Altered metabolism is a hallmark of cancer. Malignant cells metabolise glutamine to fulfil their metabolic needs. In prostate cancer, androgen receptor signalling promotes glutamine metabolism, which is also involved in cholesterol homeostasis. We aimed to determine whether the plasma glutamine levels correlate with the blood lipid profile, clinical characteristics and outcomes in patients with metastatic castration resistance prostate cancer (mCRPC) undergoing taxanes. We retrospectively assessed the glutamine and glutamate levels in plasma samples by a bioluminescent assay. Pre-treatment glutamine, glutamate, cholesterol and triglycerides levels were correlated with patients’ clinical characteristics, taxanes response and clinical outcomes. Seventy-five patients with mCRPC treated with taxanes were included. The plasma glutamine levels were significantly higher in patients that received abiraterone or enzalutamide prior to taxanes (p = 0.003). Besides, patients with low glutamine levels were more likely to present a PSA response to taxanes (p = 0.048). Higher glutamine levels were significantly correlated with shorter biochemical/clinical progression-free survival (PSA/RX-PFS) (median 2.5 vs. 4.2 months; p = 0.048) and overall survival (OS) (median 12.6 vs. 20.3; p = 0.008). High cholesterol levels independently predicted early PSA/RX-PFS (p = 0.034). High glutamine and cholesterol in the plasma from patients with mCRPC were associated with adverse clinical outcomes, supporting the relevance of further research on metabolism in prostate cancer progression.

(1) Background: Androgen deprivation therapy (ADT) and docetaxel (DX) combination is a standard therapy for metastatic hormone-sensitive prostate cancer (mHSPC) patients. (2) Methods: We investigate if tumor transcriptomic analysis predicts mHSPC evolution in a multicenter retrospective biomarker study. A customized panel of 184 genes was tested in mRNA from tumor samples by the nCounter platform in 125 mHSPC patients treated with ADT+DX. Gene expression was correlated with castration-resistant prostate cancer-free survival (CRPC-FS) and overall survival (OS). (3) Results: High expression of androgen receptor (AR) signature was independently associated with longer CRPC-FS (hazard ratio (HR) 0.6, 95% confidence interval (CI) 0.3–0.9; p = 0.015), high expression of estrogen receptor (ESR) signature with longer CRPC-FS (HR 0.6, 95% CI 0.4–0.9; p = 0.019) and OS (HR 0.5, 95% CI 0.2–0.9, p = 0.024), and lower expression of tumor suppressor genes (TSG) (RB1, PTEN and TP53) with shorter OS (HR 2, 95% CI 1–3.8; p = 0.044). ARV7 expression was independently associated with shorter CRPC-FS (HR 1.5, 95% CI 1.1–2.1, p = 0.008) and OS (HR 1.8, 95% CI 1.2–2.6, p = 0.004), high ESR2 was associated with longer OS (HR 0.5, 95% CI 0.2–1, p = 0.048) and low expression of RB1 was independently associated with shorter OS (HR 1.9, 95% CI 1.1–3.2, p = 0.014). (4) Conclusions: AR, ESR, and TSG expression signatures, as well as ARV7, RB1, and ESR2 expression, have a prognostic value in mHSPC patients treated with ADT+DX.

Alterations in the PTEN tumor suppressor gene are common in prostate cancer. They have been associated with a more aggressive disease and poor outcomes and potential benefit of targeted therapies. The purpose of this work is to study the clinical and transcriptional landscapes associated to low PTEN mRNA expression in metastatic hormone-sensitive prostate cancer (mHSPC) patients. A multicenter biomarker ambispective study was performed in mHSPC patients. PTEN mRNA expression was assessed by nCounter in formalin-fixed paraffin-embedded tumor samples. PTEN_low status was defined by a previously validated cut-off and was correlated with castration-resistant prostate cancer (CRPC)-free survival (CRPC-FS) (primary endpoint) and overall survival (OS). RNA-Seq was performed to molecularly characterize PTEN_low vs. PTEN_wt tumors. A total of 380 patients were included, 350 eligible. PTEN_low was observed in 28.2% of patients and was independently associated with shorter CRPC-FS (HR 1.6, 95% CI 1.2–2.1, p = 0.002) and OS (HR 1.5, 95% CI 1.1–2, p = 0.014). PTEN_low tumors showed overexpression of neuroendocrine, cell cycle, and DNA repair gene signatures, reduced expression of the androgen receptor pathway, and a distinct immune microenvironment. Using microarray data from the CHAARTED trial, we developed a PTEN-low related signature, independently associated with CRPC-FS (HR 1.5, 95% CI 1–2.3, p = 0.036) and OS (HR 1.9, C1 1.2–2.9, p = 0.005), and identified targets for potential therapies in PTEN-altered tumors. We conclude that PTEN_low correlates with an aggressive clinical outcome in mHSPC patients and is associated with a unique transcriptional profile. These findings further support the investigation of novel therapeutic strategies for patients with PTEN alterations.