The role of adhesion molecules as biomarkers for the aggressive prostate cancer phenotype

The Prospect of Identifying Resistance Mechanisms for Castrate-Resistant Prostate Cancer Using Circulating Tumor Cells: Is Epithelial-to-Mesenchymal Transition a Key Player?

Prostate cancer (PCa) is initially driven by excessive androgen receptor (AR) signaling with androgen deprivation therapy (ADT) being a major therapeutic approach to its treatment. However, the development of drug resistance is a significant limitation on the effectiveness of both first-line and more recently developed second-line ADTs. There is a need then to study AR signaling within the context of other oncogenic signaling pathways that likely mediate this resistance. This review focuses on interactions between AR signaling, the well-known phosphatidylinositol-3-kinase/AKT pathway, and an emerging mediator of these pathways, the Hippo/YAP1 axis in metastatic castrate-resistant PCa, and their involvement in the regulation of epithelial-mesenchymal transition (EMT), a feature of disease progression and ADT resistance. Analysis of these pathways in circulating tumor cells (CTCs) may provide an opportunity to evaluate their utility as biomarkers and address their importance in the development of resistance to current ADT with potential to guide future therapies.

Effects of claudin-1 downregulation on the physiological processes of gallbladder cancer SGC996 cells

Gallbladder cancer has a high recurrence and mortality rate, with limited treatment options. Therefore, elucidating the underlying molecular mechanisms of this disease would be beneficial to achieve an earlier diagnosis and potentially identify novel treatment targets. Claudin-1 is a tight junction protein associated with the development and prognosis of several types of cancer, and our preliminary studies have demonstrated that claudin-1 expression is elevated in gallbladder cancer tissues. Therefore, the aim of the present study was to investigate the effects of downregulating claudin-1 on the physiological processes of gallbladder cancer cells. The gallbladder cancer SGC996 cell line was transfected with claudin-1-RNA interference lentivirus (LV-CLDN1-RNAi) to downregulate claudin-1 expression, and the downstream effects on cell proliferation, the cell cycle, apoptosis and cell invasion were investigated. Following transfection with LV-CLDN1-RNAi, the results of an MTT assay revealed that downregulating claudin-1 did not affect the proliferation of the SGC996 cells. However, flow cytometry analysis demonstrated that the number of cells arrested in the G₁ phase increased significantly, whereas the amount of cells arrested in the S phase was significantly reduced. Annexin V-APC single-color staining demonstrated that downregulating claudin-1 expression increased the ratio of cell apoptosis, which was confirmed by the results of western blot analysis, in which levels of the pro-apoptotic B-cell lymphoma 2 (Bcl-2)-associated X protein and anti-apoptotic Bcl-2 protein were increased and decreased, respectively. Finally, a Transwell assay indicated that claudin-1 downregulation inhibited cell invasion. Overall, the results from the present study indicated that downregulating claudin-1 expression promoted the apoptosis of gallbladder cancer cells and inhibited cell invasion, indicating that claudin-1 may be involved in the recurrence and metastasis of gallbladder cancer. These insights provide theoretical and experimental foundations for considering claudin-1 as a novel target for the treatment of gallbladder cancer.

Live-single-cell phenotypic cancer biomarkers-future role in precision oncology?

The promise of precision and personalized medicine is rooted in accurate, highly sensitive, and specific disease biomarkers. This is particularly true for cancer-a disease characterized by marked tumor heterogeneity and diverse molecular signatures. Although thousands of biomarkers have been described, only a very small number have been successfully translated into clinical use. Undoubtedly, there is need for rapid, quantitative, and more cost effective biomarkers for tumor diagnosis and prognosis, to allow for better risk stratification and aid clinicians in making personalized treatment decisions. This is particularly true for cancers where specific biomarkers are either not available (e.g., renal cell carcinoma) or where current biomarkers tend to classify individuals into broad risk categories unable to accurately assess individual tumor aggressiveness and adverse pathology potential (e.g., prostate cancer), thereby leading to problems of over-diagnosis and over-treatment of indolent cancer and under-treatment of aggressive cancer. This perspective highlights an emerging class of cancer biomarkers-live-single-cell phenotypic biomarkers, as compared to genomic biomarkers, and their potential application for cancer diagnosis, risk-stratification, and prognosis.

Genome-wide copy number analysis reveals candidate gene loci that confer susceptibility to high-grade prostate cancer

BACKGROUND

Two key issues in prostate cancer (PCa) that demand attention currently are the need for a more precise and minimally invasive screening test owing to the inaccuracy of prostate-specific antigen and differential diagnosis to distinguish advanced vs. indolent cancers. This continues to pose a tremendous challenge in diagnosis and prognosis of PCa and could potentially lead to overdiagnosis and overtreatment complications. Copy number variations (CNVs) in the human genome have been linked to various carcinomas including PCa. Detection of these variants may improve clinical treatment as well as an understanding of the pathobiology underlying this complex disease.

METHODS

To this end, we undertook a pilot genome-wide CNV analysis approach in 36 subjects (18 patients with high-grade PCa and 18 controls that were matched by age and ethnicity) in search of more accurate biomarkers that could potentially explain susceptibility toward high-grade PCa. We conducted this study using the array comparative genomic hybridization technique. Array results were validated in 92 independent samples (46 high-grade PCa, 23 benign prostatic hyperplasia, and 23 healthy controls) using polymerase chain reaction-based copy number counting method.

RESULTS

A total of 314 CNV regions were found to be unique to PCa subjects in this cohort (P<0.05). A log₂ ratio-based copy number analysis revealed 5 putative rare or novel CNV loci or both associated with susceptibility to PCa. The CNV gain regions were 1q21.3, 15q15, 7p12.1, and a novel CNV in PCa 12q23.1, harboring ARNT, THBS1, SLC5A8, and DDC genes that are crucial in the p53 and cancer pathways. A CNV loss and deletion event was observed at 8p11.21, which contains the SFRP1 gene from the Wnt signaling pathway. Cross-comparison analysis with genes associated to PCa revealed significant CNVs involved in biological processes that elicit cancer pathogenesis via cytokine production and endothelial cell proliferation.

CONCLUSION

In conclusion, we postulated that the CNVs identified in this study could provide an insight into the development of advanced PCa.

PRL-3 promotes cell adhesion by interacting with JAM2 in colon cancer

Phosphatase of regenerating liver-3 (PRL-3), also termed PTP4A3, is a metastasis-related protein tyrosine phosphatase. Its expression levels are significantly correlated with the progression and survival of a wide range of malignant tumors. However, the mechanism by which PRL-3 promotes tumor invasion and metastasis is not clear. In the present study, the functions of PRL-3 were systemically analyzed in the key events of metastasis including, motility and adhesion. A cell wounding assay, cell spread assay and cell-matrix adhesion assay were carried out to analyze the cell movement and cell adhesion ability of colon cancer, immunoprecipitation and immunofluorescence assay was confirmed the interaction of PRL-3 and JAM2. It was demonstrated that PRL-3 promoted the motility of Flp-In-293 and LoVo colon cancer cells and increased the distribution of cell skeleton proteins on the cell protrusions. In addition, stably expressing PRL-3 reduced the spreading speed of colon cancer cells and cell adhesion on uncoated, fibronectin-coated and collagen I-coated plates. Mechanistically, junction adhesion molecular 2 (JAM2) was identified as a novel interacting protein of PRL-3. The findings of the present study revealed the roles of PRL-3 in cancer cell motility and adhesion process, and provided information on the possibility of PRL-3 increase cell-cell adhesion by associating with JAM2.