Correlated alterations in prostate basal cell layer and basement membrane

Deposition of collagen III and alterations in basement membrane integrity as candidate prognostic markers in prostate cancer

The extracellular matrix surrounding the tumor undergoes changes in its organization during the metastasis process. The present study aims to quantify total collagen, collagen I (Col I) and collagen III (Col III), analyze the alignment of collagen fibers and assess the basement membrane integrity in samples from patients with metastatic and non-metastatic prostate cancer. Tissue samples from 60 patients were classified into groups based on prognostic parameters: better prognosis (n = 20), worse prognosis without metastasis (n = 23) and metastatic (n = 17). Picrosirius red with further analysis under polarizing microscope was used to quantify (with validation using immunohistochemistry) and analyze collagen alignment, and Periodic Acid Schiff staining was used to analyze the basement membrane integrity. The Col I/Col III ratio was found to be higher in the metastatic group than in the groups with better prognosis (p = 0.012) and worse prognosis without metastasis (p = 0.018). Basement membrane integrity constitution in malignant tumor tissue differed from that of adjacent non-tumor tissue (p < 0.001). Moreover, the worsening in the tumor tissue integrity was positively correlated with worse prognostic parameters. All in all, absence of Col III and basement membrane integrity might be indicators of poor prognosis in prostate cancer.

Identification of a basement membrane-related genes signature with immune correlation in bladder urothelial carcinoma and verification in vitro

BACKGROUND

Bladder urothelial carcinoma (BLCA) is the most common genitourinary cancer and the prognosis of patients is often poor. However, studies of basement membrane-related genes (BM-related genes) in BLCA are less reported. Therefore, we established a BM-related genes signature to explore their functional and prognostic value in BLCA.

METHODS

In this study, a BM-related genes signature was constructed by LASSO-Cox regression analysis, and then a series of bioinformatics methods was used to assess the accuracy and validity of the signature. We constructed a nomogram for clinical application and also screened for possible therapeutic drugs. To investigate the functions and pathways affected by BM-related genes in BLCA, we performed functional enrichment analyses. In addition, we analyzed the immune cell infiltration landscape and immune checkpoint-related genes in the high and low-risk groups. Finally, we confirmed the prognostic value of BM-related genes in BLCA in vitro.

RESULTS

Combining multiple bioinformatics approaches, we identified a seven-gene signature. The accuracy and validity of this signature in predicting BLCA patients were confirmed by the test cohort. In addition, the risk score was strongly correlated with prognosis, immune checkpoint genes, drug sensitivity, and immune cell infiltration landscape. The risk score is an independent prognostic factor for BLCA patients. Further experiments revealed that all seven signature genes were differentially expressed between BLCA cell lines and normal bladder cells. Finally, overexpression of LAMA2 inhibited the migration and invasion ability of BLCA cell lines.

CONCLUSIONS

In summary, the BM-related genes signature was able to predict the prognosis of BLCA patients accurately, indicating that the BM-related genes possess great clinical value in the diagnosis and treatment of BLCA. Moreover, LAMA2 could be a potential therapeutic target, which provides new insights into the application of the BM-related genes in BLCA patients.

Exploring the Onset and Progression of Prostate Cancer through a Multicellular Agent-based Model

Over 10% of men will be diagnosed with prostate cancer during their lifetime. Arising from luminal cells of the prostatic acinus, prostate cancer is influenced by multiple cells in its microenvironment. To expand our knowledge and explore means to prevent and treat the disease, it is important to understand what drives the onset and early stages of prostate cancer. In this study, we developed an agent-based model of a prostatic acinus including its microenvironment, to allow for in silico studying of prostate cancer development. The model was based on prior reports and in-house data of tumor cells cocultured with cancer-associated fibroblasts (CAF) and protumor and/or antitumor macrophages. Growth patterns depicted by the model were pathologically validated on hematoxylin and eosin slide images of human prostate cancer specimens. We identified that stochasticity of interactions between macrophages and tumor cells at early stages strongly affect tumor development. In addition, we discovered that more systematic deviations in tumor development result from a combinatorial effect of the probability of acquiring mutations and the tumor-promoting abilities of CAFs and macrophages. In silico modeled tumors were then compared with 494 patients with cancer with matching characteristics, showing strong association between predicted tumor load and patients' clinical outcome. Our findings suggest that the likelihood of tumor formation depends on a combination of stochastic events and systematic characteristics. While stochasticity cannot be controlled, information on systematic effects may aid the development of prevention strategies tailored to the molecular characteristics of an individual patient.

Significance

We developed a computational model to study which factors of the tumor microenvironment drive prostate cancer development, with potential to aid the development of new prevention strategies.

The most effective but largely ignored target for prostate cancer early detection and intervention

Over the past two decades, the global efforts for the early detection and intervention of prostate cancer seem to have made significant progresses in the basic researches, but the clinic outcomes have been disappointing: (1) prostate cancer is still the most common non-cutaneous cancer in Europe in men, (2) the age-standardized prostate cancer rate has increased in nearly all Asian and African countries, (3) the proportion of advanced cancers at the diagnosis has increased to 8.2% from 3.9% in the USA, (4) the worldwide use of PSA testing and digital rectal examination have failed to reduce the prostate cancer mortality, and (5) there is still no effective preventive method to significantly reduce the development, invasion, and metastasis of prostate cancer… Together, these facts strongly suggest that the global efforts during the past appear to be not in a correlated target with markedly inconsistent basic research and clinic outcomes. The most likely cause for the inconsistence appears due to the fact that basic scientific studies are traditionally conducted on the cell lines and animal models, where it is impossible to completely reflect or replicate the in vivo status. Thus, we would like to propose the human prostate basal cell layer (PBCL) as “the most effective target for the early detection and intervention of prostate cancer”. Our proposal is based on the morphologic, immunohistochemical and molecular evidence from our recent studies of normal and cancerous human prostate tissues with detailed clinic follow-up data. We believe that the human tissue-derived basic research data may provide a more realistic roadmap to guide the clinic practice and to avoid the potential misleading from in vitro and animal studies.

The Role of Cancer-Associated Fibroblasts in Prostate Cancer Tumorigenesis

Tumors strongly depend on their surrounding tumor microenvironment (TME) for growth and progression, since stromal elements are required to generate the optimal conditions for cancer cell proliferation, invasion, and possibly metastasis. Prostate cancer (PCa), though easily curable during primary stages, represents a clinical challenge in advanced stages because of the acquisition of resistance to anti-cancer treatments, especially androgen-deprivation therapies (ADT), which possibly lead to uncurable metastases such as those affecting the bone. An increasing number of studies is giving evidence that prostate TME components, especially cancer-associated fibroblasts (CAFs), which are the most abundant cell type, play a causal role in PCa since the very early disease stages, influencing therapy resistance and metastatic progression. This is highlighted by the prognostic value of the analysis of stromal markers, which may predict disease recurrence and metastasis. However, further investigations on the molecular mechanisms of tumor-stroma interactions are still needed to develop novel therapeutic approaches targeting stromal components. In this review, we report the current knowledge of the characteristics and functions of the stroma in prostate tumorigenesis, including relevant discussion of normal prostate homeostasis, chronic inflammatory conditions, pre-neoplastic lesions, and primary and metastatic tumors. Specifically, we focus on the role of CAFs, to point out their prognostic and therapeutic potential in PCa.

Castration-induced stromal remodeling disrupts the reconstituted prostate epithelial structure

The normal prostate epithelial structure is maintained by homeostatic interactions with smooth muscle cells. However, structural alterations of the stroma are commonly observed in prostatic proliferative diseases, leading to the abnormalities of prostate epithelial structure. A decrease in the androgen level experimentally induces stromal remodeling, i.e., replacement of smooth muscle cells with fibroblasts or myofibroblasts. In this study, we investigated the effects of castration-induced stromal remodeling and subsequent aberrant activation of epithelial-stromal interactions on the reconstituted human prostate-like epithelial structure. We performed in vivo experiments using the human prostate epithelial cell line BPH-1 and fetal rat urogenital sinus mesenchyme to generate heterotypic tissue recombinants that form human prostate-like epithelial structure (i.e., solid- and canalized-epithelial cords). Host mice were castrated at 12 weeks post transplantation (castration) and implanted with a dihydrotestosterone pellet at 14 days post castration (androgen replacement treatment; ART). In the castration group, the percentages of fibrotic area and disrupted prostate epithelial structure without the basement membrane (BM) increased proportionally in a time-dependent manner, but were suppressed by ART. In the castration group, tenascin-C (TNC)-positive fibroblasts were abundant in the stroma surrounding disrupted prostate epithelial structure without the BM. TGF-β1 secretion from BPH-1 cells was increased by co-culturing with human primary cultured prostate fibroblasts. TNC mRNA expression was increased in fibroblasts co-culturing with BPH-1 cells and was suppressed by treatment with a TGF-β RI kinase inhibitor. Moreover, in the castration group, the percentage of p-Smad2-positive cells was significantly higher in the stroma surrounding disrupted prostate epithelial structure without the BM. Our results demonstrate that castration-induced stromal remodeling disrupted the reconstituted human prostate-like epithelial structure and induced the appearance of TNC-positive fibroblasts accompanied by activation of TGF-β signaling. The alteration of prostate stromal structure may be responsible for loss of the BM and epithelial cell polarity.

Beyond proteases: Basement membrane mechanics and cancer invasion

In epithelial cancers, cells must invade through basement membranes (BMs) to metastasize. The BM, a thin layer of extracellular matrix underlying epithelial and endothelial tissues, is primarily composed of laminin and collagen IV and serves as a structural barrier to cancer cell invasion, intravasation, and extravasation. BM invasion has been thought to require protease degradation since cells, which are typically on the order of 10 µm in size, are too large to squeeze through the nanometer-scale pores of the BM. However, recent studies point toward a more complex picture, with physical forces generated by cancer cells facilitating protease-independent BM invasion. Moreover, collective cell interactions, proliferation, cancer-associated fibroblasts, myoepithelial cells, and immune cells are all implicated in regulating BM invasion through physical forces. A comprehensive understanding of BM structure and mechanics and diverse modes of BM invasion may yield new strategies for blocking cancer progression and metastasis.

High-throughput quantum cascade laser (QCL) spectral histopathology: a practical approach towards clinical translation

Infrared microscopy has become one of the key techniques in the biomedical research field for interrogating tissue. In partnership with multivariate analysis and machine learning techniques, it has become widely accepted as a method that can distinguish between normal and cancerous tissue with both high sensitivity and high specificity. While spectral histopathology (SHP) is highly promising for improved clinical diagnosis, several practical barriers currently exist, which need to be addressed before successful implementation in the clinic. Sample throughput and speed of acquisition are key barriers and have been driven by the high volume of samples awaiting histopathological examination. FTIR chemical imaging utilising FPA technology is currently state-of-the-art for infrared chemical imaging, and recent advances in its technology have dramatically reduced acquisition times. Despite this, infrared microscopy measurements on a tissue microarray (TMA), often encompassing several million spectra, takes several hours to acquire. The problem lies with the vast quantities of data that FTIR collects; each pixel in a chemical image is derived from a full infrared spectrum, itself composed of thousands of individual data points. Furthermore, data management is quickly becoming a barrier to clinical translation and poses the question of how to store these incessantly growing data sets. Recently, doubts have been raised as to whether the full spectral range is actually required for accurate disease diagnosis using SHP. These studies suggest that once spectral biomarkers have been predetermined it may be possible to diagnose disease based on a limited number of discrete spectral features. In this current study, we explore the possibility of utilising discrete frequency chemical imaging for acquiring high-throughput, high-resolution chemical images. Utilising a quantum cascade laser imaging microscope with discrete frequency collection at key diagnostic wavelengths, we demonstrate that we can diagnose prostate cancer with high sensitivity and specificity. Finally we extend the study to a large patient dataset utilising tissue microarrays, and show that high sensitivity and specificity can be achieved using high-throughput, rapid data collection, thereby paving the way for practical implementation in the clinic.

A new proposed rodent model of chemically induced prostate carcinogenesis: distinct time-course prostate cancer progression in the dorsolateral and ventral lobes

BACKGROUND

Characterization of novel rodent models for prostate cancer studies requires evaluation of either spontaneous and carcinogen-induced tumors as well as tumor incidence in different prostatic lobes. We propose a new short-term rodent model of chemically induced prostate carcinogenesis in which prostate cancer progression occurs differentially in the dorsolateral and ventral lobes.

METHODS

Adult gerbils were treated with MNU alone or associated with testosterone for 3 or 6 months of treatment. Tumor incidence, latency, localization, and immunohistochemistry (AR, PCNA, smooth muscle α-actin, p63, MGMT, and E-cadherin) were studied in both lobes.

RESULTS

Comparisons between both lobes revealed that lesions developed first in the DL while the VL presented longer tumor latency. However, after 6 months, there was a dramatic increase in tumor multiplicity in the VL, mainly in MNU-treated groups. Lesions clearly progressed from a premalignant to a malignant phenotype over time and tumor latency was decreased by MNU + testosterone administration. Three-dimensional reconstruction of the prostatic complex showed that the DL developed tumors exclusively in the periurethral area and showed intense AR, PCNA, and MGMT immunostaining. Moreover, VL lesions emerged throughout the entire lobe. MNU-induced lesions presented markers indicative of an aggressive phenotype: lack of basal cells, rupture of the smooth muscle cell layer, loss of E-cadherin, and high MGMT staining.

CONCLUSIONS

There are distinct pathways involved in tumor progression in gerbil prostate lobes. This animal provides a good model for prostate cancer since it allows the investigation of advanced steps of carcinogenesis with shorter latency periods in both lobes.

Tumor-infiltrating immune cells promoting tumor invasion and metastasis: existing theories

It is a commonly held belief that infiltration of immune cells into tumor tissues and direct physical contact between tumor cells and infiltrated immune cells is associated with physical destructions of the tumor cells, reduction of the tumor burden, and improved clinical prognosis. An increasing number of studies, however, have suggested that aberrant infiltration of immune cells into tumor or normal tissues may promote tumor progression, invasion, and metastasis. Neither the primary reason for these contradictory observations, nor the mechanism for the reported diverse impact of tumor-infiltrating immune cells has been elucidated, making it difficult to judge the clinical implications of infiltration of immune cells within tumor tissues. This mini-review presents several existing hypotheses and models that favor the promoting impact of tumor-infiltrating immune cells on tumor invasion and metastasis, and also analyzes their strength and weakness.

The role of proteomics in prostate cancer research: biomarker discovery and validation

PURPOSE

Prostate Cancer (PCa) represents the second most frequent type of tumor in men worldwide. Incidence increases with patient age and represents the most important risk factor. PCa is mostly characterized by indolence, however in a small percentage of cases (3%) the disease progresses to a metastatic state. To date, the most important issue concerning PCa research is the difficulty in distinguishing indolent from aggressive disease. This problem frequently results in low-grade PCa patient overtreatment and, in parallel; an effective treatment for distant and aggressive disease is not yet available.

RESULT

Proteomics represents a promising approach for the discovery of new biomarkers able to improve the management of PCa patients. Markers more specific and sensitive than PSA are needed for PCa diagnosis, prognosis and response to treatment. Moreover, proteomics could represent an important tool to identify new molecular targets for PCa tailored therapy. Several possible PCa biomarkers sources, each with advantages and limitations, are under investigation, including tissues, urine, serum, plasma and prostatic fluids. Innovative high-throughput proteomic platforms are now identifying and quantifying new specific and sensitive biomarkers for PCa detection, stratification and treatment. Nevertheless, many putative biomarkers are still far from being applied in clinical practice.

CONCLUSIONS

This review aims to discuss the recent advances in PCa proteomics, emphasizing biomarker discovery and their application to clinical utility for diagnosis and patient stratification.

DC-SCRIPT: AR and VDR regulator lost upon transformation of prostate epithelial cells

BACKGROUND

Nuclear receptors (NR), including the Androgen Receptor (AR) and the Vitamin D Receptor (VDR), play an important role in prostate cancer etiology. We recently found that DC-SCRIPT is a prognostic marker in breast cancer and a unique NR coregulator differentially regulating different classes of NRs. Here we investigated the importance of DC-SCRIPT in prostate cancer.

METHODS

DC-SCRIPT mRNA expression was measured by qPCR. Immunohistochemistry was used to detect DC-SCRIPT protein expression. The functional effects of DC-SCRIPT on the transcriptional activity of AR and VDR were assessed by luciferase reporter assays and qPCR assays on well-known AR and VDR target genes.

RESULTS

DC-SCRIPT mRNA was higher in normal than in corresponding malignant prostate tissue but could not be related to disease stage. DC-SCRIPT protein was found in morphologically normal prostate glands and in infiltrating immune cells. Strikingly, DC-SCRIPT protein expression was absent in malignant prostate epithelial tissue and prostate carcinoma cell lines. DC-SCRIPT protein expression appears to be lost prior to the basal cell marker HMW cytokeratin used in prostate carcinoma diagnostics. In addition, our data demonstrated that DC-SCRIPT repressed transcription mediated by wild-type and mutated AR while enhancing VDR mediated transcription. In addition, transient expression of DC-SCRIPT expression in prostate carcinoma cells strongly repressed cell growth.

CONCLUSIONS

DC-SCRIPT is a key regulator of nuclear receptors AR and VDR that play an opposite role in prostate cancer etiology and loss of DC-SCRIPT may be involved in the onset of prostate cancer.

miR-205 regulates basement membrane deposition in human prostate: implications for cancer development

The basement membrane (BM) is a layer of specialized extracellular matrix that surrounds normal prostate glands and preserves tissue integrity. Lack or discontinuity of the BM is a prerequisite for tumor cell invasion into interstitial spaces, thus favoring metastasis. Therefore, BM maintenance represents a barrier against cancer development and progression. In the study, we show that miR-205 participates in a network involving ΔNp63α, which is essential for maintenance of the BM in prostate epithelium. At the molecular level, ΔNp63α is able to enhance miR-205 transcription by binding to its promoter, whereas the microRNA can post-transcriptionally limit the amount of ΔNp63α protein, mostly by affecting ΔNp63α proteasomal degradation rather than through a canonical miRNA/target interaction. Functionally, miR-205 is able to control the deposition of laminin-332 and its receptor integrin-β4. Hence, pathological loss of miR-205, as widely observed in prostate cancer, may favor tumorigenesis by creating discontinuities in the BM. Here we demonstrate that therapeutic replacement of miR-205 in prostate cancer (PCa) cells can restore BM deposition and 3D organization into normal-like acinar structures, thus hampering cancer progression.

The myoepithelial cell layer may serve as a potential trigger factor for different outcomes of stage-matched invasive lobular and ductal breast cancers

Invasive lobular cancer (ILC) tends to be significantly larger in size with significantly more positive lymph nodes, whereas ILC has a significantly more favorable outcome, compared to stage-matched invasive ductal carcinoma (IDC). The mechanism accounting for such differences remains elusive. Based on morphological, immunohistochemical, and molecular studies of over 1,000 cases of human breast cancers, we hypothesize that the differences may result from the structural and/or functional differences of their surrounding myoepithelial cell layers, which dictate lobular and ductal tumor cells to follow different pathways of invasion or metastasis. The background, rationale, supportive data, and implications of our hypothesis are presented and discussed.

A seemingly most effective target for early detection and intervention of prostate tumor invasion

This commentary proposes that budding tumor cell projections from focally disrupted tumor capsules represent a most effective target for early detection and intervention of prostate tumor invasion. The rationale, supporting data, and clinical applications of the hypothesis are discussed.

Protein profiling of isolated leukocytes, myofibroblasts, epithelial, Basal, and endothelial cells from normal, hyperplastic, cancerous, and inflammatory human prostate tissues

In situ neoplastic prostate cells are not lethal unless they become invasive and metastatic. For cells to become invasive, the prostate gland must undergo degradation of the basement membrane and disruption of the basal cell layer underneath the luminal epithelia. Although the roles of proteinases in breaking down the basement membrane have been well-studied, little is known about the factors that induce basal cell layer disruption, degeneration, and its eventual disappearance in invasive cancer. It is hypothesized that microenvironmental factors may affect the degradation of the basal cell layer, which if protected may prevent tumor progression and invasion. In this study, we have revealed differential protein expression patterns between epithelial and stromal cells isolated from different prostate pathologies and identified several important epithelial and stromal proteins that may contribute to inflammation and malignant transformation of human benign prostate tissues to cancerous tissues using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and proteomics methods. Cellular retinoic acid-binding protein 2 was downregulated in basal cells of benign prostate. Caspase-1 and interleukin-18 receptor 1 were highly expressed in leukocytes of prostate cancer. Proto-oncogene Wnt-3 was downregulated in endothelial cells of prostatitis tissue and tyrosine phosphatase non receptor type 1 was only found in normal and benign endothelial cells. Poly ADP-ribose polymerase 14 was downregulated in myofibroblasts of prostatitis tissue. Interestingly, integrin alpha-6 was upregulated in epithelial cells but not detected in myofibroblasts of prostate cancer. Further validation of these proteins may generate new strategies for the prevention of basal cell layer disruption and subsequent cancer invasion.

p63 in skin development and ectodermal dysplasias

The transcription factor p63 is critically important for skin development and maintenance. Processes that require p63 include epidermal lineage commitment, epidermal differentiation, cell adhesion, and basement membrane formation. Not surprisingly, alterations in the p63 pathway underlie a subset of ectodermal dysplasias, developmental syndromes in which the skin and skin appendages do not develop normally. This review summarizes the current understanding of the role of p63 in normal development and ectodermal dysplasias.