Defective ubiquitinylation of EGFR mutants of lung cancer confers prolonged signaling

Shtiegman, Keren; Kochupurakkal, Bose; Zwang, Yaara; Pines, Gur; Starr, Alexander; Vexler, Akiva; Citri, Ami; Katz, Mark N.; Lavi, Sara; Ben-Basat, Y; Benjamin, Sigi; Corso, Simona; Gan, Judith; Yosef, R. Ben; Giordano, Silvia; Yarden, Yosef

doi:10.1038/sj.onc.1210503

Cited by 133 publications

(127 citation statements)

References 30 publications

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“…S1 A). Increased levels of total EGFR protein were also detected; these are likely because of the stabilization of the receptor and reduced degradation imparted by the E746-A750 deletion, as previously shown in lung cancer cells carrying the same allele (15)(16)(17). Interestingly, KRAS, BRAF and PIK3CA mutated cells also displayed allele-specific biochemical features.…”

Section: Ki Of Mutated Braf Egfr Kras and Pik3ca Alleles In The Genmentioning

confidence: 51%

Replacement of normal with mutant alleles in the genome of normal human cells unveils mutation-specific drug responses

Nicolantonio

Arena

Gallicchio

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

124

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Mutations in oncogenes and tumor suppressor genes are responsible for tumorigenesis and represent favored therapeutic targets in oncology. We exploited homologous recombination to knock-in individual cancer mutations in the genome of nontransformed human cells. Sequential introduction of multiple mutations was also achieved, demonstrating the potential of this strategy to construct tumor progression models. Knock-in cells displayed allele-specific activation of signaling pathways and mutation-specific phenotypes different from those obtainable by ectopic oncogene expression. Profiling of a library of pharmacological agents on the mutated cells showed striking sensitivity or resistance phenotypes to pathway-targeted drugs, often matching those of tumor cells carrying equivalent cancer mutations. Thus, knock-in of single or multiple cancer alleles provides a pharmacogenomic platform for the rational design of targeted therapies.cancer mutation ͉ oncogene addiction ͉ pharmacogenomic ͉ targeted therapies ͉ tumor progression model T he construction of model systems that accurately recapitulate the genetic alterations present in human cancer is a prerequisite to understand the cellular properties imparted by the mutated alleles and to identify genotype and tumor-specific pharmacological responses. In this regard, mammalian cell lines have been widely used as model systems to functionally characterize cancer alleles carrying point mutations and to develop and validate anticancer drugs. These models typically involve the ectopic expression (by means of plasmid transfection or viral infection) of mutated cDNAs in human or mouse cells (1). Although these approaches have yielded remarkable results, they are typically hampered by at least two caveats. First, the expression is achieved by transient or stable transfection of cDNAs, often resulting in over-expression of the target allele at levels that do not recapitulate what occurs in human cancers. Second, the expression of the mutated cDNA is achieved under the control of nonendogenous viral promoters. As a result, the mutated alleles cannot be appropriately (endogenously) modulated in the target cells. While such systems in which mutated oncogenes are ectopically expressed under exogenous promoters have been instrumental in dissecting their oncogenic properties, they have also led to controversial results. For example, studies focused on oncogene-mediated transformation and senescence have generated conflicting data depending on whether the cancer alleles were ectopically expressed or permanently introduced in the genome of mouse or human cells (2-5). To address the limitation of current models, we have used targeted homologous recombination to introduce (knock-in, KI) a panel of cancer alleles in human somatic cells. Specifically, we focused on EGFR, KRAS, BRAF, and PIK3CA mutated alleles that are found in multiple cancer types. Mutant cells have then been used to study the biochemical and transforming potential of common cancer alleles and to identify genotype-specific ...

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Section: Ki Of Mutated Braf Egfr Kras and Pik3ca Alleles In The Genmentioning

confidence: 51%

Replacement of normal with mutant alleles in the genome of normal human cells unveils mutation-specific drug responses

Nicolantonio

Arena

Gallicchio

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

124

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“…Cancer cells undergo a marked shift toward aerobic glycolysis (''the Warburg effect'') with coordinate redirecting of glycolytic intermediates from energy production toward anabolic processes (27). EGFRvIII enhanced 18 F-FDG uptake in glioblastoma in vivo, and AICAR treatment coordinately blocked glucose uptake and lipogenesis ( Fig. 5C and D), suggesting that these processes were co-regulated.…”

Section: Discussionmentioning

confidence: 96%

“…To determine whether AICAR treatment inhibited glucose metabolism, after 3 days of treatment, before the significant differences in tumor volumes, mice were imaged by microPET/CT to assess 18 F-2-deoxyglucose ( 18 F-FDG) uptake. EGFRvIII expression led to a highly significant increase in 18 F-FDG uptake at baseline, and AICAR treatment significantly inhibited 18 F-FDG uptake of U87-EGFRvIII expressing tumors in vivo (57% inhibition; P Ͻ 0.01) (Fig. 5C and D).…”

Section: Aicar Blocks the Growth Of Egfrviii-expressing Glioblastomas Inmentioning

confidence: 95%

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The AMPK agonist AICAR inhibits the growth of EGFRvIII-expressing glioblastomas by inhibiting lipogenesis

Guo¹,

Hildebrandt²,

Prins³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

207

224

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The EGFR/PI3K/Akt/mTOR signaling pathway is activated in many cancers including glioblastoma, yet mTOR inhibitors have largely failed to show efficacy in the clinic. Rapamycin promotes feedback activation of Akt in some patients, potentially underlying clinical resistance and raising the need for alternative approaches to block mTOR signaling. AMPK is a metabolic checkpoint that integrates growth factor signaling with cellular metabolism, in part by negatively regulating mTOR. We used pharmacological and genetic approaches to determine whether AMPK activation could block glioblastoma growth and cellular metabolism, and we examined the contribution of EGFR signaling in determining response in vitro and in vivo. The AMPK-agonist AICAR, and activated AMPK adenovirus, inhibited mTOR signaling and blocked the growth of glioblastoma cells expressing the activated EGFR mutant, EGFRvIII. Across a spectrum of EGFR-activated cancer cell lines, AICAR was more effective than rapamycin at blocking tumor cell proliferation, despite less efficient inhibition of mTORC1 signaling. Unexpectedly, addition of the metabolic products of cholesterol and fatty acid synthesis rescued the growth inhibitory effect of AICAR, whereas inhibition of these lipogenic enzymes mimicked AMPK activation, thus demonstrating that AMPK blocked tumor cell proliferation primarily through inhibition of cholesterol and fatty acid synthesis. Most importantly, AICAR treatment in mice significantly inhibited the growth and glycolysis (as measured by 18 fluoro-2-deoxyglucose microPET) of glioblastoma xenografts engineered to express EGFRvIII, but not their parental counterparts. These results suggest a mechanism by which AICAR inhibits the proliferation of EGFRvIII expressing glioblastomas and point toward a potential therapeutic strategy for targeting EGFR-activated cancers.

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“…39 siRNAs targeting Egfr would still be effective in this scenario as the reduction in receptor protein levels would counteract the increased phosphorylation. Likewise, if the receptor ubiquitination and degradation pathways were dysregulated, 40 siRNAs targeting Egfr would still be effective. Regardless of the similar mechanisms were not responsible for the development of resistance in the cell line as no mutations were found in the ATP binding pocket of the receptor when the region was re-sequenced in the resistant cell line.…”

Section: Discussionmentioning

confidence: 99%

Studies on the inhibition of feline EGFR in squamous cell carcinoma: Enhancement of radiosensitivity and rescue of resistance to small molecule inhibitors

Bergkvist¹,

Argyle²,

Pang³

et al. 2011

Cancer Biology & Therapy

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Defective ubiquitinylation of EGFR mutants of lung cancer confers prolonged signaling

Cited by 133 publications

References 30 publications

Replacement of normal with mutant alleles in the genome of normal human cells unveils mutation-specific drug responses

Replacement of normal with mutant alleles in the genome of normal human cells unveils mutation-specific drug responses

The AMPK agonist AICAR inhibits the growth of EGFRvIII-expressing glioblastomas by inhibiting lipogenesis

Studies on the inhibition of feline EGFR in squamous cell carcinoma: Enhancement of radiosensitivity and rescue of resistance to small molecule inhibitors

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