Interactive effects of 9-cis-retinoic acid and androgen on proliferation, differentiation, and apoptosis of LNCaP prostate cancer cells

Epigenetic disruption of the RARγ complex impairs its function to bookmark AR enhancer interactions required for enzalutamide sensitivity in prostate cancer

The current study in prostate cancer (PCa) focused on the genomic mechanisms at the cross-roads of pro-differentiation signals and the emergence of lineage plasticity. We explored an understudied cistromic mechanism involving RARγ's ability to govern AR cistrome-transcriptome relationships, including those associated with more aggressive PCa features. The RARγ complex in PCa cell models was enriched for canonical cofactors, as well as proteins involved in RNA processing and bookmarking. Identifying the repertoire of miR-96 bound and regulated gene targets, including those recognition elements marked by m6A, revealed their significant enrichment in the RARγ complex. RARγ significantly enhanced the AR cistrome, particularly in active enhancers and super-enhancers, and overlapped with the binding of bookmarking factors. Furthermore, RARγ expression led to nucleosome-free chromatin enriched with H3K27ac, and significantly enhanced the AR cistrome in G2/M cells. RARγ functions also antagonized the transcriptional actions of the lineage master regulator ONECUT2. Similarly, gene programs regulated by either miR-96 or antagonized by RARγ were enriched in alternative lineages and more aggressive PCa phenotypes. Together these findings reveal an under-investigated role for RARγ, modulated by miR-96, to bookmark enhancer sites during mitosis. These sites are required by the AR to promote transcriptional competence, and emphasize luminal differentiation, while antagonizing ONECUT2.

Repurposed Drugs in Gastric Cancer

Gastric cancer (GC) is one of the major causes of death worldwide, ranking as the fifth most incident cancer in 2020 and the fourth leading cause of cancer mortality. The majority of GC patients are in an advanced stage at the time of diagnosis, presenting a poor prognosis and outcome. Current GC treatment approaches involve endoscopic detection, gastrectomy and chemotherapy or chemoradiotherapy in an adjuvant or neoadjuvant setting. Drug development approaches demand extreme effort to identify molecular mechanisms of action of new drug candidates. Drug repurposing is based on the research of new therapeutic indications of drugs approved for other pathologies. In this review, we explore GC and the different drugs repurposed for this disease.

Characterizing isoform switching events in esophageal adenocarcinoma

Isoform switching events with predicted functional consequences are common in many cancers, but characterization of switching events in esophageal adenocarcinoma (EAC) is lacking. Next-generation sequencing was used to detect levels of RNA transcripts and identify specific isoforms in treatment-naïve esophageal tissues ranging from premalignant Barrett’s esophagus (BE), BE with low- or high-grade dysplasia (BE.LGD, BE.HGD), and EAC. Samples were stratified by histopathology and TP53 mutation status, identifying significant isoform switching events with predicted functional consequences. Comparing BE.LGD with BE.HGD, a histopathology linked to cancer progression, isoform switching events were identified in 75 genes including KRAS, RNF128, and WRAP53. Stratification based on TP53 status increased the number of significant isoform switches to 135, suggesting switching events affect cellular functions based on TP53 mutation and tissue histopathology. Analysis of isoforms agnostic, exclusive, and shared with mutant TP53 revealed unique signatures including demethylation, lipid and retinoic acid metabolism, and glucuronidation, respectively. Nearly half of isoform switching events were identified without significant gene-level expression changes. Importantly, two TP53-interacting isoforms, RNF128 and WRAP53, were significantly linked to patient survival. Thus, analysis of isoform switching events may provide new insight for the identification of prognostic markers and inform new potential therapeutic targets for EAC.

Randomized, Placebo-Controlled Six-Month Intervention Study of Soy Protein Isolate in Men with Biochemical Recurrence after Radical Prostatectomy: A Pilot Study

There is evidence to suggest that soy may be beneficial for prostate cancer patients, but few randomized trials have addressed this. We examined the effect of 6-8 mo soy protein supplementation on prostate specific antigen (PSA) serum levels in men who recurred (PSA > 0.1 ng/ml) within three years of prostatectomy. Sixteen men were randomized to 20 g soy protein (∼24-26/day genistein; ∼40-43/day total isoflavones) or casein placebo. PSA was measured at base line and at 1, 2, 4, and 6-8 mo. Serum genistein levels greatly increased from baseline and cholesterol decreased in the soy group. In both treatment arms PSA increased similarly and PSA doubling times were not different over the 6-8 mo study duration. Two subjects in each group had stable PSA. A literature search for clinical studies of soy, isoflavones, and PSA revealed that supplementation with soy or isoflavones did not affect PSA in virtually all clinical studies identified. Although this study is too small to draw a definitive conclusion on the effect of soy protein on PSA in men with biochemical failure, the null finding in this study is consistent with the results of virtually all reports of soy and soy isoflavones in the literature.

Metabolomics and Proteomics Reveal the Variation of Substances in Apheresis Platelets during Storage and Their Effects on Cancer Cell Proliferation

INTRODUCTION

Apheresis platelets (APs) are clinically and crucially important in the prevention and treatment of bleeding in patients with thrombocytopenia or cancer. However, few researchers have addressed the variation of supernatant metabolites and exosome proteins in APs during storage and their effects on cancer cell proliferation.

OBJECTIVE

This study was designed to explore the change rules of the metabolites and exosomal proteins of APs during storage and their effects on cancer cell proliferation.

METHODS

Metabolomics and proteomics were separately applied to analyze the variation of AP supernatant metabolites and exosomal proteins between freshly prepared day-0 and day-5 terminal-stored APs. Cell counting kit (CCK)-8 assay was performed to detect the effects of AP supernatants and exosomes on the proliferation of cancer cells.

RESULTS

We found that the supernatant metabolites and exosomal proteins in APs were significantly different on day 0 and day 5, and that many differential metabolites and exosomal proteins were associated with cancer characteristics. Furthermore, the day-5 AP supernatants had a greater inhibition of the proliferation of K562, HepG2, and HCT116 cancer cells, but the day-5 AP exosomes had no significant effect on the proliferation of these cancer cells.

CONCLUSION

The variant terminal-stored AP supernatants may inhibit the proliferation of cancer cells but the variant terminal AP exosomes have no effect on cancer cell proliferation.

miR-191 promotes radiation resistance of prostate cancer through interaction with RXRA

Radiation therapy is a common treatment for prostate cancer, however recurrence remains a problem. MicroRNA expression is altered in prostate cancer and may promote therapy resistance. Through bioinformatic analyses of TCGA and CPC-GENE patient cohorts, we identified higher miR-191 expression in tumor versus normal tissue, and increased expression in higher Gleason scores. In vitro and in vivo experiments demonstrated that miR-191 overexpression promotes radiation survival, and contributes to a more aggressive phenotype. Retinoid X receptor alpha, RXRA, was discovered to be a novel target of miR-191, and knockdown recapitulated radioresistance. Furthermore, treatment of prostate cancer cells with the RXRA agonist 9-cis-retinoic acid restored radiosensitivity. Supporting this relationship, patients with high miR-191 and low RXRA abundance experienced quicker biochemical recurrence. Reduced RXRA translated to a higher risk of distant failure after radiotherapy. Notably, this miR-191/RXRA interaction was conserved in a novel primary cell line derived from radiorecurrent prostate cancer. Together, our findings demonstrate that miR-191 promotes prostate cancer survival after radiotherapy, and highlights retinoids as a potential option to improve radiotherapy response.

Retinol palmitate and ascorbic acid: Role in oncological prevention and therapy

Cancer development has been directly related to oxidative stress. During chemotherapy, some cancer patients use dietary antioxidants to avoid nutritional deficiencies due to cancer treatment. Among the antioxidants consumed, there are vitamins, including retinyl palmitate (PR) and ascorbic acid (AA), which have the capacity to reduce free radicals formation, protect cellular structures and maintain the cellular homeostasis. This systematic review evaluated the antioxidant and antitumor mechanisms of retinol palmitate (a derivative of vitamin A) and/or ascorbic acid (vitamin C) in cancer-related studies. Ninety-seven (97) indexed articles in the databases PubMed and Science Direct, published between 2013 and 2017, including 23 clinical studies (5 for every single compound while 13 in interaction) and 74 non-clinical studies (37 for retinol palmitate, 36 for ascorbic acid and 1 in interaction) were considered. Antioxidant and antitumor effects, with controversies over dosage and route of administration, were observed for the test compounds in their isolated form or associated in clinical studies. Prevention of cancer risks against oxidative damage was seen in lower doses of retinol palmitate and/or vitamin C. However, at high doses, they can generate reactive oxygen species, cytotoxicity and apoptosis in test systems. Non-clinical studies using cell lines have allowed understanding the mechanisms related to antioxidants and antitumor effects of the isolated compounds, however, studies on vitamin interactions, acting as antioxidants and/or antitumor are still rare and controversial. More studies, mainly related to modulation of antineoplastic drugs are needed for understanding the risks and benefits of their use during treatment in order to achieve effectiveness in cancer therapy and patient's quality of life.

Metabolomics research on potential role for 9-cis-retinoic acid in breast cancer progression

Deciphering the molecular networks that discriminate organ-confined breast cancer from metastatic breast cancer may lead to the identification of critical biomarkers for breast cancer invasion and aggressiveness. Here metabolomics, a global study of metabolites, has been applied to explore the metabolic alterations that characterize breast cancer progression. We profiled a total of 693 metabolites across 87 serum samples related to breast cancer (46 clinically localized and 41 metastatic breast cancer) and 49 normal samples. These unbiased metabolomic profiles were able to distinguish normal individuals, clinically localized and metastatic breast cancer patients. 9-cis-Retinoic acid, an isomer of all-trans retinoic acid, was identified as a differential metabolite that significantly decreased during breast cancer progression to metastasis, and its levels were also reduced in urine samples from biopsy-positive breast cancer patients relative to biopsy-negative individuals and in invasive breast cancer cells relative to benign MCF-10A cells. The addition of exogenous 9-cis-retinoic acid to MDA-MB-231 cells and knockdown of aldehyde dehydrogenase 1 family member A1, a regulatory enzyme for 9-cis-retinoic acid, remarkably impaired cell invasion and migration, presumably through preventing the key regulator cofilin from activation and inhibiting MMP2 and MMP9 expression. Taken together, our study showed the potential inhibitory role for 9-cis-retinoic acid in breast cancer progression by attenuating cell invasion and migration.

Retinoic acid receptors α and γ are involved in antioxidative protection in renal tubular epithelial cells injury induced by hypoxia/reoxygenation

Renal interstitial fibrosis (RIF) is a common outcome in various chronic kidney diseases. Injury to renal tubular epithelial cell (RTEC) is major link in RIF. Hypoxia is one of the common factors for RTEC damage. Retinoic acid receptors (RARs), RARα, RARβ and RARγ, are evolutionary conserved and pleiotropic proteins that have been involved in various cellular functions, including proliferation, differentiation, apoptosis, and transcription. Recently, we discovered that aberrant expression of RARs was involved in the development of RIF in rats. Here, we investigated the role of RARs in the hypoxia/reoxygenation (HR) damage model in RTEC with virus-based delivery vectors to knockdown or overexpress RARs. Relevant indicators were detected. Our results showed that HR inhibited RARα and RARγ expressions in a time-dependent manner in RTECs; however, the expression of RARβ was not changed obviously. RARα and RARγ overexpression could protect cells from oxidative stress-induced injury by inhibiting HR-induced intracellular superoxide anion (O2-) generation, cell viability and mitochondria membrane potential (MMP) decrease and transforming growth factor β1 (TGF-β1) expression and promoting endogenous antioxidant defense components, superoxide dismutase (SOD) and glutathione (GSH). Meanwhile, inhibition of RARα and RARγ expressions by small interference RNAs (siRNA) resulted in a less resistance of RTEC to HR as shown in increased O2- production and TGF-β1 expression and decreased cell viability, MMP, SOD and GSH levels. These data indicates that RARα and RARγ act as positive regulators to offset oxidative damage and profibrosis cytokine accumulation and therefore has an antioxidative effect.