A Paracrine Role for IL6 in Prostate Cancer Patients: Lack of Production by Primary or Metastatic Tumor Cells

IL-6 evoked biochemical changes in prostate cancer cells

The pro-inflammatory cytokine IL-6 has been associated with the progression of PCa to a castration-resistant phenotype. In this work, we characterized the biochemical changes evoked by IL-6 in three different models of PCa cells, including LNCaP, C4-2, and PC3. The effect of IL-6 on PCa cells was compared with the effect obtained by co-stimulation with the cAMP-inducing agent forskolin (FSK). Stimulation of LNCaP cells with IL-6 or IL-6 + FSK evoked increased expression of the neuroendocrine marker tubulin IIIβ and Cav3.2 T-type Ca²⁺ channel subunit. PC3 cells, representing a more advanced state of PCa, had high levels of tubulin IIIβ expression without any further changes observed by treatment with IL-6 or IL-6 + FSK. Elevated expression of the glucocorticoid receptor was observed in PC3, but not in LNCaP or C4-2 cells. Glucocorticoid receptor expression was not regulated by IL-6 stimulation of LNCaP or C4-2 cells. IL-6 acting alone or together with FSK evoked a significant reduction in the expression of the transcription factor REST and retinoblastoma tumor suppressor protein Rb1. In LNCaP cells, IL-6 acting alone or together with FSK had no effect on the expression of several biological markers of advanced PCa, including Aurora kinase A, valosin-containing protein, calcium-sensing receptor, calreticulin, S100A protein, and Protein S. In PC3 cells, co-treatment with IL-6 + FSK evoked increased expression of REST and S100A proteins, as well as a reduction in Protein S levels. These findings reveal a complex pattern of biochemical changes in PCa cells under the influence of IL-6.

Differential regulation of TNFα and IL-6 expression contributes to immune evasion in prostate cancer

BACKGROUND

The role of the inflammatory milieu in prostate cancer progression is not well understood. Differences in inflammatory signaling between localized and metastatic disease may point to opportunities for early intervention.

METHODS

We modeled PCa disease progression by analyzing RNA-seq of localized vs. metastatic patient samples, followed by CIBERSORTx to assess their immune cell populations. The VHA CDW registry of PCa patients was analyzed for anti-TNF clinical outcomes.

RESULTS

We observed statistically significant opposing patterns of IL-6 and TNFα expression between localized and metastatic disease. IL-6 was robustly expressed in localized disease and downregulated in metastatic disease. The reverse was observed with TNFα expression. Metastatic disease was also characterized by downregulation of adhesion molecule E-selectin, matrix metalloproteinase ADAMTS-4 and a shift to M2 macrophages whereas localized disease demonstrated a preponderance of M1 macrophages. Treatment with anti-TNF agents was associated with earlier stage disease at diagnosis.

CONCLUSIONS

Our data points to clearly different inflammatory contexts between localized and metastatic prostate cancer. Primary localized disease demonstrates local inflammation and adaptive immunity, whereas metastases are characterized by immune cold microenvironments and a shift towards resolution of inflammation and tissue repair. Therapies that interfere with these inflammatory networks may offer opportunities for early intervention in monotherapy or in combination with immunotherapies and anti-angiogenic approaches.

Health inequity drives disease biology to create disparities in prostate cancer outcomes

Prostate cancer exerts a greater toll on African American men than on White men of European descent (hereafter referred to as European American men): the disparity in incidence and mortality is greater than that of any other common cancer. The disproportionate impact of prostate cancer on Black men has been attributed to the genetics of African ancestry, to diet and lifestyle risk factors, and to unequal access to quality health care. In this Review, all of these influences are considered in the context of the evolving understanding that chronic or recurrent inflammatory processes drive prostatic carcinogenesis. Studies of inherited susceptibility highlight the contributions of genes involved in prostate cell and tissue repair (BRCA1/2, ATM) and regeneration (HOXB13 and MYC). Social determinants of health appear to accentuate these genetic influences by fueling prostate inflammation and associated cell and genome damage. Molecular characterization of the prostate cancers that arise in Black versus White men further implicates this inflammatory microenvironment in disease behavior. Yet, when Black and White men with similar grade and stage of prostate cancer are treated equally, they exhibit equivalent outcomes. The central role of prostate inflammation in prostate cancer development and progression augments the impact of the social determinants of health on disease pathogenesis. And, when coupled with poorer access to high-quality treatment, these inequities result in a disparate burden of prostate cancer on African American men.

Association of Genetic Polymorphisms and Serum Levels of IL-6 and IL-8 with the Prognosis in Children with Neuroblastoma

Simple Summary

Neuroblastoma (NB) presents diverse biological and clinical characteristics, from spontaneous regression to highly malignant and aggressive unfavorable tumors that condition the therapeutic failure of conventional treatments. The tumorigenesis of NB can be the result of different genetic variants, which can influence the clinical outcome, and the survival of patients who have metastatic tumors is low. The role of cytokines such as interleukin (IL)-6 has been described in the NB microenvironment promoting tumor progression and metastasis. Single nucleotide polymorphism (SNP)-174 G > C in IL-6 and -251 T > A and +781 C > T in IL-8 regulate the expression of these cytokines, and could be associated with the clinical outcome in patients with NB. Our objective was to evaluate the association of the genetic polymorphisms of IL-6 and IL-8, as well as the serum levels of these cytokines in patients with NB, as this will allow the genetic bases of NB to be characterized and understood, in order to predict the outcome of the disease and develop new therapeutic strategies.

Abstract

There is evidence that high circulating levels of IL-6 and IL-8 are markers of a poor prognosis in various types of cancer, including NB. The participation of these cytokines in the tumor microenvironment has been described to promote progression and metastasis. Our objective was to evaluate the prognostic role of genetic polymorphisms and serum levels of IL-6 and IL-8 in a cohort of Mexican pediatric patients with NB. The detection of the SNPs rs1800795 IL-6 and rs4073 and rs2227306 IL-8 was carried out by PCR-RFLP and the levels of cytokines were determined by the ELISA method. We found elevated circulating levels of IL-8 and IL-6 in NB patients compared to the control group. The genotype frequencies of the rs1800795 IL-6 and rs4073 IL-8 variants were different between the patients with NB and the control group. Likewise, the survival analysis showed that the GG genotypes of rs1800795 IL-6 (p = 0.014) and AA genotypes of rs4073 IL-8 (p = 0.002), as well as high levels of IL-6 (p = 0.009) and IL-8 (p = 0.046), were associated with lower overall survival. We confirmed the impact on an adverse prognosis in a multivariate model. This study suggests that the SNPs rs1800795 IL-6 and rs4073 IL-8 and their serum levels could be promising biomarkers of a poor prognosis, associated with overall survival, metastasis, and a high risk in Mexican children with NB.

Interleukin-6 Function and Targeting in Prostate Cancer

Interleukin-6 (IL-6) is a proinflammatory cytokine, which is involved in pathogenesis of several cancers. Its expression and function in prostate cancer have been extensively studied in cellular models and clinical specimens. High levels of IL-6 were detected in conditioned media from cells which do not respond to androgens. Increased phosphorylation of signal transducer and activator of transcription (STAT)3 factor which is induced in response to IL-6 is one of the typical features of prostate cancer. However, reports in the literature show regulation of neuroendocrine phenotype by IL-6. Effects of IL-6 on stimulation of proliferation, migration, and invasion lead to the establishment of experimental and clinical approaches to target IL-6. In prostate cancer, anti-IL-6 antibodies were demonstrated to inhibit growth in vitro and in vivo. Clinically, application of anti-IL-6 therapies did not improve survival of patients with metastatic prostate cancer. However, clinical trial design in the future may include different treatment schedule and combinations with experimental and clinical therapies. Endogenous inhibitors of IL-6 such as suppressors of cytokine signaling and protein inhibitors of activated STAT have variable effects on prostate cells, depending on presence or absence of the androgen receptor.

The STAT3-miR-223-TGFBR3/HMGCS1 axis modulates the progression of cervical carcinoma

Cervical cancer is induced by persistent infections with high-risk human papillomaviruses (HPVs), which produce the early protein 6 of HPVs (E6)/E7 protein that is involved in cell transformation by interacting with several oncoproteins or tumor suppressors. However, the role of noncoding RNA in mediating the pathogenesis of cervical cancer remains unclear. Here, we report that the novel signal transducer and activator of transcription 3 (STAT3)-microRNA-223-3p (miR-223)-TGFBR3/HMGCS1 axis regulated by the E6 protein controls cervical carcinogenesis. miR-223 was highly expressed in cervical tumor tissues, whereas TGFBR3 or HMGCS1 was significantly downregulated. miR-223 targeted the 3'-UTRs of TGFBR3 and HMGCS1 and suppressed their expression, leading to increased anchorage-independent growth and cervical squamous cell carcinoma (CSCC) tumor growth in vitro and in vivo. The increased expression of miR-223 was mediated by the transcription factor STAT3, whose activity was enhanced by E6 in the context of interleukin (IL)-6 stimulation. In addition, exosomal miR-223 derived from CSCC cells induced IL-6 secretion by monocyte/macrophage in a coculture system in vitro, and IL-6 secretion, in turn, led to enhanced STAT3 activity in CSSC cells, forming a positive feedback loop. Furthermore, modified miR-223 inhibitor effectively suppressed tumor growth in cell line-derived xenograft model, suggesting that miR-223 is a potential promising therapeutic target in CSCC. In conclusion, our results demonstrate that the STAT3-miR-223-HMGCS1/TGFBR3 axis functions as a key signaling pathway in cervical cancer progression and provides a new therapeutic target.

Role of miRNAs in prostate cancer: Do we really know everything?

Many different genetic alterations, as well as complex epigenetic interactions, are the basis of the genesis and progression of prostate cancer (CaP). This is the reason why until now the molecular pathways related to development of this cancer were only partly known, and even less those that determine aggressive or indolent tumour behaviour. MicroRNAs (miRNAs) represent a class of about 22 nucleotides long, small non-coding RNAs, which are involved in gene expression regulation at the post-transcriptional level. MiRNAs play a crucial role in regulating several biological functions and preserving homeostasis, as they carry out a wide modulatory activity on various molecular signalling pathways. MiRNA genes are placed in cancer-related genomic regions or in fragile sites, and they have been proven to be involved in the main steps of carcinogenesis as oncogenes or oncosuppressors in many types of cancer, including CaP. We performed a narrative review to describe the relationship between miRNAs and the crucial steps of development and progression of CaP. The aims of this study were to improve the knowledge regarding the mechanisms underlying miRNA expression and their target genes, and to contribute to understanding the relationship between miRNA expression profiles and CaP.

Association between immunosuppressive cytokines and PSA progression in biochemically recurrent prostate cancer treated with intermittent hormonal therapy

BACKGROUND

Immunosuppressive cytokines have the potential to promote prostate cancer progression. Assessing their longitudinal changes may implicate mechanisms of progression, treatment resistance, and suggest new therapeutic targets.

METHODS

Thirty-seven men with biochemically recurrent (BCR) prostate cancer who received 6 months of androgen deprivation therapy (ADT) and were monitored until the time to prostate-specific antigen progression (TTPP) were identified from a completed phase III trial (NCT00020085). Serum samples were archived at baseline, 3 months after ADT, and at TTPP. Cytokine concentrations were quantified using a 36-parameter electrochemiluminescence assay. The Wilcoxon signed-rank sum test was used to compare observations between time points. Kaplan-Meier analysis was used to calculate TTPP dichotomized by cytokine values above or below the median. Pearson's rank correlation coefficient was used to compare continuous variables.

RESULTS

Median TTPP was 399 days (range, 114-1641). Median prostate-specific antigen (PSA) at baseline and progression were 8.5 and 5.3 ng/mL, respectively. Twenty-three patients (62%) achieved undetectable PSA with ADT. Castrate levels of testosterone (<50 ng/dL) after 3 months of ADT occurred in 35 patients (95%). TNF-α (P = .002), IL-23 (P = .002), and CXCL10 (P = .001) significantly increased from baseline to post ADT. Certain cytokines correlated longitudinally: TNF-α correlated with IL-23 (r = .72; P < .001) and IL-8 (r = .59; P < .001) from baseline to post ADT and to PSA progression. Neutrophil-to-lymphocyte ratio correlated with IL-27 (r = .57; P < .001) and MIP-3α (r = .56; P < .001). Patients with a detectable PSA after ADT had elevated levels of IL-6 (P = .049) and IL-8 (P = .013) at PSA progression as compared with those with an undetectable PSA. There was a trend toward shorter TTPP in patients with TNF-α levels above the median (P = .042).

CONCLUSIONS

Several innate cytokines were associated with biochemically recurrent prostate cancer.

Mass Cytometry Imaging for the Study of Human Diseases-Applications and Data Analysis Strategies

High parameter imaging is an important tool in the life sciences for both discovery and healthcare applications. Imaging Mass Cytometry (IMC) and Multiplexed Ion Beam Imaging (MIBI) are two relatively recent technologies which enable clinical samples to be simultaneously analyzed for up to 40 parameters at subcellular resolution. Importantly, these "Mass Cytometry Imaging" (MCI) modalities are being rapidly adopted for studies of the immune system in both health and disease. In this review we discuss, first, the various applications of MCI to date. Second, due to the inherent challenge of analyzing high parameter spatial data, we discuss the various approaches that have been employed for the processing and analysis of data from MCI experiments.

Consequences of interleukin 1β-triggered chronic inflammation in the mouse prostate gland: Altered architecture associated with prolonged CD4+ infiltration mimics human proliferative inflammatory atrophy

BACKGROUND

Elevated expression of the proinflammatory cytokine interleukin 1β (IL-1β) has been observed in expressed prostatic secretions of patients with chronic prostatitis/chronic pelvic pain syndrome, and genetic polymorphisms associated with the IL1B gene are linked to increased risk for aggressive prostate cancer.

METHODS

To study the role of IL-1β expression in prostate inflammation, we examined IL1B expression in human prostatic proliferative inflammatory atrophy (PIA) lesions and developed a tetracycline-regulated human IL1B transgene in the mouse prostate.

RESULTS

Here, we demonstrate that IL1B expression is a common finding in human PIA lesions, which harbored focal IL1B expression in epithelial and stromal compartments. Human IL1B expression in the mouse prostate elicited acute and chronic inflammation. Penetrance and expressivity were variable and tunable by altering transgene dosage and the presence of an exogenous inducible marker antigen (green fluorescent protein). Inflammation was characterized by infiltration of CD4+ T cells, demonstrating an adaptive immune response. Chronic inflammation persisted after doxycycline (Dox) withdrawal. Reactive epithelia increased expression of downstream cytokines, and altered glandular architecture was observed upon sustained induction of IL1B. Immunohistochemical analyses revealed a higher proliferative index and decreased Nkx3.1 expression in inflamed mouse prostates.

CONCLUSIONS

These data implicate IL-1β in human prostate pathology and this model provides a versatile platform to interrogate molecular mechanisms of inflammation-associated prostate pathologies associated with episodic or sustained IL-1β expression.

Reduced T-cell Numbers and Elevated Levels of Immunomodulatory Cytokines in Metastatic Prostate Cancer Patients De Novo Resistant to Abiraterone and/or Enzalutamide Therapy

Currently, there are two Food and Drug Administration (FDA)-approved drugs for androgen deprivation therapy (ADT) of metastatic castration-resistant prostate cancer (mCRPC) patients: abiraterone and enzalutamide. However, our understanding of the effect of these therapies on the immune system in mCRPC patients remains limited. Here, we examined how abiraterone and enzalutamide treatment affects levels of soluble immune mediators in plasma and in circulating immune cells of 44 mCRPC patients. We found that the baseline levels of cytokines fibroblast growth factor (FGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 10 (IL-10), and IL-6 were significantly lower in ADT-sensitive compared to de novo resistant patients. In addition, resistant patients showed significantly lower T cell frequencies. When comparing the levels of cytokines over the course of treatment, we observed that the levels of proinflammatory mediators, such as interferon-γ (IFN-γ), IL-5, macrophage inflammatory protein 1 alpha (MIP-1α), and tumor necrosis factor alpha (TNFα), were significantly increased in the ADT-sensitive patients. At the same time, the abiraterone/enzalutamide therapy did not reduce the percentage of tolerogenic myeloid cell populations, such as polymorphonuclear myeloid-derived suppressor cells, which retained unaltered expression of programmed death-ligand 1 (PD-L1) and B7-H3. Overall, our results suggest that certain immune markers, such as IL-6 and the frequency of effector T cells, could be predictive of therapeutic response to ADT therapies in mCRPC patients.

A role for paracrine interleukin-6 signaling in the tumor microenvironment in prostate tumor growth

BACKGROUND

Interleukin-6 (IL-6) is a mediator of inflammation that can facilitate prostate cancer progression. We previously demonstrated that IL-6 is present in the prostate tumor microenvironment and is restricted almost exclusively to the stromal compartment. The present study examined the influence of paracrine IL-6 signaling on prostate tumor growth using allograft models of mouse prostate cancer (TRAMP-C2), colon cancer (MC38), and melanoma (B16) cell lines in wildtype (WT) and IL-6 knockout (IL-6^-/- ) mice.

METHODS

Cells were implanted into WT or IL-6^-/- mice and tumor sizes were measured at a 3 to 4 day interval. Serum, tumors, and other organs were collected for IL-6 analysis by ELISA and RNA in situ hybridization (RISH).

RESULTS

There was a significant reduction in TRAMP-C2 and B16 tumor size grown in IL-6^-/- mice versus WT mice (P = 0.0006 and P = 0.02, respectively). This trend was not observed for the MC38 cell line. RISH analysis of TRAMP-C2 tumors grown in WT mice showed that cells present in the tumor microenvironment were the primary source of IL-6 mRNA, not the TRAMP-C2 cells. Serum IL-6 ELISA analyses showed an increase in the circulating levels of IL-6 in WT mice bearing TRAMP-C2 tumors. Similar phospho-STAT3 expression and tumor vascularization were observed in TRAMP-C2 tumors grown in WT and IL-6^-/- mice.

CONCLUSIONS

Our results are consistent with previous studies in prostate cancer patients demonstrating that paracrine IL-6 production in the tumor microenvironment may influence tumor growth. Additionally, these data provide evidence that elevated systemic IL-6 levels may be involved in tumor growth regulation in prostate cancer, and are not simply caused by or indicative of tumor burden.

If this is true, what does it imply? How end-user antibody validation facilitates insights into biology and disease

Antibodies are employed ubiquitously in biomedical sciences, including for diagnostics and therapeutics. One of the most important uses is for immunohistochemical (IHC) staining, a process that has been improving and evolving over decades. IHC is useful when properly employed, yet misuse of the method is widespread and contributes to the "reproducibility crisis" in science. We report some of the common problems encountered with IHC assays, and direct readers to a wealth of literature documenting and providing some solutions to this problem. We also describe a series of vignettes that include our approach to analytical validation of antibodies and IHC assays that have facilitated a number of biological insights into prostate cancer and the refutation of a controversial association of a viral etiology in gliomas. We postulate that a great deal of the problem with lack of accuracy in IHC assays stems from the lack of awareness by researchers for the critical necessity for end-users to validate IHC antibodies and assays in their laboratories, regardless of manufacturer claims or past publications. We suggest that one reason for the pervasive lack of end-user validation for research antibodies is that researchers fail to realize that there are two general classes of antibodies employed in IHC. First, there are antibodies that are "clinical grade" reagents used by pathologists to help render diagnoses that influence patient treatment. Such diagnostic antibodies, which tend to be highly validated prior to clinical implementation, are in the vast minority (e.g. < 500). The other main class of antibodies are "research grade" antibodies (now numbering >3 800 000), which are often not extensively validated prior to commercialization. Given increased awareness of the problem, both the United States, National Institutes of Health and some journals are requiring investigators to provide evidence of specificity of their antibody-based assays.

The STAT3 Inhibitor Galiellalactone Reduces IL6-Mediated AR Activity in Benign and Malignant Prostate Models

IL6/STAT3 signaling is associated with endocrine therapy resistance in prostate cancer, but therapies targeting this pathway in prostate cancer were unsuccessful in clinical trials so far. The mechanistic explanation for this phenomenon is currently unclear; however, IL6 has pleiotropic effects on a number of signaling pathways, including the androgen receptor (AR). Therefore, we investigated IL6-mediated AR activation in prostate cancer cell lines and ex vivo primary prostate tissue cultures in order to gain a better understanding on how to inhibit this process for future clinical trials. IL6 significantly increased androgen-dependent AR activity in LNCaP cells but importantly did not influence AR activity at castrate androgen levels. To identify the underlying mechanism, we investigated several signaling pathways but only found IL6-dependent changes in STAT3 signaling. Biochemical inhibition of STAT3 with the small-molecule inhibitor galiellalactone significantly reduced AR activity in several prostate and breast cancer cell lines. We confirmed the efficacy of galiellalactone in primary tissue slice cultures from radical prostatectomy samples. Galiellalactone significantly reduced the expression of the AR target genes PSA (P < 0.001), TMPRSS2 (P < 0.001), and FKBP5 (P = 0.003) in benign tissue cultures (n = 24). However, a high heterogeneity in the response of the malignant samples was discovered, and only a subset of tissue samples (4 out of 10) had decreased PSA expression upon galiellalactone treatment. Taken together, this finding demonstrates that targeting the IL6/STAT3 pathway with galiellalactone is a viable option to decrease AR activity in prostate tissue that may be applied in a personalized medicine approach.

Serum IL-6 and IL-8 Correlate with Prognostic Factors in Ovarian Cancer

The aim of the study was to correlate serum levels of IL-2, IL-5, IL-6, IL-8, IL-10, and TNF-α with clinical, laboratory, and pathological prognostic factors in patients with primary ovarian malignancy. Patients treated at the Pelvic Mass Ambulatory of the Discipline of Gynecology and Obstetrics/Oncology Research Institute (IPON) of the UFTM with confirmed diagnosis of malignant ovarian neoplasia (n = 26) were evaluated. Serum collection was performed preoperatively for the determination of tumor markers. The cytokines IL-2, IL-5, IL-6, IL-8, IL-10, and TNF-α were assayed by enzyme-linked immunosorbent assay (ELISA). The prognostic factors were compared using the Mann-Whitney test, with significance level lower than 0.05. When evaluating IL6, it was observed that higher serum levels were associated with overall survival less than 60 months (p = 0.0382). In the evaluation of IL8, higher serum levels were associated with neutrophil-to-lymphocyte ratio (NLR) ≥ 4 and platelet-to-lymphocyte ratio (PLR) ≥ 200 (p = 0.0198 and p = 0.0072, respectively), altered values of serum CA125 (p = 0.0457), and stage IIIC (p = 0.0486). Therefore, increased levels of IL-6 and IL-8 are associated with factors of worse prognosis in ovarian cancer. Additional studies with a larger sample of patients are needed to confirm the role of cytokines as prognostic factors, in the definition of treatment, and in the development of future target therapies.

Exogenous IL-6 induces mRNA splice variant MBD2_v2 to promote stemness in TP53 wild-type, African American PCa cells

African American men (AAM) are at higher risk of being diagnosed with prostate cancer (PCa) and are at higher risk of dying from the disease compared to European American men (EAM). We sought to better understand PCa molecular diversity that may be underlying these disparities. We performed RNA‐sequencing analysis on high‐grade PCa to identify genes showing differential tumor versus noncancer adjacent tissue expression patterns unique to AAM or EAM. We observed that interleukin‐6 (IL‐6) was upregulated in the nonmalignant adjacent tissue in AAM, but in EAM IL‐6 expression was higher in PCa tissue. Enrichment analysis identified that genes linked to the function of TP53 were overrepresented and downregulated in PCa tissue from AAM. These RNA‐sequencing results informed our subsequent investigation of a diverse PCa cell line panel. We observed that PCa cell lines that are TP53 wild‐type, which includes cell lines derived from AAM (MDA‐PCa‐2b and RC77T), did not express detectable IL‐6 mRNA. IL‐6 treatment of these cells downregulated wild‐type TP53 protein and induced mRNA and protein expression of the epigenetic reader methyl CpG binding domain protein 2 (MBD2), specifically the alternative mRNA splicing variant MBD2_v2. Further investigation validated that upregulation of this short isoform promotes self‐renewal and expansion of PCa cancer stem‐like cells (CSCs). In conclusion, this report contributes to characterizing gene expression patterns in high‐grade PCa and adjacent noncancer tissues from EAM and AAM. The results we describe here advance what is known about the biology associated with PCa race disparities and the molecular signaling of CSCs.

High-Fat Diet-Induced Inflammation Accelerates Prostate Cancer Growth via IL6 Signaling

Purpose: High-fat diet (HFD) could induce prostate cancer progression. The aim of this study is to identify mechanisms of HFD-induced prostate cancer progression, focusing on inflammation.Experimental Design: We administered HFD and celecoxib to autochthonous immunocompetent Pb-Cre⁺;Pten(fl/fl) model mice for prostate cancer. Tumor growth was evaluated by tumor weight and Ki67 stain, and local immune cells were assessed by flow cytometry at 22 weeks of age. Cytokines which correlated with tumor growth were identified, and the changes of tumor growth and local immune cells after inhibition of the cytokine signals were evaluated in the mice. IHC analyses using prostatectomy specimens of obese patients were performed.Results: HFD accelerated tumor growth and increased the myeloid-derived suppressor cells (MDSCs) fraction and M2/M1 macrophage ratio in the model mice. Celecoxib-suppressed tumor growth, and decreased both local MDSCs and M2/M1 macrophage ratio in HFD-fed mice. HFD-induced tumor growth was associated with IL6 secreted by prostatic macrophages, as were phosphorylated STAT3 (pSTAT3)-positive tumor cells. Anti-IL6 receptor antibody administration suppressed tumor growth, and decreased local MDSCs and pSTAT3-positive cell fractions in HFD-fed mice. The tumor-infiltrating CD11b-positive cell count was significantly higher in prostatectomy specimens of obese than those of nonobese patients with prostate cancer.Conclusions: HFD increased MDSCs and accelerated prostate cancer tumor growth via IL6/pSTAT3 signaling in the mice. This mechanism could exist in obese patients with prostate cancer. IL6-mediated inflammation could be a therapeutic target for prostate cancer. Clin Cancer Res; 24(17); 4309-18. ©2018 AACR.

Lipid pathway deregulation in advanced prostate cancer

The link between prostate cancer (PC) development and lipid metabolism is well established, with AR intimately involved in a number of lipogenic processes involving SREBP1, PPARG, FASN, ACC, ACLY and SCD1. Recently, there is growing evidence implicating the role of obesity and peri-prostatic adipose tissue (PPAT) in PC aggressiveness and related mortality, suggesting the importance of lipid pathways in both localised and disseminated disease. A number of promising agents are in development to target the lipogenic axis in PC, and the likelihood is that these agents will form part of combination drug strategies, with targeting of multiple metabolic pathways (e.g. FASN and CPT1), or in combination with AR pathway inhibitors (SCD1 and AR).

Sprouty2 loss-induced IL6 drives castration-resistant prostate cancer through scavenger receptor B1

Metastatic castration-resistant prostate cancer (mCRPC) is a lethal form of treatment-resistant prostate cancer and poses significant therapeutic challenges. Deregulated receptor tyrosine kinase (RTK) signalling mediated by loss of tumour suppressor Sprouty2 (SPRY2) is associated with treatment resistance. Using pre-clinical human and murine mCRPC models, we show that SPRY2 deficiency leads to an androgen self-sufficient form of CRPC Mechanistically, HER2-IL6 signalling axis enhances the expression of androgen biosynthetic enzyme HSD3B1 and increases SRB1-mediated cholesterol uptake in SPRY2-deficient tumours. Systemically, IL6 elevated the levels of circulating cholesterol by inducing host adipose lipolysis and hepatic cholesterol biosynthesis. SPRY2-deficient CRPC is dependent on cholesterol bioavailability and SRB1-mediated tumoral cholesterol uptake for androgen biosynthesis. Importantly, treatment with ITX5061, a clinically safe SRB1 antagonist, decreased treatment resistance. Our results indicate that cholesterol transport blockade may be effective against SPRY2-deficient CRPC.

Obesity does not promote tumorigenesis of localized patient-derived prostate cancer xenografts

There are established epidemiological links between obesity and the severity of prostate cancer. We directly tested this relationship by assessing tumorigenicity of patient-derived xenografts (PDXs) of moderate-grade localized prostate cancer in lean and obese severe combined immunodeficiency (SCID) mice. Mice were rendered obese and insulin resistant by high-fat feeding for 6 weeks prior to transplantation, and PDXs were assessed 10 weeks thereafter. Histological analysis of PDX grafts showed no differences in tumor pathology, prostate-specific antigen, androgen receptor and homeobox protein Nkx-3.1 expression, or proliferation index in lean versus obese mice. Whilst systemic obesity per se did not promote prostate tumorigenicity, we next asked whether the peri-prostatic adipose tissue (PPAT), which covers the prostate anteriorly, plays a role in prostate tumorigenesis. In vitro studies in a cellularized co-culture model of stromal and epithelial cells demonstrated that factors secreted from human PPAT are pro-tumorigenic. Accordingly, we recapitulated the prostate-PPAT spatial relationship by co-grafting human PPAT with prostate cancer in PDX grafts. PDX tissues were harvested 10 weeks after grafting, and histological analysis revealed no evidence of enhanced tumorigenesis with PPAT compared to prostate cancer grafts alone. Altogether, these data demonstrate that prostate cancer tumorigenicity is not accelerated in the setting of diet-induced obesity or in the presence of human PPAT, prompting the need for further work to define the at-risk populations of obesity-driven tumorigenesis and the biological factors linking obesity, adipose tissue and prostate cancer pathogenesis.

Immune-suppressive effects of interleukin-6 on T-cell-mediated anti-tumor immunity

Accompanied by the growing clinical applications of immunotherapy in the treatment of cancer patients, development of novel therapeutic approaches to reverse the immune-suppressive environment in cancer patients is eagerly anticipated, because the success of cancer immunotherapy is currently limited by immune-suppressive effects in tumor-bearing hosts. Interleukin (IL)-6, a pleotropic proinflammatory cytokine, participates in tumor cell-autonomous processes that are required for their survival and growth, and is therefore known as a poor prognostic factor in cancer patients. In addition, an emerging role of IL-6 in modulating multiple functions of immune cells including T cells, dendritic cells, and macrophages is responsible for the dysfunction of innate and adaptive immunity against tumors. Therefore, the IL-6-targeting approach is of value as a promising strategy for desensitization and prevention of immune-suppressive effects, and should be an effective treatment when combined with current immunotherapies. The aim of the present review is to discuss the immune-suppressive aspects of IL-6, notably with modification of T-cell functions in cancer patients, and their relationship to anti-tumor immune responses and cancer immunotherapy.

Rapid Loss of RNA Detection by In Situ Hybridization in Stored Tissue Blocks and Preservation by Cold Storage of Unstained Slides

OBJECTIVES

Recent commercialization of methods for in situ hybridization using Z-pair probe/branched DNA amplification has led to increasing adoption of this technology for interrogating RNA expression in formalin-fixed, paraffin-embedded (FFPE) tissues. Current practice for FFPE block storage is to maintain them at room temperature, often for many years.

METHODS

To examine the effects of block storage time on FFPE tissues using a number of RNA in situ probes with the Advanced Cellular Diagnostic's RNAscope assay.

RESULTS

We report marked reductions in signals after 5 years and significant reductions often after 1 year. Furthermore, storing unstained slides cut from recent cases (<1 year old) at -20°C can preserve hybridization signals significantly better than storing the blocks at room temperature and cutting the slides fresh when needed.

CONCLUSIONS

We submit that the standard practice of storing FFPE tissue blocks at room temperature should be reevaluated to better preserve RNA for in situ hybridization.

Immune-suppressive effects of interleukin-6 on T-cell-mediated anti-tumor immunity

Accompanied by the growing clinical applications of immunotherapy in the treatment of cancer patients, development of novel therapeutic approaches to reverse the immune-suppressive environment in cancer patients is eagerly anticipated, because the success of cancer immunotherapy is currently limited by immune-suppressive effects in tumor-bearing hosts. Interleukin (IL)-6, a pleotropic proinflammatory cytokine, participates in tumor cell-autonomous processes that are required for their survival and growth, and is therefore known as a poor prognostic factor in cancer patients. In addition, an emerging role of IL-6 in modulating multiple functions of immune cells including T cells, dendritic cells, and macrophages is responsible for the dysfunction of innate and adaptive immunity against tumors. Therefore, the IL-6-targeting approach is of value as a promising strategy for desensitization and prevention of immune-suppressive effects, and should be an effective treatment when combined with current immunotherapies. The aim of the present review is to discuss the immune-suppressive aspects of IL-6, notably with modification of T-cell functions in cancer patients, and their relationship to anti-tumor immune responses and cancer immunotherapy.

The Role and Mechanism of Epithelial-to-Mesenchymal Transition in Prostate Cancer Progression

In prostate cancer (PCa), similar to many other cancers, distant organ metastasis symbolizes the beginning of the end disease, which eventually leads to cancer death. Many mechanisms have been identified in this process that can be rationalized into targeted therapy. Among them, epithelial-to-mesenchymal transition (EMT) is originally characterized as a critical step for cell trans-differentiation during embryo development and now recognized in promoting cancer cells invasiveness because of high mobility and migratory abilities of mesenchymal cells once converted from carcinoma cells. Nevertheless, the underlying pathways leading to EMT appear to be very diverse in different cancer types, which certainly represent a challenge for developing effective intervention. In this article, we have carefully reviewed the key factors involved in EMT of PCa with clinical correlation in hope to facilitate the development of new therapeutic strategy that is expected to reduce the disease mortality.

Myeloid-derived cells in prostate cancer progression: phenotype and prospective therapies

Prostate cancer is the second most common cause of cancer mortality in men in the United States. As is the case for other tumor types, accumulating evidence suggests an important role for myeloid-derived cells in the promotion and progression of prostate cancer. Here, we briefly describe myeloid-derived cells that interact with tumor cells and what is known about their immune suppressive function. We next discuss new evidence for tumor cell-mediated myeloid infiltration via the PI3K/PTEN/AKT signaling pathway and an alternative mechanism for immune evasion that may be regulated by an endoplasmic reticulum stress response. Finally, we discuss several interventions that target myeloid-derived cells to treat prostate cancer.

TLR9 expression and secretion of LIF by prostate cancer cells stimulates accumulation and activity of polymorphonuclear MDSCs

Proinflammatory signals promote prostate tumorigenesis and progression, but their origins and downstream effects remain unclear. We recently demonstrated that the expression of an innate immune receptor, TLR9, by prostate cancer cells is critical for their tumor-propagating potential. We investigated whether cancer cell-intrinsic TLR9 signaling alters composition of the prostate tumor microenvironment. We generated Ras/Myc (RM9) and Myc-driven (Myc-CaP) prostate cancer cells expressing the tetracycline-inducible gene Tlr9 (Tlr9^ON ) or the control LacZ (LacZ^ON ). When engrafted into mice and treated with tetracycline, Tlr9^ON , but not LacZ^ON , tumors showed accelerated growth kinetics compared with tumors in PBS-treated mice. Tlr9 upregulation in cancer cells triggered the selective accumulation of CD11b⁺Ly6G^HILy6C^LO myeloid cells, phenotypically similar to PMN-MDSCs. The PMN-MDSCs from tetracycline-treated RM9-Tlr9^ON tumors increased the immunosuppressive activity of the STAT3 transcription factor, thereby more potently inhibiting T cell proliferation. We identified LIF, an IL-6-type cytokine and STAT3 activator, as a potential mediator of crosstalk between TLR9-expressing prostate cancer cells and PMN-MDSCs. Antibody-mediated LIF neutralization reduced the percentage of tumor-infiltrating PMN-MDSCs and inhibited tumor growth in mice. The clinical relevance of LIF is confirmed by the correlation between TLR9 and LIF expression in prostate cancer specimens. Furthermore, blood samples from patients with prostate cancer showed elevated levels of LIF and high LIFR expression on circulating PMN-MDSCs. Our results suggest that TLR9⁺ prostate cancers promote immune evasion via LIF-mediated expansion and activation of PMN-MDSCs. Finally, targeting TLR9/LIF/STAT3 signaling using oligonucleotide-based inhibitors, such as CpG-STAT3dODN, can offer new opportunities for prostate cancer immunotherapy.

Prostate-specific IL-6 transgene autonomously induce prostate neoplasm through amplifying inflammation in the prostate and peri-prostatic adipose tissue

Background

The causative role of the pro-inflammatory cytokine IL-6 in prostate cancer progression has been well established at molecular level. However, whether and how IL-6 may play a role in prostate cancer risk and development is not well defined. One limitation factor to acquiring this knowledge is the lack of appropriate animal models.

Methods

We generated a novel line of prostate-specific IL-6 transgenic mouse model. We compared the prostate pathology, tumorigenic signaling components, and prostate tumor microenvironment of the IL-6 transgenic mice with wild type littermates.

Results

With this model, we demonstrate that IL-6 induces prostate neoplasm autonomously. We further demonstrate that transgenic expression of IL-6 in the prostate activates oncogenic pathways, induces autocrine IL-6 secretion and steadily-state of STAT3 activation in the prostate tissue, upregulates paracrine insulin-like growth factor (IGF) signaling axis, reprograms prostate oncogenic gene expression, and more intriguingly, amplifies inflammation in the prostate and peri-prostatic adipose tissue.

Conclusions

The pro-inflammatory IL-6 is autonomous oncogene for the prostate. IL-6 induces prostate oncogenesis through amplifying local inflammation. We also presented a valuable animal model to study inflammation and prostate cancer development.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0386-7) contains supplementary material, which is available to authorized users.

Expression of STAT3 in Prostate Cancer Metastases

STAT3 and its upstream activator IL6R have been implicated in the progression of prostate cancer and are possible future therapeutic targets. We analyzed 223 metastatic samples from rapid autopsies of 71 patients who had died of castration-resistant prostate cancer (CRPC) to study protein and gene expression of pSTAT3 and IL6R. Immunohistochemical analysis revealed that 95% of metastases were positive for pSTAT3 and IL6R, with varying expression levels. Bone metastases showed significantly higher expression of both pSTAT3 and IL6R in comparison to lymph node and visceral metastases. STAT3 mRNA levels were significantly higher in bone than in lymph node and visceral metastases, whereas no significant difference in IL6R mRNA expression was observed. Our study strongly supports the suggested view of targeting STAT3 as a therapeutic option in patients with metastatic CRPC.

PATIENT SUMMARY

We studied the levels of two proteins (pSTAT3 and IL6R) in metastases from patients who died from castration-resistant prostate cancer. We found high levels of pSTAT3and IL6R in bone metastases, suggesting that these proteins could be used as targets for new anticancer drugs.

Linking obesogenic dysregulation to prostate cancer progression

The global epidemic of obesity is closely linked to the development of serious co-morbidities, including many forms of cancer. Epidemiological evidence consistently shows that obesity is associated with a similar or mildly increased incidence of prostate cancer but, more prominently, an increased risk for aggressive prostate cancer and prostate cancer-specific mortality. Studies in mice demonstrate that obesity induced by high-fat feeding increases prostate cancer progression; however, the mechanisms underpinning this relationship remain incompletely understood. Adipose tissue expansion in obesity leads to local tissue dysfunction and is associated with low-grade inflammation, alterations in endocrine function and changes in lipolysis that result in increased delivery of fatty acids to tissues of the body. The human prostate gland is covered anteriorly by the prominent peri-prostatic adipose tissue and laterally by smaller adipose tissue depots that lie directly adjacent to the prostatic surface. We discuss how the close association between dysfunctional adipose tissue and prostate epithelial cells might result in bi-directional communication to cause increased prostate cancer aggressiveness and progression. However, the literature indicates that several 'mainstream' hypotheses regarding obesity-related drivers of prostate cancer progression are not yet supported by a solid evidence base and, in particular, are not supported by experiments using human tissue. Understanding the links between obesity and prostate cancer will have major implications for the health policy for men with prostate cancer and the development of new therapeutic or preventative strategies.

Bacterial Prostatitis Enhances 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]Pyridine (PhIP)-Induced Cancer at Multiple Sites

Dietary carcinogens, such as 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and chronic inflammation have each been implicated as etiologic agents in prostate cancer. We hypothesized that bacterial prostatitis would accelerate PhIP-induced preinvasive lesions in the rat prostate. Male Fischer 344 rats were assigned into 4 groups: Control (untreated), PhIP (200 ppm in the diet for 20 weeks), Escherichia coli (E. coli, prostatic inoculation in week 10), or PhIP + E. coli. Study animals were monitored for a total of 52 weeks and were euthanized as necessary based on strict criteria for health status and tumor burden. Animals treated with E. coli initially developed acute and chronic inflammation in all lobes of the prostate, whereas inflammation was observed predominantly in the ventral lobe at time of death. PhIP + E. coli-treated animals exhibited a marked decrease in survival compared with PhIP-alone-treated animals as a result of an increase in the number of invasive cancers that developed at multiple sites, including the skin, small intestine, and Zymbal's gland. Despite their earlier mortality, PhIP + E. coli-treated animals developed an increased average number of precancerous lesions within the prostate compared with PhIP-treated animals, with a significantly increased Ki-67 index. Multiplexed serum cytokine analysis indicated an increase in the level of circulating IL6 and IL12 in PhIP + E. coli-treated animals. Elevated serum IL6 levels correlated with the development of precancerous lesions within the prostate. These results suggest that bacterial infections and dietary carcinogens, two conceivably preventable cancer risk factors, may synergistically promote tumorigenesis.