Pancreatic stellate cells (PSCs) secrete high levels of transforming growth factor-β1 (TGF-β1) that contributes to the development of pancreatic ductal adenocarcinoma (PDAC). TGF-β1 modulates the expression of L1 cell adhesion molecule (L1CAM), but its role in tumour progression still remains controversial. To clarify L1 function in PDAC and cellular phenotypes, we performed L1CAM cell sorting, silencing and overexpression in several primary pancreatic cancer cells. PSCs silenced for TGF-β1 were used for crosstalk experiments. We found that TGF-β1 secreted by PSCs negatively regulates L1CAM expression, through canonical TGF-β-Smad2/3 signalling, leading to a more aggressive PDAC phenotype. Cells with reduced expression of L1CAM harboured enhanced stemness potential and tumourigenicity. Inactivation of TGF-β1 signalling in PSCs strongly reduced the aggressiveness of PDAC cells. Our data provide functional proof and mechanistic insights for the tumour-suppressive function of L1CAM via reducing stemness. Rescuing L1CAM expression in cancer cells through targeting of TGF-β1 reverses stemness and bears the potential to improve the still miserable prognosis of PDAC patients.

Background: Tumor-initiating cells (TIC), also known as cancer stem cells, are considered a specific subpopulation of cells necessary for cancer initiation and metastasis; however, the mechanisms by which they acquire metastatic traits are not well understood. Methods: LAMC2 transcriptional levels were evaluated using publicly available transcriptome data sets, and LAMC2 immunohistochemistry was performed using a tissue microarray composed of PDAC and normal pancreas tissues. Silencing and tracing of LAMC2 was performed using lentiviral shRNA constructs and CRISPR/Cas9-mediated homologous recombination, respectively. The contribution of LAMC2 to PDAC tumorigenicity was explored in vitro by tumor cell invasion, migration, sphere-forming and organoids assays, and in vivo by tumor growth and metastatic assays. mRNA sequencing was performed to identify key cellular pathways upregulated in LAMC2 expressing cells. Metastatic spreading induced by LAMC2- expressing cells was blocked by pharmacological inhibition of transforming growth factor beta (TGF-β) signaling. Results: We report a LAMC2-expressing cell population, which is endowed with enhanced self-renewal capacity, and is sufficient for tumor initiation and differentiation, and drives metastasis. mRNA profiling of these cells indicates a prominent squamous signature, and differentially activated pathways critical for tumor growth and metastasis, including deregulation of the TGF-β signaling pathway. Treatment with Vactosertib, a new small molecule inhibitor of the TGF-β type I receptor (activin receptor-like kinase-5, ALK5), completely abrogated lung metastasis, primarily originating from LAMC2-expressing cells. Conclusions: We have identified a highly metastatic subpopulation of TICs marked by LAMC2. Strategies aimed at targeting the LAMC2 population may be effective in reducing tumor aggressiveness in PDAC patients. Our results prompt further study of this TIC population in pancreatic cancer and exploration as a potential therapeutic target and/or biomarker.

The small molecule Galunisertib (LY2157299, LY) shows multiple anticancer activities blocking the transforming growth factor‐β1 receptor, responsible for the epithelial‐to‐mesenchymal transition (EMT) by which colorectal cancer (CRC) cells acquire migratory and metastatic capacities. However, frequent dosing of LY can produce highly toxic metabolites. Alternative strategies to reduce drug side effects can rely on nanoscale drug delivery systems that have led to a medical revolution in the treatment of cancer, improving drug efficacy and lowering drug toxicity. Here, a hybrid nanosystem (DNP‐AuNPs‐LY@Gel) made of a porous diatomite nanoparticle decorated with plasmonic gold nanoparticles, in which LY is retained by a gelatin shell, is proposed. The multifunctional capability of the nanosystem is demonstrated by investigating the efficient LY delivery, the enhanced EMT reversion in CRCs and the intracellular quantification of drug release with a sub‐femtogram resolution by surface‐enhanced Raman spectroscopy (SERS). The LY release trigger is the pH sensitivity of the gelatin shell to the CRC acidic microenvironment. The drug release is real‐time monitored at single‐cell level by analyzing the SERS signals of LY in CRC cells. The higher efficiency of LY delivered by the DNP‐AuNPs‐LY@Gel complex paves the way to an alternative strategy for lowering drug dosing and consequent side effects.

Pancreatic cancer, the fourth most common cancer worldwide, shows a highly unsuccessful therapeutic response. In the last 10 years, neither important advancements nor new therapeutic strategies have significantly impacted patient survival, highlighting the need to pursue new avenues for drug development discovery and design. Advanced cellular models, resembling as much as possible the original in vivo tumor environment, may be more successful in predicting the efficacy of future anti-cancer candidates in clinical trials. In this review, we discuss novel bioengineered platforms for anticancer drug discovery in pancreatic cancer, from traditional two-dimensional models to innovative three-dimensional ones.

Background: Colorectal cancer (CRC) is currently the third leading cause for cancer-related mortality. Cancer stem cells have been implicated in colorectal tumor growth, but their specific role in tumor biology, including metastasis, is still uncertain.

Background: Metastasis-initiating cells are key players in progression, resistance, and relapse of colorectal cancer (CRC), by leveraging the regulatory relationship between Transforming Growth Factor-beta (TGF-β) signaling and anti-L1 cell adhesion molecule (L1CAM). Methods: This study introduces a novel strategy for CRC targeted therapy and imaging based on the use of a hybrid nanosystem made of gold nanoparticles-covered porous biosilica further modified with the (L1CAM) antibody. Results: The nanosystem intracellularly delivers galunisertib (LY), a TGF-β inhibitor, aiming to inhibit epithelial-mesenchymal transition (EMT), a process pivotal for metastasis. Anti-L1CAM antibody-functionalized nanoparticles (NPs) target tumor-initiating cells expressing L1CAM, inhibiting cancer growth. The number of antibody molecules conjugated to the single NP is precisely quantified, revealing a high surface coverage that facilitates the tumor targeting. The therapeutic efficacy of the nanosystem is investigated in organoid-like cultures of CRC cells and in vivo mouse models, showing a significant reduction in tumor growth. The spatial distribution of NPs within CRC tumors from mice is investigated using a label-free optical approach based on Raman micro-spectroscopy. Conclusion: This research highlights the multifunctional capabilities of engineered biosilica NPs, which offer new insights in targeted CRC therapy and imaging, improving patient outcomes and paving the way for personalized therapies.