Association between tumor-associated macrophages and microvessel density on prostate cancer progression

Correlation analysis of bone marrow microvessel density and miRNA expression on drug resistance in patients with chronic myelogenous leukemia after tyrosine kinase inhibitor treatment

OBJECTIVE

This study analyzed the relationship between bone marrow microvessel density (MVD) and the expression of four miRNAs with chronic myelogenous leukemia (CML) resistance after tyrosine kinase inhibitor (TKI) treatment.

METHODS

234 CML patients were divided into resistance and non-resistance groups in terms of the results of the 5-year follow-up. Patients were divided into the Optimum response group and the Warning/Failure group based on TKI response. MVD was determined by immunohistochemistry, and the expression levels of four miRNAs (miR-106a, miR-155, miR-146a, and miR-340) in bone marrow biopsy specimens were examined by qPCR. We evaluated the association of MVD with four miRNAs and them predictive value for CML resistance after TKI treatment.

RESULTS

The MVD and the levels of miR-106a, miR-155, and miR-146a were significantly higher while the miR-340 level was lower in the resistance group than the non-resistance group. Besides, MVD had a significant correlation with the levels of miR-340 and miR-155. According to the results of survival analysis, MVD as well as miR-340 and miR-155 levels were observably correlated with 5-year survival of patients without TKI resistance. The results of the ROC curve indicated that the MVD, miR-106a, miR-340, and miR-155 had good predictive accuracy for CML resistance after TKI treatment. As for the results of multivariate analysis, disease stage, risk level (high risk), high MVD, low miR-340 expression, and high miR-155 expression were all independent risk factors for CML resistance.

CONCLUSION

MVD and the expression of miR-340 and miR-155 are closely associated with CML resistance after TKI treatment.

An 18-gene signature of recurrence-associated endothelial cells predicts tumor progression and castration resistance in prostate cancer

BACKGROUND

The prognostic and therapeutic implications of endothelial cells (ECs) heterogeneity in prostate cancer (PCa) are poorly understood.

METHODS

We investigated associations of EC heterogeneity with PCa recurrence and castration resistance in 8 bulk transcriptomic and 4 single-cell RNA-seq cohorts. A recurrence-associated EC (RAEC) signature was constructed by comparing 11 machine learning algorithms through nested cross-validation. Functional relevances of RAEC-specific genes were also tested.

RESULTS

A subset of ECs was significantly associated with recurrence in primary PCa and named RAECs. RAECs were characteristic of tip and immature cells and were enriched in migration, angiogenesis, and collagen-related pathways. We then developed an 18-gene RAEC signature (RAECsig) representative of RAECs. Higher RAECsig scores independently predicted tumor recurrence and performed better or comparably compared to clinicopathological factors and commercial gene signatures in multiple PCa cohorts. Of the 18 RAECsig genes, FSCN1 was upregulated in ECs from PCa with higher Gleason scores; and the silencing of FSCN1, TMEME255B, or GABRD in ECs either attenuated tube formation or inhibited PCa cell proliferation. Finally, higher RAECsig scores predicted castration resistance in both primary and castration-resistant PCa.

CONCLUSION

This study establishes an endothelial signature that links a subset of ECs to prostate cancer recurrence and castration resistance.

Targeting endothelial permeability in the EPR effect

The characteristics of the primary tumor blood vessels and the tumor microenvironment drive the enhanced permeability and retention (EPR) effect, which confers an advantage towards enhanced delivery of anti-cancer nanomedicine and has shown beneficial effects in preclinical models. Increased vascular permeability is a landmark feature of the tumor vessels and an important driver of the EPR. The main focus of this review is the endothelial regulation of vascular permeability. We discuss current challenges of targeting vascular permeability towards clinical translation and summarize the structural components and mechanisms of endothelial permeability, the principal mediators and signaling players, the targeted approaches that have been used and their outcomes to date. We also critically discuss the effects of the tumor-infiltrating immune cells, their interplay with the tumor vessels and the impact of immune responses on nanomedicine delivery, the impact of anti-angiogenic and tumor-stroma targeting approaches, and desirable nanoparticle design approaches for greater translational benefit.

Prostate tumor RON receptor signaling mediates macrophage recruitment to drive androgen deprivation therapy resistance through Gas6-mediated Axl and RON signaling

BACKGROUND

Androgen deprivation therapy (ADT), or chemical castration, is the first-line therapy for prostate cancer; however, resistance leaves few treatment options. Prostatic tumor-associated macrophages (TAMs) have been shown to promote prostate cancer growth and are abundant in castration-resistant prostate cancer (CRPC), suggesting a role in promoting CRPC. We recently showed a tumor cell-intrinsic mechanism by which RON promotes CRPC. Given previous reports that RON alters prostate cancer cell chemokine production and RON-overexpressing tumors alter macrophage function, we hypothesized that a macrophage-dependent mechanism regulated by tumor cell intrinsic RON also promotes CRPC.

METHODS

Using RON-modulated genetically engineered mouse models (GEMMs) and GEMM-derived cell lines and co-cultures with bone marrow-derived macrophages, we show functional and molecular characteristics of signaling pathways in supporting CRPC. Further, we used an unbiased phosphokinase array to identify pathway interactions regulated by RON. Finally, using human prostate cancer cell lines and prostate cancer patient data sets, we show the relevance of our findings to human prostate cancer.

RESULTS

Studies herein show that macrophages recruited into the prostate tumor microenvironment (TME) serve as a source for Gas6 secretion which serves to further enhance RON and Axl receptor activation in prostate tumor cells thereby driving CRPC. Further, we show targeting RON and macrophages in a murine model promotes CRPC sensitization to ADT.

CONCLUSIONS

We discovered a novel role for the RON receptor in prostate cancer cells in promoting CRPC through the recruitment of macrophages into the prostate TME. Macrophage-targeting agents in combination with RON/Axl inhibition are likely to provide clinical benefits for patients with CRPC.

The role of tumor-associated macrophages (TAMs) in tumor progression and relevant advance in targeted therapy

Macrophages have a leading position in the tumor microenvironment (TME) which paves the way to carcinogenesis. Initially, monocytes and macrophages are recruited to the sites where the tumor develops. Under the guidance of different microenvironmental signals, macrophages would polarize into two functional phenotypes, named as classically activated macrophages (M1) and alternatively activated macrophages (M2). Contrary to the anti-tumor effect of M1, M2 exerts anti-inflammatory and tumorigenic characters. In progressive tumor, M2 tumor-associated macrophages (TAMs) are in the majority, being vital regulators reacting upon TME. This review elaborates on the role of TAMs in tumor progression. Furthermore, prospective macrophage-focused therapeutic strategies, including drugs not only in clinical trials but also at primary research stages, are summarized followed by a discussion about their clinical application values. Nanoparticulate systems with efficient drug delivery and improved antitumor effect are also summed up in this article.

Androgen receptor signalling in macrophages promotes TREM-1-mediated prostate cancer cell line migration and invasion

The androgen receptor (AR) is the master regulator of prostate cancer (PCa) development, and inhibition of AR signalling is the most effective PCa treatment. AR is expressed in PCa cells and also in the PCa-associated stroma, including infiltrating macrophages. Macrophages have a decisive function in PCa initiation and progression, but the role of AR in macrophages remains largely unexplored. Here, we show that AR signalling in the macrophage-like THP-1 cell line supports PCa cell line migration and invasion in culture via increased Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) signalling and expression of its downstream cytokines. Moreover, AR signalling in THP-1 and monocyte-derived macrophages upregulates IL-10 and markers of tissue residency. In conclusion, our data suggest that AR signalling in macrophages may support PCa invasiveness, and blocking this process may constitute one mechanism of anti-androgen therapy.

Anti-androgen therapy inhibits prostate cancer (PC) progression, and is thought to act directly on cancer cells. Here the authors show that androgen receptor is expressed on normal and PC-associated macrophages, and its stimulation alters macrophage secretome to promote migration of cultured PC cell lines.

Increased tumor-associated macrophages in the prostate cancer microenvironment predicted patients' survival and responses to androgen deprivation therapies in Indonesian patients cohort

BACKGROUND

Tumor-associated macrophages (TAMs) and microvessel density (MVD) play an essential role for tumor progression in prostate cancer (PCa). In this study, we evaluated the association between TAMs, the infiltration with tumor angiogenesis and the response to androgen deprivation therapies (ADTs) in PCa to evaluate TAM infiltration as a predictive factor for PCa survival.

MATERIALS AND METHODS

Fifty-four specimens were collected and stained with CD 68 antibody to investigated TAM infiltration in tumor. Von Willebrand factor was stained to evaluate MVD around the cancer foci. We assessed the association between patient's age, preoperative serum prostate-specific antigen, pathologic Gleason sum (GS), TAM infiltration, MVD, and the response to ADT for 5 years after PCa diagnosis.

RESULTS

The median TAM was observed in 28 (6-76)/high power field (x400). Increasing TAM correlated with increasing tumor angiogenesis (P < 0.001, r = 0.61), and the response to ADT was significantly better in patients with fewer TAMs (<28) than in patients with higher TAMs (>28) (P = 0.003). TAM infiltration was significantly higher in those with higher serum prostate-specific antigen, higher GS, and metastasis. Multivariate analysis showed that GS, ADT type, and MVD number were significant prognostic factors for response to ADT in PCa (P < 0.0001). An increased infiltration of TAM [hazards ratio (HR) = 4.47; 95% confidence interval (CI): 1.97-10.15], MVD (HR = 2.66; 95% CI: 1.27-5.61), metastatic status (HR = 2.29; 95% CI: 0.14-0.60), and prostate volume (HR = 2.19; 95% CI: 1.27-3.12) significantly correlated with shorter survival in PCa patients by univariate analysis (P < 0.05). Multivariate analyses revealed that TAM and metastatic status significantly correlated with poor overall survival.

CONCLUSIONS

TAM infiltration is associated with response to ADT and increased tumor angiogenesis in PCa. GS, ADT type, and MVD in PCa specimens are useful predictive factors for poor response to ADT. Increasing TAM and positive metastatic status were prognostic factors for a poorer survival in PCa patients.

Leucine Zipper-EF-Hand Containing Transmembrane Protein 1 Is a Potential Prognostic Biomarker and Promotes Cell Progression in Prostate Cancer

Purpose

The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is a mitochondrial protein that has been associated with the occurrence and development of malignant tumors. Previous studies have shown that LETM1 expression is increased in several types of human cancer and is associated with a poor clinical outcome. However, the role of LETM1 in prostate cancer (PCa) has not yet been determined. In this study, we investigated the clinicopathological significance of LETM1 expression and its role in PCa progression.

Methods

We assessed the expression of LETM1 and genes related to cancer stemness, epithelial-mesenchymal transition (EMT), cell cycle, and PI3K/Akt signaling in 133 paraffin-embedded PCa tissue samples and cancer cells by using immunohistochemistry, immunofluorescence, and Western blotting.

Results

LETM1 expression was significantly increased in PCa, and it was positively correlated with Gleason score, pathologic tumor (pT) stage, clinical stage, and high microvessel density. Survival analysis showed that patients with PCa with a high level of LETM1 expression exhibited a low overall survival. Cox regression analysis indicated that LETM1 is an independent poor prognostic PCa factor. Additionally, the expression of LETM1 was correlated with cancer cell stemness-associated genes, EMT-related genes, cell cycle regulatory genes, and PI3K/Akt signaling gene expression in PCa. Furthermore, knocking down LETM1 expression down-regulated the expression of stemness-related proteins, while inhibiting tumor spheroid formation, EMT-like changes, cell proliferation, migration, and invasion in PCa cells. Importantly, the PI3K inhibitor LY294002 strongly inhibited the expression of LETM1, pPI3K-p85, and pAkt (Thr308, Ser473) in PCa cells.

Conclusion

These results indicate that LETM1 expression is associated with cancer cell stemness, promotes EMT-like changes and cell proliferation and is a potential prognostic biomarker for PCa.

Dynamic Contrast-Enhanced Imaging as a Prognostic Tool in Early Diagnosis of Prostate Cancer: Correlation with PSA and Clinical Stage

Background and Purpose

Although several methods have been developed to predict the outcome of patients with prostate cancer, early diagnosis of individual patient remains challenging. The aim of the present study was to correlate tumor perfusion parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and clinical prognostic factors and further to explore the diagnostic value of DCE-MRI parameters in early stage prostate cancer.

Patients and Methods

Sixty-two newly diagnosed patients with histologically proven prostate adenocarcinoma were enrolled in our prospective study. Transrectal ultrasound-guided biopsy (12 cores, 6 on each lobe) was performed in each patient. Pathology was reviewed and graded according to the Gleason system. DCE-MRI was performed and analyzed using a two-compartmental model; quantitative parameters including volume transfer constant (K^trans), reflux constant (K_ep), and initial area under curve (iAUC) were calculated from the tumors and correlated with prostate-specific antigen (PSA), Gleason score, and clinical stage.

Results

K^trans (0.11 ± 0.02 min⁻¹ versus 0.16 ± 0.06 min⁻¹; p < 0.05), K_ep (0.38 ± 0.08 min⁻¹ versus 0.60 ± 0.23 min⁻¹; p < 0.01), and iAUC (14.33 ± 2.66 mmoL/L/min versus 17.40 ± 5.97 mmoL/L/min; p < 0.05) were all lower in the clinical stage T1c tumors (tumor number, n=11) than that of tumors in clinical stage T2 (n=58). Serum PSA correlated with both tumor K^trans (r=0.304, p < 0.05) and iAUC (r=0.258, p < 0.05).

Conclusions

Our study has confirmed that DCE-MRI is a promising biomarker that reflects the microcirculation of prostate cancer. DCE-MRI in combination with clinical prognostic factors may provide an effective new tool for the basis of early diagnosis and treatment decisions.

Elevation of Stromal-Derived Mediators of Inflammation Promote Prostate Cancer Progression in African-American Men

Progress in prostate cancer racial disparity research has been hampered by a lack of appropriate research tools and better understanding of the tumor biology. Recent gene expression studies suggest that the tumor microenvironment (TME) may contribute to racially disparate clinical outcomes in prostate cancer. Analysis of the prostate TME has shown increased reactive stroma associated with chronic inflammatory infiltrates in African-American (AA) compared with European-American (EA) patients with prostate cancer. To better understand stromal drivers of changes in TME, we isolated prostate fibroblasts (PrF) from AA (PrF^-AA) and EA (PrF^-EA) prostate cancer tissues and studied their functional characteristics. PrF^-AA showed increased growth response to androgens FGF2 and platelet-derived growth factor. Compared with PrF^-EA, conditioned media from PrF^-AA significantly enhanced the proliferation and motility of prostate cancer cell lines. Expression of markers associated with myofibroblast activation (αSMA, vimentin, and tenascin-C) was elevated in PrF^-AA In vivo tumorigenicity of an AA patient-derived prostatic epithelial cell line E006AA was significantly increased in the presence of PrF^-AA compared with PrF^-EA, and RNA-seq data and cytokine array analysis identified a panel of potential proinflammatory paracrine mediators (BDNF, CHI3L1, DPPIV, FGF7, IL18BP, IL6, and VEGF) to be enriched in PrF^-AA E006AA cell lines showed increased responsiveness to BDNF ligand compared with EA-derived LNCaP and C4-2B cells. Addition of a TrkB-specific antagonist significantly reduced the protumorigenic effects induced by PrF^-AA compared with PrF^-EA These findings suggest that fibroblasts in the TME of AA patients may contribute to the health disparity observed in the incidence and progression of prostate cancer tumors.Significance: These findings suggest that stromal cells in the tumor microenvironment of African-American men promote progression of prostate cancer by increasing levels of a specific set of pro-inflammatory molecules compared with European-American men.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/21/6134/F1.large.jpg Cancer Res; 78(21); 6134-45. ©2018 AACR.

Cellular Constituents of the Prostate Stroma: Key Contributors to Prostate Cancer Progression and Therapy Resistance

Reciprocal signaling between prostate stroma and its epithelium are fundamental to organ development and homeostasis. Similarly, interactions between tumor cells and stromal constituents are central to key aspects of carcinogenesis and malignancy growth involving tumor cell invasion, dissemination, and growth in distant sites. The prostate stroma is complex with several distinct resident cell types, infiltrating nonresident cell types and an amalgam of structural matrix factors, matricellular proteins, metabolites, growth factors, and cytokines. Of importance, the stroma is dynamic with changes in composition as a cause or consequence of intrinsic and extrinsic factors. In the context of epithelial neoplasia, the prostate stroma undergoes phenotypic changes with a loss of well-differentiated smooth muscle cell population and the expansion of cancer-associated fibroblast populations. This reactive stroma further coevolves with tumor progression. Recent studies show the role of tumor microenvironment components in therapy resistance and highlight the importance of a thorough knowledge of cross talk between tumor cells and microenvironment niches to develop new therapeutic strategies.

Principles and approaches for reproducible scoring of tissue stains in research

Evaluation of tissues is a common and important aspect of translational research studies. Labeling techniques such as immunohistochemistry can stain cells/tissues to enhance identification of specific cell types, cellular activation states, and protein expression. While qualitative evaluation of labeled tissues has merit, use of semiquantitative and quantitative scoring approaches can greatly enhance the rigor of the tissue data. Adhering to key principles for reproducible scoring can enhance the quality and reproducibility of the tissue data so as to maximize its biological relevance and scientific impact.

Overcoming Oncogenic Mediated Tumor Immunity in Prostate Cancer

Immunotherapy is being tested intensively in clinical trials for prostate cancer; it includes immune checkpoint inhibition, prostate specific antigen (PSA) vaccines and dendritic cell-based strategies. Despite increasing evidence for clinical responses, the consensus of multiple trials is that prostate cancers are poorly responsive to immunotherapy. Prostate cancer has a high degree of pathological and genetic heterogeneity compared to other cancer types, which may account for immunotherapeutic resistance. This hypothesis also implies that select types of prostate tumors may be differentially responsive to immune-based strategies and that the clinical stage, pathological grade and underlying genetic landscape may be important criteria in identifying tumors that respond to immune therapies. One strategy is to target oncogenic driver pathways in combination with immunotherapies with the goal of overcoming tumor immunity and broadening the number of patients achieving a clinical response. In this analysis, we address the hypothesis that driver oncogenic signaling pathways regulate cancer progression, tumor immunity and resistance to current immune therapeutics in prostate cancer. We propose that increased responsiveness may be achieved through the combined use of immunotherapies and inhibitors targeting tumor cell autonomous pathways that contribute towards anti-tumor immunity in patients with prostate cancer.

Tenascin-C is a potential cancer-associated fibroblasts marker and predicts poor prognosis in prostate cancer

Tenascin-C (TNC), as a member of the extracellular matrix (ECM), plays an important role in cancer cell proliferation and migration and tumor invasion in various types of cancer. Here, we attempted to investigate the role of TNC as a prognostic factor in prostate cancer. We studied TNC expression via immunohistochemistry in 145 prostate cancer tissue samples. The clinicopathological relevance of TNC expression was examined, as well as other cancer-associated fibroblasts (CAFs)-related factors. Our results showed that the high levels of TNC expression in prostate cancer stroma was significantly associated with lymph node metastasis (P = 0.024) and clinical stage (P = 0.032). Furthermore, TNC was positively correlated with increased micro-vessel density (MVD) (P = 0.017) and tumor associated macrophage (TAM) population (P = 0.025). In both univariate and multivariate Cox regression analyses, TNC (P < 0.001) was an independent poor prognostic factor for overall survival in prostate cancer patients. Moreover, over-expression of TNC (P < 0.001), SMA (P = 0.042) and vimentin (P = 0.010) were significantly correlated with the lower overall survival. In addition, TNC expression in prostate cancer stroma was significantly associated with FSP1 (P = 0.011), SMA (P = 0.021), and vimentin (P = 0.002). In conclusion, our study revealed that high level of TNC as a potential biomarker of CAFs was significantly correlated with the poor prognosis for prostate cancer patients.

Synergistic immunologic targets for the treatment of prostate cancer

Prostate cancer is a common disease and, while detection and treatment have advanced, it remains a significant cause of morbidity and mortality in men. Research suggests significant involvement of the immune system in the pathogenesis and progression of prostate cancer, indicating that immunologic therapies may benefit patients. Two immunologic factors, interleukin-2 and transforming growth factor-β, may be especially attractive therapeutic targets for prostate cancer. Specifically, an increase in interleukin-2 signaling and a decrease in transforming growth factor-β signaling might help improve immunologic recognition and targeting of tumor cells. The purpose of this review is to highlight the evidence that interleukin-2 and blockade of transforming growth factor-β could be used to target prostate cancer based on current understanding of immune function in the context of prostate cancer. Additionally, current treatments related to these two factors for prostate and other cancers will be used to strengthen the argument for this strategy.