Identification of LPCAT1 expression as a potential prognostic biomarker guiding treatment choice in acute myeloid leukemia

Phospholipid Acyltransferases: Characterization and Involvement of the Enzymes in Metabolic and Cancer Diseases

This review delves into the enzymatic processes governing the initial stages of glycerophospholipid (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine) and triacylglycerol synthesis. The key enzymes under scrutiny include GPAT and AGPAT. Additionally, as most AGPATs exhibit LPLAT activity, enzymes participating in the Lands cycle with similar functions are also covered. The review begins by discussing the properties of these enzymes, emphasizing their specificity in enzymatic reactions, notably the incorporation of polyunsaturated fatty acids (PUFAs) such as arachidonic acid and docosahexaenoic acid (DHA) into phospholipids. The paper sheds light on the intricate involvement of these enzymes in various diseases, including obesity, insulin resistance, and cancer. To underscore the relevance of these enzymes in cancer processes, a bioinformatics analysis was conducted. The expression levels of the described enzymes were correlated with the overall survival of patients across 33 different types of cancer using the GEPIA portal. This review further explores the potential therapeutic implications of inhibiting these enzymes in the treatment of metabolic diseases and cancer. By elucidating the intricate enzymatic pathways involved in lipid synthesis and their impact on various pathological conditions, this paper contributes to a comprehensive understanding of these processes and their potential as therapeutic targets.

The validation and clinical significance of LPCAT1 down-regulation in acute myeloid leukemia

BACKGROUND

Overexpression of lysophosphatidylcholine acyltransferase 1 (LPCAT1) has been found in various solid cancers and is associated with disease progression, metastasis, and recurrence. However, the expression pattern of LPCAT1 in acute myeloid leukemia (AML) bone marrow remains unknown. The present study aimed to compare LPCAT1 expression differences in bone marrow samples from AML patients and healthy controls and assess the clinical relevance of LPCAT1 in AML.

METHODS AND RESULTS

LPCAT1 expression in bone marrow was significantly lower in AML than in healthy controls predicted by public databases. Furthermore, real-time quantitative PCR (RQ-PCR) validated that LPCAT1 expression in bone marrow was significantly down-regulated in AML compared to healthy controls [0.056 (0.000-0.846) vs 0.253 (0.031-1.000)]. The DiseaseMeth version 2.0 and The Cancer Genome Atlas analysis revealed that the LPCAT1 promoter was hypermethylated in AML, and there was a strong negative correlation between LPCAT1 expression and methylation (R = - 0.610, P < 0.001). RQ-PCR revealed that the frequency of LPCAT1 low expression was lower in the FAB-M4/M5 subtype than in the other subtypes (P = 0.018). The ROC curve revealed that LPCAT1 expression could serve as a potential diagnostic marker for differentiating AML from controls with an area under the ROC curve of 0.819 (95% CI 0.743-0.894, P < 0.001). In cytogenetically normal AML, patients with LPCAT1 low expression had significantly longer overall survival than those without LPCAT1 low expression (median 19 versus 5.5 months, P = 0.036).

CONCLUSIONS

LPCAT1 is down-regulated in AML bone marrow, and LPCAT1 down-regulation could be used as a potential biomarker for AML diagnosis and prognosis.

Prognostic value of an eighteen-genes panel in acute myeloid leukemia by analyzing TARGET and TCGA databases

BACKGROUND

Acute myeloid leukemia (AML) has a poor prognosis, and the current 5-year survival rate is less than 30%.

OBJECTIVE

The present study was designed to identify the significant genes closely related to AML prognosis and predict the prognostic value by constructing a risk model based on their expression.

METHODS

Using bioinformatics (Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, univariate and multivariate Cox regression analysis, Kaplan-Meier survival analysis, and receiver operating characteristic (ROC) analysis) to identify a prognostic gene signature for AML. Finally, The Cancer Genome Atlas (TCGA) database was used to validate this prognostic signature.

RESULTS

Based on univariate and multivariate Cox regression analysis, eighteen prognostic genes were identified, and the gene signature and risk score model were constructed. Multivariate Cox analysis showed that the risk score was an independent prognostic factor [hazard ratio (HR) = 1.122, 95% confidence interval (CI) = 1.067-1.180, P< 0.001]. ROC analysis showed a high predictive value of the risk model with an area under the curve (AUC) of 0.705.

CONCLUSIONS

This study evaluated a potential prognostic signature with eighteen genes and constructed a risk model significantly related to the prognosis of AML patients.

LPCAT1 functions as an oncogene in cervical cancer through mediating JAK2/STAT3 signaling

Cervical cancer is a major gynecological tumor worldwide. Unfortunately, the molecular mechanisms involved in cervical cancer tumorigenesis still requires more clarification. Lysophosphatidylcholine acyltransferase 1 (LPCAT1), an enzyme involved in phosphatidylcholine metabolism, has been reported to regulate the proliferation, epithelial-mesenchymal transition (EMT) and recurrence of malignancies. Here in our study, we found that LPAT1 was over-expressed in clinical cervical cancer tissues, and its high expression was closely correlated with poor outcomes of patients. We further showed that LPCAT1 knockdown remarkably restrained the proliferation, migration and invasion of cervical cancer cells, while it significantly induced apoptosis. RNA-seq and bioinformatics assays initially showed that interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) pathway was a key mechanism for LPCAT1 to regulate cervical cancer progression. LPCAT1 silence strongly decreased IL-6, p-Janus kinase 2 (JAK2) and p-STAT3 expression levels in cervical cancer cells. Similarly, the expression levels of IL-6/STAT3 target genes were also highly down-regulated in cervical cancer cells with LPCAT1 deletion. Importantly, we found that human recombinant IL-6 addition considerably abolished the function of LPCAT1-knockdown to suppress the proliferation and EMT process in cervical cancer cells, accompanied with mitigated apoptotic cell death. Furthermore, our animal experiment results validated that stable LPCAT1 deletion efficiently reduced the tumor growth rates of xenograft mouse models and lung metastasis in vivo. Collectively, all our findings revealed that LPCAT1 may be a promising alternative prognostic biomarker and therapeutic target for cervical cancer through regulating JAK2/STAT3 signaling pathway.

Overexpression of LPCAT1 enhances endometrial cancer stemness and metastasis by changing lipid components and activating the TGF/β-Smad2/3 signaling pathway

The incidence of endometrial cancer (EC) increases annually and tends to occur in younger women. A particularly important relationship exists between EC and metabolic disorders. As one of the most important components of lipid metabolism, phospholipids play an indispensable role in metabolic balance. LPCAT1 is a key enzyme regulating phospholipid metabolism. In this study, we perform further investigations to seek mechanistic insight of LPCAT1 in EC. Our results demonstrate that silencing of LPCAT1 inhibits the growth of endometrial cancer, while overexpression of LPCAT1 results in enhanced stemness and metastasis in endometrial cancer cell lines. Meanwhile, the contents of various phospholipids including phosphatidylethanolamine (PE), phosphatidylcholine (PC), and triglyceride (TG) change significantly after overexpression of LPCAT1. In addition, through RNA-sequencing and western blot analysis, we observe that the TGF-β/Smad2/3 signaling pathway is of great importance in the tumor-promoting function of LPCAT1. LPCAT1 promotes the expressions of stem cell-related transcription factors and epithelial-mesenchymal transition (EMT) related proteins through the TGF-β/Smad2/3 signaling pathway. Moreover, we find that TSI-01, which can inhibit the activity of LPCAT1, is able to restrain the proliferation of EC cell lines and promote cell apoptosis. Collectively, we demonstrate that LPCAT1 enhances the stemness and metastasis of EC by activating the TGF-β/Smad2/3 signaling pathway and that TSI-01 may have potential use for the treatment of EC.

Comprehensive Analysis of LPCATs Highlights the Prognostic and Immunological Values of LPCAT1/4 in Hepatocellular Carcinoma

Background

The prognosis of patients with advanced hepatocellular carcinoma (HCC) remains poor. Lipid remodeling modulators are considered promising therapeutic targets of cancers, owing to their functions of facilitating cancer cells’ adaption to the limited environment. Lysophosphatidylcholine acyltransferases (LPCATs) are enzymes regulating bio-membrane remodeling, whose roles in HCC have not been fully illuminated.

Methods

Multiple bioinformatic tools were applied to comprehensively evaluate the expression, genetic alterations, clinical relevance, prognostic values, DNA methylation, biological functions, and correlations with immune infiltration of LPCATs in HCC.

Results

We found LPCAT1 was significantly overexpressed and the most frequently altered in HCC. The high-expression of LPCAT1/4 indicated clinicopathological advancements and poor prognoses of HCC patients. Even though the global DNA methylation of LPCATs in HCC showed no significant difference with that in normal liver, the hypermethylation of numerous CpG sites of them implied worse survivals of HCC patients. Thirty LPCATs’ interactive genes were identified, which were generally membrane components and partook in phospholipid metabolism pathways. Finally, we found the expression of LPCATs was extensively positively correlated with the infiltration of various stimulatory and suppressive tumor-infiltrating immune cells (TIICs) in the tumor microenvironment.

Conclusion

This study addressed LPCAT1/4 were potential prognostic and immunotherapeutic biomarkers of HCC targeting bio-membrane lipid remodeling.

A rapid increase in lysophospholipids after geranylgeranoic acid treatment in human hepatoma-derived HuH-7 cells revealed by metabolomics analysis

Geranylgeranoic acid (GGA) was developed as a preventative agent against second primary hepatoma, and was reported to induce cell death in human hepatoma cells via Toll-like receptor 4 (TLR4)-mediated pyroptosis. We recently reported that GGA is enzymatically biosynthesized from mevalonic acid in human hepatoma-derived HuH-7 cells and that endogenous GGA is found in most rat organs including the liver. An unbiased metabolomics analysis of ice-cold 50% acetonitrile extracts from control and GGA-treated cells was performed in this study to characterize the intracellular metabolic changes in GGA-induced pyroptosis and to analyze their relationship with the mechanism of GGA-induced cell death. The total positive ion chromatograms of the cellular extracts in ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were apparently unchanged after GGA treatment, but an orthogonal partial least squares-discriminant analysis score plot clearly discriminated the intracellular metabolite profiles of GGA-treated cells from that of control cells. S-plot analysis revealed 15 potential biomarkers up-regulated by 24-h GGA treatment according to their variable importance in the projection value of more than 1, and the subsequent metabolomics analysis identified nine of these metabolites as a group of lysophospholipids containing lysophosphatidylcholine with C16:0, C20:4, or C20:3 fatty acids. The possible roles of these lysophospholipids in GGA-induced pyroptosis are discussed.

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Metabolomics analysis was performed on geranylgeranoic acid (GGA)-treated cells.

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Total positive ion chromatograms were apparently similar after GGA treatment.

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The OPLS-DA score plot distinguished the GGA-treated cells from control cells.

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The S-plot analysis revealed GGA-induced upregulation of lysophospholipids.

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The possible roles of lysophospholipids in GGA-induced pyroptosis are discussed.

LPCAT1 overexpression promotes the progression of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) remains one of the most common malignant neoplasms. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) plays a key role in the lipid remodelling and is correlated with various neoplasms. Nonetheless, the biological functions and molecular mechanisms of LPCAT1 underlying HCC remain obscure.

METHODS

In the present study, we investigated the role of LPCAT1 in the progression of HCC. In-house RT-qPCR, tissue microarrays, and immunohistochemistry were performed to detect the expression levels and the clinical value of LPCAT1 in HCC. External datasets were downloaded to confirm the results. Proliferation, migration, invasiveness, cell cycle, and apoptosis assays were conducted to reveal the biological effects LPCAT1 has on SMMC-7721 and Huh7 cells. HCC differentially expressed genes and LPCAT1 co-expressed genes were identified to explore the molecular mechanisms underlying HCC progression.

RESULTS

LPCAT1 showed upregulated expression in 3715 HCC specimens as opposed to 3105 non-tumour specimens. Additionally, LPCAT1 might be an independent prognostic factor for HCC. LPCAT1-knockout hampered cellular proliferation, migration, and metastasis in SMMC-7721 and Huh7 cells. More importantly, the cell cycle and chemical carcinogenesis were the two most enriched signalling pathways.

CONCLUSIONS

The present study demonstrated that increased LPCAT1 correlated with poor prognosis in HCC patients and fuelled HCC progression by promoting cellular growth, migration, and metastasis.

Elevated expression of LPCAT1 predicts a poor prognosis and is correlated with the tumour microenvironment in endometrial cancer

Background

Endometrial cancer (EC) is one of the three malignant reproductive tumours that threaten womens lives and health. Glycerophospholipids (GPLs) are important bioactive lipids involved in various physiological and pathological processes, including cancer. Immune infiltration of the tumour microenvironment (TME) is positively associated with the overall survival in EC. Exploring GPL-related factors associated with the TME in endometrial cancer can aid in the prognosis of patients and provide new therapeutic targets.

Methods

Differentially expressed GPL-related genes were identified from TCGA-UCEC datasets and the Molecular Signatures Database (MSigDB). Univariate Cox regression analysis was used to select GPL-related genes with prognostic value. The Random forest algorithm, LASSO algorithm and PPI network were used to identify critical genes. ESTIMATEScore was calculated to identify genes associated with the TME. Then, differentiation analysis and survival analysis of LPCAT1 were performed based on TCGA datasets. GSE17025 and immunohistochemistry (IHC) verified the results of the differentiation analysis. An MTT assay was then conducted to determine the proliferation of EC cells. GO and KEGG enrichment analyses were performed to explore the underlying mechanism of LPCAT1. In addition, we used the ssGSEA algorithm to explore the correlation between LPCAT1 and cancer immune infiltrates.

Results

Twenty-three differentially expressed GPL-related genes were identified, and eleven prognostic genes were selected by univariate Cox regression analysis. Four significant genes were identified by two different algorithms and the PPI network. Only LPCAT1 was significantly correlated with the tumour microenvironment. Then, we found that LPCAT1 was highly expressed in tumour samples compared with that in normal tissues, and lower survival rates were observed in the groups with high LPCAT1 expression. Silencing of LPCAT1 inhibited the proliferation of EC cells. Moreover, the expression of LPCAT1 was positively correlated with the histologic grades and types. The ROC curve indicated that LPCAT1 had good prognostic accuracy. Receptor ligand activity, pattern specification process, regionalization, anterior/posterior pattern specification and salivary secretion pathways were enriched as potential targets of LPCAT1. By using the ssGSEA algorithm, fifteen kinds of tumor-infiltrating cells (TICs) were found to be correlated with LPCAT1 expression.

Conclusion

These findings suggested that LPCAT1 may act as a valuable prognostic biomarker and be correlated with immune infiltrates in endometrial cancer, which may provide novel therapy options for and improved treatment of EC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01965-1.