Evaluation of JQ1 Combined With Docetaxel for the Treatment of Prostate Cancer Cells in 2D- and 3D-Culture Systems

Pan-cancer analysis of prognostic and immunological role of IL4I1 in human tumors: a bulk omics research and single cell sequencing validation

BACKGROUND

Interleukin-4 inducible gene 1 (IL4I1) regulates tumor progression in numerous tumor types. However, its correlation with immune infiltration and prognosis of patients in a pan-cancer setting remains unclear.

METHODS

Data from the Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), UALCAN, Clinical Proteomic Tumor Analysis Consortium (CPTAC), Gene Expression Omnibus (GEO), cBioPortal, Cancer Single-cell State Atlas (CancerSEA), and Tumor IMmune Estimation Resource(TIMER) databases were used to evaluate IL4I1 expression, clinical features and prognostic effects, gene set enrichment, and correlation with immune cell infiltration, as well as the relationship between IL4I1 methylation and expression and survival prognosis. Correlations with 192 anticancer drugs were also analyzed.

RESULTS

IL4I1 was significantly overexpressed in the majority of tumors, and the imbalance of IL4I1 was significantly correlated with overall survival and pathological stage. Moreover, total IL4I1 protein was increased in cancer. Therefore, IL4I1 may be used as a prognostic biomarker or protective factor in numerous types of cancer. The methylation level of IL4I1 may also be used as a prognostic marker. The functional enrichment of IL4I1 was closely related to the immunomodulatory pathway. In addition, the level of tumor-associated macrophage infiltration was positively correlated with the expression of IL4I1 in pan-cancerous tissues. scRNA-seq analysis suggested that IL4I1 differ significantly among different cells in the tumor microenvironment and was most enriched in macrophages. Various immune checkpoint genes were positively correlated with IL4I1 expression in most tumors. In addition, patients with high IL4I1 expression may be resistant to BMS-754807 and docetaxel, but sensitive to temozolomide.

CONCLUSION

IL4I1 may play a role as promoter of cancer and prognostic indicator in patients. High expression of IL4I1 is associated with the state of tumor immunosuppression and may contribute to tumor-associated macrophage invasion. Therefore, IL4I1 may be a new therapeutic target for the treatment and prognosis of patients with cancer.

Effects of docetaxel on metastatic prostate (DU-145) carcinoma cells cultured as 2D monolayers and 3D multicellular tumor spheroids

Docetaxel (DTX) is one of the chemotherapeutic drugs indicated as a first-line treatment against metastatic prostate cancer (mPCa). This study aimed to compare the impact of DTX on mPCa (DU-145) tumor cells cultured as 2D monolayers and 3D multicellular tumor spheroids (MCTS) in vitro. The cells were treated with DTX (1-96 µM) at 24, 48, or 72 hr in cell viability assays (resazurin, phosphatase acid, and lactate dehydrogenase). Cell death was assessed with fluorescent markers and proliferation by clonogenic assay (2D) and morphology, volume, and integrity assay (3D). The cell invasion was determined using transwell (2D) and extracellular matrix (ECM) (3D). Results showed that DTX decreased cell viability in both culture models. In 2D, the IC50 (72 hr) values were 11.06 μM and 14.23 μM for resazurin and phosphatase assays, respectively. In MCTS, the IC50 values for the same assays were 114.9 μM and 163.7 μM, approximately 10-fold higher than in the 2D model. The % of viable cells decreased, while the apoptotic cell number was elevated compared to the control in 2D. In 3D spheroids, only DTX 24 μM induced apoptosis. DTX (≥24 μM at 216 hr) lowered the volume, and DTX 96 μM completely disintegrated the MCTS. DTX reduced the invasion of mPCa cells to matrigel (2D) and migration from MCTS to the ECM. Data demonstrated significant differences in drug response between 2D and 3D cell culture models using mPCa DU-145 tumor cells. MCTS resembles the early stages of solid tumors in vivo and needs to be considered in conjunction with 2D cultures when searching for new therapeutic targets.

Glucocorticoid Receptor and β-Catenin Interact in Prostate Cancer Cells and Their Co-Inhibition Attenuates Tumorsphere Formation, Stemness, and Docetaxel Resistance

Therapy resistance hinders the efficacy of anti-androgen therapies and taxane-based chemotherapy for advanced prostate cancer (PCa). Glucocorticoid receptor (GR) signaling mediates resistance to androgen receptor signaling inhibitors (ARSI) and has also been recently implicated in PCa resistance to docetaxel (DTX), suggesting a role in therapy cross-resistance. Like GR, β-catenin is upregulated in metastatic and therapy-resistant tumors and is a crucial regulator of cancer stemness and ARSI resistance. β-catenin interacts with AR to promote PCa progression. Given the structural and functional similarities between AR and GR, we hypothesized that β-catenin also interacts with GR to influence PCa stemness and chemoresistance. As expected, we observed that treatment with the glucocorticoid dexamethasone promotednuclear accumulation of GR and active β-catenin in PCa cells. Co-immunoprecipitation studies showed that GR and β-catenin interact in DTX-resistant and DTX-sensitive PCa cells. Pharmacological co-inhibition of GR and β-catenin, using the GR modulator CORT-108297 and the selective β-catenin inhibitor MSAB, enhanced cytotoxicity in DTX-resistant PCa cells grown in adherent and spheroid cultures and decreased CD44+/CD24- cell populations in tumorspheres. These results indicate that GR and β-catenin influence cell survival, stemness, and tumorsphere formation in DTX-resistant cells. Their co-inhibition could be a promising therapeutic strategy to overcome PCa therapy cross-resistance.

Let’s Go 3D! New Generation of Models for Evaluating Drug Response and Resistance in Prostate Cancer

Prostate cancer (PC) is the third most frequently diagnosed cancer worldwide and the second most frequent in men. Several risk factors can contribute to the development of PC, and those include age, family history, and specific genetic mutations. So far, drug testing in PC, as well as in cancer research in general, has been performed on 2D cell cultures. This is mainly because of the vast benefits these models provide, including simplicity and cost effectiveness. However, it is now known that these models are exposed to much higher stiffness; lose physiological extracellular matrix on artificial plastic surfaces; and show changes in differentiation, polarization, and cell–cell communication. This leads to the loss of crucial cellular signaling pathways and changes in cell responses to stimuli when compared to in vivo conditions. Here, we emphasize the importance of a diverse collection of 3D PC models and their benefits over 2D models in drug discovery and screening from the studies done so far, outlining their benefits and limitations. We highlight the differences between the diverse types of 3D models, with the focus on tumor–stroma interactions, cell populations, and extracellular matrix composition, and we summarize various standard and novel therapies tested on 3D models of PC for the purpose of raising awareness of the possibilities for a personalized approach in PC therapy.

Role of bromodomain and extraterminal (BET) proteins in prostate cancer

INTRODUCTION

The bromodomain and extraterminal (BET) family of proteins are epigenetic readers of acetylated histones and are critical activators of oncogenic networks across many cancers. Therapeutic targeting of BET proteins has been an attractive area of clinical development for metastatic castration-resistant prostate cancer. In recent years, many structurally diverse BET inhibitors have been discovered and tested. Preclinical studies have demonstrated significant antiproliferative activity of BET inhibitors against prostate cancer. However, their clinical success as monotherapies has been limited by treatment-associated toxicities, primary and acquired drug resistance, and a lack of predictive biomarkers of benefit.

AREAS COVERED

This review provides an overview of advancements in BET inhibitor design, preclinical research, and conclusions from clinical trials in prostate cancer. We speculate on incorporating BET inhibitors into combination regimens with other agents to improve the therapeutic index of BET inhibition in treating prostate cancer.

EXPERT OPINION

The therapeutic potential of BET inhibitors for prostate cancer has been demonstrated in preclinical studies. However, further research is needed to identify biomarkers that can predict sensitivity to BET inhibitors and to develop novel, highly selective inhibitors to reduce toxicities. Finally, BET inhibitors are likely to hold the most clinical potential in combination with other agents.