minocycline and Glioma

There are no effective treatments for gliomas after progression on radiation, temozolomide, and bevacizumab. Microglia activation may be involved in radiation resistance and can be inhibited by the brain penetrating antibiotic minocycline. In this phase 1 trial, we examined the safety and effect on survival, symptom burden, and neurocognitive function of reirradiation, minocycline, and bevacizumab.. The trial used a 3 + 3 design for dose escalation followed by a ten person dose expansion. Patients received reirradiation with dosing based on radiation oncologist judgment, bevacizumab 10 mg/kg IV every two weeks, and oral minocycline twice a day. Symptom burden was measured using MDASI-BT. Neurocognitive function was measured using the COGSTATE battery.. The maximum tolerated dose of minocycline was 400 mg twice a day with no unexpected toxicities. The PFS3 was 64.6%, and median overall survival was 6.4 months. Symptom burden and neurocognitive function did not decline in the interval between treatment completion and tumor progression.. Minocycline 400 mg orally twice a day with bevacizumab and reirradiation is well tolerated by physician and patient reported outcomes in people with gliomas that progress on bevacizumab.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Brain Neoplasms; Chemoradiotherapy; Drug Resistance, Neoplasm; Female; Follow-Up Studies; Glioma; Humans; Male; Middle Aged; Minocycline; Neoplasm Grading; Prospective Studies; Retreatment; Survival Rate

Tigecycline is a broad-spectrum, first-in-class glycylcycline antibiotic currently used to treat complicated skin infections and community-acquired pneumonia. However, there is accumulating evidence showing that tigecycline has anticancer properties. In this study, we found tigecycline could inhibit cell proliferation by inducing cell-cycle arrest, but not apoptosis in glioma. To find the underlying mechanism of how tigecycline inhibits cell proliferation, the expression of miRNAs, which were related to regulating cell-cycle progression, was detected with miRNA assay. We found that miR-199b-5p expression was significantly increased after tigecycline treatment, and miR-199b-5p target gene HES1 was downregulated. In addition, the PI3K/AKT pathway was inhibited and p21 expression was increased. When treated with tigecycline and miR-199b-5p antagomir simultaneously in glioma cells, we found that miR-199b-5p antagomir could partly block the effects induced by tigecycline. Tigecycline effectively upregulated miR-199b-5p expression and inhibited tumor growth in the xenograft tumor model of U87 glioma cells. These results suggest that tigecycline may induce cell-cycle arrest and inhibit glioma growth by regulating miRNA-199b-5p-HES1-AKT pathway. Thus, tigecycline is a promising agent in the treatment of malignant gliomas.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Glioma; Humans; Male; MicroRNAs; Minocycline; Proto-Oncogene Proteins c-akt; Rats; RNA Interference; Signal Transduction; Tigecycline; Transcription Factor HES-1; Tumor Burden

The invasiveness of malignant gliomas is one of the major obstacles in glioma therapy and the reason for the poor survival of patients. Glioma cells infiltrate into the brain parenchyma and thereby escape surgical resection. Glioma associated microglia/macrophages support glioma infiltration into the brain parenchyma by increased expression and activation of extracellular matrix degrading proteases such as matrix metalloprotease (MMP) 2, MMP9 and membrane-type 1 MMP. In this work we demonstrate that, MMP9 is predominantly expressed by glioma associated microglia/macrophages in mouse and human glioma tissue but not by the glioma cells. Supernatant from glioma cells induced the expression of MMP9 in cultured microglial cells. Using mice deficient for different Toll-like receptors we identified Toll-like receptor 2/6 as the signaling pathway for the glioma induced upregulation of microglial MMP9. Also in an experimental mouse glioma model, Toll-like receptor 2 deficiency attenuated the upregulation of microglial MMP9. Moreover, glioma supernatant triggered an upregulation of Toll-like receptor 2 expression in microglia. Both, the upregulation of MMP9 and Toll-like receptor 2 were attenuated by the antibiotic minocycline and a p38 mitogen-activated protein kinase antagonist in vitro. Minocycline also extended the survival rate of glioma bearing mice when given to the drinking water. Thus glioma cells change the phenotype of glioma associated microglia/macrophages in a complex fashion using Toll-like receptor 2 as an important signaling pathway and minocycline further proved to be a potential candidate for adjuvant glioma therapy.

Topics: Animals; Anti-Bacterial Agents; Blotting, Western; Brain Neoplasms; Disease Models, Animal; Flow Cytometry; Fluorescent Antibody Technique; Glioma; Humans; Immunoenzyme Techniques; Macrophages; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Microglia; Minocycline; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Toll-Like Receptor 2; Tumor Cells, Cultured

We have reported that minocycline (Mino) induced autophagic death in glioma cells. In the present study, we characterize the upstream regulators that control autophagy and switch cell death from autophagic to apoptotic.. Western blotting and immunofluorescence were used to detect the expressions of eukaryotic translation initiation factor 2α (eIF2α), transcription factor GADD153 (CHOP), and glucose-regulated protein 78 (GRP78). Short hairpin (sh)RNA was used to knock down eIF2α or CHOP expression. Autophagy was assessed by the conversion of light chain (LC)3-I to LC3-II and green fluorescent protein puncta formation. An intracranial mouse model and bioluminescent imaging were used to assess the effect of Mino on tumor growth and survival time of mice.. The expression of GRP78 in glioma was high, whereas in normal glia it was low. Mino treatment increased GRP78 expression and reduced binding of GRP78 with protein kinase-like endoplasmic reticulum kinase. Subsequently, Mino increased eIF2α phosphorylation and CHOP expression. Knockdown of eIF2α or CHOP reduced Mino-induced LC3-II conversion and glioma cell death. When autophagy was inhibited, Mino induced cell death in a caspase-dependent manner. Rapamycin in combination with Mino produced synergistic effects on LC3 conversion, reduction of the Akt/mTOR/p70S6K pathway, and glioma cell death. Bioluminescent imaging showed that Mino inhibited the growth of glioma and prolonged survival time and that these effects were blocked by shCHOP.. Mino induced autophagy by eliciting endoplasmic reticulum stress response and switched cell death from autophagy to apoptosis when autophagy was blocked. These results coupled with clinical availability and a safe track record make Mino a promising agent for the treatment of malignant gliomas.

Topics: Animals; Antineoplastic Agents; Apoptosis; Autophagy; Brain Neoplasms; Cell Line; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2; Glioma; Heat-Shock Proteins; Humans; Mice; Microtubule-Associated Proteins; Minocycline; Rats; Signal Transduction; Transcription Factor CHOP

Minocycline has been shown to alleviate several neurological disorders. Unexpectedly, we found that minocycline had opposite effects on glioma cells: minocycline induced nonapoptotic cell death in glioma cells. The glioma cell death was associated with the presence of autophagic vacuoles in the cytoplasm. Minocycline induced autophagy was confirmed by acridine orange, monodansylcadaverine (MDC) stainings of vesicle formation and the conversion of microtubule-associated proteins light chain 3 (LC3-I) to LC3-II. Pretreatment with autophagy inhibitor 3-methyladenine (3-MA) suppressed the induction of acidic vesicular organelles and the accumulation of LC3-II to the autophagosome membrane in glioma cells treated with minocycline. Despite the pretreatment of 3-MA, minocycline induced cell death which could result from the activation of caspase-3. Minocycline effectively inhibited tumor growth and induced autophagy in the xenograft tumor model of C6 glioma cells. These results suggest that minocycline may kill glioma cells by inducing autophagic cell death. When autophagy was inhibited, minocycline still induced cell death through the activation of caspase-3. Thus, minocycline is a promising agent in the treatment of malignant gliomas.

Topics: Adenine; Animals; Astrocytes; Autophagy; Cell Line, Tumor; Cell Proliferation; Gene Knockdown Techniques; Glioma; Mice; Mice, Nude; Minocycline; Organelles; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Small Interfering; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Glioma cells release soluble factors, which induce the expression of membrane type 1 matrix metalloprotease (MT1-MMP) in tumor associated microglia and then exploit MT1-MMP mediated matrix degradation for invasion. Here, we show that minocycline blocked the increase in MT1-MMP expression and activity in cultivated microglia stimulated with glioma conditioned medium. Glioma growth within an organotypic brain slice preparation was reduced by minocycline and this reduction depended on the presence of microglia. Glioma growth in an experimental mouse model was strongly reduced by the addition of minocycline to drinking water, compared to untreated controls. Coherently, we observed in our orthotopic glioma implantation model, that MT1-MMP was abundantly expressed in glioma associated microglia in controls, but was strongly attenuated in tumors of minocycline treated animals. Overall, our study indicates that the clinically approved antibiotic minocycline is a promising new candidate for adjuvant therapy against malignant gliomas.

Topics: Animals; Antibiotics, Antineoplastic; Brain Neoplasms; Cells, Cultured; Chemotherapy, Adjuvant; Culture Media, Conditioned; Glioma; Matrix Metalloproteinase 14; Mice; Microglia; Minocycline; Neoplasm Invasiveness; Neoplasms, Experimental; Organ Culture Techniques

The tumor microenvironment is considered to play an important role in tumor formation and progression by providing both negative and positive signals that influence tumor cell growth. We and others have previously shown that brain tumor (glioma) formation in Nf1 genetically engineered mice requires a microenvironment composed of cells heterozygous for a targeted Nf1 mutation. Using NF1 as a model system to understand the contribution of the tumor microenvironment to glioma formation, we show that Nf1+/- brain microglia produce specific factors that promote Nf1-/- astrocyte growth in vitro and in vivo and identify hyaluronidase as one of these factors in both genetically engineered Nf1 mouse and human NF1-associated optic glioma. We further demonstrate that blocking hyaluronidase ameliorates the ability of Nf1+/- microglia to increase Nf1-/- astrocyte proliferation and that hyaluronidase increases Nf1-/- astrocyte proliferation in an MAPK-dependent fashion. Lastly, inhibiting microglia activation in genetically engineered Nf1 mice significantly reduces mouse optic glioma proliferation in vivo. Collectively, these studies identify Nf1+/- microglia as an important stromal cell type that promotes Nf1-/- astrocyte and optic glioma growth relevant to the pathogenesis of NF1-associated brain tumors and suggest that future brain therapies might be directed against paracrine factors produced by cells in the tumor microenvironment.

Topics: Animals; Astrocytes; Blotting, Western; Brain; Cell Proliferation; Cells, Cultured; Enzyme-Linked Immunosorbent Assay; Glioma; Heterozygote; Humans; Hyaluronan Receptors; Hyaluronoglucosaminidase; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Minocycline; Neurofibromin 1; Oligonucleotide Array Sequence Analysis; Reverse Transcriptase Polymerase Chain Reaction