Predictive value of serum bone sialoprotein and prostate-specific antigen doubling time in patients with bone metastasis of prostate cancer

The Potential of Extracellular Matrix- and Integrin Adhesion Complex-Related Molecules for Prostate Cancer Biomarker Discovery

Prostate cancer is among the top five cancer types according to incidence and mortality. One of the main obstacles in prostate cancer management is the inability to foresee its course, which ranges from slow growth throughout years that requires minimum or no intervention to highly aggressive disease that spreads quickly and resists treatment. Therefore, it is not surprising that numerous studies have attempted to find biomarkers of prostate cancer occurrence, risk stratification, therapy response, and patient outcome. However, only a few prostate cancer biomarkers are used in clinics, which shows how difficult it is to find a novel biomarker. Cell adhesion to the extracellular matrix (ECM) through integrins is among the essential processes that govern its fate. Upon activation and ligation, integrins form multi-protein intracellular structures called integrin adhesion complexes (IACs). In this review article, the focus is put on the biomarker potential of the ECM- and IAC-related molecules stemming from both body fluids and prostate cancer tissue. The processes that they are involved in, such as tumor stiffening, bone turnover, and communication via exosomes, and their biomarker potential are also reviewed.

Biomarkers for Prostate Cancer Bone Metastasis Detection and Prediction

Prostate cancer (PCa) causes deaths worldwide, ranking second after lung cancer. Bone metastasis (BM) frequently results from advanced PCa, affecting approximately 90% of patients, and it also often results in severe skeletal-related events. Traditional diagnostic methods for bone metastases, such as tissue biopsies and imaging, have substantial drawbacks. This article summarizes the significance of biomarkers in PCa accompanied with BM, including (1) bone formation markers like osteopontin (OPN), pro-collagen type I C-terminal pro-peptide (PICP), osteoprotegerin (OPG), pro-collagen type I N-terminal pro-peptide (PINP), alkaline phosphatase (ALP), and osteocalcin (OC); (2) bone resorption markers, including C-telopeptide of type I collagen (CTx), N-telopeptide of type I collagen (NTx), bone sialoprotein (BSP), tartrate-resistant acid phosphatase (TRACP), deoxypyridinoline (D-PYD), pyridoxine (PYD), and C-terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP); (3) prostate-specific antigen (PSA); (4) neuroendocrine markers, such as chromogranin A (CgA), neuron-specific enolase (NSE), and pro-gastrin releasing peptide (ProGRP); (5) liquid biopsy markers, such as circulating tumor cells (CTCs), microRNA (miRNA), circulating tumor DNA (ctDNA), and cell-free DNA (cfDNA) and exosomes. In summary, some of these markers are already in widespread clinical use, while others still require further laboratory or clinical studies to validate their value for clinical application.

An Update on the Prognostic and Predictive Serum Biomarkers in Metastatic Prostate Cancer

Serum biomarkers are molecules produced by normal and abnormal cells. Prostate specific antigen (PSA) is an example of a serum biomarker used widely in the diagnosis and prognostication of prostate cancer. PSA has its limitations as it is organ- but not cancer-specific. The aim of this review is to summarize the current published data on the potential prognostic and predictive biomarkers in metastatic prostate cancer (mPC) that can be used in conjunction with PSA. These biomarkers include microRNAs, androgen receptor variants, bone metabolism, neuroendocrine and metabolite biomarkers, and could guide treatment selection and sequence in an era where we strive to personalized therapy.

SB225002 inhibits prostate cancer invasion and attenuates the expression of BSP, OPN and MMP‑2

The mechanisms of malignant cell metastasis to secondary sites are complex and multifactorial. Studies have demonstrated that small integrin-binding ligand N-linked glycoproteins (SIBLINGs), particularly bone sialoprotein (BSP) and osteopontin (OPN), are involved in neoplastic growth and metastasis. SIBLINGs promote malignant cell invasion and metastasis by enhancing matrix metalloproteinase 2 (MMP-2) and MMP-9 expression. Moreover, BSP and OPN can combine with integrin, which is located on the tumor cell surface, to further promote the malignant behavior of tumor cells. In the present study, we investigated whether SB225002, a specific CXCR2 receptor antagonist, can inhibit prostate cancer cell expression of BSP and OPN and reduce cancer cell invasion ability. A series of experiments showed that after SB225002 treatment, the proliferation, invasion and migration of two androgen-independent prostate cancer cell lines were inhibited, but this inhibitory effect was not observed on androgen-dependent prostate cancer cells. Western blotting showed that the PI3K signaling pathway could regulate the expression of SIBLING and MMP family proteins, and SB22055 could reduce the expression of BSP, OPN and MMP-2 in prostate cancer cells by inhibiting AKT/mTOR phosphorylation. Finally, in vivo experiments confirmed that SB225002 inhibited the proliferation of prostate cancer cells in vivo, and the expression levels of BSP, OPN and MMP-2 were also inhibited.

Influence of age on seven putative prostate tumor markers: a cohort study in Chinese men

The accuracy and sensitivity of prostate-specific antigen (PSA) for prostate cancer diagnosis is often poor; however, the reasons for its inaccuracy have rarely been investigated, especially with respect to age. In this study, 476 healthy males, aged 10-89 years, were stratified into eight age groups, and levels of seven markers were determined: total PSA (tPSA), free PSA (fPSA), %fPSA, isoform [-2]proPSA (p2PSA), p2PSA/tPSA, %p2PSA, and the prostate health index (PHI). Both tPSA and fPSA levels increased with age. The tPSA level was highest (1.39 ng ml-1) at 70-79 years; %fPSA was highest (0.57 ng ml-1) at 10-19 years; and %p2PSA was lowest (18.33 ng ml-1) at 40-49 years. Both p2PSA and p2PSA/tPSA had relatively flat curves and showed no correlation with age (P = 0.222). PHI was a sensitive age-associated marker (P < 0.05), with two peaks and one trough. The coverage rates and radiance graphs of PHI and %p2PSA were more distinctive than those of tPSA and the other markers. In subjects older than 69 years, PHI and %p2PSA both began to decrease, approximately 10 years earlier than the decrease in tPSA. Our results suggest that the clinical diagnosis of prostate cancer using PSA should be investigated more comprehensively based on patient age. Moreover, %p2PSA and PHI could be considered as earlier markers that may be more suitable than PSA alone.