BRAFV600E mutations occur in ∼10% of colorectal cancer cases, are associated with poor survival, and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT colorectal cancer. We have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n = 31; validation set: n = 26) colorectal cancer, and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome. These analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT colorectal cancer subgroup with poorest outcome. We also found that oncogenic BRAF drives endoplasmic reticulum (ER) stress and UPR pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT colorectal cancer cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis, and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression. Taken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT colorectal cancer. Mol Cancer Ther; 17(6); 1280-90. ©2018 AACR.

• MeSH
• apoptóza účinky léků   genetika   MeSH
• biologické modely MeSH
• chaperon endoplazmatického retikula BiP MeSH
• inhibitory proteinkinas farmakologie   MeSH
• kolorektální nádory farmakoterapie   genetika   metabolismus   mortalita   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém MeSH
• mutace * MeSH
• nádorové biomarkery MeSH
• nádorové buněčné linie MeSH
• oligopeptidy farmakologie   MeSH
• prognóza MeSH
• proteiny teplotního šoku genetika   metabolismus   MeSH
• proteosyntéza MeSH
• protinádorové látky farmakologie   MeSH
• protoonkogenní proteiny B-Raf antagonisté a inhibitory   genetika   metabolismus   MeSH
• pyrimidiny farmakologie   MeSH
• signální dráha UPR účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• stres endoplazmatického retikula účinky léků   genetika   MeSH
• transkripční faktor CHOP genetika   metabolismus   MeSH
• viabilita buněk účinky léků   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• carfilzomib MeSH Prohlížeč
• chaperon endoplazmatického retikula BiP MeSH
• DDIT3 protein, human MeSH Prohlížeč
• HSPA5 protein, human MeSH Prohlížeč
• inhibitory proteinkinas MeSH
• kyseliny hydroxamové MeSH
• nádorové biomarkery MeSH
• oligopeptidy MeSH
• proteiny teplotního šoku MeSH
• protinádorové látky MeSH
• protoonkogenní proteiny B-Raf MeSH
• pyrimidiny MeSH
• ricolinostat MeSH Prohlížeč
• transkripční faktor CHOP MeSH

Neuroblastoma is the most common extracranial solid tumour of infancy. Pathological activation of glucose consumption, glycolysis and glycolysis-activating Akt kinase occur frequently in neuroblastoma cells, and these changes correlate with poor prognosis of patients. Therefore, several inhibitors of glucose utilization and the Akt kinase activity are in preclinical trials as potential anti-cancer drugs. However, metabolic plasticity of cancer cells might undermine efficacy of this approach. In this work, we identified oxidative phosphorylation as compensatory mechanism preserving viability of neuroblastoma cells with inhibited glucose uptake/Akt kinase. It was oxidative phosphorylation that maintained intracellular level of ATP and proliferative capacity of these cells. The oxidative phosphorylation inhibitors (rotenone, tetrathiomolybdate) synergized with inhibitor of the Akt kinase/glucose uptake in down-regulation of both viability of neuroblastoma cells and clonogenic potential of cells forming neuroblastoma spheroids. Interestingly, tetrathiomolybdate acted as highly specific inhibitor of oxygen consumption and activator of lactate production in neuroblastoma cells, but not in normal fibroblasts and neuronal cells. Moreover, the reducing effect of tetrathiomolybdate on cell viability and the level of ATP in the cells with inhibited Akt kinase/glucose uptake was also selective for neuroblastoma cells. Therefore, efficient elimination of neuroblastoma cells requires inhibition of both glucose uptake/Akt kinase and oxidative phosphorylation activities. The use of tetrathiomolybdate as a mitochondrial inhibitor contributes to selectivity of this combined treatment, preferentially targeting neuroblastoma cells.

• Klíčová slova
• Akt kinase, cell viability, glycolysis, metabolic plasticity, neuroblastoma, oxygen consumption, tetrathiomolybdate,
• MeSH
• adenosintrifosfát metabolismus   MeSH
• buněčné dýchání účinky léků   MeSH
• down regulace účinky léků   MeSH
• fibroblasty účinky léků   metabolismus   MeSH
• fosforylace účinky léků   MeSH
• glukosa metabolismus   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• kyselina mléčná biosyntéza   MeSH
• lidé MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• molybden farmakologie   MeSH
• myši inbrední C57BL MeSH
• nádorové buněčné linie MeSH
• neuroblastom enzymologie   metabolismus   patologie   MeSH
• neurony účinky léků   metabolismus   MeSH
• oxidativní fosforylace účinky léků   MeSH
• protoonkogenní proteiny c-akt antagonisté a inhibitory   metabolismus   MeSH
• spotřeba kyslíku účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfát MeSH
• glukosa MeSH
• inhibitory proteinkinas MeSH
• kyselina mléčná MeSH
• molybden MeSH
• protoonkogenní proteiny c-akt MeSH
• tetrathiomolybdate MeSH Prohlížeč

Nutrient availability controls the landscape of nutrient transporters present at the plasma membrane, notably by regulating their ubiquitylation and subsequent endocytosis. In yeast, this involves the Nedd4 ubiquitin ligase Rsp5 and arrestin-related trafficking adaptors (ARTs). ARTs are targeted by signaling pathways and warrant that cargo ubiquitylation and endocytosis appropriately respond to nutritional inputs. Here, we show that glucose deprivation regulates the ART protein Csr2/Art8 at multiple levels to trigger high-affinity glucose transporter endocytosis. Csr2 is transcriptionally induced in these conditions through the AMPK orthologue Snf1 and downstream transcriptional repressors. Upon synthesis, Csr2 becomes activated by ubiquitylation. In contrast, glucose replenishment induces CSR2 transcriptional shutdown and switches Csr2 to an inactive, deubiquitylated form. This glucose-induced deubiquitylation of Csr2 correlates with its phospho-dependent association with 14-3-3 proteins and involves protein kinase A. Thus, two glucose signaling pathways converge onto Csr2 to regulate hexose transporter endocytosis by glucose availability. These data illustrate novel mechanisms by which nutrients modulate ART activity and endocytosis.

• MeSH
• arrestin genetika   metabolismus   MeSH
• časové faktory MeSH
• endocytóza * MeSH
• genetická transkripce MeSH
• glukosa nedostatek   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• mutace MeSH
• protein-serin-threoninkinasy metabolismus   MeSH
• proteinfosfatasa 1 metabolismus   MeSH
• proteinkinasy závislé na cyklickém AMP metabolismus   MeSH
• proteiny 14-3-3 metabolismus   MeSH
• proteiny přenášející monosacharidy genetika   metabolismus   MeSH
• regulace genové exprese u hub MeSH
• represorové proteiny metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• ubikvitinace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arrestin MeSH
• BMH1 protein, S cerevisiae MeSH Prohlížeč
• BMH2 protein, S cerevisiae MeSH Prohlížeč
• Csr2 protein, S cerevisiae MeSH Prohlížeč
• glukosa MeSH
• Hxt6 protein, S cerevisiae MeSH Prohlížeč
• HXT7 protein, S cerevisiae MeSH Prohlížeč
• jaderné proteiny MeSH
• MIG1 protein, S cerevisiae MeSH Prohlížeč
• Mig2 protein, S cerevisiae MeSH Prohlížeč
• protein-serin-threoninkinasy MeSH
• proteinfosfatasa 1 MeSH
• proteinkinasy závislé na cyklickém AMP MeSH
• proteiny 14-3-3 MeSH
• proteiny přenášející monosacharidy MeSH
• represorové proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• SNF1-related protein kinases MeSH Prohlížeč

Effective treatment options for advanced colorectal cancer (CRC) are limited, survival rates are poor and this disease continues to be a leading cause of cancer-related deaths worldwide. Despite being a highly heterogeneous disease, a large subset of individuals with sporadic CRC typically harbor relatively few established 'driver' lesions. Here, we describe a collection of genetically engineered mouse models (GEMMs) of sporadic CRC that combine lesions frequently altered in human patients, including well-characterized tumor suppressors and activators of MAPK signaling. Primary tumors from these models were profiled, and individual GEMM tumors segregated into groups based on their genotypes. Unique allelic and genotypic expression signatures were generated from these GEMMs and applied to clinically annotated human CRC patient samples. We provide evidence that a Kras signature derived from these GEMMs is capable of distinguishing human tumors harboring KRAS mutation, and tracks with poor prognosis in two independent human patient cohorts. Furthermore, the analysis of a panel of human CRC cell lines suggests that high expression of the GEMM Kras signature correlates with sensitivity to targeted pathway inhibitors. Together, these findings implicate GEMMs as powerful preclinical tools with the capacity to recapitulate relevant human disease biology, and support the use of genetic signatures generated in these models to facilitate future drug discovery and validation efforts.

• Klíčová slova
• BRAF, Colorectal cancer, GEMM, Genomic signatures, KRAS, MAPK,
• MeSH
• alely MeSH
• druhová specificita MeSH
• geny ras MeSH
• kolorektální nádory enzymologie   genetika   patologie   MeSH
• lidé MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• protoonkogenní proteiny B-Raf genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BRAF protein, human MeSH Prohlížeč
• mitogenem aktivované proteinkinasy MeSH
• protoonkogenní proteiny B-Raf MeSH