Role of oncogenic KRAS in the diagnosis, prognosis and treatment of pancreatic cancer

Albumin conjugation promotes arsenic trioxide transport through alkaline phosphatase-associated transcytosis in MUC4 wildtype pancreatic cancer cells

Pancreatic cancer (PC) has a poor prognosis due to chemotherapy resistance and unfavorable drug transportation. Albumin conjugates are commonly used as drug carriers to overcome these obstacles. However, membrane-bound glycoprotein mucin 4 (MUC4) has emerged as a promising biomarker among the genetic mutations affecting albumin conjugates therapeutic window. Human serum albumin-conjugated arsenic trioxide (HSA-ATO) has shown potential in treating solid tumors but is limited in PC therapy due to unclear targets and mechanisms. This study investigated the transport mechanisms and therapeutic efficacy of HSA-ATO in PC cells with different MUC4 mutation statuses. Results revealed improved penetration of ATO into PC tumors through conjugated with HSA. However, MUC4 mutation significantly affected treatment sensitivity and HSA-ATO uptake both in vitro and in vivo. Mutant MUC4 cells exhibited over ten times higher IC50 for HSA-ATO and approximately half the uptake compared to wildtype cells. Further research demonstrated that ALPL activation by HSA-ATO enhanced transcytosis in wildtype MUC4 PC cells but not in mutant MUC4 cells, leading to impaired uptake and weaker antitumor effects. Reprogramming the transport process holds potential for enhancing albumin conjugate efficacy in PC patients with different MUC4 mutation statuses, paving the way for stratified treatment using these delivery vehicles.

Extracellular vesicles associated microRNAs: Their biology and clinical significance as biomarkers in gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, esophageal, pancreatic, and liver, are associated with high mortality and morbidity rates worldwide. One of the underlying reasons for the poor survival outcomes in patients with these malignancies is late disease detection, typically when the tumor has already advanced and potentially spread to distant organs. Increasing evidence indicates that earlier detection of these cancers is associated with improved survival outcomes and, in some cases, allows curative treatments. Consequently, there is a growing interest in the development of molecular biomarkers that offer promise for screening, diagnosis, treatment selection, response assessment, and predicting the prognosis of these cancers. Extracellular vesicles (EVs) are membranous vesicles released from cells containing a repertoire of biological molecules, including nucleic acids, proteins, lipids, and carbohydrates. MicroRNAs (miRNAs) are the most extensively studied non-coding RNAs, and the deregulation of miRNA levels is a feature of cancer cells. EVs miRNAs can serve as messengers for facilitating interactions between tumor cells and the cellular milieu, including immune cells, endothelial cells, and other tumor cells. Furthermore, recent years have witnessed considerable technological advances that have permitted in-depth sequence profiling of these small non-coding RNAs within EVs for their development as promising cancer biomarkers -particularly non-invasive, liquid biopsy markers in various cancers, including GI cancers. Herein, we summarize and discuss the roles of EV-associated miRNAs as they play a seminal role in GI cancer progression, as well as their promising translational and clinical potential as cancer biomarkers as we usher into the area of precision oncology.

Integrative analysis of spatial and single-cell transcriptome data from human pancreatic cancer reveals an intermediate cancer cell population associated with poor prognosis

BACKGROUND

Recent studies using single-cell transcriptomic analysis have reported several distinct clusters of neoplastic epithelial cells and cancer-associated fibroblasts in the pancreatic cancer tumor microenvironment. However, their molecular characteristics and biological significance have not been clearly elucidated due to intra- and inter-tumoral heterogeneity.

METHODS

We performed single-cell RNA sequencing using enriched non-immune cell populations from 17 pancreatic tumor tissues (16 pancreatic cancer and one high-grade dysplasia) and generated paired spatial transcriptomic data from seven patient samples.

RESULTS

We identified five distinct functional subclusters of pancreatic cancer cells and six distinct cancer-associated fibroblast subclusters. We deeply profiled their characteristics, and we found that these subclusters successfully deconvoluted most of the features suggested in bulk transcriptome analysis of pancreatic cancer. Among those subclusters, we identified a novel cancer cell subcluster, Ep_VGLL1, showing intermediate characteristics between the extremities of basal-like and classical dichotomy, despite its prognostic value. Molecular features of Ep_VGLL1 suggest its transitional properties between basal-like and classical subtypes, which is supported by spatial transcriptomic data.

CONCLUSIONS

This integrative analysis not only provides a comprehensive landscape of pancreatic cancer and fibroblast population, but also suggests a novel insight to the dynamic states of pancreatic cancer cells and unveils potential therapeutic targets.

Short-term serial circulating tumor DNA assessment predicts therapeutic efficacy for patients with advanced pancreatic cancer

PURPOSE

We investigated the potential clinical utility of short-term serial KRAS-mutated circulating cell-free tumor DNA (ctDNA) assessment for predicting therapeutic response in patients undergoing first-line chemotherapy for advanced pancreatic cancer.

METHODS

We collected 144 blood samples from 18 patients with locally advanced or metastatic cancer that were undergoing initial first-line chemotherapy of gemcitabine plus nab-paclitaxel (GEM plus nab-PTX). Analysis of KRAS-mutated ctDNA was quantified by digital droplet polymerase chain reaction (ddPCR) as mutant allele frequency (MAF). This study investigated pretreatment KRAS-mutated ctDNA status and ctDNA kinetics every few days (days 1, 3, 5 and 7) after initiation of chemotherapy and their potential as predictive indicators.

RESULTS

Of the 18 enrolled patients, an increase in KRAS-mutated ctDNA MAF values from day 0-7 after initiation of chemotherapy was significantly associated with disease progression (P < 0.001). Meanwhile, positive pretreatment ctDNA status (MAF ≥ 0.02%) (P = 0.585) and carbohydrate antigen 19-9 (CA19-9) values above the median (P = 0.266) were not associated with disease progression. In univariate analysis, this short-term increase in ctDNA MAF values (day 0-7) was found to be associated with significantly shorter progression free survival (PFS) (hazard ration [HR], 24.234; range, (2.761-212.686); P = 0.0002).

CONCLUSION

This short-term ctDNA kinetics assessment may provide predictive information to reflect real-time therapeutic response and lead to effective refinement of regimen in patients with advanced pancreatic cancer undergoing systemic chemotherapy.

Design, Synthesis, and Biological Evaluation of Potent and Selective PROTAC Degraders of Oncogenic KRASG12D

KRASG12D, the most frequent KRAS oncogenic mutation, is a promising target for cancer therapy. Herein, we report the design, synthesis, and biological evaluation of a series of KRASG12D PROTACs by connecting the analogues of MRTX1133 and the VHL ligand. Structural modifications of the linker moiety and KRAS inhibitor part suggested a critical role of membrane permeability in the degradation activity of the KRASG12D PROTACs. Mechanism studies with the representative compound 8o demonstrated that the potent, rapid, and selective degradation of KRASG12D induced by 8o was via a VHL- and proteasome-dependent manner. This compound selectively and potently suppressed the growth of multiple KRASG12D mutant cancer cells, displayed favorable pharmacokinetic and pharmacodynamic properties in mice, and showed significant antitumor efficacy in the AsPC-1 xenograft mouse model. Further optimization of 8o appears to be promising for the development of a new chemotherapy for KRASG12D-driven cancers as the complementary therapeutic strategy to KRAS inhibition.

CHST12: a potential prognostic biomarker related to the immunotherapy response in pancreatic adenocarcinoma

Background

Pancreatic adenocarcinoma (PAAD) is characterized by lower immunogenicity with a poor response rate to immune checkpoint inhibitors (ICIs) and exhibits the poorest prognosis of all solid tumors, which results in the highest tumor-related mortality among malignancies. However, the underlying mechanisms are poorly understood. In addition, diverse carbohydrate sulfotransferases (CHSTs), which are involved in the sulfation process of these structures, play an important role in the metastatic spread of tumor cells. Aberrant glycosylation is beginning to emerge as an influencing factor in tumor immunity and immunotherapy. Therefore, it might serve as a biomarker of the immunotherapeutic response in tumors. The purpose of the study was to evaluate the role of CHST12 in PAAD prognosis and its relevance to the immunotherapeutic response.

Methods

A comprehensive investigation of the interactions between CHST12 expression and the immune microenvironment as well as the clinical significance of CHST12 in PAAD was conducted. Data derived from the Cancer Genome Atlas (TCGA) database were analyzed using univariate and multivariate approaches, the Tumor Immune Estimation Resource (TIMER), and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms. Publicly available datasets were analyzed in this study. These data can be found on websites such as http://www.xiantao.love and https://www.proteinatlas.org. An assessment of the predictive value of CHST12 for PAAD prognosis was conducted using univariate and multivariate Cox regression analysis, Kaplan-Meier analysis, and nomograms. The TIMER algorithm calculates the proportions of six types of immune cells. The TIDE algorithm was used to indicate the characteristics of tumors that respond to ICI therapy.

Results

The mRNA and protein levels of CHST12 showed the opposite trend. CHST12 mRNA expression was significantly upregulated in PAAD. According to Cox regression analysis, CHST12 RNA expression acts as a protective factor for overall survival [hazard ratio (HR), 0.617, P < 0.04]. Functional annotation indicated that CHST12-associated differentially expressed genes (DEGs) were related to the signaling activity of receptor tyrosine kinases and the regulation of ubiquitin-protein transferase. These are usually involved in tumor development and may be related to the treatment responses of immune checkpoint inhibitors (ICIs). There was significantly higher CHST12 mRNA expression in PAAD samples than in non-malignant samples.

Conclusions

In PAAD, elevated CHST12 mRNA expression might regulate immune cell infiltration into the tumor microenvironment (TME) and may predict clinical outcomes.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

Background

The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB).

Objectives

We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival.

Design

In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed.

Methods

The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC).

Results

A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation.

Conclusion

KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

Exploring KRAS-mutant pancreatic ductal adenocarcinoma: a model validation study

Introduction

Pancreatic ductal adenocarcinoma (PDAC) has the highest mortality rate among all solid tumors. Tumorigenesis is promoted by the oncogene KRAS, and KRAS mutations are prevalent in patients with PDAC. Therefore, a comprehensive understanding of the interactions between KRAS mutations and PDAC may expediate the development of therapeutic strategies for reversing the progression of malignant tumors. Our study aims at establishing and validating a prediction model of KRAS mutations in patients with PDAC based on survival analysis and mRNA expression.

Methods

A total of 184 and 412 patients with PDAC from The Cancer Genome Atlas (TCGA) database and the International Cancer Genome Consortium (ICGC), respectively, were included in the study.

Results

After tumor mutation profile and copy number variation (CNV) analyses, we established and validated a prediction model of KRAS mutations, based on survival analysis and mRNA expression, that contained seven genes: CSTF2, FAF2, KIF20B, AKR1A1, APOM, KRT6C, and CD70. We confirmed that the model has a good predictive ability for the prognosis of overall survival (OS) in patients with KRAS-mutated PDAC. Then, we analyzed differential biological pathways, especially the ferroptosis pathway, through principal component analysis, pathway enrichment analysis, Gene Ontology (GO) enrichment analysis, and gene set enrichment analysis (GSEA), with which patients were classified into low- or high-risk groups. Pathway enrichment results revealed enrichment in the cytokine-cytokine receptor interaction, metabolism of xenobiotics by cytochrome P450, and viral protein interaction with cytokine and cytokine receptor pathways. Most of the enriched pathways are metabolic pathways predominantly enriched by downregulated genes, suggesting numerous downregulated metabolic pathways in the high-risk group. Subsequent tumor immune infiltration analysis indicated that neutrophil infiltration, resting CD4 memory T cells, and resting natural killer (NK) cells correlated with the risk score. After verifying that the seven gene expression levels in different KRAS-mutated pancreatic cancer cell lines were similar to that in the model, we screened potential drugs related to the risk score.

Discussion

This study established, analyzed, and validated a model for predicting the prognosis of PDAC based on risk stratification according to KRAS mutations, and identified differential pathways and highly effective drugs.

Advancing cancer treatment: in vivo delivery of therapeutic small noncoding RNAs

In recent years, small non-coding RNAs (ncRNAs) have emerged as a new player in the realm of cancer therapeutics. Their unique capacity to directly modulate genetic networks and target oncogenes positions them as valuable complements to existing small-molecule drugs. Concurrently, the advancement of small ncRNA-based therapeutics has rekindled the pursuit of efficacious in vivo delivery strategies. In this review, we provide an overview of the most current clinical and preclinical studies in the field of small ncRNA-based cancer therapeutics. Furthermore, we shed light on the pivotal challenges hindering the successful translation of these promising therapies into clinical practice, with a specific focus on delivery methods, aiming to stimulate innovative approaches to address this foundational aspect of cancer treatment.

Evidence-Based Dampness-Heat ZHENG (Syndrome) in Cancer: Current Progress toward Establishing Relevant Animal Model with Pancreatic Tumor

Cancer is one of the deadliest diseases affecting the health of human beings. With limited therapeutic options available, complementary and alternative medicine has been widely adopted in cancer management and is increasingly becoming accepted by both patients and healthcare workers alike. Chinese medicine characterized by its unique diagnostic and treatment system is the most widely applied complementary and alternative medicine. It emphasizes symptoms and ZHENG (syndrome)-based treatment combined with contemporary disease diagnosis and further stratifies patients into individualized medicine subgroups. As a representative cancer with the highest degree of malignancy, pancreatic cancer is traditionally classified into the "amassment and accumulation". Emerging perspectives define the core pathogenesis of pancreatic cancer as "dampness-heat" and the respective treatment "clearing heat and resolving dampness" has been demonstrated to prolong survival in pancreatic cancer patients, as has been observed in many other cancers. This clinical advantage encourages an exploration of the essence of dampness-heat ZHENG (DHZ) in cancer and investigation into underlying mechanisms of action of herbal formulations against dampness-heat. However, at present, there is a lack of understanding of the molecular characteristics of DHZ in cancer and no standardized and widely accepted animal model to study this core syndrome in vivo. The shortage of animal models limits the ability to uncover the antitumor mechanisms of herbal medicines and to assess the safety profile of the natural products derived from them. This review summarizes the current research on DHZ in cancer in terms of the clinical aspects, molecular landscape, and animal models. This study aims to provide comprehensive insight that can be used for the establishment of a future standardized ZHENG-based cancer animal model.

Gastrointestinal Malignancy: Genetic Implications to Clinical Applications

Advances in molecular genetics have revolutionized our understanding of the pathogenesis, progression, and therapeutic options for treating gastrointestinal (GI) cancers. This chapter provides a comprehensive overview of the molecular landscape of GI cancers, focusing on key genetic alterations implicated in tumorigenesis across various anatomical sites including GIST, colon and rectum, and pancreas. Emphasis is placed on critical oncogenic pathways, such as mutations in tumor suppressor genes, oncogenes, chromosomal instability, microsatellite instability, and epigenetic modifications. The role of molecular biomarkers in predicting prognosis, guiding treatment decisions, and monitoring therapeutic response is discussed, highlighting the integration of genomic profiling into clinical practice. Finally, we address the evolving landscape of precision oncology in GI cancers, considering targeted therapies and immunotherapies.

Oligomeric organization of membrane proteins from native membranes at nanoscale spatial and single-molecule resolution

The oligomeric organization of membrane proteins in native cell membranes is a critical regulator of their function. High-resolution quantitative measurements of oligomeric assemblies and how they change under different conditions are indispensable to understanding membrane protein biology. We report Native-nanoBleach, a total internal reflection fluorescence microscopy-based single-molecule photobleaching step analysis technique to determine the oligomeric distribution of membrane proteins directly from native membranes at an effective spatial resolution of ~10 nm. We achieved this by capturing target membrane proteins in native nanodiscs with their proximal native membrane environment using amphipathic copolymers. We applied Native-nanoBleach to quantify the oligomerization status of structurally and functionally diverse membrane proteins, including a receptor tyrosine kinase (TrkA) and a small GTPase (KRas) under growth-factor binding and oncogenic mutations, respectively. Our data suggest that Native-nanoBleach provides a sensitive, single-molecule platform to quantify membrane protein oligomeric distributions in native membranes under physiologically and clinically relevant conditions.

High-resolution and quantitative spatial analysis reveal intra-ductal phenotypic and functional diversification in pancreatic cancer

A 'classical' and a 'basal-like' subtype of pancreatic cancer have been reported, with differential expression of GATA6 and different dosages of mutant KRAS. We established in situ detection of KRAS point mutations and mRNA panels for the consensus subtypes aiming to project these findings to paraffin-embedded clinical tumour samples for spatial quantitative analysis. We unveiled that, next to inter-patient and intra-patient inter-ductal heterogeneity, intraductal spatial phenotypes exist with anti-correlating expression levels of GATA6 and KRASG12D . The basal-like mRNA panel better captured the basal-like cell states than widely used protein markers. The panels corroborated the co-existence of the classical and basal-like cell states in a single tumour duct with functional diversification, i.e. proliferation and epithelial-to-mesenchymal transition respectively. Mutant KRASG12D detection ascertained an epithelial origin of vimentin-positive cells in the tumour. Uneven spatial distribution of cancer-associated fibroblasts could recreate similar intra-organoid diversification. This extensive heterogeneity with functional cooperation of plastic tumour cells poses extra challenges to therapeutic approaches. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Acquired and intrinsic gemcitabine resistance in pancreatic cancer therapy: Environmental factors, molecular profile and drug/nanotherapeutic approaches

A high number of cancer patients around the world rely on gemcitabine (GEM) for chemotherapy. During local metastasis of cancers, surgery is beneficial for therapy, but dissemination in distant organs leads to using chemotherapy alone or in combination with surgery to prevent cancer recurrence. Therapy failure can be observed as a result of GEM resistance, threatening life of pancreatic cancer (PC) patients. The mortality and morbidity of PC in contrast to other tumors are increasing. GEM chemotherapy is widely utilized for PC suppression, but resistance has encountered its therapeutic impacts. The purpose of current review is to bring a broad concept about role of biological mechanisms and pathways in the development of GEM resistance in PC and then, therapeutic strategies based on using drugs or nanostructures for overcoming chemoresistance. Dysregulation of the epigenetic factors especially non-coding RNA transcripts can cause development of GEM resistance in PC and miRNA transfection or using genetic tools such as siRNA for modulating expression level of these factors for changing GEM resistance are suggested. The overexpression of anti-apoptotic proteins and survival genes can contribute to GEM resistance in PC. Moreover, supportive autophagy inhibits apoptosis and stimulates GEM resistance in PC cells. Increase in metabolism, glycolysis induction and epithelial-mesenchymal transition (EMT) stimulation are considered as other factors participating in GEM resistance in PC. Drugs can suppress tumorigenesis in PC and inhibit survival factors and pathways in increasing GEM sensitivity in PC. More importantly, nanoparticles can increase pharmacokinetic profile of GEM and promote its blood circulation and accumulation in cancer site. Nanoparticles mediate delivery of GEM with genes and drugs to suppress tumorigenesis in PC and increase drug sensitivity. The basic research displays significant connection among dysregulated pathways and GEM resistance, but the lack of clinical application is a drawback that can be responded in future.

Tissue-adjusted pathway analysis of cancer (TPAC): A novel approach for quantifying tumor-specific gene set dysregulation relative to normal tissue

We describe a novel single sample gene set testing method for cancer transcriptomics data named tissue-adjusted pathway analysis of cancer (TPAC). The TPAC method leverages information about the normal tissue-specificity of human genes to compute a robust multivariate distance score that quantifies gene set dysregulation in each profiled tumor. Because the null distribution of the TPAC scores has an accurate gamma approximation, both population and sample-level inference is supported. As we demonstrate through an analysis of gene expression data for 21 solid human cancers from The Cancer Genome Atlas (TCGA) and associated normal tissue expression data from the Human Protein Atlas (HPA), TPAC gene set scores are more strongly associated with patient prognosis than the scores generated by existing single sample gene set testing methods.

The ethyl acetate extract of Vernonia amygdalina leaf ameliorates gemcitabine effect against migration and invasion of PANC-1 cells via down-regulation the VEGF, COX2, and RAS/MEK pathways

Individuals diagnosed with cancer often turn to the use of herbal remedies with the intention of treating and ameliorating the condition, impeding the progression of metastasis, enhancing immune function, mitigating stress, and inducing relaxation. Recently, medicinal plants were combined with conventional chemotherapy to decrease the side effects and increase the effectiveness of chemotherapy. This study showed the effectiveness of gemcitabine (Gem) was significantly increased after being used together with ethyl acetate extract obtained from Vernonia amygdalina (Eav) leaves. The combination doses of Eav and Gem were determined based on cytotoxic activity using the MTT assay method. The anticancer effect of this combination was identified by several parameters including the apoptosis effect, anti-migration, and anti-invasion activities of PANC-1 cells. Furthermore, this effect was explained via protein expression evaluation using immunohistochemical and flow cytometry. The Eav has a better Inhibitory Concentration 50 (IC50) than Gem of 21.19 ± 0.64 µg/mL and 164.78 ± 1.40 µg/mL. The combination of Eav and Gem at IC50 (1:1) has the strongest activity than Eav and Gem alone at 500.00 µg/mL. The anti-cancer effect of this combination showed significantly increased levels of apoptosis, particularly in the early phase of 17.46 ± 0.35 % (p < 0.0001) than Eav and Gem alone of 7.76 ± 0.25 % and 7.06 ± 0.20 %. A similar impact was evaluated in the migration and invasion of PANC-1 cells after the combination treatment. The % relative migration and cell invasion were significantly decreased compared to the control group and Eav or Gem alone by 21.49 ± 0.96 % and 125.25 ± 5.25 cells, respectively (p < 0.0001). This study found that signature molecules of VEGF, COX2, RAS, and MEK were down-regulated after treatment. Our study suggested that the Eav ameliorates the Gem effect against PANC-1 cells through apoptosis, migration, and invasion influence via RAS/MEK pathways.

Expanding the ubiquitin code in pancreatic cancer

The ubiquitin-proteasome system (UPS) is a fundamental regulatory mechanism in cells, vital for maintaining cellular homeostasis, compiling signaling transduction, and determining cell fates. These biological processes require the coordinated signal cascades of UPS members, including ubiquitin ligases, ubiquitin-conjugating enzymes, deubiquitinases, and proteasomes, to ubiquitination and de-ubiquitination on substrates. Recent studies indicate that ubiquitination code rewriting is particularly prominent in pancreatic cancer. High frequency mutation or aberrant hyperexpression of UPS members dysregulates ferroptosis, tumor microenvironment, and metabolic rewiring processes and contribute to tumor growth, metastasis, immune evasion, and acquired drug resistance. We conduct an in-depth overview of ubiquitination process in pancreatic cancer, highlighting the role of ubiquitin code in tumor-promoting and tumor-suppressor pathways. Furthermore, we review current UPS modulators and analyze the potential of UPS modulators as cancer therapy.

Next-generation therapies for pancreatic cancer

INTRODUCTION

Pancreas ductal adenocarcinoma (PDAC) is a frequently lethal malignancy that poses unique therapeutic challenges. The current mainstay of therapy for metastatic PDAC (mPDAC) is cytotoxic chemotherapy. NALIRIFOX (liposomal irinotecan, fluorouracil, leucovorin, oxaliplatin) is an emerging standard of care in the metastatic setting. An evolving understanding of PDAC pathogenesis is driving a shift toward targeted therapy. Olaparib, a poly-ADP-ribose polymerase (PARP) inhibitor, has regulatory approval for maintenance therapy in BRCA-mutated mPDAC along with other targeted agents receiving disease-agnostic approvals including for PDAC with rare fusions and mismatch repair deficiency. Ongoing research continues to identify and evaluate an expanding array of targeted therapies for PDAC.

AREAS COVERED

This review provides a brief overview of standard therapies for PDAC and an emphasis on current and emerging targeted therapies.

EXPERT OPINION

There is notable potential for targeted therapies for KRAS-mutated PDAC with opportunity for meaningful benefit for a sizable portion of patients with this disease. Further, emerging approaches are focused on novel immune, tumor microenvironment, and synthetic lethality strategies.

Ultrasensitive and High-Resolution Protein Spatially Decoding Framework for Tumor Extracellular Vesicles

Proteins localized on the surface or within the lumen of tumor-derived extracellular vesicles (EVs) play distinct roles in cancer progression. However, quantifying both populations of proteins within EVs has been hampered due to the limited sensitivity of the existing protein detection methods and inefficient EV isolation techniques. In this study, the eSimoa framework, an innovative approach enabling spatial decoding of EV protein biomarkers with unmatched sensitivity and specificity is presented. Using the luminal eSimoa pipeline, the absolute concentration of luminal RAS or KRASG12D proteins is released and measured, uncovering their prevalence in pancreatic tumor-derived EVs. The pulldown eSimoa pipeline measured absolute protein concentrations from low-abundance EV subpopulations. The eSimoa assays detected EVs in both PBS and plasma samples, confirming their applicability across diverse clinical sample types. Overall, the eSimoa framework offers a valuable tool to (1) detect EVs at concentrations as low as 105 EV mL-1 in plasma, (2) quantify absolute EV protein concentrations as low as fM, and (3) decode the spatial distribution of EV proteins. This study highlights the potential of eSimoa in identifying disease-specific EV protein biomarkers in clinical samples with minimal pre-purification, thereby driving advancements in clinical translation.

In silico Exploration of a Novel ICMT Inhibitor with More Solubility than Cysmethynil against Membrane Localization of KRAS Mutant in Colorectal Cancer

BACKGROUND

ICMT (isoprenylcysteine carboxyl methyltransferase) is an enzyme that plays a key role in the post-translational modification of the K-Ras protein. The carboxyl methylation of this protein by ICMT is important for its proper localization and function. Cysmethynil (2-[5-(3-methylphenyl)-l-octyl-lH-indolo-3-yl] acetamide) causes K-Ras mislocalization and interrupts pathways that control cancer cell growth and division through inhibition of ICMT, but its poor water solubility makes it difficult and impractical for clinical use. This indicates that relatively high amounts of cysmethynil would be required to achieve an effective dose, which could result in significant adverse effects in patients.

OBJECTIVE

The general objective of this work was to find virtually new compounds that present high solubility in water and are similar to the pharmacological activity of cysmethynil.

MATERIALS AND METHODS

Pharmacophore modeling, pharmacophore-based virtual screening, prediction of ADMET properties (absorption, distribution, metabolism, excretion, and toxicity), and water solubility were performed to recover a water-soluble molecule that shares the same chemical characteristics as cysmethynil using Discovery Studio v16.1.0 (DS16.1), SwissADME server, and pkCSM server.

RESULTS

In this study, ten pharmacophore model hypotheses were generated by exploiting the characteristics of cysmethynil. The pharmacophore model validated by the set test method was used to screen the "Elite Library®" and "Synergy Library" databases of Asinex. Only 1533 compounds corresponding to all the characteristics of the pharmacophore were retained. Then, the aqueous solubility in water at 25°C of these 1533 compounds was predicted by the Cheng and Merz model. Among these 1533 compounds, two had the optimal water solubility. Finally, the ADMET properties and Log S water solubility by three models (ESOL, Ali, and SILICOS-IT) of the two compounds and cysmethynil were compared, resulting in compound 2 as a potential inhibitor of ICMT.

CONCLUSION

According to the results obtained, the identified compound presented a high solubility in water and could be similar to the pharmacological activity of cysmethynil.

Digging into the NGS Information from a Large-Scale South European Population with Metastatic/Unresectable Pancreatic Ductal Adenocarcinoma: A Real-World Genomic Depiction

Despite ongoing oncological advances, pancreatic ductal adenocarcinoma (PDAC) continues to have an extremely poor prognosis with limited targeted and immunotherapeutic options. Its genomic background has not been fully characterized yet in large-scale populations all over the world. Methods: Replicating a recent study from China, we collected tissue samples from consecutive Greek patients with pathologically-confirmed metastatic/unresectable PDAC and retrospectively investigated their genomic landscape using next generation sequencing (NGS). Findings: From a cohort of 409 patients, NGS analysis was successfully achieved in 400 cases (56.50% males, median age: 61.8 years). Consistent with a previous study, KRAS was the most frequently mutated gene in 81.50% of tested samples, followed by TP53 (50.75%), CDKN2 (8%), and SMAD4 (7.50%). BRCA1/2 variants with on-label indications were detected in 2%, and 87.50% carried a variant associated with off-label treatment (KRAS, ERBB2, STK11, or HRR-genes), while 3.5% of the alterations had unknown/preliminary-studied actionability (TP53/CDKN2A). Most of HRR-alterations were in intermediate- and low-risk genes (CHEK2, RAD50, RAD51, ATM, FANCA, FANCL, FANCC, BAP1), with controversial actionability: 8% harbored a somatic non-BRCA1/2 alteration, 6 cases had a high-risk alteration (PALB2, RAD51C), and one co-presented a PALB2/BRCA2 alteration. Elevated LOH was associated with HRR-mutated status and TP53 mutations while lowered LOH was associated with KRAS alterations. Including TMB/MSI data, the potential benefit from an NGS-oriented treatment was increased from 1.91% to 13.74% (high-MSI: 0.3%, TMB > 10 muts/MB: 12.78%). TMB was slightly increased in females (4.75 vs. 4.46 muts/MB) and in individuals with age > 60 (4.77 vs. 4.40 muts/MB). About 28.41% showed PD-L1 > 1% either in tumor or immune cells, 15.75% expressed PD-L1 ≥ 10%, and only 1.18% had PD-L1 ≥ 50%. This is the largest depiction of real-world genomic characteristics of European patients with PDAC, which offers some useful clinical and research insights.

Acceleration of high-quality Raman imaging via a locality enhanced transformer network

Raman imaging (RI) is an outstanding technique that enables molecular-level medical diagnostics and therapy assessment by providing characteristic fingerprint and morphological information about molecules. However, obtaining high-quality Raman images generally requires a long acquisition time, up to hours, which is prohibitive for RI applications of timely cytopathology and histopathology analyses. To address this issue, image super-resolution (SR) based on deep learning, including convolutional neural networks and transformers, has been widely recognized as an effective solution to reduce the time required for achieving high-quality RI. In this study, a locality enhanced transformer network (LETNet) is proposed to perform Raman image SR. Specifically, the general architecture of the transformer is adopted with the replacement of self-attention by convolution to generate high-fidelity and detailed SR images. Additionally, the convolution in the LETNet is further optimized by utilizing depth-wise convolution to improve the computational efficiency of the model. Experiments on hyperspectral Raman images of breast cancer cells and Raman images of a few channels of brain tumor tissues demonstrate that the LETNet achieves superior 2×, 4×, and 8× SR with fewer parameters compared with other SR methods. Consequently, high-quality Raman images can be obtained with a significant reduction in time, ranging from 4 to 64 times. Overall, the proposed method provides a novel, efficient, and reliable solution to expedite high-quality RI and promote its application in real-time diagnosis and therapy.

The suppressive efficacy of THZ1 depends on KRAS mutation subtype and is associated with super-enhancer activity and the PI3K/AKT/mTOR signalling in pancreatic ductal adenocarcinoma: A hypothesis-generating study

BACKGROUND

Inhibition of CDK7, a potent transcription regulator, may bring new hope for treating pancreatic ductal adenocarcinoma (PDAC), which is featured by large genetic heterogeneity and abundant KRAS mutations. This investigation aimed at exploring the discrepant efficacies of THZ1, a small-molecule covalent CDK7 inhibitor, on PDACs with different KRAS mutations and the underlying mechanisms.

METHODS

Associations of CDK7 expression with survival by KRAS mutations were first assessed. Effects of THZ1 on PDAC by different KRAS mutations were then investigated in vitro and in vivo. Moreover, the effects of THZ1 on gene transcription and phosphorylation of RNA polymerase II (RNAPOLII) in different KRAS mutant PDACs were assessed, and the effect of THZ1 on super-enhancer activity was evaluated using chromatin immunoprecipitation sequencing. Lastly, the effects of THZ1 on the binding of H3K27ac to PIK3CA and on the PI3K/AKT/mTOR signalling were analysed.

RESULTS

High CDK7 expression was significantly linked to worse survival within PDAC patients carrying KRAS-G12V mutation but not in those with KRAS-G12D mutation. The apoptosis-inducing effect of THZ1 was markedly stronger in KRAS-G12V PDAC than KRAS-G12D cancer. THZ1 significantly inhibited the growth of xenograft tumour with KRAS-G12V mutation, and the inhibition was markedly stronger than for KRAS-G12D tumour. In mini-cell-derived xenograft (CDX) models, THZ1 significantly suppressed KRAS-G12V PDAC but not KRAS-G12D cancer. THZ1 significantly suppressed the phosphorylation of RNAPOLII, and this effect was stronger in KRAS-G12V PDAC (especially at ser5). KRAS-G12V PDAC had more H3K27ac-binding super-enhancers, and the inhibition of THZ1 on super-enhancer activity was also stronger in KRAS-G12V PDAC. Furthermore, THZ1 significantly weakened the binding of H3K27ac to PIK3CA in KRAS-G12V PDAC. THZ1 significantly suppressed the PI3K/AKT/mTOR pathway and its downstream markers, and this effect was stronger in KRAS-G12V cells.

CONCLUSIONS

In this hypothesis-generating study, THZ1 might selectively inhibit certain PDACs with KRAS-G12V mutation more potently compared with some other PDACs with KRAS-G12D mutation, which might be associated with its effect on super-enhancer activity and the PI3K/AKT/mTOR signalling. Our findings might offer novel key clues for the precise management of PDAC and important evidence for future targeted trial design.

HIGHLIGHTS

THZ1 had a stronger effect on PDAC-bearing KRAS-G12V mutation than G12D mutation. Suppressive effect of THZ1 on phosphorylation of RNAPOLII was stronger in KRAS-G12V than KRAS-G12D PDAC. Inhibition of THZ1 on super-enhancer activity and H3K27ac binding to PIK3CA was stronger in KRAS-G12V PDAC. Suppressive effect of THZ1 on PI3K/AKT/mTOR pathway was stronger in KRAS-G12V PDAC.

Pancreatic Ubap2 deletion regulates glucose tolerance, inflammation, and protection from cerulein-induced pancreatitis

Ubiquitin-binding associated protein 2 (UBAP2) is reported to promote macropinocytosis and pancreatic adenocarcinoma (PDAC) growth, however, its role in normal pancreatic function remains unknown. We addressed this knowledge gap by generating UBAP2 knockout (U2KO) mice under a pancreas-specific Cre recombinase (Pdx1-Cre). Pancreatic architecture remained intact in U2KO animals, but they demonstrated slight glucose intolerance compared to controls. Upon cerulein challenge to induce pancreatitis, U2KO animals had reduced levels of several pancreatitis-relevant cytokines, amylase and lipase in the serum, reduced tissue damage, and lessened neutrophil infiltration into the pancreatic tissue. Mechanistically, cerulein-challenged U2KO animals revealed reduced NF-κB activation compared to controls. In vitro promoter binding studies confirmed the reduction of NF-κB binding to its target molecules supporting UBAP2 as a new regulator of inflammation in pancreatitis and may be exploited as a therapeutic target in future to inhibit pancreatitis.

Papillary renal neoplasm with reverse polarity: a clinicopathologic study of 43 cases with a focus on the expression of KRAS signaling pathway downstream effectors

Papillary renal neoplasm with reverse polarity (PRNRP) is a renal tumor with frequent KRAS mutations. In this study, we aimed to report the clinical, histological, and immunohistochemical characteristics of PRNRP and the protein expression of various KRAS signaling pathway downstream effectors in PRNRP. PRNRP samples from patients who underwent surgical resection at Seoul National University Hospital over an 11-year period (January 2011 to December 2021) were analyzed. We identified 43 PRNRPs, defined as papillary renal tumors with a thin papillary architecture, eosinophilic finely granular cytoplasm, and apical nuclear position. Immunohistochemistry revealed typical characteristics of PRNRP, including exclusively positive GATA3 (43/43); highly positive L1CAM (43/43), PAX8 (43/43), and EMA (43/43); and low positive AMACR (4/43), RCC (1/43), and vimentin (1/43). KRAS signaling pathway effectors, such as p-ERK, RalA, and RalB, were highly expressed in PRNRP compared to papillary renal cell carcinoma (pRCC) with low or high nuclear grade (P < .001, all). Compared to pRCC with high nuclear grade, patients with PRNRP exhibited significantly longer progression-free survival (P < .001). PRNRP showed the best clinical outcome, with no disease progression in any of the cases. Our study analyzed the largest number of PRNRP cases and is the first to analyze the association between PRNRP and the KRAS downstream signaling pathway. PRNRP was found at a high frequency among all papillary renal tumors (43/207) and demonstrated a very good prognosis. PRNRP showed high GATA3, L1CAM, PAX8, and EMA protein expression as well as high p-ERK, RalA, and RalB protein expression.

Oncogenic KRAS triggers metabolic reprogramming in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with an extremely high lethality rate. Oncogenic KRAS activation has been proven to be a key driver of PDAC initiation and progression. There is increasing evidence that PDAC cells undergo extensive metabolic reprogramming to adapt to their extreme energy and biomass demands. Cell-intrinsic factors, such as KRAS mutations, are able to trigger metabolic rewriting. Here, we update recent advances in KRAS-driven metabolic reprogramming and the associated metabolic therapeutic potential in PDAC.

Integration and deconvolution methodology deciphering prognosis-related signatures in lung adenocarcinoma

PURPOSE

This study aims to establish a risk prediction model based on prognosis-related genes (PRGs) and clinicopathological factors, and investigate the biological activities of PRGs in lung adenocarcinoma (LUAD).

METHODS

Risk score signatures were developed by employing multiple algorithms and their amalgamations. A predictive model for overall survival was established through the integration of risk score signatures and several clinicopathological parameters. A comprehensive single-cell atlas, gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were used to investigate the biological activities of prognosis-related genes in LUAD.

RESULTS

A risk prediction model was established based on 16 PRGs, exhibiting robust performance in predicting overall survival. The single-cell analysis revealed that epithelial cells were primarily associated with worse survival of LUAD, and PRGs were predominantly enriched in malignant epithelial cells and influenced epithelial cell growth and progression. Furthermore, GSEA and GSVA analysis showed that PRGs were involved in tumor pathways such as epithelial-mesenchymal transition, hypoxia and KRAS_UP, and high GSVA scores are correlated with worse outcome in LUAD patients.

CONCLUSIONS

The constructed risk prediction model in this study offers clinicians a valuable tool for tailoring treatment strategies of LUAD and provides a comprehensive interpretation on the biological activities of PRGs in LUAD.

YB-1 activating cascades as potential targets in KRAS-mutated tumors

Y‑box binding protein‑1 (YB-1) is a multifunctional protein that is highly expressed in human solid tumors of various entities. Several cellular processes, e.g. cell cycle progression, cancer stemness and DNA damage signaling that are involved in the response to chemoradiotherapy (CRT) are tightly governed by YB‑1. KRAS gene with about 30% mutations in all cancers, is considered the most commonly mutated oncogene in human cancers. Accumulating evidence indicates that oncogenic KRAS mediates CRT resistance. AKT and p90 ribosomal S6 kinase are downstream of KRAS and are the major kinases that stimulate YB‑1 phosphorylation. Thus, there is a close link between the KRAS mutation status and YB‑1 activity. In this review paper, we highlight the importance of the KRAS/YB‑1 cascade in the response of KRAS-mutated solid tumors to CRT. Likewise, the opportunities to interfere with this pathway to improve CRT outcome are discussed in light of the current literature.

Managing complications of chronic pancreatitis: a guide for the gastroenterologist

INTRODUCTION

Chronic pancreatitis is a heterogeneous and complex syndrome that, in most cases, causes pain as a cardinal symptom and affects both the morphology and function of the pancreas, leading to several serious complications.

AREAS COVERED

The present review, based on a non-systematic PubMed search updated to June 2023, aims to present the current available evidence on the role of gastroenterologists in the diagnosis and treatment of both local and systemic complications by either endoscopic or medical treatments.

EXPERT OPINION

At diagnosis and during chronic pancreatitis follow-up, particular care is needed to consider not only the clinically manifest signs and symptoms of the disease, such as pain, jaundice, gastrointestinal obstruction, and pseudocysts, which require multidisciplinary discussion to establish the best treatment option (endoscopic or surgical), but also less evident systemic complications. Pancreatic exocrine and endocrine insufficiency, together with chronic inflammation, addiction, and dysbiosis, contribute to malnutrition, sarcopenia, and osteopathy. These complications, in turn, increase the risk of infection, thromboembolic events, and death. Patients with chronic pancreatitis also have an increased risk of psychiatric disorders and pancreatic cancer onset. Overall, patients with chronic pancreatitis should receive a holistic evaluation, considering all these aspects, possibly through multidisciplinary care in dedicated expert centers.

Improving the prognosis of pancreatic cancer: insights from epidemiology, genomic alterations, and therapeutic challenges

Pancreatic cancer, notorious for its late diagnosis and aggressive progression, poses a substantial challenge owing to scarce treatment alternatives. This review endeavors to furnish a holistic insight into pancreatic cancer, encompassing its epidemiology, genomic characterization, risk factors, diagnosis, therapeutic strategies, and treatment resistance mechanisms. We delve into identifying risk factors, including genetic predisposition and environmental exposures, and explore recent research advancements in precursor lesions and molecular subtypes of pancreatic cancer. Additionally, we highlight the development and application of multi-omics approaches in pancreatic cancer research and discuss the latest combinations of pancreatic cancer biomarkers and their efficacy. We also dissect the primary mechanisms underlying treatment resistance in this malignancy, illustrating the latest therapeutic options and advancements in the field. Conclusively, we accentuate the urgent demand for more extensive research to enhance the prognosis for pancreatic cancer patients.

Analysis of the mRNA export protein ZC3H11A in HCMV infection and pan-cancer

Background

We have previously reported that human cytomegalovirus (HCMV) infection could promote the progression of glioma. Here we discovered a stress-induced nuclear protein ZC3H11A (ZC3) through high-throughput sequencing after HCMV infection, which has been reported recently by our research group in regulating mRNA export under stress conditions. And also, a thorough analysis of ZC3 in pan-cancer and the omics data of ZC3 are yet to be conducted.

Methods

The transcriptomes of glioma cells after HCMV infection were assessed by RNA sequencing. ZC3 mRNA and protein level following HCMV infection were validated and measured by qRT-PCR and Western-blot. The RNA sequencing and protein expression information of ZC3 across pan-cancer were analyzed and visualized by R packages. The localization of ZC3 protein was assessed by IHC images from HPA. The ZC3 proteomics and transcriptomics data in different cancers were extracted through the CPTAC data portal, and comparisons were conducted with a Python script. The genetic alteration, survival prognosis, immune infiltration analysis of ZC3 in pan-cancer were analyzed by cBioPortal, TCGA, and TIMER2 databases. The protein interaction networks were revealed by STRING, GEPIA2 and TCGA.

Results

Genes in mRNA processing pathways were upregulated after HCMV infection and ZC3 expression in mRNA and protein level was validated. We also discovered that the status of ZC3 were generally at high levels in cancers, although varied among different cancer types. ZC3 protein in tumor cells localized to the nuclear whereas in normal cells it was mainly found in cytoplasmic/membranous. However, from ZC3 proteomics and transcriptomics data in some cancer types, the increase in ZC3 protein was not accompanied by a significant elevation in mRNA level. Additionally, our analysis indicated that elevated ZC3 expression was primarily linked to a negative prognosis in majority cancers but still varied depending on the cancer types. Our annotation analysis suggested that ZC3-related proteins are mainly involved in mRNA processing clusters.

Conclusion

We demonstrated that ZC3 significantly impacted by HCMV infection in gliomas. Furthermore, we identified a set of genes exhibiting analogous expression patterns to ZC3H11A in TCGA pan-cancer cohorts, implying a potential functional role for ZC3H11A in mRNA processing. Our study provided valuable insights into the role of a new mRNA export protein ZC3 in HCMV infection and pan-cancer progression. These results lay the foundation for our next research on the regulatory mechanism of ZC3 in virus-infected tumors.

The role of diagnostic, prognostic, and predictive biomarkers in the management of early pancreatic cancer

Despite modern advances in cancer medicine, pancreatic cancer survival remains unchanged at just 12%. For the small proportion of patients diagnosed with 'early' (upfront or borderline resectable) disease, recurrences are common, and many recur soon after surgery. Whilst chemotherapy has been shown to increase survival in this cohort, the morbidity of surgery renders many candidates unsuitable for adjuvant treatment. Due to this, and the success of upfront chemotherapy in the advanced setting, use of neoadjuvant chemotherapy has been introduced in patients with upfront or borderline resectable disease. Randomized controlled trials have been conducted to compare upfront surgery to neoadjuvant chemotherapy in this patient cohort, opinions on the ideal upfront treatment approach are divided. This lack of consensus has highlighted the need for biomarkers to assist in clinical decision making. This review analyses the potential diagnostic, prognostic and predictive biomarkers that may assist in the diagnosis and management of early (upfront and borderline resectable) pancreatic cancer.

Tetrandrine synergizes with MAPK inhibitors in treating KRAS-mutant pancreatic ductal adenocarcinoma via collaboratively modulating the TRAIL-death receptor axis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies lacking effective therapies. KRAS mutations that occur in over 90% of PDAC are major oncogenic drivers of PDAC. The MAPK signaling pathway plays a central role in KRAS-driven oncogenic signaling. However, pharmacological inhibitors of the MAPK pathway are poorly responded in KRAS-mutant PDAC, raising a compelling need to understand the mechanism behind and to seek new therapeutic solutions. Herein, we perform a screen utilizing a library composed of 800 naturally-derived bioactive compounds to identify natural products that are able to sensitize KRAS-mutant PDAC cells to the MAPK inhibition. We discover that tetrandrine, a natural bisbenzylisoquinoline alkaloid, shows a synergistic effect with MAPK inhibitors in PDAC cells and xenograft models. Mechanistically, pharmacological inhibition of the MAPK pathway exhibits a double-edged impact on the TRAIL-death receptor axis, transcriptionally upregulating TRAIL yet downregulating its agonistic receptors DR4 and DR5, which may explain the limited therapeutic outcomes of MAPK inhibitors in KRAS-mutant PDAC. Of great interest, tetrandrine stabilizes DR4/DR5 protein via impairing ubiquitination-mediated protein degradation, thereby allowing a synergy with MAPK inhibition in inducing apoptosis in KRAS-mutant PDAC. Our findings identify a new combinatorial approach for treating KRAS-mutant PDAC and highlight the role of TRAIL-DR4/DR5 axis in dictating the therapeutic outcome in KRAS-mutant PDAC.

Targeting KRAS for the potential treatment of pancreatic ductal adenocarcinoma: Recent advancements provide hope (Review)

Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the most frequently mutated oncogenes in solid tumors. More than 90% of pancreatic ductal adenocarcinoma (PDAC) are driven by mutations in the KRAS gene, suggesting the importance of targeting this oncogene in PDAC. Initial efforts to target KRAS have been unsuccessful due to its small size, high affinity for guanosine triphosphate/guanosine diphosphate, and lack of distinct drug‑binding pockets. Therefore, much of the focus has been directed at inhibiting the activation of major signaling pathways downstream of KRAS, most notably the PI3K/AKT and RAF/MAPK pathways, using tyrosine kinase inhibitors and monoclonal antibodies. While preclinical studies showed promising results, clinical data using the inhibitors alone and in combination with other standard therapies have shown limited practicality, largely due to the lack of efficacy and dose‑limiting toxicities. Recent therapeutic approaches for KRAS‑driven tumors focus on mutation‑specific drugs such as selective KRASG12C inhibitors and son of sevenless 1 pan‑KRAS inhibitors. While KRASG12C inhibitors showed great promise against patients with non‑small cell lung cancer (NSCLC) harboring KRASG12C mutations, they were not efficacious in PDAC largely because the major KRAS mutant isoforms in PDAC are G12D, G12V, and G12R. As a result, KRASG12D and pan‑KRAS inhibitors are currently under investigation as potential therapeutic options for PDAC. The present review summarized the importance of KRAS oncogenic signaling, challenges in its targeting, and preclinical and clinical targeted agents including recent direct KRAS inhibitors for blocking KRAS signaling in PDAC.

High WFDC3 gene expression is associated with poor prognosis and reduced immune cells infiltration in pancreatic adenocarcinoma: A study using the TCGA database and bioinformatics analysis

Whey-acidic-protein (WAP) four-disulfide core domain protein 3 (WFDC3) is one of the WAP family proteins. This protein family is associated with the development of solid tumors and affects the tumor immunological microenvironment. However, the prognostic value of WFDC3 in pancreatic adenocarcinoma (PAAD) and its effect on the tumor immune microenvironment is yet to be clarified. The Cancer Genome Atlas database and Genotype-Tissue Expression database were used to analyze the differential expression of WFDC3 between the tumor and adjacent tissues. The clinical significance of WFDC3 was analyzed in The Cancer Genome Atlas and International Cancer Genome Consortium database using WFDC3 transcripts and clinical information. In order to elucidate the underlying mechanisms, gene set enrichment analysis was conducted to determine potential activated pathways. Immune score evaluation and publicly available pharmacogenomics database [the Genomics of Drug Sensitivity in Cancer] were utilized to quantify immune cell infiltration and the effect on chemotherapeutic drug sensitivity. WFDC3 levels were higher in PAAD tissues than in normal pancreatic tissues. High levels of WFDC3 expression progressively increased as PAAD tumor stages progressed. Patients with elevated WFDC3 expression showed a poor prognosis. The gene set enrichment analysis analysis revealed that glutamate, arginine, and proline, and histidine metabolism levels were elevated in patients with a high WFDC3 expression phenotype. B, CD4+ T, and CD8+ T cell infiltration was diminished in PAAD tissues with elevated WFDC3 expression. According to pharmacogenomics, PAAD tissues with high WFDC3 expression are susceptible to gemcitabine. WFDC3 is highly expressed in PAAD, and patients with a high level of WFDC3 expression have a shorter overall survival time, indicating a poorer prognosis. High expression of WFDC3 may lead to the development of PAAD by affecting the amino acid metabolism and the tumor immunological microenvironment. WFDC3 may serve as a potential diagnostic and prognostic biomarker for PAAD patients.

Targeting KRAS in Pancreatic Ductal Adenocarcinoma: The Long Road to Cure

Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of cancer-related mortality, and it is expected to play an even bigger part in cancer burden in the years to come. Despite concerted efforts from scientists and physicians, patients have experienced little improvement in survival over the past decades, possibly because of the non-specific nature of the tested treatment modalities. Recently, the discovery of potentially targetable molecular alterations has paved the way for the personalized treatment of PDAC. Indeed, the central piece in the molecular framework of PDAC is starting to be unveiled. KRAS mutations are seen in 90% of PDACs, and multiple studies have demonstrated their pivotal role in pancreatic carcinogenesis. Recent investigations have shed light on the differences in prognosis as well as therapeutic implications of the different KRAS mutations and disentangled the relationship between KRAS and effectors of downstream and parallel signaling pathways. Additionally, the recognition of other mechanisms involving KRAS-mediated pathogenesis, such as KRAS dosing and allelic imbalance, has contributed to broadening the current knowledge regarding this molecular alteration. Finally, KRAS G12C inhibitors have been recently tested in patients with pancreatic cancer with relative success, and inhibitors of KRAS harboring other mutations are under clinical development. These drugs currently represent a true hope for a meaningful leap forward in this dreadful disease.

Genetic assessment of pathogenic germline alterations in lysosomal genes among Asian patients with pancreatic ductal adenocarcinoma

BACKGROUND

Lysosomes are closely linked to autophagic activity, which plays a vital role in pancreatic ductal adenocarcinoma (PDAC) biology. The survival of PDAC patients is still poor, and the identification of novel genetic factors for prognosis and treatment is highly required to prevent PDAC-related deaths. This study investigated the germline variants related to lysosomal dysfunction in patients with PDAC and to analyze whether they contribute to the development of PDAC.

METHODS

The germline putative pathogenic variants (PPV) in genes involved in lysosomal storage disease (LSD) was compared between patients with PDAC (n = 418) and healthy controls (n = 845) using targeted panel and whole-exome sequencing. Furthermore, pancreatic organoids from wild-type and KrasG12D mice were used to evaluate the effect of lysosomal dysfunction on PDAC development. RNA sequencing (RNA-seq) analysis was performed with established PDAC patient-derived organoids (PDOs) according to the PPV status.

RESULTS

The PPV in LSD-related genes was higher in patients with PDAC than in healthy controls (8.13 vs. 4.26%, Log2 OR = 1.65, P = 3.08 × 10-3). The PPV carriers of LSD-related genes with PDAC were significantly younger than the non-carriers (mean age 61.5 vs. 65.3 years, P = 0.031). We further studied a variant of the lysosomal enzyme, galactosylceramidase (GALC), which was the most frequently detected LSD variant in our cohort. Autophagolysosomal activity was hampered when GALC was downregulated, which was accompanied by paradoxically elevated autophagic flux. Furthermore, the number of proliferating Ki-67+ cells increased significantly in pancreatic organoids derived from Galc knockout KrasG12D mice. Moreover, GALC PPV carriers tended to show drug resistance in both PDAC cell line and PDAC PDO, and RNA-seq analysis revealed that various metabolism and gene repair pathways were upregulated in PDAC PDOs harboring a GALC variant.

CONCLUSIONS

Genetically defined lysosomal dysfunction is frequently observed in patients with young-onset PDAC. This might contribute to PDAC development by altering metabolism and impairing autophagolysosomal activity, which could be potentially implicated in therapeutic applications for PDAC.

Integrated single-cell and bulk RNA sequencing in pancreatic cancer identifies disulfidptosis-associated molecular subtypes and prognostic signature

Pancreatic cancer (PC) is known for its high degree of heterogeneity and exceptionally adverse outcome. While disulfidptosis is the most recently identified form of cell death, the predictive and therapeutic value of disulfidptosis-related genes (DRGs) for PC remains unknown. RNA sequencing data with the follow-up information, were retrieved from the TCGA and ICGC databases. Consensus clustering analysis was conducted on patient data using R software. Subsequently, the LASSO regression analysis was conducted to create a prognostic signature for foreseeing the outcome of PC. Differences in relevant pathways, mutational landscape, and tumor immune microenvironment were compared between PC samples with different risk levels. Finally, we experimentally confirmed the impact of DSG3 on the invasion and migration abilities of PC cells. All twenty DRGs were found to be hyperexpressed in PC tissues, and fourteen of them significantly associated with PC survival. Using consensus clustering analysis based on these DRGs, four DRclusters were identified. Additionally, altogether 223 differential genes were evaluated between clusters, indicating potential biological differences between them. Four gene clusters (geneClusters) were recognized according to these genes, and a 10-gene prognostic signature was created. High-risk patients were found to be primarily enriched in signaling pathways related to the cell cycle and p53. Furthermore, the rate of mutations was markedly higher in high-risk patients, besides important variations were present in terms of immune microenvironment and chemotherapy sensitivity among patients with different risk levels. DSG3 could appreciably enhance the invasion and migration of PC cells. This work, based on disulfidoptosis-related genes (DRGs), holds the promise of classifying PC patients and predicting their prognosis, mutational landscape, immune microenvironment, and drug therapy. These insights could boost an improvement in a better comprehension of the role of DRGs in PC as well as provide new opportunities for prognostic prediction and more effective treatment strategies.

Biological characteristics of pancreatic ductal adenocarcinoma: Initiation to malignancy, intracellular to extracellular

Pancreatic ductal adenocarcinoma (PDAC) is a highly life-threatening tumour with a low early-detection rate, rapid progression and a tendency to develop resistance to chemotherapy. Therefore, understanding the regulatory mechanisms underlying the initiation, development and metastasis of pancreatic cancer is necessary for enhancing therapeutic effectiveness. In this review, we summarised single-gene mutations (including KRAS, CDKN2A, TP53, SMAD4 and some other less prevalent mutations), epigenetic changes (including DNA methylation, histone modifications and RNA interference) and large chromosome alterations (such as copy number variations, chromosome rearrangements and chromothripsis) associated with PDAC. In addition, we discussed variations in signalling pathways that act as intermediate oncogenic factors in PDAC, including PI3K/AKT, MAPK/ERK, Hippo and TGF-β signalling pathways. The focus of this review was to investigate alterations in the microenvironment of PDAC, particularly the role of immunosuppressive cells, cancer-associated fibroblasts, lymphocytes, other para-cancerous cells and tumour extracellular matrix in tumour progression. Peripheral axons innervating the pancreas have been reported to play a crucial role in the development of cancer. In addition, tumour cells can influence the behaviour of neighbouring non-tumour cells by secreting certain factors, both locally and at a distance. In this review, we elucidated the alterations in intracellular molecules and the extracellular environment that occur during the progression of PDAC. Altogether, this review may enhance the understanding of the biological characteristics of PDAC and guide the development of more precise treatment strategies.

Mind the (guidance) signals! Translational relevance of semaphorins, plexins, and neuropilins in pancreatic cancer

Pancreatic cancer is a major cause of demise worldwide. Although key associated genetic changes have been discovered, disease progression is sustained by pathogenic mechanisms that are poorly understood at the molecular level. In particular, the tissue microenvironment of pancreatic adenocarcinoma (PDAC) is usually characterized by high stromal content, scarce recruitment of immune cells, and the presence of neuronal fibers. Semaphorins and their receptors, plexins and neuropilins, comprise a wide family of regulatory signals that control neurons, endothelial and immune cells, embryo development, and normal tissue homeostasis, as well as the microenvironment of human tumors. We focus on the role of these molecular signals in pancreatic cancer progression, as revealed by experimental research and clinical studies, including novel approaches for cancer treatment.

Loss of hepatic FTCD promotes lipid accumulation and hepatocarcinogenesis by upregulating PPARγ and SREBP2

Background & Aims

Exploiting key regulators responsible for hepatocarcinogenesis is of great importance for the prevention and treatment of hepatocellular carcinoma (HCC). However, the key players contributing to hepatocarcinogenesis remain poorly understood. We explored the molecular mechanisms underlying the carcinogenesis and progression of HCC for the development of potential new therapeutic targets.

Methods

The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) and Genotype-Tissue Expression (GTEx) databases were used to identify genes with enhanced expression in the liver associated with HCC progression. A murine liver-specific Ftcd knockout (Ftcd-LKO) model was generated to investigate the role of formimidoyltransferase cyclodeaminase (FTCD) in HCC. Multi-omics analysis of transcriptomics, metabolomics, and proteomics data were applied to further analyse the molecular effects of FTCD expression on hepatocarcinogenesis. Functional and biochemical studies were performed to determine the significance of loss of FTCD expression and the therapeutic potential of Akt inhibitors in FTCD-deficient cancer cells.

Results

FTCD is highly expressed in the liver but significantly downregulated in HCC. Patients with HCC and low levels of FTCD exhibited worse prognosis, and patients with liver cirrhosis and low FTCD levels exhibited a notable higher probability of developing HCC. Hepatocyte-specific knockout of FTCD promoted both chronic diethylnitrosamine-induced and spontaneous hepatocarcinogenesis in mice. Multi-omics analysis showed that loss of FTCD affected fatty acid and cholesterol metabolism in hepatocarcinogenesis. Mechanistically, loss of FTCD upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis.

Conclusions

Taken together, we identified a FTCD-regulated lipid metabolic mechanism involving PPARγ and SREBP2 signaling in hepatocarcinogenesis and provide a rationale for therapeutically targeting of HCC driven by downregulation of FTCD.

Impact and implications

Exploiting key molecules responsible for hepatocarcinogenesis is significant for the prevention and treatment of HCC. Herein, we identified formimidoyltransferase cyclodeaminase (FTCD) as the top enhanced gene, which could serve as a predictive and prognostic marker for patients with HCC. We generated and characterised the first Ftcd liver-specific knockout murine model. We found loss of FTCD expression upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis, and provided a rationale for therapeutic targeting of HCC driven by downregulation of FTCD.

Peritoneal Cell-Free Tumor DNA is a Biomarker of Locoregional and Peritoneal Recurrence in Resected Pancreatic Ductal Adenocarcinomas

BACKGROUND

Recurrence after curative-intent pancreatectomy for pancreatic ductal adenocarcinomas (PDAC) is quite frequent with locoregional and peritoneal recurrence in about one-third of cases. We hypothesize that peritoneal cell-free tumor DNA (ptDNA) present in the intraoperative peritoneal lavage (PL) fluid may be used as a predictive biomarker of locoregional and peritoneal recurrence.

PATIENTS AND METHODS

Under institutional review board (IRB)-approved protocol, pre- and postresection PL fluids were collected from PDAC patients undergoing curative-intent pancreatectomy. PL fluids from PDAC patients with pathologically proven peritoneal metastasis were also collected as positive controls. Cell-free DNA was extracted from PL fluids. Droplet digital PCR (ddPCR) was performed using ddPCR KRAS G12/G13 screening kit. Recurrence-free survival (RFS) based on KRAS-mutant ptDNA level was determined using Kaplan-Meier methods.

RESULTS

KRAS-mutant ptDNA was detected in PL fluids from all PDAC patients. KRAS-mutant ptDNA was detected in 11/21 (52%) preresection and 15/18 (83%) postresection PL fluid samples. With a median follow-up of 23.6 months, 12 patients developed recurrence (8 locoregional/peritoneal recurrence, 9 pulmonary/hepatic recurrence); 5/8 (63%) and 6/6 (100%) patients with mutant allele frequency (MAF) of > 0.10% in pre- and postresection PL fluids, respectively, developed recurrence. Using a cutoff value of 0.10% MAF, the presence of KRAS-mutant ptDNA in postresection PL fluid predicted a significantly shortened time to locoregional and peritoneal recurrence (median RFS of 8.9 months versus not reached, P = 0.003).

CONCLUSIONS

This study suggests that ptDNA in postresection PL fluids may be a useful biomarker to predict locoregional and peritoneal recurrence in resected PDAC patients.

3-Bromopyruvate overcomes cetuximab resistance in human colorectal cancer cells by inducing autophagy-dependent ferroptosis

Colorectal cancer (CRC) remains a leading cause of cancer-related death worldwide. Cetuximab, in combination with chemotherapy, is effective for treating patients with wild-type KRAS/BRAF metastatic CRC (mCRC). However, intrinsic or acquired drug resistance often limits the use of cetuximab. In this study, we investigated the potential of co-treatment with 3-Bromopyruvate (3-BP) and cetuximab to overcome cetuximab resistance in CRC, both in vitro and in vivo. Our results demonstrated that the co-treatment of 3-BP and cetuximab synergistically induced an antiproliferative effect in both CRC cell lines with intrinsic cetuximab resistance (DLD-1 (KRASG13D/-) and HT29 (BRAFV600E)) and in a cetuximab-resistant cell line derived from Caco-2 with acquired resistance (Caco-2-CR). Further analysis revealed that co-treatment induced ferroptosis, autophagy, and apoptosis. Mechanistically, co-treatment inhibited FOXO3a phosphorylation and degradation and activated the FOXO3a/AMPKα/pBeclin1 and FOXO3a/PUMA pathways, leading to the promotion of ferroptosis, autophagy, and apoptosis in DLD-1 (KRASG13D/-), HT29 (BRAFV600E), and Caco-2-CR cells. In conclusion, our findings suggest that co-treatment with 3-BP and cetuximab could be a promising strategy to overcome cetuximab resistance in human CRC.

Cancer-associated fibroblast-related prognostic signature predicts prognosis and immunotherapy response in pancreatic adenocarcinoma based on single-cell and bulk RNA-sequencing

Cancer-associated fibroblasts (CAFs) influence many aspects of pancreatic adenocarcinoma (PAAD) carcinogenesis, including tumor cell proliferation, angiogenesis, invasion, and metastasis. A six-gene prognostic signature was constructed for PAAD based on the 189 CAF marker genes identified in single-cell RNA-sequencing data. Multivariate analyses showed that the risk score was independently prognostic for survival in the TCGA (P < 0.001) and ICGC (P = 0.004) cohorts. Tumor infiltration of CD8 T (P = 0.005) cells and naïve B cells (P = 0.001) was greater in the low-risk than in the high-risk group, with infiltration of these cells negatively correlated with risk score. Moreover, the TMB score was lower in the low-risk than in the high-risk group (P = 0.0051). Importantly, patients in low-risk group had better immunotherapy responses than in the high-risk group in an independent immunotherapy cohort (IMvigor210) (P = 0.039). The CAV1 and SOD3 were highly expressed in CAFs of PAAD tissues, which revealed by immunohistochemical staining. In summary, this comprehensive analysis resulted in the development of a novel prognostic signature, which was associated with immune cell infiltration, drug sensitivity, and TMB, and could predict the prognosis and immunotherapy response of patients with PAAD.

Development and validation of cuproptosis-related lncRNAs associated with pancreatic cancer immune microenvironment based on single-cell

Background

Cuproptosis, a novel mode of cell death associated with the tricarboxylic acid (TCA) cycle, is relevant to the development of cancer. However, the impact of single-cell-based Cuproptosis-associated lncRNAs on the Tumor immune microenvironment (TIME) of Pancreatic adenocarcinoma (PAAD) and its potential value for individualized immunotherapy has not been clarified.

Methods

14 immune-related CRGs were screened by exploring the interaction between differentially expressed Immune-Related Genes (IRGs) and Cuproptosis-Related Genes (CRGs) in PAAD. Next, the expression amount and expression distribution of CRGs in single-cell samples were analyzed by focusing on 7-CRGs with significant expressions. On the one hand, MAP2K2, SOD1, and VEGFA, which were significantly differentially expressed between PAAD sites and normal tissues adjacent to them, were subjected to immunohistochemical validation and immune landscape analysis. On the other hand, from these 7-CRGs, prognostic signatures of lncRNAs were established by co-expression and LASSO-COX regression analysis, and their prognostic value and immune relevance were assessed. In addition, this study not only validated the hub CRGs and the lncRNAs constituting the signature in a PAAD animal model treated with immunotherapy-based combination therapy using immunohistochemistry and qRT-PCR but also explored the potential value of the combination of targeted, chemotherapy and immunotherapy.

Results

Based on the screening of 7-CRGs significantly expressed in a PAAD single-cell cohort and their co-expressed Cuproptosis-Related lncRNAs (CRIs), this study constructed a prognostic signature of 4-CRIs named CIR-score. A Nomogram integrating the CIR-score and clinical risk factors was constructed on this basis to predict the individualized survival of patients. Moreover, high and low-risk groups classified according to the median of signatures exhibited significant differences in clinical prognosis, immune landscape, bioenrichment, tumor burden, and drug sensitivity. And the immunohistochemical and qRT-PCR results of different mouse PAAD treatment strategies were consistent with the trend of inter-group variability in drug sensitivity of hub CRGs and CIR-score. The combination of immunotherapy, targeted therapy, and chemotherapy exhibited a better tumor suppression effect.

Conclusion

CIR-score, as a Cuproptosis-related TIME-specific prognostic signature based on PAAD single cells, not only predicts the prognosis and immune landscape of PAAD patients but also provides a new strategy for individualized immunotherapy-based combination therapy.

Exploiting the molecular subtypes and genetic landscape in pancreatic cancer: the quest to find effective drugs

Pancreatic Ductal Adenocarcinoma (PDAC) is a very lethal disease that typically presents at an advanced stage and is non-compliant with most treatments. Recent technologies have helped delineate associated molecular subtypes and genetic variations yielding important insights into the pathophysiology of this disease and having implications for the identification of new therapeutic targets. Drug repurposing has been evaluated as a new paradigm in oncology to accelerate the application of approved or failed target-specific molecules for the treatment of cancer patients. This review focuses on the impact of molecular subtypes on key genomic alterations in PDAC, and the progress made thus far. Importantly, these alterations are discussed in light of the potential role of drug repurposing in PDAC.

A Novel HOXA10-Associated 5-Gene-Based Prognostic Signature for Stratification of Short-term Survivors of Pancreatic Ductal Adenocarcinoma

PURPOSE

Despite the significant association of molecular subtypes with poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC), few efforts have been made to identify the underlying pathway(s) responsible for this prognosis. Identifying a clinically relevant prognosis-based gene signature may be the key to improving patient outcomes.

EXPERIMENTAL DESIGN

We analyzed the transcriptomic profiles of treatment-naïve surgically resected short-term survivor (STS) and long-term survivor (LTS) tumors (GSE62452) for expression and survival, followed by validation in several datasets. These results were corroborated by IHC analysis of PDAC-resected STS and LTS tumors. The mechanism of this differential survival was investigated using CIBERSORT and pathway analyses.

RESULTS

We identified a short-surviving prognostic subtype of PDAC with a high degree of significance (P = 0.018). One hundred thirty genes in this novel subtype were found to be regulated by a master regulator, homeobox gene HOXA10, and a 5-gene signature derived from these genes, including BANF1, EIF4G1, MRPS10, PDIA4, and TYMS, exhibited differential expression in STSs and a strong association with poor survival. This signature was further associated with the proportion of T cells and macrophages found in STSs and LTSs, demonstrating a potential role in PDAC immunosuppression. Pathway analyses corroborated these findings, revealing that this HOXA10-driven prognostic signature is associated with immune suppression and enhanced tumorigenesis.

CONCLUSIONS

Overall, these findings reveal the presence of a HOXA10-associated prognostic subtype that can be used to differentiate between STS and LTS patients of PDAC and inform on the molecular interactions that play a role in this poor prognosis.

Mutant KRAS Mediates circARFGEF2 Biogenesis to Promote Lymphatic Metastasis of Pancreatic Ductal Adenocarcinoma

Circular RNAs (circRNA) contribute to cancer stemness, proliferation, and metastasis. The biogenesis of circRNAs can be impacted by the genetic landscape of tumors. Herein, we identified a novel circRNA, circARFGEF2 (hsa_circ_0060665), which was upregulated in KRASG12D pancreatic ductal adenocarcinoma (PDAC) and positively associated with KRASG12D PDAC lymph node (LN) metastasis. CircARFGEF2 overexpression significantly facilitated KRASG12D PDAC LN metastasis in vitro and in vivo. Mechanistically, circARFGEF2 biogenesis in KRASG12D PDAC was significantly activated by the alternative splicing factor QKI-5, which recruited U2AF35 to facilitate spliceosome assembly. QKI-5 bound the QKI binding motifs and neighboring reverse complement sequence in intron 3 and 6 of ARFGEF2 pre-mRNA to facilitate circARFGEF2 biogenesis. CircARFGEF2 sponged miR-1205 and promoted the activation of JAK2, which phosphorylated STAT3 to trigger KRASG12D PDAC lymphangiogenesis and LN metastasis. Importantly, circARFGEF2 silencing significantly inhibited LN metastasis in the KrasG12D/+Trp53R172H/+Pdx-1-Cre (KPC) mouse PDAC model. These findings provide insight into the mechanism and metastasis-promoting function of mutant KRAS-mediated circRNA biogenesis.

SIGNIFICANCE

Increased splicing-mediated biogenesis of circARFGEF2 in KRAS-mutant pancreatic ductal adenocarcinoma activates JAK2-STAT3 signaling and triggers lymph node metastasis, suggesting circARFGEF2 could be a therapeutic target to inhibit pancreatic cancer progression.