Hypericin and photodynamic therapy decreases human pancreatic cancer in vitro and in vivo

Photobiomodulation and photodynamic therapy-induced switching of autophagy and apoptosis in human dermal fibroblasts

Nowadays, photobiomodulation (PBM) in combination with chemotherapy or other therapeutic approaches is an attractive adjuvant modality for cancer treatment. Targeted destruction of cancer cells is one of the main advantages of photodynamic therapy (PDT). We have shown in previous studies that the combination of PBM at 808 nm and hypericin-mediated PDT increases PDT efficacy in human glioblastoma cells U87 MG. The study presented here shows significant differences between U87 MG and non-cancerous human dermal fibroblasts (HDF) cells treated by PBM and PDT. This study focuses on mitochondria because PBM mainly affects these organelles. We demonstrated that an interplay between mitochondrial and autophagic proteins plays a crucial role in the response of HDF cells to PBM and PDT. Fluorescence microscopy, flow cytometry, and Western blot analysis were used to examine the autophagic profile of HDF cells after these treatments. An increase in ubiquitin, SQSTM1, LC3BII, and cytochrome c was accompanied by a decrease in M6PR, ATG16L1, and Opa1 in HDF cells exposed to PBM and PDT. Overall, we observed that the switching of autophagy and apoptosis is dose-dependent and also occurs independently of PBM in HDF cells after hypericin-mediated PDT. However, PBM might preferentially induce autophagy in noncancer cells, which might escape apoptosis under certain conditions.

Some Natural Photosensitizers and Their Medicinal Properties for Use in Photodynamic Therapy

Despite significant advances in early diagnosis and treatment, cancer is one of the leading causes of death. Photodynamic therapy (PDT) is a therapy for the treatment of many diseases, including cancer. This therapy uses a combination of a photosensitizer (PS), light irradiation of appropriate length and molecular oxygen. The photodynamic effect kills cancer cells through apoptosis, necrosis, or autophagy of tumor cells. PDT is a promising approach for eliminating various cancers but is not yet as widely applied in therapy as conventional chemotherapy. Currently, natural compounds with photosensitizing properties are being discovered and identified. A reduced toxicity to healthy tissues and a lower incidence of side effects inspires scientists to seek natural PS for PDT. In this review, several groups of compounds with photoactive properties are presented. The use of natural products has been shown to be a fruitful approach in the discovery of novel pharmaceuticals. This review focused on the anticancer activity of furanocoumarins, polyacetylenes, thiophenes, tolyporphins, curcumins, alkaloid and anthraquinones in relation to the light-absorbing properties. Attention will be paid to their phototoxic and anti-cancer effects on various types of cancer.

Monitoring tautomerization of single hypericin molecules in a tunable optical λ/2 microcavity

Hypericin tautomerization that involves the migration of the labile protons is believed to be the primary photophysical process relevant to its light-activated antiviral activity. Despite the difficulty in isolating individual tautomers, it can be directly observed in single-molecule experiments. We show that the tautomerization of single hypericin molecules in free space is observed as an abrupt flipping of the image pattern accompanied with fluorescence intensity fluctuations, which are not correlated with lifetime changes. Moreover, the study can be extended to a λ/2 Fabry-Pérot microcavity. The modification of the local photonic environment by a microcavity is well simulated with a theoretical model that shows good agreement with the experimental data. Inside a microcavity, the excited state lifetime and fluorescence intensity of single hypericin molecules are correlated, and a distinct jump of the lifetime and fluorescence intensity reveals the temporal behavior of the tautomerization with high sensitivity and high temporal resolution. The observed changes are also consistent with time-dependent density functional theory calculations. Our approach paves the way to monitor and even control reactions for a wider range of molecules at the single molecule level.

Hypericin-loaded oil-in-water nanoemulsion synthesized by ultrasonication process enhances photodynamic therapy efficiency

Hypericin (Hy) is a hydrophobic photosensitizer used in photodynamic therapy for cancer therapeutic. In this study, Hy-loaded oil-in-water (O/W) nanoemulsions (NEs) were produced by the ultrasonication method combing different biocompatible oils and surfactants to enhance Hy aqueous solubility and bioavailability. Experimental parameters were optimized by the characterization of droplet size, zeta potential, and physicochemical properties. In vitro studies based on the release profile, cytotoxicity, cell morphology, and Hy intracellular accumulation were assayed. Hy at 100 mg L^-1 was incorporated into the low viscosity (~0.005 Pa s) NEs with spherical droplets averaging 20-40 nm in size and polydispersity index <0.02. Hy release from the NE was significantly higher (4-fold) than its suspension (p < 0.001). The NEs demonstrated good physical stability during storage at 5 °C for at least six months. The Hy-loaded NEs exhibited an IC50 value 6-fold lower than Hy suspension during PDT against breast cancer cell lines (MCF-7). Cell microscopy imaging confirmed the increased cytotoxic effects of Hy-loaded NEs, showing damaged and apoptotic cells. Confocal laser scanning microscopy evidenced greater Hy delivery through NE into MCF-7 cells followed by improved intracellular ROS generation. Our results suggest that the Hy-loaded NEs can improve hypericin efficacy and assist Hy-PDT's preclinical development as a cancer treatment.

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.

St. John's Wort Suppresses Growth in Triple-Negative Breast Cancer Cell Line MDA-MB-231 by Inducing Prodeath Autophagy and Apoptosis

The rational regulation of programmed cell death by means of autophagy and apoptosis has been considered a potential treatment strategy for cancer. We demonstrated the inhibitory effect of St. John’s Wort (SJW) on growth in the triple-negative breast cancer (TNBC) cell line and xenografted mice and its target mechanism concerning autophagic and apoptotic cell death. SJW ethanol extract (SJWE) inhibited proliferation in a dose-dependent manner. SJWE treatment dramatically increased autophagy flux and apoptosis compared with the control. The autophagy inhibitor, 3-methyladenine (3-MA), reversed the SJWE-induced inhibition of cell proliferation and regulation of autophagy and apoptosis, indicating that SJWE induced apoptosis through prodeath autophagy. Furthermore, SJWE inhibited tumor growth and induced autophagy and apoptosis in the tumor of MDA-MB-231 xenografted athymic nude mice. Our results indicate that SJWE might have great potential as a new anticancer therapy for triple-negative breast cancer by inducing prodeath autophagy and apoptosis.

Radiolabeling, In Vitro Cell Uptake, and In Vivo Photodynamic Therapy Potential of Targeted Mesoporous Silica Nanoparticles Containing Zinc Phthalocyanine

Photodynamic therapy (PDT) is a noninvasive therapy based on the photodynamic effect. In this study, we sought to determine intracellular uptake and in vivo photodynamic therapy potential of Zn phthalocyanine-loaded mesoporous silica nanoparticles (MSNP5) against pancreatic cancer cells. MSNP5 were labeled with ¹³¹I; the radiolabeling efficiency was found to 95.5 ± 1.2% in pH 9 and 60 min reaction time. Besides, the highest intracellular uptake yields of ¹³¹I-MSNP5 nanoparticles in MIA PaCa-2, AsPC-1, and PANC-1 cells were determined as 43.9 ± 3.8%, 41.8 ± 0.2%, and 37.9 ± 1.3%, respectively, at 24 h incubation time. In vivo PDT studies were performed with subcutaneous xenograft cancer model nude mice with AsPC-1 pancreatic cancer cells. For photodynamic therapy, 685 nm red laser light 100 J/cm² light dose using and 5-20 μM ZnPc containing MSNP5 concentrations were applied. Histopathological studies revealed that the ratio of necrosis in tumor tissue was higher in the treatment group than the control groups.

Anthraquinone: a promising scaffold for the discovery and development of therapeutic agents in cancer therapy

Cancer, characterized by uncontrolled malignant neoplasm, is a leading cause of death in both advanced and emerging countries. Although, ample drugs are accessible in the market to intervene with tumor progression, none are totally effective and safe. Natural anthraquinone (AQ) equivalents such as emodin, aloe-emodin, alchemix and many synthetic analogs extend their antitumor activity on different targets including telomerase, topoisomerases, kinases, matrix metalloproteinases, DNA and different phases of cell lines. Nano drug delivery strategies are advanced tools which deliver drugs into tumor cells with minimum drug leakage to normal cells. This review delineates the way AQ derivatives are binding on these targets by abolishing tumor cells to produce anticancer activity and purview of nanoformulations related to AQ analogs.

Phyotochemical candidates repurposing for cancer therapy and their molecular mechanisms

Though limited success through chemotherapy, radiotherapy and surgery has been obtained for efficient cancer therapy for modern decades, cancers are still considered high burden to human health worldwide to date. Recently repurposing drugs are attractive with lower cost and shorter time compared to classical drug discovery, just as Metformin from Galega officinalis, originally approved for treating Type 2 diabetes by FDA, is globally valued at millions of US dollars for cancer therapy. As most previous reviews focused on FDA approved drugs and synthetic agents, current review discussed the anticancer potential of phytochemicals originally approved for treatment of cardiovascular diseases, diabetes, infectious diarrhea, depression and malaria with their molecular mechanisms and efficacies and suggested future research perspectives.

Verteporfin- and sodium porfimer-mediated photodynamic therapy enhances pancreatic cancer cell death without activating stromal cells in the microenvironment

The goal of our study was to determine the susceptibility of different pancreatic cell lines to clinically applicable photodynamic therapy (PDT). The efficacy of PDT of two different commercially available photosensitizers, verteporfin and sodium porfimer, was compared using a panel of four different pancreatic cancer cell lines, PANC-1, BxPC-3, CAPAN-2, and MIA PaCa-2, and an immortalized non-neoplastic pancreatic ductal epithelium cell line, HPNE. The minimum effective concentrations and dose-dependent curves of verteporfin and sodium porfimer on PANC-1 were determined. Since pancreatic cancer is known to have significant stromal components, the effect of PDT on stromal cells was also assessed. To mimic tumor-stroma interaction, a co-culture of primary human fibroblasts or human pancreatic stellate cell (HPSCs) line with PANC-1 was used to test verteporfin-PDT-mediated cell death of PANC-1. Two cytokines (TNF-α and IL-1β) were used for stimulation of primary fibroblasts (derived from human esophageal biopsies) or HPSCs. The increased expression of smooth muscle actin (α-SMA) confirmed the activation of fibroblasts or HPSC upon treatment with TNF-α and IL-1β. Cell death assays showed that both sodium porfimer- and verteporfin-mediated PDT-induced cell death in a dose-dependent manner. However, verteporfin-PDT treatment had a greater efficiency with 60  ×   lower concentration than sodium porfimer-PDT in the PANC-1 incubated with stimulated fibroblasts or HPSC. Moreover, activation of stromal cells did not affect the treatment of the pancreatic cancer cell lines, suggesting that the effects of PDT are independent of the inflammatory microenvironment found in this two-dimensional culture model of cancers.

Phase 1 study of EUS-guided photodynamic therapy for locally advanced pancreatic cancer

BACKGROUND AND AIMS

Locally advanced pancreatic cancer (LAPC) has a poor prognosis. There are limited data describing the use of photodynamic therapy (PDT) for pancreatic cancer in humans. We hypothesized that EUS-guided PDT for LAPC is safe, technically feasible, and produces a dose- and time-dependent increasing degree of image-defined tumor necrosis.

METHODS

In a single-center, prospective, dose-escalation phase 1 study, patients with treatment-naïve LAPC received intravenous porfimer sodium (Concordia Laboratories Inc, St Michael, Barbados) followed 2 days later by EUS-PDT. EUS-PDT was performed by puncture with a 19-gauge needle and insertion of a 1.0-cm light diffuser (Pioneer Optics, Bloomfield, Conn) and illumination with a 630-nm light (Diomed Inc, Andover, Mass). A CT scan 18 days after PDT was done to assess for change in pancreatic necrosis. Nab-paclitaxel (125 mg/ m² intravenously) and gemcitabine (1000 mg /m² intravenously) were initiated 7 days after CT and given weekly for 3 of 4 weeks (1 cycle) until disease progression or unacceptable toxicity.

RESULTS

Twelve patients (mean age, 67 ± 6 years; 8 male) with tumors (mean diameter, 45.2 ± 12.9 mm) in the head and/or neck (8) or body and/or tail (4) underwent EUS-PDT. Compared with baseline imaging, increased volume and percentage of tumor necrosis were observed in 6 of 12 patients (50%) after EUS-PDT. The mean overall increases in volume and percentage necrosis were 10 ± 26 cm³ (P = .20) and 18% ± 22% (P = .016), respectively. After a median follow-up of 10.5 months (range, 1.0-37.4 months), median progression-free (PFS) and overall survival (OS) were 2.6 months (95% confidence interval, 0.7, not estimable) and 11.5 months (95% confidence interval, 1.1, 16.9), respectively. Surgical resection was attempted in 2 patients, and pathology showed a complete response (n = 1) and residual 2-mm tumor (n = 1). There were 8 serious adverse events and none related to EUS or EUS-PDT.

CONCLUSION

EUS-PDT for LAPC appears to be safe and produces measurable imaged-defined tumor necrosis. Phase 2 studies are warranted. (Clinical trial registration number: NCT01770132.).

Distribution of total phenols, flavonoids and hypericin in different plant organs of wild-growing St. John’s-wort (Hypericum perforatum L., Hypericaceae) from North Macedonia

Hypericum perforatum L. (Hypericaceae) contains secondary metabolites that show noteworthy pharmacological activities. Therefore, the content of total phenols, flavonoids and hypericin from whole herb, flowers and leafs from St. John’s-wort collected over four consecutive seasons (2014-2017) from three different locations in western part of North Macedonia (Tetovo, Debar and Mavrovo) were investigated by three different spectrophotometric methods (using Folin-Ciocalteu reagent, NaNO2-AlCl3-NaOH and mixture of water/tetrahydrofuran). The quantity of total phenols obtained from different plant organs (leafs, whole herb and flowers) were 35.15-83.08 mg GAE/g, 55.41-98.52 mg GAE/g and 75.44-121.19 mg GAE/g, respectively. Afterword the total flavonoids contents were: 61.64-106.86 mg CE/g, 73.04-117.57 mg CE/g and 108.65-125.35 mg CE/g in leafs, whole herb and flowers, respectively, while the hypericin amounts were: 0.03-0.17 mg/g, 0.04-0.29 mg/g and 0.07-0.60 mg/g in leafs, whole herb, and flowers, respectively. Significant differences were observed in the quantities of total phenols, flavonoids and hypericin between the locations of harvesting, while the collection seasons were found not to be significant. Additionally, it can be seen that the flowers are characterized by higher amounts of total phenols, total flavonoids and hypericin compared to total herb and leaf in all three locations, therefore harvesting of St. John’s-wort should be made in a manner of obtaining larger quantities of flowers as harvesting material which could increase the bioactive compounds in the herbal row material. Keywords: Hypericum perforatum, plant organs, total phenols, flavonoids, hypericin, statistical analysis

Hypericin-assisted photodynamic therapy against anaplastic thyroid cancer

BACKGROUND

Hypericin (HYP) extracted from St. John's wort (Hypericum perforatum L.) is a natural photosensitizer in clinical photodynamic therapy (PDT). PDT is one of the powerful methods for cancer treatments because of its excellent tumoritropic characteristics and photosensitizing properties. However, limited reports on the efficacy of PDT on anaplastic thyroid cancer (ATC) have been published. Especially HYP-associated PDT has not been investigated in vitro and in vivo. In this study, we evaluated the effect of HYP for PDT against FRO ATC cells.

METHODS

The activities of HYP-assisted PDT were investigated in ATC cells. The ATC FRO cells were treated with a combination of HYP dose and laser power. The viability of FRO cells was measured by MTT assay, and Trypan blue staining was performed to monitor cell death. Detection reactive oxygen species (ROS) and mitochondrial membrane potential after HYP-assisted PDT were analyzed by confocal microscopy. For in vivo study, FRO cells were injected into nude mice. After intravenous injection of HYP, Laser was irradiated and nude mice were monitored in Day 4, 7, 14.

RESULTS AND CONCLUSIONS

The rate of FRO cell death was increased by applying HYP dose and laser power dependent. Moreover, HYP and laser irradiation induced FRO cell death was mediated by the intracellular ROS generation and mitochondrial damage. Finally, the HYP-assisted PDT eliminated FRO cell tumor from the mouse in vivo. These data demonstrate that HYP could be an effective photosensitizer for human ATC therapy.

St. John's Wort Regulates Proliferation and Apoptosis in MCF-7 Human Breast Cancer Cells by Inhibiting AMPK/mTOR and Activating the Mitochondrial Pathway

St. John’s Wort (SJW) has been used as an estrogen agonist in the systems affected by menopause. Also, hypericin, a bioactive compound of SJW, has been used as a photosensitizer in photodynamic therapy. In the present study, we investigate the anti-proliferative and pro-apoptotic effects of SJW to demonstrate the chemo-preventive effect in human breast cancer cells. MCF-7 cells were cultured with DMSO or various concentrations of SJW ethanol extract (SJWE). Cell viability, proliferation, apoptosis, the expression of proteins involved in cell growth and apoptosis, and caspase-3/7 activity were examined. SJWE dose-dependently suppressed cell growth and induced apoptosis of MCF-7 cells. Mechanistically, SJWE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and decreased the expression of p-mammalian target of rapamycin (p-mTOR) and p-eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). Also, SJWE inhibited the phosphorylation of protein kinase B (Akt) and showed increases in the expression of pro-apoptotic proteins Bax and Bad with decreases in the expression of anti-apoptotic proteins including B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), and p-Bcl-2-associated death promoter (p-Bad). SJWE at 50 μg/mL showed markedly enhanced caspase-7 activation. Taken together, our results provide evidence that SJWE shows anti-proliferative and pro-apoptotic effects via inhibition of AMPK/mTOR and activation of a mitochondrial pathway. Therefore, SJWE can be used as a chemo-preventive agent without photo-activation.

Scutellarin inhibits RANKL-mediated osteoclastogenesis and titanium particle-induced osteolysis via suppression of NF-κB and MAPK signaling pathway

Aseptic prosthetic loosening is a major complication after hip joint replacement. Wear particle-induced periprosthetic osteolysis plays a key role in aseptic prosthetic loosening. Attempting to modulate receptor activator of nuclear factor-κB (RANKL) mediated signaling pathways is a promising strategy to prevent aseptic prosthetic loosening. In the present study, we determined the effect of scutellarin (SCU) on titanium (Ti) particle-induced osteolysis in a mouse calvarial model and RANKL-mediated osteoclastogenesis. We determined that SCU, the major effective constituent of breviscapine isolated from a Chinese herb, has potential effects on preventing Ti particle-caused osteolysis in calvarial model of mouse. In vitro, SCU could suppress RANKL-mediated osteoclastogenesis, the function of osteoclast bone resorption, and the expression levels of osteoclast-specific genes (tartrate-resistant acid phosphatase (TRAP), cathepsin K, c-Fos, NFATc1). Further investigation indicated that SCU could inhibit RANKL-mediated MAPK and NF-κB signaling pathway, including JNK1/2, p38, ERK1/2, and IκBα phosphorylation. Taken together, these results indicate that SCU could inhibit osteoclastogenesis and prevent Ti particle-induced osteolysis by suppressing RANKL-mediated MAPK and NF-κB signaling pathway. These results suggest that SCU is a promising therapeutic agent for preventing wear particle-induced periprosthetic osteolysis.

Hypericin in the Light and in the Dark: Two Sides of the Same Coin

Hypericin (4,5,7,4',5',7'-hexahydroxy-2,2'-dimethylnaphtodianthrone) is a naturally occurring chromophore found in some species of the genus Hypericum, especially Hypericum perforatum L. (St. John's wort), and in some basidiomycetes (Dermocybe spp.) or endophytic fungi (Thielavia subthermophila). In recent decades, hypericin has been intensively studied for its broad pharmacological spectrum. Among its antidepressant and light-dependent antiviral actions, hypericin is a powerful natural photosensitizer that is applicable in the photodynamic therapy (PDT) of various oncological diseases. As the accumulation of hypericin is significantly higher in neoplastic tissue than in normal tissue, it can be used in photodynamic diagnosis (PDD) as an effective fluorescence marker for tumor detection and visualization. In addition, light-activated hypericin acts as a strong pro-oxidant agent with antineoplastic and antiangiogenic properties, since it effectively induces the apoptosis, necrosis or autophagy of cancer cells. Moreover, a strong affinity of hypericin for necrotic tissue was discovered. Thus, hypericin and its radiolabeled derivatives have been recently investigated as potential biomarkers for the non-invasive targeting of tissue necrosis in numerous disorders, including solid tumors. On the other hand, several light-independent actions of hypericin have also been described, even though its effects in the dark have not been studied as intensively as those of photoactivated hypericin. Various experimental studies have revealed no cytotoxicity of hypericin in the dark; however, it can serve as a potential antimetastatic and antiangiogenic agent. On the contrary, hypericin can induce the expression of some ABC transporters, which are often associated with the multidrug resistance (MDR) of cancer cells. Moreover, the hypericin-mediated attenuation of the cytotoxicity of some chemotherapeutics was revealed. Therefore, hypericin might represent another St. John's wort metabolite that is potentially responsible for negative herb-drug interactions. The main aim of this review is to summarize the benefits of photoactivated and non-activated hypericin, mainly in preclinical and clinical applications, and to uncover the "dark side" of this secondary metabolite, focusing on MDR mechanisms.

Photoactivation of hypericin decreases the viability of RINm5F insulinoma cells through reduction in JNK/ERK phosphorylation and elevation of caspase-9/caspase-3 cleavage and Bax-to-Bcl-2 ratio

Insulinomas cause neuroglycopenic symptoms, permanent neurological damage and even death. Current available therapies cannot satisfactorily treat malignant insulinomas and some benign insulinomas. The promising phototherapeutic results and harmless side effects of hypericin in some cancer treatments prompted us to explore possible anti-growth activity of photoactivated hypericin against RINm5F insulinoma cells and underlying mechanisms. We now show that detectable and maximal internalization of hypericin in RINm5F insulinoma cells occurred in 20 and 60 min respectively. Hypericin was considerably associated with the plasma membrane, appreciably localized in the sub-plasma membrane region and substantially accumulated in the cytoplasm. Photoactivated hypericin decreased the viability of RINm5F insulinoma cells due to its anti-proliferative and apoptotic actions. Photoactivation of hypericin inhibited cell proliferation reflected by decreased expression of the proliferation marker Ki-67 and cell-cycle arrest in the G₀/G₁-phase. The anti-proliferative effect resulted from down-regulation of phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular-signal-regulated kinase (ERK). Photoactivated hypericin triggered apoptosis through activation of caspase-3 and caspase-9 and elevation of the Bax-to B-cell lymphoma 2 (Bcl-2) ratio. The findings lay a solid foundation for implementation of hypericin-mediated photodynamic therapy in treatment of insulinomas.

Photoexcited hypericin exerts strong antigrowth activity in RINm5F insulinoma cells via inhibition of cell proliferation by reducing JNK/ERK phosphorylation and stimulation of apoptosis by elevating caspase-9/caspase-3 cleavage and Bax-to-Bcl-2 ratio.

Hypericin-mediated photodynamic therapy induces apoptosis of myoloma SP2/0 cells depended on caspase activity in vitro

BACKGROUND

Photodynamic therapy (PDT) is becoming a promising therapeutic modality for hematological malignancies. Hypericin is a natural photosensitizer possessing anti-depressant, anti-virus and anti-cancer activities. The present study was designed to explore the effect and mechanism of hypericin-mediated PDT on the mouse multiple myeloma (MM) cells in vitro.

METHODS

The mouse myeloma SP2/0 cells were incubed with different concentrations of hypericin and then illuminated with different light doses. The inhibitory effect of hypericin-mediated PDT on tumor cell proliferation was assayed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method. The apoptosis related morphological changes of SP2/0 cells were observed by microscopy. The biochemical hallmarks of apoptosis such as DNA fragments, mitochondrial membrane potential changes were assessed. The expression of apoptosis related proteins were investigated by western blotting.

RESULTS

Hypericin-mediated PDT induced the proliferation inhibition and apoptosis of tumor cells in a dose dependent manner. Tumor cells showed obvious morphological changes of apoptosis and necrosis and DNA fragmentation after treated by hypericin mediated PDT (0.025 ~ 0.05 μM). The mitochondria membrane potential in SP2/0 cells was decreased significantly after incubated with the 0.025 μM and 0.5 μM hypericin (P < 0.05). The expression level of caspase-3 was decreased, while caspase activity was elevated with the increasing drug dosage. The apoptosis of SP2/0 cells was blocked by a pan-caspase inhibitor Z-VAD-FMK and caspase-3 inhibitor Ac-DEVD-CHO.

CONCLUSION

Hypericin-mediated PDT induced apoptosis mainly dependent on caspase related pathways. Hypericin-mediated PDT may be a potential and alternative therapy for MM.

Hypericin suppresses osteoclast formation and wear particle-induced osteolysis via modulating ERK signalling pathway

Osteoclast-induced bone resorption and wear-particle-induced osteolysis leads to prosthetic loosening, one of the most common causes of joint implant failure, resulting in revision surgery. Thus, inhibition of osteoclastic bone resorption, which further prevents wear particle-induced osteolysis, is a potential treatment strategy for prosthetic loosening. Here, we examined the therapeutic effect of hypericin (HP), which was photosensitive, on osteoclastogenesis and wear particle-induced osteolysis in the absence of visible light. HP inhibited RANKL-induced osteoclast differentiation in bone marrow macrophages (BMMs) and RAW264.7 cell line without any evidence of cytotoxicity. The bone-resorbing activity of mature osteoclasts was significantly inhibited by HP. As HP has been previously reported to inhibit signalling pathway such as ERK and NF-κB in other cells, which is also important in osteoclast differentiation. We thus examined the molecular mechanism and showed that HP significantly inhibited the ERK/mitogen-activated protein kinase (MAPK) signalling pathway without affecting nuclear factor kappaB (NF-κB), c-Jun N-terminal kinase (JNK) and p38 signalling in RANKL-stimulated BMMs. Further in vivo studies revealed HP attenuated osteoclast formation and subsequently prevented wear particle-induced bone erosion. Taken together, the results suggest that HP inhibits RANKL-mediated osteoclastogenesis via affecting ERK signalling in vitro and suppresses wear particle-induced osteolysis in vivo. We therefore conclude that HP may be an innovative and safe alternative treatment for osteoclast-related prosthetic loosening.

Pancreatic cancer-associated Cathepsin E as a drug activator

Pancreatic ductal adenocarcinoma (PDAC) is challenging to treat, and better means to detect and/or treat pancreatic cancer are urgently needed to save lives. Cathepsin E (Cath E) is a proteolytic enzyme highly expressed in PDAC. In this study, a novel approach using Cath E activation of a Cath E-specific prodrug was demonstrated. Specific activation of the prodrug is expected to kill pancreatic cancer cells without harming normal pancreatic cells. A novel 5-aminolevulinic acid (5-ALA) prodrug was custom-designed to be activated selectively by endogenous Cath E within the PDAC cells. The 5-ALA prodrug was incubated with Cath E-positive and -negative tumor cells and illuminated with various doses of light. In addition, mice genetically engineered to develop PDAC were injected intravenously with the 5-ALA prodrug, and the pancreas was treated with light irradiation. One day after treatment, PDAC tissue was assessed for apoptosis. The 5-ALA prodrug was activated within the Cath E-positive tumor but not in the normal pancreatic tissue. When used in combination with light treatment, it allowed delivery of selective photodynamic therapy (PDT) to the cancerous tissues, with minimal harm to the adjacent normal tissues. With this novel Cath E activation approach, it is possible to detect pancreatic cancer cells accurately and specifically impair their viability, while sparing normal cells. This treatment could result in fewer side effects than the non-specific treatments currently in use. Cath E is a specific and effective drug activator for PDAC treatment.

Effect of Photofrin-mediated photocytotoxicity on a panel of human pancreatic cancer cells

BACKGROUND AND OBJECTIVE

Pancreatic cancer is a leading cause of cancer-related deaths in men and women. Early clinical studies suggest that photodynamic therapy (PDT) might be a useful modality in the management of this deadly disease. In this study, the photocytotoxicity of Photofrin-mediated PDT on different human pancreatic cancer cells (BxPc-3, HPAF-II, Mia PaCa-2, MPanc-96, PANC-1 and PL-45) was examined.

MATERIALS AND METHODS

After co-incubating cancer cells with Photofrin (0-10 μg/ml) for 4h, the cells were irradiated with 0-6J/cm(2) of 630 nm light. The effect of Photofrin PDT on the survival of cells were examined using tetrazolium-based colorimetric assay and clonogenic assay. PDT-induced apoptosis was analyzed by flow cytometry. Expressions of apoptosis-related proteins were determined by western blot analysis.

RESULTS

Photofrin PDT strongly inhibited the survival of pancreatic cancer cells. A small portion of cells (<15%) underwent apoptosis 24h after PDT at LD50. Cleavage of caspase-3, caspase-8, caspase-9 and PARP after PDT were also confirmed. BxPc-3, Mia PaCa-2, MPanc-96, and PANC-1 cells were more sensitive and HPAF-II and PL-45 cells less sensitive.

CONCLUSION

Photofrin PDT can induce apoptosis and inhibit survival of human pancreatic cancer cells.

Identifying the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) as a potential target for hypericin--a theoretical study

The exact cellular target for the potent anti-cancer agent hypericin has not yet been determined; this thus encourages the application of computational chemistry tools to be employed in order to provide insights that can be employed in further drug development studies. In the present study computational docking and molecular dynamics simulations are applied to investigate possible interactions between hypericin and the Ca(2+) pump SERCA as proposed in the literature. Hypericin was found to bind strongly both in pockets within the transmembrane region and in the cytosolic region of the protein, although the two studied isoforms of SERCA differ slightly in their preferred binding sites. The calculated binding energies for hypericin in the four investigated sites were of the same magnitude as for thapsigargin (TG), the most potent SERCA inhibitor, or in the range between TG and di-tert-butylhydroquinone (BHQ), which is also known to possess inhibitory activity. The hydrophobic character of hypericin indicates that the molecule initially binds in the ER membrane from which it diffuses into the transmembrane region of the protein and to binding pockets therein. The transmembrane TG and BHQ binding pockets provide suitable locations for hypericin as they allow for favourable interactions with the lipid tails that surround these. High binding energies were noted for hypericin in these pockets and are expected to constitute highly possible binding sites due to their accessibility from the ER membrane. Hypericin most likely binds to both isoforms of SERCA and acts as an inhibitor or, under light irradiation, as a singlet oxygen generator that in turn degrades the protein or induces lipid peroxidation.

Isolation and purification of series bioactive components from Hypericum perforatum L. by counter-current chromatography

Counter-current chromatography (CCC) combined with pre-separation by ultrasonic solvent extraction was successively used for the separation of series bioactive compounds from the crude extract of Hypericum perforatum L. The petroleum ether extract was separated by the solvent system of n-heptane-methanol-acetonitrile (1.5:0.5:0.5, v/v) and n-heptane-methanol (1.5:1, v/v) in gradient elution, yielding a phloroglucinol compound, hyperforin with HPLC purity over 98%. The ethyl acetate extract was separated by using the solvent system composed of hexane-ethyl acetate-methanol-water (1:1:1:1 and 1:3:1:3, v/v) in gradient through both reverse phase and normal phase elution mode, yielding a naphthodianthrone compound, hypericin with HPLC purity about 95%. The n-butanol extract was separated with the solvent system composed of n-butanol-ethyl acetate-water (1:4:5 and 1.5:3.5:5, v/v) in elution and back-extrusion mode, yielding two of flavones, rutin and hyperoside, with HPLC purity over 95%. HPLC-MS, reference sample and UV spectrum were selectively used in separation to search for target compounds from HPLC-DAD profiles of different sub-extracts. The structures of isolated compounds were further identified by ESI-MS, ¹HNMR and ¹³CNMR.

Combating melanoma: the use of photodynamic therapy as a novel, adjuvant therapeutic tool

Metastatic malignant melanoma remains one of the most dreaded skin cancers worldwide. Numerous factors contribute to its resistance to hosts of treatment regimes and despite significant scientific advances over the last decade in the field of chemotherapeutics and melanocytic targets, there still remains the need for improved therapeutic modalities. Photodynamic therapy, a minimally invasive therapeutic modality has been shown to be effective in a number of oncologic and non-oncologic conditions. Using second-generation stable, lipophilic photosensitizers with optimised wavelengths, PDT may be a promising tool for adjuvant therapy in combating melanoma. Potential targets for PDT in melanoma eradication include cell proliferation inhibition, activation of cell death and reduction in pro-survival autophagy and a decrease in the cellular melanocytic antioxidant system. This review highlights the current knowledge with respect to these characteristics and suggests that PDT be considered as a good candidate for adjuvant treatment in post-resected malignant metastatic melanoma. Furthermore, it suggests that primary consideration must be given to organelle-specific destruction in melanoma specifically targeting the melanosomes - the one organelle that is specific to cells of the melanocytic lineage that houses the toxic compound, melanin. We believe that using this combined knowledge may eventually lead to an effective therapeutic tool to combat this highly intractable disease.

Benefits of nanoencapsulation for the hypercin-mediated photodetection of ovarian micrometastases

The high recurrence and lethality of ovarian cancer at advanced stages is problematic, especially due to the development of numerous micrometastases scattered throughout the abdominal cavity. Fluorescence photodetection (PD) used in combination with surgical resection of malignant tissues has been suggested to improve recovery. Based on promising in vivo results for the detection of bladder cancer, hypericin (Hy), a natural photosensitizer (PS), stands as a good candidate for the photodetection of ovarian cancer. However, due to its hydrophobicity, systemic administration of Hy is problematic. Polymeric nanoparticles (NPs) help to overcome these delivery and stability problems and enable intravenous administration of Hy. In this study, Hy-loaded NPs of polylactic acid were produced with the following properties: (i) mean size of 268 nm, (ii) negative zeta potential, (iii) low residual surfactant and (iv) drug loading of 3.7 % (w/w). The potential of hypericin-loaded nanoparticles for the fluorescence photodetection of ovarian metastases in Fischer 344 rats bearing ovarian tumours was compared to free drug. The selectivity of Hy administered with both formulations was assessed first by fluorescence endoscopy, and then quantified after tissue extraction. The results showed an improved selective accumulation of Hy in ovarian micrometastases when NPs were used.

Photodynamic therapy for pancreatic cancer

OBJECTIVES

This study examined the status of photodynamic therapy (PDT) in the treatment of cancers of the pancreas.

METHODS

Original and review articles, editorials, and case reports published primarily in English and listed in Medline/ISI up to October 2006 or identified by a manual search have been reviewed in an attempt to provide a comprehensive overview of the mechanisms of PDT action and clinical application of PDT in the treatment of pancreatic cancers.

RESULTS

Photodynamic therapy represents a novel treatment of pancreatic malignancy; it produces local necrosis of tissue with light after administration of a photosensitizing agent. Evidences from in vivo and in vitro results have shown that PDT significantly decreases pancreatic cancer cell growth, destroys pancreatic carcinoma, and prolongs the survival of patients with unresectable pancreatic malignancy, and also show that PDT has disadvantages and limitations for the treatment of pancreatic cancer.

CONCLUSIONS

Photodynamic therapy can be an effective treatment of patients with pancreatic cancer, but more extensive preclinical and clinical trials are needed for further improvement in the clinical application of PDT, especially in avoidance of complications during PDT.

Photodynamic therapy and tumor imaging of hypericin-treated squamous cell carcinoma

Background

Conventional cancer therapy including surgery, radiation, and chemotherapy often are physically debilitating and largely ineffective in previously treated patients with recurrent head and neck squamous cell carcinoma (SCC). A natural photochemical, hypericin, could be a less invasive method for laser photodynamic therapy (PDT) of these recurrent head and neck malignancies. Hypericin has powerful photo-oxidizing ability, tumor localization properties, and fluorescent imaging capabilities as well as minimal dark toxicity. The current study defined hypericin PDT in vitro with human SCC cells before the cells were grown as tumor transplants in nude mice and tested as a model for hypericin induced tumor fluorescence and PDT via laser fiberoptics.

Methods

SNU squamous carcinoma cells were grown in tissue culture, detached from monolayers with trypsin, and incubated with 0.1 μg to 10 μg/ml of hypericin before exposure to laser light at 514, 550, or 593 nm to define optimal dose, time, and wavelength for PDT of tumor cells. The SCC cells also were injected subcutaneously in nude mice and grown for 6–8 weeks to form tumors before hypericin injection and insertion of fiberoptics from a KTP532 surgical laser to assess the feasibility of this operating room instrument in stimulating fluorescence and PDT of tumors.

Results

In vitro testing revealed a hypericin dose of 0.2–0.5 μg/ml was needed for PDT of the SCC cells with an optimal tumoricidal response seen at the 593 nm light absorption maximum. In vivo tumor retention of injected hypericin was seen for 7 to10 days using KTP532 laser induced fluorescence and biweekly PDT via laser fiberoptics led to regression of SCC tumor transplants under 0.4 cm² diameter, but resulted in progression of larger size tumors in the nude mice.

Conclusion

In this preclinical study, hypericin was tested for 514–593 nm dye laser PDT of human SCC cells in vitro and for KTP532 surgical laser targeting of SCC tumors in mice. The results suggest hypericin is a potent tumor imaging agent using this surgical laser that may prove useful in defining tumor margins and possibly in sterilizing post-resection margins. Deeply penetrating pulsed infrared laser emissions will be needed for PDT of larger and more inaccessible tumors.

Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer

A photodynamic approach has been suggested to improve diagnosis and therapy of ovarian cancer. As Hypericin (Hy), a natural photosensitizer (PS) extracted from Hypericum perforatum, has been shown to be efficient in vitro and in vivo for the detection or treatment of other cancers, Hy could also be a potent tool for the treatment and detection of ovarian cancer. Due to its hydrophobicity, systemic administration of Hy is problematic. Thus, polymeric nanoparticles (NPs) of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA) were used as a drug delivery system. Hy-loaded NPs were produced with the following characteristics: (i) size in the 200-300 nm range, (ii) negative zeta potential, (iii) low residual PVAL and (iv) drug loading from 0.03 to 0.15% (w/w). Their in vitro photoactivity was investigated on the NuTu-19 ovarian cancer cell model derived from Fischer 344 rats and compared to free drug. Hy-loaded PLA NPs exhibited a higher photoactivity than free drug. Increasing light dose or incubation time with cells induced an enhanced activity of Hy-loaded PLA NPs. Increased NP drug loading had a negative effect on their photoactivity on NuTu-19 cells: at the same Hy concentration, the higher was the drug loading, the lower was the phototoxic effect. The influence of NP drug loading on the Hy release from NPs was also investigated.

Hypericin and Pulsed Laser Therapy of Squamous Cell Cancer in Vitro

OBJECTIVE

This in vitro study compares continuous wave and pulsed laser light at longer wavelengths for activation of the phototoxic drug hypericin in human cancer cells.

BACKGROUND DATA

Two-photon pulsed laser light now allows high-resolution fluorescent imaging of cancer cells and should provide deeper tissue penetration with near infrared light for improved detection as well as phototoxicity in human tumors.

METHODS

Cultured Seoul National University (SNU)-1 tumor cells from a squamous cell carcinoma (SCC) were incubated with hypericin before photoirradiation at four laser wavelengths. Phototoxicity of hypericin sensitized SCC cells was measured by dimethyl thiazoldiphenyl (MTT) tetrazolium bromide cell viability assays and by confocal fluorescence microscopy via 532-nm and infrared two-photon pulsed laser light.

RESULTS

Phototoxic response increased linearly with hypericin dose of 0.1-2 microM, light exposure time of 5-120 sec, and pulsed dye laser wavelengths of 514-593 nm. Light energy delivery for 50% cell phototoxicity (LD50) response was 9 joules at 514 nm, 3 joules at 550 nm, and less than 1 joule at the 593 nm hypericin light absorption maxima. Fluorescence confocal microscopy revealed membrane and perinuclear localization of hypericin in the SNU cells with membrane damage seen after excitation with visible 532 nm continuous wave light or two-photon 700-950 nm picosecond pulsed laser irradiation.

CONCLUSIONS

Hypericin may be a powerful tumor targetting drug when combined with pulsed laser light in patients with recurrent head and neck SCC.

Synthesis, in vitro cellular uptake and photo-induced antiproliferative effects of lipophilic hypericin acid derivatives

Hypericin, a naturally occurring hydroxylated phenanthroperylene dione, is used as a powerful photosensitizer for photodynamic therapy as well as a diagnostic tool for the fluorescence detection of flat neoplastic lesions in the bladder of patients. Both applications are based on the tumouritropic characteristics of the compound. To get more insight into some of the physicochemical properties of hypericin affecting its tumouritropic characteristics, we set out to synthesize a series of more lipophilic hypericins. For this purpose, a synthetic pathway to hypericin acid amides with hydrocarbon chains of different lengths stably attached by an amide bond at position C10 was explored. Hypericin acid proved inert in amide forming reactions, whereas the precursor protohypericin acid showed higher reactivity and resulted in the desired amide derivatives, which afterwards can be easily converted into their phenanthroperylene dione form. Hexyl-, octyl-, decyl- and dodecylamides of hypericin acid were successfully synthesized in this way. In vitro cellular uptake and photo-induced antiproliferative effects of the compounds were evaluated, using the human moderately differentiated non-invasive papillary transitional carcinoma RT-112 cell line. Whereas the more lipophilic amides were taken up limitedly, the hexylamide accumulated approx. as well as hypericin itself. From the antiproliferative data it can further be concluded that not only the cellular uptake, but also the light-induced activity, is affected by the introduced structural changes.

Uses of photodynamic therapy in premalignant and malignant lesions of the gastrointestinal tract beyond the esophagus

Much has recently been written regarding the use of photodynamic therapy for the treatment of esophageal carcinoma and dysplastic Barrett's esophagus. This review, however, describes the clinical experience using photodynamic therapy with various photosensitizer agents for the treatment of diseases in other areas of the gut, especially the pancreaticobiliary tract where European studies have established the role of porfimer sodium photodynamic therapy in the management of patients with cholangiocarcinoma.