An Update of Lysine Specific Demethylase 1 Inhibitor: A Patent Review (2016-2020)

Pulrodemstat, a selective inhibitor of KDM1A, suppresses head and neck squamous cell carcinoma growth by triggering apoptosis

BACKGROUND

Chemotherapy is often ineffective as a first-line treatment for head and neck squamous cell carcinoma (HNSCC), and a more precise and effective therapeutic option is urgently needed.

METHODS

High-throughput screening of a histone demethylase inhibitor library was performed to identify potential drugs for treating HNSCC. The Cancer Genome Atlas (TCGA) and single-cell sequencing were used to evaluate the potential diagnostic value and expression distribution of candidate drug targets. Colony formation, transwell assays, and flow cytometry analyses were used to assess the antitumor function of the potential drugs. The CCK-8 assay was used to compare the antitumor activity of the candidate drug and the traditional chemotherapy drug. Bioinformatic analysis based on TCGA database was used for unveiling the upstream signaling.

RESULTS

Pulrodemstat, a selective KDM1A inhibitor that is ongoing clinical trial, stood out as the most effective candidate anti-HNSCC drug based on the high-throughput screening. IC50 analysis revealed that Pulrodemstat might possess stronger anti-tumor activity than 5-Fu. Additionally, Pulrodemstat dramatically suppressed HNSCC cell proliferation and migration without inducing toxicity in normal cells. TCGA analysis revealed that KDM1A is positively associated with tumor proliferation, DNA repair, and DNA replication in HNSCC. Consistent with these results, Pulrodemstat substantially induced apoptosis in the HNSCC cells. Furthermore, TCGA analysis revealed that KDM1A was aberrantly overexpressed in HNSCC, positively correlated with malignancy, and negatively associated with the clinical outcomes of HNSCC patients. Notably, single-cell analysis indicated that KDM1A was mainly distributed in the malignant cells of HNSCC samples, highlighting that Pulrodemstat may be a more precise therapeutic option for HNSCC. In addition, methylation occupancies in the KDM1A promoter were substantially low in HNCC tumors, and low methylation occupancies in the KDM1A promoter predicted poor clinical outcomes in HNSCC. These data are consistent with the KDM1A expression in HNSCC. Moreover, TET3, a DNA demethylase, was strongly and positively correlated with KDM1A expression.

CONCLUSIONS

Pulrodemstat is an effective therapeutic drug for HNSCC. Thus, the TET3/KDM1A axis may account for the malignant phenotype of HNSCC.

Neddylation-dependent LSD1 destabilization inhibits the stemness and chemoresistance of gastric cancer

Histone lysine-specific demethylase 1 (LSD1) expression has been evaluated in multiple tumors, including gastric cancer (GC). However, the mechanisms underlying LSD1 dysregulation in GC remain largely unclear. In this study, neural precursor cell-expressed developmentally down-regulated protein 8 (NEDD8) was identified to be conjugated to LSD1 at K63 by ubiquitin-conjugating enzyme E2 M (UBE2M), and this neddylated LSD1 could promote LSD1 ubiquitination and degradation, leading to a decrease of GC cell stemness and chemoresistance. Herein, our findings revealed a novel mechanism of LSD1 neddylation and its contribution to decreasing GC cell stemness and chemoresistance. Taken together, our findings may whistle about the future application of neddylation inhibitors.

Phenothiazine-Based LSD1 Inhibitor Promotes T-Cell Killing Response of Gastric Cancer Cells

Histone lysine specific demethylase 1 (LSD1) has been recognized as an important epigenetic target for cancer treatment. Although several LSD1 inhibitors have entered clinical trials, the discovery of novel potent LSD1 inhibitors remains a challenge. In this study, the antipsychotic drug chlorpromazine was characterized as an LSD1 inhibitor (IC50 = 5.135 μM), and a series of chlorpromazine derivatives were synthesized. Among them, compound 3s (IC50 = 0.247 μM) was the most potent one. More importantly, compound 3s inhibited LSD1 in the cellular level and downregulated the expression of programmed cell death-ligand 1 (PD-L1) in BGC-823 and MFC cells to enhance T-cell killing response. An in vivo study confirmed that compound 3s can inhibit MFC cell proliferation without significant toxicity in immunocompetent mice. Taken together, our findings indicated that the novel LSD1 inhibitor 3s tethering a phenothiazine scaffold may serve as a lead compound for further development to activate T-cell immunity in gastric cancer.

Ruta angustifolia Pers. (Narrow-Leaved Fringed Rue): Pharmacological Properties and Phytochemical Profile

The genus Ruta in the family Rutaceae includes about 40 species, such as the well-known plants R. graveolens L. (common rue) or R. chalepensis L. (fringed rue), but also much lesser-known species such as R. angustifolia Pers. (narrow-leaved fringed rue). This rue specie, originating from the Mediterranean region, is well-distributed in Southeast Asia, notably in the Indo-Chinese peninsula and other territories. In some countries, such as Malaysia, the plant is used to treat liver diseases and cancer. Extracts of R. angustifolia display antifungal, antiviral and antiparasitic effects. Diverse bioactive natural products have been isolated from the aerial parts of the plant, notably quinoline alkaloids and furocoumarins, which present noticeable anti-inflammatory, antioxidant and/or antiproliferative properties. The present review discusses the main pharmacological properties of the plant and its phytoconstituents, with a focus on the anticancer activities evidenced with diverse alkaloids and terpenoids isolated from the aerial parts of the plant. Quinoline alkaloids such as graveoline, kokusaginine, and arborinine have been characterized and their mode of action defined. Arborinine stands as a remarkable inhibitor of histone demethylase LSD1, endowed with promising anticancer activities. Other anticancer compounds, such as the furocoumarins chalepin and rutamarin, have revealed antitumor effects. Their mechanism of action is discussed together with that of other bioactive natural products, including angustifolin and moskachans. Altogether, R. angustifolia Pers. presents a rich phytochemical profile, fully consistent with the traditional use of the plant to treat cancer. This rue species, somewhat neglected, warrant further investigations as a medicinal plant and a source of inspiration for drug discovery and design.

LSD1 deletion decreases exosomal PD-L1 and restores T-cell response in gastric cancer

BACKGROUND

Histone lysine-specific demethylase 1 (LSD1) expression has been shown to be significantly elevated in gastric cancer (GC) and may be associated with the proliferation and metastasis of GC. It has been reported that LSD1 repressed tumor immunity through programmed cell death 1 ligand 1 (PD-L1) in melanoma and breast cancer. The role of LSD1 in the immune microenvironment of GC is unknown.

METHODS

Expression LSD1 and PD-L1 in GC patients was analyzed by immunohistochemical (IHC) and Western blotting. Exosomes were isolated from the culture medium of GC cells using an ultracentrifugation method and characterized by transmission electronic microscopy (TEM), nanoparticle tracking analysis (NTA), sucrose gradient centrifugation, and Western blotting. The role of exosomal PD-L1 in T-cell dysfunction was assessed by flow cytometry, T-cell killing and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Through in vivo exploration, mouse forestomach carcinoma (MFC) cells with LSD1 knockout (KO) showed significantly slow growth in 615 mice than T-cell-deficient BALB/c nude mice. Meanwhile, in GC specimens, expression of LSD1 was negatively correlated with that of CD8 and positively correlated with that of PD-L1. Further study showed that LSD1 inhibited the response of T cells in the microenvironment of GC by inducing the accumulation of PD-L1 in exosomes, while the membrane PD-L1 stayed constant in GC cells. Using exosomes as vehicles, LSD1 also obstructed T-cell response of other cancer cells while LSD1 deletion rescued T-cell function. It was found that while relying on the existence of LSD1 in donor cells, exosomes can regulate MFC cells proliferation with distinct roles depending on exosomal PD-L1-mediated T-cell immunity in vivo.

CONCLUSION

LSD1 deletion decreases exosomal PD-L1 and restores T-cell response in GC; this finding indicates a new mechanism with which LSD1 may regulate cancer immunity in GC and provides a new target for immunotherapy against GC.