The Molecular Basis and Clinical Consequences of Chronic Inflammation in Prostatic Diseases: Prostatitis, Benign Prostatic Hyperplasia, and Prostate Cancer

Chronic inflammation is now recognized as one of the major risk factors and molecular hallmarks of chronic prostatitis, benign prostatic hyperplasia (BPH), and prostate tumorigenesis. However, the molecular mechanisms by which chronic inflammation signaling contributes to the pathogenesis of these prostate diseases are poorly understood. Previous efforts to therapeutically target the upstream (e.g., TLRs and IL1-Rs) and downstream (e.g., NF-κB subunits and cytokines) inflammatory signaling molecules in people with these conditions have been clinically ambiguous and unsatisfactory, hence fostering the recent paradigm shift towards unraveling and understanding the functional roles and clinical significance of the novel and relatively underexplored inflammatory molecules and pathways that could become potential therapeutic targets in managing prostatic diseases. In this review article, we exclusively discuss the causal and molecular drivers of prostatitis, BPH, and prostate tumorigenesis, as well as the potential impacts of microbiome dysbiosis and chronic inflammation in promoting prostate pathologies. We specifically focus on the importance of some of the underexplored druggable inflammatory molecules, by discussing how their aberrant signaling could promote prostate cancer (PCa) stemness, neuroendocrine differentiation, castration resistance, metabolic reprogramming, and immunosuppression. The potential contribution of the IL1R-TLR-IRAK-NF-κBs signaling molecules and NLR/inflammasomes in prostate pathologies, as well as the prospective benefits of selectively targeting the midstream molecules in the various inflammatory cascades, are also discussed. Though this review concentrates more on PCa, we envision that the information could be applied to other prostate diseases. In conclusion, we have underlined the molecular mechanisms and signaling pathways that may need to be targeted and/or further investigated to better understand the association between chronic inflammation and prostate diseases.

Abstract 1753: Deregulation and therapeutic potential of targeting IRAK3 as chronic inflammation suppressor in prostate cancer

Chronic inflammation is emerging as a targetable driver of tumorigenesis. During chronic inflammation, several inflammatory molecules are either activated or suppressed for a prolonged time. The oncogenic role of many of these inflammatory genes in prostate cancer (PCa) remains unexplored despite the increasing association of chronic inflammation with PCa initiation, progression, and therapy resistance in the scientific literature. The overarching goal of this study was to identify deregulated inflammatory suppressor genes, including interleukin-1 receptor-associated kinases 3 (IRAK3) as biomarkers for inflammation-driven PCa aggressiveness or progression. To achieve this, we utilize cutting-edge integrative (epi)genomic and transcriptomic techniques to investigate the role of IRAK3 in PCa progression, as well as the therapeutic potential of targeting IRAK3 in PCa. An array of computational tools was deployed to analyze Illumina HumanMethylation450K and whole exome RNAseq clinical datasets acquired from TCGA and cBioportal databases to identify differentially methylated and altered or expressed inflammatory suppressor genes in PCa patients/samples. We identified six inflammatory suppressor genes (IRAK3, TOLLIP, SOCS1, RNF216, IL1RL1, and TNFAIP3) to be significantly deregulated in indolent (n=493), metastatic (n=212), and lethal (n=50) PCa patients/samples. The expression patterns of these genes were correlated with clinical traits, such as age, progression-free status, overall survival status, biochemical recurrence, pathology as well as metastatic status using weighted gene co-expression network analysis, which identified IRAK3 as one of the top genes to explore. MutSigCV and GISTIC tools were used to identify somatic mutations and copy-number alterations. IRAK3 was found to be downregulated in most indolent, metastatic and lethal PCa samples. Its low expression correlated significantly with the progression, metastatic and recurrence statuses of the PCa. The genome-wide DNA methylation analysis of the 16 CpG probes identified in IRAK3 reveals hypermethylation (b-value or m-value < 0.01) at the promoter regions, which may be responsible for the observed transcriptional repression of IRAK3. Further analysis shows that DNA methylation is higher in PCa samples with mutated IRAK3 compared to those without the mutation. Mechanistic studies using genome-wide CRISPR-Cas9 gene-editing techniques were performed to create IRAK3+/+ or IRAK3-/- PCa clones. Using a series of bioassays, IRAK3 reactivation was found to inhibit PCa cell proliferation, migration, colony formation, and chemoresistance as well as induce apoptotic cell death. IRAK3+/+ PCa cells responded well to Taxane analogs compared to IRAK3-/- PCa cells. In conclusion, we have been able to demonstrate the tumor suppressor potential of IRAK3 in prostate cancer cells.

Citation Format: Saheed Oluwasina Oseni, Corey Naar, Magdalah Philemy, Genesis Acosta Laguer, Faika Ambrin, Sharlanda Metayer, Ariana Perez, Javoncia Betty, Preethika Praveen, James Hartmann, Mirjana Pavlovic, James Kumi-Diaka. Deregulation and therapeutic potential of targeting IRAK3 as chronic inflammation suppressor in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1753.

Abstract 995: Integrative genomic characterization and CRISPR-mediated gene editing studies identify IRAKs as novel therapeutic targets for inflammation-driven prostate tumorigenesis

A major drawback to accurate diagnosis and treatment of inflammation-driven prostate cancer (PCa) progression is our limited understanding of the molecular mechanisms underlying aberrant inflammation signaling in PCa patients. Since asymptomatic chronic inflammation is hard to diagnose, we do not have adequate knowledge of how specific genes within the inflammatory cascade drive PCa aggressiveness. Hence, an integrative genomic approach may provide us with effective prognostic and diagnostic tools to manage inflammation-driven PCa progression. The aim of this study was to characterize inflammation-associated hub genes as predictors of PCa progression and investigate the effect of aberrant signaling of interleukin-1 receptor-associated kinases (IRAKs) on prostate tumorigenesis. WES and RNA-seq datasets from a total of 726 PCa patients, stratified into subtypes: primary PCa (PPC; n=493), metastatic PCa (MPC; n=150) and the castration-resistant PCa (CRPC; n=52) and neuroendocrine PCa (NEPC; n=30) from 3 cohort studies were acquired from cBioPortal. A bioinformatics pipeline was designed to analyze the datasets. Weighted gene co-expression network analysis (WGCNA) was used to construct gene co-expression networks and identify inflammation hub genes associated with PCa progression. The top inflammation hub genes, such as ILR1, TLRs, IRAK1-4, and NF-kB were validated. IRAK1-4 hub genes were found to be differentially expressed and genetically altered in NEPC and CRPC (>40%) compared to PPC and MPC (<20%) patients. GISTIC and MutSigCV were used to identify somatic mutations and copy-number alterations (CNAs). IRAK1 was found to have the highest CNA in CRPC and NEPC compared to MPC and PPC patients. Interestingly, no mutation was identified in CRPC and NEPC patients. The co-occurrence of IRAK1/4 CNVs and mRNA with AR, PI3K and AURKA signaling pathways suggest a role in PCa progression. To mechanistically investigate the role of IRAK1/4 signaling on PCa progression, CRISPR-mediated knockdown of IRAK1/4 was performed in PCa cell lines (LNCaP, PC3, and NCI-H660). mRNA and protein expression analyses were performed to determine changes in the levels of AR, PI3K/AKT, and AURKA between IRAK1/4-/- and IRAK1/4+/+ cell lines. Inhibition of IRAK1/4 significantly altered AR, PI3K, and AURKA signaling, leading to a reduction in PCa viability and metastatic potential. To investigate the effect of aberrant IRAK1/4 signaling on chemoresistance induction, IRAK+/+ PCa cells were treated with either TLR agonists or IRAK1/4 inhibitors and then treated with different anticancer drugs, such as Enzalutamide, Docetaxel, and Alisertib (AURKA inhibitor) dose-dependently. IRAK1/4-/- cells were more susceptible to anticancer drug treatment compared to IRAK1+/+ cells. The combination treatments were shown to be synergistic, thereby suppressing inflammation-induced chemoresistance. In conclusion, we have identified IRAK1/4 as a potential target for treating inflammation-driven prostate cancer progression.

Citation Format: Saheed Oluwasina Oseni, Mirjana Pavlovic, James Hartmann, James Kumi-Diaka. Integrative genomic characterization and CRISPR-mediated gene editing studies identify IRAKs as novel therapeutic targets for inflammation-driven prostate tumorigenesis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 995.

Abstract 1487: Dysregulation of Interleukin-1 receptor-associated kinase 1 promotes prostate cancer-associated chronic inflammation and aggressiveness

For decades, chronic inflammation has been linked with cancer development. However, the molecular mechanisms of this association with respect to prostate cancer (PCa) aggressiveness are poorly understood. While previous studies exploiting the contributions of upstream and downstream inflammation signaling proteins to this oncogenic alliance have been clinically unsuccessful, the goal of our study is to elucidate the role of the often-neglected midstream inflammation regulatory proteins, such as the Interleukin-1 receptor-associated kinase 1 (IRAK1). We propose that the dysregulation of IRAK1 protein will promote PCa-associated chronic inflammation and aggressiveness. To explore the importance of IRAK1 in PCa-associated chronic inflammation and aggressiveness, both bioinformatics and experimental approaches were employed. Cutting-edge computational meta-analysis was used to characterize and assess the molecular patterns of gene expression and alteration of IRAK1 in clinical datasets of PCa patients acquired from open resource databases. Inflammation-associated PCa models were established by pre-exposure of aggressive PC3-CRPC cells to low doses (10ng-10µg/ml) of TLR-2, -3, -4 and -7/8 agonists, such as zymosan, poly (I:C), LPS, and resiquimod, respectively, which led to the upregulation of IRAK1 prior to mechanistic studies. Chronic inflammation was confirmed by measuring changes in the levels of IL-6/IL-12 via ELISA. IRAK1 mRNA and protein upregulation were analyzed by RT-PCR and western blot or immunofluorescent staining. Next, we investigated the effects of IRAK1 dysregulation on the aggressiveness of PCa cells by downregulating IRAK1 expression in PC3 cells by either pharmacologic inhibition with thymoquinone (an IRAK1 inhibitor) or via RNAi. MTT and colony forming assays were performed to assess the effects on cell viability and survival. IRAK1 mRNA and protein levels in PC3 cells following treatment with thymoquinone or IRAK1 inhibitor were measured using RT-PCR, western blot or immunocytochemistry. Cell migration was assessed by wound healing assay. Acridine orange/propidium iodide fluorescent staining and flow cytometry were used to analyze the effect on cell cycle and apoptosis. Our computational analysis shows that IRAK1 is commonly upregulated at the mRNA and protein levels and genetically altered/mutated in clinical PCa samples. Downregulation of IRAK1 by thymoquinone or RNAi in PC3 cells result in a decrease in cell viability, cell migration, and proinflammatory cytokines as well as an increase in apoptotic cell death in a dose and time-dependent manner. Upregulation of IRAK1 prior to treatment with PI3K/AKT/mTOR pathway inhibitors abrogates the anticancer effects of these drugs. Our study establishes IRAK1 as a promising therapeutic target to treat PCa-associated chronic inflammation and aggressiveness.

Citation Format: Saheed Oluwasina Oseni, Cynthia Nguyen, Mirjana Pavlovic, James Kumi-Diaka. Dysregulation of Interleukin-1 receptor-associated kinase 1 promotes prostate cancer-associated chronic inflammation and aggressiveness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1487.

Principal Component Analysis of Morphometric Traits of West African Dwarf Goats

The study was conducted to evaluate the principal component analysis of phenotypic attributes of West African Dwarf (WAD) goat. Data collected on the live body weight and twelve morphometric traits of the goats which were categorised into four age groups based on their dentition. The age groups were: less than 2years old, 2- 3years old, 3-4 years old and 4 years old. The data were subjected to a PCA and Cluster analyses using the multivariate procedure components of SAS (2003). Result revealed that highest values of morphometric traits were obtained in goats that of 4 years old. The rate of increase in body weight and other morphometric traits was high in age group of ˂2 years to age 2-3years compared to differences observed in others across the age group. Heart Girth had the highest correlation with body weight. Foreleg, neck, ear and hind leg lengths; wither height and rump height were weakly correlated with the body weight of the goats. Result revealed that two Principal components were retained in the first age group (age group˂2years) which accounted for 72.99% of the total variation. The first PC alone accounted for 63.13% of the total variation while PC2 accounted for the remaining 9.86%. From this study, it was concluded that there is interdependence among body weight and morphometric traits and that morphometric traits can be used in predicting live weight of WAD goats; PCA and Cluster could be exploited in breeding and selection programmes to acquire highly coordinated animal bodies using fewer measurements.

Abstract 5730: Co-targeting toll-like receptor and PI3K survival signaling pathways in stem-like castration resistant prostate cancer cells

The development of castration-resistant prostate cancer (CRPCs) has been linked to the ability of prostate cancer stem cells (PCSCs) to either resist or survive the inhibitory effect of androgen deprivation and radiation therapies. Dysregulation of the PI3K/Akt/mTOR pathway is a common phenomenon in CRPCs, resulting in survival, growth enhancement, resistance to apoptosis and altered metabolism. Toll-like receptors (TLRs) have been shown to be surprisingly expressed in prostate cancer cells, which when activated could lead to activation of innate immune response and activation of other cell signaling pathways. Since, recent studies have identified links between TLR signaling and prostate cancer, TLR polymorphisms and prostate cancer risk, as well as possible cross-talks between TLR signaling and the PI3K pathway in immune cells, we hypothesized that there is a link between PI3K signaling pathway and TLR signaling in CRPCs. Our aim is to determine the synergism between targeting PI3K and TLR signaling in a combination regimen. Methods: PTEN-/- (PC3) and PTEN-/+ (DU145) castration-resistant prostate cancer cell lines (CRPCs) were used for this experiment. CRPCs cells were cultured and enriched for CD44+ spheroid cells either by low dose radiation or in serum-free media. CRPCs and stem-like spheroid cells were then treated with different concentration of PI3K, AKT, and mTOR inhibitors, as well as TLR agonists /antagonists as monotherapy. Combination regimens were also done as assess the synergistic effects of PI3K/AKT/mTOR inhibitors and/or TLR ligands (agonists)/antagonists in CRPCs and/or spheroid cells. CRPCs or spheroid cells were assessed for treatment-induced effects such as cell viability (MTT assay), cell cytotoxicity (LDH), mode of cell death (fluorescent staining), protein expression profile (Western blot analysis), and redox activity (NBT assay). We also tested to assess treatment-induced inflammatory response via ELISA assay. Results: Our result shows that TLR 3, 4 and 9, were significantly differentially overexpressed in PTEN-/- CRPCs compared to PTEN-/+ CRPCs. The activation of these pathway results in PI3K signaling downstream. The co-targeting of PI3K signaling pathway with both PI3K inhibitors and TLR signaling modulators appears to be beneficial in preventing proliferation and stemness in PTEN-/- CRPCs compared to PTEN-/+ CRPCs. Co-administration of PI3K and TLR 4/9 agonist appears to be antagonistic but become synergistic when TLRs 4 and 9 signaling were inhibited using siRNAs. Conclusion: One of the advantages of this combination treatment method is that it proffers a solution to the often-encountered feedback loop observed when PI3K signaling inhibitors are used as monotherapy. This study has provided more insights on how targeting can be beneficial in the eradication of CRPCs when used along with PI3K signaling inhibitors.

Citation Format: Saheed Oluwasina Oseni, Rolando Branly, Mirjana Pavlovic, James Kumi-Diaka. Co-targeting toll-like receptor and PI3K survival signaling pathways in stem-like castration resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5730.

Chemopreventive Effects of Magnesium Chloride Supplementation on Hormone Independent Prostate Cancer Cells

Background: Lifestyle significantly impacts the risk factors associated with prostate cancer, out of which diet appears to be the most influential. An emerging chemopreventive approach, which involves the adequate intake of dietary constituents, has shown great potential in preventing the occurrence or progression of cancer. Magnesium is known to be an essential cofactor for more than 300 enzymatic processes, and is responsible for the regulation of various cellular reactions in the body. A plethora of studies have shown evidence that changes in the intracellular levels of magnesium could contribute to cell proliferation and apoptosis in some normal and malignant cells. The aim of the study was to investigate the effects of magnesium chloride (MgCl2) in DU-145 prostate cancer cells. Methodology: Cultured DU-145 cells were subjected to graded concentrations or doses (50-500 µM) of MgCl2 for 48 hours. The cell viability was assessed using MTT and Resazurin reduction assays. NBT assay was also used to assess the treatment-induced intracellular ROS levels. Acridine Orange/Ethidium Bromide (AcrO/EtBr) and Rh123/EtBr fluorescent stains were used to assess the cell death type and mitochondrial membrane potential (Δψm) respectively. Results: The results revealed a dose-dependent decrease (P < 0.05) in cell viability in treated DU-145 cells after 48 hours. The NBT assay also revealed a dose dependent biphasic response (P < 0.05) in intracellular levels of ROS. There was a drop (P < 0.05) in ROS levels in all groups except at 100 µM, where ROS level was higher than the control. Apoptosis was the primary mode of cell death as observed in the fluorescence analysis. Conclusion: Our finding suggests that MgCl2 may be potentially chemopreventive for prostate cancer. This justifies further studies into its mechanism of action in DU-145 and other prostate cancer cell types. Keywords: Prostate cancer, Magnesium chloride, Chemoprevention, Apoptosis, Reactive Oxygen Species.