Targeting Sphingosine-1-Phosphate Signaling in Breast Cancer

Melanophilin inhibit the growth and lymph node metastasis of triple negative breast cancer via the NONO-SPHK1-S1P axis

BACKGROUND

Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with the worst prognosis, and there are no targeted treatments available. TNBC patients are more likely to develop metastases and relapse than patients with other breast cancer subtypes. Lymph node metastasis is the first sign of metastatic spread. We aimed to characterize the mechanism of lymph node metastasis in TNBC to provide a new strategy for the treatment of TNBC.

METHODS

Gene Expression Omnibus (GEO) TNBC database was utilized to screen for genes related to N staging. Screening the downstream target of Melanophilin (MLPH) in TNBC through RNA sequencing (RNA seq) analysis. Protein mass spectrometry was utilized to analyze the protein which interacts with MLPH, and RNA binding protein immunoprecipitation and quantitative real-time PCR (RIP qPCR) were utilized to verify the regulation of sphingosine kinase 1 (SPHK1) expression by MLPH through Non-POU domain-containing octamer-binding protein (NONO). Cell functional assays and in vivo models experiments further confirmed the effects of MLPH on proliferation and lymph node metastasis of TNBC through the SPHK1-S1P axis.

RESULTS

MLPH is downregulated in TNBC and inhibits tumor growth and lymph node metastasis though the MLPH-NONO-SPHK1-S1P pathway. NONO was identified as an essential factor involved in SPHK1 mRNA splicing. MLPH interacts with NONO to inhibit SPHK1 mRNA splicing of SPHK1, which reduces the content of S1P, thereby inhibiting growth and lymph node metastasis in TNBC.

CONCLUSIONS

This study preliminarily elucidated a mechanism underlying lymph node metastasis in TNBC and identified the role of the MLPH-NONO-SPHK1-S1P axis in regulating proliferation and lymph node metastasis in TNBC. These findings may help design strategies for predicting and treating metastasis in TNBC.

Lipid dysregulation in triple negative breast cancer: Insights from mass spectrometry-based approaches

Triple negative breast cancer (TNBC) has the worst prognosis among breast cancers due to its aggressive nature and the absence of targeted treatments. Development of novel anti-cancer drugs for TNBC faces challenges stemming from its heterogeneity and high potential for metastasis. Metabolomics can be a useful technology in finding novel therapeutic targets and probing the heterogeneity of TNBC. Metabolomics has been enabled by advancements in mass spectrometry (MS)-based platforms that facilitated comprehensive profiling of TNBC metabolism. This review provides an overview of metabolomic changes in TNBC with emphasis on lipid alterations, and describes the key MS analytical techniques, providing the necessary background for examining the role of lipids in TNBC development.

Sphingosine 1-phosphate acts as proliferative and fibrotic cue in leiomyoma cells

OBJECTIVE

To determine whether the bioactive sphingolipid sphingosine 1-phosphate (S1P) modulates cellular proliferation and synthesis of fibrotic proteins in leiomyoma differently than myometrial cells.

DESIGN

A basic science study using human leiomyoma and myometrial cells.

SUBJECTS

Not applicable. This is an in vitro study performed on cellular models.

EXPOSURE

Leiomyoma and myometrial cells were treated with S1P, as well as with selective antagonists for S1P-specific G protein-coupled receptors and secondarily with inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and ezrin.

MAIN OUTCOME MEASURES

The main outcome measures included cellular proliferation and fibrogenesis. Bromodeoxyuridine Cell Proliferation Assay was employed to measure deoxyribonucleic acid synthesis and proliferation, whereas western blot analysis was used to assess the expression of the fibrotic markers N-cadherin, α-smooth muscle actin, transgelin, and collagen type I alpha 1.

RESULTS

Sphingosine 1-phosphate stimulates cellular proliferation of leiomyoma but not myometrial cells. The mitogenic effect elicited by S1P relies on the engagement of its specific receptor S1P2 and is mediated by ERK1/2 and ezrin activation. Furthermore, S1P exerts a profibrotic effect in a S1P-specific G protein-coupled receptor-dependent manner in leiomyoma but not myometrial cells.

CONCLUSIONS

These results, besides extending the knowledge on the molecular mechanism underlying uterine leiomyoma development and fibrosis, demonstrate the pathogenetic role of S1P in leiomyoma and support the rationale for targeting S1P signaling pathway as innovative potential treatment.

The Role of Sphingolipid Metabolism in Pregnancy-Associated Breast Cancer After Chemotherapy

BACKGROUND

The aim of our study was to determine the role of sphingolipids, which control proliferation and apoptosis, in the placenta of pregnant women with pregnancy-associated breast cancer (PABC) after chemotherapy compared with healthy patients.

METHODS

We analyzed (by the PCR method) the gene expression of key sphingolipid metabolism enzymes (sphingomyelinases (SMPD1 and SMPD3), acid ceramidase (ASAH1), ceramide synthases (CERS 1-6), sphingosine kinase1 (SPHK1), sphingosine-1-phosphate lyase 1 (SGPL1), and sphingosine-1-phosphate receptors (S1PR1, S1PR2, and S1PR3)) and the content of subspecies of ceramides, sphingosine, and sphingosine-1-phosphate in seven patients with PABC after chemotherapy and eight healthy pregnant women as a control group.

RESULTS

We found a significant increase in the expression of genes of acid ceramidase (ASAH1), sphingosine-1-phosphate lyase 1 (SGPL1), sphingosine kinase (SPHK1), and ceramide synthases (CERS 1-3, 5, 6) in the samples of patients with PABC during their treatment with cytostatic chemotherapy. The increase in the expression of the enzymes' genes was not accompanied by changes in the content of the studied sphingolipids. Such significant changes in the expression of genes controlling the level of CER, sphingosine, and S1P may indicate their ability to initiate the metabolism of pro-apoptotic and anti-apoptotic sphingolipids in the placenta of pregnant women with cancer undergoing chemotherapy in order to maintain levels typical of the placenta of healthy women.

CONCLUSIONS

Our results may indicate the promising mechanism of placenta protection during chemotherapy for pregnant women with breast cancer and, consequently, of the newborn. This protective effect of the placenta and especially for the newborn has been discovered for the first time and requires more careful study.

A First-in-Human Phase I Study of BXQ-350, a First-in-Class Sphingolipid Metabolism Regulator, in Patients with Advanced/Recurrent Solid Tumors or High-Grade Gliomas

PURPOSE

BXQ-350, a nanovesicle formulation of saposin C, is an allosteric sphingolipid metabolism regulator that increases proapoptotic ceramide and decreases oncogenic sphingosine-1-phosphate levels. We conducted a first-in-human phase I study of BXQ-350.

PATIENTS AND METHODS

Adults (≥18 years old) with advanced/recurrent, treatment-refractory solid tumors or high-grade gliomas received BXQ-350 intravenously in five dose cohorts (0.7-2.4 mg/kg) in a 3+3 dose escalation and expansion design. The primary endpoints during dose escalation were dose-limiting toxicities and maximum tolerated dose; the primary objective in expansion parts was assessment of antitumor activity (RECIST v1.1/Response Assessment in Neuro-Oncology criteria).

RESULTS

Eighty-six patients were enrolled. Dose-limiting toxicities were not observed during dose escalation (n = 18), and a maximum tolerated dose was not identified. An additional 68 patients received the 2.4 mg/kg dose. Nine patients (10%) discontinued due to adverse events. The most common treatment-related adverse events were nausea (24%) and fatigue (23%). Eight patients had a progression-free survival of ≥6 months. Two of these achieved a partial response, and six had stable disease, among whom three had a reduction in ≥1 target lesion. Of those with progression-free survival of ≥6 months, seven remained on study for >12 months, five for >24 months, and after 7 years, two remained on study without disease progression.

CONCLUSIONS

BXQ-350 was well-tolerated as monotherapy at doses up to 2.4 mg/kg. It provided some lasting clinical benefit in patients with recurrent solid malignancies across several tumor types, consistent with a decreased systemic sphingosine-1-phosphate/ceramide metabolic rheostat. BXQ-350 warrants further clinical investigation alone and combined with standard of care for advanced solid tumors.

Explore the Role of the Sphingosine-1-Phosphate Signalling as a Novel Promising Therapeutic Target for the Management of Parkinson's Disease

Sphingosine-1-phosphate (S1P) is a cellular signalling molecule derived from sphingosine, which is a pro-apoptotic sphingolipid. Sphingolipids control various cellular actions like growth, homeostasis, and stress-related responses. The main sources of S1P in our body are erythrocytes. S1P controls both cellular mediators and other second messengers intracellularly. The S1P receptor also helps in inflammatory and neuroprotective effects (required to manage of Parkinson's). A large number of anti-Parkinson drugs are available, but still, there is a need for more effective and safer drugs. S1P and its receptors could be targeted as novel drugs due to their involvement in neuro-inflammation and Parkinson's. The present review effort to explore the biological role of S1P and related receptors, for their possible involvement in PD; furthermore. Overall, S1P and other related metabolizing enzymes have significant therapeutic opportunities for Parkinson's disease along with other neurological disorders.

Integrated Metabolomics and Transcriptomics Analysis of Anacardic Acid Inhibition of Breast Cancer Cell Viability

Anacardic acid (AnAc) inhibits the growth of estrogen receptor α (ERα)-positive MCF-7 breast cancer (BC) cells and MDA-MB-231 triple-negative BC (TNBC) cells, without affecting primary breast epithelial cells. RNA sequencing (seq) and network analysis of AnAc-treated MCF-7 and MDA-MB-231 cells suggested that AnAc inhibited lipid biosynthesis and increased endoplasmic reticulum stress. To investigate the impact of AnAc on cellular metabolism, a comprehensive untargeted metabolomics analysis was performed in five independent replicates of control versus AnAc-treated MCF-7 and MDA-MB-231 cells and additional TNBC cell lines: MDA-MB-468, BT-20, and HCC1806. An analysis of the global metabolome identified key metabolic differences between control and AnAc-treated within each BC cell line and between MCF-7 and the TNBC cell lines as well as metabolic diversity among the four TNBC cell lines, reflecting TNBC heterogeneity. AnAc-regulated metabolites were involved in alanine, aspartate, glutamate, and glutathione metabolism; the pentose phosphate pathway; and the citric acid cycle. Integration of the transcriptome and metabolome data for MCF-7 and MDA-MB-231 identified Signal transduction: mTORC1 downstream signaling in both cell lines and additional cell-specific pathways. Together, these data suggest that AnAc treatment differentially alters multiple pools of cellular building blocks, nutrients, and transcripts resulting in reduced BC cell viability.