Comparison of intestinal toxicity in enhancing intestinal permeability and in causing ROS production of six PPD quinones in Caenorhabditis elegans.

As the derivatives of p-phenylenediamines (PPDs), PPD quinones (PPDQs) have received increasing attention due to their possible exposure risk. We compared the intestinal toxicity of six PPDQs (6-PPDQ, 77PDQ, CPPDQ, DPPDQ, DTPDQ and IPPDQ) in Caenorhabditis elegans. In the range of 0.01-10 µg/L, only 77PDQ (10 µg/L) moderately induced the lethality. All the examined PPDQs at 0.01-10 µg/L did not affect intestinal morphology. Different from this, exposure to 6-PPDQ (1-10 µg/L), 77PDQ (0.1-10 µg/L), CPPDQ (1-10 µg/L), DPPDQ (1-10 µg/L), DTPDQ (1-10 µg/L), and IPPDQ (10 µg/L) enhanced intestinal permeability to different degrees. Meanwhile, exposure to 6-PPDQ (0.1-10 µg/L), 77PDQ (0.01-10 µg/L), CPPDQ (0.1-10 µg/L), DPPDQ (0.1-10 µg/L), DTPDQ (1-10 µg/L), and IPPDQ (1-10 µg/L) resulted in intestinal reactive oxygen species (ROS) production and activation of both SOD-3::GFP and GST-4::GFP. In 6-PPDQ, 77PDQ, CPPDQ, DPPDQ, DTPDQ, and/or IPPDQ exposed nematodes, the ROS production was strengthened by RNAi of genes (acs-22, erm-1, hmp-2, and pkc-3) governing functional state of intestinal barrier. Additionally, expressions of acs-22, erm-1, hmp-2, and pkc-3 were negatively correlated with intestinal ROS production in nematodes exposed to 6-PPDQ, 77PDQ, CPPDQ, DPPDQ, DTPDQ, and/or IPPDQ. Therefore, exposure to different PPDQs differentially induced the intestinal toxicity on nematodes. Our data highlighted potential exposure risk of PPDQs at low concentrations to organisms by inducing intestinal toxicity.

Toxicity of substituted p-phenylenediamine antioxidants and their derived novel quinones on aquatic bacterium: Acute effects and mechanistic insights.

Substituted para-phenylenediamines (PPDs) are synthetic chemicals used globally for rubber antioxidation, with their quinone derivatives (PPD-Qs) raising particular environmental concerns due to their severe toxicity to aquatic organisms. Emerging research has identified a variety of novel PPD-Qs ubiquitously detected in the environment, yet experimental proof for the toxicity of PPD-Qs has not been forthcoming due to the unavailability of bulk standards, leaving substantial gaps in the prioritization and mechanistic investigation of such novel pollutants. Here, we use synthesized chemical standards to study the acute toxicity and underlying mechanism of 18 PPD-Qs and PPDs to the aquatic bacterium V. fischeri. Bioluminescence inhibition EC50 of PPD-Qs ranged from 1.76-15.6 mg/L, with several emerging PPD-Qs demonstrating significantly higher toxicity than the well-studied 6PPD-Q. This finding suggests a broad toxicological threat PPD-Qs pose to the aquatic bacterium, other than 6PPD-Q. Biological response assays revealed that PPD-Qs can reduce the esterase activity, cause cell membrane damage and intracellular oxidative stress. Molecular docking unveiled multiple interactions of PPD-Qs with the luciferase in V. fischeri, suggesting their potential functional impacts on proteins through competitive binding. Our results provided crucial toxicity benchmarks for PPD-Qs, prioritized these novel pollutants and shed light on the potential toxicological mechanisms.

Widespread occurrence of two typical N, N'-substituted p-phenylenediamines and their quinones in humans: Association with oxidative stress and liver damage.

While N, N'-substituted p-phenylenediamines (PPDs) and their quinone derivatives (PPDQs) have been widely detected in the environment, there is currently limited data on their occurrence in humans. In this study, we conducted the first serum analysis of two PPDs and PPDQs in the healthy and secondary nonalcoholic fatty liver disease (S-NAFLD) cohorts in South China. The concentrations of four oxidative stress biomarkers (OSBs), namely, 8-iso-prostaglandin F2α (8-PGF2α), 11ß-prostaglandin F2α (11-PGF2α), 15(R)-prostaglandin F2α (15-PGF2α), and 8-hydroxy-2'-deoxyguanosine in serum samples were also measured. Results showed that N-(1,3-dimethybutyl)-N'-phenyl-p-phenylenediamine (6PPD) quinone was the predominant target analytes both in the healthy and S-NAFLD cohorts, with the median concentrations of 0.13 and 0.20 ng/mL, respectively. Significant (p < 0.05) and positive correlations were found between 6PPD concentration and 8-PGF2α, 11-PGF2α, and 15-PGF2α in both the healthy and S-NAFLD cohorts, indicating that 6PPD may be associated with lipid oxidative damage. In addition, concentrations of 6PPD in serum were associated significantly linked with total bilirubin (ß = 0.180 µmol/L, 95%CI: 0.036-0.396) and direct bilirubin (DBIL, ß = 0.321 µmol/L, 95%CI: 0.035-0.677) related to hepatotoxicity. Furthermore, 8-PGF2α, 11-PGF2α, and 15-PGF2α mediated 17.1%, 24.5%, and 16.6% of 6PPD-associated DBIL elevations, respectively. Conclusively, this study provides novel insights into human exposure to and hepatotoxicity assessment of PPDs and PPDQs.

Occurrence and Fate of Substituted p-Phenylenediamine-Derived Quinones in Hong Kong Wastewater Treatment Plants.

para-Phenylenediamine quinones (PPD-Qs) are a newly discovered class of transformation products derived from para-phenylenediamine (PPD) antioxidants. These compounds are prevalent in runoff, roadside soil, and particulate matter. One compound among these, N-1,3-dimethylbutyl-n'-phenyl-p-phenylenediamine quinone (6PPD-Q), was found to induce acute mortality of coho salmon, rainbow trout, and brook trout, with the median lethal concentrations even lower than its appearance in the surface and receiving water system. However, there was limited knowledge about the occurrence and fate of these emerging environmental contaminants in wastewater treatment plants (WWTPs), which is crucial for effective pollutant removal via municipal wastewater networks. In the current study, we performed a comprehensive investigation of a suite of PPD-Qs along with their parent compounds across the influent, effluent, and biosolids during each processing unit in four typical WWTPs in Hong Kong. The total concentrations of PPDs and PPD-Qs in the influent were determined to be 2.7-90 and 14-830 ng/L. In the effluent, their concentrations decreased to 0.59-40 and 2.8-140 ng/L, respectively. The median removal efficiency for PPD-Qs varied between 53.0 and 91.0% across the WWTPs, indicating that a considerable proportion of these contaminants may not be fully eliminated through the current processing technology. Mass flow analyses revealed that relatively higher levels of PPD-Qs were retained in the sewage sludge (20.0%) rather than in the wastewater (16.9%). In comparison to PPDs, PPD-Qs with higher half-lives exhibited higher release levels via effluent wastewater, which raises particular concerns about their environmental consequences to aquatic ecosystems.

Polybrominated diphenyl ether quinone exposure leads to ROS-driven lysosomal damage, mitochondrial dysfunction and NLRP3 inflammasome activation.

Polybrominated diphenyl ethers (PBDEs) are aromatic compounds that containing bromine atoms, which possess high efficiency, good thermal stability. However, PBDEs had various known toxic effects and were characterized as persistent environmental pollutants. Exposure to a quinone-type metabolite of PBDEs (PBDEQ) is linked with excess production of intracellular reactive oxygen species (ROS) in our previous studies. Here, we observed that PBDEQ exposure led to ROS and mitochondrial dysfunction, which promoted canonical and non-canonical Nod-like receptor protein 3 (NLRP3) inflammasome activation. Further experiments demonstrated that PBDEQ exposure activated Toll-like receptors (TLRs), subsequently regulating nuclear factor kappa B (NF-κB) signaling. Moreover, lysosomal damage and K+ efflux were involved in PBDEQ-driven NLRP3 inflammasome activation. Our in vivo study also illustrated that PBDEQ administration induced liver inflammation in male C57BL/6J mice. Cumulatively, our current finding provided novel insights into PBDEQ-induced pro-inflammatory responses.

New quinones, a sesquiterpene and phenol compounds with cytotoxic activity from the aerial parts of Morinda umbellata L.

Eight previously undescribed compounds, two quinones (1-2), one sesquiterpene (3), and five phenol compounds (4-8), including three enantiomers (6a, 7a, and 8a), along with three corresponding known enantiomers (6b-8b) were isolated from the aerial parts of Morinda umbellata L. Their structures were elucidated by 1D and 2D NMR spectroscopy, X-ray diffraction, and experimental and calculated ECD spectra, respectively. Compound 5 was found to have weak cytotoxity, which inhibited the growth of seven human cancer cell lines (A2780, HeLa, MCF-7, BGC-823, H7420, Ketr3 and SW 1990) with IC50 values from 13.3 to 15.1 µM.

The Oxidation of Equol by Tyrosinase Produces a Unique Di-ortho-Quinone: Possible Implications for Melanocyte Toxicity.

Equol (7-hydroxy-3-(4'-hydroxyphenyl)-chroman, EQ), one of the major intestinally derived metabolites of daidzein, the principal isoflavane found in soybeans and most soy foods, has recently attracted increased interest as a health-beneficial compound for estrogen-dependent diseases. However, based on its structure with two p-substituted phenols, this study aimed to examine whether EQ is a substrate for tyrosinase and whether it produces o-quinone metabolites that are highly cytotoxic to melanocyte. First, the tyrosinase-catalyzed oxidation of EQ was performed, which yielded three EQ-quinones. They were identified after being reduced to their corresponding catechols with NaBH4 or L-ascorbic acid. The binding of the EQ-quinones to N-acetyl-L-cysteine (NAC), glutathione (GSH), and bovine serum albumin via their cysteine residues was then examined. NAC and GSH afforded two mono-adducts and one di-adduct, which were identified by NMR and MS analysis. It was also found that EQ was oxidized to EQ-di-quinone in cells expressing human tyrosinase. Finally, it was confirmed that the EQ-oligomer, the EQ oxidation product, exerted potent pro-oxidant activity by oxidizing GSH to the oxidized GSSG and concomitantly producing H2O2. These results suggest that EQ-quinones could be cytotoxic to melanocytes due to their binding to cellular proteins.

The 3,4-Quinones of Estrone and Estradiol Are the Initiators of Cancer whereas Resveratrol and N-acetylcysteine Are the Preventers.

This article reviews evidence suggesting that a common mechanism of initiation leads to the development of many prevalent types of cancer. Endogenous estrogens, in the form of catechol estrogen-3,4-quinones, play a central role in this pathway of cancer initiation. The catechol estrogen-3,4-quinones react with specific purine bases in DNA to form depurinating estrogen-DNA adducts that generate apurinic sites. The apurinic sites can then lead to cancer-causing mutations. The process of cancer initiation has been demonstrated using results from test tube reactions, cultured mammalian cells, and human subjects. Increased amounts of estrogen-DNA adducts are found not only in people with several different types of cancer but also in women at high risk for breast cancer, indicating that the formation of adducts is on the pathway to cancer initiation. Two compounds, resveratrol, and N-acetylcysteine, are particularly good at preventing the formation of estrogen-DNA adducts in humans and are, thus, potential cancer-prevention compounds.

Nucleophilic and redox properties of polybrominated diphenyl ether derived-quinone/hydroquinone metabolites are responsible for their neurotoxicity.

Polybrominated diphenyl ethers (PBDEs) are a category of brominated flame retardants, which were widely used in industrial products since the 1970 s. Our previous studies indicated quinone-type metabolites of PBDEs (PBDE-Qs) cause neurotoxicity, however, their inherent toxicological mechanism remains unclear. Here, we first synthesized PBDE-Qs and corresponding reduced hydroquinone homologous (PBDE-HQs) with different pattern of bromine substitution. Their nucleophilic and redox properties were investigated. PBDE-Qs react with reduced glutathione (GSH) via Michael addition and bromine displacement reaction, whilst PBDE-HQs lack the ability of reacting with GSH. Of note, the displacement reaction only occurs with bromine on the quinone ring of PBDE-Qs but not phenyl ring. Next, electron paramagnetic resonance (EPR) analysis revealed the generation of SQ•-, along with their downstream hydroxyl radical (HO•) and methyl radical (•CH3) through a PBDE quinone/semiquinone/hydroquinone (Q/SQ•-/HQ) futile cycle. In addition, a structure-dependent cytotoxicity pattern was found, the exposure of PBDE-Q/HQ with bromine substitution on the quinone ring resulted in higher level of apoptosis and autophagy in BV2 cells. In conclusion, this work clearly demonstrated that the nucleophilic and redox properties of PBDE-Qs/HQs are responsible for their neurotoxicity, and this finding provide better understanding of neurotoxicity of PBDEs.

Polybrominated Diphenyl Ethers Quinone Induces NCOA4-Mediated Ferritinophagy through Selectively Autophagic Degradation of Ferritin.

Polybrominated diphenyl ethers (PBDEs) have been detected ubiquitously in biological and environmental samples. Growing epidemiological data suggested the obvious correlation of PBDEs exposure with adverse health outcomes toward human beings, but exact molecular mechanism(s) are limited. Especially, the toxicological information regarding PBDEs metabolites is missing. Thereafter, this study intends to explore unidentified cell death modalities caused by PBDEs reactive quinone-type metabolite, PBDEQ. We found that PBDEQ induces autophagy in an ROS-dependent manner. Interestingly, the results indicated that PBDEQ degraded ferritin and activated a selective autophagy (termed as ferritinophagy) by using NCOA4 as its cargo receptor. These processes may further promote the release of iron and ROS. These results suggested the incidence of ferritinophagy induced by PBDEQ, which may contribute to PBDE exposure-caused diseases and dysfunctions.

Reaction of quinones with proteins: Kinetics of adduct formation, effects on enzymatic activity and protein structure, and potential reversibility of modifications.

Quinones are a common motif in many biological compounds, and have been linked to tissue damage as they can undergo redox cycling to generate radicals, and/or act as Michael acceptors with nucleophiles, such as protein Cys residues, with consequent adduct formation. The kinetics and consequences of these Michael reactions are poorly characterized. In this study we hypothesized that adduction of protein Cys residues with quinones would be rapid, structure-dependent, quantitatively-significant, and result in altered protein structure and function. Multiple quinones were incubated with glyceraldehyde-3-phosphate dehydrogenase (GAPDH), creatine kinase (CK), papain, bovine (BSA) and human (HSA) serum albumins, with the kinetics of adduction and effects on protein structure and activity determined. Adduction rate constants at Cys residues, which were dependent on the quinone and protein structure, and thiol pKa, are in the range 102-105 M-1 s-1. p-Benzoquinone (BQ) induced dimerization of GAPDH and CK (but not BSA, HSA, or papain) in a dose- and time-dependent manner. Incubation of purified proteins, or cell lysates, with quinones resulted in a rapid loss of GAPDH and CK activity; this loss correlated well with the rate constant for Cys adduction. Glutathione (GSH) reacts competitively with quinones, and could reverse the loss of activity and dimerization of GAPDH and CK. Mass spectrometry peptide mass mapping provided evidence for BQ adduction to GAPDH to specific Cys residues (Cys149, Cys244), whereas all Cys residues in CK were modified. These data suggested that quinones can induce biological effects by rapid and selective formation of adducts with Cys residues in proteins.

Attributes of Polygonum multiflorum to transfigure red biotechnology.

A vast array of plant-based compounds has enriched red biotechnology to serve the human health and food. A peculiar medicinal plant which was an element of traditional Chinese medicine for centuries as a liver and kidney tonic, for life longevity and hair blackening, is Polygonum multiflorum Thunb. (PM) which is popularly known as "He shou wu" or "Fo-ti" and is rich in chemical components like stilbenes, quinones, and flavonoids which have been used as anti-aging, anti-alopecia, anti-cancer, anti-oxidative, anti-bacterial, anti-hyperlipidemia, anti-atherosclerosis, and immunomodulating and hepatoprotective agents in the modern medicine. The health benefits from PM are attained since long through commercial products such as PM root powder, extract, capsules, tincture, shampoo, and body sprays in the market. Currently, the production of these pharmaceuticals and functional foods possessing stilbenes, quinones, and flavonoids is through cell and organ cultures to meet the commercial demand. However, hepatotoxic effects of PM-based products are the stumbling blocks for its long-term usage. The current review encompasses a comprehensive account of bioactive compounds of PM roots, their biological activities as well as efficacy and toxicity issues of PM ingredients and future perspectives.

Polychlorinated biphenyl quinone-induced signaling transition from autophagy to apoptosis is regulated by HMGB1 and p53 in human hepatoma HepG2 cells.

Autophagy, which works to remove stress and maintain cellular homeostasis, is usually considered a "pro-survival" signal. Contrarily, apoptosis is programmed "pro-death" machinery. Polychlorinated biphenyls (PCBs) are a group of ubiquitous industrial pollutants. Our previous studies illustrated that a PCB quinone metabolite, PCB29-pQ, elicited both autophagy and apoptosis. However, the signaling underlying the autophagy and apoptosis cross-talk has not been characterized. Here, we found that PCB29-pQ-induced autophagy mainly occurred at a lower concentration (5 µM), while apoptosis mostly arose at a higher concentration (15 µM) in HepG2 cells. Next, we demonstrated the elevation of intracellular calcium levels and calpain activity with PCB29-pQ treatment; however, the unaffected subcellular location of truncated ATG5 and Beclin1 suggested the irrelevance of calpain towards the autophagy-to-apoptosis signaling shift. HMGB1 and p53 both serve as transcription factors that play crucial roles in the regulation of PCB29-pQ-induced autophagy and apoptosis. PCB29-pQ not only enhanced the expression of HMGB1 and p53 but also promoted their binding and cytosolic translocation. Interestingly, HMGB1 rather than p53 plays a primary role in 5 µM of PCB29-pQ-induced autophagy in the nucleus; however, p53 promoted apoptosis to a great extent in the cytosol at the dose of 15 µM PCB29-pQ. Together, HMGB1 and p53 provided a subtle balance between autophagy and apoptosis, thus determining the fate of PCB29-pQ-treated cells.

Exploring the antimalarial potential of the methoxy-thiazinoquinone scaffold: Identification of a new lead candidate.

A small library of antiplasmodial methoxy-thiazinoquinones, rationally designed on the model of the previously identified hit 1, has been prepared by a simple and inexpensive procedure. The synthetic derivatives have been subjected to in vitro pharmacological screening, including antiplasmodial and toxicity assays. These studies afforded a new lead candidate, compound 9, endowed with higher antiplasmodial potency compared to 1, a good selectivity index when tested against a panel of mammalian cells, no toxicity against RBCs, a synergistic antiplasmodial action in combination with dihydroartemisinin, and a promising inhibitory activity on stage V gametocyte growth. Computational studies provided useful insights into the structural requirements needed for the antiplasmodial activity of thiazinoquinone compounds and on their putative mechanism of action.

Development of copolymeric nanoparticles of hypocrellin B: Enhanced phototoxic effect and ocular distribution.

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, 1H NMR and TGA analysis. HBS-CP-NPs prepared by nanoprecipitation techniques were spherical shaped 89.6-753.6nm 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 8h and 48.91% during 3days 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 1O2 of HBS-CP-NPs has been assessed using EPR spectrometer. The 1O2 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 50µM) was attained at 2h 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 (3h), iris (9h), aqueous humour (9h) and vitreous humour (9h).

Therapeutic Application of Natural Medicine Monomers in Cancer Treatment.

BACKGROUND: Natural medicine monomers (NMMs) isolated from plants have been recognized for their roles in treating different human diseases including cancers. Many NMMs exhibit effective anti-cancer activities and can be used as drugs or adjuvant agents to enhance the efficacy of chemotherapy and radiotherapy. Some NMMs, such as paclitaxel and camptothecin, have been extensively studied for decades and are now used as anti-cancer medicines due to their remarkable curative effects, such as inhibiting cancer cell proliferation and metastasis, and inducing cell death and differentiation. METHODS: After extensively reviewing papers related to NMM studies in cancers, we grouped NMMs into six categories based on their chemical structures. We summarized the anti-cancer activities of these NMMs and current knowledge of molecular mechanisms for them to exert their functions. RESULTS AND CONCLUSION: Many NMMs from plants can effectively inhibit cancer cells with low or tolerable toxicity to patients. Some NMMs have been well-characterized for their anti-cancer activities and have already been used as clinical drugs or adjuvant agents; however, the mechanisms underlying the cancer suppressive activities of most NMMs remain poorly understood. Many NMMs can be used as initial structural scaffolds to design and develop novel therapeutics against cancers. This review summarizes reports related to signaling pathways mediated by different NMMs and can provide a theoretical basis for clinical application and new drug development of NMMs.

The electrophilic character of quinones is essential for the suppression of Bach1.

The activation of nuclear factor erythroid 2-related factor 2 (Nrf2) is the most important cellular defense mechanisms against oxidative attack. BTB and CNC homology-1 (Bach1), like Kelch-like ECH-associated protein 1 (Keap1), is one of a negative regulator of Nrf2 that control antioxidant response elements (ARE)-dependent gene expressions. In the current study, we found that quinones show greater capacity than hydroquinones in nuclear Bach1 export, as well as ubiquitin-dependent Bach1 degradation in our experimental time frame. Consistently, quinones are easier than hydroquinones in Nrf2 activation and ARE-driven antioxidant protein expressions. Considering the redox cycling potential of quinone-hydroquinone couple, we investigated the effect of transit metal oxidation on the regulation of Nrf2 activity. As shown, Fe3+ enhanced hydroquinone-induced Nrf2 activation and ARE-driven gene expressions, suggesting quinones rather than hydroquinone activate Nrf2 through Bach1 arylation. Taking together, our investigation illustrated that the electrophilic character of quinones ensure their conjugation with Bach1, which is important for the downregulation of Bach1 and the upregulation of Nrf2 signaling.

An ortho-Iminoquinone Compound Reacts with Lysine Inhibiting Aggregation while Remodeling Mature Amyloid Fibrils.

Protein aggregation is a hallmark of several neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. It has been shown that lysine residues play a key role in the formation of these aggregates. Thus, the ability to disrupt aggregate formation by covalently modifying lysine residues could lead to the discovery of therapeutically relevant antiamyloidogenesis compounds. Herein, we demonstrate that an ortho-iminoquinone (IQ) can be utilized to inhibit amyloid aggregation. Using alpha-synuclein and Aß1-40 as model amyloidogenic proteins, we observed that IQ was able to react with lysine residues and reduce amyloid aggregation. We also observed that IQ reacted with free amines within the amyloid fibrils preventing their dissociation and seeding capacity.

Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative.

Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell)-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic) and B16F10 (immunogenic) cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT) and heat shock proteins (HSPs) was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC) uptake of dying tumor cells: the proportion of CRT+CD11c+cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

Sesquiterpene Quinones and Diterpenes from Smenospongia cerebriformis and Their Cytotoxic Activity.

Using various chromatographic methods, one new sesquiterpene quinone named smenohaimien F (1) and five known, neodactyloquinone (2), dactyloquinone C (3), dactyloquinone D (4), isoamijiol (5), and amijiol (6), were isolated from the marine sponge Smenospongia cerebriformis Duchassaing & Michelotti, 1864. Their structures were elucidated by ID-, 2D-NMR spectroscopic analysis, HR-ESI-MS, and by comparing with the NMR data reported in the literature. The cytotoxic activities of the all compounds were evaluated on five human cancer cell lines, LU-1, HL-60, SK-Mel-2, HepG-2, and MCF-7. Compound 4 was found to exhibit significant cytotoxic activities on all tested human cancer cell lines with IC50 values ranging from 0.7 to 1.6 µg/mL.