Thyroid hormone induces cellular senescence in prostate cancer cells through induction of DEC1

The circadian rhythm: A key variable in aging?

The determination of age-related transcriptional changes may contribute to the understanding of health and life expectancy. The broad application of results from age cohorts may have limitations. Altering sample sizes per time point or sex, using a single mouse strain or tissue, a limited number of replicates, or omitting the middle of life can bias the surveys. To achieve higher general validity and to identify less distinctive players, bulk RNA sequencing of a mouse cohort, including seven organs of two strains from both sexes of 5 ages, was performed. Machine learning by bootstrapped variable importance and selection methodology (Boruta) was used to identify common aging features where the circadian rhythms (CiR) transcripts appear as promising age markers in an unsupervised analysis. Pathways of 11 numerically analyzed local network clusters were affected and classified into four major gene expression profiles, whereby CiR and proteostasis candidates were particularly conspicuous with partially opposing changes. In a data-based interaction association network, the CiR-proteostasis axis occupies an exposed central position, highlighting its relevance. The computation of 11,830 individual transcript associations provides potential superordinate contributors, such as hormones, to age-related changes, as in CiR. In hormone-sensitive LNCaP cells, short-term supraphysiologic levels of the sex hormones dihydrotestosterone or estradiol increase the expression of the CiR transcript Bhlhe40 and the associated senescence regulator Cdkn2b (p15). According to these findings, the bilateral dysregulation of CiR appears as a fundamental protagonist of aging, whose transcripts could serve as a biological marker and its restoration as a therapeutic opportunity.

The clock gene BHLHE40 and atypical CCNG2 control androgen-induced cellular senescence as a novel tumor suppressive pathway in prostate cancer

BACKGROUND

The androgen receptor (AR) is a drug target used to inhibit AR and prostate cancer (PCa) growth. Surprisingly, treatment with supraphysiological androgen level (SAL), used in bipolar androgen therapy, inhibits growth of PCa suggesting a tumor-suppressive activity by SAL. SAL was shown to induce cellular senescence in PCa.

METHODS

RNA-seq and transcriptome analysis, ChIP-seq, human 3D PCa spheroids, mouse xenografted castration-resistant PCa, knockdown and overexpression, Co-immunoprecipitation (Co-IP), translocation analysis, immune detection, qRT-PCR, protein-protein interaction modelling.

RESULTS

Here, mice xenografts with castration-resistant PCa tumors show that SAL inhibits cancer growth in vivo suggesting that SAL activates a tumor-suppressive mechanism. RNA-seq and ChIP-seq revealed the clock gene BHLHE40 is a novel direct AR target. Compared to adjacent human prostate tissues, the expression of BHLHE40 is reduced in PCa tumors and associated with reduced survival. Knockdown suggests that BHLHE40 mediates SAL-induced cellular senescence including tumor spheroids. Interestingly, a large overlap of differentially expressed gene sets was identified between BHLHE40 and SAL leading to the identification of four classes of SAL-BHLHE40 transcriptome landscapes. Co-IP and modelling suggest binding of BHLHE40 to AR and their co-translocation into nucleus by SAL treatment. Further, RNA-seq and ChIP-seq analysis indicate that the atypical tumor suppressive cyclin G2 emerged as a novel downstream target of BHLHE40 and a mediator of SAL-induced cellular senescence.

CONCLUSIONS

The data provide evidence of the tumor suppressive activity of SAL and a novel signaling by the AR-BHLHE40-CCNG2 axis for androgen-induced cellular senescence, linking circadian rhythm factor to androgen signaling as a novel tumor suppressive pathway.

In vitro combination effects of plant-derived quercetin with synthetic bicalutamide on prostate cancer and normal cell lines: in silico comparison

Prostate cancer is the second most frequent and the fifth greatest cause of death in men. Although diet has been connected to the prevalence of cancer in addition to other factors, the relation between cancer and prevention is weak. Treatment options are at risk due to cell resistance. To identify new combinations, we tried plant-derived quercetin with bicalutamide on cell lines. To determine the cytotoxicity and apoptotic potential of plant-derived quercetin and its combination, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] and dual stain assays were performed. In silico protein-ligand interaction was performed to support the in vitro findings. A thin layer, column, and high-performance chromatography were used to purify quercetin along with an authentic sample. In the cytotoxic study, quercetin was minimized by 80% similar to bicalutamide and a combination of quercetin and bicalutamide by 50% when compared to controls by 2%. Quercetin and bicalutamide showed a similar binding affinity for androgen receptors (9.7 and 9.8), hub genes (10.8 and 10.0), and a few other PCa-related genes (9.4 and 9.1). We propose to conclude that the combination of quercetin plus bicalutamide can be used for chemotherapy if additional in vivo studies are conducted. The intake of foods high in polyphenolic compounds can help to prevent prostate cancer. Examination of quercetin on several cell lines will provide a definite conclusion to combat cancers.

The BHLHE40‒PPM1F‒AMPK pathway regulates energy metabolism and is associated with the aggressiveness of endometrial cancer

BHLHE40 is a basic helix-loop-helix transcription factor that is involved in multiple cell activities including differentiation, cell cycle, and epithelial-to-mesenchymal transition. While there is growing evidence to support the functions of BHLHE40 in energy metabolism, little is known about the mechanism. In this study, we found that BHLHE40 expression was downregulated in cases of endometrial cancer of higher grade and advanced disease. Knockdown of BHLHE40 in endometrial cancer cells resulted in suppressed oxygen consumption and enhanced extracellular acidification. Suppressed pyruvate dehydrogenase (PDH) activity and enhanced lactated dehydrogenase (LDH) activity were observed in the knockdown cells. Knockdown of BHLHE40 also led to dephosphorylation of AMPKα Thr172 and enhanced phosphorylation of pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1) Ser293 and lactate dehydrogenase A (LDHA) Tyr10. These results suggested that BHLHE40 modulates PDH and LDH activity by regulating the phosphorylation status of PDHA1 and LDHA. We found that BHLHE40 enhanced AMPKα phosphorylation by directly suppressing the transcription of an AMPKα-specific phosphatase, PPM1F. Our immunohistochemical study showed that the expression of BHLHE40, PPM1F, and phosphorylated AMPKα correlated with the prognosis of endometrial cancer patients. Because AMPK is a central regulator of energy metabolism in cancer cells, targeting the BHLHE40‒PPM1F‒AMPK axis may represent a strategy to control cancer development.

EIF5A2 specifically regulates the transcription of aging-related genes in human neuroblastoma cells

BACKGROUND

Post-transcriptional regulation plays a critical role in controlling biological processes such as aging. Previous studies have shown that eukaryotic initiation factor 5A (EIF5A) might play a crucial role in aging. It is unknown whether EIF5A2, a second isoform of EIF5A, could impact aging through post-transcriptional regulation.

METHODS

In the present study, EIF5A2 overexpression (EIF5A2-OE) was induced in SH-SY5Y cells. RNA-seq, bioinformatics analysis and RT-qPCR validation experiments were then performed to explore the molecular mechanism of EIF5A2-mediated transcriptional regulation. Cell viability, proportion of senescent cells and the cell cycle were respectively determined by Cell Counting Kit-8, SA-β‑galactosidase and flow cytometry to evaluate the cell senescence.

RESULTS

A total of 190 downregulated and 126 upregulated genes related to EIF5A2-OE were identified. Genes closely related to cellular aging processes such as unfolded protein response (UPR), cell adhesion and calcium signaling pathway were under global transcriptional regulation. Moreover, EIF5A2-OE promoted the viability of SH-SY5Y cells and reduced cell senescence in vitro. Among 30 genes with the most significant expression differences in EIF5A2-OE cells, we identified eight genes, including ASNS, ATF3, ATF4, CEBPB, DDIT3, HERPUD1, HSPA5 and XBP1, enriched in the UPR. Through EIF5A2-tanscription factors (TFs)-targets regulation network in EIF5A2-OE cells, we found three TFs, BHLHE40, RHOXF1 and TBX20, that targeted at these eight UPR-related genes. Verification test via the published database of human glial cell tissue showed only BHLHE40 and RHOXF1 were significantly associated with EIF5A2.

CONCLUSIONS

Our findings suggest that EIF5A2 may alleviate cell senescence in vitro and mediate UPR-related genes via specific TFs. Thus, EIF5A2 could function as a regulator of aging via the regulation of transcription, which greatly expands the current understanding of the mechanisms of EIF5A2-mediated gene regulation.

Differentiated Embryo-Chondrocyte Expressed Gene1 and Parkinson's Disease: New Insights and Therapeutic Perspectives

Differentiated embryo-chondrocyte expressed gene1 (DEC1), an important transcription factor with a basic helix-loop-helix domain, is ubiquitously expressed in both human embryonic and adult tissues. DEC1 is involved in neural differentiation and neural maturation in the central nervous system (CNS). Recent studies suggest that DEC1 protects against Parkinson's disease (PD) by regulating apoptosis, oxidative stress, lipid metabolism, immune system, and glucose metabolism disorders. In this review, we summarize the recent progress on the role of DEC1 in the pathogenesis of PD and provide new insights into the prevention and treatment of PD and neurodegenerative diseases.

Prostate gland as a target organ of thyroid hormones: advances and controversies

Thyroid hormones (THs) are involved in the development and function of the male reproductive system, but their effects on the prostate have been poorly studied. This work reviews studies related to the interrelationship between the thyroid and the prostate. The information presented here is based upon bibliographic searches in PubMed using the following search terms: prostate combined with thyroid hormone or triiodothyronine, thyroxine, hypothyroidism, hyperthyroidism, or deiodinase. We identified and searched 49 articles directly related to the issue, and discarded studies related to endocrine disruptors. The number of publications has grown in the last 20 years, considering that one of the first studies was published in 1965. This review provides information based on in vitro studies, murine models, and clinical protocols in patients with thyroid disorders. Studies indicate that THs regulate different aspects of growth, metabolism, and prostate pathology, whose global effect depends on total and/or free concentrations of THs in serum, local bioavailability, and the endocrine androgen/thyronine context.

17β-Estradiol Inhibits Proliferation and Oxidative Stress in Vascular Smooth Muscle Cells by Upregulating BHLHE40 Expression

Background: Intimal hyperplasia is a major complication of restenosis after angioplasty. The abnormal proliferation and oxidative stress of vascular smooth muscle cells (VSMCs) are the basic pathological feature of neointimal hyperplasia. 17β-Estradiol can inhibit VSMCs proliferation and inflammation. However, it is still unclear whether and how 17β-Estradiol affects intimal hyperplasia.

Methods: The neointima hyperplasia was observed by hematoxylin/eosin staining. The expression of PCNA, cyclin D1, NOX1, NOX4 and p47^phox in neointima hyperplasia tissues and VSMCs was determined by qRT-PCR and Western blotting. MTS assay, cell counting and EdU staining were performed to detect cells proliferation. The oxidative stress was assessed by ROS staining.

Results: 17β-Estradiol suppressed carotid artery ligation-induced intimal hyperplasia, which is accompanied by an increase of BHLHE40 level. Furthermore, loss- and gain-of-function experiments revealed that BHLHE40 knockdown promotes, whereas BHLHE40 overexpression inhibits TNF-α-induced VSMC proliferation and oxidative stress. 17β-Estradiol inhibited TNF-α-induced VSMC proliferation and oxidative stress by promoting BHLHE40 expression, thereby suppressing MAPK signaling pathways. In addition, enforcing the expression of BHLHE40 leads to amelioration of intimal hyperplasia.

Conclusions: Our study demonstrates that 17β-Estradiol inhibits proliferation and oxidative stress in vivo and in vitro by promotion of BHLHE40 expression.

Mechanisms of Androgen Receptor Agonist- and Antagonist-Mediated Cellular Senescence in Prostate Cancer

The androgen receptor (AR) plays a leading role in the control of prostate cancer (PCa) growth. Interestingly, structurally different AR antagonists with distinct mechanisms of antagonism induce cell senescence, a mechanism that inhibits cell cycle progression, and thus seems to be a key cellular response for the treatment of PCa. Surprisingly, while physiological levels of androgens promote growth, supraphysiological androgen levels (SAL) inhibit PCa growth in an AR-dependent manner by inducing cell senescence in cancer cells. Thus, oppositional acting ligands, AR antagonists, and agonists are able to induce cellular senescence in PCa cells, as shown in cell culture model as well as ex vivo in patient tumor samples. This suggests a dual AR-signaling dependent on androgen levels that leads to the paradox of the rational to keep the AR constantly inactivated in order to treat PCa. These observations however opened the option to treat PCa patients with AR antagonists and/or with androgens at supraphysiological levels. The latter is currently used in clinical trials in so-called bipolar androgen therapy (BAT). Notably, cellular senescence is induced by AR antagonists or agonist in both androgen-dependent and castration-resistant PCa (CRPC). Pathway analysis suggests a crosstalk between AR and the non-receptor tyrosine kinase Src-Akt/PKB and the PI3K-mTOR-autophagy signaling in mediating AR-induced cellular senescence in PCa. In this review, we summarize the current knowledge of therapeutic induction and intracellular pathways of AR-mediated cellular senescence.