Release of macrophage migration inhibitory factor by neuroendocrine-differentiated LNCaP cells sustains the proliferation and survival of prostate cancer cells

Macrophage dynamics in prostate cancer: Molecular to therapeutic insights

This review provides an in-depth examination of the role that tumor-associated macrophages (TAMs) play in the progression of prostate cancer (PCa), with a particular focus on the factors influencing the polarization of M1 and M2 macrophages and the implications of targeting these cells for cancer progression. The development and prognosis of PCa are significantly influenced by the behavior of macrophages within the tumor microenvironment. M1 macrophages typically exhibit anti-tumor properties by secreting pro-inflammatory cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), thereby enhancing the immune response. Conversely, M2 macrophages contribute to tumor cell migration and invasion through the production of factors like arginase-1 (Arg1) and interleukin-10 (IL-10). This review not only explores the diverse factors that affect macrophage polarization but also delves into the potential therapeutic strategies targeting macrophage polarization, including the critical roles of non-coding RNA and exosomes in regulating this process. The polarization state of macrophages is highlighted as a key determinant in PCa progression, offering a novel perspective for clinical treatment. Future research should concentrate on gaining a deeper understanding of the molecular mechanisms underlying macrophage polarization and on developing effective targeted therapeutic strategies. The exploration of the potential of combination therapies to improve treatment efficacy is also emphasized. By emphasizing the importance of macrophages as a therapeutic target in PCa, this review aims to provide valuable insights and research directions for clinicians and researchers.

The interplay between autophagy and ferroptosis presents a novel conceptual therapeutic framework for neuroendocrine prostate cancer

In American men, the incidence of prostate cancer (PC) is the highest among all types of cancer, making it the second leading cause of mortality associated with cancer. For advanced or metastatic PC, antiandrogen therapies are standard treatment options. The administration of these treatments unfortunately carries the potential risk of inducing neuroendocrine prostate cancer (NEPC). Neuroendocrine differentiation (NED) serves as a crucial indicator of prostate cancer development, encompassing various factors such as phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR), Yes-associated protein 1 (YAP1), AMP-activated protein kinase (AMPK), miRNA. The processes of autophagy and ferroptosis (an iron-dependent form of programmed cell death) play pivotal roles in the regulation of various types of cancers. Clinical trials and preclinical investigations have been conducted on many signaling pathways during the development of NEPC, with the deepening of research, autophagy and ferroptosis appear to be the potential target for regulating NEPC. Due to the dual nature of autophagy and ferroptosis in cancer, gaining a deeper understanding of the developmental programs associated with achieving autophagy and ferroptosis may enhance risk stratification and treatment efficacy for patients with NEPC.

Targeting Key Players of Neuroendocrine Differentiation in Prostate Cancer

Neuroendocrine prostate cancer (NEPC) is a highly aggressive subtype of prostate cancer (PC) that commonly emerges through a transdifferentiation process from prostate adenocarcinoma and evades conventional therapies. Extensive molecular research has revealed factors that drive lineage plasticity, uncovering novel therapeutic targets to be explored. A diverse array of targeting agents is currently under evaluation in pre-clinical and clinical studies with promising results in suppressing or reversing the neuroendocrine phenotype and inhibiting tumor growth and metastasis. This new knowledge has the potential to contribute to the development of novel therapeutic approaches that may enhance the clinical management and prognosis of this lethal disease. In the present review, we discuss molecular players involved in the neuroendocrine phenotype, and we explore therapeutic strategies that are currently under investigation for NEPC.

Novel biomarkers predict prognosis and drug-induced neuroendocrine differentiation in patients with prostate cancer

Background

A huge focus is being placed on the development of novel signatures in the form of new combinatorial regimens to distinguish the neuroendocrine (NE) characteristics from castration resistant prostate cancer (CRPC) timely and accurately, as well as predict the disease-free survival (DFS) and progression-free survival (PFS) of prostate cancer (PCa) patients.

Methods

Single cell data of 4 normal samples, 3 CRPC samples and 3 CRPC-NE samples were obtained from GEO database, and CellChatDB was used for potential intercellular communication, Secondly, using the "limma" package (v3.52.0), we obtained the differential expressed genes between CRPC and CRPC-NE both in single-cell RNA seq and bulk RNA seq samples, and discovered 12 differential genes characterized by CRPC-NE. Then, on the one hand, the diagnosis model of CRPC-NE is developed by random forest algorithm and artificial neural network (ANN) through Cbioportal database; On the other hand, using the data in Cbioportal and GEO database, the DFS and PFS prognostic model of PCa was established and verified through univariate Cox analysis, least absolute shrinkage and selection operator (Lasso) regression and multivariate Cox regression in R software. Finally, somatic mutation and immune infiltration were also discussed.

Results

Our research shows that there exists specific intercellular communication in classified clusters. Secondly, a CRPC-NE diagnostic model of six genes (HMGN2, MLLT11, SOX4, PCSK1N, RGS16 and PTMA) has been established and verified, the area under the ROC curve (AUC) is as high as 0.952 (95% CI: 0.882-0.994). The mutation landscape shows that these six genes are rarely mutated in the CRPC and NEPC samples. In addition, NE-DFS signature (STMN1 and PCSK1N) and NE-PFS signature (STMN1, UBE2S and HMGN2) are good predictors of DFS and PFS in PCa patients and better than other clinical features. Lastly, the infiltration levels of plasma cells, T cells CD4 naive, Eosinophils and Monocytes were significantly different between the CRPC and NEPC groups.

Conclusions

This study revealed the heterogeneity between CRPC and CRPC-NE from different perspectives, and developed a reliable diagnostic model of CRPC-NE and robust prognostic models for PCa.

TA-MSCs, TA-MSCs-EVs, MIF: their crosstalk in immunosuppressive tumor microenvironment

As an important component of the immunosuppressive tumor microenvironment (TME), it has been established that mesenchymal stem cells (MSCs) promote the progression of tumor cells. MSCs can directly promote the proliferation, migration, and invasion of tumor cells via cytokines and chemokines, as well as promote tumor progression by regulating the functions of anti-tumor immune and immunosuppressive cells. MSCs-derived extracellular vesicles (MSCs-EVs) contain part of the plasma membrane and signaling factors from MSCs; therefore, they display similar effects on tumors in the immunosuppressive TME. The tumor-promoting role of macrophage migration inhibitory factor (MIF) in the immunosuppressive TME has also been revealed. Interestingly, MIF exerts similar effects to those of MSCs in the immunosuppressive TME. In this review, we summarized the main effects and related mechanisms of tumor-associated MSCs (TA-MSCs), TA-MSCs-EVs, and MIF on tumors, and described their relationships. On this basis, we hypothesized that TA-MSCs-EVs, the MIF axis, and TA-MSCs form a positive feedback loop with tumor cells, influencing the occurrence and development of tumors. The functions of these three factors in the TME may undergo dynamic changes with tumor growth and continuously affect tumor development. This provides a new idea for the targeted treatment of tumors with EVs carrying MIF inhibitors.

The role of macrophage migration inhibitory factor in promoting benign prostatic hyperplasia epithelial cell growth by modulating COX-2 and P53 signaling

Inflammation and proinflammatory cytokines have been implicated in the progression of benign prostatic hyperplasia (BPH). Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine. Our previous study found that MIF is highly expressed in BPH epithelium. It has been reported that there is a correlation between MIF and clinical BPH progression. However, whether MIF has an effect on BPH epithelial cells is not clear. The aim of this study was to explore whether MIF has a role in BPH. Our results showed that immunohistochemistry (IHC) showed that MIF is highly expressed in the epithelium and that MIF and PCNA expression levels are higher in BPH samples than in control. CCK8 and flow cytometry assays showed that recombinant human MIF (rMIF) promoted the proliferation of BPH-1 and PWR-1E cells, while ISO-1 partially reversed this effect on proliferation. JC-1 assays showed that rMIF inhibited the apoptosis of BPH-1 and PWR-1E cells, and ISO-1 could partially reverse this inhibition. Moreover, western blotting indicated that rMIF downregulated P53 and upregulated COX-2. Furthermore, MIF-induced proliferation could be inhibited by celecoxib in the CCK8 and flow cytometry assay. MIF-inhibited apoptosis could be partially reversed by celecoxib in the JC-1 assay. Western blotting showed that celecoxib could partially reverse MIF-induced COX-2 upregulation and P53 downregulation. Together, MIF is highly expressed in BPH epithelium. In vitro, MIF promoted BPH epithelial cell growth by regulating COX-2 and P53 signaling. Targeting MIF may provide a new option for the improved treatment of BPH in the future.

Impact of the Dual Deletion of the Mitochondrial Sirtuins SIRT3 and SIRT5 on Anti-microbial Host Defenses

The sirtuins SIRT3 and SIRT5 are the main mitochondrial lysine deacetylase and desuccinylase, respectively. SIRT3 and SIRT5 regulate metabolism and redox homeostasis and have been involved in age-associated metabolic, neurologic and oncologic diseases. We have previously shown that single deficiency in either SIRT3 or SIRT5 had no impact on host defenses in a large panel of preclinical models of sepsis. However, SIRT3 and SIRT5 may compensate each other considering that they share subcellular location and targets. Here, we generated a SIRT3/5 double knockout mouse line. SIRT3/5 deficient mice multiplied and developed without abnormalities. Hematopoiesis and immune cell development were largely unaffected in SIRT3/5 deficient mice. Whole blood, macrophages and neutrophils from SIRT3/5 deficient mice displayed enhanced inflammatory and bactericidal responses. In agreement, SIRT3/5 deficient mice showed somewhat improved resistance to Listeria monocytogenes infection. Overall, the double deficiency in SIRT3 and SIRT5 has rather subtle impacts on immune cell development and anti-microbial host defenses unseen in single deficient mice, indicating a certain degree of overlap between SIRT3 and SIRT5. These data support the assumption that therapies directed against mitochondrial sirtuins, at least SIRT3 and SIRT5, should not impair antibacterial host defenses.

Expression of MIF, Beclin1, and LC3 in human salivary gland adenoid cystic carcinoma and its prognostic value

Adenoid cystic carcinoma (ACC) is an uncommon salivary gland malignancy with a poor long-term prognosis. Clinical reports show the high rates of local recurrences and distant metastases. This study aimed to investigate the expression of MIF, Beclin1, and light-chain 3 (LC3) in salivary adenoid cystic carcinoma (SACC).Tissue specimens were obtained from 48 salivary glands adenoid cystic carcinoma (SACC) patients and 15 oral squamous cell carcinoma (OSCC) patients. Immunohistochemical staining was performed to estimate the level of LC3, Beclin1, and MIF. All SACC patients were followed up. The Kaplan-Meier method was used to compare the prognosis of patients after treatment.The 3-year, 5 year-, and 10 year-survival rates of the SACC patients were 83.9%, 69.9%, and 46.6%, respectively. MIF, LC3, and Beclin1 in SACC were all obviously over-expressed. MIF showed an increased tendency in cases with advanced TNM stages, and at the same time, there was an inversely proportional relationship between MIF and LC3, Beclin1.The long-term survival of SACC patients is poor. MIF might be a risk factor for SACC patients, whereas, LC3 and Beclin1 might be an effective strategy for treatment of SACC.

Prostate cancer and inflammation: A new molecular imaging challenge in the era of personalized medicine

The relationship between cancer and inflammation is one of the most important fields for both clinical and translational research. Despite numerous studies reported interesting and solid data about the prognostic value of the presence of inflammatory infiltrate in cancers, the biological role of inflammation in prostate cancer development is not yet fully clarified. The characterization of molecular pathways that connect altered inflammatory response and prostate cancer progression can provide the scientific rationale for the identification of new prognostic and predictive biomarkers. Specifically, the detection of infiltrating immune cells or related-cytokines by histology and/or by molecular imaging techniques could profoundly change the management of prostate cancer patients. In this context, the anatomic pathology and imaging diagnostic teamwork can provide a valuable support for the validation of new targets for diagnosis and therapy of prostate cancer lesions associated to the inflammatory infiltrate. The aim of this review is to summarize the current literature about the role of molecular imaging technique and anatomic pathology in the study of the mutual interaction occurring between prostate cancer and inflammation. Specifically, we reported the more recent advances in molecular imaging and histological methods for the early detection of prostate lesions associated to the inflammatory infiltrate.

Sirtuin 5 Deficiency Does Not Compromise Innate Immune Responses to Bacterial Infections

Sirtuin 5 (SIRT5) is a member of the family of NAD⁺-dependent lysine/histone deacetylases. SIRT5 resides mainly in the mitochondria where it catalyzes deacetylation, demalonylation, desuccinylation, and deglutarylation of lysine to regulate metabolic and oxidative stress response pathways. Pharmacologic inhibitors of SIRT5 are under development for oncologic conditions, but nothing is known about the impact of SIRT5 on antimicrobial innate immune defenses. Using SIRT5 knockout mice, we show that SIRT5 deficiency does not affect immune cell development, cytokine production and proliferation by macrophages and splenocytes exposed to microbial and immunological stimuli. Moreover, preclinical models suggest that SIRT5 deficiency does not worsen endotoxemia, Klebsiella pneumoniae and Streptococcus pneumoniae pneumonia, Escherichia coli peritonitis, listeriosis, and staphylococcal infection. Altogether, these data support the safety profile in terms of susceptibility to infections of SIRT5 inhibitors under development.

Plasma androgen receptor and serum chromogranin A in advanced prostate cancer

Recently, mixed forms between adenocarcinoma and neuroendocrine prostate cancer (NEPC) have emerged that are characterized by persistent androgen receptor (AR)-signalling and elevated chromogranin A (CgA) levels. The main aim of this study was to analyze castration-resistant prostate cancer (CRPC) patients treated with abiraterone or enzalutamide, assessing progression-free/overall survival (PFS/OS) in association with circulating AR and CgA. AR aberrations were analyzed by droplet digital PCR in pre-treatment plasma samples collected from two biomarker protocols [197 patients from a retrospective study (REC 2192/2013) and 59 from a prospective trial (REC 6798/2015)]. We subdivided patients into three groups according to CgA by receiver-operating characteristic (ROC) curves. In the primary cohort, plasma AR gain and mutations (p.L702H/p.T878A) were detected in 78 (39.6%) and 16 (8.1%) patients, respectively. We observed a significantly worse PFS/OS in patients with higher-CgA than in patients with normal-CgA, especially those with no AR-aberrations. Multivariable analysis showed AR gain, higher-CgA and LDH levels as independent predictors of PFS [hazard ratio (HR) = 2.16, 95% confidence interval (95% CI) 1.50-3.12, p < 0.0001, HR = 1.73, 95% CI 1.06-2.84, p = 0.026, and HR = 2.13, 95% CI 1.45-3.13, p = 0.0001, respectively) and OS (HR = 1.72, 95% CI 1.15-2.57, p = 0.008, HR = 3.63, 95% CI 2.13-6.20, p < 0.0001, and HR = 2.31, 95% CI 1.54-3.48, p < 0.0001, respectively). These data were confirmed in the secondary cohort. Pre-treatment CgA detection could be useful to identify these mixed tumors and would seem to have a prognostic role, especially in AR-normal patients. This association needs further evaluation in larger prospective cohorts.

ADT with antiandrogens in prostate cancer induces adverse effect of increasing resistance, neuroendocrine differentiation and tumor metastasis

Prostate cancer (PCa) is the most common cancer and the 2nd leading cause of cancer-related deaths among men in the United States. Androgen-deprivation-therapy (ADT) with antiandrogens to target the androgens/androgen receptor (AR) signals remains the standard therapy for advanced PCa. However, most of the PCa patients who received ADT with antiandrogens, including the recently developed Enzalutamide (Enz) that might extend PCa patients survival an extra 4.8 months, will still develop the castration (or antiandrogen) resistance. Mechanism dissection studies suggest these antiandrogen resistances may involve the induction of AR splicing variants and/or AR mutants. Further preclinical in vitro/in vivo studies suggest ADT-antiandrogens may also enhance the neuroendocrine differentiation (NED) and PCa cell invasion, and these unwanted side-effects may function through various mechanisms including altering the infiltrating inflammatory cells within the prostate tumor microenvironment. This review summarizes these unwanted ADT-induced side-effects and discusses multiple approaches to overcome these side-effects to better suppress the PCa at the castration resistant stage.

Evaluation of prothrombin induced by vitamin K absence, macrophage migration inhibitory factor and Golgi protein-73 versus alpha fetoprotein for hepatocellular carcinoma diagnosis and surveillance

Hepatocellular carcinoma (HCC) represents a challenging malignancy of worldwide importance. It is the third most common cause of cancer-related death globally as most patients present with unresectable disease. Alpha-fetoprotein (AFP) is the widely and solely used biomarker for HCC diagnosis; yet, its usefulness is hampered by low sensitivity and specificity. We aimed to identify more sensitive biomarkers for HCC diagnosis and a surveillance algorithm that may facilitate early detection of HCC. A total of 305 Egyptian and Saudi participants grouped as healthy controls, cancer controls, benign hepatic lesions, chronic viral hepatitis and HCC were included. Serum AFP, prothrombin induced by vitamin K absence-II (PIVKA-II), macrophage migration inhibitory factor (MIF) and Golgi protein-73 (GP-73) levels were quantitated by enzyme immunoassay. Significantly higher levels of GP-73 and PIVKA-II were detected in the HCC group than in all other groups, while MIF showed a highly significant increase in HCC from all groups except the cancer control group. The HCC group showed no significant difference between the studied biomarkers and the type of chronic viral hepatitis. On the basis of multiple ROC curve analyses, GP-73 and PIVKA-II showed the highest sensitivity and specificity for surveillance and diagnosis. In conclusion, PIVKA-II and GP-73 offer an effective approach for early HCC diagnosis and surveillance of high-risk groups with a higher accuracy than AFP. MIF may serve as a promising screening tumor marker for the detection of gastrointestinal tract (GIT) malignancy.

Impact of the microbial derived short chain fatty acid propionate on host susceptibility to bacterial and fungal infections in vivo

Short chain fatty acids (SCFAs) produced by intestinal microbes mediate anti-inflammatory effects, but whether they impact on antimicrobial host defenses remains largely unknown. This is of particular concern in light of the attractiveness of developing SCFA-mediated therapies and considering that SCFAs work as inhibitors of histone deacetylases which are known to interfere with host defenses. Here we show that propionate, one of the main SCFAs, dampens the response of innate immune cells to microbial stimulation, inhibiting cytokine and NO production by mouse or human monocytes/macrophages, splenocytes, whole blood and, less efficiently, dendritic cells. In proof of concept studies, propionate neither improved nor worsened morbidity and mortality parameters in models of endotoxemia and infections induced by gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae), gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae) and Candida albicans. Moreover, propionate did not impair the efficacy of passive immunization and natural immunization. Therefore, propionate has no significant impact on host susceptibility to infections and the establishment of protective anti-bacterial responses. These data support the safety of propionate-based therapies, either via direct supplementation or via the diet/microbiota, to treat non-infectious inflammation-related disorders, without increasing the risk of infection.

Prognostic value of inflammation in prostate cancer progression and response to therapeutic: a critical review

Prostate is an immune-competent organ normally populated by inflammatory cells. Prostatic inflammation origin can be multi-factorial and there are some emerging evidences on its possible role as a factor involved in prostate cancer (PC) pathogenesis and progression. This review critically analyzes the role of inflammation as a prognostic factor for progression and aggressiveness of PC. We verified the last 10 years literature data on the association between inflammation and PC aggressiveness, or PC response to therapies. Several studies tried to correlate different inflammatory factors with the aggressiveness and metastatization of PC; all data sustain the role of inflammation in PC progression but they also produce confusion to identify a reliable clinical prognostic marker. Data on patients submitted to radical prostatectomy (RP) showed that cases with marked intraprostatic tissue inflammation are associated with higher rate of biochemical progression; systemic inflammation markers appear to have a significant prognostic value. Analyzing data on patients submitted to radiotherapy (RT) emerges a significant association between high neuthrophil to lymphocyte ratio (NLR) and decreased progression free survival and overall survival; also plateled to lymphocyte ratio (PLR) and C-reactive protein (CRP) have been proposed as significant prognostic factors for progression and overall survival. In patients submitted to androgen deprivation therapy (ADT), inflammation may drive castration resistant PC (CRPC) development by activation of STAT3 in PC cells. NLR has been proposed as independent predictor of overall survival in CRPC submitted to chemotherapy. Most of data are focused on markers related to systemic inflammation such as NLR and CRP, more than specifically to chronic prostatic inflammation. The suggestion is that these inflammatory parameters, also if not specific for prostatic inflammation and possibly influenced by several factors other than PC, can integrate with established prognostic factors.

Intracellular Elemental Patterns of Apoptosis Resistance in Transdifferentiated Androgen-Dependent Prostatic Carcinoma Cells

The acquisition of neuroendocrine (NE) characteristics by prostate cancer (PC) cells relates to tumor progression and hormone resistance. PC cells may survive and function in androgen-deprived environments, where they could establish paracrine signaling networks, providing stimuli for the propagation of local carcinoma cells. We previously demonstrated, using electron probe X-ray microanalysis (EPXMA), in LNCaP, PC-3, and Du 145 cell lines that apoptosis is associated with intracellular elemental changes, and that the NE secretory products, bombesin and calcitonin, inhibit etoposide-induced apoptosis, as well as some of these elemental changes. In this study, LNCaP cells were induced in vitro to transdifferentiate under androgen deprivation, to mimic the role of NE cells in the apoptotic activity of transdifferentiated androgen-dependent PC cells. Changes in intracellular ion content associated with apoptosis, assessed by EPXMA, demonstrate that the transdifferentiated LNCaP cells are resistant to etoposide-induced apoptosis and also to the etoposide-induced elemental changes. The aggressive malignant potential of PC with neuroendocrine differentiation, associated with hormonal independence, is partly because of the ability that most NE tumor cells have to escape apoptosis, which can enhance the malignant properties of tumor cells and may have therapeutic implications as tumor cells are usually resistant to cytotoxic drugs as etoposide.

Prognostic Value of the Pretreatment Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio for Patients with Neuroendocrine Tumors: An Izmir Oncology Group Study

BACKGROUND

Several studies evaluating the prognostic factors of gastrointestinal and pancreatic neuroendocrine tumors (GEP-NETs) have been published. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have been accepted as prognostic factors for cancer patients.

MATERIALS AND METHODS

This study included 132 patients diagnosed with GEP-NETs. Peripheral blood samples were collected before the pretreatment period.

RESULTS

NLR and PLR were increased as the grade increased in NETs. The embryonic origin analysis revealed higher NLR and PLR rates in NETs of foregut origin. NLR and PLR were also higher in pancreatic NET patients compared to the gastroenteric NET patients. Analysis of NETs by TNM indicated that an advanced stage was accompanied by significantly higher NLR and PLR. We found a strong negative correlation between progression-free survival and NLR and PLR.

CONCLUSION

The study verified that NLR and PLR are simple laboratory findings that can be used to identify NETs with a worse outcome.

Anti-androgen enzalutamide enhances prostate cancer neuroendocrine (NE) differentiation via altering the infiltrated mast cells → androgen receptor (AR) → miRNA32 signals

The recently developed anti-androgen enzalutamide also known as (MDV3100) has the advantage to prolong by 4.8 months the survival of castration resistant prostate cancer (CRPC) patients. However, the mechanisms behind the potential side effects involving the induction of the prostate cancer (PCa) neuroendocrine (NE) differentiation remain unclear. Here we found PCa cells could recruit more mast cells than normal prostate epithelial cells, and enzalutamide (or casodex) treatment could further increase such recruitment that resulted in promoting the PCa NE differentiation. Mechanism dissection found infiltrated mast cells could function through positive feedback to enhance PCa to recruit more mast cells via modulation of the androgen receptor (AR) → cytokines IL8 signals, and interruption by AR-siRNA or neutralizing anti-IL8 antibody could partially reverse the recruitment of mast cells. Importantly, targeting the PCa androgens/AR signals with AR-siRNA or enzalutamide (or casodex) also increased PCa NE differentiation via modulation of the miRNA32 expression, and adding miRNA32 inhibitor reversed the AR-siRNA- or enzalutamide-enhanced NE differentiation. Together, these results not only identified a new signal via infiltrated mast cells → PCa AR → miRNA32 to increase PCa NE differentiation, it also pointed out the potential unwanted side effects of enzalutamide (or casodex) to increase PCa NE differentiation. Targeting these newly identified signals, including AR, IL8, or miRNA32, may help us to better suppress PCa NE differentiation that is induced during ADT with anti-androgen enzalutamide (or casodex) treatment.

Multiple binding modes of isothiocyanates that inhibit macrophage migration inhibitory factor

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has roles in the innate immune response, and also contributes to inflammatory disease. While the biological properties of MIF are closely linked to protein-protein interactions, MIF also has tautomerase activity. Inhibition of this activity interferes with the interaction of MIF with protein partners e.g. the CD74 receptor, and tautomerase inhibitors show promise in disease models including multiple sclerosis and colitis. Isothiocyanates inhibit MIF tautomerase activity via covalent modification of the N-terminal proline. We systematically explored variants of benzyl and phenethyl isothiocyanates, to define determinants of inhibition. In particular, substitution with hydroxyl, chloro, fluoro and trifluoro moieties at the para and meta positions were evaluated. In assays on treated cells and recombinant protein, the IC50 varied from 250 nM to >100 μM. X-ray crystal structures of selected complexes revealed that two binding modes are accessed by some compounds, perhaps owing to strain in short linkers between the isothiocyanate and aromatic ring. The variety of binding modes confirms the existence of two subsites for inhibitors and establishes a platform for the development of potent inhibitors of MIF that only need to target one of these subsites.

Targeting neuroendocrine prostate cancer: molecular and clinical perspectives

Neuroendocrine prostate carcinoma, either co-present with the local adenocarcinoma disease or as a result of transdifferentiation later in time, was described as one major process of emerging resistance to androgen deprivation therapies, and at the clinical level it is consistent with the development of rapidly progressive visceral disease, often in the absence of elevated serum prostate-specific antigen level. Until present, platinum-based chemotherapy has been the only treatment modality, able to produce a fair amount of responses but of short duration. Recently, several efforts for molecular characterization of this lethal phenotype have resulted in identification of novel signaling factors involved in microenvironment interactions, mitosis, and neural reprograming as potential therapeutic targets. Ongoing clinical testing of specific inhibitors of these targets, for example, Aurora kinase A inhibitors, in carefully selected patients and exploitation of expression changes of the target before and after manipulation is anticipated to increase the existing data and facilitate therapeutic decision making at this late stage of the disease when hormonal manipulations, even with the newest androgen-directed therapies are no longer feasible.

Innate Immune Sensing of Fusarium culmorum by Mouse Dendritic Cells

Chronic inhalation of grain dust is associated with asthma and chronic bronchitis in grain worker populations. Exposure to fungal particles was postulated to be an important etiologic agent of these pathologies. Fusarium species frequently colonize grain and straw and produce a wide array of mycotoxins that impact human health, necessitating an evaluation of risk exposure by inhalation of Fusarium and its consequences on immune responses. Data showed that Fusarium culmorum is a frequent constituent of aerosols sampled during wheat harvesting in the Vaud region of Switzerland. The aim of this study was to examine cytokine/chemokine responses and innate immune sensing of F. culmorum in bone-marrow-derived dendritic cells and macrophages. Overall, dendritic cells and macrophages responded to F. culmorum spores but not to its secreted components (i.e., mycotoxins) by releasing large amounts of macrophage inflammatory protein (MIP)-1α, MIP-1β, MIP-2, monocyte chemoattractant protein (MCP)-1, RANTES, and interleukin (IL)-12p40, intermediate amounts of tumor necrosis factor (TNF), IL-6, IL-12p70, IL-33, granulocyte colony-stimulating factor (G-CSF), and interferon gamma-induced protein (IP-10), but no detectable amounts of IL-4 and IL-10, a pattern of mediators compatible with generation of Th1 or Th17 antifungal protective immune responses rather than with Th2-dependent allergic responses. The sensing of F. culmorum spores by dendritic cells required dectin-1, the main pattern recognition receptor involved in β-glucans detection, but likely not MyD88 and TRIF-dependent Toll-like receptors. Taken together, our results indicate that F. culmorum stimulates potently innate immune cells in a dectin-1-dependent manner, suggesting that inhalation of F. culmorum from grain dust may promote immune-related airway diseases in exposed worker populations.

Trichomonas vaginalis homolog of macrophage migration inhibitory factor induces prostate cell growth, invasiveness, and inflammatory responses

The human-infective parasite Trichomonas vaginalis causes the most prevalent nonviral sexually transmitted infection worldwide. Infections in men may result in colonization of the prostate and are correlated with increased risk of aggressive prostate cancer. We have found that T. vaginalis secretes a protein, T. vaginalis macrophage migration inhibitory factor (TvMIF), that is 47% similar to human macrophage migration inhibitory factor (HuMIF), a proinflammatory cytokine. Because HuMIF is reported to be elevated in prostate cancer and inflammation plays an important role in the initiation and progression of cancers, we have explored a role for TvMIF in prostate cancer. Here, we show that TvMIF has tautomerase activity, inhibits macrophage migration, and is proinflammatory. We also demonstrate that TvMIF binds the human CD74 MIF receptor with high affinity, comparable to that of HuMIF, which triggers activation of ERK, Akt, and Bcl-2-associated death promoter phosphorylation at a physiologically relevant concentration (1 ng/mL, 80 pM). TvMIF increases the in vitro growth and invasion through Matrigel of benign and prostate cancer cells. Sera from patients infected with T. vaginalis are reactive to TvMIF, especially in males. The presence of anti-TvMIF antibodies indicates that TvMIF is released by the parasite and elicits host immune responses during infection. Together, these data indicate that chronic T. vaginalis infections may result in TvMIF-driven inflammation and cell proliferation, thus triggering pathways that contribute to the promotion and progression of prostate cancer.

Hallmarks of gastrointestinal neuroendocrine tumours: implications for treatment

In the past few years, there have been advances in the treatment of neuroendocrine tumours (NETs) and improvements in our understanding of NET biology. However, the benefits to patients have been relatively modest and much remains yet to be done. The 'Hallmarks of Cancer', as defined by Hanahan and Weinberg, provide a conceptual framework for understanding the aberrations that underlie tumourigenesis and to help identify potential targets for therapy. In this study, our objective is to review the major molecular characteristics of NETs, based on the recently modified 'Hallmarks of Cancer', and highlight areas that require further research.

Macrophage migratory inhibitory factor promotes bladder cancer progression via increasing proliferation and angiogenesis

Macrophage migratory inhibitory factor (MIF) is a proinflammatory cytokine shown to promote tumorigenesis. Using the N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) model of bladder cancer, we previously showed that MIF knockout mice display decreased angiogenesis and invasion compared with wild-type. This study examines the role of MIF in bladder cancer via use of oral inhibitors of MIF. In vitro, high-grade bladder cancer cells were treated with recombinant human MIF +/- (rhMIF+/-) inhibitor. Measurements included cell counts, proliferation by (3)H-thymidine incorporation (TdR), extracellular signal-regulated kinase (ERK) phosphorylation by western blot analysis, messenger RNA (mRNA) expression by quantitative PCR and protein secretion by enzyme-linked immunosorbent assay. Treatment with rhMIF increased ERK phosphorylation, cell counts, TdR and mRNA expression and protein secretion of vascular endothelial growth factor, which were blocked by specific inhibitors of ERK and MIF. In vivo, 3-month-old male C57Bl/6 mice were given BBN for 22 and 16 weeks in study 1 and study 2, respectively. Mice (n = 8-10 per group) were gavaged with vehicle or doses of MIF inhibitors daily from weeks 16-22 in both studies. Average bladder weights, reflecting tumor mass, tumor stage/burden, mitotic rate and proliferation indices, and microvessel densities were reduced in inhibitor groups versus controls. In summary, MIF promotes bladder cancer via increasing cell proliferation and angiogenesis and oral inhibitors of MIF may prove useful in treatment of this disease.

Influence of a six month endurance exercise program on the immune function of prostate cancer patients undergoing Antiandrogen- or Chemotherapy: design and rationale of the ProImmun study

BACKGROUND

Exercise seems to minimize prostate cancer specific mortality risk and treatment related side effects like fatigue and incontinence. However the influence of physical activity on the immunological level remains uncertain. Even prostate cancer patients undergoing palliative treatment often have a relatively long life span compared to other cancer entities. To optimize exercise programs and their outcomes it is essential to investigate the underlying mechanisms. Further, it is important to discriminate between different exercise protocols and therapy regimes.

METHODS/DESIGN

The ProImmun study is a prospective multicenter patient preference randomized controlled trial investigating the influence of a 24 week endurance exercise program in 80-100 prostate cancer patients by comparing patients undergoing Antiandrogen therapy combined with exercise (AE), Antiandrogen therapy without exercise (A), Chemotherapy with exercise(CE) or Chemotherapy without exercise (C). The primary outcome of the study is a change in prostate cancer relevant cytokines and hormones (IL-6, MIF, IGF-1, Testosterone). Secondary endpoints are immune cell ratios, oxidative stress and antioxidative capacity levels, VO2 peak, fatigue and quality of life. Patients of the intervention group exercise five times per week, while two sessions are supervised. During the supervised sessions patients (AE and CE) exercise for 33 minutes on a bicycle ergometer at 70-75% of their VO2 peak. To assess long term effects and sustainability of the intervention two follow-up assessments are arranged 12 and 18 month after the intervention.

DISCUSSION

The ProImmun study is the first trial which primarily investigates immunological effects of a six month endurance exercise program in prostate cancer patients during palliative care. Separating patients treated with Antiandrogen therapy from those who are additionally treated with Chemotherapy might allow a more specific view on the influence of endurance training interventions and the impact of different therapy protocols on the immune function.

TRIAL REGISTRATION

German Clinical Trials Register: DRKS00004739.

Linking inflammation and neuroendocrine differentiation: the role of macrophage migration inhibitory factor-mediated signaling in prostate cancer

A new paper by Tawadros et al. in Endocrine-Related Cancer demonstrates a link between macrophage migration inhibitory factor and neuroendocrine differentiation in prostate cancer. This paper may have implications in explaining the effect of prostatitis and chronic inflammation on the development of aggressive prostate cancer.