Malignant peritoneal mesothelioma(PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be sugg...Malignant peritoneal mesothelioma(PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction(CRS) with hyperthermic intraperitoneal chemotherapy(HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Ac-cordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1(SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.展开更多
Circulation of mature lymphocytes between blood and secondary lymphoid tissues plays a central role in the immune system. Homing of lymphocytes from blood into secondary lymphoid tissues beyond high endothelial venule...Circulation of mature lymphocytes between blood and secondary lymphoid tissues plays a central role in the immune system. Homing of lymphocytes from blood into secondary lymphoid tissues beyond high endothelial venules is highly dependent on the interaction between the chemokines CCL19, CCL21, CXCL12, and CXCL13, and their receptors CCR7, CXCR4 and CXCR5. However, the molecular mechanism（s） of lymphocyte egress from secondary lymphoid tissues to lymph remained unclear. We have found a new class of immunomodulator, FTY720 by chemical modification of vegetative wasp-derived natural product, ISP-I （myriocin）. FTY720 has been shown to be highly effective in experimental allograft and autoimmune disease models. A striking feature of FTY720 is the induction of a marked decrease in peripheral blood lymphocytes at doses that show immunomodulating activity in these models. The reduction of circulating lymphocytes by FTY720 is caused by sequestration of lymphocytes into secondary lymphoid tissues and thymus. FTY720 is rapidly converted to （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] by sphingosine kinase 2 in vivo. （S）-FTY720-P acting as a potent agonist of S1P receptor type 1 （S1P1）, induces long-term down-regulation of S1P1 on lymphocytes, and thereby inhibits the migration of lymphocytes toward S1P. Thus, it is presumed that FTY720-induced lymphocyte sequestration is due to the inhibition of S1P/S1P1-dependent lymphocyte egress from secondary lymphoid tissues and thymus by its active metabolite （S）-FTY720-P. Throughout the analysis of the mechanism of action of FTY720, it is clarified that S1P/S1P1 interaction plays an important role for lymphocyte egress from secondary lymphoid tissues and thymus.展开更多
基金Supported by United States National Institute of Health(to Kazuaki Takabe),No.R01CA160688Investigator Initiated Research Grant(to Susan G Komen),No.IIR12222224
文摘Malignant peritoneal mesothelioma(PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction(CRS) with hyperthermic intraperitoneal chemotherapy(HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Ac-cordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1(SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.
文摘Circulation of mature lymphocytes between blood and secondary lymphoid tissues plays a central role in the immune system. Homing of lymphocytes from blood into secondary lymphoid tissues beyond high endothelial venules is highly dependent on the interaction between the chemokines CCL19, CCL21, CXCL12, and CXCL13, and their receptors CCR7, CXCR4 and CXCR5. However, the molecular mechanism（s） of lymphocyte egress from secondary lymphoid tissues to lymph remained unclear. We have found a new class of immunomodulator, FTY720 by chemical modification of vegetative wasp-derived natural product, ISP-I （myriocin）. FTY720 has been shown to be highly effective in experimental allograft and autoimmune disease models. A striking feature of FTY720 is the induction of a marked decrease in peripheral blood lymphocytes at doses that show immunomodulating activity in these models. The reduction of circulating lymphocytes by FTY720 is caused by sequestration of lymphocytes into secondary lymphoid tissues and thymus. FTY720 is rapidly converted to （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] by sphingosine kinase 2 in vivo. （S）-FTY720-P acting as a potent agonist of S1P receptor type 1 （S1P1）, induces long-term down-regulation of S1P1 on lymphocytes, and thereby inhibits the migration of lymphocytes toward S1P. Thus, it is presumed that FTY720-induced lymphocyte sequestration is due to the inhibition of S1P/S1P1-dependent lymphocyte egress from secondary lymphoid tissues and thymus by its active metabolite （S）-FTY720-P. Throughout the analysis of the mechanism of action of FTY720, it is clarified that S1P/S1P1 interaction plays an important role for lymphocyte egress from secondary lymphoid tissues and thymus.
