Biology subjects

Corbo, V.

Publications and source records attributed to Corbo, V..

6 recordsLinked to original sources

bioRxiv2024

SMAD4 and KRAS status shape malignant-stromal crosstalk in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) contains an extensive stroma that modulates response to therapy, contributing to the dismal prognosis associated with this cancer. Evidence suggests that the stromal composition of PDAC is shaped by mutations within malignant cells; however, most pre-clinical models of PDAC are driven by KrasG12D and mutant Trp53 and have not assessed the contribution of other known oncogenic drivers, including KRASG12V and alterations in CDKN2A and SMAD4. To increase understanding of malignant cell-stroma crosstalk in PDAC, we analyzed Trp53-mutant mouse models driven by KrasG12D or KrasG12V in which Smad4 was wild-type or deleted. KrasG12D; Smad4-deleted PDAC developed a fibro-inflammatory rich stroma with increased JAK/STAT malignant cell signaling and an enhanced therapeutic response to JAK/STAT inhibition. In stark contrast, the stroma of Smad4-deleted KrasG12V PDAC was differently altered, and the malignant compartment lacked JAK/STAT signaling dependency. Thus, malignant cell genotype impacts malignant-stromal phenotype in PDAC, directly affecting therapeutic efficacy. STATEMENT OF SIGNIFICANCEUnderstanding malignant cell-stroma crosstalk in PDAC has focused on models containing KrasG12D and mutant Trp53. Here, we show that PDAC driven by KrasG12D or KrasG12Vin which Smad4 is deleted display differences in malignant-stromal signaling and treatment sensitivity, highlighting the importance of understanding genotype-phenotype relationships for precision PDAC therapy.

cancer biology↗

bioRxiv2023

Differential Activity of MAPK signalling Defines Fibroblast Subtypes in Pancreatic Cancer

Fibroblast heterogeneity is increasingly recognised across cancer conditions. Given their important contribution to disease progression, mapping out fibroblasts heterogeneity is critical to devise effective anti-cancer therapies. Cancer-associated fibroblasts (CAFs) represent the most abundant cell population in pancreatic ductal adenocarcinoma (PDAC). Whether CAF phenotypes are differently specified by PDAC cell lineages remains to be elucidated. Here, we reveal an important role for the MAPK signalling pathway in the definition of PDAC CAF phenotypes. We identify the myCAF transcriptional phenotype as uniquely dependent on proficient MAPK signalling. In addition, CAFs displaying elevated MAPK activity are specifically anchored to basal-like/squamous PDAC cells and define tumour subdomains with reduced frequency of CD8+ T cells. We characterize the single-cell transcriptome of mouse PDAC tumours in response to MAPK inhibition and identify gene expression signatures of MAPKhigh CAFs, which suggest immunoregulatory functions. Accordingly, a gene expression signature of MAPKhigh CAFs correlates with poor prognosis in several human cancer conditions, including PDAC, and with reduced response to immune checkpoint inhibition in immune-reactive solid tumours. Altogether, our data expand our knowledge on CAF phenotype heterogeneity and reveal a new strategy for targeting of myofibroblastic CAFs in vivo.

cancer biology↗

bioRxiv2023

ecDNA amplification of MYC drives intratumor copy-number heterogeneity and adaptation to stress in PDAC

Intratumor heterogeneity and phenotypic plasticity drive tumour progression and therapy resistance. Oncogene dosage variation contributes to cell state transitions and phenotypic heterogeneity, thereby providing a substrate for somatic evolution. Nonetheless, the genetic mechanisms underlying phenotypic heterogeneity are still poorly understood. Here, we show that extrachromosomal DNA (ecDNA) is a major source of high-level focal amplification in key oncogenes and a major contributor of MYC heterogeneity in pancreatic ductal adenocarcinoma (PDAC). We demonstrate that ecDNA can drive exceptionally high dosage of MYC and afford cancer cells rapid adaptation to microenvironmental changes. The continued maintenance of extrachromosomal MYC is uniquely ensured by the presence of the selective pressure. We also show that MYC dosage affects cell morphology and dependence of cancer cells on stromal niche factors, with the highest MYC levels correlating with squamous-like phenotypes. Our work provides the first detailed analysis of ecDNAs in PDAC and describes a new genetic mechanism driving MYC heterogeneity in PDAC.

cancer biology↗

bioRxiv2023

The axon guidance cue SEMA3A promotes the aggressive phenotype of basal-like PDAC

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with few available therapeutic options. Two transcriptional cancer cell states have been consistently reported in PDAC, with the basal-like/squamous phenotype displaying a more aggressive biological behavior. Genetic and epigenetic dysregulation of the axon guidance pathway are common in PDAC, yet our understanding of its biological relevance is limited. Here, we investigated the functional role of the axon guidance cue SEMA3A in sustaining the progression of PDAC. We integrated available transcriptomic datasets of human PDAC with in situ hybridization analyses of patients tissues to find that SEMA3A is expressed by stromal cells and selectively enriched in epithelial cells of the basal-like/squamous subtype. We found that both cell-intrinsic and cell extrinsic factors instructing the basal-like/squamous subtype induce expression of SEMA3A in PDAC cells. In vitro, SEMA3A promoted cell migration as well as anoikis resistance. At molecular level, these phenotypes were associated with increased FAK signaling and enrichment of gene programs related to cytoskeleton remodeling. Accordingly, SEMA3A provided mouse PDAC cells with greater metastatic competence. In mouse orthotopic allografts, SEMA3A remodeled the TME by favoring infiltration of tumor-associated macrophages and exclusion of T cells. Mechanistically, SEMA3A functioned as chemoattractant for macrophages and favored their polarization towards an M2-like phenotype. In SEMA3Ahigh tumors, depletion of macrophages resulted in greater intratumor infiltration by CD8+ T cells and increased sensitivity of these tumors to chemotherapy. Overall, we show that SEMA3A contributes to the malignant phenotype of basal-like PDAC.

cancer biology↗

bioRxiv2022

Transcriptomic dissection of Intraepithelial Papillary Mucinous Neoplasms progression by spatial technologies identified novel markers of pancreatic carcinogenesis.

Intraductal papillary mucinous neoplasms (IPMN) are one of the main precursor lesions of Pancreatic Ductal Adenocarcinoma (PDAC). The number of patients diagnosed with IPMN is constantly increasing. While in most of the cases IPMN present as indolent and nonmalignant entities, some degenerate into PDAC. The main mechanisms behind the IPMN progression to malignancy is still not fully understood. This is mainly due to the technological limit of the analyzes and to cysts heterogeneity whose malignant transformation potential is estimated based on size and degree of dysplasia without take in consideration the transformation time and therefore the real malignancy potential. Moreover, there is a general lack of consensus diagnostic markers to discern the Low-grade nonmalignant from High-grade malignant IPMN. In this study, we used two different Spatial Transcriptomic technologies (Visium, and GeoMx) to investigate the transcriptome of Low-grade dysplasia nonmalignant IPMN, Borderline IPMN, and High-grade dysplasia malignant IPMN to dissect the main mechanism that drives carcingenesis and to find specific markers associated to risk of tumor progression. We performed Visium spatial transcriptomics on two TMAs containing three Low-grade dysplasia nonmalignant IPMN, one Borderline IPMN, two High-grade dysplasia malignant IPMN, and two PDAC. We identified three specific epithelial cell clusters that characterize Low-grade dysplasia IPMN, Borderline IPMN, and High-grade dysplasia malignant IPMN and three transcription factors whose expression is associated with each grade. High-grade malignant IPMN were characterized by high expression levels of NKX6-2 and other markers of gastric isthmus cell lineage such as MUC5AC, PSCA, FERIL6. The SPDEF high IPMN cluster was found in Borderline IPMN and spotted in some regions of High-grade malignant IPMN. This cluster was characterized by high expression levels of SPDEF and other goblet cell lineage markers such as TFF2, AQP5, and MUC6. Low-grade nonmalignant IPMN were characterized by high expression levels of HOXB3, HOXB5, ZNF117. The association of these markers with the different grades was validated by GeoMx spatial transcriptomics on 43 additional IPMN samples divided according to their grade of dysplasia and malignancy. To better understand the transcriptomic changes along IPMN progression we performed spatial trajectory inference and we found that SPDEF high IPMN cluster cells are likely to evolve into NKX6-2 high malignant IPMN, and we found that this switch is characterized by the expression of NKX6-2 and other gastric markers. Taken together, the results presented here not only shed more light in to IPMN and PDAC oncogenesis, but also provided a plethora of novel malignancy-associated markers to be tested in diagnostic routine, to better delineate IPMN progression in patients and improve clinical management.

cancer biology↗

bioRxiv2019

MAP Kinase inhibition reshapes tumor microenvironment of mouse pancreatic cancer by depleting anti-inflammatory macrophages

The RAF/MEK/ERK (MAP Kinase) pathway is the index oncogenic signaling towards which many compounds have been developed and tested for the treatment of KRAS-driven cancers, including pancreatic ductal adenocarcinoma (PDA). Here, we explored the immunological changes induced by targeted MEK1/2 inhibition (MEKi) using trametinib in preclinical mouse models of PDA. We evaluated the dynamic changes in the immune contexture of mouse PDA upon MEKi using a multidimensional approach (mRNA analyses, flow cytometry, and immunophenotyping). Effect of MEKi on the viability and metabolism of macrophages was investigated in vitro. We showed that transcriptional signatures of MAP Kinase activation are enriched in aggressive human PDA subtype (squamous/basal-like/quasimesenchymal), while short term MEKi treatment in mouse PDA induced subtype switching. Integrative mRNA expression and immunophenotypic analyses showed that MEKi reshapes the immune landscape of PDA by depleting rather than reprogramming macrophages, while augmenting infiltration by neutrophils. Depletion of macrophages is observed early in the course of in vivo treatment and is at least partially due to their higher sensitivity to MEKi. Tumor-associated macrophages were consistently reported to interfere with gemcitabine uptake by PDA cells. Here, our in vivo studies show a superior antitumor activity upon combination of MEKi and gemcitabine using a sequential rather than simultaneous dosing protocol. Our results show that MEK inhibition induces a dramatic remodeling of the tumor microenvironment of mouse PDA through depletion of macrophages, which substantially improves the antitumor activity of gemcitabine.

cancer biology↗