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Objective:To determine lysophosphatidic acid receptor 6 (LPAR6) expression in patients with mycosis fungoides (MF) , a variant of cutaneous T-cell lymphoma (CTCL) , and to investigate its role and mechanism of action in the development and prognosis of CTCL.Methods:A total of 110 patients with confirmed MF were collected from Department of Dermatology, Peking University First Hospital from 2011 to 2020, including 24 with large-cell transformation (LCT) and 25 with non-large cell transformation (NLCT) in the discovery cohort, and 24 with LCT and 37 with NLCT in the validation cohort. RNA sequencing and RT-PCR were conducted to determine the LPAR6 expression in patients in the discovery cohort and validation cohort respectively. LPAR6 expression was compared between patients with LCT and those with NLCT, and its effect on the prognosis of patients was evaluated. Two LPAR6-overexpressing CTCL cell lines MyLa and Sz4 were constructed to evaluate the effect of LPAR6 overexpression on proliferative activity of MyLa and Sz4 cells, with the cells normally expressing LPAR6 as the control group; after the treatment with LPAR6-related ligand lysophosphatidic acid (LPA) , 2S-OMPT, adenosine triphosphate (ATP) or adenosine (ADO) , the effects of LPAR6 activation on the proliferative activity and apoptosis of LPAR6-overexpressing MyLa and Sz4 cells were evaluated by the MTS method and flow cytometry respectively. Log-rank test was used for prognostic analysis, and t test or Mann-Whitney U test was used for comparisons between two groups. Results:As RNA sequencing showed, LPAR6 was one of the significantly underexpressed genes in the LCT group in the discovery cohort; in the validation cohort, LPAR6 expression (median[ Q1, Q3]) was significantly lower in the LCT group (204.90[81.90, 512.70]) than in the NLCT group (809.40[417.50, 1 829.20], U= 242.00, P= 0.002) ; in the two cohorts, the underexpression of LPAR6 was significantly associated with increased risk of poor prognosis (both P < 0.01) . Cell proliferation assay showed no significant difference in the proliferative activity of MyLa or Sz4 cells between the LPAR6 overexpression group and control group at 0, 24, 48 and 72 hours during the experiment (all P > 0.05) ; 48 hours after activation of LPAR6 by LPA, 2S-OMPT, ATP and ADO in MyLa cells, the LPAR6 overexpression group showed significantly decreased cellular proliferative activity (1.38 ± 0.01, 1.04 ± 0.01, 1.09 ± 0.03, 1.23 ± 0.01, respectively) compared the control group (1.73 ± 0.04, 1.23 ± 0.01, 1.24 ± 0.01, 1.42 ± 0.03, t= 30.33, 18.38, 4.78, 5.75, respectively, all P < 0.05) , but significantly increased cell apoptosis rate (17.93% ± 0.88%, 17.75% ± 0.35%, 23.97% ± 0.57%, 31.44% ± 0.34%, respectively) compared the control group (3.98% ± 0.03%, 7.81% ± 0.59%, 11.95% ± 0.85%, 12.02% ± 0.48%, t= 15.93, 14.49, 11.74, 33.01, respectively, all P < 0.05) ; 48 hours after activation of LPAR6 by 2S-OMPT and ADO in Sz4 cells, compared with the control group, the LPAR6 overexpression group also showed significantly decreased cellular proliferative activity (2S-OMPT: 1.29 ± 0.04 vs. 1.48 ± 0.01; ADO: 1.27 ± 0.01 vs. 1.51 ± 0.02; both P < 0.05) , but significantly increased cell apoptosis rate (2S-OMPT: 41.70% ± 0.70% vs. 29.35% ± 0.55%; ADO: 37.05% ± 0.15% vs. 24.60% ± 1.00%; both P < 0.05) . Conclusions:LPAR6 was underexpressed in the patients with LCT, and its underexpression was significantly associated with increased risk of poor prognosis. In vitro activation of LPAR6 could inhibit the proliferation of CTCL cells and promote their apoptosis, suggesting that the decrease of LPAR6 expression may be one of the important mechanisms underlying disease progression in patients with LCT.
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Objective@#To investigate the expression and clinical significance of lysophosphatidic acid receptor 5 (LPA5) protein in breast cancer tissues.@*Methods@#The specimens of breast cancer tissues and adjacent tissues of 80 breast cancer patients from January 2015 to December 2016 in the First People's Hospital of Yongkang were selected in the study.The expression of LPA5 in breast cancer tissues and adjacent tissues was determined by immunohistochemistry.The clinical case characteristics of patients were collected.@*Results@#The positive expression rate of LPA5 in breast cancer tissues(72.5%) was higher than that in adjacent tissues(8.75%)(χ2=67.394, P<0.05). The positive rate of LPA5 in clinical stage Ⅲ-Ⅳ(91.3%) was higher than that in stage Ⅰ-Ⅱ(64.9%)(χ2=5.725, P<0.05). The positive rate of LPA5 in patients with lymph node metastasis(94.7%) was higher than that in patients without lymph node metastasis(52.4%)(χ2=17.951, P<0.05). The positive rate of LPA5 in patients with intravascular tumor thrombus(92.3%) was higher than that in patients without intravascular tumor thrombus (63.3%)(χ2=7.580, P<0.05). The expression of LPA5 in breast cancer tissues was not related to age and tumor diameter (P>0.05). There were no significant differences in the positive expression rates of LPA5 in the breast cancer tissues among luminal type, human epidermal growth factor receptor 2 (Her2) overexpressing type and triple negative type (P>0.05). The disease-free survival rate(86.3%) and overall survival rate(87.5%) of patients with negative expression of LPA5 in breast cancer tissues were higher than those in breast cancer tissues with positive expression (65.0%, 66.3%)(χ2=4.517, 4.328, all P<0.05).@*Conclusion@#LPA5 expression is up-regulated in breast cancer tissues, and LPA5 may be involved in the development and progression of breast cancer, which is closely related to the prognosis of breast cancer.
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Objective To investigate the expression and clinical significance of lysophosphatidic acid receptor 5 (LPA5) protein in breast cancer tissues.Methods The specimens of breast cancer tissues and adjacent tissues of 80 breast cancer patients from January 2015 to December 2016 in the First People's Hospital of Yongkang were selected in the study.The expression of LPA5 in breast cancer tissues and adjacent tissues was determined by immunohisto-chemistry.The clinical case characteristics of patients were collected.Results The positive expression rate of LPA5 in breast cancer tissues (72.5%) was higher than that in adjacent tissues (8.75%) (χ2 ＝67.394,P＜0.05).The positive rate of LPA5 in clinical stage Ⅲ-Ⅳ(91.3%) was higher than that in stage Ⅰ-Ⅱ(64.9%)(χ2 ＝5.725, P＜0.05).The positive rate of LPA5 in patients with lymph node metastasis (94.7%) was higher than that in patients without lymph node metastasis (52.4%)(χ2 ＝17.951,P＜0.05).The positive rate of LPA5 in patients with intravascular tumor thrombus ( 92.3%) was higher than that in patients without intravascular tumor thrombus (63.3%)(χ2 ＝7.580,P＜0.05).The expression of LPA5 in breast cancer tissues was not related to age and tumor diameter (P＞0.05).There were no significant differences in the positive expression rates of LPA 5 in the breast cancer tissues among luminal type ,human epidermal growth factor receptor 2 (Her2) overexpressing type and triple negative type (P＞0.05).The disease-free survival rate(86.3%) and overall survival rate (87.5%) of patients with negative expression of LPA5 in breast cancer tissues were higher than those in breast cancer tissues with positive expression (65.0%,66.3%)(χ2 ＝4.517,4.328,all P＜0.05).Conclusion LPA5 expression is up-regulated in breast cancer tissues,and LPA5 may be involved in the development and progression of breast cancer ,which is closely related to the prognosis of breast cancer.
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Objectives To investigate the effects of plasma from the patients with preeclampsia on proliferation and apoptosis of human umbilical vein endothelial cells(HUVEC),and to explore the relationship between cell damage and lysophosphatidic acid(LPA)receptors.Methods Sixty patients with preeclampsia were recruited from October 2011 to June 2012 in the First Affilated Hospital of Zhengzhou University.Among them,thirty cases were defined as the mild preeclampsia group and thirty cases were defined as the severe preeclampsia group.The other thirty healthy pregnant women were recruited in the healthy pregnant women group.The levels of plasma LPA in the three groups were measured.The HUVEC were cultured in vitro with plasma from the three groups,and a blank control group was set up as well.Proliferation and apoptosis of HUVEC were measured by MTT assay and flow cytometry.Immunohistochemistry of biotin streptomyces protein peroxidase(SP)method was used to measure the protein expression level of Edg 2,4,7.Results(1)The plasma LPA levels in the healthy pregnant woman group,mild preeclampsia group and severe preeclampsia group were(3.38 ± 2.08)μmol/L,(6.12 ± 0.22)μmol/L,(9.10 ± 0.17)μmol/L,respectively.The plasma levels of LPA in patients with preeclampsia were significantly higher than that in the healthy pregnant women(P ＜ 0.01).(2)The proliferation rate of HUVEC in the mild and severe preeclampsia groups [(65.2 ± 2.7)％ and(51.9 ± 2.8)％] were significantly lower than that in the healthy pregnant women group and the control group [(84.3 ± 3.1)％ and(100.0 ± 0.0)％,P ＜ 0.01].(3)The early apoptosis rate,middle-late apoptosis rate and total apoptosis rate of HUVEC in the mild and severe preeclampsia groups [total apoptosis rate were(30.4 ±2.0)％ and(43.4 ±2.5)％] were significantly higher than those in the healthy pregnant women group and the control group [total apoptosis rate were(18.6 ± 1.6)％ and(8.0 ± 1.5)％,P ＜ 0.01].(4)The expression positive rates of Edg 2,4,7 proteins in the four groups were as following:mild preeclampsia group 83％,80％ and 73％;severe preeclampsia group 97％,93％ and 90％;healthy pregnant women group 40％,40％ and 37％,and the control group 10％,10％ and 7％ respectively.The positive rates of HUVEC in the mild and severe preeclampsia groups were significantly higher than those in the healthy pregnant women group and the control group(P ＜ 0.01).Conclusions The plasma of patients with preeclampsia could inhibit proliferation and promote apoptosis of HUVEC,and induce the expression of Edg 2,4,7 proteins.It suggested that the increase of lysophosphatidic acid in plasma could be one of the reasons of endothelial cell damage in patients with preeclampsia.
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Hepatocellular carcinoma is the fifth most common malignant cancer worldwide with a continuously increasing incidence annually,highly malignant degree and poor prognosis.There is few effective treatment for hepatocellular carcinoma at present,based on the principle of surgical resection and chemotherapy.The present study showed that lysophosphatidic acid is highly expressed in tumor tissue,bile and serum in the patient with hepatocellular carcinoma.It plays an important role in hepatocellular carcinoma migration,invasion and tumor growth.Therefore,the mechanism which lysophosphatidic promots hepatocellular carcinoma is reviened as fellow.
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Lysophosphatidic acid (LPA) stimulates growth and invasion of ovarian cancer cells and tumor angiogenesis. Cancer-derived LPA induces differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs) to alpha-smooth muscle actin (alpha-SMA)-positive cancer-associated fibroblasts. Presently, we explored whether cancer-derived LPA regulates secretion of pro-angiogenic factors from hASCs. Conditioned medium (CM) from the OVCAR-3 and SKOV3 ovarian cancer cell lines stimulated secretion angiogenic factors such as stromal-derived factor-1alpha (SDF-1alpha) and VEGF from hASCs. Pretreatment with the LPA receptor inhibitor Ki16425 or short hairpin RNA lentiviral silencing of the LPA1 receptor abrogated the cancer CM-stimulated expression of alpha-SMA, SDF-1, and VEGF from hASCs. LPA induced expression of myocardin and myocardin-related transcription factor-A, transcription factors involved in smooth muscle differentiation, in hASCs. siRNA-mediated depletion of endogenous myocardin and MRTF-A abrogated the expression of alpha-SMA, but not SDF-1 and VEGF. LPA activated RhoA in hASCs and pretreatment with the Rho kinase inhibitor Y27632 completely abrogated the LPA-induced expression of alpha-SMA, SDF-1, and VEGF in hASCs. Moreover, LPA-induced alpha-SMA expression was abrogated by treatment with the ERK inhibitor U0126 or the phosphoinositide-3-kinase inhibitor LY294002, but not the PLC inhibitor U73122. LPA-induced VEGF secretion was inhibited by LY294002, whereas LPA-induced SDF-1 secretion was markedly attenuated by U0126, U73122, and LY294002. These results suggest that cancer-secreted LPA induces differentiation of hASCs to cancer-associated fibroblasts through multiple signaling pathways involving Rho kinase, ERK, PLC, and phosphoinositide-3-kinase.
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Lysophosphatidic acid (LPA) is a bioactive phospholipids and involves in various cellular events, including tumor cell migration. In the present study, we investigated LPA receptor and its transactivation to EGFR for cyclooxygenase-2 (COX-2) expression and cell migration in CAOV-3 ovarian cancer cells. LPA induced COX-2 expression in a dose-dependent manner, and pretreatment of the cells with pharmacological inhibitors of Gi (pertussis toxin), Src (PP2), EGF receptor (EGFR) (AG1478), ERK (PD98059) significantly inhibited LPA- induced COX-2 expression. Consistent to these results, transfection of the cells with selective Src siRNA attenuated COX-2 expression by LPA. LPA stimulated CAOV-3 cell migration that was abrogated by pharmacological inhibitors and antibody of EP2. Higher expression of LPA2 mRNA was observed in CAOV-3 cells, and transfection of the cells with a selective LPA2 siRNA significantly inhibited LPA-induced activation of EGFR and ERK, as well as COX-2 expression. Importantly, LPA2 siRNA also blocked LPA-induced ovarian cancer cell migration. Collectively, our results clearly show the significance of LPA2 and Gi/Src pathway for LPA-induced COX-2 expression and cell migration that could be a promising drug target for ovarian cancer cell metastasis.