SUMO3 modification by PIAS1 modulates androgen receptor cellular distribution and stability

Androgen receptor cofactors: A potential role in understanding prostate cancer

Prostate cancer (PCa) is witnessing a concerning rise in incidence annually, with the androgen receptor (AR) emerging as a pivotal contributor to its growth and progression. Mounting evidence underscores the AR's ability to recruit cofactors, influencing downstream gene transcription and thereby fueling the proliferation and metastasis of PCa cells. Although, clinical strategies involving AR antagonists provide some relief, managing castration resistant prostate cancer (CRPC) remains a formidable challenge. Thus, the need of the hour lies in unearthing new drugs or therapeutic targets to effectively combat PCa. This review encapsulates the pivotal roles played by coactivators and corepressors of AR, notably androgen receptor-associated protein (ARA) and steroid receptor Coactivators (SRC) in PCa. Our data unveils how these cofactors intricately modulate histone modifications, cell cycling, SUMOylation, and apoptosis through their interactions with AR. Among the array of cofactors scrutinised, such as ARA70β, ARA24, ARA160, ARA55, ARA54, PIAS1, PIAS3, SRC1, SRC2, SRC3, PCAF, p300/CBP, MED1, and CARM1, several exhibit upregulation in PCa. Conversely, other cofactors like ARA70α, PIASy, and NCoR/SMRT demonstrate downregulation. This duality underscores the complexity of AR cofactor dynamics in PCa. Based on our findings, we propose that manipulating cofactor regulation to modulate AR function holds promise as a novel therapeutic avenue against advanced PCa. This paradigm shift offers renewed hope in the quest for effective treatments in the face of CRPC's formidable challenges.

Regulating Androgen Receptor Function in Prostate Cancer: Exploring the Diversity of Post-Translational Modifications

Androgen receptor (AR) transcriptional activity significantly influences prostate cancer (PCa) progression. In addition to ligand stimulation, AR transcriptional activity is also influenced by a variety of post-translational modifications (PTMs). A number of oncogenes and tumor suppressors have been observed leveraging PTMs to influence AR activity. Subjectively targeting these post-translational modifiers based on their impact on PCa cell proliferation is a rapidly developing area of research. This review elucidates the modifiers, contextualizes the effects of these PTMs on AR activity, and connects these cellular interactions to the progression of PCa.

The SUMOylation and ubiquitination crosstalk in cancer

BACKGROUND

The cancer occurrence and progression are largely affected by the post-translational modifications (PTMs) of proteins. Currently, it has been shown that the relationship between ubiquitination and SUMOylation is highly complex and interactive. SUMOylation affects the process of ubiquitination and degradation of substrates. Contrarily, SUMOylation-related proteins are also regulated by the ubiquitination process thus altering their protein levels or activity. Emerging evidence suggests that the abnormal regulation between this crosstalk may lead to tumorigenesis.

PURPOSE

In this review, we have discussed the study of the relationship between ubiquitination and SUMOylation, as well as the possibility of a corresponding application in tumor therapy.

METHODS

The relevant literatures from PubMed have been reviewed for this article.

CONCLUSION

The interaction between ubiquitination and SUMOylation is crucial for the occurrence and development of cancer. A greater understanding of the crosstalk of SUMOylation and ubiquitination may be more conducive to the development of more selective and effective SUMOylation inhibitors, as well as a promotion of synergy with other tumor treatment strategies.

Artepillin C overcomes apalutamide resistance through blocking androgen signaling in prostate cancer cells

Prostate cancer has a relatively good prognosis, but most cases develop resistance to hormone therapy, leading to castration-resistant prostate cancer (CRPC). Androgen receptor (AR) antagonists and a cytochrome P450 17A1 inhibitor have been used to treat CRPC, but cancer cells readily develop resistance to these drugs. In this study, to improve the therapy of CRPC, we searched for natural compounds which block androgen signaling. Among cinnamic acid derivatives contained in Brazilian green propolis, artepillin C (ArtC) suppressed expressions of androgen-induced prostate-specific antigen and transmembrane protease serine 2 in a dose-dependent manner. Reporter assays revealed that ArtC displayed AR antagonist activity, albeit weaker than an AR antagonist flutamide. In general, aberrant activation of the androgen signaling is involved in the resistance of prostate cancer cells to hormone therapy. Recently, apalutamide, a novel AR antagonist, has been in clinical use, but its drug-resistant cases have been already reported. To search for compounds which overcome the resistance to apalutamide, we established apalutamide-resistant prostate cancer 22Rv1 cells (22Rv1/APA). The 22Rv1/APA cells showed higher AR expression and androgen sensitivity than parental 22Rv1 cells. ArtC inhibited androgen-induced proliferation of 22Rv1/APA cells by suppressing the enhanced androgen signaling through blocking the nuclear translocation of AR. In addition, ArtC potently sensitized the resistant cells to apalutamide by inducing apoptotic cell death due to mitochondrial dysfunction. These results suggest that the intake of Brazilian green propolis containing ArtC improves prostate cancer therapy.

Relationship among genetic variants, obesity traits and asthma in the Taiwan Biobank

BACKGROUND AND OBJECTIVE

Obesity and asthma impose a heavy health and economic burden on millions of people around the world. The complex interaction between genetic traits and phenotypes caused the mechanism between obesity and asthma is still vague. This study investigates the relationship among obesity-related polygenic risk score (PRS), obesity phenotypes and the risk of having asthma.

METHODS

This is a matched case-control study, with 4 controls (8288 non-asthmatic) for each case (2072 asthmatic). Data were obtained from the 2008-2015 Taiwan Biobank Database and linked to the 2000-2016 National Health Insurance Research Database. All participants were ≥30 years old with no history of cancer and had a complete questionnaire, as well as physical examination, genome-wide single nucleotide polymorphisms and clinical diagnosis data. Environmental exposure, PM_2.5, was also considered. Multivariate adjusted ORs and 95% CIs were calculated using conditional logistic regression stratified by age and sex. Mediation analysis was also assessed, using a generalised linear model.

RESULTS

We found that the obese phenotype was associated with significantly increased odds of asthma by approximately 26%. Four obesity-related PRS, including body mass index (OR=1.07 (1.01-1.13)), waist circumference (OR=1.10 (1.04-1.17)), central obesity as defined by waist-to-height ratio (OR=1.09 (1.03-1.15)) and general-central obesity (OR=1.06 (1.00-1.12)), were associated with increased odds of asthma. Additional independent risk factors for asthma included lower educational level, family history of asthma, certain chronic diseases and increased PM_2.5 exposure. Obesity-related PRS is an indirect risk factor for asthma, the link being fully mediated by the trait of obesity.

CONCLUSIONS

Obese phenotypes and obesity-related PRS are independent risk factors for having asthma in adults in the Taiwan Biobank. Overall, genetic risk for obesity increases the risk of asthma by affecting the obese phenotype.

Cancer-Associated Dysregulation of Sumo Regulators: Proteases and Ligases

SUMOylation is a post-translational modification that has emerged in recent decades as a mechanism involved in controlling diverse physiological processes and that is essential in vertebrates. The SUMO pathway is regulated by several enzymes, proteases and ligases being the main actors involved in the control of sumoylation of specific targets. Dysregulation of the expression, localization and function of these enzymes produces physiological changes that can lead to the appearance of different types of cancer, depending on the enzymes and target proteins involved. Among the most studied proteases and ligases, those of the SENP and PIAS families stand out, respectively. While the proteases involved in this pathway have specific SUMO activity, the ligases may have additional functions unrelated to sumoylation, which makes it more difficult to study their SUMO-associated role in cancer process. In this review we update the knowledge and advances in relation to the impact of dysregulation of SUMO proteases and ligases in cancer initiation and progression.

Identification of ELK1 interacting peptide segments in the androgen receptor

Prostate cancer (PCa) growth requires tethering of the androgen receptor (AR) to chromatin by the ETS domain transcription factor ELK1 to coactivate critical cell proliferation genes. Disruption of the ELK1-AR complex is a validated potential means of therapeutic intervention in PCa. AR associates with ELK1 by co-opting its two ERK docking sites, through the amino-terminal domain (A/B domain) of AR. Using a mammalian two-hybrid assay, we have now functionally mapped amino acids within the peptide segments 358-457 and 514-557 in the A/B domain as required for association with ELK1. The mapping data was validated by GST (glutathione S-transferase)-pulldown and BRET (bioluminescence resonance energy transfer) assays. Comparison of the relative contributions of the interacting motifs/segments in ELK1 and AR to coactivation of ELK1 by AR suggested a parallel mode of binding of AR and ELK1 polypeptides. Growth of PCa cells was partially inhibited by deletion of the upstream segment in AR and nearly fully inhibited by deletion of the downstream segment. Our studies have identified two peptide segments in AR that mediate functional association of AR with its two docking sites in ELK1. Identification of the ELK1 recognition sites in AR should enable further structural studies of the ELK1-AR interaction and rational design of small molecule drugs to disrupt this interaction.

The Role of SUMO E3 Ligases in Signaling Pathway of Cancer Cells

Small ubiquitin-like modifier (SUMO)ylation is a reversible post-translational modification that plays a crucial role in numerous aspects of cell physiology, including cell cycle regulation, DNA damage repair, and protein trafficking and turnover, which are of importance for cell homeostasis. Mechanistically, SUMOylation is a sequential multi-enzymatic process where SUMO E3 ligases recruit substrates and accelerate the transfer of SUMO onto targets, modulating their interactions, localization, activity, or stability. Accumulating evidence highlights the critical role of dysregulated SUMO E3 ligases in processes associated with the occurrence and development of cancers. In the present review, we summarize the SUMO E3 ligases, in particular, the novel ones recently identified, and discuss their regulatory roles in cancer pathogenesis.

RNF166 plays a dual role for Lys63-linked ubiquitination and sumoylation of its target proteins

Ubiquitination and sumoylation are two important posttranslational modifications in cells. RING (Really Interesting New Gene)-type E3 ligases play essential roles in regulating a plethora of biological processes such as cell survival and death. In our previous study, we performed a microarray using inputs from MN9D dopaminergic neuronal cells treated with 6-hydroxydopamine and identified a novel RING-type E3 ligase, RNF166. We showed that RNF166 exerts proapoptotic effects via ubiquitin-dependent degradation of X-linked inhibitor of apoptosis and subsequent overactivation of caspase-dependent neuronal death following 6-hydroxydopamine treatment. In the present study, we further expanded the list of RNF166's binding substrates using mass spectral analyses of immunoprecipitates obtained from RNF166-overexpressing HEK293 cells. Poly (ADP-ribose) polymerase 1, ATPase WRNIP1, X-ray repair cross-complementing protein 5 (Ku80), and replication protein A 70 were identified as potential binding partners of RNF166. Additionally, we confirmed that RNF166 interacts with and forms lysine 63-linked polyubiquitin chains in Ku80. Consequently, these events promoted the increased stability of Ku80. Intriguingly, we found that RNF166 also contains distinct consensus sequences termed SUMO-interacting motifs and interacts with apoptosis signal-regulating kinase 1 (ASK1). We determined that RNF166 induces the sumoylation of ASK1. Overall, our data provide novel evidence that RNF166 has a dual function of Lys63-linked ubiquitination and sumoylation of its cellular targets.

Trisomy of Human Chromosome 21 Orthologs Mapping to Mouse Chromosome 10 Cause Age and Sex-Specific Learning Differences: Relevance to Down Syndrome

Down syndrome (DS), trisomy of human chromosome 21 (Hsa21), is the most common genetic cause of intellectual disability. The Dp10(1)Yey (Dp10) is a mouse model of DS that is trisomic for orthologs of 25% of the Hsa21 protein-coding genes, the entirety of the Hsa21 syntenic region on mouse chromosome 10. Trisomic genes include several involved in brain development and function, two that modify and regulate the activities of sex hormones, and two that produce sex-specific phenotypes as null mutants. These last four are the only Hsa21 genes with known sexually dimorphic properties. Relatively little is known about the potential contributions to the DS phenotype of segmental trisomy of Mmu10 orthologs. Here, we have tested separate cohorts of female and male Dp10 mice, at 3 and 9 months of age, in an open field elevated zero maze, rotarod, and balance beam, plus the learning and memory tasks, spontaneous alternation, puzzle box, double-H maze, context fear conditioning, and acoustic startle/prepulse inhibition, that depend upon the function of the prefrontal cortex, striatum, hippocampus, and cerebellum. We show that there are age and sex-specific differences in strengths and weaknesses, suggesting that genes within the telomere proximal region of Hsa21 influence the DS phenotype.

Context Fear Conditioning in Down Syndrome Mouse Models: Effects of Trisomic Gene Content, Age, Sex and Genetic Background

Down syndrome (DS), trisomy of the long arm of human chromosome 21 (Hsa21), is the most common genetic cause of intellectual disability (ID). Currently, there are no effective pharmacotherapies. The success of clinical trials to improve cognition depends in part on the design of preclinical evaluations in mouse models. To broaden understanding of the common limitations of experiments in learning and memory, we report performance in context fear conditioning (CFC) in three mouse models of DS, the Dp(16)1Yey, Dp(17)1Yey and Dp(10)1Yey (abbreviated Dp16, Dp17 and Dp10), separately trisomic for the human Hsa21 orthologs mapping to mouse chromosomes 16, 17 and 10, respectively. We examined female and male mice of the three lines on the standard C57BL/6J background at 3 months of age and Dp17 and Dp10 at 18 months of age. We also examined female and male mice of Dp17 and Dp10 at 3 months of age as F1 hybrids obtained from a cross with the DBA/2J background. Results indicate that genotype, sex, age and genetic background affect CFC performance. These data support the need to use both female and male mice, trisomy of sets of all Hsa21 orthologs, and additional ages and genetic backgrounds to improve the reliability of preclinical evaluations of drugs for ID in DS.

Dissecting multiple roles of SUMOylation in prostate cancer

Protein modification with small ubiquitin-like modifiers (SUMOs) plays dual roles in prostate cancer (PCa) tumorigenesis and development. Any intermediary of the SUMO conjugation cycle going awry may forfeit the balance between tumorigenic potential and anticancer effects. Deregulated SUMOylation on the androgen receptor and oncoproteins also takes part in this pathological process, as exemplified by STAT3/NF-κB and tumor suppressors such as PTEN and p53. Here, we outline recent developments and discoveries of SUMOylation in PCa and present an overview of its multiple roles in PCa tumorigenesis/promotion and suppression, while elucidating its potential as a therapeutic target for PCa.

PIAS1 potentiates the anti-EBV activity of SAMHD1 through SUMOylation

BACKGROUND

Sterile alpha motif and HD domain 1 (SAMHD1) is a deoxynucleotide triphosphohydrolase (dNTPase) that restricts the infection of a variety of RNA and DNA viruses, including herpesviruses. The anti-viral function of SAMHD1 is associated with its dNTPase activity, which is regulated by several post-translational modifications, including phosphorylation, acetylation and ubiquitination. Our recent studies also demonstrated that the E3 SUMO ligase PIAS1 functions as an Epstein-Barr virus (EBV) restriction factor. However, whether SAMHD1 is regulated by PIAS1 to restrict EBV replication remains unknown.

RESULTS

In this study, we showed that PIAS1 interacts with SAMHD1 and promotes its SUMOylation. We identified three lysine residues (K469, K595 and K622) located on the surface of SAMHD1 as the major SUMOylation sites. We demonstrated that phosphorylated SAMHD1 can be SUMOylated by PIAS1 and SUMOylated SAMHD1 can also be phosphorylated by viral protein kinases. We showed that SUMOylation-deficient SAMHD1 loses its anti-EBV activity. Furthermore, we demonstrated that SAMHD1 is associated with EBV genome in a PIAS1-dependent manner.

CONCLUSION

Our study reveals that PIAS1 synergizes with SAMHD1 to inhibit EBV lytic replication through protein-protein interaction and SUMOylation.

Post-Translational Modifications That Drive Prostate Cancer Progression

While a protein primary structure is determined by genetic code, its specific functional form is mostly achieved in a dynamic interplay that includes actions of many enzymes involved in post-translational modifications. This versatile repertoire is widely used by cells to direct their response to external stimuli, regulate transcription and protein localization and to keep proteostasis. Herein, post-translational modifications with evident potency to drive prostate cancer are explored. A comprehensive list of proteome-wide and single protein post-translational modifications and their involvement in phenotypic outcomes is presented. Specifically, the data on phosphorylation, glycosylation, ubiquitination, SUMOylation, acetylation, and lipidation in prostate cancer and the enzymes involved are collected. This type of knowledge is especially valuable in cases when cancer cells do not differ in the expression or mutational status of a protein, but its differential activity is regulated on the level of post-translational modifications. Since their driving roles in prostate cancer, post-translational modifications are widely studied in attempts to advance prostate cancer treatment. Current strategies that exploit the potential of post-translational modifications in prostate cancer therapy are presented.