Bad seeds produce bad crops: a single stage-process of prostate tumor invasion

A bi-directional segmentation method for prostate ultrasound images under semantic constraints

Due to the lack of sufficient labeled data for the prostate and the extensive and complex semantic information in ultrasound images, accurately and quickly segmenting the prostate in transrectal ultrasound (TRUS) images remains a challenging task. In this context, this paper proposes a solution for TRUS image segmentation using an end-to-end bidirectional semantic constraint method, namely the BiSeC model. The experimental results show that compared with classic or popular deep learning methods, this method has better segmentation performance, with the Dice Similarity Coefficient (DSC) of 96.74% and the Intersection over Union (IoU) of 93.71%. Our model achieves a good balance between actual boundaries and noise areas, reducing costs while ensuring the accuracy and speed of segmentation.

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 Local Therapy for Oligometastatic Prostate Cancer: Should We Expect a Cure?

The role of local treatment in oligometastatic prostate cancer remains contentious. Treatment of the prostate in metastatic disease may confer benefit, but prospective data are lacking. With improvements in treatments, aggressive strategies directed at metastases have increasingly become of clinical interest. Current evidence suggests good local control can be achieved; however, further data are required to determine overall cancer outcomes. This article evaluates the evidence available and consider whether local treatment of oligometastatic disease is a feasible, safe, and a positive strategy in this disease cohort. Cure should not be expected, although prolonged disease and treatment-free survival may be observed.

Enhanced regulation of cell cycle and suppression of osteoblast differentiation molecular signatures by prostate cancer stem-like holoclones

AIMS

Targeting the stem cell properties of tumor-initiating cells is an avenue through which cancer treatment may be improved. Before this can be achieved, so-called 'cancer stem cell' (CSC) models must be developed and characterized in specific malignancies.

METHODS

In this study, holoclone formation assays were used to characterise stem-like molecular signatures in prostate cancer (PCa) cells.

RESULTS

LNCaP and PC3 parent cells were capable of responding to stem cell differentiation morphogen retinoic acid (RA), suggesting the presence of inherent stem-like properties. LNCaP cells, which represent early, androgen-responsive disease, formed holoclones after twenty six days. PC3 cells, which represent advanced, metastatic, castration-resistant disease, formed holoclones after only six days. Holoclones displayed decreased expression of RA-genes, suggesting a more immature, less differentiated phenotype. Gene and microRNA arrays demonstrated that holoclones downregulated a number of stem cell differentiation regulators while displaying enhanced regulation of G2 to M transition and the mitotic spindle checkpoint components of the cell cycle. PC3 holoclones displayed pronounced downregulation of known regulators of osteoblast differentiation from mesenchymal stem cells and Epithelial Mesenchymal Transition.

CONCLUSIONS

Our results suggest that some PCa cells retain the ability to transition to a more immature state in which differentiation and metastatic mechanisms are suppressed. The highlighting of osteoblast differentiation regulators in this mechanism is particularly notable, considering the propensity of PCa to metastasise to bone.

Advances in local and ablative treatment of oligometastasis in prostate cancer

Oligometastasis is a state of limited metastatic disease that may be amenable to aggressive local therapy to achieve long-term survival. This review aims to explore the role of ablative radiotherapy and surgical management of prostate cancer (CaP) patients with oligometastasis. We performed a systematic review of the literature from November 2003 to November 2013 in the PubMed and EMBASE databases using structured search terms. From our literature search, we identified 13 cases of oligometastatic CaP managed by surgery. The longest disease-free survival documented was 12 years following pulmonary metastasectomy. We also found 12 studies using radiotherapy to treat oligometastatic CaP with median follow-up ranging from 6 to 43 months. Local control rates and overall survival at 3 years range from 66 to 90% and from 54 to 92%, respectively. Most patients did not report any significant toxicity. The limited current literature suggests oligometastatic CaP may be amenable to more aggressive local ablative therapy to achieve prolonged local control and delay to androgen deprivation therapy (ADT). There is a larger body of evidence supporting the use of radiotherapy than surgery in this disease state. However, no direct comparison with ADT is available to suggest an improvement in overall survival. Further studies are required to determine the role of aggressive-targeted local therapy in oligometastatic CaP.

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.

Prostate cancer stem cell biology

The cancer stem cell (CSC) model provides insights into pathophysiology of cancers and their therapeutic response. The CSC model has been both controversial, yet provides a foundation to explore cancer biology. In this review, we provide an overview of CSC concepts, biology and potential therapeutic avenues. We then focus on prostate CSC including 1) their purported origin as either basal-derived or luminal-derived cells; 2) markers used for prostate CSC identification; 3) alterations of signaling pathways in prostate CSCs; 4) involvement of prostate CSCs in metastasis of PCa; and 5) microRNA-mediated regulation of prostate CSCs. Although definitive evidence for the identification and characterization of prostate CSCs still remains unclear, future directions pursuing therapeutic targets of CSCs may provide novel insights for the treatment of PCa.

Malignant transformation and stromal invasion from normal or hyperplastic tissues: true or false?

Carcinogenesis is believed to be a multi-step process, progressing sequentially from normal to hyperplastic, to in situ, and to invasive stages. A number of studies, however, have detected malignancy-associated alterations in normal or hyperplastic tissues. As the molecular profile and clinical features of these tissues have not been defined, the authors invited several well-recognized pathologist, oncologists, biologist, surgeons, and molecular biologist to offer their opinion on: (1) whether these tissues belong to a previously unrevealed malignant entity or focal alterations with no significant consequence? (2) whether these alterations are linked to early onset of cancer or cancer of unknown primary site, and (3) how to further define these lesions?

Prostate cancer stem cells and their potential roles in metastasis

Most solid tumors have now been reported to contain stem cell-like cells called cancer stem cells (CSCs). These cells are endowed with high tumorigenic capacity and may be the cells that drive tumor formation, maintain tumor homeostasis, and mediate tumor metastasis. Since these self-renewing cancer cells may be the sole population to develop a primary tumor, it is predicted that CSCs may also represent the lethal seeds of metastasis, as supported by a flurry of recent studies on the relationship between CSCs and metastasis. Herein, we summarize current knowledge of stem/progenitor cells and CSCs, especially in the context of normal human prostate and prostate cancer. We further update the recently gained knowledge on the involvement of CSCs in metastasis. We also discuss the fundamental influence of tumor microenvironment on the manifestation of CSCs and metastasis. Finally, we discuss the clinical implication of CSC-based therapy.

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.

Correlated alterations in prostate basal cell layer and basement membrane

Our recent studies revealed that focal basal cell layer disruption (FBCLD) induced auto-immunoreactions represented a contributing factor for human prostate tumor progression and invasion. As the basement membrane surrounds and attaches to the basal cell layer, our current study assessed whether FBCLD would impact the physical integrity of the associated basement membrane. Paraffin sections from 25-human prostate tumors were subjected to double immunohistochemistry to simultaneously elucidate the basal cell layer and the basement membrane with corresponding biomarkers. The physical integrity of the basement membrane overlying FBCLD was examined to determine the extent of correlated alterations. Of a total of 89 FBCLD encountered, 76 (85 %) showed correlated alterations in the overlying basement membrane, which included distinct focal disruptions or fragmentations. In the remaining 13 (15%) FBCLD, the overlying basement membrane showed significant attenuation or reduction of the immunostaining intensity. The basement membrane in all or nearly all ducts or acini with p63 positive basal cells was substantially thicker and more uniform than that in ducts or acini without p63 positive basal cells, and also, a vast majority of the focal disruptions occurred near basal cells that lack p63 expression. These findings suggest that focal disruptions in the basal cell layer and alterations in the basement membrane are correlated events and that the physical and functional status of the basal cells could significantly impact the physical integrity of the overlying basement membrane. As the degradation of both the basal cell layer and the basement membrane is a pre-requisite for prostate tumor invasion or progression, ducts or acini with focally disrupted basal cell layer and basement membrane are likely at greater risk to develop invasive lesions. Thus, further elucidation of the specific molecules and mechanism associated with these events may lead to the development of a more effective alternative for repeat biopsy to monitor tumor progression and invasion.

Aberrant c-erbB2 expression in cell clusters overlying focally disrupted breast myoepithelial cell layers: a trigger or sign for emergence of more aggressive cell clones?

Our recent studies revealed that cell clusters overlying focal myoepithelial cell layer disruption (FMCLD) had a significantly higher frequency of genetic instabilities and expression of invasion-related genes than their adjacent counterparts within the same duct. Our current study attempted to assess whether these cell clusters would also have elevated c-erbB2 expression. Human breast tumors (n=50) with a high frequency of FMCLD were analyzed with double immunohistochemistry, real-time RT-PCR, and chromogenic in situ hybridization for c-erbB2 protein and gene expression. Of 448 FMCLD detected, 404 (90.2%) were associated with cell clusters that had intense c-erbB2 immunoreactivities primarily in their cytoplasm, in contrast to their adjacent counterparts within the same duct, which had no or barely detectable c-erbB2 expression. These c-erbB2 positive cells were arranged as tongue-like projections, "puncturing" into the stroma, and about 20% of them were in direct continuity with tube-like structures that resembled blood vessels. Aberrant c-erbB2 expression was also seen in clusters of architecturally normal-appearing ducts that had distinct cytological abnormalities in both ME and epithelial cells, whereas not in their clear-cut normal counterparts. Molecular assays detected markedly higher c-erbB2 mRNA and gene amplification in cell clusters associated with FMCLD than in those associated with non-disrupted ME cell layers. Our findings suggest that cell clusters overlying FMCLD may represent the precursors of pending invasive lesions, and that aberrant c-erbB2 expression may trigger or signify the emergence of biologically more aggressive cell clones.

Bad seeds produce bad crops: a single stage-process of prostate tumor invasion

It is a commonly held belief that prostate carcinogenesis is a multi-stage process and that tumor invasion is triggered by the overproduction of proteolytic enzymes. This belief is consistent with data from cell cultures and animal models, whereas is hard to interpret several critical facts, including the presence of cancer in "healthy" young men and cancer DNA phenotype in morphologically normal prostate tissues. These facts argue that alternative pathways may exist for prostate tumor invasion in some cases. Since degradation of the basal cell layer is the most distinct sign of invasion, our recent studies have attempted to identify pre-invasive lesions with focal basal cell layer alterations. Our studies revealed that about 30% of prostate cancer patients harbored normal appearing duct or acinar clusters with a high frequency of focal basal cell layer disruptions. These focally disrupted basal cell layers had significantly reduced cell proliferation and tumor suppressor expression, whereas significantly elevated degeneration, apoptosis, and infiltration of immunoreactive cells. In sharp contrast, associated epithelial cell had significantly elevated proliferation, expression of malignancy-signature markers, and physical continuity with invasive lesions. Based on these and other findings, we have proposed that these normal appearing duct or acinar clusters are derived from monoclonal proliferation of genetically damaged stem cells and could progress directly to invasion through two pathways: 1) clonal in situ transformation (CIST) and 2) multi-potential progenitor mediated "budding" (MPMB). These pathways may contribute to early onset of prostate cancer at young ages, and to clinically more aggressive prostate tumors.