Shin Kibe

Autophagy inhibition enhances antiproliferative effect of salinomycin in pancreatic cancer cells

BACKGROUNDnSalinomycin has cytotoxic effects on various types of malignancy and induces autophagy. However, it has not been clarified whether autophagy induced by salinomycin treatment has a protective or cytotoxic role. We investigated whether salinomycin affects autophagy in pancreatic cancer cells and whether autophagy induced by salinomycin treatment has a protective or cytotoxic role in these cells.nnnMETHODSnWe investigated the effect of salinomycin using three pancreatic cancer cell lines. We investigated effect on proliferation and the CD133 positive fraction using flow cytometry. In addition, we monitored the change in autophagic activity after salinomycin treatment using fluorescent immunostaining, western blotting, and flow cytometry. Finally, knockdown of ATG5 or ATG7 by siRNA was used to investigate the impact of autophagy inhibition on sensitivity to salinomycin.nnnRESULTSnSalinomycin suppressed the proliferation of pancreatic cancer cells in a concentration dependent manner, and reduced the CD133 positive fraction. Salinomycin enhanced autophagy activity in these cells in a concentration dependent manner. Autophagy inhibition made pancreatic cancer cells more sensitive to salinomycin.nnnCONCLUSIONSnOur data provide the first evidence indicating that autophagy induced by salinomycin have a protective role in pancreatic cancer cells. A new therapeutic strategy of combining salinomycin, autophagy inhibitors, and anticancer drugs could hold promise for pancreatic cancer treatment.

Pancreatic stellate cells reorganize matrix components and lead pancreatic cancer invasion via the function of Endo180

Specific cell populations leading the local invasion of cancer are called leading cells. However, the underlying mechanisms are unclear. Here, we identified leading cells in pancreatic cancer and determined how these cells lead and promote cancer cell invasion in the extracellular matrix (ECM). Using three-dimensional matrix remodeling assay, we found that pancreatic stellate cells (PSCs) frequently invaded the collagen matrix with pancreatic cancer cells (PCCs), which invaded behind the invading PSCs. In addition, invading PSCs changed the alignment of collagen fibers, resulting in ECM remodeling and an increase in the parallel fibers along the direction of invading PSCs. Endo180 expression was higher in PSCs than in PCCs, Endo180 knockdown in PSCs attenuated the invasive abilities of PSCs and co-cultured PCCs, and decreased the expression level of phosphorylated myosin light chain 2 (MLC2). In mouse models, Endo180-knockdown PSCs suppressed tumor growth and changes in collagen fiber orientation in co-transplantation with PCCs. Our findings suggest that PSCs lead the local invasion of PCCs by physically remodeling the ECM, possibly via the function of Endo180, which reconstructs the actin cell skeleton by phosphorylation of MLC2.

Adipose tissue-derived stromal cells are sources of cancer-associated fibroblasts and enhance tumor progression by dense collagen matrix: Adipose tissue-derived stromal cells

Although recent studies revealed that adipose tissue accelerates pancreatic tumor progression with excessive extracellular matrix, key players for desmoplasia in the adipose microenvironment remains unknown. Here, we investigated the roles of adipose tissue‐derived stromal cells (ASCs) in desmoplastic lesions and tumor progression by in vitro and in vivo experiments. In a three‐dimensional (3‐D) organotypic fat invasion model using visceral fat from CAG‐EGFP mice, GFP‐positive fibroblastic cells infiltrated toward cancer cells. When tumor cells were inoculated into transplanted visceral fat pads in vivo, tumor weights and stromal components were enhanced compared to subcutaneous and orthotopic tumor cells inoculated without fat pads. Expression of αSMA in established human ASCs was lower compared to cancer associated fibroblasts, and the 3‐D collagen matrices produced by ASCs cultured in cancer cell‐conditioned medium changed from loose to dense structures that affected the motility of cancer cells. Microarray analyses revealed upregulation of S100A4 in ASCs, while S100A4‐positive stromal cells were observed at extrapancreatic invasion sites of human pancreatic cancer. The present findings indicate that ASCs are recruited to extrapancreatic invasion sites and produce dense collagen matrices that lead to enhanced tumor progression. Both inhibition of ASCs recruitment and activation could lead to a novel antistromal therapy.

Basement membrane destruction by pancreatic stellate cells leads to local invasion in pancreatic ductal adenocarcinoma

Stroma invasion is an important step in pancreatic cancer progression. However, how pancreatic ductal adenocarcinoma (PDAC) with ductal structure invades the surrounding stroma has not been clear. Here, we elucidated the mechanism of stromal invasion of PDAC, using organoids. From resected PDAC specimens, we established human PDAC organoids, which developed ductal and basement membrane (BM) structures. When the organoids were co-cultured with pancreatic stellate cells (PSCs) in a collagen matrix, organoids lost their BM and ductal structures, and invaded collagen matrix more frequently than did mono-cultured organoids. Interestingly, direct contact by PSCs to PDAC organoids was observed before BM destruction. Matrix metalloproteinase (MMP) 2 or membrane type-1 MMP (MT1MMP) knockdown in PSCs significantly attenuated BM destruction by PSCs, and retained the ductal structures in organoids. Our results imply that direct contact by PSCs induces BM destruction and stromal invasion of PDAC via MMP2 which binds to MT1MMP on PSCs.

Prognostic Value of Preoperative Nutritional and Immunological Factors in Patients with Pancreatic Ductal Adenocarcinoma

BackgroundPreoperative nutritional and immunological patient factors have been found to be associated with prognostic outcomes of malignant tumors; however, the clinical significance of these factors in pancreatic ductal adenocarcinoma (PDAC) remains controversial.ObjectiveThe aim of this study was to evaluate the prognostic value of nutritional and immunological factors in predicting survival of patients with PDAC.MethodsRetrospective studies of 329 patients who underwent surgical resection for PDAC and 95 patients who underwent palliative surgery were separately conducted to investigate the prognostic impact of tumor-related factors and patient-related factors, including Glasgow Prognostic Score (GPS), modified GPS, Prognostic Nutritional Index (PNI), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio, and lymphocyte/monocyte ratio.ResultsIn multivariate analysis for patients with surgical resection for PDAC, PNI was an independent factor for overall survival (OS) and disease-free survival. The median OS of patients with PNIu2009≤u200945 was significantly shorter than that of patients with PNIu2009>u200945 (17.5 and 36.2xa0months, respectively; pu2009<u20090.001). In multivariate analysis for patients undergoing palliative surgery for PDAC, only NLR was an independent prognosis factor. The median OS of patients with NLRu2009>u20095 was significantly shorter than that of patients with NLRu2009≤u20095 (2.7 and 8.9xa0months, respectively; pu2009<u20090.001).ConclusionsPNI in patients with surgical resection and NLR in patients with palliative surgery for PDAC may be useful prognostic factors.