Plasma cell-free DNA-based predictors of response to abiraterone acetate/prednisone and prognostic factors in metastatic castration-resistant prostate cancer
PROSTATE CANCER AND PROSTATIC DISEASES
Authors: Du, Meijun; Tian, Yijun; Tan, Winston; Wang, Liewei; Wang, Liguo; Kilari, Deepak; Huang, Chiang-Ching; Wang, Liang; Kohli, Manish
Abstract
Background The combination of abiraterone acetate and prednisone (AA/P) is used to treat metastatic prostate cancer, but molecular predictors of treatment response are not well elucidated. We evaluated plasma circulating tumor DNA- (ctDNA-) based copy number alterations (CNAs) to determine treatment-related predictive and prognostic biomarkers for metastatic castration-resistant prostate cancer (mCRPC). Methods Serial plasma specimens were prospectively collected from 88 chemotherapy-naive mCRPC patients before and after 12 weeks of AA/P treatment. Sequencing-based CNA analyses were performed on 174 specimens. We evaluated CNA-associated 12-week responses for primary resistance, time to treatment change (TTTC) for secondary resistance, and overall survival for prognosis (P < 0.05). Associations with primary resistance were analyzed using the Fisher exact test. Kaplan-Meier survival curves and Cox regression analyses were used to determine the associations of CNAs with acquired resistance and overall survival. Results ctDNA reduced by 3.89% in responders and increased by 0.94% in nonresponders (P = 0.0043). Thirty-one prostate cancer-related genes from whole genome CNAs were tested. AR and AR enhancer amplification were associated with primary resistance (P = 0.0039) and shorter TTTC (P = 0.0003). ZFHX3 deletion and PIK3CA amplification were associated with primary resistance (P = 0.026 and P = 0.017, respectively), shorter TTTC (P = 0.0008 and P = 0.0016, respectively), and poor survival (P = 0.0025 and P = 0.0022, respectively). CNA-based risk scores combining selected significant associations (AR, NKX3.1, and PIK3CA) at the univariate level with TTTC were predictive of secondary resistance (P = 0.0002). and established prognoses for survival based on CNAs in ZFHX3, RB1, PIK3CA, and OPHN1 (P = 0.002). Multigene risk scores were more predictive than individual genes or clinical risk factors (P < 0.05). Conclusion Plasma ctDNA CNAs and risk scores can predict mCRPC-state treatment and survival outcomes.
Long-standing arterial hypertension is associated with Pitx2 down-regulation in a rat model of spontaneous atrial tachyarrhythmias
EUROPACE
Authors: Scridon, Alina; Fouilloux-Meugnier, Emmanuelle; Loizon, Emmanuelle; Rome, Sophie; Julien, Claude; Barres, Christian; Chevalier, Philippe
Abstract
Aims The timecourse of left atrial Pitx2 down-regulation in the setting of atrial tachyarrhythmias remains unknown. Accordingly, we aimed to assess the age dependency of left atrial Pitx2 expression in an experimental model of spontaneous atrial tachyarrhythmias in rats. Methods and results Atrial sampling was performed in three groups (n = 4 each) of young (14-week-old), adult (24-week-old), and ageing (48-week-old) spontaneously hypertensive rats (SHRs), in which we previously demonstrated the age dependency of spontaneous atrial tachyarrhythmias, and three groups (n = 4 each) of age-matched normotensive Wistar-Kyoto (WKY) rats. mRNA expression of Pitx2 was studied using real-time polymerase chain reaction. Ageing SHRs presented significantly lower left atrial Pitx2 expressions compared with age-matched WKY rats (P = 0.02), while no significant difference was observed between young or adult SHRs and age-matched WKY rats (both P > 0.05). Among SHRs, Pitx2 expressions showed a progressive, age-dependent decrease (34.9 +/- 6.7 in young SHRs, 17.1 +/- 3.6 in adult SHRs, and 10.7 +/- 1.7 in ageing SHRs, P = 0.04) and were significantly negatively correlated with both age (Spearman r = -0.86, P < 0.01) and heart weight (Spearman r = -0.76, P < 0.01). Conclusion The present study suggests the presence of age-dependent left atrial Pitx2 down-regulation in SHRs. The strong negative correlation between left atrial Pitx2 expression and heart weight among SHRs may indicate a link between long-standing arterial hypertension and Pitx2-related atrial arrhythmogenicity.