Temozolomide may induce cell cycle arrest by interacting with URG4/URGCP in SH-SY5Y neuroblastoma cells

The relationship between URG4 and clinicopathologic parameters and its effect on two-year survival in gastric carcinoma

AIM

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. The present study examined the relationship between Upregulated gene 4 (URG4) expression, an oncogene involved in the development of gastric carcinoma, and clinicopathologic parameters including Human epidermal growth factor receptor 2 (HER2) status. The study aimed to investigate the importance of URG4 as a prognostic factor for 2-year survival in GCs, which are usually in the advanced stage at the time of diagnosis and have a rapid course.

METHODS

In 61 patients with GC, URG4 expression results in paraffin blocks were compared with the patients' clinicopathologic, 2-year survival, and HER2 results.

RESULTS

Among the patients, 24 (39 %) had low URG4 scores (scores 0-4) and 37 (61 %) had high URG4 scores (scores 6-9). While the HER2 score was negative in 52 (85 %)patients, it was positive in 9 (15 %). URG4 expression values were significantly correlated with tumor (T) stage and lymphovascular invasion (LVI) (p < 0.005), whereas no significant correlation was determined between other pathological prognostic factors and HER2 status (p > 0.005). During the two-year period, 32 (52 %) patients survived and 29 (48 %) died. The mean duration of survival was 75.20 ± 35.22 weeks. A significant correlation was determined between URG4 values and survival and mortality results (p < 0.05).

CONCLUSION

We revealed a correlation (p < 0.005) between increased URG4 scores with increased T stage and LVI. We demonstrated an association between increased URG4 expression and survival time and mortality in patients with GC during the first two years of survival (p < 0.005) and URG4 and HER2 yielded similar results as prognostic factors in the survival of the patients URG4 is an essential oncogene in malignancies, especially in gastric GC, requiring further research and development in prognostic and therapeutic areas.

Cinnamophilin enhances temozolomide-induced cytotoxicity against malignant glioma: the roles of ROS and cell cycle arrest

Background

Temozolomide (TMZ) has been widely used to treat glioblastoma multiforme (GBM). However, many mechanisms are known to quickly adapt GBM cells to chemotherapy with TMZ, leading to drug resistance and expansion of tumor cell populations.

Methods

We subjected human glioblastoma cell lines and an animal model of glioblastoma xenografts with TMZ-based adjuvant treatments to evaluate the synergistic effect of cinnamophilin (CINN), a free radical scavenger.

Results

Our results showed that the combined treatment of CINN and TMZ potentiated the anticancer effect and apoptotic cell death in glioma cell lines and enhanced antitumor action in glioma xenografts. TMZ induced reactive oxygen species (ROS) burst and elevated G2 arrest in glioma cells. The CINN-suppressed ROS burst in TMZ-treated glioma cells might be associated with increased apoptosis, as indicated by the upregulation of TUNEL-positive glioma cells. CINN-pretreated glioma cells exhibited increased cyclin B expression and reduced phosphorylation of Cdk1, suggesting reduced G2 arrest in the combined treatment group. Moreover, CINN lowered the protein level of LC3, a hallmark of autophagy, in TMZ-treated cells.

Conclusions

These findings suggest that CINN may restore TMZ toxicity in glioma cancer by suppressing the ROS/G2 arrest pathway.

Identification of 2-Fluoropalmitic Acid as a Potential Therapeutic Agent Against Glioblastoma

BACKGROUND

Glioblastomas (GBMs) are aggressive malignant brain tumors. Although chemotherapy with temozolomide (TMZ) can extend patient survival, most patients eventually demonstrate resistance. Therefore, novel therapeutic agents that overcome TMZ chemoresistance are required to improve patient outcomes.

PURPOSE

Drug screening is an efficient method to find new therapeutic agents from existing drugs. In this study, we explored a novel anti-glioma agent by drug screening and analyzed its function with respect to GBM treatment for future clinical applications.

METHODS

Drug libraries containing 1,301 diverse chemical compounds were screened against two glioma stem cell (GSC) lines for drug candidate selection. The effect of selected agents on GSCs and glioma was estimated through viability, proliferation, sphere formation, and invasion assays. Combination therapy was performed to assess its ability to enhance TMZ cytotoxicity against GBM. To clarify the mechanism of action, we performed methylation-specific polymerase chain reaction, gelatin zymography, and western blot analysis.

RESULTS

The acyl-CoA synthetase inhibitor 2-fluoropalmitic acid (2-FPA) was selected as a candidate anti-glioma agent. 2-FPA suppressed the viability and stem-like phenotype of GSCs. It also inhibited proliferation and invasion of glioma cell lines. Combination therapy of 2-FPA with TMZ synergistically enhanced the efficacy of TMZ. 2-FPA suppressed the expression of phosphor-ERK, CD133, and SOX-2; reduced MMP-2 activity; and increased methylation of the MGMT promoter.

CONCLUSION

2-FPA was identified as a potential therapeutic agent against GBM. To extend these findings, physiological studies are required to examine the efficacy of 2-FPA against GBM in vivo.

Ferulic acid-mediated modulation of apoptotic signaling pathways in cancer

Ferulic acid (4-hydroxy-3-methoxycinnamic acid, FA), a hydroxycinnamic acid derived from various seeds, nuts, leaves, and fruits, exists in a free form as well as is covalently conjugated with polysaccharides, glycoproteins, polyamines, lignin, and hydroxy fatty acids of plant cell walls. It exhibits a variety of pharmacological effects, such as antioxidant, anti-inflammatory, vasodilatory, antithrombotic, antimicrobial, anti-allergic, antiviral, hepatoprotective, and anticancer activities. FA induces the expression of cell cycle-related proteins, such as p53 and p21, and reduces cyclin D1 and cyclin E levels. Moreover, FA triggers apoptosis and autophagic cell death depending on intracellular reactive oxygen species production in various cancer cell lines. The potential apoptotic action of FA is mediated by altered expression of procaspase-3, procaspase-8, procaspase-9, poly (ADP ribose) polymerase, Bcl-2, and Bax. It blocks the activation of both the canonical Smad and noncanonical extracellular-signal-regulated kinase/Akt (protein kinase B) pathways in various cancer cells. However, due to low solubility and permeability, its availability to biological systems is limited. Therefore, encapsulation of FA into chitosan tripolyphosphate nanoparticles may enhance its cytocompatibility, solubility, and anticancer potential. The nanohybrids of FA and double layered hydroxide exhibit cellular delivery properties of intercalated molecules on cancer cell lines. This chapter summarizes the anticancer efficacy of FA with an emphasis on the role of apoptosis, and underlying molecular mechanisms involving various signaling pathways in tumor cells.

Role of NKCC1 Activity in Glioma K+ Homeostasis and Cell Growth: New Insights With the Bumetanide-Derivative STS66

Introduction: Na⁺-K⁺-2Cl⁻ cotransporter isoform 1 (NKCC1) is important in regulating intracellular K⁺ and Cl⁻ homeostasis and cell volume. In this study, we investigated a role of NKCC1 in regulating glioma K⁺ influx and proliferation in response to apoptosis inducing chemotherapeutic drug temozolomide (TMZ). The efficacy of a new bumetanide (BMT)-derivative NKCC1 inhibitor STS66 [3-(butylamino)-2-phenoxy-5-[(2, 2, 2-trifluoroethylamino) methyl] benzenesulfonamide] in blocking NKCC1 activity was compared with well-established NKCC1 inhibitor BMT.

Methods: NKCC1 activity in cultured mouse GL26 and SB28-GFP glioma cells was measured by Rb⁺ (K⁺) influx. The WNK1-SPAK/OSR1-NKCC1 signaling and AKT/ERK-mTOR signaling protein expression and activation were assessed by immunoblotting. Cell growth was determined by bromodeoxyuridine (BrdU) incorporation assay, MTT proliferation assay, and cell cycle analysis. Impact of STS66 and BMT on cell Rb⁺ influx and growth was measured in glioma cells treated with or without TMZ.

Results: Rb⁺ influx assay showed that 10 μM BMT markedly decreased the total Rb⁺ influx and no additional inhibition detected at >10 μM BMT. In contrast, the maximum effects of STS66 on Rb⁺ influx inhibition were at 40–60 μM. Both BMT and STS66 reduced TMZ-mediated NKCC1 activation and protein upregulation. Glioma cell growth can be reduced by STS66. The most robust inhibition of glioma growth, cell cycle, and AKT/ERK signaling was achieved by the TMZ + STS66 treatment.

Conclusion: The new BMT-derivative NKCC1 inhibitor STS66 is more effective than BMT in reducing glioma cell growth in part by inhibiting NKCC1-mediated K⁺ influx. TMZ + STS66 combination treatment reduces glioma cell growth via inhibiting cell cycle and AKT-ERK signaling.

URG4 mediates cell proliferation and cell cycle in osteosarcoma via GSK3β/β-catenin/cyclin D1 signaling pathway

BACKGROUND

Osteosarcoma is one of the most common malignant bone tumors with the annual global incidence of approximately four per million. Upregulated gene 4 (URG4) expression in the osteosarcoma tissue is closely associated with recurrence, metastasis, and poor prognosis of osteosarcoma. However, the biological function and underlying mechanisms of URG4 in osteosarcoma have not been elucidated. This study aimed to explore the expression and underlying mechanism of URG4 in osteosarcoma.

METHODS

The expression level of URG4 in osteosarcoma and normal tissues was compared using immunohistochemistry (IHC). PCR and western blotting (WB) techniques are used to detect URG4 mRNA and protein levels. Wound healing and Transwell analysis to assess the effect of URG4 on osteosarcoma cell migration and invasion. Cell Counting Kit-8 assay and colony proliferation assay were performed to evaluate the effects of silencing URG4 on the inhibition of cell proliferation. The cell cycle distribution was detected by flow cytometry, and a xenograft mouse model was used to verify the function of URG4 in vivo.

RESULTS

URG4 was found to be highly expressed in osteosarcoma tissues and cells, and its high expression was correlated with advanced Enneking stage, large tumor size, and tumor metastasis in osteosarcoma patients. The proliferation in osteosarcoma cell lines and cell cycle in the S phase was suppressed when siRNA was used to downregulate URG4. URG4 promoted cell proliferation and tumorigenesis in vitro and in vivo. WB verified that URG4 promotes cell proliferation in osteosarcoma via pGSK3β/β-catenin/cyclinD1 signaling.

CONCLUSION

URG4, which is high-expressed in osteosarcoma, promotes cell cycle progression via GSK3β/β-catenin/cyclin D1 signaling pathway and may be a novel biomarker and potential target for the treatment of osteosarcoma.

Selenium enhances TRPA1 channel-mediated activity of temozolomide in SH-SY5Y neuroblastoma cells

PURPOSE

Neuroblastoma is a malignant solid tumor that originates from the sympathetic nervous system in early childhood. Temozolomide is used for treatment in high-risk groups with low treatment response of neuroblastomas. TRPA1 channels in neuroblastoma cells are calcium permeable channels that can be activated by reactive oxygen species (ROT). In this study, we aimed to evaluate the level of activity of temozolomide and selenium in neuroblastoma cells via TRPA1 channels.

METHOD

Seven main groups were formed using SH-SY5Y neuroblastoma cells. The control was divided into temozolomide (TMZ) (100 μM, 24 h), TMZ+SEL+AP18, SEL (sodium selenite, 100 μM, 24 h), and SEL+AP18 groups. Intergroup calcium signaling, intracellular reactive oxygen species, caspase-3 and caspase-9, and mitochondrial depolarization analyses were performed by channel activation with TRPA1 agonist cinnamaldehyde in all groups.

RESULTS

Cytosolic calcium concentration, apoptosis, caspase-3 and caspase-9 activation, mitochondrial membrane depolarization, and ROT levels were higher in TMZ (p < 0.001), TMZ+SEL (p < 0.001), and SEL (p < 0.05) groups than the control group. TRPA1 was lower in TTMZ+AP18, TMZ+SEL+AP18, and SEL+AP18 groups with channel blockers than respectively TMZ, TMZ+SEL, and SEL groups without channel blockers (p < 0.05).

CONCLUSION

The use of selenium with temozolomide increased the apoptotic efficacy of temozolomide via TRPA1 channels on tumor cells.

The synergistic effect of DZ‑NEP, panobinostat and temozolomide reduces clonogenicity and induces apoptosis in glioblastoma cells

Current treatment against glioblastoma consists of surgical resection followed by temozolomide, with or without combined radiotherapy. Glioblastoma frequently acquires resistance to chemotherapy and/or radiotherapy. Novel therapeutic approaches are thus required. The inhibition of enhancer of zeste homolog 2 (EZH2; a histone methylase) and histone deacetylases (HDACs) are possible epigenetic treatments. Temozolomide, 3‑deazaneplanocin A (DZ‑Nep; an EZH2 inhibitor) and panobinostat (an HDAC inhibitor) were tested in regular and temozolomide‑resistant glioblastoma cells to confirm whether the compounds could behave in a synergistic, additive or antagonistic manner. A total of six commercial cell lines, two temozolomide‑induced resistant cell lines and two primary cultures derived from glioblastoma samples were used. Cell lines were exposed to single treatments of the drugs in addition to all possible two‑ and three‑drug combinations. Colony formation assays, synergistic assays and reverse transcription‑quantitative PCR analysis of apoptosis‑associated genes were performed. The highest synergistic combination was DZ‑Nep + panobinostat. Triple treatment was also synergistic. Reduced clonogenicity and increased apoptosis were both induced. It was concluded that the therapeutic potential of the combination of these three drugs in glioblastoma was evident and should be further explored.

Combinatorial Use of DNA Ligase Inhibitor L189 and Temozolomide Potentiates Cell Growth Arrest in HeLa

Introduction:

The issues of carcinoma drug resistance to alkylating agents such as Temozolomide (TMZ) are considered as a major concern in therapeutics. The potential ways to achieve better cancer cell growth arrest and cytotoxicity have been suggested including the combinatorial use of DNA repair protein inhibitors and genotoxic drug TMZ. Here, authors assess the ability of DNA ligase inhibitor (L189) to modulate TMZ mediated HeLa cell growth arrest and cytotoxicity.

Materials and Methods:

Here, authors have employed Trypan blue dye exclusion and propidium iodide (PI) using FACS to determine HeLa cell viability after exposure to TMZ with or without L189 inhibitor. Additionally, authors show the DNA ligase III protein level using ELISA and fluorescent microscopy to support the observed effects of combinatorial use of TMZ and L189.

Results:

In this paper, data indicate that the addition of L189 produced appreciable decrease in the growth of HeLa cells. However, combined treatment of L189 and TMZ showed enhanced TMZinduced HeLa growth arrest possibly in G2/M cell cycle phase without employing cell death mechanisms.

Conclusions:

These results underscore the combinatorial treatment using TMZ and L189 to bring desirable cancer cell growth arrest and future molecular study to dissect out the participating pathways.

Targeted and Synergic Glioblastoma Treatment: Multifunctional Nanoparticles Delivering Verteporfin as Adjuvant Therapy for Temozolomide Chemotherapy

Despite advances in cancer therapies, glioblastoma multiforme treatment remains inefficient due to the brain-blood barrier (BBB) inhibitory activity and to the low temozolomide (TMZ) chemotherapeutic selectivity. To improve therapeutic outcomes, in this work we propose two strategies, (i) photodynamic therapy (PDT) as adjuvant treatment and (ii) engineering of multifunctional theranostic/targeted nanoparticles ( m-NPs) that integrate biotin as a targeting moiety with rhodamine-B as a theranostic agent in pluronic P85/F127 copolymers. These smart m-NPs can surmount the BBB and coencapsulate multiple cargoes under optimized conditions. Overall, the present study conducts a rational m-NP design, characterization, and optimizes the formulation conditions. Confocal microscopy studies on T98-G, U87-MG, and U343 glioblastoma cells and on NIH-3T3 normal fibroblast cells show that the m-NPs and the encapsulated drugs are selectively taken up by tumor cells presenting a broad intracellular distribution. The formulations display no toxicity in the absence of light and are not toxic to healthy cells, but they exert a robust synergic action in cancer cells in the case of concomitant PDT/TMZ treatment, especially at low TMZ concentrations and higher light doses, as demonstrated by nonlinear dose-effect curves based on the Chou-Talalay method. The results evidenced different mechanisms of action related to the disjoint cell cycle phases at the optimal PDT/TMZ ratio. This effect favors synergism between the PDT and the chemotherapy with TMZ, enhances the antiproliferative effect, and overcomes cross-resistance mechanisms. These results point out that m-NP-based PDT adjuvant therapy is a promising strategy to improve TMZ-based glioblastoma multiforme treatments.

MicroRNA-30a increases the chemosensitivity of U251 glioblastoma cells to temozolomide by directly targeting beclin 1 and inhibiting autophagy

Temozolomide (TMZ) is one of the most commonly used drugs for the clinical treatment of glioblastomas. However, it has been reported that treatment with TMZ can induce autophagy, which leads to tumor resistance and increases the survival of tumor cells. MicroRNA-30a (miR-30a) has been found to have inhibitory effects on autophagy by directly targeting beclin 1. However, the exact role of miR-30a in TMZ-treated glioblastoma cells has not been studied previously. The present study aimed to investigate whether miR-30a increased the cytotoxicity of TMZ to glioblastoma U251 cells, as well as the underlying mechanism. MTT and flow cytometry assay results showed that treatment with TMZ inhibited the proliferation of U251 cells while inducing cell apoptosis in a dose-dependent manner. Western blotting data showed that the expression levels of LC3-II and beclin 1 as well as the ratio of LC3-II to LC3-I were markedly increased in TMZ-treated U251 cells compared with the untreated control cells, indicating that treatment with TMZ induced autophagy. Moreover, reverse transcription-quantitative polymerase chain reaction data showed that treatment with TMZ led to a significant reduction in miR-30a levels in a dose-dependent manner in U251 cells. Elevation of the miR-30a level significantly inhibited TMZ-induced autophagy, demonstrated by the decreased LC3-II and beclin 1 levels and ratio of LC3-II to LC3-I, accompanied by the reduced proliferation and increased apoptosis in TMZ-treated U251 cells. Furthermore, luciferase reporter assay data indicated that beclin 1 was a direct target of miR-30a in U251 cells. In summary, this study demonstrated that miR-30a increases the chemosensitivity of glioblastoma U251 cells to temozolomide by directly targeting beclin 1 and inhibiting autophagy. Therefore, autophagy may be a promising target for the treatment of TMZ-resistant tumors.

NEO212 Inhibits Migration and Invasion of Glioma Stem Cells

Glioblastoma multiforme is a malignant brain tumor noted for its extensive vascularity, aggressiveness, and highly invasive nature, suggesting that cell migration plays an important role in tumor progression. The poor prognosis in GBM is associated with a high rate of tumor recurrence, and resistance to the standard of care chemotherapy, temozolomide (TMZ). The novel compound NEO212, a conjugate of TMZ and perillyl alcohol (POH), has proven to be 10-fold more cytotoxic to glioma stem cells (GSC) than TMZ, and is active against TMZ-resistant tumor cells. In this study, we show that NEO212 decreases migration and invasion of primary cultures of patient-derived GSCs, in both mesenchymal USC02 and proneural USC04 populations. The mechanism by which NEO212 reduces migration and invasion appears to be independent of its DNA alkylating effects, which cause cytotoxicity during the first hours of treatment, and is associated with a decrease in the FAK/Src signaling pathway, an effect not exhibited by TMZ. NEO212 also decreases the production of matrix metalloproteinases MMP2 and MMP9, crucial for GSC invasion. Gene expression analysis of epithelial and mesenchymal markers suggests that NEO212 increases the expression of epithelial-like characteristics, suggesting a reversion of the epithelial-to-mesenchymal transition process. Furthermore, in an in vivo orthotopic glioma model, NEO212 decreases tumor progression by reducing invasion of GSCs, thereby increasing survival time of mice. These studies indicate that NEO212, in addition to cytotoxicity, can effectively reduce migration and invasion in GSCs, thus exhibiting significant clinical value in the reduction of invasion and malignant glioma progression. Mol Cancer Ther; 17(3); 625-37. ©2018 AACR.

SP1 is a transcriptional regulator of URG-4/URGCP gene in hepatocytes

URG-4/URGCP gene was implicated as an oncogene that contributes hepatocarcinogenesis regulated by Hepatitis-B-virus-encoded X antigen. However, the mechanism of transcriptional regulation of this gene remains largely unknown. For this reason, we focused on the functional analyses of URG4/URGCP promoter site. First, 545 bp of URG-4/URGCP, -482/+63, and three different 5'-truncated constructs, -109/+63, -261/+63, -344/+63 were cloned by PCR-based approach into pMetLuc luciferase reporter vector. Transient transfection assay showed that, -109/+63 construct has the highest activity. The promoter of URG-4/URGCP gene contained a CpG island region spanning 400 bp from translation start site. Many SP1/GC boxes, named GC-1 to GC-10 are present in 545 bp of URG-4/URGCP promoter. Because of presence of multiple SP1/GC boxes, promoter constructs were transiently co-transfected with SP1 expression vector to determine the effect of SP1 on URG-4/URGCP promoter activity. Co-transfection analyses induced the basal activity of -268/+63, -344/+63 and -482/+63 constructs. EMSA analysis of GC-4, GC-5, GC-6 and GC-7 binding sites located in -128/-148 bases, showed two DNA-protein binding complexes. Competition assay and super-shifted complexes indicated these complexes are resulted from SP1 binding. Also, site-directed mutagenesis of potential SP1 binding sites diminished both DNA-protein complexes and SP1-mediated upregulation of URG-4 promoter activity. These findings are valuable for understanding transcriptional regulation of URG4/URGCP that has a pivotal role in cancer progression.

Investigation of the effects of a sulfite molecule on human neuroblastoma cells via a novel oncogene URG4/URGCP

AIM

The aim of this study is to determine the anticancer effect of sulfite on SH-SY5Y neuroblastoma cells in vitro conditions and elucidate underlying molecular mechanism of sulfite and explore its therapeutic activity.

MAIN METHODS

In this study, cytotoxic effects of sulfite in SH-SY5Y cels were detected over time in a dose dependent manner with the IC50 doses ranging from 0.5 to 10 mM. Genotoxic effect of sulfite was shown by comet assay. IC50 doses in the SH-SY5Y cells were detected as 5 mM. Expression profiles of the target genes related to apoptosis and cell cycle control were determined by quantitative RT-PCR. Protein changes were determined by western blot analysis.

KEY FINDINGS

URG4/URGCP, CCND1, CCND2, CDK4, CDK6, E2F4 and BCL-2 gene expression levels were significantly reduced and RB1, TP53, BAX, BID, CASP2, CASP3, CASP9 and DIABLO gene expressions were significantly increased in dose group cells. The mechanism of this result may be related to sulfite dependent inhibition of cell cycle at the G1 phase by down-regulating URG4/URGCP or CCND1, CDK4, CDK6 gene expression and stimulating apoptosis via the intrinsic pathway. Sulfite suppressed invasion and colony formation in SH-SY5Y cell line using matrigel invasion chamber and colony formation assay, respectively.

SIGNIFICANCE

It is thought that sulfite demonstrates anticarcinogenesis activity by affecting cell cycle arrest, apoptosis s, invasion, and colony formation on SH-SY5Y cells. Sulfite may be an effective agent for treatment of neuroblastoma as a single agent or in combination with other agents.

A New Epigenetic Mechanism of Temozolomide Action in Glioma Cells

Temozolomide (TMZ) is an oral alkylating chemotherapeutic agent that prolongs the survival of patients with glioblastoma (GBM). Despite that high TMZ potential, progression of disease and recurrence are still observed. Therefore a better understanding of the mechanism of action of this drug is necessary and may allow more durable benefit from its anti-glioma properties. Using nucleotide post-labelling method and separation on thin-layer chromatography we measured of global changes of 5-methylcytosine (m5C) in DNA of glioma cells treated with TMZ. Although m5C is not a product of TMZ methylation reaction of DNA, we analysed the effects of the drug action on different glioma cell lines through global changes at the level of the DNA main epigenetic mark. The first effect of TMZ action we observed is DNA hypermethylation followed by global demethylation. Therefore an increase of DNA methylation and down regulation of some genes expression can be ascribed to activation of DNA methyltransferases (DNMTs). On the other hand hypomethylation is induced by oxidative stress and causes uncontrolled expression of pathologic protein genes. The results of brain tumours treatment with TMZ suggest the new mechanism of modulation epigenetic marker in cancer cells. A high TMZ concentration induced a significant increase of m5C content in DNA in the short time, but a low TMZ concentration at longer time hypomethylation is observed for whole range of TMZ concentrations. Therefore TMZ administration with low doses of the drug and short time should be considered as optimal therapy.