Marco Del Chiaro

MicroRNA-21 in Pancreatic Cancer: Correlation with Clinical Outcome and Pharmacologic Aspects Underlying Its Role in the Modulation of Gemcitabine Activity

MicroRNA-21 (miR-21) was reported to be overexpressed and contributes to invasion and gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to evaluate whether miR-21 expression was associated with the overall survival (OS) of PDAC patients treated with gemcitabine and to provide mechanistic insights for new therapeutic targets. miR-21 expression was evaluated in cells (including 7 PDAC cell lines, 7 primary cultures, fibroblasts, and a normal pancreatic ductal cell line) and tissues (neoplastic specimens from 81 PDAC patients and normal ductal samples) isolated by laser microdissection. The role of miR-21 on the pharmacologic effects of gemcitabine was studied with a specific miR-21 precursor (pre-miR-21). Patients with high miR-21 expression had a significantly shorter OS both in the metastatic and in the adjuvant setting. Multivariate analysis confirmed the prognostic significance of miR-21. miR-21 expression in primary cultures correlated with expression in their respective tissues and with gemcitabine resistance. Pre-miR-21 transfection significantly decreased antiproliferative effects and apoptosis induction by gemcitabine, whereas matrix metalloproteinase (MMP)-2/MMP-9 and vascular endothelial growth factor expression were upregulated. Addition of inhibitors of phosphoinositide 3-kinase and mammalian target of rapamycin resulted in decrease of phospho-Akt and prevented pre-miR-21-induced resistance to the proapoptotic effects of gemcitabine. miR-21 expression correlated with outcome in PDAC patients treated with gemcitabine. Modulation of apoptosis, Akt phosphorylation, and expression of genes involved in invasive behavior may contribute to the role of miR-21 in gemcitabine chemoresistance and to the rational development of new targeted combinations.

Identification of MicroRNA-21 as a Biomarker for Chemoresistance and Clinical Outcome Following Adjuvant Therapy in Resectable Pancreatic Cancer

Background Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. The high risk of recurrence following surgical resection provides the rationale for adjuvant therapy. However, only a subset of patients benefit from adjuvant therapy. Identification of molecular markers to predict treatment outcome is therefore warranted. The aim of the present study was to evaluate whether expression of novel candidate biomarkers, including microRNAs, can predict clinical outcome in PDAC patients treated with adjuvant therapy. Methodology/Principal Findings Formalin-fixed paraffin embedded specimens from a cohort of 82 resected Korean PDAC cases were analyzed for protein expression by immunohistochemistry and for microRNA expression using quantitative Real-Time PCR. Cox proportional hazards model analysis in the subgroup of patients treated with adjuvant therapy (N = 52) showed that lower than median miR-21 expression was associated with a significantly lower hazard ratio (HR) for death (HR = 0.316; 95%CI = 0.166–0.600; P = 0.0004) and recurrence (HR = 0.521; 95%CI = 0.280–0.967; P = 0.04). MiR-21 expression status emerged as the single most predictive biomarker for treatment outcome among all 27 biological and 9 clinicopathological factors evaluated. No significant association was detected in patients not treated with adjuvant therapy. In an independent validation cohort of 45 frozen PDAC tissues from Italian cases, all treated with adjuvant therapy, lower than median miR-21 expression was confirmed to be correlated with longer overall as well as disease-free survival. Furthermore, transfection with anti-miR-21 enhanced the chemosensitivity of PDAC cells. Conclusions Significance Low miR-21 expression was associated with benefit from adjuvant treatment in two independent cohorts of PDAC cases, and anti-miR-21 increased anticancer drug activity in vitro. These data provide evidence that miR-21 may allow stratification for adjuvant therapy, and represents a new potential target for therapy in PDAC.

Risk factors for intraductal papillary mucinous neoplasm (ipmn) of the pancreas: A multicentre case-control study

OBJECTIVES:To investigate environmental, personal, and hereditary risk factors associated with the occurrence of intraductal papillary mucinous neoplasms of the pancreas (IPMNs).METHODS:Multicentre case–control study. Risk factors were identified from a questionnaire collecting data on family and medical history, and environmental factors. Cases were prevalent IPMNs seen at the participating units within an 18-month timeframe. Matched controls were enrolled alongside patients seen at outpatient clinics.RESULTS:Three-hundred and ninety patients with IPMN and 390 matched controls (166 males, mean age 65 in each group) were enrolled. Of the IPMNs, 310 had branch-duct involvement and 80 main-duct involvement. The only cancer with a 1st degree family history significantly higher in IPMN was pancreatic ductal adenocarcinoma (PDAC) (5.4% vs. 1.5%). Previous history of diabetes (13.6% vs. 7.5%), chronic pancreatitis (CP) (3.1% vs. 0.3%), peptic ulcer (7.2% vs. 4.3%), and insulin use (4.9% vs. 1.1%) were all more frequent with IPMNs. Logistic regression multivariate analysis revealed that history of diabetes (odds ratio (OR): 1.79, confidence interval (CI) 95%: 1.08–2.98), CP (OR: 10.10, CI 95%: 1.30–78.32), and family histories of PDAC (OR: 2.94, CI 95%: 1.17–7.39) were all independent risk factors. However, when analysis was restricted to diabetics who had taken insulin, risk of IPMN became stronger (OR: 6.03, CI 95%: 1.74–20.84). The association with all these risk factors seemed stronger for the subgroup with main duct involvement.CONCLUSIONS:A previous history of diabetes, especially with insulin use, CP, and family history of PDAC are all relevant risk factors for the development of IPMN. These results suggest an overlap between certain risk factors for PDAC and IPMN.

Cancer risk among the relatives of patients with pancreatic ductal adenocarcinoma.

Background/Aims: Pancreatic cancer is a leading cause of cancer-related death; the most consistently identified risk factors are smoking and family history. Our aims were to examine familial aggregations of pancreas and other cancers, and to determine the relative risk of the family members. Methods: We prospectively collected data on the families of patients presenting with pancreatic ductal adenocarcinoma. Smoking habits and alcohol consumption of the probands were compared with the available statistics on the Italian population. Mortality from cancer was investigated in first-degree relatives, and age-dependent risks of dying from pancreatic cancer and other tumors were compared with background population levels. Results: Data for 570 families were collected, including 9,204 relatives. Probands were 3- to 5-fold more often heavy smokers than the general population, and 9.3% of them reported a positive family history of pancreatic cancer. In first-degree relatives, only mortality from pancreatic cancer was significantly increased (relative risk at age 85 years = 2.7). Lifetime risk of dying of pancreas cancer was 4.1% for the relatives of all probands, and was 7.2% for the relatives of probands who developed disease before 60 years of age. Conclusions: The data suggest that genetic susceptibility to pancreatic cancer may be attributable, in addition to BRCA2, to moderate- to low-penetrance gene(s).

Familial pancreatic cancer in Italy. Risk assessment, screening programs and clinical approach: a position paper from the Italian Registry.

In Italy, pancreatic cancer is the fifth leading cause of tumor related death with about 7000 new cases per year and a mortality rate of 95%. In a recent prospective epidemiological study on the Italian population, a family history was found in about 10% of patients suffering from a ductal adenocarcinoma of the pancreas (PDAC). A position paper from the Italian Registry for Familial Pancreatic Cancer was made to manage these high-risk individuals. Even though in the majority of high-risk individuals a genetic test to identify familial predisposition is not available, a screening protocol seems to be reasonable for subjects who have a >10-fold greater risk for the development of PDAC. However this kind of screening should be included in clinical trials, performed in centers with high expertise in pancreatic disease, using the least aggressive diagnostic modalities.

Laser microdissection and primary cell cultures improve pharmacogenetic analysis in pancreatic adenocarcinoma.

A key focus of research on pancreatic ductal adenocarcinoma (PDAC) is identifying new techniques to tailor gemcitabine and 5-fluorouracil treatments. Availability of tumor tissue is critical for the accurate assessment of gene expression, and laser microdissection (LMD) and primary cell cultures may be useful tools to separate tumor cells from the stromal reaction. The aim of this study was (1) to address the genetic profile relevant to drug activity and (2) to evaluate differences between microdissected and non-microdissected tumors, normal tissues, and primary cell cultures. Quantitative PCR of seven key genes was performed on mRNA from 113 microdissected and 28 non-microdissected tumors, a pool of normal tissues and four established primary cell lines. Protein expression was evaluated by western blot and immunocytochemistry and cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. LMD allowed the analysis of 110 samples and revealed significant differences in mRNA levels between microdissected tumors and normal tissues, as well as between non-microdissected and microdissected tumors from the same patients. In contrast, primary cell lines showed similar expression profiles with respect to their respective microdissected tumors. In particular, expression levels of human equilibrative nucleoside transporter-1 and thymydilate synthase were significantly related to gemcitabine and 5-fluorouracil cytotoxicity. We conclude that LMD is a reliable technique for mRNA extraction, and allows detection of significant differences in the expression of specific target genes when compared to non-microdissected specimens and normal tissues. Moreover, expression levels in microdissected tumors are similar to those observed in primary tumor cell cultures, both at mRNA and protein level, and are related to drug chemosensitivity. The use of these ex vivo techniques for molecular analysis of tumors therefore appears to be of some value in implementing the clinical management of PDAC.

Improved insulin secretory function and reduced chemotactic properties after tissue culture of islets from type 1 diabetic patients

Type 1 diabetes results from the destruction of pancreatic beta‐cell as a consequence of an autoimmune process. To date, information on the properties of islets isolated from type 1 diabetic patients is very scant.

A Benefit-Risk Assessment of Basiliximab in Renal Transplantation

Interleukin-2 (IL-2) and its receptor (IL-2R) play a central role in T lymphocyte activation and immune response after transplantation. Research on the biology of IL-2R allowed the identification of key signal transduction pathways involved in the generation of proliferative and antiapoptotic signals in T cells. The α-chain of the IL-2R is a specific peptide against which monoclonal antibodies have been raised, with the aim of blunting the immune response by means of inhibiting proliferation and inducing apoptosis in primed lymphocytes. Indeed, basiliximab, one of such antibodies, has proved to be effective in reducing the episodes of acute rejection after kidney and pancreas transplantation.The use of basiliximab was associated with a significant reduction in the incidence of any treated rejection episodes after kidney transplantation in the two major randomised studies (placebo 52.2% vs basiliximab 34.2% at 6 months, European study; placebo 54.9% vs basiliximab 37.6% at 1 year, US trial). Basiliximab and equine antithymocyte globulin (ATG) administration resulted in a similar rate of biopsy-proven acute rejection at 6 months (19% for both) and at 12 months (19% and 20%, respectively). The use of basiliximab appears not to be associated with an increased incidence of adverse events as compared with placebo in immunosuppressive regimens, including calcineurin inhibitors, mycophenolate mofetil or azathioprine and corticosteroids, and its safety profile is superior to ATG. Moreover, a similar occurrence of infections is noted in selected studies (65.5% after basiliximab vs 65.7% of controls), including cytomegalovirus infection (17.3% vs 14.5%), and cytokine-release syndrome is not observed. Finally, economic analysis demonstrated lower costs of overall treatment in patients treated with basiliximab.Therefore, the use of basiliximab entails a very low risk, allows safe reduction of corticosteroid dosage and reduces the short- and mid-term rejection rates. However, the improvement in the long-term survival of kidney grafts in patients treated according to modern immunosuppressive protocols is still to be demonstrated. These conclusions are based on a systematic review of the scientific literature, indexed on Medline database, concerning the mechanism of action, therapeutic activity, safety and pharmacoeconomic evaluation of basiliximab in renal transplantation.

Effects of C-peptide on isolated human pancreatic islet cells

Recent data have demonstrated that pro‐insulin‐derived C‐peptide can affect the function of several different cell types. We hypothesized that C‐peptide might have an influence on the function and survival of isolated human islets.

Loss of Heterozygosity Status of D9S105 Marker Is Associated with Downregulation of Krüppel-Like Factor 4 Expression in Pancreatic Ductal Adenocarcinoma and Pancreatic Intraepithelial Lesions

The transcription factor Krüppel-like factor 4 (KLF4) may act both as an oncogene and a tumor suppressor in a tissue-dependent manner, and further studies on its role in pancreatic ductal adenocarcinoma (PDAC) progression and clinical outcome are warranted. Therefore, we investigated the loss of heterozygosity (LOH) in the 9q22.3–32 region and loss of KFL4 gene expression in epithelial cells from 35 PDAC, 6 pancreatic intraductal neoplasias (PanINs) and 6 normal ducts, isolated by laser microdissection, as well as their correlation with overall survival (OS) in patients treated with gemcitabine in the adjuvant setting. LOH was evaluated with 4 microsatellite markers and in situ hybridization, while KLF4 expression was studied by reverse transcription-PCR and immunohistochemistry. LOH in at least 1 locus was observed in 25 of 35 PDAC cases and in 5 of 6 PanINs, respectively. In particular, the loss of the D9S105 marker was present in 46.9% of PDAC and 83.3% of PanINs, becoming the most deleted marker, while no LOH in D9S105 was observed in normal Wirsung pancreatic duct. Lack of KLF4 mRNA expression was significantly associated with: (1) genomic deletion flanking KLF4 in PDAC and in PanINs (with LOH of D9S105), (2) low-grade PDAC-associated PanIN, (3) lack of KLF4 protein expression, and (4) shorter OS. These results strongly suggest a relationship between D9S105 deletion and downregulation of KLF4 gene expression as an early event in PDAC progression, as well as a possible role of KLF4 as a prognostic biomarker in gemcitabine-treated patients.