Title: A Targetable GATA2-IGF2 Axis Confers Aggressiveness in Chemotherapy Resistant Prostate Cancer
Description: Prostate cancer is a common malignancy with nearly one million annual diagnoses worldwide. Among a subset of patients, primary disease eventually progresses to disseminated castration resistant prostate cancer (CRPC). In recent years, treatment modalities that improve survival in CRPC have emerged including taxane chemotherapy and second generation androgen signaling inhibitors, among others. Indeed, today the first line chemotherapeutic docetaxel as well as the second line agent cabazitaxel are mainstays of treatment. However, CRPC inexorably progresses to a chemotherapy resistant state that ultimately precedes lethality. Elucidating the molecular determinants of aggressiveness in chemotherapy resistant CRPC may therefore stimulate new therapeutic strategies that improve clinical outcomes. We used laboratory models and clinical databases to identify GATA2 as a regulator of chemotherapy resistance and tumorigenicity in this context. Whole genome expression profiling, clinical validation and genetic screening approaches revealed that GATA2 regulates a signature of cancer progression associated genes.

Mechanistically, direct upregulation of the growth hormone IGF2 emerged as a significant mediator of the aggressive properties regulated by GATA2. IGF2 in turn activated IGF1R and INSR as well as a downstream polykinase program. The characterization of this regulatory axis prompted a combination strategy whereby dual IGF1R/INSR inhibition restored the efficacy of chemotherapy and improved survival in preclinical models. These studies reveal a GATA2-IGF2 aggressiveness axis in chemotherapy resistant prostate cancer and identify a therapeutic opportunity in this challenging disease.