Looking to the future: biomarkers in the management of pancreatic adenocarcinoma

Relationship Between the Expression of O6-Methylguanine-DNA Methyltransferase (MGMT) and p53, and the Clinical Response in Metastatic Pancreatic Adenocarcinoma Treated with FOLFIRINOX

BACKGROUND

To date, no predictive biomarker for the efficacy of FOLFIRINOX in metastatic pancreatic adenocarcinoma has been demonstrated. Deficiency in O6-methylguanine-DNA methyltransferase (MGMT) has been associated with a therapeutic response in endocrine tumors of the pancreas and the lack of expression of protein 53 (p53) could interfere with the action of MGMT.

OBJECTIVE

The aim of our study was to assess the prevalence of MGMT and p53 in patients with metastatic pancreatic adenocarcinoma treated with FOLFIRINOX as a first-line treatment and to investigate their association with therapeutic response and survival.

PATIENTS AND METHODS

The immunohistochemical expression of MGMT was recorded as present or absent and the expression of p53 was semi-quantitatively scored in 30 patients with metastatic pancreatic adenocarcinoma, at Angers Hospital in France between September 2011 and June 2015. Clinical and radiologic data were collected retrospectively.

RESULTS

The presence or absence of MGMT expression entailed no significant differences in response rate. Median values of progression-free survival (PFS) and overall survival (OS) were lower in patients with MGMT expression, but sample size is too small to conclude that there is a statistically significant difference. No significant relationship for response rate and PFS was observed in relation with p53 expression. By contrast, patients with a strong tumor expression of p53 had a significantly lower OS compared to patients with no or weak expression of the protein (p = 0.027). There was a positive correlation between the expression of p53 and MGMT (p = 0.08).

CONCLUSIONS

These preliminary findings suggest that for patients treated with FOLFIRINOX as a first-line treatment for metastatic pancreatic adenocarcinoma, the immunohistochemical evaluation of MGMT could not predict the clinical outcome; however, the survival was not significant probably because of the under-powered study (due to small sample size). A strong tumor expression of p53 is associated with a poor prognosis of OS.

Phase I study of oxaliplatin in combination with gemcitabine, irinotecan, and 5-fluorouracil/leucovorin (G-FLIE) in patients with metastatic solid tumors including adenocarcinoma of the pancreas

PURPOSE

The aims of this study were to establish the maximum tolerated dose (MTD) of oxaliplatin in combination with fixed doses of gemcitabine, irinotecan, and 5-fluorouracil/leucovorin (G-FLIE) in solid tumors, including advanced pancreatic cancer, and to evaluate the toxicity of the regimen.

METHODS

Patients with metastatic solid tumors were treated with a regimen consisting of gemcitabine (500 mg/m(2) by fixed-dose-rate infusion), irinotecan (120 mg/m(2)), leucovorin 300 mg, bolus/infusion 5-fluorouracil (400 and 1,500 mg/m2, respectively), and oxaliplatin at doses from 50 to 85 mg/m(2) according to the escalation schema. Treatment was repeated every 14 days.

RESULTS

The study enrolled 25 patients with a median age of 64 years and median Karnofsky performance score of 80. Patients had metastatic adenocarcinomas of pancreas (n = 9), as well as gastroesointestinal, hepatobiliary, or unknown primary tumors. With only one dose limiting toxicity (neutropenia and constipation), the MTD of oxaliplatin was not reached up to the pre-specified maximum level of 85 mg/m(2). Other toxicities predictably included cytopenias, fatigue, sensory neuropathy, nausea/vomiting, diarrhea, and constipation. Four partial responses and ten disease stabilizations were observed. The overall median time to disease progression was 17 weeks (2-110 weeks) with median overall survival of 31.5 weeks (7-139 weeks).

CONCLUSIONS

G-FLIE is a tolerable multi-agent chemotherapy regimen with the oxaliplatin dose up to 85 mg/m(2). The combination of full-dose oxaliplatin with gemcitabine, irinotecan, and 5-fluorouracil is feasible with attenuated doses of the drugs, but further optimization is necessary before assessment of efficacy.

Laminin, gamma 2 (LAMC2): a promising new putative pancreatic cancer biomarker identified by proteomic analysis of pancreatic adenocarcinoma tissues

In pancreatic cancer, the incidence and mortality curves coincide. One major reason for this high mortality rate in pancreatic ductal adenocarcinoma (PDAC) patients is the dearth of effective diagnostic, prognostic, and disease-monitoring biomarkers. Unfortunately, existing tumor markers, as well as current imaging modalities, are not sufficiently sensitive and/or specific for early-stage diagnosis. There is, therefore, an urgent need for improved serum markers of the disease. Herein, we performed Orbitrap® mass spectrometry proteomic analysis of four PDAC tissues and their adjacent benign tissues and identified a total of 2190 nonredundant proteins. Sixteen promising candidates were selected for further scrutiny using a systematic scoring algorithm. Our preliminary serum verification of the top four candidates (DSP, LAMC2, GP73, and DSG2) in 20 patients diagnosed with pancreatic cancer and 20 with benign pancreatic cysts, showed a significant (p < 0.05) elevation of LAMC2 in pancreatic cancer serum. Extensive validation of LAMC2 in healthy, benign, and PDAC sera from geographically diverse cohorts (n = 425) (Japan, Europe, and USA) demonstrated a significant increase in levels in early-stage PDAC compared with benign diseases. The sensitivity of LAMC2 was comparable to CA19.9 in all data sets, with an AUC value greater than 0.85 in discriminating healthy patients from early-stage PDAC patients. LAMC2 exhibited diagnostic complementarity with CA19.9 by showing significant (p < 0.001 in two out of three cohorts) elevation in PDAC patients with clinically low CA19.9 levels.

Finding novel pharmaceuticals in the systems biology era using multiple effective drug targets, phenotypic screening and knowledge of transporters: where drug discovery went wrong and how to fix it

Despite the sequencing of the human genome, the rate of innovative and successful drug discovery in the pharmaceutical industry has continued to decrease. Leaving aside regulatory matters, the fundamental and interlinked intellectual issues proposed to be largely responsible for this are: (a) the move from 'function-first' to 'target-first' methods of screening and drug discovery; (b) the belief that successful drugs should and do interact solely with single, individual targets, despite natural evolution's selection for biochemical networks that are robust to individual parameter changes; (c) an over-reliance on the rule-of-5 to constrain biophysical and chemical properties of drug libraries; (d) the general abandoning of natural products that do not obey the rule-of-5; (e) an incorrect belief that drugs diffuse passively into (and presumably out of) cells across the bilayers portions of membranes, according to their lipophilicity; (f) a widespread failure to recognize the overwhelmingly important role of proteinaceous transporters, as well as their expression profiles, in determining drug distribution in and between different tissues and individual patients; and (g) the general failure to use engineering principles to model biology in parallel with performing 'wet' experiments, such that 'what if?' experiments can be performed in silico to assess the likely success of any strategy. These facts/ideas are illustrated with a reasonably extensive literature review. Success in turning round drug discovery consequently requires: (a) decent systems biology models of human biochemical networks; (b) the use of these (iteratively with experiments) to model how drugs need to interact with multiple targets to have substantive effects on the phenotype; (c) the adoption of polypharmacology and/or cocktails of drugs as a desirable goal in itself; (d) the incorporation of drug transporters into systems biology models, en route to full and multiscale systems biology models that incorporate drug absorption, distribution, metabolism and excretion; (e) a return to 'function-first' or phenotypic screening; and (f) novel methods for inferring modes of action by measuring the properties on system variables at all levels of the 'omes. Such a strategy offers the opportunity of achieving a state where we can hope to predict biological processes and the effect of pharmaceutical agents upon them. Consequently, this should both lower attrition rates and raise the rates of discovery of effective drugs substantially.

miR-143 inhibits the metastasis of pancreatic cancer and an associated signaling pathway

Pancreatic cancer is characterized by early metastasis and high mortality. In this study, the role of miR-143 in invasion and metastasis was investigated in pancreatic cancer cells. miR-143 expression was established by an adenovirus-carried miR-143 expression cassette. mRNA and protein levels of gene expression were examined by RT-PCR and Western blot assay, respectively. Rho GTPases activity was measured by the pull down assay. The role of miR-143 in migration and invasion of Panc-1 cells was tested in vitro. The antimetastatic effect of miR-143 was tested in a liver metastasis model, while its antitumor growth effect was tested in a xenograft Panc-1 tumor model. Results demonstrated that ARHGEF1 (GEF1), ARHGEF2 (GEF2), and K-RAS genes are the targets of miR-143. miR-143 expression significantly decreased mRNA and protein levels of GEF1, GEF2, and K-RAS genes; lowered the constitutive activities of RhoA, Rac1, and Cdc42 GTPases; decreased the protein levels of MMP-2 and MMP-9; but significantly increased the protein level of E-cadherin. miR-143 expression also significantly inhibited the migration and invasion of Panc-1 cells in vitro, liver metastasis, and xenograft tumor growth in vivo. Our study suggested that miR-143 plays a central role in the invasion and metastasis of pancreatic cancer and miR-143 is a potential target for pancreatic cancer therapy.

Identification of novel predictive markers for the prognosis of pancreatic ductal adenocarcinoma

Pancreatic cancer is a disease with poor prognosis and high mortality. To identify novel molecular markers that could predict the prognosis of pancreatic ductal adenocarcinoma, a total of 114 pancreatic ductal adenocarcinomas and 99 peritumoral tissues were collected. Protein levels of cleaved caspase-3, cyclin D1, epidermal growth factor receptor and Her-2 (human epidermal growth factor receptor 2) were measured by immunohistochemistry. Molecular abnormalities of cyclin D1/q11, Her-2/q17, and epidermal growth factor receptor/p7 were detected using fluorescence in situ hybridization. Results demonstrated that the protein levels of cleaved caspase-3, epidermal growth factor receptor, Her-2, and cyclin D1 were significantly higher in pancreatic ductal adenocarcinoma than that in peritumoral tissues (P = .000). Significantly more amplifications of epidermal growth factor receptor, Her-2, and cyclin D1 were observed in pancreatic ductal adenocarcinoma patients than in peritumoral tissues. In addition, 51.8% of pancreatic ductal adenocarcinoma tumors showed polysomy 7, 50% showed polysomy 11, and 40.4% showed polysomy 17. However, no polysomy was observed in peritumoral tissues. Her-2 amplification and polysomy 17 significantly correlated with poor prognosis of pancreatic ductal adenocarcinoma (P = .008 and P = .005, respectively). Interestingly, only cleaved caspase-3 protein level significantly correlated with poor survival in pancreatic ductal adenocarcinoma patients (P = .000). We also observed significant correlations of cleaved caspase-3 level with epidermal growth factor receptor, Her-2, and cyclin D1 protein levels and the molecular abnormalities of Her-2 and cyclin D1. Conclusively, cleaved caspase-3 level is an ideal biomarker to predict prognosis in pancreatic ductal adenocarcinoma patients and might be a better target for pancreatic ductal adenocarcinoma treatment than epidermal growth factor receptor/Her-2 and cyclin D1.

The predictive role of p16 deletion, p53 deletion, and polysomy 9 and 17 in pancreatic ductal adenocarcinoma

In this study, we investigated p53 and p16 deletions, and chromosome 9 and 17 amplifications in pancreatic ductal adenocarcinoma (PDAC), and further analyzed their associations with clinical characteristics and prognosis of PDAC. A total of 32 PDAC and 23 peritumoral tissues were collected. Molecular abnormalities of CEP9/p16 and CEP17/p53 were detected using Fluorescence in situ hybridization (FISH). Deletions of p16 and p53 were detected in 50 % and 65.7 % of PDAC, respectively. Polysomy 9 and 17 were identified in 75 % and 71.8 % of PDAC, respectively. No p16 and p53 deletion, polysomy 9 and 17 were identified in peritumoral tissues. We also observed significant correlations of p16 deletion, polysomy 9 and 17 with shorter survival of PDAC. P16 deletion, polysomy 9 and 17 are predictive markers for poor prognosis of PDAC patients, but p53 deletion is not associated with the clinical characteristics and prognosis of PDAC.

Everolimus enhances gemcitabine-induced cytotoxicity in bladder-cancer cell lines

The purpose of this study was to determine whether everolimus, a rapamycin derivative, might significantly enhance the cytotoxicity of gemcitabine, an antitumor drug, in two human bladder-cancer cell lines. Human bladder-cancer T24 and 5637 cells were incubated with gemcitabine and everolimus in a range of concentrations either alone or in combination for 72 h. Flow cytometry, comet assay, MTT method and optical microscopy were used to assess cell proliferation, cell cycle, DNA damage, and morphological alterations. Gemcitabine exerted an inhibitory effect on T24 and 5637 cell proliferation, in a concentration-dependent manner. Everolimus significantly reduced proliferation of 5637 bladder cancer cells (IC₃₀) at 1 μM), whereas T24 demonstrated marked resistance to everolimus treatment. A significant antiproliferative effect was obtained combining gemcitabine (100 nM) with everolimus (0.05-2 μM) with an arrest of cell cycle at S phase. Furthermore, an increase in frequency of DNA damage, apoptotic bodies, and apoptotic cells was observed when T24 and 5637 cancer cells were treated simultaneously with both drugs. Data show that in vitro combination produced a more potent antiproliferative effect when compared with single drugs.