Ex vivo drug sensitivity screening predicts response to temozolomide in glioblastoma patients and identifies candidate biomarkers.

BACKGROUND: Patient-derived glioma stem-like cells (GSCs) have become the gold-standard in neuro-oncological research; however, it remains to be established whether loss of in situ microenvironment affects the clinically-predictive value of this model. We implemented a GSC monolayer system to investigate in situ-in vitro molecular correspondence and the relationship between in vitro and patient response to temozolomide (TMZ). METHODS: DNA/RNA-sequencing was performed on 56 glioblastoma tissues and 19 derived GSC cultures. Sensitivity to TMZ was screened across 66 GSC cultures. Viability readouts were related to clinical parameters of corresponding patients and whole-transcriptome data. RESULTS: Tumour DNA and RNA sequences revealed strong similarity to corresponding GSCs despite loss of neuronal and immune interactions. In vitro TMZ screening yielded three response categories which significantly correlated with patient survival, therewith providing more specific prediction than the binary MGMT marker. Transcriptome analysis identified 121 genes related to TMZ sensitivity of which 21were validated in external datasets. CONCLUSION: GSCs retain patient-unique hallmark gene expressions despite loss of their natural environment. Drug screening using GSCs predicted patient response to TMZ more specifically than MGMT status, while transcriptome analysis identified potential biomarkers for this response. GSC drug screening therefore provides a tool to improve drug development and precision medicine for glioblastoma.

Disruption of Glioblastoma Multiforme Cell Circuits with Cinnamaldehyde Highlights Potential Targets with Implications for Novel Therapeutic Strategies.

Glioblastoma multiforme (GBM) is a major aggressive primary brain tumor with dismal survival outcome and few therapeutic options. Although Temozolomide (TMZ) is a part of the standard therapy, over time, it can cause DNA damage leading to deleterious effects, necessitating the discovery of drugs with minimal side effects. To this end, we investigated the effect of cinnamaldehyde (CA), a highly purified, single ingredient from cinnamon, on the GBM cell lines U87 and U251 and the neuroglioma cell line H4. On observing similar impact on the viability in all the three cell lines, detailed studies were conducted with CA and its isomer/analog, trans-CA (TCA), and methoxy-CA (MCA) on U87 cells. The compounds exhibited equal potency when assessed at the cellular level in inhibiting U87 cells as well as at the molecular level, resulting in an increase in reactive oxygen species (ROS) and an increase in the apoptotic and multicaspase cell populations. To further characterize the key entities, protein profiling was performed with CA. The studies revealed differential regulation of entities that could be key to glioblastoma cell circuits such as downregulation of pyruvate kinase-PKM2, the key enzyme of the glycolytic pathway that is central to the Warburg effect. This allows for monitoring the levels of PKM2 after therapy using recently developed noninvasive technology employing PET [18F] DASA-23. Additionally, the observation of downregulation of phosphomevalonate kinase is significant as the brain tumor initiating cells (BTIC) are maintained by the metabolism occurring via the mevalonate pathway. Results from the current study, if translated in vivo, could provide additional efficacious treatment options for glioblastoma with minimal side effects.

Morusinol extracted from Morus alba induces cell cycle arrest and apoptosis via inhibition of DNA damage response in melanoma by CHK1 degradation through the ubiquitin-proteasome pathway.

BACKGROUD: Flavonoids have a variety of biological activities, such as anti-inflammation, anti-tumor, anti-thrombosis and so on. Morusinol, as a novel isoprene flavonoid extracted from Morus alba root barks, has the effects of anti-arterial thrombosis and anti-inflammatory in previous studies. However, the anti-cancer mechanism of morusinol remains unclear. PURPOSE: In present study, we mainly studied the anti-tumor effect of morusinol and its mode of action in melanoma. METHODS: The anti-cancer effect of morusinol on melanoma were evaluated by using the MTT, EdU, plate clone formation and soft agar assay. Flow cytometry was used for detecting cell cycle and apoptosis. The É£-H2AX immunofluorescence and the alkaline comet assay were used to detect DNA damage and the Western blotting analysis was used to investigate the expressions of DNA-damage related proteins. Ubiquitination and turnover of CHK1 were also detected by using the immunoprecipitation assay. The cell line-derived xenograft (CDX) mouse models were used in vivo to evaluate the effect of morusinol on tumorigenicity. RESULTS: We demonstrated that morusinol not only had the ability to inhibit cell proliferation, but also induced cell cycle arrest at G0/G1 phase, caspase-dependent apoptosis and DNA damage in human melanoma cells. In addition, morusinol effectively inhibited the growth of melanoma xenografts in vivo. More strikingly, CHK1, which played an important role in maintaining the integrity of cell cycle, genomic stability and cell viability, was down-regulated in a dose- and time-dependent manner after morusinol treatment. Further research showed that CHK1 was degraded by the ubiquitin-proteasome pathway. Whereafter, morusinol-induced cell cycle arrest, apoptosis and DNA damage were partially salvaged by overexpressing CHK1 in melanoma cell lines. Herein, further experiments demonstrated that morusinol increased the sensitivity of dacarbazine (DTIC) to chemotherapy for melanoma in vitro and in vivo. CONCLUSION: Morusinol induces CHK1 degradation through the ubiquitin-proteasome pathway, thereby inducing cell cycle arrest, apoptosis and DNA damage response in melanoma. Our study firstly provided a theoretical basis for morusinol to be a candidate drug for clinical treatment of cancer, such as melanoma, alone or combinated with dacarbazine.

Carotenoids from Marine Microalgae as Antimelanoma Agents.

Melanoma cells are highly invasive and metastatic tumor cells and commonly express molecular alterations that contribute to multidrug resistance (e.g., BRAFV600E mutation). Conventional treatment is not effective in a long term, requiring an exhaustive search for new alternatives. Recently, carotenoids from microalgae have been investigated as adjuvant in antimelanoma therapy due to their safety and acceptable clinical tolerability. Many of them are currently used as food supplements. In this review, we have compiled several studies that show microalgal carotenoids inhibit cell proliferation, cell migration and invasion, as well as induced cell cycle arrest and apoptosis in various melanoma cell lines. MAPK and NF-ĸB pathway, MMP and apoptotic factors are frequently affected after exposure to microalgal carotenoids. Fucoxanthin, astaxanthin and zeaxanthin are the main carotenoids investigated, in both in vitro and in vivo experimental models. Preclinical data indicate these compounds exhibit direct antimelanoma effect but are also capable of restoring melanoma cells sensitivity to conventional chemotherapy (e.g., vemurafenib and dacarbazine).

Combined Therapy with Dacarbazine and Hyperthermia Induces Cytotoxicity in A375 and MNT-1 Melanoma Cells.

Melanoma is a drug-resistant cancer, representing a serious challenge in cancer treatment. Dacarbazine (DTIC) is the standard drug in metastatic melanoma treatment, despite the poor results. Hyperthermia has been proven to potentiate chemotherapy. Hence, this work analyzed the combined action of hyperthermia and DTIC on A375 and MNT-1 cell lines. First, temperatures between 40 °C and 45 °C were tested. The effect of DTIC on cell viability was also investigated after exposures of 24, 48, and 72 h. Then, cells were exposed to 43 °C and to the respective DTIC IC10 or IC20 of each time exposure. Overall, hyperthermia reduced cell viability, however, 45 °C caused an excessive cell death (>90%). Combinational treatment revealed that hyperthermia potentiates DTIC's effect, but it is dependent on the concentration and temperature used. Also, it has different mechanisms from the treatments alone, delaying A375 cells at the G2/M phase and MNT-1 cells at the S and G2/M phases. Intracellular reactive oxygen species (ROS) levels increased after treatment with hyperthermia, but the combined treatment showed no additional differences. Also, hyperthermia highly increased the number of A375 early apoptotic cells. These results suggest that combining hyperthermia and DTIC should be more explored to improve melanoma treatment.

Codonopsis pilosula polysaccharide in synergy with dacarbazine inhibits mouse melanoma by repolarizing M2-like tumor-associated macrophages into M1-like tumor-associated macrophages.

BACKGROUND: The incidence and associated mortality of melanoma have increased significantly in recent years but treatment options are plagued with many undesirable side effects. Traditional Chinese herbal medicine polysaccharides are gaining increasing attention due to their potential role in the treatment of chronic diseases including tumors and the regulation of the immune system. METHODS: In this study, the potential effects of Ganoderma lucidum crude polysaccharides (GLCP) and Codonopsis pilosula crude polysaccharides (CPCP) on melanoma in C57 mice were explored. In addition, the inhibition and repolarization effect of digested Codonopsis pilosula polysaccharide (dCPP) on the proliferation of tumor-associated macrophages (TAMs) with M2-like phenotype induced by IL-4 were investigated. RESULTS: The results showed that the various polysaccharides could significantly reduce tumor volume in melanoma mice. GLCP and GLCP + CPCP could further significantly reduce the number of CD68+ macrophages in tumors and also prolong survival in melanoma mice to a certain extent. Significantly, dCPP could inhibit the proliferation of IL-4-induced M2-like TAMs, and significantly increase the mRNA expression levels of IL-1, IL-6, iNOS and TNF-a, thereby promoting the repolarization of M2-like TAMs to M1-like TAMs. CONCLUSION: Overall, it could be deduced that GLCP, CPCP and dCPP hold great potential as safe therapeutic options for melanoma and an immune-modulator which may require further exploration.

Bixin, an apocarotenoid isolated from Bixa orellana L., sensitizes human melanoma cells to dacarbazine-induced apoptosis through ROS-mediated cytotoxicity.

Cutaneous melanoma has a high capacity to metastasize and significant resistance to conventional therapeutic protocols, which makes its treatment difficult. The combination of conventional drugs with cytostatic molecules of low toxicity has been shown to be an interesting alternative for sensitization of tumor cells to chemotherapy. In this study, we evaluated the effect of bixin, an abundant apocarotenoid present in Bixa orellana, on the sensitization of human melanoma cells (A2058) to dacarbazine treatment, an anticancer agent clinically used for the therapy of metastatic melanoma. UPLC-DAD-MS/MS analyses of bioactive extracts from B. orellana seeds led to the identification of two new apocarotenoids: 6,8'-diapocarotene-6,8'-dioic acid and 6,7'-diapocarotene-6,7'-dioic acid. After being identified as its major compound, bixin (Z-bixin) was evaluated on A2058 cells expressing the oncogenic BRAF VE600 mutation and resistant to dacarbazine treatment. Bixin promoted growth inhibition, reduced cell migration, induced apoptosis and cell cycle arrest in the G2/M phase. When associated with dacarbazine, bixin restored the sensitivity of A2058 cells to chemotherapy, enhancing its antiproliferative, anti-migratory and pro-apoptotic effects. Combined treatment also induced higher ROS (reactive oxygen species) and MDA (malondialdehyde, a lipid peroxidation marker) generation than monotreatment, suggesting that the oxidative stress caused by bixin contributes significantly to its sensitizing effect. Taken together, these data suggest that bixin exerts intrinsic antimelanoma activity by mechanisms complementary to those of dacarbazine, encouraging its use in combined therapy for cutaneous melanoma treatment.

Drug resistance in glioblastoma and cytotoxicity of seaweed compounds, alone and in combination with anticancer drugs: A mini review.

BACKGROUND: Glioblastomas (GBM) are one of the most aggressive tumor of the central nervous system with an average life expectancy of only 1-2 years after diagnosis, even with the use of advanced treatments with surgery, radiation, and chemotherapy. There are several anticancer drugs with alkylating properties that have been used in the therapy of malignant gliomas. Temozolomide (TMZ) is one of them, widely used even in combination with ionizing radiation. However, the main disadvantage of using these types of drugs in the treatment of GBM is the development of cancer drug resistance. Research of bioactive compounds with anticancer activity has been heavily explored. PURPOSE: This review focuses on a carotenoid and a phlorotannin present in seaweed, namely fucoxanthin and phloroglucinol, and their anticancer activity against glioblastoma. The combination of natural compounds with conventional drugs is also discussed. CONCLUSION: Several natural compounds existing in seaweeds, such as fucoxanthin and phoroglucinol, have shown cytotoxic activity in models in vitro and in vivo, acting through different molecular mechanisms, such as antioxidant, antiproliferative, DNA damage/DNA repair, proapoptotic, antiangiogenic and antimetastic. Within the scope of interactions with conventional drugs, there are evidences that some seaweed compounds could be used to potentiate the action of anticancer drugs. However, their effects and mechanisms of action, alone or in combination with anticancer drugs, namely TMZ, in glioblastoma cell, still few explored and require more attention due to the unquestionable high potential of these marine compounds.

Honokiol enhances temozolomide-induced apoptotic insults to malignant glioma cells via an intrinsic mitochondrion-dependent pathway.

BACKGROUND: Temozolomide (TMZ) is a first-line chemotherapeutic drug for malignant gliomas. Nonetheless, TMZ-induced side effects and drug resistance remain challenges. Our previous study showed the suppressive effects of honokiol on growth of gliomas. PURPOSE: This study was further aimed to evaluate if honokiol could enhance TMZ-induced insults toward malignant glioma cells and its possible mechanisms. METHODS: Human U87 MG glioma cells were exposed to TMZ, honokiol, and a combination of TMZ and honokiol. Cell survival, apoptosis, necrosis, and proliferation were successively assayed. Fluorometric substrate assays were conducted to determine activities of caspase-3, -6, -8, and -9. Levels of Fas ligand, Bax, and cytochrome c were immunodetected. Translocation of Bax to mitochondria were examined using confocal microscopy. Mitochondrial function was evaluated by assaying the mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and complex I enzyme activity. Caspase-6 activity was suppressed using specific peptide inhibitors. The honokiol-induced effects were further confirmed using human U373 MG and murine GL261 cells. RESULTS: Exposure of human U87 MG glioma cells to honokiol significantly increased TMZ-induced DNA fragmentation and cell apoptosis. Interestingly, honokiol enhanced intrinsic caspase-9 activity without affecting extrinsic Fas ligand levels and caspase-8 activity. Sequentially, TMZ-induced changes in Bax translocation, the MMP, mitochondrial complex I enzyme activity, intracellular ROS levels, and cytochrome c release were enhanced by honokiol. Consequently, honokiol amplified TMZ-induced activation of caspases-3 and -6 in human U87 MG cells. Fascinatingly, suppressing caspase-6 activity concurrently decreased honokiol-induced DNA fragmentation and cell apoptosis. The honokiol-involved improvement in TMZ-induced intrinsic apoptosis was also confirmed in human U373 MG and murine GL261 glioma cells. CONCLUSIONS: This study showed that honokiol can enhance TMZ-induced apoptotic insults to glioma cells via an intrinsic mitochondrion-dependent mechanism. Our results suggest the therapeutic potential of honokiol to attenuate TMZ-induced side effects.

Juniperus Communis Extract Exerts Antitumor Effects in Human Glioblastomas Through Blood-Brain Barrier.

BACKGROUND/AIMS: Herbal materials derived from Juniperus communis (JCo) possess anticancer activity. In this study, we evaluated the efficacy of a JCo berry extract in suppressing glioblastoma growth. METHODS: The effects of JCo extract on the viability of normal and glioma cell lines was analyzed using a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The synergistic therapeutic effect of JCo extract and temozolomide (TMZ) on glioma cells was examined by MTT analysis. Flow cytometry analysis, the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) test, and western blotting were performed to identify the apoptotic pathway. To determine the in vivo efficacy of the JCo extract, rats were injected with 5 × 104 rat glioma RG2 cells in the back skin and brain hemisphere and then received a subcutaneous injection in the back skin that contained either JCo extract or vehicle. Finally, blood and histologic examinations were performed to evaluate JCo toxicity. RESULTS: The IC50 values of JCo extract were 57-69 µg/mL and 49-67 µg/mL in the glioblastoma cell lines after 24 and 48 h, respectively. However, in non-tumor cell lines, the respective IC50 values of JCo extract were 76-105 µg/mL and 77-108 µg/mL. The JCo extract had a stronger cytotoxicity and a larger range of IC50 values in glioma than in normal cells as compared to those effects caused by temozolomide (TMZ). In addition, the results of flow cytometry analysis, TUNEL test, and western blotting revealed that the JCo extract induced glioma cell cycle arrest through intrinsic and extrinsic apoptotic pathways. In the in vivo studies, a significant reduction of tumor size in JCo-treated rats, as measured by animal MRI, demonstrated that the JCo extract effectively inhibited glioma cell growth and successfully penetrated the blood-brain barrier. The immunohistochemical (IHC) staining detected positive signals of PCNA, VEGFR-1, and VEGFR -2 in 44.49%, 5.88%, and 5.85% of JCo-treated glioma cells, respectively. However, positive signals of PCNA, VEGFR-1, and VEGFR-2 were detected in 73.08%, 9.67%, and 11.70% of vehicle-treated glioma cells, respectively. The IHC examination of PCNA and VEGFR-1 and -2 indicated that JCo extract significantly decreased the degree of neovascularization. However, no significant differences in serum levels of blood cell count and hepatic enzymes, renal function index, and the histologic appearance of vital organs were detected between the JCo and vehicle-treated rats. CONCLUSION: The JCo extract penetrated the blood-brain barrier and significantly induced glioma cell apoptosis by reducing neovascularization via suppression of the PI3K/AKT/mTOR pathway. Furthermore, JCo extract was less cytotoxic to non-neoplastic vital organs than TMZ.

Alternating Electric Fields Therapy for Malignant Gliomas: From Bench Observation to Clinical Reality.

Alternating electric fields of intermediate frequencies, also known as Tumor Treating Fields (TTFields or TTF) is a novel anticancer treatment modality that disrupts tumor cell mitosis at the metaphase-anaphase transition, leading to mitotic catastrophe, aberrant mitotic exit, and/or cell death. It is realized through alteration of the cytokinetic cleavage furrow by interference of proteins possessing large dipole moments, like septin heterotrimer complex and α/ß-tubulin, and that results in disordered membrane contraction and failed cytokinesis. Aberrant mitotic exit also elicits immunogenic cell death, which may potentiate an immune response against treated tumors. Notably, in patients with recurrent glioblastoma multiforme (GBM) a prospective clinical trial demonstrated comparable overall survival and progression-free survival after TTFields therapy and best physician's choice chemotherapy. Moreover, it was shown that in patients with newly diagnosed GBM initially treated with standard chemoradiotherapy with daily temozolomide (TMZ), adjuvant TTFields combined with TMZ offered better survival than adjuvant TMZ alone. Therefore, TTFields therapy can be appreciated as a standard treatment option in cases of intracranial malignant gliomas, whereas future studies should establish its optimal combination with other existing anticancer modalities, which may offer additional survival benefits for patients.

Targeting LMW-PTP to sensitize melanoma cancer cells toward chemo- and radiotherapy.

Tumor resistance to apoptosis is one the main causes of anticancer treatment failure. Previous studies showed that LMW-PTP overexpression enhances resistance of cancer cells to traditional anticancer drugs. Today, the role of LMW-PTP in inducing resistance to apoptosis in melanoma cells remains to be elucidated. Experimental setting include MTT assay, Annexin V/Pi method, and colony assay to assess whether silencing of LMW-PTP improves the sensitivity of A375 to dacarbazine, 5-FU, and radiotherapy. Pharmacological targeting of LMW-PTP was obtained using Morin, a LMW-PTP inhibitor. The ability of Morin to improve the effectiveness of anticancer drugs and radiotherapy was also studied. Moreover, PC3 cells were used as an alternative cellular model to confirm the data obtained with melanoma cells. We found that LMW-PTP silencing improves the effectiveness of dacarbazine, 5-FU, and radiotherapy. Identical results were obtained in vivo when Morin was used to target LMW-PTP. We demonstrated that Morin synergizes with dacarbazine, improving its cytotoxic activity. However, we showed that the combined treatment, Morin-anticancer drug, does not affect the viability of noncancerous cells. Knockdown of LMW-PTP sensitizes also PC3 cells to docetaxel and radiotherapy. In conclusion, we showed that LMW-PTP targeting improves effectiveness of anticancer drugs used for treatment of melanoma. Moreover, our results suggest that Morin could be used as adjuvant to improve the outcome of patients affected by metastatic melanoma.

Opposite Interplay Between the Canonical WNT/ß-Catenin Pathway and PPAR Gamma: A Potential Therapeutic Target in Gliomas.

In gliomas, the canonical Wingless/Int (WNT)/ß-catenin pathway is increased while peroxisome proliferator-activated receptor gamma (PPAR-γ) is downregulated. The two systems act in an opposite manner. This review focuses on the interplay between WNT/ß-catenin signaling and PPAR-γ and their metabolic implications as potential therapeutic target in gliomas. Activation of the WNT/ß-catenin pathway stimulates the transcription of genes involved in proliferation, invasion, nucleotide synthesis, tumor growth, and angiogenesis. Activation of PPAR-γ agonists inhibits various signaling pathways such as the JAK/STAT, WNT/ß-catenin, and PI3K/Akt pathways, which reduces tumor growth, cell proliferation, cell invasiveness, and angiogenesis. Nonsteroidal anti-inflammatory drugs, curcumin, antipsychotic drugs, adiponectin, and sulforaphane downregulate the WNT/ß-catenin pathway through the upregulation of PPAR-γ and thus appear to provide an interesting therapeutic approach for gliomas. Temozolomide (TMZ) is an antiangiogenic agent. The downstream action of this opposite interplay may explain the TMZ-resistance often reported in gliomas.

Hyperthermia with different temperatures inhibits proliferation and promotes apoptosis through the EGFR/STAT3 pathway in C6 rat glioma cells.

Malignant gliomas are a group of aggressive neoplasms among human cancers. The curative effects of current treatments are finite for improving the prognosis of patients. Hyperthermia (HT) is an effective treatment for cancers; however, the effects of HT with different temperatures in treatment of MG and relevant mechanisms remain unclear. MTT assay and Annexin V­fluorescein isothiocyanate/propidium iodide staining were used for investigating the proliferation and apoptosis of C6 cells, respectively. Western blotting was applied to detect the expression of proteins. Ultrasonography was employed to evaluate the tumor formation rate, growth rate, angiogenesis rate and degree of hardness of tumors in vivo. The authors certified that HT with 42­46˚C x 1 h, 1 t could inhibit proliferation, promote apoptosis, reduce tumor formation rate, growth rate, angiogenesis rate, degree of hardness of tumors, ischemic tolerance and anoxic tolerance, and have synergy with temozolomide in C6 cells. Long­term HT (43˚C x 1 h, 1 t/5 d, 90 d) did not cut down the sensitivity of C6 cells to HT, and sustainably inhibited the proliferation of C6 cells. Furthermore, the authors proved HT produced these effects primarily through inhibition of the EGFR/STAT3/HIF­1A/VEGF­A pathway.

Probing the Oncolytic and Chemosensitizing Effects of Dihydrotanshinone in an In Vitro Glioblastoma Model.

BACKGROUND: Temozolomide is the primary chemotherapeutic agent used to treat glioblastoma. However, many tumors are initially resistant to or develop resistance to temozolomide, mainly due to high levels of O6-methylguanine DNA transferase (MGMT) which repairs DNA damage traditionally caused by temozolomide. Dihydrotanshinone (DHT) is extracted from Salvia miltiorrhiza, a Chinese medicinal plant, and has also been shown to have antiproliferative effects on various cancer cell lines. DHT has been to shown to induce apoptosis via induction endoplasmic reticulum stress, that can reportedly sensitize cells to temozolomide. MATERIALS AND METHODS: MTS cellular proliferation assays or trypan blue viability assays were used to determine the effects of DHT/temozolomide combinatorial treatment. Enzyme-linked immunosorbent assay (ELISA) was used to determine effects on MGMT and P-glycoprotein levels after singular and combinatorial treatment. RESULTS: DHT had a synergistic oncolytic effect in a MGMT-deficient cell line and a sensitizing effect in a MGMT-expressing cell line. Cytotoxicity due to DHT was shown to be reactive oxygen species-dependent, while the combinatorial effect of DHT and temozolomide synergistically reduced MGMT and P-glycoprotein levels. CONCLUSION: DHT was shown to augment temozolomide efficacy, indicating that, since DHT can penetrate the blood-brain barrier, temozolomide in combination with DHT may represent a promising therapeutic option for glioblastoma.

Radicol, a Novel Trinorguaiane-Type Sesquiterpene, Induces Temozolomide-Resistant Glioma Cell Apoptosis via ER Stress and Akt/mTOR Pathway Blockade.

Glioblastoma multiforme (GBM) is the most frequent, lethal and aggressive tumour of the central nervous system (CNS) in adults. Multidrug resistance (MDR) results in undesirable prognosis during GBM chemotherapy. In this study, we determined that Radicol (RAD), a novel trinorguaiane-type sesquiterpene originally isolated from the root of Dictamnus radicis Cortex, exhibited potently cytotoxic effect on temozolomide (TMZ)-resistant GBM cell lines in a dose-dependent manner. Radicol-induced apoptosis was confirmed with Hoechst 33342/propidium iodide and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end-labelling (TUNEL) staining. Studies investigating the mechanism revealed that RAD triggered an attenuation of protein disulphide isomerase (PDI) and induced the unmitigated unfolded protein response (UPR) and lethal endoplasmic reticulum (ER) stress. Simultaneously, we further demonstrated that RAD suppressed the activation of Akt/mTOR/p70S6K phosphorylation by up-regulating the induction of glycogen synthase kinase-3ß (GSK-3ß). These results established a link between RAD-induced ER stress and inhibition of the Akt/mTOR/p70S6K pathway, and the attenuation of PDI and activation of GSK-3ß might be the synergistic target of antineoplastic effects during RAD-induced apoptosis. These findings suggested that RAD, possessing multiple cytotoxicity targets, low molecular weight and high lipid solubility, could be a promising agent for the treatment of malignant gliomas. Copyright © 2017 John Wiley & Sons, Ltd.

Ghee Butter as a Therapeutic Delivery System.

Solid lipid nanoparticles carrying a chemotherapeutic payload (i.e., temozolomide, TMZ) were synthesized using ghee, a clarified butter commonly used in traditional medicine and food products. Ghee solid lipid nanoparticles (GSLN) were characterized through dynamic light scattering, scanning electron microscopy, and UV-visible spectrometry. Formulations were generated with varying ratios of surfactant to lipid, resulting in a maximum TMZ entrapment efficiency of ˜70%. Optimal formulations were found to have an average size and polydispersity of ˜220 nm and 0.340, respectively. Release kinetics revealed TMZ-loaded GSLN (TMZ@GSLN) retained 10% of its pay-load at 2 h with ˜53% released in 5 h. Metabolic activity on human umbilical vein endothelial cells (HUVEC) revealed GSLN treatment resulted in an increase in viability following 3 d while treatment of glioblastoma LN-229 cells with TMZ@GSLN resulted in a significant decrease. Evaluation of diffusion of TMZ across a reconstructed HUVEC monolayer demonstrated TMZ@GSLN resulted in a significantly higher diffusion of drug when compared to free TMZ. This data suggests GSLN pose a promising delivery vehicle for TMZ-based therapeutics. Collectively, this data demonstrates GSLN exhibit favorable drug carrier properties with anti-proliferative properties in glioblastoma cancer cells.

Synergistic anti-glioma effect of a coloaded nano-drug delivery system.

The anti-glioma effect of temozolomide (Tem) is sometimes undermined by the emerging resistance. Recently, resveratrol (Res), herbal medicine extracted from grape seeds, has been demonstrated for its potential use in chemosensitization. In the current study, both these drugs were loaded simultaneously into nanoparticles with methoxy poly(ethylene glycol)-poly epsilon caprolactone (mPEG-PCL) as drug carriers in order to achieve better antitumor efficiency. Tem/Res-coloaded mPEG-PCL nanoparticles were constructed, characterized, and tested for antitumor effect on glioma cells by using in vitro and xenograft model system. The nanoparticle constructs were satisfactory with drug loading content (Res =~12.4%; Tem =~9.3%) and encapsulation capacity of >85% for both the drugs. In addition, the coencapsulation led to better in vitro stability of the nanoparticles than Tem-loaded nanoparticles. An in vitro uptake study demonstrated a high uptake efficiency of the nanoparticles by glioma cells. The synergistic antitumor effect against glioma cells was observed in the combinational treatment of Res and Tem. Tem/Res-coloaded nanoparticles induced higher apoptosis in U87 glioma cells as compared to cells treated by the combination of free drugs. Tem/Res-coloaded particles caused more effective inhibition of phosphor-Akt, leading to upregulation of the downstream apoptotic proteins. In addition, the in vivo study showed the superior tumor delaying effect of coloaded nanoparticles than that of free drug combination. These results suggest that Tem/Res-coloaded nanoparticles could be a potential useful chemotherapeutic formulation for glioma therapy.

Evaluating the cytotoxic effects of the water extracts of four anticancer herbs against human malignant melanoma cells.

Malignant melanoma (MM) is the most dangerous type of skin cancer, killing more than 1,100 people each year in Canada. Prognosis for late stage and recurrent MM is extremely poor due to insensitivity to chemotherapy drugs, and thus many patients seek complementary and alternative medicines. In this study, we examined four commonly used anticancer herbs in traditional Chinese medicine, Hedyotis diffusa, Scutellaria barbata, Lobelia chinensis, and Solanum nigrum, for their in vitro antitumor effects toward human MM cell line A-375. The crude water extract of S. nigrum (1 g of dry herb in 100 mL water) and its 2-fold dilution caused 52.8%±13.0% and 17.3%±2.7% cytotoxicity in A-375 cells, respectively (P<0.01). The crude water extract of H. diffusa caused 11.1%±12.4% cytotoxicity in A-375 cells with no statistical significance (P>0.05). Higher concentrated formulation might be needed for H. diffusa to exert its cytotoxic effect against A-375 cells. No cytotoxicity was observed in A-375 cells treated with crude water extract of S. barbata and L. chinensis. Further high performance liquid chromatography-tandem mass spectroscopy analysis of the herbal extracts implicated that S. nigrum and H. diffusa might have adopted the same bioactive components for their cytotoxic effects in spite of belonging to two different plant families. We also showed that the crude water extract of S. nigrum reduced intracellular reactive oxygen species generation in A-375 cells, which may lead to a cytostatic effect. Furthermore, synergistic effect was achieved when crude water extract of S. nigrum was coadministered with temozolomide, a chemotherapy drug for skin cancer.

Chemical Screening Identifies EUrd as a Novel Inhibitor Against Temozolomide-Resistant Glioblastoma-Initiating Cells.

Glioblastoma (GBM), one of the most malignant human cancers, frequently recurs despite multimodal treatment with surgery and chemo/radiotherapies. GBM-initiating cells (GICs) are the likely cell-of-origin in recurrences, as they proliferate indefinitely, form tumors in vivo, and are resistant to chemo/radiotherapies. It is therefore crucial to find chemicals that specifically kill GICs. We established temozolomide (the standard medicine for GBM)-resistant GICs (GICRs) and used the cells for chemical screening. Here, we identified 1-(3-C-ethynyl-ß-d-ribopentofuranosyl) uracil (EUrd) as a selective drug for targeting GICRs. EUrd induced the death in GICRs more effectively than their parental GICs, while it was less toxic to normal neural stem cells. We demonstrate that the cytotoxic effect of EUrd on GICRs partly depended on the increased expression of uridine-cytidine kinase-like 1 (UCKL1) and the decreased one of 5'-nucleotidase cytosolic III (NT5C3), which regulate uridine-monophosphate synthesis positively and negatively respectively. Together, these findings suggest that EUrd can be used as a new therapeutic drug for GBM with the expression of surrogate markers UCKL1 and NT5C3. Stem Cells 2016;34:2016-2025.