Jiongxin Xiong

Blockade of sonic hedgehog signal pathway enhances antiproliferative effect of EGFR inhibitor in pancreatic cancer cells

AbstractAim:To investigate the expression of sonic hedgehog (SHH) and epidermal growth factor receptor (EGFR) signal molecules in pancreatic cancer cells, and to assess the inhibitory effects through the blockade of the SHH and EGFR signaling pathways by cyclopamine and Iressa, respectively.Methods:The expression of SHH and EGFR in pancreatic cancer cell lines (PANC-1, SUIT-2, and ASPC-1) was detected by RT-PCR and Western blot analysis. After treatment with different concentrations of cyclopamine, alone or in combination with Iressa, the antiproliferative effect on pancreatic cancer cells was analyzed by methyl thiazolyl tetrazolium assays. A flow cytometry analysis was used to detect the cellular cycle distribution and apoptosis of pancreatic cancer cells.Results:All of the 3 pancreatic cancer cell lines expressed SHH, Smoothened (SMO), and EGFR. Cyclopamine could downregulate the expression of EGFR in all cell lines. Cyclopamine or Iressa could induce a growth inhibitory effect in a dose-dependent manner. Moreover, the combined use of 2.5 μmol/L cyclopamine and 1 μmol/L Iressa induced an enhanced inhibitory effect and a greater apoptosis rate than any agent alone. The percentage of the cell population of the G0/G1 and sub-G1 phases was significantly increased along with the increasing dose of cyclopamine and/or Iressa.Conclusion:The blockade of the sonic hedgehog signal pathway enhances the antiproliferative effect of the EGFR inhibitor through the downregulation of its expression in pancreatic cancer cells. The simultaneous blockade of SHH and EGFR signaling represents possible targets of new treatment strategies for pancreatic carcinoma.

Pancreaticoduodenectomy with Vascular Resection for Local Advanced Pancreatic Head Cancer: A Single Center Retrospective Study

IntroductionPancreaticoduodenectomy with vascular resection remains a controversial approach for patients with local advanced pancreatic head cancer for the lack of evidences of survival and quality of life benefits. The aim of this study was to evaluate whether patients of pancreatic head cancer benefit on quality of life, survival, and treatment cost from pancreaticoduodenectomy with vascular resection compared with palliative therapy.Materials and MethodsTwo hundred fourteen patients of pancreatic head cancer whose pancreatic head could not be dissected free from adjacent vascular were involved in this study. Eighty of these patients underwent pancreaticoduodenectomy with vascular resection, whereas other patients underwent palliative therapy.ResultsPancreaticoduodenectomy with artery resection offered worse outcomes on almost all aspects of quality of life and survival compared with palliative therapy. Pancreaticoduodenectomy with vein resection offered better 5-year survival compared with palliative therapy, whereas palliative therapy offered better quality of life after surgery.ConclusionPancreaticoduodenectomy with artery resection is nonsensical on treatment of pancreatic head cancer with artery adhesion/invasion. As for patients with vein adhesion/invasion, pancreaticoduodenectomy with vein resection should be performed cautiously. When actual vein invasion is very possible to have taken place, the choice of treatment strategy should be considered carefully by the pancreatic surgeons.

Transcriptional upregulation of MT2-MMP in response to hypoxia is promoted by HIF-1α in cancer cells.

Hypoxia is a critical event in solid tumor development, invasion, and metastasis. Cellular adaptation to hypoxic microenvironment is essential for tumor progression and is largely mediated by hypoxia‐inducible factor‐1α (HIF‐1α) through coordinated regulation of hypoxia‐responsive genes. In this study, we found that membrane type‐2 matrix metalloproteinase (MT2‐MMP), one of the matrix metalloproteinase (MMP) family members, was a novel hypoxia‐responsive gene and was upregulated by HIF‐1α under hypoxia. When cancer cells were subjected to hypoxia (1% O2) treatment, the mRNA and protein levels of MT2‐MMP were significantly increased in a time‐dependent manner in all three tested cancer cell lines including pancreatic cancer cells (PANC‐1), nonsmall cell lung cancer cells (A‐549), and cervix cancer cells (HeLa). Further analyses indicated that there were two hypoxia‐responsive elements (HREs) in the MT2‐MMP promoter, and HRE1 but not HRE2 was essential for MT2‐MMP transcriptional activation under hypoxia. HIF‐1α specifically and directly bound to MT2‐MMP promoter was analyzed by HIF‐1α binding/competition and chromatin immunoprecipitation (ChIP) assays. Furthermore, we found that upregulation of MT2‐MMP under hypoxia could confer resistance to hypoxia‐induced apoptosis and increase invasiveness of cancer cells. These findings provided a new insight into how cancer cells overcome hypoxic stress and trend to survive and invade, demonstrated a new regulatory mechanism of MT2‐MMP expression in caner cells, and also revealed that MT2‐MMP was a novel hypoxia‐responsive gene and was upregulated by HIF‐1α under hypoxia.

Regulation of ω-3 fish oil emulsion on the SIRS during the initial stage of severe acute pancreatitis

The aim of this study was to explore the effects of parenteral supplementation with ω-3 fish oil emulsion (Omegaven®) on systemic inflammatory response syndrome (SIRS) during the initial stage of severe acute pancreatitis (SAP). In a prospective, randomized and controlled trial, 60 patients with SAP were randomized either to treat with conventional therapy (Con group, n=30) or conventional therapy plus intravenous supplementation with ω-3 fish oil emulsion 0.2 g/kg every day (FO group, n=30). The effects were analyzed by the SIRS-related indexes. The results showed that APACHE-II scores in FO group were significantly lower, and the gap increased much farther after the 4th day than those in Con group (P<0.05). Fluid equilibrium time became shorter markedly in FO group than in Con group (5.1±2.2 days vs 8.4±2.3 days). In FO group, SIRS scores were markedly decreased and the SIRS state vanished after the 4th day; Plasma level of TNF-α was significantly reduced, while IL-10 decreased markedly, most prominently between the 4th and 7th day, and the ratio of IL-10/TNF-α raised as compared with Con group (P<0.05). During the initial stage of SAP, parenteral supplementation with ω-3 fish oil emulsion could efficiently lower the magnitude and persistence time of the SIRS, markedly retrieve the unbalance of the pro-/anti-inflammatory cytokines, improve severe condition of illness and may provide a new way to regulate the SIRS.SummaryThe aim of this study was to explore the effects of parenteral supplementation with ω-3 fish oil emulsion (Omegaven®) on systemic inflammatory response syndrome (SIRS) during the initial stage of severe acute pancreatitis (SAP). In a prospective, randomized and controlled trial, 60 patients with SAP were randomized either to treat with conventional therapy (Con group, n=30) or conventional therapy plus intravenous supplementation with ω-3 fish oil emulsion 0.2 g/kg every day (FO group, n=30). The effects were analyzed by the SIRS-related indexes. The results showed that APACHE-II scores in FO group were significantly lower, and the gap increased much farther after the 4th day than those in Con group (P<0.05). Fluid equilibrium time became shorter markedly in FO group than in Con group (5.1±2.2 days vs 8.4±2.3 days). In FO group, SIRS scores were markedly decreased and the SIRS state vanished after the 4th day; Plasma level of TNF-α was significantly reduced, while IL-10 decreased markedly, most prominently between the 4th and 7th day, and the ratio of IL-10/TNF-α raised as compared with Con group (P<0.05). During the initial stage of SAP, parenteral supplementation with ω-3 fish oil emulsion could efficiently lower the magnitude and persistence time of the SIRS, markedly retrieve the unbalance of the pro-/anti-inflammatory cytokines, improve severe condition of illness and may provide a new way to regulate the SIRS.

Spontaneous Differentiation of Murine Bone Marrow-Derived Mesenchymal Stem Cells into Adipocytes without Malignant Transformation after Long-Term Culture

Some observations have suggested that extensive culture of adult stem cells can lead to malignant transformation. Therefore, it has become commonplace to use stem cells undergoing little or no in vitro culture to circumvent this presumptive limitation. Recently, a detailed study documented that malignant transformation of adult neural stem cells can be avoided under suitable culture conditions. Here, we report the first demonstration that murine bone marrow-derived mesenchymal stem cells (bMSCs) were propagated in vitro for up to 50 passages without any transformation sign under suitable conditions. However, it must be noted that although the long-term cultured bMSCs were comparable with short-term cultured bMSCs in proliferation, migration and invasion, they lost their pluripotent potential. The long-term cultured bMSCs could only differentiate into adipocytes but not into osteocytes or chondrocytes. In conclusion, murine bMSCs can be propagated in vitro for up to 50 passages with no malignant transformation sign under suitable conditions, but how to sustain their pluripotent potential requires further investigation.

Heparin inhibits the inflammatory response induced by LPS and HMGB1 by blocking the binding of HMGB1 to the surface of macrophages.

High mobility group box 1 protein (HMGB1), a nuclear non-histone DNA-binding protein, is secreted extracellularly during inflammation and is a late mediator of inflammatory responses. The pro-inflammatory activity of recombinant HMGB1 proteins is dependent upon the formation of complexes with other mediators, such as lipopolysaccharide (LPS). This study investigated the influence of heparin on LPS+HMGB1-mediated inflammatory responses in cultured macrophages and a murine sepsis model. HMGB1 promoted the phosphorylation of p38 and ERK1/2. HMGB1 enhanced the induction of the pro-inflammatory cytokine, TNF-α, by LPS in macrophages. Heparin blocked the binding of HMGB1 to the surface of macrophages, and suppressed the phosphorylation of p38 and ERK1/2, but not JNK; TNF-α secretion was also decreased. However, heparin alone did not affect LPS-induced production of TNF-α. Heparin reduced lethality in mice exposed to LPS+HMGB1. To conclude, heparin inhibited LPS-induced HMGB1-amplified inflammatory responses by blocking HMGB1 binding to macrophage surfaces. Heparin could be used therapeutically as an effective inhibitor of HMGB1-associated inflammation.

MiR-652 inhibits acidic microenvironment-induced epithelial-mesenchymal transition of pancreatic cancer cells by targeting ZEB1

Recent evidences suggest that the acidic microenvironment might facilitate epithelial mesenchymal transition (EMT) of tumor cells, while the effects of acidity on EMT of pancreatic cancer (PC) remain undefined. The present study demonstrated that acidity suppressed miR-652 expression, which further promoted EMT process by absenting inhibition on the transcriptional factor ZEB1 expression. At first, we found that acidity remarkably enhanced invasion ability of PC cells accompanying with increased mesenchymal and decreased epithelial markers. Meanwhile, miRNAs-microarray showed that miR-652, the potential regulator of ZEB1, was distinctly decreased in acidity-treated PC cells. Furthermore, restoration of miR-652 reversed acidity-induced EMT by inhibiting ZEB1 expression, while miR-652 inhibitor induced EMT in normal PC cells through promoting ZEB1 expression. Nevertheless, knockdown of ZEB1 significantly suppressed acidity-induced EMT in PC cells, but ZEB1 overexpression rescued the EMT which was inhibited by miR-652 overexpression. The in vivo results showed that the tumor growth and liver metastasis were remarkably retarded by both miR-652 overexpression and ZEB1 knockdown. The clinical samples further revealed that miR-652 was decreased in PC tissues and antagonistically correlated with ZEB1 expression, associating with late tumor stage, lymphatic invasion and metastasis. In conclusion, our study indicated a novel acidity/miR-652/ZEB1/EMT axis in the tumorigenesis of PC.

Effect of HIF-1α on VEGF-C induced lymphangiogenesis and lymph nodes metastases of pancreatic cancer

The effect of hypoxia inducible factor-1α (HIF-1α) on vascular endothelial growth factor C (VEGF-C) and the correlation between HIF-1α and lymphangiogenesis and lymph nodes metastases (LNM) in pancreatic cancer were investigated. Immunohistochemical SP method was used to detect the protein expression of HIF-1α and VEGF-C, and Lymphatic vessel density (LVD) was determined by stain of VEGFR-3, collagen type IV in 75 pancreatic head cancers from regional pancreatectomy (RP) during Dec. 2001 to Dec. 2003. The relationship between HIF-1α and VEGF-C, lymphangiogenesis, LNM was analyzed statistically. The results showed that the positive expression rate of HIF-1α and VEGF-C in pancreatic cancer tissues was 48.00 % (36/75) and 65.33 % (49/75) respectively. In positive group of HIF-1α, the positive rate of VEGF-C and LVD, and LVD rate was 80.56 % (29/36), 13.22±3.76 and 88.89 % (32/36) respectively, and in negative group of HIF-1α, positive rate of VEGF-C and LVD was 51.28 % (20/39), 5.98±2.17 and 66.67 % (26/39) respectively (P<0.01 or P<0.05). It was suggested that HIF-1α could promote the expression of VEGF-C, lymphangiogenesis and LNM in pancreatic cancer.

MiR-744 increases tumorigenicity of pancreatic cancer by activating Wnt/β-catenin pathway.

The Wnt/β-catenin signaling pathway, commonly hyperactivated in pancreatic cancer, has been reported to play an important role in the maintenance of stemness of cancer stem cells (CSCs), which is closely related to the progression of pancreatic cancer. Therefore, exploring the regulatory mechanism in Wnt/β-catenin signaling may provide valuable clinical targets for cancer therapy. In the current study, we demonstrated that upregulation of miR-744 in pancreatic cancer promoted Wnt/β-catenin signaling by directly targeting secreted frizzled-related protein 1 (SFRP1), glycogen synthase kinase 3β (GSK3β), and transducin-like enhancer of split 3 (TLE3), important negative modulators of Wnt/β-catenin signaling. Expression of miR-744 was markedly upregulated in pancreatic cancer and positively correlated with poor patient survival. Furthermore, we found that overexpressing miR-744 enhanced, while inhibiting miR-744 reduced, the stem cell-like phenotype of pancreatic cancer cells in vitro. Importantly, in vivo model of human-derived pancreatic xenografts showed that miR-744 upregulation enhanced the tumorigenicity of pancreatic cancer cells. These findings suggest that miR-744 plays a vital role in promoting the stem cell-like phenotype of pancreatic cancer cells, and may represent a novel prognostic biomarker and therapeutic target.

Minimally invasive percutaneous catheter drainage versus open laparotomy with temporary closure for treatment of abdominal compartment syndrome in patients with early-stage severe acute pancreatitis

This study aimed to examine the clinical efficacy of minimally invasive percutaneous catheter drainage (PCD) versus open laparotomy with temporary closure in the treatment of abdominal compartment syndrome (ACS) in patients with early-stage severe acute pancreatitis (SAP). Clinical data of 212 patients who underwent PCD and 61 patients who were given open laparotomy with temporary closure in our hospital over the last 10-year period were retrospectively analyzed, and outcomes were compared, including total and post-decompression intensive care unit (ICU) and hospital stays, physiological data, organ dysfunction, complications, and mortality. The results showed that the organ dysfunction scores were similar between the PCD and open laparotomy groups 72 h after decompression. In the PCD group, 134 of 212 (63.2%) patients required postoperative ICU support versus 60 of 61 (98.4%) in the open laparotomy group (P<0.001). Additionally, 87 (41.0%) PCD patients experienced complications as compared to 49 of 61 (80.3%) in the open laparotomy group (P<0.001). There were 40 (18.9%) and 32 (52.5%) deaths, respectively, in the PCD and open laparotomy groups (P<0.001). In conclusion, minimally invasive PCD is superior to open laparotomy with temporary closure, with fewer complications and deaths occurring in PCD group.SummaryThis study aimed to examine the clinical efficacy of minimally invasive percutaneous catheter drainage (PCD) versus open laparotomy with temporary closure in the treatment of abdominal compartment syndrome (ACS) in patients with early-stage severe acute pancreatitis (SAP). Clinical data of 212 patients who underwent PCD and 61 patients who were given open laparotomy with temporary closure in our hospital over the last 10-year period were retrospectively analyzed, and outcomes were compared, including total and post-decompression intensive care unit (ICU) and hospital stays, physiological data, organ dysfunction, complications, and mortality. The results showed that the organ dysfunction scores were similar between the PCD and open laparotomy groups 72 h after decompression. In the PCD group, 134 of 212 (63.2%) patients required postoperative ICU support versus 60 of 61 (98.4%) in the open laparotomy group (P<0.001). Additionally, 87 (41.0%) PCD patients experienced complications as compared to 49 of 61 (80.3%) in the open laparotomy group (P<0.001). There were 40 (18.9%) and 32 (52.5%) deaths, respectively, in the PCD and open laparotomy groups (P<0.001). In conclusion, minimally invasive PCD is superior to open laparotomy with temporary closure, with fewer complications and deaths occurring in PCD group.