Drug resistance in diploid yeast is acquired through dominant alleles, haploinsufficiency, gene duplication and aneuploidy

Previous studies of adaptation to the glucose analog, 2-deoxyglucose, by Saccharomyces cerevisiae have utilized haploid cells. In this study, diploid cells were used in the hope of identifying the distinct genetic mechanisms used by diploid cells to acquire drug resistance. While haploid cells acquire resistance to 2-deoxyglucose primarily through recessive alleles in specific genes, diploid cells acquire resistance through dominant alleles, haploinsufficiency, gene duplication and aneuploidy. Dominant-acting, missense alleles in all three subunits of yeast AMP-activated protein kinase confer resistance to 2-deoxyglucose. Dominant-acting, nonsense alleles in the REG1 gene, which encodes a negative regulator of AMP-activated protein kinase, confer 2-deoxyglucose resistance through haploinsufficiency. Most of the resistant strains isolated in this study achieved resistance through aneuploidy. Cells with a monosomy of chromosome 4 are resistant to 2-deoxyglucose. While this genetic strategy comes with a severe fitness cost, it has the advantage of being readily reversible when 2-deoxyglucose selection is lifted. Increased expression of the two DOG phosphatase genes on chromosome 8 confers resistance and was achieved through trisomies and tetrasomies of that chromosome. Finally, resistance was also mediated by increased expression of hexose transporters, achieved by duplication of a 117 kb region of chromosome 4 that included the HXT3, HXT6 and HXT7 genes. The frequent use of aneuploidy as a genetic strategy for drug resistance in diploid yeast and human tumors may be in part due to its potential for reversibility when selection pressure shifts.

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Hypoxia promotes drug resistance in osteosarcoma cells via activating AMP-activated protein kinase (AMPK) signaling

Journal of Bone Oncology ◽

10.1016/j.jbo.2016.01.002 ◽

2016 ◽

Vol 5 (1) ◽

pp. 22-29 ◽

Cited By ~ 17

Author(s):

Changfu Zhao ◽

Qiao Zhang ◽

Tao Yu ◽

Shudong Sun ◽

Wenjun Wang ◽

...

Keyword(s):

Drug Resistance ◽

Protein Kinase ◽

Osteosarcoma Cells ◽

Ampk Signaling ◽

Amp Activated Protein Kinase

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So Many Roads: the Multifaceted Regulation of Autophagy Induction

Molecular and Cellular Biology ◽

10.1128/mcb.00303-18 ◽

2018 ◽

Vol 38 (21) ◽

Cited By ~ 36

Author(s):

Angel F. Corona Velazquez ◽

William T. Jackson

Keyword(s):

Saccharomyces Cerevisiae ◽

Drosophila Melanogaster ◽

Caenorhabditis Elegans ◽

Protein Kinase ◽

Negative Regulator ◽

Content Type ◽

Signaling Complex ◽

Autophagy Induction ◽

Regulatory Complex ◽

Amp Activated Protein Kinase

ABSTRACT Autophagy is an evolutionary conserved, degradative process from single-cell eukaryotes, such as Saccharomyces cerevisiae, to higher mammals, such as humans. The regulation of autophagy has been elucidated through the combined study of yeast, Caenorhabditis elegans, mice, Drosophila melanogaster, and humans. MTOR, the major negative regulator of autophagy, and activating nutrient kinases, such as 5′-AMP-activated protein kinase (AMPK), interact with the autophagy regulatory complex: ULK1/2, RB1CC1, ATG13, and ATG101. The ULK1/2 complex induces autophagy by phosphorylating downstream autophagy complexes, such as the BECN1 PIK3 signaling complex that leads to the creation of LC3+ autophagosomes. We highlight in this review various reports of autophagy induction that are independent of these regulators. We discuss reports of MTOR-independent, AMPK-independent, ULK1/2-independent, and BECN1-PIK3C3-independent autophagy. We illustrate that autophagy induction and the components required vary by the nature of the induction signal and type of cell and do not always require canonical members of the autophagy signaling pathway. We illustrate that rather than thinking of autophagy as a linear pathway, it is better to think of autophagy induction as an interconnecting web of key regulators, many of which can induce autophagy through different requirements depending on the type and length of induction signals.

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Regulation of AMP-activated Protein Kinase Signaling by AFF4 Protein, Member of AF4 (ALL1-fused Gene from Chromosome 4) Family of Transcription Factors, in Hypothalamic Neurons

Journal of Biological Chemistry ◽

10.1074/jbc.m112.367854 ◽

2012 ◽

Vol 287 (24) ◽

pp. 19985-19996 ◽

Cited By ~ 8

Author(s):

Tadasuke Komori ◽

Asako Doi ◽

Tetsuya Nosaka ◽

Hiroto Furuta ◽

Takashi Akamizu ◽

...

Keyword(s):

Transcription Factors ◽

Protein Kinase ◽

Chromosome 4 ◽

Kinase Signaling ◽

Hypothalamic Neurons ◽

Fused Gene ◽

Amp Activated Protein Kinase ◽

Protein Kinase Signaling

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Salinomycin Activates AMP-Activated Protein Kinase-Dependent Autophagy in Cultured Osteoblastoma Cells: A Negative Regulator against Cell Apoptosis

PLoS ONE ◽

10.1371/journal.pone.0084175 ◽

2013 ◽

Vol 8 (12) ◽

pp. e84175 ◽

Cited By ~ 36

Author(s):

Lun-qing Zhu ◽

Yun-fang Zhen ◽

Ya Zhang ◽

Zhi-xiong Guo ◽

Jin Dai ◽

...

Keyword(s):

Protein Kinase ◽

Cell Apoptosis ◽

Negative Regulator ◽

Amp Activated Protein Kinase

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EGFR inhibition evokes innate drug resistance in lung cancer cells by preventing Akt activity and thus inactivating Ets-1 function

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1510733112 ◽

2015 ◽

Vol 112 (29) ◽

pp. E3855-E3863 ◽

Cited By ~ 53

Author(s):

Janyaporn Phuchareon ◽

Frank McCormick ◽

David W. Eisele ◽

Osamu Tetsu

Keyword(s):

Lung Cancer ◽

Drug Resistance ◽

Protein Kinase ◽

Transcriptional Activation ◽

Target Genes ◽

Mapk Pathway ◽

Negative Regulator ◽

Mitogen Activated Protein Kinase ◽

Egfr Inhibition ◽

Egfr Tkis

Nonsmall cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. About 14% of NSCLCs harbor mutations in epidermal growth factor receptor (EGFR). Despite remarkable progress in treatment with tyrosine kinase inhibitors (TKIs), only 5% of patients achieve tumor reduction >90%. The limited primary responses are attributed partly to drug resistance inherent in the tumor cells before therapy begins. Recent reports showed that activation of receptor tyrosine kinases (RTKs) is an important determinant of this innate drug resistance. In contrast, we demonstrate that EGFR inhibition promotes innate drug resistance despite blockade of RTK activity in NSCLC cells. EGFR TKIs decrease both the mitogen-activated protein kinase (MAPK) and Akt protein kinase pathways for a short time, after which the Ras/MAPK pathway becomes reactivated. Akt inhibition selectively blocks the transcriptional activation of Ets-1, which inhibits its target gene, dual specificity phosphatase 6 (DUSP6), a negative regulator specific for ERK1/2. As a result, ERK1/2 is activated. Furthermore, elevated c-Src stimulates Ras GTP-loading and activates Raf and MEK kinases. These observations suggest that not only ERK1/2 but also Akt activity is essential to maintain Ets-1 in an active state. Therefore, despite high levels of ERK1/2, Ets-1 target genes including DUSP6 and cyclins D1, D3, and E2 remain suppressed by Akt inhibition. Reduction of DUSP6 in combination with elevated c-Src renews activation of the Ras/MAPK pathway, which enhances cell survival by accelerating Bim protein turnover. Thus, EGFR TKIs evoke innate drug resistance by preventing Akt activity and inactivating Ets-1 function in NSCLC cells.

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AMP-activated protein kinase activation modulates progesterone secretion in granulosa cells from hen preovulatory follicles

Journal of Endocrinology ◽

10.1677/joe.1.06828 ◽

2006 ◽

Vol 190 (1) ◽

pp. 85-97 ◽

Cited By ~ 49

Author(s):

Lucie Tosca ◽

Sabine Crochet ◽

Pascal Ferré ◽

Fabienne Foufelle ◽

Sophie Tesseraud ◽

...

Keyword(s):

Protein Kinase ◽

Granulosa Cells ◽

Cholesterol Metabolism ◽

Specific Inhibitor ◽

Negative Regulator ◽

Star Protein ◽

Theca Cells ◽

Progesterone Secretion ◽

Preovulatory Follicles ◽

Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) is a fuel sensor in glucose, lipid, and cholesterol metabolism. Using RT-PCR and Western blot, AMPK subunits mRNAs (α1/2, β1/2, and γ1/2) and proteins (α1/2 and β1/2) can be found in the hen preovulatory follicles and precisely in both granulosa and theca cells. These preovulatory follicles are organized in a hierarchy according to their size (F5/6 to F1). The smallest number (F1) corresponds to the largest size and the latest mature stage. Phosphorylation of AMPKα on Thr172 and of acetyl-CoA carboxylase on Ser79 are higher in F4 and F3 than in F1 granulosa cells. However, they are not affected in F4–F1 theca cells. Treatment with 1 mM 5-amino-imidazole-4-carboxyamide-1-β-d-ribofuranoside (AICAR), an activator of AMPK, dose dependently increased phosphorylation of AMPKα on Thr172 in primary F3/4 and F1 granulosa cells. In the absence of FSH, AICAR treatment increased progesterone, P450 side chain cleavage and steroidogenic acute regulatory (StAR) production in both F3/4 and F1 granulosa cells. However, in the presence of FSH, AICAR treatment for 36 h increased progesterone secretion, StAR protein levels and reduced extracellular signal-regulated kinase (ERK)1/2 phosphorylation in F3/4 granulosa cells. Opposite data were observed in F1 granulosa cells. Adenovirus-mediated expression of dominant-negative AMPK totally restored the effects of AICAR on FSH-induced progesterone secretion, StAR protein production, and ERK1/2 phosphorylation in F3/4 and F1 granulosa cells. Using a specific inhibitor of ERK1/2 (U0126), we also showed that this kinase is a negative regulator of the FSH-induced progesterone secretion in F3/4 and F1 granulosa cells, suggesting that AICAR-mediated AMPK activation modifies FSH-induced progesterone secretion differently through the ERK1/2 signaling pathway in hen F3/4 and F1 granulosa cells.

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