Combretastatin A-4 suppresses the invasive and metastatic behavior of glioma cells and induces apoptosis in them: in-vitro study

The most common primary brain malignancy, glioblastoma multiforme, is tremendously resistant to conventional treatments due to its potency for metastasis to surrounding brain tissue. Temozolomide is a chemotherapeutic agent that currently is administrated during the treatment procedure. Studies have attempted to investigate new agents with higher effectiveness and fewer side effects. Combretastatin A-4 (CA-4), a natural compound derived from Combretum caffrum, has been recently considered for its potent antitumor activities in a wide variety of preclinical solid tumor models. Our findings have shown that CA-4 exerts potent anti-proliferative and apoptotic effects on glioma cells, and ROS generation may be involved in these cellular events. CA-4 has imposed G2 arrest in U-87 cells. We also observed that CA-4 significantly reduced the migration and invasion capability of U-87 cells. Furthermore, the gene expression and enzyme activity of MMP-2 and MMP-9 were significantly inhibited in the presence of CA-4. We also observed a considerable decrease in PI3K and Akt protein expression following treatment with CA-4. In conclusion, our findings showed significant apoptogenic and anti-metastatic effects of CA-4 on glioma cells and also suggested that the PI3K/Akt/MMP-2/-9 and also ROS pathway might play roles in these cellular events.

Pegylated liposomal encapsulation improves the antitumor efficacy of combretastatin A4 in murine 4T1 triple-negative breast cancer model

Combretastatin A4 (CA4), a vascular disrupting agent has been recently proposed as an anticancer agent. However, its low water solubility and low bioavailability limited its clinical efficacy. Overcomingthis issue requires developing new delivery strategies to enhance its anticancer effects. Here, we prepared various PEGylated liposomal formulations containing CA4 composed of different molar ratios of HSPC/DSPE-mPEG₂₀₀₀/Cholesterol/CA4 (F1: 80:5:10:5; F2: 75:5:15:5; F3: 70:5:20:5; F4: 60:5:30:5 and F5: 50:5:40:5) by the thin-film hydration method plus sonication and extrusion. All formulations had a particle diameter of 100-150 nm, a monomodal distribution with low polydispersity index and a negative zeta potential. Among the formulations only F1, F2, and F3 showed a high CA4 encapsulation efficiency; so their anticancer effects on triple-negative breast cancer (TNBC) were investigated in vitro and in vivo. The release study showed that F3 liposomes had significantly lower CA4 release compared to the F1 and F2 liposomes in different pH of 5.5, 6.5, and 7.4. We found that, CA4-loaded liposomes effectively inhibited both proliferation and migration of 4T1 and MDA-MB-231 TNBC cell lines by inducing cell cycle arrest at the G2/M phase and decreasing MMP-2 and MMP-9 expression and activity. In vivo studies revealed that F3 liposomes were highly accumulated at the tumor site and more effectively delayed tumor growth andprolonged the overall survival than other groups in 4T1 breast tumor-bearing mice. Taken together, encapsulation of CA4 in PEGylated F3 liposomes enhances its anti-tumor activity and may be serve as a promising approach for TNBC treatment and merits further investigation.

Protective Role of Natural Products in Glioblastoma Multiforme: A Focus on Nitric Oxide Pathway

In spite of therapeutic modalities such as surgical resection, chemotherapy, and radiotherapy, Glioblastoma Multiforme (GBM) remains an incurable fatal disease. This necessitates further therapeutic options that could enhance the efficacy of existing modalities. Nitric Oxide (NO), a short-lived small molecule, has been revealed to play a crucial role in the pathophysiology of GBM. Several studies have demonstrated that NO is involved in apoptosis, metastasis, cellular proliferation, angiogenesis, invasion, and many other processes implicated in GBM pathobiology. Herein, we elaborate on the role of NO as a therapeutic target in GBM and discuss some natural products affecting the NO signaling pathway.

Cytotoxic Effects of Ferula Latisecta on Human Glioma U87 Cells

Glioblastoma multiforme (GBM) is the fatal type of astrocytic tumors with a survival rate of 12 months. The present study, for the first time, evaluated the cytotoxic impacts of Ferula latisecta (F. latisecta) hydroalcoholic extract on U87 GBM cell line. The MTT assay measured the cellular toxicity following 24- and 48 h treatment with various doses of F. latisecta (0-800 μg/mL). Apoptosis was evaluated by an Annexin V/propidium iodide (PI) staining 24 h after treatment by F. latisecta. Moreover, to determine the cellular metastasis of U87 cells, we used a gelatin zymography assay (matrix metalloproteinase [MMP]-2/-9 enzymatic activity). The outcomes showed that F. latisecta mitigated the viability of U87 cells in a concentration- and time-dependent manner with IC₅₀ values of 145.3 and 192.3 μg/mL obtained for 24- and 48 h treatments, respectively. F. latisecta induced apoptosis in a concentration-dependent manner after 24 h. Also, MMP-9 activity was significantly decreased following 24 h after treatment concentration-dependently with no change in MMP-2 enzymatic activity. This study showed that F. latisecta induced cytotoxicity and apoptosis, and mitigated metastasis of U87 GBM cells. Hence, F. latisecta could be beneficial as a promising natural herb against GBM after further studies.

Role of AKT and mTOR signaling pathways in the induction of epithelial-mesenchymal transition (EMT) process

Epithelial-mesenchymal transition (EMT) is a critical process in the development of many tissues and organs in multicellular organisms that its important role in the pathogenesis of metastasis and tumor cell migration has been firmly established. Decreased adhesive capacity, cytoskeletal reorganization, and increased mobility are hallmarks of the EMT. Several molecular mechanisms promote EMT, Including regulation of the levels of specific cell-surface proteins, ECM-degrading enzymes, and altering the expression of certain transcription factors and microRNAs. EMT process is modulated through multiple signaling pathways including the AKT/mTOR pathway. AKT is a key component in numerous processes which was recently shown to regulate the EMT through suppression of the expression of E-cadherin via EMT transcription factors. On the other hand, mTOR complexes can also regulate the EMT through the regulation of cell's actin cytoskeleton by altering the PKC phosphorylation state and direct phosphorylation and activation of Akt. Here we review the effect of AKT and mTOR on EMT and consequently metastasis and cell motility.

Auraptene-induced cytotoxicity mechanisms in human malignant glioblastoma (U87) cells: role of reactive oxygen species (ROS)

Glioblastoma multiforme (GBM), like the devastating type of astrocytic tumors, is one of the most challenging cancers to treat owing to its aggressive nature. Auraptene, as a prenyloxy coumarin from citrus species, represents antioxidant and antitumor activities; however, the underlying antitumor mechanisms of auraptene against GBM remain unclear. The present study aimed to evaluate the cytotoxic and apoptogenic effects of auraptene, as a promising natural product, and the possible signaling pathways affected in human malignant GBM (U87) cells. Reactive oxygen species (ROS) production significantly decreased in the first 2, and 6 hours after treatment with auraptene however, ROS levels increased in other incubation times (8 and 24 hours), dramatically. N-acetyl-cysteine (NAC) markedly attenuated auraptene-induced ROS production, and consequently reversed auraptene-induced cytotoxicity in 8 and 24 hours after treatment, as well. Induction of apoptosis occurred in the first 24- and 48-hours concentration-dependently. The qRT-PCR showed an up-regulation in p21, CXCL3, and a down-regulation in Cyclin D1 genes expression. Western blot analysis confirmed the up-regulation of the Bax/Bcl-2 ratio protein levels concentration-dependently. Hence, this study collectively revealed that the increase in ROS level is at least one of the mechanisms associated with auraptene-induced GBM cell toxicity as well as the induction of apoptosis through Bax/Bcl-2 modulation and genes expression involved that contribute to the cytotoxicity of auraptene in U87 cells. So, auraptene might be utilized as a potential novel anti-GBM agent after further studies.

Cytotoxic effects of auraptene against a human malignant glioblastoma cell line

OBJECTIVE

Glioblastoma multiforme (GBM) is the deadliest type of primary brain tumors, and the survival of patients is estimated to be only about one year. This study, for the first time, investigated the cytotoxic effects of auraptene on U87 GBM cell line.

MATERIALS AND METHODS

The cellular toxicity was measured by the MTT assay following 24 and 48-hr treatment with different concentrations of auraptene (0-400μg/ml). Apoptosis was evaluated by sub-G1 peak in cell cycle analysis of propidium-iodide- stained nuclei. Moreover, to determine the Bax, Bcl-2, MCP-1, NF-κB, IL-1β, and p53 genes expression, we used real-time polymerase chain reaction (RT-PCR).

RESULTS

The results revealed that auraptene reduced the viability of U87 cells concentration- and time-dependently with IC₅₀ values of 108.9 and 79.17μg/ml obtained for 24 and 48-hr treatments, respectively. Also, sub-G1 population was significantly increased following 24 (p<0.05 and p<0.001) and 48 (p<0.001) hours of treatment. The quantitative real-time RT-PCR showed an up-regulation in Bax, NF-κB, IL-1β, and p53 but a down-regulation in MCP-1 and Bcl-2 genes expression.

CONCLUSION

This study showed that auraptene triggered apoptosis probably through Bax/Bcl-2 regulation, blocked cell cycle progression and inhibited proliferation in U87 GBM cells. Taken together, auraptene can be utilized as an effective natural medicine against GBM, after complementary studies.

In vivo and In vitro effects of ethanolic extract of Trigonella foenum-graecum L. seeds on proliferation, angiogenesis and tube formation of endothelial cells

The role of angiogenesis in tumor progression and metastasis formation has been well recognized. Recent studies have reported that Trigonella foenum-graecum L. (fenugreek) seed extracts have potential anticancer properties. The current study was planned to investigate the anti-angiogenic activity of hydroalcoholic extract of fenugreek (HAEF) in vitro and in vivo. Effect of HAEF (50-3000 µg/mL) and thalidomide (200-3000 µmol/L), as a positive control, on the viability of human umbilical vein endothelial cells (HUVECs) and 3T3 fibroblast cells was assessed by thiazolyl blue tetrazolium bromide (MTT) assay. Effect of HAEF on vessel-like tube formation by HUVECs was examined in the matrigel-based assay. Furthermore, the chick chorioallantoic membrane (CAM) was used as in vivo model to study the anti-angiogenic effect of HAEF. HAEF, similar to thalidomide, significantly inhibited the viability of HUVECs and 3T3 cells dose-dependently after 24 h. Moreover, both HAEF and thalidomide significantly reduced tube formation by HUVECs in cell culture condition. In CAM model, HAEF and thalidomide caused a significant decline in the number of neovascular points and in the amount of grades 1 and 2 vessels. These findings revealed that fenugreek has cytotoxic and anti-angiogenic effects in vitro and in vivo. Therefore, this medicinal plant can be subjected to further investigations as antitumor agents.

Therapeutic potency of mTOR signaling pharmacological inhibitors in the treatment of proinflammatory diseases, current status, and perspectives

Mammalian target of rapamycin (mTOR) signaling pathway controls cell energy metabolism. There is an interplay between mTOR and proinflammatory signaling pathways, supporting the role of the pathway in the pathogenesis of inflammatory diseases. Inhibition of mTOR signaling using specific pharmacological inhibitors could offer therapeutic promise in several inflammatory-associated diseases. In this review, we summarize recent findings on the regulatory effects of mTOR signaling on inflammation and the therapeutic potency of mTOR pharmacological inhibitors in the treatment of inflammatory diseases including cancer, neurodegenerative diseases, atherosclerosis, sepsis, and rheumatoid arthritis for a better understanding and hence a better management of these diseases.

Oesophageal cancer among the Turkomans of northeast Iran

A Caspian Littoral Cancer Registry survey in the early 1970s established northern Iran as one of the highest oesophageal cancer incidence regions of the world. To verify this, an oesophageal cancer survey was carried out between 1995 and 1997 in the Turkoman Plain at the southeastern corner of the Caspian Sea. Oesophageal balloon cytology screening was carried out on 4192 asymptomatic adults above age 30 years in one town and three adjoining villages with a total population of 20 392 people at risk. Oesophagoscopy was performed on 183 patients with abnormal cytological findings. The discovery of two asymptomatic small squamous cell cancers and one 'carcinoma- suspect' implied a prevalence ranging from 47.7 per 100 000 to 71.5 per 100 000. During a 1-year active surveillance, 14 patients were found with clinically advanced oesophageal squamous cell cancer, yielding age-standardized incidence rates of 144.09 per 100 000 for men and 48.82 per 100 000 for women. The very high frequency of oesophageal cancer reported for northern Iran 25 years ago stands confirmed. Differences in incidence rates, then and now, can be attributed to survey methods used and diagnostic criteria applied, but not to socioeconomic factors, which have remained relatively stable. Oesophageal balloon cytology is a practical method of mass screening for oesophageal cancer in Iran.