Combating P-glycoprotein-mediated multidrug resistance with 10-O-phenyl dihydroartemisinin ethers in MCF-7 cells

Ring-Contracted Artemisinin Derivatives as Novel CDK 4/6 Inhibitors: Synthesis and Anti-Breast Cancer Evaluation

The endoperoxide group of artemisinins is universally accepted an essential group for their anti-cancer effects. In this study, a series of D-ring-contracted artemisinin derivatives were constructed by combining ring-contracted artemisinin core with fragments of functional heterocyclic molecules or classical CDK4/6 inhibitors to identify more efficacious breast cancer treatment agents. Twenty-six novel hybridized molecules were synthesized and characterized by HRMS, IR, 1H-NMR and 13C NMR. In antiproliferative activities and kinase inhibitory effects assays, we found that the antiproliferative effects of B01 were close to those of the positive control Palbociclib, with GI50 values of 4.87±0.23 μM and 9.97±1.44 μM towards T47D cells and MDA-MB-436 cells respectively. In addition, the results showed that B01 was the most potent compound against CDK6/cyclin D3 kinase, with an IC50 value of 0.135±0.041 μM, and its activity was approximately 1/3 of the positive control Palbociclib.

A (Traditional Chinese Medicine) TCM-Inspired Doxorubicin Resistance Reversing Strategy: Preparation, Characterization, and Application of a Co-loaded pH-Sensitive Liposome

In this study, nano-strategy for combined medication of active compounds from traditional Chinese medicine herbs was proposed to achieve the synergistic effects of inhibiting the doxorubicin (DOX) resistance, reducing the cardio-toxicity, and improving the treatment efficacy simultaneously. Dihydroartemisinin (DHA) and tetrandrine (TET) were co-delivered for the first time to treat DOX resistance of breast cancer with multi-pathway mechanism. Tumor micro-environment sensitivity prescription was adopted to enhance the reversal effect of DOX resistance nearly 50 times (resistance index, RI was 46.70) and uptake ability. The DHA-TET pH-sensitive liposomes (DHA-TET pH-sensitive LPs) had a good spherical structure and a uniform dispersion structure with particle size, polydispersity index (PDI), and zeta potential of 112.20 ± 4.80 nm, 0.20 ± 0.02, and - 8.63 ± 0.74 Mv, and was stable until 14 days under the storage environment of 4°C and for 6 months at room temperature environment. With the DOX resistance reversing ability increased, the inhibition effect of DHA-TET pH-sensitive LPs on both MCF-7/ADR cells and MCF-7 cells was significantly enhanced; meanwhile, the toxicity on cardiac cell (H9c2) was lowered. Ferroptosis induced by the DHA was investigated showing that the intracellular reactive oxygen species (ROS) and lipid peroxidation were increased to promote the synergistic effect through the due-loaded nano-carrier, providing a promising alternative for future clinical application.

Nano Strategies for Artemisinin Derivatives to Enhance Reverse Efficiency of Multidrug Resistance in Breast Cancer

Artemisinin (ART) has been found to exert anti-tumor activity by regulating the cell cycle, inducing apoptosis, inhibiting angiogenesis and tumor invasion and metastasis. Its derivatives (ARTs) can regulate the expression of drug-resistant proteins and reverse the multidrug resistance (MDR) of tumor cells by inhibiting intracellular drug efflux, inducing apoptosis and autophagy of tumor cells, thus enhancing the sensitivity of tumor cells to chemotherapy and radiotherapy. Recent studies have shown that nanodrugs play an important role in the diagnosis and treatment of cancer, which can effectively solve the shortcomings of poor hydrophilicity and low bioavailability of ARTs in the human body, prolong the in vivo circulation time, improve the targeting of drugs (including tumor tissues or specific organelles), and control the release of drugs in target tissues, thereby reducing the side effect. This review systematically summarized the latest research progress of nano-strategies of ARTs to enhance the efficiency of MDR reversal in breast cancer (BC) from the following two aspects: (1) Chemicals encapsulated in nanomaterials based on innovative anti-proliferation mechanism: non-ABC transporter receptor candidate related to ferroptosis (dihydroartemisinin/DHA analogs). (2) Combination therapy strategy of nanomedicine (drug-drug combination therapy, drug-gene combination, and chemical-physical therapy). Self-assembled nano-delivery systems enhance therapeutic efficacy through increased drug loading, rapid reactive release, optimized delivery sequence, and realization of cascade-increasing effects. New nanotechnology methods must be designed for specific delivery routines to achieve targeting administration and overcome MDR without affecting normal cells. The significance of this review is to expect that ART and ARTs can be widely used in clinical practice. In the future, nanotechnology can help people to treat multidrug resistance of breast cancer more accurately and efficiently.

Pleiotropic Roles of ABC Transporters in Breast Cancer

Chemotherapeutics are the mainstay treatment for metastatic breast cancers. However, the chemotherapeutic failure caused by multidrug resistance (MDR) remains a pivotal obstacle to effective chemotherapies of breast cancer. Although in vitro evidence suggests that the overexpression of ATP-Binding Cassette (ABC) transporters confers resistance to cytotoxic and molecularly targeted chemotherapies by reducing the intracellular accumulation of active moieties, the clinical trials that target ABCB1 to reverse drug resistance have been disappointing. Nevertheless, studies indicate that ABC transporters may contribute to breast cancer development and metastasis independent of their efflux function. A broader and more clarified understanding of the functions and roles of ABC transporters in breast cancer biology will potentially contribute to stratifying patients for precision regimens and promote the development of novel therapies. Herein, we summarise the current knowledge relating to the mechanisms, functions and regulations of ABC transporters, with a focus on the roles of ABC transporters in breast cancer chemoresistance, progression and metastasis.

Therapeutic Potentials and Mechanisms of Artemisinin and its Derivatives for Tumorigenesis and Metastasis

BACKGROUND

Tumor recurrence and metastasis are still leading causes of cancer mortality worldwide. The influence of traditional treatment strategies against metastatic tumors may still be limited. To search for novel and powerful agents against tumors has become a major research focus. In this study, Artemisinin (ARM), a natural compound isolated from herbs, Artemisia annua L., proceeding from drug repurposing methods, attracts more attention due to its good efficacy and tolerance in antimalarial practices, as well as newly confirmed anticancer activity.

METHODS

We have searched and reviewed the literatures about ARM and its derivatives (ARMs) for cancer using keywords "artemisinin" until May 2019.

RESULTS

In preclinical studies, ARMs can induce cell cycle arrest and cell death by apoptosis etc., to inhibit the progression of tumors, and suppress EMT and angiogenesis to inhibit the metastasis of tumors. Notably, the complex relationships of ARMs and autophagy are worth exploring. Inspired by the limitations of its antimalarial applications and the mechanical studies of artemisinin and cancer, people are also committed to develop safer and more potent ARM-based modified compounds (ARMs) or combination therapy, such as artemisinin dimers/ trimers, artemisinin-derived hybrids. Some clinical trials support artemisinins as promising candidates for cancer therapy.

CONCLUSION

ARMs show potent therapeutic potentials against carcinoma including metastatic tumors. Novel compounds derived from artemisinin and relevant combination therapies are supposed to be promising treatment strategies for tumors, as the important future research directions.

Structural optimization and biological evaluation for novel artemisinin derivatives against liver and ovarian cancers

An increasing number of artemisinin (ARS) and its derivatives have been reported for their potential therapeutic value of human cancer. However, their therapeutic potencies are limited owing to their poor pharmacokinetic profiles. Our previous studies showed that a lead compound ARS4 originated from incorporating the pharmacophore of the approved chemotherapeutic agent melphalan into the basic skeleton of artemisinin with a succinic linker exhibited an excellent toxicity to human ovarian cancer cells and low cytotoxicity to normal cells. The mechanism studies demonstrated that it inhibited the growth and proliferation of ovarian cancer cells and resulted in S-phase arrest, apoptosis and inhibition of migration. Meanwhile, it exhibited excellent antitumor activities in animal models. Herein, further structure optimization for this lead compound ARS4 was performed and nineteen novel derivatives were designed and synthesized. Among them, compounds 10-12, 15, 16, 18 and 19 demonstrated powerful cytotoxic effects against human liver cancer and ovarian cancer cell lines, with their IC_50s below 0.86 μM against Hep3B and A2780 cell lines, which are superior to that of ARS4. Four compounds (11, 15, 16 and 18) were selected to further evaluate their antitumor activities in in vitro and in vivo ovarian and liver cancer models, the results indicated that compound 18 exhibited the best therapeutic effect, not only effectively inhibited the growth of 7404 xenograft and Huh7 xenograft, but also presented a good dose-dependent inhibition toward the growth of A2780 xenograft. Overall, based on these positive results, these novel chemical structures may provide a new inspiration for the discovery of novel antitumor agents originated from artemisinin scaffolds.

Dihydroartemisinin-Loaded Magnetic Nanoparticles for Enhanced Chemodynamic Therapy

Recently, chemodynamic therapy (CDT) has represented a new approach for cancer treatment with low toxicity and side effects. Nonetheless, it has been a challenge to improve the therapeutic effect through increasing the amount of reactive oxygen species (ROS). Herein, we increased the amount of ROS agents in the Fenton-like reaction by loading dihydroartemisinin (DHA) which was an artemisinin (ART) derivative containing peroxide groups, into magnetic nanoparticles (MNP), thereby improving the therapeutic effect of CDT. Blank MNP were almost non-cytotoxic, whereas three MNP loading ART-based drugs, MNP-ART, MNP-DHA, and MNP-artesunate (MNP-AS), all showed significant killing effect on breast cancer cells (MCF-7 cells), in which MNP-DHA were the most potent. What's more, the MNP-DHA showed high toxicity to drug-resistant breast cancer cells (MCF-7/ADR cells), demonstrating its ability to overcome multidrug resistance (MDR). The study revealed that MNP could produce ferrous ions under the acidic condition of tumor microenvironment, which catalyzed DHA to produce large amounts of ROS, leading to cell death. Further experiments also showed that the MNP-DHA had significant inhibitory effect on another two aggressive breast cancer cell lines (MDA-MB-231 and MDA-MB-453 cells), which indicated that the great potential of MNP-DHA for the treatment of intractable breast cancers.

Interactions between artemisinin derivatives and P-glycoprotein

BACKGROUND

Artemisinin was isolated and identified in 1972, which was the starting point for a new era in antimalarial drug therapy. Furthermore, numerous studies have demonstrated that artemisinin and its derivatives exhibit considerable anticancer activity both in vitro, in vivo, and even in clinical Phase I/II trials. P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) is one of the most serious causes of chemotherapy failure in cancer treatment. Interestingly, many artemisinin derivatives exhibit excellent ability to overcome P-gp mediated MDR and even show collateral sensitivity against MDR cancer cells. Furthermore, some artemisinin derivatives show P-gp-mediated MDR reversal activity. Therefore, the interaction between P-gp and artemisinin derivatives is important to develop novel combination treatment protocols with artemisinin derivatives and established anticancer drugs that are P-gp substrates.

PURPOSE

This systematic review provides an updated overview on the interaction between artemisinin derivatives and P-gp and the effect of artemisinin derivatives on the P-gp expression level.

RESULTS

Artemisinin derivatives exhibit multi-specific interactions with P-gp. The currently used artemisinin derivatives are not transported by P-gp. However, some of novel synthetized artemisinin derivatives exhibit P-gp substrate properties. Furthermore, many artemisinin derivatives act as P-gp inhibitors, which exhibit the potential to reverse MDR towards clinically used anticancer drugs.

CONCLUSION

Therefore, studies on the interaction between artemisinin derivatives and P-gp provide important information for the development of novel anti-cancer artemisinin derivatives to reverse P-gp mediated MDR and for the design of rational artemisinin-based combination therapies against cancer.

Effects of Piperazine Derivative on Paclitaxel Pharmacokinetics

Paclitaxel (PTX) is an anticancer agent that is used to treat many cancers but it has a very low oral bioavailability due, at least in part, to the drug efflux transporter, P-glycoprotein (P-gp). Therefore, this study was performed to enhance oral bioavailability of PTX. In this study, we investigated the effects of several piperazine derivatives on P-gp function in vitro. Compound 4 was selected as the most potent P-gp inhibitor from the in vitro results for examining the pharmacokinetic (PK) changes of PTX in rats. Compound 4 increased the AUC_inf of PTX without alterations in the C_max value. The elimination half-life was extended and the oral clearance decreased. Additionally, the T_max was delayed or widened in the treatment groups. Therefore, the bioavailability (BA) of PTX was improved 2.1-fold following the co-administration of 5 mg/kg of the derivative. A piperazine derivative, compound 4, which was confirmed as a substantial P-gp inhibitor in vitro increased the BA of PTX up to 2-fold by a lingering absorption, in part due to inhibition of intestinal P-gp and a low oral clearance of PTX. These results suggest that co-administering compound 4 may change the PK profile of PTX by inhibiting P-gp activity in the body.

Transcriptome analysis of genes associated with breast cancer cell motility in response to Artemisinin treatment

Background

Well-known anti-malarial drug artemisinin exhibits potent anti-cancerous activities. In-vivo and in-vitro studies showed its anti-tumor and immunomodulatory properties signifying it as a potent drug candidate for study. The studies of mechanisms of cell movement are relevant which can be understood by knowing the involvement of genes in an effect of a drug. Although cytotoxicity and anti-proliferative activity of artemisinin is evident, the genes participating in its anti-migratory and reduced invasive effect are not well studied. The present study reports the alteration in the expression of 84 genes involved in cell motility upon artemisinin treatment in MCF-7 breast cancer cells using pathway focused gene expression PCR array. In addition, the effect of artemisinin on epigenetic modifier HDACs is studied.

Methods

We checked the functional stimulus of artemisinin on cell viability, migration, invasion and apoptosis in breast cancerous cell lines. Using qRT-PCR and western blot, we validated the altered expression of relevant genes associated with proliferation, migration, invasion, apoptosis and mammary gland development.

Results

Artemisinin inhibited cell proliferation of estrogen receptor negative breast cancer cells with fewer efficacies in comparison to estrogen receptor positive ones. At the same time, cell viability and proliferation of normal breast epithelial MCF10A cells was un-affected. Artemisinin strongly inhibited cancer cell migration and invasion. Along with orphan nuclear receptors (ERRα, ERRβ and ERRγ), artemisinin altered the ERα/ERβ/PR/Her expression status of MCF-7 cells. The expression of genes involved in the signaling pathways associated with proliferation, migration, invasion and apoptosis was significantly altered which cooperatively resulted into reduced growth promoting activities of breast cancer cells. Interestingly, artemisinin exhibited inhibitory effect on histone deacetylases (HDACs).

Conclusions

Upregulated expression of tumor suppressor genes along with reduced expression of oncogenes significantly associated with growth stimulating signaling pathways in response to artemisinin treatment suggests its efficacy as an effective drug in breast cancer treatment.

The efficacy of WGA modified daunorubicin anti-resistant liposomes in treatment of drug-resistant MCF-7 breast cancer

BACKGROUND

Breast cancer is the most common malignancy and remains a leading cause of cancer-related deaths in female. Chemotherapy failure of breast cancer is mainly associated with multidrug resistance of cancer cells.

PURPOSE

The WGA modified daunorubicin anti-resistant liposomes were developed for circumventing the multidrug resistance and eliminating cancer cells.

METHODS

WGA was modified on liposomal surface for increasing the intracellular uptake. Tetrandrine was inserted into the phospholipid bilayer for reversing cancer drug-resistance, and daunorubicin was encapsulated in liposomal aqueous core as an anticancer agent. Evaluations were performed on MCF-7 cells, MCF-7/ADR cells and xenografts of MCF-7/ADR cells.

RESULTS

In vitro results showed that WGA modified daunorubicin anti-resistant liposomes exhibited suitable physicochemical properties, significantly increased intracellular uptake in both MCF-7 cells and MCF-7/ADR cells, and circumvented the multidrug resistance via inhibiting P-gp. In vivo results demonstrated that the targeting liposomes showed a long-circulatory effect in blood system, and could remarkably accumulate at the tumor location. The involved action mechanisms for the enhanced anticancer efficacy were activation of pro-apoptotic proteins (Bax and Bok), apoptotic enzymes (caspase 8, caspase 9 and caspase 3).

CONCLUSION

The established WGA modified daunorubicin anti-resistant liposomes could provide a potential strategy for treating resistant MCF-7 breast cancer.