sphingosine-1-phosphate and Urinary-Bladder-Neoplasms

It has been proven that tumour growth and progression are regulated by a variety of mediators released during the inflammatory process preceding the tumour appearance, but the role of inflammation in the development of bladder cancer is ambiguous. This study was designed around the hypothesis that sphingosine-1-phosphate (S1P), as a regulator of several cellular processes important in both inflammation and cancer development, may exert some of the pro-tumorigenic effects indirectly due to its ability to regulate the expression of human cathelicidin (hCAP-18). LL-37 peptide released from hCAP-18 is involved in the development of various types of cancer in humans, especially those associated with infections. Using immunohistological staining, we showed high expression of hCAP-18/LL-37 and sphingosine kinase 1 (the enzyme that forms S1P from sphingosine) in human bladder cancer cells. In a cell culture model, S1P was able to stimulate the expression and release of hCAP-18/LL-37 from human bladder cells, and the addition of LL-37 peptide dose-dependently increased their proliferation. Additionally, the effect of S1P on LL-37 release was inhibited in the presence of FTY720P, a synthetic immunosuppressant that blocks S1P receptors. Together, this study presents the possibility of paracrine relation in which LL-37 production following cell stimulation by S1P promotes the development and growth of bladder cancer.

Topics: Antimicrobial Cationic Peptides; Cathelicidins; Cell Growth Processes; Humans; Inflammation; Lysophospholipids; Sphingosine; Urinary Bladder Neoplasms

Hypoxia facilitates an aggressive phenotype and immune evasion in solid tumors including bladder cancer (BC). Sphingosine kinase 1 (SphK1) is aberrantly expressed and correlated with poor prognosis in BC patients. However, its roles in hypoxia-evoked malignancies and immune evasion in BC remain elusive.. The expression of SphK1 in BC tissues was analysed using a bioinformatics database. BC cells were transfected with si-SphK1 or recombinant HIF-1α plasmids under hypoxic conditions. The mRNA level, activity and protein expression of SphK1 were determined. Transwell assay was performed to evaluate cell invasion. After co-culture with natural killer (NK) cells, NK cell cytotoxicity to BC cells was assessed. The involvement of sphingosine-1-phosphate (S1P)/HIF-1α signaling was analysed by ELISA, qRT-PCR and western blot.. UALCAN and GEPIA database confirmed high expression of SphK1 in BC tissues. Moreover, hypoxia increased the expression and activity of SphK1. Loss of SphK1 inhibited hypoxia-induced cell invasion. IL-2 induced NK cell activation by secreting TNF-α and IFN-γ. Hypoxia antagonized NK cell activation-evoked cytotoxicity to BC cells. Intriguingly, SphK1 knockdown reversed hypoxia-induced cell resistance to NK cell killing. Mechanically, SphK1 loss inhibited hypoxia-activated the S1P/HIF-1α signaling. However, S1P addition reversed the inhibitory effects of SphK1 down-regulation on hypoxia-activated S1P/HIF-1α signaling. Notably, reactivating HIF-1α overturned the suppressive roles of SphK1 loss in decreasing hypoxia-induced cell invasion and resistance to NK cell cytotoxicity.. Targeting SphK1 may inhibit hypoxia-evoked invasion and immune evasion via the S1P/HIF-1α signaling, indicating a promising therapeutic target for BC.

Topics: Carcinoma; Cell Death; Humans; Hypoxia; Interleukin-2; Killer Cells, Natural; Oncogenes; Phosphotransferases (Alcohol Group Acceptor); RNA, Messenger; Tumor Necrosis Factor-alpha; Urinary Bladder; Urinary Bladder Neoplasms

S1PR1 signaling has been shown to restrain the number and function of regulatory T (Treg) cells in the periphery under physiological conditions and in colitis models, but its role in regulating tumor-associated T cells is unknown. Here, we show that S1PR1 signaling in T cells drives Treg accumulation in tumors, limits CD8(+) T cell recruitment and activation, and promotes tumor growth. T-cell-intrinsic S1PR1 affects Treg cells, but not CD8(+) T cells, as demonstrated by adoptive transfer models and transient pharmacological S1PR1 modulation. An increase in S1PR1 in CD4(+) T cells promotes STAT3 activation and JAK/STAT3-dependent Treg tumor migration, whereas STAT3 ablation in T cells diminishes tumor-associated Treg accumulation and tumor growth. Our study demonstrates a stark contrast between the consequences of S1PR1 signaling in Treg cells in the periphery versus tumors.

Topics: Animals; Female; Humans; Janus Kinases; Lymphocyte Activation; Lysophospholipids; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptors, Lysosphingolipid; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; STAT3 Transcription Factor; T-Lymphocytes, Regulatory; Urinary Bladder Neoplasms

Mechanisms by which cancer cells communicate with the host organism to regulate lung colonization/metastasis are unclear. We show that this communication occurs via sphingosine 1-phosphate (S1P) generated systemically by sphingosine kinase 1 (SK1), rather than via tumour-derived S1P. Modulation of systemic, but not tumour SK1, prevented S1P elevation, and inhibited TRAMP-induced prostate cancer growth in TRAMP(+/+) SK1(-/-) mice, or lung metastasis of multiple cancer cells in SK1(-/-) animals. Genetic loss of SK1 activated a master metastasis suppressor, Brms1 (breast carcinoma metastasis suppressor 1), via modulation of S1P receptor 2 (S1PR2) in cancer cells. Alterations of S1PR2 using pharmacologic and genetic tools enhanced Brms1. Moreover, Brms1 in S1PR2(-/-) MEFs was modulated by serum S1P alterations. Accordingly, ectopic Brms1 in MB49 bladder cancer cells suppressed lung metastasis, and stable knockdown of Brms1 prevented this process. Importantly, inhibition of systemic S1P signalling using a novel anti-S1P monoclonal antibody (mAb), Sphingomab, attenuated lung metastasis, which was prevented by Brms1 knockdown in MB49 cells. Thus, these data suggest that systemic SK1/S1P regulates metastatic potential via regulation of tumour S1PR2/Brms1 axis.

Topics: Animals; Disease Models, Animal; Humans; Lung Neoplasms; Lysophospholipids; Male; Mice; Mice, Knockout; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor); Prostatic Neoplasms; Receptors, Lysosphingolipid; Repressor Proteins; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; Urinary Bladder Neoplasms

Sphingosine-1-phosphate (SPP) induces a variety of cellular responses, including Ca2+ signaling, proliferation, and inhibition of motility, apparently by acting at specific G protein coupled receptors. Here, the expression, signaling, and motile responses of sphingolipid receptors were examined in human bladder carcinoma (J82) cells, for which lysophosphatidic acid (LPA) and thrombin act as potent agonists. SPP potently and rapidly mobilized Ca2+, stimulated phospholipases C and D, and inhibited cAMP accumulation, without affecting growth of J82 cells, which express the recently identified SPP receptors, Edg-1 and Edg-3. The effects of SPP were mimicked by sphingosylphosphorylcholine (SPPC) and strongly attenuated by pertussis toxin (PTX). SPP and SPPC by themselves induced a small, PTX-sensitive motile response. However, stimulation of cell motility by LPA, which by itself was also PTX-sensitive, was blocked by SPP and SPPC. In contrast, motility stimulation by thrombin, which by itself was PTX-insensitive, was strongly augmented by the sphingolipids in a PTX-sensitive manner. The bidirectional regulation of LPA- and thrombin-stimulated motility was not due to selective alterations in the activation of Rho GTPases which control cell motility. In fact, RhoA activation and Rho-dependent actin stress fiber formation induced by LPA and thrombin were mimicked, but not altered by SPP and SPPC. We conclude that J82 cells express sphingolipid receptors, coupled via G proteins to several signaling pathways. Most importantly, these sphingolipid receptors potently regulate thrombin- and LPA-stimulated motility, but in opposite directions, suggesting that migration of these human bladder carcinoma cells is controlled by a complex network of interacting extracellular ligands.

Topics: Actins; Calcium; Carcinoma; Cell Division; Cell Movement; Cyclic AMP; GTP-Binding Proteins; Humans; Lysophospholipids; Phospholipase D; Phosphorylcholine; Receptors, Cell Surface; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Sphingolipids; Sphingosine; Thrombin; Tumor Cells, Cultured; Type C Phospholipases; Urinary Bladder Neoplasms