Cancer-associated fibroblasts (CAF) and nerves, components of the tumor microenvironment, have each been shown to directly promote gastrointestinal cancers. However, it remains unknown whether these cells interact with each other to regulate cancer progression. We found that in colorectal cancer, norepinephrine induces ADRB2 (β2-adrenergic receptor)–dependent nerve growth factor (NGF) secretion from CAFs, which in turn increases intratumor sympathetic innervation and norepinephrine accumulation. Adrenergic stimulation accelerates colorectal cancer growth through ADRA2A/Gi-mediated activation of Yes-associated protein (YAP). NGF from CAFs directly enhances colorectal cancer cell growth via the phosphatidylinositol-3-kinase/AKT pathway. Treatment with a tropomyosin receptor kinase (TRK) inhibitor decreased YAP and AKT activation and colorectal cancer progression in mice. In human colorectal cancer, high NGF expression is associated with mesenchymal-like tumor subtype and poor patient survival. These findings suggest a central role for reciprocal CAF–nerve cross-talk in promoting colorectal cancer progression. Blocking this feedforward loop with a TRK inhibitor may represent a potential therapeutic approach for colorectal cancer. Significance: Our work demonstrates that the bidirectional interplay between sympathetic nerves and NGF-expressing CAFs drives colorectal tumorigenesis. This study also offers novel mechanistic insights into catecholamine action in colorectal cancer. Inhibiting the neuro-mesenchymal interaction by TRK blockade could be a potential strategy for treating colorectal cancer.

We aimed to develop a new artificial intelligence (AI)-based method for evaluating endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) specimens in pancreatic diseases using deep learning and contrastive learning. We analysed a total of 173 specimens from 96 patients who underwent EUS-FNB with a 22 G Franseen needle for pancreatic diseases. In the initial study, the deep learning method based on stereomicroscopic images of 98 EUS-FNB specimens from 63 patients showed an accuracy of 71.8% for predicting the histological diagnosis, which was lower than that of macroscopic on-site evaluation (MOSE) performed by EUS experts (81.6%). Then, we used image analysis software to mark the core tissues in the photomicrographs of EUS-FNB specimens after haematoxylin and eosin staining and verified whether the diagnostic performance could be improved by applying contrastive learning for the features of the stereomicroscopic images and stained images. The sensitivity, specificity, and accuracy of MOSE were 88.97%, 53.5%, and 83.24%, respectively, while those of the AI-based diagnostic method using contrastive learning were 90.34%, 53.5%, and 84.39%, respectively. The AI-based evaluation method using contrastive learning was comparable to MOSE performed by EUS experts and can be a novel objective evaluation method for EUS-FNB.

A well-known feature of human pancreatic ductal adenocarcinoma (PDAC) is the extensive proliferation of cancer-associated fibroblasts (CAFs) and highly fibrotic stroma. Recent evidence, based mainly on single-cell analyses, has identified various subsets of CAFs in PDAC mouse models. However, we do not know how these CAF subsets are involved in the progression and drug resistance of human PDAC. Additionally, it remains unclear whether these diverse CAFs have distinct origins and are indicators of genuinely distinct CAF lineages or reflect different states of the same CAFs depending on the tumor microenvironment. Interestingly, recent preclinical studies have started to characterize the nature of cancer-restraining CAFs and have identified their markers Meflin and collagen type I alpha 1. These studies have led to the development of strategies to induce changes in CAF phenotypes using chemical reagents or recombinant viruses, and some of them have been tested in clinical studies. These strategies have the unique potential to convert the so-called bad stroma to good stroma and may also have therapeutic implications for non-cancer diseases such as fibrotic diseases. Together with recently developed sophisticated strategies that specifically target distinct CAF subsets via adoptive cell transfer therapy, vaccination, and antibody–drug conjugates, any future findings arising from these clinical efforts may expand our understanding of the significance of CAF diversity in human PDAC.

Background: The proliferation of cancer-associated fibroblasts (CAFs) hampers drug delivery and anti-tumor immunity, inducing tumor resistance to immune checkpoint blockade (ICB) therapy. However, it has remained a challenge to develop therapeutics that specifically target or modulate CAFs. Methods: We investigated the involvement of Meflin⁺ cancer-restraining CAFs (rCAFs) in ICB efficacy in patients with clear cell renal cell carcinoma (ccRCC) and urothelial carcinoma (UC). We examined the effects of Am80 (a synthetic retinoid) administration on CAF phenotype, the tumor immune microenvironment, and ICB efficacy in cancer mouse models. Results: High infiltration of Meflin⁺ CAFs correlated with ICB efficacy in patients with ccRCC and UC. Meflin⁺ CAF induction by Am80 administration improved ICB efficacy in the mouse models of cancer. Am80 exerted this effect when administered prior to, but not concomitant with, ICB therapy in wild-type but not Meflin-deficient mice. Am80-mediated induction of Meflin⁺ CAFs was associated with increases in antibody delivery and M1-like tumor-associated macrophage (TAM) infiltration. Finally, we showed the role of Chemerin produced from CAFs after Am80 administration in the induction of M1-like TAMs. Conclusion: Our data suggested that Am80 administration prior to ICB therapy increases the number of Meflin⁺ rCAFs and ICB efficacy by inducing changes in TAM phenotype.

Background/Aims. The usefulness of macroscopic on-site evaluation (MOSE) during endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has been reported, but a specific method for MOSE has not been established. We aimed to investigate the usefulness of MOSE using a stereomicroscope (S-MOSE) for the diagnosis of solid pancreatic lesions (SPLs). Methods. We reviewed a total of 60 consecutive patients who underwent both S-MOSE and rapid on-site cytopathological evaluation (ROSE) during EUS-FNB between July 2019 and October 2020, and the usefulness of S-MOSE in comparison with histology was evaluated. A 22-gauge Franseen needle was used to perform EUS-FNB in all patients, and only the specimens obtained by the first pass were evaluated. The final diagnosis was based on the surgical specimen or the clinical course consistent with the EUS-FNB results. Results. The final diagnoses of the 60 patients included 45 patients with pancreatic ductal adenocarcinoma, 6 with autoimmune pancreatitis, 4 with mass-forming pancreatitis, 1 with pancreatic metastasis, 2 with pancreatic neuroendocrine tumor, and 2 with intraductal papillary mucinous carcinoma. The histological diagnostic accuracy of the first pass of EUS-FNB was 83.3 (50/60). The agreement between the S-MOSE and the histological diagnosis was 90 (54/60). The positive predictive value of S-MOSE for histological diagnosis was 90.7, which can be an indicator of when to stop the EUS-FNB procedure. There were no immediate or delayed adverse events reported after the FNB based on the chart and medical visit history review. Conclusion. In the EUS-FNB of SPLs, S-MOSE can be an alternative to ROSE for specimen evaluation and has the potential to shorten the procedure time.

Nerves can regulate tumorigenesis and cancer progression. However, clarification of the role of axon guidance molecules in tumorigenesis, innervation, and metastasis is required to better understand the tumor-promoting functions of nerves. Using murine KrasG12D-mutant pancreatic organoids, we screened axon guidance molecules and identified netrin-1 upregulation. Netrin-1 was also upregulated in vivo during pancreatic tumorigenesis in humans and mice. Mutant KRAS and β-adrenergic signaling upregulated netrin-1 and its receptor NEO1 in epithelial cells in part through the MAPK pathway. Ex vivo culture of celiac ganglia showed that netrin-1 promoted the axonogenesis of sympathetic neurons through nerve NEO1. In the Pdx1-Cre;LSL-KrasG12D/+ model, knockout (KO) of Ntn1, which encodes netrin-1, decreased sympathetic innervation and the development of pancreatic intraepithelial neoplasia. Treatment of pancreatic tumor organoids with recombinant netrin-1 enhanced cell growth, epithelial–mesenchymal transition (EMT), and cancer stemness with the upregulation of ZEB1 and SOX9 through NEO1-mediated activation of focal adhesion kinase (FAK). In Pdx1-Cre;LSL-KrasG12D/+;LSL-Trp53R172H/+ mice, Ntn1 KO reduced innervation, FAK phosphorylation, and the features of EMT and stemness to extend mouse survival. In a liver metastasis model of pancreatic ductal adenocarcinoma (PDAC), treatment with a netrin-1–neutralizing antibody or tumoral KO of Neo1 reduced ZEB1 and SOX9 and decreased tumor progression. In contrast, netrin-1 overexpression promoted innervation and the progression of PDAC liver metastasis. These data suggest that the netrin-1/NEO1 axis is a key regulator of PDAC progression, directly influencing cancer cell stemness and EMT while indirectly promoting tumor growth through nerves. Inhibiting the netrin-1 pathway could represent a potential therapeutic approach for PDAC. Significance: Netrin-1 promotes pancreatic tumorigenesis and metastasis directly and indirectly through nerves, highlighting the importance of tumor cell-nerve cross-talk in cancer and the potential of netrin-1 blockade as a treatment strategy.