scholarly journals Downregulation of Lipid Phosphate Phosphatase 3 correlates with Tumor-Infiltrating Immune Cells in Oral Cancer

Author(s):  
Supriya Vishwakarma ◽  
Deepti Joshi ◽  
Ritu Pandey ◽  
Saikat Das ◽  
Sramana Mukhopadhyay ◽  
...  

Abstract Purpose Sphingosine-1-phosphate (S1P), a potent oncogenic lipid. Intracellular levels of S1P are tightly regulated by eight S1P metabolizing enzymes. S1P is synthesized by phosphorylation of sphingosine which is catalyzed by two sphingosine kinases (SphK1 and SphK2). Five lipid phosphatases (two S1P phosphatases and three lipid phosphate phosphatases) reversibly convert S1P back to sphingosine. S1P is ultimately irreversibly degraded by S1P lyase. The role of sphingosine-1-phosphate (S1P) metabolizing enzymes in oral squamous cell carcinoma (OSCC) has not been fully studied. Methods In the current study, we have determined the protein expression of four S1P metabolizing enzymes, namely sphingosine Kinase (SphK) -1, SphK2, S1P phosphatase 1 (SGPP1), and lipid phosphate phosphatase 3 (LPP3) by immunohistochemistry (IHC) and western botting in tumor tissues of 46 OSCC patients and normal oral mucosa (N = 6). Further, we determined the associations of expression of S1P metabolizing enzymes with clinicopathological features of OSCC patients. Results SphK2 and LPP3 exhibit low IRS in OSCC tumors. Importantly, expression of SphK2 and LPP3 was downregulated in malignant cells compared to non-malignant mucosa. Further, LPP3 expression negatively correlated with TNM staging of patients (ρ = -0.307, p = 0.043). Importantly, TCGA analysis revealed that LPP3 expression was positively correlated with infiltration of B cells, neutrophils, macrophages, and dendritic cells in the HNSCC tumors. Conclusion In conclusion, our data show that expression of SphK2 and LPP3 is decreased in OSCC tumors compared to normal mucosa. Thus, LPP3 could represent a potential prognostic marker and therapeutic target for OSCC.

2001 ◽  
Vol 276 (15) ◽  
pp. 11712-11718 ◽  
Author(s):  
Christine J. Birchwood ◽  
Julie D. Saba ◽  
Robert C. Dickson ◽  
Kyle W. Cunningham

In mammalian cells, intracellular sphingosine 1-phosphate (S1P) can stimulate calcium release from intracellular organelles, resulting in the activation of downstream signaling pathways. The budding yeastSaccharomyces cerevisiaeexpresses enzymes that can synthesize and degrade S1P and related molecules, but their possible role in calcium signaling has not yet been tested. Here we examine the effects of S1P accumulation on calcium signaling using a variety of yeast mutants. Treatment of yeast cells with exogenous sphingosine stimulated Ca2+accumulation through two distinct pathways. The first pathway required the Cch1p and Mid1p subunits of a Ca2+influx channel, depended upon the function of sphingosine kinases (Lcb4p and Lcb5p), and was inhibited by the functions of S1P lyase (Dpl1p) and the S1P phosphatase (Lcb3p). The biologically inactive stereoisomer of sphingosine did not activate this Ca2+influx pathway, suggesting that the active S1P isomer specifically stimulates a calcium-signaling mechanism in yeast. The second Ca2+influx pathway stimulated by the addition of sphingosine was not stereospecific, was not dependent on the sphingosine kinases, occurred only at higher doses of added sphingosine, and therefore was likely to be nonspecific. Mutants lacking both S1P lyase and phosphatase (dpl1 lcb3double mutants) exhibited constitutively high Ca2+accumulation and signaling in the absence of added sphingosine, and these effects were dependent on the sphingosine kinases. These results show that endogenous S1P-related molecules can also trigger Ca2+accumulation and signaling. Several stimuli previously shown to evoke calcium signaling in wild-type cells were examined inlcb4 lcb5double mutants. All of the stimuli produced calcium signals independent of sphingosine kinase activity, suggesting that phosphorylated sphingoid bases might serve as messengers of calcium signaling in yeast during an unknown cellular response.


Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1097 ◽  
Author(s):  
Jennifer J. Wolf ◽  
Caleb J. Studstill ◽  
Bumsuk Hahm

The sphingosine 1-phosphate (S1P) metabolic pathway is a dynamic regulator of multiple cellular and disease processes. Identification of the immune regulatory role of the sphingosine analog FTY720 led to the development of the first oral therapy for the treatment of an autoimmune disease, multiple sclerosis. Furthermore, inhibitors of sphingosine kinase (SphK), which mediate S1P synthesis, are being evaluated as a therapeutic option for the treatment of cancer. In conjunction with these captivating discoveries, S1P and S1P-metabolizing enzymes have been revealed to display vital functions during virus infections. For example, S1P lyase, which is known for metabolizing S1P, inhibits influenza virus replication by promoting antiviral type I interferon innate immune responses. In addition, both isoforms of sphingosine kinase have been shown to regulate the replication or pathogenicity of many viruses. Pro- or antiviral activities of S1P-metabolizing enzymes appear to be dependent on diverse virus–host interactions and viral pathogenesis. This review places an emphasis on summarizing the functions of S1P-metabolizing enzymes during virus infections and discusses the opportunities for designing pioneering antiviral drugs by targeting these host enzymes.


2005 ◽  
Vol 33 (6) ◽  
pp. 1370-1374 ◽  
Author(s):  
S. Pyne ◽  
J.S. Long ◽  
N.T. Ktistakis ◽  
N.J. Pyne

Mammalian LPPs (lipid phosphate phosphatases) are integral membrane proteins that belong to a superfamily of lipid phosphatases/phosphotransferases. They have broad substrate specificity in vitro, dephosphorylating PA (phosphatidic acid), S1P (sphingosine 1-phosphate), LPA (lysophosphatidic acid) etc. Their physiological role may include the attenuation of S1P- and LPA-stimulated signalling by virtue of an ecto-activity (i.e. dephosphorylation of extracellular S1P and LPA), thereby limiting the activation of LPA- and S1P-specific G-protein-coupled receptors at the cell surface. However, our recent work suggests that an intracellular action of LPP2 and LPP3 may account for the reduced agonist-stimulated p42/p44 mitogen-activated protein kinase activation of HEK-293 (human embryonic kidney 293) cells. This may involve a reduction in the basal levels of PA and S1P respectively and the presence of an early apoptotic phenotype under conditions of stress (serum deprivation). Additionally, we describe a model whereby LPP2, but not LPP3, may be functionally linked to the phospholipase D1-derived PA-dependent recruitment of sphingosine kinase 1 to the perinuclear compartment. We also consider the potential regulatory mechanisms for LPPs, which may involve oligomerization. Lastly, we highlight many aspects of the LPP biology that remain to be fully defined.


2017 ◽  
Vol 35 (2) ◽  
pp. 139-141 ◽  
Author(s):  
Supriya Vishwakarma ◽  
Rahul Agarwal ◽  
Sudhir K. Goel ◽  
Rajendra K. Panday ◽  
Renu Singh ◽  
...  

2004 ◽  
Vol 279 (50) ◽  
pp. 52487-52492 ◽  
Author(s):  
Maria L. Allende ◽  
Teiji Sasaki ◽  
Hiromichi Kawai ◽  
Ana Olivera ◽  
Yide Mi ◽  
...  

Sphingosine-1-phosphate (S1P), a lipid signaling molecule that regulates many cellular functions, is synthesized from sphingosine and ATP by the action of sphingosine kinase. Two such kinases have been identified, SPHK1 and SPHK2. To begin to investigate the physiological functions of sphingosine kinase and S1P signaling, we generated mice deficient in SPHK1.Sphk1null mice were viable, fertile, and without any obvious abnormalities. Total SPHK activity in mostSphk1-/-tissues was substantially, but not completely, reduced indicating the presence of multiple sphingosine kinases. S1P levels in most tissues from theSphk1-/- mice were not markedly decreased. In serum, however, there was a significant decrease in the S1P level. Although S1P signaling regulates lymphocyte trafficking, lymphocyte distribution was unaffected in lymphoid organs ofSphk1-/- mice. The immunosuppressant FTY720 was phosphorylated and elicited lymphopenia in theSphk1null mice showing that SPHK1 is not required for the functional activation of this sphingosine analogue prodrug. The results with theseSphk1null mice reveal that some key physiologic processes that require S1P receptor signaling, such as vascular development and proper lymphocyte distribution, can occur in the absence of SPHK1.


2021 ◽  
Vol 11 (2) ◽  
pp. 308-314
Author(s):  
Zengbo Wu ◽  
Yan Yan ◽  
Xianzhuo Chen ◽  
Yanling Liu ◽  
Dinggen Chen

miR15b and SALL4 are involved in a variety of tumor progression. The roles of miR15b and SALL4 in oral squamous cell carcinoma (OSCC) remains unclear. The tumors and normal mucosa of OSCC patients were collected to detect miR15b and SALL4 level by Real-time PCR and analyze their correlation with OSCC clinicopathological features. Oral cancer Tca8113 cells were separated into control group; miR15b mimics group and miR15b inhibitor group followed by analysis of SALL4 expression, cell survival by MTT assay; cell invasion by Transwell chamber assay, as well as expression of N-cadherin and Vimentin and correlated with TNM stage, tumor volume and metastasis, and positively with differentiation TGF-β by Western blot. miR15b expression was decreased and SALL4 expression was increased in OSCC tumor tissues. miR15b was negatively degree (P < 0.05), whereas, opposite correlation of SALL4 with the above parameters was found (P < 0.05). miR15b and SALL4 were negatively correlated. MiR15b mimics significantly up-regulated MiR15b, decreased SALL4 expression, inhibited Tca8113 cell proliferation and invasion, as well as reduced N-cadherin, Vimentin and TGF-βexpression (P < 0.05). Opposite results were found in MiR15b inhibitor group. MiR15b expression is decreased and SALL 4 is increased in OSCC tumor tissues. MiR15b and SALL4 is closely related to OSCC clinicopathological features. MiR15b regulates the expression of EMT-related genes and TGF-β, thereby altering the proliferation and invasion of OSCC cells.


Author(s):  
Luciana Petti ◽  
Giulia Rizzo ◽  
Federica Rubbino ◽  
Sudharshan Elangovan ◽  
Piergiuseppe Colombo ◽  
...  

Abstract Background Sphingosine-1-phosphate receptor 2 (S1PR2) mediates pleiotropic functions encompassing cell proliferation, survival, and migration, which become collectively de-regulated in cancer. Information on whether S1PR2 participates in colorectal carcinogenesis/cancer is scanty, and we set out to fill the gap. Methods We screened expression changes of S1PR2 in human CRC and matched normal mucosa specimens [N = 76]. We compared CRC arising in inflammation-driven and genetically engineered models in wild-type (S1PR2+/+) and S1PR2 deficient (S1PR2−/−) mice. We reconstituted S1PR2 expression in RKO cells and assessed their growth in xenografts. Functionally, we mimicked the ablation of S1PR2 in normal mucosa by treating S1PR2+/+ organoids with JTE013 and characterized intestinal epithelial stem cells isolated from S1PR2−/−Lgr5-EGFP- mice. Results S1PR2 expression was lost in 33% of CRC; in 55%, it was significantly decreased, only 12% retaining expression comparable to normal mucosa. Both colitis-induced and genetic Apc+/min mouse models of CRC showed a higher incidence in size and number of carcinomas and/or high-grade adenomas, with increased cell proliferation in S1PR2−/− mice compared to S1PR2+/+ controls. Loss of S1PR2 impaired mucosal regeneration, ultimately promoting the expansion of intestinal stem cells. Whereas its overexpression attenuated cell cycle progression, it reduced the phosphorylation of AKT and augmented the levels of PTEN. Conclusions In normal colonic crypts, S1PR2 gains expression along with intestinal epithelial cells differentiation, but not in intestinal stem cells, and contrasts intestinal tumorigenesis by promoting epithelial differentiation, preventing the expansion of stem cells and braking their malignant transformation. Targeting of S1PR2 may be of therapeutic benefit for CRC expressing high Lgr5. Graphical Abstract. Schematic drawing of the role of S1PR2 in normal mucosa and colorectal cancer. In the normal mucosa, S1PR2 is highly expressed by differentiated cells at the upper region of both colon and intestinal crypts (S1PR2 ON), but not by the undifferentiated stem cell at the base of the crypts (S1PR2 OFF), in which acts as a negative proliferative regulator promoting epithelial differentiation. Its loss leads to the expansion of stem cells and reduced levels of PTEN and Axin-2, two negative regulators respectively of PI3K/AKT and Wnt signaling that control β-catenin signaling. The translocation of β-catenin into the nucleus promotes the transcription of target genes involved in the proliferation and malignant transformation. Thereby, S1PR2 works in the intestine as a tumor suppressor


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