Shingo Kozono

Pirfenidone Inhibits Pancreatic Cancer Desmoplasia by Regulating Stellate Cells

Pancreatic stellate cells (PSC), which are implicated in desmoplasia in pancreatic cancer, enhance the malignancy of cancer cells and confer resistance to established treatments. We investigated whether the antifibrotic agent pirfenidone can suppress desmoplasia and exert antitumor effects against pancreatic cancer. Primary PSCs were established from pancreatic cancer tissue obtained during surgery. In vitro, pirfenidone inhibited the proliferation, invasiveness, and migration of PSCs in a dose-dependent manner. Although supernatants of untreated PSCs increased the proliferation, invasiveness, and migration of pancreatic cancer cells (PCC), supernatants of pirfenidone-treated PSCs decreased these effects. Exposure to PCC supernatant increased the production of platelet-derived growth factor-A, hepatic growth factor, collagen type I, fibronectin, and periostin in PSCs, which was significantly reduced by pirfenidone. Mice were subcutaneously implanted with PCCs (SUIT-2 cells) and PSCs into the right flank and PCCs alone into the left flank. Oral administration of pirfenidone to these mice significantly reduced tumor growth of co-implanted PCCs and PSCs, but not of PCCs alone. Pirfenidone also decreased the proliferation of PSCs and the deposition of collagen type I and periostin in tumors. In mice with orthotopic tumors consisting of PCCs co-implanted with PSCs, pirfenidone suppressed tumor growth, reduced the number of peritoneal disseminated nodules, and reduced the incidence of liver metastasis. Pirfenidone in combination with gemcitabine more effectively suppressed orthotopic tumor growth compared with pirfenidone or gemcitabine alone. In conclusion, our findings indicate that pirfenidone is a promising antitumor agent for pancreatic cancer, owing to its suppression of desmoplasia through regulating PSCs.

Significance of combination therapy of zoledronic acid and gemcitabine on pancreatic cancer

In the present study, we examined the cytotoxic effects of combination therapy with zoledronic acid (ZOL) and gemcitabine (GEM) on pancreatic cancer cells in vitro and in vivo. Four human pancreatic cancer cell lines were treated with ZOL, GEM or a combination of both, and the effects of the respective drug regimens on cell proliferation, invasion and matrix metalloproteinase (MMP) expression were examined. A pancreatic cancer cell line was also intrasplenically or orthotopically implanted into athymic mice and the effects of these drugs on tumor metastasis and growth in vivo were evaluated by histological and immunohistochemical analyses. Combination treatment with low doses of ZOL and GEM efficiently inhibited the proliferation (P < 0.001) and invasion (P < 0.001) of pancreatic cancer cells in vitro. Western blotting assay revealed that MMP‐2 and MMP‐9 expression levels were decreased after ZOL treatment. In vivo, combined treatment significantly inhibited tumor growth (P < 0.05) and the development of liver metastasis (P < 0.05). These data revealed that ZOL and GEM, when used in combination, have significant antitumor, anti‐metastatic and anti‐angiogenic effects on pancreatic cancer cells. The present study is the first to report the significance of the combination treatment of ZOL and GEM in pancreatic cancer using an in vivo model. These data are promising for the future application of this drug regimen in patients with pancreatic cancer. (Cancer Sci 2012; 103: 58–66)

Pancreatic Cancer Cells Enhance the Ability of Collagen Internalization during Epithelial–Mesenchymal Transition

Background Extracellular matrix (ECM) remodeling is predominantly mediated by fibroblasts using intracellular and extracellular pathways. Although it is well known that extracellular degradation of the ECM by proteases derived from cancer cells facilitates cellular invasion, the intracellular degradation of ECM components by cancer cells has not been clarified. The aim of this study was to characterize collagen internalization, which is the initial step of the intracellular degradation pathway in pancreatic cancer cells, in light of epithelial–mesenchymal transition (EMT). Methodology/Principal Findings We analyzed the function of collagen internalization in two pancreatic cancer cell lines, SUIT-2 and KP-2, and pancreatic stellate cells (PSCs) using Oregon Green 488-gelatin. PSCs had a strong ability for collagen uptake, and the pancreatic cancer cells also internalized collagen although less efficiently. The collagen internalization abilities of SUIT-2 and KP-2 cells were promoted by EMT induced by human recombinant transforming growth factor β1 (P<0.05). Expression of Endo180, a collagen uptake receptor, was high in mesenchymal pancreatic cancer cell lines, as determined by EMT marker expression (P<0.01). Quantitative RT-PCR and western blot analyses showed that Endo180 expression was also increased by EMT induction in SUIT-2 and KP-2 cells. Endo180 knockdown by RNA interference attenuated the collagen uptake (P<0.01) and invasive abilities (P<0.05) of SUIT-2 and KP-2 cells. Conclusions/Significance Pancreatic cancer cells are capable of collagen internalization, which is enhanced by EMT. This ECM clearance system may be a novel mechanism for cellular invasion and a potential therapeutic target in pancreatic cancer.

A minimally invasive and simple screening test for detection of pancreatic ductal adenocarcinoma using biomarkers in duodenal juice.

Objectives The aim of this study was to establish a minimally invasive and simple screening test for detection of pancreatic ductal adenocarcinoma (PDAC) using duodenal juice (DJ). Methods Duodenal juice was collected prospectively before endoscopic retrograde cholangiopancreatography in 46 patients. A protease inhibitor was not added to the samples collected during the initial 2.5 minutes but was added in the latter 2.5 minutes. Thereafter, secretin was administered intravenously, and DJ was subsequently collected for additional 10 minutes. The sensitivities of carcinoembryonic antigen (CEA), S100 calcium-binding protein P (S100P), and interleukin 8 in DJ and pancreatic juice were assessed. Results There were 30 patients with PDAC and 16 with benign lesions. It was possible to collect an adequate amount of DJ without secretin administration. In the PDAC group, CEA concentrations in DJ were significantly higher than those in the benign group, even without the use of a protease inhibitor. S100P levels in DJ in the PDAC group were significantly higher than those in the benign group in the presence of the protease inhibitor. Conclusions Duodenal juice collection during routine upper endoscopy and assessments of CEA and S100P in DJ might become a useful screening test for detection of PDAC.

Kindlin-2 expression in peritumoral stroma is associated with poor prognosis in pancreatic ductal adenocarcinoma

Objectives Kindlin-2 is a novel focal adhesion protein reported to be expressed in breast, lung, and gastric cancers. This study aimed to investigate the significance of kindlin-2 expression in pancreatic ductal adenocarcinomas (PDACs). Methods We performed immunohistochemical analysis on kindlin-2 on PDAC samples from 95 patients. We investigated the association between kindlin-2 expression and clinicopathological parameters of PDAC and the survival time of patients with PDAC who underwent pancreatectomy. Results Kindlin-2 was highly expressed in the peritumoral stroma of PDACs. Stromal kindlin-2 expression was related to nodal metastasis (P = 0.03). Univariate analysis showed that patients with positive kindlin-2 expression had significantly shorter survival times than those with negative kindlin-2 expression (P = 0.01). In addition, multivariate analysis revealed that kindlin-2 expression was an independent factor of poor prognosis in patients with PDAC after R0 resection (RR = 2.15; P = 0.04). Conclusions Kindlin-2 expression in stromal components is significantly associated with poor prognosis of patients with PDAC, suggesting that kindlin-2 is a prognostic marker for patients with PDAC.

Kindlin-1 expression is involved in migration and invasion of pancreatic cancer

Kindlin-1 is a novel focal adhesion protein that belongs to the kindlin family. Expression of kindlin-1 has recently been reported in lung and colon cancers, but there have been no studies on its expression in pancreatic cancer. This study aimed to investigate the expression and function of kindlin-1 in pancreatic cancer. Quantitative RT-PCR of Kindlin-1 mRNA was performed in various pancreatic cancer cell lines as well as normal pancreatic epithelial cells and fibroblasts. Immunohistochemical analysis of kindlin-1 was performed for pancreatic cancer tissues. The effects of kindlin-1 on the proliferation, migration and invasion of pancreatic cancer cells were investigated using an RNA interference technique. Kindlin-1 mRNA was highly expressed in the pancreatic cancer cell lines, but only slightly expressed in normal pancreatic epithelial cells and fibroblasts. The Kindlin-1 protein was heterogeneously expressed in the cytoplasm and membrane of pancreatic cancer cells, while normal ductal epithelial cells and stromal cells showed no expression. In vitro experiments involving knockdown of kindlin-1 in AsPC-1 and KP-2 cells revealed that the migratory and invasive abilities of the cells were significantly decreased (P<0.001), while the proliferation abilities were not affected. The present findings suggest that kindlin-1 expression is involved in the progression of pancreatic cancer via enhancement of cell migration and invasion.

MAL2 expression predicts distant metastasis and short survival in pancreatic cancer

BACKGROUND Pancreatic cancer is associated with a devastating prognosis, partially because of its aggressive metastatic ability. Identification of prognostic markers of metastasis would be useful in the clinical management of postoperative patients with pancreatic cancer. Mal, T-cell differentiation protein 2 (MAL2) has been identified as a molecule predictive of metastases; the clinical relevance of MAL2 in pancreatic cancer is unknown. METHODS Orthotopic human pancreatic cancer xenografts from the pancreatic cancer cell line SUIT-2 were established in nude mice. Only liver metastasis was harvested and cultured. These metastatic cycles were repeated 5 times to establish a highly metastatic cell line, termed metastatic SUIT-2 (MS). We investigated proliferation and motility of MS cells compared with those of the parent SUIT-2. Microarray analysis was performed to investigate differences in gene expression. We also performed immunohistochemical analysis of 89 formalin-fixed, paraffin-embedded human pancreatic cancer tissue samples to investigate the clinical significance of MAL2 expression. RESULTS MS cells showed a greater metastatic rate after orthotopic implantation than parental SUIT-2. MS cells had increased motility but decreased proliferation compared with parental SUIT-2. Microarray analyses showed that 26 genes were significantly upregulated (>10-fold) in MS cells compared with parental SUIT-2, particularly MAL2 expression. Immunohistochemical analysis showed that high expression of MAL2 was associated with a lesser survival of postoperative patients (P = .03) and a high rate of distant metastasis (P = .008). CONCLUSION We characterized a newly established pancreatic cancer cell line with highly metastatic potential. MAL2 is a promising predictive marker for distant metastasis and short survival in patients with resected pancreatic cancer.

Expression of glucagon-like Peptide 1 receptor and its effects on biologic behavior in pancreatic neuroendocrine tumors.

Objectives Glucagon-like peptide 1 (GLP-1) interacts with its specific high-affinity receptor, glucagon-like peptide 1 receptor (GLP-1R), and induces cellular growth and inhibition of apoptosis in pancreatic &bgr; cells. The aim of this study was to investigate the significance of GLP-1R expression in pancreatic neuroendocrine tumors (PNETs). Methods Glucagon-like peptide 1 receptor expression was semiquantitatively evaluated by immunohistochemical staining in 50 resected PNETs, and the correlation between the GLP-1R expression and clinicopathologic features was investigated. Results There were 23 PNETs with positive expression and 27 PNETs with negative expression of GLP-1R. Positive expression of GLP-1R was more frequently observed in insulinoma than in gastrinoma and nonfunctioning tumor (P < 0.05). Although expression status of GLP-1R did not affect the prognosis of the patients with PNETs (P = 0.82), most of the metastatic sites such as lymph node and liver showed positive staining for GLP-1R (8 of 11 PNETs, 73%). Conclusions Glucagon-like peptide 1 receptor would be a diagnostic marker of insulinoma and might become a molecular target for treatment of metastatic PNETs and hormonal regulation of insulin.

CD271⁺ subpopulation of pancreatic stellate cells correlates with prognosis of pancreatic cancer and is regulated by interaction with cancer cells.

Pancreatic stellate cells (PSCs) play a crucial role in the aggressive behavior of pancreatic cancer. Although heterogeneity of PSCs has been identified, the functional differences remain unclear. We characterized CD271+ PSCs in human pancreatic cancer. Immunohistochemistry for CD271 was performed for 31 normal pancreatic tissues and 105 pancreatic ductal adenocarcinomas (PDACs). We performed flow cytometry and quantitative RT-PCR, and assessed CD271 expression in PSCs isolated from pancreatic tissues and the changes in CD271 expression in PSCs cocultured with cancer cells. We also investigated the pattern of CD271 expression in a SCID mouse xenograft model. In the immunohistochemical analyses, the CD271-high staining rates in pancreatic stroma in normal pancreatic tissues and PDACs were 2/31 (6.5%) and 29/105 (27.6%), respectively (p = 0.0069). In PDACs, CD271+ stromal cells were frequently observed on the edge rather than the center of the tumors. Stromal CD271 high expression was associated with a good prognosis (p = 0.0040). Flow cytometric analyses demonstrated CD271-positive rates in PSCs were 0–2.1%. Quantitative RT-PCR analyses revealed that CD271 mRNA expression was increased in PSCs after coculture with pancreatic cancer cells. However, the level of CD271 mRNA expression subsequently decreased after the transient increase. Furthermore, CD271 mRNA expression was decreased in PSCs migrating toward pancreatic cancer cells through Matrigel. In the xenograft model, CD271+ PSCs were present at tumor margins/periphery and were absent in the tumor core. In conclusion, CD271 was expressed in PSCs around pancreatic tumors, but not in the center of the tumors, and expression decreased after long coculture with pancreatic cancer cells or after movement toward pancreatic cancer cells. These findings suggest that CD271+ PSCs appear at the early stage of pancreatic carcinogenesis and that CD271 expression is significantly correlated with a better prognosis in patients with PDAC.

Peritoneal myofibroblasts at metastatic foci promote dissemination of pancreatic cancer

Myofibroblasts in the stroma of pancreatic cancers promote tumor proliferation, invasion and metastasis by increasing extracellular matrix and secretion of several growth factors. In contrast, the role of myofibroblasts at peritoneally disseminated sites of pancreatic cancer has not yet been determined. This study was designed to assess the role of myofibroblasts at peritoneally disseminated sites of pancreatic cancer. Three primary cultures of human peritoneal myofibroblasts (hPMFs) were established from disseminated sites of pancreatic cancer and their interactions with the SUIT-2 and CAPAN-1 human pancreatic cancer cell lines were analyzed in vitro. Using a model in BALB/c nu/nu mice, we compared the dissemination ability of intraperitoneally implanted pancreatic cancer cells, with and without hPMFs, and examined the presence of green fluorescent protein (GFP)-labeled hPMFs at peritoneally disseminated sites in mice. hPMFs significantly promoted the migration and invasion of pancreatic cancer cells (P<0.05), while the cancer cells significantly promoted the migration and invasion of hPMFs (P<0.05). In vivo, the number of peritoneally disseminated nodules, more than 3 mm in size, was significantly greater in mice implanted with cancer cells plus hPMFs compared to mice implanted with cancer cells alone, with GFP-labeled hPMFs surviving in the peritoneal cavity of the former. hPMFs promote the peritoneal dissemination of pancreatic cancer. The cancer-stromal cell interaction in the peritoneal cavity may be a new therapeutic target to prevent the dissemination of pancreatic cancer.