The pro-apoptotic and anti-invasive effects of hypericin-mediated photodynamic therapy are enhanced by hyperforin or aristoforin in HT-29 colon adenocarcinoma cells

Photodynamic Therapy and Immunological View in Gastrointestinal Tumors

Gastrointestinal cancers are a specific group of oncological diseases in which the location and nature of growth are of key importance for clinical symptoms and prognosis. At the same time, as research shows, they pose a serious threat to a patient's life, especially at an advanced stage of development. The type of therapy used depends on the anatomical location of the cancer, its type, and the degree of progression. One of the modern forms of therapy used to treat gastrointestinal cancers is PDT, which has been approved for the treatment of esophageal cancer in the United States. Despite the increasingly rapid clinical use of this treatment method, the exact immunological mechanisms it induces in cancer cells has not yet been fully elucidated. This article presents a review of the current understanding of the mode of action of photodynamic therapy on cells of various gastrointestinal cancers with an emphasis on colorectal cancer. The types of cell death induced by PDT include apoptosis, necrosis, and pyroptosis. Anticancer effects are also a result of the destruction of tumor vasculature and activation of the immune system. Many reports exist that concern the mechanism of apoptosis induction, of which the mitochondrial pathway is most often emphasized. Photodynamic therapy may also have a beneficial effect on such aspects of cancer as the ability to develop metastases or contribute to reducing resistance to known pharmacological agents.

Hypericin as a promising natural bioactive naphthodianthrone: A review of its pharmacology, pharmacokinetics, toxicity, and safety

Hypericin can be derived from St. John's wort, which is widely spread around the world. As a natural product, it has been put into clinical practice such as wound healing and depression for a long time. In this article, we review the pharmacology, pharmacokinetics, and safety of hypericin, aiming to introduce the research advances and provide a full evaluation of it. Turns out hypericin, as a natural photosensitizer, exhibits an excellent capacity for anticancer, neuroprotection, and elimination of microorganisms, especially when activated by light, potent anticancer and antimicrobial effects are obtained after photodynamic therapy. The mechanisms of its therapeutic effects involve the induction of cell death, inhibition of cell cycle progression, inhibition of the reuptake of amines, and inhibition of virus replication. The pharmacokinetics properties indicate that hypericin has poor water solubility and bioavailability. The distribution and excretion are fast, and it is metabolized in bile. The toxicity of hypericin is rarely reported and the conventional use of it rarely causes adverse effects except for photosensitization. Therefore, we may conclude that hypericin can be used safely and effectively against a variety of diseases. We hope to provide researchers with detailed guidance and enlighten the development of it.

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.

Exploring the Role of Phytochemicals as Potent Natural Photosensitizers in Photodynamic Therapy

BACKGROUND

Cancer is still considered a deadly disease worldwide due to difficulties in diagnosis, painful treatment procedures, costly therapies, side effects, and cancer relapse. Cancer treatments using conventional methods like chemotherapy and radiotherapy were not convincing due to its post-treatment toxicity in the host. In Photodynamic Therapy (PDT), three individual non-toxic components including a photosensitizer, light source and oxygen cause damage to the cells and tissues when they are combined.

OBJECTIVE

In recent years, phytochemicals are being increasingly recognized as potent complementary drugs for cancer because of its natural availability, less toxicity and therapeutic efficiency in par with commercial drugs. Hence, the idea of using phytochemicals as natural photosensitizers in PDT resulted in a multiple pool of research studies with promising results in preclinical and clinical investigations.

METHODS

In this review, the potential of phytochemicals to act as natural photosensitizers for PDT, their mode of action, drawbacks, challenges and possible solutions are discussed in detail.

RESULTS

In PDT, natural photosensitizers, when used alone or in combination with other photosensitizers, induced cell death by apoptosis and necrosis, increased oxidative stress, altered cancer cell death signaling pathways, increased cytotoxicity and DNA damage in cancer cells. The pro-oxidant nature of certain antioxidant polyphenols, hormesis phenomenon, Warburg effect and DNA damaging potential plays a significant role in the photosensitizing mechanism of phytochemicals in PDT.

CONCLUSION

This review explores the role of phytochemicals that can act as photosensitizers alone or in combination with PDT and its mechanism of action on different cancers.

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.

In vitro study of disodium cromoglicate as a novel effective hydrotrope solvent for hypericin utilisation in photodynamic therapy

Hypericin (HY) is a naphthodianthrone that naturally occurs in Hypericum perforatum L. It is a promising photosensitiser used in photodynamic therapy for and diagnosis of oncological diseases. However, its hydrophobic character is an obstacle that has prevented its efficient use. The commonly used solvent, dimethyl sulfoxide (DMSO), is a controversial constituent of HY formulations and its use has been rejected by many researchers studying HY both in vitro and in vivo. In this study, we propose the utilisation of hydrotropy to solubilise HY in an aqueous environment. Cromolyn (DSCG) is a non-toxic, well-tolerated, antiallergic drug that has been employed in clinical practice since 1970, and in aqueous solution it acts as a hydrotrope. At a molecular ratio of 1:12,000 HY to DSCG, the compound is able to solubilise HY in aqueous environment. In an HT-29 cell suspension, DSCG (1.8 mmol L-1) considerably enhances the interaction between HY (150 nmol L-1) and HT-29 cells, which leads to an HY fluorescence emission increase with a half-time approximately 2 min compared to 29 min for samples that lack DSCG. Studies using HT-29 adenocarcinoma cells showed that DSCG at a given concentration significantly improved accumulation of HY within cells compared to DMSO (p < 0.05) despite the relative resistance of the HT-29 cell line to HY-PDT. Though no significant difference between total reactive oxygen species production was observed for photoactivated HY dissolved in DMSO and DSCG, significant singlet oxygen generation by photoactivated HY dissolved in a DSCG-containing water solution at the studied molecular ratio was confirmed. We also clarified that DSCG does not act as a scavenger of ABTS and galvinoxyl free radicals. The results from an MTT assay showed that DSCG also significantly enhanced the cytotoxicity of photoactivated HY compared to DMSO (p < 0.05). This study has demonstrated the ability of DSCG to act as a solvent of HY and enhance the effectiveness of HY-PDT compared to the commonly used organic solvent, DMSO.

Physicochemical stability of bioadhesive thermoresponsive platforms for methylene blue and hypericin delivery in photodynamic therapy

Hypericin (Hyp), a natural hydrophobic and photoactive pigment, and methylene blue (MB), a hydrophilic cationic dye, are utilized as photosensitizer (PS) for photodynamic therapy of cancer. Bioadhesive and thermoresponsive polymeric systems can improve the drug availability by increasing the contact time between the system and the mucosa and also controlling the drug release. In this work, an accelerated physicochemical stability study of binary polymeric systems composed of poloxamer 407 (Polox) and Carbopol 934 P (Carb) for MB or Hyp release was performed. Formulations were prepared containing Polox (20%, w/w), Carb (0.15%, w/w) and MB (0.25%, w/w) or Hyp (0.01%, W/W) and submitted to different stress conditions (5 ± 3 °C, 25 ± 2 °C and 40 ± 2 °C with relative humidity of 75 ± 5%) during 180 days. The samples were analyzed as macroscopic characteristics, photosensitizer content and mechanical properties by texture profile analysis. Both systems displayed decrease of photosensitizer content less than 5% during 180 days. MB-system showed an undefined reaction model, while Hyp-system displayed PS decay following a pseudo first-order reaction. Systems also displayed stable mechanical characteristics. The pharmaceutical analyses showed the good physicochemical stability of the bioadhesive platform for delivery Hyp and MB in photodynamic therapy.

The potential of hypericin and hyperforin for antiadhesion therapy to prevent metastasis of parental and oxaliplatin-resistant human adenocarcinoma cells (HT-29)

Cancer cells disseminate to other parts of the body during metastasis through the process of intravasation. The hypericin and hyperforin effect has been described to understand the signal mechanisms that stimulate or stunt cancer cell sprouting to metastasis on colon adenocarcinoma cells HT-29 and its resistant form HT-29-OxR. We focused on the key points of adhesion proteins (cadherin, integrin, selectin and syndecan) and also proteins participating in or contributing to the process of cancer cell migration and adhesion through genes expression and proteins levels. Treatment effects were identified as a consequence of decreased cell adhesion, changes of expression in the adhesive proteins as well as basal membrane degradation associated with changes in the expression of matrix proteinases and in their activity. Finally, the cells affected by hypericin or hyperforin were evaluated by monitoring the cancer cell adhesion properties and proliferation processes. Supplementary Fig. (Supplemental digital content 1, http://links.lww.com/ACD/A267).

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.

5-Fluorouracil-induced mitochondrial oxidative cytotoxicity and apoptosis are increased in MCF-7 human breast cancer cells by TRPV1 channel activation but not Hypericum perforatum treatment

5-Fluorouracil (5-FU) is a widely used chemotherapy agent for breast cancer, although drug resistance is a critical issue regarding the use of this agent in the disease. Calcium signaling is a well-known main cause of proliferation and apoptosis in breast cancer cells. Although previous studies have implicated TRPV1 inhibitor, anticancer, and apoptotic roles of Hypericum perforatum (HPer) in several cells, the synergistic inhibition effects of HPer and 5-FU in cancer and the stimulation of ongoing apoptosis have not yet been clarified in MCF-7 cells. Therefore, we investigated the apoptotic and antioxidant properties of 5-FU with/without HPer through activation of TRPV1 in MCF-7 cells. The MCF-7 cells were divided into four groups: the control group, the HPer-treated group (0.3 mM), the 5-FU-treated group (25 μM), and the 5-FU+HPer-treated group. The intracellular free calcium ion concentration ([Ca²⁺]_i) increased with 5-FU treatments, but they decreased with the HPer and HPer+5-FU treatments. The [Ca²⁺]_i is further decreased in the four groups by TRPV1 channel antagonist (capsazepine and 0.01 mM) treatments. However, mitochondrial membrane depolarization and apoptosis levels, and the PARP1, caspase 3, and caspase 9 expression levels were increased by 5-FU treatment, although the values were decreased by the HPer and 5-FU+HPer treatments. Cell viability level was also decreased by 5-FU treatment. In conclusion, antitumor and apoptosis effects of 5-FU are up-regulated by activation of TRPV1 channels, but its action was down-regulated by HPer treatment. It seems that HPer cannot be used for increasing the antitumor effect of 5-FU through modulation of the TRPV1.

Evaluation of the cytotoxic activity of Hypericum spp. on human glioblastoma A1235 and breast cancer MDA MB-231 cells

Cytotoxic activity of 16 Hypericum ethanolic extracts was evaluated by MTT assay on two human cancer cell lines: glioblastoma A1235 and breast cancer MDA MB-231. Morphology and the type of induced cell death were determined using light and fluorescence microscopy. The majority of Hypericum extracts had no significant cytotoxic effect on MDA MB-231 cells. Eight extracts exhibited mild cytotoxic effect on A1235 cells after 24 h incubation, ranging from 8.0% (H. patulum) to 21.7% (H. oblongifolium). After 72 h of treatment, the strongest inhibition of A1235 viability was observed for extracts of H. androsaemum (26.4-43.9%), H. balearicum (25.8-36.3%), H. delphicum (14.8-27.4%) and H. densiflorum (11.2-24.1%). Micro-scopic examination of cells showed apoptosis as the dominant type of cell death. Due to observed high viability of treated cells, we propose that cytotoxic effects of Hypericum extracts could be related to alternations/interruptions in the cell cycle.

Photodynamic action of palmatine hydrochloride on colon adenocarcinoma HT-29 cells

Palmatine hydrochloride (PaH) is a natural active compound from a traditional Chinese medicine (TCM). The present study aims to evaluate the effect of PaH as a new photosensitizer on colon adenocarcinoma HT-29 cells upon light irradiation. Firstly, the absorption and fluorescence spectra of PaH were measured using a UV-vis spectrophotometer and RF-1500PC spectrophotometer, respectively. Singlet oxygen ((1)O2) production of PaH was determined using 1, 3-diphenylisobenzofuran (DPBF). Dark toxicity of PaH was estimated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cellular uptake of PaH in HT-29 cells was detected at different time intervals. Subellular localization of PaH in HT-29 cells was observed using confocal laser fluorescence microscopy. For photodynamic treatment, HT-29 cells were incubated with PaH and then irradiated by visible light (470nm) from a LED light source. Photocytotoxicity was investigated 24h after photodynamic treatment using MTT assay. Cell apoptosis was observed 18h after photodynamic treatment using a flow cytometry with Annexin V/PI staining. Results showed that PaH has an absorption peak in the visible region from 400nm to 500nm and a fluorescence emission peak at 406nm with an excitation wavelength of 365nm. PaH was activated by the 470nm visible light from a LED light source to produce (1)O2. Dark toxicity showed that PaH alone treatment had no cytotoxicity to HT-29 cancer cells and NIH-3T3 normal cells after incubation for 24h. After incubation for 40min, the cellular uptake of PaH reached to the maximum and PaH was located in mitochondria. Photodynamic treatment of PaH demonstrated a significant photocytotoxicity on HT-29 cells. The rate of cell death increased significantly in a PaH concentration-dependent and light dose-dependent manner. Further evaluation revealed that the early and late apoptotic rate of HT-29 cells increased remarkably up to 21.54% and 5.39% after photodynamic treatment of PaH at the concentration of 5μM and energy density of 10.8J/cm(2). Our findings demonstrated that PaH as a naturally occurring photosensitizer has potential in photodynamic therapy on colon adenocarcinoma.

Does St. John’s Wort cause regression in gastrointestinal system adenocarcinomas?

St. John’s Wort (SJW) is an old herb which has long been consumed widely for its anti-inflammatory, antiviral, and anti-depressive properties. Here we present a detailed clinical evaluation of three cases (two colon and one duodenal adenocarcinoma) with remarkable and intensive lymphoplasmocytic host reaction, at the basal part of tumor, intensive fibrosis, giant cells, plasma cell increase in lymph nodes and few giant cells in germinal centers in resection specimens. The observation of similar host reaction in those tumors having otherwise usual appearance was interesting. None of the cases received neoadjuvant chemoradiotherapy or additional treatment before surgery but only SJW. These cases are presented to increase the awareness about such cases. Further research is needed to reveal the possible effect of SJW, which has long been consumed for different treatment purposes, on human tumors.

Alterations in dysadherin expression and F-actin reorganization: a possible mechanism of hypericin-mediated photodynamic therapy in colon adenocarcinoma cells

Dysadherin is a recently found anti-adhesion molecule, therefore detection and down regulation of its expression is promising in cancer treatment. The up-regulation of dysadherin contributes to colon cancer recurrence and metastasis. Dysadherin also has connections with cytoskeletal proteins and it can cause alterations in the organisation of filamentous actin (F-actin) in metastatic cancers. In this study, hypericin (HYP)-mediated photodynamic therapy (PDT) was performed in two different grade colon adenocarcinoma cell lines HT-29 (Grade I) and Caco-2 (Grade II). Cells were treated with 0.04, 0.08 or 0.15 μM HYP concentrations and irradiated with (4 J/cm(2)) fluorescent lamps. The effects of HYP was examined 16 and 24 h after the activation. We investigated for the first time the effect of HYP-mediated PDT on the expression of dysadherin and F-actin organisation. According to the results, HYP mediated PDT caused a decrease in gene expression and immunofluorescence staining of dysadherin and an increase in actin stress fibers and actin aggregates in HT-29 and Caco-2 cell lines. Besides, cytotoxicity, number of floating cells and apoptotic index changed depending on the cell type, HYP concentration and incubation time. We have demonstrated for the first time that dysadherin and F-actin could be target molecules for HYP-mediated PDT in HT-29 and Caco-2 colon cancer cell lines.

Secondary plant products causing photosensitization in grazing herbivores: their structure, activity and regulation

Photosensitivity in animals is defined as a severe dermatitis that results from a heightened reactivity of skin cells and associated dermal tissues upon their exposure to sunlight, following ingestion or contact with UV reactive secondary plant products. Photosensitivity occurs in animal cells as a reaction that is mediated by a light absorbing molecule, specifically in this case a plant-produced metabolite that is heterocyclic or polyphenolic. In sensitive animals, this reaction is most severe in non-pigmented skin which has the least protection from UV or visible light exposure. Photosensitization in a biological system such as the epidermis is an oxidative or other chemical change in a molecule in response to light-induced excitation of endogenous or exogenously-delivered molecules within the tissue. Photo-oxidation can also occur in the plant itself, resulting in the generation of reactive oxygen species, free radical damage and eventual DNA degradation. Similar cellular changes occur in affected herbivores and are associated with an accumulation of photodynamic molecules in the affected dermal tissues or circulatory system of the herbivore. Recent advances in our ability to identify and detect secondary products at trace levels in the plant and surrounding environment, or in organisms that ingest plants, have provided additional evidence for the role of secondary metabolites in photosensitization of grazing herbivores. This review outlines the role of unique secondary products produced by higher plants in the animal photosensitization process, describes their chemistry and localization in the plant as well as impacts of the environment upon their production, discusses their direct and indirect effects on associated animal systems and presents several examples of well-characterized plant photosensitization in animal systems.

Hypericin-photodynamic therapy leads to interleukin-6 secretion by HepG2 cells and their apoptosis via recruitment of BH3 interacting-domain death agonist and caspases

Photodynamic therapy (PDT) has emerged as a capable therapeutic modality for the treatment of cancer. PDT is a targeted cancer therapy that reportedly leads to tumor cell apoptosis and/or necrosis by facilitating the secretion of certain pro-inflammatory cytokines and expression of multiple apoptotic mediators in the tumor microenvironment. In addition, PDT also triggers oxidative stress that directs tumor cell killing and activation of inflammatory responses. However, the cellular and molecular mechanisms underlying the role of PDT in facilitating tumor cell apoptosis remain ambiguous. Here, we investigated the ability of PDT in association with hypericin (HY) to induce tumor cell apoptosis by facilitating the induction of reactive oxygen species (ROS) and secretion of Th1/Th2/Th17 cytokines in human hepatocellular liver carcinoma cell line (HepG2) cells. To discover if any apoptotic mediators were implicated in the enhancement of cell death of HY-PDT-treated tumor cells, selected gene profiling in response to HY-PDT treatment was implemented. Experimental results showed that interleukin (IL)-6 was significantly increased in all HY-PDT-treated cells, especially in 1 μg/ml HY-PDT, resulting in cell death. In addition, quantitative real-time PCR analysis revealed that the expression of apoptotic genes, such as BH3-interacting-domain death agonist (BID), cytochrome complex (CYT-C) and caspases (CASP3, 6, 7, 8 and 9) was remarkably higher in HY-PDT-treated HepG2 cells than the untreated HepG2 cells, entailing that tumor destruction of immune-mediated cell death occurs only in PDT-treated tumor cells. Hence, we showed that HY-PDT treatment induces apoptosis in HepG2 cells by facilitating cytotoxic ROS, and potentially recruits IL-6 and apoptosis mediators, providing additional hints for the existence of alternative mechanisms of anti-tumor immunity in hepatocellular carcinoma, which contribute to long-term suppression of tumor growth following PDT.

Application of liposomes in drug development--focus on gastroenterological targets

Over the past decade, liposomes became a focal point in developing drug delivery systems. New liposomes, with novel lipid molecules or conjugates, and new formulations opened possibilities for safely and efficiently treating many diseases including cancers. New types of liposomes can prolong circulation time or specifically deliver drugs to therapeutic targets. This article concentrates on current developments in liposome based drug delivery systems for treating diseases of the gastrointestinal tract. We will review different types and uses of liposomes in the development of therapeutics for gastrointestinal diseases including inflammatory bowel diseases and colorectal cancer.