Activated Wnt signaling promotes growth and progression of AFP-producing gastric cancer in preclinical models

Regulation of Wnt/β-catenin signaling by Marek's disease virus in vitro and in vivo

Marek's disease virus (MDV) infection causes immunosuppression in the host, ultimately inducing tumor formation and causing significant economic losses to the poultry industry. While the abnormal activation of the Wnt/β-catenin signaling pathway is closely associated with the occurrence and development of tumors. However, the relationship between MDV and the Wnt/β-catenin pathway remains unclear. In this study, we found that the MDV RB1B strain, but not the MDV vaccine strain CVI988, activated the Wnt/β-catenin signaling pathway by increasing the phosphorylation level of GSK-3β in chicken embryo fibroblast (CEF). In vivo infection experiments in SPF chickens also confirmed that the RB1B strain activated the Wnt/β-catenin signaling pathway, while the CVI988 strain did not lead to its activation. Moreover, unlike the Meq protein encoded by the CVI988 strain, the Meq protein encoded by the RB1B strain specifically activated the Wnt/β-catenin signaling pathway in CEF cells. The findings from these studies extend our understanding of the regulation of Wnt/β-catenin signaling by MDV, which make a new contribution to understanding the virus-host interactions of MDV.

Alpha-fetoprotein predicts the treatment efficacy of immune checkpoint inhibitors for gastric cancer patients

BACKGROUND

Immune checkpoint inhibitors (ICIs) are commonly used in conjunction with chemotherapy to improve treatment outcomes for patients with gastric cancer. Since AFP could influence immunity by both inhibiting natural killer (NK) cells and regulating negatively the function of dendritic cells, we evaluated the influence of baseline serum alpha-fetoprotein (AFP) levels on the curative effect of ICIs in advanced gastric cancer (AGC) patients.

METHODS

A retrospective analysis was conducted on 158 AGC patients who underwent ICI treatment. The patients were divided into high and low groups based on the AFP threshold of 20 ng/ml. The efficacy of ICI treatment was assessed using objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS).

RESULTS

The higher levels of baseline AFP were found to be associated with a decrease in the effectiveness of ICIs, as evidenced by a DCR of 50.0% in the group with high AFP levels compared to 87.7% in the group with low AFP levels (P < 0.001). Further analysis using Kaplan-Meier survival techniques indicated that a high AFP level was linked to shorter progression-free survival (PFS) (P < 0.001) and overall survival (OS) (P = 0.001) in AGC individuals receiving ICIs. After propensity score matching, a log rank test revealed that the high AFP group had a decrease in median PFS (P = 0.011) and median OS (P = 0.036) compared to the low AFP group. The high AFP levels also showed its association with shorter PFS and OS in the subgroup analysis of ICI plus chemotherapy patients.

CONCLUSIONS

Baseline AFP levels may predict immune checkpoint inhibitor treatment efficacy in AGC patients.

Single-cell characteristics and malignancy regulation of alpha-fetoprotein-producing gastric cancer

OBJECTIVE

To characterize alpha-fetoprotein (AFP)-producing gastric cancer (AFPGC) at the single-cell level and to identify regulatory factors for AFP expression and malignancy.

METHODS

ScRNA-seq was performed on two tumors collected from patients with AFPGC. InferCNV and sub-clustering were applied to identify typical AFPGC cells, followed by AddModuleScore, pathway enrichment, Pseudo-time, and Scenic analyses. Data from a gastric cancer (GC) cohort were collected for conjoint analysis. The analytical results were verified by cell experiments and immunohistochemistry.

RESULTS

AFPGC cells are similar to hepatocytes in transcriptome and transcriptional regulation, with kinetic malignancy-related pathways, compared to the common malignant epithelium. In addition, compared to common GC cells, malignancy-related pathways, such as epithelial-mesenchymal transition (EMT) and angiogenesis, were upregulated in AFPGC. Mechanistically, Dickkopf-1 (DKK1) was found to be associated with AFP expression and malignant phenotype upon combining our scRNA-seq data with a public database, which was further verified by a series of in vitro experiments and immunohistochemistry.

CONCLUSION

We demonstrated the single-cell characteristics of AFPGC and that DKK1 facilitates AFP expression and malignancy.

Alpha-fetoprotein can promote gastric cancer progression via upregulation of metastasis-associated colon cancer 1

High serum alpha-fetoprotein (AFP) level is a predictor of poor prognosis in patients with gastric cancer (GC). AFP-producing GC (AFP-GC) is an aggressive subtype of GC characterized by a high incidence of liver metastasis and high c-Met expression. High expression of metastasis-associated colon cancer 1 (MACC1), which is the transcription activator of c-Met, also predicts a poor prognosis of GC. c-Met is known to be involved in tumor progression into malignant invasive phenotypes. Considering that high c-Met expression is simultaneously positively correlated with high AFP and MACC1 expression levels and that high expression of AFP or MACC1 predicts poor prognosis in GC, we hypothesized that an interaction may exist between AFP and MACC1. In the present study, GC cell lines with AFP-overexpression, MACC1-downregulation and the combination of both transfections were used as experimental models. The relative mRNA and protein expression of c-Met, AFP and MACC1 were analyzed using reverse transcription quantitative PCR and western blotting, respectively. Cell viability was evaluated using Cell Counting Kit-8 assay. Cell invasion and cell migration were examined using Transwell migration assay with and without Matrigel, respectively. The results demonstrated that, compared with the control group, the mRNA and protein expression of MACC1was significantly elevated in the AFP-overexpressed group and in the group with AFP overexpressed and MACC1 downregulated. Furthermore, a significantly enhanced cell viability, migration and invasion were observed in the AFP-overexpressing group, whereas opposite effects were found in the MACC1-downregulating group. In summary, the results from this study indicated that AFP may promote GC progression by stimulating MACC1. This finding may help illustrating the aggressive behaviors of GC in patients with high AFP serum level and AFP-GC.

Both the serum AFP test and AFP/GPC3/SALL4 immunohistochemistry are beneficial for predicting the prognosis of gastric adenocarcinoma

BACKGROUND

Both gastric adenocarcinoma with primitive enterocyte phenotype (GAPEP) (including hepatoid adenocarcinoma) and alpha-fetoprotein (AFP)-producing gastric adenocarcinoma have poor prognoses. However, the value of the serum AFP test and AFP/glypican-3 (GPC3)/spalt-like transcription factor 4 (SALL4) immunohistochemistry is still not clear, and these two methods have not yet been thoroughly compared.

METHODS

We collected 421 consecutive non-neoadjuvant surgically or endoscopically resected gastric adenocarcinoma patients with serum AFP results before surgery (group A). We divided these cases into serum AFP-high (sAFP-H) and serum AFP-normal (sAFP-N) by serum AFP levels, and into GAPEP (expressing AFP, GPC3, or SALL4) and non-GAPEP (nGAPEP) by AFP/GPC3/SALL4 immunohistochemistry results. We also collected 12 non-resected gastric adenocarcinoma patients with serum AFP ≥ 7 ng/mL before treatment (group B). We analyzed these patients' clinicopathological characteristics and prognoses.

RESULTS

Seventeen (4.04%) patients in group A were sAFP-H. These patients were younger and mainly had tubular adenocarcinoma with later pT (P = 0.014) and pN (P = 0.047) categories and more lymphovascular invasion (P < 0.001), perineural spread (P = 0.008), and metastases or recurrence (P < 0.001). For immunohistochemistry, 34 (8.08%) cases were GAPEP, and GAPEP cases also had later pT categories than nGAPEP cases (P = 0.001). Most group B patients with elevated serum AFP (especially > 1000 ng/mL) had simultaneous metastases, mainly liver metastases. Both the serological method and immunohistochemical method were useful for predicting prognosis (AUC _sAFP = 0.625, AUC _A/G/S-IHC = 0.723, z statistic = 1.726, P = 0.084). The serum AFP level (especially > 1000 ng/mL) is more specific (100%), and immunohistochemistry is more sensitive (50%).

CONCLUSION

Both the serum AFP level and immunohistochemical expression of AFP/GPC3/SALL4 can be used to indicate a poor prognosis for gastric adenocarcinoma.

Wnt Signaling: The double-edged sword diminishing the potential of stem cell therapy in congenital heart disease

Stem cell therapy using bone marrow derived or mesenchymal stem cells has become a popular option for cardiovascular disease treatment, however the administration of embryonic stem cells has been mostly experimental. Remarkably, most of these ongoing clinical trials involve adult patients, but little is known regarding the safety and efficacy of stem cell therapy in newborns and children battling congenital heart diseases. Furthermore, cell delivery methods involve the administration of stem cells without pre-differentiation, and without consideration for the consequent process of cardiac development. Interestingly, in-vitro studies have demonstrated that the differentiation of embryonic stem cells into cardiomyocytes imitates the stages of cardiogenesis. Wnt signaling plays a profound role during the earliest stages of cardiogenesis and cardiac differentiation. In fact inappropriate Wnt signaling is associated with numerous cardiac disorders especially congenital heart disease. Furthermore, cell-extracellular matrix interactions were shown to be critical for stem cell differentiation and adequate cardiogenesis. Since extracellular matrix molecules are fundamental for maintenance and repair during heart disease and congenital heart disease, they may offer a novel approach for therapy. Herein we aim to review the critical role of Wnt signaling, as well as the profound importance of cell extracellular matrix interaction, during cardiogenesis. Both of these processes are crucial for precise stem cell differentiation into cardiomyocytes and developing efficacious regenerative therapy for congenital heart disease.

Upregulation of family with sequence similarity 83 member D expression enhances cell proliferation and motility via activation of Wnt/β-catenin signaling and predicts poor prognosis in gastric cancer

Background/aims

Gastric cancer (GC) is the third most common cause of cancer-related death worldwide. The molecular mechanisms underlying the progression of gastric cancer are still not fully elucidated. In this study, we focused on exploring the role of family with sequence similarity 83, member D (FAM83D) in gastric cancer progression.

Methods

The expression of FAM83D in GC tissues was detected by immunohistochemistry (IHC) staining. FAM83D knockdown or overexpression were constructed in AGS and SGC-7901 cells with two distinct siRNA duplexes and lentivirus infection, respectively, to explore the role of FAM83D in gastric cancer progression. Nude mouse xenograft assay was used to further explore the role of FAM83D in tumorigenesis in vivo.

Results

We found that FAM83D mRNA and protein levels were higher in human GC tumor tissues and in GC cell lines, compared with the adjacent normal tissues and non-malignant gastric epithelial cell lines, respectively, and that higher FAM83D expression was correlated with worse overall survival (p<0.0001) and disease-free survival (p<0.0001) in GC patients. Additionally, our results showed that FAM83D overexpression significantly enhanced the proliferation, clonogenicity, and motility of GC cells, whereas FAM83D depletion caused a dramatic increase in the number of cells arrested at the G1 phase of the cell cycle. Consistent with these findings from in vitro experiment, our data also indicated that FAM83D knockdown significantly repressed GC tumor growth in vivo. Furthermore, we demonstrated that FAM83D depletion was associated with reduced Wnt/β-catenin signaling.

Conclusions

This study suggested that FAM83D overexpression enhanced the proliferation, clonogenicity, and motility of GC cells by activating Wnt/β-catenin signaling, and FAM83D may be a promising diagnostic and therapeutic target for human GC.

Wnt Signaling in Cancer Metabolism and Immunity

The Wingless (Wnt)/β-catenin pathway has long been associated with tumorigenesis, tumor plasticity, and tumor-initiating cells called cancer stem cells (CSCs). Wnt signaling has recently been implicated in the metabolic reprogramming of cancer cells. Aberrant Wnt signaling is considered to be a driver of metabolic alterations of glycolysis, glutaminolysis, and lipogenesis, processes essential to the survival of bulk and CSC populations. Over the past decade, the Wnt pathway has also been shown to regulate the tumor microenvironment (TME) and anti-cancer immunity. Wnt ligands released by tumor cells in the TME facilitate the immune evasion of cancer cells and hamper immunotherapy. In this review, we illustrate the role of the canonical Wnt/β-catenin pathway in cancer metabolism and immunity to explore the potential therapeutic approach of targeting Wnt signaling from a metabolic and immunological perspective.