Adjuvant/Perioperative Therapy in Pancreatic and Periampullary Cancer

The delivery of postoperative combined modality adjuvant therapy for completely resected pancreatic adenocarcinoma was initially shown to be beneficial based on a prospective, randomized trial published 30 years ago. Since then, oncologists have debated whether chemotherapy alone, chemoradiation, or both are optimal adjuvant therapies following pancreatectomy for pancreatic ductal adenocarcinomas (PDAC). No global consensus has emerged, and there is no one superior modality despite randomized trials in part, to poor trial design, poor patient selection, and poor therapy options itself. We need to have a disciplined approach to the selection of patients for pancreatectomy, pathologic assessment of surgical resection margins, and postoperative (pre-treatment) imaging. In the era of the multidetector CT optimized for pancreatic imaging, tumors of “borderline resectability” have emerged as a distinct subset of PDAC. The attempt to standardize the definition of borderline resectable is a work in progress and modified with time. This distinction (between resectable and borderline resectable) is essential to minimize potentially confounding results of clinical trials. Additionally, preoperative therapy is not only preferred but mandatory in a large population of borderline resectable patients. Ultimately, as we develop more effective systemic therapies for PDAC, proceeding with surgery after a period of induction therapy will be even more compelling especially if there is a clear positive impact on overall survival.     

Taxotere resistance in SUIT Taxotere resistance in pancreatic carcinoma cell line SUIT 2 and its sublines

AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC). METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and its sublines (S-007, S-013, S-020, S-028 and TXT selected SUIT-2 cell line, S2/TXT) to TXT. Mdr1 (P-gp), multidrug resistance associated protein (MRP), lung resistance protein (LRP) and beta-tubulin isotype gene expressions were detected by RT-PCR. The functionality of P-gp and MRP was tested using their specific blocker verapamil (Ver) and indomethacin (IMC), respectively. The transporter activity of P-gp was also confirmed by Rhodamine 123 accumulation assay. RESULTS: S-020 and S2/TXT were found to be significantly resistant to TXT(19 and 9.5-fold to their parental cell line SUIT-2, respectively). RT-PCR demonstrated strong expression of Mdr1 in these two cell lines, but weaker expression or no expression in other cells lines. MRP and LRP expressions were found in most of these cell lines. The TXT-resistance in S2-020 and S2/TXT could be reversed almost completely by Ver, but not by IMC. Flow cytometry showed that Ver increased the accumulation of Rhodamine-123 in these two cell lines. Compared with S-020 and SUIT-2, the levels of beta-tubulin isotype II, III expressions in S-2/TXT were increased remarkably. CONCLUSION: The both intrinsic and acquired TXT-related drug resistance in these PAC cell lines is mainly mediated by P-gp, but had no relationship to MRP and LRP expressions. The increases of beta-tubulin isotype II, III might be collateral changes that occur when the SUIT-2 cells are treated with TXT.     

The effect of biguanides on secretion and biosynthesis of insulin in isolated pancreatic islets of rats

Summary Based on the clinical observation that biguanide treatment of obese patients may alter insulin levels, the influence of metformin and phenformin on basal and glucose stimulated insulin secretion, as well as on insulin biosynthesis, was studied in isolated islets of rats. — Biguanide concentrations of 100 g/ml, or higher, significantly reduced glucose stimulated insulin secretion. Both dose dependence and a difference in the intrinsic activities of metformin and phenformin were demonstrated. Incubating the same islets for a second period without biguanides, glucose stimulated insulin secretion was still decreased. Addition of glibenclamide during this second period increased insulin secretion, but did not overcome complete inhibition achieved after incubation at very high biguanide concentrations. Glucose stimulated biosynthesis of proinsulin and insulin was decreased in the presence of biguanides and completely suppressed at very high concentrations. Inhibition of cell respiration in the islet cells effected by high biguanide doses may be the reason for the inhibition of secretion and biosynthesis of insulin. — On the other hand, an insulin release was found at the highest phenformin concentration of 10 mg/ ml and during perfusion of the isolated rat pancreas with higher biguanide doses. — Biguanide concentrations found to be effective in this study are very high compared with therapeutic levels. Moreover, biguanide actions are known to be highly dependent on species, concentration and metabolic situation. — Definite conclusions from these findings regarding clinical significance, therefore, seem unwarranted.Supported by Deutsche Forschungsgemeinschaft, Bonn-Bad Godesberg.     

Downregulation of GSTM2 enhances gemcitabine chemosensitivity of pancreatic cancer in vitro and in vivo

Glutathione-S-transferases (GSTs) not only show cytoprotective role and their involvement in the development of anticancer drug resistance, but also transmit signals that control cell proliferation and apoptosis. However, the role of GST isoforms in chemotherapy resistance remains elusive in pancreatic cancer. Here, we demonstrated that gemcitabine treatment increased the GSTM2 expression in pancreatic cancer cell lines. Knockdown of GSTM2 by siRNA elevated apoptosis and decreased viability of pancreatic cancer cells treated with gemcitabine. Moreover, in vivo experiments further showed that shRNA induced GSTM2 downregulation enhanced drug sensitivity of gemcitabine in orthotopic pancreatic tumor mice. We also found that GSTM2 levels were lower in tumor tissues than in non-tumor tissues and higher GSTM2 expression was significantly associated with longer overall survival. In conclusion, our findings indicate that GSTM2 expression is essential for the survival of pancreatic cancer cells undergoing gemcitabine treatment and leads to chemo resistance. Downregulation of GSTM2 in pancreatic cancer may benefit gemcitabine treatment. GSTM2 expression in patients also shows significant correlation with overall survival. Thus, our study suggests that GSTM2 is a potential target for chemotherapy optimization and prognostic biomarker of pancreatic cancer.     

Origin of the long common channel based on pancreatographic findings in pancreaticobiliary maljunction

BACKGROUND AND AIMS: The origin of a long common channel in pancreaticobiliary maljunction was suggested to be the ventral pancreatic duct. Pathogenesis of long common channels was investigated by anatomically analysing the arrangement of pancreatic ducts in pancreaticobiliary maljunction. MATERIALS AND METHODS: Cholangiopancreatography was performed for 66 cases of pancreaticobiliary maljunction and 200 controls. The accessory pancreatic duct was classified according to course and shape. In cases with long- or short-type accessory pancreatic duct, lengths of the main pancreatic duct from orifice to first inferior branch and junction with the accessory pancreatic duct, and the common channel were measured. RESULTS: Lengths of the main pancreatic duct from orifice to first inferior branch or junction with the accessory pancreatic duct were significantly longer in cases of pancreaticobiliary maljunction cases with the long- or short-type accessory pancreatic duct than in controls (p<0.01). Lengths of the main pancreatic duct from first inferior branch to junction with the accessory pancreatic duct were roughly equivalent in pancreaticobiliary maljunction and controls. CONCLUSIONS: Long common channels in pancreaticobiliary maljunction might be formed embryologically with adhesion of the right ventral pancreatic duct and the terminal portion of the bile duct.     

Persistent reduction of pancreatic Beta-cell mass after a limited period of protein-energy malnutrition in the young rat

Summary Kwashiorkor, the human disease of protein-energy malnutrition, has been implicated in the aetiology of malnutrition-related diabetes mellitus, a form of diabetes not uncommon in developing countries. We have previously demonstrated that temporary protein-energy malnutrition in young rats causes a persisting impairment of insulin secretion. The present study investigates whether this secretory deficiency is accompanied by structural alterations of the endocrine pancreas. Three-week-old rats were weaned onto semi-synthetic diets containing either 15% or 5% protein and these diets were maintained for 3 weeks. From 6 weeks of age all rats were fed a commercial chow containing 18% protein. The endocrine pancreas was investigated by light and electron microscopic morphometry at 3, 6 and 12 weeks of age. In rats not subjected to protein-energy malnutrition there was a progressive increase, with age, of total pancreatic Beta-cell weight and individual Beta-cell size. In 6-week-old rats fed the low protein diet total pancreatic Beta-cell weight and individual Beta-cell size were diminished. In 12-week-old rats previously fed the low protein diet total Beta-cell weight remained lower compared to control rats. It is concluded that protein-energy malnutrition early in life may result in a diminished reserve for insulin production. This may predispose to glucose intolerance or even diabetes in situations with an increased insulin demand.This work was presented in part at the 26th Annual Meeting of the European Association for the Study of Diabetes in Copenhagen, Denmark 10–13 September 1990     

Dietary oleic acid is inversely associated with pancreatic cancer – Data from food diaries in a cohort study

Background

Dietary oleic acid may prevent pancreatic ductal adenocarcinoma (PDA) by reducing hyperinsulinaemia which can otherwise promote DNA damage and tumour growth. Results from previous epidemiological studies investigating oleic acid are inconsistent. This study aims to clarify the relationship between dietary oleic acid intake and the risk of developing PDA using nutritional information from food diaries plus published serum biomarker data from HbA1c.

Staging laparoscopy leads to rapid induction of chemotherapy for unresectable pancreatobiliary cancers

Preoperatively evaluating the resectability of pancreatobiliary cancers is difficult. The aim of this study was to investigate the benefit of staging laparoscopy in unresectable pancreatobiliary cancers. Between 2010 and 2013, 25 patients with pancreatobiliary cancers underwent staging laparoscopy after conventional tumor staging; they were compared with 10 patients who had unresectable or metastatic tumors that were found during laparotomy. Staging laparoscopy did not show unresectable factors in 11 patients, and resections were performed in these patients. Unresectable factors were found in other 14 patients who underwent staging laparoscopy. In these patients, chemotherapy was started after median postoperative day 3 (range, 2–10 days). This period was significantly longer in patients who received unnecessary laparotomy; chemotherapy was started after median postoperative day 11 (range, 6–15 days). These results suggest that staging laparoscopy, while avoiding laparotomy with unsuccessful resection, can lead to rapid induction of chemotherapy for unresectable pancreatobiliary cancers.     

S100A12在重症急性胰腺炎治疗中的潜在作用

目的探讨钙结合蛋白S100A12在小鼠重症急性胰腺炎治疗中的潜在作用。方法采用连续7次腹腔注射雨蛙素50μg/kg(每次间隔1 h)及脂多糖建立小鼠急性胰腺炎模型。将160只SPF级雌性ICR小鼠随机分为对照组(A组,生理盐水)、轻型组(B组,雨蛙素)、重症组(C组,雨蛙素+脂多糖)、干预组(D组,S100A12重组抗体+雨蛙素+脂多糖),每组40只。在首次注射雨蛙素后8 h、12 h和24 h采血,分别检测各时段血清中S100A12、淀粉酶(AMY)、C反应蛋白(CRP)、白介素(IL-1β、IL-6)、肿瘤坏死因子(TNF-α)的含量,观察小鼠胰腺的病理形态并进行评分。结果与C组相比,D组各时段血清中AMY、CRP、IL-1β、IL-6、TNF-α、S100A12含量明显降低(P0.05);与B组相比,D组各时段血清S100A12浓度明显降低(P0.05),胰腺病理形态也有明显改善。结论 S100A12重组抗体能够有效降低小鼠急性胰腺炎的严重程度,S100A12可以作为重症急性胰腺炎治疗的一个有效靶点。