Timosaponin A-III reverses multi-drug resistance in human chronic myelogenous leukemia K562/ADM cells via downregulation of MDR1 and MRP1 expression by inhibiting PI3K/Akt signaling pathway

Anti-tumor effect and mechanisms of Timosaponin AIII across diverse cancer progression

Timosaponin AIII (TAIII), a steroidal saponin derived from Anemarrhena asphodeloides Bunge, has gained attention for its versatile therapeutic properties. While well-established for its anti-inflammatory, antidepressant, and anticoagulant properties, emerging research highlights its potent anti-tumor capabilities. This review synthesizes recent findings on the intricate mechanisms and diverse functions of TAIII in cancer therapy, elucidating its impact on various tumor cells, encompassing the effects of TAIII on critical aspects of cancer progression, including metastasis, apoptosis, and autophagy. Additionally, the shared features of TAIII-induced anti-tumor activities, the factors contributing to the multifaceted anti-cancer activities of TAIII, and an exploration of the advantages and disadvantages associated with the regulation of multiple anti-tumor pathways by TAIII are discussed. Furthermore, the detailed regulation of signaling pathways is delineated and tailored to specific cancer types, providing a comprehensive overview of the potential development of TAIII as a promising anti-tumor agent.

Advances in antitumor activity and mechanism of natural steroidal saponins: A review of advances, challenges, and future prospects

BACKGROUND

Cancer, the second leading cause of death worldwide following cardiovascular diseases, presents a formidable challenge in clinical settings due to the extensive toxic side effects associated with primary chemotherapy drugs employed for cancer treatment. Furthermore, the emergence of drug resistance against specific chemotherapeutic agents has further complicated the situation. Consequently, there exists an urgent imperative to investigate novel anticancer drugs. Steroidal saponins, a class of natural compounds, have demonstrated notable antitumor efficacy. Nonetheless, their translation into clinical applications has remained unrealized thus far. In light of this, we conducted a comprehensive systematic review elucidating the antitumor activity, underlying mechanisms, and inherent limitations of steroidal saponins. Additionally, we propose a series of strategic approaches and recommendations to augment the antitumor potential of steroidal saponin compounds, thereby offering prospective insights for their eventual clinical implementation.

PURPOSE

This review summarizes steroidal saponins' antitumor activity, mechanisms, and limitations.

METHODS

The data included in this review are sourced from authoritative databases such as PubMed, Web of Science, ScienceDirect, and others.

RESULTS

A comprehensive summary of over 40 steroidal saponin compounds with proven antitumor activity, including their applicable tumor types and structural characteristics, has been compiled. These steroidal saponins can be primarily classified into five categories: spirostanol, isospirostanol, furostanol, steroidal alkaloids, and cholestanol. The isospirostanol and cholestanol saponins are found to have more potent antitumor activity. The primary antitumor mechanisms of these saponins include tumor cell apoptosis, autophagy induction, inhibition of tumor migration, overcoming drug resistance, and cell cycle arrest. However, steroidal saponins have limitations, such as higher cytotoxicity and lower bioavailability. Furthermore, strategies to address these drawbacks have been proposed.

CONCLUSION

In summary, isospirostanol and cholestanol steroidal saponins demonstrate notable antitumor activity and different structural categories of steroidal saponins exhibit variations in their antitumor signaling pathways. However, the clinical application of steroidal saponins in cancer treatment still faces limitations, and further research and development are necessary to advance their potential in tumor therapy.

Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway

The current study aimed to assess the effect of timosaponin AⅢ (T-AⅢ) on drug-metabolizing enzymes during anticancer therapy. The in vivo experiments were conducted on nude and ICR mice. Following a 24-day administration of T-AⅢ, the nude mice exhibited an induction of CYP2B10, MDR1, and CYP3A11 expression in the liver tissues. In the ICR mice, the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration. The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6, MDR1, and CYP3A4, along with constitutive androstane receptor (CAR) activation. Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression. Furthermore, other CAR target genes also showed a significant increase in the expression. The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice. Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation, with this effect being partially reversed by the ERK activator t-BHQ. Inhibition of the ERK1/2 signaling pathway was also observed in vivo. Additionally, T-AⅢinhibited the phosphorylation of EGFR at Tyr1173 and Tyr845, and suppressed EGF-induced phosphorylation of EGFR, ERK, and CAR. In the nude mice, T-AⅢ also inhibited EGFR phosphorylation. These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.

Natural medicinal compounds target signal transduction pathways to overcome ABC drug efflux transporter-mediated multidrug resistance in cancer

ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 are the major players in drug efflux-mediated multidrug resistance (MDR), which severely affects the efficacy of chemotherapy. Several synthetic compounds block the drug transport by ABC transporters; however, they exhibit a narrow therapeutic window, and produce side effects in non-target normal tissues. Conversely, the downregulation of the expression of ABC drug transporters seems to be a promising strategy to reverse MDR in cancer cells. Several signaling pathways, such as NF-κB, STAT3, Gli, NICD, YAP/TAZ, and Nrf2 upregulate the expression of ABC drug transporters in drug-resistant cancers. Recently, natural medicinal compounds have gained importance to overcome the ABC drug-efflux pump-mediated MDR in cancer. These compounds target transcription factors and the associated signal transduction pathways, thereby downregulating the expression of ABC transporters in drug-resistant cancer cells. Several potent natural compounds have been identified as lead candidates to synergistically enhance chemotherapeutic efficacy, and a few of them are already in clinical trials. Therefore, modulation of signal transduction pathways using natural medicinal compounds for the reversal of ABC drug transporter-mediated MDR in cancer is a novel approach for improving the efficiency of the existing chemotherapeutics. In this review, we discuss the modulatory role of natural medicinal compounds on cellular signaling pathways that regulate the expression of ABC transporters in drug-resistant cancer cells.

The Potential Role of Timosaponin-AIII in Cancer Prevention and Treatment

Cancer, as one of the leading causes of death worldwide, has challenged current chemotherapy drugs. Considering that treatments are expensive, alongside the resistance of tumor cells to anticancer drugs, the development of alternative medicines is necessary. Anemarrhena asphodeloides Bunge, a recognized and well-known medicinal plant for more than two thousand years, has demonstrated its effectiveness against cancer. Timosaponin-AIII (TSAIII), as a bioactive steroid saponin isolated from A. asphodeloides, has shown multiple pharmacological activities and has been developed as an anticancer agent. However, the molecular mechanisms of TSAIII in protecting against cancer development are still unclear. In this review article, we provide a comprehensive discussion on the anticancer effects of TSAIII, including proliferation inhibition, cell cycle arrest, apoptosis induction, autophagy mediation, migration and invasion suppression, anti-angiogenesis, anti-inflammation, and antioxidant effects. The pharmacokinetic profiles of TSAII are also discussed. TSAIII exhibits efficacy against cancer development. However, hydrophobicity and low bioavailability may limit the application of TSAIII. Effective delivery systems, particularly those with tissue/cell-targeted properties, can also significantly improve the anticancer effects of TSAIII.

Potential herb‒drug interactions between anti-COVID-19 drugs and traditional Chinese medicine

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide. Effective treatments against COVID-19 remain urgently in need although vaccination significantly reduces the incidence, hospitalization, and mortality. At present, antiviral drugs including Nirmatrelvir/Ritonavir (PaxlovidTM), Remdesivir, and Molnupiravir have been authorized to treat COVID-19 and become more globally available. On the other hand, traditional Chinese medicine (TCM) has been used for the treatment of epidemic diseases for a long history. Currently, various TCM formulae against COVID-19 such as Qingfei Paidu decoction, Xuanfei Baidu granule, Huashi Baidu granule, Jinhua Qinggan granule, Lianhua Qingwen capsule, and Xuebijing injection have been widely used in clinical practice in China, which may cause potential herb-drug interactions (HDIs) in patients under treatment with antiviral drugs and affect the efficacy and safety of medicines. However, information on potential HDIs between the above anti-COVID-19 drugs and TCM formulae is lacking, and thus this work seeks to summarize and highlight potential HDIs between antiviral drugs and TCM formulae against COVID-19, and especially pharmacokinetic HDIs mediated by metabolizing enzymes and/or transporters. These well-characterized HDIs could provide useful information on clinical concomitant medicine use to maximize clinical outcomes and minimize adverse and toxic effects.

Functional Axis of PDE5/cGMP Mediates Timosaponin-AIII-Elicited Growth Suppression of Glioblastoma U87MG Cells

Glioblastoma (GBM) is the most aggressive brain tumor, with high mortality. Timosaponin AIII (TIA), a steroidal saponin isolated from the medicinal plant Anemarrhena asphodeloides Bge., has been shown to possess anticancer properties in various cancer types. However, the effect of TIA on GBM is unknown. In this study, we reveal that TIA not only inhibited U87MG in vitro cell growth but also in vivo tumor development. Moreover, we found that the cause of TIA-induced cell growth suppression was apoptosis. When seeking to uncover antitumor mechanisms of TIA, we found that TIA diminished the expression of cGMP-specific phosphodiesterase 5(PDE5) while elevating the levels of guanylate cyclases (sGCβ), cellular cGMP, and phosphorylation of VASP^ser239. Following the knockdown of PDE5, PDE5 inhibitor tadalafil and cGMP analog 8-Bro-cGMP both inhibited cell growth and inactivated β-catenin; we reason that TIA elicited an antitumor effect by suppressing PDE5, leading to the activation of the cGMP signaling pathway, which, in turn, impeded β-catenin expression. As β-catenin is key for cell growth and survival in GBM, this study suggests that TIA elicits its anti-tumorigenic effect by interfering with β-catenin function through the activation of a PDE5/cGMP functional axis.

A review of the botany, ethnopharmacology, phytochemistry, pharmacology, toxicology and quality of Anemarrhena asphodeloides Bunge

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizomes of Anemarrhena asphodeloides Bunge., belonging to the family Liliaceae, are named 'Zhi-mu' according to traditional Chinese medicine theory. It is a medicinal plant that has long been used as a tonic agent in various ethnomedicinal systems in East Asia, especially in China, and also for treating arthralgia, hematochezia, tidal fever, night sweats, cough, dry mouth and tongue, hemoptysis, etc. THE ARM OF THE REVIEW: The review aims to provide a systematic overview of botany, ethnopharmacology, phytochemistry, pharmacology, toxicology and quality control of Anemarrhena asphodeloides and to explore the future therapeutic potential and scientific potential of this plant.

MATERIALS AND METHODS

A comprehensive literature search was performed on Anemarrhena asphodeloides using scientific databases including Web of Science, PubMed, Google Scholar, CNKI, Elsevier, SpringerLink, ACS publications, ancient books, Doctoral and master's Theses. Collected data from different sources was comprehensively summarised for botany, ethnopharmacology, phytochemistry, pharmacology, toxicology and quality control of Anemarrhena asphodeloides.

RESULTS

A comprehensive analysis of the literature as mentioned above confirmed that the ethnomedical uses of Anemarrhena asphodeloides had a history of thousands of years in eastern Asian countries. Two hundred sixty-nine compounds have been identified from Anemarrhena asphodeloides, including steroidal saponins, flavonoids, phenylpropanoids, alkaloids, steroids, organic acids, polysaccharides, benzophenones and other ingredients. Studies have shown that the extracts and compounds from Anemarrhena asphodeloides have extensive pharmacological activities, such as nervous system activity, antitumour, anti-inflammatory, antidiabetic, antiosteoporotic, antiallergic, antiplatelet aggregation, antimicrobial, antiviral, anti-ageing, hair growth promoting, preventing cell damage, etc. Evaluating the quality and toxicity of Anemarrhena asphodeloides is essential to confirm its safe use in humans.

CONCLUSION

Anemarrhena asphodeloides is widely used in traditional medicine and have diverse chemical constituents with obvious biological activities. Nevertheless, more studies should be carried out in animals and humans to evaluate the cellular and molecular mechanisms involved in its biological activity and confirm its safe use.

In Vitro Evaluation of the Interaction of Seven Biologically Active Components in Anemarrhenae rhizoma with P-gp

The efficacy and pharmacokinetics of the biologically active components in Anemarrhenae rhizoma (AR) would be affected by the interaction of P-glycoprotein(P-gp) and effective components in AR. However, little is known about the interaction between them. The goal of this research was to examine the transmembrane absorption of timosaponin AIII(TAIII), timosaponin BII(TBII), sarsasapogenin (SSG), mangiferin(MGF), neomangiferin(NMGF), isomangiferin(IMGF), and baohuosideI(BHI) in AR and their interaction with P-gp. Seven effective components in AR(TAIII, TBII, SSG, MGF, NMGF, IMGF, and BHI) were investigated, and MDCK-MDR1 cells were used as the transport cell model. CCK-8 assays, bidirectional transport assays, and Rhodamine-123 (Rh-123) transport assays were determined in the MDCK-MDR1 cells. LC/MS was applied to the quantitative analysis of TAIII, TBII, MGF, NMGF, IMGF, SSG, and BHI in transport samples. The efflux ratio of MGF, TAIII, TBII, and BHI was greater than 2 and significantly descended with the co-administration of Verapamil, indicating MGF, TAIII, TBII, and BHI as the substrates of P-gp. The efflux ratio of the seven effective components in the extracts (10 mg/mL) of AR decreased from 3.00~1.08 to 1.92~0.48. Compared to the efflux ratio of Rh-123 in the control group (2.46), the efflux ratios of Rh-123 were 1.22, 1.27, 1.25, 1.09, 1.31, and 1.47 by the addition of TAIII, TBII, MGF, IMGF, NMGF, and BHI, respectively, while the efflux ratio of Rh-123 with the co-administration of SSG had no statistical difference compared to the control group. These results indicated that MGF, TAIII, TBII, and BHI could be the substrates of P-gp. TAIII, TBII, MGF, IMGF, NMGF, and BHI show the effect of inhibiting P-gp function, respectively. These findings provide important basic pharmacological data to assist the therapeutic development of AR constituents and extracts.

Bile Duct Ligation Impairs Function and Expression of Mrp1 at Rat Blood-Retinal Barrier via Bilirubin-Induced P38 MAPK Pathway Activations

Liver injury is often associated with hepatic retinopathy, resulting from accumulation of retinal toxins due to blood-retinal barrier (BRB) dysfunction. Retinal pigment epithelium highly expresses MRP1/Mrp1. We aimed to investigate whether liver injury affects the function and expression of retinal Mrp1 using bile duct ligation (BDL) rats. Retinal distributions of fluorescein and 2,4-dinitrophenyl-S-glutathione were used for assessing Mrp1 function. BDL significantly increased distributions of the two substrates and bilirubin, downregulated Mrp1 protein, and upregulated phosphorylation of p38 and MK2 in the retina. BDL neither affected the retinal distribution of FITC-dextran nor expressions of ZO-1 and claudin-5, demonstrating intact BRB integrity. In ARPE-19 cells, BDL rat serum or bilirubin decreased MRP1 expression and enhanced p38 and MK2 phosphorylation. Both inhibiting and silencing p38 significantly reversed the bilirubin- and anisomycin-induced decreases in MRP1 protein. Apparent permeability coefficients of fluorescein in the A-to-B direction (Papp, A-to-B) across the ARPE-19 monolayer were greater than Papp, B-to-A. MK571 or bilirubin significantly decreased Papp, A-to-B of fluorescein. Bilirubin treatment significantly downregulated Mrp1 function and expression without affecting integrity of BRB and increased bilirubin levels and phosphorylation of p38 and MK2 in rat retina. In conclusion, BDL downregulates the expression and function of retina Mrp1 by activating the p38 MAPK pathway due to increased bilirubin levels.

Biopharmaceutics and Pharmacokinetics of Timosaponin A-III by a Sensitive HPLC-MS/MS Method: Low Bioavailability Resulting from Poor Permeability and Solubility

BACKGROUND

Timosaponin A-III is one of the most promising active saponins from Anemarrhena asphodeloides Bge. As an oral chemotherapeutic agent, there is an urgent need to clarify its biopharmaceutics and pharmacokinetics to improve its development potential.

OBJECTIVE

This research explores the bioavailability of timosaponin A-III and clarifies its absorption and metabolism mechanisms by a sensitive and specific HPLC-MS/MS method.

METHODS

Pharmacokinetics and bioavailability studies of timosaponin A-III were performed in Sprague- Dawley rats by oral (20 mg/kg) and intravenous administration (2 mg/kg). Control group was given the same volume of normal saline. The absorption of timosaponin A-III was investigated in a rat intestinal perfusion model in situ and a Caco-2 cell transport model in vitro. The metabolic rate of timosaponin A-III was determined in a rat liver microsome incubation system.

RESULTS

After the oral administration, timosaponin A-III reached C_max of 120.90 ± 24.97 ng/mL at 8 h, and the t_1/2 was 9.94 h. The absolute oral bioavailability of timosaponin A-III was 9.18%. The permeability coefficients of timosaponin A-III in four intestinal segments ranged from 4.98 to 5.42 × 10^-7 cm/s, indicating a difficult absorption. A strikingly high efflux transport of timosaponin A-III was found, P_appBA 3.27 ± 0.64 × 10^-6 cm/s, which was abolished by a P-gp inhibitor. Rat liver microsome incubation studies showed that timosaponin A-III could hardly be metabolized, with a t_1/2 of over 12 h. In addition, the solubility test showed a low solubility in PBS solution, i.e. 30.58 μg/mL.

CONCLUSION

Timosaponin A-III exhibited low oral bioavailability by oral and intravenous administration, which was probably caused by its low permeability and solubility. This study may provide a reference for its rational clinical use and further study on the pharmacology or toxicology of timosaponin A-III.

Clinically-Relevant ABC Transporter for Anti-Cancer Drug Resistance

Multiple drug resistance (MDR), referring to the resistance of cancer cells to a broad spectrum of structurally and mechanistically unrelated drugs across membranes, severely impairs the response to chemotherapy and leads to chemotherapy failure. Overexpression of ATP binding cassette (ABC) transporters is a major contributing factor resulting in MDR, which can recognize and mediate the efflux of diverse drugs from cancer cells, thereby decreasing intracellular drug concentration. Therefore, modulators of ABC transporter could be used in combination with standard chemotherapeutic anticancer drugs to augment the therapeutic efficacy. This review summarizes the recent advances of important cancer-related ABC transporters, focusing on their physiological functions, structures, and the development of new compounds as ABC transporter inhibitors.

Timosaponin AIII Induces G2/M Arrest and Apoptosis in Breast Cancer by Activating the ATM/Chk2 and p38 MAPK Signaling Pathways

Timosaponin AIII (TAIII), a steroidal saponin, exerts potent anti-tumor activity in various cancers, especially breast cancer. However, the concrete molecular mechanisms of TAIII against breast cancer are still unclear. Here, we find that TAIII triggers DNA damage, leads to G2/M arrest, and ultimately induces apoptosis in breast cancer both in vitro and in vivo. TAIII induced G2/M phase arrest and apoptosis in MDA-MB-231 and MCF7 cells accompanied with down-regulation of CyclinB1, Cdc2 and Cdc25C. Further data showed that the ATM/Chk2 and p38 pathways were activated representing by up-regulated levels of p-H2A.X and p-p38, which indicated an induction of DNA damage by TAIII, leading to cell cycle arrest and apoptosis. The effects of TAIII were further confirmed by employing inhibitors of ATM and p38 pathways. In vivo, TAIII suppressed the growth of subcutaneous xenograft tumor without obvious toxicity, which indicated by Ki67 and TUNEL analysis. Data also showed that TAIII stimulated the ATM/Chk2 and p38 MAPK pathways in vivo, which in consistent with the effects in vitro. Hence, our data demonstrate that TAIII triggers DNA damage and activates ATM/Chk2 and p38 MAPK pathways, and then induces G2/M phase arrest and apoptosis in breast cancer, which provide theoretical evidence for TAIII utilized as drug against breast cancer.

A Timosaponin B-II containing scalp care solution for improvement of scalp hydration, dandruff reduction, and hair loss prevention: A comparative study on healthy volunteers before and after application

BACKGROUND

The plant species Anemarrhena asphodeloides has commonly been used for health and therapeutic purposes. Timosaponin B-II, which is present at a high concentration in A asphodeloides, was found to enhance the immune and anti-inflammatory responses of human bodies.

AIMS

To evaluate benefits of a timosaponin B-II containing scalp care solution on hair loss prevention and scalp healthiness in multiple physiological and biological profiles.

METHODS

Prior the study, 90 subjects applied scalp care solution base without timosaponin B-II for two weeks followed by application of the scalp care solution containing 0.5% timosaponin B-II for 28 days. The subject's hair follicle hydrocortisone level, hair fall number, hair luster level, dandruff level, sensation score, hydration level, lipid level, redness as well as the pH level of scalps were quantitatively assessed every 7 days.

RESULTS

Multiple parameters on hair and scalp conditions were promoted by application of the timosaponin B-II containing scalp care solution. Compared to baseline values, significant improvements in hair luster, scalp hydration, hair fall number, and scalp redness level could be observed.

CONCLUSION

Timosaponin B-II promotes multiple physiological factors on hair and scalps. The scalp care solution containing A asphodeloides extracts may benefit the scalp healthiness and hair loss prevention.

Konjac glucomannan reverses multi-drug resistance of HepG2/5-FU cells by suppressing AKT signaling and increasing p53 expression

The multi-drug resistance (MDR) of cancer cells, including 5-fluorouracil (5-FU) resistance, has been a serious problem for patients with cancer. The present study aimed to investigate the reversal effects of konjac glucomannan on multi-drug resistance of HepG2/5-FU cells. In the present study, MTT assay was used to investigate the effects of 5-FU and konjac glucomannan (KGM) on the viability of HepG2/5-FU cells. Reverse transcription-quantitative PCR and western blotting were performed to determine the effects of 5-FU and KGM on the expression of MDR-associated genes including MDR1 and P-glycoprotein 1 (P-gp 1), and to analyze the effects of 5-FU and KGM on the levels of cell proliferation-related genes, including cyclin A, cyclin B1 and CDK2, and apoptosis-related genes, including caspase-3, Bax and BCL-2. Annexin V/propidium iodide staining was performed to determine the apoptotic rate of HepG2/5-FU. Furthermore, the xenograft tumor model was established in nude mice to investigate the in vivo tumor growth by detecting tumor size, volume and tumor weight. KGM significantly decreased the viability of HepG2/5-FU cells in the presence of 5-FU. KGM downregulated the mRNA and protein expression of MDR and P-gp, and inhibited the mRNA and protein expression of cyclin A, cyclin B1 and CDK2. In addition, KGM significantly suppressed BCL-2 expression and increased the expression of cleaved caspase-3 and Bax, resulting in a higher apoptotic rate of HepG2/5-FU cells. Furthermore, KGM suppressed AKT phosphorylation and upregulated p53 expression. Notably, KGM significantly inhibited the growth of HepG2/5-FU in nude mice. KGM may be a promising agent against the resistance of HepG2/5-FU cells to 5-FU by suppressing AKT signaling and increasing p53 expression.

Overexpression of ABCB1 and ABCG2 contributes to reduced efficacy of the PI3K/mTOR inhibitor samotolisib (LY3023414) in cancer cell lines

LY3023414 (samotolisib) is a promising new dual inhibitor of phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR). Currently, multiple clinical trials are underway to evaluate the efficacy of LY3023414 in patients with various types of cancer. However, the potential mechanisms underlying acquired resistance to LY3023414 in human cancer cells still remain elusive. In this study, we investigated whether the overexpression of ATP-binding cassette (ABC) drug transporters such as ABCB1 and ABCG2, one of the most common mechanisms for developing multidrug resistance, may potentially reduce the efficacy of LY3023414 in human cancer cells. We demonstrated that the intracellular accumulation of LY3023414 in cancer cells was significantly reduced by the drug efflux function of ABCB1 and ABCG2. Consequently, the cytotoxicity and efficacy of LY3023414 for inhibiting the activation of the PI3K pathway and induction of G0/G1 cell-cycle arrest were substantially reduced in cancer cells overexpressing ABCB1 or ABCG2, which could be restored using tariquidar or Ko143, respectively. Furthermore, stimulatory effect of LY3023414 on the ATPase activity of ABCB1 and ABCG2, as well as in silico molecular docking analysis of LY3023414 binding to the substrate-binding pockets of these transporters provided additional insight into the manner in which LY3023414 interacts with both transporters. In conclusion, we report that LY3023414 is a substrate for ABCB1 and ABCG2 transporters implicating their role in the development of resistance to LY3023414, which can have substantial clinical implications and should be further investigated.

Pharmacological Activity, Pharmacokinetics, and Toxicity of Timosaponin AIII, a Natural Product Isolated From Anemarrhena asphodeloides Bunge: A Review

Anemarrhena asphodeloides Bunge is a famous Chinese Materia Medica and has been used in traditional Chinese medicine for more than two thousand years. Steroidal saponins are important active components isolated from A. asphodeloides Bunge. Among which, the accumulation of numerous experimental studies involved in Timosaponin AIII (Timo AIII) draws our attention in the recent decades. In this review, we searched all the scientific literatures using the key word "timosaponin AIII" in the PubMed database update to March 2020. We comprehensively summarized the pharmacological activity, pharmacokinetics, and toxicity of Timo AIII. We found that Timo AIII presents multiple-pharmacological activities, such as anti-cancer, anti-neuronal disorders, anti-inflammation, anti-coagulant, and so on. And the anti-cancer effect of Timo AIII in various cancers, especially hepatocellular cancer and breast cancer, is supposed as its most potential activity. The anti-inflammatory activity of Timo AIII is also beneficial to many diseases. Moreover, VEGFR, X-linked inhibitor of apoptosis protein (XIAP), B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1), thromboxane (Tx) A2 receptor, mTOR, NF-κB, COX-2, MMPs, acetylcholinesterase (AChE), and so on are identified as the crucial pharmacological targets of Timo AIII. Furthermore, the hepatotoxicity of Timo AIII was most concerned, and the pharmacokinetics and toxicity of Timo AIII need further studies in diverse animal models. In conclusion, Timo AIII is potent as a compound or leading compound for further drug development while still needs in-depth studies.

Antiangiogenesis effect of timosaponin AIII on HUVECs in vitro and zebrafish embryos in vivo

Timosaponin AIII (Timo AIII) is a natural steroidal saponin isolated from the traditional Chinese herb Anemarrhena asphodeloides Bge with proved effectiveness in the treatment of numerous cancers. However, whether Timo AIII suppresses tumor angiogenesis remains unclear. In the present study, we investigated the antiangiogenesis effects of Timo AIII and the underlying mechanisms in human umbilical vein endothelial cells (HUVECs) in vitro and zebrafish embryos in vivo. We showed that treatment with Timo AIII (0.5-2 µM) partially disrupted the intersegmental vessels (ISVs) and subintestinal vessels (SIVs) growth in transgenic zebrafish Tg(fli-1a: EGFP)y1. Timo AIII (0.5-4 µM) dose-dependently inhibited VEGF-induced proliferation, migration, invasion, and tube formation of HUVECs, but these inhibitory effects were not due to its cytotoxicity. We further demonstrated that Timo AIII treatment significantly suppressed the expression of VEGF receptor (VEGFR) and the phosphorylation of Akt, MEK1/2, and ERK1/2 in HUVECs. Timo AIII treatment also significantly inhibited VEGF-triggered phosphorylation of VEGFR2, Akt, and ERK1/2 in HUVECs. Moreover, we conducted RNA-Seq and analyzed the transcriptome changes in both HUVECs and zebrafish embryos following Timo AIII treatment. The coexpression network analysis results showed that various biological processes and signaling pathways were enriched including angiogenesis, cell motility, cell adhesion, protein serine/threonine kinase activity, transmembrane signaling receptor activity, growth factor activity, etc., which was consistent with the antiangiogenesis effects of Timo AIII in HUVECs and zebrafish embryos. We conclude that the antiangiogenesis effect of Timo AIII is mediated through VEGF/PI3K/Akt/MAPK signaling cascade; Timo AIII potentially exerts antiangiogenesis effect in cancer treatment.

Contactin 1 modulates pegylated arginase resistance in small cell lung cancer through induction of epithelial-mesenchymal transition

Drug resistance is a major hurdle in the treatment of small cell lung cancer (SCLC). Previously we demonstrated the potential anticancer effect of pegylated arginase BCT-100 in SCLC cell lines and xenograft models. To facilitate future clinical application of BCT-100 in SCLC treatment, we elucidated the potential mechanisms that underlie acquired drug resistance to BCT-100. H446 and H526 SCLC cells were serially cultured in stepwise increasing concentrations of BCT-100 until stable BCT-100-resistant cell lines emerged (H446-BR and H526-BR). Compared with parent cells, H446-BR and H526-BR displayed stronger migration ability, anoikis resistance and EMT progression. Gene chip assay was employed to select three potential targets (CDH17, CNTN-1 and IGF2BP1). Silencing CNTN-1 rather than CDH17 or IGF2BP1 in H446-BR and H526-BR cells re-sensitized resistant cells to BCT-100 treatment and attenuated the epithelial–mesenchymal transition (EMT) phenotype. The AKT signaling pathway was activated in H446-BR and H526-BR cells accompanied by EMT progression, and AKT inhibitor LY294002 reversed the EMT progression in resistant cells.

Polyphyllin I induces apoptosis and autophagy via modulating JNK and mTOR pathways in human acute myeloid leukemia cells

Polyphyllin I (PPI), a bioactive component extracted from Paris polyphylla, was reported to have potent anticancer activities in previous studies. However, there were few reports on the effects and underlying mechanism of PPI in human acute myeloid leukemia cells. The present study demonstrated that PPI had an inhibitory effect through inducing apoptosis and autophagy in THP-1 and NB4 cells. PPI induced apoptosis via activating JNK pathway, as evidenced by the decreased Bcl-2 levels and increased Bax, cleaved-caspase-3 and phosphorylated-JNK expressions. In addition, PPI promoted autophagy as evidenced with increased expressions of LC3-II and Beclin-1 in western blot and autophagic vacuoles in MDC staining, which was associated with the inhibition of AKT-mTOR pathway. Furthermore, JNK inhibitor SP600125 and autophagy inhibitor 3-MA were employed to evaluate the role of apoptosis and autophagy in PPI-induced cell death. We found that autophagy and apoptosis were both causes of cell death induced by PPI. These data suggested that PPI could be a potent therapeutic agent for the treatment of human acute myeloid leukemia.

Timosaponin AIII, a steroidal saponin, exhibits anti-tumor effect on taxol-resistant cells in vitro and in vivo

Timosaponin AIII (TAIII), a steroidal saponin isolated from the rhizome of Anemarrhena asphodeloides, exerted cytotoxic effect in many cancer cell lines. However, the effect of TAIII on resistant tumor cancer cells was unclear. In this study, MTT assay showed that TAIII exhibited significant cytotoxicity against A549/Taxol and A2780/Taxol cells in vitro. Annexin V-FITC/PI staining revealed that TAIII induced apoptosis in A549/T and A2780/T cells. Furthermore, Western blot analysis demonstrated that TAIII inhibited the expressions of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR) as well as Ras, Raf, mitogen-activated protein kinase (MEPK), extracellular regulated protein kinases (ERK) in two taxol-resistant cancer cell lines. Besides, in vivo studies demonstrated that TAIII inhibited tumor growth in a nude mouse xenograft model. Additionally, TAIII (2.5 and 5 mg/kg) also down-regulated the protein expressions of PI3K/AKT/mTOR and Ras/Raf/MEK/ERK pathways in vivo. Taken together, these findings demonstrated that TAIII exhibited significant anti-tumor effect on taxol-resistant cells.

Identification of Thienopyrimidine Scaffold as an Inhibitor of the ABC Transport Protein ABCC1 (MRP1) and Related Transporters Using a Combined Virtual Screening Approach

A virtual screening protocol with combination of similarity search and pharmacophore modeling was applied to virtually screen a large compound library to gain new scaffolds regarding ABCC1 inhibition. Biological investigation of promising candidates revealed four compounds as ABCC1 inhibitors, three of them with scaffolds not associated with ABCC1 inhibition until now. The best hit molecule-a thienopyrimidine-was a moderately potent, competitive inhibitor of the ABCC1-mediated transport of calcein AM which also sensitized ABCC1-overexpressing cells toward daunorubicin. Further evaluation showed that it was a moderately potent, competitive inhibitor of the ABCB1-mediated transport of calcein AM, and noncompetitive inhibitor of the ABCG2-mediated pheophorbide A transport. In addition, the thienopyrimidine could also sensitize ABCB1- as well as ABCG2-overexpressing cells toward daunorubicin and SN-38, respectively, in concentration ranges that qualified it as one of the ten best triple ABCC1/ABCB1/ABCG2 inhibitors in the literature. Besides, three more new multitarget inhibitors were identified by this virtual screening approach.

Mechanisms of drug resistance in acute myeloid leukemia

Acute myeloid leukemia (AML) is a kind of malignant hematopoietic system disease characterized by abnormal proliferation, poor cell differentiation, and infiltration of bone marrow, peripheral blood, or other tissues. To date, the first-line treatment of AML is still based on daunorubicin and cytosine arabinoside or idarubicin and cytosine arabinoside regimen. However, the complete remission rate of AML is still not optimistic, especially in elderly patients, and the recurrence rate after complete remission is still high. The resistance of leukemia cells to chemotherapy drugs becomes the main obstacle in the treatment of AML. At present, the research on the mechanisms of drug resistance in AML is very active. This article will elaborate on the main mechanisms of drug resistance currently being studied, including drug resistance-related proteins and enzymes, gene alterations, micro RNAs, and signal pathways.

Peptidylarginine deiminase 4 overexpression resensitizes MCF-7/ADR breast cancer cells to adriamycin via GSK3β/p53 activation

Background

Adriamycin (ADR) is widely used in the clinical chemotherapy against breast cancer. But its efficacy is strongly limited due to the acquisition of multidrug resistance (MDR). Therefore, acquisition of the resistance to ADR is still a major cause of chemotherapy failure in breast cancer patients. Peptidylarginine deiminase IV (PAD4) is reported to target non-histone proteins for citrullination, regulate their substrate activities, and thereby play critical roles in maintaining cell phenotype in breast cancer cells. However, whether PAD4 is involved in the development of MDR in breast cancer is poorly understood.

Materials and methods

We examined the expression of PAD family members, including PAD4 in ADR-resistant MCF-7 cells compared with the parental control cells by real-time PCR and Western blotting analyses. Rescue of PAD4 expression in MCF-7/ADR cells was performed to assess whether PAD4 could restore the sensitivity of MCF-7/ADR cells to ADR treatment with cell counting kit-8, flow cytometry, TUNEL, nuclear and cytoplasmic extract preparations, and immunofluorescence staining analyses.

Results

Both PAD2 and PAD4 were significantly decreased in ADR-resistant cells. However, only PAD4 overexpression can increase the sensitivity of MCF-7/ADR cells to ADR treatment and decrease MDR1 gene expression. Overexpression of PAD4 in MCF-7/ADR cells inhibited cell proliferation by inducing cell apoptosis. Under ADR treatment, overexpression of PAD4 promoted nuclear accumulation of glycogen synthase kinase-3β and p53, which further activated proapoptotic gene expression and downregulated MDR1 expression. Moreover, PAD4 activity was required for activating proapoptotic gene transcripts.

Conclusion

We demonstrate the previously unappreciated role of PAD4 in reversing ADR resistance in MCF-7/ADR cells and help establish PAD4 as a candidate biomarker of prognosis and chemotherapy target for MDR in breast cancers.

Timosaponin AIII: A novel potential anti-tumor compound from Anemarrhena asphodeloides

Timosaponin AIII, a major steroidal saponin found in Anemarrhena asphodeloides Bge., which has been widely used as anti-pyretic, anti-diabetic, anti-inflammatory, anti-platelet aggregator and anti-depressant agents in traditional Chinese medicine. Recent pharmacological study showed that timosaponin AIII had potent cytotoxicity, which was potential to be developed as an anticancer agent, however the molecular mechanism underlying the anticancer activity has not been fully elucidated. This review aims to give a systematic summary of the study of timosaponin AIII to reveal its anti-tumor activities by investigating invasion and migration, apoptosis, autophagy and reversing multi-drug resistance. Furthermore, we also make an overview of the mechanisms identified till now. These meaningful findings may provide novel insights on exploiting timosaponin AIII as a new anti-tumor agent.

β-elemene enhances anticancer bone neoplasms efficacy of paclitaxel through regulation of GPR124 in bone neoplasms cells

The purpose of the present study was to investigate the anticancer effects of β-elemene and paclitaxel for bone neoplasms. MTT assay, reverse transcription-quantitative polymerase chain reaction, western blotting, flow cytometry and immunostaining were used to analyze the combined effects of β-elemene and paclitaxel both in vitro and in vivo. The results demonstrated that combined treatment of β-elemene and paclitaxel (β-elemene-paclitaxel) significantly inhibited growth and aggressiveness of U-2OS cells compared with either β-elemene or paclitaxel treatment alone. It was demonstrated that β-elemene promoted paclitaxel-induced apoptosis of U-2OS cells. Anti-apoptosis B-cell lymphoma (Bcl)-2 and Bcl-w genes were downregulated and pro-apoptotic Bcl-2-associated agonist of cell death and caspase-3 genes were upregulated in U-2OS cells following treatment with β-elemene-paclitaxel. Treatment of β-elemene-paclitaxel arrested the cell cycle and decreased cyclin-dependent kinase, cyclin-B1, P21 and P27 expression levels and decreased resistant genes alterations of ATP binding cassette subfamily B member 1, LDL receptor related protein and TS in U-2OS cells. Results demonstrated that β-elemene-paclitaxel decreased G-protein coupled receptor 124 (GPR124), vascular endothelial growth factor receptor, matrix metallopeptidase (MMP)-3, MMP-9 expression levels and increased endostatin, TIMP metallopeptidase inhibitor (TIMP)-1, TIMP-2 expression in U-2OS cells. In vivo assay demonstrated that β-elemene-paclitaxel treatment inhibited tumor growth of BALB/c-nu/nu nude mice and prolonged survival rate of tumor-bearing mice. Immunostaining demonstrated that β-elemene-paclitaxel treatment increased apoptotic bodies, GPR124 and increased endostatin, TIMP-1 and TIMP-2 expression in tumor tissues. In conclusion, these results suggest that the combined treatment of β-elemene-paclitaxel is more effective at inhibiting bone neoplasm growth than β-elemene or paclitaxel single treatment GPR124.

Antiproliferative effect of ZSTK474 alone or in combination with chemotherapeutic drugs on HL60 and HL60/ADR cells

While chemotherapy remains to be one of the main approaches in the clinical treatment of acute myeloid leukemia (AML), multidrug resistance (MDR) has become a serious problem which limits the therapeutic efficacy. The important roles of the PI3K/Akt pathway in modulating cell proliferation and MDR suggest that PI3K inhibitor might be effective for treatment of AML. In the present study, the antiproliferative effects of PI3K inhibitor ZSTK474 on AML cell HL60 and the adriamycin (ADR)-resistant HL60/ADR cells were investigated. Our data indicated that ZSTK474 exhibited potent antiproliferative activity, induced G1 cell cycle arrest, but no obvious apoptosis in both cell lines. Moreover, ZSTK474 affected the protein levels of cell-cycle-related molecules including increased p27, decreased cyclin D1 and phosphorylated Rb in dose-dependent manner. The proteins downstream of PI3K including phosphorylated PDK1, Akt and GSK-3β were reduced in a dose-dependent manner after ZSTK474 treatment. ZSTK474 reversed ADR resistance, increased the intracellular accumulation of ADR, and reduced the expression and function of multidrug resistance (MDR) proteins including both P-gp and MRP1 in HL60/ADR cells. The combination of ZSTK474 and chemotherapeutic drugs cytarabine or vincristine led to a synergistic effect in HL60 and HL60/ADR cells. In conclusion, ZSTK474 showed potent antiproliferative effect on HL60 and HL60/ADR cells; combination with cytarabine or vincristine resulted in synergistic effect. Our results suggest ZSTK474 has the potential to be applied in the treatment of AML patients, while further evidences particularly those about in vivo efficacy are needed.

Germacrone reverses adriamycin resistance in human chronic myelogenous leukemia K562/ADM cells by suppressing MDR1 gene/P-glycoprotein expression

Multidrug resistance (MDR) usually causes chemotherapy failure of chronic myelogenous leukemia (CML). Germacrone is a terpenoid compound and has been reported to reverse MDR in breast cancer cells. However, the effect of germacrone on MDR in CML cells was unknown. The aim of the present study was to evaluate the effect of germacrone on MDR in adriamycin resistance of CML cells. Treatment with a combination of germacrone and adriamycin synergistically inhibited the viability and increased LDH release in K562/ADM cells. Adriamycin induced the apoptosis and caspase-3 activity of K562/ADM cells, and the germacrone treatment significantly enhanced the induction. Adriamycin treatment inhibited the expression of Bcl-2 and induced the expression of Bax, and germacrone enhanced the effect of adriamycin. Germacrone decreased adriamycin-induced expression of MDR1 mRNA and P-gp protein. Overexpression of P-glycoprotein (P-gp) reversed the effect of germacrone on adriamycin resistance in K562/ADM cells. In conclusion, germacrone reversed adriamycin resistance in human chronic myelogenous leukemia K562/ADM cells by suppressing MDR1 gene/P-gp expression. The results indicated that germacrone might be a new MDR reversal agent for CML chemotherapy.

Antibody-modified liposomes for tumor-targeting delivery of timosaponin AIII

Introduction

Timosaponin AIII (TAIII), as a steroid saponin in Anemarrhena asphodeloides, has favorable potential as an antitumor candidate. However, its hydrophobicity and low bioavailability severely limit its in vivo antitumor efficacy.

Methods

To overcome this drawback, TAIII-loaded liposomes (LP) were prepared to improve TAIII solubility and extend its circulation time. Furthermore, anti-CD44 antibody-modified LP (CD44-LP) was prepared to enhance the therapeutic index of TAIII. The LP and CD44-LP were also characterized through their biological activity, target selective binding and uptake, and in vivo pharmacokinetics.

Results

Compared with free TAIII, both LP and CD44-LP possessed a desirable sustained-release profile in vitro, with ~14.2- and 10.7-fold longer TAIII half-life, respectively, and 1.7- and 1.9-fold larger area under the curve, respectively. LP and CD44-LP enhanced TAIII antitumor activity against HepG2 cells and in a xenograft mouse model without detectable toxicity. In particular, CD44-LP exhibited notably higher cytotoxicity than did LP, with a lower half-maximal inhibitory concentration (48 h). CD44-LP exhibited stronger tumor inhibition, and the tumor inhibitory effect was 1.3-fold that of LP. Furthermore, confocal laser scanning microscopy and in vivo near-infrared imaging of a xenograft mouse model revealed that compared with LP, CD44-LP could effectively enhance tumor accumulation.

Conclusion

Taken together, the results indicate that both CD44-LP and LP can considerably extend TAIII circulation time, increase tumor-targeted accumulation, and enhance antitumor activity. Thus, the anti-CD44 antibody-modified liposome is a promising candidate for treating CD44-positive cancer with considerable antitumor effects.

Timosaponin A-III inhibits oncogenic phenotype via regulation of PcG protein BMI1 in breast cancer cells

Polycomb group (PcG) protein BMI1 is an important regulator of oncogenic phenotype and is often overexpressed in several human malignancies including breast cancer. Aberrant expression of BMI1 is associated with metastasis and poor prognosis in cancer patients. At present, therapy reagents that can efficiently inhibit the expression of BMI1 are not very well known. Here, we report that Timosaponin A-III (TA-III), a steroidal saponin obtained from the rhizomes of an herb, Anemarrhena asphodeloides, strongly inhibits expression of BMI1 in breast cancer cells. Treatment of breast cancer cells with TA-III resulted in inhibition of oncogenic phenotypes such as proliferation, migration and invasion, and induction of cellular senescence. Inhibition of these oncogenic phenotypes was accompanied by downregulation of BMI1 expression and histone posttranslational modification activity of PRC1. The mechanistic analysis of TA-III-induced inhibition of oncogenic activity and BMI1 expression suggests that downregulation of c-Myc mediates TA-III effect on BMI1. We further show that exogenous BMI1 overexpression can overcome TA-III-induced inhibition of oncogenic phenotypes. We also show that TA-III induces expression of tumor suppressive miR-200c and miR-141, which are negatively regulated by BMI1. In summary, our data suggest that TA-III is a potent inhibitor of BMI1 and that it can be successfully used to inhibit the growth of tumors where PcG protein BMI1 and PcG activities are upregulated.

ATP-binding cassette transporter A1: A promising therapy target for prostate cancer

ATP-binding cassette transporter A1 (ABCA1) has been found to mediate the transfer of cellular cholesterol across the plasma membrane to apolipoprotein A-I (apoA-I), and is essential for the synthesis of high-density lipoprotein. Mutations of the ABCA1 gene may induce Tangier disease and familial hypoalphalipoproteinemia; they may also lead to loss of cellular cholesterol homeostasis in prostate cancer, and increased intracellular cholesterol levels are frequently found in prostate cancer cells. Recent studies have demonstrated that ABCA1 may exert anticancer effects through cellular cholesterol efflux, which has been attracting increasing attention in association with prostate cancer. The aim of the present review was to focus on the current views on prostate cancer progression and the various functions of ABCA1, in order to provide new therapeutic targets for prostate cancer.

L1 increases adhesion-mediated proliferation and chemoresistance of retinoblastoma

Retinoblastoma is the most common intraocular cancer in children, affecting 1/20,000 live births. Currently, children with retinoblastoma were treated with chemotherapy using drugs such as carboplatin, vincristine, and etoposide. Unfortunately, if conventional treatment fails, the affected eyes should be removed to prevent extension into adjacent tissues and metastasis. This study is to investigate the roles of L1 in adhesion-mediated proliferation and chemoresistance of retinoblastoma. L1 was differentially expressed in 30 retinoblastoma tissues and 2 retinoblastoma cell lines. Furthermore, the proportions of L1-positive cells in retinoblastoma tumors were negatively linked with the number of Flexner-Wintersteiner rosettes, a characteristic of differentiated retinoblastoma tumors, in each tumor sample. Following in vitro experiments using L1-deleted and -overexpressing cells showed that L1 increased adhesion-mediated proliferation of retinoblastoma cells via regulation of cell cycle-associated proteins with modulation of Akt, extracellular signal-regulated kinase, and p38 pathways. In addition, L1 increased resistance against carboplatin, vincristine, and esoposide through up-regulation of apoptosis- and multidrug resistance-related genes. In vivo tumor formation and chemoresistance were also positively linked with the levels of L1 in an orthotopic transplantation model in mice. In this manner, L1 increases adhesion-mediated proliferation and chemoresistance of retinoblastoma. Targeted therapy to L1 might be effective in the treatment of retinoblastoma tumors, especially which rapidly proliferate and demonstrate resistance to conventional chemotherapeutic drugs.

Cepharanthine hydrochloride reverses P‑glycoprotein-mediated multidrug resistance in human ovarian carcinoma A2780/Taxol cells by inhibiting the PI3K/Akt signaling pathway

Ovarian cancer has the highest mortality rate among gynecologic malignant tumors. The major obstacle to treatment success is multidrug resistance (MDR) to chemotherapy drugs. Cepharanthine hydrochloride (CH), a natural alkaloid-derived compound, has shown MDR reversal potency in several tumor cell lines; however, the molecular mechanism is not entirely known. In the present study, we assessed whether CH sensitized malignant cells to chemotherapy drugs in ovarian cancer and explored the relevant mechanism. We found that CH reduced the IC50 value of paclitaxel and increased intracellular rhodamine-123 accumulation in human ovarian cancer A2780/Taxol cells in a concentration-dependent manner. Reverse transcription polymerase chain reaction and western blot assay demonstrated that CH inhibited MDR1 expression as indicated by reduced mRNA and protein levels in A2780/Taxol cells. In addition, the inhibitory effect was strengthened after CH was combined with the specific PI3K/Akt signaling pathway inhibitor LY294002. Furthermore, p‑Akt expression decreased gradually with the concentration of CH (2, 4 and 8 µM). Taken together, these findings indicated that CH reversed P‑glycoprotein-mediated MDR in A2780/Taxol cells by inhibiting the PI3K/Akt signaling pathway.

Dual inhibition of P-glycoprotein and midkine may increase therapeutic effects of anticancer drugs

Multidrug resistance (MDR) to chemotherapy may significantly affect the outcome of cancer treatment. ATP-dependent drug efflux pumps, including P-glycoprotein (P-gp), contribute to the resistance of various chemotherapeutic agents. Overexpression of P-gp in tumor cells induces chemoresistance via pumping the anticancer drugs out of the cells. In addition to taking part in many biological processes such as development, reproduction and repair, midkine (MK) also plays important roles in the pathogenesis of malignant diseases as well as in the regulation of MDR. Although, the mechanisms of action of P-gp and MK are different, overexpression of both proteins prevents the accumulation of many chemotherapeutics in tumor cells, leading to decreased therapeutic effects of anticancer drugs. Therefore, identification of the result of dual inhibition of P-gp and MK in overcoming chemoresistance may enhance the likelihood for a more efficient chemotherapy.

With no interaction, knockdown of Apollon and MDR1 reverse the multidrug resistance of human chronic myelogenous leukemia K562/ADM cells

Chemotherapy is the main treatment method for patients with chronic myeloid leukemia (CML) and has achieved marked results. However, the acquisition of multidrug resistance (MDR) has seriously affected the quality of life and survival rate of patients. The overexpression of the inhibitors of apoptosis proteins (IAPs) and the adenosine triphosphate (ATP)-dependent binding cassette (ABC) transporters are the two main causes of MDR. Apollon and MDR1 are the most important and representative members, respectively, among the IAPs and ABC transporters. In the present study, we investigated the role of Apollon and MDR1 in chemotherapy resistance and their mechanism of interaction. We respectively knocked down the expression of Apollon and MDR1 using short hairpin RNA (shRNA) in adriamycin (ADM) resistant human CML K562 cells and examined the drug sensitivity, the consequences with regard to ADM accumulation and the alterations in the expression of Apollon and MDR1. The expression levels of Apollon and MDR1 mRNA were higher in the K562/ADM cells compared with the parental K562 cells as determined by reverse transcription‑polymerase chain reaction (RT-PCR). The plasmids of Apollon and MDR1 shRNA were respectively stably transfected into K562/ADM cells using Lipofectamine 2000. The transfection efficiency was detected by fluorescence microscopy. Cell Counting Kit-8 (CCK-8) assay revealed that Apollon or MDR1 knockdown significantly increased the chemosensitivity of the K562/ADM cells to ADM. Flow cytometric assay revealed that K562/ADM/shMDR1 cells exhibited a significantly increased intracellular accumulation of ADM, and that changes were not found in the K562/ADM/shApollon cells. Compared with the parental K562/ADM cells, a significantly decreased expression of Apollon mRNA and protein was determined in the K562/ADM/shApollon cells without affecting the expression of MDR1 as determined by RT-PCR and western blotting. Likewise, the expression levels of MDR1 mRNA and protein also markedly downregulated in the K562/ADM/shMDR1 cells had no effect on Apollon expression. Collectively, our findings demonstrated, for the first time, that downregulation of Apollon or MDR1 through stable transfection with the Apollon- or MDR1-targeting shRNA induced MDR reversal through respective inhibition of Apollon or MDR1 expression and function. However, the reversal mechanism of Apollon and MDR1 revealed no direct interaction with each other.

NSCA-1-a novel N-substituted coumalamide derivative-increases Adriamycin sensitivity in HepG2/adriamycin cells through modulating Akt/GSK-3β signaling and p53-dependant apoptotic pathway

Coumalamide derivatives are one of 2-pyrones derivatives, exerting multifunctional bioactivity. An array of coumalamide derivatives have been developed and presented good antiproliferative properties on cancer cells. However, the synthesis of 5-substituted coumalamide derivatives has not yet been published. Resistance to chemotherapeutic drugs is a major obstacle in hepatocellular carcinoma therapy. Recent evidence suggests that overexpression of constitutively active Akt confers on cancer cells resistance to chemotherapy. In this study, we report the synthesis and biological evaluation of a novel N-substituted coumalamide derivative (NSCA-1). The results indicated that NSCA-1 exerts synergistic cytotoxicity with Adriamycin in HepG2/ADR (HepG2/adriamycin) cells. Furthermore, both of the Akt kinase activity and phosphorylated Akt (Ser473) were found to be inhibited by NSCA-1 and subsequently resulting in decreased phosphorylation of GSK-3β. The intracellular accumulation of Adriamycin was also boosted by NSCA-1 via reducing the expression of p-gp. In addition, we found that combined treatment with NSCA-1 enhance cell apoptosis induced by Adriamycin via p53-dependant apoptotic pathway.

lncRNA UCA1 Contributes to Imatinib Resistance by Acting as a ceRNA Against miR-16 in Chronic Myeloid Leukemia Cells

Imatinib (IM) has been applied to the chronic phase of chronic myeloid leukemia (CML) and has great benefit on the prognosis of patients with CML. The function of drug efflux mediated by multidrug resistance protein-1 (MDR1) is considered as a main reason for IM drug resistance in CML cells. However, the exact mechanisms of MDR1 modulation in IM resistance of CML cells remain unclear. In the present study, long noncoding RNA (lncRNA) UCA1 was identified as an important modulator of MDR1 by a model system of leukemia cell lines with a gradual increase of MDR1 expression and IM resistance. Overexpression of UCA1 increased MDR1 expression to promote IM resistance of CML cells. Furthermore, for the first time, we demonstrated that UCA1 functions as a competitive endogenous (ceRNA) of MDR1 through completely binding the common miR-16. UCA1-MDR1 might be a novel target for enhancing the therapeutic efficacy of CML patients with IM resistance.

HOXB4 knockdown reverses multidrug resistance of human myelogenous leukemia K562/ADM cells by downregulating P-gp, MRP1 and BCRP expression via PI3K/Akt signaling pathway

Multidrug resistance (MDR) plays a pivotal role in human chronic myelogenous leukemia (CML) chemotherapy failure. MDR is mainly associated with the overexpression of drug efflux transporters of the ATP-binding cassette (ABC) proteins. Phosphoinositide 3-kinase (PI3K)/Akt signaling cascade is involved in the MDR phenotype and is correlated with multidrug resistance 1 (MDR1)/P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) expression in many human malignancies. Homeobox (HOX) B4, a member of the HOX gene family, has been reported to be correlated with occurrence, development, poor prognosis and drug resistance of human leukemia. In the present study, HOXB4 expression was analyzed in K562 cell line and its MDR subline K562/ADM. Compared with K562 cells, drug-resistant K562/ADM cells demonstrated evidently higher HOXB4 expression. In addition, we firstly investigated the reversal effect of HOXB4 deletion on K562/ADM cells and the underlying mechanism. The Cell Counting kit-8 (CCK-8) and flow cytometry assays showed that knockdown of HOXB4 enhanced chemosensitivity and decreased drug efflux in K562/ADM cells. Moreover, HOXB4 knockout led to downregulation of P-gp, MRP1 and BCRP expression and PI3K/Akt signaling activity, suggesting that repression of HOXB4 might be a key point to reverse MDR of K562/ADM cells.

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.