Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0598934 (tumor growth)
 58,965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glioma is the most common malignant primary brain tumor. Its rapid growth is aided by tumor-mediated glutamate release, creating peritumoral excitotoxic cell death and vacating space for tumor expansion. Glioma glutamate release may also be responsible for seizures, which complicate the clinical course for many patients and are often the presenting symptom. A hypothesized glutamate release pathway is the cystine/glutamate transporter System xc (-) (SXC), responsible for the cellular synthesis of glutathione (GSH). However, the relationship of SXC-mediated glutamate release, seizures, and tumor growth remains unclear. Probing expression of SLC7A11/xCT, the catalytic subunit of SXC, in patient and mouse-propagated tissues, we found that ~50% of patient tumors have elevated SLC7A11 expression. Compared with tumors lacking this transporter, in vivo propagated and intracranially implanted SLC7A11-expressing tumors grew faster, produced pronounced peritumoral glutamate excitotoxicity, induced seizures, and shortened overall survival. In agreement with animal data, increased SLC7A11 expression predicted shorter patient survival according to genomic data in the REMBRANDT (National Institutes of Health Repository for Molecular Brain Neoplasia Data) database. In a clinical pilot study, we used magnetic resonance spectroscopy to determine SXC-mediated glutamate release by measuring acute changes in glutamate after administration of the U.S. Food and Drug Administration-approved SXC inhibitor, sulfasalazine (SAS). In nine glioma patients with biopsy-confirmed SXC expression, we found that expression positively correlates with glutamate release, which is acutely inhibited with oral SAS. These data suggest that SXC is the major pathway for glutamate release from gliomas and that SLC7A11 expression predicts accelerated growth and tumor-associated seizures.
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PMID:SLC7A11 expression is associated with seizures and predicts poor survival in patients with malignant glioma. 2860 29

Growth of cancer cells is more highly dependent on various types of amino acids than that of normal cells, and thus prevention of amino acid requirement has been recognized as strategies for cancer therapies. In this study, we found that deprivation of cysteine (Cys) in culturing media prevented the growth of various types of human cancer cell lines. Cys is easily converted to cystine (Cys-Cys) in media and uptaken into cells by cystine/glutamate transporter (xCT). The incorporated Cys-Cys is decomposed into Cys, and used for synthesis of glutathione that suppresses reactive oxygen species-induced cell damage. Therefore, we examined whether a selective xCT inhibitor erastin prevented the growth of human cancer cell lines. As a result, erastin significantly prevented the proliferation of various types of human cancer cells. Among them, MDA-MB-231 breast cancer cells were identified as the most erastin-sensitive cells. To investigate the ability of erastin to prevent growth of tumor in mice, MDA-MB-231 breast cancer cells were implanted into BALB/c nude female mice kept under standardized light/dark cycle conditions. The growth of tumor implanted in mice was significantly suppressed by administration of erastin during the light phase, whereas its administration during the dark phase failed to suppress the tumor growth. The dosing time-dependency of erastin-induced cystine/cysteine deprivation was closely related to that of its anti-tumor effects. Our present findings suggest that the anti-tumor efficacy of erastin in tumor-bearing mice is improved by optimizing the dosing schedule.
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PMID:Dosing Time-Dependent Changes in the Anti-tumor Effect of xCT Inhibitor Erastin in Human Breast Cancer Xenograft Mice. 3168 75

System xc- cystine/glutamate antiporter, composed of a light-chain subunit (xCT, SLC7A11) and a heavy-chain subunit (CD98hc, SLC3A2), is mainly responsible for the cellular uptake of cystine in exchange for intracellular glutamate. In recent years, the xCT molecule has been found to play an important role in tumor growth, progression, metastasis, and multidrug resistance in various types of cancer. Interestingly, xCT also exhibits an essential function in regulating tumor-associated ferroptosis. Despite significant progress in targeting the system xc- transporter in cancer treatment, the underlying mechanisms still remain elusive. It is also unclear why solid tumors are more sensitive to xCT inhibitors such as sulfasalazine, as compared to hematological malignancies. This review mainly focuses on the role of xCT cystine/glutamate transporter in regard to tumor growth, chemoresistance, tumor-selective ferroptosis, and the mechanisms regulating xCT gene expression. The potential therapeutic implications of targeting the system xc- and its combination with chemotherapeutic agents or immunotherapy to suppress tumor growth and overcome drug resistance are also discussed.
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PMID:xCT: A Critical Molecule That Links Cancer Metabolism to Redox Signaling. 3293 51