Androgen Receptor-independent Prostate Cancer Research Articles

SIX2 promotes cell plasticity via Wnt/β-catenin signalling in androgen receptor independent prostate cancer.

The use of androgen receptor (AR) inhibitors in prostate cancer gives rise to increased cellular lineage plasticity resulting in resistance to AR-targeted therapies. In this study, we examined the chromatin landscape of AR-positive prostate cancer cells post-exposure to the AR inhibitor enzalutamide. We identified a novel regulator of cell plasticity, the homeobox transcription factor SIX2, whose motif is enriched in accessible chromatin regions after treatment. Depletion of SIX2 in androgen-independent PC-3 prostate cancer cells induced a switch from a stem-like to an epithelial state, resulting in reduced cancer-related properties such as proliferation, colony formation, and metastasis both in vitro and in vivo. These effects were mediated through the downregulation of the Wnt/β-catenin signalling pathway and subsequent reduction of nuclear β-catenin. Collectively, our findings provide compelling evidence that the depletion of SIX2 may represent a promising strategy for overcoming the cell plasticity mechanisms driving antiandrogen resistance in prostate cancer.

P04 - SIX2 promotes cell plasticity via Wnt/ß-catenin signalling in androgen receptor independent prostate cancer

P04 - SIX2 promotes cell plasticity via Wnt/ß-catenin signalling in androgen receptor independent prostate cancer

Abstract A068: Prostate luminal progenitors as the cell-of-origin for androgen receptor-independent prostate cancer

Abstract In the recent years, we have witnessed the emergence of androgen receptor (AR)-independent prostate cancer (AIPC) with the clinical use of second-generation androgen deprivation therapy, namely Enzalutamide and Abiraterone. Unluckily, treatment options for the end-stage AIPC patients are mainly palliative but not curable. However, the cellular origin and mechanisms involved in the evolution of AIPCs remain unclear. Previously, we have discovered that AR is not required for the survival and maintenance of progenitor property of CA stration- R esistant N kx3.1-expressing cells (CARNs), thus highlighting the AR-independent nature of this luminal progenitor subset. Interestingly, AR-deleted CARNs demonstrate gene expression profile that is highly similar to human neuroendocrine prostate cancer (NEPC), a subtype of AIPC. Moreover, upon Pten deletion and mutated Kras activation, AR-deleted CARNs can generate tumors exhibiting focal neuroendocrine differentiation, indicating the ability of CARNs to serve as a cell-of-origin for NEPC. Based on these observations, we hypothesize that AR-independent prostate luminal progenitor subsets are capable of initiating AIPC upon oncogenic transformation, while the transformed cells represent distinct subsets in AIPC that possess cancer stem cell property. In our latest assessments, we have validated the ability of CARNs to initiate NEPC using a novel genetically-engineered mouse model of prostate cancer. Moreover, we have established tumor organoids from CARNs-initiated AIPC, which are capable of generating allografts in both immunodeficient and immunocompetent mice, implying their immune-evading capability. Lastly, we have performed small molecule library screening on the transformed CARNs-derived tumor organoids to identify effective treatment options for AIPC. Taken together, our study has provided novel insights into the cellular origin of AIPCs. Consequently, targeting these prostate luminal progenitors-initiated tumor cells as well as their molecular property may serve as novel therapeutic strategies to overcome AR independence in prostate cancer. Citation Format: Chee Wai Chua. Prostate luminal progenitors as the cell-of-origin for androgen receptor-independent prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A068.

The Crosstalk of Long Non-Coding RNA and MicroRNA in Castration-Resistant and Neuroendocrine Prostate Cancer: Their Interaction and Clinical Importance.

Prostate cancer is featured by its heterogeneous nature, which indicates a different prognosis. Castration-resistant prostate cancer (CRPC) is a hallmark of the treatment-refractory stage, and the median survival of patients is only within two years. Neuroendocrine prostate cancer (NEPC) is an aggressive variant that arises from de novo presentation of small cell carcinoma or treatment-related transformation with a median survival of 1–2 years from the time of diagnosis. The epigenetic regulators, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), have been proven involved in multiple pathologic mechanisms of CRPC and NEPC. LncRNAs can act as competing endogenous RNAs to sponge miRNAs that would inhibit the expression of their targets. After that, miRNAs interact with the 3’ untranslated region (UTR) of target mRNAs to repress the step of translation. These interactions may modulate gene expression and influence cancer development and progression. Otherwise, epigenetic regulators and genetic mutation also promote neuroendocrine differentiation and cancer stem-like cell formation. This step may induce neuroendocrine prostate cancer development. This review aims to provide an integrated, synthesized overview under current evidence to elucidate the crosstalk of lncRNAs with miRNAs and their influence on castration resistance or neuroendocrine differentiation of prostate cancer. Notably, we also discuss the mechanisms of lncRNA–miRNA interaction in androgen receptor-independent prostate cancer, such as growth factors, oncogenic signaling pathways, cell cycle dysregulation, and cytokines or other transmembrane proteins. Conclusively, we underscore the potential of these communications as potential therapeutic targets in the future.

α-Trifluoromethyl Chalcones as Potent Anticancer Agents for Androgen Receptor-Independent Prostate Cancer.

α-Trifluoromethyl chalcones were prepared and evaluated for their antiproliferative activities against androgen-independent prostate cancer cell lines as well as five additional types of human tumor cell lines. The most potent chalcone 5 showed superior antitumor activity in vivo with both oral and intraperitoneal administration at 3 mg/kg. Cell-based mechanism of action studies demonstrated that 5 induced cell accumulation at sub-G1 and G2/M phases without interfering with microtubule polymerization. Furthermore, several cancer cell growth-related proteins were identified by using chalcone 5 as a bait for the affinity purification of binding proteins.

Cold atmospheric plasma selectively induces G0/G1 cell cycle arrest and apoptosis in AR-independent prostate cancer cells.

Purpose: Androgen receptor-independent prostate cancers do not respond to androgen blockage therapies and suffer from high recurrence rate. We aim to contribute to the establishment of novel therapeutic approaches against such malignancies.Materials and Methods: We examined whether and how cold atmospheric plasma delivers selectivity against AR-independent prostate cancers via cell viability, transwell assay, wound healing, cell apoptosis assay, flow cytometry, intracellular hydrogen peroxide determination assay, RONS scavenger assay and western blot using human normal epithelial prostatic cells PNT1A and AR-negative DU145 prostate cancer cells.Results: We show that cold atmospheric plasma could selectively halt cell proliferation and migration in androgen receptor-independent cells as a result of induced cell apoptosis and G0/G1 stage cell cycle arrest, and such outcomes were achieved through modulations on the MAPK and NF-kB pathways in response to physical plasma induced intracellular redox level.Conclusion: Our study reports cold atmospheric plasma induced reduction on the proliferation and migration of androgen receptor-independent prostate cancer cells that offers novel therapeutic insights on the treatment of such cancers, and provides the first evidence on physical plasma induced cell cycle G0/G1 stage arrest that warrants the exploration on the synergistic use of cold atmospheric plasma and drugs such as chemotherapies in eradicating such cancer cells.

A miR-194-regulated transcriptional network is associated with progression to androgen receptor-independent prostate cancer

Searchable abstracts of presentations at key conferences in oncology ISSN 2631-4657 (online)

Androgen receptor-independent prostate cancer: an emerging clinical entity

ABSTRACTAndrogen deprivation therapy remains the backbone of prostate cancer treatment given its pivotal role in the pathogenesis of prostate cancer. The growing knowledge of androgen receptor-independent (i.e. AR-null) prostate cancer cells, however, might advance the treatment paradigm of prostate cancer. Here, we examined the results of two recent studies, published in Cancer Cell by Bluemn and Shukla et al., and their impact in the future management of castration-resistant prostate cancer.

Knockdown of AKR1C3 exposes a potential epigenetic susceptibility in prostate cancer cells

BackgroundThe aldo-keto reductase 1C3 (AKR1C3) has been heavily implicated in the propagation of prostate malignancy. AKR1C3 protein is elevated within prostate cancer tissue, it contributes to the formation of androgens and downstream stimulation of the androgen receptor (AR). Elevated expression of AKR1C3 is also reported in acute myeloid leukemia but the target nuclear receptors have been identified as members of the peroxisome-proliferator activated receptor (PPARs) subfamily. Thus, AKR1C3 cancer biology is likely to be tissue dependent and hormonally linked to the availability of ligands for both the steroidogenic and non-steroidogenic nuclear receptors. MethodsIn the current study we investigated the potential for AKR1C3 to regulate the availability of prostaglandin-derived ligands for PPARg mainly, prostaglandin J2 (PGJ2). Using prostate cancer cell lines with stably reduced AKR1C3 levels we examined the impact of AKR1C3 upon proliferation mediated by PPAR ligands. ResultsThese studies revealed knockdown of AKR1C3 had no effect upon the sensitivity of androgen receptor independent prostate cancer cells towards PPAR ligands. However, the reduction of levels of AKR1C3 was accompanied by a significantly reduced mRNA expression of a range of HDACs, transcriptional co-regulators, and increased sensitivity towards SAHA, a clinically approved histone deacetylase inhibitor. ConclusionsThese results suggest a hitherto unidentified link between AKR1C3 levels and the epigenetic status in prostate cancer cells. This raises an interesting possibility of a novel rational to target AKR1C3, the utilization of AKRIC3 selective inhibitors in combination with HDAC inhibition as part of novel epigenetic therapies in androgen deprivation therapy recurrent prostate cancer.