Comparative proteome analysis identified CD44 as a possible serum marker for docetaxel resistance in castration-resistant prostate cancer

Unveiling the characteristics of D4 and R4 aptamers for their future use in prostate cancer clinical practice

The DNA and RNA aptamers D4 and R4, respectively, emerged from the modification of PC-3 cell-binding aptamer A4. Our objective was to characterize the aptamers in silico and in vitro and begin to identify their target molecules. We represented their structures using computational algorithms; evaluated their binding to several prostate cell lines and their effects on the viability and migration of these cells; and determined their dissociation constant by flow cytometry. We analyzed circulating prostate tumor cells from patients using D4, R4, anti-CD133 and anti-CD44. Finally, the target proteins of both aptamers were precipitated and identified by mass spectrometry to simulate their in silico docking. The aptamers presented similar structures and bound to prostate tumor cells without modifying the cellular parameters studied, but with different affinities. The ligand cells for both aptamers were CD44+, indicating that they could identify cells in the mesenchymal stage of the metastatic process. The possible target proteins NXPE1, ADAM30, and MUC6 need to be further studied to better understand their interaction with the aptamers. These results support the development of new assays to determine the clinical applications of D4 and R4 aptamers in prostate cancer.

Development of a sandwich ELISA to detect circulating, soluble IRAP as a potential disease biomarker

There is growing interest in the use of the enzyme, insulin regulated aminopeptidase (IRAP), as a biomarker for conditions such as cardio-metabolic diseases and ischemic stroke, with upregulation in its tissue expression in these conditions. However, quantification of circulating IRAP has been hampered by difficulties in detecting release of the truncated, soluble form of this enzyme into the blood stream. The current study aimed to develop a sandwich ELISA using novel antibodies directed towards the soluble portion of IRAP (sIRAP), to improve accuracy in detection and quantification of low levels of sIRAP in plasma. A series of novel anti-IRAP antibodies were developed and found to be highly specific for sIRAP in Western blots. A sandwich ELISA was then optimised using two distinct antibody combinations to detect sIRAP in the low nanogram range (16-500 ng/ml) with a sensitivity of 9 ng/ml and intra-assay variability < 10%. Importantly, the clinical validity of the ELISA was verified by the detection of significant increases in the levels of sIRAP throughout gestation in plasma samples from pregnant women. The specific and sensitive sandwich ELISA described in this study has the potential to advance the development of IRAP as a biomarker for certain diseases.

Sequencing impact and prognostic factors in metastatic castration-resistant prostate cancer patients treated with cabazitaxel: A systematic review and meta-analysis

BACKGROUND

Cabazitaxel is an effective treatment of post-docetaxel metastatic castration-resistant prostate cancer (mCRPC). We aimed to assess the sequencing impact and identify prognostic factors of oncologic outcomes in mCRPC patients treated with cabazitaxel.

METHODS

PUBMED, Web of Science, and Scopus databases were searched for articles published before January 2022 according to the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) statement. Studies were deemed eligible if they investigated pretreatment clinical or hematological prognostic factors of overall survival (OS) in mCRPC patients with progression after docetaxel treated with available treatments including cabazitaxel.

RESULTS

Overall, 22 studies were eligible for the meta-analysis. In mCRPC patients treated with docetaxel, subsequent treatment with cabazitaxel was associated with better OS compared to that without cabazitaxel (pooled hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.56-0.89). Among the patients treated with cabazitaxel, several pretreatment clinical features and hematologic biomarkers were associated with worse OS as follows: poor performance status (PS) (pooled HR: 1.92, 95% CI: 1.33-2.77), presence of visceral metastasis (pooled HR: 2.13, 95% CI: 1.62-2.81), symptomatic disease (pooled HR: 1.47, 95% CI: 1.25-1.73), high PSA (pooled HR: 1.76, 95% CI: 1.27-2.44), high alkaline phosphatase (ALP) (pooled HR: 1.45, 95% CI: 1.28-1.65), high lactate dehydrogenase (LDH) (pooled HR: 1.54, 95% CI: 1.00-2.38), high c-reactive protein (CRP) (pooled HR: 4.40, 95% CI: 1.52-12.72), low albumin (pooled HR:1.09, 95% CI: 1.05-1.12) and low hemoglobin (pooled HR:1.55, 95% CI: 1.20-1.99).

CONCLUSIONS

Sequential therapy with cabazitaxel significantly improves OS in post-docetaxel mCRPC patients. In mCRPC patients treated with cabazitaxel, patients with poor PS, visceral metastasis, and symptomatic disease were associated with worse OS. Further, pretreatment high PSA, ALP, LDH or CRP as well as low hemoglobin or albumin, were blood-based prognostic factors for OS. These findings might help guide the clinical decision-making for the use of cabazitaxel and prognostication of its OS benefit.