Drug membrane transporters and CYP3A4 are affected by hypericin, hyperforin or aristoforin in colon adenocarcinoma cells

Extracellular Vesicles as Surrogates for the Regulation of the Drug Transporters ABCC2 (MRP2) and ABCG2 (BCRP)

Drug efflux transporters of the ATP-binding-cassette superfamily play a major role in the availability and concentration of drugs at their site of action. ABCC2 (MRP2) and ABCG2 (BCRP) are among the most important drug transporters that determine the pharmacokinetics of many drugs and whose overexpression is associated with cancer chemoresistance. ABCC2 and ABCG2 expression is frequently altered during treatment, thus influencing efficacy and toxicity. Currently, there are no routine approaches available to closely monitor transporter expression. Here, we developed and validated a UPLC-MS/MS method to quantify ABCC2 and ABCG2 in extracellular vesicles (EVs) from cell culture and plasma. In this way, an association between ABCC2 protein levels and transporter activity in HepG2 cells treated with rifampicin and hypericin and their derived EVs was observed. Although ABCG2 was detected in MCF7 cell-derived EVs, the transporter levels in the vesicles did not reflect the expression in the cells. An analysis of plasma EVs from healthy volunteers confirmed, for the first time at the protein level, the presence of both transporters in more than half of the samples. Our findings support the potential of analyzing ABC transporters, and especially ABCC2, in EVs to estimate the transporter expression in HepG2 cells.

Cytotoxic and Antibacterial Prenylated Acylphloroglucinols from Hypericum olympicum L

Two new bicyclo[3.3.1]nonane type bicyclic polyprenylated acylphloroglucinol derivatives (BPAPs), olympiforin A and B as well as three known prenylated phloroglucinols, were isolated from the aerial parts of Hypericum olympicum L. The structures of the isolated compounds were established by means of spectral techniques (HRESIMS and 1D and 2D NMR). All compounds were tested on a panel of human tumor (MDA-MB-231, EJ, K-562, HL-60 and HL-60/DOX) and non- tumorigenic (HEK-293 and EA.hy926) cell lines using the MTT assay. All tested compounds exerted significant in vitro cytotoxicity with IC₅₀ values ranging from 1.2 to 24.9 μM and from 0.9 to 34 μM on tumor and non-cancerous cell lines, respectively. Most of the compounds had good selectivity and were more cytotoxic to the tumor cell lines than to the normal ones. A degradation of the precursor caspase 9 for some of the compounds was observed; therefore, the intrinsic pathway of apoptosis is the most likely mechanism of cytotoxic activity. The BPAPs were examined for antibacterial and antibiofilm activity through the broth microdilution method and the protocol of Stepanović. They showed a moderate effect against Enterococcus faecalis and Streptococcus pyogenes but a very profound activity against Staphylococcus aureus with minimum inhibitory concentrations (MIC) in the range of 0.78-2 mg/L. Olympiforin B also had a great effect against methicillin-resistant S. aureus (MRSA) with an MIC value of 1 mg/L and a very significant antibiofilm activity on that strain with a minimum biofilm inhibition concentration (MBIC) value of 0.5 mg/L. The structures of the isolated compounds were in silico evaluated using ADME and drug likeness tests.

Hypericin: A natural anthraquinone as promising therapeutic agent

BACKGROUND

Hypericin is a prominent secondary metabolite mainly existing in genus Hypericum. It has become a research focus for a quiet long time owing to its extensively pharmacological activities especially the anti-cancer, anti-bacterial, anti-viral and neuroprotective effects. This review concentrated on summarizing and analyzing the existing studies of hypericin in a comprehensive perspective.

METHODS

The literature with desired information about hypericin published after 2010 was gained from electronic databases including PubMed, SciFinder, Science Direct, Web of Science, China National Knowledge Infrastructure databases and Wan Fang DATA.

RESULTS

According to extensive preclinical and clinical studies conducted on the hypericin, an organized and comprehensive summary of the natural and artificial sources, strategies for improving the bioactivities, pharmacological activities, drug combination of hypericin was presented to explore the future therapeutic potential of this active compound.

CONCLUSIONS

Overall, this review offered a theoretical guidance for the follow-up research of hypericin. However, the pharmacological mechanisms, pharmacokinetics and structure activity relationship of hypericin should be further studied in future research.

Hyperforin: A natural lead compound with multiple pharmacological activities

Hypericum perforatum L. (Clusiaceae), commonly known as St. John's wort, has a rich historical background as one of the oldest and most widely studied herbal medicines. Hyperforin is the main antidepressant active ingredient of St. John's wort. In recent years, hyperforin has attached increasing attention due to its multiple pharmacological activities. In this review, the information on hyperforin was systematically summarized. Hyperforin is considered to be a lead compound with diverse pharmacological activities including anti-depression, anti-tumor, anti-dementia, anti-diabetes and others. It can be obtained by extraction and synthesis. Further pharmacological studies and more precise detection methods will help develop a value for hyperforin. In addition, structural modification and pharmaceutical preparation technology will be beneficial to promoting the research progress of hyperforin based innovative drugs. Although these works are full of known and unknown challenges, researchers are still expected to make hyperforin play a greater value.

Phytochemicals That Interfere With Drug Metabolism and Transport, Modifying Plasma Concentration in Humans and Animals

Phytochemicals (Pch) present in fruits, vegetables and other foods, are known to inhibit or induce drug metabolism and transport. An exhaustive search was performed in five databases covering from 2000 to 2021. Twenty-one compounds from plants were found to modulate CYP3A and/or P-gp activities and modified the pharmacokinetics and the therapeutic effect of 27 different drugs. Flavonols, flavanones, flavones, stilbenes, diferuloylmethanes, tannins, protoalkaloids, flavans, hyperforin and terpenes, reduce plasma concentration of cyclosporine, simvastatin, celiprolol, midazolam, saquinavir, buspirone, everolimus, nadolol, tamoxifen, alprazolam, verapamil, quazepam, digoxin, fexofenadine, theophylline, indinavir, clopidogrel. Anthocyanins, flavonols, flavones, flavanones, flavonoid glycosides, stilbenes, diferuloylmethanes, catechin, hyperforin, alkaloids, terpenes, tannins and protoalkaloids increase of plasma concentration of buspirone, losartan, diltiazem, felodipine, midazolam, cyclosporine, triazolam, verapamil, carbamazepine, diltiazem, aripiprazole, tamoxifen, doxorubicin, paclitaxel, nicardipine. Interactions between Pchs and drugs affect the gene expression and enzymatic activity of CYP3A and P-gp transporter, which has an impact on their bioavailability; such that co-administration of drugs with food, beverages and food supplements can cause a subtherapeutic effect or overdose. Therefore, it is important for the clinician to consider these interactions to obtain a better therapeutic effect.

Ultrasound Triggers Hypericin Activation Leading to Multifaceted Anticancer Activity

The use of ultrasound (US) in combination with a responsive chemical agent (sonosensitizer) can selectively trigger the agent's anticancer activity in a process called sonodynamic therapy (SDT). SDT shares some properties with photodynamic therapy (PDT), which has been clinically approved, but sets itself apart because of its use of US rather than light to achieve better tissue penetration. SDT provides anticancer effects mainly via the sonosensitizer-mediated generation of reactive oxygen species (ROS), although the precise nature of the underpinning mechanism is still under debate. This work investigates the SDT anticancer activity of hypericin (Hyp) in vitro in two- (2D) and three-dimensional (3D) HT-29 colon cancer models, and uses PDT as a yardstick due to its well-known Hyp phototoxicity. The cancer cell uptake and cellular localization of Hyp were investigated first to determine the proper noncytotoxic concentration and incubation time of Hyp for SDT. Furthermore, ROS production, cell proliferation, and cell death were evaluated after Hyp was exposed to US. Since cancer relapse and transporter-mediated multidrug resistance (MDR) are important causes of cancer treatment failure, the US-mediated ability of Hyp to elicit immunogenic cell death (ICD) and overcome MDR was also investigated. SDT showed strong ROS-mediated anticancer activity 48 h after treatment in both the HT-29 models. Specific damage-associated molecular patterns that are consistent with ICD, such as calreticulin (CRT) exposure and high-mobility group box 1 protein (HMGB1) release, were observed after SDT with Hyp. Moreover, the expression of the ABC transporter, P-glycoprotein (P-gp), in HT-29/MDR cells was not able to hinder cancer cell responsiveness to SDT with Hyp. This work reveals, for the first time, the US responsiveness of Hyp with significant anticancer activity being displayed, making it a full-fledged sonosensitizer for the SDT of cancer.

Hypericin Enhances Paclitaxel-Induced B16-F10 Cell Apoptosis by Activating a Cytochrome c Release-Dependent Pathway

The enhanced inhibitory effect of paclitaxel (PTX) combined with hypericin (HY) on B16-F10 cells may be realized through the ROS-related cytochrome c release pathway. The apoptotic characteristics of the B16-F10 cells, such as DNA fragmentation, chromatin condensation, and apoptotic body formation, were all enhanced in the combined treatment group. Further investigation showed that the combination of paclitaxel and HY could increase the level of mitochondrial damage and the concentration of cytochrome c, causing the expression of caspase-3 and the cleavage of PARP.¹. Compared with paclitaxel or HY alone, the level of reactive oxygen species (ROS) increased significantly, while glutathione reductase (GR) activity and intracellular glutathione (GSH) levels decreased significantly in the combination group.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Hypericin-mediated photodynamic therapy for the treatment of cancer: a review

OBJECTIVES

Hypericin is a polycyclic aromatic naphthodianthrone that occurs naturally. It is also an active ingredient in some species of the genus Hypericum. Emerging evidence suggests that hypericin has attracted great attention as a potential anticancer drug and exhibits remarkable antiproliferative effect upon irradiation on various tumour cells. This paper aims to summarise the anticancer effect and molecular mechanisms modulated by hypericin-medicated photodynamic therapy and its potential role in the cancer treatment.

KEY FINDINGS

Hypericin-medicated photodynamic therapy could inhibit the proliferation of various tumour cells including bladder, colon, breast, cervical, glioma, leukaemia, hepatic, melanoma, lymphoma and lung cancers. The effect is primarily mediated by p38 mitogen-activated protein kinase (MAPK), JNK, PI3K, CCAAT-enhancer-binding protein homologous protein (CHOP)/TRIB3/Akt/mTOR, TRAIL/TRAIL-receptor, c-Met and Ephrin-Eph, the mitochondria and extrinsic signalling pathways. Furthermore, hypericin-medicated photodynamic therapy in conjunction with chemotherapeutic agents or targeted therapies is more effective in inhibiting the growth of tumour cells.

SUMMARY

During the past few decades, the anticancer properties of photoactivated hypericin have been extensively investigated. Hypericin-medicated photodynamic therapy can modulate a variety of proteins and genes and exhibit a great potential to be used as a therapeutic agent for various types of cancer.

Mycotoxins: Biotransformation and Bioavailability Assessment Using Caco-2 Cell Monolayer

The determination of mycotoxins content in food is not sufficient for the prediction of their potential in vivo cytotoxicity because it does not reflect their bioavailability and mutual interactions within complex matrices, which may significantly alter the toxic effects. Moreover, many mycotoxins undergo biotransformation and metabolization during the intestinal absorption process. Biotransformation is predominantly the conversion of mycotoxins meditated by cytochrome P450 and other enzymes. This should transform the toxins to nontoxic metabolites but it may possibly result in unexpectedly high toxicity. Therefore, the verification of biotransformation and bioavailability provides valuable information to correctly interpret occurrence data and biomonitoring results. Among all of the methods available, the in vitro models using monolayer formed by epithelial cells from the human colon (Caco-2 cell) have been extensively used for evaluating the permeability, bioavailability, intestinal transport, and metabolism of toxic and biologically active compounds. Here, the strengths and limitations of both in vivo and in vitro techniques used to determine bioavailability are reviewed, along with current detailed data about biotransformation of mycotoxins. Furthermore, the molecular mechanism of mycotoxin effects is also discussed regarding the disorder of intestinal barrier integrity induced by mycotoxins.

Bicyclic polyprenylated acylphloroglucinols and their derivatives: structural modification, structure-activity relationship, biological activity and mechanism of action

Bicyclic polyprenylated acylphloroglucinols (BPAPs), the principal bioactive benzophenone products isolated from plants of genera Garcinia and Hypericum, have attracted noticeable attention from the synthetic and biological communities due to their fascinating chemical structures and promising biological activities. However, the potential drug interaction, undesired physiochemical properties and toxicity have limited their potential use and development. In the last decade, pharmaceutical research on the structural modifications, structure-activity relationships (SARs) and mechanisms of action of BPAPs has been greatly developed to overcome the challenges. A comprehensive review of these scientific literature is extremely needed to give an overview of the rapidly emerging area and facilitate research related to BPAPs. This review, containing over 226 references, covers the progress made in the chemical synthesis-based structure modifications, SARs and the mechanism of action of BPAPs in vivo and vitro. The most relevant articles will focus on the discovery of lead compounds via synthetic modifications and the important BPAPs for which the direct targets have been deciphered. From this review, several key points of the SARs and mode of actions of this novel class of compounds have been summarized. The perspective and future direction of the research on BPAPs are concluded. This review would be helpful to get a better grasp of medicinal research of BPAPs and become a compelling guide for chemists dedicated to the synthesis of these compounds.

The role of ABCG2 in modulating responses to anti-cancer photodynamic therapy

The ATP-binding cassette (ABC) superfamily G member 2 (ABCG2) transmembrane protein transporter is known for conferring resistance to treatment in cancers. Photodynamic therapy (PDT) is a promising anti-cancer method involving the use of light-activated photosensitisers to precisely induce oxidative stress and cell death in cancers. ABCG2 can efflux photosensitisers from out of cells, reducing the capacity of PDT and limiting the efficacy of treatment. Many studies have attempted to elucidate the relationship between the expression of ABCG2 in cancers, its effect on the cellular retention of photosensitisers and its impact on PDT. This review looks at the studies which investigate the effect of ABCG2 on a range of different photosensitisers in different pre-clinical models of cancer. This work also evaluates the approaches that are being investigated to address the role of ABCG2 in PDT with an outlook on potential clinical validation.

Breast cancer resistance protein is the enemy of hypericin accumulation and toxicity of hypericin-mediated photodynamic therapy

Breast cancer resistance protein (BCRP) belongs to the family of ATP-binding cassette (ABC) transporters, overexpression of which can confer a multidrug-resistant phenotype in cancer cells and tumors. BCRP mediates efflux of numerous xenobiotics, including various chemotherapeutic agents and photosensitizers. Hypericin (HY) is a naturally-occurring photosensitizer synthesized by plants of the genus Hypericum. Our recently published results indicate that accumulation of HY in cancer cells of different tissue origin can be affected mostly by BCRP. Considering all known facts, the main goal of this study was to verify whether not only HY accumulation but also toxicity of HY-mediated photodynamic therapy (PDT) can be affected by the presence of some ABC transporters. To specifically prove our hypothesis, we used an experimental model of human leukemia cell lines differing in the expression level of the main drug efflux transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and BCRP. The lowest HY accumulation, and consequently the highest resistance to HY-PDT, was found in cells overexpressing BCRP. Moreover, pretreatment with BCRP inhibitor Ko143 significantly increased HY accumulation and sensitized cells to HY-PDT. Therefore, our findings represent direct evidence that BCRP is the nemesis of HY accumulation and toxicity of HY-PDT. Thus, we should emphasize that individualized screening for BCRP expression and activity may represent a useful tool for prediction of HY-mediated photodynamic diagnosis (PDD) or PDT effectiveness.

miR-34a Regulates Multidrug Resistance via Positively Modulating OAZ2 Signaling in Colon Cancer Cells

Although aberrant expression of miR-34a, an essential tumor suppressor miRNA, has been frequently observed in colon cancer (CCa), whether miR-34a can regulate CCa progression by modulating other facets of this malignancy (such as multidrug resistance, MDR) remains unknown. Here, we report for the first time that miR-34a expression was significantly downregulated in clinical CCa samples from oxaliplatin-resistant patients and in experimentally established multidrug-resistant CCa cells. By using histoculture drug response assay, we further confirmed that clinical CCa samples with lower miR-34a expression appeared to be more resistant to chemotherapy. Functionally, ectopic expression of exogenous miR-34a resensitized multidrug-resistant HCT-8/OR cells to oxaliplatin treatment, whereas miR-34a inhibition augmented the oxaliplatin resistance in chemosensitive HCT-8 cells. Mechanistically, miR-34a positively regulated the mRNA stability of the ornithine decarboxylase antizyme 2 (OAZ2) by directly targeting its three prime untranslated region (3′UTR). Consequently, suppression of the expression of miR-34a/OAZ2 signaling by chemotherapeutic agents significantly enhanced the activation of MDR-associated ATP-binding cassette (ABC) transporters and antiapoptosis pathways, thus leading to MDR development in CCa cells. Collectively, our combined analysis reveals a critical role of miR-34a/OAZ2 cascade in conferring a proper cellular response to CCa chemotherapy.

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.