Cycle Pathway Genes Research Articles

Gene expression and energetic metabolism changes in the whiteleg shrimp (Litopenaeus vannamei) in response to short‐term hypoxia

In shrimp, several physiological, metabolic and gene expression patterns related to the use of carbohydrates have been associated with hypoxia since this limiting factor modifies aerobic glycolysis to anaerobic glycolysis. The aim of this work was to analyse the effect of short-term hypoxia on oxygen consumption (OC), carbohydrate content and expression of hypoxia inducible factor 1 (HIF-1), glycolysis and Krebs’ cycle genes in Litopenaeus vannamei juvenile shrimps to elucidate use of energy in shrimps during the periods of low oxygen concentration commonly found in culture ponds. At low oxygen concentration, a decrease in shrimp OC, an increase in carbohydrate content and an increase in expression of HIF-1, glycolysis and Krebs’ cycle genes in shrimp gills were registered. These results might indicate that exposure of L. vannamei to short-term hypoxia implies the use of carbohydrates as metabolic fuel triggered by an increase in transcription of HIF-1, glycolysis and Krebs’ cycle pathway genes, as a strategy to maintain a balance between oxidative and anaerobic metabolism and to sustain the energy supply as a compensation to low oxygen availability.

Abstract 3944: Blockage of EGFR signaling repurposes tumor metabolism through suppression of glycolysis and Kreb cycle in head and neck cancer

Abstract Head and neck squamous cell carcinoma (HNSCC), the most common malignant neoplasm arising in the mucosa of the upper aerodigestive tract, remains a significant cause of morbidity worldwide. With respect to the cancer treatment, HNSCC has a moderately good survival rate, however, the disease often recurs, leading to a poor prognostic disease course and tends to fail in treatment. The metabolic properties of cancer cells diverge significantly from those of normal cells. Emerging evidence suggests these metabolic alterations are also linked to therapeutic resistance in cancer treatment. EGFR targeted agents currently approved or under investigation for HNSCC. We recently identified a novel EGFR tyrosine kinase inhibitor (EGFR-TKI), BPR3K007S0, and found that this compound significantly inhibited EGFR phosphorylation in EGFR-overexpressing HNSCC cells in vitro and in vivo than that of gefitinib. BPR3K007S0 significantly suppressed the expression of a wide range of metabolic genes, including metabolic-related transcription factors, glycolysis, TCA cycle, and pentose phosphate pathway genes. Collectively, we also found that BPR3K007S0 significantly decreased glycolytic and mitochondria respiratory capacity. Pharmacological and genetic manipulation demonstrated that c-Myc/hexokinase 2 axis was one of downstream effector in response to EGFR inhibition. Furthermore, we found that EGFR-TKIs were able to suppress succinate dehydrogenase A leading to reduce fumarate, an oncometabolite generates from Kreb cycle, and contributed to EGFR-TKIs mediated antitumor effect. Taken together, these results revealed that blockage of EGFR signaling repurposes tumor metabolism through suppression of hexokinase 2 and succinate dehydrogenase A, in glycolysis and Kreb cycle, respectively, and demonstrated added benefits to treatment of HNSCCs. Citation Format: Ching-Chuan Kuo, Jang-Yang Chang, Hsing-Pang Hsieh, Hsing-Jien Kung, Hsih-Huei Chang, Chih-Hsiang Huang, Cheng-Chin Kuo, Yi-Yu Ke. Blockage of EGFR signaling repurposes tumor metabolism through suppression of glycolysis and Kreb cycle in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3944.

Abstract 4463: Riluzole effectively modulates cell cycle and cell death in a molecularly diverse set of breast cancer cell lines

Abstract Metabotropic glutamate receptor 1 (GRM1) has an established oncogenic role in melanoma. Growing evidence supports a similar role in breast cancer. We have previously shown that GRM1 is not only expressed in human breast cancers, but that levels of expression correlate with clinical outcomes with tamoxifen treatment, and that GRM1 knockdown reduces breast cancer cell viability and growth. Others have shown that GRM1 modulating drugs also reduce viability and growth of estrogen receptor (ER) negative breast cancer cell lines. Riluzole, a postulated inhibitor of glutamate release, has been evaluated in pre-clinical studies in melanoma. Early clinical trials have shown promising results for this disease. However, the mechanistic effects of riluzole have not been well-defined. Therefore, we evaluated the functional activity of riluzole in breast cancer. A molecularly diverse set of ER+ and ER- breast cancer cell lines with variable GRM1 expression were evaluated. Cell lines were treated with either riluzole or BAY 36-7620 (non-competitive GRM1 antagonist) or their combination. Treatment with either drug reduces cell number and viability, inhibits cell proliferation, and alters expression of cell cycle and apoptotic pathway genes as determined by gene microarray analysis. Drug treatment produces cell line-dependent effects on markers for proliferation, cell cycle, DNA damage, and apoptosis. Riluzole induces G2/M arrest in all cell lines tested. More specifically, riluzole induces mitotic arrest as demonstrated by changes in histone H3 phosphorylation at serine 10 and cyclin B level. Treatment with BAY 36-7620 induces a modest G2/M arrest and increase in the sub G1 population in a subset of cell lines. However, BAY 36-7620 does not induce mitotic arrest. The combination of riluzole and BAY 36-7620 results in increased cell death and decreased proliferation in all cell lines tested. Our data suggest that either riluzole or BAY 36-7620 induce breast cancer cell death. However, riluzole may modulate the activity of intracellular targets independent of GRM1. As riluzole is an FDA-approved drug, it could be quickly moved into a clinical trial and may provide a novel therapeutic approach in the treatment of breast cancer. Citation Format: Sonia C. Dolfi, Daniel J. Medina, Shridar Ganesan, Alexei Vazquez, Kim M. Hirshfield. Riluzole effectively modulates cell cycle and cell death in a molecularly diverse set of breast cancer cell lines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4463. doi:10.1158/1538-7445.AM2015-4463

Abstract 4349: Therapeutic radiation induces an epigenetic DNA methylation response

Abstract Therapeutic radiation results in a cascade of cellular events culminating either in repair of DNA damage and cell survival, or failure to repair damage and cell death. Gene expression is partially under epigenetic control in the form of DNA methylation. We investigated whole genome DNA methylation profiles of MDA-MB-231 breast cancer cells following therapeutic radiation to determine genes and pathways that are differentially methylated. MDA-MB-231 cells were treated with a single dose of 0, 2, or 6 Gy and incubated at 1, 2 4, 8, 24, 48, and 72 hrs before obtaining DNA extracts. DNA was subjected to whole genome DNA methylation profile analysis using an Infinium BeadArray which has the ability to determine CpG methylation at 450,000 genomic sites and covering all genes. Compared to unirradiated cells, 2 and 6 Gy irradiated cells showed 419-1661 CpG sites with decreased methylation and 514-2657 CpG sites with increased methylation, depending on time and dose. The number of hypomethylated genes in 2 Gy irradiated cells increased over time while the number of hypermethylated genes decreased in the first 8 hrs and then increased to a maximum at 72 hrs. In 6 Gy irradiated cells, no pattern was detected, although there was overall more DNA methylation changes than in 2 Gy irradiated cells, indicated a dose effect. Gene ontology analysis using Genomatix Genome Analyzer showed significant changes in DNA repair, cell cycle, apoptosis, and cell survival pathway gene methylation. DNA repair genes were differentially methylated as early as 1 hr after irradiation and sustained through 72 hrs. Epigenetic changes persisted after DNA repair, as shown by gamma-H2AX immunofluorescence, had taken place. Cell cycle, cyclin-dependent kinase, and cyclin-dependent kinase inhibitor genes were differentially methylated 4-24 hrs post-irradiation, correlating with a G2 cell cycle arrest as determined by flow cytometry. These data suggest that epigenetic regulation in the form of DNA methylation is integrated with the cellular response to radiation. 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 4349. doi:1538-7445.AM2012-4349