Antitumor Effect Of Temozolomide Research Articles

Long acting tariquidar loaded stearic acid-modified hydroxyapatite enhances brain penetration and antitumor effect of temozolomide

Temozolomide (TMZ) is the first line chemotherapy for glioblastoma (GBM) treatment, but the P-glycoprotein (P-gp) expressed in blood–brain barrier (BBB) will pump out TMZ from the brain leading to decreased TMZ concentration. Tariquidar (TQD), a selective and potent P-gp inhibitor, may be suitable for combination therapy to increase concentration of TMZ in brain. Hydroxyapatite (HAP) is a biodegradable material with sustained release characteristics, and stearic acid surface-modified HAP (SA-HAP) can increase hydrophobicity to facilitate TQD loading. TQD-loaded stearic acid surface-modified HAP (SA-HAP-TQD) was prepared with optimal size and high TQD loading efficiency, and in vitro release and cellular uptake of SA-HAP-TQD showed that SA-HAP-TQD were taken up into lysosome and continuously released TQD from macrophages. In vivo studies have found that over 70 % of SA-HAP was degraded and 80 % of TQD was released from SA-HAP-TQD 28 days after administration. SA-HAP-TQD could increase brain penetration of TMZ, but it would not enhance adverse effects of TMZ in healthy mice. SA-HAP-TQD and TMZ combination had longer median survival than TMZ single therapy in GL261 orthotopic model. These results suggest that SA-HAP-TQD has sustained release characteristics and are potential for improving antitumor effect with TMZ treatment.

Lomustine and nimustine exert efficient antitumor effects against glioblastoma models with acquired temozolomide resistance.

Glioblastomas (GBM) often acquire resistance against temozolomide (TMZ) after continuous treatment and recur as TMZ‐resistant GBM (TMZ‐R‐GBM). Lomustine (CCNU) and nimustine (ACNU), which were previously used as standard therapeutic agents against GBM before TMZ, have occasionally been used for the salvage therapy of TMZ‐R‐GBM; however, their efficacy has not yet been thoroughly examined. Therefore, we investigated the antitumor effects of CCNU and ACNU against TMZ‐R‐GBM. As a model of TMZ‐R‐GBM, TMZ resistant clones of human GBM cell lines (U87, U251MG, and U343MG) were established (TMZ‐R‐cells) by the culture of each GBM cells under continuous TMZ treatment, and the antitumor effects of TMZ, CCNU, or ACNU against these cells were analyzed in vitro and in vivo. As a result, although growth arrest and apoptosis were triggered in all TMZ‐R‐cells after the administration of each drug, the antitumor effects of TMZ against TMZ‐R‐cells were significantly reduced compared to those of parental cells, whereas CCNU and ACNU demonstrated efficient antitumor effects on TMZ‐R‐cells as well as parental cells. It was also demonstrated that TMZ resistance of TMZ‐R‐cells was regulated at the initiation of DNA damage response. Furthermore, survival in mice was significantly prolonged by systemic treatment with CCNU or ACNU but not TMZ after implantation of TMZ‐R‐cells. These findings suggest that CCNU or ACNU may serve as a therapeutic agent in salvage treatment against TMZ‐R‐GBM.

A Human iPSC-derived 3D platform using primary brain cancer cells to study drug development and personalized medicine

A high throughput histology (microTMA) platform was applied for testing drugs against tumors in a novel 3D heterotypic glioblastoma brain sphere (gBS) model consisting of glioblastoma tumor cells, iPSC-derived neurons, glial cells and astrocytes grown in a spheroid. The differential responses of gBS tumors and normal neuronal cells to sustained treatments with anti-cancer drugs temozolomide (TMZ) and doxorubicin (DOX) were investigated. gBS were exposed to TMZ or DOX over a 7-day period. Untreated gBS tumors increased in size over a 4-week culture period, however, there was no increase in the number of normal neuronal cells. TMZ (100 uM) and DOX (0.3 uM) treatments caused ~30% (P~0.07) and ~80% (P < 0.001) decreases in the size of the tumors, respectively. Neither treatment altered the number of normal neuronal cells in the model. The anti-tumor effects of TMZ and DOX were mediated in part by selective induction of apoptosis. This platform provides a novel approach for screening new anti-glioblastoma agents and evaluating different treatment options for a given patient.

Antitumor effect of levetiracetam combined with temozolomide in glioma cell lines.

e13530 Background: The antitumor effect oftemozolomide (TMZ) is still remitted for portion of glioma patients, and if anti-epilepcy drug levetiracetam (LEV) may help TMZ for anti-glioma is not clear. Methods: The cell proliferation with Cell Counting Kit-8 (CCK-8) assay was performed in two O6-methylguanine DNA methyltransferase (MGMT) positive cell lines (T98G and U138) and two other MGMT negative cell lines (SKMG-4 and U87). The cells were treated with LEV and TMZ alone or in combination. Results: LEV inhibited the proliferation of glioma cell lines but not reach therapeutic effect, especially in U87cell line. The 50% inhibitory concentration (IC50) of TMZ was significantly decreased in cell lines (T98G, U138 and SKMG-4, P&lt; 0.05) which were treated with TMZ and LEV, but no significantly changed in U87 (P&gt; 0.05). Conclusions: LEV may inhibit the proliferation of glioma cell lines (both MGMT- positive and MGMT-negative) and also sensitizes cell lines (T98G, U138 and SKMG-4, but not U87) to TMZ.

P17.63 * COMBINATION THERAPY WITH TEMOZOLOMIDE, INTERFERON-BETA, AND RIBAVIRIN IN GLIOMA CELL LINES

INTRODUCTION: Although Temozolomide (TMZ) with radiotherapy significantly improves the survival of newly diagnosed glioblastoma although most patients develop tumor progression within 1-2 years. The Japan Clinical Oncology Group (JCOG) are ongoing a phase II randomized study to evaluate the clinical effectiveness of TMZ and Interferon-β (IFN-β) combination therapy in glioblastoma patients. Meanwhile, Ribavirin (RBV) is a standard agent of treating of chronic hepatitis C together with interferon-α. Recently, an anti-tumor effect of RBV was reported in breast cancer and chronic myelocytic leukemia. We evaluated the effect of TMZ, IFN-β, and RBV combination therapy in glioma cell lines. METHODS: Glioma cell lines used were A-172, AM-38, T98G, U-87MG, U-138MG, U-251MG, and YH-13. Glioma cell lines were cultured in an incubator for 48 hours and administered with either 1. TMZ (10 µM) + IFN-β (10 IU/ml) or 2. TMZ (10 µM) + IFN-β (10 IU/ml) + RBV (10 µM). At 72 to 96 hours post-treatment, the number of remaining glioma cells were counted to evaluate the growth-inhibitory effects of each therapy. In addition, cell cycle changes by flow cytemetry and p53 activity with western blot analysis were examined from U-87 MG cell line. RESULTS AND CONCLUSIONS: In all cell lines, the triple combination therapy enhanced the growth-inhibitory effect compared to dual combination therapy. Triple therapy led to distribution of G2/M phase of the cell cycle and accumulated p53 activety. Rivabirin enhanced antitumor effect of TMZ and IFN combination therapy in glioma cell lines.

Propolis changes the anticancer activity of temozolomide in U87MG human glioblastoma cell line

BackgroundPropolis is a honey bee product which contains many active compounds, such as CAPE or chrysin, and has many beneficial activities. Recently, its anti-tumor properties have been discussed. We have tested whether the ethanolic extract of propolis (EEP) interferes with temozolomide (TMZ) to inhibit U87MG cell line growth.MethodsThe U87MG glioblastoma cell line was exposed to TMZ (10-100 μM), EEP (10-100 μg/ml) or a mixture of TMZ and EEP during 24, 48 or 72 hours. The cell division was examined by the H3-thymidine incorporation, while the western blot method was used for detection of p65 subunit of NF-κB and ELISA test to measure the concentration of its p50 subunit in the nucleus.ResultsWe have found that both, TMZ and EEP administrated alone, had a dose- and time-dependent inhibitory effect on the U87MG cell line growth, which was manifested by gradual reduction of cell viability and alterations in proliferation rate. The anti-tumor effect of TMZ (20 μM) was enhanced by EEP, which was especially well observed after a short time of exposition, where simultaneous usage of TMZ and EEP resulted in a higher degree of growth inhibition than each biological factor used separately. In addition, cells treated with TMZ presented no changes in NF-κB activity in prolonged time of treatment and EEP only slightly reduced the nuclear translocation of this transcription factor. In turn, the combined incubation with TMZ and EEP led to an approximately double reduction of NF-κB nuclear localization.ConclusionsWe conclude that EEP presents cytotoxic properties and may cooperate with TMZ synergistically enhancing its growth inhibiting activity against glioblastoma U87MG cell line. This phenomenon may be at least partially mediated by a reduced activity of NF-κB.

Resveratrol Enhances the Antitumor Effects of Temozolomide in Glioblastoma via ROS‐dependent AMPK‐TSC‐mTOR Signaling Pathway

Resveratrol has been regarded as a promising candidate for cancer prevention and treatment. The present study was to investigate the impact of resveratrol on the antitumor effects of temozolomide (TMZ), a standard treatment regiment of glioblastoma (GBM), in vitro and in vivo. We found that the combination of resveratrol and TMZ significantly resulted in G(2)/M cell cycle arrest by flow cytometry, triggered a robust increase in expression of astrocyte differentiation marker glial fibrillary acid protein (GFAP), downregulated the expression of matrix metalloproteinase-9 (MMP-9) by immunohistochemistry and western blot analysis as well as inhibited cell migration by scratch wound assay. Further study revealed that TMZ in combination with resveratrol remarkably increased reactive oxygen species (ROS) production, which serves as an upstream signal for AMP-activated protein kinase (AMPK) activation. Subsequently, activated AMPK inhibited mTOR signaling and downregulated antiapoptosis protein Bcl-2, which was contributed to the additive antiproliferation effects of combination treatment. In an orthotopic xenograft model of GBM, TMZ plus resveratrol treatment significantly reduced the volume of tumor, which was confirmed by decreased expression of Ki-67, a marker of proliferation index. Our findings demonstrate for the first time that resveratrol can enhance TMZ-mediated antitumor effects in GBM in vitro and in vivo, via ROS-dependent AMPK-TSC-mTOR signaling pathway.

Abstract 5754: Temozolomide therapy for progressive metastatic paraganglioma/pheochromocytoma: SDHB mutation as a prognosis biomarker for efficacy

Abstract Malignant pheochromocytoma and paraganglioma (PPGLs) are rare diseases with a heterogeneous behaviour. Nowadays systemic therapies, including 131I-MIBG therapy and the cyclophosphamide-dacarbazine-vincristine chemotherapy regimen (CVD), constitute the most popular options in case of aggressive tumors. We have investigated the antitumor effect of temozolomide (TMZ), in patients with metastatic PPGLs. All patients were assessed for TMZ efficacy, with CT scan and PET scan performed every 3 months. Safety and identification for prognosis factors of response were secondary endpoints. Fifteen consecutive patients with progressive (n=14) or symptomatic (n=1) metastatic PPGLs began TMZ therapy at our institution between November 2007 and January 2011. There were 12 men (80%); median age was 43 years, with a functioning tumor in 73% of the cases. Germline mutations were screened: 10 patients harbored SDH B mutation and 5 patients had no mutation among SDH A, SDH C, SDH D, NF1, RET or VHL genes. Primary was located in the adrenal gland for 53% of the patients, thorax for 40 % and neck for 7%. TMZ was given at a dose of 150 mg/m2/d for five days of a 28-days cycle for the first cycle and then at 200 mg/m2 for five days each subsequent cycle. Seven patients received TMZ as first line therapy, 2 patients as second line and 6 patients as third line. Median number of cycle administered was 7, mean dose intensity was 171 mg/m2 (95% CI 160.7-181) for each treatment cycle. TMZ was well tolerated: the most frequent all grade toxicities included asthenia, nausea and anemia. Grade 3 toxicities were lymphopenia (n=2) and hypertension (n=1). According to RECIST 1.1 criteria, 11 patients were evaluable: 4 patients experienced a partial response, 6 a stable disease, 1 patient a progressive disease. With a median follow up of 29 months (range 6.4-37.9), median overall survival was not reached and median progression free survival (PFS) was 9.6 months. Partial response was observed in 4 out of 10 SDHB mutated patients but no sporadic case. Patients with SDH B mutations or with no mutation had a median PFS of 16.7 months or 2.6 months, respectively (log-rank, p=0.013); Patients with SDH B mutations or with no mutation had a 12-month PFS of 60% or 0%, respectively. Expression of Methyl Guanine Methyl Transferase (MGMT) by immunohistochemistry (IHC) was analyzed in 4 patients, including 3 responders and, was found negative. MGMT IHC is ongoing in the remaining patients This study demonstrates for the first time the antitumor efficacy of TMZ in a large series of metastatic PPGLs as well as the potential role for SDH B mutation as a prognosis biomarker of response of response. Loss of MGMT expression in SDH B mutated patients could explain these results. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5754. doi:1538-7445.AM2012-5754

Anti-galectin-1 siRNA delivery in nude mice bearing human glioblastoma model increases the antitumor effects of temozolomide with severe impairment of angiogenesis

Anti-galectin-1 siRNA delivery in nude mice bearing human glioblastoma model increases the antitumor effects of temozolomide with severe impairment of angiogenesis

Role of autophagy in temozolomide-induced cytotoxicity for malignant glioma cells.

Autophagy is originally named as a process of protein recycling. It begins with sequestering cytoplasmic organelles in a membrane vacuole called autophagosome. Autophagosomes then fuse with lysosomes, where the materials inside are degraded and recycled. To date, however, little is known about the role of autophagy in cancer therapy. In this study, we present that temozolomide (TMZ), a new alkylating agent, inhibited the viability of malignant glioma cells in a dose-dependent manner and induced G2/M arrest. At a clinically achievable dose (100 microM), TMZ induced autophagy, but not apoptosis in malignant glioma cells. After the treatment with TMZ, microtubule-associated protein light-chain 3 (LC3), a mammalian homologue of Apg8p/Aut7p essential for amino-acid starvation-induced autophagy in yeast, was recruited on autophagosome membranes. When autophagy was prevented at an early stage by 3-methyladenine, a phosphatidylinositol 3-phosphate kinase inhibitor, not only the characteristic pattern of LC3 localization, but also the antitumor effect of TMZ was suppressed. On the other hand, bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase, that prevents autophagy at a late stage by inhibiting fusion between autophagosomes and lysosomes, sensitized tumor cells to TMZ by inducing apoptosis through activation of caspase-3 with mitochondrial and lysosomal membrane permeabilization, while LC3 localization pattern stayed the same. These results indicate that TMZ induces autophagy in malignant glioma cells. Application of an autophagy inhibitor that works after the association of LC3 with autophagosome membrane, such as bafilomycin A1, is expected to enhance the cytotoxicity of TMZ for malignant gliomas.