A chloroform extract of the edible mushroom Pleurotus eryngii showed an inhibitory effect on mammalian DNA topoisomerase I. The topoisomerase I inhibitory compound was purified and identified as ubiquinone-9. Ubiquinone-9 was shown to inhibit the activity of topoisomerase I with IC(50) of about 50 microM. Concentration of 110 microM ubiquinone-9 caused 50% growth inhibition of human leukaemia U937 cells, but not that of normal fibroblast NIH3T3 and 3Y1 cells. Ubiquinone-9-induced cell death was characterised with the cleavage of poly (ADP-ribose) polymerase and pro-caspase 3. Furthermore, ubiquinone-9 induced the fragmentation of DNA into an apoptotic DNA ladder, indicating that the inhibitor triggered apoptosis. The induction of apoptosis by ubiquinone-9 was also confirmed using flow cytometry analysis. Taken together, these results suggest that ubiquinone-9 may function by inhibiting oncogenic disease, at least in part, through the inhibition of topoisomerase I activity.

Hepatocellular carcinoma is a cancer of high mortality; therefore, the effective therapy on this cancer is an imperative issue. Recently, anticancer agent combined with natural products has been demonstrated to increase apoptosis of various cancer cells effectively. Accordingly, we investigated the apoptotic effect and possible mechanism of the ethanol extract from Taiwanofungus salmoneus (=Antrodia salmonea) mycelium (TsE) alone or in combination with cisplatin in SK-Hep-1 cells. In this study, the proliferation of SK-Hep-1 cells could be inhibited at various concentrations of TsE for 24 h whereas TsE combined with cisplatin would inhibit the cell proliferation more notably. Moreover, the DNA damage and the interruption of cell cycle of SK-Hep-1 cells would be effectively raised after incubation with TsE combined with cisplatin for 24 h. The apoptosis of cells was dramatically induced, and the expression of caspases 3, 8, and 9, apoptosis-related protein, were significantly upregulated. Therefore, we proposed that the TsE combined with cisplatin inhibited cell proliferation by elevating sub-G1 phase, inducing DNA damage, activating caspases 3, 8, and 9 activities, and triggering cells apoptosis. These results reveal that TsE could be a potential adjuvant chemotherapeutic agent.

Traditional therapies for pancreatic cancer are usually expensive and likely to cause side effects, and most patients have the risk of recurrence and suffering pain. Here, we investigated combination treatment of epigallocatechin-3-gallate (EGCG) and non-invasive low strength pulsed electric field (PEF) on the human pancreatic cell line PANC-1. Cells were cultured in various concentrations of EGCG and exposed to trains of PEF. The results showed that the low strength PEF alone or single treatment with low concentration of EGCG did not obviously affect the cell proliferation and migration in PANC-1. However, the EGCG-induced inhibitions of cell viability and migration ability in PANC-1 were dramatically enhanced by the further exposure of low strength PEF (60 V/cm). In particular, the same combination treatment caused less inhibition of cell viability in non-malignant HEK293 cells. We also found the combination treatment significantly decreased the ratio of Bcl-2/Bax protein and increased caspase activity in PANC-1 cells, resulting in the promotion of apoptotic responses, evidenced by chromatin condensation. The findings of the present study reveal the synergistic reactions in the combination treatment may severely disturb mitochondria, enhance the intrinsic pathway transduction, and effectively induce apoptosis; moreover, the migration and invasion of PANC-1 cancer cells were also significantly suppressed. Since normal cells are less sensitive to this combination treatment, and the non-invasive PEF could be modified to focus on a specific location, this treatment may serve as a promising method for anti-cancer therapy.

PURPOSE:While the benefits of ascorbic acid (vitamin C, ascorbate) as an essential nutrient are well established, its effects on tumor cells and in tumor treatment are controversial. In particular, conflicting data exist whether ascorbate may increase the cytotoxic effects of antineoplastic drugs or may rather exert adverse effects on drug sensitivity during cancer treatment. Findings are further obscured regarding the distinction between ascorbate and dehydroascorbate (DHA). Thus, the purpose of this study was to evaluate and directly compare the cytotoxic efficacy of ascorbate compared to DHA, and to analyse if ascorbate at pharmacological concentrations affects the efficacy of antineoplastic agents in prostate carcinoma cells.

METHODS:We directly compare the effects of ascorbate (supplied as 'Pascorbin solution for injection') and DHA on tumor cell viability, and determine IC(50) values for various cell lines. At concentrations well below the IC(50), ascorbate effects on cell proliferation and cell cycle are analysed. We furthermore determine changes in cellular sensitivity towards various cytostatic drugs upon pre-treatment of cells with ascorbate.

RESULTS:We demonstrate higher therapeutic efficacy of ascorbate over DHA in various cell lines, independent of cell line-specific differences in ascorbate sensitivity, and identify the extracellular generation of H(2)O(2) as critical mechanism of ascorbate action. We furthermore show that, in addition to pro-apoptotic effects described previously, ascorbate treatment already at concentrations well below the IC(50) exerts anti-proliferative effects on tumor cells. Those are based on interference with the cell cycle, namely by inducing a G(0)/G(1) arrest. Pre-treatment of tumor cells with ascorbate leads to increased cellular sensitivity towards Docetaxel, Epirubicin, Irinotecan and 5-FU, but not towards Oxaliplatin and Vinorelbin. For Docetaxel and 5-FU, a linear correlation between this sensitizing effect and the ascorbate dosage is observed.

CONCLUSIONS:The redox-active form of vitamin C, ascorbate, shows therapeutic efficacy in tumor cells. These antitumor effects of ascorbate are mainly based on its extracellular action and, in addition to the induction of apoptosis, also include an anti-proliferative effect by inducing cell cycle arrest. Furthermore, ascorbate treatment specifically enhances the cytostatic potency of certain chemotherapeutics, which implicates therapeutic benefit during tumor treatment.

Degradation of the extracellular matrix (ECM) plays a critical role in the formation of tumors and metastasis and has been found to correlate with the aggressiveness of tumor growth and invasiveness of cancer. Ascorbic acid, which is known to be essential for the structural integrity of the intercellular matrix, is not produced by humans and must be obtained from the diet. Cancer patients have been shown to have very low reserves of ascorbic acid. Our main objective was to determine the effect of ascorbate supplementation on metastasis, tumor growth and tumor immunohistochemistry in mice unable to synthesize ascorbic acid [gulonolactone oxidase (gulo) knockout (KO)] when challenged with B16FO melanoma or 4T1 breast cancer cells. Gulo KO female mice 36-38 weeks of age were deprived of or maintained on ascorbate in food and water for 4 weeks prior to and 2 weeks post intraperitoneal (IP) injection of 5x105 B16FO murine melanoma cells or to injection of 5x105 4T1 breast cancer cells into the mammary pad of mice. Ascorbate-supplemented gulo KO mice injected with B16FO melanoma cells demonstrated significant reduction (by 71%, p=0.005) in tumor metastasis compared to gulo KO mice on the control diet. The mean tumor weight in ascorbate supplemented mice injected with 4T1 cells was reduced by 28% compared to tumor weight in scorbuticmice. Scorbutic tumors demonstrated large dark cores, associated with increased necrotic areas and breaches to the tumor surface, apoptosis and matrix metalloproteinase-9 (MMP-9), and weak, disorganized or missing collagen I tumor capsule. In contrast, the ascorbate-supplemented group tumors had smaller fainter colored cores and confined areas of necrosis/apoptosis with no breaches from the core to the outside of the tumor and a robust collagen I tumor capsule. In both studies, ascorbate supplementation of gulo KO mice resulted in profoundly decreased serum inflammatory cytokine interleukin(IL)-6 (99% decrease, p=0.01 in the B16F0 study and 85% decrease, p=0.08 in the 4T1 study) compared to the levels in gulo KO mice deprived of ascorbate. In the B16FO study, ascorbate supplementation of gulo KO mice resulted in profoundly decreased serum VEGF (98% decrease, p=0.019 than in the scorbutic gulo KO mice). As expected, mean serum ascorbate level in ascorbate-restricted mice was 2% (p<0.001) of the mean ascorbate levels in supplemented mice. In conclusion, ascorbate supplementation hinders metastasis, tumor growth and inflammatory cytokine secretion as well as enhanced encapsulation of tumors elicited by melanoma and breast cancer cell challenge in gulo KO mice.

The present study hypothesized that the therapeutic use of ascorbic acid (AsA) in combination with radiation may reduce therapy-related side effects and increase the antitumor effects. The aim of the study was to examine the association between the scavenged activity of AsA and the biological anticancer effect of hydroxyl (OH) radicals generated by X-ray irradiation. Cell survival, DNA fragmentation of human leukemia HL60 cells and the amount of OH radicals were investigated following X-ray irradiation and AsA treatment. The number of living cells decreased, and DNA fragmentation increased at AsA concentrations>1 mM. Electron spin resonance spectra revealed that X-ray irradiation generated OH radicals, which were scavenged by AsA at concentrations>75µM. The AsA concentration inside the cell was 75 µM when cells underwent extracellular treatment with 5 mM AsA, which significantly induced HL60 cell death even without irradiation. No increase in the number of viable HL60 cells was observed following AsA treatment with irradiation when compared to irradiation alone. In conclusion, the disappearance of the radiation anticancer effects with AsA treatment in combination with radiotherapy for cancer treatment is not a cause for concern.

BACKGROUND:Adult T-cell leukemia (ATL) is an acute malignancy of activated T-cells caused by the human T-cell lymphotrophic virus type-1 (HTLV-1).

MATERIALS AND METHODS:The effects of non-cytotoxic concentrations of ascorbic acid (AA) were evaluated against HTLV-1 positive and negative cells. The effect of AA on apoptosis and proliferation was evaluated by cell cycle analysis. The role of p53, p21 Bax and Bcl-2a on cell cycle modulation and apoptosis was also assessed. The anti-proliferative effects were tested by determining the changes in the expression of transforming growth factors (TGF-alpha, TGF-beta1 and TGF-beta2).

RESULTS:Ascorbic acid was found to reduce the proliferation of cells and induce apoptosis by the modulation of p53, p21, Bcl-2 and Bax.

CONCLUSION:The results of this study show the anti-proliferative effects of AA against leukemic cells.

Ascorbic acid (AsA) is known as an antioxidant but concomitantly possesses a pro-oxidant property. Because the impact of AsA on photodynamic therapy response is unclear, we investigated the effect of AsA on photocytotoxicity induced by phloxine B in human acute promyelocytic leukemia HL-60 cells. AsA synergistically enhanced phloxine B-induced photocytotoxic effects, including inhibition of cell proliferation, DNA ladder formation, and caspase-3 activation, whereas AsA itself showed no photocytotoxicity. AsA also enhanced the consumption of the reduced glutathione level compared with the cells treated with phloxine B alone under the light condition. Combination of AsA with phloxine B under the light condition enhanced the phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (MAPK). These effects were completely cancelled by catalase. These results suggest that AsA synergistically enhances phloxine B-induced photocytotoxicity, possibly through the extracellular oxidative stress-dependent MAPK pathway activation.

Targeting autophagy may serve as a promising strategy for cancer therapy. Ganoderma lucidum polysaccharide (GLP) has been shown to exert promising anti-cancer effects. However, the underlying mechanisms remain elusive. Whether GLP regulates autophagy in cancer has never been reported. In this study, GLP induced the initiation of autophagy in colorectal cancer (CRC) HT-29 and HCT116 cells, as evidenced by enhanced level of LC3-II protein, GFP-LC3 puncta, and increased formation of double membrane vacuoles. However, GLP treatment caused marked increase of p62 expression. Addition of late stage autophagy inhibitor, chloroquine (CQ), further enhanced LC3-II and p62 level, as well as increased autophagosome accumulation, suggesting a blockage of autophagic flux by GLP in CRC cells. We then found GLP blocked autophagosome and lysosome fusion as determined by mRFP-GFP-LC3 colocalization analysis. Mechanistic study revealed that GLP-induced disruption of autophagosome-lysosome fusion is due to reduced lysosome acidification and lysosomal cathepsin activities. Cell viability and flow cytometry assays revealed that GLP-induced autophagosome accumulation is responsible for GLP-induced apoptosis in CRC cells. In line with this, inhibition of autophagy initiation by 3-methyladenine (3-MA), an early stage autophagy inhibitor, attenuated GLP-induced apoptosis. In contrast, suppression of autophagy at late stage by CQ enhanced the anti-cancer effect of GLP. Furthermore, we demonstrated that GLP-induced autophagosome accumulation and apoptosis is mediated via MAPK/ERK activation. Finally, GLP inhibited tumor growth and also inhibited autophagic flux in vivo. These results unveil new molecular mechanism underlying anti-cancer effects of GLP, suggesting that GLP is a potent autophagy inhibitor and might be useful in anticancer therapy.

ETHNOPHARMACOLOGICAL RELEVANCE:Inonotus obliquus, also known as Chaga mushroom, is one of the most widely appreciated wild edible mushrooms in Russia and northern European countries and is renowned for its use in cancer treatment. Indeed, recently published in vitro and in vivo studies have demonstrated its anticancer activity in various types of cancer and support its potential application for therapeutic intervention in cancer. However, its activity against lung cancer, the most commonly diagnosed cancer and the leading cause of cancer death worldwide, and the underlying molecular basis of its action remain to be fully elucidated.

OBJECTIVE:This study aimed to evaluate the cytotoxic activity of I. obliquus in four human lung adenocarcinoma cell lines with different p53 status (A549, H1264, H1299, and Calu-6) and identify its active constituents by bioactivity-based analysis and the underlying molecular basis of their cytotoxicity on lung cancer cells.

MATERIALS AND METHODS:Bioactivity-guided fractionation and preparative/semi-preparative HPLC purification were used with LC/MS analysis to separate the bioactive constituents. Cell viability and apoptosis in human lung cancer cell lines (A549, H1264, H1299, and Calu-6) were assessed using the WST-1 assay and TUNEL staining, respectively. Caspase activation was assessed by detecting its surrogate markers, cleaved poly (ADP-ribose) polymerase (PARP) and caspase-3, using an immunoblot assay.

RESULTS:The MeOH extract of I. obliquus reduced cell viability in all lung cancer cell lines tested through induction of apoptosis accompanied by caspase-3 cleavage. Bioactivity-guided fractionation of the MeOH extract and chemical investigation of its cytotoxic hexane-soluble and CHCl-soluble fractions led to the isolation of eight triterpenoids (1-8), including a new lanostane-type triterpenoid named chagabusone A (7). The structures of the isolates were elucidated based on spectroscopic analysis, including 1D and 2D NMR and high-resolution ESIMS. Among isolated compounds, compounds 1, 6, and 7 showed the most potent cytotoxic activity in all human lung cancer cell lines examined, with ICvalues ranging from 75.1 to 227.4 μM. Cytotoxicity of these compounds was mediated by apoptosis with caspase-3 activation.

CONCLUSION:These findings provide experimental evidence supporting the potential application of I. obliquus in lung cancer treatment and reveal the molecular basis underlying its cytotoxic activity against human lung cancer cells.

The present study was performed to examine the induction of apoptotic cell death and autophagy by blue LED irradiation, and the contribution of autophagy to apoptosis in B cell lymphoma A20 and RAMOS cells exposed to blue LED. Irradiation with blue LED reduced cell viability and induced apoptotic cell death, as indicated by exposure of phosphatidylserine on the plasma outside membrane and fragmentation of DNA. Furthermore, the mitochondrial membrane potential increased, and apoptotic proteins (PARP, caspase 3, Bax, and bcl-2) were observed. In addition, the level of intracellular superoxide anion (O2(-)) gradually increased. Interestingly the formation of autophagosomes and level of LC3-II were increased in blue LED-irradiated A20 and RAMOS cells, but inhibited after pretreatment with 3-methyladenine (3-MA), widely used as an autophagy inhibitor. Inhibition of the autophagic process by pretreatment with 3-MA blocked blue LED irradiation-induced caspase-3 activation. Moreover, a significant reduction of both the early and late phases of apoptosis after transfection with ATG5 and beclin 1 siRNAs was shown by the annexin V/PI staining, indicating a crucial role of autophagy in blue LED-induced apoptosis in cells. Additionally, the survival rate of mice irradiated with blue LED after injection with A20 cells increased compared to the control group. Our data demonstrate that blue LED irradiation induces apoptosis via the mitochondrial-mediated pathway, in conjunction with autophagy. Further studies are needed to elucidate the precise mechanism of blue LED-induced immune cell death.

Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm(2) (=0.52mW/cm(2) irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD50) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research.

BACKGROUND: Homeopathy is a complementary medicine widely used around the world. Despite extensive use of homeopathy for cancer and other serious conditions with reported success, clinical and laboratory research has been equivocal, and no rigorous research has been done on cancer. In 1999, the US National Cancer Institute evaluated the effects of homeopathic treatment of cancer from a clinic in India and has released a request for protocols to conduct further research into this treatment. Therefore, the authors conducted a series of carefully controlled laboratory studies evaluating the effects of commonly used homeopathic remedies in cell and animal models of prostate cancer. STUDY DESIGN: One hundred male Copenhagen rats were randomly assigned to either treatment or control groups after inoculation with prostate tumor cells. METHODS: Prostate tumor cells DU-145, LNCaP, and MAT-LyLu were exposed to 5 homeopathic remedies. Male Copenhagen rats were injected with MAT-LyLu cells and exposed to the same homeopathic remedies for 5 weeks. In vitro outcomes included tumor cell viability and apoptosis gene expression. In vivo outcomes included tumor incidence, volume, weight, total mortality, proliferating cell nuclear antigen (PCNA) expression, apoptotic cell death (terminal deoxynucleotidyl transferase mediated d-uridine triphosphate nick end labeling), and gene expression (rAPO-multiprobe). RESULTS: There were no effects on cell viability or gene expression in 3 prostate cell lines with any remedies at any exposure time. There was a 23% reduction in tumor incidence (P<.0001), and for animals with tumors, there was a 38% reduction in tumor volume in homeopathy-treated animals versus controls (P<.02). At time of killing, experimental animals with tumors had a 13% lower average tumor weight (P<.05). Tumors in these treated animals showed a 19% increase in apoptotic cell death (P<.05) and reduced PCNA-positive cells. CONCLUSIONS: The findings indicate that selected homeopathic remedies for the present study have no direct cellular anticancer effects but appear to significantly slow the progression of cancer and reduce cancer incidence and mortality in Copenhagen rats injected with MAT-LyLu prostate cancer cells.

Previously, we studied the antioxidant potential of Chaga mushroom [Inonotus obliquus (persoon) Pilat] extracts and isolated several small (poly)phenolic compounds as the major antioxidant components in the 80% methanol (MeOH) extract. In the present study, these isolated phenolic ingredients together with several other types of Chaga extracts were examined for cytotoxic effects against normal (IMR90) and cancer (A549, PA-1, U937, and HL-60) cell lines. Results revealed decoctions from both the fruiting body (FB) and sclerotium (ST) parts of Chaga, especially the ST part, showed considerable cytotoxicity toward tumor cells, but the cytotoxicity appeared to be stronger against normal cells than cancer cells. The 80% MeOH ST extract also showed the same trend. On the other hand, the 80% MeOH extract of FB showed significant cytotoxicity towards tumor cell lines without affecting normal cells, for example, the 50% lethal dose was 49.4 +/- 2.9 microg/mL for PA-1 cells versus 123.6 +/- 13.8 microg/mL for normal cells. The phenolic components isolated from the 80% MeOH extracts had markedly greater cancer cell toxicity than the extracts themselves. In particular, two out of seven compounds showed strong cytotoxicity towards several tumor cell lines without giving rise to significant cell toxicity toward normal cells. For example, the 50% lethal dose for 3,4-dihydroxybenzalacetone was 12.2 micromol/L in PA-1 cells but was 272.8 micromol/L in IMR90 cells. Fluorescence-activated cell sorting analysis further revealed these phenolic ingredients have high potentiality for apoptosis induction in PA-1 cells.

The main chemical component of cannabis, cannabidiol (CBD), has been shown to have antitumor properties. The present study examined the in vitro effects of CBD on human gastric cancer SGC-7901 cells. We found that CBD significantly inhibited the proliferation and colony formation of SGC-7901 cells. Further investigation showed that CBD significantly upregulated ataxia telangiectasia-mutated gene (ATM) and p53 protein expression and downregulated p21 protein expression in SGC-7901 cells, which subsequently inhibited the levels of CDK2 and cyclin E, thereby resulting in cell cycle arrest at the G0-G1 phase. In addition, CBD significantly increased Bax expression levels, decreased Bcl-2 expression levels and mitochondrial membrane potential, and then upregulated the levels of cleaved caspase-3 and cleaved caspase-9, thereby inducing apoptosis in SGC-7901 cells. Finally, we found that intracellular reactive oxygen species (ROS) increased after CBD treatment. These results indicated that CBD could induce G0-G1 phase cell cycle arrest and apoptosis by increasing ROS production, leading to the inhibition of SGC-7901 cell proliferation, thereby suggesting that CBD may have therapeutic effects on gastric cancer.

Kaposi sarcoma is the most common neoplasm caused by Kaposi sarcoma-associated herpesvirus (KSHV). It is prevalent among the elderly in the Mediterranean, inhabitants of sub-Saharan Africa, and immunocompromised individuals such as organ transplant recipients and AIDS patients. Current treatments for Kaposi sarcoma can inhibit tumor growth but are not able to eliminate KSHV from the host. When the host's immune system weakens, KSHV begins to replicate again, and active tumor growth ensues. New therapeutic approaches are needed. Cannabidiol (CBD), a plant-derived cannabinoid, exhibits promising antitumor effects without inducing psychoactive side effects. CBD is emerging as a novel therapeutic for various disorders, including cancer. In this study, we investigated the effects of CBD both on the infection of endothelial cells (ECs) by KSHV and on the growth and apoptosis of KSHV-infected ECs, an in vitro model for the transformation of normal endothelium to Kaposi sarcoma. While CBD did not affect the efficiency with which KSHV infected ECs, it reduced proliferation and induced apoptosis in those infected by the virus. CBD inhibited the expression of KSHV viral G protein-coupled receptor (vGPCR), its agonist, the chemokine growth-regulated proteinα (GRO-α), vascular endothelial growth factor receptor 3 (VEGFR-3), and the VEGFR-3 ligand, vascular endothelial growth factor C (VEGF-C). This suggests a potential mechanism by which CBD exerts its effects on KSHV-infected endothelium and supports the further examination of CBD as a novel targeted agent for the treatment of Kaposi sarcoma.

In the current study, we examined the effects of the nonpsychoactive cannabinoid, cannabidiol, on the induction of apoptosis in leukemia cells. Exposure of leukemia cells to cannabidiol led to cannabinoid receptor 2 (CB2)-mediated reduction in cell viability and induction in apoptosis. Furthermore, cannabidiol treatment led to a significant decrease in tumor burden and an increase in apoptotic tumors in vivo. From a mechanistic standpoint, cannabidiol exposure resulted in activation of caspase-8, caspase-9, and caspase-3, cleavage of poly(ADP-ribose) polymerase, and a decrease in full-length Bid, suggesting possible cross-talk between the intrinsic and extrinsic apoptotic pathways. The role of the mitochondria was further suggested as exposure to cannabidiol led to loss of mitochondrial membrane potential and release of cytochrome c. It is noteworthy that cannabidiol exposure led to an increase in reactive oxygen species (ROS) production as well as an increase in the expression of the NAD(P)H oxidases Nox4 and p22(phox). Furthermore, cannabidiol-induced apoptosis and reactive oxygen species (ROS) levels could be blocked by treatment with the ROS scavengers or the NAD(P)H oxidase inhibitors. Finally, cannabidiol exposure led to a decrease in the levels of p-p38 mitogen-activated protein kinase, which could be blocked by treatment with a CB2-selective antagonist or ROS scavenger. Together, the results from this study reveal that cannabidiol, acting through CB2 and regulation of Nox4 and p22(phox) expression, may be a novel and highly selective treatment for leukemia.

Treatment options specifically targeting tumour cells are urgently needed in order to reduce the side effects accompanied by chemo- or radiotherapy. Differences in subcellular structure between tumour and normal cells determine their specific elasticity. These structural differences can be utilised by low-frequency ultrasound in order to specifically induce cytotoxicity of tumour cells. For further evaluation, we combined in silico FEM (finite element method) analyses and in vitro assays to bolster the significance of low-frequency ultrasound for tumour treatment. FEM simulations were able to calculate the first resonance frequency of MCF7 breast tumour cells at 21 kHz in contrast to 34 kHz for the MCF10A normal breast cells, which was due to the higher elasticity and larger size of MCF7 cells. For experimental validation of the in silico-determined resonance frequencies, equipment for ultrasonic irradiation with distinct frequencies was constructed. Differences for both cell lines in their response to low-frequent ultrasonic treatment were corroborated in 2D and in 3D cell culture assays. Treatment with ~ 24.5 kHz induced the death of MCF7 cells and MDA-MB-231 metastases cells possessing a similar elasticity; frequencies of>29 kHz resulted in cytotoxicity of MCF10A. Fractionated treatments by ultrasonic irradiation of suspension myeloid HL60 cells resulted in a significant decrease of viable cells, mostly significant after threefold irradiation in intervals of 3 h. Most importantly in regard to a clinical application, combined ultrasonic treatment and chemotherapy with paclitaxel showed a significantly increased killing of MCF7 cells compared to both monotherapies. In summary, we were able to determine for the first time for different tumour cell lines a specific frequency of low-intensity ultrasound for induction of cell ablation. The cytotoxic effect of ultrasonic irradiation could be increased by either fractionated treatment or in combination with chemotherapy. Thus, our results will open new perspectives in tumour treatment.

Sulindac has anti-neoplastic properties against colorectal cancers; however, its use as a chemopreventive agent has been limited due to toxicity and efficacy concerns. Combinatorial treatment of colorectal cancers has been attempted to maximize anti-cancer efficacy with minimal side effects by administrating NSAIDs in combination with other inhibitory compounds or drugs such as L-ascorbic acid (vitamin C), which is known to exhibit cytotoxicity towards various cancer cells at high concentrations. In this study, we evaluated a combinatorial strategy utilizing sulindac and vitamin C. The death of HCT116 cells upon combination therapy occurred via a p53-mediated mechanism. The combination therapeutic resistance developed in isogenic p53 null HCT116 cells and siRNA-mediated p53 knockdown HCT116 cells, but the exogenous expression of p53 in p53 null isogenic cells resulted in the induction of cell death. In addition, we investigated an increased level of intracellular ROS (reactive oxygen species), which was preceded by p53 activation. The expression level of PUMA (p53-upregulated modulator of apoptosis), but not Bim, was significantly increased in HCT116 cells in response to the combination treatment. Taken together, our results demonstrate that combination therapy with sulindac and vitamin C could be a novel anti-cancer therapeutic strategy for p53 wild type colon cancers.

The medicinal mushroom Inonotus obliquus is a traditional and widely used multi-functional fungus. Hot water (50 degrees C, 70 degrees C, and 80 degrees C) and ethanol crude extracts of I. obliquus were investigated for their antioxidant activity with superoxide dismutase (SOD) and (1,1-diphenyl-2-picryhydrazyl) (DPPH) radical-scavenging activity assays. We also investigated the antiproliferative effects and ability of the extracts to induce apoptosis in human colon cancer DLD-1 cells. Among the four extracts, the ethanol extract (EE) exhibited the strongest SOD-like activity and antiproliferative effect on DLD-1 cells, and exposure to the EE resulted in the induction of apoptosis, whereas no apoptosis was observed in DLD-1 cells exposed to the hot water extracts (HWEs). HWE at 70 degrees C (HWE70) exhibited the strongest DPPH radical-scavenging activity (EC50, 126 microg/ml), whereas the EE showed the weakest activity (EC50, 224 microg/ml). The different biological activities among the four extracts may be attributed to differences in their chemical composition, partially supported by polysaccharide, protein and phenolic content, and the 1H-NMR spectra.