Liquid Biopsy Based Circulating Biomarkers in Metastatic Prostate Cancer

Performance comparison of streptavidin magnetic beads for epcam expressing cancer cell lines for circulating tumor cell (CTC) enrichment in a flow-through immunomagnetic system

Circulating tumor cells (CTCs) are important biomarkers for cancer diagnosis and treatment monitoring. However, their scarcity limits their utility as current enrichment techniques are hampered by low volume throughput and/or the inability to capture CTCs with low target antigen densities. Our group previously reported a device capable of processing samples in a flow manner using an optimized Halbach array to enhance the capture of low EpCAM-expressing cells (Flow-through Immunomagnetic CTC Enrichment system). In this study, we tested the capture efficiency of eight commercially available streptavidin magnetic beads using this device to identify the most suitable bead. Results indicate that using this system, the best-performing magnetic beads are in the ~ 100 to ~ 150 nm size range. Considering the combination of binding efficiency and final sample purity, we found that among the beads tested in combination with biotinylated anti-EpCAM, MojoSort Streptavidin Nanobeads performed the best, with high capture efficiencies for both the high EpCAM expressing LNCaP and low EpCAM expressing PC3-9 cell lines. For CTC enrichment from the blood of cancer patients, reducing the number of WBCs co-enriched with these beads will be essential, especially when processing large-volume samples acquired, for instance, through diagnostic leukapheresis to overcome the limitations caused by the scarcity of CTCs.

Clinical significance of stratifying prostate cancer patients through specific circulating genes

Patient stratification remains a challenge for optimal treatment of prostate cancer (PCa). This clinical heterogeneity implies intra-tumoural heterogeneity, with different prostate epithelial cell subtypes not all targeted by current treatments. We reported that such cell subtypes are traceable in liquid biopsies through representative transcripts. Expanding on this concept, we included 57 genes representing cell subtypes, drug targets and relevant to resistance as non-invasive biomarkers for stratification. This panel was tested by RT-qPCR (quantitative reverse transcription polymerase chain reaction) in blood of controls and different categories of PCa patients. Overall, circulating transcripts showed predictive value throughout the disease. Those with aggressive pathological features such as intra-ductal carcinoma at diagnosis showed more genes over-expressed. In metastatic patients, signatures of subtypes or resistance were associated with treatments, progression-free survival and overall survival. Altogether, testing markers of cell diversity, an intrinsic feature of tumours, and drug targets via liquid biopsies represents a valuable means to stratify patients and predict responses to current or new therapeutic modalities. Over-expressed drug target genes suggest potential benefit from targeted treatments, justifying new clinical trials to offer patient-tailored strategies to eventually impact on PCa mortality.

Cell-free DNA aneuploidy score as a dynamic early response marker in prostate cancer

Cell-free circulating tumor DNA (ctDNA) has emerged as a promising biomarker for response evaluation in metastatic castration-resistant prostate cancer (mCRPC). The current study evaluated the modified fast aneuploidy screening test-sequencing system (mFast-SeqS), a quick, tumor-agnostic and affordable ctDNA assay that requires a small input of DNA, to generate a genome-wide aneuploidy (GWA) score in mCRPC patients, and correlated this to matched metastatic tumor biopsies. In this prospective multicenter study, GWA scores were evaluated from blood samples of 196 mCRPC patients prior to treatment (baseline) with taxanes (docetaxel and cabazitaxel) and androgen receptor signaling inhibitors (ARSI; abiraterone and enzalutamide), and from 74 mCRPC patients at an early timepoint during treatment (early timepoint; median 21 days). Z-scores per chromosome arm were tested for their association with tumor tissue genomic alterations. We found that a high tumor load in blood (GWAhigh) at baseline was associated with poor response to ARSI [HR: 2.63 (95% CI: 1.86-3.72) P < 0.001] but not to taxanes. Interestingly, GWAhigh score at the early timepoint was associated with poor response to both ARSIs [HR: 6.73 (95% CI: 2.60-17.42) P < 0.001] and taxanes [2.79 (95% CI: 1.34-5.78) P = 0.006]. A significant interaction in Cox proportional hazards analyses was seen when combining GWA status and type of treatment (at baseline P = 0.008; early timepoint P = 0.018). In summary, detection of ctDNA in blood by mFast-SeqS is cheap, fast and feasible, and could be used at different timepoints as a potential predictor for outcome to ARSI and taxane treatment in mCRPC.

Secretome Analysis of Prostate Cancer Cell Lines Reveals Cell Cycle-Dependent PSA Secretion and Potential Biomarkers

Background: Metastatic prostate cancer (mPCa) is marked by heterogeneity and therapy resistance, which arise from prolonged therapy regimens. This heterogeneity is reflected in various morphologic and genetic characteristics, biomarker expression, and other molecular mechanisms, thereby contributing to the complexity of the disease. Methods: To investigate tumor heterogeneity, the effects of androgen targeting therapy (ADT) on single-cell PSA secretion was assessed by analyzing the prostate cancer cell lines using a modified ELISpot platform. The FACS and cytospin techniques were employed to understand the influence of the cell cycle on PSA secretion patterns. Additionally, a proteome array was used to identify potential biomarkers from different PCa cell lines with varying metastatic potential. Results: Among the various PCa cell lines examined, PSA expression and secretion could be visualized only from the LNCaPs. PSA secretion from circulating tumor cells (CTCs) further confirmed the validity of this assay. These LNCaPs exhibited heterogeneity in single-cell intracellular and extracellular PSA expression and in their ADT responses. LNCaPs in the G1 phase showed higher PSA secretion than in the S or G2/M phase. Apart from PSA, Cathepsin D, Progranulin, IL-8, Serpin E1, and Enolase 2 were identified as secretome markers from the metastatic PCa cell lines. Conclusions: We observed variability in PSA secretion in LNCaP in response to anti-androgen treatment and a cell cycle-dependent secretion pattern. The notable presence of Progranulin and Cathepsin D in metastatic cell lines makes them promising candidates for use in multiplexing and single-cell platforms, potentially advancing our understanding and treatment of this disease.

Adaptive Treatment of Metastatic Prostate Cancer Using Generative Artificial Intelligence

Despite the expanding therapeutic options available to cancer patients, therapeutic resistance, disease recurrence, and metastasis persist as hallmark challenges in the treatment of cancer. The rise to prominence of generative artificial intelligence (GenAI) in many realms of human activities is compelling the consideration of its capabilities as a potential lever to advance the development of effective cancer treatments. This article presents a hypothetical case study on the application of generative pre-trained transformers (GPTs) to the treatment of metastatic prostate cancer (mPC). The case explores the design of GPT-supported adaptive intermittent therapy for mPC. Testosterone and prostate-specific antigen (PSA) are assumed to be repeatedly monitored while treatment may involve a combination of androgen deprivation therapy (ADT), androgen receptor-signalling inhibitors (ARSI), chemotherapy, and radiotherapy. The analysis covers various questions relevant to the configuration, training, and inferencing of GPTs for the case of mPC treatment with a particular attention to risk mitigation regarding the hallucination problem and its implications to clinical integration of GenAI technologies. The case study provides elements of an actionable pathway to the realization of GenAI-assisted adaptive treatment of metastatic prostate cancer. As such, the study is expected to help facilitate the design of clinical trials of GenAI-supported cancer treatments.

Validation of an artificial intelligence-based prognostic biomarker in patients with oligometastatic Castration-Sensitive prostate cancer

BACKGROUND

There is a need for clinically actionable prognostic and predictive tools to guide the management of oligometastatic castration-sensitive prostate cancer (omCSPC).

METHODS

This is a multicenter retrospective study to assess the prognostic and predictive performance of a multimodal artificial intelligence biomarker (MMAI; the ArteraAI Prostate Test) in men with omCSPC (n = 222). The cohort also included 51 patients from the STOMP and ORIOLE phase 2 clinical trials which randomized patients to observation versus metastasis-directed therapy (MDT). MMAI scores were computed from digitized histopathology slides and clinical variables. Overall survival (OS) and time to castration-resistant prostate cancer (TTCRPC) were assessed for the entire cohort from time of diagnosis. Metastasis free survival (MFS) was assessed for the trial cohort from time of randomization.

RESULTS

In the overall cohort, patients with a high MMAI score had significantly worse OS (HR = 6.46, 95 % CI = 1.44-28.9; p = 0.01) and shorter TTCRPC (HR = 2.07, 95 % CI = 1.15-3.72; p = 0.015). In a multivariable Cox model, MMAI score remained the only variable significantly associated with OS (HR = 6.51, 95 % CI = 1.32-32.2; p = 0.02). In the subset of patients randomized in the STOMP and ORIOLE trials, high MMAI score corresponded to improved MFS with MDT (p = 0.039) compared to patients with a low score, with pinteraction = 0.04.

CONCLUSION

The ArteraAI MMAI biomarker is prognostic for OS and TTCRPC among patients with omCSPC and may predict for response to MDT. Further work is needed to validate the MMAI biomarker in a broader mCSPC cohort.

Extravasation of immune and tumor cells from an endothelial perspective

Crossing the vascular endothelium is a necessary stage for circulating cells aiming to reach distant organs. Leukocyte passage through the endothelium, known as transmigration, is a multistep process during which immune cells adhere to the vascular wall, migrate and crawl along the endothelium until they reach their exit site. Similarly, circulating tumor cells (CTCs), which originate from the primary tumor or reseed from early metastatic sites, disseminate using the blood circulation and also must cross the endothelial barrier to set new colonies in distant organs. CTCs are thought to mimic arrest and extravasation utilized by leukocytes; however, their extravasation also requires processes that, from an endothelial perspective, are specific to cancer cells. Although leukocyte extravasation relies on maintaining endothelial impermeability, it appears that cancer cells can indoctrinate endothelial cells into promoting their extravasation independently of their normal functions. In this Review, we summarize the common and divergent mechanisms of endothelial responses during extravasation of leukocytes (in inflammation) and CTCs (in metastasis), and highlight how these might be leveraged in the development of anti-metastatic treatments.

Therapeutic response and safety of radioligand therapy with 177Lu-PSMA-617 in metastatic castration-resistant prostate cancer patients

Prostate cancer is one of the most common cancers and leading cause of death due to cancer across the globe. This persuaded researchers to devise innovative treatment modalities that may prove effective, safe, and demonstrate better outcomes in terms of patient morbidity and survival. The advancement in theranostics such as lutetium-177 (177Lu)-PSMA-617 radioligand therapies can target prostate cancer cells causing negligible or no damage to most of the normal tissues in patients. It has been proven to effectively improve the quality of life and progression-free survival. In this study, stage IV metastatic castration-resistant prostate cancer patients were treated with 177Lu-PSMA-617, and the therapeutic response and safety of 177Lu-PSMA-617 radioligand therapy were evaluated six months after the treatment. Additionally, molecular docking studies were also conducted to find the possible mechanism at the molecular level that causes the effectiveness of 177Lu-PSMA-617 in prostate cancer.

Advances in metastatic prostate cancer circulating tumor cell enrichment technologies and clinical studies

Circulating tumor cells (CTCs) have emerged as a pivotal tool that enables molecular interrogation of patient tumor cells and association with clinical outcomes. In prostate cancer specifically, where tumor biopsies from patients with bone metastasis are extremely challenging, CTCs offer a viable and established source of tumor "biopsy". While the prognostic value of CTC enumeration in metastatic prostate cancer is established, there is a compelling need for molecular CTC characterization for effective patient stratification and disease management. The clinical utility of CTCs has been advanced by the evolution of enrichment technologies and their molecular characterization. Enrichment technologies have evolved from strictly EpCAM-based enrichment to antigen-agnostic enrichment, while their clinical utility has evolved from enumeration to advanced downstream analyses including CTC proteomics, transcriptomics and genomics. This chapter offers a comprehensive overview of recent advancements in CTC enrichment and analytical technologies while highlighting pivotal clinical studies in prostate cancer, that utilize CTCs to determine the molecular basis of clinical response and resistance, to assist in disease management and treatment customization.

Liquid biopsy to personalize treatment for metastatic prostate cancer

Liquid biopsy is an innovative approach that provides a more complete understanding of treatment response and prognosis in monitoring metastatic prostate cancer. It complements invasive tissue biopsy and involves the assessment of various biomarkers in body fluids such as blood, semen, and urine. Liquid biopsy analyzes circulating tumor cells, extracellular vesicles, circulating tumor DNA, and the secretome. This is particularly important given the heterogeneity of prostate cancer and the need for better prognostic biomarkers. Liquid biopsy can personalize the treatment of homonosensitive and castration-resistant metastatic prostate cancer by acting as a predictive and prognostic tool. This review discusses various biomarkers, assay techniques, and potential applications in daily clinical practice, highlighting the exciting possibilities that this emerging field holds for improving patient outcomes.

Secretome processing for proteomics: A methods comparison

The cancer cell secretome comprises a treasure-trove for biomarkers since it reflects cross-talk between tumor cells and their surrounding environment with high detectability in biofluids. In this study, we evaluated six secretome sample processing workflows coupled to single-shot mass spectrometry: (1) Protein concentration by ultrafiltration with a molecular weight cut-off (MWCO) filter and sample preparation through in-gel digestion (IGD); (2) Acetone protein precipitation coupled to IGD; (3) MWCO filter-based protein concentration followed by to in-solution digestion (ISD); (4) Acetone protein precipitation coupled to ISD; (5) Direct ISD; (6) Secretome lyophilization and ISD. To this end, we assessed workflow triplicates in terms of total number of protein identifications, unique identifications, reproducibility of protein identification and quantification and detectability of small proteins with important functions in cancer biology such as cytokines, chemokines, and growth factors. Our findings revealed that acetone protein precipitation coupled to ISD outperformed the other methods in terms of the number of identified proteins (2246) and method reproducibility (correlation coefficient between replicates (r = 0.94, CV = 19%). Overall, especially small proteins such as those from the classes mentioned above were better identified using ISD workflows. Concluding, herein we report that secretome protein precipitation coupled to ISD is the method of choice for high-throughput secretome proteomics via single shot nanoLC-MS/MS.

Feasibility of Monitoring Response to Metastatic Prostate Cancer Treatment with a Methylation-Based Circulating Tumor DNA Approach

BACKGROUND

Metastatic prostate cancer (mPCA) poses challenges in treatment response assessment, particularly in cases where prostate-specific antigen (PSA) levels do not reliably indicate a response. Liquid biopsy, focusing on circulating cell-free DNA (ccfDNA) methylation analysis as a proxy for circulating tumor DNA, offers a non-invasive and cost-effective approach. This study explores the potential of two methylation markers, short stature homeobox 2 (SHOX2) and Septin 9 (SEPT9), as on-mPCA-treatment biomarkers.

METHODS

Plasma samples were collected from 11 mPCA patients undergoing various treatments. Quantitative assessment of hypermethylated SHOX2 (mSHOX2) and SEPT9 (mSEPT9) levels in ccfDNA was conducted through methylation-specific real-time PCR. Early and overall dynamics of PSA, mSHOX2, and mSEPT9 were analyzed. Statistical evaluation employed Wilcoxon tests.

RESULTS

mSHOX2 demonstrated a significant decline post-treatment in patients with a radiographic treatment response as well as in an early treatment setting. mSEPT9 and PSA exhibited non-significant declines. In individual cases, biomarker dynamics revealed unique patterns compared to PSA.

DISCUSSION

mSHOX2 and mSEPT9 exhibit dynamics on mPCA treatment. This proof-of-concept study lays the groundwork for further investigation into these markers as valuable additions to treatment response monitoring in mPCA. Further validation in larger cohorts is essential for establishing clinical utility.

Clinical Significance of Extracellular Vesicles in Prostate and Renal Cancer

Extracellular vesicles (EVs)-including apoptotic bodies, microvesicles, and exosomes-are released by almost all cell types and contain molecular footprints from their cell of origin, including lipids, proteins, metabolites, RNA, and DNA. They have been successfully isolated from blood, urine, semen, and other body fluids. In this review, we discuss the current understanding of the predictive value of EVs in prostate and renal cancer. We also describe the findings supporting the use of EVs from liquid biopsies in stratifying high-risk prostate/kidney cancer and advanced disease, such as castration-resistant (CRPC) and neuroendocrine prostate cancer (NEPC) as well as metastatic renal cell carcinoma (RCC). Assays based on EVs isolated from urine and blood have the potential to serve as highly sensitive diagnostic studies as well as predictive measures of tumor recurrence in patients with prostate and renal cancers. Overall, we discuss the biogenesis, isolation, liquid-biopsy, and therapeutic applications of EVs in CRPC, NEPC, and RCC.

mFast-SeqS-based aneuploidy score in circulating cell-free DNA is a prognostic biomarker in prostate cancer

Multiple prognostic biomarkers, including circulating tumour cell (CTC) counts, exist in metastatic castration-resistant prostate cancer (mCRPC) patients, but none of them have been implemented into daily clinical care. The modified fast aneuploidy screening test-sequencing system (mFast-SeqS), which yields a genome-wide aneuploidy score, is able to reflect the fraction of cell-free tumour DNA (ctDNA) within cell-free DNA (cfDNA) and may be a promising biomarker in mCRPC. In this study, we investigated the prognostic value of dichotomized aneuploidy scores (< 5 vs. ≥ 5) as well as CTC counts (< 5 vs. ≥ 5) in 131 mCRPC patients prior to treatment with cabazitaxel. We validated our findings in an independent cohort of 50 similarly treated mCRPC patients. We observed that, similar to the dichotomized CTC count [HR: 2.92; 95% confidence interval (CI);1.84-4.62], dichotomized aneuploidy scores (HR: 3.24; CI: 2.12-4.94) significantly correlated with overall survival in mCRPC patients. We conclude that a dichotomized aneuploidy score from cfDNA is a prognostic marker for survival in mCRPC patients within our discovery cohort and in an independent mCRPC validation cohort. Therefore, this easy and robust minimally-invasive assay can be readily implemented as a prognostic marker in mCRPC. A dichotomized aneuploidy score might also be used as a stratification factor in clinical studies to account for tumour load.

Prostate Cancer: Genetics, Epigenetics and the Need for Immunological Biomarkers

Epidemiological data highlight prostate cancer as a significant global health issue, with high incidence and substantial impact on patients' quality of life. The prevalence of this disease is associated with various factors, including age, heredity, and race. Recent research in prostate cancer genetics has identified several genetic variants that may be associated with an increased risk of developing the disease. However, despite the significance of these findings, genetic markers for prostate cancer are not currently utilized in clinical practice as reliable indicators of the disease. In addition to genetics, epigenetic alterations also play a crucial role in prostate cancer development. Aberrant DNA methylation, changes in chromatin structure, and microRNA (miRNA) expression are major epigenetic events that influence oncogenesis. Existing markers for prostate cancer, such as prostate-specific antigen (PSA), have limitations in terms of sensitivity and specificity. The cost of testing, follow-up procedures, and treatment for false-positive results and overdiagnosis contributes to the overall healthcare expenditure. Improving the effectiveness of prostate cancer diagnosis and prognosis requires either narrowing the risk group by identifying new genetic factors or enhancing the sensitivity and specificity of existing markers. Immunological biomarkers (both circulating and intra-tumoral), including markers of immune response and immune dysfunction, represent a potentially useful area of research for enhancing the diagnosis and prognosis of prostate cancer. Our review emphasizes the need for developing novel immunological biomarkers to improve the diagnosis, prognosis, and management of prostate cancer. We highlight the most recent achievements in the identification of biomarkers provided by circulating monocytes and tumor-associated macrophages (TAMs). We highlight that monocyte-derived and TAM-derived biomarkers can enable to establish the missing links between genetic predisposition, hormonal metabolism and immune responses in prostate cancer.

Large tumour-derived extracellular vesicles as prognostic indicators of metastatic cancer patient survival

Extracellular vesicles (EVs) are released by all cells and produced at particularly high levels by many cancer cells, often inducing pro-tumorigenic effects. Since these cancer EVs carry tumour proteins and RNAs, they can potentially be used at biomarkers. The heterogeneity of surface markers and cargos carried by EVs, however, presents some challenges to developing such approaches. Nanou et al. [1] found that automated counting of large tumour-derived EVs (tdEVs) performed at least as effectively as counting circulating tumour-derived cells (CTCs) and with higher sensitivity, in distinguishing the survival of patients with castration-resistant prostate cancer (CRPC), metastatic colorectal cancer (mCRC) and metastatic breast cancer (MBC), but not for non-small cell lung cancer (NSCLC). Subsequent work has suggested that these tdEVs may also be used to assess tumour subtype and that the number of large EVs produced by endothelial cells can also be increased in cancer patients. While by itself, the tdEV imaging approach used by Nanou et al. [1] is not specific enough to predict the survival of individual patients, in combination with other EV-associated assays, this test, perhaps enhanced through the inclusion of other tumour antigens, could prove invaluable in predicting cancer survival and other outcomes in the clinic.

Principle Superiority and Clinical Extensibility of 2D and 3D Charged Nanoprobe Detection Platform Based on Electrophysiological Characteristics of Circulating Tumor Cells

The electrical characteristic of cancer cells is neglected among tumor biomarkers. The development of nanoprobes with opposing charges for monitoring the unique electrophysiological characteristics of cancer cells. Micro-nano size adsorption binding necessitates consideration of the nanoprobe's specific surface area. On the basis of the electrophysiological characteristics of circulating tumor cells (CTCs), clinical application and performance assessment are determined. To demonstrate that cancer cells have a unique pattern of electrophysiological patterns compared to normal cells, fluorescent nanoprobes with opposing charges were developed and fabricated. Graphene oxide (GO) was used to transform three-dimensional (3D) nanoprobes into two-dimensional (2D) nanoprobes. Compare 2D and 3D electrophysiological magnetic nanoprobes (MNP) in clinical samples and evaluate the adaptability and development of CTCs detection based on cell electrophysiology. Positively charged nanoprobes rapidly bind to negatively charged cancer cells based on electrostatic interactions. Compared to MNPs(+) without GO, the GO/MNPs(+) nanoprobe is more efficient and uses less material to trap cancer cells. CTCs can be distinguished from normal cells that are fully unaffected by nanoprobes by microscopic cytomorphological inspection, enabling the tracking of the number and pathological abnormalities of CTCs in the same patient at various chemotherapy phases to determine the efficacy of treatment. The platform for recognizing CTCs on the basis of electrophysiological characteristics compensates for the absence of epithelial biomarker capture and size difference capture in clinical performance. Under the influence of electrostatic attraction, the binding surface area continues to influence the targeting of cancer cells by nanoprobes. The specific recognition and detection of nanoprobes based on cell electrophysiological patterns has enormous potential in the clinical diagnosis and therapeutic monitoring of cancer.

Biomarkers for the Detection and Risk Stratification of Aggressive Prostate Cancer

Current strategies for the clinical management of prostate cancer are inadequate for a precise risk stratification between indolent and aggressive tumors. Recently developed tissue-based molecular biomarkers have refined the risk assessment of the disease. The characterization of tissue biopsy components and subsequent identification of relevant tissue-based molecular alterations have the potential to improve the clinical decision making and patient outcomes. However, tissue biopsies are invasive and spatially restricted due to tumor heterogeneity. Therefore, there is an urgent need for complementary diagnostic and prognostic options. Liquid biopsy approaches are minimally invasive with potential utility for the early detection, risk stratification, and monitoring of tumors. In this review, we focus on tissue and liquid biopsy biomarkers for early diagnosis and risk stratification of prostate cancer, including modifications on the genomic, epigenomic, transcriptomic, and proteomic levels. High-risk molecular alterations combined with orthogonal clinical parameters can improve the identification of aggressive tumors and increase patient survival.

Prognostic significance of lncRNA AP004608.1 in prostate cancer

This study aimed to screen and determine the value of AP004608.1 expression as a biomarker for Prostate cancer (PCa) survival. We investigated the expression and prognosis of AP004608.1 through bioinformatics analysis. Low AP004608.1 expression predicted favorable Overall survival (OS) and Progression-free survival (PFS) in PCa patients, according to the Cancer Genome Atlas (TCGA) database. Cox regression demonstrated that low AP004608.1 expression were in-dependent biomarkers for OS. Moreover, Gene Expression Omnibus (GEO) database was utilized to verify the prognostic role of AP004608.1 in PCa, and the similar results were reached. A meta-analysis revealed that low AP004608.1 expression was closely relevant to better OS. AP004608.1 could constitute a promising prognostic biomarker, and probably plays an important role in PCa.