Objective:To investigate mechanisms whereby phospholipase D1(PLD1)promotes pancreatic ductal adenocarcinoma(PDAC)progression.Methods:Targets were identified by screening the Genomic Spatial Event(GSE)database for genes differentially expressed in metastatic and primary tumors.Xenograft models were constructed by orthotopic injection of KPC cells into the mouse pancreas.Differential PLD1 expression in paired primary tumors and liver metastases derived from C57 mice and PDAC patients was confirmed using immunohistochemical staining.The effect of PLD1 expression on PDAC prognosis was assessed using a PDAC tissue microarray and clinical data.The effect of PLD1 expression on PDAC metastasis was assessed using transwell migration and scratch assays of cell lines ectopically expressing/silencing PLD1.The role of PLD1 in tumor metastasis was investigated using xenograft models constructed by orthotopic injection of PLD1-overexpression cell lines or vector control into the pancreas of C57 mice.Growth of primary tumors and liver metastases was monitored using bioluminescent imaging.The role of PLD1 in tumor progression was assessed using western blotting,transwell migration and scratch assays,and PLD1 enzyme-mutation cell lines.Downstream PLD1 target genes were identified using quantitative real-time PCR(qPCR),transcriptome sequencing,and response blocking.The effect of downstream target FSTL1 on liver metastasis in mice was assessed using bioluminescent imaging.Results:PLD1 expression was significantly higher in metastases than in primary tumors in KPC mice and patients.In the tissue microarray analysis,PLD1 expression was associated with diminished survival in PDAC patients;PLD1 overexpression in MIA PaCa-2 cells or knockdown in SW1990 cells could significantly affect the ability of invasion and migration.Xenograft models were established via orthotopic injections of the KPC cell line into the pancreas.Bioluminescent imaging demonstrated that PLD1 overexpression significantly increased signal intensity in the mouse liver(P<0.01);Treating the SW1990 cell line with PA and choline(PLD1 pathway products)did not restore loss of PDAC cell migration and invasion ability.Transwell and scratch assays in KRM,a PLD1 catalytic-mutation cell line,suggested that PLD1 activity is not required for PDAC metastasis;Transcriptome sequencing identified FSTL1 as a downstream molecule of PLD1.qPCR confirmed the consistency of mRNA levels between PLD1 and FSTL1.A blocking-rescue experiment suggested that FSTL1 is a downstream target of PLD1.A splenectomy metastasis model was constructed by injecting nude mice with tumor cells overexpressing FSTL1 and the results confirmed that overexpression of FSTL1 could induce liver metastases in PDAC cell due to tumor progression.Conclusion:PLD1 upregulates FSTL1 expression,promotes epithelial-mesenchymal transition of tumor cells,and enhances PDAC metastasis.Thus,PLD1 blockade could inhibit PDAC progression.

Objective:To investigate mechanisms whereby phospholipase D1(PLD1)promotes pancreatic ductal adenocarcinoma(PDAC)progression.Methods:Targets were identified by screening the Genomic Spatial Event(GSE)database for genes differentially expressed in metastatic and primary tumors.Xenograft models were constructed by orthotopic injection of KPC cells into the mouse pancreas.Differential PLD1 expression in paired primary tumors and liver metastases derived from C57 mice and PDAC patients was confirmed using immunohistochemical staining.The effect of PLD1 expression on PDAC prognosis was assessed using a PDAC tissue microarray and clinical data.The effect of PLD1 expression on PDAC metastasis was assessed using transwell migration and scratch assays of cell lines ectopically expressing/silencing PLD1.The role of PLD1 in tumor metastasis was investigated using xenograft models constructed by orthotopic injection of PLD1-overexpression cell lines or vector control into the pancreas of C57 mice.Growth of primary tumors and liver metastases was monitored using bioluminescent imaging.The role of PLD1 in tumor progression was assessed using western blotting,transwell migration and scratch assays,and PLD1 enzyme-mutation cell lines.Downstream PLD1 target genes were identified using quantitative real-time PCR(qPCR),transcriptome sequencing,and response blocking.The effect of downstream target FSTL1 on liver metastasis in mice was assessed using bioluminescent imaging.Results:PLD1 expression was significantly higher in metastases than in primary tumors in KPC mice and patients.In the tissue microarray analysis,PLD1 expression was associated with diminished survival in PDAC patients;PLD1 overexpression in MIA PaCa-2 cells or knockdown in SW1990 cells could significantly affect the ability of invasion and migration.Xenograft models were established via orthotopic injections of the KPC cell line into the pancreas.Bioluminescent imaging demonstrated that PLD1 overexpression significantly increased signal intensity in the mouse liver(P<0.01);Treating the SW1990 cell line with PA and choline(PLD1 pathway products)did not restore loss of PDAC cell migration and invasion ability.Transwell and scratch assays in KRM,a PLD1 catalytic-mutation cell line,suggested that PLD1 activity is not required for PDAC metastasis;Transcriptome sequencing identified FSTL1 as a downstream molecule of PLD1.qPCR confirmed the consistency of mRNA levels between PLD1 and FSTL1.A blocking-rescue experiment suggested that FSTL1 is a downstream target of PLD1.A splenectomy metastasis model was constructed by injecting nude mice with tumor cells overexpressing FSTL1 and the results confirmed that overexpression of FSTL1 could induce liver metastases in PDAC cell due to tumor progression.Conclusion:PLD1 upregulates FSTL1 expression,promotes epithelial-mesenchymal transition of tumor cells,and enhances PDAC metastasis.Thus,PLD1 blockade could inhibit PDAC progression.

Objective To optimize and simplify the survey method of Oncomelania hupensis snail in marshland endemic re?gion of schistosomiasis and increase the precision,efficiency and economy of the snail survey. Methods A quadrate experimen?tal field was selected as the subject of 50 m×50 m size in Chayegang marshland near Henghu farm in the Poyang Lake region and a whole?covered method was adopted to survey the snails. The simple random sampling,systematic sampling and stratified ran?dom sampling methods were applied to calculate the minimum sample size,relative sampling error and absolute sampling error. Results The minimum sample sizes of the simple random sampling,systematic sampling and stratified random sampling meth?ods were 300,300 and 225,respectively. The relative sampling errors of three methods were all less than 15%. The absolute sampling errors were 0.221 7,0.302 4 and 0.047 8,respectively. Conclusion The spatial stratified sampling with altitude as the stratum variable is an efficient approach of lower cost and higher precision for the snail survey.