sphingosine-kinase and Neoplasm-Metastasis

The development of chemotherapeutic resistance is a major challenge in oncology. Elevated sphingosine kinase 1 (SK1) levels is predictive of a poor prognosis, and SK1 overexpression may confer resistance to chemotherapeutics. The SK/sphingosine-1-phosphate (S1P)/sphingosine-1-phosphate receptor (S1PR) signaling pathway has been implicated in the progression of various cancers and in chemotherapeutic drug resistance. Therefore, SK1 may represent an important target for cancer therapy. Targeting the SK/S1P/S1PR signaling pathway may be an effective anticancer therapeutic strategy, particularly in the context of overcoming drug resistance. This review summarizes our current understanding of the role of SK/S1P/S1PR signaling in cancer and development of SK1 inhibitors.

Topics: Animals; Antineoplastic Agents; Apoptosis; Drug Resistance, Neoplasm; Enzyme Inhibitors; Humans; Lysophospholipids; Molecular Targeted Therapy; Neoplasm Metastasis; Neoplasms; Phosphotransferases (Alcohol Group Acceptor); Receptors, Lysosphingolipid; Signal Transduction; Sphingosine

There is considerable evidence that sphingosine kinases play a key role in cancer progression, which might involve positive selection of cancer cells that have been provided with a survival and growth advantage as a consequence of overexpression of the enzyme. Therefore, inhibitors of sphingosine kinase represent a novel class of compounds that have potential as anticancer agents. Poor inhibitor potency is a major issue that has precluded successful translation of these compounds into the clinic. However, recent discoveries have shown that sphingosine kinase 1 is an allosteric enzyme and that some inhibitors offer improved effectiveness by inducing proteasomal degradation of the enzyme or having nanomolar potency. Herein, we provide a perspective about these recent developments and highlight the importance of translating basic pharmacologic and biochemical findings on sphingosine kinase into new drug discovery programs for treatment of cancer.

Topics: Allosteric Regulation; Animals; Antineoplastic Agents; Cell Division; Dose-Response Relationship, Drug; Drug Design; Drug Screening Assays, Antitumor; Fingolimod Hydrochloride; Humans; Lysophospholipids; Mice; Molecular Targeted Therapy; Neoplasm Metastasis; Neoplasm Proteins; Neoplasms; Organophosphonates; Phosphotransferases (Alcohol Group Acceptor); Propylene Glycols; Proteasome Endopeptidase Complex; Protein Kinase Inhibitors; Sphingosine; Vinyl Compounds

Long non-coding RNAs (lncRNAs) are closely associated with the development of lung adenocarcinoma (LADC). The present study focused on the role of LINC00960 in LADC. miRNA and mRNA expression levels were detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cellular functions were evaluated by MTT, colony formation, and Transwell assays, respectively. LINC00960 Luciferase and RNA pull-down assays were performed to clarify the interaction between miR-124a and LINC00960 or Recombinant Sphingosine Kinase 1 (SphK1). We observed that LINC00960 was overexpressed in LADC tumor tissues and cell lines. LINC00960 knockdown suppressed the proliferation, migration, and invasion of LADC cells. Moreover, LINC00960 sponged miR-124a to inhibit the SphK1/S1P pathway in LADC cells. LINC00960 knockdown markedly reduced the rate of tumor growth. The luciferase reporter assay results demonstrated an interaction between miR-124a and LINC00960 or SphK1. This interaction was confirmed using the RNA pull-down assay. In addition, miR-124a downregulation or SphK1 upregulation reversed the inhibitory effects of LINC00960 knockdown on cellular functions of LADC cells, suggesting that LINC00960 may be a potential therapeutic biomarker for LADC via the miR-124a/SphK1 axis. Accordingly, LINC00960 may be a potential therapeutic biomarker for LADC.

Topics: A549 Cells; Adenocarcinoma of Lung; Animals; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lung Neoplasms; Male; Mice; MicroRNAs; Neoplasm Metastasis; Neoplasm Transplantation; Phosphotransferases (Alcohol Group Acceptor); RNA, Long Noncoding; Up-Regulation

It was demonstrated that Sphingosine kinase 1 (SphK1) promotes tumor progression and confers the malignancy phenotype of colorectal cancer by activating the focal adhesion kinase (FAK) pathway. However, further clarification is required to determine if SphK1 promotes the metastasis of colorectal cancer by inducing epithelial‑mesenchymal transition (EMT), and its mechanisms have not been fully elucidated. Immunohistochemistry staining was used to detect protein expression in normal colonic mucosa tissues and colorectal cancer tissues. Cells were transfected to overexpress SphK1, downregulate SphK1 or downregulate FAK. An MTT assay was used to detect the drug toxicity to cells. Transwell and wound healing assays were used to detect cell migration ability. Reverse transcription‑polymerase chain reaction and western blot analysis were used to detect the expression of mRNA and protein, respectively. Scanning electron microscopy was used to observe the microvilli and pseudopodia of the cells. The analysis of protein expression in 114 human colorectal cancer tissues demonstrated that the expressions of SphK1, FAK, phosphorylated (p)‑FAK, E‑cadherin and vimentin were associated with the metastasis of colorectal cancer. Furthermore, the patients with colorectal cancer with SphK1‑positive cancer demonstrated poorer prognosis compared with SphK1‑negative cancer. FAK knockdown and SphK1 knockdown of human colon cancer RKO cells inhibited the EMT and migrational potency, along with the expression of p‑FAK, p‑protein kinase B (AKT) and matrix metalloproteinase (MMP)2/9. In contrast, SphK1 overexpression promoted EMT, migrational potency, and the expression of p‑FAK, p‑AKT and MMP2/9 in HT29 cells. Additionally, the EMT and migrational potency of SphK1‑overexpressing HT29 cells was suppressed by a FAK inhibitor, and the expression of p‑FAK, p‑AKT and MMP2/9 was suppressed by blocking the FAK pathway. In conclusion, SphK1 promoted the migration and metastasis of colon cancer by inducing EMT mediated by the FAK/AKT/MMPs axis.

Topics: Adult; Aged; Aged, 80 and over; Cell Line, Tumor; Colorectal Neoplasms; Epithelial-Mesenchymal Transition; Female; Focal Adhesion Protein-Tyrosine Kinases; HT29 Cells; Humans; Male; Matrix Metalloproteinases; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Phosphotransferases (Alcohol Group Acceptor); Proto-Oncogene Proteins c-akt; Signal Transduction; Survival Analysis

Sphingosine kinase 1 (SPHK1) is up-regulated in many different cancers and plays a crucial role in tumor development and progression. However, the prognostic value of SPHK1 in colorectal cancer (CRC) remains unclear.. The expression of SPHK1 in CRC cell lines and 328 CRC tissue samples was examined. It was also investigated whether SPHK1 expression is associated with clinicopathological characteristics and outcomes in patients with CRC.. HCT 116 and HT-29 cells expressed significantly higher SPHK1 levels than did CCD 841 CoTr. On immunohistochemistry, SPHK1 expression was significantly higher in CRC tissue than in normal colonic mucosal tissue, with 34.1% of CRC patients exhibiting high SPHK1 expression. High SPHK1 expression in CRC was significantly associated with higher histological grade, deeper invasion depth, lymphatic invasion, vascular invasion, and development of distant metastasis, and was shown to be an independent predictor of distant metastasis. Furthermore, patients with high SPHK1 expression had significantly lower overall survival rates than those with low expression.. High SPHK1 expression was significantly associated with aggressive CRC behavior and worse overall survival, and was an independent predictor of distant metastasis. SPHK1 may thus be a potential prognostic biomarker and therapeutic target in CRC patients.

Topics: Aged; Biomarkers, Tumor; Cell Line, Tumor; Colorectal Neoplasms; Disease Progression; Female; HCT116 Cells; HT29 Cells; Humans; Immunohistochemistry; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor); Prognosis; Treatment Outcome

Gram-negative bacteria have been found to be a major population in prostatitis and prostate cancer (PCa) tissues. Lipopolysaccharide (LPS), a major compound of Gram-negative bacteria, with stimulatory activities in some cancer types, but has not been fully studied in PCa. In this study, we examined the effect of LPS on the invasion of PCa cells. Interestingly, LPS can enhance the invasiveness of PCa, but had no significant effect on PCa cell viability. Using protease inhibitor screening and biochemical analyses, matriptase, a member of the membrane-anchored serine protease family, is found to play a key role in LPS-induced PCa cell invasion. Mechanistically, Toll-like receptor 4 (TLR4, LPS receptor)-sphingosine kinase 1 (SphK1) signaling underlies LPS-induced matriptase activation and PCa cell invasion. Specifically, LPS induced the S225 phosphorylation of SphK1 and the translocation of SphK1 to plasma membrane, leading to the production of sphingosine 1-phosphate (S1P), ERK1/2 and matriptase activation via S1P receptor 4 (S1PR4). This phenomenon is further validated using the patient-derived explant (PDE) model. Indeed, there is a significant correlation among the elevated SphK1 levels, the Gleason grades of PCa specimens, and the poor survival of PCa patients. Taken together, this study demonstrates a potential impact of LPS on PCa progression. Our results provide not only a new finding of the role of bacterial infection in PCa progression but also potential therapeutic target(s) associated with PCa metastasis.

Topics: Adaptor Proteins, Signal Transducing; Disease Progression; Enzyme Activation; Humans; Male; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor); Polysaccharides; Prostatic Neoplasms; Serine Endopeptidases; Sphingosine-1-Phosphate Receptors

BACKGROUND Triple negative breast cancer (TNBC) has a more aggressive recurrence. Previous reports have demonstrated that sphingosine kinase 1 (SphK1) is a crucial regulator of breast cancer progression. However, the correlation of SphK1 with clinical prognosis has been poorly investigated. Thus, we aimed to elaborate the role of SphK1 in TNBC metastasis. MATERIAL AND METHODS We first determined the level of SphK1 in breast cancer tissue samples and breast cancer cells. Furthermore, the expression of HER2 and phosphor-SphK1 (pSphK1) in human breast cancer tissue samples was determined by immunohistochemical analysis. Associations between SphK1 and clinical parameters of tumors were analyzed. The activity of SphK1 was measured by fluorescence analysis. Extracellular sphingosine-1-phosphate (S1P) was detected using an ELISA kit. Associations between SphK1 and metastasis potential were analyzed by Transwell assay. RESULTS Levels of SphK1 in TNBC patients were significantly higher than levels in other patients with other breast tumors. The expression of SphK1 was positively correlated with poor overall survival (OS) and progression-free survival (PFS), as well as poor response to 5-FU and doxorubicin. The depression of SphK1 thus could repress the Notch signaling pathway, reduce migration, and invasion of TNBC cells in vivo and in vitro. Furthermore, silencing of SphK1 by Ad-SPHK1-siRNA or SphK1 inhibitor PF543 sensitized TNBCs to 5-FU and doxorubicin. Our results also indicated that SphK1 inhibition could effectively counteracts tumors metastasis via Notch signaling pathways, indicating a potentially anti-tumor strategy in TNBC. CONCLUSIONS We found that elevated levels of pSphK1 were positive correlation with high expression of S1P, which in turn promoted metastasis of TNBC through S1P/S1PR3/Notch signaling pathway.

Topics: Animals; Cell Line, Tumor; Doxorubicin; Drug Synergism; Female; Fluorouracil; Heterografts; Humans; Lysophospholipids; MCF-7 Cells; Methanol; Mice; Mice, Inbred NOD; Mice, SCID; Middle Aged; Neoplasm Metastasis; Neoplasm Recurrence, Local; Phosphotransferases (Alcohol Group Acceptor); Pyrrolidines; Receptor, ErbB-2; Receptors, Lysosphingolipid; Receptors, Notch; Signal Transduction; Sphingosine; Sphingosine-1-Phosphate Receptors; Sulfones; Triple Negative Breast Neoplasms; Up-Regulation

About 40,000 American women die from metastatic breast cancer each year despite advancements in treatment. Approximately, 15% of breast cancers are triple-negative for estrogen receptor, progesterone receptor, and HER2. Triple-negative cancer is characterized by more aggressive, harder to treat with conventional approaches and having a greater possibility of recurrence. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid signaling mediator has emerged as a key regulatory molecule in breast cancer progression. Therefore, we investigated whether cytosolic sphingosine kinase type 1 (SphK1) and nuclear sphingosine kinase type 2 (SphK2), the enzymes that make S1P are critical for growth and PI3K/AKT, ERK-MAP kinase mediated survival signaling of lung metastatic variant LM2-4 breast cancer cells, generated from the parental triple-negative MDA-MB-231 human breast cancer cell line. Similar with previous report, SphKs/S1P signaling is critical for the growth and survival of estrogen receptor positive MCF-7 human breast cancer cells, was used as our study control. MDA-MB-231 did not show a significant effect of SphKs/S1P signaling on AKT, ERK, and p38 pathways. In contrast, LM2-4 cells that gained lung metastatic phenotype from primary MDA-MB-231 cells show a significant effect of SphKs/S1P signaling requirement on cell growth, survival, and cell motility. PF-543, a selective potent inhibitor of SphK1, attenuated epidermal growth factor (EGF)-mediated cell growth and survival signaling through inhibition of AKT, ERK, and p38 MAP kinase pathways mainly in LM2-4 cells but not in parental MDA-MB-231 human breast cancer cells. Moreover, K-145, a selective inhibitor of SphK2, markedly attenuated EGF-mediated cell growth and survival of LM2-4 cells. We believe this study highlights the importance of SphKs/S1P signaling in metastatic triple-negative breast cancers and targeted therapies.

Topics: Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Down-Regulation; Epidermal Growth Factor; Female; Humans; Lysophospholipids; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; RNA, Small Interfering; Signal Transduction; Sphingosine; Triple Negative Breast Neoplasms

Dynamic interaction between cancer cells and the surrounding microenvironment is critical for cancer progression via changes in cellular behavior including alteration of secreted molecules. However, the molecular mechanisms underlying the influence exerted by the cancer microenvironment on secretion of molecules during cancer progression remain largely unknown. In this study, we report that secretion of spingsine-1-phosphate (S1P) and its regulator, SphK1 expression is dependent of the substrate rigidity, which is critical for the balance between cancer cell invasion and adhesion. Conditioned media (CM) of MDA-MB-231, an aggressive breast cancer cell obtained from soft substrate (~0.5 kPa) induced chemo-attractive invasion, while CM obtained from stiff substrate (~2.5 kPa) increased cell adhesion instead. We found that the expression of SphK1 is upregulated in the stiff substrate, resulting in an increase in S1P levels in the CM. We also found that upregulation of SphK1 expression in the stiff substrate is dominant in metastatic cancer cells but not in primary cancer cells. These results suggest that alterations in the mechanical environment of the ECM surrounding the tumor cells actively regulate cellular properties such as secretion, which in turn, may contribute to cancer progression.

Topics: Biomechanical Phenomena; Breast Neoplasms; Cell Adhesion; Cell Line, Tumor; Culture Media, Conditioned; Extracellular Matrix; Female; Humans; Lysophospholipids; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor); Sphingosine; Tumor Microenvironment

VEGFR2 tyrosine kinase inhibition (TKI) is a valuable treatment approach for patients with metastatic renal cell carcinoma (RCC). However, resistance to treatment is inevitable. Identification of novel targets could lead to better treatment for patients with TKI-naïve or -resistant RCC.. In this study, we performed transcriptome analysis of VEGFR TKI-resistant tumors in a murine model and discovered that the SPHK-S1P pathway is upregulated at the time of resistance. We tested sphingosine-1-phosphate (S1P) pathway inhibition using an anti-S1P mAb (sphingomab), in two mouse xenograft models of RCC, and assessed tumor SPHK expression and S1P plasma levels in patients with metastatic RCC.. Resistant tumors expressed several hypoxia-regulated genes. The SPHK1 pathway was among the most highly upregulated pathways that accompanied resistance to VEGFR TKI therapy. SPHK1 was expressed in human RCC, and the product of SPHK1 activity, S1P, was elevated in patients with metastatic RCC, suggesting that human RCC behavior could, in part, be due to overproduction of S1P. Sphingomab neutralization of extracellular S1P slowed tumor growth in both mouse models. Mice bearing tumors that had developed resistance to sunitinib treatment also exhibited tumor growth suppression with sphingomab. Sphingomab treatment led to a reduction in tumor blood flow as measured by MRI.. Our findings suggest that S1P inhibition may be a novel therapeutic strategy in patients with treatment-naïve RCC and also in the setting of resistance to VEGFR TKI therapy.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Agents; Cell Line, Tumor; Cluster Analysis; Disease Models, Animal; Drug Resistance, Neoplasm; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; Humans; Kidney Neoplasms; Lysophospholipids; Mice; Neoplasm Metastasis; Neovascularization, Pathologic; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Receptors, Vascular Endothelial Growth Factor; Sphingosine; Transcriptome; Tumor Burden; Up-Regulation; Xenograft Model Antitumor Assays

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

We have previously reported that, in prostate cancer, inhibition of the oncogenic sphingosine kinase-1/sphingosine 1-phosphate (SphK1/S1P) pathway is a key element in chemotherapy-induced apoptosis. Here, we show that selective pharmacologic inhibition of SphK1 triggers apoptosis in LNCaP and PC-3 prostate cancer cells, an effect that is reversed by SphK1 enforced expression. More importantly, we show for the first time that the up-regulation of the SphK1/S1P pathway plays a crucial role in the resistance of prostate cancer cells to chemotherapy. Importantly, pharmacologic SphK1 inhibition with the B-5354c compound sensitizes LNCaP and PC-3 cells to docetaxel and camptothecin, respectively. In vivo, camptothecin and B-5354c alone display a limited effect on tumor growth in PC-3 cells, whereas in combination there is a synergy of effect on tumor size with a significant increase in the ceramide to S1P sphingolipid ratio. To conclude, our study highlights the notion that drugs specifically designed to inhibit SphK1 could provide a means of enhancing the effects of conventional treatment through the prosurvival antiapoptotic SphK1/S1P pathway.

Topics: 4-Aminobenzoic Acid; Animals; Antineoplastic Agents; Apoptosis; Camptothecin; Caspases; Cell Line, Tumor; Cell Survival; Ceramides; Drug Therapy, Combination; Green Fluorescent Proteins; Humans; Irinotecan; Lysophospholipids; Male; Mice; Neoplasm Metastasis; para-Aminobenzoates; Phosphotransferases (Alcohol Group Acceptor); Prostatic Neoplasms; Sphingosine; Treatment Outcome; Xenograft Model Antitumor Assays

Sphingosine-1-phosphate (S1P) is a potent lysolipid involved in a variety of biological responses important for cancer progression. Therefore, we investigated the role of sphingosine kinase type 1 (SphK1), the enzyme that makes S1P, in the motility, growth, and chemoresistance of MCF-7 breast cancer cells. Epidermal growth factor (EGF), an important growth factor for breast cancer progression, activated and translocated SphK1 to plasma membrane. SphK1 was required for EGF-directed motility. Downregulation of SphK1 in MCF-7 cells reduced EGF- and serum-stimulated growth and enhanced sensitivity to doxorubicin, a potent chemotherapeutic agent. These results suggest that SphK1 may be critical for growth, metastasis and chemoresistance of human breast cancers.

Topics: Apoptosis; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Enzyme Activation; Humans; Neoplasm Metastasis; Phosphotransferases (Alcohol Group Acceptor)