Dataset Information

NF1 loss of function as an alternative initiating event in pancreatic ductal adenocarcinoma.

ABSTRACT: A long-standing question in the pancreatic ductal adenocarcinoma (PDAC) field has been whether alternative genetic alterations could substitute for oncogenic KRAS mutations in initiating malignancy. Here, we report that Neurofibromin1 (NF1) inactivation can bypass the requirement of mutant KRAS for PDAC pathogenesis. An in-depth analysis of PDAC databases reveals various genetic alterations in the NF1 locus, including nonsense mutations, which occur predominantly in tumors with wild-type KRAS. Genetic experiments demonstrate that NF1 ablation culminates in acinar-to-ductal metaplasia, an early step in PDAC. Furthermore, NF1 haploinsufficiency results in a dramatic acceleration of Kras^G12D-driven PDAC. Finally, we show an association between NF1 and p53 that is orchestrated by PML, and mosaic analysis with double markers demonstrates that concomitant inactivation of NF1 and Trp53 is sufficient to trigger full-blown PDAC. Together, these findings open up an exploratory framework for apprehending the mechanistic paradigms of PDAC with normal KRAS, for which no effective therapy is available.

SUBMITTER: Ramakrishnan G

PROVIDER: S-EPMC9716579 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

NF1 loss of function as an alternative initiating event in pancreatic ductal adenocarcinoma.

Ramakrishnan Gopalakrishnan G Parajuli Parash P Singh Pura P Friend Creighton C Hurwitz Eric E Prunier Celine C Razzaque Mohammed S MS Xu Keli K Atfi Azeddine A

Cell reports 20221101 6

A long-standing question in the pancreatic ductal adenocarcinoma (PDAC) field has been whether alternative genetic alterations could substitute for oncogenic KRAS mutations in initiating malignancy. Here, we report that Neurofibromin1 (NF1) inactivation can bypass the requirement of mutant KRAS for PDAC pathogenesis. An in-depth analysis of PDAC databases reveals various genetic alterations in the NF1 locus, including nonsense mutations, which occur predominantly in tumors with wild-type KRAS. G ...[more]

PMID: 36351408

Similar Datasets

Project description:BackgroundSMAD4 is a gastrointestinal malignancy-specific tumor suppressor gene found mutated in one third of colorectal cancer specimens and half of pancreatic tumors. SMAD4 inactivation by allelic deletion or intragenic mutation mainly occurs in the late stage of human pancreatic ductal adenocarcinoma (PDAC). Various studies have proposed potential SMAD4-mediated anti-tumor effects in human malignancy; however, the relevance of SMAD4 in the PDAC molecular phenotype has not yet been fully characterized.MethodsThe AsPC-1, CFPAC-1 and PANC-1 human PDAC cell lines were used. The restoration or knockdown of SMAD4 expression in PDAC cells were confirmed by western blotting, luciferase reporter and immunofluorescence assays. In vitro cell proliferation, xenograft, wound healing, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry analysis were conducted using PDAC cells in which SMAD4 was either overexpressed or knocked down.ResultsHere, we report that re-expression of SMAD4 in SMAD4-null PDAC cells does not affect tumor cell growth in vitro or in vivo, but significantly enhances cells migration in vitro. SMAD4 restoration transcriptionally activates the TGF-?1/Nestin pathway and induces expression of several transcriptional factors. In contrast, SMAD4 loss in PDAC leads to increased expression of E-cadherin, vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR) and CD133. Furthermore, SMAD4 loss causes alterations to multiple kinase pathways (particularly the phosphorylated ERK/p38/Akt pathways), and increases chemoresistance in vitro. Finally, PDAC cells with intact SMAD4 are more sensitive to TGF-?1 inhibitor treatment to reduced cell migration; PDAC cells lacking SMAD4 showed decreased cell motility in response to EGFR inhibitor treatment.ConclusionsThis study revealed the molecular basis for SMAD4-dependent differences in PDAC with the aim of identifying the subset of patients likely to respond to therapies targeting the TGF-? or EGFR signaling pathways and of identifying potential therapeutic interventions for PDAC patients with SMAD4 defects.

Project description:BackgroundPancreatic ductal adenocarcinoma (PDAC) is highly associated with cachexia and weight loss, which is driven by the tumour's effect on the body. Data are lacking on differences in these metrics based on PDAC anatomic location. We hypothesize that the primary tumour's anatomic region influences the prevalence and severity of unintentional weight loss.MethodsTreatment naïve patients with PDAC who underwent pancreatectomy at a single institution between 2012 and 2020 were identified retrospectively. Patients with pancreatic head or distal tumours were matched by sex, age, N and T stage. Serologic and anthropometric variables were obtained at the time of diagnosis. Skeletal muscle index (SMI), muscle radiation attenuation (MRA) and adiposity were measured. The primary outcome was presence of significant weight loss [>5% body weight (BW) loss in past 6 months]. Signed rank tests, Cochran Mantel Haenszel tests and Kaplan-Meier survival analysis are presented. RNA-seq of tumours was performed to explore enriched pathways related to cachexia and weight loss.ResultsPancreatic head tumours (n = 24) were associated with higher prevalence (70.8% vs. 41.7%, P = 0.081) and degree of weight loss (7.9% vs. 2.5%, P = 0.014) compared to distal tumours (n = 24). BMI (P = 0.642), SMI (P = 0.738) and MRA (P = 0.478) were similar between groups. Combining BW loss, SMI and MRA into a composite score, patients with pancreatic head cancers met more criteria associated with poor prognosis (P = 0.142). Serum albumin (3.9 vs. 4.4 g/dL, P = 0.002) was lower and bilirubin (4.5 vs. 0.4 mg/dL, P < 0.001) were higher with pancreatic head tumours. Survival differed by tumour location (P = 0.014) with numerically higher median overall survival with distal tumours (11.1 vs. 21.8 months; P = 0.066). Transcriptomic analysis revealed inactivation of appetite stimulation, weight regulation and nutrient digestion/metabolism pathways in pancreatic head tumours.ConclusionsResectable pancreatic head PDAC is associated with higher prevalence of significant weight loss and more poor prognosis features. Pancreaticobiliary obstruction and hypoalbuminemia in patients with head tumours suggests compounding effects of nutrient malabsorption and systemic inflammation on molecular drivers of cachexia, possibly contributing to shorter survival. Therefore, PDAC-associated cachexia is a heterogenous syndrome, which may be influenced by the primary tumour location. Select patients with resectable pancreatic head tumours may benefit from nutritional rehabilitation to improve outcomes.

Dataset Information

NF1 loss of function as an alternative initiating event in pancreatic ductal adenocarcinoma.

Publications

NF1 loss of function as an alternative initiating event in pancreatic ductal adenocarcinoma.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets