Clinicopathologic and genomic characterizations of CRPC tumors lead to subdividing CRPC into two subtypes: (1) AR-dependent CRPC containing dysregulation of AR signaling alterations in AR such as amplification, point mutations, and/or generation of splice variants in the AR gene; and (2) an aggressive variant PCa (AVPC) subtype that is phenotypically similar to small cell prostate cancer and is defined by chemotherapy sensitivity, gain of neuroendocrine or pro-neural marker expression, loss of AR expression, and combined alterations of PTEN, TP53, and RB1 tumor suppressors.
In this review, we will discuss the switches between different cell fates that occur in response to AR blockade or acquisition of specific oncogenic mutations, such as those in TP53 and RB1, during the evolution to CRPC.
We tested whether tissue-based analysis of p53 and PTEN genomic status in primary tumors is predictive for subsequent sensitivity to abiraterone and enzalutamide in castration-resistant prostate cancer (CRPC).
Beyond the tumor suppressor TP53, the POLR2A gene encoding the catalytic subunit of RNA polymerase II (RNAP2) is also included in a ~20-megabase deletion region of 17p in 63% of metastatic castration-resistant prostate cancer (CRPC).
To investigate the effect of gambogic acid (GA) on the growth and cell death of castrate resistant prostate cancer (PC) with phosphate and tension homology (PTEN) and p53 genes deleted in vitro and ex vivo, and elucidate the underlying possible molecular mechanisms.
Most importantly, a concurrent elevation of Skp2 and Ezh2 was found in CRPC tumors of Pten/Trp53 mutant mice, and expression levels of SKP2 and EZH2 were positively correlated in human PCa specimens.
Mutations in the p53 tumor suppressor are frequent in patients with castration-resistant prostate cancer but less so in patients with localized disease, and patients who have Li-Fraumeni with germline p53 mutations do not have an increased incidence of prostate cancer, suggesting that additional molecular and/or genetic changes are required for p53 to promote prostate carcinogenesis.
Here we report that co-deletion of Pten and p53 in murine prostate epithelium, often observed in human CRPC, leads to AR-independent CRPC and thus confers de novo resistance to second generation androgen deprivation therapy (ADT) in multiple independent yet complementary preclinical mouse models.
Of significance, castration-resistant prostate cancer (CRPC) C4-2 cells show a much more robust response to the combination treatment than the parental androgen-dependent prostate cancer LNCaP cells, indicating that targeting energy metabolism with metformin plus p53 stabilizers might be a valid approach to treat CRPC carrying WT p53.
Conversely, this response is bypassed with deletion of either Trp53 or Zbtb7a together with Pten, leading to the development of castration-resistant prostate cancer (CRPC).
While such agents have undergone extensive study in many solid tumor types, the additional importance of Rb and p53 in restraining transcription of the AR gene within the prostate provides impetus for examining how loss of these two tumor suppressor proteins can facilitate transition of prostate cancers to CRPC.
The androgen receptor (AR) is known to play a critical role in prostate cancer (PC). p53 likely also plays a role given that p53 mutations are commonly found in advanced PC, and loss of wild-type protein function contributes to the phenotype of castration-resistant prostate cancer (CRPC).
The overwhelming bulk of evidence suggests that the frequency of p53 abnormalities does increase with disease progression and is highest in tissues from patients with hormone-refractory prostate cancer.