LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK-A11

Anticancer properties of histone deacetylase inhibitors - what is their potential?

INTRODUCTION

Histone modifications are crucial epigenetic mechanisms for regulating gene expression. Histone acetyltransferases and deacetylases (HDACs) catalyze histone acetylation, a process that mediates transcription. Over recent decades, studies have demonstrated that targeting histone acetylation can be effective in cancer treatment, leading to the development and approval of several HDAC inhibitors.

AREAS COVERED

A comprehensive literature review was conducted using the PubMed database to identify studies evaluating the anticancer efficacy of approved and novel HDAC inhibitors.

EXPERT OPINION

Accumulating evidence highlights the promising benefits of combining HDAC inhibitors with other anticancer agents. Additionally, HDAC-targeting therapeutics could enhance the sensitivity of cancer cells to chemotherapeutics or targeted tyrosine kinase inhibitors, thereby improving overall treatment outcomes. Future clinical studies must focus on optimizing combination therapies to ensure efficacy while maintaining manageable safety profiles.

The antidepressant drug sertraline is a novel inhibitor of yeast Pah1 and human lipin 1 phosphatidic acid phosphatases

Phosphatidic acid phosphatase (PAP) is an evolutionarily conserved eukaryotic enzyme that catalyzes the Mg2+-dependent dephosphorylation of phosphatidic acid to produce diacylglycerol. The product and substrate of PAP are key intermediates in the synthesis of triacylglycerol and membrane phospholipids. PAP activity is associated with lipid-based cellular defects indicating the enzyme is an important target for regulation. We identified that the antidepressant sertraline is a novel inhibitor of PAP. Using Saccharomyces cerevisiae Pah1 as a model PAP, sertraline inhibited the activity by a noncompetitive mechanism. Sertraline also inhibited the PAP activity of human lipin 1 (α, β, and γ), an orthologue of Pah1. The inhibitor constants of sertraline for the S. cerevisiae and human PAP enzymes were 7-fold and ∼2-fold, respectively, lower than those of propranolol, a commonly used PAP inhibitor. Consistent with the inhibitory mechanism of sertraline and propranolol, molecular docking of the inhibitors predicts that they interact with non-catalytic residues in the haloacid dehalogenase-like catalytic domain of Pah1. The Pah1-CC (catalytic core) variant, which lacks regulatory sequences, was inhibited by both drugs in accordance with molecular docking data. That Pah1 is a physiological target of sertraline in S. cerevisiae is supported by the observations that the overexpression of PAH1 rescued the sertraline-mediated inhibition of pah1Δ mutant cell growth, the lethal effect of overexpressing Pah1-CC was rescued by sertraline supplementation, and that a sublethal dose of the drug resulted in a 2-fold decrease in TAG content.

Ferroptosis-Related Gene Signature for Prognosis Prediction in Acute Myeloid Leukemia and Potential Therapeutic Options

Background

Limited data were available to understand the significance of ferroptosis in leukemia prognosis, regardless of the genomic background.

Methods

RNA-seq data from 151 AML patients were analyzed from The Cancer Genome Atlas (TCGA) database, along with 70 healthy samples from the Genotype-Tissue Expression (GTEx) database. Ferroptosis-related genes (FRGs) features were constructed by multivariate COX regression analysis and risk scores were calculated for each sample and a novel prediction model was identified. The validation was carried out using data from 35 AML patients and 13 healthy controls in our cohort. Drug sensitivity analysis was conducted on various chemotherapeutic drugs.

Results

A signature of 10 FRGs was identified, as prognostic predictors for AML, and the risk scores were calculated to constructed the prognostic features of FRGs. Significantly lower overall survival was observed in the high-risk group. The predictive ability of these features for AML prognosis was confirmed using Cox regression analysis, ROC curves, and DCA. The prediction model performed well in our clinical practices, and had its potential superiority when comparing to classical NCCN risk stratification. Multiple chemotherapy drugs, including paclitaxel, dactinomycin, cisplatin, etc. had a lower IC50 in FRGs high-risk group than low-risk group.

Conclusion

The AML prognosis model based on FRGs accurately predicts AML prognosis and drug sensitivity, and the drugs identified worthy further investigation.

Lipin-1, a Versatile Regulator of Lipid Homeostasis, Is a Potential Target for Fighting Cancer

The rewiring of lipid metabolism is a major adaptation observed in cancer, and it is generally associated with the increased aggressiveness of cancer cells. Targeting lipid metabolism is therefore an appealing therapeutic strategy, but it requires a better understanding of the specific roles played by the main enzymes involved in lipid biosynthesis. Lipin-1 is a central regulator of lipid homeostasis, acting either as an enzyme or as a co-regulator of transcription. In spite of its important functions it is only recently that several groups have highlighted its role in cancer. Here, we will review the most recent research describing the role of lipin-1 in tumor progression when expressed by cancer cells or cells of the tumor microenvironment. The interest of its inhibition as an adjuvant therapy to amplify the effects of anti-cancer therapies will be also illustrated.

LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK-A11

Phosphatidylinositol-3 kinase (PI3K) inhibitor and histone deacetylase (HDAC) inhibitor have been developed as potential anticancer drugs. However, the cytotoxicity of PI3K inhibitor or HDAC inhibitor alone is relatively weak. We recently developed a novel HDAC/PI3K dual inhibitor FK-A11 and confirmed its enhanced cytotoxicity when compared to that of PI3K inhibitor or HDAC inhibitor alone on several cancer cell lines. However, the in vivo antitumor activity of FK-A11 was insufficient. We conducted high-throughput RNA interfering screening and identified gene LPIN1 which enhances the cytotoxicity of FK-A11. Downregulation of LPIN1 enhanced simultaneous inhibition of HDAC and PI3K by FK-A11 and enhanced the cytotoxicity of FK-A11. Propranolol, a beta-adrenoreceptor which is also a LPIN1 inhibitor, enhanced the in vitro and in vivo cytotoxicity and antitumor effect of FK-A11. These findings should help in the development of FK-A11 as a novel HDAC/PI3K dual inhibitor.