State of the art biological therapies in pancreatic cancer

Photodynamic Stromal Depletion in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest solid malignancies, with a five-year survival of less than 10%. The resistance of the disease and the associated lack of therapeutic response is attributed primarily to its dense, fibrotic stroma, which acts as a barrier to drug perfusion and permits tumour survival and invasion. As clinical trials of chemotherapy (CT), radiotherapy (RT), and targeted agents have not been successful, improving the survival rate in unresectable PDAC remains an urgent clinical need. Photodynamic stromal depletion (PSD) is a recent approach that uses visible or near-infrared light to destroy the desmoplastic tissue. Preclinical evidence suggests this can resensitise tumour cells to subsequent therapies whilst averting the tumorigenic effects of tumour-stromal cell interactions. So far, the pre-clinical studies have suggested that PDT can successfully mediate the destruction of various stromal elements without increasing the aggressiveness of the tumour. However, the complexity of this interplay, including the combined tumour promoting and suppressing effects, poses unknowns for the clinical application of photodynamic stromal depletion in PDAC.

Impact of exosome therapy on pancreatic cancer and its progression

Pancreatic cancer, one of the most aggressive tumors, has a dismal prognosis because of the low rates of early identification, fast progression, difficulties following surgery, and the ineffectiveness of current oncologic therapies. There are no imaging techniques or biomarkers that can accurately identify, categorize, or predict the biological behavior of this tumor. Exosomes are extracellular vesicles that play a crucial rule in the progression, metastasis, and chemoresistance of pancreatic cancer. They have been verified to be potential biomarkers for pancreatic cancer management. Studying the role of exosomes in pancreatic cancer is substantial. Exosomes are secreted by most eukaryotic cells and participated in intercellular communication. The components of exosomes, including proteins, DNA, mRNA, microRNA, long non-coding RNA, circular RNA, etc., play a crucial role in regulating tumor growth, metastasis, and angiogenesis in the process of cancer development, and can be used as a prognostic marker and/or grading basis for tumor patients. Hereby, in this concise review, we intend to summarize exosomes components and isolation, exosome secretion, function, importance of exosomes in the progression of pancreatic cancer and exosomal miRNAs as possible pancreatic cancer biomarkers. Finally, the application potential of exosomes in the treatment of pancreatic cancer, which provides theoretical supports for using exosomes to serve precise tumor treatment in the clinic, will be discussed.

Recent advances in targeted therapy for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is a fatal disease with a 5-year survival rate of 8% and a median survival of 6 mo. In PDAC, several mutations in the genes are involved, with Kirsten rat sarcoma oncogene (90%), cyclin-dependent kinase inhibitor 2A (90%), and tumor suppressor 53 (75%–90%) being the most common. Mothers against decapentaplegic homolog 4 represents 50%. In addition, the self-preserving cancer stem cells, dense tumor microenvironment (fibrous accounting for 90% of the tumor volume), and suppressive and relatively depleted immune niche of PDAC are also constitutive and relevant elements of PDAC. Molecular targeted therapy is widely utilized and effective in several solid tumors. In PDAC, targeted therapy has been extensively evaluated; however, survival improvement of this aggressive disease using a targeted strategy has been minimal. There is currently only one United States Food and Drug Administration-approved targeted therapy for PDAC – erlotinib, but the absolute benefit of erlotinib in combination with gemcitabine is also minimal (2 wk). In this review, we summarize current targeted therapies and clinical trials targeting dysregulated signaling pathways and components of the PDAC oncogenic process, analyze possible reasons for the lack of positive results in clinical trials, and suggest ways to improve them. We also discuss emerging trends in targeted therapies for PDAC: combining targeted inhibitors of multiple pathways. The PubMed database and National Center for Biotechnology Information clinical trial website (www.clinicaltrials.gov) were queried to identify completed and published (PubMed) and ongoing (clinicaltrials.gov) clinical trials (from 2003-2022) using the keywords pancreatic cancer and targeted therapy. The PubMed database was also queried to search for information about the pathogenesis and molecular pathways of pancreatic cancer using the keywords pancreatic cancer and molecular pathways.

An EGFR/HER2-targeted conjugate sensitizes gemcitabine-sensitive and resistant pancreatic cancer through different SMAD4-mediated mechanisms

Chemoresistance limits its clinical implementation for pancreatic ductal adenocarcinoma (PDAC). We previously generated an EGFR/HER2 targeted conjugate, dual-targeting ligand-based lidamycin (DTLL), which shows a highly potent antitumor effect. To overcome chemoresistance in PDAC, we aim to study DTLL efficacy when combined with gemcitabine and explore its mechanisms of action. DTLL in combination with gemcitabine show a superior inhibitory effect on the growth of gemcitabine-resistant/sensitive tumors. DTLL sensitizes gemcitabine efficacy via distinct action mechanisms mediated by mothers against decapentaplegic homolog 4 (SMAD4). It not only prevents neoplastic proliferation via ATK/mTOR blockade and NF-κB impaired function in SMAD4-sufficient PDACs, but also restores SMAD4 bioactivity to trigger downstream NF-κB-regulated signaling in SMAD4-deficient tumors and to overcome chemoresistance. DTLL seems to act as a SMAD4 module that normalizes its function in PDAC, having a synergistic effect in combination with gemcitabine. Our findings provide insight into a rational SMAD4-directed precision therapy in PDAC.

Cancer Associated Fibroblast (CAF) Regulation of PDAC Parenchymal (CPC) and CSC Phenotypes Is Modulated by ECM Composition

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of all cancers, having one of the lowest five-year survival rates. One of its hallmarks is a dense desmoplastic stroma consisting in the abnormal accumulation of extracellular matrix (ECM) components, especially Collagen I. This highly fibrotic stroma embeds the bulk cancer (parenchymal) cells (CPCs), cancer stem cells (CSCs) and the main producers of the stromal reaction, the Cancer Associated Fibroblasts (CAFs). Little is known about the role of the acellular ECM in the interplay of the CAFs with the different tumor cell types in determining their phenotypic plasticity and eventual cell fate.

METHODS

Here, we analyzed the role of ECM collagen I in modulating the effect of CAF-derived signals by incubating PDAC CPCs and CSCs grown on ECM mimicking early (low collagen I levels) and late (high collagen I levels) stage PDAC stroma with conditioned medium from primary cultured CAFs derived from patients with PDAC in a previously described three-dimensional (3D) organotypic model of PDAC.

RESULTS

We found that CAFs (1) reduced CPC growth while favoring CSC growth independently of the ECM; (2) increased the invasive capacity of only CPCs on the ECM mimicking the early tumor; and (3) favored vasculogenic mimicry (VM) especially of the CSCs on the ECM mimicking an early tumor.

CONCLUSIONS

We conclude that the CAFs and acellular stromal components interact to modulate the tumor behaviors of the PDAC CPC and CSC cell types and drive metastatic progression by stimulating the phenotypic characteristics of each tumor cell type that contribute to metastasis.

AQP5 Is a Novel Prognostic Biomarker in Pancreatic Adenocarcinoma

Background

Pancreatic adenocarcinoma (PAAD) is a highly malignant tumor with a poor prognosis. The identification of effective molecular markers is of great significance for diagnosis and treatment. Aquaporins (AQPs) are a family of water channel proteins that exhibit several properties and play regulatory roles in human carcinogenesis. However, the association between Aquaporin-5 (AQP5) expression and prognosis and tumor-infiltrating lymphocytes in PAAD has not been reported.

Methods

AQP5 mRNA expression, methylation, and protein expression data in PAAD were analyzed using GEPIA, UALCAN, HAP, METHSURV, and UCSC databases. AQP5 expression in PAAD patients and cell lines from our cohort was examined using immunohistochemistry and Western blotting. The LinkedOmics database was used to study signaling pathways related to AQP5 expression. TIMER and TISIDB were used to analyze correlations among AQP5, tumor-infiltrating immune cells, and immunomodulators. Survival was analyzed using TCGA and Kaplan-Meier Plotter databases.

Results

In this study, we investigated AQP5 expression in PAAD and determined whether the expression of AQP5 is a strong prognostic biomarker for PAAD. We searched and analyzed public cancer databases (GEO, TCGA, HAP, UALCAN, GEPIA, etc.) to conclude that AQP5 expression levels were upregulated in PAAD. Kaplan-Meier curve analysis showed that high AQP5 expression positively correlated with poor prognosis. Using TIMER and TISIDB, we found that the expression of AQP5 was associated with different tumor-infiltrating immune cells, especially macrophages. We found that hypomethylation of the AQP5 promoter region was responsible for its high expression in PAAD.

Conclusions

AQP5 can serve as a novel biomarker to predict prognosis and immune infiltration in PAAD.

Transmembrane Protein 170B is a Prognostic Biomarker and Associated With Immune Infiltrates in Pancreatic Adenocarcinoma

Background: Pancreatic adenocarcinoma (PAAD) is among the most common types of cancer with a poor prognosis. Transmembrane protein 170B (TMEM170B) has been reported to suppress breast cancer proliferation, metastasis, and tumorigenesis and is related to prognosis. However, its role in PAAD and the underlying molecular mechanisms are yet to be investigated.

Patients and methods: We performed a comprehensive analysis of RNA sequencing data obtained from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases to determine TMEM170B expression. Immunostaining and real-time polymerase chain reaction (RT-PCR) were done to determine TMEM170B expression in human pancreatic cancer cell lines and tissue specimens. Furthermore, the correlation of TMEM170B with clinicopathological features and PAAD prognosis was investigated, and the mechanisms were explored through enrichment analysis and immune cell infiltration analysis.

Results: TCGA and GEO dataset analysis revealed that TMEM170B expression in PAAD tissue samples was significantly lower than that in non-tumorous tissues, which was further confirmed by immunohistochemistry and RT-PCR. Low TMEM170B expression was associated with poor differentiation (p = 0.014). Multivariate analysis identified that TMEM170B is an independent indicator for overall survival [hazard ratio (HR) = 0.116, 95% confidence interval (CI) = 0.014–0.995; p = 0.049] and disease-free survival (HR = 0.19, 95% CI = 0.04–0.910; p = 0.038) in patients with PAAD. Additionally, TMEM170B was involved in immune-related gene sets, including those related to chemokine signaling pathways and innate and adaptive immunity. High TMEM170B expression was linked to antitumor immune microenvironment with a high infiltration of B cells, T cells, dendritic cells, monocytes, M1 macrophages, neutrophil, and natural killer cells and a low infiltration of Tregs and myeloid-derived suppressor cells (all p < 0.05).

Plain Language Summary: There is an urgent need to identify clinical prognostic biomarkers and targeted drugs for pancreatic cancer treatment. In this study, the expression status and prognostic value of transmembrane protein 170B (TMEM170B) in pancreatic adenocarcinoma were elucidated. Furthermore, TMEM170B, as a tumor suppressor gene, induced antitumor immune effects, including increased tumor infiltration of immune effector cells and reduced levels of inhibitory immune molecules and regulatory cells. Therefore, TMEM170B could be regarded as a novel target in preventing the progression of pancreatic cancer.

Conclusion: The findings suggest that low TMEM170B expression is remarkably correlated with poor PAAD prognosis, which might provide a therapeutic target for PAAD.

Pivotal antitumor role of the immune checkpoint molecule B7-H1 in pancreatic cancer

Immune checkpoint molecule B7-H1 plays a decisive immune regulatory role in different pathologies including cancer, and manipulation of B7-H1 expression became an attractive approach in cancer immunotherapy. Pancreatic cancer (PDAC) is characterized by pronounced immunosuppressive environment and B7-H1 expression correlates with PDAC prognosis. However, the first attempts to diminish B7-H1 expression in patients were not so successful. This points the complicity of PDAC immunosuppressive network and requires further examinations. We investigated the effect of B7-H1 deficiency in PDAC. Our results clearly show that partial or complete B7-H1 inhibition in vivo let to reduced tumor volume and improved survival of PDAC-bearing mice. This oncological benefit is due to the abrogation of immunosuppression provided by MDSC, macrophages, DC and Treg, which resulted in simultaneous restoration of anti-tumor immune response, namely improved accumulation and functionality of effector-memory CD4 and CD8 T cells. Our results underline the potential of B7-H1 molecule to control immunosuppressive network in PDAC and provide new issues for further clinical investigations.

LMO7 as an Unrecognized Factor Promoting Pancreatic Cancer Progression and Metastasis

Pancreatic cancer (PC) is one of the most lethal human malignancies without effective treatment. In an effort to discover key genes and molecular pathways underlying PC growth, we have identified LIM domain only 7 (LMO7) as an under-investigated molecule, which highly expresses in primary and metastatic human and mouse PC with the potential of impacting PC tumorigenesis and metastasis. Using genetic methods with siRNA, shRNA, and CRISPR-Cas9, we have successfully generated stable mouse PC cells with LMO7 knockdown or knockout. Using these cells with loss of LMO7 function, we have demonstrated that intrinsic LMO7 defect significantly suppresses PC cell proliferation, anchorage-free colony formation, and mobility in vitro and slows orthotopic PC tumor growth and metastasis in vivo. Mechanistic studies demonstrated that loss of LMO7 function causes PC cell-cycle arrest and apoptosis. These data indicate that LMO7 functions as an independent and unrecognized druggable factor significantly impacting PC growth and metastasis, which could be harnessed for developing a new targeted therapy for PC.

Bioinformatics analysis combined with experiments to explore potential prognostic factors for pancreatic cancer

Background

Pancreatic cancer is a common malignant tumor of the digestive tract. It has a high degree of malignancy and poor prognosis. Finding effective molecular markers has great significance for pancreatic cancer diagnosis and treatment. This study aimed to investigate DLGAP5 expression in pancreatic cancer and explore the possible mechanisms and clinical value of DLGAP5 in tumorigenesis and tumor development.

Methods

Differentially expressed genes were screened using the Gene Expression Omnibus (GEO) data set GSE16515. Gene Ontology (GO)-based functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis were performed on the corresponding proteins of the above genes using the Database for Annotation, Visualization, and Integrated Discovery (DAVID). The Kaplan–Meier Plotter database was used to analyze the relationship between differentially expressed genes and pancreatic cancer prognosis. The most prognostic gene, DLGAP5, was screened out, and the Oncomine and gene expression profiling interactive analysis (GEPIA) databases were used to analyze its expression in pancreatic cancer and other cancer tissues. The Cancer Genome Atlas (TCGA) database was used to analyze the overall survival of DLGAP5. Gene set enrichment analysis (GSEA) was performed to explore its possible molecular mechanisms in pancreatic cancer. Furthermore, the biological behavior of DLGAP5 in pancreatic cancer was verified by cell function experiments.

Results

A total of 201 significant upregulated differentially expressed genes and 79 downregulated genes were selected. The biological processes with significant enrichment of differential genes included cell adhesion, apoptosis, wound healing, leukocyte migration, angiogenesis. Pathways were mainly enriched in tumor-related signaling pathways such as cancer pathways, the extracellular matrix-receptor interaction pathway, and the p53 signaling pathway. DLGAP5 was significantly expressed in pancreatic cancer, and its expression level had a significant effect on patients’ survival time and progression-free survival. GSEA results indicated that DLGAP5 had significantly enriched into signaling pathways such as the cell cycle, the p53 signaling pathway, and oocyte meiosis. The experimental results showed that when we knocked down the expression of DLGAP5 in pancreatic cancer cells, their proliferation ability was significantly inhibited, and their invasion and migration ability significantly decreased.

Conclusions

DLGAP5 can be used as a prognostic indicator for pancreatic cancer and affect the occurrence and development of pancreatic cancer.

Durvalumab With or Without Tremelimumab for Patients With Metastatic Pancreatic Ductal Adenocarcinoma: A Phase 2 Randomized Clinical Trial

Importance

New therapeutic options for patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) are needed. This study evaluated dual checkpoint combination therapy in patients with mPDAC.

Objective

To evaluate the safety and efficacy of the anti-PD-L1 (programmed death-ligand 1) antibody using either durvalumab monotherapy or in combination with the anticytotoxic T-lymphocyte antigen 4 antibody using durvalumab plus tremelimumab therapy in patients with mPDAC.

Design, Setting, and Participants

Part A of this multicenter, 2-part, phase 2 randomized clinical trial was a lead-in safety, open-label study with planned expansion to part B pending an efficacy signal from part A. Between November 26, 2015, and March 23, 2017, 65 patients with mPDAC who had previously received only 1 first-line fluorouracil-based or gemcitabine-based treatment were enrolled at 21 sites in 6 countries. Efficacy analysis included the intent-to-treat population; safety analysis included patients who received at least 1 dose of study treatment and for whom any postdose data were available.

Interventions

Patients received durvalumab (1500 mg every 4 weeks) plus tremelimumab (75 mg every 4 weeks) combination therapy for 4 cycles followed by durvalumab therapy (1500 mg every 4 weeks) or durvalumab monotherapy (1500 mg every 4 weeks) for up to 12 months or until the onset of progressive disease or unacceptable toxic effects.

Main Outcomes and Measures

Safety and efficacy were measured by objective response rate, which was used to determine study expansion to part B. The threshold for expansion was an objective response rate of 10% for either treatment arm.

Results

Among 65 randomized patients, 34 (52%) were men and median age was 61 (95% CI, 37-81) years. Grade 3 or higher treatment-related adverse events occurred in 7 of 32 patients (22%) receiving combination therapy and in 2 of 32 patients (6%) receiving monotherapy; 1 patient randomized to the monotherapy arm did not receive treatment owing to worsened disease. Fatigue, diarrhea, and pruritus were the most common adverse events in both arms. Overall, 4 of 64 patients (6%) discontinued treatment owing to treatment-related adverse events. Objective response rate was 3.1% (95% CI, 0.08-16.22) for patients receiving combination therapy and 0% (95% CI, 0.00-10.58) for patients receiving monotherapy. Low patient numbers limited observation of the associations between treatment response and PD-L1 expression or microsatellite instability status.

Conclusion and Relevance

Treatment was well tolerated, and the efficacy of durvalumab plus tremelimumab therapy and durvalumab monotherapy reflected a population of patients with mPDAC who had poor prognoses and rapidly progressing disease. Patients were not enrolled in part B because the threshold for efficacy was not met in part A.

Trial Registration

ClinicalTrials.gov identifier: NCT02558894.

Proteogenomic Network Analysis of Context-Specific KRAS Signaling in Mouse-to-Human Cross-Species Translation

The highest frequencies of KRAS mutations occur in colorectal carcinoma (CRC) and pancreatic ductal adenocarcinoma (PDAC). The ability to target downstream pathways mediating KRAS oncogenicity is limited by an incomplete understanding of the contextual cues modulating the signaling output of activated K-RAS. We performed mass spectrometry on mouse tissues expressing wild-type or mutant Kras to determine how tissue context and genetic background modulate oncogenic signaling. Mutant Kras dramatically altered the proteomes and phosphoproteomes of preneoplastic and neoplastic colons and pancreases in a context-specific manner. We developed an approach to statistically humanize the mouse networks with data from human cancer and identified genes within the humanized CRC and PDAC networks synthetically lethal with mutant KRAS. Our studies demonstrate the context-dependent plasticity of oncogenic signaling, identify non-canonical mediators of KRAS oncogenicity within the KRAS-regulated signaling network, and demonstrate how statistical integration of mouse and human datasets can reveal cross-species therapeutic insights.

Targeted therapies in pancreatic cancer: Promises and failures

Pancreatic ductal adenocarcinoma (PDAC) is an incidence rate nearly equal to its mortality rate. The poor prognosis of the disease can be explained by the absence of effective biomarkers for screening and early detection, together with the aggressive behavior and resistance to the currently available chemotherapy. The therapeutic failure can also be attributed to the inter-/intratumor genetic heterogeneity and the abundance of tumor stroma that occupies the majority of the tumor mass. Gemcitabine is used in the treatment of PDAC; however, the response rate is less than 12%. A recent phase III trial revealed that the combination of oxaliplatin, irinotecan, fluorouracil, and leucovorin could be an option for the treatment of metastatic PDAC patients with good performance status, although these approaches can result in high toxicity level. Further investigations are required to develop innovative anticancer agents that either improve gemcitabine activity, within novel combinatorial approaches or acts with a better efficacy than gemcitabine. The aim of the current review is to give an overview of preclinical and clinical studies targeting key dysregulated signaling pathways in PDAC.

LncRNA DLX6-AS1 promoted cancer cell proliferation and invasion by attenuating the endogenous function of miR-181b in pancreatic cancer

Background

Pancreatic cancer, one of the most aggressive malignancies, ranks the fourth cause of cancer-related death worldwide. Aberrantly expressed long non-coding RNAs (lncRNAs) functioned as oncogenes or tumor suppressors in pancreatic cancer. This study aimed to determine the expression of lncRNA DLX6 antisense RNA 1 (DLX6-AS1) in pancreatic cancer tissues and to explore the DLX6-AS1-related pathway in pancreatic cancer.

Materials and methods

The gene expression levels were determined by quantitative real-time PCR, and protein expression levels were determined by western blot assay. CCK-8 assay, colony formation assay and Transwell migration and invasion assays were used to examine cell proliferation, migration and invasion. Luciferase reporter assay was used to confirm the binding between DLX6-AS1and its potential targets. In vivo study used the mouse xenograft model to test the anti-tumor effect of DLX6-AS1 knockdown.

Results

The high expression of DLX6-AS1 was observed in pancreatic cancer tissues, and high expression of DLX6-AS1 was positively correlated with larger tumor size, advanced TNM stage and lymph node metastasis. Knockdown of DLX6-AS1 dramatically impaired cancer cell proliferation, migration and invasion. MiR-181b was the downstream target of DLX6-AS1. Knockdown of miR-181b reversed the suppression of cell viability, migration and invasion abilities caused by DLX6-AS1 knockdown. MiR-181b was found to target Zinc finger E-box-binding homeobox 2 and to modulate epithelial-mesenchymal transition. Furthermore, DLX6-AS1 knockdown inhibited tumor growth and tumor metastasis in vivo.

Conclusion

Collectively, our data suggested that DLX6-AS1 promotes cancer cell proliferation and invasion by attenuating the endogenous function of miR-181b in pancreatic cancer.

Signal-Targeted Therapies and Resistance Mechanisms in Pancreatic Cancer: Future Developments Reside in Proteomics

For patients with metastatic pancreatic cancer that are not eligible for surgery, signal-targeted therapies have so far failed to significantly improve survival. These therapeutic options have been tested in phase II/III clinical trials mostly in combination with the reference treatment gemcitabine. Innovative therapies aim to annihilate oncogenic dependency, or to normalize the tumoural stroma to allow immune cells to function and/or re-vascularisation to occur. Large scale transcriptomic and genomic analysis revealed that pancreatic cancers display great heterogeneity but failed to clearly delineate specific oncogene dependency, besides oncogenic Kras. Beyond these approaches, proteomics appears to be an appropriate approach to classify signal dependency and to identify specific alterations at the targetable level. However, due to difficulties in sampling, proteomic data for this pathology are scarce. In this review, we will discuss the current state of clinical trials for targeted therapies against pancreatic cancer. We will then highlight the most recent proteomic data for pancreatic tumours and their metastasis, which could help to identify major oncogenic signalling dependencies, as well as provide future leads to explain why pancreatic tumours are intrinsically resistant to signal-targeted therapies. We will finally discuss how studies on phosphatidylinositol-3-kinase (PI3K) signalling, as the paradigmatic pro-tumoural signal downstream of oncogenic Kras in pancreatic cancer, would benefit from exploratory proteomics to increase the efficiency of targeted therapies.

Extracellular matrix composition modulates PDAC parenchymal and stem cell plasticity and behavior through the secretome

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Its aggressiveness is driven by an intense fibrotic desmoplastic reaction in which the increasingly collagen I-rich extracellular matrix (ECM) and several cell types, including cancer stem cells (CSCs), create a tumor-supportive environment. However, how ECM composition regulates CSC dynamics and their relationship with the principle parenchymal tumor population to promote early invasive growth is not yet characterized. For this, we utilized a platform of 3D organotypic cultures composed of laminin-rich Matrigel, representative of an early tumor, plus increasing concentrations of collagen I to simulate malignant stroma progression. As ECM collagen I increases, CSCs progress from a rapidly growing, vascular phenotype to a slower growing, avascular phase, while maintaining their endothelial-like gene signatures. This transition is supported autocrinically by the CSCs and paracrinically by the parenchymal cells via their ECM-dependent secretomes. Indeed, when growing on an early tumor ECM, the CSCs are dedicated toward the preparation of a vascular niche by (a) activating their growth program, (b) secreting high levels of proangiogenic factors which stimulate both angiogenesis and vasculogenic mimicry, and (c) overexpressing VEGFR-2, which is activated by VEGF secreted by both the CSC and parenchymal cells. On Matrigel, the more differentiated parenchymal tumor cell population had reduced growth but a high invasive capacity. This concerted high local invasion of parenchymal cells into the CSC-derived vascular network suggests that a symbiotic relationship between the parenchymal cells and the CSCs underlies the initiation and maintenance of early PDAC infiltration and metastasis.

Amphiphilic nanocarrier-induced modulation of PLK1 and miR-34a leads to improved therapeutic response in pancreatic cancer

The heterogeneity of pancreatic ductal adenocarcinoma (PDAC) suggests that successful treatment might rely on simultaneous targeting of multiple genes, which can be achieved by RNA interference-based therapeutic strategies. Here we show a potent combination of microRNA and siRNA delivered by an efficient nanocarrier to PDAC tumors. Using proteomic-microRNA profiles and survival data of PDAC patients from TCGA, we found a novel signature for prolonged survival. Accordingly, we used a microRNA-mimic to increase miR-34a together with siRNA to silence PLK1 oncogene. For in vivo dual-targeting of this combination, we developed a biodegradable amphiphilic polyglutamate amine polymeric nanocarrier (APA). APA-miRNA-siRNA polyplexes systemically administered to orthotopically inoculated PDAC-bearing mice showed no toxicity and accumulated at the tumor, resulting in an enhanced antitumor effect due to inhibition of MYC oncogene, a common target of both miR-34a and PLK1. Taken together, our findings warrant this unique combined polyplex's potential as a novel nanotherapeutic for PDAC.

Dynamic contrast-enhanced MRI of the microenvironment of pancreatic adenocarcinoma xenografts

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with poor outcome. Resistance to treatment is associated with impaired vascularity, extensive hypoxia, and interstitial hypertension. In this study, the potential of dynamic contrast-enhanced (DCE)-MRI as a method for assessing the microvascular density (MVD), the fraction of hypoxic tissue, and the interstitial fluid pressure (IFP) of PDACs was investigated.

MATERIAL AND METHODS

Intramuscular BxPC-3, Capan-2, MIAPaCa-2, and Panc-1 PDAC xenografts were used as preclinical models of human PDACs. DCE-MRI with Gd-DOTA as contrast agent was conducted with a 7.05-T scanner, and the DCE-MRI series were analyzed voxelwise by using the Tofts pharmacokinetic model. Tumor MVD and hypoxia were measured in histological preparations by using pimonidazole as a hypoxia marker and CD31 as a marker of endothelial cells. IFP was measured with a Millar catheter.

RESULTS

K^trans (the volume transfer constant of Gd-DOTA) increased with increasing MVD and decreased with increasing hypoxic fraction, but was not associated with IFP. Any association between v_e (the fractional distribution volume of Gd-DOTA) and MVD, hypoxic fraction, or IFP could not be detected.

CONCLUSIONS

This study shows that DCE-MRI is a useful modality for assessing important features of the microenvironment of PDAC xenografts and thus provides the basis for future preclinical and clinical DCE-MRI investigations of PDAC.

Detecting circulating tumor material and digital pathology imaging during pancreatic cancer progression

Pancreatic cancer (PC) is a leading cause of cancer-related death worldwide. Clinical symptoms typically present late when treatment options are limited and survival expectancy is very short. Metastatic mutations are heterogeneous and can accumulate up to twenty years before PC diagnosis. Given such genetic diversity, detecting and managing the complex states of disease progression may be limited to imaging modalities and markers present in circulation. Recent developments in digital pathology imaging show potential for early PC detection, making a differential diagnosis, and predicting treatment sensitivity leading to long-term survival in advanced stage patients. Despite large research efforts, the only serum marker currently approved for clinical use is CA 19-9. Utility of CA 19-9 has been shown to improve when it is used in combination with PC-specific markers. Efforts are being made to develop early-screening assays that can detect tumor-derived material, present in circulation, before metastasis takes a significant course. Detection of markers that identify circulating tumor cells and tumor-derived extracellular vesicles (EVs) in biofluid samples offers a promising non-invasive method for this purpose. Circulating tumor cells exhibit varying expression of epithelial and mesenchymal markers depending on the state of tumor differentiation. This offers a possibility for monitoring disease progression using minimally invasive procedures. EVs also offer the benefit of detecting molecular cargo of tumor origin and add the potential to detect circulating vesicle markers from tumors that lack invasive properties. This review integrates recent genetic insights of PC progression with developments in digital pathology and early detection of tumor-derived circulating material.

Multimodal treatment of resectable pancreatic ductal adenocarcinoma

After a timing preoperative staging, treatment of resectable pancreatic adenocarcinoma (PDAC) includes surgery and adjuvant therapies, the former representing the initial therapeutic option and the latter aiming to reduce the incidence of both distant metastases (chemotherapy) and locoregional failures (chemoradiotherapy). Herein, we provide a critical overview on the role of multimodal treatment in PDAC and on new opportunities related to current more active poli-chemotherapy regimens, targeted therapies, and the more recent immunotherapy approaches. Moreover, an analysis of pathological markers and clinical features able to help clinicians in the selection of the best therapeutic strategy will be discussed. Lastly, the role of neoadjuvant treatment of initially resectable disease will be considered mostly in patients whose malignancy shows morphological but not clinical or biological criteria of resectability. Depending on the results of these investigational studies, today a multidisciplinary approach can offer the best address therapy for these patients.

Study on the mitochondrial apoptosis pathways of small cell lung cancer H446 cells induced by Trichinella spiralis muscle larvae ESPs

Trichinella spiralis (T.spiralis) muscle-larva (ML) excretory-secretory proteins (ESPs) contain antitumour-active substances. ESPs have been shown to inhibit tumour growth. To explore the effects of these proteins on small cell lung cancer cells and the possible mechanisms of their antineoplastic action, H446 SCLC cells were co-cultured with different concentrations of T. spiralis ML ESPs for 12, 24 and 48 h. Our results showed that T. spiralis ML ESPs significantly inhibited H446 cell proliferation, which was dose-and time-dependent. The results of flow cytometry testing indicate a clear apoptosis trend in H446 cells co-cultured with ESPs for 24 h. Reverse transcription polymerase chain reaction and Western blotting results showed increased expression of pro-apoptosis genes Bax, Cyt-C, Apaf-1, caspase-9 and caspase-3, compared with the negative control group, and decreased the expression of anti-apoptosis genes Bcl-2 and Livin. Our results suggest that T. spiralis ML ESPs can induce apoptosis in H446 cells through a mitochondrial pathway, which may be a mechanism of antineoplastic action in T. spiralis ML ESPs.

Available technologies and clinical applications of targeted chemotherapy in pancreatic cancer

The incidence of pancreatic cancer, the fourth leading cause of cancer death in United States, is increasing worldwide. Even though the cure rate has doubled in 40 years, it is abysmally poor at 6-7%. As surgical resection remains the only curative treatment and less than 20% of the newly diagnosed cancers are resectable, the major burden of disease management lies in early diagnosis, good prognostication, and proper neo-adjuvant and/or adjuvant therapy. With advancing technologies and their ease of availability, researchers have better tools to understand pancreatic cancer. In the post-genetic era, proteomic, phosphoproteomic, metabolomic, and more have brought us to a multi-omics era. These newer avenues bring promises of better screening modalities, less invasive diagnostics and monitoring, subtyping of pancreatic cancer, and fine tuning the treatment modalities not only to the right stage of tumor but also to the right tumor biology. As the multitudes of technologies are generating extensive amounts of incongruous data, they are giving clinicians a lot of non-actionable information. In this paper, we wish to encompass the newer technologies, sub-classifications, and future treatment modalities in personalized care of patients with pancreatic cancer.

Modified irinotecan and infusional 5-fluorouracil (mFOLFIRI) in patients with refractory advanced pancreas cancer (APC): a single-institution experience

Pancreatic adenocarcinoma is the fourth leading cause of cancer death. Recently, MM-398 (nanoliposomal irinotecan) was shown to be associated with significant improvement in outcome measures with acceptable toxicities when combined with 5-fluorouracil (5-FU)/leucovorin (LV) compared to 5-FU/LV alone in patients failing one line of gemcitabine-based therapy. There is a paucity of data evaluating the role of irinotecan in combination with 5FU in advanced pancreas cancer (APC). We performed a retrospective analysis of all patients who received mFOLFIRI (minus bolus 5FU and LV). All patients with metastatic disease who had failed at least one line of gemcitabine-based therapy prior to receiving mFOLFIRI were included in this study. Descriptive statistics were used to assess the continuous variables and adverse events (AEs), and Kaplan-Meier methods were used to calculate the median progression-free survival (PFS) and overall survival (OS). Forty patients were included in this analysis. Patients received 1-5 lines of prior therapy (25 % with more than 3 lines of prior therapy). The mean age at diagnosis was 60, and 98 % had ECOG of 1. The mean CA 19-9 at the start of therapy was 33,169 U/ml. The median PFS was 2.59 months [95 % confidence interval (CI) (1.90, 3.54)], and OS was 4.75 months [95 % CI (3.14, 8.98)]. The most common AEs included fatigue (98 %), neuropathy (83 %), anorexia (68 %), nausea (60 %) and constipation (55 %). Grade 3 toxicities included fatigue (13 %) and rash (3 %). There were no observed grade 4 toxicities. In this single-institution retrospective analysis, mFOLFIRI was found to be both tolerable and relatively effective in a heavily pretreated patient population with APC. Future prospective studies should consider evaluating the role of mFOLFIRI in refractory APC.