Focal adhesion kinase inhibition synergizes with nab-paclitaxel to target pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a very lethal disease, with minimal therapeutic options. Aberrant tyrosine kinase activity influences tumor growth and is regulated by phosphorylation. We investigated phosphorylated kinases as target in PDAC. METHODS: Mass spectrometry-based phosphotyrosine proteomic analysis on PDAC cell lines was used to evaluate active kinases. Pathway analysis and inferred kinase activity analysis was performed to identify novel targets. Subsequently, we investigated targeting of focal adhesion kinase (FAK) in vitro with drug perturbations in combination with chemotherapeutics used against PDAC. Tyrosine phosphoproteomics upon treatment was performed to evaluate signaling. An orthotopic model of PDAC was used to evaluate the combination of defactinib with nab-paclitaxel. RESULTS: PDAC cell lines portrayed high activity of multiple receptor tyrosine kinases to various degree. The non-receptor kinase, FAK, was identified in all cell lines by our phosphotyrosine proteomic screen and pathway analysis. Targeting of this kinase with defactinib validated reduced phosphorylation profiles. Additionally, FAK inhibition had anti-proliferative and anti-migratory effects. Combination with (nab-)paclitaxel had a synergistic effect on cell proliferation in vitro and reduced tumor growth in vivo. CONCLUSIONS: Our study shows high phosphorylation of several oncogenic receptor tyrosine kinases in PDAC cells and validated FAK inhibition as potential synergistic target with Nab-paclitaxel against this devastating disease.

Co-expression analysis of pancreatic cancer proteome reveals biology and prognostic biomarkers.

PURPOSE: Despite extensive biological and clinical studies, including comprehensive genomic and transcriptomic profiling efforts, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease, with a poor survival and limited therapeutic options. The goal of this study was to assess co-expressed PDAC proteins and their associations with biological pathways and clinical parameters. METHODS: Correlation network analysis is emerging as a powerful approach to infer tumor biology from omics data and to prioritize candidate genes as biomarkers or drug targets. In this study, we applied a weighted gene co-expression network analysis (WGCNA) to the proteome of 20 surgically resected PDAC specimens (PXD015744) and confirmed its clinical value in 82 independent primary cases. RESULTS: Using WGCNA, we obtained twelve co-expressed clusters with a distinct biology. Notably, we found that one module enriched for metabolic processes and epithelial-mesenchymal-transition (EMT) was significantly associated with overall survival (p = 0.01) and disease-free survival (p = 0.03). The prognostic value of three proteins (SPTBN1, KHSRP and PYGL) belonging to this module was confirmed using immunohistochemistry in a cohort of 82 independent resected patients. Risk score evaluation of the prognostic signature confirmed its association with overall survival in multivariate analyses. Finally, immunofluorescence analysis confirmed co-expression of SPTBN1 and KHSRP in Hs766t PDAC cells. CONCLUSIONS: Our WGCNA analysis revealed a PDAC module enriched for metabolic and EMT-associated processes. In addition, we found that three of the proteins involved were associated with PDAC survival.

Role of proton-coupled folate transporter in pemetrexed resistance of mesothelioma: clinical evidence and new pharmacological tools.

BACKGROUND: Thymidylate synthase (TS) has a predictive role in pemetrexed treatment of mesothelioma; however, additional chemoresistance mechanisms are poorly understood. Here, we explored the role of the reduced-folate carrier (RFC/SLC19A1) and proton-coupled folate transporter (PCFT/SLC46A1) in antifolate resistance in mesothelioma. PATIENTS AND METHODS: PCFT, RFC and TS RNA and PCFT protein levels were determined by quantitative RT-PCR of frozen tissues and immunohistochemistry of tissue-microarrays, respectively, in two cohorts of pemetrexed-treated patients. Data were analyzed by t-test, Fisher's/log-rank test and Cox proportional models. The contribution of PCFT expression and PCFT-promoter methylation to pemetrexed activity were evaluated in mesothelioma cells and spheroids, through 5-aza-2'-deoxycytidine-mediated demethylation and siRNA-knockdown. RESULTS: Pemetrexed-treated patients with low PCFT had significantly lower rates of disease control, and shorter overall survival (OS), in both the test (N = 73, 11.3 versus 20.1 months, P = 0.01) and validation (N = 51, 12.6 versus 30.3 months, P = 0.02) cohorts. Multivariate analysis confirmed PCFT-independent prognostic role. Low-PCFT protein levels were also associated with shorter OS. Patients with both low-PCFT and high-TS levels had the worst prognosis (OS, 5.5 months), whereas associations were neither found for RFC nor in pemetrexed-untreated patients. PCFT silencing reduced pemetrexed sensitivity, whereas 5-aza-2'-deoxycytidine overcame resistance. CONCLUSIONS: These findings identify for the first time PCFT as a novel mesothelioma prognostic biomarker, prompting prospective trials for its validation. Moreover, preclinical data suggest that targeting PCFT-promoter methylation might eradicate pemetrexed-resistant cells characterized by low-PCFT expression.

Prognostic factors for pancreatic neuroendocrine neoplasms (pNET) and the risk of small non-functioning pNET.

BACKGROUND: Non-functioning (NF) pancreatic neuroendocrine tumors (pNET) often have an indolent outcome. A consensus to submit patients with large (>2 cm) NF-pNET to surgery already exists; but a conservative approach for small (≤2 cm) NF neoplasms has been proposed. AIM: To identify prognostic factors for survival and progression free survival (PFS) of NF-pNET, evaluating whether surgery may be avoided for small NF-pNET. SUBJECTS AND METHODS: Retrospective study of 77 consecutive patients with pNET submitted to surgery, of which 60 were NF. Pathological tissues were revised according to the 2000 and 2010 WHO classifications. Risk factors for survival and PFS were evaluated using the Kaplan-Meier method and the Cox regression model. RESULTS: The 8-year cause-specific survival of NF-pNET was 79.3%. At univariate analysis, high grading, high staging, large tumors, angioinvasion and peri-pancreatic infiltration were significantly associated with a shorter survival; at multivariate analysis only peri-pancreatic infiltration was significantly associated with a shorter NF-pNET survival. Most small NF-pNET were grade 1 (74%), compared to large NF-pNET (27%). Distant metastases were present in 29.7% (n = 11) and 17.4% (n = 4) of patients with large or small NF-pNET, respectively; among the 19 small NF-pNET without metastasis, five had a local malignancy (lymph node metastasis or local infiltration); thus, 39% of the 23 NF-pNET, turned out to have a malignant potential. CONCLUSIONS: Among NF-pNET, large neoplasms were associated with worse outcomes; however, small NF-pNET do not seem to have an invariable benign behavior. Whether surgery should be avoided in all patients with small NF-pNET is questionable.

Does thyroid peroxidase provide an antigenic link between thyroid autoimmunity and breast cancer?

Women with breast cancer (BC) and antithyroid peroxidase (TPO) autoantibodies (TPOAb) have a better prognosis than women lacking TPOAb. Sera from women with TPOAb displayed immunoreactivity to BC tissue by immunofluorescence that was not apparent in women without TPOAb. We hypothesize a BC/thyroid shared antigen that provides a target for humoral or cell-mediated immune activity; candidates include the sodium/iodide symporter (expressed in thyroid and BC), cross-reacting epitopes in TPO and lactoperoxidase (LPO) or TPO itself. As the association is with TPOAb, we investigated TPO expression in BC, breast peritumoral tissue (PT), other tissues (tumoral and not) and thyroid as positive control. Transcripts for known and novel TPO isoforms were detected in BC (n = 8) and PT (n = 8) but at approximately 10(4) -fold lower than in thyroid while in non-BC tumors (n = 5) they were at the limit of detection. TPO was expressed also in adipose tissue (n = 17), 10(3) -fold lower than in thyroid. Full length TPO (Mr 105-110 kDa) was detected in Western blots in the majority of examined tissues; preabsorption of the TPO antibody with recombinant TPO (but not LPO) reduced the signal, indicating specificity. The same occurred with some lower molecular weight bands, which could correspond to smaller TPO transcript isoforms, present in all samples. In conclusion, TPO is weakly expressed in BC and other tissues; this could partly explain the high frequency and protective role of TPOAb in BC patients. Further studies will investigate tissue specificity, function and immunogenicity of the novel TPO variants (some BC-specific) identified.

MET as a potential target for the treatment of upper gastrointestinal cancers: characterization of novel c-Met inhibitors from bench to bedside.

The receptor tyrosine kinase mesenchymal-epithelial transition factor (c-Met) plays a pivotal role in regulation of cell proliferation and migration. Abnormal expression of c-Met has been associated with poor prognosis in several cancer types, including upper gastrointestinal malignancies. Moreover, c-Met interaction with multiple signalling pathways involved in tumor growth and invasive/metastatic phenotype has gained substantial attention in the last few years, suggesting the therapeutic potential of this target. This has led to the development and evaluation of a number of c-Met inhibitors. Here we describe the critical role of the HGF/c-Met pathway in cancer, as well as the preclinical and clinical investigations on c-Met inhibitors in solid tumors, with particular emphasis on recent findings with small-molecule inhibitors in gastrointestinal cancers. Clinical trials with several of these novel inhibitors have been encouraging and one of them, crizotinib (dual c-Met/ALK inhibitor), has recently been approved for lung cancers with ALK-rearrangement. There are accumulating evidences on the therapeutic potential of this and other c-Met inhibitors for the treatment of other malignancies, such as gastric and pancreatic cancers. These inhibitors might be used in combination with chemotherapy as well as with other biological agents, in order to overcome different resistance mechanisms. However, further studies are needed to identify determinants of the activity of c-Met inhibitors, through the analysis of genetic and environmental alterations affecting c-Met and parallel pro-cancer pathways. These studies will be critical to improve the efficacy and selectivity of current and future anticancer strategies targeting c-Met.

Synergistic interaction of novel lactate dehydrogenase inhibitors with gemcitabine against pancreatic cancer cells in hypoxia.

BACKGROUND: Hypoxia is a driving force in pancreatic-ductal-adenocarcinoma (PDAC) growth, metastasis and chemoresistance. The muscle-isoform of lactate dehydrogenase (LDH-A) constitutes a major checkpoint for the switch to anaerobic glycolysis, ensuring supply of energy and anabolites in hypoxic-environments. Therefore, we investigated the molecular mechanisms underlying the pharmacological interaction of novel LDH-A inhibitors in combination with gemcitabine in PDAC cells. METHODS: Lactate dehydrogenase A levels were studied by quantitative RT-PCR, western blot, immunofluorescence and activity assays in 14 PDAC cells, including primary-cell-cultures and spheroids, in normoxic and hypoxic conditions. Cell proliferation, migration and key determinants of drug activity were evaluated by sulforhodamine-B-assay, wound-healing assay, PCR and LC-MS/MS. RESULTS: Lactate dehydrogenase A was significantly increased under hypoxic conditions (1% O2), where the novel LDH-A inhibitors proved to be particularly effective (e.g., with IC50 values of 0.9 vs 16.3 µM for NHI-1 in LPC006 in hypoxia vs normoxia, respectively). These compounds induced apoptosis, affected invasiveness and spheroid-growth, reducing expression of metalloproteinases and cancer-stem-like-cells markers (CD133+). Their synergistic interaction with gemcitabine, with combination index values <0.4 in hypoxia, might also be attributed to modulation of gemcitabine metabolism, overcoming the reduced synthesis of phosphorylated metabolites. CONCLUSION: Lactate dehydrogenase A is a viable target in PDAC, and novel LDH-A inhibitors display synergistic cytotoxic activity with gemcitabine, offering an innovative tool in hypoxic tumours.

Histopathologic evaluation of liver metastases from colorectal cancer in patients treated with FOLFOXIRI plus bevacizumab.

BACKGROUND: The FOLFOXIRI regimen produces a high rate of radiological and histopathological responses. Bevacizumab added to chemotherapy showed an improvement in pathological response and necrosis of colorectal liver metastases (CLMs). FOLFOXIRI plus bevacizumab produced promising early clinical results and is under investigation in several randomised trials, although no data are currently available on its effects on response of CLMs and on liver toxicities. METHODS: Starting from 499 patients enrolled in first-line phase II/III trials, we selected on the basis of tissue sample availability 18 patients treated with FOLFOXIRI/XELOXIRI and 24 patients treated with FOLFOXIRI plus bevacizumab who underwent secondary resection of CLMs. The 28 untreated patients who underwent primary resection of CLMs were included as control group. Responses of CLMs and chemotherapy-induced toxicities were assessed. RESULTS: Among the patients, 63% of those treated with FOLFOXIRI plus bevacizumab, as compared with 28% of those treated with only FOLFOXIRI/XELOXIRI, showed a histopathological response (P=0.033). In the two groups, 52% and 12.5%, respectively, showed necrosis ≥50% (P=0.017). The incidence of liver toxicities was not significantly increased in patients treated with FOLFOXIRI plus bevacizumab. CONCLUSION: The addition of bevacizumab to FOLFOXIRI produces high rates of pathologic responses and necrosis of CLM without increasing liver toxicity.

Adjuvant chemotherapy seems beneficial for invasive intraductal papillary mucinous neoplasms.

AIMS: The incidence of intraductal papillary mucinous neoplasm (IPMN) is rising and these neoplasms now represent up to 25% of resected pancreatic neoplasms. The optimal postoperative management of resected invasive IPMN is still debated in the absence of large prospective clinical trials and of validated prognostic factors in this setting. The objective of our study was to identify potential prognostic factors and to investigate the role of adjuvant therapies for patients radically resected for invasive IPMN. METHODS: We retrospectively reviewed clinical and pathological data regarding a large series of patients with invasive IPMN who underwent surgical resection in the last six years at University Hospital of Pisa. RESULTS: Sixty-four patients were considered for the analysis, thirty-three of whom received adjuvant chemotherapy with gemcitabine. In our series node involvement and high tumoral grade emerged as the major pathologic prognostic factors. Patients treated with adjuvant chemotherapy with gemcitabine experienced a longer disease-free survival than those who received surgery alone. CONCLUSIONS: Gemcitabine-based chemotherapy seems beneficial as adjuvant treatment for patients with resected invasive IPMN.

Ectopic expression of FSH receptor isoforms in neoplastic but not in endothelial cells from pancreatic neuroendocrine tumors.

FSH receptor (FSHR) expression is restricted to gonads, where it drives FSH-dependent cell differentiation; in addition, FSHR plays an important role in the regulation of ovarian angiogenesis. Recently, FHSR expression has been shown in blood vessels of various tumors. However, pancreatic neuroendocrine tumors (p-NET), which have high-degree blood supply, were not included in that study. The aim of this study was to evaluate FSHR expression in p-NET. FSHR expression was evaluated in tumor samples from 30 patients with p-NET by immunohistochemistry and Western blot; fluorescence microscopy was used to localize FSHR in specific cells from tissue samples. von Willebrand factor (vWF) and chromograninA (chrA) was used as blood vessel and NET cells marker, respectively, to co-localize FSHR. FSHR expression was detected in all p-NET by immunohistochemistry. Western blot confirmed FSHR expression on p- NET although different FSHR isoforms, ranging from 240 kD to 55 kD were found in the samples studied. Surprisingly, FSHR co-localized with chrA but not with vWF, suggesting that neoplastic cells of neuroendocrine origin rather than blood vessels expressed FSHR. No relationship was found between degree of FSHR expression and histology of p-NET. FSHR may be aberrantly expressed in neoplastic cells from p-NET and not in tumor blood vessels; however, its biological significance as well as its clinical relevance remains to be elucidated.

The good, the bad and the ugly: a tale of miR-101, miR-21 and miR-155 in pancreatic intraductal papillary mucinous neoplasms.

BACKGROUND: This multicenter study evaluated three candidate microRNAs (miRNAs) (miR-21, miR-155 and miR-101) as potential biomarkers in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. PATIENTS AND METHODS: miRNA expression was quantified by quantitative RT-PCR in 86 laser-microdissected specimens, including 65 invasive IPMNs, 16 non-invasive IPMNs and 5 normal pancreatic ductal tissues. Univariate and multivariate analyses compared miRNAs and clinical parameters with overall (OS) and disease-free survival (DFS). RESULTS: miR-21 and miR-155 were up-regulated in invasive IPMNs compared with non-invasive IPMNs, as well as in non-invasive IPMNs compared with normal tissues. Conversely, miR-101 levels were significantly higher in non-invasive IPMNs and normal tissues compared with invasive IPMNs. High levels of miR-21 were associated with worse OS [hazard ratio (HR) = 2.47, 95% confidence interval (CI) = 1.37-5.65, P = 0.0047]. Patients with high-miR-21 expression also had a shorter median DFS (10.9 versus 29.9 months, P = 0.01). Multivariate analysis confirmed miR-21 as independently prognostic for mortality and disease progression (death risk: HR = 3.3, 95% CI = 1.5-7.0, P = 0.02; progression risk: HR = 2.3, 95% CI = 1.2-4.8, P = 0.02), as well as positive lymph-node status (death risk: HR = 2.6, 95% CI = 1.1-6.3, P = 0.03; progression risk: HR = 2.2, 95% CI = 1.0-4.8, P = 0.04). CONCLUSIONS: miR-21, miR-155 and miR-101 showed significant differences in invasive versus non-invasive IPMNs. miR-21 emerged as an independent prognostic biomarker in invasive IPMNs and should be validated in prospective studies.

Sub-micrometric liposomes as drug delivery systems in the treatment of periodontitis.

Periodontitis is a complex disease and bacterial infection is one of the most common factors involved in this disease. Current strategies for the local delivery of antibiotics do not allow a complete clearance of bacteria filling dentinal tubules and this limits their therapeutic efficacy. Therefore, there is a strong need for the development of new delivery strategies aimed at improving the efficacy of antibiotic therapy for periodontitis with special reference to their ability to penetrate into the tubules. The aim of the present study is to develop liposome-based delivery systems of sub-micron dimension, able to diffuse into the dentinal tubules. A further aim of the research is to develop a protocol for enhanced diffusion based on the use of magnetic liposomes and magnetic fields. Liposomes were produced by hydration of a pre-liposomal formulation. The vesicles were stabilised with PEG and their re-sizing was achieved by extrusion. Magnetite nanoparticles were synthesized inside the vesicles, i.e., the chemical reaction involving FeCl2, FeCl3 and NH3 occurred within the core of the newly formed liposomes. Dynamic light scattering analysis was performed for size characterization. A mathematical model was implemented to predict the diffusion of the liposomes in dentinal tubules. Ex-vivo validation was performed on extracted human teeth. We produced PEG-ylated liposomes (average size 204.3 nm) and PEG-ylated magnetic liposomes (average size 286 nm) and an iron content of 4.2 µg/ml. Through mathematical modelling, we deduced that sub-micrometer vesicles are able to penetrate into dentinal tubules. This penetration is considerably more effective when the vesicles are magnetized and subjected to an external magnetic field which accelerates their movement within the tubules. The liposome-based delivery systems developed by the present study are able to penetrate deeply into the tubules, sometimes reaching their terminal ends.

Study of apoptosis induction and deoxycytidine kinase/cytidine deaminase modulation in the synergistic interaction of a novel ceramide analog and gemcitabine in pancreatic cancer cells.

This study investigated the interaction between the novel ceramide analog AL6 and gemcitabine in MIA PaCa-2 and PANC-1 pancreatic cancer cell lines, harboring different polymorphic variants of the gemcitabine catabolism enzyme cytidine deaminase (CDA). AL6 dose-dependently inhibited cell growth, induced apoptosis and synergistically enhanced the cytotoxic activity of gemcitabine. Moreover, it triggered apoptosis, which was significantly enhanced by the combination, and increased the ratio between gene expression of the activating enzyme deoxycytidine kinase (dCK) and CDA, potentially favoring gemcitabine activity. In conclusion, AL6 displays synergistic cytotoxic activity, enhances apoptosis, and favorably modulates enzymes involved in gemcitabine metabolism, supporting future investigation of this combination in pancreatic cancer.

Persistent correction of hyperglycemia in streptozotocin-nicotinamide-induced diabetic mice by a non-conventional radical scavenger.

We previously reported that in a diabetes mouse model, characterised by moderate hyperglycaemia and reduced beta-cell mass, the radical scavenger bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl)decandioate di-hydrochloride (IAC), a non-conventional cyclic hydroxylamine derivative, improves metabolic alterations by counteracting beta-cell dysfunction associated with oxidative stress. The aims of this study were to ascertain whether the beneficial effects of IAC treatment could be maintained after its discontinuation and further elucidate the underlying mechanisms. Diabetes was induced in C57Bl/6J mice by streptozotocin (STZ) and nicotinamide (NA) administration. Diabetic mice were treated for 7 weeks with various doses of IAC (7.5, 15, or 30 mg/kg b.w./die i.p.) and monitored for additional 8 weeks after suspension of IAC. Then, pancreatic tissue was used for determination of beta-cell mass by immunohistochemistry and beta-cell ultrastructural analysis. STZ-NA mice showed moderate hyperglycaemia, glucose intolerance and reduced beta-cell mass (25% of controls). IAC-treated STZ-NA mice (at both doses of 15 and 30 mg/kg b.w.) showed long-term reduction of hyperglycaemia even after discontinuation of treatment, attenuation of glucose intolerance and partial preservation of beta-cell mass. The lowest IAC dose was much less effective. Plasma nitrotyrosine levels (an oxidative stress index) significantly increased in untreated diabetic mice and were lowered upon IAC treatment. At ultrastructural level, beta cells of IAC-treated diabetic mice were protected against degranulation and mitochondrial alterations. In the STZ-NA diabetic mouse model, the radical scavenger IAC induces a prolonged reduction of hyperglycaemia associated with partial restoration of beta-cell mass and function, likely dependent on blockade of oxidative stress-induced damaging mechanisms.

Inflammatory cells contribute to the generation of an angiogenic phenotype in pancreatic ductal adenocarcinoma.

BACKGROUND: Inflammatory cells contribute to the growth and spread of human malignancies by producing molecules that enhance tumour invasiveness. AIMS: To characterise the inflammatory infiltrate in pancreatic ductal adenocarcinoma and to analyse its contribution to angiogenesis and its prognostic relevance. METHODS: Immunohistochemistry was used to identify inflammatory cells and evaluate the expression of proangiogenic and prolymphangiogenic molecules (vascular endothelial growth factor A (VEGF-A), VEGF-C, and basic fibroblast growth factor (bFGF)) by inflammatory and cancer cells in 137 pancreatic cancers. Intratumorous microvessel density (IMD) was assessed using CD34 as an endothelial cell marker. RESULTS: There were significantly more mast cells and macrophages in pancreatic cancers than in normal pancreas and the number of mast cells directly correlated with the presence of lymph node metastases. However, there was no relation between numbers of infiltrating inflammatory cells and the presence of chronic pancreatitis (CP)-like changes in the parenchyma surrounding the tumour. Double immunostaining revealed that both pancreatic mast cells and macrophages express VEGF-A, VEGF-C, and bFGF. These factors were also expressed in the tumour cells in many cases. The numbers of VEGF-A expressing tumour cells and bFGF expressing tumour and inflammatory cells significantly correlated with IMD. Moreover, tumours with higher IMD had higher numbers of infiltrating mast cells and macrophages. CONCLUSIONS: Mononuclear inflammatory cells of the non-specific immune response are recruited to pancreatic cancer tissues independent of the presence of CP-like changes, may influence the metastatic capacity of the cancer cells, and may contribute to the development of tumours with high angiogenic activity.