biochemical-titration-of-glycogen-in-vitro

Biochemical Titration of Glycogen <em>In vitro</em>

Glycogen is the main energetic polymer of glucose in vertebrate animals and plays a crucial role in whole body metabolism as well as in cellular ...

University of Nice - Sophia Antipolis

The disorganized neo-vasculature in tumours causes fluctuations in the concentration of oxygen, which contributes to tumour development and metastatic potential. Although hypoxic regulation of the expression of the carbonic anhydrases CAIX and CAXII is well established, the effect of re-oxygenation on these proteins remains to be elucidated. A549 and H1975 human lung cancer cell lines were exposed to hypoxia for 24 h and then re-oxygenated. CAIX or CAXII expression and cell cycle progression at different time-points were monitored. A549-shCA9 cells were analyzed for cell cycle progression in the same conditions. We demonstrate for the first time an association between the stability of CAIX and restoration of the S/G2 phase of hypoxia-arrested cells subjected to re-oxygenation. In exchange, we have found that the loss of CA9 did not cause a decreased progression into S/G2 phase during re-oxygenation, but rather affected the hypoxic growth arrest. We previously demonstrated that CAIX expression is a poor prognostic factor and that CAXII expression is a good prognostic factor in non-small cell lung cancer (NSCLC) patients. We further detail the relevance of the combined expression of these proteins for predicting outcome in a large population of NSCLC patients after long-term follow-up. The high CAIX/low CAXII expression sub-group was associated with a high cumulative incidence of relapse and with poor overall survival of NSCLC patients (P < 0.0001). Our results demonstrate a critical role for re-oxygenation on CAIX and CAXII levels that may select for an aggressive lung cancer phenotype. These findings suggest that CAIX and CAXII play dual roles in tumour progression and emphasize their significant prognostic and potential therapeutic value.

Response of CAIX and CAXII to in vitro re-oxygenation and clinical significance of the combined expression in NSCLC patients.

Significance: MicroRNAs (miRNAs) are small non-coding RNAs that have emerged as key regulators of many physiological and pathological processes, including those relevant to hypoxia such as cancer, neurological dysfunctions, myocardial infarction and lung diseases. Recent Advances: During the last five years, microRNAs (miRNAs) have been shown to play a role in the regulation of the cellular response to hypoxia. The identification of several bona fide targets of these hypoxamiRs has underlined their pleiotropic functions and the complexity of the molecular rules directing miRNA::target transcript pairing. Critical Issues: This review outlines the main in silico and experimental approaches used to identify the targetome of hypoxamiRs and presents new recent relevant methodologies for future studies. Future Directions: Since hypoxia plays key roles in many pathophysiological conditions, the precise characterization of regulatory hypoxamiRs networks will be instrumental both at a fundamental level and for their future potential therapeutic applications.

Nathalie M. Mazure

Institute for Research on Cancer and Ageing of Nice,
UMR CNRS 7284 - INSERM,
U1081 - UNS,
Centre Antoine Lacassagne,
Institute for Research on Cancer and Ageing of Nice, UMR CNRS 7284 - INSERM, U1081 - UNS, Centre Antoine Lacassagne

University of Nice - Sophia Antipolis

Biochemical Titration of Glycogen In vitro