Downregulation of PSAT1 inhibits cell proliferation and migration in uterine corpus endometrial carcinoma

Novel strategies to overcome chemoresistance in human glioblastoma

Temozolomide (TMZ) is currently the first-line chemotherapeutic agent for the treatment of glioblastoma multiforme (GBM). However, the inherent heterogeneity of GBM often results in suboptimal outcomes, particularly due to varying degrees of resistance to TMZ. Over the past several decades, O6-methylguanine-DNA methyltransferase (MGMT)-mediated DNA repair pathway has been extensively investigated as a target to overcome TMZ resistance. Nonetheless, the combination of small molecule covalent MGMT inhibitors with TMZ and other chemotherapeutic agents has frequently led to adverse clinical effects. Recently, additional mechanisms contributing to TMZ resistance have been identified, including epidermal growth factor receptor (EGFR) mutations, overactivation of intracellular signalling pathways, energy metabolism reprogramming or survival autophagy, and changes in tumor microenvironment (TME). These findings suggest that novel therapeutic strategies targeting these mechanisms hold promise for overcoming TMZ resistance in GBM patients. In this review, we summarize the latest advancements in understanding the mechanisms underlying intrinsic and acquired TMZ resistance. Additionally, we compile various small-molecule compounds with potential to mitigate chemoresistance in GBM. These mechanism-based compounds may enhance the sensitivity of GBM to TMZ and related chemotherapeutic agents, thereby improving overall survival rates in clinical practice.

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.

Optimizing hybrid ensemble feature selection strategies for transcriptomic biomarker discovery in complex diseases

Biomedical research takes advantage of omic data, such as transcriptomics, to unravel the complexity of diseases. A conventional strategy identifies transcriptomic biomarkers characterized by expression patterns associated with a phenotype by relying on feature selection approaches. Hybrid ensemble feature selection (HEFS) has become increasingly popular as it ensures robustness of the selected features by performing data and functional perturbations. However, it remains difficult to make the best suited choices at each step when designing such approaches. We conducted an extensive analysis of four possible HEFS scenarios for the identification of Stage IV colorectal, Stage I kidney and lung and Stage III endometrial cancer biomarkers from transcriptomic data. These scenarios investigate the use of two types of feature reduction by filters (differentially expressed genes and variance) conjointly with two types of resampling strategies (repeated holdout by distribution-balanced stratified and random stratified) for downstream feature selection through an aggregation of thousands of wrapped machine learning models. Based on our results, we emphasize the advantages of using HEFS approaches to identify complex disease biomarkers, given their ability to produce generalizable and stable results to both data and functional perturbations. Finally, we highlight critical issues that need to be considered in the design of such strategies.

Knockdown of ERN1 disturbs the expression of phosphoserine aminotransferase 1 and related genes in glioblastoma cells

BACKGROUND

Endoplasmic reticulum stress and synthesis of serine are essential for tumor growth, but the mechanism of their interaction is not clarified yet. The overarching goal of this work was to investigate the impact of ERN1 (endoplasmic reticulum to nucleus signaling 1) inhibition on the expression of serine synthesis genes in U87MG glioblastoma cells concerning the suppression of cell proliferation.

METHODS

Wild type U87MG glioblastoma cells and their clones with overexpression of transgenes dnERN1 (without cytoplasmic domain of ERN1) and dnrERN1 (with mutation in endoribonuclease of ERN1), and empty vector (as control) were used. The silencing of ERN1 and XBP1 was also used to inhibition of ERN1 and its function. Gene expression was measured by qPCR.

RESULTS

We show that the expression of PSAT1 and several other related to serine synthesis genes is suppressed in cells with ERN1 inhibition by dissimilar mechanisms: PHGDH gene through ERN1 protein kinase, because its expression was resistant to inhibition of ERN1 endoribonuclease, but ATF4 gene via endoribonuclease of ERN1. However, in the control of PSAT1 and PSPH genes both enzymatic activities of ERN1 signaling protein are involved. At the same time, ERN1 knockdown strongly increased SHMT1 expression, which controls serine metabolism and enhances the proliferation and invasiveness of glioma cells. The level of microRNAs, which have binding sites in PSAT1, SHMT1, and PSPH mRNAs, was also changed in cells harboring dnERN1 transgene. Inhibition of ERN1 suppressed cell proliferation and enzymatic activity of PHGDH, a rate-limiting enzyme for serine synthesis.

CONCLUSION

Changes in the expression of phosphoserine aminotransferase 1 and other genes related to serine synthesis are mediated by diverse ERN1-dependent mechanisms and contributed to suppressed proliferation and enhanced invasiveness of ERN1 knockdown glioblastoma cell.

New insights into PSAT1 as a therapeutic target for myelodysplastic syndrome (MDS)

The metabolomic landscape in myelodysplastic syndrome (MDS) is highly deregulated and presents promising avenues for understanding disease pathogenesis and potential molecular dependencies. Here, we evaluated the transcriptomic landscape in MDS in multiple independent studies focusing more on metabolomics pathways. Identifying molecular dependencies will pave the way for a more precise disease stratification as well as the development of novel personalized treatment strategies. The study adopted a retrospective, cross-sectional approach, utilizing transcriptomic data from multiple MDS studies. The transcriptomic data were then subjected to comprehensive analyses, including differential gene expression, gene enrichment analysis, gene co-expression analysis, protein-protein interaction analyses, and survival analyses. PSAT1 showed a significant upregulation profile in MDS patients. This observed upregulation is correlated with the deregulation of immune-related pathways in MDS samples. This observation suggests a novel role for PSAT1 in immune modulation and potentially in augmenting immune evasion, which may lead to poor prognosis. This was evident in other tumors in the TCGA database, where cancer patients with high PSAT1 expression have a shorter overall survival. This study unveils a novel potential therapeutic avenue in MDS. Identifying the role of the PSAT1 gene sheds light on the disease's intricate biology, highlighting the ongoing cross-talk between metabolism and immune regulation, which may pave the way for innovative treatment modalities.

Ferroptosis: a promising target for fumarate hydratase-deficient tumor therapeutics literature review

Background and Objective

This review aims to investigate the ferroptosis mechanism of fumarate hydratase (FH)-related tumors for the purpose of possible treatment of tumors. Ferroptosis is an iron (Fe)-dependent form of regulated cell death caused by lipid peroxidation on the cell membrane. Studies have implicated FH in tumorigenesis. As mutations in the FH gene alter cellular metabolism and increase tumorigenesis risk, particularly in the kidneys. As most tumor cells require higher amounts of ferrous ions (Fe2+) than normal cells, they are more susceptible to ferroptosis. Recent studies have indicated that ferroptosis is inhibited the pathogenesis and progression of FH-deficient tumors by regulating lipid and iron metabolism, glutathione-glutathione peroxidase 4 (GSH-GPX4), nuclear factor-erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathways. While the Fe2+ content is significantly lower in FH-deficient tumor cells, than that in normal cells. It is promising to promote ferroptosis by increasing the concentration of Fe2+ in cells to achieve the purpose of tumor treatment.

Methods

In this study, we searched for relevant articles on ferroptosis and FH-deficient tumors using PubMed database.

Key Content and Findings

FH is a tumor suppressor. A number of basic studies have shown that the loss of FH plays an important role in hereditary leiomyomas and tumors such as renal cell carcinoma, ovarian cancer, and other tumors. This type of tumor cells can through induce ferroptosis, inhibit proliferation, migration and invasion of tumor cells, increase the sensitivity of tumor cells to chemotherapy, and reverse the drug resistance through various molecular mechanisms. At present, the research on ferroptosis in FH-related tumors is still in the basic experimental stage.

Conclusions

This article reviews the anti-tumor effects and mechanisms of FH and ferroptosis, in order to further explore the medical value of ferroptosis in FH-related tumor therapy.

Coptisine inhibits aggressive and proliferative actions of fibroblast like synoviocytes and exerts a therapeutic potential for rheumatoid arthritis

OBJECTIVE

Coptisine, a natural bioactive small molecular compound extracted from traditional Chinese herb Coptis chinensis, has been shown to exhibit anti-tumor effect. However, its contribution to autoimmune diseases such as rheumatoid arthritis (RA) is unknown. Here, we evaluate the effect of coptisine in controlling fibroblast-like synoviocytes (FLS)-mediated synovial proliferation and aggression in RA and further explore its underlying mechanism(s).

METHODS

FLS were separated from synovial tissues obtained from patients with RA. Protein expression was measured by Western blot or immunohistochemistry. Gene expression was detected by quantitative RT-PCR. The EdU incorporation was used to measure cell proliferation. Migration and invasion were determined by Boyden chamber assay. RNA sequencing analysis was used to seek for the target of coptisine. The in vivo effect of coptisine was evaluated in collagen-induced arthritis (CIA) model.

RESULTS

Treatment with coptisine reduced the proliferation, migration, and invasion, but not apoptosis of RA FLS. Mechanistically, we identified PSAT1, an enzyme that catalyzes serine/one-carbon/glycine biosynthesis, as a novel targeting gene of coptisine in RA FLS. PSAT1 expression was increased in FLS and synovial tissues from patients with RA compared to healthy control subjects. Coptisine treatment or PSAT1 knockdown reduced the TNF-α-induced phosphorylation of p38, ERK1/2, and JNK MAPK pathway. Interestingly, coptisine administration improved the severity of arthritis and reduced synovial PSAT1 expression in mice with CIA.

CONCLUSIONS

Our data demonstrate that coptisine treatment suppresses aggressive and proliferative actions of RA FLS by targeting PSAT1 and sequential inhibition of phosphorylated p38, ERK1/2, and JNK MAPK pathway. Our findings suggest that coptisine might control FLS-mediated rheumatoid synovial proliferation and aggression, and be a novel potential agent for RA treatment.