Insulin-Like Growth Factor 1 Receptor Promotes the Growth and Chemoresistance of Pancreatic Cancer

Background

Insulin-like growth factor 1 receptor (IGF1R) plays important roles in the progression of pancreatic cancer. However, the underlying mechanism remains unclear.

Aims

The purpose of this study was to investigate the effects of IGF1R knockdown on the proliferation, apoptosis and chemosensitivity of pancreatic cancer cells, and explore the possible mechanisms.

Methods

Pancreatic cancer cells expressing IGF1R shRNA were established, and the cell proliferation, colony formation, and chemosensitivity to gemcitabine were examined in vitro. The activation of AKT and NF-κB was detected by Western blot analysis and luciferase assay, respectively. Xenograft mice models were established to evaluate the in vivo anti-tumor effects of IGF1R knockdown.

Results

IGF1R knockdown notably inhibited pancreatic cancer cell proliferation and colony formation, induced apoptosis, and inhibited xenograft tumor growth. Moreover, IGF1R knockdown significantly enhanced chemosensitivity to gemcitabine in pancreatic cancer cells, and this was correlated with the inhibition of PI3K/AKT and NF-κB pathways.

Conclusions

IGF1R knockdown suppresses tumor growth and enhances chemosensitivity in pancreatic cancer via the inhibition of PI3K/AKT and NF-κB pathways, and is a promising approach to overcome the chemoresistance of pancreatic cancer.     

The DJ-1 protein as a candidate biomarker in obstructive sleep apnea syndrome

Background

Oxidative stress has a central role in the pathophysiology of obstructive sleep apnea syndrome (OSAS). The DJ-1 protein functions as a sensor of oxidative stress, acting both as a reactive oxygen species scavenger (ROS) and an antioxidative response regulator. The aim of our study is to determine the serum levels of DJ-1 in OSAS patients and assess possible correlations with their clinical, demographical, and biochemical characteristics.

Methods

The study included 120 subjects from the Sleep Disorder Laboratory of the University Hospital of Thessaly (100 males vs 20 females, mean age 48?±?10, Apnea–Hypopnea Index (AHI) >5 episodes per hour of sleep). Subjects underwent full-night polysomnography (PSG) followed by morning blood sampling. Serum DJ-1 levels were determined via ELISA kits. Statistical analysis was performed using SPSS 19.

Results

The median DJ-1 levels were 56.7 ng/mL (IQR, 34.9–99.3 ng/mL). Statistically significant correlations were detected between DJ-1’s levels and AHI (Spearman’s rho?=?0.189, P?=?0.04), Desaturation Index (DI; Spearman’s rho?=?0.239, P?=?0.012), and serum low-density lipoprotein (LDL) (Spearman’s rho?=??0.205, P?=?0.042).

Conclusions

DJ-1 may be a useful biomarker in OSAS due to its correlations with AHI and DI. The correlation with serum LDL warrants further investigation regarding possible implications in OSAS patients’ cardiovascular comorbidities.     

LPS Induced miR-181a Promotes Pancreatic Cancer Cell Migration via Targeting PTEN and MAP2K4

Background

Pancreatic cancer is aggressive; 80–90 % of pancreatic cancer patients have already developed metastatic cancer at the time of diagnosis. Inflammation has been shown to facilitate pancreatic cancer migration. The toll-like receptors (TLRs) pathway is an important inflammatory signal transduction pathway. However, the mechanism of inflammation pathway to induce pancreatic cancer migration is unclear.

Aims

The purpose of this study was to investigate how inflammation affects pancreatic cancer migration.

Methods

RT-PCR was used to detect the TLRs expression files in pancreatic cancer cells and tissues. Pancreatic cancer cells migration was assessed after treatment with TLR4 agonist, lipopolysaccharide (LPS). Moreover, two tumor suppressors, PTEN and MAP2K4, were detected. Then we predicted and proved the miRNA which targeted PTEN and MAP2K4.

Results

We found that the expression of TLR4 was increased in pancreatic cancer cells and tissues. After treatment with LPS, the migration of pancreatic cancer cells was increased and the protein levels of two tumor suppressors, PTEN and MAP2K4, were inhibited. To investigate the possible mechanism, we checked the expression of miR-181a. The result showed that miR-181a was decreased by LPS. Furthermore, we predicted and confirmed that both PTEN and MAP2K4 were miR-181a targets. Pancreatic cancer tissues analysis showed that PTEN and MAP2K4 were all negatively correlated with miR-181a.

Conclusions

These results suggest that the LPS-TLR4-miR-181a signaling pathway plays a significant role in pancreatic cancer invasion and progression.     

Effect of type 1 insulin-like growth factor receptor targeted therapy on chemotherapy in human cancer and the mechanisms involved

Introduction

Chemotherapy is administered only to patients with advanced cancers, typically to modest avail. Hence, the search for innovative approaches to treat cancer is growing rapidly. One such approach involves targeting molecular pathways identified as encouraging tumor growth and maintenance, particularly the type 1 insulin-like growth factor (IGF-1) and its receptor (IGF-1R) pathway that is important in conferring chemoresistance.

Materials and Methods

This study focuses on IGF-1R targeted therapy, which will enhance chemotherapy efficacy, through reviewing recent literature from PubMed and Medline databases.

Conclusion

This review examines data and strategies addressing an approach conquering chemoresistance through the combination of IGF-1R targeted therapy and chemotherapy in cancer patients, as well as the mechanisms by which IGF-1R acts as a target. This will impact on future research on treatment selection, thereby improving patient prognosis.     

Matrix Metalloproteinase-14 Is a Negative Prognostic Marker for Patients with Gastric Cancer

Background

Matrix metalloproteinase-14 (MMP-14) has been considered to play an important role in invasion and metastasis of human solid tumor.

Aim

The present study aimed to investigate the association of MMP-14 with overall survival in human gastric cancer.

Methods

Gastric cancer and adjacent normal specimens were collected from 205 patients who had not received neoadjuvant chemotherapy. MMP-14 expression was investigated by immunohistochemistry assay and staining evaluation results were analyzed statistically in relation to overall survival of patients.

Results

MMP-14 expression proved to be increased in gastric cancer compared with that in normal tissues. It was also proved that MMP-14 expression was associated with tumor invasion, metastasis, and TNM stage while no correlations were detected between MMP-14 expression and age, sex, differentiation status, or Lauren’s classification. Moreover, patients with gastric cancer of MMP-14-positive expression tend to have worse overall survival compared with those with MMP-14 negative expression.

Conclusions

The present study confirmed the over-expression of MMP-14 in human gastric cancer and its association with tumor progression. It also provided the first evidence that MMP-14 expression in gastric cancer was an independent negative prognostic factor of patients.     

Identification of IMPDH2 as a tumor-associated antigen in colorectal cancer using immunoproteomics analysis

Background and aims

Sera from cancer patients contain tumor-specific autoantibodies directly against antigenic proteins. The identification of tumor autoantigens may have utility in cancer diagnosis, prognosis, and therapy. In this study, we used immunoproteomics analysis to identify tumor proteins that elicit humoral response in colorectal cancer (CRC).

Materials and methods

The CRC cell line HCT116 was used as a source of proteins for two-dimensional polyacrylamide gel electrophoresis and subsequent Western blot analysis in which individual serum from patients with CRC was analyzed for autoantibodies. Proteins that specifically react with sera from cancer patients were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis. In addition, the selected protein expression in tumor tissues collected from 40 patients with CRC were assessed by immunohistochemistry.

Results

An autoantibody against inosine monophosphate dehydrogenase II (IMPDH2) identified by mass spectrometry was detected in eight out of 25 patients with CRC. However, none of the 15 healthy controls demonstrated autoantibody to IMPDH2.The expression of IMPDH2 in tumor tissue was significantly higher in patients with CRC than that in healthy subjects.

Conclusions

The result confirmed that the immunoproteomics analysis holds considerable promise for the discovery of tumor-associated antigens. IMPDH2 may be a protein biomarker and novel therapeutic target in CRC.     

Serum tumor antigen REG4 as a diagnostic biomarker in pancreatic ductal adenocarcinoma

Background and Aims

Serum biomarkers for the early detection of pancreatic cancer are not currently available. We evaluated the usefulness of a novel serum marker, REG4, in the diagnosis of pancreatic cancer, as compared to carbohydrate antigen (CA) 19-9.

Methods

We collected pretherapeutic sera from 92 patients with pancreatic cancer, as well as sera from 28 patients with other pancreatic tumors, 11 patients with pancreatitis, and 69 healthy controls. Serum levels of REG4 were measured using a standard sandwich enzyme-linked immunosorbent assay (ELISA).

Results

Compared with healthy controls, serum levels of REG4 were higher in pancreatic cancer patients (P < 0.001), and in patients with pancreatitis (P < 0.001). Receiver operating characteristic (ROC) analysis indicated that serum REG4 performed better than serum CA19-9 for distinguishing patients with pancreatic cancer from healthy controls [areas under the curve (AUC) for REG4 and CA19-9 were 0.922 and 0.884, respectively]. When we validated the study, the sensitivity of REG4 for pancreatic cancer was 94.9%, specificity was 64.0%, and accuracy was 77.5% for the REG4 cutoff value of 3.49 ng/ml. No correlation was seen between serum REG4 and CA19-9 levels, with the sensitivity, specificity, and accuracy of the combined markers reaching 100.0, 60.0, and 77.5%, respectively. No significant differences were seen among any stages of pancreatic cancer. In surgical specimens, immunohistochemical analysis found a correlation between serum REG4 levels and REG4 expression in pancreatic cancers.

Conclusions

REG4 is expressed in pancreatic cancer, and serum levels of REG4 offer a useful indicator for distinguishing between patients with pancreatic cancer and healthy subjects. Serum REG4 has potential for use as a screening serum marker for pancreatic cancers, including early-stage cancers.     

AEG-1 Is a Target of Perifosine and Is Over-Expressed in Gastric Dysplasia and Cancers

Background

Perifosine, an alkylphospholipid, is an Akt inhibitor which inhibits the growth of diverse cancer cells. We have reported its inhibitory effects on the growth of gastric cancer cells recently, but its molecular mechanisms are still largely unknown.

Aims

The purpose of this study was to investigate the effect and regulatory mechanism of perifosine in gastric cancer.

Methods

Cell viability was determined by sulforhodamine B assay after transiently transfected with AEG-1 specific siRNAs. qRT-PCR and western blot assay were used to determine the mRNA expression and proteins levels of cell signaling molecules examined. Immunohistochemistry was used to detect the AEG-1 expression in 87 gastric carcinomas, 60 dysplasia, and 47 normal gastric mucosa.

Results

Perifosine decreased AEG-1 gene expression along with inhibition of Akt/GSK3β/C-MYC signaling pathway. Knockdown of AEG-1 using siRNA led to significant down-regulation of cyclin D1 expression at both mRNA level and protein level, and inhibited the growth of gastric cancer cells. AEG-1 expression was elevated in gastric dysplasia and cancer tissues compared to normal gastric mucosa (P < 0.01). AEG-1 over-expression correlated with diffuse type of gastric cancer and advanced tumor stages.

Conclusions

Perifosine inhibits the growth of gastric cancer cells possibly through inhibition of the Akt/GSK3β/C-MYC signaling pathway—mediated down-regulation of AEG-1 that subsequently down-regulated cyclin D1. AEG-1 may play an important role in the carcinogenesis and progression of gastric cancer and could be a therapeutic target of perifosine.     

Triptolide triggers the apoptosis of pancreatic cancer cells via the downregulation of Decoy receptor 3 expression

Purpose

Triptolide (TPL) is a diterpenoid triepoxide that effectively induces apoptosis in a wide variety of cancer cells. However, the detailed mechanism by which TPL activates caspase cascade remains elusive. This study aimed to examine the antitumor effects of TPL against pancreatic cancer and investigate the underlying mechanism.

Methods

Cell proliferation was evaluated by sulforhodamine B assay. The apoptosis was evaluated by caspase activity assay, Western blot and flow cytometry. DcR3 level was measured by ELISA. AsPC-1 xenografts were established to compare the in vivo antitumor effects of TPL and Gemcitabine.

Results

TPL inhibited the proliferation and induced the apoptosis of pancreatic cancer cells in a dose- and time-dependent manner. TPL also inhibited DcR3 expression in a dose- and time-dependent manner. siRNA-mediated DcR3 knockdown sensitized pancreatic cancer cells to TPL-induced apoptosis. In vivo, DcR3 siRNA significantly enhanced TPL-induced apoptosis and tumor growth inhibition. Moreover, TPL showed less toxicity compared to Gemcitabine in mice model.

Conclusions

TPL induces the apoptosis of pancreatic cancer cells via the downregulation of DcR3 expression and has the potential as an effective agent against pancreatic cancer.     

Reverse-Phase Protein Array Analysis to Identify Biomarker Proteins in Human Pancreatic Cancer

Background

Pancreatic cancer is the fourth leading cause of cancer death in the United States. The high mortality rate of patients with pancreatic cancer is primarily due to the difficulty of early diagnosis and a lack of effective therapies. There is an urgent need to discover novel molecular targets for early diagnosis and new therapeutic approaches to improve the clinical outcome of this deadly disease.

Aim

We utilized the reverse-phase protein assay (RPPA) to identify differentially expressed biomarker proteins in tumors and matched adjacent, normal-appearing tissue samples from 15 pancreatic cancer patients.

Methods

The antibody panel used for the RPPA included 130 key proteins involved in various cancer-related pathways. The paired t test was used to determine the significant differences between matched pairs, and the false discovery rate-adjusted p values were calculated to take into account the effect of multiple comparisons.

Results

After correcting for multiple comparisons, we found 19 proteins that had statistically significant differences in expression between matched pairs. However, only four (AKT, β-catenin, GAB2, and PAI-1) of them met the conservative criteria (both a q value <0.05 and a fold-change of ≥3/2 or ≤2/3) to be considered differentially expressed. Overexpression of AKT, β-catenin, and GAB2 in pancreatic cancer tissues identified by RPPA has also been further confirmed by western blot analysis. Further analysis identified several significantly associated canonical pathways and overrepresented network functions.

Conclusion

GAB2, a newly identified protein in pancreatic cancer, may provide additional insight into this cancer’s pathogenesis. Future studies in a larger population are warranted to further confirm our results.     

Activation of alpha-smooth muscle actin-positive myofibroblast-like cells after chemotherapy with gemcitabine in a rat orthotopic pancreatic cancer model

Background

To investigate the behavior of activated pancreatic stellate cells (PSCs), which express alpha-smooth muscle actin (α-SMA), and pancreatic cancer cells in vivo, we examined the expression of α-SMA-positive myofibroblast-like cells in pancreatic cancer tissue after treatment with gemcitabine (GEM) using a Lewis orthotopic rat pancreatic cancer model.

Methods

The effect of GEM on DSL-6A/C1 cell proliferation was determined by cell counting method. The orthotopic pancreatic cancer animals were prepared with DSL-6A/C cells, and treated with GEM (100 mg/kg/weekly, for 3 weeks). At the end of treatment, α-SMA expression, fibrosis, transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF) were evaluated by histopathological and Western blot analyses.

Results

DSL-6A/C1 cell proliferation was significantly reduced by co-culturing with GEM in vitro. Survival time of pancreatic cancer animals (59.6 ± 13.4 days) was significantly improved by treatment with GEM (89.6 ± 21.8 days; p = 0.0005). Alpha-SMA expression in pancreatic cancer tissue was significantly reduced after treatment with GEM (p = 0.03), however, there was no significant difference in Sirius-red expression. Expression of VEGF was significantly reduced by GEM treatment, but the expression of TGF-β1 was not inhibited.

Conclusion

GEM may suppress not only the tumor cell proliferation but also suppress PSCs activation through VEGF reduction.     

Pancreatic cancer causing acute pancreatitis: a comparative study with cancer patients without pancreatitis and pancreatitis patients without cancer

Background/purpose

Although pancreatic cancer produces upstream obstructive pancreatitis, acute pancreatitis is a less common manifestation of pancreatic cancer. This study aimed to clarify the subgroup of pancreatic cancer patients who present with an episode of acute pancreatitis (Group I) in comparison with a matched group of pancreatic cancer patients without pancreatitis (Group II) and another group of acute pancreatitis patients without pancreatic cancer (Group III).

Methods

This was a retrospective comparative study of 18 patients in Group I, 300 patients in Group II and 141 patients in Group III.

Results

The mean age of Group I was 63.7 years and the male to female ration was 1:0.3. Serum CA 19-9 levels were elevated in 80 %. The main pancreatic duct was incompletely obstructed in 7 patients. There were no significant differences in location of tumor, clinical stage, resection rate and survival months between Group I and II. Acute pancreatitis secondary to pancreatic cancer was more likely to be mild (94 vs. 72 %, p < 0.05) and relapsed (39 vs. 16 %, p < 0.05) compared with Group III.

Conclusions

Anatomic evaluation of the pancreas should be performed in patients with acute pancreatitis with no obvious etiology, even if the pancreatitis is mild, to search for underlying malignancy.     

Adiponectin Inhibits Murine Pancreatic Cancer Growth

Background

Adiponectin is an adipose tissue-derived secretory hormone whose plasma concentrations are lower in obese individuals. Obesity is a risk factor for the development and growth of pancreatic cancer, and hypoadiponectinemia was suggested to be involved in the growth of Pan02 murine pancreatic cancer cells that were inoculated into the flanks of congenitally obese mice.

Aim

The aim of this study was to clarify the role of adiponectin in the growth of pancreatic cancer cells.

Methods

We examined the effect of adiponectin on the growth of Pan02 cells using recombinant adiponectin and adiponectin knockout mice.

Results

The in vitro treatment of Pan02 cells with adiponectin inhibited cellular proliferation that was accompanied by increased apoptosis and caspase-3 and caspase-7 activities. Transplantation of Pan02 cells into the pancreas of knockout mice resulted in a larger tumor volume with fewer terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells compared with wild-type mice.

Conclusions

The results indicate that adiponectin directly suppresses the proliferation of Pan02 cells.     

Cholecystokinin Mediates Progression and Metastasis of Pancreatic Cancer Associated with Dietary Fat

Background

Obesity and dietary fat are associated with increased risk of several malignancies including pancreatic cancer. The incidence of pancreatic cancer is increased in countries that consume diets high in fat.

Aim

The purpose of this study was to assess the relationship and mechanism of action between dietary fat and endogenous cholecystokinin (CCK) on pancreatic tumor growth and metastasis in an immunocompetent animal model.

Methods

C57BL/6 mice were placed on regular, low-fat, or high-fat diets for 8 weeks before establishment of Panc-02 orthotopic pancreatic tumors. Mice were then treated with a CCK-A receptor antagonist, devazepide, or vehicle for an additional 2.5 weeks. Pancreas tumors were weighed and metastases counted. Blood CCK levels were measured by radioimmunoassay (RIA). Tissues were examined histologically and studied for genes associated with metastasis by RT-PCR array. Effects of the CCK antagonist on Panc-02 cells invasiveness was assessed in a Matrigel invasion assay.

Results

Mice that received the high-fat diet had larger tumors and tenfold higher serum CCK levels by RIA compared to normal diet controls (p < 0.01). Pancreatic tumors in high-fat diet mice treated with the antagonist had fewer intravascular tumor emboli and metastases compared to controls. The reduction in tumor emboli correlated with decreased vascular endothelial growth factor-A (VEGF-A) expression in tumors (p < 6 × 10^?9). In vitro invasiveness of Panc-02 cells also was reduced by CCK-A receptor antagonist treatment (p = 1.33 × 10^?6).

Conclusion

CCK is a mediator of dietary fat-associated pancreatic cancer. CCK is also involved in the invasiveness of pancreatic tumors through a mechanism involving VEGF-A.     

Human equilibrative nucleoside transporter 1 expression is a strong independent prognostic factor in UICC T3-T4 pancreatic cancer patients treated with preoperative gemcitabine-based chemoradiotherapy

Background/purpose

We aimed to determine the relationship between the intratumoral expression of human equilibrative nucleoside transporter (hENT1), the main gemcitabine transporter into cells, and the outcome of gemcitabine-based chemoradiotherapy (Gem-CRT) in patients with International Union Against Cancer (UICC) T3–T4 pancreatic adenocarcinoma.

Methods

The expressions of hENT1, thymidylate synthase (TS), and dihydropyrimidine dehydrogenase were immunohistochemically analyzed using the resected specimens from 55 patients (T3, 38 and T4, 17) who had received curative-intent resection after Gem-CRT.

Results

The status of hENT1 expression (positive in 39 and negative in 16) was significantly associated with “clinical efficacy” (defined as more than 50% reduction of the serum carbohydrate antigen [CA] 19-9 level with stable disease [SD] or partial response [PR] according to the Response Evaluation Criteria in Solid Tumors [RECIST]) for Gem-CRT. The 1- and 3-year overall survival (OS) rates were significantly higher in the positive hENT1 expression group (82.9, 39.5%) than in the negative expression group (42.9, 14.3%) (p?=?0.0037). According to combination analysis of hENT1 and TS expressions, the 1- and 3-year OS rates were significantly higher in the positive-low combination (89.1, 51.0%) group than in the negative-high group (66.7, 0%) (p?=?0.023). Multivariate analysis revealed that positive hENT1 expression and R0 resection were significant prognostic factors for OS.

Conclusions

The hENT1 expression in pancreatic adenocarcinoma strongly influences the outcome of preoperative Gem-CRT treatment. This biomarker could become a useful predictor of therapeutic effect for gemcitabine-based therapy in pancreatic cancer patients.     

Resveratrol plays dual roles in pancreatic cancer cells

Purpose

Although the potential anticancer effect of resveratrol (RSV) on pancreatic cancer has been reported, its mechanism was not fully understood. The role of vascular endothelial growth factor B (VEGF-B) in cancer remains controversial. Herein, we aimed to examine whether the anticancer effect of RSV was related to the VEGF-B.

Methods

The effect of RSV on pancreatic cancer cell line (capan-2 cells) was evaluated by CCK-8 assay, Hoechst 33342 staining, and flow cytometry. The mRNA level of VEGF-B was measured by real-time PCR. VEGF-B expression was knockdown by small interfering RNA (siRNA).The protein levels of VEGF-B, glycogen synthase kinase-3 beta (GSK-3β), and Bax were measured by Western blot.

Results

Resveratrol treatment inhibited tumor growth, induced apoptosis, and up-regulated Bax expression in capan-2 cells. The mRNA and protein levels of VEGF-B were up-regulated after RSV treatment. However, VEGF-B siRNA treatment increased the apoptotic rate, and inhibited tumor activator GSK-3β, while Bax expression was not affected. The combination of RSV and VEGF-B siRNA showed significantly higher apoptotic rate in comparison with RSV or VEGF-B siRNA mono-treatment group.

Conclusions

Resveratrol plays dual roles in pancreatic cancer: as a tumor suppressor via the up-regulation of Bax; as a tumor activator via the up-regulation of VEGF-B; and the anticancer effect of RSV is much stronger than the cancer promotion effect. The combination of RSV with pharmacological inhibitor of VEGF-B might, therefore, be a promising modality for clinical pancreatic cancer therapy.