Polyphyllin D Exerts Potent Anti-tumour Effects on Lewis Cancer Cells under Hypoxic Conditions

SOX7 is involved in polyphyllin D-induced G0/G1 cell cycle arrest through down-regulation of cyclin D1

The incidence of mortality of prostate cancer (PCa) has been an uptrend in recent years. Our previous study showed that the sex-determining region Y-box 7 (SOX7) was low-expressed and served as a tumor suppressor in PCa cells. Here, we describe the effects of polyphyllin D (PD) on proliferation and cell cycle modifications of PCa cells, and whether SOX7 participates in this process. PC-3 cells were cultured in complete medium containing PD for 12, 24, and 48 h. MTT assay was used to investigate the cytotoxic effects of PD. Cell cycle progression was analyzed using propidium iodide (PI) staining, and protein levels were assayed by Western blot analysis. Our results showed low expression of SOX7 in PCa tissues/cells compared to their non-tumorous counterparts/RWPE-1 cells. Moreover, PD inhibited the proliferation of PC-3 cells in a dose- and time-dependent manner. PD induced G0/G1 cell cycle arrest, while co-treatment with short interfering RNA targeting SOX7 (siSOX7) had reversed this effect. PD downregulated SOX7, cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin-dependent kinase 6 (CDK6) expressions in a dose-dependent manner, whereas co-treatment of siSOX7 and PD rescued the PD-inhibited cyclin D1 expression. However, no obvious changes were observed in CDK4 or CDK6 expression. These results indicate that SOX7 is involved in PD-induced PC-3 cell cycle arrest through down-regulation of cyclin D1.

Assessing the Current State of Lung Cancer Chemoprevention: A Comprehensive Overview

Chemoprevention of lung cancer is thought to significantly reduce the risk of acquiring these conditions in the subpopulation of patients with underlying health issues, such as chronic obstructive pulmonary disorder and smoking-associated lung problems. Many strategies have been tested in the previous decades, with very few translating to successful clinical trials in specific subpopulations of patients. In this review, we analyze these strategies, as well as new approaches that have emerged throughout the last few years, including synthetic lethality concept and microbiome-induced regulation of lung carcinogenesis. Overall, the continuous effort in the area of lung chemoprevention is required to develop practical therapeutical approaches. Given the inconsistency of results obtained in clinical trials targeting lung cancer chemoprevention in various subgroups of patients that differ in the underlying health condition, race, and gender, we believe that individualized approaches will have more promise than generalized treatments.

Paris Saponin I Sensitizes Gastric Cancer Cell Lines to Cisplatin via Cell Cycle Arrest and Apoptosis

BACKGROUND Dose-related toxicity is the major restriction of cisplatin and cisplatin-combination chemotherapy, and is a challenge for advanced gastric cancer treatment. We explored the possibility of using Paris saponin I as an agent to sensitize gastric cancer cells to cisplatin, and examined the underlying mechanism. MATERIAL AND METHODS Growth inhibition was detected by MTT assay. The cell cycle and apoptosis were detected using flow cytometry and Annexin V/PI staining. The P21waf1/cip1, Bcl-2, Bax, and caspase-3 protein expression were detected using Western blot analysis. RESULTS The results revealed that PSI sensitized gastric cancer cells to cisplatin, with low toxicity. The IC50 value of cisplatin in SGC-7901 cell lines was decreased when combined with PSI. PSI promoted cisplatin-induced G2/M phase arrest and apoptosis in a cisplatin concentration-dependent manner. Bcl-2 protein expression decreased, but Bax, caspase-3, and P21waf1/cip1 protein expression increased with PSI treatment. CONCLUSIONS The underlying mechanism of Paris saponin I may be related to targeting the apoptosis pathway and cell cycle blocking, which suggests that PSI is a potential therapeutic sensitizer for cisplatin in treating gastric cancer.

Saponins from Chinese Medicines as Anticancer Agents

Saponins are glycosides with triterpenoid or spirostane aglycones that demonstrate various pharmacological effects against mammalian diseases. To promote the research and development of anticancer agents from saponins, this review focuses on the anticancer properties of several typical naturally derived triterpenoid saponins (ginsenosides and saikosaponins) and steroid saponins (dioscin, polyphyllin, and timosaponin) isolated from Chinese medicines. These saponins exhibit in vitro and in vivo anticancer effects, such as anti-proliferation, anti-metastasis, anti-angiogenesis, anti-multidrug resistance, and autophagy regulation actions. In addition, related signaling pathways and target proteins involved in the anticancer effects of saponins are also summarized in this work.

Anticancer Effects of Paris Saponins by Apoptosis and PI3K/AKT Pathway in Gefitinib-Resistant Non-Small Cell Lung Cancer

Background

Paris saponins have been studied for their anticancer effects in various cancer types, but the mechanisms underlying the cytotoxic effects, especially in EGFR-TKI-resistant cells, are still unclear. We explored the potential mechanism of the antitumor effects of PSI, II, VI, VII in EGFR-TKI-resistant cells and attempted to develop PSI, II, VI, VII as a systemic treatment strategy for EGFR-TKI-resistant lung cancer.

Material/Methods

Growth inhibition was detected by MTT assay. The apoptosis assay was detected using annexin-V/PI and Hoechst staining. The level of PI3K, pAKT, Bax, Bcl-2, caspase-3, and caspase-9 protein expression were detected using Western blot analysis.

Results

The results revealed that PSI, II, VI, VII inhibited the proliferation of PC-9-ZD cells. Furthermore, PSI, II, VI, VII induced significant cell apoptosis. The levels of PI3K, pAKT, Bcl-2 protein decreased, while the Bax, caspase-3, and caspase-9 protein was increased by PSI, II, PSVI, PSVII treatment and resulted in increased sensitivity to gefitinib in PC-9-ZD cells.

Conclusions

The underlying mechanism of Paris saponins may be related to targeting the PI3K/AKT pathways to cause apoptosis. Our results suggest a therapeutic potential of Paris saponins in clinical settings for gefitinib-resistant NSCLC.

An approach combining real-time release testing with near-infrared spectroscopy to improve quality control efficiency of Rhizoma paridis

Raw material examination is a critical process in the industrial production of traditional Chinese medicine (TCM); high accuracy and minimal time consumption are both required. In this study, near-infrared (NIR) spectroscopy was applied to improve the quality control efficiency of Rhizoma paridis. Partial least squares regression (PLSR) was first used to develop quantitative calibration models, and the discriminant analysis model was established to qualitatively discriminate the qualified samples from the unqualified samples. These two established NIR models were applied for real-time release testing (RTRT) of R. paridis. R. paridis saponins (RPS)≥0.6% and moisture ≤12% were used as the quantitative releasing criteria of RTRT according to the Chinese Pharmacopoeia. Qualified samples classified by the discriminant analysis model were deemed to meet the qualitative releasing criterion of RTRT. Using the established quantitative model, 24 samples were allowed to be released to the subsequent production processes with 100% accuracy. For the qualitative RTRT analysis, three samples were misclassified as the unqualified class and were released unsuccessfully, the accuracy of the qualitative RTRT was 90%. Therefore, the quantitative RTRT was more feasible for actual manufacturing processes. Based on this study, a rapid and effective quantitative NIR spectroscopic method was proposed for the RTRT of R. paridis. The combination of RTRT and NIR spectroscopy could be a potential tool to improve the quality control efficiency of R. paridis.

Cytotoxic saponin poliusaposide from Teucrium polium

Three saponin glycosides have been isolated and characterized from Teucrium polium L. (Lamiaceae).

Inhibition of cell proliferation by mild hyperthermia at 43˚C with Paris Saponin I in the lung adenocarcinoma cell line PC-9

Rhizoma paridis is widely used for cancer therapy due to its potential involvement in the suppression of tumor growth. However, at present there is no clear explanation for the mechanism underlying the inhibitory effects of Rhizoma paridis combined with hyperthermia on tumor growth. The aim of the present study was to evaluate the effects of Paris saponin I (PSI) combined with hyperthermia on a variety of non-small cell lung cancer (NSCLC) cell lines. An MTT assay was used to determine the levels of growth inhibition. The cell cycle was analyzed using flow cytometry and cell apoptosis was analyzed with Annexin V/propidium iodide staining and the Hoechst assay. The morphology of cells during apoptosis was determined using a transmission electron microscope. The expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase-3 proteins were detected using western blotting. The inhibition rates significantly increased with PSI in combination with hyperthermia at 43˚C. PSI with hyperthermia at 43˚C caused G2/M phase arrest and significantly induced apoptosis. The expression level of Bcl-2 decreased, while Bax expression increased following treatment with PSI with hyperthermia at 43˚C. In addition, the protein expression of caspase-3 was significantly enhanced. PSI combined with hyperthermia is a potent antitumor treatment through the inhibition of proliferation of NSCLC cells and may be developed as a new antitumor therapy. PSI combined with hyperthermia significantly induced apoptosis through a multi regulatory process involving G2/M arrest and regulation of Bax, Bcl-2 and caspase-3 expression, resulting in cell death and tumor inhibition.

Polyphyllin D induces apoptosis in U87 human glioma cells through the c-Jun NH2-terminal kinase pathway

Polyphyllin D (PD), an active component from a traditional medicinal herb Paris polyphylla, which has long been used for the treatment of cancer in Asian countries, has been found to hold significant antitumor activity in vivo or in vitro. However, there were few reports on the effects and underlying mechanism of PD on apoptosis in U87 human glioma cells. The present study was conducted to evaluate apoptotic induction of PD in U87 human glioma cells, and explore its underlying pathway. U87 glioma cells were cultured and treated with varied concentrations of PD (from 10(-8) to 10(-4) M). The inhibition of U87 glioma cell proliferation by PD was assessed by MTT assay. The apoptosis of U87 glioma cells was detected by flow cytometry, and western blot analysis was used to examine human B-cell leukemia/lymphoma 2 (Bcl-2), human Bcl-2 associated X protein (Bax), caspase-3, total-c-jun NH2-terminal kinase (t-JNK), and phosphorylation-JNK (p-JNK) protein expression in U87 human glioma cells. The treatment with PD for 24 h significantly inhibited the proliferation of U87 human glioma cells in a concentration-dependent manner. PD increased apoptosis and significantly upregulated the expression of Bax, caspase-3, and p-JNK associated with apoptosis, but downregulated antiapoptotic Bcl-2 expression in U87 human glioma cells. Our data provided evidences that PD induces apoptosis in U87 human glioma cells. This effect might be associated with the JNK pathway.

The anti-lung cancer activities of steroidal saponins of P. polyphylla Smith var. chinensis (Franch.) Hara through enhanced immunostimulation in experimental Lewis tumor-bearing C57BL/6 mice and induction of apoptosis in the A549 cell line

P. polyphylla Smith var. chinensis (Franch.) Hara (PPSCFH) has been used as medicinal Paris for the prevention and treatment of cancers in China for thousands of years. Its main components, steroidal saponins (PRS), have been confirmed to inhibit tumor growth. In the present study, the immunostimulation of PRS was investigated in Lewis bearing-C57BL/6 mice while the induction of apoptosis in A549 cells was also studied. The treatment with PRS (2.5, 5.0 and 7.5 mg/kg) significantly inhibited tumor, volume, and weight in the C57BL/6 mice. The rates of inhibition of PRS (at 2.5, 5.0 and 7.5 mg/kg) were 26.49 ± 17.30%, 40.32 ± 18.91% and 54.94 ± 16.48%, respectively. The spleen and thymus indexes were increased remarkably, while the levels of inflammatory cytokines including TNF-α, IL-8 and IL-10 in serum were decreased according to ELISA assays. For A549 cells, Hoechst 33342 staining and annexin V/PI by flow cytometry showed that PRS (0.25, 0.50 and 0.75 mg/mL) induced nuclear changes of A549 cells with DNA condensation and fragmentations of chromatin, as well as inducing apoptosis. Furthermore, PRS could also attenuate the over-generation of intracellular ROS. Western blotting analysis showed a significant decrease on the expressions of proinflammatory cytokines MCP-1, IL-6 and TGF-β1, as well as cell adhesion molecule ICAM-1, by treatment with PRS. Our results demonstrated that the inhibition of PRS on tumor growth might be associated with the amelioration of inflammation responses, induction of apoptosis, as well as the decrease of ROS. These results suggested that PRS implied a potential therapeutic effect in the lung cancer treatment.

Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression

Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs.

Fighting fire with fire: poisonous Chinese herbal medicine for cancer therapy

ETHNOPHARMACOLOGICAL RELEVANCE

Following the known principle of "fighting fire with fire", poisonous Chinese herbal medicine (PCHM) has been historically used in cancer therapies by skilled Chinese practitioners for thousands of years. In fact, most of the marketed natural anti-cancer compounds (e.g., camptothecin derivatives, vinca alkaloids, etc.) are often known in traditional Chinese medicine (TCM) and recorded as poisonous herbs as well. Inspired by the encouraging precedents, significant researches into the potential of novel anticancer drugs from other PCHM-derived natural products have been ongoing for several years and PCHM is increasingly being recognized as a gathering place for promising anti-cancer drugs. The present review aimed at giving a rational understanding of the toxicity of PCHM and, especially, providing the most recent developments on PCHM-derived anti-cancer compounds.

MATERIALS AND METHODS

Information on the toxicity and safety control of PCHM, as well as PCHM-derived anti-cancer compounds, was gathered from the articles, books and monographs published in the past 20 years.

RESULTS

Based on an objective introduction to the CHM toxicity, we clarified the general misconceptions about the safety of CHM and summarized the traditional experiences in dealing with the toxicity. Several PCHM-derived compounds, namely gambogic acid, triptolide, arsenic trioxide, and cantharidin, were selected as representatives, and their traditional usage and mechanism of anti-cancer actions were discussed.

CONCLUSIONS

Natural products derived from PCHM are of extreme importance in devising new drugs and providing unique ideas for the war against cancer. To fully exploit the potential of PCHM in cancer therapy, more attentions are advocated to be focused on their safety evaluation and mechanism exploration.

Chemical characteristics of saponins from Paris fargesii var. brevipetala and cytotoxic activity of its main ingredient, paris saponin H

More attention was paid to the anti-tumor activity of Rhizoma Paridis (RP) recently, of which the wild resource was decreased significantly. This study was aimed to elucidate the chemical characteristics of Paris fargesii var. brevipetala (PFB) that may be administrated as alternate resource of legal RP. A HPLC-ELSD method was established to characterize the steroid saponins in rhizomes of PFB and two legal Paris species [Paris polyphylla var. chinensis (PPC) and P. polyphylla var. yunnanensis (PPY)] in Chinese Pharmacopoeia (CP). Ten saponins (paris saponins I, II, V, VI, VII, H, gracillin and other three paris saponins) were involved as standards. The results indicated that PFB contained pennogenyl saponins as the main components with small amounts of diosgenin saponins. The total contents of the detected saponins in PFB ranged from 9.12mg/g to 85.33mg/g. Nine of the twelve PFB samples own a total content of paris saponins I, II, VI, and VII more than 6.0mg/g (meeting the standard of CP 2010 edition). Principal Component Analysis (PCA) and Partial Least Squares-Discriminate Analysis (PLS-DA) both confirmed the fact that saponin profiles of PFB, PPC and PPY were different from each other. In addition, paris saponin H (Ps H), the predominant saponin of PFB (>50%), was tested in vitro to evaluate its cytotoxic activities on HepG2, A549, RPE and L929 cells with a positive control of Cisplatin. Ps H showed a remarkable cytotoxic activity on A549 cells with an IC(50) value of 1.53±0.08μg/mL.

Adaptive response to oxidative stress: Bacteria, fungi, plants and animals

Reactive oxygen species (ROS) are continuously produced and eliminated by living organisms normally maintaining ROS at certain steady-state levels. Under some circumstances, the balance between ROS generation and elimination is disturbed leading to enhanced ROS level called "oxidative stress". The primary goal of this review is to characterize two principal mechanisms of protection against oxidative stress - regulation of membrane permeability and antioxidant potential. The ancillary goals of this work are to describe up to date knowledge on the regulation of the previously mentioned mechanisms and to identify areas of prospective research and emerging directions in investigation of adaptation to oxidative stress. The ubiquity for challenges leading to oxidative stress development calls for identification of common mechanisms. They are cysteine residues and [Fe,S]-clusters of specific regulatory proteins. The latter mechanism is realized via SoxR bacterial protein, whereas the former mechanism is involved in operation of bacterial OxyR regulon, yeast H(2)O(2)-stimulon, plant NPR1/TGA and Rap2.4a systems, and animal Keap1/Nrf2, NF-κB and AP-1, and others. Although hundreds of studies have been carried out in the field with different taxa, the comparative analysis of adaptive response is quite incomplete and therefore, this work aims to cover a plethora of phylogenetic groups to delineate common mechanisms. In addition, this article raises some questions to be elucidated and points out future directions of this research. The comparative approach is used to shed light on fundamental principles and mechanisms of regulation of antioxidant systems. The idea is to provide starting points from which we can develop novel tools and hypothesis to facilitate meaningful investigations in the physiology and biochemistry of organismic response to oxidative stress.

Phytochemicals: cancer chemoprevention and suppression of tumor onset and metastasis

Carcinogenesis is a multi-step process which could be prevented by phytochemicals. Phytochemicals from dietary plants and other plant sources such as herbs are becoming increasingly important sources of anticancer drugs or compounds for cancer chemoprevention or adjuvant chemotherapy. Phytochemicals can prevent cancer initiation, promotion, and progression by exerting anti-inflammatory and anti-oxidative stress effects which are mediated by integrated Nrf2, NF-kappaB, and AP-1 signaling pathways. In addition, phytochemicals from herbal medicinal plants and/or some dietary plants developed in recent years have been shown to induce apoptosis in cancer cells and inhibition of tumor growth in vivo. In advanced tumors, a series of changes involving critical signaling molecules that would drive tumor cells undergoing epithelial-mesenchymal transition and becoming invasive. In this review, we will discuss the potential molecular targets and signaling pathways that mediate tumor onset and metastasis. In addition, we will shed light on some of the phytochemicals that are capable of targeting these signaling pathways which would make them potentially applicable to cancer chemoprevention, treatment and control of cancer progression.