Surface and Global Proteome Analyses Identify ENPP1 and Other Surface Proteins as Actionable Immunotherapeutic Targets in Ewing Sarcoma.

Purpose: Ewing sarcoma is the second most common bone sarcoma in children, with 1 case per 1.5 million in the United States. Although the survival rate of patients diagnosed with localized disease is approximately 70%, this decreases to approximately 30% for patients with metastatic disease and only approximately 10% for treatment-refractory disease, which have not changed for decades.

Mass spectrometry redefines optimal testosterone thresholds in prostate cancer patients undergoing androgen deprivation therapy.

Background: Androgen deprivation therapy (ADT) is the standard of care for prostate cancer treatment. Studies suggest that patients with testosterone levels below 0.7 nM have a longer time to castration resistance.

Extensive Alteration of Androgen Precursor Levels After Castration in Prostate Cancer Patients and Their Association With Active Androgen Level.

Purpose: Dihydrotestosterone and testosterone are thought to be major contributors of prostate cancer progression and resistance. We studied the modulation of 15 circulating steroids by castration and their association with dihydrotestosterone and testosterone levels.

Materials Methods: A total of 116 serum samples were collected from 99 prostate cancer patients and categorized as eugonadal, castration-sensitive prostate cancer, castration-resistant prostate cancer, or castration-resistant prostate cancer under abiraterone acetate.

Extracellular Vesicles in Reprogramming of the Ewing Sarcoma Tumor Microenvironment.

Ewing sarcoma (EwS) is a highly aggressive cancer and the second most common malignant bone tumor of children and young adults. Although patients with localized disease have a survival rate of approximately 75%, the prognosis for patients with metastatic disease remains dismal (<30%) and has not improved in decades. Standard-of-care treatments include local therapies such as surgery and radiotherapy, in addition to poly-agent adjuvant chemotherapy, and are often associated with long-term disability and reduced quality of life.

Extragonadal Steroids Contribute Significantly to Androgen Receptor Activity and Development of Castration Resistance in Recurrent Prostate Cancer after Primary Therapy.

Purpose: Beyond testosterone, several steroids contribute to the activation of the androgen receptor pathway, but their relative contributions to the activation of the androgen receptor signaling axis in patients with castrated prostate cancer remain unknown.

Materials And Methods: Serum levels of 9 steroids were measured by mass spectrometry from continuously castrated patients of the PR.7 study (219) and from the PCA24 cohort (116).

Plasma extracellular vesicles as phenotypic biomarkers in prostate cancer patients.

Background: The development of phenotypic biomarkers to aid the selection of treatment for patients with castrate-resistant prostate cancer (CRPC) is an important priority. Plasma exosomes have excellent potential as real-time biomarkers to characterize the tumor because they are easily accessible in the blood and contain DNA, RNA, and protein from the parent cell. This study aims to investigate the characteristics of putative prostate-specific plasma extracellular vesicle (EV) markers and their relationship with clinical outcomes.

Discordance between testosterone measurement methods in castrated prostate cancer patients.

Failure to suppress testosterone below 0.7 nM in castrated prostate cancer patients is associated with poor clinical outcomes. Testosterone levels in castrated patients are therefore routinely measured.

Endogenous Protein Interactome of Human UDP-Glucuronosyltransferases Exposed by Untargeted Proteomics.

The conjugative metabolism mediated by UDP-glucuronosyltransferase enzymes (UGTs) significantly influences the bioavailability and biological responses of endogenous molecule substrates and xenobiotics including drugs. UGTs participate in the regulation of cellular homeostasis by limiting stress induced by toxic molecules, and by controlling hormonal signaling networks. Glucuronidation is highly regulated at genomic, transcriptional, post-transcriptional and post-translational levels.

Investigation of the In Vitro and In Vivo efficiency of RM-532-105, a 17β-hydroxysteroid dehydrogenase type 3 inhibitor, in LAPC-4 prostate cancer cell and tumor models.

In the fight against androgen-sensitive prostate cancer, the enzyme 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) is an attractive therapeutic target considering its key role in the formation of androgenic steroids. In this study, we attempted to assess the in vivo efficacy of the compound RM-532-105, an androsterone derivative developed as an inhibitor of 17β-HSD3, in the prostate cancer model of androgen-sensitive LAPC-4 cells xenografted in nude mice. RM-532-105 did not inhibit the tumor growth induced by 4-androstene-3,17-dione (4-dione); rather, the levels of the androgens testosterone (T) and dihydrotestosterone (DHT) increased within the tumors.

Cross-Talk between Alternatively Spliced UGT1A Isoforms and Colon Cancer Cell Metabolism.

Alternative splicing at the human glucuronosyltransferase 1 gene locus (UGT1) produces alternate isoforms UGT1A_i2s that control glucuronidation activity through protein-protein interactions. Here, we hypothesized that UGT1A_i2s function as a complex protein network connecting other metabolic pathways with an influence on cancer cell metabolism. This is based on a pathway enrichment analysis of proteomic data that identified several high-confidence candidate interaction proteins of UGT1A_i2 proteins in human tissues-namely, the rate-limiting enzyme of glycolysis pyruvate kinase (PKM), which plays a critical role in cancer cell metabolism and tumor growth.

Steroidogenic germline polymorphism predictors of prostate cancer progression in the estradiol pathway.

Purpose: Reliable biomarkers that predict prostate cancer outcomes are urgently needed to improve and personalize treatment approaches. With this goal in mind, we individually and collectively appraised common genetic polymorphisms related to estradiol metabolic pathways to find prostate cancer prognostic markers.

Methods: The genetic profiles of 526 men with organ-confined prostate cancer were examined to find common genetic polymorphisms related to estradiol metabolic pathways and these findings were replicated in a cohort of 213 men with more advanced disease (follow-up time for both cohorts, >7.

Importance of 5α-reductase gene polymorphisms on circulating and intraprostatic androgens in prostate cancer.

Purpose: Polymorphisms in the genes SRD5A1 and SRD5A2 encoding androgen biosynthetic 5α-reductase enzymes have been associated with an altered risk of biochemical recurrence after radical prostatectomy in localized prostate cancer.

Experimental Design: To gain potential insights into SRD5A biologic effects, we examined the relationship between SRD5A prognostic markers and endogenous sex-steroid levels measured by mass spectrometry in plasma samples and corresponding prostatic tissues of patients with prostate cancer.

Results: We report that five of the seven SRD5A markers differentially affect sex-steroid profiles of dihydrotestosterone and its metabolites in both the circulation and prostatic tissues of patients with prostate cancer.

Dual roles for splice variants of the glucuronidation pathway as regulators of cellular metabolism.

Transcripts of the UGT1A gene, encoding half of human UDP-glucuronosyltransferase (UGT) enzymes, undergo alternative splicing, resulting in active enzymes named isoforms 1 (i1s) and novel truncated isoforms 2 (i2s). Here, we investigated the effects of depleting endogenous i2 on drug response and attempted to unveil any additional biologic role(s) for the truncated novel UGT proteins. We used an integrated systems biology approach that combines RNA interference with unbiased global genomic and proteomic screens, and used HT115 colorectal cancer cells as a model.

The relative protein abundance of UGT1A alternative splice variants as a key determinant of glucuronidation activity in vitro.

Alternative splicing (AS) is one of the most significant components of the functional complexity of human UDP-glucuronosyltransferase enzymes (UGTs), particularly for the UGT1A gene, which represents one of the best examples of a drug-metabolizing gene regulated by AS. Shorter UGT1A isoforms [isoform 2 (i2)] are deficient in glucuronic acid transferase activity but function as negative regulators of enzyme activity through protein-protein interaction. Their abundance, relative to active UGT1A enzymes, is expected to be a determinant of the global transferase activity of cells and tissues.

Molecular markers in key steroidogenic pathways, circulating steroid levels, and prostate cancer progression.

Purpose: Prostate cancer is a heterogeneous genetic disease, and molecular methods for predicting prognosis in patients with aggressive form of the disease are urgently needed to better personalize treatment approaches. The objective was to identify host genetic variations in candidate steroidogenic genes affecting hormone levels and prostate cancer progression.

Experimental Design: The study examined two independent cohorts composed of 526 Caucasian men with organ-confined prostate cancer and 601 Taiwanese men on androgen-deprivation therapy.

Protein-protein interactions between the bilirubin-conjugating UDP-glucuronosyltransferase UGT1A1 and its shorter isoform 2 regulatory partner derived from alternative splicing.

The oligomerization of UGTs [UDP (uridine diphosphate)-glucuronosyltransferases] modulates their enzyme activities. Recent findings also indicate that glucuronidation is negatively regulated by the formation of inactive oligomeric complexes between UGT1A enzymes [i1 (isoform 1)] and an enzymatically inactive alternatively spliced i2 (isoform 2). In the present paper, we assessed whether deletion of the UGT-interacting domains previously reported to be critical for enzyme function might be involved in i1-i2 interactions.

Immunohistochemical expression of conjugating UGT1A-derived isoforms in normal and tumoral drug-metabolizing tissues in humans.

Glucuronidation by UDP-glucuronyltransferase (UGT) enzymes is the prevailing conjugative pathway for the metabolism of both xenobiotics and endogenous compounds. Alterations in this pathway, such as those generated by common genetic polymorphisms, have been shown to significantly impact on the health of individuals, influencing cancer susceptibility, responsiveness to drugs and drug-induced toxicity. Alternative usage of terminal exons leads to UGT1A-derived splice variants, namely the classical and enzymatically active isoforms 1 (i1) and the novel enzymatically inactive isoforms 2 (i2).

Alternatively spliced products of the UGT1A gene interact with the enzymatically active proteins to inhibit glucuronosyltransferase activity in vitro.

UDP-glucuronosyltransferases (UGTs) are major mediators in conjugative metabolism. Current data suggest that UGTs, which are anchored in the endoplasmic reticulum membrane, can oligomerize with each other and/or with other metabolic enzymes, a process that may influence their enzymatic activities. We demonstrated previously that the UGT1A locus encodes previously unknown isoforms (denoted "i2"), by alternative usage of the terminal exon 5.