The Ras-ERK signaling pathway regulates acetylated activating transcription factor 2 via p300 in pancreatic cancer cells.

BACKGROUND: Activating transcription factor 2 (ATF2) regulates the expression of downstream target genes and is phosphorylated by the Ras-extracellular-signal-regulated kinase (ERK) pathway. Acetylation of ATF2 is necessary for this type of regulation. However, the molecular mechanism by which the Ras-ERK pathway mediates the regulation of acetylated ATF2 is unknown. This study investigates the mechanism of Ras-ERK pathway-mediated regulation of acetylated ATF2 in maintaining the characteristic phenotype of pancreatic cancer cells. METHODS: This study was carried out using ASPC-1 and BXPC-3 pancreatic cancer cell lines transfected with the double mutant RasG12V/T35S. The levels of phosphorylated ERK1/2 were measured to establish the activated Ras-ERK pathway. The regulation of acetylated ATF2 was examined by detecting the protein level using western blotting, and the effects on cancer cell phenotype were measured using cell viability, proliferation, migration, and apoptosis assays. Also, chromatin immunoprecipitation (ChIP) assays were used to measure the effect on respective downstream target genes. RESULTS: The results showed that RasG12V/T35S reduced the level of acetylated ATF2 in ASPC-1 and BXPC-3 cells. Compared to wild-type ATF2, the mutant ATF2K357Q (which mimics the irreversible acetylated form of ATF2) reduced the cancer cell phenotype and showed decreased enrichment on target genes upon transfection with Ras. Moreover, the level of acetylated ATF2 was regulated by the degradation of p300 through E3 ubiquitin ligase mouse double minute 2 homolog (MDM2). CONCLUSIONS: Activation of the Ras-ERK pathway regulates acetylated ATF2 through degradation of p300 via a proteasome-dependent pathway, which alters the transcription of downstream target genes responsible for the cancer cell phenotype.

The Ras-ERK1/2 signaling pathway regulates H3K9ac through PCAF to promote the development of pancreatic cancer.

AIMS: The regulation of the Ras-ERK pathway is the crucial point in pancreatic carcinogenesis, and the Ras kinase is an essential regulatory upstream signal molecule of the ERK1/2 pathway. H3K9ac is a vital histone modification, but its specific role in pancreatic cancer remains unclear. This research aims to study whether the modification level of H3K9ac can regulate the characteristic phenotype of the pancreatic cancer cells by affecting the downstream expression, proliferation, migration, and other related genes. MAIN METHODS: The RasG12V/T35S were used to transfect pancreatic cancer cells, and the levels of phosphorylated ERK1/2 and H3K9ac were detected by western blotting. The colony formation assay, transwell assay, and chromatin immunoprecipitation assay were used to study cell viability, migration, and the downstream genes of the ERK1/2 pathway. KEY FINDINGS: The results showed that Ras ERK1/2 reduced H3K9ac expression in ASPC-1 cells, and H3K9ac significantly repressed the viability of cells, colony formation, and ASPC-1 cell movement induced by Ras ERK1/2. Besides, HDAC1 silencing increased H3K9ac expression, and changed the effect of Ras ERK1/2 on ASPC-1 cells proliferation, its movement, and mRNAs of ERK1/2 downstream genes. Moreover, Ras ERK1/2 inhibited H3K9ac expression by the degradation of PCAF via MDM2. SIGNIFICANCE: Ras ERK1/2 promotes pancreatic carcinogenesis cell movement, through down-regulating H3K9ac via MDM2 mediated PCAF degradation.

Oncogenic miR-23a in Pancreatic Ductal Adenocarcinogenesis Via Inhibiting APAF1.

BACKGROUND: miR-23a, which participates in invasion of pancreatic ductal adenocarcinoma cells into the mesothelial barrier, is a critical regulator in many cancers. It, however, is still unknown whether miR-23a regulates pancreatic cell proliferation and apoptosis or not. AIMS: We sought to investigate the role of miR-23a in regulation of pancreatic cell proliferation and apoptosis. METHODS: miRNA, mRNA, and protein expressions were determined by qRT-PCR and Western blot, respectively. Dual-luciferase reporter assay was used in detection for binding ability of miR-23a to APAF1. Ectopic miR-23a and APAF 1 were introduced to pancreatic cells, and their roles in proliferation and apoptosis were detected by MTT, colony formation, and apoptosis assays, respectively. RESULTS: Up-regulation of miR-23a and down-regulation of APAF 1 were found in pancreatic ductal cancer, respectively. miR-23a significantly inhibited the luciferase activity by targeting APAF 1 3'UTR. Ectopic miR-23a significantly suppressed the APAF 1 gene expression in pancreatic cancer cells. Similar to siAPAF1, miR-23a significantly promoted pancreatic cancer cell proliferation and repressed apoptosis. Furthermore, miR-23a inhibitor and exogenous APAF 1 could recover the effects. CONCLUSIONS: It is suggested that miR-23a, acting as an oncogenic regulator by directly targeting APAF 1 in pancreatic cancer, is a useful potential biomarker in diagnosis and treatment of pancreatic cancer.

Diagnosis and treatment of pancreatic metastases in 22 patients: a retrospective study.

BACKGROUND: Pancreatic metastases (PMs) are rare and lack of guidelines for diagnosis and treatments .The aim of this study is to explore the diagnosis, treatment, and prognosis of pancreatic metastases. METHODS: Twenty-two patients with pancreatic metastases who had been hospitalized at the First Affiliated Hospital of China Medical University from October 1980 to October 2012 were included in the present retrospective study. Seven patients had gastric cancer, five had colon cancer, two each had lung and liver cancer, and one each had bladder cancer, gallbladder cancer, breast cancer, nasopharyngeal cancer, renal cell carcinoma, and carcinoid. RESULTS: No specific syndrome or imageological change was found for the pancreatic metastases. The most common symptoms were abdominal pain and jaundice. Hypo-echoic lesions with well-defined margins were found on ultrasonic examinations, and low-density lesions with heterogeneous enhancement were identified in CT images. Nineteen of the 22 received treatment. Three of the 8 patients (34.1%) that had undergone operation experienced complications, but all patients recovered after conventional treatment. Follow-up studies were performed for 17 patients (77.3%), and the median survival time from the diagnosis of pancreatic metastases was 13.2 months (range, 2 to 68 months). Of the five patients who underwent radical resection, one was lost to follow-up, one died at fifteen months postoperation, and the other three are still alive and free from disease (disease-free survival ranging from five to thirty-three months from the diagnosis of the pancreatic metastases). CONCLUSION: Pancreatic metastases are rare lesions with no specific symptoms. Radical resection should be performed if possible; however, aggressive treatment should be performed for unresectable pancreatic metastases.

Hepatobiliary cystadenoma and cystadenocarcinoma: a single center experience.

AIMS AND BACKGROUND: Hepatobiliary cystadenoma and cystadenocarcinoma are rare cystic lesions of the liver. The aim of the study was to discuss the clinical features, diagnostic methods and surgical treatment of hepatobiliary cystadenoma and cystadenocarcinoma in our hospital. METHODS: Six patients with hepatobiliary cystadenomas and four with hepatobiliary cystadenocarcinomas were evaluated. We collected detailed clinical data, and all patients were followed. RESULTS: Three patients of the 6 with cystadenomas and 2 patients of the 4 with cystadenocarcinomas had marked elevation of CA19-9 (average, 707.0 U/ml and 1078.5 U/ml, respectively). CT scan with contrast revealed typical lesions in all 10 cases, i.e., cyst-occupying lesions with separations in the liver. All patients with hepatobiliary cystadenoma were treated by partial hepatectomy. None of them recurred at a mean follow-up of 40 months. Three patients with hepatobiliary cystadenocarcinoma underwent hepatectomy, without recurrence or metastasis at a mean follow-up of 32 months. CONCLUSIONS: Tumor markers (CA19-9) and imaging findings may be helpful for an early diagnosis. Complete resection is still the best choice. Even for hepatobiliary cystadenocarcinoma, considering the low malignant grade, we suggest that for the best prognosis radical excision should be attempted.

Retropancreatic retroperitoneal tumors: a 30-year experience with 38 cases.

Retropancreatic retroperitoneal tumors (RRTs) are seldom encountered in clinical practice. The lack of characteristics on clinical presentation and imaging make preoperative diagnosis difficult and surgical management remains a challenge. This retrospective report surveys the presenting diagnosis and surgical management of 38 patients with RRTs presenting at our center between August 1981 and May 2012. Six patients were misdiagnosed on the basis of computerized tomography and one each by magnetic resonance imaging and magnetic resonance cholangiopancreatography. Tumors were localized posterior to the pancreatic head and uncinate process (n = 18); posterior to the neck and body of the pancreas (n = 9); or posterior to the body and tail of the pancreas (n = 11). Thirty-three patients underwent surgical resections. Operative approaches were chosen on the basis of tumor size and localization. The tumors were mostly commonly originating from neurogenic tissue (n = 16). There were 25 benign neoplasms (65.8%), 10 malignant tumors (26.3%), and three undefined tumors. The morbidity of postsurgical complications was 21 per cent (eight of 38). The number of patients who underwent follow-up was 21, and the mean follow-up time was 35 months (range, 2 to 90 months). Three patients died during follow-up. The morbility of local recurrence was 10.5 per cent (four of 38). Definitive diagnosis of RRTs is made at laparotomy. Complete resection remains the fundamental objective of disease management. Different operative approaches should be used according to tumor localization and size.

Silencing of the integrin-linked kinase gene suppresses the proliferation, migration and invasion of pancreatic cancer cells (Panc-1).

Integrin-linked kinase (ILK) is an ankyrin repeat-containing serine-threonine protein kinase that is involved in the regulation of integrin-mediated processes such as cancer cell proliferation, migration and invasion. In this study, we examined the effect of a lentivirus-mediated knockdown of ILK on the proliferation, migration and invasion of pancreatic cancer (Panc-1) cells. Immunohistochemical staining showed that ILK expression was enhanced in pancreatic cancer tissue. The silencing of ILK in human Panc-1 cells led to cell cycle arrest in the G0/G1 phase and delayed cell proliferation, in addition to down-regulating cell migration and invasion. The latter effects were mediated by up-regulating the expression of E-cadherin, a key protein in cell adhesion. These findings indicate that ILK may be a new diagnostic marker for pancreatic cancer and that silencing ILK could be a potentially useful therapeutic approach for treating pancreatic cancer.

[Indications, technique and efficacy of organ preserving pancreatectomy].

OBJECTIVE: To discuss the proper surgical management of pancreatic benign and low-grade malignant potential neoplasm. METHODS: The experience of 72 cases who accepted organ preserving pancreatectomy from January 1990 to May 2010 was analyzed retrospectively. There were 24 male and 48 female, aged from 15 to 68 years with mean age of 46 years. There were 9 cases underwent duodenum-preserving resection of the head of the pancreas, 29 cases underwent spleen-preserving distal pancreatectomy, 11 cases underwent middle segmental pancreatectomy, 23 cases underwent tumor extirpation of huge pancreatic cancer in pancreatic head and body. RESULTS: Pancreatic fistula and biliary fistula in 1 case respectively were cured among who accepted duodenum-preserving resection of the head of the pancreas. Pancreatic fistula was found in 3 cases who accepted spleen-preserving distal pancreatectomy. Pancreaticobiliary anastomotic bleeding in 1 case was cured among who accepted middle segmental pancreatectomy. Pancreatic fistula was found in 5 cases among who accepted tumor extirpation of huge pancreatic cancer in pancreatic head and body, and liver metastasis was found in 3 cases at 6, 12, 16 months after surgery respectively. CONCLUSIONS: Organ preserving pancreatectomy can obviously reduce operative injury to patients, its therapeutic effect is similar to that of classical operation, it is the first option of benign and low-grade malignant potential neoplasm.

[Macrocystic serous adenoma of the pancreas: a report of 5 cases].

OBJECTIVE: To investigate the diagnosis and treatment of macrocystic serous adenoma of the pancreas (MSAP). METHODS: The clinical data of 5 patients with MSAP treated from October 1999 to October 2009 were retrospectively analyzed. There were 5 female and 1 male. RESULTS: Of the 5 patients, 3 patients presented with abdominal pain and fullness, 1 patient with jaundice, 1 patient with asymptomatic. Ultrasonography and CT could manifest macrocystic lesion of the pancreas; all the lesion showed a well-defined border, internal septations, enhanced cyst walls, with no intramural (mural) nodule and papillary projections; the wall was smooth and thin in 4 cases; irregular lobulation could be observed in 3 cases, round or oval in 2 cases; 2 cases had pancreatic duct dilatation, 1 case had biliary duct dilatation. The tumors located in the pancreatic body and tail in 3 cases, the tumors located the pancreatic head in 2 cases. The sizes of the tumors ranged from 6.5 cm to 13.0 cm (mean, 8.8 cm). Five patients all accepted surgical intervention. The main postoperative complication was pancreatic fistula (2 cases); all the fistula was cured. Recurrence or metastasis were not found in 5 patient followed up postoperatively from 8 to 35 months. CONCLUSIONS: MSAP has no specific symptoms. The imaging appearance of MSAP is similar to mucinous cystic neoplasm of the pancreas. The tumor can gradually grow up and produce compression symptoms. MSAP can be cured by complete resection.