Towards an optimal treatment algorithm for metastatic pancreatic ductal adenocarcinoma (PDA)

Global lipid remodelling by hypoxia aggravates migratory potential in pancreatic cancer while maintaining plasma membrane homeostasis

Hypoxia plays an important role in pancreatic cancer progression. It drives various metabolic reprogramming in cells including that of lipids, which in turn, can modify the structure and function of cell membranes. Homeostatic adaptation of membranes is well-recognized, but how and if it is regulated in hypoxic pancreatic cancer and its relation to aggressive phenotype and metastasis remains elusive. Here we show hypoxia-induced extensive global lipid remodelling spanning changes in lipid classes, unsaturation levels, glyceryl backbone and acyl chain lengths. No major modulation of plasma membrane biophysical properties revealed a decoupling of lipidome modulation from membrane properties under hypoxia. This was supported by observing minor changes in the lipidome of plasma membranes under hypoxia. Further, hypoxia increased migration and invasion underpinned by reduced actin volume, cell cortical stiffness and facile tether dynamics. In conclusion, we demonstrate buffering of the lipidome alterations leading to a homeostatic membrane response. These findings will help to understand the hypoxic regulation of pancreatic membrane homeostasis and identify tangible theranostic avenues.

Sesquiterpene Lactones as Promising Candidates for Cancer Therapy: Focus on Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease which confers to patients a poor prognosis at short term. PDAC is the fourth leading cause of death among cancers in the Western world. The rate of new cases of pancreatic cancer (incidence) is 10 per 100,000 but present a 5-year survival of less than 10%, highlighting the poor prognosis of this pathology. Furthermore, 90% of advanced PDAC tumor present KRAS mutations impacting in several oncogenic signaling pathways, many of them associated with cell proliferation and tumor progression. Different combinations of chemotherapeutic agents have been tested over the years without an improvement of significance in its treatment. PDAC remains as one the more challenging biomedical topics thus far. The lack of a proper early diagnosis, the notable mortality statistics and the poor outcome with the available therapies urge the entire scientific community to find novel approaches against PDAC with real improvements in patients' survival and life quality. Natural compounds have played an important role in the process of discovery and development of new drugs. Among them, terpenoids, such as sesquiterpene lactones, stand out due to their biological activities and pharmacological potential as antitumor agents. In this review, we will describe the sesquiterpene lactones with in vitro and in vivo activity against pancreatic tumor cells. We will also discuss the mechanism of action of the compounds as well as the signaling pathways associated with their activity.

Long Non-Coding RNAs in Pancreatic Cancer: Biologic Functions, Mechanisms, and Clinical Significance

Despite tremendous efforts devoted to research in pancreatic cancer (PC), the mechanism underlying the tumorigenesis and progression of PC is still not completely clear. Additionally, ideal biomarkers and satisfactory therapeutic strategies for clinical application in PC are still lacking. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) might participate in the pathogenesis of diverse cancers, including PC. The abnormal expression of lncRNAs in PC is considered a vital factor during tumorigenesis that affects tumor cell proliferation, migration, invasion, apoptosis, angiogenesis, and drug resistance. With this review of relevant articles published in recent years, we aimed to summarize the biogenesis mechanism, classifications, and modes of action of lncRNAs and to review the functions and mechanisms of lncRNAs in PC. Additionally, the clinical significance of lncRNAs in PC was discussed. Finally, we pointed out the questions remaining from recent studies and anticipated that further investigations would address these gaps in knowledge in this field.

Liposomal Irinotecan: A Review in Metastatic Pancreatic Adenocarcinoma

Liposomal irinotecan (nal-IRI; Onivyde^®; also known as pegylated liposomal irinotecan) has been developed with the aim of maximising anti-tumour efficacy while minimising drug-related toxicities compared with the conventional (non-liposomal) formulation of this topoisomerase 1 inhibitor. In combination with 5-fluorouracil and leucovorin (5-FU/LV), nal-IRI is the first agent to be specifically approved for use in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) who have progressed following gemcitabine-based therapy. In the pivotal, phase III NAPOLI-1 trial, intravenous administration of nal-IRI + 5-FU/LV to gemcitabine-pretreated patients with mPDAC (as a second-line treatment in approximately two-thirds of cases) was associated with a significant ≈ 2-month median overall survival advantage compared with 5-FU/LV alone. Moreover, adding nal-IRI to 5-FU/LV extended survival with a manageable safety profile and without adversely affecting health-related quality of life, thereby producing significant and clinically meaningful gains in quality-adjusted survival relative to 5-FU/LV alone. Complementing the observed efficacy and safety of nal-IRI in NAPOLI-1 are an increasing number of real-world studies, which provide evidence of the effectiveness of this combination therapy in the treatment of mPDAC that has progressed following gemcitabine-based therapy in contemporary clinical practice in Europe, the USA and East Asia. Thus, nal-IRI, in combination with 5-FU/LV, is the first regimen specifically approved for use as a second- or subsequent-line therapy in gemcitabine-pretreated patients with mPDAC and, as such, represents a valuable treatment option in this setting.

ERRα promotes pancreatic cancer progression by enhancing the transcription of PAI1 and activating the MEK/ERK pathway

Estrogen-related receptor alpha (ERRα), an orphan nuclear receptor, was reported to be highly associated with the progression and tumorigenesis of several human malignancies. However, the biological role and underlying molecular mechanisms of ERRα in pancreatic cancer (PC) remain unknown. The present study demonstrated that ERRα was significantly overexpressed in PC tissues and cell lines. Its high expression was correlated with tumor size, distant metastasis, TNM stage, tumor differentiation and poor prognosis of PC. Subsequent functional assays showed that ERRα promoted PC cell proliferation, tumor growth, as well as migration and invasion via activating the epithelial-mesenchymal transition. In addition, knockdown of ERRα induced apoptosis and G0/G1 cell cycle arrest in PC cells. Plasminogen activator inhibitor 1 (PAI1) was identified by RNA sequencing, knockdown of which could suppress the cell proliferation, migration and invasion that promoted by ERRα overexpression. Further mechanistic investigation using chromatin immunoprecipitation and dual-luciferase reporter assays revealed that ERRα could bind to the PAI1 promoter region and transcriptionally enhance PAI1 expression. Moreover, our data indicated that ERRα played its oncogenic role in PC via activating the MEK/ERK pathway. Taken together, our study demonstrates that ERRα promotes PC progression by enhancing the transcription of PAI1 and activation of the MEK/ERK pathway, pointing to ERRα as a novel diagnostic and therapeutic target for PC.

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.

Real-world comparative effectiveness of nab-paclitaxel plus gemcitabine versus FOLFIRINOX in advanced pancreatic cancer: a systematic review

BACKGROUND

No clinical trial has directly compared nab-paclitaxel/gemcitabine (nab-P/G) with FOLFIRINOX (fluorouracil/leucovorin/oxaliplatin/irinotecan) in metastatic or advanced pancreatic cancer (mPC or aPC). We conducted a systematic review of real-world studies comparing these regimens in the first-line setting.

METHODS

Embase and MEDLINE databases through 22 January 2019, and Gastrointestinal Cancers Symposium 2019 abstracts were searched for real-world, retrospective studies comparing first-line nab-P/G versus FOLFIRINOX in mPC or aPC that met specific parameters. Studies with radiotherapy were excluded. Study quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

Of 818 records initially identified, 35 were duplicates and 749 did not meet the eligibility criteria, mostly because they were either not comparative (n = 356) or not first line (n = 245). The remaining 34 studies (21 mPC; 13 aPC) assessed >6915 patients who received nab-P/G or FOLFIRINOX. In the studies identified, the median overall survival (OS) reached 14.4 and 15.9 months with nab-P/G and FOLFIRINOX, respectively, and median progression-free survival reached 8.5 and 11.7 months, respectively. Safety data were reported in 14 studies (2205 patients), including 8 single-institutional studies. In most single-institutional studies that reported safety data, rates were higher with FOLFIRINOX versus nab-P/G for grade 3/4 neutropenia (five of six studies) and febrile neutropenia (all three studies), while rates of grade 3/4 peripheral neuropathy were higher with nab-P/G in four of seven studies.

CONCLUSIONS

Although FOLFIRINOX was associated with slightly longer median OS in more studies, the differences, when available, were not statistically significant. Therefore, a randomized, controlled trial is warranted. Toxicity profile differences represent key considerations for treatment decisions.

Long non-coding RNA LINC00346 promotes pancreatic cancer growth and gemcitabine resistance by sponging miR-188-3p to derepress BRD4 expression

BACKGROUND

Long non-coding RNA LINC00346 has been recently suggested as a prognostic marker in pancreatic cancer. However, its biological function in pancreatic cancer has not yet been determined. In this study, we attempted to ascertain the role of LINC00346 in regulating the aggressiveness of pancreatic cancer.

METHODS

The effects of overexpression and knockdown of LINC00346 on the proliferation, cell cycle progression, apoptosis, and gemcitabine resistance were investigated. Bioinformatic analysis, luciferase reporter assay, and RNA immunoprecipitation assay were performed to search for potential microRNAs (miRs) that can interact with LINC00346.

RESULTS

Overexpression of LINC00346 significantly enhanced the proliferation, colony formation, and tumorigenesis of pancreatic cancer cells. Conversely, knockdown of LINC00346 suppressed pancreatic cancer cell proliferation and caused a cell-cycle arrest at the G2/M-phase. Depletion of LINC00346 also enhanced gemcitabine sensitivity in pancreatic cancer cells both in vitro and in vivo. Mechanistic investigation revealed that LINC00346 acted as a sponge for miR-188-3p and blocked the repression of BRD4 by miR-188-3p in pancreatic cancer cells. Clinical evidence indicated a negative correlation between LINC00346 and miR-188-3p in pancreatic cancer specimens. Rescue experiments showed that LINC00346 attenuated the growth-suppressing and chemosensitizing effects of miR-188-3p on pancreatic cancer cells. In addition, silencing of BRD4 significantly inhibited LINC00346-induced pancreatic cancer cell proliferation and colony formation.

CONCLUSIONS

LINC00346 shows the ability to promote pancreatic cancer growth and gemcitabine resistance, which is in part mediated by antagonization of miR-188-3p and induction of BRD4. Targeting LINC00346 may improve gemcitabine-based therapeutic efficacy.