Biomolecule-functionalized nanoformulations for prostate cancer theranostics

BACKGROUND

Even with the advancement in the areas of cancer nanotechnology, prostate cancer still poses a major threat to men's health. Nanomaterials and nanomaterial-derived theranostic systems have been explored for diagnosis, imaging, and therapy for different types of cancer still, for prostate cancer they have not delivered at full potential because of the limitations like in vivo biocompatibility, immune responses, precise targetability, and therapeutic outcome associated with the nanostructured system.

AIM OF REVIEW

Functionalizing nanomaterials with different biomolecules and bioactive agents provides advantages like specificity towards cancerous tumors, improved circulation time, and modulation of the immune response leading to early diagnosis and targeted delivery of cargo at the site of action.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, we have emphasized the classification and comparison of various nanomaterials based on biofunctionalization strategy and source of biomolecules such that it can be used for possible translation in clinical settings and future developments. This review highlighted the opportunities for embedding highly specific biological targeting moieties (antibody, aptamer, oligonucleotides, biopolymer, peptides, etc.) on nanoparticles which can improve the detection of prostate cancer-associated biomarkers at a very low limit of detection, direct visualization of prostate tumors and lastly for its therapy. Lastly, special emphasis was given to biomimetic nanomaterials which include functionalization with extracellular vesicles, exosomes and viral particles and their application for prostate cancer early detection and drug delivery. The present review paves a new pathway for next-generation biofunctionalized nanomaterials for prostate cancer theranostic application and their possibility in clinical translation.

RecQ helicase BLM regulates prostate cancer cell proliferation and apoptosis

Prostate cancer (PCa) is a common malignant tumor and the second leading cause of morbidity and mortality in men worldwide. Considering the prevalence and effects of PCa in males, an understanding of the molecular mechanisms underlying PCa tumorigenesis are essential and may provide novel therapeutic strategies for treating PCa. Bloom syndrome protein (BLM) is a member of the RecQ helicase family. The major function of BLM is to uncoil the double-stranded DNA structure. It has previously been demonstrated that BLM acts as a ‘genome caretaker’, and dysregulation of BLM function has been implicated in the development of multiple tumor types; however, its potential for inducing PCa tumorigenesis remains undetermined. The present study aimed to explore the function of BLM in PCa progression. Reverse transcription-polymerase chain reaction, immunohistochemistry and western blot analyses were performed to detect the BLM expression pattern in PCa patients and cell lines. The proliferation, and migration and invasion capacities of prostate cells were determined by EdU and Transwell assays following transfection with BLM-targeting short hairpin RNA (shRNA). The expression of BLM was significantly increased in PCa tissues and PC3 cells compared with non-PCa tissues and benign prostatic hyperplasia cells. Knockdown of BLM via shRNA inhibited PCa cell proliferation, and promoted PCa cell apoptosis. Notably, reducing the expression of BLM had no effect on the migration or invasive abilities of PCa cells. These results suggest that downregulation of BLM may alleviate PCa development, providing a novel perspective for PCa tumorigenesis and a potential therapeutic target for PCa.

miRNAs as novel biomarkers in the management of prostate cancer

microRNAs (miRNAs) are small non-coding RNAs that control gene expression posttranscriptionally and are part of the giant non codifying genoma. Cumulating data suggest that miRNAs are promising potential biomarkers for many diseases, including cancer. Prostate cancer (PCa) detection is currently based in the serum prostate-specific antigen biomarker and digital rectal examination. However, these methods are limited by a low predictive value and the adverse consequences associated with overdiagnosis and overtreatment. New biomarkers that could be used for PCa detection and prognosis are still needed. Recent studies have demonstrated that aberrant expressions of microRNAs are associated with the underlying mechanisms of PCa. This review attempts to extensively summarize the current knowledge of miRNA expression patterns, as well as their targets and involvement in PCa pathogenesis. We focused our review in the value of circulating and urine miRNAs as biomarkers in PCa patients, highlighting the existing discrepancies between different studies, probably associated with the important methodological issues related to their quantitation and normalization. The majority of studies have been performed in serum or plasma, but urine obtained after prostate massage appears as a new way to explore the usefulness of miRNAs. Large screening studies to select a miRNA profile have been completed, but bioinformatics tools appear as a new approach to select miRNAs that are relevant in PCa development. Promising preliminary results were published concerning miR-141, miR-375 and miR-21, but larger and prospective studies using standardized methodology are necessary to define the value of miRNAs in the detection and prognosis of PCa.

Emerging biomarkers in the detection and prognosis of prostate cancer

The prostate-specific antigen (PSA) is currently the most used tumor marker in the early detection of the prostate cancer (PCa), despite its low specificity and low negative predictive value. New biomarkers, including urine prostate cancer gene 3 (PCA3) score, Prostate Health Index (PHI), and the four-kallikrein panel, have been investigated during recent years especially with the aim of detecting aggressive PCa. Results suggest the ability of these biomarkers to improve the specificity of PSA in the detection of PCa, although there are not enough results directly comparing these biomarkers to know their complementarity. The relationship with PCa aggressiveness seems to be confirmed for PHI and for the four-kallikrein panel, but not for PCA3 score. However, available results suggest that emerging biomarkers may be useful as part of a multivariable approach for the screening and prognosis of PCa. Nevertheless, larger prospective studies comparing these biomarkers are necessary to evaluate definitely their value in the management of early PCa.

Diagnosis of prostate cancer via nanotechnological approach

Prostate cancer is one of the leading causes of cancer-related deaths among the Caucasian adult males in Europe and the USA. Currently available diagnostic strategies for patients with prostate cancer are invasive and unpleasant and have poor accuracy. Many patients have been overly or underly treated resulting in a controversy regarding the reliability of current conventional diagnostic approaches. This review discusses the state-of-the-art research in the development of novel noninvasive prostate cancer diagnostics using nanotechnology coupled with suggested diagnostic strategies for their clinical implication.

Clinical utility of %p2PSA and prostate health index in the detection of prostate cancer

BACKGROUND

%p2PSA and prostate health index (phi) has shown valuable results in the detection of prostate cancer (PCa), improving the prediction of the aggressiveness of the tumor. The goal of the present study was to evaluate %p2PSA and phi in the detection of PCa, estimating their relationship with the aggressiveness of PCa.

METHODS

A total of 354 patients with positive or negative prostatic biopsy were included. Prospectively, 150 were enrolled and 204 were enrolled retrospectively proceeding from our serum bank.

RESULTS

The best performance was observed for %p2PSA and phi, obtaining an AUC of 0.723 and 0.732, respectively. The highest specificity at sensitivity around 90% was obtained for phi (27.4%). Using the cut-off of 31.94 for phi, a reduction of 19% biopsies could be obtained, while 17 PCa would have been missed, including only four patients with a Gleason score ≥7. Similarly, using a cut-off of 1.21 for %p2PSA, a reduction of 12.7% biopsies could be obtained, while 16 PCa would have been missed, including only four patients with a Gleason score ≥7. Moreover, among patients with PCa, phi (median: 69.75 vs. 48.04) and %p2PSA (median: 2.60 vs. 1.98) values are significantly higher (p<0.0001) in patients with a biopsy Gleason score ≥7.

CONCLUSIONS

Our results confirm previous evaluations, showing similar AUCs and results in sensitivity and specificity to other studies.%p2PSA and phi raise the accuracy in the detection of prostate cancer, reducing the number of unnecessary biopsies and improving the prediction of the aggressiveness of the tumor.

Predictions for the future of kallikrein-related peptidases in molecular diagnostics

Kallikrein-related peptidases (KLKs) form a cancer-related ensemble of serine proteases. This multigene family hosts the most widely used cancer biomarker that is PSA-KLK3, with millions of tests performed annually worldwide. The present report provides an overview of the biomarker potential of the extended KLK family (KLK1-KLK15) in various disease settings and envisages approaches that could lead to additional KLK-driven applications in future molecular diagnostics. Particular focus is given on the inclusion of KLKs into multifaceted cancer biomarker panels that provide enhanced diagnostic, prognostic and/or predictive accuracy in several human malignancies. Such panels have been described so far for prostate, ovarian, lung and colorectal cancers. The role of KLKs as biomarkers in non-malignant disease settings, such as Alzheimer's disease and multiple sclerosis, is also commented upon. Predictions are given on the challenges and future directions regarding clinically oriented KLK research.