A Case of Pancreatic Neuroendocrine Tumor with Liver Metastases Demonstrating the Possibility of Enhanced ACTH Production by the SACI Test.

Objective: ACTH-producing pancreatic NETs have a propensity to metastasize, and in patients with metastases, there is no established method yet to precisely determine if the excess ACTH is produced by the primary or the metastatic tumors. Localizing the source of production of ACTH in such cases is important for devising suitable treatment strategies and evaluating the benefit of local therapies from the viewpoint of control of Cushing's syndrome. Methods: We performed the selective arterial calcium injection (SACI) test combined with selective portal and hepatic venous sampling in a 32-year-old female patient with ectopic ACTH-producing pancreatic NET and liver metastases. Results: The blood level of ACTH after Ca loading was significantly elevated only in the vessels thought to be directly feeding the pancreatic tumor, and Ca loading from any artery did not significantly increase ACTH concentrations in the hepatic veins compared to the main trunk of the portal vein. Conclusions: The present case demonstrates that there might be an ACTH-producing p-NET that responds to Ca loading. Further in vitro studies are required to validate this possibility.

Intermittent Fasting Sustainably Improves Glucose Tolerance in Normal Weight Male Mice Through Histone Hyperacetylation.

To explore the mechanism by which intermittent fasting (IF) exerts prolonged effects after discontinuation, we examined mice that had been subjected to 4 cycles of fasting for 72 hours and ad libitum feeding for 96 hours per week (72hIF), followed by 4 weeks of ad libitum feeding, focusing on expression of genes for lipid metabolism in the skeletal muscle and histone acetylation in the promoter region. The 72hIF regimen resulted in metabolic remodeling, characterized by enhanced lipid utilization and mitochondrial activation in the muscle. This long-term IF (72hIF) caused stronger metabolic effects than alternate day fasting (24hIF) wherein fasting and refeeding are repeated every 24 hours. Upregulation of lipid oxidation genes and an increase in oxygen utilization were sustained even at 4 weeks after discontinuation of 72hIF, associated with histone hyperacetylation of the promoter region of uncoupling protein 3 (Ucp3) and carnitine palmitoyl transferase 1b (Cpt1b) genes. An increase in leucine owing to fasting-induced muscle degradation was suggested to lead to the histone acetylation. These findings support the previously unappreciated notion that sustainable promotion of histone acetylation in lipid oxidation genes of the muscle and adipose tissues during and after IF may contribute to sustained metabolic effects of IF.

ERAP2 is a novel target involved in autophagy and activation of pancreatic stellate cells via UPR signaling pathway.

BACKGROUND/OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) is characterized by excessive desmoplasia and autophagy-dependent tumorigenic growth. Pancreatic stellate cells (PSCs) as a predominant stromal cell type play a critical role in PDAC biology. We have previously reported that autophagy facilitates PSC activation, however, the mechanism remains unknown. We investigated the mechanism of autophagy in PSC activation. METHODS: We compared gene expression profiles between patient-derived PSCs from pancreatic cancer and chronic pancreatitis using a microarray. The stromal expression of target gene in specimen of PDAC patients (n = 63) was analyzed. The effect of target gene on autophagy and activation of PSCs was investigated by small interfering RNAs transfection, and the relationship between autophagy and ER stress was investigated. We analyzed the growth and fibrosis of xenografted tumor by orthotopic models. RESULTS: In analysis of gene expression microarray, endoplasmic reticulum aminopeptidase 2 (ERAP2) upregulated in cancer-associated PSCs was identified as the target gene. High stromal ERAP2 expression is associated with a poor prognosis of PDAC patients. Knockdown of ERAP2 inhibited unfolded protein response mediated autophagy, and led to inactivation of PSCs, thereby attenuating tumor-stromal interactions by inhibiting production of IL-6 and fibronectin. In vivo, the promoting effect of PSCs on xenografted tumor growth and fibrosis was inhibited by ERAP2 knockdown. CONCLUSIONS: Our findings demonstrate a novel mechanism of PSCs activation regulated by autophagy. ERAP2 as a promising therapeutic target may provide a novel strategy for the treatment of PDAC.

Activation of the intestinal tissue renin-angiotensin system by transient sodium loading in salt-sensitive rats.

BACKGROUND: The renal tissue renin-angiotensin system is known to be activated by salt loading in salt-sensitive rats; however, the response in other organs remains unclear. METHOD: Spontaneously hypertensive rats were subjected to normal tap water or transient high-salt-concentration water from 6 to 14 weeks of age and were thereafter given normal tap water. From 18 to 20 weeks of age, rats given water with a high salt concentration were treated with an angiotensin II type 1 receptor blocker, valsartan. RESULTS: Sustained blood pressure elevation by transient salt loading coincided with a persistent decrease in the fecal sodium content and sustained excess of the circulating volume in spontaneously hypertensive rats. Administration of valsartan sustainably reduced the blood pressure and normalized the fecal sodium levels. Notably, transient salt loading persistently induced the intestinal tissue renin-angiotensin system and enhanced sodium transporter expression exclusively in the small intestine of salt-sensitive rats, suggesting the potential connection of intestinal sodium absorption to salt sensitivity. CONCLUSION: These results reveal the previously unappreciated contribution of the intestinal tissue renin-angiotensin system to sodium homeostasis and blood pressure regulation in the pathophysiology of salt-sensitive hypertension.

Transient Dexamethasone Loading Induces Prolonged Hyperglycemia in Male Mice With Histone Acetylation in Dpp-4 Promoter.

Glucocorticoid causes hyperglycemia, which is common in patients with or without diabetes. Prolonged hyperglycemia can be experienced even after the discontinuation of glucocorticoid use. In the present study, we examined the time course of blood glucose level in hospital patients who received transient glucocorticoid treatment. In addition, the mechanism of prolonged hyperglycemia was investigated by using dexamethasone (Dexa)-treated mice and cultured cells. The blood glucose level in glucose tolerance tests, level of insulin and glucagon-like peptide 1 (GLP-1), and the activity of dipeptidyl peptidase 4 (DPP-4) were examined during and after Dexa loading in mice, with histone acetylation level of the promoter region. Mice showed prolonged hyperglycemia during and after transient Dexa loading accompanied by persistently lower blood GLP-1 level and higher activity of DPP-4. The expression level of Dpp-4 was increased in the mononuclear cells and the promoter region of Dpp-4 was hyperacetylated during and after the transient Dexa treatment. In vitro experiments also indicated development of histone hyperacetylation in the Dpp-4 promoter region during and after Dexa treatment. The upregulation of Dpp-4 in cultured cells was significantly inhibited by a histone acetyltransferase inhibitor. Moreover, the histone hyperacetylation induced by Dexa was reversible by treatment with a sirtuin histone deacetylase activator, nicotinamide mononucleotide. We identified persistent reduction in blood GLP-1 level with hyperglycemia during and after Dexa treatment in mice, associated with histone hyperacetylation of promoter region of Dpp-4. The results unveil a novel mechanism of glucocorticoid-induced hyperglycemia, and suggest therapeutic intervention through epigenetic modification of Dpp-4.

New high-throughput screening detects compounds that suppress pancreatic stellate cell activation and attenuate pancreatic cancer growth.

BACKGROUND/OBJECTIVES: Pancreatic stellate cells (PSCs) are involved in abundant desmoplasia, which promotes cancer cell aggressiveness and resistance to anti-cancer drugs. Therefore, PSCs are suggested to be a promising therapeutic target by attenuating PSC activation to inhibit tumor-stromal interactions with pancreatic cancer cells. Here, we developed a screen to identify compounds that reduce the activity of PSCs and investigated the effect of candidates on pancreatic cancer. METHODS: Lipid droplet accumulation in PSCs was used to observe differences in PSC activity and a new high-throughput screening platform that quantified lipid droplets in PSCs was established. A library of 3398 Food and Drug Administration-approved drugs was screened by this platform. Validation assays were performed in vitro and in vivo. RESULTS: Thirty-two compounds were finally selected as candidate compounds by screening. These compounds decreased α-smooth muscle actin expression and inhibited autophagic flux in PSCs in vitro. Among the candidates, three drugs selected for validation assays inhibited the proliferation and migration of PSCs and invasion of cancer cells by disrupting tumor-stromal interactions. Production of extracellular matrix molecules was also decreased significantly by this treatment. In vivo testing in xenograft models showed that dopamine antagonist zuclopenthixol suppressed tumor growth; this suppression was significantly increased when combined with gemcitabine. CONCLUSIONS: A new screening platform that focused on the morphological features of PSCs was developed. Candidate drugs from this screening suppressed PSC activation and tumor growth. This screening system may be useful to discover new compounds that attenuate PSC activation.

Proton pump inhibitors may hinder hypophosphatemic effect of lanthanum carbonate, but not of ferric citrate hydrate or sucroferric oxyhydroxide, in hemodialysis patients.

Because end-stage renal disease patients undergoing hemodialysis frequently take acid suppressants for the treatment or prevention of gastrointestinal diseases, it is important to clarify the drug-interactions between acid suppressants and phosphate binders on the control of serum phosphate levels. In the present study, we examined whether the phosphate-lowering effects of three phosphate binders, lanthanum carbonate (LC), ferric citrate hydrate (FCH), and sucroferric oxyhydroxide (SFOH), were affected by proton pump inhibitors (PPIs) in maintenance hemodialysis patients. Laboratory data for 71 patients who had been newly prescribed one of the three phosphate binders were examined. LC at a dosage of 500 ± 217 mg/day significantly decreased serum phosphate levels by -18% in the absence of a PPI (n = 9), while a dosage of 700 ± 230 mg/day only decreased it by -3% in the presence of a PPI (n = 10). Thus, the efficacy of LC in reducing serum phosphate levels was significantly hindered by the presence of PPIs. FCH significantly decreased serum phosphate levels by -18% in the absence of a PPI (n = 7, FCH: 571 ± 189 mg/day) and by -17% in the presence of a PPI (n = 20, FCH: 638 ± 151 mg/day). The decrease in serum phosphate levels by SFOH (393 ± 197 mg/day) was -7% in the absence of a PPI (n = 7), and SFOH at a dosage of 556 ± 316 mg/day significantly decreased serum phosphate levels by -13% in the presence of a PPI (n = 18). These results suggest that the phosphate-lowering effect of LC, but not of FCH or SFOH, is diminished in the presence of PPIs in hemodialysis patients.

S100P regulates the collective invasion of pancreatic cancer cells into the lymphatic endothelial monolayer.

Lymph node metastasis is an independent prognostic factor in pancreatic cancer. However, the mechanisms of lymph node colonization are unknown. As a mechanism of lymphatic metastasis, it has been reported for other types of cancer that spheroids from tumor cells cause circular chemorepellent­induced defects (CCIDs) in lymphatic endothelial monolayers. In pancreatic cancer, such mechanisms of metastasis have not been elucidated. The present study evaluated the involvement of this new mechanism of metastasis in pancreatic cancer and investigated the associated factors. In human pancreatic cancer tissue, it was observed that clusters of cancer cells penetrated the wall of lymphatic ducts around the primary tumor. An in vitro co­culture system was then used to analyze the mechanisms of tumor cell­mediated disruption of lymphatic vessels. Time­lapse microscopic imaging revealed that spheroids from pancreatic cancer cells caused circular defects in lymphatic endothelial monolayers. CCID formation ability differed depending on the cell line. Neither aggregation of spheroids nor adhesion to lymphatic endothelial cells (LECs) exhibited a significant correlation with this phenomenon. The addition of supernatant from cultured cancer cells enhanced CCID formation. Microarray analysis revealed that the expression of S100 calcium binding protein P (S100P) was significantly increased when LECs were treated with supernatant from cultured cancer cells. Addition of a S100P antagonist significantly suppressed the migration of LECs and CCID formation. The present findings demonstrated that spheroids from pancreatic cancer cells caused circular defects in lymphatic endothelial monolayers. These CCIDs in pancreatic cancer were partly regulated by S100P, suggesting that S100P may be a promising target to inhibit lymph node metastasis.

Endoscopic Transpapillary Pancreatic Duct Stent Placement for Symptomatic Peripancreatic Fluid Collection Caused by Clinically Relevant Postoperative Pancreatic Fistula After Distal Pancreatectomy.

This study aimed to evaluate the safety and efficacy of endoscopic transpapillary pancreatic duct stent placement (ETPS) for symptomatic peripancreatic fluid collection caused by postoperative pancreatic fistula (POPF) after distal pancreatectomy (DP). ETPS was also compared with percutaneous drainage (PTD). Retrospectively 38 patients were studied who developed clinically relevant POPF. Of 38 patients, 4 underwent PTD and 11 underwent ETPS. Technical and clinical success rates of ETPS (100% and 91%, respectively) were comparable with PTD (100% and 75%, respectively). The tip of a pancreatic stent was placed over the pancreatic stump in 4 patients and draining of pus through the pancreatic stent was observed. The hospital stay after DP and the interval from intervention to discharge were significantly shorter in the ETPS group than in the PTD group. ETPS is safe and successful for managing peripancreatic fluid collection caused by POPF after DP and should be considered as a therapeutic option.

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

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.

Cancer-associated acinar-to-ductal metaplasia within the invasive front of pancreatic cancer contributes to local invasion.

The pancreas is an organ prone to inflammation, fibrosis, and atrophy because of an abundance of acinar cells that produce digestive enzymes. A characteristic of pancreatic cancer is the presence of desmoplasia, inflammatory cell infiltration, and cancer-associated acinar atrophy (CAA) within the invasive front. CAA is characterized by a high frequency of small ducts and resembles acinar-to-ductal metaplasia (ADM). However, the clinical significance of changes in acinar morphology, such as ADM with acinar atrophy, within the tumor microenvironment remains unclear. Here, we find that ADM within the invasive front of tumors is associated with cell invasion and desmoplasia in an orthotopic mouse model of pancreatic cancer. An analysis of resected human tumors revealed that regions of cancer-associated ADM were positive for TGFα, and that this TGFα expression was associated with primary tumor size and shorter survival times. Gene expression analysis identified distinct phenotypic profiles for cancer-associated ADM, sporadic ADM and chronic pancreatitis ADM. These findings suggest that the mechanisms driving ADM differ according to the specific tissue microenvironment and that cancer-associated ADM and acinar atrophy contribute to tumor cell invasion of the local pancreatic parenchyma.

Hepatic inflammatory pseudotumor associated with primary biliary cholangitis and elevated alpha-fetoprotein lectin 3 fraction mimicking hepatocellular carcinoma.

BACKGROUND: Hepatic inflammatory pseudotumor (IPT) is a rare benign lesion. Because there is no specific laboratory marker or radiographic appearance, the majority of reported cases of hepatic IPT have been diagnosed after surgery or at autopsy. The etiology of hepatic IPT remains unclear but several mechanisms have been postulated such as infection or immune reaction. CASE PRESENTATION: A 79-year-old woman had been seeing her family doctor for hypertension, and she had been diagnosed with liver dysfunction for about 10 years. She continued attending follow-ups because of her drinking habit. Two months before her visiting our institution, further elevation of hepatobiliary enzymes was noted, and abdominal ultrasonography showed a hepatic tumor 4 cm in diameter in the lateral segment, so she was referred to our hospital. Hepatocellular carcinoma (HCC) was suspected because alpha-fetoprotein (102 ng/ml) (AFP) and lectin 3 (L3) fraction (85.4%) were elevated and the appearance on enhanced computed tomography was not inconsistent with HCC. Thus, we performed laparoscopic hepatectomy. She recovered uneventfully and was discharged on postoperative day 7. Pathological diagnosis revealed that the tumor was hepatic IPT and that the background liver condition was primary biliary cholangitis (PBC). AFP and L3 fraction decreased to normal ranges after surgery. CONCLUSIONS: In 7 of 29 patients (24.1%) with reported cases of tumor markers in liver IPT, carbohydrate antigen 19-9 was elevated and AFP was elevated in 2 of 58 patients (3.4%). AFP is also frequently elevated in benign liver diseases such as hepatitis and liver cirrhosis, and L3 fraction has been used as a tumor marker for HCC with high specificity. To our knowledge, this is the first report of a case diagnosed with liver IPT in which AFP and L3 fraction increased before surgery and decreased to the normal range after resection. This confirms the rarity of hepatic IPT associated with PBC and elevated AFP and L3 fraction.

The validity of the surgical indication for intraductal papillary mucinous neoplasm of the pancreas advocated by the 2017 revised International Association of Pancreatology consensus guidelines.

PURPOSE: This study was performed to evaluate the surgical indication for intraductal papillary mucinous neoplasm (IPMN) advocated by the 2017 revised International Association of Pancreatology consensus guidelines (IAPCG2017). METHODS: The medical records of 63 patients who underwent pancreatectomy for IPMN were retrospectively reviewed. RESULTS: Thirteen patients had main-duct IPMN, 25 had mixed IPMN, and 25 had branch-duct IPMN with frequencies of high-grade dysplasia or invasive carcinoma of 62, 24, and 28%, respectively. The sensitivity and specificity of high-risk stigmata for high-grade dysplasia or invasive carcinoma advocated by the IAPCG2017 were 90 and 67%, respectively. Of 17 patients with invasive carcinoma, all patients had high-risk stigmata, and 16 had an enhanced mural nodule (MN) of ≥ 5 mm. The sensitivity and specificity of a ≥ 5-mm enhanced MN for predicting invasive carcinoma were 94% and 87%, respectively. CONCLUSIONS: Introducing a size threshold for enhanced MNs into the assessment of high-risk stigmata increases the specificity without jeopardizing the sensitivity. The surgical indication for any type of IPMN may be determined using only a ≥ 5-mm enhanced MN. When the type of IPMN is classified strictly, about half of IPMNs are mixed type, and most are benign. The surgical indication for mixed IPMN should be reconsidered.

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.

Long-Term Outcomes After Pancreatectomy for Pancreatic Ductal Adenocarcinoma in Elderly Patients: Special Reference to Postoperative Adjuvant Chemotherapy.

BACKGROUND: The benefit of pancreatectomy for elderly patients with pancreatic ductal adenocarcinoma (PDAC) remains controversial. Moreover, adjuvant chemotherapy (AC) for elderly patients has not been fully evaluated. We investigated the long-term outcomes after pancreatectomy for PDAC in elderly patients with special reference to AC. METHODS: The medical records of 123 patients who underwent pancreatectomy for PDAC from 2007 to 2016 were retrospectively reviewed. The patients were divided into two groups: young (<75 years) and elderly patients (≥75 years). RESULTS: The study population comprised 91 young and 32 elderly patients. The postoperative clinical courses were not different between the two groups. AC was more frequently administered to young (85%) than elderly patients (66%; P = 0.04). The weekly dose of tegafur/gimeracil/oteracil potassium (S1) for AC was significantly lower in elderly (median 423 mg/m2) than young patients (median 491 mg/m2; P = 0.02). The prevalence of adverse events and the completion rate of AC were not significantly different between the two groups. There were no significant differences in recurrence-free survival (P = 0.73) or overall survival (P = 0.68) between the two groups in univariate analysis. Receipt of AC was not a significant independent factor for survival, and completion of planned AC was a significant independent factor for recurrence-free survival and overall survival in multivariate analysis. CONCLUSIONS: The benefit of pancreatectomy for PDAC was the same between young and elderly patients. Completion of planned AC was important, and lowered-dose AC using S1 for elderly patients might be safe and therapeutically useful.

Association of Maternal Factors with Perinatal Complications in Pregnancies Complicated with Diabetes: A Single-Center Retrospective Analysis.

OBJECTIVE: The aim of this study was to clarify the association of maternal factors with perinatal complications in pregnancies complicated with type 1 (T1D) or type 2 diabetes (T2D). METHODS: We conducted a retrospective chart review and enrolled 26 Japanese pregnant women with diabetes who received perinatal care at our hospital between 2008 and 2015. Perinatal complications were defined as one or more of the following: miscarriage, fetal death, fetal dysfunction, fetal structural anomaly, small-for-gestational age, large-for-gestational age (LGA), premature birth, neonatal hypoglycemia, pregnancy-induced hypertension (PIH), deterioration of maternal kidney function, and urgent Caesarean section (CS). The associations between perinatal complications and maternal factors were examined. RESULTS: Approximately 70% and 50% of women with T1D and T2D experienced perinatal complications, respectively. LGA, neonatal hypoglycemia, and urgent CS were major perinatal complications in women with T1D, while PIH and urgent CS were major complications in those with T2D. In women with T1D, pre-gestational HbA1c was significantly higher in women with perinatal complications than in those without. In women with T2D, pre-gestational body mass index was significantly higher in women with perinatal complications than in those without. CONCLUSIONS: These findings suggest that while pre-gestational glycemic control remains the most important issue in women with T1D, pre-gestational weight control in addition to glycemic control should be greater emphasized in women with T2D to reduce the risk of perinatal complications.

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.

Autophagy inhibition enhances antiproliferative effect of salinomycin in pancreatic cancer cells.

BACKGROUND: Salinomycin 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. METHODS: We 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. RESULTS: Salinomycin 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. CONCLUSIONS: Our 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.