Furanocoumarins as Enhancers of Antitumor Potential of Sorafenib and LY294002 toward Human Glioma Cells In Vitro

Furanocoumarins are naturally occurring compounds in the plant world, characterized by low molecular weight, simple chemical structure, and high solubility in most organic solvents. Additionally, they have a broad spectrum of activity, and their properties depend on the location and type of attached substituents. Therefore, the aim of our study was to investigate the anticancer activity of furanocoumarins (imperatorin, isoimperatorin, bergapten, and xanthotoxin) in relation to human glioblastoma multiforme (T98G) and anaplastic astrocytoma (MOGGCCM) cell lines. The tested compounds were used for the first time in combination with LY294002 (PI3K inhibitor) and sorafenib (Raf inhibitor). Apoptosis, autophagy, and necrosis were identified microscopically after straining with Hoechst 33342, acridine orange, and propidium iodide, respectively. The levels of caspase 3 and Beclin 1 were estimated by immunoblotting and for the blocking of Raf and PI3K kinases, the transfection with specific siRNA was used. The scratch test was used to assess the migration potential of glioma cells. Our studies showed that the anticancer activity of furanocoumarins strictly depended on the presence, type, and location of substituents. The obtained results suggest that achieving higher pro-apoptotic activity is determined by the presence of an isoprenyl moiety at the C8 position of the coumarin skeleton. In both anaplastic astrocytoma and glioblastoma, imperatorin was the most effective in induction apoptosis. Furthermore, the usage of imperatorin, alone and in combination with sorafenib or LY294002, decreased the migratory potential of MOGGCCM and T98G cells.

The Role of Bcl-2 and Beclin-1 Complex in "Switching" between Apoptosis and Autophagy in Human Glioma Cells upon LY294002 and Sorafenib Treatment

BACKGROUND

Gliomas are the most malignant tumors of the central nervous system. One of the factors in their high drug resistance is avoiding programmed death (PCD) induction. This is related to the overexpression of intracellular survival pathways: PI3K-Akt/PKB-mTOR and Ras-Raf-MEK-ERK. Apoptosis and autophagy are co-existing processes due to the interactions between Bcl-2 and beclin-1 proteins. Their complex may be a molecular "toggle-switch" between PCD types. The aim of this research was to investigate the role of Bcl-2:beclin-1 complex in glioma cell elimination through the combined action of LY294002 and sorafenib.

METHODS

Drug cytotoxicity was estimated with an MTT test. The type of cell death was evaluated using variant microscopy techniques (fluorochrome staining, immunocytochemistry, and transmission electron microscopy), as well as the Bcl-2:beclin-1 complex formation and protein localization. Molecular analysis of PCD indicators was conducted through immunoblotting, immunoprecipitation, and ELISA testing. SiRNA was used to block Bcl-2 and beclin-1 expression.

RESULTS

The results showed the inhibitors used in simultaneous application resulted in Bcl-2:beclin-1 complex formation and apoptosis becoming dominant. This was accompanied by changes in the location of the tested proteins.

CONCLUSIONS

"Switching" between apoptosis and autophagy using PI3K and Raf inhibitors with Bcl-2:beclin-1 complex formation opens new therapeutic perspectives against gliomas.

Heterogeneous Cellular Response of Primary and Metastatic Human Gastric Adenocarcinoma Cell Lines to Magnoflorine and Its Additive Interaction with Docetaxel

Gastric cancer is the most common cancer and remains the leading cause of cancer death worldwide. In this study, the anticancer action of magnoflorine isolated via counter-current chromatography from the methanolic extract of Berberis vulgaris root against gastric cancer in models of primary ACC-201 and AGS and metastatic MKN-74 and NCI-N87 cell lines was analyzed. Cell viability and proliferation were tested through the use of MTT and BrdU tests, respectively. Cell cycle progression and apoptosis were evaluated using flow cytometry. The interaction of magnoflorine and docetaxel has been examined through isobolographic analysis. Moreover, potential toxicity was verified in zebrafish in an in vivo model. Gastric cancer cell lines revealed different responses to magnoflorine treatment with regard to viability/proliferation, apoptosis induction and cell cycle inhibition without any undesirable changes in the development of larval zebrafish at the tested concentrations. What is more, magnoflorine in combination with docetaxel produced an additive pharmacological interaction in all studied gastric cancer cell lines, which may suggest a complementary mechanism of action of both compounds. Taken together, these findings provide a foundation for the possibility of magnoflorine as a potential therapeutic approach for gastric cancer and merits further investigation, which may pave the way for clinical uses of magnoflorine.

Synergism of antiproliferative effects of young green barley and chlorella water extracts against human breast cancer cells

INTRODUCTION AND OBJECTIVE

Breast cancer is the most common type of tumour in terms of incidence and mortality among women. In the light of recent data that has revealed the beneficial impact of increasing plant-based food consumption on the risk of breast cancer, the use of young green barley and chlorella, the chemopreventive properties of which have been previously reported, seems to be a reasonable therapeutic strategy in this type of cancer. Nevertheless, there are only a few scientific reports focused on the influence of the mentioned products on breast cancer development; thus, the aim of the study was to enrich knowledge resources in this area.

MATERIAL AND METHODS

The chemopreventive effect of water extracts of chlorella (CH) and young green barley (YGB) and their mixture (MIX) was investigated in human breast adenocarcinoma T47D cells and human skin fibroblasts HSF by LDH, MTT and BrdU assays. Changes in cell morphology in response to tested extracts were examined in light microscopy.

RESULTS

Tested extracts were not toxic against HSF and did not affect their proliferation and morphology. Simultaneously, extracts increased the permeability of T47D cell membranes and inhibited their proliferation. Microscopic observation confirmed the results of biochemical assays and additionally suggested necrosis induction in T47D cells in response to tested compounds. Obtained results demonstrated that MIX induced stronger beneficial changes than their components.

CONCLUSIONS

The study revealed the chemopreventive properties of the investigated green food products against breast cancer cells, without any side-effects in human skin fibroblasts. The beneficial properties discovered of the tested extracts on cancer cells enhanced by their concomitant administration, and in the case of antiproliferative effects YGB and CH, revealed synergism of action.

(1→3)-α-d-Glucooligosaccharides Increase the Killing Capacity of NK Cells against Selected Human Colon Cancer Cells

Despite the progress of medicine, colorectal cancer has occupied one of the highest positions in the rankings of cancer morbidity and mortality for many years. Thus, alternative methods of its treatment are sought. One of the newer therapeutic strategies is immunotherapy based on NK cells (natural killers), which are the body's first line of defense against cancer. The aim of the study was to verify the possibility of using (1→3)-α-d-glucooligosaccharides (GOSs) obtained via acid hydrolysis of (1→3)-α-d-glucan from the fruiting body of Laetiporus sulphureus to improve the anticancer effect of NK-92 cells, with proven clinical utility, against selected human colon adenocarcinoma cell lines LS180 and HT-29. The study revealed that the investigated oligosaccharides significantly enhanced the ability of NK-92 cells to eliminate the examined colon cancer cells, mostly by an increase in their cytotoxic activity. The most significant effect was observed in LS180 and HT-29 cells exposed to a two-times higher quantity of NK cells activated by 500 µg/mL GOS, wherein NK-92 killing properties increased for 20.5% (p < 0.001) and 24.8% (p < 0.001), respectively. The beneficial impact of (1→3)-α-d-glucooligosaccharides on the anticancer properties of NK-92 suggests their use in colon cancer immunotherapy as adjuvants; however, the obtained data require further investigation and confirmation.

Binge-like mephedrone treatment induces memory impairment concomitant with brain kynurenic acid reduction in mice

While mephedrone (4-methylmethcathinone), a synthetic cathinone derivative, is widely abused by adolescents and young adults, the knowledge about its long-term effects on memory processes is limited. Kynurenic acid (KYNA) is a neuroactive metabolite of the kynurenine pathway of tryptophan degradation. KYNA is considered an important endogenous modulator influencing physiological and pathological processes, including learning and memory processes. The aim of this study was to determine whether (A) binge-like mephedrone administration (10.0 and 30.0 mg/kg, intraperitoneally, in 4 doses separated by 2 h) induces memory impairments, assessed 2, 8 and 15 days after mephedrone cessation in the passive avoidance test in mice, and whether (B) KYNA is involved in these memory processes. To clarify the role of KYNA in the mephedrone effects, its level in the murine brain in vivo, and in cortical slices in vitro, as well as the activities of kynurenine aminotransferases (KATs) I and II were assessed. Furthermore, cell line experiments were conducted to investigate the effects of mephedrone on normal human brain cells. Our results showed memory impairments 8 and 15 days after binge-like mephedrone administration. At the same time, reduction in the KYNA level in the murine brain was noted. In vitro studies showed no effect of mephedrone on the production of KYNA in cortical slices or on the activity of the KAT I and II enzymes. Finally, exposure of normal cells to mephedrone in vitro resulted in a modest reduction of cell viability and proliferation.

Impact of phytochemicals and plant extracts on viability and proliferation of NK cell line NK-92 - a closer look at immunomodulatory properties of goji berries extract in human colon cancer cells

INTRODUCTION

Due to the fact that lymphocytes NK (natural killer cells) are the first line of defence of the body against cancer, one of the goals of modern immunotherapy is the enhancement of their natural activities for the effective recognition, detection, and elimination of cancer cells.

OBJECTIVE

The aim of the study was to evaluate the influence of selected phytochemicals (curcumin and resveratrol) and plant extracts (chlorella and goji berries) on NK cells viability and proliferation, as well as cytotoxic activity against colon cancer - one of the most common cancer worldwide.

MATERIAL AND METHODS

The impact of phytochemicals, viability and proliferation of plant extracts on NK cells was examined in NK-92 cells using both LDH and MTT assays. The immunomodulatory properties of selected compounds were tested against human colon cancer cell line LS180 using the MTT test.

RESULTS

Extracts of chlorella and goji berries significantly increased NK cell proliferation, while curcumin and resveratrol did not affect this process. Curcumin, as well as extracts of chlorella and goji berries, did not impact NK viability, while resveratrol significantly increased it. LDH test revealed the cytotoxic effect of chlorella extract and curcumin in NK-92 cell cultures. On the contrary, goji berries extract significantly decreased LDH level, while resveratrol did not affect the integrity of NK cell membranes. Studies conducted in co-cultures NK cells, also directly eliminated colon cancer cells.

CONCLUSIONS

Performed studies revealed immunomodulatory properties of goji berries extract, which improved viability and proliferation of NK cells, and above all, significantly increased their ability to recognize and eliminate colon cancer cells.

Involvement of PI3K Pathway in Glioma Cell Resistance to Temozolomide Treatment

The aim of the study was to investigate the anticancer potential of LY294002 (PI3K inhibitor) and temozolomide using glioblastoma multiforme (T98G) and anaplastic astrocytoma (MOGGCCM) cells. Apoptosis, autophagy, necrosis, and granules in the cytoplasm were identified microscopically (fluorescence and electron microscopes). The mitochondrial membrane potential was studied by flow cytometry. The activity of caspases 3, 8, and 9 and Akt was evaluated fluorometrically, while the expression of Beclin 1, PI3K, Akt, mTOR, caspase 12, and Hsp27 was determined by immunoblotting. SiRNA was used to block Hsp27 and PI3K expression. Cell migration and localization of Hsp27 were tested with the wound healing assay and immunocytochemistry, respectively. LY294002 effectively diminished the migratory potential and increased programmed death of T98G and MOGGCCM. Autophagy was dominant in MOGGCCM, while apoptosis was dominant in T98G. LY294002 with temozolomide did not potentiate cell death but redirected autophagy toward apoptosis, which was correlated with ER stress. A similar effect was observed after blocking PI3K expression with siRNA. Transfection with Hsp27 siRNA significantly increased apoptosis related to ER stress. Our results indicate that inhibition of the PI3K/Akt/mTOR pathway sensitizes glioma cells to apoptosis upon temozolomide treatment, which was correlated with ER stress. Hsp27 increases the resistance of glioma cells to cell death upon temozolomide treatment.

Promising Potential of Crude Polysaccharides from Sparassis crispa against Colon Cancer: An In Vitro Study

The aim of the present study was to evaluate in vitro the beneficial potential of crude polysaccharides from S. crispa (CPS) in one of the most common cancer types-colon cancer. The determination of the chemical composition of CPS has revealed that it contains mostly carbohydrates, while proteins or phenolics are present only in trace amounts. 1H NMR and GC-MS methods were used for the structural analysis of CPS. Biological activity including anticancer, anti-inflammatory and antioxidant properties of CPS was investigated. CPS was found to be non-toxic to normal human colon epithelial CCD841 CoN cells. Simultaneously, they destroyed membrane integrity as well as inhibited the proliferation of human colon cancer cell lines: Caco-2, LS180 and HT-29. Antioxidant activity was determined by various methods and revealed the moderate potential of CPS. The enzymatic assays revealed no influence of CPS on xanthine oxidase and the inhibition of catalase activity. Moreover, pro-inflammatory enzymes such as cyclooxygenase-2 or lipooxygenase were inhibited by CPS. Therefore, it may be suggested that S. crispa is a valuable part of the regular human diet, which may contribute to a reduction in the risk of colon cancer, and possess promising activities encouraging further studies regarding its potential use as chemopreventive and therapeutic agent in more invasive stages of this type of cancer.

Enhancement of chemopreventive properties of young green barley and chlorella extracts used together against colon cancer cells

INTRODUCTION AND OBJECTIVE

Young green barley and chlorella are listed as a panacea for a whole range of disorders, including diabetes, cardiovascular disease, infections, and hypercholesterolaemia. The first reports have appeared presenting the anticancer properties of these products. The present study is an attempt to extend this knowledge with particular emphasis on the possibility of using young green barley, chlorella, and their combination in colon cancer chemoprevention.

MATERIAL AND METHODS

Extracts of young green barley (YB) and chlorella (CH), as well as their combination MIX (YB+CH; 1:1), were examined. The influence of the extracts on viability and proliferation of human colon epithelial CCD841 CoN cells was analyzed by LDH and MTT assays. Anticancer properties of extracts were screened on human colon adenocarcinoma cell line HT-29 by MTT and BrdU assays. Changes in cells morphology in response to extracts were investigated after May-Grünwald-Giemsa staining.

RESULTS

Extracts used together or separately did not affect the viability and proliferation of CCD841 CoN cells. Simultaneously, YB, CH and MIX inhibited proliferation of HT-29 cells in a dose-dependent manner. Furthermore changes in the morphology of HT-29 cells treated with YB, CH and MIX suggested necrosis induction. Performed studies also revealed that MIX induced a stronger antiproliferative effect than their individual ingredients; however, the discovered enhancement of anticancer properties was weaker than the sum of the effects of YB and CH creating MIX.

CONCLUSIONS

The study demonstrates great chemopreventive properties of young green barley and chlorella water extracts and their combination in in vitro model of colon cancer. The anticancer properties of the investigated extracts were significantly enhanced after combining, without an increase of their toxicity against normal cells.

Coumarins modulate the anti-glioma properties of temozolomide

In the recent years, coumarin bioactive compounds have been identified to posess anticancer properties. Therefore, the aim of the present study was to investigate for the first time the efficacy of osthole, umbelliferone, esculin, and 4-hydroxycoumarin, alone and in combination with Temozolomide, in the elimination of deadly brain tumors, anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM) cells via programmed death. Our results indicated that osthole, umbelliferone, esculin, and 4-hydroxycoumarin initiated mainly apoptosis in the T98G and MOGGCCM cells. Osthole was the most effective. It also initiated autophagy in a small percentage of the cell population. The co-incubation with Temozolomide did not increase the pro-apoptotic potential of natural compounds but decreased the level of autophagy in the T98G cells. Apoptosis was associated with reduced mitochondrial membrane potential, activation of caspase 3, inhibition of Bcl-2 expression and the presence of a Bcl-2/Beclin 1. Blocking of Bcl-2 expression resulted in promotion of apoptosis, but not autophagy, in the MOGGCCM and T98G lines. It also sensitized astrocytoma cells, but not GBM, to the combined osthole and TMZ treatment, which was correlated with a reduced level of Beclin 1 and increased expression of caspase 3. Osthole and TMZ, alone and in combination, inhibited the migratory phenotype of the GBM and AA cells. In summary, our results indicated that osthole effectively eliminated glioma cells via apoptosis, what was correlated with Bcl-2/Beclin 1 complex formation. Considering the anti-migratory effect, osthole and Temozolomide display antiglioma potential but it needs further extensive studies.

Pantoea agglomerans chronic exposure induces epithelial-mesenchymal transition in human lung epithelial cells and mice lungs

Pantoea agglomerans is gram-negative bacteria widely distributed in nature. It predominates in inhalable dust from grain, herbs, and flax, and was identified as the most important cause of hypersensitivity pneumonitis (HP) in eastern Poland. To better understand the molecular mechanism of HP development studies focused on the interactions between P. agglomerans and alveolar epithelial cells as well as lung tissue with particular emphasis on the epithelial-mesenchymal transition (EMT). The studies were conducted on human normal lung epithelial NL20 cells and mice strain C57BL/6J. Cells and mice underwent chronic exposure to saline extract of P. agglomerans (SE-PA). Morphological changes were evaluated under light microscopy, the concentration of fibrosis markers was examined by the ELISA method, while the expression of genes involved in EMT was evaluated by RealTime PCR. During incubation with SE-PA epithelial cells underwent conversion and assumed fibroblast phenotype characterized by a decrease in epithelial cells markers (CDH1, CLDN1, JUP) and increase in mesenchymal cells markers (FN1, VIM, CDH2). Mice lungs collected after 14 days of SE-PA treatment revealed inflammation with marked lymphocytes infiltration. The intensified inflammatory process accompanied by increased proliferation of fibrous connective tissue was noted in mice lungs after 28 days of SE-PA exposure. Histological changes correlated with an increase of fibrosis markers (hydroxyproline, collagens), downregulation of epithelial markers (Cdh1, Cldn1, Jup, Ocln) and upregulation of myofibroblasts markers (Acta2, Cdh2, Fn1, Vim). Obtained results revealed SE-PA ability to induce EMT in human lung epithelial cells and mice lung tissue, with the scale of changes proportional to the time of treatment.

Prostate and breast cancer cells death induced by xanthohumol investigated with Fourier transform infrared spectroscopy

Fourier Transform Infrared spectroscopy was applied to detect in vitro cell death induced in prostate (PC-3) and breast (T47D) cancer cell lines treated with xanthohumol (XN). After incubation of the cancer cells with XN, specific spectral shifts in the infrared spectra arising from selected cellular components were identified that reflected biochemical changes characteristic for apoptosis and necrosis. Detailed analysis of specific absorbance intensity ratios revealed the compositional changes in the secondary structure of proteins and membrane lipids. In this study, for the first time we examined the changes in these molecular components and linked them to deduce the involvement of molecular mechanisms in the XN-induced death of the selected cancer cells. We showed that XN concentration-dependent changes were attributed to phospholipid ester carbonyl groups, especially in the case of T47D cells, suggesting that XN acts as an inhibitor of cell proliferation. Additionally, we observed distinct changes in the region assigned to the absorption of DNA, which were correlated with a specific marker of cell death and dependent on the XN dose and the type of cancer cells. The microscopic observation and flow cytometry analysis revealed that the decrease in cancer cell viability was mainly related to the induction of necrotic cell death. Moreover, the T47D cells were slightly more sensitive to XN than the PC-3 cells. Considering the results obtained, it can be assumed that apoptosis and necrosis induced by XN may contribute to the anti-proliferative and cytotoxic properties of this flavonoid against cancer cell lines PC-3 and T47D.

Pro-apoptotic action of protein-carbohydrate fraction isolated from coelomic fluid of the earthworm Dendrobaena veneta against human colon adenocarcinoma cells

Earthworm coelomic fluid (CF) is known as a rich source of various bioactive compounds with promising anticancer features. However, it has been demonstrated that CF affects functionality of both, cancer and normal cells. This non-selective activity causes a major problem for medical application of CF. In this study, we present the anticancer activity of the active protein-carbohydrate fraction (AF) isolated from thermally treated CF of earthworm Dendrobaena veneta. The in vitro effect of the AF was examined in human colon model including normal human colon epithelium (CCD 841 CoTr) and human colon adenocarcinoma (HT-29 and LS180) cell lines. We investigated the impact of AF on cell viability neutral red and lactate dehydrogenase assays, morphology May-Grünwald-Giemsa staining assay proliferation MTT tetrazolium salt and BrdU incorporation assays as well as cell cycle progression propidium iodide/RNase staining and the activity of human 20S proteasome the hydrolysis of AMC from a Suc-LLVY-AMC peptide substrate. Additionally, the influence of AF on apoptosis was examined in HT-29 cells by Annexin V/PI, Hoechst 33342 staining and active caspase-3 assays. Our investigation demonstrated that AF at the tested concentration range does not affect the viability and morphology of CCD 841 CoTr cells. Simultaneously, AF inhibits human 20S proteasome activity as well as significantly decreases mitochondrial metabolism, disturbs cell cycle and induces apoptosis via activation of procaspase-3 in HT-29 cancer cells. Obtained results demonstrate the antiproliferative and proapoptotic activity of AF that can be useful in developing therapeutic strategies to treat human colon cancer.

Betulin Promotes Differentiation of Human Osteoblasts In Vitro and Exerts an Osteoinductive Effect on the hFOB 1.19 Cell Line Through Activation of JNK, ERK1/2, and mTOR Kinases

Although betulin (BET), a naturally occurring pentacyclic triterpene, has a variety of biological activities, its osteogenic potential has not been investigated so far. The aim of this study was to assess the effect of BET on differentiation of human osteoblasts (hFOB 1.19 and Saos-2 cells) in vitro in osteogenic (with ascorbic acid as an osteogenic supplement) and osteoinductive (without an additional osteogenic supplement) conditions. Osteoblast differentiation was evaluated based on the mRNA expression (RT-qPCR) of Runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), type I collagen-α1 (COL1A1), and osteopontin (OPN). Additionally, ALP activity and production of COL1A1 (western blot analysis) and OPN (ELISA) were evaluated. The level of mineralization (calcium accumulation) was determined with Alizarin red S staining. BET upregulated the mRNA level of RUNX2 and the expression of other osteoblast differentiation markers in both cell lines (except the influence of BET on ALP expression/activity in the Saos-2 cells). Moreover, it increased mineralization in both cell lines in the osteogenic conditions. BET also increased the mRNA level of osteoblast differentiation markers in both cell lines (except for ALP in the Saos-2 cells) in the osteoinductive conditions, which was accompanied with increased matrix mineralization. The osteoinductive activity of BET in the hFOB 1.19 cells was probably mediated via activation of MAPKs (JNK and ERK1/2) and mTOR, as the specific inhibitors of these kinases abolished the BET-induced osteoblast differentiation. Our results suggest that BET has the potential to enhance osteogenesis.

AMPA Receptor Antagonist CFM-2 Decreases Survivin Expression in Cancer Cells

BACKGROUND

Glutamate receptors are widely expressed in different types of cancer cells. α-Amino-3- hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors are ionotropic glutamate receptors which are coupled to intracellular signaling pathways that influence cancer cell survival, proliferation, and migration. Blockade of AMPA receptors by pharmacologic compounds may potentially constitute an effective tool in anticancer treatment strategies.

METHOD

Here we investigated the impact of the AMPA receptor antagonist CFM-2 on the expression of the protein survivin, which is known to promote cancer cell survival and proliferation. We show that CFM-2 inhibits survivin expression at mRNA and protein levels and decreases the viability of cancer cells. Using a stably transfected cell line which overexpresses survivin, we demonstrate that over-expression of survivin enhances cancer cell viability and attenuates CFM-2-mediated inhibition of cancer cell growth.

RESULT

These findings point towards suppression of survivin expression as a new mechanism contributing to anticancer effects of AMPA antagonists.

Riluzole Inhibits Proliferation, Migration and Cell Cycle Progression and Induces Apoptosis in Tumor Cells of Various Origins

BACKGROUND

Regardless of contemporary improvements in cancer treatment, the results of drug treatment are not always efficacious. Thus, the development of novel approaches that affect cancer cell-specific metabolic pathways is needed. Since much evidence has shown that tumor cell proliferation and motility are stimulated by glutamate via activation of its receptors, use of antagonists to these receptors may be the key to control cancer cell progression. Riluzole noncompetitive metabotropic glutamate receptor 1 (mGluR1) antagonist, commonly used to treat patients with amyotrophic lateral sclerosis (ALS), has shown some antineoplastic properties against melanoma, breast and prostate cancer. Yet little is known about its molecular mode of action.

AIMS

The current study aims at evaluating the abilities of Riluzole to inhibit proliferation of several cancer cell lines, as well as resolve the mechanism of its action.

METHOD

We demonstrated antiproliferative and antimigrative properties of Riluzole in rhabdomyosarcomamedulloblastoma, neuroblastoma, astrocytoma, glioma, colon cancer, lung cancer, thyroid carcinoma, leukemia, erythroleukemia and multiple myeloma. Our studies revealed apoptosis induction and G2-M cell cycle arrest in Riluzole treated A549, C6 and HT-29 cells.

RESULT

At the molecular level, we found that these cells treated with Riluzole had a decrease of Cyclin B and an increase of p21 Waf1/Cip1 and p53 expression. We also observed an enhancement of CDK1 and Chk2 phosphorylation. Reported changes may suggest the involvement of these proteins in G2-M arrest, observed in flow cytometry analysis. These data indicated the potential use of Riluzole in the treatment of different types of cancers.

Chemopreventive properties of young green barley extracts in in vitro model of colon cancer

INTRODUCTION AND OBJECTIVE

Young green barley is the most valuable source of nutrients and bioactive substances. It has a broad spectrum of health-promoting properties such as antioxidant, anti-inflammatory, hypoglycaemic, anti-depressant, anti-atherosclerotic and anticancer. The presented study is an attempt to extend this knowledge with particular emphasis on the possibility of using green barley in colon cancer prevention.

MATERIAL AND METHODS

Extracts were prepared on the basis of two commercial products: ground dried barley grass (YGB INT) and powder of young green barley juice (YGB GW). Their influence on colon epithelial cells (CCD841 CoN) viability and proliferation were analyzed by LDH and MTT assays. Anticancer properties of extracts were screened on colon cancer cell lines (LS180, HT-29) by MTT and BrdU assays. Changes in cells morphology induced by extracts were investigated after May-Grünwald-Giemsa staining.

RESULTS

Tested extracts were not toxic against CCD841 CoN and did not affected their proliferation or morphology (LDH test, MTT test, microscopy observation). The MTT revealed that extracts significantly inhibited proliferation of colon cancer cells in a dose-dependent manner. Results of BrdU test confirmed antiproliferative properties of extracts, but opposite to MTT test, indicated YGB GW as a better anticancer agent. Light microscopy observation proved the data obtained from both MTT and BrdU tests and additionally suggested the ability of the extracts to induce necrosis in LS180 and HT-29 cells.

CONCLUSIONS

The study demonstrated that YGB extracts specifically inhibit proliferation of colon cancer cells without any undesirable effect on colon epithelial cells. Obtained results will provide a rationele for the future development of dietary supplements which could be beneficial in colon cancer chemoprevention.

Lycopene, sulforaphane, quercetin, and curcumin applied together show improved antiproliferative potential in colon cancer cells in vitro

Lycopene, sulforaphane, quercetin, and curcumin, ingredients of daily diet, show significant anticancer and chemopreventive potential; however, no data are available showing thorough evaluation of jointly used phytochemicals on cancer cell proliferation. Here, we compare anticancer potential of mentioned substances applied separately or in combination (as MIX) by measuring mitochondrial activity (MTT test), DNA synthesis (BrdU test) and lactate dehydrogenase release (LDH test) in colon epithelial (CCD841 CoTr), and colon cancer (HT-29, LS174T) cells. Additive inhibitory effect of simultaneously used phytochemicals on cancer cells proliferation has been shown. In epithelial cells, tested combination effectively inhibited mitochondrial activity, but not DNA synthesis. LDH test revealed cytotoxicity of tested mixture against cancer cells without negative effect on normal cells. Furthermore, we demonstrated that MIX enhances antiproliferative effect of common cytostatics: 5-fluorouracil and cisplatin. Presented data suggest chemopreventive potential of the proposed combination of natural substances and their usefulness as adjuvant strategy during chemotherapy. PRACTICAL APPLICATIONS: Colorectal cancer is one of the most common causes of cancer death worldwide. Since its development and progression is strongly correlated with dietary habits, healthy diet as well as supplementation with proved anticancer agents seems to be reasonable strategy of colon cancer prevention and treatment. In the present study, we have focused on four natural compounds abundantly found in daily diet i.e., lycopene, sulforaphane, quercetin, and curcumin, with well established anticancer potential. Their individual and collective impact both on normal colon epithelium cells and colon cancer cells viability, growth, and proliferation was examined. Furthermore, activity of the substances combined as MIX to influence antiproliferative potential of commonly used in colon cancer treatment cytostatics, 5-fluorouracil, and cisplatin was verified. Proposed in the study combination of phytochemicals with experimentally proven antiproliferative activity may propose an effective strategy for prevention and treatment of colon cancer.

Mushroom small RNAs as potential anticancer agents: a closer look at Cantharellus cibarius proapoptotic and antiproliferative effects in colon cancer cells

Screening aimed at the evaluation of the presence of small RNAs with anticancer properties in Boletus spretus, B. pinophilus and Cantharellus cibarius, was conducted.

Branched mannans from the mushroom Cantharellus cibarius enhance the anticancer activity of natural killer cells against human cancers of lung and colon

Cantharellus cibarius branched mannans increase natural killer cells NK92 viability and proliferation and enhance their cytotoxicity against lung and colon cancer cells A549 and LS180, at the same time they do not affect lung and colon epithelial cells NL20 and CCD841 CoN.

Evaluation of the effect of 2-(2,4-dihydroxyphenyl)-4H-benzofuro[3,2-d][1,3]thiazin-4-one on colon cells and its anticancer potential

In this paper, we present the biological effect of the newly synthesized 2-(2,4-dihydroxyphenyl)-4H-benzofuro[3,2-d][1,3]thiazin-4-one (DPBT) on human colon adenocarcinoma cell lines (HT-29 and LS180). Additionally, DPBT cytotoxicity was examined in human colon epithelial cells (CCD 841 CoTr) and human skin fibroblasts (HSF). The studies revealed a significant decrease in the proliferation of cancer cells after exposure to DPBT at concentrations in the range of 10–100 µM. Additionally, DPBT was not toxic to normal CCD 841 CoTr and HSF cells at concentrations that induced inhibition of cancer cell proliferation. The nature of the anti-proliferative action of DPBT in the cell cycle progression in colon cancer cells and the expression of proteins involved in this process were examined by flow cytometry and western blotting, respectively. The investigations demonstrated higher sensitivity of LS180 than HT-29 to the DPBT treatment. The anti-proliferative action of DPBT in LS180 was attributed to cell cycle arrest in the G₁ phase via up-regulation of p27^KIP1 and down-regulation of cyclin D1 and CDK4 proteins.

Synthesis, Structure and Antiproliferative Activity of New pyrazolo[4,3- e]triazolo[4,5-b][1,2,4]triazine Derivatives

BACKGROUND

Triazoles and their fused derivatives are an important class of compounds that exhibit interesting biological properties, such as antiasthmatic, antimicrobial, antifungal, analgesic, antiallergic, antiinflammatory, herbicidal, plant growth regulative activity, and anti-HIV-1 activities. Moreover, anticancer activity of 1,2,4-triazole containing derivatives has been documented. Due to the fact a convenient approach toward polycyclic frameworks containing fused 1,2,4-triazoles was described.

OBJECTIVE

The objective of this article is the synthesis of new pyrazolo[4,3-e]triazolo[4,5- b][1,2,4]triazine derivatives with potential antiproliferative activity.

METHODS

Cancer cell proliferation was analysed by means of MTT assay after 96 h treatment. IC50 was calculated using computerized linear regression analysis of quantal log doseprobit functions, according to the method of Litchfield and Wilcoxon. X-ray data were collected on the Bruker SMART APEX II CCD diffractometer; The structure was solved by direct methods using SHELXS-2013 and refined by full-matrix least-squares with SHELXL-2014/7. All calculations were performed using WINGX version 2014.1 package.

RESULTS

The series of pyrazolo[4,3-e]triazolo[4,5-b][1,2,4]triazine derivatives were synthesized. MTT assay revealed that the compounds inhibited cancer cells growth at concentrations below 10 µM. The tested compounds showed higher antiproliferative activity than popular cytostatics cisplatin (lung carcinoma) and 5-fluorouracil (colon adenocarcinoma). X-ray examinations showed that final products in the crystalline phase have a linear form.

CONCLUSION

In the paper we have reported the synthesis and spectroscopic analysis of new condensed tricyclic derivatives of the pyrazolo[4,3-e]triazolo[4,5-b][1,2,4]triazine. MTT analysis revealed concentration-dependent decrease in lung A549 and colon LS180 cancer cells proliferation. In order to explain the molecular mechanisms involved in anticancer activity of pyrazolo[4,3- e]triazolo[4,5-b][1,2,4]triazine derivatives, our research will be continued.

The protective effects of silybin on the cytotoxicity of thiram in human, rat and chicken cell cultures

The study objective was a determination of thiram cytotoxicity and silybin cytoprotective activity in course of the fungicide impact on cell metabolism and membrane integrity. Firstly, human, rat, chicken hepatoma cells and rat myoblasts cultures were incubated with thiram. The results showed higher sensitivity of myoblasts on thiram exposure than the hepatoma cells. Among hepatoma cells, the chicken cultures were the most sensitive on the fungicide endangering. The mitochondrial activity was the most thiram affected function within all types the cell lines used. When silybin co-acted with thiram, an increase of the cell viability was recorded. The EC₅₀-values were higher for thiram subjected to interaction with silybin than the effect of alone thiram action. The interaction mode between the studied compounds shown by combination index (CI) represented an antagonistic or an additive nature and was depended on thiram concentration, type of the cells and the assay used. Moreover, the morphology changes were dependent on silybin presence in the cell cultures subjected to thiram impact at the same time. Staining with Hoechst 33342 and propidium ioidium revealed the apoptosis cell death in the incubation cultures. Definitely, the results have shown a potential of silybin to protect the cultured cells in course of cytotoxicity induced by thiram. However, future studies taking into account other endpoints of thiram cytotoxicity pathways including species differences and the cytoprotection efficacy could be of interest.

Quinaldic acid in synovial fluid of patients with rheumatoid arthritis and osteoarthritis and its effect on synoviocytes in vitro

BACKGROUND

Previously, we have demonstrated that kynurenic acid (KYNA), an endogenous metabolite of tryptophan formed along kynurenine pathway, is present in synovial fluid of rheumatoid arthritis (RA) and osteoarthritis (OA) patients. In this study, the goal was to investigate the presence of quinaldic acid (QUDA), a putative metabolite of KYNA, in synovial fluid of RA and OA patients.

METHODS

The effect of QUDA on proliferation and motility of synovial fibroblasts and its interaction with KYNA were determined in vitro. The study was conducted on synovial fluid obtained from 38 patients with RA and 15 patients with OA. QUDA was identified and quantified using the gas chromatography-mass spectrometry (GC-MS) method. In vitro experiments were conducted on rabbit synoviocyte cell line HIG-82.

RESULTS

Presence of QUDA was detected in all 53 samples of synovial fluid. The concentration of QUDA in synovial fluid obtained from patients with RA was 28.6 ± 14.9 pmol/ml, which was lower in comparison with OA 42.3 ± 10.0 pmol/ml. QUDA content positively correlated with the number of tender joints and negatively with the total cell counts determined in synovial fluid of RA patients. It did not correlate with KYNA content. QUDA reduced both proliferation and motility of synoviocytes in a dose-dependent manner. The enhancement of antiproliferative action of QUDA by KYNA was evidenced.

CONCLUSIONS

Data show a local deficit of QUDA in RA patients and suggest its potential role as an endogenous substance controlling synoviocyte viability.

Evaluation of anticancer activity of water and juice extracts of young Hordeum vulgare in human cancer cell lines HT-29 and A549

Introduction and objective. Barley (Hordeum vulgare L.) is known as a rich source of different bioactive compounds. At present, considerable attention of researchers is focused on young barley grass. It can be a good source of dietary minerals, vitamins, carbohydrates, amino acids, phenolic compounds and proteins. It is possible that the composition of chemical ingredients beneficial for health may induce an anticancer potential of young barley in human colon adenocarcinoma (HT-29) and human lung adenocarcinoma (A549) cell lines. Materials and method. Hordeum vulgare water extract (HWE) and Hordeum vulgare juice extract (HJE) were prepared. Cell proliferation and viability were examined with the use of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and NR (neutral red) methods. Induction of necrosis was assessed by propidium iodide/Hoechst staining. Progress of the cell cycle involved in cell proliferation, apoptosis, and regulation of transcription was estimated using flow cytometry analysis. Additionally, the capability of free radical scavenging was evaluated with the DPPH assay. Results. The study revealed that extracts inhibited the proliferation of cancer cells. The NR study confirmed the low cytotoxic activity of the tested extracts to normal human colon epithelial cells (CCD 841 CoTr) and human skin fibroblasts (HSF). Furthermore, a dose-dependent cytotoxicity against HT-29 cells, but not A549 cells, has been reported. The free radical scavenging activity was observed in the case of the HWE but not the HJE. Conclusions. The obtained results indicate a cancer chemopreventive potential of young barley as a safe dietary agent in colon carcinoma.

Fomitopsis betulina (formerly Piptoporus betulinus): the Iceman's polypore fungus with modern biotechnological potential

Higher Basidiomycota have been used in natural medicine throughout the world for centuries. One of such fungi is Fomitopsis betulina (formerly Piptoporus betulinus), which causes brown rot of birch wood. Annual white to brownish fruiting bodies of the species can be found on trees in the northern hemisphere but F. betulina can also be cultured as a mycelium and fruiting body. The fungus has a long tradition of being applied in folk medicine as an antimicrobial, anticancer, and anti-inflammatory agent. Probably due to the curative properties, pieces of its fruiting body were carried by Ötzi the Iceman. Modern research confirms the health-promoting benefits of F. betulina. Pharmacological studies have provided evidence supporting the antibacterial, anti-parasitic, antiviral, anti-inflammatory, anticancer, neuroprotective, and immunomodulating activities of F. betulina preparations. Biologically active compounds such as triterpenoids have been isolated. The mushroom is also a reservoir of valuable enzymes and other substances such as cell wall (1→3)-α-D-glucan which can be used for induction of microbial enzymes degrading cariogenic dental biofilm. In conclusion, F. betulina can be considered as a promising source for the development of new products for healthcare and other biotechnological uses.

Temozolomide and sorafenib as programmed cell death inducers of human glioma cells

BACKGROUND

Gliomas are aggressive brain tumors with very high resistance to chemotherapy. Therefore, the aim of the present study was to investigate the effectiveness of sorafenib and Temozolomide in elimination of human glioma cells through apoptosis and autophagy.

METHODS

MOGGCCM (anaplastic astrocytoma) and T98G (glioblastoma multiforme) cell lines incubated with sorafenib and/or Temozolomide were used in the experiments. Cell morphology (ER stress, apoptosis, autophagy, and necrosis) was analyzed microscopically while apoptosis and mitochondrial membrane potential were assessed with flow cytometry. Beclin1, LC3, p62, Hsp27, and Hsp72 levels were analyzed by immunoblotting. The activity of caspase 3, 8, and 9 was evaluated fluorometrically. Expression of Hsps was blocked by transfection with specific siRNA.

RESULTS

In MOGGCCM cells, Temozolomide most frequently induced autophagy, which was accompanied by decreased p62 and increased beclin1 and LC3II levels. Sorafenib initiated mainly apoptosis. Additional incubation with Temozolomide, synergistically potentiated the pro-apoptotic properties of sorafenib, but it was mediated in a caspase-independent way. In T98G cells, the effect of the analyzed drugs on programmed cell death induction was different from that in MOGGCCM cells. Sorafenib induced autophagy, while Temozolomide initiated mainly apoptosis. After simultaneous drug application, apoptosis dominated, suggesting synergistic action of both drugs. Inhibition of Hsp27 and Hsp72 expression increased the sensitivity of both cell lines to ER stress and, to a lesser extent, to induction of apoptosis, but not autophagy.

CONCLUSIONS

Sorafenib and Temozolomide applied in combination are potent apoptosis inducers in T98G and MOGGCCM cells. ER stress precedes the elimination. Blocking of Hsp expression has a greater impact on ER stress rather than apoptosis induction.

Cultivation and utility of Piptoporus betulinus fruiting bodies as a source of anticancer agents

Piptoporus betulinus is a wood-rotting basidiomycete used in medicine and biotechnology. However, to date, no indoor method for cultivation of this mushroom fruiting bodies has been developed. Here we present the first report of successful production of P. betulinus mature fruiting bodies in artificial conditions. Four P. betulinus strains were isolated from natural habitats and their mycelia were inoculated into birch sawdust substrate supplemented with organic additives. All the strains effectively colonized the medium but only one of them produced fruiting bodies. Moisture and organic supplementation of the substrate significantly determined the fruiting process. The biological efficiency of the P. betulinus PB01 strain cultivated on optimal substrate (moisture and organic substance content of 55 and 65 and 25 or 35 %, respectively) ranged from 12 to 16 %. The mature fruiting bodies reached weight in the range from 50 to 120 g. Anticancer properties of water and ethanol extracts isolated from both cultured and nature-derived fruiting bodies of P. betulinus were examined in human colon adenocarcinoma, human lung carcinoma and human breast cancer cell lines. The studies revealed antiproliferative and antimigrative properties of all the investigated extracts. Nevertheless the most pronounced effects demonstrated the ethanol extracts, obtained from fruiting bodies of cultured P. betulinus. Summarizing, our studies proved that P. betulinus can be induced to fruit in indoor artificial culture and the cultured fruiting bodies can be used as a source of potential anticancer agents. In this respect, they are at least as valuable as those sourced from nature.

A New Method for the Isolation of Ergosterol and Peroxyergosterol as Active Compounds of Hygrophoropsis aurantiaca and in Vitro Antiproliferative Activity of Isolated Ergosterol Peroxide

In the present study, ergosterol peroxide and ergosterol were isolated for the first time from fresh fruit bodies of Hygrophoropsis aurantiaca (False Chanterelle). The substances were characterized mainly by spectroscopic methods (¹H-NMR, ¹³C-NMR, DEPT-45, DEPT-90, DEPT-135, 2D-NMR). In our study, a new specific thin layer chromatographic method was developed for determination of ergosterol and ergosterol peroxide in H.aurantiaca extract. The method is based on the separation of n-hexane extract on silica gel (Silica Gel G) TLC plates using the optimized solvent system toluene/ethyl acetate (3:1; v/v). The main advantages of the developed method are the simplicity of operation and the low cost. The in vitro study results revealed the antiproliferative properties of ergosterol peroxide against LS180 human colon cancer cells. The described effect was attributed both to altered mitochondrial activity and decreased DNA synthesis. Additionally, in the same concentration range the investigated compound was not toxic to CCD 841 CoTr human colon epithelial cells. The present study suggests that fruit bodies of H. aurantiaca have great potential for producing substances and extracts with potential applications in medicine.

Kynurenic Acid Induces Impairment of Oligodendrocyte Viability: On the Role of Glutamatergic Mechanisms

Kynurenic acid (KYNA) is an end stage product of tryptophan metabolism with a variety of functions in the human body, both in the central nervous system (CNS) and in other organs. Although its activity in the human brain has been widely studied and effects on neural cells were emphasized, the effect of KYNA on oligodendroglial cells remains unknown. Present study aims at describing the activity of high concentration of KYNA in OLN-93 cells. The inhibition of OLN-93 oligodendrocytes viability by KYNA in a medium with reduced serum concentration has been demonstrated. Although decreased metabolic activity of KYNA treated OLN-93 cells was shown, the cells proliferation was not altered. KYNA treatment did not alter morphology as well as expression level of cell cycle and proliferation regulating proteins. Furthermore, glutamate receptor antagonists and agonists did not alter the inhibitory effect of KYNA on viability of OLN-93 oligodendrocytes. This study contributes to the elucidation of effects of KYNA on oligodendrocytes in vitro, yet further analyses are necessary to explain the mechanisms behind the damage and loss of myelin sheaths.

Boletus edulis ribonucleic acid – a potent apoptosis inducer in human colon adenocarcinoma cells

Despite the large popularity of the Boletus edulis mushroom, little is known about its influence on human health and the possibilities of its therapeutic use.

Anticancer effect of ethanol Lycium barbarum (Goji berry) extract on human breast cancer T47D cell line

The anticancer activity of ethanol extract isolated from Goji berry (EEGB) on T47D human breast cancer cell line has been reported. Cell viability and cell proliferation were examined with the use of BrdU, MTT and NR methods. Induction of apoptosis was assessed by propidium iodide and Hoechst 33342 staining. Expression of genes involved in cell proliferation, apoptosis, cell cycle control and regulation of transcription was estimated using Western blotting analysis. EEGB inhibited the proliferation of breast cancer cells in a time-, and dose-dependent manner. The study confirmed the lack of EEGB cytotoxic activity to normal human skin fibroblasts. Western blot analysis demonstrated an increase in pro-apoptotic and a decrease in anti-apoptotic proteins' expression in cells treated with the extract. Anticancer activity and lack of toxicity against normal cells indicate a chemopreventive potential of Goji berries in breast cancer treatment.

Synthesis, characterization, and pharmacological evaluation of novel azolo- and azinothiazinones containing 2,4-dihydroxyphenyl substituent as anticancer agents

ABSTRACT

We reported the synthesis and characterization of a series of azolo- and azino[1,3]thiazinones containing the 2,4-dihydroxyphenyl substituent. The compounds were prepared by a new one-step reaction of aryl-modified sulfinylbis[(2,4-dihydroxyphenyl)methanethione]s and the corresponding aminoazolo(azino)carboxamides. Their chemical structures were confirmed by IR, NMR: 1H, 13C, HSQC, and EI-MS spectral data. The compounds inhibited proliferation and viability of lung cancer A549, colon cancer HT-29, and glioma C6 cells in a structure- and concentration-dependent manner. The activity of some analogues was below 10 μmol dm-3 (IC50). Glioma C6 cells were the most sensitive to tested compounds. Generally, the derivatives were not toxic for the skin fibroblast HSF culture. Moreover, some of them exerted a protective effect on the treated normal cells. Evaluation of compound properties in silico showed that they possess significant drug-like characteristics and most of them display a low toxicity.

GRAPHICAL ABSTRACT

Cytotoxicity of monensin, narasin and salinomycin and their interaction with silybin in HepG2, LMH and L6 cell cultures

The cytotoxic effect of monensin, narasin and salinomycin followed by their co-action with silybin in the cell line cultures of human hepatoma (HepG2), chicken hepatoma (LMH) or rat myoblasts (L6) have been investigated. The effective concentration of the studied ionophoric polyethers has been assessed within two biochemical endpoints: mitochondrial activity (MTT assay) and membrane integrity (LDH assay) after 24h incubation of each compound and farther, the cytotoxicity influenced in course of their interaction with silybin was determined. The most affected endpoints were found for inhibition of mitochondrial activity of the hepatoma cell lines and their viability depended on concentration of the ionophoric polyether, as well as on the cell line tested. The rat myoblasts were more sensitive target for cellular membrane damage when compared to inhibition of mitochondrial activity. An interaction between the ionophoric polyethers and silybin resulted a considerable cytotoxicity decrease within all studied cell lines; the combination index (CI) showed differences of interaction mode and dependence on cell culture, concentration of silybin, as well as the assay used. The obtained results are of interest in respect to recent findings on applicability of salinomycin and monensin for human therapy.

Chlorpyrifos and cypermethrin induce apoptosis in human neuroblastoma cell line SH-SY5Y

Our previous in vivo studies showed that chlorpyrifos (CPF) and cypermethrin (CM) in a mixture dermally administered, strongly inhibited cholinesterase activity in plasma and the brain and were very toxic to the rat central nervous system. In this work, the mechanisms of neurotoxicity have not been elucidated. We used human undifferentiated SH-SY5Y cells to study mechanisms of pesticide-induced neuronal cell death. It was found that chlorpyrifos (CPF) and its mixture with cypermethrin (CPF+CM) induced cell death of SH-SY5Y cells in a dose- and time-dependent manner, as shown by MTT assays. Pesticide-induced SH-SY5Y cell death was characterized by concentration-dependent down-regulation of Bcl-2 and Bcl-xL as well as an increase in the caspase 3 activation. Pan-caspase inhibitor Q-VD-OPh produced a slight but significant reversal effect of pesticide-induced toxicity indicating that the major caspase pathways are not integral to CPF- and CPF+CM-induced cell death. Furthermore, signal transduction inhibitors PD98059, SL-327, SB202190, SP600125 and mecamylamine failed to attenuate pesticides effect. Atropine exhibited minimal ability to reverse toxicity. Finally, it was shown that inhibition of TNF-α by pomalidomide attenuated CPF-/CPF+CM-induced apoptosis. Overall, our data suggest that FAS/TNF signalling pathways may participate in CPF and CPF+CM toxicity.

The effect of quercetin and imperatorin on programmed cell death induction in T98G cells in vitro

BACKGROUND

High expression of HSP27 and HSP72 in glioma cells has been closely associated with chemoresistance and decreased sensitivity to programmed cell death induction. Therefore, it is important to devise therapies that effectively target invasive cancer cells by inducing cell death. The aim of our study was to assess the effect of quercetin and imperatorin applied separately and in combinations on the apoptosis and autophagy induction in human T98G cells cultured in vitro.

METHODS

Cell death induction was analyzed by the staining method. The Western blotting technique and fluorimetric measurements of activity were used to assess the expression of marker proteins of apoptosis and autophagy. The specific siRNA transfected method was used for blocking of the expression of HSP27 and HSP72 genes.

RESULTS

The experiments revealed the highest percentage of apoptotic cells after using a 50?M concentration of both compounds. Simultaneous quercetin and imperatorin administration induced apoptosis more effectively than incubation with single drugs. These results were accompanied with decreased HSP27 and HSP72 expression, and a high level of caspase-3 and caspase-9 activity. Autophagy was not observed. Additional experiments were performed on a cell line with blocked Hsp27 and Hsp72 expression and significant increase the sensitivity to apoptosis induction upon quercetin and imperatorin treatment was noticed.

CONCLUSIONS

The present study indicates that quercetin and imperatorin are potent apoptosis inducers, especially when they act synergistically, which may be a promising combination useful in glioma therapy. Our results also demonstrated that blocking the HSP27 and HSP72 gene expression might serve as a therapeutic target for the human brain cancer.

Kynurenic acid inhibits proliferation and migration of human glioblastoma T98G cells

BACKGROUND

Kynurenic acid (KYNA), tryptophan metabolite synthesized in the kynurenine pathway, is an endogenous antagonist of α-7 nicotinic receptor and all ionotropic glutamate receptors: N-methyl-D-aspartate (NMDA) receptor, α-amino-3-hydroxy-5-methyl-4-isoxasole propionate (AMPA) receptor and kainate receptor. The antiproliferative activity of KYNA toward colon and renal cancer cells has recently been discovered. The aim of the study was to verify whether human Glioblastoma tumors contain KYNA and if KYNA influences glioma cell proliferation and migration.

METHODS

KYNA content in Glioblastoma tumor samples was determined using HPLC. Proliferation of human glioblastoma T98G cells was measured by means of MTT and BrdU assays. Wound assay was used to evaluate the effect of KYNA on cancer cell migration.

RESULTS

KYNA was detected in all tested Glioblastoma tumor samples (100.3 ± 17.6 pmol/g wet weight). In a series of experiments the antiproliferative activity of KYNA against T98G cells was revealed (IC(50) = 1.3 mM). Moreover, KYNA reversed the stimulatory effect of glutamate on glioma cell proliferation and enhanced antiproliferative effect of glutamate receptor antagonists MK801 and GYKI 52466. Next, KYNA at concentrations much lower than those needed to reduce cell proliferation elicited a prominent inhibitory effect on glioma cell motility. Moreover, co-incubation of temozolomide, a drug commonly used in antiglioblastoma therapy, with KYNA gave a superior effect than each of the substances applied alone.

CONCLUSIONS

We demonstrate the antiproliferative and antimigrative potential of KYNA against glioma cells in vitro.

Quercetin and sorafenib as a novel and effective couple in programmed cell death induction in human gliomas

The aim of the present study was to investigate the effect of sorafenib and quercetin on the induction of apoptosis and autophagy in human anaplastic astrocytoma (MOGGCCM) and glioblastoma multiforme (T98G) cell lines. In MOGGCCM cells, sorafenib initiated mainly apoptosis, mediated by the mitochondrial pathway with mitochondrial membrane permeabilization, cytochrome c release to the cytoplasm, and activation of caspase 9 and 3. Additional incubation with quercetin potentiated the pro-apoptotic properties of sorafenib. In T98G cells, autophagy was observed most frequently after the sorafenib treatment. It was accompanied by increased beclin 1 and LC3II expression. Administration of quercetin after the sorafenib treatment resulted in an increased number of autophagic cells. After simultaneous drug application, the level of autophagy was lower in favour of apoptosis. Inhibition of heat shock proteins expression by specific small interfering RNA significantly increased the sensitivity of both the cell lines to induction of apoptosis, but not autophagy. We demonstrated for the first time that sorafenib and quercetin are very effective programmed cell death inducers in T98G and MOGGCCM cells, especially in cells with blocked expression of heat shock proteins.

Apoptosis induction in human glioblastoma multiforme T98G cells upon temozolomide and quercetin treatment

Glioblastoma multiforme is the most aggressive primary brain tumour. At the cellular and molecular levels, several mechanisms responsible for apoptosis or autophagy induction are blocked. Identification of molecular targets stimulating cells to initiate programmed cell death should be performed for therapeutic purposes. A promising solution is the combination of temozolomide and quercetin. The aim of our study was to evaluate the effect of both drugs, applied alone and in combinations, on apoptosis and autophagy induction in human glioblastoma multiforme T98G cells. Our results clearly indicate that quercetin and temozolomide induce apoptosis very significantly, having no effect on autophagy induction. At the molecular level, it was correlated with caspase 3 and 9 activation, cytochrome c release from the mitochondrium and a decrease in the mitochondrial membrane potential. Both drugs are also potent Hsp27 and Hsp72 inhibitors. This suggests that the apoptotic signal goes through an internal pathway. Increased expression of caspase 12 and the presence of several granules in the cytoplasm after temozolomide treatment with or without quercetin preceding appearance of apoptosis may suggest that apoptosis is initiated by ER stress. Additionally, it was accompanied by changes in the nuclear morphology from circular to 'croissant like'.