A glutaminase isoform switch drives therapeutic resistance and disease progression of prostate cancer
Menée in vitro et à l'aide de modèles murins de cancer de la prostate, cette étude met en évidence un mécanisme par lequel l'expression d'une isoforme de la glutaminase 1 favorise la résistance thérapeutique et la progression de la maladie
We report that androgen receptor (AR) promotes glutaminase 1 (GLS1) expression and glutamine utilization to support the survival of prostate cancer (PCa) cells. Hormonal therapy inhibits AR and decreases GLS1 expression and glutamine utilization to achieve therapeutic effect. Our results suggest that eventually the tumor cells switch GLS1 expression from the AR-dependent KGA isoform to the androgen-independent and enzymatically more potent GAC isoform, which increases glutamine utilization and can contribute to the development of castration-resistant PCa. Our work has discovered a previously unknown AR function, a metabolic mechanism of hormonal therapy and an important therapeutic target more specific than AR. Targeting GLS1 may achieve similar therapeutic efficacy but without the side effects resulting from inhibiting AR’s other important physiologic functions.Cellular metabolism in cancer is significantly altered to support the uncontrolled tumor growth. How metabolic alterations contribute to hormonal therapy resistance and disease progression in prostate cancer (PCa) remains poorly understood. Here we report a glutaminase isoform switch mechanism that mediates the initial therapeutic effect but eventual failure of hormonal therapy of PCa. Androgen deprivation therapy inhibits the expression of kidney-type glutaminase (KGA), a splicing isoform of glutaminase 1 (GLS1) up-regulated by androgen receptor (AR), to achieve therapeutic effect by suppressing glutaminolysis. Eventually the tumor cells switch to the expression of glutaminase C (GAC), an androgen-independent GLS1 isoform with more potent enzymatic activity, under the androgen-deprived condition. This switch leads to increased glutamine utilization, hyperproliferation, and aggressive behavior of tumor cells. Pharmacological inhibition or RNA interference of GAC shows better treatment effect for castration-resistant PCa than for hormone-sensitive PCa in vitro and in vivo. In summary, we have identified a metabolic function of AR action in PCa and discovered that the GLS1 isoform switch is one of the key mechanisms in therapeutic resistance and disease progression.All study data are included in the article and/or supporting information.