Circumvention of multi-drug resistance of cancer cells by Chinese herbal medicines

Icaritin Inhibits Migration and Invasion of Human Ovarian Cancer Cells via the Akt/mTOR Signaling Pathway

Ovarian cancer (OC) is the most lethal of all gynecologic malignancies with poor survival rates. Although surgical treatment and chemotherapy had advanced to improve survival, platinum-based chemoresistance remains a major hurdle in the clinical treatment of OC. The search for novel active ingredients for the treatment of drug-resistant OC is urgently needed. Here, we demonstrated that icaritin, the main active ingredient derived from the traditional Chinese herb Epimedium genus, significantly suppressed the proliferation, migration, and invasion of both drug-susceptible and cisplatin-resistant OC cells in vitro. Mechanistically, icaritin at 20 μM significantly inhibited the phosphorylation of Akt and mTOR, as well as decreased the expression of vimentin and increased the expression of E-cadherin. Our data indicate that icaritin, a prenylated flavonoid natural product, could serve as a potential inhibitor of cisplatin-resistant OC by inhibiting the Akt/mTOR signaling pathway.

Glycyrrhizin as a Nitric Oxide Regulator in Cancer Chemotherapy

Simple Summary

Glycyrrhizin (GL) has anti-cancer, anti-inflammatory, anti-viral, and anti-oxidant activity. In particular, GL reduces multidrug resistance (MDR) in cancer cells, which is a major obstacle to chemotherapy. Nitric oxide (NO) also plays an important role in MDR, and GL affects NO concentration in the tumor microenvironment. However, the effects of GL and NO interaction on MDR have not been reviewed. Here, we review the role of GL as an NO regulator in cancer cells and its subsequent anti-MDR effect and posit that GL is a promising MDR inhibitor for cancer chemotherapy.

Abstract

Chemotherapy is used widely for cancer treatment; however, the evolution of multidrug resistance (MDR) in many patients limits the therapeutic benefits of chemotherapy. It is important to overcome MDR for enhanced chemotherapy. ATP-dependent efflux of drugs out of cells is the main mechanism of MDR. Recent studies have suggested that nitric oxide (NO) can be used to overcome MDR by inhibiting the ATPase function of ATP-dependent pumps. Several attempts have been made to deliver NO to the tumor microenvironment (TME), however there are limitations in delivery. Glycyrrhizin (GL), an active compound of licorice, has been reported to both reduce the MDR effect by inhibiting ATP-dependent pumps and function as a regulator of NO production in the TME. In this review, we describe the potential role of GL as an NO regulator and MDR inhibitor that efficiently reduces the MDR effect in cancer chemotherapy.

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet-Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

We present a systematic investigation on an improved variant of the N-acyl-Pictet-Spengler condensation for the synthesis of 1-benzyltetrahydroisoquinolines, based on our recently published synthesis of N-methylcoclaurine, exemplified by the total syntheses of 10 alkaloids in racemic form. Major advantages are a) using ω-methoxystyrenes as convenient alternatives to arylacetaldehydes, and b) using the ethoxycarbonyl residue for both activating the arylethylamine precursors for the cyclization reaction, and, as a significant extension, also as protective group for phenolic residues. After ring closure, the ethoxycarbonyl-protected phenols are deprotected simultaneously with the further processing of the carbamate group, either following route A (lithium alanate reduction) to give N-methylated phenolic products, or following route B (treatment with excess methyllithium) to give the corresponding alkaloids with free N-H function. This dual use of the ethoxycarbonyl group shortens the synthetic routes to hydroxylated 1-benzyltetrahydroisoquinolines significantly. Not surprisingly, these ten alkaloids did not show noteworthy effects on TPC2 cation channels and the tumor cell line VCR-R CEM, and did not exhibit P-glycoprotein blocking activity. But due to their free phenolic groups they can serve as valuable intermediates for novel derivatives addressing all of these targets, based on previous evidence for structure-activity relationships in this chemotype.

Peimine, an Anti-Inflammatory Compound from Chinese Herbal Extracts, Modulates Muscle-Type Nicotinic Receptors

Fritillaria bulbs are used in Traditional Chinese Medicine to treat several illnesses. Peimine (Pm), an anti-inflammatory compound from Fritillaria, is known to inhibit some voltage-dependent ion channels and muscarinic receptors, but its interaction with ligand-gated ion channels remains unexplored. We have studied if Pm affects nicotinic acetylcholine receptors (nAChRs), since they play broad functional roles, both in the nervous system and non-neuronal tissues. Muscle-type nAChRs were incorporated to Xenopus oocytes and the action of Pm on the membrane currents elicited by ACh (I_AChs) was assessed. Functional studies were combined with virtual docking and molecular dynamics assays. Co-application of ACh and Pm reversibly blocked I_ACh, with an IC₅₀ in the low micromolar range. Pm inhibited nAChR by: (i) open-channel blockade, evidenced by the voltage-dependent inhibition of I_Ach, (ii) enhancement of nAChR desensitization, revealed by both an accelerated I_ACh decay and a decelerated I_ACh deactivation, and (iii) resting-nAChR blockade, deduced from the I_ACh inhibition elicited by Pm when applied before ACh superfusion. In good concordance, virtual docking and molecular dynamics assays demonstrated that Pm binds to different sites at the nAChR, mostly at the transmembrane domain. Thus, Pm from Fritillaria bulbs, considered therapeutic herbs, targets nAChRs with high affinity, which might account for its anti-inflammatory actions.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

Matrine Impairs Platelet Function and Thrombosis and Inhibits ROS Production

Matrine is a naturally occurring alkaloid and possesses a wide range of pharmacological properties, such as anti-cancer, anti-oxidant, anti-inflammatory effects. However, whether it affects platelet function and thrombosis remains unclear. This study aims to evaluate the effect of matrine on platelet function and thrombus formation. Human platelets were treated with matrine (0–1 mg/ml) for 1 h at 37°C followed by measuring platelet aggregation, granule secretion, receptor expression by flow cytometry, spreading and clot retraction. In addition, matrine (10 mg/kg) was injected intraperitoneally into mice to measure tail bleeding time, arterial and venous thrombus formation. Matrine dose-dependently inhibited platelet aggregation and ATP release in response to either collagen-related peptide (Collagen-related peptide, 0.1 μg/ml) or thrombin (0.04 U/mL) stimulation without altering the expression of P-selectin, glycoprotein Ibα, GPVI, or αIIbβ3. In addition, matrine-treated platelets presented significantly decreased spreading on fibrinogen or collagen and clot retraction along with reduced phosphorylation of c-Src. Moreover, matrine administration significantly impaired the in vivo hemostatic function of platelets, arterial and venous thrombus formation. Furthermore, in platelets stimulated with CRP or thrombin, matrine significantly reduced Reactive oxygen species generation, inhibited the phosphorylation level of ERK1/2 (Thr202/Tyr204), p38 (Thr180/Tyr182) and AKT (Thr308/Ser473) as well as increased VASP phosphorylation (Ser239) and intracellular cGMP level. In conclusion, matrine inhibits platelet function, arterial and venous thrombosis, possibly involving inhibition of ROS generation, suggesting that matrine might be used as an antiplatelet agent for treating thrombotic or cardiovascular diseases.

A novel flavonoid from Fissistigma cupreonitens, 5‑hydroxy‑7,8‑dimethoxyflavanone, competitively inhibited the efflux function of human P-glycoprotein and reversed cancer multi-drug resistance

BACKGROUND

P-glycoprotein (P-gp) over-expression plays a vital role in not only systemic drug bioavailability but also cancer multi-drug resistance (MDR). Develop functional inhibitors of P-gp can conquer both problems.

PURPOSE AND STUDY DESIGN

The aim of the present study was to research the P-gp modulating effects and MDR reversing ability of a novel flavonoid from Fissistigma cupreonitens, the underlying inhibitory mechanisms were further elucidated as well.

METHODS

Calcein-AM, rhodamine 123, and doxorubicin were fluorescent substrates for the evaluation of P-gp inhibitory function and detailed drug binding modes. Docking simulation was performed to reveal the in silico molecular bonding. ATPase assay and MDR1 shift assay were adopted to reveal the ATP consumption and conformational change of P-gp. The MDR reversing effects were demonstrated through cytotoxicity, cell cycle, and apoptosis analyses.

RESULTS

5‑hydroxy‑7,8‑dimethoxyflavanone inhibited the efflux of rhodamine 123 and doxorubicin in a competitive manner, and increased the intracellular fluorescence of calcein at a concentration as low as 2.5 μg/ml. 5‑hydroxy‑7,8‑dimethoxyflavanone slightly changed P-gp's conformation and only stimulated ATPase at very high concentration (100 μg/ml). The docking results showed that 5‑hydroxy‑7,8‑dimethoxyflavanone and verapamil exhibited similar binding affinity to P-gp. The MDR reversing effects were prominent in the vincristine group, the reversal folds were 23.01 and 13.03 when combined with 10 μg/ml 5‑hydroxy‑7,8‑dimethoxyflavanone in the P-gp over-expressing cell line (ABCB1/Flp-In™-293) and MDR cancer cell line (KB/VIN), respectively.

CONCLUSION

The present study demonstrated that 5‑hydroxy‑7,8‑dimethoxyflavanone was a novel effective flavonoid in the P-gp efflux inhibition and in vitro cancer MDR reversion.

Relaxant Effect of Urginea maritima on Tracheal Smooth Muscle Mediated by the Effect on Beta-2 Adrenergic, Muscarinic Receptors and Calcium and Potassium Channels

Urginea maritima (U. maritima) showed anti-inflammatory, antioxidant, antibacterial, diuretic, vasodilatation, and wound-healing effects on fungal infections, cardiac disorders, digestive disorders, rheumatoid disease, and respiratory disorders such as bronchitis, bronchial nosocomial infections, and severe cough. To examine the bronchodilatory effect of U. maritima, the relaxant effect of its extract on rat tracheal smooth muscle (TSM) and its possible mechanism was examined in this study. Male Wistar rats' TSM were divided into eight groups (n = 8 in each group). Four of these groups were TSM tissues, contracted with KCl (60 mM) incubated with atropine, glibenclamide, and indomethacin and nonincubated TSM, while the other four groups were TSM tissues contracted with methacholine (10 μM) for 5 min, incubated with propranolol, chlorpheniramine, and diltiazem and nonincubated TSM. Cumulative concentrations of U. maritima extract (12.5, 25, 50, 100, 20, and 400 μg/ml) were then added to organ bath every 5 min. Theophylline (0.2, 0.4, 0.6, and 0.8 mM) as positive control and saline (1 ml) as negative control were also examined in nonincubated tissues. A concentration-dependent relaxant effect of U. maritima on nonincubated TSM contracted with KCl (60 mM) or methacholine (10 μM) (p < 0.01 and p < 0.001) was observed. The relaxant effects of U. maritima extract in the incubated tissues with glibenclamide, propranolol, diltiazem, atropine, and chlorpheniramine were significantly lower than those in the nonincubated tissues (p < 0.05 to p < 0.001). EC₅₀ values of U. maritima extract in the incubated TSM with glibenclamide, propranolol, diltiazem, and atropine were significantly higher than those in the nonincubated tissues (p < 0.05 for diltiazem-incubated tissues and p < 0.001 for other cases). U. maritima extract displayed considerable relaxant effect on TSM comparable to the effect of theophylline. Beta-2 adrenoceptor stimulation and muscarinic receptor inhibition as well as potassium opening and calcium channels blocking effects are the possible mechanisms for the relaxant effects of the plant.

Study on reversal of ABCB1 mediated multidrug resistance in Colon cancer by acetogenins: An in-silico approach

Multi-Drug Resistance (MDR) exerted by tumor cells is majorly due to the overexpression of ATP Binding cassette transporters such as ABCB1/P-glycoprotein (P-gp). Annonaceous acetogenins (AGEs) exert anticancer activity by strongly inhibiting NADH oxidase of cancer cells. The present in silico study aims at screening a potent MDR inhibitor among acetogenins from the plant Annona muricata. Twenty-four AGEs were selected and screened for their pharmacokinetic properties. An inward facing conformation of P-gp is required for understanding the interaction of AGEs at the drug binding region and hence the human P-gp protein was modeled. The selected compounds were then docked with the ATP binding site and the drug binding site of modeled human P-gp. Annonacin A.1, Annohexocin.1 and Annomuricin E.1 docked better with high MM/GBSA dG binding in the drug binding region as compared with the conventional drugs. These compounds had a better docking score as compared with control inhibitor drugs at the ATP binding region. The complexes were subjected to MD simulation and Annonacin A was stable throughout the simulation period. Therefore, Annonacin A might act as a competitive inhibitor for the chemo drugs for binding at the drug binding region of P-gp. Hence it is capable of decreasing the efflux of chemo drugs out of the cells by P-Glycoprotein/ABCB1/MDR1. With this computational study, it is concluded that this compound might potentially reverse MDR, and hence can be taken forward for validation studies.Communicated by Ramaswamy H. Sarma.

A Systematic Review of the Pharmacology, Toxicology and Pharmacokinetics of Matrine

Matrine (MT) is a naturally occurring alkaloid and an bioactive component of Chinese herbs, such as Sophora flavescens and Radix Sophorae tonkinensis. Emerging evidence suggests that MT possesses anti-cancer, anti-inflammatory, anti-oxidant, antiviral, antimicrobial, anti-fibrotic, anti-allergic, antinociceptive, hepatoprotective, cardioprotective, and neuroprotective properties. These pharmacological properties form the foundation for its application in the treatment of various diseases, such as multiple types of cancers, hepatitis, skin diseases, allergic asthma, diabetic cardiomyopathy, pain, Alzheimer's disease (AD), Parkinson's disease (PD), and central nervous system (CNS) inflammation. However, an increasing number of published studies indicate that MT has serious adverse effects, the most obvious being liver toxicity and neurotoxicity, which are major factors limiting its clinical use. Pharmacokinetic studies have shown that MT has low oral bioavailability and short half-life in vivo. This review summarizes the latest advances in research on the pharmacology, toxicology, and pharmacokinetics of MT, with a focus on its biological properties and mechanism of action. The review provides insight into the future of research on traditional Chinese medicine.

Therapeutic Emergence of Rhein as a Potential Anticancer Drug: A Review of Its Molecular Targets and Anticancer Properties

According to the World Health Organization (WHO), cancer is the second-highest cause of mortality in the world, and it kills nearly 9.6 million people annually. Besides the fatality of the disease, poor prognosis, cost of conventional therapies, and associated side-effects add more burden to patients, post-diagnosis. Therefore, the search for alternatives for the treatment of cancer that are safe, multi-targeted, effective, and cost-effective has compelled us to go back to ancient systems of medicine. Natural herbs and plant formulations are laden with a variety of phytochemicals. One such compound is rhein, which is an anthraquinone derived from the roots of Rheum spp. and Polygonum multiflorum. In ethnomedicine, these plants are used for the treatment of inflammation, osteoarthritis, diabetes, and bacterial and helminthic infections. Increasing evidence suggests that this compound can suppress breast cancer, cervical cancer, colon cancer, lung cancer, ovarian cancer, etc. in both in vitro and in vivo settings. Recent studies have reported that this compound modulates different signaling cascades in cancer cells and can prevent angiogenesis and progression of different types of cancers. The present review highlights the cancer-preventing and therapeutic properties of rhein based on the available literature, which will help to extend further research to establish the chemoprotective and therapeutic roles of rhein compared to other conventional drugs. Future pharmacokinetic and toxicological studies could support this compound as an effective anticancer agent.

A High-Resolution Mass Spectrometry-Based Quantitative Metabolomic Workflow Highlights Defects in 5-Fluorouracil Metabolism in Cancer Cells with Acquired Chemoresistance

Currently, 5-fluorouracil (5-FU)-based combination chemotherapy is the mainstay in the treatment of metastatic colorectal cancer (CRC), which benefits approximately 50% of the patients. However, these tumors inevitably acquire chemoresistance resulting in treatment failure. The molecular mechanisms driving acquired chemotherapeutic drug resistance in CRC is fundamental for the development of novel strategies for circumventing resistance. However, the specific phenomenon that drives the cancer cells to acquire resistance is poorly understood. Understanding the molecular mechanisms that regulate chemoresistance will uncover new avenues for the treatment of CRC. Among the various mechanisms of acquired chemoresistance, defects in the drug metabolism pathways could play a major role. In the case of 5-FU, it gets converted into various active metabolites, which, directly or indirectly, interferes with the replication and transcription of dividing cells causing DNA and RNA damage. In this project, we developed a high-resolution mass spectrometry-based method to effectively extract and quantify levels of the 5-FU metabolites in cell lysates and media of parental and 5-FU resistant LIM1215 CRC cells. The analysis highlighted that the levels of 5-FU metabolites are significantly reduced in 5-FU resistant cells. Specifically, the level of the nucleotide fluorodeoxyuridine monophosphate (FdUMP) is reduced with treatment of 5-FU clarifying the compromised 5-FU metabolism in resistant cells. Corroborating the metabolomic analysis, treatment of the resistant cells with FdUMP, an active metabolite of 5-FU, resulted in effective killing of the resistant cells. Overall, in this study, an effective protocol was developed for comparative quantitation of polar metabolites and nucleotide analogues from the adherent cells efficiently. Furthermore, the utility of FdUMP as an alternative for CRC therapy is highlighted.

Psoralen Suppresses Cisplatin-Mediated Resistance and Induces Apoptosis of Gastric Adenocarcinoma by Disruption of the miR196a-HOXB7-HER2 Axis

Purpose

The present study aimed to investigate the impact of psoralen on miR-196a-5p expression and function, and to reveal the mechanism underlying miR-196a-5p-mediated inhibition and the reversal of cisplatin (DDP) resistance.

Methods

Serum samples were collected from 50 patients with gastric cancer (GC), and the association between miR-196a-5p expression and the response to chemotherapy was assessed. A DDP-resistant GC cell line was also established to determine the effects of miR-196a-5p and psoralen on DDP resistance. MGC803 cells were transfected with miR-196a-5p mimic and inhibitor vectors for the overexpression and downregulation of miR-196a-5p, respectively.

Results

Clinical data analysis showed that the lower expression levels of miR-196a-5p were significantly associated with chemoresistance in patients with GC. Upregulation of miR-196a-5p significantly enhanced the anti-proliferative effect, apoptosis and sensitivity to DDP by regulating the protein expression levels of HOXB7, HER2, Bcl-2 and G₁/S-specific cyclin-D1 (CCND1). Furthermore, psoralen reversed miR-196a-5p-induced DDP resistance and reduced the expression levels of HOXB7, HER2, Bcl-2 and CCND1.

Conclusion

miR-196a-5p may be a novel biomarker of chemotherapeutic success in patients with GC and may also influence the sensitivity of GC cells to DDP. Moreover, psoralen can increase chemotherapeutic sensitivity by upregulating miR-196a-5p and then downregulating HOXB7-HER2 signaling axis.

Shikonin and 4-hydroxytamoxifen synergistically inhibit the proliferation of breast cancer cells through activating apoptosis signaling pathway in vitro and in vivo

Background

Tamoxifen (TAM) is a cell type-specific anti-estrogen and is applied to improve the survival of patients with estrogen receptor positive (ER +) breast cancer. However, long-term TAM use can induce serious drug resistance, leading to breast cancer recurrence and death in patients. Further, it is almost useless among patients with estrogen receptor negative (ER −) breast cancer. Shikonin (SK) is a natural product broadly explored in cancer therapy. Some studies have demonstrated the combined treatment of SK and clinical anticancer drugs including TAM on various tumors. However, the combined effect of SK and 4-hydroxytamoxifen (4-OHT) on ER- breast cancer is not known. The current study aimed to assess the combination effects of SK and 4-OHT on human breast cancer cells, MCF-7 (ER +) and MDA-MB-435S (ER −), in vitro and in vivo and to investigate the underlying mechanisms.

Methods

CCK-8 assays and flow cytometry were conducted to determine the cell viability and apoptotic profiles of human breast cancer cell lines (MCF-7 and MDA-MB-435S) treated with SK, 4-OHT, and the combination. ROS and JC-1 assays were used to determine ROS level and mitochondrial membrane potential. Western blot analysis was performed to investigate proteins that are associated with apoptosis. Haematoxylin & Eosin (HE) staining was used to detect the tumor and kidney morphology of mice. TUNEL and immunohistochemical staining were performed to detect Ki67 expression level and cell apoptotic profile in tumor tissues.

Results

SK and 4-OHT synergistically inhibited MCF-7 and MDA-MB-435S cell proliferation and promoted apoptosis by reducing mitochondrial membrane potential and increasing the intracellular ROS level. The combination of SK and 4-OHT activated the mitochondrial-dependent apoptosis and the death receptor pathways, significantly regulating the PI3K/AKT/Caspase 9 signaling pathway. Compared with SK and 4-OHT alone, the combination of SK and 4-OHT could better inhibit tumor growth in mice.

Conclusion

The combination of SK and 4-OHT shows highly efficient anticancer effects on breast cancer therapy. SK may be a promising candidate as an adjuvant to 4-OHT for breast cancer treatments, especially for ER- breast cancer.

Rapid Differentiation of Asian and American Ginseng by Differential Ion Mobility Spectrometry-Tandem Mass Spectrometry Using Stepwise Modulation of Gas Modifier Concentration

This study reports a rapid and robust method for the differentiation of Asian and American ginseng samples based on differential ion mobility spectrometry-tandem mass spectrometry (DMS-MS/MS). Groups of bioactive ginsenoside/pseudo-ginsenoside isomers, including Rf/Rg₁/F₁₁, Rb₂/Rb₃/Rc, and Rd/Re, in the ginseng extracts were sequentially separated using DMS with stepwise changes in the gas modifier concentration prior to MS analysis. The identities of the spatially separated ginsenoside/pseudo-ginsenoside isomers were confirmed by their characteristic compensation voltages at specific modifier loading and MS/MS product ions. As expected, Asian ginseng samples contained some Rf and an insignificant amount of F₁₁, whereas American ginseng samples had a high level of F₁₁ but no Rf. The origin of the whole and sliced ginseng could further be confirmed using the quantitative ratios of three sets of ginsenoside markers, namely, Rg₁/Re, Rb₁/Rg₁, and Rb₂/Rc. Based on our results, new benchmark ratios of Rg₁/Re < 0.15, Rb₁/Rg₁ > 2.15, and Rb₂/Rc < 0.26 were proposed for American ginseng (as opposed to Asian ginseng).

The modulation study of multiple drug resistance in bladder cancer by curcumin and resveratrol

Gemcitabine (GCB), which functions via the inhibition of DNA synthesis, is commonly used in the treatment of bladder cancer; however, its response rate is not satisfactory due to the development of drug resistance. The potential for phytochemicals to reverse drug resistance in bladder cancer tumor cells was evaluated. A human bladder cancer cell line, T24, was cultured, and GCB-resistant cells (T24-GCB) were also established. The acquired resistance of T24-GCB to GCB was measured using an MTT assay. The gene expression of ATP-binding cassette (ABC) transporter protein family members was analyzed using reverse transcription-quantitative PCR analysis, and western blotting was performed to verify ABC family protein, cytoplasmic thymidine kinase (TK) and poly (ADP-ribose) polymerase (PARP) expression on whole cell lysates. Subsequently, resveratrol and curcumin were used to evaluate their modulation potential in decreasing the drug resistance of T24-GCB cells to GCB using MTT and migration assays. T24-GCB cells have increased drug resistance ability, with an 18.75-fold higher ID₅₀ value compared with native T24 cells (105 vs. 5.6 nM). T24-GCB cells also exhibit increased cross resistance to mitomycin C and paclitaxel. The mRNA expression of ABCC2 in T24-GCB cells increased compared with that in native T24 cells. Via western blot analysis, it was determined that the expression of ABCC2 protein was also increased in T24-GCB cells. Conversely, the expression of ABCB1, ABCG2, deoxycytidine kinase (DCK), TK1 and TK2 decreased. Following curcumin and resveratrol treatment alone or combined with GCB, additive cytotoxic enhancement was observed, and the migratory abilities of T24-GCB cells were significantly decreased. Western blot analysis revealed that ABCC2 protein expression increased, and DCK, TK1 and TK2 expression decreased following co-treatment of T24-GCB cells with GCB + curcumin or resveratrol compared with GCB alone. Of note, there was a marked increase in cleaved-PARP expression in T24-GCB cells treated with a combination of GCB + curcumin or resveratrol. Both curcumin and resveratrol could reverse the drug resistance of T24-GCB cells in an additive pattern though PARP enhancement without changes in ABCC2 and DCK, TK1 and TK2 expression.

Natural products as multidrug resistance modulators in cancer

Cancer is a prominent cause of death globally. Currently, many drugs that are in clinical practice are having a high prevalence of side effect and multidrug resistance. Risk of tumors acquiring resistance to chemotherapy (multidrug resistance) remains a significant hurdle to the successful treatment of various types of cancer. Membrane-embedded drug transporters, generally overexpressed in cancer, are the leading cause among multiple mechanisms of multidrug resistance (MDR). P-glycoprotein (P-gp) also MDR1/ABCB1, multidrug resistance associated protein 1 (MRP1/ABCC1), MRP2 and breast cancer resistance protein (BCRP/ABCG2) are considered to be a prime factor for induction of MDR. To date, several chemical substances have been tested in a number of clinical trials for their MDR modulatory activity which are not having devoid of any side effects that necessitates to find newer and safer way to tackle the current problem of multidrug resistance in cancer. The present study systematically discusses the various classes of natural products i.e flavonoids, alkaloids, terpenoids, coumarins (from plants, marine, and microorganisms) as potential MDR modulators and/or as a source of promising lead compounds. Recently a bisbenzyl isoquinoline alkaloid namely tetrandrine, isolated from Chinese herb Stephania tetrandra (Han-Fang-Chi) is in clinical trials for its MDR reversal activity.

Oxymatrine‑mediated maturation of dendritic cells leads to activation of FOXP3+/CD4+ Treg cells and reversal of cisplatin‑resistance in lung cancer cells

The dendritic cell (DC)‑regulatory T (Treg) system serves a leading role in the immunosuppression of the tumor microenvironment, which is not conducive to radiotherapy and chemotherapy treatment for lung cancer. The present study aimed to investigate the effect of oxymatrine (OMT) on the DC‑Treg system in the tumor microenvironment in vitro and to examine its mechanism. The expressions of CD83 antigen, T‑lymphocyte activation antigen CD86, CD11 antigen‑like family member C and major histocompatibility complex II in DCs were increased upon treatment with 1 mg/ml OMT, as detected by flow cytometry. Following pretreatment with OMT, the DCs mediated the forkhead box protein P3 overexpression in primitive cluster of differentiation 4+ T cells at the protein and mRNA expression levels. The expression levels of anti‑inflammatory factors, including interleukin (IL)‑10, tumor growth factor‑β, IL‑35, and pro‑inflammatory cytokines, including interferon‑γ, IL‑12 and IL‑2, in the co‑culture supernatant were increased as measured by ELISA. When DCs and DC‑Tregs were co‑cultured with cisplatin‑resistant A549 cells, the proportion of apoptosis in the co‑culture groups was increased under treatment with cisplatin, which was detected by Annexin V/propidium Iodide staining and western blotting. The present results suggested that OMT may promote the maturation of DCs, mediate the differentiation of T cells into Treg cells, and reverse the resistance of tumor cells to cisplatin in vitro. It was suggested that OMT is an important adjunct to chemotherapy through the regulation of antitumor responses.

Chemoprevention of Colorectal Cancer by Dietary Compounds

Colorectal cancer is one of the leading causes of death, and the third most diagnosed type of cancer, worldwide. It is most common amongst men and women over 50 years old. Risk factors include smoking, alcohol, diet, physical inactivity, genetics, alterations in gut microbiota, and associated pathologies (diabetes, obesity, chronic inflammatory bowel diseases). This review will discuss, in detail, the chemopreventive properties of some dietary compounds (phenolic compounds, carotenoids, iridoids, nitrogen compounds, organosulfur compounds, phytosterols, essential oil compounds, polyunsaturated fatty acids and dietary fiber) against colorectal cancer. We present recent data, focusing on in vitro, laboratory animals and clinical trials with the previously mentioned compounds. The chemopreventive properties of the dietary compounds involve multiple molecular and biochemical mechanisms of action, such as inhibition of cell growth, inhibition of tumor initiation, inhibition of adhesion, migration and angiogenesis, apoptosis, interaction with gut microbiota, regulation of cellular signal transduction pathways and xenobiotic metabolizing enzymes, etc. Moreover, this review will also focus on the natural dietary compounds' bioavailability, their synergistic protective effect, as well as the association with conventional therapy. Dietary natural compounds play a major role in colorectal chemoprevention and continuous research in this field is needed.

A preliminary review of studies on adaptogens: comparison of their bioactivity in TCM with that of ginseng-like herbs used worldwide

Modern studies have shown that adaptogens can non-specifically enhance the resistance of human body under a wide range of external stress conditions with a multi-targeted and multi-channel network-like manner, especially by affect the immune-neuro-endocrine system and the hypothalamic–pituitary–adrenal axis. This review article draws the attention to the relationships of adaptogens, tonics from traditional Chinese medicine (TCM) and ginseng-like herbs worldwide, which all have similar plant sources and clinical applications. To clarify the sources and pharmacological mechanisms of these plant-originated adaptogens, which will provide useful information for the utilization of adaptogens to improve the human health. Meanwhile, the TCMs and the world-wide ginseng-like herbs from each region’s ethnopharmacology will be beneficial modernization and globalization.

Overcoming P-Glycoprotein-Mediated Multidrug Resistance in Colorectal Cancer: Potential Reversal Agents among Herbal Medicines

OBJECTIVES

Multidrug resistance (MDR) is the major reason for the failure of chemotherapy in colorectal cancer (CRC), and the primary determinant of MDR in CRC patients is active drug efflux owing to overexpression of P-glycoprotein (P-gp) in cancer tissues. Despite research efforts to overcome P-gp-mediated drug efflux, the high toxicity of P-gp inhibitors has been a major obstacle for the clinical use of these agents. The aim of this study was to review the literature for potential P-gp reversal agents among traditional herbal medicines, which offer the advantages of safety and potential synergetic effects in CRC chemotherapy.

METHODS

We searched ten databases including 3 English databases, 1 Chinese medical database, and 6 Korean medical databases up to July 2018 and included in vivo and in vitro studies evaluating the effects of herbal medicines as P-gp reversal agents in CRC.

RESULTS

A total of 28 potentially related studies were identified and 16 articles were included. Involving 3 studies about Salvia miltiorrhiza and 2 studies about Curcuma longa, finally we found 14 kinds of traditional herbal medicines-Salvia miltiorrhiza, Curcuma longa, Sinomenium acutum, Stephania tetrandra, Bufo gargarizans, Coptis japonica, Piper nigrum and Piper longum, Hedyotis diffusa, Schisandra chinensis, Glycyrrhiza glabra, Glycyrrhiza inflate, Daphne genkwa, Stemona tuberosa Lour, and Andrographis paniculata-as showing efficacy as P-gp inhibitors in anticancer drug-resistant CRC cells in vitro and in vivo.

CONCLUSIONS

This brief account provides insight into the relationship between P-gp and CRC. Further studies on herbal medicines with demonstrated effects against P-gp overexpression will aid in improving the efficacy of chemotherapy in CRC.

Bufalin reverses ABCB1-mediated drug resistance in colorectal cancer

Multidrug resistance (MDR), mainly mediated by ABCB1 transporter, is a major cause for chemotherapy failure. Bufalin (BU), an active component of the traditional Chinese medicine chan’su, has been reported to have antitumor effects on various types of cancer cells. The purpose of this present study was to investigate the reversal effect of BU on ABCB1-mediated multidrug resistance in colorectal cancer. BU at safe concentration (5, 10, 20 nM) could reverse chemosensitivity of ABCB1-overexpression HCT8/ADR, LoVo/ADR and HCT8/ABCB1 nearly back to their parental cells level. In addition, results from the drug accumulation studies revealed that BU was able to enhance intracellular accumulation of doxorubicin (DOX) and Rhodamine 123 (Rho-123) in a dose-dependent manner. Furthermore, Western blot assays showed that BU significantly inhibited the expression level of ABCB1 protein. Meanwhile, BU stimulated the ATPase activity of ABCB1, which suggested that BU might be a substrate of ABCB1. More interestingly, docking analysis predicted that BU could be docked into the large hydrophobic drug-binding cavity of human ABCB1. Importantly, BU remarkable increased the effect of DOX against the ABCB1 resistant HCT8/ADR colorectal cell xenografts in nude mice, without inducing any obvious toxicity. Overall, we concluded that BU efficiently reversed ABCB1-mediated MDR through not only inhibited the efflux function of ABCB1, but also down-regulate its protein expression, which might represent a potential and superior ABCB1 modulator in colorectal cancer.

Role of Non Receptor Tyrosine Kinases in Hematological Malignances and its Targeting by Natural Products

Tyrosine kinases belong to a family of enzymes that mediate the movement of the phosphate group to tyrosine residues of target protein, thus transmitting signals from the cell surface to cytoplasmic proteins and the nucleus to regulate physiological processes. Non-receptor tyrosine kinases (NRTK) are a sub-group of tyrosine kinases, which can relay intracellular signals originating from extracellular receptor. NRTKs can regulate a huge array of cellular functions such as cell survival, division/propagation and adhesion, gene expression, immune response, etc. NRTKs exhibit considerable variability in their structural make up, having a shared kinase domain and commonly possessing many other domains such as SH2, SH3 which are protein-protein interacting domains. Recent studies show that NRTKs are mutated in several hematological malignancies, including lymphomas, leukemias and myelomas, leading to aberrant activation. It can be due to point mutations which are intragenic changes or by fusion of genes leading to chromosome translocation. Mutations that lead to constitutive kinase activity result in the formation of oncogenes, such as Abl, Fes, Src, etc. Therefore, specific kinase inhibitors have been sought after to target mutated kinases. A number of compounds have since been discovered, which have shown to inhibit the activity of NRTKs, which are remarkably well tolerated. This review covers the role of various NRTKs in the development of hematological cancers, including their deregulation, genetic alterations, aberrant activation and associated mutations. In addition, it also looks at the recent advances in the development of novel natural compounds that can target NRTKs and perhaps in combination with other forms of therapy can show great promise for the treatment of hematological malignancies.

Ethanolic extract of Brucea javanica inhibit proliferation of HCT-116 colon cancer cells via caspase activation

Brucea javanica (L.) Merr. is a well-known plant in Chinese System of Medicine. Its fruits and seeds have been reported to possess curative properties against various ailments. The chemical constituents and biological activity of this plant have been an interesting area in plant and chemistry medicine. The aim of this study is to evaluate the antiproliferative effects of the B. javanica extract against a colon cancer cell line and identification of the chemical components derived from the extract. An ethanolic extract from B. javanica fruits was prepared by cold maceration method, subjected to LC-MS profiling to elucidate the composition abbreviated as BJEE. The extract was screened for the cytotoxicity effects on HCT-116 colon cancer cells via MTT and LDH methods. Additionally, AO/PI staining verified apoptosis features in HCT-116 cells through microscopic analysis. ROS, caspase activity, and gene expression has been performed to identify its possible mechanism of actions which contribute to apoptosis. Output data from this study showed BJEE inhibited the cell proliferation of HCT-116 colon cancer cells at IC50 value of 8.9 ± 1.32 (μg mL-1) and significantly increased the levels of caspase-8, 9, and 3/7 in treated cells in comparison to untreated. The changes in expression of caspase genes and some apoptosis genes like Bax and Bcl-2 were confirmed using RT-PCR. Phytochemical analysis by LC-MS identified six major active compounds (bruceine D, isobrucein A, quassimarin, C16 sphinganine, phytosphingosine, and enigmol) in BJEE that may play a key role in cell apoptosis. The current study showed BJEE could be a promising agent for colorectal cancer therapy by significant increase in caspase activity level, and up-regulation of the specific apoptotic genes.

Natural alkaloids as P-gp inhibitors for multidrug resistance reversal in cancer

The biggest challenge associated with cancer chemotherapy is the development of cross multi-drug resistance to almost all anti-cancer agents upon chronic treatment. The major contributing factor for this resistance is efflux of the drugs by the p-glycoprotein pump. Over the years, inhibitors of this pump have been discovered to administer them in combination with chemotherapeutic agents. The clinical failure of first and second generation P-gp inhibitors (such as verapamil and cyclosporine analogs) has led to the discovery of third generation potent P-gp inhibitors (tariquidar, zosuquidar, laniquidar). Most of these inhibitors are nitrogenous compounds and recently a natural alkaloid CBT-01^® (tetrandrine) has advanced to the clinical phase. CBT-01 demonstrated positive results in Phase-I study in combination with paclitaxel, which warranted conducting it's Phase II/III trial. Apart from this, there exist a large number of natural alkaloids possessing potent inhibition of P-gp efflux pump and other related pumps responsible for the development of resistance. Despite the extensive contribution of alkaloids in this area, has never been reviewed. The present review provides a comprehensive account on natural alkaloids possessing P-gp inhibition activity and their potential for multidrug resistance reversal in cancer.

Selection and optimization of nano-formulation of P-glycoprotein inhibitor for reversal of doxorubicin resistance in COLO205 cells

OBJECTIVE

The prime objective of current work was to develop a strategy for preparation of combinational nano-formulation for reversal of drug resistance.

METHODS

As a model system, doxorubicin (DOX)-resistant COLO205 cells were developed and validated. From co-treatment studies with DOX, curcumin was selected as it reversed DOX-resistance at lowest concentration. In an attempt to increase its solubility, curcumin was encapsulated into hydroxypropyl-β-cyclodextrin (HP-β-CD). Here, we propose that presence of stabilizer overcomes its low encapsulation efficiency. Thus, we evaluated curcumin encapsulation in HP-β-CD in presence of different stabilizers and organic solvents. Finally, the effect of nanocurcumin with liposomal DOX was studied for reversal of resistance in COLO205 cells.

KEY FINDINGS

In the process encapsulation, selective optimization of organic solvent by freeze-drying was found to be appropriate among other methods. From optimization studies with different organic solvent (acetone and dichloromethane) and stabilizer [polyvinyl alcohol (PVA) and Pluronics], HP-β-CD-encapsulated curcumin prepared using acetone in PVA-stabilized dispersion increased encapsulation (60%) with size of ~40 nm. Prepared nano-curcumin reversed the DOX resistance effectively in combination with liposomal DOX.

CONCLUSIONS

Curcumin reversed DOX resistance in COLO205 cells at low concentration and enhanced curcumin encapsulation in HP-β-CD was noted in presence of PVA. Further, it was observed that prepared HP-β-CD-encapsulated curcumin is equi-efficacious to nano-dispersed curcumin.

Understanding the Effectiveness of Natural Compound Mixtures in Cancer through Their Molecular Mode of Action

Many approaches to cancer management are often ineffective due to adverse reactions, drug resistance, or inadequate target specificity of single anti-cancer agents. In contrast, a combinatorial approach with the application of two or more anti-cancer agents at their respective effective dosages can achieve a synergistic effect that boosts cytotoxicity to cancer cells. In cancer, aberrant apoptotic pathways allow cells that should be killed to survive with genetic abnormalities, leading to cancer progression. Mutations in apoptotic mechanism arising during the treatment of cancer through cancer progression can consequently lead to chemoresistance. Natural compound mixtures that are believed to have multiple specific targets with minimal acceptable side-effects are now of interest to many researchers due to their cytotoxic and chemosensitizing activities. Synergistic interactions within a drug mixture enhance the search for potential molecular targets in cancer cells. Nonetheless, biased/flawed scientific evidence from natural products can suggest false positive therapeutic benefits during drug screening. In this review, we have taken these factors into consideration when discussing the evidence for these compounds and their synergistic therapeutic benefits in cancer. While there is limited evidence for clinical efficacy for these mixtures, in vitro data suggest that these preparations merit further investigation, both in vitro and in vivo.

Reversal of P-gp-mediated multidrug resistance in colon cancer by cinobufagin

Cinobufagin (CBF) is isolated from the skin and posterior auricular glands of the Asiatic toad (Bufo gargarizans). This study investigated the reversal effect of CBF on P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in colon cancer. The effect of CBF on the cytotoxicity of anticancer drugs in P-gp overexpressing LoVo/ADR, HCT116/L, Cao-2/ADR cells and their parental cells was determined using CCK-8 assay. Apoptosis of anti-cancer drugs and accumulation of doxorubicin (DOX) and Rhodamine 123 (Rho123) in P-gp overexpressing cells were evaluated by flow cytometry. Results indicated that CBF significantly enhanced the sensitivity of P-gp substrate drugs on P-gp overexpressing cells, but had no effect on their parental cells. CBF enhanced the effect of DOX against P-gp-overexpressing LoVo/ADR cell xenografts in nude mice. Moreover, CBF also increased cell apoptosis of chemotherapy agents and intracellular accumulation of DOX and Rho123 in the MDR cells. Further research on the mechanisms revealed non-competitive inhibition of P-gp ATPase activity, but without altering the expression of P-gp. These findings demonstrated that CBF could be further developed into a safe and potent P-gp modulator for combination use with anticancer drugs in cancer chemotherapy.

Involvement of CD147 on multidrug resistance through the regulation of P-glycoprotein expression in K562/ADR leukemic cell line

The relationship between P-gp and CD147 in the regulation of MDR in leukemic cells has not been reported. This study aimed to investigate the correlation between CD147 and P-gp in the regulation of drug resistance in the K562/ADR leukemic cell line. The results showed that drug-resistant K562/ADR cells expressed significantly higher P-gp and CD147 levels than drug-free K562/ADR cells. To determine the regulatory effect of CD147 on P-gp expression, anti-CD147 antibody MEM-M6/6 significantly decreased P-gp and CD147 mRNA and protein levels. This is the first report to show that CD147 mediates MDR in leukemia through the regulation of P-gp expression.

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High expression levels of P-gp and CD147 in drug-resistant cells.

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MEM-M6/6 antibody decreases both CD147 and P-gp expression.

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CD147 mediates MDR phenotype in leukemia through the regulation of P-gp expression.

Psoralen reverses the P-glycoprotein-mediated multidrug resistance in human breast cancer MCF-7/ADR cells

The resistance of cancer to chemotherapeutic agents is a major obstacle during chemotherapy. Clinical multidrug resistance (MDR) is commonly mediated by membrane drug efflux pumps, including ATP‑binding cassette subfamily B member 1, also termed P-glycoprotein (P-gp). P-gp is a membrane transporter encoded by the MDR1 gene. The current study aimed to investigate the impact of psoralen on the expression and function of P‑gp. The 10% inhibitory concentration (IC10) of psoralen, and its capacity to reduce MDR in adriamycin (ADR)‑resistant MCF‑7/ADR cells were determined using MTT assay. The ability of psoralen to modulate the transport activity of P‑gp in MCF‑7/ADR cells was evaluated by measuring the accumulation and efflux of rhodamine 123 (Rh 123) and adriamycin with flow cytometry. The present study evaluated the mRNA level of MDR1 in MCF‑7 and MCF‑7/ADR cells treated with psoralen using reverse transcription-quantitative polymerase chain reaction. The protein expression level of P‑gp was examined by western blot analysis. The current study demonstrated that the IC10 of psoralen in MCF‑7/ADR cells was 8 µg/ml. At 8 µg/ml, psoralen reduced MDR and the sensitivity of the MCF‑7/ADR cells to ADR compared with untreated cells. Additionally, psoralen significantly increased the intracellular accumulation of ADR and Rh 123. However, the IC10 of psoralen did not affect the protein expression levels of P‑gp or mRNA levels of MDR1 (P>0.05). Psoralen reduces MDR by inhibiting the efflux function of P‑gp, which may be important for increasing the efficiency of chemotherapy and improving the clinical protocols aiming to reverse P-gp-mediated MDR.

Wenxia Changfu Formula () induces apoptosis of lung adenocarcinoma in a transplanted tumor model of drug-resistance nude mice

OBJECTIVE

To explore the apoptosis mechanism of Wenxia Changfu Formula (, WCF) in reversing drug resistance of lung cancer in vivo.

METHODS

Thirty model mice were randomly assigned to three groups: control group, cisplatin (CDDP) group, and WCF group. A transplanted tumor model of lung adenocarcinoma was established in all groups. Mice in the WCF group received intragastric administration of WCF (0.2 mL/10 g body weight) everyday in addition to CDDP intraperitoneally (5 mg/kg body weight) twice a week. The mice in the CDDP group received CDDP intraperitoneally (5 mg/kg body weight) twice a week, while the control group received normal saline intraperitoneally (0.2 mL/10 g body weight) everyday. The weight of the nude mice and respective tumors, tumor volume and tumor-inhibiting rate were measured. Electron microscopy was used to observe the existence of apoptosis body. Apoptosis index (AI) was detected by TdT-mediated dUTP nick end labeling staining. The expression of Fas and FasL mRNA was investigated by reverse transcription polymerase chain reaction, while immunohistochemistry was applied to detect the protein expression of Fas and FasL, caspase-3 and caspase-activated DNase (CAD), respectively.

RESULTS

Compared with CDDP group and control group, WCF could significantly reduce the tumor volume from the 19th day and alleviate the tumor weight (P <0.05), and the apoptosis body was found in tumor cells in the WCF group. WCF could also enhance the level of AI, up-regulate the expression of caspase apoptosis pathway related protein caspase-3 and CAD, as well as the expression of Fas, FasL mRNA and protein (P <0.05).

CONCLUSION

WCF could improve the sensitivity of tumor cells to CDDP and reverse the drug resistance by inducing the apoptosis.

Resveratrol induces apoptosis in K562 cells via the regulation of mitochondrial signaling pathways

Resveratrol, an edible polyphenolic phytoalexin obtained primarily from root extracts of the oriental plant, Polygonum cuspidatum and from grapes and red wine, has been reported as an anticancer compound against several types of cancer, the accurate molecular mechanisms of by which it induces apoptosis are limited. In the present study, the molecular mechanisms of resveratrol on human leukemia K562 cells apoptosis was examined. Our results showed that resveratrol significantly decreased cell viability and triggered cell apoptosis in K562 cells. Resveratrol-induced apoptosis of K562 cells was associated with the dissipation of mitochondrial membrane potential (MMP) and the release of cytochrome c into the cytosol. Furthermore, the up-regulation of Bax/Bcl-2 ratio, the activation of caspase-3 and increased cleaved PARP was also observed in K562 cells treated with resveratrol. Thus, we considered that the resveratrol-induced apoptosis of K562 cells might be mediated through the mitochondria pathway, which gives the rationale for in vivo studies on the utilization of resveratrol as a potential cancer therapeutic compound.

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.

Immunomodulatory Protein from Ganoderma microsporum Induces Pro-Death Autophagy through Akt-mTOR-p70S6K Pathway Inhibition in Multidrug Resistant Lung Cancer Cells

Chemoresistance in cancer therapy is an unfavorable prognostic factor in non-small cell lung cancer (NSCLC). Elevation of intracellular calcium level in multidrug resistant (MDR) sublines leads to sensitization of MDR sublines to cell death. We demonstrated that a fungal protein from Ganoderma microsporum, GMI, elevates the intracellular calcium level and reduces the growth of MDR subline via autophagy and apoptosis, regardless of p-glycoprotein (P-gp) overexpression, in mice xenograft tumors. In addition, we examined the roles of autophagy in the death of MDR A549 lung cancer sublines by GMI, thapsigargin (TG) and tunicamycin (TM) in vitro. Cytotoxicity of TG was inhibited by overexpressed P-gp. However, TM-induced death of MDR sublines was independent of P-gp level. Combinations of TG and TM with either docetaxel or vincristine showed no additional cytotoxic effects on MDR sublines. TG- and TM-mediated apoptosis of MDR sublines was demonstrated on Annexin-V assay and Western blot and repressed by pan-caspase inhibitor (Z-VAD-FMK). Treatment of MDR sublines with TG and TM also augmented autophagy with accumulation of LC3-II proteins, breakdown of p62 and formation of acidic vesicular organelles (AVOs). Inhibition of ATG5 by shRNA silencing significantly reduced autophagy and cell death but not apoptosis following TG or TM treatment. GMI treatment inhibited the phosphorylation of Akt/S473 and p70S6K/T389. Interestingly, the phosphorylation of ERK was not associated with GMI-induced autophagy. We conclude that autophagy plays a pro-death role in acquired MDR and upregulation of autophagy by GMI via Akt/mTOR inhibition provides a potential strategy for overcoming MDR in the treatment of lung cancers.

Resveratrol induces apoptosis of leukemia cell line K562 by modulation of sphingosine kinase-1 pathway

To explore the effects of resveratrol in a human myelogenous leukemia cell line K562 and its potential molecular mechanisms. The anti-proliferation effect of resveratrol-induced apoptosis on K562 cells were detected using MTT assay. Western blotting was performed for detecting changes of SphK1 expression in total cell protein and membrane/cytosol protein in K562 cells respectively after exposure to resveratrol. A biochemical assay was used to measure the activity of SphK after treatment of resveratrol, and then S1P and ceramide levels were examined using ELISA kits. Hochest 33258 staining and flow cytometry were applied to detect the apoptosis condition of K562 cells treated with resveratrol. Resveratrol inhibited the proliferation and induced apoptosis in K562 cells in a dose and time-dependent manner. Western blotting revealed that resveratrol did not affect total SphK1 expression level in K562 cells, but significantly changed the translocation of SphK1, the membrane SphK1 was decreased while cytosol SphK1 level was elevated. The activity of SphK1 in resveratrol treated groups was decreased compared to control group with a significant decrease of S1P and increase of ceramide level. Furthermore, Hoechst 33258 staining and Annexin V-FITC analysis confirmed the notable apoptotic effect of resveratrol in its anti-leukemia process. Resveratrol-induced proliferation inhibition of K562 cells might be mediated through its modulation activity of SphK1 pathway by regulating S1P and ceramide levels, which then affected the proliferation and apoptosis process of leukemia cells. SphK1/S1P pathway represents a target of resveratrol in human leukemia.

Modulators of the human ABCC2: hope from natural sources?

Human ABCC2 is an ATP-binding cassette transporter involved in the export of endobiotics and xenobiotics. It is involved in cisplatin resistance in cancer cells, particularly in ovarian cancer. The few known ABCC2 modulators are poorly efficient, so it is necessary to explore new ways to select and optimize efficient compounds ABCC2. Natural products offer an original scaffold for such a strategy and brings hope for this aim. This review covers basic knowledge about ABCC2, from distribution and topology aspects to physiological and pathological functions. It summarizes the effect of natural products as ABCC2 modulators. Certain plant metabolites act on different ABCC2 regulation levels and therefore are promising candidates to block the multidrug resistance mediated by ABCC2 in cancer cells.

Reactive oxygen species (ROS) responsive PEG–PCL nanoparticles with pH-controlled negative-to-positive charge reversal for intracellular delivery of doxorubicin

The charge-conversional behavior and ROS-sensitivity of mPEG-ros-P(CL-co-DCL) NPs for active loading and triggered release of DOX.

Multiple drug resistance due to resistance to stem cells and stem cell treatment progress in cancer (Review)

In recent years, the cancer stem cell (CSC) theory has provided a new angle in the research of cancer, and has gradually gained significance. According to this theory, the multiple drug resistance (MDR) of cancer is most likely due to the resistance of CSCs, and a significant quantity of research has been carried out into the MDR mechanisms of CSC. Over time, some of these mechanisms have been gradually accepted, including ATP-binding cassette transporters, aldehyde dehydrogenase, the CSC microenvironment and epithelial to mesenchymal transition. In the present review, we summarize these mechanisms in detail and review possible appropriate therapy plans against CSCs based on CSC theory.

Antiproliferation and induction of caspase-8-dependent mitochondria-mediated apoptosis by β-tocotrienol in human lung and brain cancer cell lines

The pure vitamin isomer, β-tocotrienol has the least abundance among the other vitamin E isomers that are present in numerous plants. Hence, it is very scarcely studied for its bioactivity. In this study, the antiproliferative effects and primary apoptotic mechanisms of β-tocotrienol on human lung adenocarcinoma A549 and glioblastoma U87MG cells were investigated. It was evidenced that β-tocotrienol had inhibited the growth of both A549 (GI50=1.38±0.334μM) and U87MG (GI50=2.53±0.604μM) cells at rather low concentrations. Cancer cells incubated with β-tocotrienol were also found to exhibit hallmarks of apoptotic morphologies including membrane blebbing, chromatin condensation and formation of apoptotic bodies. The apoptotic properties of β-tocotrienol in both A549 and U87MG cells were the results of its capability to induce significant (P<0.05) double-strand DNA breaks (DSBs) without involving single-strand DNA breaks (SSBs). β-Tocotrienol is said to induce activation of caspase-8 in both A549 and U87MG cells guided by no activation when caspase-8 inhibitor, z-IETD-fmk was added. Besides, disruption on the mitochondrial membrane permeability of the cells in a concentration- and time-dependent manner had occurred. The induction of apoptosis by β-tocotrienol in A549 and U87MG cells was confirmed to involve both the death-receptor mediated and mitochondria-dependent apoptotic pathways. These findings could potentiate the palm oil derived β-tocotrienol to serve as a new anticancer agent for treating human lung and brain cancers.

Anti-tumor activities of matrine and oxymatrine: literature review

Matrine (MT) and oxymatrine (OMT), two kinds of alkaloid components found in the roots of Sophora species, have various pharmacological activities and are demonstrated to have anti-inflammatory, anti-allergic, anti-virus, anti-fibrotic, and cardiovascular protective effects. They are recently proved to have anti-cancer potentials, such as inhibiting cancer cell proliferation, inducing cell cycle arrest, accelerating apoptosis, restraining angiogenesis, inducing cell differentiation, inhibiting cancer metastasis and invasion, reversing multidrug resistance, and preventing or reducing chemotherapy- or radiotherapy-induced toxicity when combined with other chemotherapeutic drugs. In this review, we summarize the recent investigations regarding the anti-cancer activities and possible molecular targets of MT and OMT for cancer prevention and treatment in order to provide clues and references for further study.

P-glycoprotein and its inhibition in tumors by phytochemicals derived from Chinese herbs

P-glycoprotein belongs to the family of ATP-binding cassette (ABC) transporters. It functions in cellular detoxification, pumping a wide range of xenobiotic compounds, including anticancer drugs out of the cell. In cancerous cells, P-glycoprotein confers resistance to a broad spectrum of anticancer agents, a phenomenon termed multidrug resistance. An attractive strategy for overcoming multidrug resistance is to block the transport function of P-glycoprotein and thus increase intracellular concentrations of anticancer drugs to lethal levels. Efforts to identify P-glycoprotein inhibitors have led to numerous candidates, none of which have passed clinical trials with cancer patients due to their high toxicity. The search for naturally inhibitory products from traditional Chinese medicine may be more promising because natural products are frequently less toxic than chemically synthesized substances. In this review, we give an overview of molecular and clinical aspects of P-glycoprotein and multidrug resistance in the context of cancer as well as Chinese herbs and phytochemicals showing inhibitory activity towards P-glycoprotein.

Acalypha wilkesiana extracts induce apoptosis by causing single strand and double strand DNA breaks

ETHNOPHARMACOLOGICAL RELEVANCE

The seeds of Acalypha wilkesiana have been used empirically by traditional healers in Southwest Nigeria together with other plants as a powder mixture to treat patients with breast tumours and inflammation.

AIM OF THE STUDY

There is an increasing interest among researchers in searching for new anticancer drugs from natural resources, particularly plants. This study aimed to investigate the anticancer properties of Acalypha wilkesiana extracts and the characteristics of DNA damage against brain and lung cancer cells.

MATERIALS AND METHODS

The antiproliferative activity of Acalypha wilkesiana extracts (ethyl acetate, hexane, and ethanol) was examined on human glioma (U87MG), human lung carcinoma (A549), and human lung fibroblast (MRC5) cells.

RESULTS

Cell viability MTT assay revealed that ethyl acetate extract of the plant possessed significant antiproliferative effects against both U87MG (GI(50)=28.03 ± 6.44 μg/ml) and A549 (GI(50)=89.63 ± 2.12 μg/ml) cells (p value<0.0001). The hexane extract was found to exhibit crucial antiproliferative effects on U87MG (GI(50)=166.30 ± 30.50 μg/ml) (p value<0.0001) but not on A549 cells. Neither plant extract possessed noticeable antiproliferative effects on the non-cancerous MRC5 cells (GI(50)>300 μg/ml). The ethanol extract showed no antiproliferative effects on any cell line examined. Haematoxylin & Eosin (H & E) staining and single cell gel electrophoresis (SCGE) comet assay confirmed that plant extract-treated cells underwent apoptosis and not necrosis. SCGE comet assays confirmed that plant extracts caused both single strand (SSB) and double strand (DSB) DNA breaks that led to the execution of apoptosis.

CONCLUSION

The extracts (especially ethyl acetate and hexane) of Acalypha wilkesiana possess valuable cytotoxic effects that trigger apoptosis in U87MG and A549 cancer cells through induction of DNA SSBs and DSBs.

Western and Chinese medicine in oncology and hematology

Based on a conclusive theoretical background, both Western and Chinese Medicine have developed diagnostic and therapeutic procedures which lead to reproducible treatment results. Whilst Western Medicine focuses on a most precise diagnosis of tumor histology and the extend of dissemination, Chinese Medicine has developed tools for a functional diagnoses of disturbed body functions. And as Western Medicine aims at producing most specific targeted drugs, Chinese Medicine intends to stabilize disturbed body functions mostly with decoctions. A combined treatment which synergizes specific tumor attack and patient stabilization seems promising. However, the different cultural backgrounds have led to different standards of evaluation. Although the scientific evaluation of Chinese Medicine has led to the development of new drugs, the majority of treatments with decoctions are not evaluated according to the accepted standards. As of today, modern research could only occasionally find explanations for the longstanding experience, but new research ideas have resulted from this confrontation. The approach of combining standard treatments with Chinese treatment concepts only started a few decades ago. The experiences and promising results from smaller studies stand against possible risks of unknown interactions with proven treatment concepts. Pharmacokinetic and clinical studies will be necessary to evaluate these combined treatment concepts. In everyday life, Western and Chinese Medicine should be used in sequence, whereas in studies and special situations the combined approach should be applied to offer possible benefits without causing unnecessary risks to the patients.