Negative prognostic value of high levels of intracellular poly (ADP-ribose) in non-small cell lung cancer
A partir d'échantillons tumoraux prélevés sur une cohorte initiale de 92 patients atteints d'un cancer du poumon non à petites cellules de stade I, puis validée sur une cohorte complémentaire de 133 patients, cette étude évalue l'association entre les niveaux d'expression de PAR et PDXK et le pronostic de la maladie
Background : Cisplatin-resistant non-small cell lung cancer (NSCLC) cells are often characterized by alterations in vitamin B-related metabolic processes, including the overexpression and hyperactivation of poly(ADP-ribose) polymerase 1 (PARP1) and the down-regulation of pyridoxal kinase (PDXK), correlating with elevated apoptosis resistance. Low PDXK expression is an established negative prognostic factor in NSCLC.
Patients and methods : We determined by immunohistochemistry the expression of PARP1 and the level of its product, poly(ADP-ribose) (PAR) in two independent cohorts of patients with resected NSCLC.
Results : Intratumoral high levels (above median) of PAR (but not PARP1 protein levels) had a negative prognostic impact in both the training (92 stage I subjects) and validation (133 stage I and II subjects) cohorts, as determined by univariate and multivariate analyses. The simultaneous assessment of PAR and PDXK protein levels improved risk stratification.
Conclusion : NSCLC patients with high intratumoral PARP1 activity (i.e., elevated PAR levels above median) and low PDXK expression (below median) had, a dismal prognosis, while patients with low PARP1 activity and high PDXK expression had a favourable outcome. Altogether, these results underscore the clinical potential and possible therapeutic relevance of these biomarkers.
Annals of Oncology , résumé, 2015