The Expression of Yes-Associated Protein (YAP) Maintains Putative Cancer Stemness and Is Associated with Poor Prognosis in Intrahepatic Cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is resistant to most chemotherapeutic agents. Yes-associated protein (YAP) is related to tumor progression; however, its role in ICC remains unknown. We investigated the mechanism underlying YAP-mediated cancer progression by focusing on the property of cancer stem cells (CSCs) in ICC. Immunohistochemistry results revealed the positive YAP expression in 37 of 52 resected ICC cases. Those with positive YAP expression showed poor prognosis in Kaplan-Meier analysis (P = 0.023). YAP expression was associated with vimentin and the putative CSC marker, hepatic oval cell marker 6 (OV-6). The knockdown of YAP expression using specific siRNAs in ICC cells decreased octamer-binding transcription factor 4 (OCT4) expression in Western blot analyses and OV-6 and CD133 expression in flow cytometry analysis. Verteporfin, a YAP inhibitor, decreased N-cadherin and OCT4 expression in Western blot analyses. In vitro sphere formation and anoikis resistance assays revealed the impairment in CSC property and anoikis resistance in response to the decrease in YAP expression. Verteporfin treatment activated the protein kinase B/mechanistic target of rapamycin signaling pathway and dramatically impaired IL-6-stimulated STAT3 phosphorylation in ICC cells. The combination of verteporfin and rapamycin, an inhibitor of mechanistic target of rapamycin phosphorylation, inhibited cell proliferation and tumor growth. In conclusion, verteporfin regulates multiple signaling pathways and, in combination with rapamycin, might be a promising therapeutic strategy for ICC treatment.

FRA1 controls acinar cell plasticity during murine KrasG12D-induced pancreatic acinar to ductal metaplasia.

Acinar cells have been proposed as a cell-of-origin for pancreatic ductal adenocarcinoma (PDAC) after undergoing acinar-to-ductal metaplasia (ADM). ADM can be triggered by pancreatitis, causing acinar cells to de-differentiate to a ductal-like state. We identify FRA1 (gene name Fosl1) as the most active transcription factor during KrasG12D acute pancreatitis-mediated injury, and we have elucidated a functional role of FRA1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D. Using a gene regulatory network and pseudotime trajectory inferred from single-nuclei ATAC-seq and bulk RNA sequencing (RNA-seq), we hypothesized a regulatory model of the acinar-ADM-pancreatic intraepithelial neoplasia (PanIN) continuum and experimentally validated that Fosl1 knockout mice are delayed in the onset of ADM and neoplastic transformation. Our study also identifies that pro-inflammatory cytokines, such as granulocyte colony stimulating factor (G-CSF), can regulate FRA1 activity to modulate ADM. Our findings identify that FRA1 is a mediator of acinar cell plasticity and is critical for acinar cell de-differentiation and transformation.

LIN28B promotes cell invasion and colorectal cancer metastasis via CLDN1 and NOTCH3.

The RNA-binding protein LIN28B is overexpressed in over 30% of patients with colorectal cancer (CRC) and is associated with poor prognosis. In the present study, we unraveled a potentially novel mechanism by which LIN28B regulates colonic epithelial cell-cell junctions and CRC metastasis. Using human CRC cells (DLD-1, Caco-2, and LoVo) with either knockdown or overexpression of LIN28B, we identified claudin 1 (CLDN1) tight junction protein as a direct downstream target and effector of LIN28B. RNA immunoprecipitation revealed that LIN28B directly binds to and posttranscriptionally regulates CLDN1 mRNA. Furthermore, using in vitro assays and a potentially novel murine model of metastatic CRC, we show that LIN28B-mediated CLDN1 expression enhances collective invasion, cell migration, and metastatic liver tumor formation. Bulk RNA sequencing of the metastatic liver tumors identified NOTCH3 as a downstream effector of the LIN28B/CLDN1 axis. Additionally, genetic and pharmacologic manipulation of NOTCH3 signaling revealed that NOTCH3 was necessary for invasion and metastatic liver tumor formation. In summary, our results suggest that LIN28B promotes invasion and liver metastasis of CRC by posttranscriptionally regulating CLDN1 and activating NOTCH3 signaling. This discovery offers a promising new therapeutic option for metastatic CRC to the liver, an area where therapeutic advancements have been relatively scarce.

Engineered hydrogel reveals contribution of matrix mechanics to esophageal adenocarcinoma and identifies matrix-activated therapeutic targets.

Increased extracellular matrix (ECM) stiffness has been implicated in esophageal adenocarcinoma (EAC) progression, metastasis, and resistance to therapy. However, the underlying protumorigenic pathways are yet to be defined. Additional work is needed to develop physiologically relevant in vitro 3D culture models that better recapitulate the human tumor microenvironment and can be used to dissect the contributions of matrix stiffness to EAC pathogenesis. Here, we describe a modular, tumor ECM-mimetic hydrogel platform with tunable mechanical properties, defined presentation of cell-adhesive ligands, and protease-dependent degradation that supports robust in vitro growth and expansion of patient-derived EAC 3D organoids (EAC PDOs). Hydrogel mechanical properties control EAC PDO formation, growth, proliferation, and activation of tumor-associated pathways that elicit stem-like properties in the cancer cells, as highlighted through in vitro and in vivo environments. We also demonstrate that the engineered hydrogel serves as a platform for identifying potential therapeutic targets to disrupt the contribution of protumorigenic matrix mechanics in EAC. Together, these studies show that an engineered PDO culture platform can be used to elucidate underlying matrix-mediated mechanisms of EAC and inform the development of therapeutics that target ECM stiffness in EAC.

p53 Gain-of-Function Mutation Induces Metastasis via BRD4-Dependent CSF-1 Expression.

TP53 mutations are frequent in esophageal squamous cell carcinoma (ESCC) and other SCCs and are associated with a proclivity for metastasis. Here, we report that colony-stimulating factor-1 (CSF-1) expression is upregulated significantly in a p53-R172H-dependent manner in metastatic lung lesions of ESCC. The p53-R172H-dependent CSF-1 signaling, through its cognate receptor CSF-1R, increases tumor cell invasion and lung metastasis, which in turn is mediated in part through Stat3 phosphorylation and epithelial-to-mesenchymal transition (EMT). In Trp53R172H tumor cells, p53 occupies the Csf-1 promoter. The Csf-1 locus is enriched with histone 3 lysine 27 acetylation (H3K27ac), which is likely permissive for fostering an interaction between bromodomain-containing domain 4 (BRD4) and p53-R172H to regulate Csf-1 transcription. Inhibition of BRD4 not only reduces tumor invasion and lung metastasis but also reduces circulating CSF-1 levels. Overall, our results establish a novel p53-R172H-dependent BRD4-CSF-1 axis that promotes ESCC lung metastasis and suggest avenues for therapeutic strategies for this difficult-to-treat disease. SIGNIFICANCE: The invasion-metastasis cascade is a recalcitrant barrier to effective cancer therapy. We establish that the p53-R172H-dependent BRD4-CSF-1 axis is a mediator of prometastatic properties, correlates with patient survival and tumor stages, and its inhibition significantly reduces tumor cell invasion and lung metastasis. This axis can be exploited for therapeutic advantage. This article is featured in Selected Articles from This Issue, p. 2489.

A case of successfully resected metachronous gastric and gallbladder metastases from pancreatic body cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) readily metastasizes to the lymph nodes, liver, lung, and peritoneum; however, gastric and gallbladder metastases are rare. We report a case of metachronous gastric and gallbladder metastases from PDAC. CASE PRESENTATION: The patient is a 71-year-old man who underwent distal pancreatectomy for PDAC. Seventeen months after the surgery, a 30-mm nodule was detected at the lesser curvature of the stomach, which was diagnosed as recurrence of PDAC in the lymph nodes. He then received gemcitabine and S-1 combination chemotherapy for 6 months. Because tumor size remained approximately the same and tumor marker levels decreased, total gastrectomy and cholecystectomy were performed. Pathological examination showed well-differentiated tubular adenocarcinoma in the subserosa and muscularis propria of the stomach and gallbladder. The patient remains alive at 41 months after the second surgery with liver metastasis. CONCLUSION: We reported a rare case of metachronous gastric and gallbladder metastases from pancreatic body cancer.

Glucagonoma With Necrolytic Migratory Erythema: Metabolic Profile and Detection of Biallelic Inactivation of DAXX Gene.

Context: Necrolytic migratory erythema (NME) occurs in approximately 70% of patients with glucagonoma syndrome. Excessive stimulation of metabolic pathways by hyperglucagonemia, which leads to hypoaminoacidemia, contributes to NME pathogenesis. However, the molecular pathogenesis of glucagonoma and relationships between metabolic abnormalities and clinical symptoms remain unclear. Patient: A 53-year-old woman was referred to our hospital with a generalized rash and weight loss. NME was diagnosed by histopathological examination of skin biopsy tissue. Laboratory tests revealed diabetes, hyperglucagonemia, marked insulin resistance, severe hypoaminoacidemia, ketosis, and anemia. Enhanced computed tomography scans detected a 29-mm pancreatic hypervascular tumor, which was eventually diagnosed as glucagonoma. Preoperative treatment with octreotide long-acting release reduced the glucagon level, improved the amino acid profile, and produced NME remission. Surgical tumor excision normalized the metabolic status and led to remission of symptoms, including NME. Interventions: Whole-exome sequencing (WES) and subsequent targeted capture sequencing, followed by Sanger sequencing and pyrosequencing, identified biallelic alteration of death-domain associated protein (DAXX) with a combination of loss of heterozygosity and frameshift mutations (c.553_554del:p.R185fs and c.1884dupC:p.C629fs) in the glucagonoma. Consistently, immunohistochemistry confirmed near-absence of DAXX staining in the tumor cells. Tumor expression of glucagon and somatostatin receptor subtype 2 and 3 messenger RNA was markedly upregulated. Conclusions: This is a report of glucagonoma with biallelic inactivation of DAXX determined by WES. The tumor manifested as glucagonoma syndrome with generalized NME. This case showed the relationship between hypoaminoacidemia and NME status. Further investigations are required to elucidate the underlying mechanisms of NME onset and glucagonoma tumorigenesis.

Quantitative assessment of orbital fractures in Asian patients: CT measurement of orbital volume.

Enophthalmos is caused by an increase of orbital volume after blowout fracture and is one of the most critical complications of such fractures, but is often masked by swelling soon after injury. If surgery is performed after swelling resolves, it becomes more difficult to treat enophthalmos because of atrophy and fibrosis. Accordingly, it is important to estimate the severity of enophthalmos soon after injury. We developed a new criterion for determining whether orbital fractures are indicated for surgery in Asian patients using analysis of orbital volume. We retrospectively calculated the orbital volume of patients treated surgically or conservatively and analyzed the correlation between changes of orbital volume and the severity of enophthalmos. Regression analysis of the correlation between enophthalmos and increased orbital volume (y = 0.8x + 0.2; correlation coefficient: 0.92) showed that enophthalmos of 2.0 mm corresponded to an increase in orbital volume of 2.25 cm3. This result is similar to data reported previously for Caucasian patients - enophthalmos of 2.0 mm is a common surgical indication worldwide. Our results suggest that an increase of orbital volume of >2.25 cm3 could be a new criterion for surgical treatment of blowout fractures in Asians.

Successful radical surgical resection of initially unresectable intrahepatic cholangiocarcinoma by downsizing chemotherapy with gemcitabine plus cisplatin: a case report.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a subtype of biliary tract cancer (BTC). Recently, downsizing chemotherapy has been applied to initially unresectable BTCs, including ICC. CASE PRESENTATION: We report a case of liver resection in a 23-year-old woman who was diagnosed with initially unresectable ICC attached to the inferior vena cava, with portal vein (PV) cavernous transformation. Positron emission tomography (PET) showed fluorodeoxyglucose (FDG) uptake in the para-aortic lymph nodes. Upon using downsizing chemotherapy (the combination of gemcitabine [GEM] and cisplatin [CDDP]), the size of tumor reduced by 55% and FDG uptake in the para-aortic lymph node metastases disappeared. A right hemihepatectomy was performed, along with dissection of lymph nodes, including the para-aortic lymph nodes. The PV cavernous transformation was preserved to maintain collateral flow as much as possible, as it was considered to originate from a congenital anomaly. Pathological examination revealed that R0 resection was performed and that there were no viable neoplastic cells remaining in the para-aortic lymph nodes. The patient is alive at 31 months after initial treatment, with a local recurrence. CONCLUSION: Downsizing chemotherapy with GEM plus CDDP followed by radical surgical resection is an attractive treatment for initially unresectable BTC.