Presenilin-1 (PS1), the main component of γ-secretase activity support a key role during Epithelial- Mesenchymal Transition (EMT) and chemoresistance acquisition by triggering a complex sequence of molecular events, including E-cadherin down-regulation. However, we hypothesize that EMT and chemoresistance should be deemed separate processes in HCT-8 colon cancer cells. Main methods: HCT-8 and HCT-8FUres invasion was evaluated by trans-well assay. uPA activity was detected by zymography. Prostaglandin E2 levelswere quantified using an ELISA kit. E-cadherin FL and CTF2, PS1,Notch1, Cyclin D1, COX2, SNAI1 and α-SMA expression were determined using Western blot technique. β-Catenin localization was observed by confocal microscopy. Cell apoptosis was evaluated by cytofluorimetric assay, and measurement of caspase-3 and cl-PARP. γ-Secretase activity was inhibited by DAPT, a γ-secretase inhibitor. Key findings: Chemoresistant HCT-8 underwent EMT that can be efficiently reversed by inhibiting PS1 activity, leading thus to a normalization of mostly of the pivotal features showed by the invasive cancer phenotype. Indeed, we observed decreased SNAI1 and Notch 1 activation, altogether with reduced E-cadherin cleavage. Concomitantly, resistant HCT-8 invasiveness was almost completely abolished. However, such reversion was not followed by any increase in apoptotic rate, not by changes in E-cadherin levels. Indeed, despite HCT-8FUres underwent an undeniable EMT, full-length E-cadherin levels were found remarkably higher than those observed in wild HCT-8. Significance: High E-cadherin concentration in presence of enhanced γ-secretase activity is incontestably a paradoxically result, highlighting that E-cadherin loss is not a pre-requisite for EMT. Additionally, EMT and chemoresistance acquisition in HCT-8 should be considered as distinct processes.

Paradoxical E-cadherin increase in 5FU-resistant colon cancer is unaffected during mesenchymal-epithelial reversion induced by γ-secretase inhibition / Dinicola, Simona; Pasqualato, Alessia; Proietti, Sara; Masiello, Maria Grazia; Palombo, Alessandro; Coluccia, Pierpaolo; Canipari, Rita; Catizone, Angiolina; Ricci, Giulia; Harrath, Abdel Halim; Alwasel, Saleh H.; Cucina, Alessandra; Bizzarri, Mariano. - In: LIFE SCIENCES. - ISSN 0024-3205. - 145:(2016), pp. 174-183. [10.1016/j.lfs.2015.12.048]

Paradoxical E-cadherin increase in 5FU-resistant colon cancer is unaffected during mesenchymal-epithelial reversion induced by γ-secretase inhibition

Coluccia, Pierpaolo;CANIPARI, Rita;CATIZONE, Angiolina;CUCINA, Alessandra;BIZZARRI, Mariano;DINICOLA, SIMONA;PALOMBO, ALESSANDRO;RICCI, GIULIA ANTEA
2016

Abstract

Presenilin-1 (PS1), the main component of γ-secretase activity support a key role during Epithelial- Mesenchymal Transition (EMT) and chemoresistance acquisition by triggering a complex sequence of molecular events, including E-cadherin down-regulation. However, we hypothesize that EMT and chemoresistance should be deemed separate processes in HCT-8 colon cancer cells. Main methods: HCT-8 and HCT-8FUres invasion was evaluated by trans-well assay. uPA activity was detected by zymography. Prostaglandin E2 levelswere quantified using an ELISA kit. E-cadherin FL and CTF2, PS1,Notch1, Cyclin D1, COX2, SNAI1 and α-SMA expression were determined using Western blot technique. β-Catenin localization was observed by confocal microscopy. Cell apoptosis was evaluated by cytofluorimetric assay, and measurement of caspase-3 and cl-PARP. γ-Secretase activity was inhibited by DAPT, a γ-secretase inhibitor. Key findings: Chemoresistant HCT-8 underwent EMT that can be efficiently reversed by inhibiting PS1 activity, leading thus to a normalization of mostly of the pivotal features showed by the invasive cancer phenotype. Indeed, we observed decreased SNAI1 and Notch 1 activation, altogether with reduced E-cadherin cleavage. Concomitantly, resistant HCT-8 invasiveness was almost completely abolished. However, such reversion was not followed by any increase in apoptotic rate, not by changes in E-cadherin levels. Indeed, despite HCT-8FUres underwent an undeniable EMT, full-length E-cadherin levels were found remarkably higher than those observed in wild HCT-8. Significance: High E-cadherin concentration in presence of enhanced γ-secretase activity is incontestably a paradoxically result, highlighting that E-cadherin loss is not a pre-requisite for EMT. Additionally, EMT and chemoresistance acquisition in HCT-8 should be considered as distinct processes.
2016
chemoresistance; E-cadherin; EMT; presenilin-1; SNAI1; γ-Secretase activity; amyloid precursor protein secretases; antimetabolites, antineoplastic; cadherins; cell line, tumor; colon; colonic neoplasms; drug resistance, neoplasm; epithelial-mesenchymal transition; fluorouracil; humans; medicine (all); biochemistry; genetics and molecular biology (all); pharmacology; toxicology and pharmaceutics (all)
01 Pubblicazione su rivista::01a Articolo in rivista
Paradoxical E-cadherin increase in 5FU-resistant colon cancer is unaffected during mesenchymal-epithelial reversion induced by γ-secretase inhibition / Dinicola, Simona; Pasqualato, Alessia; Proietti, Sara; Masiello, Maria Grazia; Palombo, Alessandro; Coluccia, Pierpaolo; Canipari, Rita; Catizone, Angiolina; Ricci, Giulia; Harrath, Abdel Halim; Alwasel, Saleh H.; Cucina, Alessandra; Bizzarri, Mariano. - In: LIFE SCIENCES. - ISSN 0024-3205. - 145:(2016), pp. 174-183. [10.1016/j.lfs.2015.12.048]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/902725
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