowledge Internet, and Google Scholar (up to October 2018) were searched. Additional information was gathered from classical books on Chinese Herbals, Chinese Pharmacopoeia, and so on.

RESULTS

In the TCM system, S. barbata is mainly prescribed for its heat-clearing and detoxifying effects. More than 203 compounds have been isolated and identified from this herb, with neo-clerodane diterpenoids and flavonoids as the main compounds. Most neo-clerodanes have been demonstrated to have cytotoxic effects against different cancer cell types in vitro. The S. barbata extracts exhibited anti-inflammatory, anti-microbial, antitumor, and other pharmacological activities. To add, flavonoids, including wogonin, baicalein, apigenin, naringenin, and scutellarin, were identified as the key to quality control.

CONCLUSIONS

The heat-clearing effects of S. barbata could be attributed to its anti-inflammatory and hepatoprotective activities, whereas its detoxifying effects might be due to the anti-microbial functions of neo-clerodane diterpenoids and flavones. S. barbata may display anti-tumor effects and through active ingredient analysis, neo-clerodane diterpenoids are suggested to be its representative compounds. Overall, many pre-clinical studies have been conducted but very little concrete evidences are available on its specific effects, which are of therapeutic relevance.

Transcriptional regulation of G2/M regulatory proteins and perturbation of G2/M Cell cycle transition by a traditional Chinese medicine recipe

ETHNOPHARMACOLOGICAL RELEVANCE

Hedyotis diffusa Willd. (H) and Scutellaria barbata D.Don (S) are ancient anti-cancer Chinese herb medicines. When combined, known as HS, it is one of the most commonly prescribed Chinese Medicines for cancer patients today in China.

AIM OF THE STUDY

The prevention of disease progression is a dominant concern for the growing number of men with prostate cancer. The purpose of this work is to evaluate the action and mode of action of Chinese Medicine recipe HS in inhibiting prostate cancer progression in preclinical models.

METHODS

Effects of HS were analyzed in prostate cancer cell lines by evaluating proliferation, cell cycle profile, DNA damage and key regulators responsible for G₂ to M phase transition. The transcriptional activities of these regulators were determined by RT-PCR and ChIP. The efficacy of HS in vitro was validated in an animal model.

RESULTS

HS treatment was observed to reduce DNA content and accumulated prostate cancer cells at the G₂/M phase. Immunolabeling for phospho-Histone H3 in association with nocodazole to capture mitotic cells confirmed that HS impeded G₂ to M transition. After excluding DNA damage-induced G₂ arrest, it was revealed that HS reduced expression of Cyclin B1, CDK1, PLK1 and Aurora A at both protein and mRNA levels, with concomitant reduction of H3K4 tri-methylation at their promoter-regions. Animals that received oral administration of HS with a dosage relevant to clinical application showed reduced tumor volume and weight with a reduction of Cyclin B1, CDK1, PLK1 and Aurora A protein levels.

CONCLUSIONS

HS acts by impeding the G₂ to M transition of prostate cancer cells. It is likely that the mode of action is transcriptionally suppressing proteins governing mitotic entry, without eliciting significant DNA damage.

Chinese Medicines in the Treatment of Prostate Cancer: From Formulas to Extracts and Compounds

In order to fully understand the progresses and achievements in Chinese medicines for the treatment of prostate cancer, we summarize all the available reports on formulas, extracts, and compounds of Chinese medicines against prostate cancer. A number of clinical trials verified that traditional Chinese formulas had some unique advantages in the treatment of prostate cancer. Many Chinese medicine extracts could protect against prostate cancer, and many compounds isolated from Chinese traditional medicines showed a clear anti-prostate cancer effect. However, Chinese medicines are facing many problems regarding their multicomponent nature, complicated mechanisms of action, and high doses required for therapy. Herein, we review the functions of Chinese medicines in prostate cancer and focus on their mechanisms. The review will deepen the understanding of Chinese medicines potential in the anti-prostate cancer field. In addition, we put forward a question concerning the current research on Chinese medicines: in order to better illustrate that Chinese medicines can be used in the clinical treatment of prostate cancer, should our research focus on formulas, extracts, or compounds?

Scutellaria barbata D. Don inhibits migration and invasion of colorectal cancer cells via suppression of PI3K/AKT and TGF-β/Smad signaling pathways

Metastasis is one of the most aberrant behaviors of cancer cells. Patients with cancers, including colorectal cancer (CRC), have a higher risk of tumor recurrence and cancer-related mortality once metastasis is diagnosed. Existing treatment strategies fail to cure cancer mostly due to the onset of metastasis. Therefore, metastasis remains a challenge in cancer treatment. Some complementary and alternative medical therapies using traditional Chinese medicine have been demonstrated to be clinically effective in cancer treatment. Scutellaria barbata D. Don (SB) is a promising medicinal herb. It was previously reported that the ethanol extract of SB (EESB) is able to promote apoptosis, and inhibit cell proliferation and angiogenesis in human colon cancer cells. However, the anticancer effect of SB and the underlying mechanism require further investigation, particularly its role against metastasis. To further elucidate the antimetastatic effect of SB, MTT and Transwell assays were used in the present study to evaluate the effect of EESB on the proliferation, migration and invasion of the CRC cell line HCT-8. In addition, western blot analysis was performed to detect the expression of matrix metalloproteinases (MMPs), cadherins and other metastasis-associated proteins. EESB significantly reduced HCT-8 cell viability and attenuated the migration and invasion ability of HCT-8 cells in a dose-dependent manner. In addition, EESB decreased the expression of MMP-1, MMP-2, MMP-3/10, MMP-9 and MMP-13, and proteins in the phosphoinositide 3-kinase (PI3K)/AKT and transforming growth factor (TGF)-β/Smad pathways, but not the epithelial-mesenchymal transition (EMT)-related factors E-cadherin and N-cadherin. In conclusion, the results suggested that SB inhibits CRC cell metastasis via the suppression of PI3K/AKT and TGF-β/Smad signaling pathways, which may represent a mechanism by which SB exerts an anticancer effect.

Herbal Compound Songyou Yin and Moderate Swimming Suppress Growth and Metastasis of Liver Cancer by Enhancing Immune Function

Objective. Both the Chinese herbal compound Songyou Yin (SYY) and swimming exercise have been shown to have protective effects against liver cancer in animal models. In this study, we investigated whether SYY and moderate swimming (MS) have enhanced effect on suppressing progression of liver cancer by immunomodulation. Methods. C57BL/6 mice were transplanted with Hepa1-6 murine liver cancer cell lines and received treatment with SYY alone or SYY combined with MS. The green fluorescent protein (GFP)-positive metastatic foci in lungs were imaged with a stereoscopic fluorescence microscope. Flow cytometry was used to test the proportion of CD4 +, CD8 + T cells in peripheral blood and the proportions of CD4 + CD25 + Foxp3 + Treg cells in peripheral blood, spleen, and tumor tissues. Cytokine transforming growth factor (TGF)-β1 level in serum was detected by ELISA. Results. SYY plus MS significantly suppressed the growth and lung metastasis of liver cancer and prolonged survival in tumor-burdened mice. SYY plus MS markedly raised the CD4 to CD8 ratio in peripheral blood and lowered the serum TGF-β1 level and the proportions of Treg cells in peripheral blood, spleen, and tumor tissue. The effects of the combined intervention were significantly superior to SYY or MS alone. Conclusion. The combined application of SYY and MS exerted an enhanced effect on suppressing growth and metastasis of liver cancer by strengthening immunity.

Using the Gene Expression Signature of Scutebarbalactone VN Isolated from Scutellaria barbata to Elucidate its Anticancer Activities

Bioassay-guided fractionation led to the discovery of a novel neo-clerodane diterpenoid, scutebarbalactone VN (BalA: 8,13-epoxy-3-en-7-hydroxy-6,11- O-dibenzoyl-15,16-clerodanolide), from the methanol extract of the whole-plant of Vietnamese Scutellaria barbata D. Don. A microarray technique combined with bioinformatic analyses showed that BalA could inhibit cell cycle pathways by downregulating genes such as CDC25A and AURKA. BalA also showed the potential to reactivate downregulated genes in hepatocellular carcinoma cells and genes in antioxidant pathways such as HMOX1 and HSPA1A. Querying Connectivity map 2.0 resulted in a match of the BalA-modulated gene signature with that of 10 known compounds, most of which are currently marketed chemotherapy drugs. The highest matching scores belonged to lomustine, semustine, and withaferin A. Lomustine and semustine were found to alkylate DNA and RNA, while withaferin A inhibits nuclear factor kappa B (NF-κB) activity. A luciferase reporter assay was also conducted on 293/NF-κB human embryonic kidney cells that had been transfected with the NF-κB-luciferase plasmid to verify the anticancer activity of BalA. The assay showed that Ba1A effectively blocked NF-κB with an IC50 of 38.6 ± 0.05 μM.

Selective anticancer effects and protection from chemotherapy by the botanical compound LCS101: Implications for cancer treatment

There is a need for new options for reducing the side effects of cancer treatment, without compromising efficacy, enabling patients to complete treatment regimens. The botanical compound LCS101 exhibits inhibitory effects on cancer cell growth, and reduces chemotherapy-induced hematological toxicities. The aim of the present study is to examine the selectivity of the effects of the compound, alone and in conjunction with conventional chemotherapy agents, on cancer cell proliferation. The effects of LCS101 were tested on a number of cancer cell lines (breast, MCF7, MDA-MB‑231; colorectal, HCT116; prostate, PC-3, DU-145) and on non-tumorigenic normal human epithelial cells (breast, MCF10A; prostate, EP#2). Cell viability was analyzed using an XTT assay and observed by light microscopy. Necrosis and apoptosis were examined using FACS analysis and immunoblotting. LCS101 selectively induced cell death in breast, colon and prostate cancer cell lines, as measured by XTT assay. Light microscopy and FACS analysis showed changes indicative of a necrotic process. LCS101 was also found to induce PARP-1 reduction in breast cancer cells, with no effect on non-tumorigenic breast epithelial cells. While LCS101 increased cell death in cancer cells exposed to doxorubicin and 5-FU, it showed a protective effect on non-tumorigenic human epithelial cells from chemotherapy-induced cell death. A similar selective effect was observed with apoptosis-associated PARP-1 cleavage. The findings demonstrate that the anti-proliferative effects exhibited by the botanical compound LCS101 are selective to cancer cells, and offer protection to non-tumorigenic normal epithelial cells from chemotherapy agents.

Two new neoclerodane diterpenoids from Scutellaria barbata D. Don growing in Vietnam

Various chromatographic separations of the aerial parts of Scutellaria barbata afforded two new neoclerodane diterpenoids, scutebatas S and T (1 and 2), along with scutebata D (3). Their structures were elucidated by spectroscopic methods including high-resolution electrospray ionization mass spectrometry, 1D and 2D NMR and comparison with the literature values. Compounds 1 and 3 exhibited moderate cytotoxic activities against HL-60 (promyeloblast) human cancer cells. Weak cytotoxic effects toward four tested human cancer cell lines including KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), MCF7 (breast cancer), and Hep-G2 (hepatoma cancer) were observed for 1 and 3; whereas 2 was inactive on all five tested cell lines.

Cancer Prevention and Therapy: Integrating Traditional Korean Medicine Into Modern Cancer Care

In spite of billions of dollars spent on cancer research each year, overall cancer incidence and cancer survival has not changed significantly in the last half century. Instead, the recent projection from the World Health Organization suggests that global cancer incidence and death is expected to double within the next decade. This requires an "out of the box" thinking approach. While traditional medicine used for thousands of years is safe and affordable, its efficacy and mechanism of action are not fully reported. Demonstrating that traditional medicine is efficacious and how it works can provide a "bed to bench" and "bench to bed" back approach toward prevention and treatment of cancer. This current review is an attempt to describe the contributions of traditional Korean medicine (TKM) to modern medicine and, in particular, cancer treatment. TKM suggests that cancer is an outcome of an imbalance of body, mind, and spirit; thus, it requires a multimodal treatment approach that involves lifestyle modification, herbal prescription, acupuncture, moxibustion, traditional exercise, and meditation to restore the balance. Old wisdoms in combination with modern science can find a new way to deal with the "emperor of all maladies."

Scutellaria barbata D. Don induces G1/S arrest via modulation of p53 and Akt pathways in human colon carcinoma cells

Cancer cells are characterized by an uncontrolled increase in cell proliferation. G1 to S transition is one of the two main checkpoints used by cells to control the cell cycle progress and cell proliferation. G1/S progression is highly regulated by multiple intracellular signaling transduction cascades including Akt and p53 pathways, which therefore becomes a promising target for the development of novel anticancer therapy. Scutellaria barbata D. Don (SB) is a major component in many Chinese medicine formulas that have long been used in China to clinically treat various cancers including colorectal cancer (CRC). Recently, we reported that the ethanol extract of SB (EESB) is able to induce cancer cell apoptosis via activation of the mitochondrion-dependent pathway and inhibit tumor angiogenesis through suppression of Hedgehog signaling. To further elucidate the precise mechanisms of its antitumor activity, in the present study we evaluated the effect of EESB on the proliferation of human colon carcinoma HT-29 cells and investigated the underlying molecular mechanism. We found that EESB could inhibit the proliferation of HT-29 cells through blocking the G1/S cell cycle progression. In addition, EESB treatment profoundly promoted antiproliferative p21 expression, but inhibited the expression of pro-proliferative PCNA, cyclin D1 and CDK4 in HT-29 cells. Moreover, the phosphorylation/activation of Akt was significantly suppressed by EESB treatment, whereas that of p53 was enhanced. These results suggest that EESB could effectively induce G1/S arrest in human colon carcinoma cells via modulation of multiple cell cycle-related signaling pathways.

Scutellaria barbata D. Don inhibits tumor angiogenesis via suppression of Hedgehog pathway in a mouse model of colorectal cancer

Angiogenesis, which plays a critical role during tumor development, is tightly regulated by the Sonic Hedgehog (SHH) pathway, which has been known to malfunction in many types of cancer. Therefore, inhibition of angiogenesis via modulation of the SHH signaling pathway has become very attractive for cancer chemotherapy. Scutellaria barbata D. Don (SB) has long been used in China to treat various cancers including colorectal cancer (CRC). Our published data suggested that the ethanol extract of SB (EESB) is able to induce apoptosis of colon cancer cells and inhibit angiogenesis in a chick embryo chorioallantoic membrane model. To further elucidate the precise mechanisms of its anti-tumor activity, in the present study we used a CRC mouse xenograft model to evaluate the effect of EESB on tumor growth and angiogenesis in vivo. Our current data indicated that EESB reduces tumor size without affecting on the body weight gain in CRC mice. In addition, EESB treatment suppresses the expression of key mediators of the SHH pathway in tumor tissues, which in turn resulted in the inhibition of tumor angiogenesis. Furthermore, EESB treatment inhibits the expression of vascular endothelial growth factor A (VEGF-A), an important target gene of SHH signaling and functioning as one of the strongest stimulators of angiogenesis. Our findings suggest that inhibition of tumor angiogenesis via suppression of the SHH pathway might be one of the mechanisms by which Scutellaria barbata D. Don can be effective in the treatment of cancers.

Bezielle selectively targets mitochondria of cancer cells to inhibit glycolysis and OXPHOS

Bezielle (BZL101) is a candidate oral drug that has shown promising efficacy and excellent safety in the early phase clinical trials for advanced breast cancer. Bezielle is an aqueous extract from the herb Scutellaria barbata. We have reported previously that Bezielle was selectively cytotoxic to cancer cells while sparing non-transformed cells. In tumor, but not in non-transformed cells, Bezielle induced generation of ROS and severe DNA damage followed by hyperactivation of PARP, depletion of the cellular ATP and NAD, and inhibition of glycolysis. We show here that tumor cells' mitochondria are the primary source of reactive oxygen species induced by Bezielle. Treatment with Bezielle induces progressively higher levels of mitochondrial superoxide as well as peroxide-type ROS. Inhibition of mitochondrial respiration prevents generation of both types of ROS and protects cells from Bezielle-induced death. In addition to glycolysis, Bezielle inhibits oxidative phosphorylation in tumor cells and depletes mitochondrial reserve capacity depriving cells of the ability to produce ATP. Tumor cells lacking functional mitochondria maintain glycolytic activity in presence of Bezielle thus supporting the hypothesis that mitochondria are the primary target of Bezielle. The metabolic effects of Bezielle towards normal cells are not significant, in agreement with the low levels of oxidative damage that Bezielle inflicts on them. Bezielle is therefore a drug that selectively targets cancer cell mitochondria, and is distinguished from other such drugs by its ability to induce not only inhibition of OXPHOS but also of glycolysis. This study provides a better understanding of the mechanism of Bezielle's cytotoxicity, and the basis of its selectivity towards cancer cells.

Photo-activated pheophorbide-a, an active component of Scutellaria barbata, enhances apoptosis via the suppression of ERK-mediated autophagy in the estrogen receptor-negative human breast adenocarcinoma cells MDA-MB-231

AIM OF THE STUDY

Scutellaria barbata is a traditional Chinese medicine for cancer treatments. Pheophorbide-a (Pa), one of the active components isolated from this herbal medicine has been proposed to be a potential natural photosensitizer for photodynamic therapy. The anti-tumor effect of pheophorbide-a based photodynamic therapy (Pa-PDT) has been successfully demonstrated in a wide range of human malignant cell lines. However, the effectiveness of Pa-PDT has not yet been evaluated on human breast cancer, which is documented as the second common and the fifth most lethal cancer worldwide.

MATERIALS AND METHODS

The cytotoxicity of Pa-PDT was evaluated by using an estrogen receptor (ER)-negative human breast adenocarcinoma cell line MDA-MB-231. The involvement of mitochondria was revealed by the change of mitochondrial membrane potential and the increase of intracellular reactive oxygen species (ROS). The hallmarks of apoptosis, ER stress and autophagy were also assessed by DNA fragmentation, Western blotting, and immunostaining assays.

RESULTS

Pa-PDT showed inhibitory effect on the growth of MDA-MB-231 cells with an IC(50) value of 0.5 microM at 24h. Mitogen-activated protein kinase (MAPK) pathway was found to be triggered, where activation of c-Jun N-terminal kinase (JNK) and inhibition of extracellular signal-regulated kinase (ERK) were occurred in the Pa-PDT-treated cells. Our findings suggested that Pa-PDT exhibited its anti-tumor effects by the activation of mitochondria-mediated apoptosis and the ERK-mediated autophagy in MDA-MB-231 cells.

CONCLUSION

The present study suggested Pa-PDT is a potential protocol for the late phase human breast cancer, and it is the first study to demonstrate the Pa-PDT induced autophagy contributed to the anti-tumor effects of Pa-PDT on human cancer cells.

A preliminary study: the anti-proliferation effect of salidroside on different human cancer cell lines

Salidroside (p-hydroxyphenethyl-beta-d-glucoside), which is present in all species of the genus Rhodiola, has been reported to have a broad spectrum of pharmacological properties. The present study, for the first time, focused on evaluating the effects of the purified salidroside on the proliferation of various human cancer cell lines derived from different tissues, and further investigating its possible molecular mechanisms. Cell viability assay and [(3)H] thymidine incorporation were used to evaluate the cytotoxic effects of salidroside on cancer cell lines, and flow cytometry analyzed the change of cell cycle distribution induced by salidroside. Western immunoblotting further studied the expression changes of cyclins (cyclin D1 and cyclin B1), cyclin-dependent kinases (CDK4 and Cdc2), and cyclin-dependent kinase inhibitors (p21(Cip1) and p27(Kip1)). The results showed that salidroside inhibited the growth of various human cancer cell lines in concentration- and time-dependent manners, and the sensitivity to salidroside was different in those cancer cell lines. Salidroside could cause G1-phase or G2-phase arrest in different cancer cell lines, meanwhile, salidroside resulted in a decrease of CDK4, cyclin D1, cyclin B1 and Cdc2, and upregulated the levels of p27(Kip1) and p21(Cip1). Taken together, salidroside could inhibit the growth of cancer cells by modulating CDK4-cyclin D1 pathway for G1-phase arrest and/or modulating the Cdc2-cyclin B1 pathway for G2-phase arrest.