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In this work, an upconversion luminescence (UCL) nanosensor for fast detection of ferric ion (Fe3+) and phosphate ion (Pi) is developed based on the inner-filter effect (IFE) between NaYF4:Yb/Er upconversion nanoparticles (UCNPs) and Fe3+-hypocrellin B (HB) complex. Fe3+-HB complex has strong absorption band (450–650 nm), which overlaps with the green emission peak of UCNPs at 545 nm. By adding Fe3+ and Pi, the UCNPs-HB system produces the red-shift change of absorption spectrum, which leads to the "on–off-on" process of IFE. So, with the specific recognition ability of HB for Fe3+ and the competitive complexation of Pi for Fe3+, the proposed nanosensor utilizes the UCL change to achieve the detection of the targets. For the detections of Fe3+, the linear range is 10–600 μM with a limit of detection (LOD) of 2.62 μM, and for Pi, the linear range is 5–100 μM with a LOD of 1.25 μM. The results for selectivity, precision, and recovery test are also satisfactory. Furthermore, the real sample detection shows that the proposed nanaosensor has a great potential in environmental and biological systems. An upconversion luminescence (UCL) nanosensor based on the inner-filter effect (IFE) between upconversion nanoparticles (UCNPs) and Fe3+-hypocrellin B (HB) complex for the detection of Fe3+ and phosphate ion has been proposed, which is promising to be a convenient and sensitive assay for monitoring Fe3+ and phosphate ion in different environments and biological systems. [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii is an opportunistic foodborne pathogen primarily found in powdered infant formula (PIF). To date, it remains challenging to control the growth of this ubiquitous bacterium. Herein, antimicrobial photodynamic inactivation (aPDI) was first employed to inactivate C. sakazakii. Through 460 nm light irradiation coupled with hypocrellin B, the survival rate of C. sakazakii was diminished by 3~4 log. The photokilling effect was mediated by the attenuated membrane integrity, as evidenced by PI staining. Besides, scanning electron microscopy showed the deformed and aggregated cell cluster, and intracellular ROS was augmented by 2~3 folds when light doses increase. In addition to planktonic cells, the biofilm formation of C. sakazakii was also affected, showing an OD590nm decline from 0.85 to 0.25. In terms of molecular aspects, a two-component system called CpxRA, along with their target genes, was deregulated during illumination. Using the knock-out strain of ΔCpxA, the bacterial viability was reduced by 2 log under aPDI, a wider gap than the wildtype strain. Based on the promoted expression of CpxR and OmpC, aPDI is likely to play its part through attenuating the function of CpxRA-OmpC pathway. Finally, the aPDI system was applied to PIF, and C. sakazakii was inactivated under various desiccated or heated storage conditions. Collectively, aPDI serves as an alternative approach to decontaminate C. sakazakii, providing a new strategy to reduce the health risks caused by this prevalent foodborne pathogen. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma (LUAD) is associated with poor prognosis. Identifying novel cancer targets and helpful therapeutic strategies remains a serious clinical challenge. This study detected differentially expressed genes in The Cancer Genome Atlas (TCGA) LUAD data collection. We also identified a predictive DNA biomarker, G protein-coupled receptor 37 (GPR37), which was verified as a prognostic biomarker with a critical role in tumor progression. In human LUAD specimens and microarray analyses, we determined that GPR37 was significantly upregulated and associated with a poor prognosis. GPR37 downregulation markedly inhibited the proliferation and migration of LUAD both in vitro and in vivo. Mechanistically, GPR37 could bind to CDK6, thereby facilitating tumor progression in LUAD by inducing cell cycle arrest at the G1 phase. GPR37 also facilitates tumorigenesis in xenograft tumors in vivo. High-throughput screening for GPR37-targeted drugs was performed using the Natural Products Library, which revealed the potential of Hypocrellin B to inhibit GPR37 and cell growth in LUAD. We demonstrated that Hypocrellin B suppressed LUAD cell proliferation and migration both in vitro and in vivo via GPR37 inhibition. Collectively, our findings reveal the role of GPR37 in LUAD progression and migration and the potential of GPR37 as a target for the treatment of LUAD. Thus, the specific inhibition of GPR37 by the natural product Hypocrellin B may possess the potential for the treatment of LUAD.

[Display omitted] • A glutathione responsive photosensitizer (HB−NBD) based on hypocrellin B (HB) was designed. • HB−NBD shows almost no fluorescence and 1O 2 generation due to PET process. • The HB can be released in the presence of GSH, resulting in high phototoxicity to cancer cells. As a typical natural photosensitizer, hypocrellin B (HB) offers the advantages of high molar extinction coefficient, high phototoxicity, low dark toxicity, and fast metabolism in vivo. However, the lack of tumor specificity hinders its clinical applications. Herein, we designed and synthesized a glutathione (GSH) responsive photosensitizer based on HB. The 7 − nitro − 2,1,3 − benzoxadiazole (NBD) covalently connected to HB not only served as a fluorescence quenching group but also as a GSH activating group. The photosensitizer HB−NBD showed almost no fluorescence and singlet oxygen generation as a result of the photoinduced electron transfer between HB and NBD. The designed photosensitizer HB−NBD can be activated by GSH in solutions and cancer cells, and then obtain recuperative fluorescence and photosensitive activity. [ABSTRACT FROM AUTHOR]

An antitumour chemo-photodynamic therapy nanoplatform was constructed based on phospholipid-coated NaYF 4 : Yb/Er upconversion nanoparticles (UCNPs). In this work, the amphiphilic block copolymer DSPE-PEG 2000 was combined with the surface ligand oleic acid of the UCNPs through hydrophobic interaction to form liposomes with a dense hydrophobic layer in which the photosensitizer hypocrellin B (HB) was assembled. The coated HB formed J-aggregates, which caused a large redshift in the absorption spectrum and improved the quantum efficiency of energy transfer. Furthermore, MnO 2 nanosheets grew in-situ on the liposomes through OMn coordination. Therefore, a multifunctional tumour microenvironment (TME)-responsive theranostic nanoplatform integrating photodynamic therapy (PDT) and chemodynamic therapy (CDT) was successfully developed. The results showed that this NIR-mediated chemo-photodynamic therapy nanoplatform was highly efficient for oncotherapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hepatocellular carcinoma (HCC) has been reported to be the third common malignant tumor because of the high rate of mortality. Photosensitizers (PSs) based on the natural products have been widely used in clinical antitumor research contributed to their excellent biological activity. To increase the PSs' safety and efficacy of HCC, the tumor cell membrane coating drug nanocrystals featured with homologous immune escape and targeting ability and low toxicity are in high demand. In this study, we reported a targeting drug delivery system based on a modified cell membrane coating technique and drug nanocrystals. HepG2 cell membrane was modified with targeting receptor through a biochemical reaction including Maleimide reaction. Modified with the HepG2-targeting protein transferrin, the resulting TF-CCCM-HB NPs exhibited long-term stability, excellent biocompatibility, high drug loading, and low toxicity. Compared with HB NPs, TF-CCCM-HB NPs showed both excellent targeting and therapeutic efficacy in BALB/c nude mouse bearing with HepG2 tumors. Therefore, TF-CCCM, a biomimetic drug delivery platform, can be readily generalized to the delivery of various drugs and provide a sound strategy for the treatment of other cancers via changes in the corresponding homotypic cancer cell membrane.

Peroxalate CL as an energy source to excite photosensitizers has attracted tremendous attention in photodynamic therapy (PDT). In this work, peroxyoxalate CPPO and hypocrellin B (HB)‐based nanoparticles (CBNPs) for ultrasound (US)‐enhanced self‐exciting PDT were designed and prepared. CBNPs showed an excellent therapeutic effect against cancer cells with the assistance of US. This US‐enhanced‐chemiluminescence system avoids the dependence on external light and provides an example for inspiring more effective and precise strategies for cancer treatment. [ABSTRACT FROM AUTHOR]

Background: The search for alternative therapeutics against antibiotic-resistant bacteria is highly desirable. A promising approach is photodynamic antimicrobial chemotherapy.///Objective: This work evaluated the photodynamic inactivation (PDI) efficacy of hypocrellin B (HB) on Gram-positive antibiotic-resistant bacteria.///Methods: PDI efficacy of HB on Gram-positive standard and antibiotic-resistant Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pneumonia and Gram-negative Escherichia coli and Klebsiella pneumoniae was assessed. HB photoactivity on biofilms formed by the Gram-positive bacteria and its cytotoxicity on mammalian CT26 cells were also investigated.///Results: HB showed no obvious dark toxicity, but provided concentration-dependent inactivation of bacteria and mammalian cells. After irradiation with 72 J/cm² light, 100 μM of HB achieved about 7 log10 reductions in bacterial survival of Gram-positive strains, but yielded only 2 log10 reductions in bacterial survival of Gram-negative strains. Gram-positive bacteria were as susceptible to PDI in biofilms as in planktonic suspensions, but the efficacy was attenuated.///Conclusions: The results suggested that HB could serve as a potential antibacterial photosensitizer against Gram-positive antibiotic-resistant bacteria. [ABSTRACT FROM AUTHOR]

• Hypocrellin B effectively inactivated C. albicans in the presence of light in vitro. • Azole-resistant isolate of C. albicans was sensitive to hypocrellin B-mediated photodynamic inactivation. • Hypocrellin B-mediated photodynamic inactivation induced damage to the cell wall, membrane, and cytoplasm. • The surface of C. albicans cells became twisted and ruptured after photodynamic inactivation treatment. The extensive use of antifungal drugs has led to resistance from Candida albicans. The search for alternative treatment against drug-resistant C. albicans is highly desirable. Antimicrobial photodynamic therapy (aPDT) is an emerging and promising approach for treating localized and superficial C. albicans infections. The aim of this study was to investigate the photodynamic inactivation (PDI) effects of hypocrellin B (HB) on azole-sensitive and resistant C. albicans in vitro. The PDI efficacies of HB on standard C. albicans strain (ATCC 10231), azole-sensitive clinical isolate of C. albicans , and azole-resistant clinical isolate of C. albicans were assessed. The uptake of HB in C. albicans cells was investigated by confocal laser scanning microscopy (CLSM). The PDI effects on cellular structure and surface characteristics were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). HB exhibited no significant dark toxicity, but inactivated the azole-sensitive and resistant C. albicans in a light-dose and PS concentration-dependent manner. CLSM images indicated that PDI treated C. albicans cells showed stronger fluorescence compared to untreated cells. TEM images suggested that significant damage to the cell wall, membrane, and cytoplasm were induced by HB-mediated PDI. SEM analysis revealed that the surface of C. albicans cells became twisted and ruptured after PDI treatment. Azole-sensitive and resistant C. albicans could be effectively inactivated by HB in the presence of light, and HB-mediated aPDT shows promise as an antifungal treatment for C. albicans. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to compare the different responses to hypocrellin B (HB)-mediated sonodynamic treatment between human gastric adenocarcinoma cell line SGC7901 and SGC7901/ADR.Methods: Tumor cells in culture dishes (35-mm diameter) were exposed to planar ultrasound at an intensity of 0.5 W/cm2 for 60 s combined with/without 2.5 μM HB. Cell viability was determined by MTT and Guava ViaCount assay. Production of reactive oxygen species (ROS) and destabilization of the mitochondrial membrane potential were assessed by flow cytometry. Apoptosis was analyzed using annexin-PE/7-amino-actinomycin D staining. The cell membrane integrity was estimated by isothiocyanate-dextran (FD500) uptake assay. Ultrastructural alterations on the membrane surface were observed by scanning electron microscopy. The membrane fluidity was also compared between the two cell lines using spectrophotometry.Results: Compared with SGC7901 cells, HB-mediated sonodynamic therapy (HB-SDT) showed higher cytotoxic in SGC7901/ADR cells at the same treatment doses. Abundant intracellular ROS, a decrease in the mitochondrial membrane potential, and an increased rate of apoptosis were detected in the SDT group of both cell lines, wherein SGC7901/ADR cells showed a much more higher rate. Cell membrane permeability was remarkably enhanced after HB-SDT application. In addition, relatively severe cell damage was observed under scanning electron microscopy after HB-SDT treatment in SGC7901/ADR cells compared with SGC7901 cells.Conclusions: These results suggest that HB-SDT could induce apoptosis in SGC7901 and SGC7901/ADR cells via production of ROS. SGC7901/ADR was found to be more sensitive to HB-SDT than SGC7901 cells under the same experimental condition. Meanwhile, a noteworthy difference in cell membrane injury between SGC7901 and SGC7901/ADR cells was detected. The decreased membrane fluidity in SGC7901/ADR cells may be one of the reasons for its increased membrane damage. [ABSTRACT FROM AUTHOR]

• Proapoptotic effect of hypocrellin B on A431 cells. • Treatment of photodynamic therapy using Red LED-light combined with hypocrellin B on cutaneous squamous cell carcinoma. • Application of hypocrellin B in skin squamous cell carcinoma. The incidence of cutaneous squamous cell carcinoma (cSCC) has been demonstrating yearly increases. cSCC is a malignant cancer and exerts a major impact on patients' health and quality of life. Thus, the development and use of novel therapies in the treatment of cSCC are needed. It has been reported that LED photodynamic therapy (LED PDT) mediated by Hypocrellin B and its derivatives, a second-generation photosensitizer, can induce apoptosis in a variety of tumor cells, However, its potential pro-apoptotic effects on cSCC have yet to be investigated. This study aims to investigate the pro-apoptotic effects and molecular mechanisms of HB-LED PDT in cutaneous squamous cell carcinoma A431 cells (Subsequent abbreviation A431 cells). Such information can provide an important theoretical foundation for the clinical translation of HB-LED PDT in the treatment of cSCC. 1. Effects of HB on A431 cells were determined using a Cell Counting Kit-8 assay, which method can indirectly reflect the number of living cells. In this way, this assay can then provide a means to identify the optimal concentrations of HB required for the induction of apoptosis in A431 cells. 2. The effects of HB-LED PDT on the morphology of A431 cells and changes in the nuclei after Hoechst33342 staining as determined using inverted fluorescent microscopy. 3. Use of the Annexin V-FITC test kit to detect levels of apoptosis in A431 cells in response to treatment with HB. Changes in reactive oxygen species and mitochondrial membrane potential following HB-LED PDT treatment in A431 cells were determined using fluorescence activated cell sorting (FACS). 4. Real-time quantitative PCR and Western Blot were applied to assess changes in several key factors involved in apoptosis including Bax, Bcl-2, and Caspase-3, at both transcription and translation levels. With these assays, it was possible to investigate the apoptotic signaling pathway in A431 cells in response to HB-LED PDT. HB-LED PDT inhibited proliferation activity and promoted nuclear fragmentation within these A431 cells. HB-LED PDT inhibited mitochondrial activity, increased reactive oxygen species production, and promoted apoptosis of A431 cells. In addition, several key factors in the apoptotic signaling pathway were increased at both the transcriptional and translational levels in A431 cells in response to the HB-LED PDT, indicating that the apoptotic signaling pathway was activated by HB-LED PDT. HB-LED PDT induces apoptosis in A431 cells through a mitochondria-mediated apoptotic pathway. Such findings serve as an important foundation for the development of new approaches in the treatment of cSCC. [ABSTRACT FROM AUTHOR]

In the present work, we have developed a photosensitizer hypocrellin B (HB) and nano silver loaded PLGA-TPGS nanoparticles with improved singlet oxygen production for enhanced photodynamic effect for the efficient treatment of age related macular degeneration. Random copolymer (PLGA-TPGS) synthesized by ring opening and bulk polymerization was characterized by IR, 1 H NMR and TGA analysis. HBS-CP-NPs prepared by nanoprecipitation techniques were spherical shaped 89.6–753.6 nm size particles with negative zeta potential. The average encapsulation efficiency was 84.06 ± 11.43% and HB release from the HBS-CP-NPs was found to be biphasic with a slow release of 1.41% in the first 8 h and 48.91% during 3 days as measured by RP-HPLC. DSC thermograms indicate that HB was dispersed as amorphous form in HBS-CP-NPs. The ROS generation level of HBS-CP-NPs was significantly higher than that of HB/HB-CP-NPs. The production of 1 O 2 of HBS-CP-NPs has been assessed using EPR spectrometer. The 1 O 2 generating efficiency follows the order of nano silver > HB-CP-NPs > HBS-CP-NPs > pure HB drug solution. The superior phototoxic effect of HBS-CP-NPs (85.5% at 50 μM) was attained at 2 h irradiation in A549 cells. Significant anti angiogenic effect of HBS-CP-NPs was observed in treated CAM embryos. Following intravenous injection of HBS-CP-NPs to rabbits, the maximum amount of HB was found in retina (3 h), iris (9 h), aqueous humour (9 h) and vitreous humour (9 h). [ABSTRACT FROM AUTHOR]

A nanoparticulate photodynamic approach was employed with an objective to achieve enhanced production of singlet oxygen ( 1 O 2 ), for the management of posterior segment eye diseases like age related macular degeneration. The hypocrellin B (HB) loaded poly lactide- co -glycolide nanoparticle formulations were incorporated with nano silver (HBS-NPs). The optimized HBS-NPs contained 2.60 ± 0.06 mg/mL of HB and showed (i) 135.6 to 828.2 nm size range, and (ii) negative zeta potential with a narrow polydispersity index. The DSC thermograms suggested the amorphous nature of HB inside the HBS-NPs. With the average encapsulation efficiency of 92.9 ± 1.79%, the drug release from the HBS-NPs followed a biphasic pattern with an initial burst of 3.50% during first 8 h followed by a sustained release of 47.82% within 3 days. The interaction between nano silver and HB as assessed by the increase in spectral intensity of Raman spectrum demonstrates that HB may be attached over the nano silver. Generation of reactive oxygen species (ROS) by HBS-NPs was significantly higher than that of HB/HB-NPs. The singlet oxygen generating efficiency assessed using EPR spectrometer follows the order of nano silver > HB-NPs > pure HB drug solution > HBS-NPs. The HBS-NPs had a concentration and time dependent phototoxicity on A549 (human adeno lung carcinoma) cells in the presence of light providing a superior phototoxic effect (82.2% at 50 μM) at 2 h irradiation. The CAM treated with HBS-NPs showed a significant anti-angiogenic effect compared to a blank formulation. In vivo biodistribution studies revealed that intravenous administration of HBS-NPs lead into significant exposure to the posterior segment of the eye. This proof of principle study demonstrates that HB based nanoparticles may be a valuable new tool for application in ocular photodynamic therapy for the treatment of AMD in future. [ABSTRACT FROM AUTHOR]

Objectives The aim of the present study is to investigate the effects of sonodynamic action of hypocrellin B on human breast cancer cells and further explore its underlying mechanisms. Methods The cell viability of breast cancer MDA-MB-231 cells was examined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Alterations on cell apoptosis, intracellular reactive oxygen species generation (ROS), mitochondrial membrane potential, and DNA fragmentation was analyzed by flow cytometer. The subcellular localization of hypocrellin B was assessed by a confocal laser scanning microscope. Mitochondria damage and nuclear morphological changes were observed under a fluorescence microscope. To further explore whether caspase pathway was involved in cell apoptotic induction of sonodynamic action of hypocrellin B, the pan-caspase inhibitor Z-Val-Ala-DL-Asp (ome)-Fluoromethylketone (z-VAD-fmk) was added to the cells one hour prior to loading the sonosensitizer, and then cell viability and apoptosis were analyzed after hypocrellin B treatment. Results Sonodynamic treatment of hypocrellin B HB significantly suppressed cell viability of MDA-MB-231 cells. Sonodynamic action of hypocrellin B caused excessive ROS accumulation, mitochondrial dysfunction, cell apoptosis, DNA fragmentation and nuclear morphological damage. Moreover, the cytotoxicity and cell apoptosis induced by sonodynamic action of hypocrellin B were remarkably rescued by the caspase spectrum inhibitor z-VAD-fmk. Conclusions These results demonstrated that hypocrellin B had significant sonodynamic killing and apoptotic induction effect on breast cancer cells. And cell apoptosis induced by sonodynamic action of hypocrellin B was partly dependent on caspase pathway. [ABSTRACT FROM AUTHOR]

Hypocrellin B (HB), a natural perylenequinone pigment, has been successfully employed in the photodynamic therapy (PDT) in a variety of human cancer cells due to its high singlet oxygen yield. To investigate the generation of nitric oxide (NO) and its role on cancer cell death induced by PDT, we used human hepatocellular carcinoma (HepG2) cells and HB as a photosensitizer. HB/light treatment decreased the growth of HepG2 cells in a dose-dependent manner with an IC 50 of 3.10 μM, activated caspase-3, -9 and induced apoptosis in HepG2 cells. It was found that exposure of the cells to HB/light resulted in inducible nitric oxide synthase (iNOS) activation and followed by significant increase in NO generation. Incubating cells with a NOS inhibitor N ω -monomethyl- l -arginine ( l -NMMA) and an NO scavenger 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) enhanced HB/light-induced caspase-3, -9 activation and apoptosis significantly while decreasing DAF fluorescence-assessed NO generation substantially. Cells could be rescued from HB/light-induced apoptosis by an exogenous NO donor, sodium nitroprusside (SNP). Our findings suggested that induced NO was acting cytoprotectively and PDT efficacy of HB could be improved by using pharmacological modulators of NO or NOS. [ABSTRACT FROM AUTHOR]

To increase the therapeutic efficacy of photodynamic therapy (PDT) in treating lung cancer, we developed both photosensitizer and anticancer drug encapsulated hyaluronic acid–ceramide nanoparticles. Based on our previous study, a co-delivery system of photosensitizers and anticancer agents greatly improves the therapeutic effect of PDT. Furthermore, hyaluronic acid–ceramide-based nanoparticles are ideal targeting carriers for lung cancer. In vitro phototoxicity in A549 (human lung adenocarcinoma) cells and in vivo antitumor efficacy in A549 tumor-bearing mice treated with hypocrellin B (HB)-loaded nanoparticles (HB-NPs) or hypocrellin B and paclitaxel loaded nanoparticles (HB–P-NPs) were evaluated. Cell viability assay, microscopic analysis and FACS analysis were performed for the in vitro studies and HB–P-NPs showed enhanced phototoxicity compared with HB-NPs. In the animal study, the tumor volume change and the histological analysis was studied and the anticancer efficacy improved in the order of free HB < HB-NPs < HB–P-NPs. In conclusion, the combination therapy of PDT and chemotherapy, and hyaluronic acid–ceramide nanoparticle-based targeted delivery improved the effects of PDT in lung cancer in mice. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes refractory infections and has recently become a serious public health concern. The present study was designed to investigate sonodynamic action of hypocrellin B on MRSA. A MRSA strain (ATCC BAA-43) was used in the present study. The dark toxicity of hypocrellin B on MRSA and its uptake in MRSA first were measured. And then bacteria were incubated with hypocrellin B and exposed to ultrasound. After sonodynamic treatment, colony forming unit assay and bacterial viability assay were conducted. Membrane permeability assay, DNA fragmentation assay, and DNA synthesis assay were also performed to examine the underlying mechanism. The results showed that hypocrellin B at concentrations of up to 500 μM had no toxicity to MRSA in the dark. After incubation for 50 min, hypocrellin B could be maximally absorbed by MRSA, and exhibited significant sonodynamic activity in a dose-dependent manner. The 5-log reduction in colony forming unit (CFU) was observed after hypocrellin B (40 μM) treatment at an intensity of 1.38 W/cm 2 ultrasound for 5 min. Compared to the control, hypocrellin B alone and ultrasound sonication alone group, more dead cells were found and bacterial membrane integrity was notably damaged after sonodynamic treatment of hypocrellin B. However, no remarkable DNA damage was found in MRSA after sonodynamic treatment of hypocrellin B. All the findings demonstrated that hypocrellin B could serve as a potential antibacterial sonosensitizer to significantly cause damage to the membrane integrity of MRSA and inhibit its growth under ultrasound sonication. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma (LUAD) is associated with poor prognosis. Identifying novel cancer targets and helpful therapeutic strategies remains a serious clinical challenge. This study detected differentially expressed genes in The Cancer Genome Atlas (TCGA) LUAD data collection. We also identified a predictive DNA biomarker, G protein-coupled receptor 37 (GPR37), which was verified as a prognostic biomarker with a critical role in tumor progression. In human LUAD specimens and microarray analyses, we determined that GPR37 was significantly upregulated and associated with a poor prognosis. GPR37 downregulation markedly inhibited the proliferation and migration of LUAD both in vitro and in vivo. Mechanistically, GPR37 could bind to CDK6, thereby facilitating tumor progression in LUAD by inducing cell cycle arrest at the G1 phase. GPR37 also facilitates tumorigenesis in xenograft tumors in vivo. High-throughput screening for GPR37-targeted drugs was performed using the Natural Products Library, which revealed the potential of Hypocrellin B to inhibit GPR37 and cell growth in LUAD. We demonstrated that Hypocrellin B suppressed LUAD cell proliferation and migration both in vitro and in vivo via GPR37 inhibition. Collectively, our findings reveal the role of GPR37 in LUAD progression and migration and the potential of GPR37 as a target for the treatment of LUAD. Thus, the specific inhibition of GPR37 by the natural product Hypocrellin B may possess the potential for the treatment of LUAD. [Display omitted] [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii is an opportunistic foodborne pathogen primarily found in powdered infant formula (PIF). To date, it remains challenging to control the growth of this ubiquitous bacterium. Herein, antimicrobial photodynamic inactivation (aPDI) was first employed to inactivate C. sakazakii . Through 460 nm light irradiation coupled with hypocrellin B, the survival rate of C. sakazakii was diminished by 3~4 log. The photokilling effect was mediated by the attenuated membrane integrity, as evidenced by PI staining. Besides, scanning electron microscopy showed the deformed and aggregated cell cluster, and intracellular ROS was augmented by 2~3 folds when light doses increase. In addition to planktonic cells, the biofilm formation of C. sakazakii was also affected, showing an OD 590nm decline from 0.85 to 0.25. In terms of molecular aspects, a two-component system called CpxRA, along with their target genes, was deregulated during illumination. Using the knock-out strain of ΔCpxA, the bacterial viability was reduced by 2 log under aPDI, a wider gap than the wildtype strain. Based on the promoted expression of CpxR and OmpC , aPDI is likely to play its part through attenuating the function of CpxRA-OmpC pathway. Finally, the aPDI system was applied to PIF, and C. sakazakii was inactivated under various desiccated or heated storage conditions. Collectively, aPDI serves as an alternative approach to decontaminate C. sakazakii , providing a new strategy to reduce the health risks caused by this prevalent foodborne pathogen., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Xu, Yao, Li, Liao, Wan, Liu, Ma, Tao, Wang and Xu.)

Purpose: To study subcellular localization of hypocrellin B in hepatocellular carcinoma cells, and hypocrellin B-mediated sonodynamic action-induced cell damage. Materials and methods: After incubation with 2.5 μM of hypocrellin B, human hepatocellular carcinoma HepG2 cells were exposed to ultrasound waves for 8 sec at an intensity of 0.46 W/cm2. Clonogenic survival of HepG2 cells was measured using a colony forming assay and light microscope. Ultrastructural morphology was observed using transmission electron microscope (TEM) and mitochondrial membrane potential (MMP) was assessed using confocal laser scanning microcope (CLSM) after rhodamine 123 staining. Additionally, subcellular localization of hypocrellin B in HepG2 cells with organelle probe staining was also observed using CLSM. Results: The colony forming units of HepG2 cells decreased substantially after sonodynamic treatment. The results of TEM showed microvilli disappearance, apoptotic body formation, swollen mitochondria with loss of cristae and mitochondrial myelin-like features (or membrane whorls). Collapse of MMP was found in the treated cells. Hypocrellin B was distributed in mitochondria and lysosomes as well as in endoplasmic reticulum and Golgi apparatus. Conclusions: The findings demonstrated that sonodynamic action of hypocrellin B induced mitochondrial damage, survival inhibition, and apoptosis of HepG2 cells. Additionally, other subcellular organelles such as endoplasmic reticulum, Golgi apparatus and lysosomes were also the targets of hypocrellin B-mediated sonodynamic action as well as mitochondria. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-photon system based on TiO 2 NP-HB was established and activated under visible light. • TiO 2 NP and HB showed synergy in photokilling S. aureus. • S. aureus elicited oxidative responsiveness by altering the status of the Cid/Lrg system. • Overexpression of LrgA in S. aureus strengthened the inactivation effect of TiO 2 NP-HB. • aPDI could be applied to apple decontamination while maintaining food quality. Staphylococcus aureus (S. aureus) is a foodborne pathogen that endangers human health worldwide. Antimicrobial photodynamic inactivation (aPDI), mediated by titanium dioxide nanoparticles (TiO 2 NP), was recently used to control the growth of S. aureus , however, UV illumination had to be offered to initiate the photodynamic reaction. To overcome this drawback, a dual-photon system was established here based on TiO 2 NP and hypocrellin B (HB), a natural pigment with photocatalyst activity. Irradiated at the visible light (9 J/cm2) at the wavelength of 460 nm, the joint use of both photosensitizers (PS) caused a substantial decline of staphylococcal survival, reaching a maximum decrease of 4 ∼ 5 logs. When 10 nM HB and 100 µM TiO 2 NP were applied, a synergistic photokilling effect was achieved, only in the mixed phase of anatase/rutile, Degussa P25. Regarding the antimicrobial mechanisms, it was found that the membrane integrity of S. aureus was heavily disrupted, surface morphology was altered, intracellular substances like potassium and DNA were leaked, and biofilm formation was significantly circumvented due to the excitation of sensitized PS. In terms of antioxidant responsiveness of S. aureus , qPCR results showed that a series of genes encoding the membrane-associated cell death effectors were deregulated. Among them, LrgA was recognized as a key responsive element, due that the mutant strain harboring a constitutively-expressed LrgA strengthened the bactericidal effect of aPDI. Finally, the dual-photon strategy lowered the microbial contamination in the tested apple with its quality maintained, under the condition of visible light. Taken together, a new dual-photon system based on TiO 2 NP and HB was constructed and validated in photokilling S. aureus , providing a well-adapted technique to maintain food safety. [ABSTRACT FROM AUTHOR]

Purpose: In the present study, we investigated effects of photodynamic therapy with hypocrellin B on apoptosis, adhesion, and migration of cancer cells in vitro. Materials and methods: Human ovarian cancer HO-8910 cell as a cancer model cell was incubated with hypocrellin B at a concentration of 2.5 μM for 5 h and irradiated by light from a light-emitting diodes (LED) source. Cell apoptosis was analyzed by flow cytometry with annexin V/propidium iodide (PI) staining and nuclear staining 6 h after hypocrellin B photoirradiation. Cell adhesion was assessed using the 3-(4, 5-dimthylthiazol-2-yl)-2, 5 diphenyl-tetrazolium bromide (MTT) assay 4 h after photodynamic treatment. Cell migration was measured 48 h after photodynamic treatment. Results: Flow cytometry with annexin V/PI staining showed that early apoptotic and late apoptotic (necrotic) rates following photodynamic therapy with hypocrellin B markedly increased to 16.40% and 24.67%, respectively. Nuclear staining found nuclear condensation and typical apoptotic body in the treated cells. The number of cell migration was significantly decreased to 183 ± 28 after photodynamic therapy with hypocrellin B ( p < 0.01). Light irradiation alone and hypocrellin B alone had no significant effect on cell migration. The cell adhesion inhibitory rate due to photodynamic action of hypocrellin B was 53.2 ± 1.8%, significantly higher than 2.7 ± 2.1% of light treatment alone and 1.0 ± 0.4% of hypocrellin B treatment alone ( p < 0.01). Conclusion: The findings demonstrated that photodynamic therapy with hypocrellin B remarkably induced apoptosis and inhibited adhesion and migration of cancer cells in vitro. [ABSTRACT FROM AUTHOR]

Abstract: The present work investigates the interaction of Hypocrellin B (HB) with AuTiO2 nanoparticles using absorption, cyclic voltammetry, fluorescence, time resolved and laser flash photolysis measurements. Broad absorption along with red-shift indicates the formation of charge-transfer complex between HB and AuTiO2 nanoparticles. The higher binding constant values obtained from absorption and fluorescence measurements envisage that the binding of HB with TiO2 was greatly enhanced by the surface modification with Au metal particles. The observed static type of fluorescence quenching was confirmed by life time measurements. Laser flash photolysis revealed that the electron transfer occurs from the excited HB to the conduction band of nanoparticles. [Copyright &y& Elsevier]

Summary: Objective: Staphylococcus aureus is a common opportunistic pathogen causing human infections. In the present study, we investigated photodynamic inactivation on S. aureus using hypocrellin B from a traditional Chinese herb. Materials and methods: After incubation of S. aureus cells with different concentrations of hypocrellin B for 60min, subsequent light irradiation from a novel LED light source with wavelength of 470nm was combined with the energy density of 0.3J/cm2. Phototoxicity of hypocrellin B on S. aureus was investigated by colony forming unit assay. Membrane permeability was measured using confocal laser scanning microscopy (CLSM) with propidium iodide (PI) staining. Intracellular reactive oxygen species (ROS) level was measured using flow cytometry (FCM) with DCFH-DA staining. Morphology and structure of treated and controlled bacteria were observed using transmission electron microscopy (TEM). Results: Activity of S. aureus was substantially inhibited by photodynamic action in hypocrellin B dose-dependent manner. Notable damage to S. aureus were found in TEM after photodynamic treatment of hypocellin B. Red fluorescence of PI dye was observed more frequently in bacterial cells treated by photodynamic action of hypocrellin B than those of bacterial cells treated by the controls including sham control, hypocrellin B treatment alone and light irradiation alone. Intracellular ROS increase was also found in S. aureus treated by photodynamic action of hypocrellin B. Conclusion: Photodynamic action of hypocrellin B markedly increased intracellular ROS level and caused damage to membrane permeability, resulting in cell death of S. aureus. [Copyright &y& Elsevier]

Highlights: [•] Hypocrellin B (Hyp B) quenches Mb fluorescence by forming two unique ground-state complexes on the surface of the enzyme. [•] Docking simulations reveal two binding sites for Hyp B: Tyr103 and Trp7, the former being more energetically accessible. [•] Upon Hyp B binding, the microenvironment of Trp becomes more hydrophilic while that of Tyr remains the same. [Copyright &y& Elsevier]

Summary: Objectives: Breast cancer is a common disease which threatens the life of women. To explore an alternative modality for combating breast cancer, a light-emitting diode (LED) that activates hypocrellin B was used in the present study to investigate apoptosis induction in breast cancer MDA-MB-231 cells. Materials and methods: Photocytotoxicity was investigated 24h after photodynamic treatment of hypocrellin B using MTT reduction assay and light microscopy. Apoptosis was observed 6h after photodynamic treatment using flow cytometry with Annexin V/PI staining as well as fluorescent microscopy with Hoechst33258 staining. The ultrastructure of the treated cells was observed using transmission electron microscopy (TEM). Results: Hypocrellin B-induced photocytotoxicity in MDA-MB-231 cells exhibited a dose-dependent manner. The amount of MDA-MB-231 cells attached to the bottom of well decreased significantly after photodynamic treatment of hypocrellin B. Flow cytometry showed that the early and late apoptotic rate of MDA-MB-231 cells increased remarkably up to 17.46% and 32.80%, respectively, after treatment of LED-activated hypocrellin B. In addition, nuclear condensation, fragmentation and chromatin margination, and topical apoptotic body in the treated cells were observed by nuclear staining and TEM. Conclusion: Photodynamic action of hypocrellin B irradiated by light-emitting diodes could significantly kill breast cancer cells and induce apoptotic cell death, which suggests LED-activated hypocrellin B is a promising strategy for combating breast cancer. [Copyright &y& Elsevier]

Abstract: Objective: The present study aims to investigate apoptosis of hepatocellular carcinoma cells induced by hypocrellin B-mediated sonodynamic action. Methods: The hypocrellin B concentration was kept constant at 2.5μM and cells from the hepatocellular carcinoma HepG2 cell line were exposed to ultrasound with an intensity of 0.46W/cm2 for 8s. Cell cytotoxicity was quantified using an MTT assay 24h after sonodynamic therapy (SDT) of hypocrellin B. Apoptosis was investigated using a flow cytometry with Annexin V-FITC and propidium iodine staining. Intracellular reactive oxygen species (ROS) levels were detected using a flow cytometry with 2,7-dichlorodihydrofluorecein diacetate (DCFH-DA) staining. Results: The cytotoxicity of hypocrellin B-mediated sonodynamic action on HepG2 cells was significantly higher than those of other treatments including ultrasound alone, hypocrellin B alone and sham treatment. Flow cytometry showed that hypocrellin B-induced sonodynamic action markedly enhanced the apoptotic rate of HepG2 cells. Increased ROS was observed in HepG2 cells after being treated with hypocrellin B-mediated sonodynamic action. Conclusions: Our data demonstrated that hypocrellin B-mediated sonodynamic action remarkably induced apoptosis of HepG2 cells, suggesting that apoptosis is an important mechanism of cell death induced by hypocrellin B-mediated SDT. [Copyright &y& Elsevier]

The binding of Hypocrellin B-TiO chelate with DNA has been studied by using absorption, steady state fluorescence, cyclic voltammetry, time resolved fluorescence and laser flash photolysis measurements. The experimental results show that the presence of TiO nanoparticles increases the binding of Hypocrellin B with DNA. The groove binding mode is confirmed by spectroscopic and docking studies. Laser flash photolysis studies confirm the presence of electrons in the conduction band of TiO which will produce active oxygen species and results in damage of DNA indicating the potential application of Hypocrellin B-TiO chelate in the field of photodynamic therapy (PDT). [ABSTRACT FROM AUTHOR]

Hypocrellin B (HB) was encapsulated into a phosphatidylcholine liposome. Encapsulation of HB into liposomes not only improved the delivery of this photosensitizer but also increased its photodynamic efficacy compared to free HB molecules. Liposomal HB showed a higher cellular uptake than free HB as measured by confocal microscopy and was internalized into cultured HeLa cells by caveolar endocytosis, which was lipid-raft-dependent. Cell viability measurements demonstrated that liposomal HB was more phototoxic to HeLa cells than free HB as a result of the higher concentration of intracellular HB delivered by the liposomal formulation. The encapsulation of HB influenced the cell death pathway by an increased rate of necrotic cells after irradiation versus free HB, and a Type II (singlet oxygen) mechanism was responsible for the photocytotoxicity. [ABSTRACT FROM PUBLISHER]

pH-responsive O photosensitizing systems may serve as selective photodynamic therapy (PDT) agents by targeting the acidic interstitial fluid of many kinds of tumors. In this work, a natural and clinically used photosensitizer (Hypocrellin B, HB) and a pH indicator (Bromocresol Purple, BCP) were co-encapsulated in organically modified silica nanoparticles. BCP successfully regulated the O generation efficiency of HB through the 'inner filter' effect, which shows much stronger O generation ability in an acidic than in a basic environment. In vitro experiments also demonstrated that HB-doped nanoparticles are effective in killing tumor cells by PDT. [ABSTRACT FROM AUTHOR]

Fibrotic processes in tissues are characterised by an excessive accumulation of collagen containing increased levels of pyridinoline cross-links, which has been taken as an important criterion to diagnose the fibrosis. Hypocrellin B (HB) is a natural photosensitizer with excellent photodynamic activity but very low dark-toxicity. In the current work, main purpose was to clarify if photodynamic action of HB could be applied to regulating the level of pyridinoline cross-link in collagen. To use gelatin as a model collagen, it was observed that the pyridinoline crass-link formation was effectively degraded by HB photodynamic action in the gelatin, suggesting the level of pyridinoline cross-link formation in collagen may be photodynamically regulated to a normal level. Furthermore, mechanism of the photodynamic action of HB was studied. [ABSTRACT FROM AUTHOR]

The interaction of anticancer drug hypocrellin B (HB) and mono-cysteine substituted hypocrellin B (MCHB) with calf thymus deoxyribonucleic acid (CT-DNA) has been investigated using spectral methods. The results of UV–visible spectra showed that the HB and MCHB can intercalate into the base-stacking domain of the CT-DNA double helix. Further studies based on fluorescence spectroscopy and circular dichroism (CD) spectroscopy also supported the intercalation mechanism. [ABSTRACT FROM AUTHOR]

Abstract: We first synthesized and characterized a monomer ruthenium complex of hypocrellin B (HB) by chelation with Ru(bpy)2Cl2 (in which bpy=2,2′-bipyridine). It possesses the photosensitizing properties and can be applied in photodynamic therapy (PDT). The chemiluminescence assays indicated that the photodamage ability of the complex is stronger than that of HB. [Copyright &y& Elsevier]

Liposome is well known as not only a drug-delivery system but also a simple model for biological membranes. It was reported that fluorescence properties of hypocrellins were changeable over some extreme pH values. In the current work, the effects of the microenvironments on the fluorescence properties of HB in liposome, including approximately physiological range of pH values pH = 6.0-8.0, concentration of cholesterols and ionic strength of the solution, were studied. It was found that the fluorescence intensity of HB was sensitive to and also regulated by the microenvironments. When concentration of cholesterols and ionic strength keep invariable in PBS solution, there exists the maximum for the fluorescence of HB-liposome at pH 7.4 while the minimum for that of HB at pH 7.0. In addition, when pH value keeps constant (7.2), there exists the maximum at the ionic strength of 0.12 mol/kg while that at the concentration of 6×10−4 mol/L for cholesterols. On the other hand, in PBS solution, the lower the ionic strength is, the higher the fluorescence intensity is. The environment-sensitive fluorescence may be potentially applicable to probe some specific environmental features in cells or tissues. [ABSTRACT FROM AUTHOR]

The behavior of the semiquinone anion radical of hypocrellin B (HB), produced by electrolysis, has been studied by cyclic voltammetry, steady-state electron spin resonance, timeresolved electron spin resonance and in situ UV-Vis spectra. The results showed that the formation mechanisms of HB—· were different between electrolysis and photolysis, and the disproportionation of semiquinone anion radical of HB (HB—·) could not occur in dimethylsulfoxide; on the contrary, a syn-proportionation reaction in which HB2— reacts with HB to form HB—· was observed experimentally. At the same time, the kinetic parameters of HB—· were obtained from the time-decay experiments of HB—·. [ABSTRACT FROM AUTHOR]

TiO2 semiconductor colloids have been successfully employed in environmental clean-up, antibacterial and bactericidal action under ultraviolet light due to its strong redox ability and high yield of active oxygen species (1O2, O2·−, ·OOH) generation. Hypocrellin B, isolated from Hypocrella bambusae (B.et.Br) Sacc, a natural pigment with strong and broad absorption over the visible light region, was used in our work in an attempt to extend the photoresponse of TiO2 to visible light and maintain the high generation of active oxygen under visible light illumination. The formation of the HB–TiO2 chelate was characterized by UV–Vis and surface enhanced raman spectroscopy (SERS) and it was found that the chelate still had high efficiency of active oxygen generation. The possible generation mechanism was explored by Electron Paramagnetic Resonance (EPR) and time-resolved transient spectra techniques, showing that singlet oxygen (1O2) and superoxide radical anion (O2·−) were produced via energy transfer and electron transfer, respectively. The application of HB–TiO2 chelate in environment protection and bacteria sterilization was implied. [Copyright &y& Elsevier]

Laser Raman spectroscopy was used to investigate the photodamage characteristics of human erythrocyte membranes sensitized by hypocrellin B (HB) at the molecular level. It brought to light that the essence of the changes of erythrocyte membranes’ functions caused by membrane protein cross-linking and membrane lipid peroxidation, including increase of fluidity and ion permeability of membranes, etc., was that the orderly structure of erythrocyte membranes had been damaged by the active oxygen (1O2, O2 and, OH) generated by HB, including the decrease of α-helix, β-sheet and the increase of random coil in the main-chain of membrane proteins, the decrease of mercapto groups, indole rings, p-hydroxy phenyl rings, monosubstituted phenyl rings, etc. in the side-chain, and the changes of the conformations of membrane lipids as well. With the increase of the irradiation time, the trans conformation of membrane lipids increased first, then decreased. On the contrary, the gauche conformation decreased first, then increased. In addition, the decrease of the intensities of the lines assigned to bending vibration of the conformation-insensitive CH2 and CH3 of membrane proteins and lipids suggested that break of their chains had occurred. [ABSTRACT FROM AUTHOR]

Laser Raman spectroscopy provided the direct evidence for microcosmic photodamage in space structure of DNA molecule. When photosensitive damage was made to space structure of calf thymus DNA by hypocrellins A and B. the Raman characteristic frequencies and the intensities of the bands assigned to various groups of the components of DNA (phosphate backbone dsoxyribose and four bases) changed at various degrees. There were not only the strsnd breakage, but also the breakage of some H-bonds and disruption of vertical base-base stacking interactions. The photosensitive damage of hypocrellin B on DNA was stronger than that of hypocrellin A on DNA. [ABSTRACT FROM AUTHOR]