The liver exhibits the highest recovery rate from acute injuries. However, in chronic liver disease, the long-term loss of hepatocytes often leads to adverse consequences such as fibrosis, cirrhosis, and liver cancer. The Wnt signaling plays a pivotal role in both liver regeneration and tumorigenesis. Therefore, manipulating the Wnt signaling has become an attractive approach to treating liver disease, including cancer. Nonetheless, given the crucial roles of Wnt signaling in physiological processes, blocking Wnt signaling can also cause several adverse effects. Recent studies have identified cancer-specific regulators of Wnt signaling, which would overcome the limitation of Wnt signaling target approaches. In this review, we discussed the role of Wnt signaling in liver regeneration, precancerous lesion, and liver cancer. Furthermore, we summarized the basic and clinical approaches of Wnt signaling blockade and proposed the therapeutic prospects of cancer-specific Wnt signaling blockade for liver cancer treatment.

Diffuse-type gastric adenocarcinoma (DGAC) is a deadly cancer often diagnosed late and resistant to treatment. While hereditary DGAC is linked to CDH1 mutations, the role of CDH1/E-cadherin inactivation in sporadic DGAC tumorigenesis remains elusive. We discovered CDH1 inactivation in a subset of DGAC patient tumors. Analyzing single-cell transcriptomes in malignant ascites, we identified two DGAC subtypes: DGAC1 (CDH1 loss) and DGAC2 (lacking immune response). DGAC1 displayed distinct molecular signatures, activated DGAC-related pathways, and an abundance of exhausted T cells in ascites. Genetically engineered murine gastric organoids showed that Cdh1 knock-out (KO), KrasG12D, Trp53 KO (EKP) accelerates tumorigenesis with immune evasion compared with KrasG12D, Trp53 KO (KP). We also identified EZH2 as a key mediator promoting CDH1 loss-associated DGAC tumorigenesis. These findings highlight DGAC’s molecular diversity and potential for personalized treatment in CDH1-inactivated patients.

Background: The clinical impact of SMARCA4 mutations (SMARCA4ms) in gastroesophageal adenocarcinoma (GEA) remains underexplored. This study aimed to examine the association of SMARCA4ms with clinical outcomes and co-occurrence with other gene mutations identified through a next-generation sequencing (NGS) panel in GEA patients. Methods: A total of 256 patients with metastatic or recurrent GEA who underwent NGS panel profiling at the MD Anderson Cancer Center between 2016 and 2022 were included. Comparative analyses were performed to assess clinical outcomes related to SMARCA4ms. The frequency and types of SMARCA4ms and their co-occurrence with other gene mutations were also examined. Results: SMARCA4ms were identified in 19 patients (7.4%). These SMARCA4ms were significantly associated with non-signet ring cell subtype (p = 0.044) and PD-L1 positive expression (p = 0.046). No difference in survival between the SMARCA4m and SMARCA4-normal group was observed (p = 0.84). There were significant associations between SMARCA4ms and FANCA, IGF1R, KRAS, FANCL, and PTEN alterations. Notably, 15 of the 19 SMARCA4m cases involved SNV missense mutations, with frequent co-occurrences noted with TP53, KRAS, ARID1A, and ERBB2 mutations. Conclusions: These results serve as the first comprehensive examination of the relationship between SMARCA4ms and clinical outcomes in GEA.

Unraveling the intricacies of neoadjuvant immune checkpoint blockade in esophageal squamous cell carcinoma: a comprehensive single-cell perspective

Background: Dysregulation of the Hippo signaling pathway, characterized by aberrant activation of the transcriptional coactivators YAP1 and TAZ, drives tumor progression, immunosuppression, and metastasis. Hippo pathway components are emerging therapeutic targets in several solid tumors, however, the expression profiles of Hippo coactivators YAP1, TAZ, and their transcriptional factors TEAD1-4 in gastric cancer peritoneal metastases (GCPMs), and their therapeutic value, are unknown. In this study, we sought to determine the expression status of YAP1, TAZ, and TEAD1-4 in GCPMs and to evaluate whether dual targeting of YAP1 and TAZ provides superior antitumor activity compared with inhibition of either coactivator alone. Methods: Expression of YAP1, TAZ, and TEAD1–4 was examined in GCPMs by single-cell RNA sequencing and co-immunofluorescent staining. Functional studies using genetic knockout and antisense oligonucleotide (ASO) inhibition of YAP1 or TAZ were performed to assess antineoplastic effects in vitro and in vivo. Co-immunoprecipitation and luciferase reporter assays were used to characterize YAP1/TAZ interactions with TEADs and AP-1 components (JUN and FOSB) and to quantify transcriptional activity. Antitumor efficacy was validated in patient-derived xenograft (PDX) and KP-Luc2 syngeneic models. Results: YAP1, TAZ, and TEADs1-4 were highly coexpressed in GCPMs and correlated with poor survival. YAP1 inhibition alone elicited compensatory upregulation of TAZ, while combined inhibition of both coactivators maximally repressed cell proliferation and invasion in vitro, and tumor growth in vivo. Increased TAZ complexation with TEAD4 and AP-1 (c-JUN and FOSB) heterodimer was observed following YAP1 knockdown or pharmacological ASO inhibition. Dual inhibition of YAP1 and TAZ was required to maximally suppress YAP1/TAZ expression and reduce their nuclear accumulation, transactivation of TEAD, and activation of downstream genes. Conclusions: These findings show that combined YAP1 and TAZ inhibition holds promise for the treatment of GCPM, a highly lethal disease with an urgent need for novel treatment options.

Esophageal cancer is the 7th common cancer with the 6th highest cancer mortality rate worldwide. The 5-year survival rate of esophageal cancer is 10 ~ 25%. Esophageal cancer is mainly divided into esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma. ESCC accounts for 80% of all esophageal cancer cases and shows a poor prognosis due to a lack of symptoms at early stages. Given that early diagnosis of ESCC may lead to better outcomes, understanding the biology of ESCC initiation is imperative. To recapitulate the early events of ESCC, we employed the murine esophageal organoid (EO) system recently developed. Based on in silico analyses, we selected nine candidate genes (TP53, CDKN2A, NOTCH1, NOTCH3, KMT2D, KMT2C, FAT1, FAT4, and AJUBA) frequently mutated in ESCC patients. The EOs were then genetically manipulated with the combinatorial ablation of nine genes by CRISPR/Cas9 system. The EOs carrying PN (Trp53 and Notch1 KO), PC (Trp53 and Cdkn2a KO), and PCN (Trp53, Cdkn2a, and Notch1 KO) showed hyperplastic and neoplastic properties with impaired squamous cell differentiation and organoid integrity, compared to the wild-type (WT) EOs. Single-cell RNA-seq (scRNA-seq) analyses of WT, PC, PN, and PCN organoids showed the highest enrichment of ESCC cancer stem cell markers in PCN organoids. Unlike the cell lineage in WT EOs, neoplastic EOs (PC, PN, and PCN) exhibited distinct cell lineage along with multiple root cell clusters. While WT EOs failed to become neoplastic, PN, PC, and PCN EOs displayed the transforming activity in vitro and in vivo xenograft transplantation assays. Intriguingly, in allograft mouse models, while PN organoids-derived cells barely developed tumors, PC and PCN organoids-derived cells developed tumors with marked downregulation of genes related to antigen processing and presentation. These results suggest that combinatorial loss of P53, CDKN2A, and NOTCH1 play a pivotal role in ESCC neoplasia, stemness, and immune checkpoint, unveiling the biology of ESCC initiation. Citation Format: Kyung Pil Ko, Gengyi Zou, Yuanjian Huang, Bongjun Kim, Jie Zhang, Sohee Jun, Jae-Il Park. Modeling and dissecting of esophageal squamous cell carcinoma initiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 943.