Shikonin-Loaded Hollow Fe-MOF Nanoparticles for Enhanced Microwave Thermal Therapy

Microwave (MW) thermal therapy has been widely used for the treatment of cancer in clinics, but it still shows limited efficacy and a high recurrence rate owing to non-selective heat delivery and thermo-resistance. Regulating glycolysis shows great promise to improve MW thermal therapy since glycolysis plays an important role in thermo-resistance, progression, metabolism, and recurrence. Herein, we developed a delivery nanosystem of shikonin (SK)-loaded and hyaluronic acid (HA)-modified hollow Fe-MOF (HFM), HFM@SK@HA, as an efficient glycolysis-meditated agent to improve the efficacy of MW thermal therapy. The HFM@SK@HA nanosystem shows a high SK loading capacity of 31.7 wt %. The loaded SK can be effectively released from the HFM@SK@HA under the stimulation of an acidic tumor microenvironment and MW irradiation, overcoming the intrinsically low solubility and severe toxicity of SK. We also find that the HFM@SK@HA can not only greatly improve the heating effect of MW in the tumor site but also mediate MW-enhancing dynamic therapy efficiency by catalyzing the endogenous H2O2 to generate reactive oxygen species (ROS). As such, the MW irradiation treatment in the presence of HFM@SK@HA in vitro enables a highly improved anti-tumor efficacy due to the combined effect of released SK and generated ROS on inhibiting glycolysis in cancer cells. Our in vivo experiments show that the tumor inhibition rate is up to 94.75% ± 3.63% with no obvious recurrence during the 2 weeks after treatment. This work provides a new strategy for improving the efficacy of MW thermal therapy.

The Renoprotective Effect of Shikonin in a Rat Model of Diabetic Kidney Disease

BACKGROUND

In diabetes mellitus, diabetic nephropathy (DN) is a typical complication and pivotal cause of chronic kidney disease. The DN disease burden is among the highest in the world and is associated with high morbidity, mortality, and disease burden. Safe and effective medications are urgently needed for the treatment of DN. Interest has been increasing in Shikonin, extracted from the naphthoquinone plant, particularly in determining its renal protective effect.

METHODS

In this study, we explored Shikonin's effects and potential mechanisms on a streptozotocin (STZ)-induced DN experimental model. An STZ-induced rat diabetic model was established, and the rats were treated with different doses of Shikonin (10/50 mg/kg) for 4 weeks. Blood, urine, and renal tissue samples were collected after the last administration. Renal tissues were examined to detect each group's physiologic, biochemical, histopathologic, and molecular changes.

RESULTS

The results showed that Shikonin administration could significantly alleviate the STZ-induced elevation of blood urea nitrogen, serum creatinine, urinary protein content, and renal pathologic injury. Furthermore, Shikonin significantly decreased oxidative stress, inflammation, and Toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor-κB expression levels in DN kidney tissues. Shikonin showed a dose-dependent effect, with the best outcome at 50 mg/kg.

CONCLUSION

Shikonin could effectively alleviate DN-related nephropathy damage and reveal the underlying pharmacologic mechanism. Based on the results, a Shikonin combination can be used in clinical treatment.

Chitosan derivatives functionalized dual ROS-responsive nanocarriers to enhance synergistic oxidation-chemotherapy

The efficient triggering of prodrug release has become a challengeable task for stimuli-responsive nanomedicine utilized in cancer therapy due to the subtle differences between normal and tumor tissues and heterogeneity. In this work, a dual ROS-responsive nanocarriers with the ability to self-regulate the ROS level was constructed, which could gradually respond to the endogenous ROS to achieve effective, hierarchical and specific drug release in cancer cells. In brief, DOX was conjugated with MSNs via thioketal bonds and loaded with β-Lapachone. TPP modified chitosan was then coated to fabricate nanocarriers for mitochondria-specific delivery. The resultant nanocarriers respond to the endogenous ROS and release Lap specifically in cancer cells. Subsequently, the released Lap self-regulated the ROS level, resulting in the specific DOX release and mitochondrial damage in situ, enhancing synergistic oxidation-chemotherapy. The tumor inhibition Ratio was achieved to 78.49%. The multi-functional platform provides a novel remote drug delivery system in vivo.

Rubioncolin C, a natural naphthohydroquinone dimer isolated from Rubia yunnanensis, inhibits the proliferation and metastasis by inducing ROS-mediated apoptotic and autophagic cell death in triple-negative breast cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Rubia yunnanensis Diels is a traditional Chinese medicine that has diverse pharmacological activities, including antituberculosis, antirheumatism and anticancers. Rubioncolin C (RC), a natural naphthohydroquinone dimer isolated from the roots and rhizomes of R. yunnanensis Diels, has shown potent antitumor activity. However, the antitumor activity and its potential mechanism of RC in triple-negative breast cancer (TNBC) cell lines remained unclear.

AIM OF THE STUDY

This study was aim to investigate the anti-proliferation and anti-metastasis activity as well as the potential mechanism of RC on triple-negative breast cancer cells in vitro and in vivo.

MATERIALS AND METHODS

The sulforhodamine B assay, colony formation assay and cell cycle analysis were used to determine the anti-proliferative activity of RC on TNBC. The anti-metastatic activity in vitro of RC was detected through the scratch wound assay, cell migration and invasion assays and gelatin zymography. The flow cytometry, JC-1, GFP-LC3B plasmid transfection, MDC, Lysotracker red and Carboxy-H₂DCFDA, DHE, and MitoSOX™ Red staining were performed to investigate the effect of RC on apoptosis, autophagy and ROS level. The apoptosis inhibitor, autophagy inhibitors and ROS inhibitors were used to further verify the antitumor mechanism of RC. The protein levels related with cell cycle, apoptosis, and autophagy were examined with western blotting. In addition, the anti-tumor activity of RC in vivo was assessed in an experimental metastatic model.

RESULTS

In the present study, RC suppressed the proliferation of TNBC cells in a time- and dose-dependent manner via regulating cell cycle. Further experiments showed that RC inhibited the migration and invasion of TNBC cells by downregulating MMPs and inhibiting EMT. Moreover, we demonstrated that RC induced obviously apoptotic and autophagic cell death, activated MAPK signaling pathway and inhibited mTOR/Akt/p70S6K and NF-κB signaling pathways. Furthermore, the excessive ROS was produced after treatment with RC. The antioxygen NAC and GSH could rescue the cell viability and reestablish the ability of cell metastasis, and inhibit the RC-induced apoptosis and autophagy. In a mice lung metastasis model of breast cancer, RC inhibited lung metastasis, and induced autophagy and apoptosis.

CONCLUSION

These findings clarified the antitumor mechanism of RC on TNBC cell lines and suggested that RC is a key active ingredient for the cancer treatment of R. yunnanensis, which would help RC develop as a new potential chemotherapeutic agent for TNBC treatment.

Connexin32 activates necroptosis through Src-mediated inhibition of caspase 8 in hepatocellular carcinoma

Necroptosis is an alternative form of programmed cell death that generally occurs under apoptosis-deficient conditions. Our previous work showed that connexin32 (Cx32) promotes the malignant progress of hepatocellular carcinoma (HCC) by enhancing the ability of resisting apoptosis in vivo and in vitro. Whether triggering necroptosis is a promising strategy to eliminate the apoptosis-resistant HCC cells with high Cx32 expression remains unknown. In this study, we found that Cx32 expression was positively correlated with the expression of necroptosis protein biomarkers in human HCC specimens, cell lines, and a xenograft model. Treatment with shikonin, a well-used necroptosis inducer, markedly caused necroptosis in HCC cells. Interestingly, overexpressed Cx32 exacerbated shikonin-induced necroptosis, but downregulation of Cx32 alleviated necroptosis in vitro and in vivo. Mechanistically, Cx32 was found to bind to Src and promote Src-mediated caspase 8 phosphorylation and inactivation, which ultimately reduced the activated caspase 8-mediated proteolysis of receptor-interacting serine-threonine protein kinase 1/3, the key molecule for necroptosis activation. In conclusion, we showed that Cx32 contributed to the activation of necroptosis in HCC cells through binding to Src and then mediating the inactivation of caspase 8. The present study suggested that necroptosis inducers could be more favorable than apoptosis inducers to eliminate HCC cells with high expression of Cx32.

Biogenic nanoporous silicon carrier improves the efficacy of buparvaquone against resistant visceral leishmaniasis

Visceral leishmaniasis is a vector-borne protozoan infection that is fatal if untreated. There is no vaccination against the disease, and the current chemotherapeutic agents are ineffective due to increased resistance and severe side effects. Buparvaquone is a potential drug against the leishmaniases, but it is highly hydrophobic resulting in poor bioavailability and low therapeutic efficacy. Herein, we loaded the drug into silicon nanoparticles produced from barley husk, which is an agricultural residue and widely available. The buparvaquone-loaded nanoparticles were several times more selective to kill the intracellular parasites being non-toxic to macrophages compared to the pure buparvaquone and other conventionally used anti-leishmanial agents. Furthermore, the in vivo results revealed that the intraperitoneally injected buparvaquone-loaded nanoparticles suppressed the parasite burden close to 100%. By contrast, pure buparvaquone suppressed the burden only by 50% with corresponding doses. As the conclusion, the biogenic silicon nanoparticles are promising carriers to significantly improve the therapeutic efficacy and selectivity of buparvaquone against resistant visceral leishmaniasis opening a new avenue for low-cost treatment against this neglected tropical disease threatening especially the poor people in developing nations.

Regression of Melanoma Following Intravenous Injection of Plumbagin Entrapped in Transferrin-Conjugated, Lipid-Polymer Hybrid Nanoparticles

BACKGROUND

Plumbagin, a naphthoquinone extracted from the officinal leadwort presenting promising anti-cancer properties, has its therapeutic potential limited by its inability to reach tumors in a specific way at a therapeutic concentration following systemic injection. The purpose of this study is to assess whether a novel tumor-targeted, lipid-polymer hybrid nanoparticle formulation of plumbagin would suppress the growth of B16-F10 melanoma in vitro and in vivo.

METHODS

Novel lipid-polymer hybrid nanoparticles entrapping plumbagin and conjugated with transferrin, whose receptors are present in abundance on many cancer cells, have been developed. Their cellular uptake, anti-proliferative and apoptosis efficacy were assessed on various cancer cell lines in vitro. Their therapeutic efficacy was evaluated in vivo after tail vein injection to mice bearing B16-F10 melanoma tumors.

RESULTS

The transferrin-bearing lipid-polymer hybrid nanoparticles loaded with plumbagin resulted in the disappearance of 40% of B16-F10 tumors and regression of 10% of the tumors following intravenous administration. They were well tolerated by the mice.

CONCLUSION

These therapeutic effects, therefore, make transferrin-bearing lipid-polymer hybrid nanoparticles entrapping plumbagin a highly promising anti-cancer nanomedicine.

Therapeutic approaches against coronaviruses acute respiratory syndrome

Coronaviruses represent global health threat. In this century, they have already caused two epidemics and one serious pandemic. Although, at present, there are no approved drugs and therapies for the treatment and prevention of human coronaviruses, several agents, FDA-approved, and preclinical, have shown in vitro and/or in vivo antiviral activity. An in-depth analysis of the current situation leads to the identification of several potential drugs that could have an impact on the fight against coronaviruses infections. In this review, we discuss the virology of human coronaviruses highlighting the main biological targets and summarize the current state-of-the-art of possible therapeutic options to inhibit coronaviruses infections. We mostly focus on FDA-approved and preclinical drugs targeting viral conserved elements.

Topical buparvaquone nano-enabled hydrogels for cutaneous leishmaniasis

Leishmaniasis is a neglected disease presenting cutaneous, mucosal and visceral forms and affecting an estimated 12 million mostly low-income people. Treatment of cutaneous leishmaniasis (CL) is recommended to expedite healing, reduce risk of scarring, prevent parasite dissemination to other mucocutaneous (common with New World species) or visceral forms and reduce the chance of relapse, but remains an unmet need. Available treatments are painful, prolonged (>20 days) and require hospitalisation, which increases the cost of therapy. Here we present the development of optimised topical self-nanoemulsifying drug delivery systems (SNEDDS) loaded with buparvaquone (BPQ, a hydroxynapthoquinone from the open Malaria Box) for the treatment of CL from New World species. The administration of topical BPQ-SNEDDS gels for 7 days resulted in a reduction of parasite load of 99.989 ± 0.019% similar to the decrease achieved with intralesionally administered Glucantime® (99.873 ± 0.204%) in a L. amazonensis BALB/c model. In vivo efficacy was supported by ex vivo permeability and in vivo tape stripping studies. BPQ-SNEDDS and their hydrogels demonstrated linear flux across non-infected CD-1 mouse skin ex vivo of 182.4 ± 63.0 μg cm^-2 h^-1 and 57.6 ± 10.8 μg cm^-2 h^-1 respectively localising BPQ within the skin in clinically effective concentrations (227.0 ± 45.9 μg and 103.8 ± 33.8 μg) respectively. These levels are therapeutic as BPQ-SNEDDS and their gels showed nanomolar in vitro efficacy against L. amazonensis and L. braziliensis amastigotes with excellent selectivity index toward parasites versus murine macrophages. In vivo tape stripping experiments indicated localisation of BPQ within the stratum corneum and dermis. Histology studies confirmed the reduction of parasitism and indicated healing in animals treated with BPQ-SNEDDS hydrogels. These results highlight the potential clinical capability of nano-enabled BPQ hydrogels towards a non-invasive treatment for CL.

Discovery of Isoplumbagin as a Novel NQO1 Substrate and Anti-Cancer Quinone

Isoplumbagin (5-hydroxy-3-methyl-1,4-naphthoquinone), a naturally occurring quinone from Lawsonia inermis and Plumbago europaea, has been reported to have anti-inflammatory and antimicrobial activity. Inflammation has long been implicated in cancer progression. In this study, we examined the anticancer effect of chemically synthesized isoplumbagin. Our results revealed that isoplumbagin treatment suppressed cell viability and invasion of highly invasive oral squamous cell carcinoma (OSCC) OC3-IV2 cells, glioblastoma U87 cells, non-small cell lung carcinoma H1299 cells, prostate cancer PC3 cells, and cervical cancer HeLa cells by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Boyden chamber assays. In vivo studies demonstrate the inhibitory effect of 2 mg/kg isoplumbagin on the growth of orthotopic xenograft tumors derived from OSCC cells. Mechanistically, isoplumbagin exerts its cytotoxic effect through acting as a substrate of reduced nicotinamide adenine dinucleotide phosphate [NAD(P)H] dehydrogenase quinone 1 (NQO1) to generate hydroquinone, which reverses mitochondrial fission phenotype, reduces mitochondrial complex IV activity, and thus compromises mitochondrial function. Collectively, this work reveals an anticancer activity of isoplumbagin mainly through modulating mitochondrial dynamics and function.

Phase 1 study of napabucasin, a cancer stemness inhibitor, in patients with advanced solid tumors

PURPOSE

Napabucasin is a cancer stemness inhibitor that targets a number of oncogenic pathways, including signal transducer and activator of transcription 3 (STAT3). Phase 1/2 studies suggest tolerability and anti-tumor activity in various types of cancer; a Phase 3 study of napabucasin plus standard therapy in colorectal cancer is ongoing. This is a Phase 1 dose-escalation study in patients with advanced solid tumors, and the first study of napabucasin in Japanese patients.

METHODS

Patients received napabucasin 480, 960, or 1440 mg daily in 28-day cycles until disease progression or intolerable toxicity. Primary objectives were to determine dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), and the pharmacokinetic (PK) profile of napabucasin. Blood samples were taken for PK analysis on Days 1, 2, 8, and 15 of Cycle 1, and Days 29 and 30 of Cycle 2. Secondary objectives were to assess napabucasin antitumor activity, and the relationship between biomarkers and antitumor activity. JapicCTI-No: JapicCTI-132152.

RESULTS

Enrolled were 14 patients (480 mg [n = 3], 960 mg [n = 4], 1440 mg [n = 7]). One patient experienced a DLT (Grade 3, anorexia). MTD was 1440 mg/day. Most common drug-related adverse events were diarrhea (n = 9), nausea (n = 4), vomiting (n = 3), and anorexia (n = 3). Napabucasin showed a similar PK profile to previous studies and no abnormal accumulation was observed. Following treatment, two patients had stable disease; the remaining 12 had progressive disease.

CONCLUSION

Napabucasin was well-tolerated at doses up to 1440 mg/day in Japanese patients with advanced solid tumors; the PK profile was comparable to that reported previously.

A natural anthraquinone derivative shikonin synergizes with AZD9291 against wtEGFR NSCLC cells through reactive oxygen species-mediated endoplasmic reticulum stress

BACKGROUND

NSCLC is the major type of lung cancer and the survival rates of NSCLC patients remain low. AZD9291 is a third-generation EGFR-TKI and approved to treat NSCLC patients harboring EGFR T790M mutation and common targetable activating EGFR mutations, but it has a limited effect for wtEGFR NSCLC.

PURPOSE

The current study investigated whether shikonin could enhance the antitumor effect of AZD9291 in wtEGFR NSCLC cells.

METHODS

SRB and colony formation assay were used to detect the proliferation of NSCLC cells, propidium iodide staining was performed to detect the apoptosis, ROS was analyzed using DCFH-DA staining, and western blot was used to detect the expression of indicated proteins.

RESULTS

We demonstrated that shikonin, a natural ROS inducer, could enhance the antitumor effect of AZD9291 in wtEGFR NSCLC cells. In addition, shikonin increased AZD9291-induced apoptosis accompanying with the generation of ROS and activation of ER stress. Furthermore, ROS inhibition by NAC or GSH reversed the apoptosis induced by shikonin plus AZD9291, and recovered the ER stress activated by combination treatment, indicating that ROS mediated ER stress played a vital role in this combination therapy. Moreover, shikonin increased the anticancer activity of AZD9291 in primary wtEGFR NSCLC cells through ROS-mediated ER stress.

CONCLUSION

Our study suggests that combining shikonin with AZD9291 is a promising therapeutic strategy for treating wtEGFR NSCLC patients.

The Protective Effect of Echinochrome A on Extracellular Matrix of Vocal Folds in Ovariectomized Rats

Here, we investigated the effects of sex hormones on extracellular matrix (ECM)-related gene expression in the vocal fold lamina propria of ovariectomized (after ovary removal) rats and verified whether echinochrome A (ECH) exerts any therapeutic effects on ECM reconstitution after estrogen deficiency in ovariectomized rats. Sprague–Dawley female rats (9 weeks old) were acclimatized for a week and randomly divided into three groups (n = 15 each group) as follows: group I (sham-operated rats, SHAM), group II (ovariectomized rats, OVX), group III (ovariectomized rats treated with ECH, OVX + ECH). Rats from the OVX + ECH group were intraperitoneally injected with ECH at 10 mg/kg thrice a week after surgery for 6 weeks. And rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in OVX group compared with the SHAM group. ECH treatment had no effect on the levels of estradiol and expression of estrogen receptor β (ERβ). The evaluation of ECM components showed no significant changes in elastin and hyaluronic acid levels between the different groups. Collagen I and III levels were lower in OVX group than in SHAM group but increased in OVX + ECH group. The mRNA levels of matrix metalloproteinase (MMP)-1, -2, -8, and -9 were significantly higher in the OVX group than in the SHAM group, but decreased in the OVX + ECH group. Thus, changes were observed in ECM-related genes in the OVX group upon estradiol deficiency that were ameliorated by ECH administration. Thus, the vocal fold is an estradiol-sensitive target organ and ECH may have protective effects on the ECM of vocal folds in ovariectomized rats.

The role of survivin in the progression of pancreatic ductal adenocarcinoma (PDAC) and a novel survivin-targeted therapeutic for PDAC

Treating pancreatic ductal adenocarcinoma (PDAC) remains a major hurdle in the field of oncology. Less than half of patients respond to frontline chemotherapy and the pancreatic tumor microenvironment limits the efficacy of immunotherapeutic approaches. Targeted therapies could serve as effective treatments to enhance the clinical response rate. One potential therapeutic target is survivin, a protein that is normally expressed during embryonic and fetal development and has a critical impact on cell cycle control and apoptosis. In adulthood, survivin is not present in most normal adult cells, but is significantly re-expressed in tumor tissues. In PDAC, elevated survivin expression is correlated with treatment resistance and lower patient survival, although the underlying mechanisms of survivin's action in this type of cancer is poorly understood. Using patient derived xenografts of PDAC and their corresponding primary pancreatic cancer lines (PPCL-46 and PPCL-LM1) possessing increased expression of survivin, we aimed to evaluate the therapeutic response of a novel survivin inhibitor, UFSHR, with respect to survivin expression and the tumorigenic characteristics of PDAC. Cell viability and apoptosis analyses revealed that repressing survivin expression by UFSHR or YM155, a well-known inhibitor of survivin, in PPCLs effectively reduces cell proliferation by inducing apoptosis. Tumor cell migration was also hindered following treatment with YM155 and UFSHR. In addition, both survivin inhibitors, particularly UFSHR, effectively reduced progression of PPCL-46 and PPCL-LM1 tumors, when compared to the untreated cohort. Overall, this study provides solid evidence to support the critical role of survivin in PDAC progression and proposes a novel survivin inhibitor UFSHR that can become an alternative strategy for this type of cancer.

A Phase I Study of Napabucasin Plus Paclitaxel for Japanese Patients With Advanced/Recurrent Gastric Cancer

AIM

To report results from the first phase I study of napabucasin plus paclitaxel in Japanese patients with pre-treated unresectable/recurrent gastric cancer.

PATIENTS AND METHODS

Patients received napabucasin (480 mg bid) plus paclitaxel [80 mg/m2 on days 3, 10 and 17 (cycles 1 and 2) and on days 1, 8 and 15 (cycle 3 and subsequent cycles)] until disease progression or unacceptable toxicity. Primary objectives were tolerability, safety and pharmacokinetics of napabucasin plus paclitaxel. Trial registration ID: JapicCTI-142420.

RESULTS

Six patients were enrolled. Paclitaxel had a minimal effect on napabucasin pharmacokinetics and median plasma paclitaxel concentrations were similar in combination and monotherapy. No dose-limiting toxicities were observed. There were no grade 4/5 adverse events. Partial response, stable disease and progressive disease were reported in two patients each.

CONCLUSION

Napabucasin plus paclitaxel was well-tolerated in Japanese patients with gastric cancer.

Plumbagin Increases Paclitaxel-Induced Cell Death and Overcomes Paclitaxel Resistance in Breast Cancer Cells through ERK-Mediated Apoptosis Induction

ERK is a component of mitogen-activated protein kinases that controls a range of cellular processes including cell proliferation and survival. The upregulation of ERK has been associated with apoptosis inhibition in response to various stimuli including chemotherapeutic agents. Research has suggested that the upregulation of ERK signaling by the anticancer agent paclitaxel leads to acquired resistance of cells to this compound. The presented research focused on determining the role of plumbagin, a naturally derived naphthoquinone, in the sensitization of breast cancer cells to paclitaxel-induced cell death and the involvement of ERK signaling in this process. The results of the study indicated that plumbagin increases the sensitivity of breast cancer cells to paclitaxel. Moreover, a synergistic effect between plumbagin and paclitaxel was observed. Plumbagin was shown to decrease levels of phosphorylated ERK in breast cancer cells and abrogated paclitaxel-induced ERK phosphorylation. The role of ERK in plumbagin-mediated sensitization of breast cancer cells to paclitaxel was shown through the enhancement of the synergistic effect between compounds in cells with decreased ERK expression. Furthermore, plumbagin reduced p-ERK levels in paclitaxel-resistant breast cancer cells and resensitized paclitaxel-resistant cells to this compound. These results imply that plumbagin inhibits ERK activation in breast cancer cells, which plays a role in the sensitization of cells to paclitaxel-induced cell death.

Application of Sustainable Natural Resources in Agriculture: Acaricidal and Enzyme Inhibitory Activities of Naphthoquinones and Their Analogs against Psoroptes cuniculi

As important secondary plant metabolites, naphthoquinones exhibit a wide range of biological activities. However, their potential as sustainable alternatives to synthetic acaricides has not been studied. This study for the first time investigates the acaricidal activity of naphthoquinones against Psoroptes cuniculi in vitro. Furthermore, the in vivo activity, the skin irritation effects, the cytotoxicity and the inhibitory activities against mite acetylcholinesterase (AChE) and glutathione S-transferase (GST) of the two compounds that displayed the best insecticidal activity in vitro were evaluated. Among fourteen naphthoquinones and their analogs, juglone and plumbagin were observed to possess the strongest acaricidal activities against P. cuniculi with LC50 values of 20.53 ppm and 17.96 ppm, respectively, at 24 h. After three treatments, these two chemicals completely cured naturally infested rabbits in vivo within 15 days, and no skin irritation was found in any of the treated rabbits. Compared to plumbagin, juglone presented no or weak cytotoxicity against HL-7702 cells. Moreover, these two chemicals significantly inhibited AChE and GST activity. These results indicate that juglone has promising toxicity against P. cuniculi, is safe for both humans and animals at certain doses, and could be used as a potential alternative bio-acaricide for controlling the development of psoroptic mange in agricultural applications.

EGFR-mediated interleukin enhancer-binding factor 3 contributes to formation and survival of cancer stem-like tumorspheres as a therapeutic target against EGFR-positive non-small cell lung cancer

OBJECTIVES

YM155, an inhibitor of interleukin enhancer-binding factor 3 (ILF3), significantly suppresses cancer stemness property, implying that ILF3 contributes to cell survival of cancer stem cells. However, the molecular function of ILF3 inhibiting cancer stemness remains unclear. This study aimed to uncover the potential function of ILF3 involving in cell survival of epidermal growth factor receptor (EGFR)-positive lung stem-like cancer, and to investigate the potential role to improve the efficacy of anti-EGFR therapeutics.

MATERIALS AND METHODS

The association of EGFR and ILF3 in expression and regulations was first investigated in this study. Lung cancer A549 cells with deprivation of ILF3 were created by the gene-knockdown method and then RNAseq was applied to identify the putative genes regulated by ILF3. Meanwhile, HCC827- and A549-derived cancer stem-like cells were used to investigate the role of ILF3 in the formation of cancer stem-like tumorspheres.

RESULTS

We found that EGFR induced ILF3 expression, and YM155 reduced EGFR expression. The knockdown of ILF3 reduced not only EGFR expression in mRNA and protein levels, but also cell proliferation in vitro and in vivo, demonstrating that ILF3 may play an important role in contributing to cancer cell survival. Moreover, the knockdown and inhibition of ILF3 by shRNA and YM155, respectively, reduced the formation and survival of HCC827- and A549-derived tumorspheres through inhibiting ErbB3 (HER3) expression, and synergized the therapeutic efficacy of afatinib, a tyrosine kinase inhibitor, against EGFR-positive A549 lung cells.

CONCLUSION

This study demonstrated that ILF3 plays an oncogenic like role in maintaining the EGFR-mediated cellular pathway, and can be a therapeutic target to improve the therapeutic efficacy of afatinib. Our results suggested that YM155, an ILF3 inhibitor, has the potential for utilization in cancer therapy against EGFR-positive lung cancers.

Plumbagin improves the efficacy of androgen deprivation therapy in prostate cancer: A pre-clinical study

BACKGROUND

Plumbagin is a candidate drug for the treatment of prostate cancer. Previous observations indicated that it may improve the efficacy of androgen deprivation therapy (ADT). This study evaluates the effectiveness of treatment with combinations of plumbagin and alternative strategies for ADT in mouse models of prostate cancer to support its clinical use.

METHODS

Plumbagin was administered per oral in a new sesame oil formulation. Standard toxicology studies were performed in rats. For tumor growth studies, mouse prostate cancer cell spheroids were placed on top of grafted prostate tissue in a dorsal chamber and allowed to form tumors. Mice were separated in various treatment groups and tumor size was measured over time by intra-vital microscopy. Survival studies were done in mice after injection of prostate cancer cells in the prostate of male animals. Androgen receptor (AR) levels were analyzed by Western blot from prostate cancer cells treated with plumbagin.

RESULTS

Plumbagin caused a decrease in AR levels in vitro. In mice, plumbagin at 1 mg/kg in sesame oil displayed low toxicity and caused a 50% tumor regression when combined with castration. The combination of plumbagin with various forms of chemical ADT including treatment with a GnRH receptor agonist, a GnRH receptor antagonist, or CYP17A1 inhibitors, outperformed ADT alone, increasing mouse survival compared to the standard regimen of castration alone. In contrast, the combination of plumbagin with AR antagonists, such as bicalutamide and enzalutamide, showed no improvement over AR antagonists alone. Thus, plumbagin is effective in combination with drugs that prevent the synthesis of testosterone or its conversion to dihydrotestosterone, but not with drugs that bind to AR.

CONCLUSION

Plumbagin significantly improves the effect of ADT drugs currently used in the clinic, with few side effects in mice.

Lactoferrin functionalized PEG-PLGA nanoparticles of shikonin for brain targeting therapy of glioma

Shikonin (SHK) is a highly liposoluble naphthoquinone pigment has recently been investigated as a potential antiglioma agent. However, shikonin shows several limitations like poor aqueous solubility, short half-life and non-selective biodistribution. Herein, we have developed a nanoparticles (NPs) prepared from PEG-PLGA using an emulsion solvent evaporation method. Nanoparticle surfaces were modified by coating with lactoferrin (Lf) to improve the crossing of the blood brain barrier and targeting of glioma cells via receptor-mediated path-ways. X-ray powder diffraction and differential scanning calorimetry analysis revealed the amorphous nature of SHK encapsulated within the NPs. Moreover, the drug-loaded NPs exhibit narrow size distribution and high encapsulation efficiency. The in vitro release experiments of the NPs exhibited sustained release for more than 72h. When compared to free SHK and SHK/NPs, in vivo study demonstrated higher brain concentration of SHK, indicating a significant effect of Lf coated NPs on brain targeting. Accordingly, these findings provide evidence for the potential of Lf-modified NPs as a targeted delivery system for brain glioblastomas treatment.

Development of a murine vertical transmission model for Toxoplasma gondii oocyst infection and studies on the efficacy of bumped kinase inhibitor (BKI)-1294 and the naphthoquinone buparvaquone against congenital toxoplasmosis

Objectives

Establishment of a mouse model for congenital toxoplasmosis based on oral infection with oocysts from Toxoplasma gondii ME49 and its application for investigating chemotherapeutic options against congenital toxoplasmosis.

Methods

CD1 mice were mated, orally infected with 5, 25, 100, 500 or 2000 oocysts and monitored for clinical signs and survival of dams and pups until 4 weeks post partum . The parasite burden in infected mice was quantified by real-time PCR in lungs, brains and, in the case of surviving pups, also in eyes. Seroconversion was assessed by ELISA. T. gondii cysts in brain were identified by immunofluorescence. In a second experiment, pregnant CD1 mice challenged with 20 oocysts/mouse were treated with buparvaquone or the calcium-dependent protein kinase 1 inhibitor bumped kinase inhibitor (BKI)-1294 and the outcome of infection was analysed.

Results

T. gondii DNA was detected in the brain of all infected animals, irrespective of the infection dose. Seroconversion occurred at 3 weeks post-infection. Most pups born to infected dams died within 1 week post partum , but a small fraction survived until the end of the experiment. T. gondii DNA was detected in the brain of all survivors and half of them exhibited ocular infection. Chemotherapy with both compounds led to dramatically increased numbers of surviving pups and reduced cerebral infection. Most efficient were treatments with BKI-1294, with 100% survivors and only 7% brain-positive pups.

Conclusions

BKI-1294 and buparvaquone exert excellent activities against transplacental transmission in pregnant mice.

Targeting Osteocytes to Attenuate Early Breast Cancer Bone Metastasis by Theranostic Upconversion Nanoparticles with Responsive Plumbagin Release

The early detection and thus treatment of breast cancer bone metastasis remain a big challenge clinically. As the most abundant cells within bone tissue, osteocytes have been found to manipulate the activity of early cancer bone metastasis by its crosstalk with cancer cells and osteoclasts. However, conventional bone-targeting nanomedicine has limited bone-lesion specificity and ignores the vital role of osteocytes during breast cancer bone metastasis. Also, it lacks detailed insight into the therapeutic mechanisms, which hinders the following translational practice. Previously, we have shown that a combination of zoledronic acid (ZA) and plumbagin (PL) synergistically alleviates cancer-induced bone destruction. Herein, we further develop a pH-responsive bone-targeting drug delivery system, i.e., the ZA-anchored bimodal mesoporous slica covered gadolinium(III) upconversion nanoparticles loaded with PL, to detect and treat bone metastasis sensitively and specifically at an early stage. This multifunctional nanosystem can target osteocytes to release PL as controlled by pH, decreasing osteocytic RANKL expression synergistically through the structural simulation of adenosine phosphate, which competitively inhibits the phosphorylation of osteocytic protein kinase-a, cAMP-response element binding protein, extracellular regulated protein kinase, and c-Jun N-terminal kinase. More importantly, by establishing a breast cancer bone metastasis mice model via intracardiac injection, we show that tumoriogenesis and osteoclastogenesis can both be attenuated significantly. We thereby realize the effective theranostics of tiny bone metastasis in breast cancer bone metastasis. Our work highlights the significance of theranostic nanomedicine and osteocyte-targeting therapy in the treatment of early bone metastasis, which could be applied in achieving efficient theranostic effects for other bone diseases.

Plumbagin-loaded aptamer-targeted poly D,L-lactic-co-glycolic acid-b-polyethylene glycol nanoparticles for prostate cancer therapy

Plumbagin inhibits the growth, metastasis, and invasion of prostate cancer (PCa). However, its lower bioavailability limits biopharmaceutical properties due to insolubility in water. Prostate-specific membrane antigen (PSMA) aptamer-targeted nanoparticles (NPs) significantly enhanced cytotoxicity in prostate epithelial cells. This study aimed to investigate the effects of plumbagin-loaded prostate-specific membrane antigen (PSMA) aptamer-targeted poly D,L-lactic-co-glycolic acid-b-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) on prostate cancer (PCa) in vitro.PLGA-PEG with a terminal carboxylic acid group (PLGA-PEG-COOH) was synthesized, and plumbagin was loaded on PLGA-PEG-COOH NPs using the nanoprecipitation method and characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser light scattering. The uptake and distribution of plumbagin-NPs in human PCa LNCaP cells were investigated by fluorescent labeling. Subsequently, PSMA antibody-targeted PLGA-PEG-COOH NPs (targeted NPs) were prepared by covalent binding and characterized by x-ray photoelectron spectroscopy. Furthermore, the anticancer activity of plumbagin-loaded, targeted NPs was compared with that of nontargeted NPs in LNCaP cells in vitro.Plumbagin-NPs (diameter of 189.4 ± 30.6 nm and zeta potential of -17.1 ± 3.7 mV) were optimized based on theoretical drug loading of 5% and a ratio of water:acetone of 3:1. During the first 2 hours, the cumulative release rate of the drug was 66.4 ± 8.56%. Moreover, plumbagin-targeted NPs with nitrogen atoms were prepared. The uptake rate was 90% at 0.5 hours for targeted and nontargeted NPs. The IC50 of targeted NPs and nontargeted NPs was 32.59 ± 8.03 μM and 39.02 ± 7.64 μM, respectively.Plumbagin-loaded PSMA aptamer-targeted NPs can be used in targeted chemotherapy against PCa.

FORMULATION AND ASSESSMENT OF SEMI-SOLID CARRIER INCORPORATED WITH HERBAL EXTRACT OF LAWSONIA INERMIS

The development of an optimal microemulsion of lawsone for transdermal delivery was the core objective of the study. Effects of formulation variable including oils, surfactants and co-surfactants on the per- cutaneous delivery of lawsone microemulsion have also been inspected. Pseudotemary phase diagrams with oil, cosurfactant-surfactant mixtures (Smix) were constructed to recognize the microemulsion areas. Microemulsion prepared was of 5%. The in vitro transdermal penetration of microemulsion of lawsone was determined by Franz diffusion cell. These profiles indicated that the absorption and rate of penetration of lawsone microemul- sion was far better than the saturated solution of lawsone. The formulation was characterized for pH, conduc- tivity, viscosity and passed stability tests. A non-irritant formulation to skin was prepared in this way. The out- comes specify that the transdermal drug delivery ability and phase behavior of microemulsion is affected by the type of cosurfactant and surfactant.

1,4-Naphthoquinone activates the HSP90/HSF1 pathway through the S-arylation of HSP90 in A431 cells: Negative regulation of the redox signal transduction pathway by persulfides/polysulfides

The current consensus is that environmental electrophiles activate redox signal transduction pathways through covalent modification of sensor proteins with reactive thiol groups at low concentrations, while they cause cell damage at higher concentrations. We previously exposed human carcinoma A431 cells to the atmospheric electrophile 1,4-naphthoquinone (1,4-NQ) and found that heat shock protein 90 (HSP90), a negative regulator of heat shock factor 1 (HSF1), was a target of 1,4-NQ. In the study presented here, we determined whether 1,4-NQ activates HSF1. We also examined whether such redox signaling could be regulated by nucleophilic sulfur species. Exposure of A431 cells to 1,4-NQ covalently modified cellular HSP90, resulting in repression of the association between HSF1 with HSP90, thereby enhancing HSF1 translocation into the nuclei. Liquid chromatography-tandem mass spectrometry analysis with recombinant HSP90 revealed that the modifications site were Cys412 and Cys564. We found that HSF1 activation mediated by 1,4-NQ upregulated downstream genes, such as HSPA6. HSF1 knockdown accelerated 1,4-NQ-mediated cytotoxicity in the cells. While simultaneous treatment with reactive persulfide and polysulfide, Na₂S₂ and Na₂S₄, blocked 1,4-NQ-dependent protein modification and HSF1 activation in A431 cells, the knockdown of Cys persulfide producing enzymes cystathionine β-synthase (CBS) and/or cystathionine γ-lyase (CSE) enhanced these phenomena. 1,4-NQ-thiol adduct and 1,4-NQ-S-1,4-NQ adduct were produced during the enzymatic reaction of recombinant CSE in the presence of 1,4-NQ. The results suggest that activation of the HSP90-HSF1 signal transduction pathway mediated by 1,4-NQ protects cells against 1,4-NQ and that per/polysulfides can diminish the reactivity of 1,4-NQ by forming sulfur adducts.

Sensitizing effect of juglone is mediated by down regulation of Notch1 signaling pathway in trastuzumab-resistant SKBR3 cells

Trastuzumab (Herceptin) monoclonal antibody directed against HER2 receptor has been administered as a treatment for metastatic HER2 positive breast cancer. The problematic issue in treatment of HER2 positive breast cancer cells is commonly the induction of resistance to trastuzumab which might be due to modulation of some vital signaling elements such as Notch1 and Pin1. In this study, we were aimed to investigate whether the cross talk between pin1 and Notch1 has a role in this event. Our results indicated that the expression level of Pin1 in resistant SKBR3 cells increased by about twofold relative to sensitive SKBR3 cells. Besides, Pin1 inhibition via juglone reduced the extent of proliferation, colony formation and migration capacity of resistant SKBR3 cells. In addition, despite a feed forward loop between Notch1 and Pin1 in sensitive SKBR3 cells, inhibition of Notch1 cleavage in resistant SKBR3 cells did not affect pin1 level whereas pin1 inhibition by juglone reduced the level of Hes1, p-Akt and increased the cellular content of Numb. Therefore, we concluded that pin1 inhibition could be considered as a promising sensitizing strategy to weaken trastuzumab resistance.

Leveraging an NQO1 Bioactivatable Drug for Tumor-Selective Use of Poly(ADP-ribose) Polymerase Inhibitors

Therapeutic drugs that block DNA repair, including poly(ADP-ribose) polymerase (PARP) inhibitors, fail due to lack of tumor-selectivity. When PARP inhibitors and β-lapachone are combined, synergistic antitumor activity results from sustained NAD(P)H levels that refuel NQO1-dependent futile redox drug recycling. Significant oxygen-consumption-rate/reactive oxygen species cause dramatic DNA lesion increases that are not repaired due to PARP inhibition. In NQO1⁺ cancers, such as non-small-cell lung, pancreatic, and breast cancers, cell death mechanism switches from PARP1 hyperactivation-mediated programmed necrosis with β-lapachone monotherapy to synergistic tumor-selective, caspase-dependent apoptosis with PARP inhibitors and β-lapachone. Synergistic antitumor efficacy and prolonged survival were noted in human orthotopic pancreatic and non-small-cell lung xenograft models, expanding use and efficacy of PARP inhibitors for human cancer therapy.

β-Lapachone increases phase II antioxidant enzyme expression via NQO1-AMPK/PI3K-Nrf2/ARE signaling in rat primary astrocytes

β-Lapachone (β-LAP) is a naturally occurring quinine that exerts a number of pharmacological actions including antibacterial, antifungal, antimalarial, and antitumor activities. In the present study, we investigated whether β-LAP has an antioxidant effect in rat primary astrocytes. β-LAP suppressed intracellular reactive oxygen species (ROS) production induced by hydrogen peroxide and inhibited astroglial cell death. It also increased astrocytic expression of phase II antioxidant enzymes such as heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), manganese superoxide dismutase (MnSOD), and catalase. Further mechanistic studies revealed that β-LAP activated AMPK and Akt, and pretreatment of cells with an AMPK inhibitor (compound C) or PI3K/Akt inhibitor (LY294002) suppressed β-LAP-induced antioxidant enzyme expression by inhibiting Nrf2/antioxidant response element (ARE) signaling. Compound C also decreased Akt phosphorylation, suggesting that AMPK is upstream of PI3K/Akt. Furthermore, the AMPK activator 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside mimicked the effect of β-LAP by increasing Akt phosphorylation and ARE-mediated transcription, suggesting that AMPK plays a pivotal role in β-LAP-mediated antioxidant enzyme expression. Because β-LAP effects are usually associated with NQO1 activity, we examined the effect of NQO1 knockdown on antioxidant enzyme expression. Small interfering RNA (siRNA) specific for NQO1 inhibited β-LAP-induced AMPK/Akt phosphorylation and downstream antioxidant enzyme expression. Collectively, the results suggest that β-LAP increases antioxidant enzyme gene expression in astrocytes by modulating NQO1-AMPK/PI3K-Nrf2/ARE signaling.

2-Methoxy-6-acetyl-7-methyljuglone (MAM), a natural naphthoquinone, induces NO-dependent apoptosis and necroptosis by H2O2-dependent JNK activation in cancer cells

Redox signaling plays a fundamental role in maintaining cell physiological activities. A deregulation of this balance through oxidative stress or nitrosative stress has been implicated in cancer. Here, we reported that 2-methoxy-6-acetyl-7-methyl juglone (MAM), a natural naphthoquinone isolated from Polygonum cuspidatum Sieb. et Zucc, caused hydrogen peroxide (H2O2) dependent activation of JNK and induced the expression of inducible nitric oxide synthase (iNOS), thereby leading to nitric oxide (NO) generation in multiple cancer cells. Nitrosative stress induced necroptosis in A549 lung cancer cells, but resulted in caspase-dependent intrinsic apoptosis in B16-F10 melanoma and MCF7 breast cancer cells. In addition, a decrease in GSH/GSSG levels accompanied with increased ROS production was observed. Reversal of ROS generation and cell death in GSH pretreated cells indicated the involvement of GSH depletion in MAM mediated cytotoxicity. In summary, a natural product MAM induced NO-dependent multiple forms of cell death in cancer cells mediated by H2O2-dependent JNK activation in cancer cells. GSH depletion might play an initial role in MAM-induced cytotoxicity.

Small molecule inhibitor YM155-mediated activation of death receptor 5 is crucial for chemotherapy-induced apoptosis in pancreatic carcinoma

Despite much effort, pancreatic cancer survival rates are still dismally low. Novel therapeutics may hold the key to improving survival. YM155 is a small molecule inhibitor that has shown antitumor activity in a number of cancers by reducing the expression of survivin. The aim of our study is to understand the mechanisms by which YM155 functions in pancreatic cancer cells. We established the antitumor effect of YM155 with in vitro studies in cultured cells, and in vivo studies using a mouse xenograft model. Our data demonstrated that YM155 reduced the expression of survivin; however, downregulation of survivin itself is insufficient to induce apoptosis in pancreatic cancer cells. We showed for the first time that treatment with YM155 increased death receptor 5 (DR5) expression in pancreatic cancer cells. We found that YM155 induced apoptosis by broad-spectrum inhibition of IAP family member proteins (e.g., CIAP1/2 and FLIP) and induced proapoptotic Bak protein upregulation and activation; the antitumor effect of YM155 treatment with either the DR5 agonist lexatumumab or gemcitabine on pancreatic cancer cells was synergistic. Our data also revealed that YM155 inhibits tumor growth in vivo, without apparent toxicity to the noncancerous human pancreatic ductal epithelial cell line. Together, these findings suggest that YM155 could be a novel therapeutic agent for pancreatic cancer.

Formulation design and evaluation of liposomal sepantronium bromide (YM155), a small-molecule survivin suppressant, based on pharmacokinetic modeling and simulation

PURPOSE

Sepantronium bromide (YM155) is administered by 168-hour continuous infusions in clinical studies due to its time-dependent pharmacological efficacy and rapid elimination from plasma. To enable more convenient administration, i.e., bolus injections with low frequency, we prepared liposomal formulations of YM155 and evaluated their antitumor activities.

METHODS

A kinetic simulation model of liposomal YM155 to predict the free drug concentration in both tumor and plasma was developed. A liposomal formulation with the target drug release rate was prepared based on the simulation. Antitumor activities of the formulation were examined in various tumor xenograft mouse models. In addition, antitumor activities of liposomal formulations with different drug release rates were compared in order to confirm the validity of the simulation-based prediction.

RESULTS

Liposomal YM155 with the release half-life of 48 h was prepared as a promising formulation. This formulation showed significantly potent antitumor activities in tumor xenograft models by weekly bolus injections. Further studies demonstrated that this release rate was optimal for YM155 in terms of both efficacy and safety.

CONCLUSIONS

We successfully developed a liposomal formulation of YM155 that could substitute for long-term continuous infusion of the drug solution in clinical settings by being given as weekly bolus injections.

Synergistic antitumor activities of sepantronium bromide (YM155), a survivin suppressant, in combination with microtubule-targeting agents in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) has a poor prognosis compared to other subtypes, and effective treatment options are limited to cytotoxic agents, including microtubule-targeting agents, due to the lack of molecular targets. Here, we examined the combined effect of sepantronium bromide (YM155) and microtubule-targeting agents in TNBC models. The combination of YM155 with docetaxel showed synergistic antiproliferative and caspase 3/7-inducing effects in MRK-nu-1 and MDA-MB-453 human TNBC cell lines in vitro. YM155 also synergistically enhanced the efficacies of other microtubule-targeting agents, including paclitaxel and vinorelbine, which induced accumulation of survivin at the G2/M phase, whereas it did not affect the efficacy of doxorubicin. Combination treatment with YM155 and microtubule-targeting agents decreased the accumulation of survivin at the G2/M phase and induced greater apoptosis than either single agent alone. Further, combination treatment with YM155 and docetaxel also had a synergistic antitumor effect, achieving complete regression without exacerbation of body weight loss in all mice, in a MRK-nu-1 human TNBC xenograft model. These results suggest that survivin inhibition synergistically sensitize human TNBC cells to microtubule-targeting agents.

Shikonin targets cytosolic thioredoxin reductase to induce ROS-mediated apoptosis in human promyelocytic leukemia HL-60 cells

Shikonin, a major active component of the Chinese herbal plant Lithospermum erythrorhizon, has been applied for centuries in traditional Chinese medicine. Although shikonin demonstrates potent anticancer efficacy in numerous types of human cancer cells, the cellular targets of shikonin have not been fully defined. We report here that shikonin may interact with the cytosolic thioredoxin reductase (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme with a C-terminal -Gly-Cys-Sec-Gly active site, to induce reactive oxygen species (ROS)-mediated apoptosis in human promyelocytic leukemia HL-60 cells. Shikonin primarily targets the Sec residue in TrxR1 to inhibit its physiological function, but further shifts the enzyme to an NADPH oxidase to generate superoxide anions, which leads to accumulation of ROS and collapse of the intracellular redox balance. Importantly, overexpression of functional TrxR1 attenuates the cytotoxicity of shikonin, whereas knockdown of TrxR1 sensitizes cells to shikonin treatment. Targeting TrxR1 with shikonin thus discloses a previously unrecognized mechanism underlying the biological activity of shikonin and provides an in-depth insight into the action of shikonin in the treatment of cancer.

Response of Merkel cell polyomavirus-positive merkel cell carcinoma xenografts to a survivin inhibitor

Merkel cell carcinoma (MCC) is a neuroendocrine skin cancer associated with high mortality. Merkel cell polyomavirus (MCV), discovered in 2008, is associated with ~80% of MCC. The MCV large tumor (LT) oncoprotein upregulates the cellular oncoprotein survivin through its conserved retinoblastoma protein-binding motif. We confirm here that YM155, a survivin suppressor, is cytotoxic to MCV-positive MCC cells in vitro at nanomolar levels. Mouse survival was significantly improved for NOD-Scid-Gamma mice treated with YM155 in a dose and duration dependent manner for 3 of 4 MCV-positive MCC xenografts. One MCV-positive MCC xenograft (MS-1) failed to significantly respond to YM155, which corresponds with in vitro dose-response activity. Combination treatment of YM155 with other chemotherapeutics resulted in additive but not synergistic cell killing of MCC cell lines in vitro. These results suggest that survivin targeting is a promising therapeutic approach for most but not all MCV-positive MCCs.

Silencing of survivin using YM155 induces apoptosis and chemosensitization in neuroblastomas cells

OBJECTIVES

Aggressive cell growth and chemoresistance are notorious obstacles in neuroblastoma therapy. Accumulating evidence suggests that survivin is preferentially expressed in cancer cells and plays a crucial role in cell division and apoptosis dysfunction. Thus, in the present study, we investigated whether silencing of survivin, using a novel small-molecule survivin suppressant, YM155 could suppress the proliferation and induce chemosensitization of neuroblastoma cells.

MATERIALS AND METHODS

SH-SY5Y human neuroblastomas cells were treated with YM155 (10 to 500 mM) and/or chemotherapeutic agent cisplatin for 72 hours, and cell viability, apoptosis, mRNA and protein expression level were then evaluated. Furthermore, the efficacy of YM155 combined with cisplatin was further examined in established xenograft models.

RESULTS

YM155 suppressed expression of survivin, inhibited the proliferation and induced apoptosis in SH-SY5Y cells in a concentration-dependent manner. Reduced levels of survivin sensitized SH-SY5Y to the chemotherapeutic agent cisplatin. YM155 showed antiproliferative effects and induced tumor regression and apoptosis in established SH-SY5Y xenograft models. Cisplatin showed antitumor activity against SH-SY5Y cells, it did not induce survivin upregulation. Combination treatment of YM155 and cisplatin induced a greater rate of apoptosis than the sum of the single-treatment rates and promoted tumor regression without enhanced body weight loss in the SH-SY5Y xenograft models.

CONCLUSIONS

The concomitant combination of YM155 with cisplatin induced more intense apoptosis compared with each single treatment in vivo and in vitro. YM155 in combination with cisplatin is well tolerated and shows greater efficacy than either agent alone in mouse xenograft models.

Anti-angiogenic activity of salvicine

CONTEXT

Salvicine is a pharmacologically active derivative from Chinese medicinal plant Salvia prionitis Hance (Labiatae). It has been reported that salvicine inactivates β1 integrin and inhibits integrin-mediated cell adhesion to fibronectin. Given the emerging correlation between integrins and angiogenesis, we propose that salvicine abolishes cell adhesion and subsequent metastasis by inhibiting angiogenisis.

OBJECTIVE

The anti-angiogenesis activities of salvicine were investigated for the first time.

MATERIALS AND METHODS

The cytotoxicity of salvicine on human microvascular endothelial cells (HMECs) and non-small cell lung adenocarcinoma A549 cells were measured at doses between 0.625 and 200 µM. Changes of cell migration were detected with doses of salvicine at 1.25-5 µM, and basement membrane matrigel matrix was used for the assessment of tube formation at concentrations ranging from 0.078 to 1.25 µM. In addition, mRNA expression of basic fibroblast growth factor (bFGF) in A549 cells was studied with the RT-PCR assay.

RESULTS

In vitro studies revealed that the IC50 of salvicine on A549 cells (18.66 µM) was two-fold higher than that of HMECs (7.91 µM). Salvicine (1.25, 2.5 and 5.0 μM) inhibited significantly the endothelial cell migration up to 56, 73 and 82%, respectively. Salvicine decreased capillary-like tube formation of HMECs with high potency. Furthermore, it (30 µM) markedly reduced the mRNA expression of bFGF in A549 cells, while vascular endothelial growth factor (VEGF) mRNA expression remained unchanged.

DISCUSSION AND CONCLUSION

Our results suggest that salvicine has potent anti-angiogenic activity through the inhibition on the sequential angiogenic cascades: proliferation, migration and tube formation and is associated with influence on the expression of bFGF of tumor cell.

Induction of death of leukemia cells by TW-74, a novel derivative of chloro-naphthoquinone

We have previously shown that a 2-chloro-1,4-naphthoquinone derivative (TW-92) induces cell death in leukemia cells. TW-92 exhibited relatively high selectivity towards primary Acute Myeloid Leukemia (AML) cells, as compared to normal mononuclear cells. In view of the selectivity of this family of naphthoquinones, novel chloroaminophenylnaphthoquinone isomers with different methyl substitutions on the phenyl ring were synthesized, and their effect on leukemia cells was tested. These compounds induced cell death in U937 human myeloid leukemia cells, which was prominent following 48 h of culture. Structure-activity relationship studies revealed that TW-74, a novel chloronaphthoquinone with a methyl group at the meta (m) position, was the most active derivative in inducing apoptosis. The mechanism underlying cell death induction by TW-74 was further investigated in U937 cells, a monocytic cell line which serves as a sensitive model of apoptosis induction. TW-74 induced rapid activation of Mitogen Activated Protein Kinases (MAPKs). It caused swelling of isolated rat liver mitochondria and an early reduction of mitochondrial membrane potential in intact cells, indicative of a direct effect on mitochondria. Apoptosis induced by TW-74 was accompanied by cytochrome C release and caspase activation. TW-74 induced down- regulation of (BCL2), an anti-apoptotic protein. Furthermore, TW-74 induced selective dose-dependent cell death in primary B-Chronic Lymphocytic Leukemia (CLL) cells. These findings demonstrate that chloronaphthoquiniones use common as well as diverse mechanisms for the induction of cell death. The data reported here warrant further studies of the utility of TW-74 in the treatment of CLL.

[The mechanism of alteronol inhibiting the proliferation of human promyelocytic leukemia HL-60 cells]

This study is to investigate the mechanism of human promyelocytic leukemia HL-60 cells proliferation induced by alteronol in vitro. Human promyelocytic leukemia HL-60 cells cultured in vitro were treated with different concentrations of alteronol. Inhibition rate was detected by SRB assay. Cellular morphological changes were observed by Hoechst and AO/EB (acridine orange/ethidium bromide dye) staining. The apoptosis rate was determined by Annexin V-FITC/PI assay. Cell cycle distribution was determined by flow cytometry. Western blotting analysis was carried out to determine the cell cycle related proteins. The proliferation of HL-60 cells treated with alteronol was inhibited in a concentration-dependent manner. Based on cell viability assay, observation on cell morphology and apoptosis rate, it confirmed that alteronol played an obvious role in proliferation inhibition of human promyelocytic leukemia HL-60 cells, but it did not induce apoptosis in human promyelocytic leukemia HL-60 cells in different concentrations groups. Alteronol could effectively inhibit the proliferation of human promyelocytic leukemia HL-60 cells inducing cell cycle arrest at G1 phase, as well as, alteration expression of cell cycle proteins level of CyclinD1 and pRb.

Shikonin induces immunogenic cell death in tumor cells and enhances dendritic cell-based cancer vaccine

Immunogenic cell death is characterized by damage-associated molecular patterns, which can enhance the maturation and antigen uptake of dendritic cells. Shikonin, an anti-inflammatory and antitumor phytochemical, was exploited here as an adjuvant for dendritic cell-based cancer vaccines via induction of immunogenic cell death. Shikonin can effectively activate both receptor- and mitochondria-mediated apoptosis and increase the expression of all five tested damage-associated molecular patterns in the resultant tumor cell lysates. The combination treatment with damage-associated molecular patterns and LPS activates dendritic cells to a high maturation status and enhances the priming of Th1/Th17 effector cells. Shikonin-tumor cell lysate-loaded mature dendritic cells exhibit a high level of CD86 and MHC class II and activate Th1 cells. The shikonin-tumor cell lysate-loaded dendritic cell vaccines result in a strong induction of cytotoxic activity of splenocytes against target tumor cells, a retardation in tumor growth, and an increase in the survival of test mice. The much enhanced immunogenicity and efficacy of the current cancer vaccine formulation, that is, the use of shikonin-treated tumor cells as cell lysates for the pulse of dendritic cells in culture, may suggest a new ex vivo approach for developing individualized, dendritic cells-based anticancer vaccines.

YM155 induces EGFR suppression in pancreatic cancer cells

YM155, which inhibits the anti-apoptotic protein survivin, is known to exert anti-tumor effects in various cancers, including prostate and lung cancer. However, there are few reports describing the inhibitory effect of YM155 on human pancreatic cancers that highly express survivin. Here, we tested the effects of YM155 on a variety of cancer cell lines, including pancreatic cancer cells. We found that YM155 exerts an anti-proliferative effect in pancreatic cancer cells, inducing cell death through suppression of XIAP (X-linked inhibitor of apoptosis) as well as survivin without affecting the anti-apoptotic proteins Bcl-xL or Mcl-1. YM155 also inhibited tumor growth in vivo, reducing the size of pancreatic cancer cell line MIAPaCa-2 xenografts by 77.1% on day 31. Western blot analyses further showed that YM155 downregulated phosphoinoside 3-kinase (PI3K) expression and reduced the levels of phosphorylated (activated) extracellular signal-regulated kinase (ERK) and STAT3 (signal transducer and activator of transcription 3) in PANC-1 cells. Interestingly, we also found that YM155 downregulated the epidermal growth factor receptor (EGFR) in various cancer cell lines and induced the EGFR phosphorylation and ubiquitination of EGFR in PANC-1 cells. YM155 also modestly promoted the ubiquitination of survivin and XIAP. Therefore, YM155 acts through modulation of EGFR and survivin expression to subsequently reduce survival. We suggest that YM155 has potential as a therapeutic agent in the treatment of pancreatic cancer.

[Enhancing the immunogenic activity of influvac vaccine in the use of adjuvant TI complexes modified by echinochrome A]

The self-assembly of marine macrophyte glycolipids, holothurian saponin, and cholesterol gave rise to nanoscale morphological structures called tubular immunostimulating (TI) complexes. Whether the latter could be used on the basis of vaccine preparations containing the influenza virus subunit antigens was studied. There was an obvious increase in the immunogenicity of influenza virus hemagglutinin when the experimental animals were immunized with this antigen as part of TI complexes. It was shown that the adjuvant activity of the TI complex to influenza virus hemagglutinin could be enhanced by adding the known antioxidant echinochrome A from a sand-dollar (Echinarachnius parma) to the matrix of the TI complex.

Shikonin increases glucose uptake in skeletal muscle cells and improves plasma glucose levels in diabetic Goto-Kakizaki rats

BACKGROUND

There is considerable interest in identifying compounds that can improve glucose homeostasis. Skeletal muscle, due to its large mass, is the principal organ for glucose disposal in the body and we have investigated here if shikonin, a naphthoquinone derived from the Chinese plant Lithospermum erythrorhizon, increases glucose uptake in skeletal muscle cells.

METHODOLOGY/PRINCIPAL FINDINGS

Shikonin increases glucose uptake in L6 skeletal muscle myotubes, but does not phosphorylate Akt, indicating that in skeletal muscle cells its effect is medaited via a pathway distinct from that used for insulin-stimulated uptake. Furthermore we find no evidence for the involvement of AMP-activated protein kinase in shikonin induced glucose uptake. Shikonin increases the intracellular levels of calcium in these cells and this increase is necessary for shikonin-mediated glucose uptake. Furthermore, we found that shikonin stimulated the translocation of GLUT4 from intracellular vesicles to the cell surface in L6 myoblasts. The beneficial effect of shikonin on glucose uptake was investigated in vivo by measuring plasma glucose levels and insulin sensitivity in spontaneously diabetic Goto-Kakizaki rats. Treatment with shikonin (10 mg/kg intraperitoneally) once daily for 4 days significantly decreased plasma glucose levels. In an insulin sensitivity test (s.c. injection of 0.5 U/kg insulin), plasma glucose levels were significantly lower in the shikonin-treated rats. In conclusion, shikonin increases glucose uptake in muscle cells via an insulin-independent pathway dependent on calcium.

CONCLUSIONS/SIGNIFICANCE

Shikonin increases glucose uptake in skeletal muscle cells via an insulin-independent pathway dependent on calcium. The beneficial effects of shikonin on glucose metabolism, both in vitro and in vivo, show that the compound possesses properties that make it of considerable interest for developing novel treatment of type 2 diabetes.

A new naphthoquinone isolated from the bulbs of Cipura paludosa and pharmacological activity of two main constituents

Cipura paludosa (Iridaceae) is a plant that is distributed in the north region of Brazil. Its bulbs are used in folk medicine to treat inflammation and pain. Four naphthalene derivatives have been isolated from the bulbs of this plant. Three of them have been identified as the known naphthalene derivatives, eleutherine, iso-eleutherine, and hongkonin. The structure of the fourth and new component was determined as 11-hydroxyeleutherine by extensive NMR study. In addition, the IN VIVO effect of the two major compounds, eleutherine and iso-eleutherine, was evaluated in carrageenan-induced hypernociception and inflammation in mice. Eleutherine and iso-eleutherine (1.04-34.92 µmol/kg), dosed intraperitoneally (i.p.) or orally (p.o.), decreased the carrageenan-induced paw oedema (i.p. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively; p.o. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively). Iso-eleutherine, but not eleutherine, significantly reduced (inhibitions of 39 ± 4 %) the plasma extravasation induced by intradermal (i.d.) injection of carrageenan. Likewise, eleutherine and iso-eleutherine (1.04-34.92 µmol/kg, i.p. or p.o.) were also effective in preventing the carrageenan-induced hypernociceptive response (i.p. - inhibition of 59 ± 4 % and 63 ± 1 %, respectively; p.o. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively). It was also suggested that the anti-inflammatory and anti-hypernociceptive effects of eleutherine or iso-eleutherine partly depend on the interference with the synthesis or activity of mast cell products, kinins, cytokine, chemokines, prostanoids, or sympathetic amines. Our findings show that two major compounds of C. paludosa contain pharmacologically active constituents that possess antinociceptive and anti-inflammatory activity, justifying, at least in part, its popular therapeutic use for treating conditions associated with pain.

The anti-proliferation effect of Aikete injection on hepatocellular carcinoma in vitro and in vivo

CONTEXT

Aikete injection is composed of acetylshikonin and β,β-dimethylacrylshikonin, which have been reported to have anti-tumor effects on a wide range of cancer cell lines. However, little is known about the effects of the combination of the two components on cancer cells.

OBJECTIVE

To investigate the anti-proliferation activity of Aikete injection on human hepatocellular carcinoma (HCC) cells and its mechanism.

MATERIALS AND METHODS

3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and growth curve assay were used to determine the inhibitory effect of Aikete injection on the proliferation of SMMC-7721 cells. Giemsa staining, Hoechst 33258 staining and flow cytometry were used to assess cell apoptosis. Expression of Bcl-2 and Bax was analyzed by reverse transcription-polymerase chain reaction and flow cytometry. H22 bearing mice were also used to determine the anti-tumor effect of Aikete injection in vivo.

RESULTS

Aikete injection inhibited the proliferation of SMMC-7721 cells in both a dose- and time-dependent manner in vitro. The characteristics of apoptosis were observed in Aikete injection groups by Hoechst 33258 and Giemsa staining. In addition, Aikete injection induced cell cycle arrest at G2/M phase and downregulated the Bcl-2 expression and the ratio of Bcl-2/Bax in SMMC-7721 cells. The experiment in vivo showed that Aikete injection significantly inhibited the growth of H22 carcinoma, with an inhibitory rate of 34.37-57.99%.

DISCUSSION AND CONCLUSION

The results demonstrated that Aikete injection suppressed the growth of HCC cells in vitro and in vivo by inducing cell apoptosis.

Evaluation of the effectiveness of an ointment based on Alkannins/Shikonins on second intention wound healing in the dog

The enantiomeric naphthoquinones alkannins and shikonins (A/S) have been established as potent wound healing agents. The purpose of this study was to evaluate the effectiveness of an A/S based ointment for humans on second intention wound healing in the dog, as compared to wound flushing with Lactated Ringer's solution (LRS). Ten mixed breed dogs, aged 2 to 5 y, were used. One 2.5 × 2.5 cm full-thickness skin defect was created on the lateral aspect of each arm for subjective evaluation, laser-Doppler flowmetry (LDF), and planimetry. Additionally, 3 matching 2 × 2 cm wounds were created on opposite sides of the dorsal midline for histologic evaluation. Wounds were treated once daily with the A/S based ointment on the right side and by flushing with LRS on the left until healed (about 20 d). During the healing process, tissue perfusion (mean LDF value) was found to be significantly higher on the side treated with the A/S based ointment compared with the LRS-treated side. Histologically, angiogenesis (on days 4 and 11), collagen production score (on days 4, 11, and 20), and epithelial thickness score (on day 11) were significantly higher in the wounds treated with the A/S based ointment. Wound size, as evaluated by planimetry, decreased significantly from day 0 to day 20 on both sides, but no significant differences were found between the A/S based ointment and LRS-treated wounds.

Examination of the impact of a range of Pluronic surfactants on the in-vitro solubilisation behaviour and oral bioavailability of lipidic formulations of atovaquone

Exogenous surfactants are increasingly used to enhance the dispersion properties of lipid-based formulations of poorly water-soluble drugs, yet their possible effects on formulation digestion and oral bioavailability in-vivo are not well documented. In this study, in-vitro dispersion and digestion experiments were conducted using formulations comprising a blend of long-chain glycerides, ethanol, a model poorly water-soluble drug (atovaquone), and a series of surfactants including Cremophor EL and a range of Pluronic surfactants (Pluronics L121, L61, L72, L43 and F68). Inclusion of Cremophor EL, a surfactant with a high hydrophilic-lipophilic balance (HLB), promoted complete digestion of the formulation and effective dispersion and solubilisation of the lipolytic products and co-administered drug. Surprisingly, formulations containing the Pluronic (L121) with the lowest HLB (0.5) equally effectively promoted digestion and drug solubilisation and a trend towards decreased digestion and drug solubilisation was observed with Pluronics of increasing HLB values. All formulations effectively prevented drug precipitation, suggesting possible utility in-vivo, and no correlation was evident between the ability of the formulations to self-emulsify on dispersion and to promote drug solubilisation on digestion. Subsequent assessment of the oral bioavailability of atovaquone after administration of formulations containing Cremophor EL or Pluronic L121 or a simple solution of atovaquone in long-chain glycerides confirmed the utility of lipid-based formulations for enhancing the oral bioavailability of poorly water-soluble drugs such as atovaquone, but also indicated that in some cases microemulsion preconcentrate formulations may not provide additional bioavail-ability benefits beyond that achievable using simple lipid solutions.

Novel role of Pin1 induction in type II collagen-mediated rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation in joints and subsequent destruction of cartilage and bone. Inflammatory mediators such as PGs and proinflammatory cytokines contribute to RA progress. Pin1, a peptidyl prolyl isomerase, plays important pathophysiological roles in several diseases, including cancer and neurodegeneration. We found that both Pin1 and cyclooxygenase-2 (COX-2) were highly expressed in ankle tissues of type II collagen-induced RA mice. HTB-94 cells overexpressing Pin1 and primary cultured human chondrocytes showed increased basal expression of proinflammatory proteins (COX-2, inducible NO synthase, TNF-alpha, and IL-1beta). Site-directed mutagenesis revealed that Pin1-mediated transcriptional activation of COX-2 was coordinately regulated by NF-kappaB, CREB, and C/EBP. Gel shift, reporter gene, and Western blot analyses confirmed that NF-kappaB, CREB, and C/EBP were consistently activated in chondrocytes overexpressing Pin1. Treatment of RA mice with juglone, a chemical inhibitor of Pin1, significantly reduced RA progress and COX-2 expression in the ankle tissues. Moreover, juglone dose dependently decreased the basal COX-2 expression in primary cultured chondrocytes from RA patients. These results demonstrate that Pin1 induction during RA progress stimulates proinflammatory protein expression by activating NF-kappaB, CREB, and C/EBP, and suggest that Pin1 is a potential therapeutic target of RA.

Synthesis and insect antifeedant activity of plumbagin derivatives with the amino acid moiety

A series of plumbagin derivatives (4a-4k) containing an amino acid moiety were synthesized under mild esterification conditions in excellent yields (35%-80%) and screened for their antifeedant activities in tobacco caterpillar (Spodoptera litura) and castor semilooper (Achaea janata) using a no-choice laboratory bioassay. The parent compound plumbagin lacked significant activity, but the analogues were effective in reducing feeding by two insect species. The introduction of an N-acetyl-l-amino acid side chain to the Michael adduct of plumbagin at the third position of the quinone moiety significantly increased antifeedant activity. Several of the analogues were also toxic or caused developmental abnormalities following topical administration.