LSD1 Promotes Prostate Cancer Cell Survival by Destabilizing FBXW7 at Post-Translational Level

Unveiling New Binding Sites and Allosteric Regulation Mechanisms of LSD1 for Novel Therapeutics

Lysine-specific demethylase 1 (LSD1) regulates key cellular processes through both demethylase-dependent and -independent functions. Current clinical LSD1 inhibitors target its demethylase functions, and issues like the inability to fully modulate LSD1's demethylase-independent functions have limited their clinical efficacy. SP2509, an allosteric LSD1 inhibitor, can affect both demethylase-dependent and -independent functions of LSD1. Understanding the allosteric regulation mechanisms of SP2509 may facilitate the development of new LSD1 inhibitors. Using SP2509 as a probe, two new binding modes are identified in this work, both of which can alter the conformation of substrate binding pocket, effectively blocking H3 substrate binding and inhibiting the demethylase activity. Interestingly, one binding mode induces significant allosteric bending of Tower/CoREST domain, disrupting the nucleosome substrate binding─an effect not previously reported. This unique binding mode is also validated through in vitro biochemical characterizations. These findings provide invaluable structural insights for designing next-generation LSD1 inhibitors for novel therapeutics.

Leveraging non-enzymatic functions of LSD1 for novel therapeutics

Lysine-specific demethylase 1 (LSD1) is a key enzyme that removes the methylation marks from lysines in the histone tails of nucleosomes. Emerging evidence suggests that LSD1 exhibits both enzyme-dependent and independent functions across various diseases. However, most LSD1-targeted therapies in clinical trials focus on its classic demethylase activity. Only one allosteric inhibitor (SP-2577) and two nonproteolysis-targeting chimera (PROTAC) LSD1 degraders (BEA-17 and UM171), which target its enzyme-independent functions, have entered clinical assessment. Given the limited exploration of therapeutic strategies targeting the non-enzymatic functions of LSD1, in this opinion, we summarize current insights into its biological roles and structural characteristics. We also highlight potential therapeutic interventions targeting the non-enzymatic functions of LSD1, including allosteric inhibitors, protein-protein interaction (PPI) inhibitors, and small-molecule degraders, and discuss challenges and future directions in drug discovery targeting these functions.

Histone demethylase LSD1 promotes castration-resistant prostate cancer by causing widespread gene expression derangements

Lysine-specific demethylase 1 (LSD1), a histone demethylase crucial for embryonic development and tissue differentiation, has an undefined role in prostate cancer (PCa), especially castration-resistant PCa. The present study represents a pioneering endeavor to comprehensively dissect the function of LSD1 within the PCa landscape. Our investigations revealed that attenuation of LSD1 expression exerts multiple inhibitory effects on PCa cells. Specifically, it curtails the proliferation and colony-forming ability of PC-3 cells, concomitantly promotes apoptosis, and impedes cell invasion. Notably, knockdown of LSD1 triggers significant perturbations in the expression profiles of pivotal proteins, such as prostate-specific antigen (PSA), forkhead box A1 (FOXA1), and NKX3.1, thereby shedding new light on the underlying molecular mechanisms governing PCa progression. Leveraging bioinformatics analysis and transcriptome sequencing, we unearthed that LSD1 knockdown precipitates widespread gene expression dysregulation, with 3166 genes exhibiting differential expression patterns, which in turn impact a broad spectrum of cellular processes. Importantly, we identified that LSD1 modulates the methylation modification of histone H3 lysine 4 monomethylation (H3K4me1) in the promoter region of matrix metallopeptidase 13 (MMP13), thereby orchestrating its expression. In both orthotopic and metastatic tumor models, as well as in vitro cell cultures, the LSD1 inhibitor GSK2879552 demonstrated potent efficacy in suppressing PCa progression. To sum up, this study not only uncovers the oncogenic role of LSD1 in PCa but also validates the therapeutic promise of GSK2879552, furnishing novel perspectives and prospective targets for the clinical management of PCa.

Anticancer Drugs of Lysine Specific Histone Demethylase-1 (LSD1) Display Variable Inhibition on Nucleosome Substrates

Lysine specific demethylase-1 (LSD1) serves as a regulator of transcription and represents a promising epigenetic target for anticancer treatment. LSD1 inhibitors are in clinical trials for the treatment of Ewing's sarcoma (EWS), acute myeloid leukemia, and small cell lung cancer, and the development of robust inhibitors requires accurate methods for probing demethylation, potency, and selectivity. Here, the inhibition kinetics on the H3K4me2 peptide and nucleosome substrates was examined, comparing the rates of demethylation in the presence of reversible [CC-90011 (PD) and SP-2577 (SD)] and irreversible [ORY-1001 (ID) and tranylcypromine (TCP)] inhibitors. Inhibitors were also subject to viability studies in three human cell lines and Western blot assays to monitor H3K4me2 nucleosome levels in EWS (TC-32) cells, enabling a correlation of drug potency, inhibition in vitro, and cell-based studies. For example, SP-2577, a drug in clinical trials for EWS, inhibits activity on small peptide substrates (Ki = 60 ± 20 nM) using an indirect coupled assay but does not inhibit demethylation on H3K4me2 peptides or nucleosomes using direct Western blot approaches. In addition, the drug has no effect on H3K4me2 levels in TC-32 cells. These data show that SP-2577 is not an LSD1 enzyme inhibitor, although the drug may function independent of demethylation due to its cytotoxic selectivity in TC-32 cells. Taken together, this work highlights the pitfalls of using coupled assays to ascribe a drug's mode of action, emphasizes the use of physiologically relevant substrates in epigenetic drug targeting strategies, and provides insight into the development of substrate-selective inhibitors of LSD1.

Transcriptional Up-Regulation of FBXW7 by KCa1.1 K+ Channel Inhibition through the Nrf2 Signaling Pathway in Human Prostate Cancer LNCaP Cell Spheroid Model

The tumor suppressor gene F-box and WD repeat domain-containing (FBXW) 7 reduces cancer stemness properties by promoting the protein degradation of pluripotent stem cell markers. We recently demonstrated the transcriptional repression of FBXW7 by the three-dimensional (3D) spheroid formation of several cancer cells. In the present study, we found that the transcriptional activity of FBXW7 was promoted by the inhibition of the Ca2+-activated K+ channel, KCa1.1, in a 3D spheroid model of human prostate cancer LNCaP cells through the Akt-Nrf2 signaling pathway. The transcriptional activity of FBXW7 was reduced by the siRNA-mediated inhibition of the CCAAT-enhancer-binding protein C/EBP δ (CEBPD) after the transfection of miR223 mimics in the LNCaP spheroid model, suggesting the transcriptional regulation of FBXW7 through the Akt-Nrf2-CEBPD-miR223 transcriptional axis in the LNCaP spheroid model. Furthermore, the KCa1.1 inhibition-induced activation of FBXW7 reduced (1) KCa1.1 activity and protein levels in the plasma membrane and (2) the protein level of the cancer stem cell (CSC) markers, c-Myc, which is a molecule degraded by FBXW7, in the LNCaP spheroid model, indicating that KCa1.1 inhibition-induced FBXW7 activation suppressed CSC conversion in KCa1.1-positive cancer cells.

KBTBD4-mediated reduction of MYC is critical for hematopoietic stem cell expansion upon UM171 treatment

ABSTRACT

Ex vivo expansion of hematopoietic stem cells (HSCs) is gaining importance for cell and gene therapy, and requires a shift from dormancy state to activation and cycling. However, abnormal or excessive HSC activation results in reduced self-renewal ability and increased propensity for myeloid-biased differentiation. We now report that activation of the E3 ligase complex CRL3KBTBD4 by UM171 not only induces epigenetic changes through CoREST1 degradation but also controls chromatin-bound master regulator of cell cycle entry and proliferative metabolism (MYC) levels to prevent excessive activation and maintain lympho-myeloid potential of expanded populations. Furthermore, reconstitution activity and multipotency of UM171-treated HSCs are specifically compromised when MYC levels are experimentally increased despite degradation of CoREST1.

LSD1 in drug discovery: From biological function to clinical application

Lysine-specific demethylase 1 (LSD1) is a flavin adenine dinucleotide (FAD) dependent monoamine oxidase (MAO) that erases the mono-, and dimethylation of histone 3 lysine 4 (H3K4), resulting in the suppression of target gene transcriptions. Besides, it can also demethylate some nonhistone substrates to regulate their biological functions. As reported, LSD1 is widely upregulated and plays a key role in several kinds of cancers, pharmacological or genetic ablation of LSD1 in cancer cells suppresses cell aggressiveness by several distinct mechanisms. Therefore, numerous LSD1 inhibitors, including covalent and noncovalent, have been developed and several of them have entered clinical trials. Herein, we systemically reviewed and discussed the biological function of LSD1 in tumors, lymphocytes as well as LSD1-targeting inhibitors in clinical trials, hoping to benefit the field of LSD1 and its inhibitors.

The role and prospect of lysine-specific demethylases in cancer chemoresistance

Histone methylation plays a key function in modulating gene expression, and preserving genome integrity and epigenetic inheritance. However, aberrations of histone methylation are commonly observed in human diseases, especially cancer. Lysine methylation mediated by histone methyltransferases can be reversed by lysine demethylases (KDMs), which remove methyl marks from histone lysine residues. Currently, drug resistance is a main impediment for cancer therapy. KDMs have been found to mediate drug tolerance of many cancers via altering the metabolic profile of cancer cells, upregulating the ratio of cancer stem cells and drug-tolerant genes, and promoting the epithelial-mesenchymal transition and metastatic ability. Moreover, different cancers show distinct oncogenic addictions for KDMs. The abnormal activation or overexpression of KDMs can alter gene expression signatures to enhance cell survival and drug resistance in cancer cells. In this review, we describe the structural features and functions of KDMs, the KDMs preferences of different cancers, and the mechanisms of drug resistance resulting from KDMs. We then survey KDM inhibitors that have been used for combating drug resistance in cancer, and discuss the opportunities and challenges of KDMs as therapeutic targets for cancer drug resistance.

JARID2 and EZH2, The Eminent Epigenetic Drivers In Human Cancer

Cancer has become a prominent cause of death, accounting for approximately 10 million death worldwide as per the World Health Organization reports 2020. Epigenetics deal with the alterations of heritable phenotypes, except for DNA alterations. Currently, we are trying to comprehend the role of utmost significant epigenetic genes involved in the burgeoning of human cancer. A sundry of studies reported the Enhancer of Zeste Homologue2 (EZH2) as a prime catalytic subunit of Polycomb Repressive Complex2, which is involved in several pivotal activities, including embryogenesis. In addition, EZH2 has detrimental effects leading to the onset and metastasis of several cancers. Jumonji AT Rich Interacting Domain2 (JARID2), an undebated crucial nuclear factor, has strong coordination with the PRC2 family. In this review, we discuss various epigenetic entities, primarily focusing on the possible role and mechanism of EZH2 and the significant contribution of JARID2 in human cancers.

LSD1 for the Targeted Regulation of Adipose Tissue

White and thermal (brown and beige) adipose tissue energy storage and oxidative regulation pathways play a central role in maintaining the energy balance throughout the body, and the dysregulation of these pathways is closely related to glucose and lipid metabolism disorders and adipose tissue dysfunction, including obesity, chronic inflammation, insulin resistance, mitochondrial dysfunction, and fibrosis. Recent epigenetic studies have identified the novel regulatory element LSD1, which controls the above parameters, and have provided new mechanistic possibilities for re-encoding the fate and function of adipocytes. In this review, we outline the current advances in adipocyte metabolism in physiology and disease and discuss possible strategies for LSD1 to alter the phenotype of adipose tissue and thus influence energy utilization to improve metabolic health.

Energy-Stress-Mediated AMPK Activation Promotes GPX4-Dependent Ferroptosis through the JAK2/STAT3/P53 Axis in Renal Cancer

Energy stress is an unfavorable condition that tumor cells are often exposed to. Ferroptosis is considered an emerging target for tumor therapy. However, the role of ferroptosis in energy stress in renal cancer is currently unknown. In this study, we found that glucose deprivation significantly enhanced GPX4-dependent ferroptosis through AMPK activation. Further, AMPK activation suppressed GPX4 expression at the transcriptional level through the upregulation of P53 expression. Additionally, the inactivation of JAK2/STAT3 transcriptionally promoted P53 expression, thereby promoting AMPK-mediated GPX4-dependent ferroptosis. In conclusion, energy stress promotes AMPK-mediated GPX4-dependent erastin-induced ferroptosis in renal cancer through the JAK2/STAT3/P53 signaling axis.

Long non-coding RNAs affecting cell metabolism in cancer

Metabolic reprogramming is commonly recognized as one important hallmark of cancers. Cancer cells present significant alteration of glucose metabolism, oxidative phosphorylation, and lipid metabolism. Recent findings demonstrated that long non-coding RNAs control cancer development and progression by modulating cell metabolism. Here, we give an overview of breast cancer metabolic reprogramming and the role of long non-coding RNAs in driving cancer-specific metabolic alteration.

Mechanisms of carcinogenic activity triggered by lysine-specific demethylase 1A

Epigenetics has emerged as a prime focus area in the field of cancer research. Lysine-specific demethylase 1A (LSD1), the first discovered histone demethylase, is mainly responsible for catalysing demethylation of histone 3 lysine 4 (H3K4) and H3K9 to activate or inhibit gene transcription. LSD1 is abnormally expressed in various cancers and participates in cancer proliferation, apoptosis, metastasis, invasion, drug resistance and other processes by interacting with regulatory factors. Therefore, it may serve as a potential therapeutic target for cancer. This review summarises the major oncogenic mechanisms mediated by LSD1 and provides a reference for developing novel and efficient anticancer strategies targeting LSD1.

Therapeutic targets and signaling pathways of active components of QiLing decoction against castration-resistant prostate cancer based on network pharmacology

QiLing decoction (QLD) is a traditional Chinese medicine compound. This study aims to explore the therapeutic effect of QLD in castration-resistant prostate cancer (CRPC) and its potential bio-targets. A total of 51 active components and QLD 149 targets were identified using bioinformatics analysis. Additionally, five optimal hub target genes were screened including tumor protein P53 (TP53), interleukin-6 (IL-6), vascular endothelial growth factor-A (VEGF-A), caspase-3 (CASP-3), and estrogen receptor-1 (ESR-1). The interrelated network between active components of QLD and their potential targets was constructed. The molecular function, biological processes, and signaling pathways of QLD-against CRPC were identified. Moreover, QLD was found to efficiently exert a repressive effect on CRPC tumor growth mainly by suppressing the activation of HIF-α/VEGFA and TNF-α/IL6 signaling pathways, and increasing the P53 expression level. These results successfully indicated the potential anti-CRPC mechanism of the active components of QLD.

Comprehensive in Vitro Characterization of the LSD1 Small Molecule Inhibitor Class in Oncology

Lysine-specific demethylase 1 (LSD1 or KDM1A) is a chromatin modifying enzyme playing a key role in the cell cycle and cell differentiation and proliferation through the demethylation of histones and nonhistone substrates. In addition to its enzymatic activity, LSD1 plays a fundamental scaffolding role as part of transcription silencing complexes such as rest co-repressor (CoREST) and nucleosome remodeling and deacetylase (NuRD). A host of classical amine oxidase inhibitors such as tranylcypromine, pargyline, and phenelzine together with LSD1 tool compounds such as SP-2509 and GSK-LSD1 have been extensively utilized in LSD1 mechanistic cancer studies. Additionally, several optimized new chemical entities have reached clinical trials in oncology such as ORY-1001 (iadademstat), GSK2879552, SP-2577 (seclidemstat), IMG-7289 (bomedemstat), INCB059872, and CC-90011 (pulrodemstat). Despite this, no single study exists that characterizes them all under the same experimental conditions, preventing a clear interpretation of published results. Herein, we characterize the whole LSD1 small molecule compound class as inhibitors of LSD1 catalytic activity, disruptors of SNAIL/GFI1 (SNAG)-scaffolding protein-protein interactions, inducers of cell differentiation, and potential anticancer treatments for hematological and solid tumors to yield an updated, unified perspective of this field. Our results highlight significant differences in potency and selectivity among the clinical compounds with iadademstat being the most potent and reveal that most of the tool compounds have very low activity and selectivity, suggesting some conclusions derived from their use should be taken with caution.

Shooting at Moving and Hidden Targets-Tumour Cell Plasticity and the Notch Signalling Pathway in Head and Neck Squamous Cell Carcinomas

Head and Neck Squamous Cell Carcinoma (HNSCC) is often aggressive, with poor response to current therapies in approximately 40-50% of the patients. Current therapies are restricted to operation and irradiation, often combined with a small number of standard-of-care chemotherapeutic drugs, preferentially for advanced tumour patients. Only very recently, newer targeted therapies have entered the clinics, including Cetuximab, which targets the EGF receptor (EGFR), and several immune checkpoint inhibitors targeting the immune receptor PD-1 and its ligand PD-L1. HNSCC tumour tissues are characterized by a high degree of intra-tumour heterogeneity (ITH), and non-genetic alterations that may affect both non-transformed cells, such as cancer-associated fibroblasts (CAFs), and transformed carcinoma cells. This very high degree of heterogeneity likely contributes to acquired drug resistance, tumour dormancy, relapse, and distant or lymph node metastasis. ITH, in turn, is likely promoted by pronounced tumour cell plasticity, which manifests in highly dynamic and reversible phenomena such as of partial or hybrid forms of epithelial-to-mesenchymal transition (EMT), and enhanced tumour stemness. Stemness and tumour cell plasticity are strongly promoted by Notch signalling, which remains poorly understood especially in HNSCC. Here, we aim to elucidate how Notch signal may act both as a tumour suppressor and proto-oncogenic, probably during different stages of tumour cell initiation and progression. Notch signalling also interacts with numerous other signalling pathways, that may also have a decisive impact on tumour cell plasticity, acquired radio/chemoresistance, and metastatic progression of HNSCC. We outline the current stage of research related to Notch signalling, and how this pathway may be intricately interconnected with other, druggable targets and signalling mechanisms in HNSCC.

Lysine-specific demethylase 1 induced epithelial-mesenchymal transition and promoted renal fibrosis through Jagged-1/Notch signaling pathway

OBJECTIVE

TGF-β1-induced excessive deposition of extracellular matrix (ECM) and epithelial-mesenchymal transition (EMT) process of tubular epithelial cells play critical roles in the progression of renal fibrosis. We are aimed to explore the effects of lysine-specific demethylase 1 (LSD1) in TGF-β1-treated HK-2 cells and in rats with unilateral ureteral obstruction (UUO), and to investigate the underlying molecular mechanism.

METHODS

TGF-β1-treated HK-2 cells and UUO-treated rats were used to establish the model of renal fibrosis in vitro and in vivo, respectively. Protein expression of LSD1, E-cadherin, a-smooth muscle actin (a-SMA), Vimentin, Jagged-1, Notch-1 and Notch-2 were detected by Western blot. The concentrations of type I collagen (Col-I) and Fibronectin (FN) were measured by ELISA. Transwell assay were used to assess cell invasion.

RESULTS

LSD1 was dramatically increased in TGF-β1-stimulated HK-2 cells. Knockdown of LSD1 decreased the TGF-β1-induced secretion of Col-I and FN, and suppressed TGF-β1-induced expression of E-cadherin,α-SMA and Vimentin, while suppressed cell invasion. Consistent with the in vitro data, the severe histopathological damage, collagen deposition and reduced E-cadherin, increased α-SMA induced by UUO was abated by the knockdown of LSD1 in vivo. Moreover, knockdown of LSD1 suppressed TGF-β1-induced expression of Jagged-1, Notch-1 and Notch-2. Furthermore, we found that inhibition of Notch signaling by a γ-secretase inhibitor RO4929097 almost recapitulated the effects of LSD1 knockdown in TGF-β1-induced HK-2 cells, and at least in part reversed the effects of LSD1 overexpression on EMT and ECM deposition in HK-2 cells.

CONCLUSIONS

Taken together, LSD1 significantly impact on the progression of TGF-β1-mediated EMT and ECM deposition in HK-2 cells, and it may represent novel target for the prevention strategies of renal fibrosis.